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1
Kärkkäinen, Ela, Åsa Älgbrant, and Simon Kronberg. "Fibres from agricultural hemp waste." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-26573.
Full textAbstract:
There is an increasing demand for natural fibres in the textile industry as a consequence of the negative impact of the industry on the environment. Svensk Hampaindustri (SHI) is currently growing hemp in Sweden for its seeds. This leaves residue in the form of hemp stems that could be processed for textile products. Today this residue material is not used for anything, however there is a desire that it could be used for added value. This study investigates the possibility of extracting fibres from the hemp residue mechanically and using them in applications. Hemp, a variety of Cannabis sativa L., is a multipurpose low-input crop cultivated for its seeds, fibres and hurds. Hemp fibre is a bast fibre, derived from the plant’s outer stem tissues. To extract hemp fibres from hemp stems, the first step is to separate the fibre bundles from the other, non-fibrous parts of the stem. This process is done using various mechanical methods. In order to ease the separation, hemp stems are retted. Retting is a biological process that uses enzymatic activities to degrade the pectins and thus making the separation easier. Retting is one of the most considerable challenges towards a wider use of hemp fibres. Water retting offers high fibre-quality but consumes high amounts of water and causes effluents in the wastewater. Dew retting offers a high fibre yield and low labour costs but will result in a lower fibre-quality. Alternative methods that can contribute with a more consistent fibre yield and quality are available, but with an economic uncertainty for the farmers that limits the competitiveness of the hemp fibre. The hemp material provided by SHI was unretted and needed to be broken down by means of mechanical processing in order to extract the fibres. This was done using a domestic blender. The crushed material was then carded using a hand carding machine to achieve oriented and clean fibres. The obtained fibres were then evaluated for their length and fineness. Three different types of nonwoven were made using the hemp fibres: NW1, NW2 and NW3. NW1 consists of 100% hemp, whereas NW2 and NW3 are 80/20 blends of hemp and PLA. NW1 was needle punched, NW2 was thermally bonded and NW3 was manufactured by both thermal bonding and needle punching. The produced nonwovens were evaluated by their air permeability, thermal conductivity, sound absorption, drapability and tensile strength. The results from the study showed that it is possible to extract unretted fibres using mechanical methods. The fibres are quite coarse and therefore more suitable for industrial applications. The different production methods for the nonwovens gave different results which supports the diversity of hemp applications. This study suggests that the residue should be used rather than be disposed of.
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Islam, Mohammad Saiful. "The Influence of Fibre Processing and Treatments on Hemp Fibre/Epoxy and Hemp Fibre/PLA Composites." The University of Waikato, 2008. http://hdl.handle.net/10289/2627.
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In recent years, due to growing environmental awareness, considerable attention has been given to the development and production of natural fibre reinforced polymer (both thermoset and thermoplastic) composites. The main objective of this study was to reinforce epoxy and polylactic acid (PLA) with hemp fibre to produce improved composites by optimising the fibre treatment methods, composite processing methods, and fibre/matrix interfacial bonding. An investigation was conducted to obtain a suitable fibre alkali treatment method to: (i) remove non-cellulosic fibre components such as lignin (sensitive to ultra violet (UV) radiation) and hemicelluloses (sensitive to moisture) to improve long term composites stability (ii) roughen fibre surface to obtain mechanical interlocking with matrices (iii)expose cellulose hydroxyl groups to obtain hydrogen and covalent bonding with matrices (iv) separate the fibres from their fibre bundles to make the fibre surface available for bonding with matrices (v) retain tensile strength by keeping fibre damage to a minimum level and (vi) increase crystalline cellulose by better packing of cellulose chains to enhance the thermal stability of the fibres. An empirical model was developed for fibre tensile strength (TS) obtained with different treatment conditions (different sodium hydroxide (NaOH) and sodium sulphite (Na2SO3) concentrations, treatment temperatures, and digestion times) by a partial factorial design. Upon analysis of the alkali fibre treatments by single fibre tensile testing (SFTT), scanning electron microscopy (SEM), zeta potential measurements, differential thermal analysis/thermogravimetric analysis (DTA/TGA), wide angle X-ray diffraction (WAXRD), lignin analysis and Fourier transform infrared (FTIR) spectroscopy, a treatment consisting of 5 wt% NaOH and 2 wt% Na2SO3 concentrations, with a treatment temperature of 120oC and a digestion time of 60 minutes, was found to give the best combination of the required properties. This alkali treatment produced fibres with an average TS and Young's modulus (YM) of 463 MPa and 33 GPa respectively. The fibres obtained with the optimised alkali treatment were further treated with acetic anhydride and phenyltrimethoxy silane. However, acetylated and silane treated fibres were not found to give overall performance improvement. Cure kinetics of the neat epoxy (NE) and 40 wt% untreated fibre/epoxy (UTFE) composites were studied and it was found that the addition of fibres into epoxy resin increased the reaction rate and decreased the curing time. An increase in the nucleophilic activity of the amine groups in the presence of fibres is believed to have increased the reaction rate of the fibre/epoxy resin system and hence reduced the activation energies compared to NE. The highest interfacial shear strength (IFSS) value for alkali treated fibre/epoxy (ATFE) samples was 5.2 MPa which was larger than the highest value of 2.7 MPa for UTFE samples supporting that there was a stronger interface between alkali treated fibre and epoxy resin. The best fibre/epoxy bonding was found for an epoxy to curing agent ratio of 1:1 (E1C1) followed by epoxy to curing agent ratios of 1:1.2 (E1C1.2), 1: 0.8 (E1C0.8), and finally for 1:0.6 (E1C0.6). Long and short fibre reinforced epoxy composites were produced with various processing conditions using vacuum bag and compression moulding. A 65 wt% untreated long fibre/epoxy (UTLFE) composite produced by compression moulding at 70oC with a TS of 165 MPa, YM of 17 GPa, flexural strength of 180 MPa, flexural modulus of 10.1 GPa, impact energy (IE) of 14.5 kJ/m2, and fracture toughness (KIc) of 5 MPa.m1/2 was found to be the best in contrast to the trend of increased IFSS for ATFE samples. This is considered to be due to stress concentration as a result of increased fibre/fibre contact with the increased fibre content in the ATFE composites compared to the UTFE composites. Hygrothermal ageing of 65 wt% untreated and alkali treated long and short fibre/epoxy composites (produced by curing at 70oC) showed that long fibre/epoxy composites were more resistant than short fibre/epoxy composites and ATFE composites were more resistant than UTFE composites towards hygrothermal ageing environments as revealed from diffusion coefficients and tensile, flexural, impact, fracture toughness, SEM, TGA, and WAXRD test results. Accelerated ageing of 65 wt% UTLFE and alkali treated long fibre/epoxy (ATLFE) composites (produced by curing at 70oC) showed that ATLFE composites were more resistant than UTLFE composites towards hygrothermal ageing environments as revealed from tensile, flexural, impact, KIc, SEM, TGA, WAXRD, FTIR test results. IFSS obtained with untreated fibre/PLA (UFPLA) and alkali treated fibre/PLA (ATPLA) samples showed that ATPLA samples had greater IFSS than that of UFPLA samples. The increase in the formation of hydrogen bonding and mechanical interlocking of the alkali treated fibres with PLA could be responsible for the increased IFSS for ATPLA system compared to UFPLA system. Long and short fibre reinforced PLA composites were also produced with various processing conditions using compression moulding. A 32 wt% alkali treated long fibre PLA composite produced by film stacking with a TS of 83 MPa, YM of 11 GPa, flexural strength of 143 MPa, flexural modulus of 6.5 GPa, IE of 9 kJ/m2, and KIc of 3 MPa.m1/2 was found to be the best. This could be due to the better bonding of the alkali treated fibres with PLA. The mechanical properties of this composite have been found to be the best compared to the available literature. Hygrothermal and accelerated ageing of 32 wt% untreated and alkali treated long fibre/PLA composites ATPLA composites were more resistant than UFPLA composites towards hygrothermal and accelerated ageing environments as revealed from diffusion coefficients and tensile, flexural, impact, KIc, SEM, differential scanning calorimetry (DSC), WAXRD, and FTIR results. Increased potential hydrogen bond formation and mechanical interlocking of the alkali treated fibres with PLA could be responsible for the increased resistance of the ATPLA composites. Based on the present study, it can be said that the performance of natural fibre composites largely depend on fibre properties (e.g. length and orientation), matrix properties (e.g. cure kinetics and crystallinity), fibre treatment and processing methods, and composite processing methods.
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Korte, Sandra. "Processing-Property Relationships of Hemp Fibre." Thesis, University of Canterbury. Mechanical Engineering, 2006. http://hdl.handle.net/10092/1175.
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There is great interest in the plant Cannabis sativa (hemp) as a source of technical fibres for the reinforcement of polymers in composite materials due to its high mechanical properties. As a natural fibre hemp also offers biodegradabilty and is therefore an inexpensive and renewable alternative to glass fibres However, the environmental benefits of natural fibres cannot be fully exploited if the manufacturing of their composites involves polluting processing steps. Unfortunately, there is still a lack of environmetally sustainable processing methods yielding technical fibres of sufficient quality. Enzyme application as a biotechnological processing method is a good candidate for this aim and is therefore actively investigated at present. In this work the effects of a range of enzymes on the morphological, compositional and mechanical properties of hemp was investigated. The enzymes were firstly characterised and then applied to hemp fibre for differing periods of time. After visual inspection, a set of fibre samples were selected and subjected to further analysis by Fourier-Transform Infrared Spectroscopy (FTIR), tensile testing and scanning electron microscopy (SEM). The commercial formulation Pectinex® Ultra-SL emerged as the most efficient in terms of treatment time and fibre quality. The effectiveness of treatments was further investigated by developing a novel experimental method that correlates the adhesion forces measured by atomic force microscopy (AFM) on the fibre surface to the properties of the fibres or composites. In order to identify correlations between the adhesion forces and fibre or composite properties, hemp fibre was subjected to four distinctly different treatments to obtain significant differences between fibre properties. The fibres and composites were then analyzed using a combination of FTIR, tensile testing, 3-point bend testing, dynamic mechanical analysis (DMA) and SEM. Based on this comprehensive dataset the AFM data was correlated using the software SPSS. The information derived from AFM (adhesion forces and surface topology) was useful in the clarification of fibre modifications evoked by the treatments.
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Patel, Harish. "Hemp fibre reinforced sheet moulding compounds." Thesis, Queen Mary, University of London, 2012. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8783.
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Glass fibres are by far the most extensively used fibre reinforcement in thermosetting composites because of their excellent cost-performance ratio. However, glass fibres have some disadvantages such as non- renewability and problems with ultimate disposal at the end of a materials lifetime since they cannot be completely thermally incinerated. The possibility of replacing E-glass fibres with hemp fibres as reinforcement in sheet moulding compounds (SMC) is examined in this thesis. The composites are manufactured with existing SMC processing techniques and similar resin formulation as used in the commercial industry. An attempt is made to enhance/optimise the mechanical properties of hemp/polyester composites. For this the fibre-matrix interface is modified via chemical modifications with alkaline and silane treatments. Influence of hemp fibre volume fraction, calcium carbonate (CaCO3)filler content and fibre-matrix interface modification on the mechanical properties of hemp fibre-mat-reinforced sheet moulding compounds (H-SMC) is studied. The results of H-SMC composites are compared to E-glass fibre-reinforced sheet moulding compounds (G-SMC). In order to get a better insight in the importance of these different parameters for the optimisation of composite performance, the experimental results are compared with theoretical predictions made using modified micromechanical models such as Cox-Krenchel and Kelly- Tyson for random short-fibre-reinforced composites. These models are supplemented with parameters of composite porosity to improve the prediction of natural fibre composite tensile properties. The influence of impact damage on the residual exural strength of the H-SMC composites is investigated to improve the understanding of impact response of natural fibre reinforced composites. The result of penetration and absorbed energies during non-penetrating impact of H-SMC composites are investigated and compared to values for G-SMC. A simple mechanistic model has been developed for H-SMC composites and is used to get an insight into the impact behaviour of these composite as well as to provide a guideline to compare the experimental results with theoretically calculated data. The fracture toughness properties in terms of the critical-stress-intensity factor KIc, and critical strain energy release rate, GIc, of H-SMC and G-SMC composites are studied using the compact tension (CT) method. It was shown that fracture toughness of H-SMC composites is significantly lower than that of glass fibre reinforced composites (G- SMC). However, results show that with an optimum combination of fibre volume fraction, (CaCO3) filler and surface treatment of the hemp fibres can result in H-SMC composites that have fracture toughness properties that can be exploited for low to medium range engineering applications. It is recommended that to further improve the fracture toughness properties of these natural fibre reinforced composites more research needs to be devoted to the optimization of the fibre-matrix interface properties and ways of reducing porosity content in these composites. Finally, environmental impact of H-SMC composite with conventional G-SMC composite for automotive and non-automotive applications was compared. The composites were assumed to be made in a traditional SMC manufacturing method. Two different types of performance requirements; i.e. stiffness and strength were investigated for both the non-automotive and automotive parts. Two different disposal scenarios: landfill and incineration of the SMC product at the end of life was considered. The LCA results demonstrate that the environmental impact of H-SMC composites is lower than the reference G-SMC composites. G-SMC composites have a significantly higher environmental impact on climate change, acidification and fossil fuels than H-SMC composites. Where as H-SMC composites have a much higher impact on land use and ecotoxicity than G-SMC composites.
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Dasong, Dai. "Hemp nanocellulose : fabrication, characterisation and application." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/11311.
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Nanocellulose has gained lots of attentions in recent years due to the development of nanotechnology. Thousands of publications have been reported about the fabrication, characterization and application of nanocellulose, among which most of the nanocelluloses were fabricated from the microcrystalline cellulose (MCC) or pulp, and only two methods about the nanocellulose fabrication have been reported, i.e. sulphuric acid hydrolysis and mechanical treatment. The sulphuric acid method can only obtain low yield of nanocellulose and the mechanical treatment can not fabricate nanocellulose with high crystallinity index (CI) and well separation. These problems limit the scale up of nanocellulose to industrial area. Moreover, none of works has reported the application of nanocellulose for the modification of natural fibres and only a few works reported the reinforcement of epoxy with nanocellulose. In this this research, we fabricated nanocellulose directly from hemp fibres by employing oxidation/sonication method with the aim to solve the main problems of nanocellulose fabrication with sulphuric acid hydrolysis or mechanical. By using this method the yield of nanocellulose could up to 54.11 % and the crystallinity of nanocellulose was 86.59 %. In order to expand the application of nanocellulose, we investigated the modification of natural fibres (hemp) with nanocellulose and the fabrication of nanocomposite. Two-step modification, i.e. dodecyltrimethylammonium bromide (DTAB) pretreatment and nanocellulose modification, was used to modify hemp fibres. In this process, we systematically investigated the deformation of hemp fibres, revealed the mechanism of deformation on the mechanical property of single fibre by using Fourier transform infrared spectroscopy (FTIR) and investigated the effect of deformation on the hemp fibre modification with nanocellulose by using energy dispersive X-ray (EDX). The two-step modification increased the mechanical properties of hemp fibres significantly. Compared with raw hemp fibres, the modulus, tensile stress and tensile strain of the two-step nanocellulose modified hemp fibres increase by 36.13 %, 72.80 % and 67.89 %, respectively. Moreover, two-step modification facilitated the improvement of interfacial property of fibres. This novel natural fibre modification provides new clue to exploit nanocellulose as a green chemical agent for natural fibres modification. We modified nanocellulose by using curing agent of epoxy---diethylenetriamine (DETA). This modification could increase the dispersity of nanocellulose in epoxy and reinforce epoxy. Compared with epoxy, the modulus, tensile stress and tensile strain of the modified nanocellulose/epoxy nanocomposite increased 1.42 %, 15.44 % and 27.47 %, respectively.
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Britt, Kadie Elizabeth. "Insect pest management in hemp in Virginia." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103014.
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For the first time in many decades, a hemp pilot program was initiated in Virginia in 2016. Outdoor surveys were conducted in the 2017 and 2018 field seasons to record insect presence and feeding injury to plants. Multiple insect pests were present, including corn earworm (Helicoverpa zea [Boddie]) (Lepidoptera: Noctuidae), brown marmorated stink bug (Halyomorpha halys [Stål]) (Hemiptera: Pentatomidae), and cannabis aphid (Phorodon cannabis) (Hemiptera: Aphididae). In 2019, indoor production surveys revealed that cannabis aphid, twospotted spider mite (Tetranychus urticae Koch) (Acari: Tetranychidae), and hemp russet mite (Aculops cannabicola [Farkas]) (Acari: Eriophyidae) would likely cause production issues. Very little is known about the impact of insect defoliation in hemp so studies were conducted in 2018-2020 to determine impacts on yield and cannabinoid content of grain and cannabinoid variety hemp due to leaf surface area loss. In Virginia over two growing seasons, manual removal of leaf tissue in grain and CBD cultivars did not significantly impact observable effects on physical yield (seed or bud weight) or cannabinoid content (CBD or THC) at time of harvest. Corn earworm is the major pest of hemp produced outdoors and studies occurred to evaluate monitoring and management strategies. Pheromone traps may be valuable in determining when corn earworm moths are present in the vicinity of hemp fields but are not useful in predicting larval presence in buds or final crop damage. Larval presence and final crop damage are related. Brown marmorated stink bug does not appear to be a concern in hemp, at least at this time.Doctor of Philosophy
For the first time in many decades, a hemp pilot program was initiated in Virginia in 2016. Outdoor surveys were conducted in the 2017 and 2018 field seasons to record insect presence and feeding injury to plants. Multiple insect pests were present, including corn earworm, brown marmorated stink bug, and cannabis aphid. In 2019, indoor production surveys revealed that cannabis aphid, twospotted spider mite, and hemp russet mite would likely cause production issues. Very little is known about the impact of leaf area loss due to insect feeding in hemp so studies were conducted in 2018-2020 to determine impacts on yield and cannabinoid content of grain and cannabinoid variety hemp due to leaf surface area loss. In Virginia over two growing seasons, manual removal of leaf tissue in grain and CBD cultivars did not significantly impact observable effects on physical yield (seed or bud weight) or cannabinoid content (CBD or THC) at time of harvest. Corn earworm is the major pest of hemp produced outdoors and studies occurred to evaluate monitoring and management strategies. Pheromone traps may be valuable in determining when corn earworm moths are present in the vicinity of hemp fields but are not useful in predicting larval presence in buds or final crop damage. Larval presence and final crop damage are related. Brown marmorated stink bug does not appear to be a concern in hemp, at least at this time.
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Beckermann, Gareth. "Performance of Hemp-Fibre Reinforced Polypropylene Composite Materials." The University of Waikato, 2007. http://hdl.handle.net/10289/2543.
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Increasing worldwide environmental awareness is encouraging scientific research into the development of cheaper, more environmentally friendly and more sustainable construction and packaging materials. Natural fibre reinforced thermoplastic composites are strong, stiff, lightweight and recyclable, and have the potential to meet this need. Industrial hemp fibre is amongst the strongest of the natural fibres available, and possesses a similar specific stiffness to E-glass, but with additional benefits such as low cost and low production energy requirements. The favourable mechanical properties of hemp, however, have yet to be transferred successfully to thermoplastic-matrix composite materials. The aim of this thesis was to achieve a greater understanding of the various parameters that contribute to composite strength and stiffness, and to manipulate these parameters in order to produce an improved hemp fibre reinforced polypropylene composite material. Hemp fibre was alkali treated at elevated temperatures in a small pressure vessel with either a solution of 10wt% NaOH or 5wt% NaOH / 2wt% Na2SO3. Single fibre tensile tests were performed on treated and untreated fibres, and it was found that the NaOH/Na2SO3 treatment produced the strongest and stiffest fibres with a good level of fibre separation. Lignin tests revealed that both alkali treatments were effective in the removal of lignin from hemp fibre, and XRD analysis showed that both alkali treatments resulted in increases in the hemp fibre crystallinity index. TGA and DTA analysis showed that the alkali fibre treatments improved the thermal stability of the treated hemp fibre when compared to the untreated fibre. Alkali treated hemp fibre, polypropylene and a maleic anhydride modified polypropylene (MAPP) coupling agent were compounded in a twin-screw extruder, and injection moulded into composite tensile test specimens. A range of composites with different fibre and MAPP contents were produced and tested. Tensile tests revealed that the optimum composite consisted of polypropylene with 40wt% NaOH/Na2SO3 treated hemp fibre and 4wt% MAPP, and had a tensile strength of 50.5 MPa and a Young's modulus of 5.31 GPa, respectively. The effect of MAPP on the fibre/matrix interface of NaOH/Na2SO3 treated hemp fibre/polypropylene composites was assessed by means of the single fibre fragmentation test. A composite consisting of NaOH/Na2SO3 treated fibres in a matrix of 4wt% MAPP and polypropylene was found to have a critical fibre length of 0.83mm and an interfacial shear strength of 16.1 MPa. The effects of MAPP on the composite fracture mechanisms were evaluated by means of SEM microscopy. TGA and DTA analysis showed that untreated hemp fibre composites and NaOH/Na2SO3 treated hemp fibre composites, each with a matrix of 4% MAPP and polypropylene, were less thermally stable than the polypropylene matrix alone. The Bowyer-Bader model was used to model the strength of an injection moulded composite with a normal fibre length distribution, consisting of 40wt% NaOH/Na2SO3 treated fibre, 4% MAPP and polypropylene. A theoretical composite tensile strength of 149 MPa was obtained from the model, based on the assumption that all the fibres were axially aligned in the composite. Composites with long, axially aligned fibres were produced using a novel solution mixing technique, where the polymer matrix and MAPP coupling agent were dissolved in a solvent and then precipitated inside an aligned fibre mat. Significant improvements in tensile strength and Young's modulus were achieved for solution mixed composites compared to composites produced by means of extrusion and injection moulding. The strongest solution mixed composite had a tensile strength of 84.7 MPa, and consisted of 56wt% NaOH/Na2SO3 treated fibre, 4% MAPP and polypropylene; and the stiffest injection moulded composite had a Young's modulus of 16.0 GPa, and consisted of 63wt% NaOH/Na2SO3 treated fibre, 4% MAPP and polypropylene.
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Gross, Christopher D. "Structural enhancement of timber framing using hemp-lime." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.571876.
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The world is facing increasing pressures to reduce the amount of energy and resources that are being used. The UK government has targets to reduce carbon emissions and energy usage. Within the UK buildings are a significant contributor towards both energy and material usage. One approach to reduce the energy and carbon emissions from construction is to use natural materials that require minimal processing and energy input such as straw, timber, unfired earth and hemp-lime. Hemp-lime is a composite solid wall insulating material made from hemp shiv and a lime based binder and water which can be cast between shutters or spray applied. Hemp-lime is typically used with a load bearing timber studwork frame. Current design practice assumes that hemp-lime is a nonstructural material and only provides the insulation to the wall construction. However, as it encapsulates the studs it has to potential to enhance their load capacity by preventing buckling and resisting in-plane forces. This study aimed to establish the contribution of the hemp-lime to the structural performance of composite hemp-lime and studwork frame walls under three loading conditions; vertical compression, in-plane racking and out-of-plane bending. Both theoretical analysis and experimental testing were undertaken in order to establish the contribution. Tradical HF hemp shiv and Tradical HB binder were used to mix hemplime with a density of 275kg/m3. The wall constructions were initially theoretically analysed using existing approaches and both the stiffness and strength of the wall panels were calculated. Experimental testing was undertaken on 24 full size wall panels. Fifteen were tested with compressive loads, five with in-plane racking loads and four with out-of-plane bending loads. Initially two walls were tested with a concentric compressive load applied to the top of the encapsulated timber studs. The studs were shown to be restrained by the hemp-lime preventing buckling and increasing the failure load by over 500%. Four walls were tested with eccentrically applied compressive loads to investigate bursting of the studs through the hemp-lime surface. On three walls the studs burst through the hemp-lime showing that bursting is dependent upon the hemp-lime cover over the studs. In addition unrestrained studs were tested and shown to buckle at much lower loads than the hemp-lime lime encapsulated studs. Under in-plane racking loads two walls were initially tested and found to have increased stiffness and strength over an unrestrained studwork frame. The leading stud joints were found to be a weak point. These joints were improved and two further walls were tested, one with a sheathing board attached to the studwork frame and one without. The strengthened joints were found to improve the stiffness and strength of the wall panels. The wall panel with sheathing was also found to have a higher stiffness than the unsheathed walls. Two walls were initially tested with applied out-of-plane loads. One wall was hemplime with rendered surfaces and the other included a studwork frame. The studwork frame was found to provide continued load capacity once the render and the hemp-lime had failed. Two further wall panels were tested with a sheathing board attached to the studwork frame and render on the other face of the hemp-lime. Again the studwork frames were found to provide post crack load capacity. The walls were also found to perform with differing stiffness according to the load direction. Following experimental testing the theoretical results were compared with the experimental results. Generally good correlation is seen between the results. Prior to the experimental testing it was not possible to predict the bursting of the hemp-lime when the studs were loaded in compression, however following testing a technique was developed to allow this prediction to be made. In conclusion this study has shown that hemp-lime does enhance the load capacity of studwork framing under both compressive and in-plane racking loads. Under out-ofplane bending loads the studwork frame allows continued load capacity after the hemplime and render have cracked. This study has shown that material savings can be made when using this type of construction as a sheathing board is not necessary as the hemplime can fulfil its structural function. This will contribute towards a more efficient construction system and reduced energy and resource use.
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Wretfors, Christer. "Hemp fibre and reinforcements of wheat gluten plastics /." Alnarp : Dept. of Agriculture - Farming Systems, Technology and Product Quality, Swedish University of Agricultural Sciences, 2008. http://epsilon.slu.se/11236319.pdf.
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Mills, Brantley. "On the use of dynamically similar experiments to evaluate the thermal performance of helium-cooled tungsten divertors." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52292.
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Many technological hurdles remain before a viable commercial magnetic fusion energy reactor can be constructed, including the development of plasma-facing components with long lifetimes that can survive the harsh environment inside a reactor. One such component, the divertor, which maintains the purity of the plasma by removing fusion byproducts from the reactor, must be able to accommodate very large incident heat fluxes of at least 10 MW/m^2 during normal operation. Modular helium-cooled tungsten divertors are one of the leading divertor designs for future commercial fusion reactors, and a number of different candidates have been proposed including the modular He-cooled divertor concept with pin array (HEMP), the modular He-cooled divertor concept with multiple-jet-cooling (HEMJ), and the helium-cooled flat plate (HCFP). These three designs typically operate with helium coolant inlet temperatures of 600 °C and inlet pressures of 10 MPa. Performing experiments at these conditions to evaluate the thermal performance of each design is both challenging and expensive.
An alternative, more economical approach for evaluating different designs exploits dynamic similarity. Here, geometrically similar mockups of a single divertor module are tested using coolants at lower temperatures and pressures. Dynamically similar experiments were performed on an HEMP-like divertor with helium and argon at inlet temperatures close to room temperature, inlet pressures below 1.4 MPa, and incident heat fluxes up to 2 MW/m^2. The results are used to predict the maximum heat flux that the divertor can accommodate, and the pumping power as a fraction of incident thermal power, for a given maximum tungsten temperature. A new nondimensional parameter, the thermal conductivity ratio, is introduced in the Nusselt number correlations which accounts for variations in the amount of conduction heat transfer through the walls of the divertor module. Numerical simulations of the HCFP divertor are performed to investigate how the thermal conductivity ratio affects predictions for the maximum heat flux obtained in previous studies. Finally, a helium loop is constructed and used to perform dynamically similar experiments on an HEMJ module at inlet temperatures as high as 300 °C, inlet pressures of 10 MPa, and incident heat fluxes as great as 4.9 MW/m^2. The correlations generated from this work can be used in system codes to determine optimal designs and operating conditions for a variety of fusion reactor designs.
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Anthireddy, Prasanna Kumar. "Development of a Natural Fiber Mat Plywood Composite." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1011815/.
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Natural fibers like kenaf, hemp, flax and sisal fiber are becoming alternatives to conventional petroleum fibers for many applications. One such applications is the use of Non-woven bio-fiber mats in the automobile and construction industries. Non-woven hemp fiber mats were used to manufacture plywood in order to optimize the plywood structure. Hemp fiber mats possess strong mechanical properties that comparable to synthetic fibers which include tensile strength and tensile modulus. This study focuses on the use of hemp fiber mat as a core layer in plywood sandwich composite. The optimization of fiber mat plywood was done by performing a three factor experiment. The three factors selected for this experiment were number of hemp mat layers in the core, mat treatment of the hemp mat, and the glue content in the core. From the analysis of all treatments it was determined that single hemp mat had the highest effect on improving the properties of the plywood structure.
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Khoathane, MC, OC Vorster, and ER Sadiku. "Hemp Fiber-Reinforced 1-Pentene/Polypropylene Copolymer: The Effect of Fiber Loading on the Mechanical and Thermal Characteristics of the Composites." SAGE, 2008. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000586.
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One of the recent developments in composite technology in South Africa is the increasing use of natural fiber materials in the manufacture of plastic products. Most of the previous
work on natural fiber-reinforced composites has focused on sisal fiber as it was commercially available. In this study, the mechanical and thermal properties of composites made with locally produced hemp fibers, were compared with composites made with hemp fibers produced in France.
New commercial polypropylene random copolymer was used as matrix because it can be processed at lower temperatures when compared with other commercial propylene copolymers. The composites were produced by extrusion compounding and were further processed into tensile test bars by injection molding. Up to 30% fiber loading could be achieved. It was observed in all composites that increasing the amount of fiber resulted in an increase in tensile strength, elastic
modulus, and flexural strength and a decrease in impact strength. The thermal properties of the composites were analyzed by the thermogravimetric method. It was found that the fiber/PP
composites showed excellent properties when compared to fiber and the matrix separately. The addition of hemp fibers shifted the start of the degradation process towards higher temperatures.
The results obtained show that the mechanical and thermal properties of South African long hemp fiber composites compare favorably well with the French bleached and unbleached hemp fibers.
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Ali, Arshad. "Surface modification of hemp fiber to improve spinning properties." AATCC, 2013. http://hdl.handle.net/1993/22053.
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Finer count hemp yarn (<20-50 tex) for apparel and smart textiles applications with a minimum number of imperfections cannot be manufactured using the cotton spinning system due to the presence of non-cellulosic materials in the fiber structure. An investigation has been carried out to identify the spinning properties of hemp fibers including strength, length and length variation, single fiber entity, fineness, bending modulus and softness by removing non-cellulosic materials from hemp. Different chemical and enzyme treatments were employed to improve the selected spinning properties of hemp fiber. It was found that bleaching at 95°C for 240 min (min) after scouring removed the largest amount of non-cellulosic materials. After the carding process, the softness of treated samples, with the highest weight loss (%) was found to be improved by about 2.6 times more than the virgin hemp fiber.
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Sam-Brew, Solace Araba. "The use of flax and hemp resource for particleboard." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/60617.
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The focus of this study was to investigate flax shive and hemp hurd as alternate residue for particleboard production, investigate the lowest percentage of the pricier polymeric diphenyl methane diisocyanate (pMDI) resin that can be used to effectively bond the residues and evaluate an acrylic-based resin for particleboard manufacture.
The flax shive and hemp hurd had lower bulk densities and higher aspect ratios compared with wood. Their higher aspect ratios offered greater overlap in bonding leading to consistently higher bending properties that exceeded American National Standards Institute (ANSI) requirements for low density (LD2) particleboard and in some cases, medium density (M2) particleboard. Because of their particle geometry, the flax shive and hemp hurd particleboards also showed minimal linear expansion with changes in moisture content between 50% and 90% relative humidity (at 20 ± 3°C) and were within ANSI requirements. The high absorption capacity of the residues resulted in higher thickness swell and water absorption properties in contrast to wood.
Improvements in bending strength above 40% and stiffness properties above 25% was achieved for wood, hemp hurd and flax shive particleboards by incorporating 15 weight % flax and hemp fiber in continuous mat form at the points of maximum tensile and compressive stresses in particleboard.
Test results confirmed the possibility of using 2.5% pMDI resin load, a percentage lower than the commercially viable 3%–6% addition levels that are commonly used with wood residues. The results further demonstrated that based on 2.5% pMDI resin load and as much as 20% mass lignin substitution boards with satisfactory mechanical properties that exceed LD2 grade requirements could be manufactured from hemp hurd and flax shive. Dynamic scanning calorimetry results and the current cost of the acrylic-based resin suggests that it is not suited for particleboard manufacture from flax shive and hemp hurd.
Overall, based on mechanical performance flax shive and hemp hurd residues can be considered as alternate biomass for particleboards of greater performance to wood for use in shelving and furniture applications. But the high cost of the residues compared to wood does not currently make it economical for particleboard manufacture.Forestry, Faculty of
Graduate
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Hirst, Edward A. J. "Characterisation of hemp-line as a composite building material." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636516.
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Hemp-lime is a comparatively novel renewable insulation material in the construction industry. Its use was first documented in the 1980’s, however, recent increased interest and the release of popular publications has resulted in an increased need for scientific investigation into the material. The research conducted in this investigation firstly focussed on furthering the empirical characterisation of hemp-lime and its constituents with particular attention paid to minimising fabrication variables and increasing the accuracy of final specimen bulk densities. Secondly attempts were made to quantify the degree of carbon sequestration that occurs as a result of the carbonation of the lime binder. A total of 196 specimens were fabricated for the main programme of work. It has been demonstrated that the novel fabrication methodology developed and tested in this investigation allows for reliable and consistent fabrication of specimens with almost identical final bulk densities. An average intrinsic empirical variability of 0.8% was determined for hemp-lime composites. It has been shown that the values of CO2 sequestration varied between 151- 192kg/m3 for the current formulated binders and composite bulk densities being used or considered in the UK construction industry. This resulted in a minimum 100% increase above the lowest estimated sequestration value from previous investigations. Preliminary carbonation constant values for hemp-lime have been determined, however, further testing is required to establish definite values based on a wider sample of testing.
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Quajai, Sirisart, and soj@kmitnb ac th. "Biopolymer Composite based on Natural and Derived Hemp Cellulose Fibres." RMIT University. Applied Sciences, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20061222.111612.
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The aim of this research was to study the effect of pre-treatment and modification processes on the properties of hemp cellulose fibre for biopolymer composites application. Hemp fibres have been modified by various extraction, swelling, chemical and enzymatic treatments. The morphology and mechanical properties of the modified fibres have been measured. Biopolymer composites have been prepared using the modified fibres and matrices of cellulose acetate butyrate and cellulose solutions derived from hemp. The first fibre treatment employed was acetone extraction and mercerization. A low pressure acrylonitrile grafting initiated by azo-bis-isobutylonitrile was performed using alkali treated fibre. The AN grafted fibres had no transformation of crystalline structure as observed after mercerization. The mechanical properties performed by a single fibre test method were strongly influenced by the cellulose structure, lateral index of crystallinity, and fraction of grafting. Bioscouring of hemp using pectate lyase (EC 4.2.2.2), Scourzyme L, was performed. Greater enzyme concentration and a longer treatment improved the removal of the low methoxy pectin component. Removal of pectate caused no crystalline transformation in the fibres, except for a slight decline in the X-ray crystalline order index. Smooth surfaces and separated fibres were evidence of successful treatment. The shortening of fibre by grinding and ball-milling was introduced to achieve a desired fibre size. An increase in the milling duration gradual ly destroyed the crystalline structure of the cellulose fibres. An increase in solvent polarity, solvent-fibre ratio, agitation speed and drying rate resulted in the rearrangement of the ball-milled cellulose crystalline structure to a greater order. The thermal degradation behaviour of hemp fibres was investigated by using TGA. The greater activation energy of treated hemp fibre compared with untreated fibre represented an increase in purity and improvement of structural order. The all hemp cellulose composites were prepared by an introduction of fibres into 12% cellulose N-methyl-morpholine N-oxide (NMMO) solution and water-ethanol regeneration. A broadening of the scattering of the main crystalline plane, (002) and a depression of the maximum degradation temperature of the fibres were observed. These revealed a structural change in the fibres arising from the preparation. The mechanical properties of composites depended on size, surface area, crystallinity and the structural swelling of the fibres. Composites of cellulose acetate butyrate (CAB) and modified hemp fibres were prepared. Composites containing pectate lyase enzyme treated fibres showed better mechanical property improvement than untreated and alkali treated fibres respectively.
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Sadek, Mohammad. "Modeling biofibre (hemp) processing using the discrete element method (DEM)." Food & Process Engineering Institute Division of ASABE, 2011. http://hdl.handle.net/1993/18484.
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The main objective of the research was to understand hemp processing at different stages through numerical simulations. Processing of hemp materials involves breaking the hemp into different sizes of particles and separating those particles into fractions of different sizes. Numerical models were developed using the discrete element method (DEM) to simulate hemp processing using a hammermill and separations of different hemp particles using a 3D vibratory screen-type separator. The models were implemented using a commercial DE code, the Particle Flow Code in Three Dimension (PFC3D). In the models, virtual hemp, hemp fibre and core were defined using clusters of PFC3D basic spherical particles which are connected by the PFC3D parallel bonds. The microproperties (e.g. particle stiffness and friction coefficient, and bond stiffness and strength) of these particles were calibrated. For calibrations, virtual tests were performed using PFC3D for hemp stem, fibre, and core. Those virtual tests included direct shear tests of fibre and core particles, tensile tests of fibre, and compression tests of hemp stems. The microproperties of these particles were calibrated through comparing results from the virtual tests with results from laboratory tests or literature data. Those calibrated particle microproperties were used in the PFC3D models developed for simulating the hammermill for hemp processing and the 3D vibratory separator for particle separation. These two machines were constructed using various PFC3D walls and lines, and had the main features and operational conditions as the real machines. The hammermill model was able to predict the power requirement of hammermill and particle dynamic behaviours (kinetic and strain energies) within the hammermill. The separator model was capable of predicting the separation efficiency of the 3D vibratory separator for separations of different hemp particle mixtures. The behaviour of the models reflected the real behaviour observed experimentally. The model results were reasonably good as compared with literature data and the test results. The models developed have the potential to simulate many other dynamic attributes of hemp particles with the machines. This study has laid a solid foundation for future studies of biomaterial-machine interactions using the DEM.
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Behr, Marc. "Molecular investigation of cell wall formation in hemp stem tissues." Doctoral thesis, Université catholique de Louvain, Louvain-la-Neuve, 2018. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/297325.
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The interest around hemp is currently renewed for the production of bio-based and renewable materials in the context of global warming. This fibre crop is able to produce large amounts of fibres with different features and industrial application. The most valuable fibres, found in the phloem tissue, are rich in cellulose while relatively poor in lignin, by contrast with the xylem tissue. This thesis aims at studying the events related to the biogenesis of these two types of fibre. Using two different systems, we will investigate the molecular mechanisms related toelongation, secondary growth, deposition and maturation of the cell wall and bast fibre development.Our first objective is to provide a comprehensive overview of the transcriptional factors and phytohormones involved in primary and secondary growth. To this end, the development of the hemp hypocotyl is investigated by a high throughput transcriptomic approach, in addition to proteomics, phytohormone and lignin analyses and microscopy. We show that elongation and secondary growth are characterised by specific patterns of gene expression. The consequences on the biogenesis and modification of the cell walls are widely discussed.The second objective is to decipher the molecular actors associated with the development of the bast fibres. We first show that the contrasting composition of xylem and bast fibres is regulated at the transcriptional level. Next, we highlight the evolution of the transcriptome during the development of the bast fibres, from intrusive growth to thickening. We put a special emphasis on the study of cell wall-related genes (cellulose synthase, fasciclin-like arabinogalactan, transcription factors) and phytohormones. We also formulate several hypotheses to explain the hypolignification of the bast fibres.Finally, this thesis ends with the perspectives raised by our results, notably concerning the deposition of cellulose, non-cellulosic polysaccharides and lignin in the bast fibres.info:eu-repo/semantics/nonPublished
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Hughes, John Mark. "On the mechanical properties of bast fibre reinforced thermosetting polymer matrix composites." Thesis, Bangor University, 2000. https://research.bangor.ac.uk/portal/en/theses/on-the-mechanical-properties-of-bast-fibre-reinforced-thermosetting-polymer-matrix-composites(0fdca4e4-8d50-4a16-afd0-37d78cfb8a64).html.
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Bast fibre reinforced, unsaturated polyester matrix composites were fabricated using non-woven mats of hemp or jute fibre as reinforcement. Composites were also prepared using chopped strand mat glass fibre as reinforcement. The short-term mechanical properties of the laminates were assessed. It was observed that at equivalent fibre volume fractions the stiffness of the glass fibre reinforced material only marginally exceeded that of the two, unmodified bast fibre, reinforced materials. At equivalent fibre volume fractions, however, the strength of the glass fibre reinforced composite was found to be significantly greater than that of the bast fibre reinforced materials. It was noted that in the bast fibre reinforced composites, the onset of non-linear behaviour occurred at relatively low applied stresses. Work of fracture in static three-point flexure and Charpy impact strength tests, indicated that the toughness of the plant fibre reinforced material was as much as an order of magnitude less than that of the glass fibre reinforced material. Fracture mechanics techniques were used to further quantify toughness and confirmed this to be so. Furthermore, these tests indicated that the microstructure of the bast fibre reinforced material should be examined more closely. Microscopy conducted on the fibres revealed that these were often subject to extensive micro-compressive damage. It was postulated that uneven fibre straining characteristics could lead to compromised interfacial properties, which might in turn detrimentally affect the macroscopic behaviour of the composite. A technique known as half fringe photoelasticity was used to investigate the stress-field in the matrix surrounding the fibre defects. It was observed that not only did concentrations of stress occur in the vicinity of these, but also that the shear stress distribution along the length of the fibre was interrupted by the presence of the defects. The implications of fibre defects upon composite properties are discussed.
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Anderson, Robert David. "Effects of Nitrogen Fertilizer Rate, Timing, and Herbicide Use on Industrial Hemp (Cannabis Sativa)." TopSCHOLAR®, 2018. https://digitalcommons.wku.edu/theses/2100.
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Industrial hemp (Cannabis sativa) is an old crop being reintroduced into certain states; thus, very little information is known about growing the crop domestically. Two field experiments were established in Bowling Green, KY to evaluate various nitrogen fertilizer rates and timing applications to examine the effects on growth and yield of industrial hemp (Cannabis sativa). Each experiment was sprayed with 1.12 a.i. ha-1 pendimethalin on half of each plot as a pre – emergent herbicide. Hemp was planted at a rate of 43 kg/ ha into a conventionally tilled silt loam soil. Nitrogen rates studied were a control, 79, 157, and 236 kg N/ ha in the first experiment. In the second experiment, 157 kg N/ ha was applied at three timings along with a control. The three timings were: at establishment, side-dressed, and a split application of 78 kg at establishment and 78 kg side dressed. Plots were 6 m x 4.5 m and replicated 4 times for each experiment.
Data collected included stand counts 34 days after planting (DAP), plant heights at 34 and 55 DAP, and stand counts, plant heights, fresh biomass, dried biomass, seed yield, and fiber yield at harvest (89 DAP) for both experiments. Increased fertilizer rates increased fresh and dried biomass which correlated with increased fiber yields. Different fertilizer timings had no effect on seed, biomass, or fiber yields. Herbicide had an early effect on stand counts and plant height in both experiments (
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Byrd, Jabari Akil. "Industrial Hemp (Cannabis sativa L.) Germination Temperatures and Herbicide Tolerance Screening." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/91431.
Full textAbstract:
Industrial hemp (Cannabis sativa L.) has a long history of human use. Early in the 20th century, some predicted hemp would be the first billion dollar crop given its multiple industrial applications. Government policy that restricted, then prohibited, hemp's use in the U.S. prevented that from happening. A reawakening to the versatility and usefulness of hemp for products ranging from engineering fibers and textiles to food and health products has developed over the last 30 years. Hemp-based products are thriving on the market for public demand. In Virginia, passage of legislation in 2017 made hemp a legal cash crop. Appropriate management decisions rely on information available from researchers. However, very few data on hemp production are available for this region. Hemp varieties may differ in part due to the broad range of latitude associated with their source of origin (e.g., from Italy to Finland in Europe) and thus the plant's differential responses to light and temperature regimes. Thus, a factor such as varietal response to soil temperature at germination could be an important variable for successful establishment, which is critical to crop productivity. Stand establishment, in turn, may be affected by factors such as germination temperature, which has implications for planting date.
Along with establishment, few data have been published regarding hemp's tolerance to different herbicides. To date, the only published studies from the Southern region of the United States regarding hemp production in response to herbicide treatments were conducted in Kentucky. Generating basic information on hemp response to temperature for germination and tolerance to herbicides will be important step for developing a suite of useful agronomic practices that support the incorporation of hemp into Virginia cropping systems. The hemp industry's development in Virginia is still in its early stages, and the research described here focused on questions related to germination temperature and herbicide tolerance will help to improve our understanding of and determine suitable agronomic practices for the crop We thus designed experiments to test the following null hypotheses: Industrial hemp will not differ in germination response to temperatures, regardless of source of origin. Industrial hemp will not differ in measures of visible injury, yield, and growth in response to preemergent or postemergent herbicide treatments.Master of Science
Industrial hemp (Cannabis sativa L.) has a long history of human use. Early in the 20th century, some predicted hemp would be the first billion dollar crop given its multiple industrial applications. Government policy that restricted, then prohibited, hemp’s use in the U.S. prevented that from happening. A reawakening to the versatility and usefulness of hemp for products ranging from engineering fibers and textiles to food and health products has developed over the last 30 years. Hemp-based products are thriving on the market for public demand. In Virginia, passage of legislation in 2017 made hemp a legal cash crop. Appropriate management decisions rely on information available from researchers. However, very few data on hemp production are available for this region. Hemp varieties may differ in part due to the broad range of latitude associated with their source of origin (e.g., from Italy to Finland in Europe) and thus the plant’s differential responses to light and temperature regimes. Thus, a factor such as varietal response to soil temperature at germination could be an important variable for successful establishment, which is critical to crop productivity. Stand establishment, in turn, may be affected by factors such as germination temperature, which has implications for planting date. Along with establishment, few data have been published regarding hemp’s tolerance to different herbicides. To date, the only published studies from the Southern region of the United States regarding hemp production in response to herbicide treatments were conducted in Kentucky. Generating basic information on hemp response to temperature for germination and tolerance to herbicides will be important step for developing a suite of useful agronomic practices that support the incorporation of hemp into Virginia cropping systems. The hemp industry’s development in Virginia is still in its early stages, and the research described here – focused on questions related to germination temperature and herbicide tolerance – will help to improve our understanding of and determine suitable agronomic practices for the crop We thus designed experiments to test the following null hypotheses: Industrial hemp will not differ in germination response to temperatures, regardless of source of origin. Industrial hemp will not differ in measures of visible injury, yield, and growth in response to preemergent or postemergent herbicide treatments.
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Latif, Eshrar. "Hygrothermal performance of hemp based thermal insulation materials in the UK." Thesis, University of East London, 2013. http://roar.uel.ac.uk/3454/.
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This thesis explores the hygrothermal performance of hemp insulation in the context of the United Kingdom. The key objectives of this investigation were to assess the heat and moisture management capacities of hemp insulations in two constructions typical to the UK, of timber frame and solid brick walls and to put the findings of the assessment into the greater context of conventional insulation materials by comparing hemp insulation’s performance with that of stone wool. The assessments were performed by means of laboratory-based experiments, in situ experimental monitoring and computer based numerical hygrothermal simulations. The most important finding during the laboratory-based experiment is that, in high relative humidity, the likelihood and frequency of interstitial condensation is higher in stone wool insulation than in hemp insulation. In terms of the material properties, one of the key findings during the laboratory-based experiment is the high level of moisture buffering capacities of hemp insulations, and therefore their potential in managing moisture in buildings. The in situ assessment of hygrothermal properties of hemp and stone wool insulations confirms the findings of the laboratory based experiments of the corresponding moisture management capacities of these two insulation materials. Parametric analysis of the in situ data shows that mould spore germination is possible in the insulations in vapour open walls although the visual observation has not confirmed the outcome of this analysis. In terms of thermal conductivity, the important finding is that the equivalent thermal conductivity of hemp and stone wool insulations are always equal or below the manufacturers’ declared thermal conductivity values. Long-term hygrothermal performances of hemp and stone wool insulation in timber frame and solid brick walls have been also assessed using a numerical hygrothermal simulation tool (WUFI). As far as the WUFI predictions are concerned, the application of the hemp or stone wool insulation on solid brick wall does not seem to be feasible with reference to condensation and mould growth in the insulations.
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Truedsson, Herman, and Henrik Jacobsson. "Prefabricerade väggelement av hampabetong." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-24395.
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Lime Hempcrete consists of lime, water and hemp and creates an insulating, sound-absorbing, lightweight and environmentally friendly material that can be used in wall, roof and floor structures (Bevan & Woolley 2008). This construction method is not yet developed in Sweden as there has been a ban on the cultivation of the hemp plant. This ban on the cultivation of hemp was removed in 2003, when the material got a boost. You can use it in many different ways and not just in the construction industry (Ahlsten, 2010). In this study we have investigated the possibility to produce prefabricated wall elements of LHC. We have also studied its mechanical properties and dehydration time. Different types of mixes were made to find out which type of blend that worked best and had good workability properties. Four different types of wall elements were made to see how they react when they are handled and lifted and to show how you can connect the wall elements to each other and how you can connect them in corners.
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McLaggan, Martyn Scott. "Novel fire testing frameworks for Phase Change Materials and hemp-lime insulation." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/15896.
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Modern buildings increasingly include the usage of innovative materials aimed at improving sustainability and reducing the carbon footprint of the built environment. Phase Change Materials (PCMs) are one such group of novel materials which reduce building energy consumption. These materials are typically flammable and contained within wall linings yet there has been no detailed assessment of their fire performance. Current standard fire test methods provide means to compare similar materials but do not deliver knowledge on how they would behave in the event of a real fire. Thus, the aim of this thesis is to develop a novel testing framework to assess the behaviour of these materials in realistic fire scenarios. For PCMs, a flammability study is conducted in the bench-scale cone calorimeter to evaluate the fire risk associated with these materials. Then, micro-scale Thermogravimetric Analysis (TGA) is used to identify the fundamental chemical reactions to be able to confidently interpret the flammability results. Finally, intermediate-scale standard fire tests are conducted to evaluate the applicability of the bench-scale results to realistic fire scenarios. These take the form of modified Lateral Ignition and Flame spread Test (LIFT) and Single Burning Item (SBI) tests to understand flame spread and compartment fires respectively. Finally, a simplified method to combine this knowledge for use in building design is proposed. This method allows the balancing of potential energy benefits with quantified fire performance to achieve the specified goals of the designer. Hemp-lime insulation is a material which has also becoming increasingly popular in the drive towards sustainability. The porous nature of the material means that smouldering combustions are the dominant reaction mode but there is currently no standardised test method for this type of behaviour. Thus, hemp-lime materials also represent an unquantified risk. The work in this thesis defines a simple, accessible and economically viable bench-scale method for quantifying the fire risk associated with rigid porous materials. This is applicable for both downward opposed flow and upward forward flow smoulder propagation conditions. The behaviour is then interpreted using micro-scale thermogravimetric analysis to understand the underlying pyrolysis and oxidation reactions. Designers can utilise this framework to quantify the smouldering risk associated with hemp-lime materials to enable their usage in the built environment. The holistic fire risk assessment performed in this thesis has quantified the behaviour of PCMs and hemp-lime insulation applicable to realistic fire scenarios. The simplified design method empowers designers to be able to realise innovative buildings through fundamental understanding of the fire behaviour of these materials. The outcomes of this thesis allow designers to mitigate the fire risk associated with these materials and achieve optimised engineering solutions. Furthermore, the novel fire testing frameworks provide the economically viable means to assess the fire performance of future PCMs and hemp-lime products which ensures lasting relevance of this research in the future.
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Francis, Sara K. "Hemp, Cannabis sativa L., as an alternative fibre source for Nova Scotia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq24965.pdf.
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Correia, Fatima M. C. "Fibre characteristics and chemical pulping of Canadian industrial hemp (Cannabis sativa L.)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ45604.pdf.
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Malomo, Sunday. "Structure-function properties of hemp seed proteins and protein-derived acetylcholinesterase-inhibitory peptides." Elsevier, 2014. http://hdl.handle.net/1993/30736.
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Hemp seed proteins (HSP) were investigated for physicochemical and functional properties in model food systems. In addition, the HSP were enzymatically digested and the released peptides investigated as potential therapeutic agents. Membrane isolated HSP (mHPC) were the most soluble with >60% solubility at pH 3-9 when compared to a maximum of 27% for isoelectric pH-precipitated proteins (iHPI). However, iHPI formed emulsions with smaller oil droplet sizes (<1 µm) while mHPI formed bigger oil droplets. The iHPI was subjected to enzymatic hydrolysis using different concentrations (1-4%) of six proteases (pepsin, pancreatin, flavourzyme, thermoase, papain and alcalase) to produce various HSP hydrolysates (HPHs). HPHs had strong in vitro inhibitions of angiotensin converting enzyme (ACE) and renin activities, the two main enzyme systems involved in hypertension. Oral administration of the HPHs to spontaneously hypertensive rats led to fast and persistent reductions in systolic blood pressure. The HPHs also inhibited in vitro activities of acetylcholinesterase (AChE), a serine hydrolase whose excessive activities lead to inadequate level of the cholinergic neurotransmitter, acetylcholine (ACh). Inadequate ACh level in the brain has been linked to neurodegenerative diseases such as dementia and Alzheimer’s disease (AD); therefore, AChE inhibition is a therapeutic target. The 1% pepsin HPH was the most active with up to 54% AChE inhibition at 10 µg/mL peptide concentration. The 1% pepsin HPH (dominated by <1 kDa) was subjected to reverse-phase HPLC peptide purification coupled with tandem mass spectrometry, which led to identification of several peptide sequences. Some of the peptides inhibited activities of both animal and human AChE forms with LYV being the most potent against human AChE (IC50 = 7 µg/ml). Thus the LYV peptide may serve as a useful template for the development of future potent AChE-inhibitory peptidomimetics. In conclusion, several novel AChE-inhibitory peptides were discovered and their amino acid sequences elucidated for the first time. Results from this work identified HSP products that could serve as functional ingredients in the food industry. The work also produced and confirmed the in vitro AChE-inhibitory activities of several new peptide sequences that may serve as therapeutic agents for AD management.October 2015
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Kohútová, Darina. "Komplexní zpracování technického konopí a využití izolovaných frakcí." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449746.
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Hemp is a plant containing many active substances and it is widely used in industry. The most common applications are the food, pharmaceutical, textile and cosmetics industries. This diploma thesis dealt with the characterization of hemp fractions, which are created during hemp processing and their potential applications. The theoretical part was focused on the description of the plant, its chemical composition and the research of the active substances in hemp. Also, its industrial use, the technique of hemp processing and the current applications of individual fractions were summarized. In the experimental part, hemp fractions were analysed in terms of nutrient content. Hemp extracts were prepared using three solvents - hexane, 70% ethanol and distilled water, which were compared based on the extraction yield of polyphenols, flavonoids, antioxidants, chlorophylls and cannabinoids. Antimicrobial effects were analysed in hexane and ethanol extracts. By-products of hemp processing were used in some screening application in biotechnology, cosmetics and nutrition. The results show that the extract with 70% ethanol had the highest content of active substances. From the hemp fractions, hemp trichomes and Fedora flowers had the highest content of active substances. Cannabis by-products have the potential to become valuable substrates for yeast cultivation. Face scrub containing hemp flour as an abrasive component had favourable results and was acceptable to consumers, as was the prepared hemp flour raw bar, which was evaluated to be comparable to commercially available hemp protein raw bars.
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Ehresmann, Michael John. "A Study on the Processing Characteristics and Reinforcing Potential of Natural Fiber Mats." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26638.
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Limited information exists regarding the processing parameters and extent of reinforcing potential natural fibers have in polymer matrices. The five natural fiber mats studied were low shive flax, mid shive flax, high shive flax, hemp and kenaf. The parameters characterized were fiber size, wax content, surface contact angle, and shive content. The compressive force and unsaturated permeability was measured for each mat, and composites were constructed and tested using selected mats in a soy-based polyurethane (PU) matrix. All mats exhibited a viscoelastic behavior under compression, and an increase in shive content correlated with an increase in relaxation. The presence of shive and larger fiber size increased the permeability. Higher wax content and contact angle lowered the permeability. The mechanical properties for all composites performed better than the neat PU, showing there was matrix to fiber adhesion and load transfer. Hemp outperformed the other fibers studied in all mechanical tests.
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Maxwell, Brett A. "Effects of Herbicides on Industrial Hemp (Cannabis Sativa) Phytotoxicity, Biomass, and Seed Yield." TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1742.
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Field studies were established in 2015 at Bowling Green and Lexington, KY to evaluate industrial hemp (Cannabis sativa) tolerance to various herbicides. Hemp was planted into conventionally tilled soils in mid to late June at a seeding rate of 39 kg/ha in Bowling Green and 22 kg/ha in Lexington. Five herbicide active ingredients were applied preemergence (PRE) the day of planting and six postemergence (POST) treatments were applied to 30 cm hemp with a CO2-backpack sprayer delivering 140 L/ha. Plots were 3.1 m wide by 6.1 m long and were sprayed with a 2.1 m boom sprayer leaving a 0.46 m visual check on either side of the sprayed area. A weed free check and a non-treated control were included and all treatments were replicated four times in a randomized complete block design.
Hemp phytotoxicity was evaluated at 14 days after treatment for both PREs and POSTs. Hemp above-ground biomass, weed above-ground biomass, and seed yield were also evaluated. PRE herbicides did not injure hemp as much as POST herbicides, especially at the Bowling Green location. Mesotrione was the most injurious PRE evaluated (> 90%) while bromoxynil and MSMA applications resulted in low phytotoxicity (< 15%). Above-ground biomass was higher in the PRE treated plots, with the exceptions of bromoxynil and MSMA. Weed above-ground biomass was higher in the POST treated plots with the exception of mesotrione. At Bowling Green, PRE herbicides resulted in comparable yields to the weed-free check, except mesotrione. Metolachlor increased seed yield compared to the weed-free check and MSMA and bromoxynil had comparable yields to the weed-free check at both locations. Results identified possible herbicides to include in a future integrated pest management weed control program for industrial hemp.
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Han, Hongchang. "Study of agro-composite hemp/polypropylene : treatment of fibers, morphological and mechanical characterization." Thesis, Troyes, 2015. http://www.theses.fr/2015TROY0002/document.
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L’utilisation des fibres végétales dans les polymères composites suscite de nombreuses investigations. Avant de mélanger les fibres végétales dans le polymère, un traitement chimique peut être effectué permettant de réduire l’hydrophilicité des fibres et d’améliorer l'adhérence à l’interface fibre/matrice. Dans cette thèse, l'eau et l'alcali sont utilisés d'abord pour traiter les fibres de chanvre, puis trois agents silane : 3-(triméthoxysilyl)propyl méthacrylate (MPS), N-[3- (triméthoxysilyl)propyl] aniline (PAPS) et (3-Aminopropyl)-triéthoxysilane (APS), sont utilisés pour modifier plus ou moins la surface des fibres de chanvre. Ces fibres traitées ou modifiées sont ensuite mélangées avec le polypropylène (PP) pour la fabrication des composites. Les effets de ces différents traitements sur la structure, les composants et l’hydrophilicité des fibres, et les propriétés mécaniques de ces composites sont mis en évidence. Nous avons étudié ensuite l’effet de vieillissement sur leurs comportements mécaniques, notamment l'humidité, la température et le rayonnement ultraviolet. Les résultats ont montré que le traitement de fibres par l'eau et l’alcali a des effets considérables sur la structure de fibres, les propriétés mécaniques et la durabilité des composites renforcés. La modification par l'agent de silane a une influence moins importante sur la structure des fibres, pourtant son groupe fonctionnel a une influence significative sur les propriétés mécaniques et la résistance au vieillissement des composites renforcésUsing agro fiber as reinforcement of polymer com-posites attracts numerous investigations due to the good mechanical properties and environmental benefits. Prior to blend agro fiber with polymer, chemical treatment can be employed to treat agro fiber for the purpose of reducing the hydrophilicity of fiber and improving the interfacial adhesion fi-ber/polymer matrix. In this thesis, water and alkali are utilized to treat hemp fiber firstly and then three silane agent as 3-(Trimethoxysilyl)propyl methacry-late (MPS), N-[3-(Trimethoxysilyl)propyl]aniline (PAPS) and (3-Aminopropyl)-triethoxysilane (APS) are employed to modify the hemp fiber surface. These treated or modified fibers are blended respectively with polypropylene (PP) to fabricate the hemp fiber/PP composites. The effects of these different treatments on the structure, components and hydro-philicity of fiber, and the mechanical properties of the reinforced PP composites are studied. Moreover, the accelerated ageing experiments including humidity, temperature and ultraviolet of the reinforced PP composites are conducted. The results showed that the fiber treatment of water and alkali has a considerable effect on fiber structure, mechanical properties and durability of the reinforced compo-sites. The silane agent modification of fiber has less influence on the fiber structure but its functional group has great influence on the mechanical proper-ties and ageing resistance of the reinforced compo-sites
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Case, Olivia Hildegard. "An assessment of medicinal hemp plant extracts as natural antibiotic and immune modulation phytotherapies." Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
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This study aimed to evaluate the antimicrobial efficacy of medicinal hemp plant extracts to determine the antibacterial effects of indigenous Sansevieria species and exotic Cannabis sativa phytotherapy varieties. This study also assessed whether aqueous o
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Blouw, Langa Sunshine. "Effect of cultivar on the quality of flax and hemp grown in South Africa." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1010997.
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Bast fibrous renewable materials, as commercial crops for the manufacture of textile based and other products, have been used for thousands of years to satisfy certain human needs, such as for shelter, clothing, source of energy and tools, and to sustain the livelihood of many communities in countries, such as in Asia, Europe and Africa. Concern for the environment has led to a number of global initiatives that favour the use of natural fibres. It is forecast that the global fibre demand by 2050 will be 130 million tonnes, which the cotton and synthetic fibre production will not be able to meet. Other than the environmental concerns, the renewed global interest in natural fibres, such as flax and hemp, forms part of a strategy to satisfy the fibre demand. South Africa, notwithstanding the fact that the flax and hemp industries have long been established for thousands of years in Europe, Asia and Egypt (Africa), has no history of the breeding, growing, processing and production of these cash crops. The renewed global interest in these crops has also stimulated interest from South Africa with respect to the development of a flax and hemp fibre industry so as to address some of the socio-economic challenges confronting the country today in its attempts to bring about real development in the rural areas through the cultivation and complete beneficiation of these fibre crops. In this regard, the relevant stakeholders, namely government, research councils, tertiary education institutions, farmers and communities worked together to investigate whether South Africa has the agronomic and climatic conditions, technical expertise as well as the necessary processing and production infrastructure to support the development of a local flax and hemp agro-industry. The purpose of this study was firstly to evaluate the performance of EU flax and hemp cultivars grown under different agronomic conditions in South Africa, and their effect on straw biomass yield, fibre yield and total fibre yield per hectare as well as associated fibre properties, and secondly to undertake mechanical fibre modification trials aimed at producing flax and hemp fibres with fibre diameters close to those of cotton. The minimum fibre diameter targeted being 20μm. In accordance with the project objectives and work plan, selected dew retted flax and hemp straw samples from the various planting sites selected by the Agriculture Research Council – Institute for Industrial Crops, representing all the agronomic conditions under investigation, were taken to the CSIR for fibre extraction and testing. A relatively inexpensive and easy to operate Russian designed and manufactured machine, the CMT-200M breaker-cum-scutcher, was used for fibre extraction and the resultant extracted fibre bundles were further refined, using a steel comb, to obtain optimal fibre separation before their physical and chemical properties were evaluated. Results obtained in this research study proved that the climatic and agronomic conditions in South Africa were suitable for the cultivation of flax and hemp, notwithstanding the fact that the fibre yields achieved for hemp were lower than the minimum criteria of 23 percent, and that for flax only just exceeded the 25 percent minimum. The lack of local technical expertise on the growing and retting of flax and hemp, contributed to the low fibre yields. The planting parameters which were found to produce good results for the cultivation of hemp were the October planting date, using a row spacing of between 12.5 to 25 cm, with a seeding density of between 80 – 100kg, and the application of 50 – 100kg nitrogen fertiliser. The use of extra artificial lighting and herbicide treatment did not appear to beneficially improve the hemp fibre yields. Similar considerations for flax cultivation in the Southern Cape region, particularly Oudtshoorn and Outeniqua, indicated that May to July planting dates, using inter-row spacing of 25cm and sowing density of 63kg seed.haˉ¹, produced a fibre yield and total fibre yield per hectare above the minimum values of 25 percent and 0,8 tonnes per hectare, respectively, quoted in the literature.
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Gadoury, Hélène. "Evaluation of Septoria galeopsidis Westd. as a bioherbicide for hemp-nettle (Galeopsis tetrahit L.)." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61896.
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Vermeulen, John Franciscus. "From the grave to the cradle :exploration of hemp as an eco-design material." Thesis, Cape Peninsula University of Technology, 2008. http://hdl.handle.net/20.500.11838/1316.
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Thesis (MTech (Design))--Cape Peninsula University of Technology, 2008This thesis argues that the story of hemp is one of mistaken identity and focuses on the potential of hemp (Cannabis sativa L.) in a social and economic context. It also asserts how hemp with the application of appropriate technologies can be developed nationally 'new' material, with reference to examples from abroad. The current proliferation of raw material shortages means that designers have a social responsibility to seek new ways to source and process materials for a sustainable future. Designers are the "future creators" and should prescribe materials that are not only healthy in the cycle of production, but also ensure an afterlife (recycling). The methodology employed is a combination of qualitative (such as interviews) and quantitative methods (such as statistical analysis). Life Cycle Analysis is used to study the ecological impact of substituting hemp for current materials and processes. The study interrogates the historic significance of hemp in various societies across the world with particular focus on Europe, Japan, the United States of America, Ireland and Australia. Such information is analysed within the realities of the South African context. A vast amount of information on hemp has been published but practical information is hard to obtain in South Africa necessitating a search for definite answers abroad, mainly in Europe where there is a strong development in this field. After researching the production of the hemp raw materials and the manufacture of viable hemp products abroad, lessons could be assessed for application to the local market. The findings endorse the view that hemp is a sustainable zero-waste material; the whole plant can be used when harvested, which makes it an ideal material on which to base an eco-design system. Hemp can be processed by utilizing either high technology equipment or by the use of locally available equipment and manual labour. It can be converted into a multi-diverse range of viable products such as paper, thatching, building material and ceiling panels. The main reason for the isolation of hemp in South Africa is the mistaken assumption that it is a drug and outlawed by our legislation. Since hemp (Cannabis sativa L) is perceived as a vilified cousin of marihuana it has lead to a blanket ban on both plants. This is certainly not warranted as hemp produces an extremely low value of the controversial hallucinogenic tetrahydrocannabinol (THC)properties which is negligible.
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Zhang, Xiaohui. "Manufacturing of hemp/PP composites and study of its residual stress and aging behavior." Thesis, Troyes, 2016. http://www.theses.fr/2016TROY0015/document.
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Depuis quelques années les matériaux composites à base de fibres naturelles sont de plus en plus utilisés pour les nouvelles performances qu’ils proposent. C’est surtout au niveau des fibres naturelles que de nouvelles propriétés sont proposées. Dans ce travail, nous nous sommes essentiellement intéressés aux fibres naturelles de chanvre. Ces fibres sont déjà fortement utilisées dans l’automobile et la construction. En Europe, ces fibres sont produites principalement en France et plus particulièrement dans l’Aube. Pour développer des agro-composites hautes performances, c’est sous la forme de fibres longues et de tissus que nous avons choisi d’orienter ce travail de thèse. Nous avons choisi la thermocompression pour élaborer des plaques avec des tissus de chanvre et une matrice en polypropylène (PP). Ce travail permet de voir l’influence des conditions d’élaboration sur le comportement mécaniques de ces agro-composites. Cette thèse permet aussi de voir l’effet du vieillissement aux UV et à l’Humidité sur les performances de ces matériaux. Enfin une analyse des contraintes résiduelles par la méthode du trou incrémental permet de voir leurs effets sur ces agro-matériauxIn recent years composite materials based on natural fibers are more and more used for their new performances. Natural fibers propose attractive environmental, mechanical and thermal properties.In this work, we are firstly interested in hemp fibers. These fibers are already used in the automotive and construction industry. In Europe, these fibers are produced mainly in France and especially in Aube. To develop agro-composites with high performances, we have focused this thesis on hemp woven. We chose to elaborate the plates with hemp woven and a polypropylene matrix (PP) by compression molding. This work allows us to see the influence of elaboration conditions on the mechanical behavior of these agro-composites. This thesis also allows us to see the effect of aging conditions UV and humidity on the performance of these materials. Finally an analysis of residual stresses determined by the hole drilling method is proposed to see their effects on the agro-materials
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De, Prato Luca. "Genotype by environment interactions of industrial hemp (Cannabis sativa L.) varieties under tropical conditions." Thesis, De Prato, Luca (2021) Genotype by environment interactions of industrial hemp (Cannabis sativa L.) varieties under tropical conditions. PhD thesis, Murdoch University, 2021. https://researchrepository.murdoch.edu.au/id/eprint/61031/.
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Christmas Island, Australia, is a remote tropical island that relies predominantly on phosphate mining income. Given that mining operations will decline during the next decade, there is an urgent need to explore alternative industries to maintain local employment. This need could be met through activities such as a transition from mining to the production of high-value crops established in post-mined quarries. However, agriculture post-mining presents a series of challenges to growing crops, such as the lack of appropriate nutrients and organic matter, and the potential for soil compaction and the presence of heavy metals.
Industrial hemp (Cannabis sativa L.) grows well in contaminated substrates, making it an ideal candidate for evaluation in the transition from mining to agriculture on Christmas Island. Hemp is a crop gaining increasing attention due to its wide range of commercial products and the relaxing of legal restrictions associated with its secondary metabolites.
Preliminary experiments with hemp on Christmas Island identified a range of challenges to plant growth, such as the early onset of flowering, stunted growth, nutrient deficiency symptoms, low yield, and fluctuations in cannabinoid concentrations. Although some research has been carried out on hemp globally, there is limited information on optimal conditions for flowering, growth and nutrition, and cannabinoid production under tropical/subtropical environmental conditions. The current study examined a range of hemp varieties in terms of time to flowering, growth, biomass and seed yields, as well as cannabinoid production, in response to a series of abiotic stressors present under the tropical conditions of Christmas Island in postphosphate mined soil.
Before undertaking these experiments, an improved method for extraction and detection of cannabinoids was developed. Following this, to investigate the challenges associated with growing hemp on Christmas Island, selected tropical/subtropical varieties (ECO-GH15, ECO-MC16 and ECO-YP16), bred by Ecofibre Limited, and the temperate hemp variety (Morphet Late) were evaluated under different daylengths, temperatures, nutrition and heavy metal substrate concentrations, in controlled growth rooms, to determine physiological, cannabinoids and growth responses.
The combination of daylength and temperature affected time to flowering, and consequently, final biomass. Under short daylength (11.5 h and 12.5 h), temperature was shown to be the main driver for time to flowering, depending on genotype. Cannabinoid concentrations were affected by one extra hour of daylength, and varieties responded differently. These experiments revealed the responses of diverse ecotypes and the importance of environment by genotype interactions.
Soil nutrient content impacted time to flowering, photosynthesis, leaf gas exchange and plant growth, resulting in significant differences in biomass, seed and cannabinoid production. The addition of nitrogen was associated with higher above ground biomass. Plants not receiving nitrogen had greatly diminished development and growth. Phosphate deficiency delayed time to flowering and flower development. Increasing phosphate concentrations and slow-release fertiliser application increased net photosynthesis under high photosynthetically active radiation (1800 μmol m-2s-1). Potassium deficiency resulted in increased stomatal conductance and gas exchange, possibly due to impaired stomatal function. The investigation of potential cadmium uptake confirmed that hemp could grow in soils containing cadmium and that the plants limit its translocation to leaves and seeds with increasing cadmium concentration in the soil.
Overall, this work demonstrates the importance of genotype by environment studies to identify appropriate ecotypes and optimal plant nutrition to achieve consistent production from hemp in tropical/subtropical conditions. The results of this study contribute to our understanding of hemp production in terms of time to flowering, cannabinoid production, and physiology while providing a potential economic opportunity for Christmas Island. These findings could also inform other remote communities at similar latitudes with post-mining soils regarding the requirements for growing hemp as a high-value crop. Remote communities could take advantage of multipurpose applications of hemp as a viable option for high-value products. Knowledge of hemp cannabinoid production as affected by the environment will be essential, globally, to tailor cannabinoids for particular needs.
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Tura, Matilde <1994>. "Instrumental and sensory analyses for the characterization of food, phytotherapeutic or pharmaceutical hemp products." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10097/1/Thesis%20Matilde%20Tura.pdf.
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To address the request to develop rapid and easy methods for determining the cannabinoids, an HPLC-UV method (8 min) to separate and quantify the 10 main cannabinoids in hemp inflorescences was developed, and in-house validated. Moreover, the antioxidant activity of cannabidiol (CBD) in two oily matrices was investigated and compared to that of α-tocopherol, in relation to the growing market of oily solutions containing cannabidiol. Then, since no univocal legislation on the evaluation of quality and authenticity of hemp seed oil (HSO) exists, the composition and quality of cold-pressed HSOs were also explored, highlighting a great variability in terms of oxidative state minor compounds content. From the sensory point of view, a panel was trained, a specific sensory wheel and a profile sheet were developed. Due to the Covid-19 pandemic, the sensory evaluation was also performed at home. The panel showed a good performance both in the laboratory and remotely. Moreover, a focus group was used to investigate consumers’ attitudes, pointing out that a high-quality HSO has to be cold-pressed and green for them. Then, the evaluation of stability during the storage of HSOs was investigated. The results showed that photo-oxidation did not seem to significantly affect the quality of the oil during the first 3 months of storage. Finally, a study about the evolution of the volatile profile of 9 HSOs, under accelerated oxidation conditions, allowed identifying volatile markers of HSOs oxidation and freshness.
This Ph.D. was developed in the context of the scholarship “Harmonized procedures of analysis of medical, herbal, food and industrial cannabis: development and validation of cannabinoids’ quality control methods, of extraction and preparation of derivatives from the plant raw material, according to the product destination” funded by Enecta S.r.l.
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Fourmentin, Marine. "Impact de la répartition et des transferts d'eau sur les propriétés des matériaux de construction à base de chaux formulées." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1100/document.
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Le béton de chanvre est obtenu par le mélange d'un granulat végétal, constitué de bois de chanvre, et d'un liant. Il confère au mur de bonnes propriétés d'isolation thermique et acoustique, ainsi qu'une régulation de l'humidité. Cependant, des problèmes de non-prise, qui semblent fortement liés aux transferts d'eau dans le béton au cours des premières heures, peuvent parfois se produire. La RMN permet de quantifier l'eau dans le chanvre et dans le liant et donc de décrire et comprendre les transferts au cours de la prise. Nous montrons d'abord que, dans le liant constitué d'un mélange de chaux hydraté et de ciment, la chaux accélère la prise du ciment. Cette prise est d'autant plus inhibée que la quantité de chanvre au contact du ciment est importante. Nous montrons également que l'absorption d'eau par le granulat de chanvre s'étale sur trois jours, et qu'elle se produit en deux phases successives correspondant à l'imprégnation de deux zones du chanvre. L'étude des transferts dans le béton pendant la prise révèle une absorption d'eau rapide par le chanvre initialement, puis un transfert vers le liant. L'étude d'un béton de chanvre "modèle" nous permet d'associer ce transfert au retrait chimique du ciment au cours de la priseHemp concrete results from the mix of a vegetal aggregate (hemp shives) and a binder. It provides thermal and acoustic insulation to the wall, as well as a good moisture regulation. However, problems sometimes occur during setting, that seem strongly linked to transfers of water in the concrete in the first hours. NMR allows to quantify water in hemp and in the binder and thus to describe and understand the transfers during setting. We first show that, in the binder consisting of a mixture of hydrated lime and cement, lime accelerates cement hydration. This hydration is inhibited as the amount of hemp in contact with the cement increases. We also show that the absorption of water by hemp shives is takes place during three days, and it occurs in two successive phases corresponding to two areas of hemp that imbibe. The study of transfers in the concrete during the setting shows a rapid water absorption by the hemp initially, followed by a transfer to the binder. The study of a "model" hemp concrete allows us to associate this transfer to the chemical shrinkage of cement during hydration
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Antony, Sheedev. "Multiscale Analysis to Investigate the Mechanical and Thermoforming Behaviour of Hemp Fibre Based Agro-composite." Electronic Thesis or Diss., Troyes, 2019. http://www.theses.fr/2019TROY0026.
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Ces dernières années, les fibres naturelles de chanvre affichent un grand potentiel d’application dans les secteurs de l’aérospatiale et de l’automobile en raison de leur recyclabilité, renouvelabilité et biodégradabilité. Associés à une matrice polymère, les tissés à base de fibres végétales permettent l’élaboration des pièces structurelles bio-sourcées de hautes performances mécaniques et thermiques avec une bonne aptitude à la mise en forme. Une maîtrise de la faisabilité de la chaîne d’éco-conception, caractérisation et fabrication est nécessaire pour une meilleure optimisation des ressources. À l’échelle mésoscopique les propriétés des tissus de fibres de chanvre secs (tissage simple et tissage en sergé) sont étudiées. Des stratifiés agro-composites fibres de chanvre/matrice polypropylène sont élaborés par thermocompression. Les propriétés mécaniques des stratifiés à différentes températures en traction uni-axiale, cisaillement et traction bi-axiale ont été analysées. Enfin des mises en œuvre de pièces automobiles sont proposées par rétro-conception basée sur la numérisation 3D de la coque du rétroviseur de voiture, la reconstruction de la géométrie; la conception des moules, la mise en forme de la pièce par thermocompression et l’analyse des propriétés mécaniques et de la faisabilité du process. Le comportement des pièces de structure sandwich nids d'abeilles en fibres de chanvre élaborées par thermocompression et par impression 3D est étudié en compression et flexion quatre pointsIn recent years, natural hemp fibres have great potential application in the aerospace and automotive due to their recyclability, renewability and biodegradability. Associated with a polymer matrix, hemp woven fabrics allow the eco-friendly manufacturing of bio-sourced composite parts with high mechanical and thermal properties. A multiscale analysis is essential for the better understanding of the mechanical and thermoforming behaviour of hemp fabrics based composite. In this study, the tensile behaviour of hemp fibre yarns were studied (microscopic scale) and the tensile, shear and biaxial tests were performed to characterize the behaviour of plain and twill dry hemp fibre woven fabrics (mesoscopic scale). Hemp fibre woven fabrics/polypropylene composite laminates were manufactured by thermo-compression process and the mechanical properties of the laminates specimens were analysed at different temperature and for different fibre volume fraction by uniaxial tensile, shear and biaxial test (macroscopic scale). Complex hemp woven fabric composite structures (truncated cone and automotive rear side mirror) were also thermoformed in order to analyse the feasibility of the process. Hemp fibre based honeycomb sandwich structures were manufactured by thermo-compression and 3D printing process. The mechanical behaviour of specimens in compression and four-point bending were analysed experimentally and numerically using Finite Element software
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Patrick, Andrew P. "BLUEGRASS CAPITAL: AN ENVIRONMENTAL HISTORY OF CENTRAL KENTUCKY TO 1860." UKnowledge, 2017. http://uknowledge.uky.edu/history_etds/51.
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This dissertation traces the long-term evolution of the Inner Bluegrass region of central Kentucky with a focus on the period between the first Euro-American incursions into the area and the Civil War era. Utilizing an agroecological perspective that analyzes cultivated landscapes for their ecological features, it explores the ever-shifting mix of cultural and natural influences that shaped the local environment. Most prominently, it reveals the extent to which intertwined strands of capitalism and slavery mingled with biology to produce the celebrated Bluegrass agricultural system.
It begins with an appraisal of the landscape before white men like Daniel Boone arrived, emphasizing the roles native cultures played in shaping regional ecology and arguing for a more complex periodization of eighteenth century Kentucky. The frontier period from the 1770s through the 1790s witnessed a struggle for control over the region linked to competing ideas about how the local landscape might best be used by humans. That Euro-Americans ultimately emerged victorious in this contest held tremendous ecological consequences as domesticated species, organized according to Euro-American agricultural principles, spread across the region. Introduced plants, such as corn, hemp, and bluegrass, and livestock, including hogs, cattle, sheep and horses, increasingly filled ecological niches previously held by native flora and fauna like cane, elk, and buffalo.
As Kentuckians set about refining their influence over the surrounding natural world during the final decades of the eighteenth century and into the nineteenth, their actions demonstrated the varied ecological, economic, and cultural connections and incentives engendered by their slave-reliant, market-oriented agricultural system. These connections exposed the Bluegrass landscape to national and international currents that enriched some Kentuckians, encouraged the exploitation of others, and facilitated a dramatic simplification of the regional ecology in pursuit of economic gain. Yet, the transformations of the local ecology and the demands of those cultivating it also affected national and international events such as the American Revolution, Louisiana Purchase, and the Civil War. The environmental history of the Bluegrass agricultural landscape demonstrates the complexity of influences on the antebellum world and suggests that complexity continues to affect the regional ecology and culture well into the twenty-first century.
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Girgih, Abraham T. "Structural and functional characterization of hemp seed (Cannabis sativa L.) protein-derived antioxidant and antihypertensive peptides." American Oil Chemists' Society, 2011. http://hdl.handle.net/1993/22085.
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ABSTRACT
The aim of this work was to produce enzymatic hemp seed protein hydrolysates (HPH) followed by bioassay guided fractionation to identify antioxidant and antihypertensive peptides. Therefore, simulated gastrointestinal digestion of isolated hemp seed proteins was conducted using consecutive actions of pepsin and pancreatin to produce HPH, which was then separated by membrane ultrafiltration to obtain peptide sizes of <1, 1-3, 3-5, and 5-10 kDa. Evaluation of HPH and its membrane fractions for antioxidant and antihypertensive properties showed that they significantly (P<0.05) scavenged radicals, reduced and strongly chelated metal ions as well as inhibited lipid oxidation. During a 24-hr test, the HPH reduced systolic blood pressure (SBP) of spontaneously hypertensive rats (SHR) after oral administration by a maximum of -30 mmHg when compared to -15 mmHg for the membrane fractions.
To reduce production cost, hemp seed protein meal (HPM) was directly hydrolyzed to a protein hydrolysate (HMH) and was shown to also reduce SBP during 4-8 weeks of dietary feeding. The attenuation of SBP correlated to suppressed plasma levels (0.047-0.059 U/mL and 0.040-0.054 µg/mL) of angiotensin converting enzyme (ACE) and renin, respectively, when compared to the control rats (0.123 U/mL and 0.151 µg/mL). A total of 23 peptides were identified to be present in the HPH. WVYY and PSLPA showed superior in vitro antioxidant properties, while ACE activity was inhibited by WYT (89%), WVYY (91%) and PSLPA (90%). Renin activity was inhibited by WYT (77%), SVYT (87%) and IPAGV (75%). However, oral administration to SHR showed that the pentapeptides (PSLPA and IPAGV) were more effective SBP-reducing agents (-40 mm Hg) when compared to the tri- (-13 mmHg) and tetrapeptides (-36 mmHg). These results show for the first time in literature, the bioactive properties of hemp seed peptides and indicate their potential use as ingredients to formulate antioxidant and antihypertensive functional foods and nutraceuticals.
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Réquilé, Samuel. "De la plante aux biocomposites : caractérisation des interfaces multiples et étude des paramètres pertinents Exploring the link between flexural behaviour of hemp and flax stems and fiber stiffness Peeling experiments for hemp retting characterization targeting biocomposites Deeper insight into the moisture-induced hygroscopic and mechanical properties of hemp-reinforced biocomposites. Interfacial properties of hemp fiber/epoxy: effect of moisture sorption and induced hygroscopic stresses Propriétés hygroscopiques et mécaniques d'un biocomposite renforcé par des fibres de chanvre." Thesis, Lorient, 2019. http://www.theses.fr/2019LORIS529.
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Les préoccupations environnementales de l'industrie et les stratégies visant à développer un système économique plus durable suscitent un intérêt croissant pour la recherche dans le domaine des biocomposites. Le fort caractère polaire et hydrophile des fibres végétales entraîne, lors de leur utilisation comme renfort, une complexité de mise en œuvre et des limites en termes de transfert de charge à l’interface fibre/matrice. Ces verrous pour le développement des biocomposites sont les lignes directrices de ce travail de thèse s'inspirant de la présence des interfaces au sein des tiges de chanvre. L’évolution progressive de la microstructure et des propriétés mécaniques est cruciale pour l'intégrité et le fonctionnement de la tige à travers des régions de transition. Ces interfaces, potentiels maillons faibles de la structure, sont étudiées en appliquant un processus de rouissage impactant la microstructure interne et la cohésion tissulaire. Des tiges aux fibres élémentaires, l'étude du comportement mécanique des systèmes naturels est une source d’inspiration pour un transfert des principes fondamentaux des biocomposites. Visant à accroître la compréhension de l'effet de l'humidité présente dans l’environnement lors des utilisations composites, l’analyse des propriétés hygro-mécanique permet de mettre en évidence des performances optimales de composites unidirectionnels de part un effet bénéfique de la sorption d’eau. Des études à l'échelle microscopique ont permis d’attribuer une contribution importante du comportement hygroscopique aux performances de l'interface fibre/matrice par la création de contraintes résiduelles et de mécanismes d'adhésion capillaire. Généralement décrite comme un inconvénient, ce travail de recherche montre que la sensibilité à l'eau des fibres végétales ainsi que la sorption de vapeur d’eau dans un biocomposite pourraient favoriser le transfert de charge et être bénéfiques pour leurs performances mécaniquesIndustry environmental concerns and strategies to become part of a more sustainable economic system, leads to a growing interest in research on biocomposite. The strong polar and hydrophilic nature of plant fibers leads, when used as a reinforcement, to a complexity of biocomposite manufacturing and limits in terms of load transfer at the fiber/matrix interface. These major locks (fiber polarity and moisture sensitivity) for biocomposites development are the guidelines of this thesis work taking its inspiration in the design of hemp stem tissue interfaces. The multi-scale evolution of gradient microstructure and internal mechanics is crucial for the integrity and functioning of the stem through smooth transitions regions. These potential weak interfaces are investigated by applying a retting process that affect the stem internal microstructure and tissue cohesion. From the stems of agricultural crops to the hierarchical elementary fibers, studying the mechanical behavior of natural systems may serve as inspiration for a biomimetic transfer of the fundamental principles to fiber-reinforced composites. Aimed at increasing the understanding of the effect of moisture present during composite use, hygro-mechanical coupling highlights an optimum in hemp fibre-based unidirectional composites performances from a beneficial effect of moisture sorption. Deeper analysis at the micro-scale attributed a significant contribution of this hygroscopic behavior to fiber/matrix interface performances through the creation of residual stresses and capillary adhesion mechanisms. Generally described in the literature as a drawback, this research demonstrates that water sensitivity of plant fibers and moisture sorption in biocomposite could promote load transfer and be beneficial for their performance
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Kamat, Jaymini. "Effect of harvesting time on the physical, chemical and pulping properties of hemp, Cannabis sativa L." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0015/MQ53453.pdf.
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Mayembo, Evrard. "The influence of different chemical treatments on the mechanical properties of hemp fibre-filled polymer composites." Master's thesis, Faculty of Engineering and the Built Environment, 2021. http://hdl.handle.net/11427/33797.
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The fluctuation of engineering and general-purpose polymer prices, rapid exhaustion of fossil fuel world-wide reserves and heightened awareness about environment have led the research community to explore the use of natural biodegradable raw materials as substitutes for manmade resources. Natural fibres are considered as substitutes for synthetic fibres in reinforced polymer matrix composites. Increased interest has been shown in natural fibres from plants such as cotton, jute, hemp as replacements for aramid, glass, and carbon fibres. This is due to their biodegradability, low cost, low density, and satisfactory strength to weight ratio. However, they present certain disadvantages compared to synthetic fibres which include high moisture sorption rates, low durability, and weak fibre/matrix bonding strength. The poor adhesion between natural fibres and polymer matrices leads to poor mechanical properties for natural fibre reinforced composites. Improvement of the fibre/matrix interface is required to increase the mechanical properties of the natural fibre filled polymer composite In this study, the influence of selected chemical treatments on the mechanical properties of hemp-filled epoxy composites was investigated. The aim of this study was to enhance fibre/matrix interface and hence the mechanical properties of hemp yarn-reinforced epoxy composites by modifying the chemical nature of a high crystallinity hemp yarn through chemical treatments such as alkalization, silanization (3-aminopropyltriethoxysilane) and a maleic anhydride treatment. The effectiveness of the chemical treatments was assessed by means of XRD, FTIR and TGA. Density measurements of as-received yarns (1.42-1.45 g cm-3 ) were within the range reported in the literature. Crystallinity measurements revealed the astreated yarns as having high crystallinity indices (87% weft and 84.7 warp yarns). The surface treatments used increased the crystallinity index only slightly. A decision was taken to use warp yarns (UTS = 799 MPa) rather than warp yarns (UTS = 503 MPa). Silane treatment reduced the tensile strength of yarns slightly (753 MPa) while the treatment of the fibres with maleic anhydride (562 MPa) and alkali treatment (518 MPa) had a much more significant effect on ultimate tensile strength. By contrast the modulus of the treated yarns all increased compared to the as-received yarns. Silanization was confirmed by energy dispersive X-ray spectroscopy while maleation was confirmed by the presence of characteristic absorbances in FTIR spectra. TGA revealed that silanization improved fibre thermal stability while maleic anhydride treatment did the opposite, possibly due to decarboxylation reactions. Four type of fibre/matrix interfaces, based on the treated and non-treated fibres, were generated through the production of the hemp reinforced epoxy composite plates. The results showed insignificant variations in the mechanical and thermal properties compare with the as-received hemp-filled epoxy composites which showed the high mechanical properties and thermal stability. The silanization and alkalization slightly decreased the properties of their respective properties although this was deemed statistically insignificant. The maleic anhydride treatment worsened the mechanical properties significantly. Scanning electron microscopy revealed appreciable fibre-matrix debonding which is indicative of a weak fibre/matrix interface. This was postulated as a reason for the lack of any significant reinforcement of the epoxy composites by maleic anhydride treated fibres. The tensile properties were also predicted and no statistically significant differences were observed although the experimental strengths values appeared to be lower than the predicted strengths. In general, the lack of appreciable improvement in mechanical properties of as-received fibres was concluded to be due to the initially high crystallinity of the as-received fibres. This provided little scope for further alkalization to change the surface significantly as little further removal of hemicellulose and lignin could occur.
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RIBEIRO, Ana Maria Motta. "O p?lo sindical do subm?dio S?o Francisco: das lutas por reassentamento ? incorpora??o do cultivo de maconha na agenda." Universidade Federal Rural do Rio de Janeiro, 2008. https://tede.ufrrj.br/jspui/handle/tede/1040.
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Previous issue date: 2008-02-29This paper tries to analyze, in a critical way, the syndicalism in the Polo Sindical do Subm?dio S?o Francisco, inserted in a region identified by the Press as the Hemp Polygon. It intends to understand, from the field work, the insertion of the subject of the hemp plantation (criminalized) in the agenda of the Polo Sindical do Subm?dio S?o Francisco. The study intends to understand this phenomenon through a historical retrospection and an analysis about the region understood as a social-political production of territorialities. Also, it develops an attempt of explanation of the crossing between illegal agriculture and the dynamic of syndical struggle for the recovery of the version which the entity produces and legitimates as its biography in order to understand how and by whom the justification of that crossing is built. In this process of sociological undoing of the Hemp Polygon, it is shown how, when and through which means the subject of the illegal cultivation enters the agenda of the entity.
Esta TESE tenta analisar de modo cr?tico o sindicalismo do P?lo Sindical do Subm?dio S?o Francisco inserido numa regi?o identificada pela M?dia como o Pol?gono da Maconha . Pretende compreender, a partir de pesquisa de campo, a entrada do tema do plantio de maconha (criminalizado) na agenda do P?lo Sindical do Subm?dio S?o Francisco. O estudo pretende entender esse fen?meno atrav?s de uma retrospectiva hist?rica e de uma an?lise sobre a regi?o entendida como uma produ??o s?cio pol?tica de territorialidades. Tamb?m desenvolve uma tentativa de explica??o do cruzamento entre agricultura il?cita e a din?mica da luta sindical, pela recupera??o da vers?o que a entidade produz e legitima como sua biografia para entender como ? elaborada e por quem, a justificativa desse cruzamento. Neste processo de desconstru??o sociol?gica do Pol?gono da Maconha, se destaca como, quando e atrav?s de que media??es o tema do cultivo il?cito entra na agenda da entidade.
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Johnson, Jeffrey Brian. "Effect of flax and hemp seed oils on erythrocyte concentrations of eicosapentaenoic and docosahexaenoic acids in vegetarians." Thesis, University of Hawaii at Manoa, 2003. http://hdl.handle.net/10125/7037.
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Flax and hemp seed oils are rich sources of alpha-linolenic acid (ALA; 18:3n-3), which can be converted to eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) in humans. We investigated the effects of these oils on erythrocyte concentrations of EPA, DHA, other fatty acids, and plasma lipids in healthy vegetarians. Twenty-two subjects consumed either one tablespoon of flax (7.1 g ALA) or hemp seed oil (2.2 g ALA) daily for twenty-eight days. Diet records were collected at baseline and during supplementation. Blood samples were collected at baseline and post-supplementation. No significant increases in plasma EPA, DHA or dihomo-gamma-linolenic acid (DGLA; 18:3n-6) were observed in either group. Significant increases in plasma high-density lipoprotein cholesterol (HDL) concentrations were observed in both groups. Flax and hemp seed oils were not effective at increasing erythrocyte EPA, DHA or DGLA concentrations but were effective at increasing HDL concentrations.xv, 114 leaves
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Hultkrantz, Martina. "An overview on the environmental impacts of synthetic leather made of hemp fiber with preliminary lifecycle assessment." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233980.
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This report covers a preliminary life cycle assessment (LCA) on imitation leather made from hemp fiber (hemp leather) and a comparison to bovine leather, to examine whether hemp leather is an environmentally sustainable alternative. The bovine leather industry is responsible for heavy chemical use and emissions, detrimental effects to the environment as well as to human health. The United Nations (UN) and other organizations call for immediate action against the animal product industry sector to greatly reduce emissions and protect the environment. Hemp is a versatile plant that can be used for many things, including paper, composites, textiles, food and medicine, and is probably a suitable material for imitation leather. The hemp plant requires little inputs, grows fast and without pesticides, has positive effects on the environment and can be cultivated on every inhabited continent. The preliminary LCA was based on a patent describing the manufacturing process of hemp leather completed with data from literature and a few assumptions made. LCA-results for bovine leather were collected from literature and the two leather fabrics were then compared. The comparison showed that hemp leather is superior to bovine leather in all compared categories except for water consumption and hazardous waste. Bovine leather had 99% more energy use, 78% higher acidification potential (AP), 99,9% higher eutrophication potential (EP) and 83% higher global warming potential (GWP) than hemp leather. The large water consumption in the manufacturing phase of hemp leather is possible to be explained by over dimensioning of inputs. The report concludes that hemp leather would be the environmentally and ethically admirable choice between the two leathers and that more research on more modern methods of manufacturing it should be performed.Denna rapport omfattar en preliminär livscykelanalys (LCA) på syntetiskt läder gjort av hampfiber (hampläder) och en jämförelse med nötskinn, för att undersöka om hampläder är ett miljövänligt alternativ. Nötskinnsindustrin är ansvarig för stor kemikalieanvändning och tunga utsläpp, skadlig inverkan på miljö samt människors hälsa. Förenta nationerna och andra organisationer fordrar till omedelbar handling mot djurindustrisektorn för att drastiskt minska utsläpp och skydda miljön. Hampa är en mångsidig växt som kan användas inom många olika applikationer, såsom till papper, kompositer, textiler, mat och medicin, och är förmodligen ett passande material till imitationsläder. Hampan behöver liten mängd tillförd energi, växer fort och utan bekämpningsmedel, har positiva effekter på miljön och kan odlas på alla bebodda kontinenter. Den preliminära LCA:n är baserad på ett patent beskrivande hampläders produktionsprocess, kompletterat med data från litteratur samt några antaganden. LCA-resultat från nötskinnsproduktion samlades från litteratur och resultaten från de två lädertyperna jämfördes sedan. Jämförelsen visade att hampläder är överlägset nötskinn i alla jämförda kategorier utom vattenkonsumtion och farligt avfall. Nötskinn har 99% högre energianvändning, 78% högre försurningspotential (AP), 99,9% högre övergödningspotential (EP) och 83% högre potential till global uppvärmning (GWP) än hampläder, enligt resultaten. Hampläders produktionsprocess stora vattenkonsumtion kan troligtvis förklaras av en överdimensionering av indata. Denna rapport drar slutsatsen att hampläder skulle vara det mest miljövänliga och etiskt försvarbara valet mellan de två lädertyperna och att modernare produktionsmetoder för hampläder bör studeras.
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Stringer, Carol Elizabeth. "EVALUATING HEMP (CANNABIS SATIVA) AS A FORAGE BASED ON YIELD, NUTRITIVE ANALYSIS, AND MORPHOLOGICAL COMPOSITION." UKnowledge, 2018. https://uknowledge.uky.edu/pss_etds/104.
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This experiment examined the forage potential of hemp (Cannabis sativa) and kenaf (Hibiscus cannabinus). The objectives were to evaluate yield and forage nutritive value (i.e. NDF, ADF, ADL, IVTD, and CP) fluctuations over the course of a growing season based on planting date, morphological composition, and management. Three types of hemp (grain, fiber, and a dual- purpose type) and kenaf were planted on two dates and were sampled approximately every two weeks throughout the growing season at the University of Kentucky (UK) Research Farm in Lexington, KY. Subsamples were separated into morphological components (i.e. leaf, flowers, stem, core fiber, and bast fiber) while the remainder of the sample was ground for laboratory analysis. All samples were scanned in Foss 6500 NIRS and wet chemistry analytical methods were utilized on a subset of samples to develop equations to predict the nutritive value of the remaining samples. Significant interactions for forage type, planting date, and harvest time were observed for yield, % floral components, % bast, and ADL. Significant interactions occurred between planting date and harvest date as well as type and harvest date for NDF, ADF, digestibility, crude protein, % leaf, % core, and % stem. Overall, forage nutritive value declined with increased plant maturity. The later planting date reduced the vegetative growth period, resulting in reduced leaf content, yield, and forage nutritive value. The performance of kenaf in this study indicates that it may be a better alternative forage than hemp due to remaining vegetative longer and having superior nutritive value. Better selection and the development of new hemp varieties with different photoperiod requirements could lengthen the vegetative state and may result in yields and nutritive values that are more competitive with kenaf and other typical forages.
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CALZOLARI, DAVIDE. "OPTIMIZING CANNABIS SATIVA CULTIVATION TO INCREASE HIGH ADDED-VALUE COMPOUNDS IN SEED AND THRESHING RESIDUE." Doctoral thesis, Università Cattolica del Sacro Cuore, 2018. http://hdl.handle.net/10280/39868.
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Il rinnovato interesse nella coltivazione della canapa industriale non è stato supportato da studi approfonditi e generalmente si basa su esperienze dirette di coltivazione. Questo studio si prefigge come obbiettivo quello di sfruttare tutte la parti della pianta di canapa per migliorare l’economicità complessiva della sua coltivazione tramite l’uso di tecniche agronomiche e di pratiche post-raccolta. La Cannabis sativa ha un vasto campo di applicazioni, tra cui le più promettenti in termini di ritorno economico sono il cosmetico e il farmaceutico. I composti naturali più interessanti della Cannabis sono i cannabinoidi non-psicoattivi cannabidiolo (CBD) e cannabigerolo (CBG) presenti in elevate concentrazioni nelle foglie e nelle brattee di Cannabis. Altri metaboliti secondari prodotti dalla canapa e di grande interesse sono le cannflavine, una classe di prenil-flavonoidi caratteristico di questa specie. Nel primo e nel secondo capitolo la dinamica temporale di accumulo dei metaboliti secondari ad elevato valore aggiunto è stata monitorata per alcune delle varietà più comuni di canapa industriale ed è stata determinata la produzione potenziale di questi composti. Nel terzo capitolo una collezione di semi di canapa è stata valutata per le caratteristiche morfologiche e per il contenuto e la qualità dell’olio. Concludendo questo studio contribuisce allo sviluppo di una coltivazione della canapa per le molteplici destinazioni d’uso dei semi e del fitocomplesso.Rapidly growing interest into industrial hemp cultivation is not supported by strong data and generally is referred to a limited experience on field cultivation. This study aims to exploit all the parts of hemp plant, in order to ameliorate the overall economy of its cultivation and by providing information on agronomic management and post-harvest operations. Cannabis sativa has a wide range of industrial applications and the most promising, in terms of economic revenues, are the cosmetic and pharmaceutics. The most interesting phytochemicals in Cannabis are the cannabinoids, in particular the non-intoxicating compounds cannabidiol (CBD) and cannabigerol (CBG), present at high concentration in the leaves and bracts of Cannabis. Some other promising secondary metabolites of hemp are cannflavins, a class of prenyl-flavonoids characteristic of this species. In the first and second chapter the time course accumulation of high added-value compounds was monitored for some of the most common industrial hemp cultivars, and the potential production was assessed. In the third chapter a collection of hemp seeds was evaluated for its morphological characteristics and for its oil content and quality. In conclusion this thesis contributes to a further development of multipurpose hemp cultivation for seed and phytocomplex production.