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Статті в журналах з теми "Plant fibers Testing"
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Hamad, Sameer F., Nicola Stehling, Simon A. Hayes, Joel P. Foreman, and C. Rodenburg. "Exploiting Plasma Exposed, Natural Surface Nanostructures in Ramie Fibers for Polymer Composite Applications." Materials 12, no. 10 (May 18, 2019): 1631. http://dx.doi.org/10.3390/ma12101631.
Повний текст джерелаАнотація:
Nanoscale surface morphology of plant fibers has important implications for the interfacial bonding in fiber-polymer composites. In this study, we investigated and quantified the effect of plasma-surface modification on ramie plant fibers as a potential tool for simple and efficient surface modification. The extensive investigation of the effects of plasma treatment of the fiber surface nano-morphology and its effect on the fiber-polymer interface was performed by Low-Voltages Scanning Electron Microscopy (LV-SEM), infrared spectroscopy (FT-IR) analysis, fiber-resin angle measurements and mechanical (tensile) testing. The LV-SEM imaging of uncoated plasma treated fibers reveals nanostructures such as microfibrils and elementary fibrils and their importance for fiber mechanical properties, fiber wettability, and fiber-polymer matrix interlocking which all peak at short plasma treatment times. Thus, such treatment can be an effective in modifying the fiber surface characteristics and fiber-polymer matrix interlocking favorably for composite applications.
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Anil Kumar, V., T. Sai Neeraj, and Y. Meghana. "Mechanical Characterization and Fabrication of Banana and Pineapple Fibers." IOP Conference Series: Materials Science and Engineering 1248, no. 1 (July 1, 2022): 012061. http://dx.doi.org/10.1088/1757-899x/1248/1/012061.
Повний текст джерелаАнотація:
Abstract A composite material is made up of two or more materials with differing properties that are combined to enhance material properties. Various natural fibers are abundant in India such as seed hairs like cotton, flax, hemp leaf fibers, sisal, coconut, jute, pineapple, luffa, etc. Since natural fibers stand-alone don't have distinct mechanical properties. To attain good mechanical properties and to explore worth-added applications. The evolvement of natural fiber composites in India is to avoid the depletion of resources. The reason for the desirability of this field over the traditionally used synthetic fiber is that natural fibers have low density, high toughness, are environment friendly, fully biodegradable, renewable, and low cost. The biodegradability of plant fibers can impart a healthy ecosystem while their low cost & high performance fulfill the economic interest of industries. The purpose of this paper is to develop a new natural fiber composite with banana stem fibers and pineapple fibers. Resins and hardeners are chosen depending on the mechanical properties of the fibers, and fabrication was done accordingly. Finally, conclusions are drawn after Mechanical Testing of the composites. The properties of the composites are discussed.
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Arivendan, Ajithram, Winowlin Jappes J T, Siva Irulappasamy, and Brintha N Chris. "Water hyacinth (EichhorniaCrassipes) polymer composites properties - aquatic waste into successful commercial product." Metallurgical and Materials Engineering 28, no. 1 (March 25, 2022): 157–69. http://dx.doi.org/10.30544/752.
Повний текст джерелаАнотація:
In modern times, the demand for natural fibers is increased due to low density, low cost, recyclability, and biodegradable properties. Following work deals with the aquatic waste of water hyacinth plant fiber. The main intent of this work is to utilize the hyacinth plant into a successive manner and convert this plant into some commercial products. It is used as reinforcement material and epoxy polymer resin in matrix material with a suitable percentage of hardener (10:1). A new method such as a mechanical way of extraction process is introduced in this work. The different weight percentage of the hyacinth fiber is reinforced with matrix material like 15, 20, 25, 30, and 35%. With the help of a compression molding, machine water hyacinth reinforced fiber composite is produced by using 1500 PSI pressure and 110 °C, 100 °C of upper and lower plate temperature. A composite sample is cut into as per ASTM standards and the mechanical tests like tensile, flexural, impact test is conducted by using universal testing machine (UTM), and Charpy impact test machine. Based on the final mechanical test results, the 30% of hyacinth composite sample tensile 36.48 MPa, flexural 48.62 MPa, impact 0.5 J, and hardness 98 attained then, the hyacinth composite samples are adopted into water and chemical absorption test with 10 hours, 1week, 1month of continuous monitoring. Based on the final results, hyacinth fiber is strongly recommended to use an alternative of synthetic fibers and conventional natural fibers. The hyacinth composite is strongly recommended for the usage of commercial and household applications.
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Kumar, R., R. Jyothilakshmi, and H. L. Nandeesha. "Synthesis and testing for mechanical integrity of nano cellulose composites." Journal of Mines, Metals and Fuels 69, no. 12A (April 28, 2022): 37. http://dx.doi.org/10.18311/jmmf/2021/30092.
Повний текст джерелаАнотація:
This scientific research focused on extraction of the polymer from an appropriate source and preparation of films with mechanical integrity and desirable chemical properties. Reinforcement of said films with nano-fillers like Nano silica and clay were administered to reinforce their mechanical properties. Further development on these films would contribute to eliminating plastics and replacing them with better and sustainable materials. Cellulose may be a biopolymer found in plant cell walls which will be derived from biomass sources like sugarcane. It is one among the main constituents of plant cell walls alongside hemicellulose and lignin. “Cellulose consists of long unbranched fibers of glucose held together by hydrogen bonds”. It is widely utilized in paper, plastics, coatings and casings.
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Rusmini, Dwinita Aquastini, Riama Rita Manullang, Daryono Daryono, Ali Sadikin, and Hadi Kuncoro. "PHYTOCHEMICAL ASSAY AND ANTIOXIDANT ACTIVITY AGAINST DPPH OF ETHANOL EXTRACT FROM KENAF LEAF (Hibiscus cannabinus L.)." Journal of Tropical Pharmacy and Chemistry 4, no. 5 (June 30, 2019): 203–8. http://dx.doi.org/10.25026/jtpc.v4i5.202.
Повний текст джерелаАнотація:
Kenaf (Hibiscus cannabinus L.) is an environmentally friendly natural fiber-producing plant that can produce diversified products, such as paper, wallcover, car interior, geotextile, soil safer, fiber drain, particle board, and plastic reinforcement as well as biofuel industry raw materials. Kenaf plant is a plant that has been only part of the fibers of the stem alone so that many unprofitable side products such as kenaf leaves after harvesting only as a waste. In Africa the leaves of kenaf are widely used as medicine This study aims to analyze phytochemical compounds and study the antioxidant activity of the kenaf leaf. The study started by doing phytochemical test and analyzing antioxidant in kenaf leaf and then testing its antioxidant activity with DPPH method. The results showed that the leaves of kenaf contain secondary metabolites of phytochemical compounds such as flavonoids, alkaloids, steroids, saponins, carbohydrates and tannins and have antioxidant activity that is quite good that is 44.4813 ppm.
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Koronis, Georgios, Arlindo Silva, and Michael Ong. "Comparison of Structural Performance and Environmental Impact of Epoxy Composites Modified by Glass and Flax Fabrics." Journal of Composites Science 6, no. 10 (September 27, 2022): 284. http://dx.doi.org/10.3390/jcs6100284.
Повний текст джерелаАнотація:
Comparing the structural performance and environmental impact of parts made of natural and synthetic fibers has become increasingly important for industry and education, as the benefits of one type of fiber over another are not always clear. The current work discusses the advantages and disadvantages of using natural and synthetic fibers and compares the flexural performance of parts made of each of these fibers and their environmental impact. This paper investigates the flexural behavior of epoxy composites modified by glass and flax fabrics through experimental, numerical, and analytical studies. Specimens with various fabrics (dried and non-dried) were fabricated to test their performance. The failure of unidirectional glass and flax fiber reinforced polymer composite laminate was examined by destructive testing. A finite-element model was developed, and the mechanical behaviors of fiber-reinforced composites were predicted in a three-point bending test. Experimental results were compared to numerical analysis to validate the model’s accuracy. A life cycle assessment (LCA) was employed to determine the climate impact of composite production. The analysis revealed a decreased environmental effect of plant-based panels suggesting that they are less energy and CO2 intensive than synthetic solutions. The LCA model can be applied in further studies of products that consist of or use flax-based composites.
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Machaka, Meheddene, Jamal Khatib, Safaa Baydoun, Adel Elkordi, and Joseph J. Assaad. "The Effect of Adding Phragmites australis Fibers on the Properties of Concrete." Buildings 12, no. 3 (March 1, 2022): 278. http://dx.doi.org/10.3390/buildings12030278.
Повний текст джерелаАнотація:
Nowadays, the increasing demand for concrete is causing serious environmental impact including pollution and waste generation, rapid depletion of natural resources, and increased CO2 emission. Incorporating natural fibers in concrete can contribute toward environmental sustainability. This paper is concerned with the use of natural fibers obtained from the plant species Phragmites australis (PA). The plant is invasive, and rapidly grows abundantly along rivers and waterways, causing major ecological problems. This research is part of a wide range investigation on the use of natural fibers produced from the stem of PA plants in concrete. Using a machine, plant stems were crushed into fibers measuring 40 mm in length and 2 mm in width, and treated with 4% NaOH solution for 24 h. A total of four concrete mixes were prepared with varying additions of treated fibers, ranging from 0% to 1.5% (by volume) with water to cement ratio of 0.5% (by volume). Concrete specimens were tested at 3, 7, and 28 days. Testing included compressive strength, density, total water absorption, and capillary water absorption. The results show that incorporating PA natural fibers reduces the water absorption by total immersion and capillary action by up to 45%. Moreover, there is a negligible decrease in concrete density and strength when fibers were added. It is concluded that adding up to 1.5% natural PA fibers to concrete is a feasible strategy to produce an eco-friendly material which can be used in the production of sustainable building material with adequate mechanical and durability performance.
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FERRAZ, RENER LUCIANO DE SOUZA, PATRÍCIA DA SILVA COSTA, IVOMBERG DOURADO MAGALHÃES, PEDRO ROBERTO ALMEIDA VIÉGAS, JOSÉ DANTAS NETO, and ALBERTO SOARES DE MELO. "PHYSIOLOGICAL ADJUSTMENTS, YIELD INCREASE AND FIBER QUALITY OF 'BRS RUBI' NATURALLY COLORED COTTON UNDER SILICON DOSES." Revista Caatinga 35, no. 2 (June 2022): 371–81. http://dx.doi.org/10.1590/1983-21252022v35n213rc.
Повний текст джерелаАнотація:
ABSTRACT Globally, the demand for food and consumer products has accompanied population growth, forcing the agriculture and livestock sector to optimize the production systems. In the specific case of agriculture, using improved edible and energetic plant cultivars associated with abiotic stress-reducing substances is a strategy adopted to solve this problem. This investigation aimed to evaluate whether silicon (Si) promotes physiological adjustments, an increase in production, higher yield, and improved quality of naturally colored cotton fibers. Five doses of silicon (0 (control), 5, 10, 15, and 20 kg ha−1) were tested in a completely randomized design. The variables assessed were physiological adjustments, production, yield and quality of fibers produced by BRS Rubi cultivar. Data were submitted to principal component analysis, multivariate and univariate analyses of variance, and multiple linear regression analysis. Silicon promotes physiological adjustments, enhanced production, yield, and quality of naturally colored cotton fibers of BRS Rubi cultivar grown in the Brazilian semiarid region. Fiber quality in plants that have been treated with Si is within the expected values for this cultivar and by the international standard D-4605 of the American Society for Testing and Materials. 10 kg ha−1 of Si is recommended to increase fiber quality of naturally colored cotton cv. BRS Rubi.
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Ramu, S., and N. Senthilkumar. "Approaches of material selection, alignment and methods of fabrication for natural fiber polymer composites: A review." Journal of Applied and Natural Science 14, no. 2 (June 18, 2022): 490–99. http://dx.doi.org/10.31018/jans.v14i2.3351.
Повний текст джерелаАнотація:
The recent superiority of the composite materials is cautiously focusing on environmental adoption of natural fiber composites. The major source of the natural fiber materials covered in the globe, especially natural fibers, is plant-based, animal-based and mineral-based. Eco friendly based material can save the environment and recycling of the material is possible, as well as important criteria. Hence engineers ultimately focused on natural fiber polymer matrix materials to save the environment, pollution control, plastic manipulation, etc. The literature work was studied to identify natural fiber material possession. The major goal of the present review was to identify material characterization and appropriate application, mainly offering to enhance mechanical properties, flexural strength, electrical properties, thermal properties etc. The major consequence of the natural fiber is hydrophilic treatment. There is poor interfacial adhesion between the addition/filling substances and poor mechanical characteristics. All of these shortcomings constitute a critical issue. This review presents numerous sorts of natural and synthetic polymers, natural fibres such as jute, ramie, banana, pineapple leaf fibre, and kenaf, etc.; short and long fibre loading methods, fibre fillers in micro and nanoparticle, American society of testing and materials (ASTM) standard plate dimensions, fabrication methods such as hand lay-up process, spray lay-up process, vacuumed-bag, continuous pultrusion, and pulforming process, etc.; industries and home appliances such as automotive parts, building construction, sports kits, domestic goods, and electronic devices. The review lists various material combinations, fibre loading, fillers, and matrix that can aid in the improvement of material properties and the reduction of failures during mechanical testing of composites.
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Obi LE, Uwanugo RG, and Uchejiora M. "Investigation of water and heat response to the compression property of raffia, bamboo and coconut fiber-reinforced-polyester composites." International Journal of Frontiers in Engineering and Technology Research 1, no. 1 (November 30, 2021): 045–60. http://dx.doi.org/10.53294/ijfetr.2021.1.1.0045.
Повний текст джерелаАнотація:
The dearth of construction materials has been the bane of the global construction industry. In a bid to curb this menace, it becomes very imperative to source for construction materials from discarded and least costly materials from raffia, bamboo and coconut fibers. This research investigates the hydrothermal response of plant fiber-reinforced-polyester composites (PFRC). Imperical methods were used to determine the mechanical properties of PFRC (bamboo, raffia and coconut fiber composites), with the usage of Monasanto Tensometer testing machine. All the samples were chemically modified with 12.5g of sodium hydroxide. Numerical and micro-soft excel graphics were used to model compressive responses of the PFRCs. From the analyses, the compressive strengths of raffia, bamboo and coconut composites are 40, 45 and 38MPa respectively.
Дисертації з теми "Plant fibers Testing"
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Gavérina, Ludovic. "Caractérisation thermique de milieux hétérogènes par excitation laser mobile et thermographie infrarouge." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0012/document.
Повний текст джерелаАнотація:
De nos jours, les matériaux composites sont très largement utilisés dans l’industrie aéronautique et aérospatiale car ils ont de très bonnes tenues mécaniques, mais ces matériaux comportent de fortes hétérogénéités dues aux fibres et aux liants qui les constituent. Ainsi, depuis de nombreuses années, l’équipe TIFC «Thermal Imaging Fields and Characterization » du département TREFLE de l’institut I2M développe des méthodes de mesure des propriétés thermophysiques de matériaux hétérogènes dans le plan ou dans l’épaisseur. Ces méthodes sont très variées du point de vue des méthodes inverses (transformée intégrale, double décomposition en valeurs singulières, …) ou expérimentale (Flash, diode laser, …). Le faible coût des diodes lasers et des systèmes de déplacement de miroirs galvanométriques ont permis de développer un système complet de scanner optique laser, monté sur un banc de mesure. Il permet de revisiter les différents types de sollicitations thermiques et de réaliser une infinité de combinaisons spatiotemporelles d’excitations thermiques par méthode laser. Ceci est une des principales originalités de ce travail. De nouvelles méthodes inverses basées sur la réponse thermique au point source impulsionnel et sur la séparabilité des champs de température ont été proposées. Ces méthodes ont permis d’estimer le tenseur de diffusivité thermique selon les axes principaux d’anisotropie, mais aussi hors des axes du repère de l’image, où il est possible de déterminer l’orientation des axes d’anisotropie, lorsque le transfert de chaleur s’effectue hors des axes du repère de l’image. Ces méthodes ont permis d’obtenir des résultats intéressants comptetenu de leur simplicité. De plus, elles ont permis d’obtenir des cartographies de diffusivités thermiques dans le plan car, comparées aux autres méthodes, elles permettent d’obtenir des estimations du tenseur de diffusivité thermique localement grâce à l’obtention d’une cartographie de flux thermique surfacique via le scanner optique laserNowadays, composite materials are widely used in the aeronautic and aerospace industries because of their high mechanical resistance. However, they have a large heterogeneity due to the fiber and matrix they are made of. In this way, for many years, the TIC team «Thermal Imaging Fields and Characterization » from TREFLE department of I2M laboratory develops methods to measure thermal in-plane properties of heterogeneous materials such as inverses (integral transforms, double singular value decomposition…) or experimental (Flash, laser diode…) methods. The recent progress made in optical control, lasers and infrared (IR) cameras enables the development of a new scanning system (based on galvanometer-mirror) which allows the easy control of a laser hot spot spatial and temporal displacements over a plane surface. The low cost of laser diodes and optical control (galvanometric mirror) systems allows to develop a laser scanning system fixed on a test bench. We can revisit the different types of thermal excitation and realize infinite spatio-temporal combinations of thermal excitations by laser method. This is one of this thesis aims. New inverse methods based on the thermal response to an instantaneous point source heating, and temperature fields separability, have been proposed. These methods allow to estimate the thermal diffusivity tensor along the main axes of anisotropy, but also out of those axes, where it is possible to estimate the anisotropy axes orientation when the heat transfer takes place out of the image axes. These methods have produced interesting results in view of their simplicity. Moreover, they made it possible to obtain in-plane thermal diffusivities maps because, compared to the other methods, they allow to obtain, locally, thermal diffusivity tensor estimations by getting a surface heat flux map using the laser optical scanner
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Yang, Qi. "Out-of-plane strengthening of unreinforced masonry walls using FRP techniques." Thesis, 2007. http://hdl.handle.net/2440/69431.
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Wright, Thomas J. (Thomas John). "Sensitivity of Hashin damage parameters for notched composite panels in tension and out-of-plane bending." Thesis, 2012. http://hdl.handle.net/1957/35802.
Повний текст джерелаАнотація:
When using Finite Element Analysis (FEA) to model notched composite panels, the values of certain material properties can have a great effect on the outcome of the simulation. Progressive damage modeling is used to model how a composite structure will fail, and how that failure will affect the response of the structure. Many different progressive damage models exist, but the formulation known as Hashin damage is used to model failure in tension and out-of-plane bending in this study. This model has ten different material properties that are used to define the damage response of the material. Each of these material properties must be calculated experimentally in a time consuming and expensive process. A method of determining which properties will have the greatest effect on the model, and therefore, which to spend the most money on accurate tests, is a factorial analysis sensitivity study. Studies of this nature have been used in many different situations regarding material properties testing and optimization.
The work presented in this study uses several factorial analysis designs to perform a sensitivity study on the ten Hashin damage parameters in a variety of situations. Five different ply layups are used in modeling specimens that are loaded in tension and out-of-plane bending. The results of this study show that the significant factors depend on the ply layup and loading scenario, but there are generally less than three factors that play a significant role in modeling the failure of the panels. This means that in most cases, rather than spending substantial money on finding ten different material properties, the time and money can be focused on a small subset of the properties, and an accurate model can still be achieved. While the results of the scenarios presented may not apply to all scenarios, the methods presented can be used to perform a similar study in other specific scenarios to find the significant factors for that case.Graduation date: 2013
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Turek, Martin Edward. "In-plane shake-table testing of unreinforced masonry walls strengthened with fibre reinforced-plastics." Thesis, 2002. http://hdl.handle.net/2429/13247.
Повний текст джерелаАнотація:
Unreinforced-masonry structures have typically performed poorly during earthquakes.
Many structures that were built with this material still have a continued economic and
social benefit, even though they may be structurally unfit. For this reason, many seismic
retrofit schemes have been developed, one being the use of composite materials.
Various testing has been performed on these materials, and on some of their structural
applications in seismic retrofits. Limited full-scale shake table testing has been
performed, and a research collaboration between The University of British Columbia and
Public Works and Government Services Canada, Pacific Region was established to
explore this type of testing on the application of these materials.
A series of in-plane shake-table tests were performed on a set of unreinforced and FRP
strip reinforced concrete-masonry walls. The unreinforced walls were used as a
benchmark for the study, and five different configurations of FRP strip reinforcing were
tested. The walls were subjected to code-level and near-code level to determine their
behaviour at design levels. Then the walls were subjected to extreme-level records until
failure, to determine the failure modes and behaviour of the various reinforcing schemes.
It was observed from the testing that all of the strengthened specimens, regardless of
reinforcing configuration, performed well during the application of the code- and nearcode
level records. Four of the five reinforcing configurations also performed well during
application of the extreme-level record.
It was concluded from these tests that the use of vertical FRP strips is an adequate
reinforcing configuration to improve the in-plane performance of URM walls. The
behaviour of vertical strips was comparable to that of horizontal strips, which were also
tested and found to be very effective. The vertical strips were found to be effective in
repairing damaged walls. They were also found to help control the failure modes of the
specimens, and prevent collapse even after severe damage had occurred. This can be a
strong contributor to improving life-safety during a severe event.
Книги з теми "Plant fibers Testing"
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Kuzik, Marc D. Out-of-plane cyclic behavior of masonry walls reinforced externally with GFRP. Edmonton: Dept. of Civil and Environmental Engineering, University of Alberta, 1999.
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Shaibani, Aziz. Pseudoneurologic Syndromes. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190661304.003.0022.
Повний текст джерелаАнотація:
The term functional has almost replaced psychogenic in the neuromuscular literature for two reasons. It implies a disturbance of function, not structural damage; therefore, it defies laboratory testing such as MRIS, electromyography (EMG), and nerve conduction study (NCS). It is convenient to draw a parallel to the patients between migraine and brain tumors, as both cause headache, but brain MRI is negative in the former without minimizing the suffering of the patient. It is a “software” and not a “hardware” problem. It avoids irritating the patient by misunderstanding the word psychogenic which to many means “madness.”The cause of this functional impairment may fall into one of the following categories:• Conversion reaction: conversion of psychological stress to physical symptoms. This may include paralysis, hemisensory or distal sensory loss, or conversion spasms. It affects younger age groups.• Somatization: chronic multiple physical and cognitive symptoms due to chronic stress. It affects older age groups.• Factions disorder: induced real physical symptoms due to the need to be cared for, such as injecting oneself with insulin to produce hypoglycemia.• Hypochondriasis: overconcern about body functions such as suspicion of ALS due to the presence of rare fasciclutations that are normal during stress and after ingestion of a large amount of coffee. Medical students in particular are targets for this disorder.The following points are to be made on this topic. FNMD should be diagnosed by neuromuscular specialists who are trained to recognize actual syndrome whether typical or atypical. Presentations that fall out of the recognition pattern of a neuromuscular specialist, after the investigations are negative, they should be considered as FNMDs. Sometimes serial examinations are useful to confirm this suspicion. Psychatrists or psychologists are to be consulted to formulate a plan to discover the underlying stress and to treat any associated psychiatric disorder or psychological aberration. Most patients think that they are stressed due to the illness and they fail to connect the neuromuscular manifestations and the underlying stress. They offer shop around due to lack of satisfaction, especially those with somatization disorders. Some patients learn how to imitate certain conditions well, and they can deceive health care professionals. EMG and NCS are invaluable in revealing FNMD. A normal needle EMG of a weak muscles mostly indicates a central etiology (organic or functional). Normal sensory responses of a severely numb limb mean that a lesion is preganglionic (like roots avulsion, CISP, etc.) or the cause is central (a doral column lesion or functional). Management of FNMD is difficult, and many patients end up being chronic cases that wander into clinics and hospitals seeking solutions and exhausting the health care system with unnecessary expenses.It is time for these disorders to be studied in detail and be classified and have criteria set for their diagnosis so that they will not remain diagnosed only by exclusion. This chapter will describe some examples of these disorders. A video clip can tell the story better than many pages of writing. Improvement of digital cameras and electronic media has improved the diagnosis of these conditions, and it is advisable that patients record some of their symptoms when they happen. It is not uncommon for some Neuromuscular disorders (NMDs), such as myasthenia gravis (MG), small fiber neuropathy, and CISP, to be diagnosed as functional due to the lack of solid physical findings during the time of the examination. Therefore, a neuromuscular evaluation is important before these disorders are labeled as such. Some patients have genuine NMDs, but the majority of their symptoms are related to what Joseph Marsden called “sickness behavior.” A patient with carpal tunnel syndrome (CTS) may unconsciously develop numbness of the entire side of the body because he thinks that he may have a stroke.
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The First Year: Fibromyalgia: An Essential Guide for the Newly Diagnosed (First Year, The). Marlowe & Company, 2003.
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Marek, Claudia Craig, and Claudia C. Marek. First Year Fibromyalgia: Coping with Musculoskeletal Pain and Fatigue Disorder. Little, Brown Book Group Limited, 2012.
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Zydroń, Tymoteusz. Wpływ systemów korzeniowych wybranych gatunków drzew na przyrost wytrzymałości gruntu na ścinanie. Publishing House of the University of Agriculture in Krakow, 2019. http://dx.doi.org/10.15576/978-83-66602-46-5.
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The aim of the paper was to determine the influence of root systems of chosen tree species found in the Polish Flysch Carpathians on the increase of soil shear strength (root cohesion) in terms of slope stability. The paper's goal was achieved through comprehensive tests on root systems of eight relatively common in the Polish Flysch Carpathians tree species. The tests that were carried out included field work, laboratory work and analytical calculations. As part of the field work, the root area ratio (A IA) of the roots was determined using the method of profiling the walls of the trench at a distance of about 1.0 m from the tree trunk. The width of the. trenches was about 1.0 m, and their depth depended on the ground conditions and ranged from 0.6 to 1.0 m below the ground level. After preparing the walls of the trench, the profile was divided into vertical layers with a height of 0.1 m, within which root diameters were measured. Roots with diameters from 1 to 10 mm were taken into consideration in root area ratio calculations in accordance with the generally accepted methodology for this type of tests. These measurements were made in Biegnik (silver fir), Ropica Polska (silver birch, black locust) and Szymbark (silver birch, European beech, European hornbeam, silver fir, sycamore maple, Scots pine, European spruce) located near Gorlice (The Low Beskids) in areas with unplanned forest management. In case of each tested tree species the samples of roots were taken, transported to the laboratory and then saturated with water for at least one day. Before testing the samples were obtained from the water and stretched in a. tensile testing machine in order to determine their tensile strength and flexibility. In general, over 2200 root samples were tested. The results of tests on root area ratio of root systems and their tensile strength were used to determine the value of increase in shear strength of the soils, called root cohesion. To this purpose a classic Wu-Waldron calculation model was used as well as two types of bundle models, the so called static model (Fiber Bundle Model — FIRM, FBM2, FBM3) and the deformation model (Root Bundle Model— RBM1, RBM2, mRBM1) that differ in terms of the assumptions concerning the way the tensile force is distributed to the roots as well as the range of parameters taken into account during calculations. The stability analysis of 8 landslides in forest areas of Cicikowicleie and Wignickie Foothills was a form of verification of relevance of the obtained calculation results. The results of tests on root area ratio in the profile showed that, as expected, the number of roots in the soil profile and their ApIA values are very variable. It was shown that the values of the root area ratio of the tested tree species with a diameter 1-10 ram are a maximum of 0.8% close to the surface of the ground and they decrease along with the depth reaching the values at least one order of magnitude lower than close to the surface at the depth 0.5-1.0 m below the ground level. Average values of the root area ratio within the soil profile were from 0.05 to 0.13% adequately for Scots pine and European beech. The measured values of the root area ratio are relatively low in relation to the values of this parameter given in literature, which is probably connected with great cohesiveness of the soils and the fact that there were a lot of rock fragments in the soil, where the tests were carried out. Calculation results of the Gale-Grigal function indicate that a distribution of roots in the soil profile is similar for the tested species, apart from the silver fir from Bie§nik and European hornbeam. Considering the number of roots, their distribution in the soil profile and the root area ratio it appears that — considering slope stability — the root systems of European beech and black locust are the most optimal, which coincides with tests results given in literature. The results of tensile strength tests showed that the roots of the tested tree species have different tensile strength. The roots of European beech and European hornbeam had high tensile strength, whereas the roots of conifers and silver birch in deciduous trees — low. The analysis of test results also showed that the roots of the studied tree species are characterized by high variability of mechanical properties. The values Of shear strength increase are mainly related to the number and size (diameter) of the roots in the soil profile as well as their tensile strength and pullout resistance, although they can also result from the used calculation method (calculation model). The tests showed that the distribution of roots in the soil and their tensile strength are characterized by large variability, which allows the conclusion that using typical geotechnical calculations, which take into consideration the role of root systems is exposed to a high risk of overestimating their influence on the soil reinforcement. hence, while determining or assuming the increase in shear strength of soil reinforced with roots (root cohesion) for design calculations, a conservative (careful) approach that includes the most unfavourable values of this parameter should be used. Tests showed that the values of shear strength increase of the soil reinforced with roots calculated using Wu-Waldron model in extreme cases are three times higher than the values calculated using bundle models. In general, the most conservative calculation results of the shear strength increase were obtained using deformation bundle models: RBM2 (RBMw) or mRBM1. RBM2 model considers the variability of strength characteristics of soils described by Weibull survival function and in most cases gives the lowest values of the shear strength increase, which usually constitute 50% of the values of shear strength increase determined using classic Wu-Waldron model. Whereas the second model (mRBM1.) considers averaged values of roots strength parameters as well as the possibility that two main mechanism of destruction of a root bundle - rupture and pulling out - can occur at the same. time. The values of shear strength increase calculated using this model were the lowest in case of beech and hornbeam roots, which had high tensile strength. It indicates that in the surface part of the profile (down to 0.2 m below the ground level), primarily in case of deciduous trees, the main mechanism of failure of the root bundle will be pulling out. However, this model requires the knowledge of a much greater number of geometrical parameters of roots and geotechnical parameters of soil, and additionally it is very sensitive to input data. Therefore, it seems practical to use the RBM2 model to assess the influence of roots on the soil shear strength increase, and in order to obtain safe results of calculations in the surface part of the profile, the Weibull shape coefficient equal to 1.0 can be assumed. On the other hand, the Wu-Waldron model can be used for the initial assessment of the shear strength increase of soil reinforced with roots in the situation, where the deformation properties of the root system and its interaction with the soil are not considered, although the values of the shear strength increase calculated using this model should be corrected and reduced by half. Test results indicate that in terms of slope stability the root systems of beech and hornbeam have the most favourable properties - their maximum effect of soil reinforcement in the profile to the depth of 0.5 m does not usually exceed 30 kPa, and to the depth of 1 m - 20 kPa. The root systems of conifers have the least impact on the slope reinforcement, usually increasing the soil shear strength by less than 5 kPa. These values coincide to a large extent with the range of shear strength increase obtained from the direct shear test as well as results of stability analysis given in literature and carried out as part of this work. The analysis of the literature indicates that the methods of measuring tree's root systems as well as their interpretation are very different, which often limits the possibilities of comparing test results. This indicates the need to systematize this type of tests and for this purpose a root distribution model (RDM) can be used, which can be integrated with any deformation bundle model (RBM). A combination of these two calculation models allows the range of soil reinforcement around trees to be determined and this information might be used in practice, while planning bioengineering procedures in areas exposed to surface mass movements. The functionality of this solution can be increased by considering the dynamics of plant develop¬ment in the calculations. This, however, requires conducting this type of research in order to obtain more data.
Частини книг з теми "Plant fibers Testing"
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Müssig, Jürg, Holger Fischer, Nina Graupner, and Axel Drieling. "Testing Methods for Measuring Physical and Mechanical Fibre Properties (Plant and Animal Fibres)." In Industrial Applications of Natural Fibres, 267–309. Chichester, UK: John Wiley & Sons, Ltd, 2010. http://dx.doi.org/10.1002/9780470660324.ch13.
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Najeeb, Muhammad Imran, Mohamed Thariq Hameed Sultan, Ain Umaira Md Shah, and Syafiqah Nur Azrie Safri. "Drop Weight Impact Testing on Plant Fiber Reinforced Polymer Matrix: A Short Review." In Lecture Notes in Mechanical Engineering, 841–50. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0866-7_73.
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Chimenti, Dale, Stanislav Rokhlin, and Peter Nagy. "Reflection and Refraction of Waves at a Planar Composite Interface." In Physical Ultrasonics of Composites. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780195079609.003.0008.
Повний текст джерелаАнотація:
Nondestructive ultrasonic testing of composite materials is affected by several special features of wave propagation that arise from the strong anisotropy and inhomogeneity of these materials. The resulting complexity requires re-examination of old testing methodologies and development of new ones. One of the most fundamental phenomena in ultrasonic nondestructive evaluation is the reflection–refraction of ultrasonic waves at a plane interface. Even the simplest test procedure requires understanding of mode conversion and knowledge of elastic wave reflection and transmission coefficients and refraction angles. Reflection–refraction phenomena, while straightforward and well documented for isotropic materials, are much more complicated for anisotropic materials. When analyzing the oblique incidence inspection method for composite materials, one first has to address the problem of wave propagation through the interface between the coupling medium and the composite material. For example, there is an inherent fluid/composite interface in the immersion technique and a perspex/composite interface in the contact method. In the latter case, assuming that a thin fluid layer is applied to facilitate coupling through the interface, slip rather than welded boundary conditions prevail. Another example of great practical importance is the case of multidirectional fiber plies in a composite laminate, when the reflection and transmission of ultrasonic waves from one ply to another with a different orientation must be considered. Before discussing the general problem of wave refraction in anisotropic composite materials, let us review the simple isotropic case. Consider a plane interface between two isotropic elastic media in “welded” (perfectly bonded) contact, implying continuity of tractions and displacements across the interface, although the boundary conditions are not important at this point. Figure 4.1 shows a schematic diagram of a plane wave with wavenumber ki incident on the interface at angle θi. The parallel lines with spacing equal to the incident wavelength λi correspond to equal-phase planes orthogonal to the incident plane. By definition, the wavenumber ki = 2π/λi is the magnitude of the wave vector ki. The incident wave is converted at the interface into reflected and transmitted waves. The refraction angle of the transmitted wave is θr and its wavenumber is kr.
Тези доповідей конференцій з теми "Plant fibers Testing"
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SINGHAL, ANSHUL, AMY LANGHORST, MIHAELA BANU, and ALAN TAUB. "EFFECT OF ENZYMATIC RETTING CONDITIONS ON THE DIAMETER AND MECHANICAL PROPERTIES OF FLAX FIBERS." In Proceedings for the American Society for Composites-Thirty Seventh Technical Conference. Destech Publications, Inc., 2022. http://dx.doi.org/10.12783/asc37/36478.
Повний текст джерелаАнотація:
The current industrial method of extracting natural plant fibers, originally intended for their textile use, can degrade the inherent mechanical properties, making them difficult to replace e-glass fibers for reinforcement in polymer composites. Microorganisms during the initial dew/field retting step of fiber extraction process not only degrades the fiber-stem interphase bond constituting primarily pectin and lignin, but also degrades the structural components of the fiber such as cellulose, resulting in non-uniform technical fibers with poor mechanical properties. Also, current single fiber testing standards used for mechanical properties characterization of these fibers are suitable for assessing homogenous and uniform fiber properties correctly, which is not the case in natural fibers. In this study, the flax stems were treated with Pectinase Ultra SPL enzyme targeted to degrade the pectin bonds between the fibers and plant stem, without affecting the structural component cellulose. In this study, the size of technical fibers hand extracted from dew and enzyme retted flax are compared. The hand extracted enzyme retted stem fibers showed more uniform, finer diameters resulting in better tensile properties when compared with dew/field retted stem fibers. The improved properties are related to the diameter effect in which as the area of these fibers is reduced, the reduction of defects during the fiber extraction.
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Geer, Ryan, and Suyi Li. "Examining the Coiling Motion of Soft Actuators Reinforced With Tilted Helix Fibers." In ASME 2018 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/smasis2018-8038.
Повний текст джерелаАнотація:
This study aims to examine the coiling and uncoiling motion of a soft pneumatic actuator reinforced with tilted helix fibers. Coiling motion can be quite useful for robotic manipulation and locomotion purposes. This research proposes and investigates a novel actuator that is inspired and derived from the unique cell wall architecture in the seed appendage of Stork’s Bill plant (Erodium Gruinum). These plant cells are reinforced by cellulose fibers distributed in a tilted helix pattern — helixes that are tilted at a certain angle with respect to the longitudinal axis of the cell. As a result, the seed appendage can coil and uncoil via a combination of twisting and bending. This paper discusses the design, fabrication, and testing of a soft actuator that can mimic this sophisticated motion. This actuator consists of Kevlar fiber thread wrapped around a silicon rubber body that has the shape of a tube. The tube will be capped at both ends so that it can be pressurized internally to induce motion. Once the design parameter has been chosen, the soft actuator are fabricated by 1) designing and 3D printing molds, 2) tube casting and fiber wrapping, and 3) creating the end caps for pressure sealing. Carefully executing these fabrication steps is essential because any errors could give undesired deformation. Several soft actuators prototypes are fabricated based on different design choices regarding the actuator radius, tube wall thickness, and the number of tilted helix fibers (aka. fiber coverage). Proof-of-concept tests show that these actuator prototypes can indeed exhibit a combined twisting and bending under internal pressurization: all are the necessary receipts to achieve the coiling and uncoiling motion. Result of this paper can pave the way for a new family of soft actuators capable of unprecedented and sophisticated actuation motions, which are particularly appealing for soft robot application.
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Schulz, Terry L., Timothy S. Andreychek, Yong J. Song, and Kevin F. McNamee. "Westinghouse AP1000 Solution to Long-Term Cooling Debris Concerns." In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-76026.
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The AP1000 is a pressurized water reactor with passive safety features and extensive plant simplifications that provides significant and measurable improvements in safety, construction, reliability, operation, maintenance and costs. The design of the AP1000 incorporates a standard approach, which results in a plant design that can be constructed in multiple geographical regions with varying regulatory standards and expectations. The AP1000 uses proven technology, which builds on more than 2,500 reactor years of highly successful Westinghouse PWR operation. The AP1000 received Final Design Approval by the Nuclear Regulatory Commission in September 2004. The AP1000 Nuclear Power Plant uses natural recirculation of coolant to cool the core following a postulated Loss Of Coolant Accident (LOCA). Recirculation screens are provided in strategic areas of the plant to remove debris that might migrate with the water in containment and adversely affect core cooling. The approach used to avoid the potential for debris to plug the AP1000 recirculation screens is consistent with the guidance identified in Regulatory Guide 1.82 Revision 3, the Pressurized Water Reactor (PWR) Industry Guidance of NEI 04–07, and the Nuclear Regulatory Commission’s Safety Evaluation on NEI 04–07. Various contributors to screen plugging were considered, including debris that could be produced by a LOCA, resident containment debris and post accident chemical products that might be generated in the coolant pool that forms on the containment floor post-accident. The solution developed for AP1000 includes three major aspects, including the elimination of debris sources by design, features that prevent transportation of debris to the screens and the use of large advanced screen designs. Measures were taken to design out debris sources including fibers, particles and chemicals. Available industry data from walkdowns in existing plants is used to determine the characteristics and amounts of the fibrous and particulate debris that could exist in containment prior to the LOCA. Materials used in the AP1000 containment are selected to eliminate post accident chemical debris generation. Large, advanced screen designs that can tolerate significant quantities of debris have been incorporated. Testing has been performed which demonstrates that the AP1000 screens will have essentially no head loss considering the debris that could be transported to them. Testing has also been performed on an AP1000 fuel assembly that demonstrates that it will also have essentially no head loss considering the debris that could be transported to it.
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Cheng, Qingwu, Harry Adams, and Metin Yetisir. "Emergency Core Cooling System Sump Strainer Fibre Bypass Testing and Measurement." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63855.
Повний текст джерелаАнотація:
The potential of losing post-Loss Of Coolant Accident (LOCA) recirculation capability due to debris blockage of Emergency Core Cooling (ECC) strainers resulted in early replacements of ECC strainers in most nuclear power plants. To validate the performance of ECC strainers, extensive testing representing plant conditions is required. Such testing programs include thin-bed and full debris load pressure drop tests, fibre bypass tests and chemical effects tests. Multiple testing loops and state-of-the-art analysis techniques have provided in-depth understanding of sump strainer performance and the effect of chemical precipitation on debris bed head loss. ECC strainers typically use perforated plates as filtering surfaces with 1.6 to 2.5 mm holes and 35 to 40% open area, allowing some particulates and fibres to pass through the strainer filtering surfaces. Recently, the bypassed fibrous debris has been identified as a potential safety concern due to its possible deposition in the reactor core and blocking of flow into fuel assemblies. In some cases, the amount of fibre that is specified as allowed to enter a reactor core is only 15 g per fuel assembly for pressurized water reactors. Characterization and quantification of bypassed fibre debris for nuclear power plants are needed to address regulatory requirements. Testing methodology and analysis techniques to address regulatory requirements and concerns are presented in this paper. In particular, a newly developed technique is presented to address debris bypass quantification.
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BARNETT, PHILIP, JEVAN FURMANSK, JEFFREY BAUR, and DENNIS BUTCHER. "RESPONSE OF MICROVASCULAR COMPOSITES TO IN-PLANE SHEAR LOADING." In Proceedings for the American Society for Composites-Thirty Seventh Technical Conference. Destech Publications, Inc., 2022. http://dx.doi.org/10.12783/asc37/36465.
Повний текст джерелаАнотація:
Microvascular composites were manufactured with precise channel spacing aligned to and transverse to the fiber direction using a custom tool. Stainless-steel tubes and sacrificial polylactic acid were used to produce microchannels following the standard curing schedule with modification to the post-cure step. Optical and radiographic evaluation showed that the microchannels were well-aligned. Transverse microchannels yielded large resin “eyes” and voids near the channels, as well as deformed the sacrificial PLA filament, while microchannels aligned to the fibers yielded undisturbed microstructures with circular cross-section channels. In-plane shear testing revealed that transverse microchannels cause a disturbance in the stress state of the composites when subjected to shear loading. Channels aligned to the fibers failed at the microchannels, though their penalty to the shear properties was small. This study shows that the shear properties of microvascular composites are comparable to those of neat composites, allowing for the addition of multifunctionality with little penalty.
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Dharani, L. R., and S. B. Haug. "Transverse Fracture Toughness of Unidirectional Continuous Fiber and Hybrid Ceramic Matrix Composites." In ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-1158.
Повний текст джерелаАнотація:
Abstract Reinforcing ceramic materials with unidirectionally aligned continuous fibers improves the mechanical characteristics in the fiber direction but often results in reduced transverse strength and fracture toughness. As an effort to improve the transverse properties of unidirectional fiber reinforecd ceramic matrix composites (FCMC), randomly dispersed fine whiskers can be added to the matrix. The result is a hybrid ceramic matrix composite (HCMC). The objective of this investigation was to ascertain what improvement, if any, can be made through the process of hybridization. The constituent materials evaluated in this study include cordierite (magnesia-alumino-silicate) for the matrix, silicon carbide continuous fiber tow and silicon carbide whiskers. Specimens were fabricated using filament/slurry winding followed by hot press sintering. The specimen bar lengths ranged from 30 to 35 millimeters and had nominally square cross-sections of 4 millimeters. Three-point chevron-notched flexural testing was performed using an MTS-810 servo-hydraulic system. The method presented is based on that which was provided by S-X Wu in ASTM STP 855. The difference here is that a numerical solution is used instead of calibrating fitted stress intensity coefficient curves to the geometry of a material with a well established fracture toughness. The primary advantage to using the cheveron notch profile is that the high stress concentration at the tip of the cheveron ligament induces crack initiation at low loads. As the crack progresses into the increasingly wider portion of the chevron it experiences a decreasing stress intensity field and grows in a stabile fashion as the load is increased. A second advantage is that the stress intensity as a function of crack length is well defined and reaches a minimum at the critical crack length. The need for pre-cracking and the knowledge of the critical crack length are thus avoided. The plane strain opening mode fracture toughness can be determined from specimen geometry, maximum load and flexural span alone. The results from testing confirmed the chevron-notched three-point-bend test produced limited but stable crack growth prior to failure without the introduction of a starting precrack. Instant failure due to crack initiation overload and the resulting potential over-estimate of the transverse plane strain opening mode fracture toughness was avoided. The method presented successfully reproduced the results obtain using other means. The fracture toughness of monolithic cordierite was found to be within 1% of the value published in the Ceramic Source, v8. Substantial improvement to the transverse fracture toughness of a continuous fiber reinforced ceramic matrix composite through the introduction of whiskers to the matrix was demonstrated. When compared with FCMCs with the same base matrix and approximately the same volume fraction of fibers, the HCMCs evaluated in this study displayed a 99% increase in fracture toughness for a crack propagating along the fiber direction and an 82% increase for a crack propagating across the fibers. A significantly greater amount of damage was observed on the fracture surface of the hybrid composite. This indicates more crack deflection and branching due to the presence of the whiskers occurred in the hybrid during fracture. The transverse fracture toughness that results from a crack progressing along the fiber direction was considerably higher than that resulting from a crack propagating across the fiber. More broken fibers were seen on the fracture surfaces of the former. The energy required to break fibers and peal fibers away from the matrix may be responsible for the greater fracture toughness found for a crack propagating in the plane along the fiber direction. Improved load transfer provided by the whiskers in the matrix may aid in the resistance to fiber pealing.
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Balaji, M. A. Sai, Eakambaram Arumugam, P. Baskara Sethupathi, S. Habib Rahmathulla, and H. Sultan Navid. "The Effect of Chopped Steel Fibre Orientation on Frictional Properties in a Phenolic Resin-based Asbestos-free Semimetallic Friction Material." In EuroBrake 2021. FISITA, 2021. http://dx.doi.org/10.46720/8511493eb2021-mds-004.
Повний текст джерелаАнотація:
The effect of directional orientation of Chopped steel wool fiber in a friction material matrix / Brake pads that influences Friction, Wear and Mechanical properties of the Brake pads have been evaluated in a phenolic resin-based asbestos-free semi-metallic friction material composition. </p><p>Brake pad compositions widely use chopped steel wool fibers having a nominal length of less than 10 mm; diameter of about 500 microns; carbon content between 0.05 – 0.15 % as reinforcement. During compounding and mixing of friction material formulation, chopped Steel wool fibers along with dozen other raw materials are mixed/homogenized using plough shear mixer resulting in the steel fibers dispersed and oriented randomly in different plan and direction in the mixture and so over the final brake pad matrix too. </p><p>Trials have been carried out in Fricmart’s prototype Lab to orient chopped steel wool fiber in an uni directional plan in various semi-metallic formulations and progress has been achieved only in a medium- steel brake pad formulation that contains about 25% chopped steel fibers. Fricmart’s S-428 grade Steel wool fiber conforming to the above said specification has been used in the experiments. Fibers were initially classified using a set of sieves to remove the fines having diameter and length less than 200 microns and 3 mm respectively to meet the desired loose density / bulk density limit of 0.55 – 0.70 gm/cc to support the process of orientation. Further, a brake pad model that has rectangular geometry ( Merc. W-123 Pad) with an area of about 50 sq. cm was chosen to conduct the trials and to support the process of orientation. Brake pads were molded using conventional compression molding process at temp. of 150 deg. C with specific pressure of 250 bar and 6 minutes curing followed by 4 hours step curing ( post-baking ) to max. temp. of 180 deg. C in an air oven . Preparation of Samples: Sample 1 -By employing bi-directional magnetic field coupled with other special charging chute and dispersing techniques, the desired orientation of chopped steel wool fiber that was targeted to be parallel to the sliding direction of the brake (pad) was achieved to a level of more than 90% evenly oriented throughout the layer and matrix of the brake pad. Fricmart’s PLM – Stereo Microscope surveillance facility is used to ascertain percentage orientation during trials. Sample - 2: Brake pads processed as above by “parallel orientation to sliding direction’’ have later been used to study the effect of “orientation in perpendicular to the sliding direction’’ just by “inverting the new sample” specimen at the time of testing. Sample - 3: One set of brake pads were processed as per industries standard using the same batch/composition of raw materials with a random distribution of chopped steel wool fiber under identical process condition without carrying out directional orientation. Testing & Evaluation:The samples were cut from the brake pad and tested in Chase Type Friction Tester as per SAE J661 – small sample testing and the following are the observations. Internal shear measured as per ISO 6311 of sample -1 was significantly higher than sample – 2 & least in the case of sample 3 Faster bedding or faster adaptability to the disc in case of the sample- 1. 80% bedding achieved within 10 minutes of burnishing as compared to 20 minutes in case of samples- 2 & 3. The coefficient of friction is also dependent on the fiber orientation and µ for the developed pad ranges between 0.35 and 0.40. Fade resistance for samples 1 & 2 is superior when compared to sample 3.</p><p>Further, it was observed that as temperature increases, initially there was abrasion/plowing and on a further rise in temperature, a transfer film was developed making the steady-state friction. The wear rates decreased if the sliding path/direction changes from parallel to the perpendicular direction. The worn surface morphology was studied using FESEM and found that wear resistance is found to relate to the stability of the developed film. Sample 1 with the fibers oriented parallel to the sliding direction exhibited smoother running whereas sample 2 created undesirable judder noise. Hence it can be concluded that the Orientation of fibers with respect to sliding direction is preferable to the randomly oriented fibers towards frictional characteristics.
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Carr, Kevin, Robert Greer, Marvin B. May, and Scott Gift. "Navy testing of the iXBlue MARINS Fiber Optic Gyroscope (FOG) Inertial Navigation system (INS)." In 2014 IEEE/ION Position, Location and Navigation Symposium - PLANS 2014. IEEE, 2014. http://dx.doi.org/10.1109/plans.2014.6851515.
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Tiano, Thomas, Margaret Roylance, Benjamin Harrison, and Richard Czerw. "Intralaminar Reinforcement for Biomimetic Toughening of Bismaleimide Composites Using Nanostructured Materials." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81689.
Повний текст джерелаАнотація:
Many conventional composite materials are composed of multiple layers of continuous fiber reinforced resin produced by lamination of b-staged prepreg and subsequent cure. These materials exhibit very high strength and stiffness in the plane, dominated by the properties of the fibers. The Achilles heel of such composites is the interlaminar strength, which is dependent on the strength of the unreinforced resin, often leading to failure by delamination under load. Current methods for increasing the interlaminar shear strength of composites consist of inserting translaminar reinforcement fibers through the entire thickness of a laminated composite, such as z-pin technology developed by Foster-Miller [1]. While effective, this technique adds several processing steps, including ultrasonic insertion of the z-pins into the laminate, subsequently causing a significant cost increase to laminated composites. Described in this paper is a process utilizing single-walled carbon nanotubes (SWNTs) and vapor grown carbon nanofibers as reinforcing elements promoting interlaminar shear strength and toughness in carbon fiber/bismaleimide (BMI) resin composites. The resulting composites mimic the natural reinforcing mechanism utilized in insect cuticles. Three different methods of increasing the affinity of these carbon nanofillers for the BMI matrix were explored. The mechanical properties of these composites were assessed using end notch flexure testing. The results indicated that including nanofiller at the laminae interface could increase the interlaminar shear strength of carbon fiber/BMI composites by up to 58%. SEM micrographs revealed that the nanofiller successfully bridged the laminae of the composite, thus biomimicking the insect cuticle. Composite fabrication techniques developed on this program would have a wide variety of applications in space and aerospace structures including leading and trailing edges of aircraft wings.
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Tuttle, Sarah E., Emily Farr, Claire L. Poppett, Colby A. Jurgenson, José Sánchez-Gallego, Debra A. Fischer, Ryan Petersburg, Richard W. Pogge, and Juna A. Kollmeier. "Testing fiber tapers for use in the SDSS-V focal plane system." In Ground-based and Airborne Instrumentation for Astronomy VIII, edited by Christopher J. Evans, Julia J. Bryant, and Kentaro Motohara. SPIE, 2020. http://dx.doi.org/10.1117/12.2562293.
Повний текст джерелаЗвіти організацій з теми "Plant fibers Testing"
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Granot, David, Scott Holaday, and Randy D. Allen. Enhancing Cotton Fiber Elongation and Cellulose Synthesis by Manipulating Fructokinase Activity. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7613878.bard.
Повний текст джерелаАнотація:
a. Objectives (a) Identification and characterization of the cotton fiber FRKs; (b) Generating transgenic cotton plants overproducing either substrate inhibited tomato FRK or tomato FRK without substrate inhibition; (c) Generating transgenic cotton plants with RNAi suppression of fiber expressed FRKs; (d) Generating Arabidopsis plants that over express FRK1, FRK2, or both genes, as additional means to assess the contribution of FRK to cellulose synthesis and biomass production. b. Background to the topic: Cellulose synthesis and fiber elongation are dependent on sugar metabolism. Previous results suggested that FRKs (fructokinase enzymes that specifically phosphorylate fructose) are major players in sugar metabolism and cellulose synthesis. We therefore hypothesized that increasing fructose phosphorylation may enhance fiber elongation and cellulose synthesis in cotton plants. Accordinlgy, the objectives of this research were: c. Major conclusions and achievements: Two cotton FRKs expressed in fibers, GhFRK2 and GhFRK3, were cloned and characterized. We found that GhFRK2 enzyme is located in the cytosol and GhFRK3 is located within plastids. Both enzymes enable growth on fructose (but not on glucose) of hexose kinase deficient yeast strain, confirming the fructokinase activity of the cloned genes. RNAi constructs with each gene were prepared and sent to the US collaborator to generate cotton plants with RNAi suppression of these genes. To examine the effect of FRKs using Arabidopsis plants we generated transgenic plants expressing either LeFRK1 or LeFRK2 at high level. No visible phenotype has been observed. Yet, plants expressing both genes simultaneously are being created and will be tested. To test our hypothesis that increasing fructose phosphorylation may enhance fiber cellulose synthesis, we generated twenty independent transgenic cotton plant lines overexpressing Lycopersicon (Le) FRK1. Transgene expression was high in leaves and moderate in developing fiber, but enhanced FRK activity in fibers was inconsistent between experiments. Some lines exhibited a 9-11% enhancement of fiber length or strength, but only one line tested had consistent improvement in fiber strength that correlated with elevated FRK activity in the fibers. However, in one experiment, seed cotton mass was improved in all transgenic lines and correlated with enhanced FRK activity in fibers. When greenhouse plants were subjected to severe drought during flowering and boll development, no genotypic differences in fiber quality were noted. Seed cotton mass was improved for two transgenic lines but did not correlate with fiber FRK activity. We conclude that LeFRK1 over-expression in fibers has only a small effect on fiber quality, and any positive effects depend on optimum conditions. The improvement in productivity for greenhouse plants may have been due to better structural development of the water-conducting tissue (xylem) of the stem, since stem diameters were larger for some lines and the activity of FRK in the outer xylem greater than observed for wild-type plants. We are testing this idea and developing other transgenic cotton plants to understand the roles of FRK in fiber and xylem development. We see the potential to develop a cotton plant with improved stem strength and productivity under drought for windy, semi-arid regions where cotton is grown. d. Implications, scientific and agricultural: FRKs are probably bottle neck enzymes for biomass and wood synthesis and their increased expression has the potential to enhance wood and biomass production, not only in cotton plants but also in other feed and energy renewable plants.
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Lerman, Micheal W., Douglas S. Cairns, and Jared W. Nelson. Investigation of the Effect of In-Plane Fiber Waviness in Composite Materials through Multiple Scales of Testing and Finite Element Modeling. Office of Scientific and Technical Information (OSTI), January 2017. http://dx.doi.org/10.2172/1505394.
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