Dissertations / Theses on the topic 'Low temperature storage assay'
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Hudson, G. "Micropropagation and low temperature storage of Dieffenbachia." Thesis, University of East London, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370763.
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Wilson, Ian D. "Gene expression during low temperature storage of pears." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303152.
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Phillips, Lisa Elaine. "The effect of low temperature on Salmonella." Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286534.
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Lee, Sookha. "Low-temperature damp corn storage with and without chemical preservatives." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0029/MQ47341.pdf.
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Brown, Claire. "Low temperature storage and cryopreservation of hoverflies as biological control agents." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246695.
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Hsu, Chuan-liang. "Influence of cooling rate on glass transition temperature and starch retrogradation during low temperature storage /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9924889.
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Augood, P. C. "Low-Temperature Thermal-Energy Storage and Transmission Systems Employing Hydrophilic Polymeric Materials." Thesis, Cranfield University, 1997. http://hdl.handle.net/1826/4517.
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The wide fluctuations that occur in the aggregate electrical demand of a generating
utility are punitive with respect to total system efficiency. Demand side management
techniques have been applied to reduce such fluctuations including the conversion of
electrical energy to thermal energy during periods of low demand for use during peak
demand periods. For thermal processes requiring energy above ambient temperature it
is feasible to use sensible heat due to the existence of stable storage mediums and
efficient methods of heating at the high temperatures required. However where energy
is required below ambient temperatures, efficiency of cooling limits the use of sensible
heat, hence latent heat storage has been adopted. Conventional cold storage systems use
ice banks to store cooling energy at 0°C in order to capture the high latent heat of
fusion of water. The rate of discharge for such stores is limited by thermal resistance in
the store and the thermal capacity of secondary coolants (such as glycol solutions).
This investigated the use of hydrophilic materials to overcome the limitations of
current cold-storage technology. Such materials have the capacity to absorb and retain
up to 95% by mass of water (or other aqueous solutions) regardless of how the
materials is subdivided. Furthermore the thermal properties of the polymers in their
hydrated state resemble those of the free hydration fluid, including any phase
transitions. By supporting the hydrated materials in a non-freeing, non-aqueous fluid
the resultant mixture provides a medium for cold storage that can be pumped and used
at the point of load, and is not limited by the thermal resistance of an encapsulating
material.
Three aspects concerning the utilisation of hydrophilic materials for thermal
engineering applications have been investigated; (i) the physical properties of the
materials
in their hydrated state, (ii) methods of fluidising material in a high density
store, and (iii) the heat transfer properties of hydrophilic based slurries while
undergoing phase transition.
Material tests have shown that currently available hydrophilic materials have thermo-
physical properties that depend principally upon the hydrating fluid, regardless of
particle size, and are stable over long periods (>3years). Suitable hydration fluids can
lower the temperature of the phase transition thus extending their potential as storage
mediums beyond those of ice-based technologies. Novel materials, of very high water
content (95%) have been produced and investigated. These appear to be very suitable
for thermal storage because they increase the maximum achievable energy densities of
a fluidised storage system and potentially reduce cost.
A number of thermal storage devices to utilise hydrophilic based slurries have been
designed and evaluated. The resultant devices has been shown to provide a means of
taking hydrophilic materials to, and from, a packed bed and feeding them at a
controlled rate into a fluid stream. The thermal charge/discharge rates of such a device
are limited only by the choice of external heat exchange systems. An experimental apparatus has been designed to investigate the effects of phase change
particles on the heat transfer properties of flowing mixtures. The results have shown
that (i) at temperatures above the phase transition temperature the presence of the
particles causes an increase in the measured heat transfer coefficient for concentrations
above 10% by volume, (ii) there is a significant interaction of particles at the heat
transfer surface, and (iii) that under high flow rate conditions, with phase change
occurring, heat transfer coefficients are considerably enhanced (ie 80%) above those of
the support fluid when used alone or with non-active particles.
Further work is recommended to extend this study to produce an engineering prototype
storage system for trial evaluation.
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Jones, Samantha. "Ceria Based Catalysts for Low Temperature NOx Storage and Release." UKnowledge, 2016. http://uknowledge.uky.edu/chemistry_etds/67.
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Model ceria catalysts were evaluated for NOx storage and desorption performance under lean conditions. Three different storage temperatures (80 °C, 120 °C, and 160 °C) were utilized to evaluate NOx storage. Higher temperatures resulted in higher NOx storage. It was observed that storage of platinum promoted ceria resulted in higher NOx storage compared to promotion with palladium. NOx desorption behavior of platinum promoted ceria indicated that the majority of NOx is released at high temperatures (> 350 °C), comparatively palladium promotion released more of the stored NOx at lower temperatures. Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) indicated that platinum promotion results in NOx storage as thermally stabile nitrates, while palladium promotion results in NOx storage as thermally labile nitrites.
Doping ceria with trivalent rare earth oxides has been shown to improve NOx storage by generating lattice oxygen vacancies. Ceria doped with Pr, Y, La, Sm, and Nd at two different concentrations (5 and 20 mol%) and promoted with Pt were evaluated. Doping ceria with 5% Sm, Nd, and Pr improved the amount of NOx stored while the addition of Sm and La did not improve storage. Upon increasing dopant concentration, NOx storage decreased in all cases but Pr. However, increasing Pr concentration was found to increase NOx storage as well as low temperature NOx release. Ceria doped with Pr promoted with Pd increased the amount of NOx released at lower temperatures compared to Pt promotion, although palladium promotion resulted in lower storage. Similar DRIFTS spectra were obtained with Ce-Pr when promoted with Pt or Pd compared to model catalysts. Platinum promotion results in the storage of NOx at nitrates, which require high temperatures for removal. Comparatively, Pd promotion results in NOx stored at nitrites requiring lower temperatures for removal.
Ceria doped with Pr proved to be promising, although not thermally stable when exposed to high temperatures as may be seen during a DPF clean up. Therefor, stabilizing Ce-Pr catalysts with Zr were evaluated. It was found that stabilizing Ce-Pr with Zr was not found to be beneficial to the catalyst performance.
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Ntsendwana, Bulelwa. "Advanced low temperature metal hydride materials for low temperature proton exchange membrane fuel cell application." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8494_1307431585.
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Energy is one of the basic needs of human beings and is extremely crucial for continued development of human life. Our work, leisure and our economic, social and physical welfare all depend on the sufficient, uninterrupted supply of energy. Therefore, it is essential to provide adequate and affordable energy for improving human welfare and raising living standards. Global concern over environmental climate change linked to fossil fuel consumption has increased pressure to generate power from renewable sources [1]. Although substantial advances in renewable energy technologies have been made, significant challenges remain in developing integrated renewable energy systems due primarily to mismatch between load demand and source capabilities [2]. The output from renewable energy sources such as photo-voltaic, wind, tidal, and micro-hydro fluctuate on an hourly, daily, and seasonal basis. As a result, these devices are not well suited for directly powering loads that require a uniform and uninterrupted supply of input energy.
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Rossi, Espagnet Alberto. "Techno-Economic Assessment of Thermal Energy Storage integration into Low Temperature District Heating Networks." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-191485.
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Thermal energy storage (TES) systems are technologies with the potential to enhance the efficiency and the flexibility of the coming 4th generation low temperature district heating (LTDH). Their integration would enable the creation of smarter, more efficient networks, benefiting both the utilities and the end consumers. This study aims at developing a comparative assessment of TES systems, both latent and sensible heat based. First, a techno-economic analysis of several TES systems is conducted to evaluate their suitability to be integrated into LTDH. Then, potential scenarios of TES integration are proposed and analysed in a case study of an active LTDH network. This is complemented with a review of current DH legislation focused on the Swedish case, with the aim of taking into consideration the present situation, and changes that may support some technologies over others. The results of the analysis show that sensible heat storage is still preferred to latent heat when coupled with LTDH: the cost per kWh stored is still 15% higher, at least, for latent heat in systems below 5MWh of storage size; though, they require just half of the volume. However, it is expected that the cost of latent heat storage systems will decline in the future, making them more competitive. From a system perspective, the introduction of TES systems into the network results in an increase in flexibility leading to lower heat production costs by load shifting. It is achieved by running the production units with lower marginal heat production costs for longer periods and with higher efficiency, and thus reducing the operating hours of the other more expensive operating units during peak load conditions. In the case study, savings in the magnitude of 0.5k EUR/year are achieved through this operational strategy, with an investment cost of 2k EUR to purchase a water tank. These results may also be extended to the case when heat generation is replaced by renewable, intermittent energy sources; thus increasing profits, reducing fuel consumption, and consequently emissions. This study represents a step forward in the development of a more efficient DH system through the integration of TES, which will play a crucial role in future smart energy system.Thermal energy storage (TES) eller Termisk energilagring är en teknologi med potentialen att öka effektivitet och flexibilitet i den kommande fjärde generationens fjärrvärme (LTDH). Studien har som mål att kartlägga en komparativ uppskattning av TES systemen, baserad både på latent och sensibel värme. Resultaten visar att lagring av sensibel värme är att föredra före latent värme när den kopplas med LTDH: pris per lagrade kWh kvarstår som 15% högre än för latent värme i system under 5 MWh av lagringsutrymme; dock fordrar de endast hälften av volymen. Utifrån systemperspektiv innebär introduktionen av TES system i nätverket en ökning av flexibilitet vilket leder till reducerade värmeproduktionskostnaderna i mindre belastning. I fallstudien nås en sparnivå av femhundra euro per år genom denna operativa strategi, med en investering av 2000 euro för inköp av vattentank. Resultaten kan också vidgas till en situation där värmeproduktionen ersätts av förnybara, intermittenta energikällor; till detta medföljer högre vinster, lägre bruk av bränsle vilket skulle innebära lägre utsläpp. Studien kan ses som ett steg framåt mot skapandet av en mer effektiv DH system genom integrationen av TES, vilket kommer att spela en betydande roll i framtida smarta energisystem.
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Chin, Yee Sing. "Impacts of fuel inventory on low temperature ignition risk during handling and storage of biomass." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/18253/.
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As modernisation takes place, fossil fuel burning is one of the quickest ways to meet the ever rising energy demand. The increasing emissions of greenhouse gases, particularly carbon dioxide, as a result of excessive fossil fuel burning had been blamed for global climate change. Vegetation-based biomass is a form of bioenergy and a recognised solid renewable fuel with potential to replace coal in combating anthropogenic climate change in the power generation sector. Nevertheless, it is not a straight forward case for biomass to replace coal since biomass is an extremely reactive fuel prone to self-heating leading to self-ignition. Spontaneous biomass ignition leading to disastrous fires during biomass handling and storage could be avoided if the causes of biomass low temperature ignition are well understood. Detailed studies on woody and herbaceous biomass fuels commonly used in UK power stations were examined according to several British Standards. On top of characterising all the biomass samples, BS EN 50281-2-1 and BS EN 15188 were adhered to specifically in investigating low temperature ignition during biomass handling and biomass storage respectively. Many power stations use a mix of different biomass in their fuel inventories which can lead to dusts of biomass mixtures. Thus the low temperature ignition characteristics of biomass blends have been studied. Other factors that may impact on ignition risks are binders (added to give strength to briquettes or pellets) and pretreatments (washing and torrefaction). Washing aims to improve ash properties towards the end of combustion process while torrefaction is used to increase the calorific value of biomass that is naturally lower than fossil fuels. The reaction kinetics of some biomass dust layers deposited on a constant temperature hot surface and corresponding ignition delay time were estimated mathematically. Results from minimum dust layer ignition temperature determination showed that all biomass, regardless of woody or herbaceous, with or without binder, before or after pre-treatments, had critically ignited within a very small temperature range. This was consistent with the results of self-ignition propensity risk ranking that concluded that biomass possess medium-high risk of self-igniting. An exception to this is torrefied biomass which had not sustained a much higher temperature before it critically ignited as compared with the untreated counterpart; unlike many anticipations and therefore, the low temperature ignition characteristics were discussed from many other aspects, mainly on the reduced particle size or dust layer density. For biomass storage, scaling up method and Frank-Kamenetskii method derived from Thermal Explosion Theory had been applied to forecast the critical ignition temperature and ignition delay time for large-scale industrial storage from smaller laboratory scale experiments. Non-negligible error was detected when extrapolating to industrial volume especially for the ignition delay time and appropriate recommendation was made as a possible remedy. Emissions when biomass smouldered and critically ignited that happened at 10˚C apart were examined with a three-stage emission sampling and compared, with the aims of obtaining a suitable biomass self-ignition indicator. Detailed studies were required since only one organic compound was detected to be consistently different between smouldering and critically-igniting biomass dust. Within this small temperature difference, different volatile species with respective intensities had been modelled with FG-BioMass software. Towards the end of this work, conclusions were drawn for each section and suggestion of combining both pre-treatments with binder addition were recommended for further studies. The work in the thesis provides a large data-set which will help inform power plant operators in their dust management risks. The laboratory-scale experiments give a useful risk-ranking for dust layer ignition, but uncertainties in ignition-delay times, especially for large biomass quantities, indicate that improvements are required to BS EN 15188 (biomass storage test) to enable scaling-up with more certainty.
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Craddock, David M. "A FORTRAN 77 simulation of a low temperature storage freezer utilizing a non-azeotropic refrigerant blend." Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1179341435.
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Khan, Mohd Azam Khan bin Goriman. "Studies on capacitation and the effects of cooling and low temperature storage on stallion sperm function." Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244254.
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Najiba, Shah. "High Pressure and Low Temperature Study of Ammonia Borane and Lithium Amidoborane." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1388.
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Hydrogen has been considered as a potentially efficient and environmentally friendly alternative energy solution. However, one of the most important scientific and technical challenges that the “hydrogen economy” faces is the development of safe and economically viable on-board hydrogen storage for fuel cell applications, especially to the transportation sector. Ammonia borane (BH3NH3), a solid state hydrogen storage material, possesses exceptionally high hydrogen content (19.6 wt%).However, a fairly high temperature is required to release all the hydrogen atoms, along with the emission of toxic borazine. Recently research interests are focusing on the improvement of H2 discharge from ammonia borane (AB) including lowering the dehydrogenation temperature and enhancing hydrogen release rate using different techniques. Till now the detailed information about the bonding characteristics of AB is not sufficient to understand details about its phases and structures.
Elemental substitution of ammonia borane produces metal amidoboranes. Introduction of metal atoms to the ammonia borane structure may alter the bonding characteristics. Lithium amidoborane is synthesized by ball milling of ammonia borane and lithium hydride. High pressure study of molecular crystal provides unique insight into the intermolecular bonding forces and phase stability. During this dissertation, Raman spectroscopic study of lithium amidoborane has been carried out at high pressure in a diamond anvil cell. It has been identified that there is no dihydrogen bond in the lithium amidoborane structure, whereas dihydrogen bond is the characteristic bond of the parent compound ammonia borane. It has also been identified that the B-H bond becomes weaker, whereas B-N and N-H bonds become stronger than those in the parent compound ammonia borane. At high pressure up to 15 GPa, Raman spectroscopic study indicates two phase transformations of lithium amidoborane, whereas synchrotron X-ray diffraction data indicates only one phase transformation of this material.
Pressure and temperature has a significant effect on the structural stability of ammonia borane. This dissertation explored the phase transformation behavior of ammonia borane at high pressure and low temperature using in situ Raman spectroscopy. The P-T phase boundary between the tetragonal (I4mm) and orthorhombic (Pmn21) phases of ammonia borane has been determined. The transition has a positive Clapeyron slope which indicates the transition is of exothermic in nature. Influence of nanoconfinemment on the I4mm to Pmn21 phase transition of ammonia borane was also investigated. Mesoporus silica scaffolds SBA-15 with pore size of ~8 nm and MCM-41 with pore size of 2.1-2.7 nm, were used to nanoconfine ammonia borane. During cooling down, the I4mm to Pmn21 phase transition was not observed in MCM-41 nanoconfined ammonia borane, whereas the SBA-15 nanocondfined ammonia borane shows the phase transition at ~195 K. Four new phases of ammonia borane were also identified at high pressure up to 15 GPa and low temperature down to 90 K.
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Manap, Mohd Yazid B. Hj Abd. "The effects of low temperature storage and thermisation on the quality of raw and heat treated milk." Thesis, University of Glasgow, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385626.
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Belaid, Ashur Belaid. "A six-chamber medium-to-high temperature refrigeration system for laboratory purposes." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2522.
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Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2017.Food and water fuel and sustain life on earth. Since ancient times, their sourcing and preservation have been very important issues to humanity. In modern times, experimentation is a major step in analysing how cold storage problems in the medical and food science technology fields can be addressed. For investigating spoilage of new products and/or growth of pathogens in such cases, it is necessary to do experiments at different low temperatures for prolonged periods and check the effects. While this can be undertaken in a conventional two chambers fridge, it takes a long time to investigate a whole range of feasible storage temperatures. This dissertation describes work intended to treble the samples in such investigations and, therefore, significantly reduce the times. Six well- insulated chambers were constructed from plastic and wood and set at different temperatures. An ordinary deep freezer was used as the main heat sink for the chambers. Experiments were done with different methods to get the best result for the cold air flow into the chambers over period of eight months. The chambers temperatures were set between 0 and 15°C. It was finally established that a properly-designed six-chamber system could successfully be added to an ordinary freezer to provide different medium-to-high refrigeration temperatures without the use of a multi-pressure refrigeration cycle.
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Spalholz, Hans. "Development of Short Term Storage Techniques for Grafted Vegetable Seedlings." Thesis, The University of Arizona, 2013. http://hdl.handle.net/10150/293734.
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Vegetable grafting confers soil-borne disease resistance through the use of selected rootstocks. Additional costs associated with grafted vegetable seedling propagation limit grower access to this technology. The use of low temperature storage in grafted seedling production reduces labor costs and allows propagators to meet the seasonal and narrow-window demand of growers. For the first part of the experiment 22 genotypes of Solanaceae or Cucurbitaceae seedlings were evaluated in low temperature storage conditions (5 or 12°C). Seedling performance was better in 12°C storage than in 5°C storage. For the second part of the experiment watermelon, the most low-temperature sensitive species found in our first study, was grafted onto two different commercial rootstocks or on to other watermelon seedlings and stored at 12°C for two and four weeks. Both 'Strong Tosa' and 'Emphasis' rootstocks conferred chilling tolerance during storage to watermelon scions, allowing storage of grafted plants for two weeks.
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Zhou, Quan, Zongbin Zhao, Zhiyu Wang, Yanfeng Dong, Xuzhen Wang, Yury Gogotsi, and Jieshan Qiu. "Low temperature plasma synthesis of mesoporous Fe₃O₄ nanorods grafted on reduced graphene oxide for high performance lithium storage." Royal Society of Chemistry, 2014. https://tud.qucosa.de/id/qucosa%3A36296.
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Transition metal oxide coupling with carbon is an effective method for improving electrical conductivity of battery electrodes and avoiding the degradation of their lithium storage capability due to large volume expansion/contraction and severe particle aggregation during the lithium insertion and desertion process. In our present work, we develop an effective approach to fabricate the nanocomposites of porous rod-shaped Fe₃O₄ anchored on reduced graphene oxide (Fe₃O₄/rGO) by controlling the in situ nucleation and growth of β-FeOOH onto the graphene oxide (β-FeOOH/GO) and followed by dielectric barrier discharge (DBD) hydrogen plasma treatment. Such well-designed hierarchical nanostructures are beneficial for maximum utilization of electrochemically active matter in lithium ion batteries and display superior Li uptake with high reversible capacity, good rate capability, and excellent stability, maintaining 890 mA h g⁻¹ capacity over 100 cycles at a current density of 500 mA g⁻¹.
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Raut, Prasad S. "Towards Development Of Polymeric Compounds For Energy Storage Devices And For Low Energy Loss Tires." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1493947416353888.
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Keskin, Mehmet Yigit. "Studies on the incidence of Dekkera bruxellensis in Turkish wines and effect of low temperatures on 4-ethylphenol production." Master's thesis, ISA/UL, 2012. http://hdl.handle.net/10400.5/8596.
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Mestrado Vinifera EuroMaster - Instituto Superior de AgronomiaBrettanomyces/Dekkera bruxellensis has the ability to produce significant amounts of 4-ethylphenol (4-EP) and cause important organoleptic defects in affected wines. In this work we investigated the incidence of B. bruxellensis and of 4-ethylphenol in Turkish red wines randomly collected at winery facilities. Among 40 samples, this species was only recovered from one sample aged in oak barrels. In 4 samples, culturable population was not found but the 4-EP concentration indicated previous Dekkera bruxellensis activity. Thus, following potential Brettanomyces-sourced aroma impacts in wine using 4-Ethylphenol and 4-Ethylguaiacol concentrations as proxies should only be considered reliable at analyte levels >100 μg/l (Rayne and Eggers, 2007). Furthermore, we studied the influence of storage temperature on the production of 4-EP by wild of D. bruxellensis in 3 different Portuguese red wines. Temperatures of 10 ºC and 15ºC were not effective in preventive the increase of 4-EP over 600 μg/l during 90 days. At 3 ºC one sample showed similar 4-EP increase while in two other samples its concentration was kept unchanged. Production of 4-EP at 3ºC and 10ºC was confirmed when the strain TR 26 was incubated in red wine for 49 days. However, the total amount of 4-EP produced was below 150 μg/l while at 15ºC and 20ºC the values reached 1600 μg/l. Therefore, the effect of low temperatures acts by delaying microbial growth which results in lower concentrations of 4-EP but once temperature increases 4-EP production is readily stimulated
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Lopes, Telma Sofia Risso. "Advantages and drawbacks of a linear focusing system with low melting point molten salts." Master's thesis, Universidade de Évora, 2019. http://hdl.handle.net/10174/31058.
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Parabolic trough power plants have been the most commercially implemented solar thermal electricity plants in the world. As such, several studies have been carried out over the last years in order to improve the efficiency/reduce the costs of this type of plants. From here it came the possibility of using the salts, that are currently used in this type of plants as storage fluid only, as heat transfer fluid (HTF). Its use as HTF seems to be a viable solution, however its implementation requires careful analysis. The project that gave rise to this dissertation aims to study this feasibility. During this work, the advantages and disadvantages of the salts in relation to the thermal oils (HTF currently used in this type of installations) will be presented and demonstrated, and SAM simulations will be performed to analyse the performance of a platform with the different fluids. Finally, the changes caused in the LCOE as well as in the power block design and efficiency will be determined; Resumo:
VANTAGENS E DESVANTAGENS DOS SAIS FUNDIDOS DE BAIXO PONTO DE FUSÃO NUM SISTEMA DE FOCO LINEAR
As centrais lineares de coletores cilíndrico-parabólicos são atualmente a tecnologia de geração solar termoelétrica mais utilizada em todo o mundo. Como tal, vários estudos têm vindo a ser realizados ao longo dos últimos anos com o intuito de melhorar a eficiência/reduzir os custos deste tipo de plantas. Daqui surgiu a possibilidade de utilizar os sais fundidos, já utilizados neste tipo de plantas apenas como fluido de armazenamento, também como fluido de transferência de calor (HTF). A sua utilização como HTF parece ser uma solução viável, no entanto a sua implementação requer uma análise cuidada. O projeto que deu origem a esta dissertação tem como objetivo estudar essa viabilidade. Ao longo deste trabalho serão apresentadas e demonstradas as vantagens e desvantagens dos sais em relação aos óleos térmicos (HTF utilizado atualmente neste tipo de instalações), realizadas simulações em SAM para analisar a performance de uma plataforma com os distintos fluidos e por fim determinadas as alterações provocadas no LCOE assim como no desempenho e eficiência do bloco de potência.
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Simpson, Zachary Ian. "Advanced Materials for Energy Conversion and Storage: Low-Temperature, Solid-State Conversion Reactions of Cuprous Sulfide and the Stabilization and Application of Titanium Disilicide as a Lithium-Ion Battery Anode Material." Thesis, Boston College, 2013. http://hdl.handle.net/2345/3042.
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Thesis advisor: Dunwei WangIn this work, we present our findings regarding the low-temperature, solid-state conversion of Cu₂S nanowires to Cu₂S/Cu₅FeS₄ rod-in-tube structures, Cu₂S/ZnS segmented nanowires, and a full conversion of Cu₂S nanowires to ZnS nanowires. These conversion reactions occur at temperatures as low as 105 degrees Celsius, a much lower temperature than those required for reported solid-state reactions. The key feature of the Cu₂S nanowires that enables such low conversion temperatures is the high ionic diffusivity of the Cu⁺ within a stable S sublattice. The second portion of this work will focus on the oxide-stabilization and utilization of TiSi₂ nanonets as a lithium-ion battery anode. This nanostructure, first synthesized in our lab, was previously demonstrated to possess a lithium storage capacity when cycled against a metallic Li electrode. However, with subsequent lithiation and delithiation cycles, the TiSi₂ nanonet structure was found to be unstable. By allowing a thin oxide layer to form on the surface of the nanonet, we were able to improve the capacity retention of the nanonets in a lithium-ion half-cell; 89.8% of the capacity of the oxide-coated TiSi₂ was retained after 300 cycles compared to 62.3% of the capacity of as-synthesized TiSi₂ nanonets after 300 cycles. The layered structure of C49 TiSi₂ exhibited in the nanonets allows for a specific capacity greater than 700 mAh g(-1), and the high electrical conductivity of the material in conjunction with the layered structure confer the ability to cycle the anode at rates of up to 6C, i.e., 10 minute charge and discharge cycles, while still maintaining more than 75% of the capacity at 1C, i.e., 1 hour charge and discharge cycles
Thesis (MS) — Boston College, 2013
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Silva, Robson José da [UNESP]. "Efeito da temperatura e de hospedeiros no desenvolvimento de Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae, Aphidiinae)." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/102310.
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O parasitoide Diaeretiella rapae (McIntosh) é considerado um importante inimigo natural de pulgões em culturas de brassicáceas, apresentando potencial como agente de controle biológico desses insetos-praga. O presente estudo visou obter informações sobre D. rapae para subsidiar o desenvolvimento de programas de controle biológico de pulgões em cultivos de brassicáceas. Foram considerados os seguintes objetivos específicos: a) avaliar a qualidade hospedeira de Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach) e Brevicoryne brassicae (L.); b) determinar as exigências térmicas; c) determinar as tabelas de vida de fertilidade em diferentes temperaturas e d) avaliar o efeito do armazenamento à baixa temperatura. Para condução dos experimentos e criação das espécies de pulgões e parasitoide utilizaram-se plantas de couve-manteiga (Brassica oleracea var. acephala) Da Geórgia. A qualidade hospedeira foi investigada utilizando-se câmara climatizada regulada a 25 ± 1ºC, 60 ± 10% UR e 12 horas de fotofase e considerando-se as seguintes variáveis biológicas de D. rapae: parasitismo, períodos de desenvolvimento, porcentagem de emergência de adultos, razão sexual, longevidade e tamanho. As exigências térmicas e tabelas de vida de fertilidade foram determinadas em câmaras climatizadas reguladas a 15, 20, 25 e 30 ± 1 ºC, 60 ± 10% UR e 12 horas de fotofase. Para o armazenamento à baixa temperatura utilizou-se câmara climatizada sob temperatura constante de 5 ± 1°C nos seguintes períodos: 0, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 30, 32, 34 e 36 dias. Entre as espécies de pulgões estudadas M. persicae foi a que proporcionou maior qualidade a D. rapae. O limite térmico inferior de desenvolvimento (Tb) e a constante térmica (K) do parasitoide foram 4,0°C e 245,3 GD, respectivamente. A temperatura afetou o desempenho reprodutivo de D. rapae, sendo 25°C...
The parasitoid Diaeretiella rapae (McIntosh) is considered an important natural enemy of aphids in Brassicaceae, showing potential as a biological control agent of insect pests. This study aimed at obtaining information about D. rapae to subsidize the development of programs for biological control of aphids in Brassicaceae. Were considered the following specific objectives: a) to assess the host quality Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach) and Brevicoryne brassicae (L.), b) to determine the thermal requirements, c) to determine the fertility life tables at different temperatures and d) to evaluate the effect of storage at low temperature. The experiments and rearing of parasitoid and aphid species were conducted using cabbage plants (Brassica oleracea var. acephala) Da Geórgia. The host quality was investigated using climate chamber at 25 ± 1 º C, 60 ± 10% RH and 12 h photophase and considering the following biological variables of D. rapae: parasitism, developmental periods, percentage of adult emergence, sex ratio, longevity and size. The thermal requirements and fertility life tables were determined in climatic chambers at 15, 20, 25 and 30 ± 1 º C, 60 ± 10% RH and 12 hours photophase. The storage at low temperature was determined under constant temperature of 5 ± 1 ° C in the following periods: 0, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 30, 32, 34 and 36 days. Among the aphid species studied M. persicae showed high quality to D. rapae. The lower thermal threshold (Tb) and thermal constant (K) of the parasitoid were 4.0 °C and 245.3 GD, respectively. The temperature affected the reproductive performance of D. rapae, 25 ° C provided the best thermal conditions for the population growth of the specie. The storage of D. rapae at 5 °C for up to 32 days does not negatively affect the emergence and survival. The storage up to 36 days did not influence... (Complete abstract click electronic access below)
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Mayer, Didier. "Etude des proprietes thermophysiques de materiaux a transition solide-solide en vue d'applications au stockage de la chaleur." Paris, ENMP, 1987. http://www.theses.fr/1987ENMP0063.
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La determination de ces proprietes de cristaux plastiques de la famille des polyols a debouche sur la selection de trois composes organiques : le pentaerythritol, le pentaglycerine et le neopentylglycol, a partir desquels des melanges de solutions solides stables sont possibles. Le niveau de temperature peut etre choisi dans une gamme allant de 25**(o)c a 95**(o)c et de 165**(o)c a 185**(o)c; les enthalpies de transition sont comprises entre 80 kj/kg et 250 kj/kg. Mise en oeuvre avec incorporation de 80% de resines synthetiques en masse. Resultats
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Silva, Robson José da. "Efeito da temperatura e de hospedeiros no desenvolvimento de Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae, Aphidiinae) /." Jaboticabal : [s.n.], 2011. http://hdl.handle.net/11449/102310.
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Orientador: Francisco Jorge CividanesBanca: Sergio Antonio De Bortoli
Banca: Nelson Wanderley Perioto
Banca: José Roberto Postali Parra
Banca: Marcus Vinicius Sampaio
Resumo: O parasitoide Diaeretiella rapae (McIntosh) é considerado um importante inimigo natural de pulgões em culturas de brassicáceas, apresentando potencial como agente de controle biológico desses insetos-praga. O presente estudo visou obter informações sobre D. rapae para subsidiar o desenvolvimento de programas de controle biológico de pulgões em cultivos de brassicáceas. Foram considerados os seguintes objetivos específicos: a) avaliar a qualidade hospedeira de Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach) e Brevicoryne brassicae (L.); b) determinar as exigências térmicas; c) determinar as tabelas de vida de fertilidade em diferentes temperaturas e d) avaliar o efeito do armazenamento à baixa temperatura. Para condução dos experimentos e criação das espécies de pulgões e parasitoide utilizaram-se plantas de couve-manteiga (Brassica oleracea var. acephala) Da Geórgia. A qualidade hospedeira foi investigada utilizando-se câmara climatizada regulada a 25 ± 1ºC, 60 ± 10% UR e 12 horas de fotofase e considerando-se as seguintes variáveis biológicas de D. rapae: parasitismo, períodos de desenvolvimento, porcentagem de emergência de adultos, razão sexual, longevidade e tamanho. As exigências térmicas e tabelas de vida de fertilidade foram determinadas em câmaras climatizadas reguladas a 15, 20, 25 e 30 ± 1 ºC, 60 ± 10% UR e 12 horas de fotofase. Para o armazenamento à baixa temperatura utilizou-se câmara climatizada sob temperatura constante de 5 ± 1°C nos seguintes períodos: 0, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 30, 32, 34 e 36 dias. Entre as espécies de pulgões estudadas M. persicae foi a que proporcionou maior qualidade a D. rapae. O limite térmico inferior de desenvolvimento (Tb) e a constante térmica (K) do parasitoide foram 4,0°C e 245,3 GD, respectivamente. A temperatura afetou o desempenho reprodutivo de D. rapae, sendo 25°C... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The parasitoid Diaeretiella rapae (McIntosh) is considered an important natural enemy of aphids in Brassicaceae, showing potential as a biological control agent of insect pests. This study aimed at obtaining information about D. rapae to subsidize the development of programs for biological control of aphids in Brassicaceae. Were considered the following specific objectives: a) to assess the host quality Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach) and Brevicoryne brassicae (L.), b) to determine the thermal requirements, c) to determine the fertility life tables at different temperatures and d) to evaluate the effect of storage at low temperature. The experiments and rearing of parasitoid and aphid species were conducted using cabbage plants (Brassica oleracea var. acephala) Da Geórgia. The host quality was investigated using climate chamber at 25 ± 1 º C, 60 ± 10% RH and 12 h photophase and considering the following biological variables of D. rapae: parasitism, developmental periods, percentage of adult emergence, sex ratio, longevity and size. The thermal requirements and fertility life tables were determined in climatic chambers at 15, 20, 25 and 30 ± 1 º C, 60 ± 10% RH and 12 hours photophase. The storage at low temperature was determined under constant temperature of 5 ± 1 ° C in the following periods: 0, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 30, 32, 34 and 36 days. Among the aphid species studied M. persicae showed high quality to D. rapae. The lower thermal threshold (Tb) and thermal constant (K) of the parasitoid were 4.0 °C and 245.3 GD, respectively. The temperature affected the reproductive performance of D. rapae, 25 ° C provided the best thermal conditions for the population growth of the specie. The storage of D. rapae at 5 °C for up to 32 days does not negatively affect the emergence and survival. The storage up to 36 days did not influence... (Complete abstract click electronic access below)
Doutor
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Nešpor, Pavel. "Návrh vytápění pro nízkoenergetický rodinný dům." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229227.
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My diploma thesis is focused on design scheme of low-energy family house’s heating system. The goal of the first part of thesis is an introduction of the object following by calculations of transmission coefficients of heat through constructions and calculations of heat loss. Creation of proposal and calculation of underfloor heating output as well as panel and piped radiators and convectors are followed by proposal and calculation of dimensions of piping, pressure loss of underfloor loops, panel and piped radiators and convectors. The thesis also contains design of heating pump with bivalent heat electrical source, calculations of need of heat and calculations of total costs of working heating system as well as design of storage tank and accumulator for hot water. The last part of thesis is focused on control of the heat system.
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Gondre, Damien. "Numerical modeling and analysis of heat and mass transfers in an adsorption heat storage tank : Influences of material properties, operating conditions and system design on storage performances." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI022/document.
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Le développement de solutions de stockage de l'énergie est un défi majeur pour permettre la transition énergétique d'un mix énergétique fortement carboné vers une part plus importante des énergies renouvelables. La nécessité de stocker de l'énergie vient de la dissociation, spatiale et temporelle, entre la source et la demande d'énergie. Stocker de l'énergie répond à deux besoins principaux : disposer d'énergie à l'endroit et au moment où on en a besoin. La consommation de chaleur à basse température (pour le chauffage des logements et des bureaux) représente une part importante de la consommation totale d'énergie (environ 35 % en France en 2010). Le développement de solutions de stockage de chaleur est donc d'une grande importance, d'autant plus avec la montée en puissance des énergies renouvelables. Parmi les technologies de stockage envisageables, le stockage par adsorption semble être le meilleur compromis en termes de densité de stockage et de maintient des performances sur plusieurs cycles de charge-décharge. Cette thèse se focalise donc sur le stockage de chaleur par adsorption, et traite de l'amélioration des performances du stockage et de l'intégration du système au bâtiment. L'approche développée pour répondre à ces questions est numérique. L'influence des propriétés thermophysiques de l'adsorbant et du fluide sur la densité de puissance d'une part, mais aussi sur la densité de stockage et l'autonomie du système, est étudiée. L'analyse des résultats permet de sélectionner les propriétés des matériaux les plus influentes et de mieux comprendre les transferts de chaleur et de masse au sein du réacteur. L'influence des conditions opératoires est aussi mise en avant. Enfin, il est montré que la capacité de stockage est linéairement dépendante du volume de matériau, tandis que la puissance dépend de la surface de section et que l'autonomie dépend de la longueur du lit d'adsorbant. Par ailleurs, le rapport entre l'énergie absorbée (charge) et relâchée (décharge) est d'environ 70 %. Mais pendant la phase de charge, environ 60 % de la chaleur entrant dans le réacteur n'est pas absorbée et est directement relâchée à la sortie. La conversion globale entre l'énergie récupérable et l'énergie fournie n'est donc que de 25 %. Cela montre qu'un système de stockage de chaleur par adsorption ne peut pas être pensé comme un système autonome mais doit être intégré aux autres systèmes de chauffage du bâtiment et aux lois de commande qui les régissent. Utiliser la ressource solaire pour le préchauffage du réacteur est une idée intéressante car elle améliore l’efficacité de la charge et permet une réutilisation de la part récupérée en sortie pour le chauffage direct du bâtiment. La part stockée sous forme sensible peut être récupérée plusieurs heures plus tard. Le système est ainsi transformé en un stockage combiné sensible/adsorption, avec une solution pour du stockage à long terme et pour du stockage à court termeThe development of energy storage solutions is a key challenge to enable the energy transition from fossil resources to renewable energies. The need to store energy actually comes from a dissociation between energy sources and energy demand. Storing energy meets two principal expectations: have energy available where and when it is required. Low temperature heat, for dwellings and offices heating, represents a high share of overall energy consumption (i.e. about 35 %). The development of heat storage solutions is then of great importance for energy management, especially in the context of the growing part of renewable energies. Adsorption heat storage appears to be the best trade off among available storage technologies in terms of heat storage density and performances over several cycles. Then, this PhD thesis focuses on adsorption heat storage and addresses the enhancement of storage performances and system integration. The approach developed to address these issues is numerical. Then, a model of an adsorption heat storage tank is developed, and validated using experimental data. The influence of material thermophysical properties on output power but also on storage density and system autonomy is investigated. This analysis enables a selection of particularly influencing material properties and a better understanding of heat and mass transfers. The influence of operating conditions is also underlined. It shows the importance of inlet humidity on both storage capacity and outlet power and the great influence of discharge flowrate on outlet power. Finally, it is shown heat storage capacity depends on the storage tank volume, while outlet power depends on cross section area and system autonomy on bed length. Besides, the conversion efficiency from absorbed energy (charge) to released energy (discharge) is 70 %. But during the charging process, about 60 % of incoming heat is not absorbed by the material and directly released. The overall conversion efficiency from energy provided to energy released is as low as 25 %. This demonstrates that an adsorption heat storage system cannot be thought of as a self-standing component but must be integrated into the building systems and control strategy. A clever use of heat losses for heating applications (in winter) or inlet fluid preheating (in summer) enhances global performances. Using available solar heat for system preheating is an interesting option since a part is instantly retrieved at the outlet of the storage tank and can be used for direct heating. Another part is stored as sensible heat and can be retrieved a few hours later. At least, it has the advantage of turning the adsorption storage tank into a combined sensible-adsorption storage tank that offers short-term and long-term storage solutions. Then, it may differ avoidable discharges of the sorption potential and increase the overall autonomy (or coverage fraction), in addition to optimizing chances of partial system recharge
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Mutinda, Samuel I. "Hydrothermal Synthesis of Shape/Size-Controlled Cerium-Based Oxides." Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1378917332.
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Oliveira, João Alison Alves. "Tolerância ao frio dos frutos de diferentes cultivares de bananeiras." Universidade Federal de Viçosa, 2014. http://locus.ufv.br/handle/123456789/4638.
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Previous issue date: 2014-07-25Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The objective of this study was to evaluate the tolerance of fruits of different banana cultivars to low temperature storage. Fruits of the cultivars Nanicão (AAA), Prata (AAB), Vitória (AAAB), Maçã (AAB) and Caipira (AAA) were used. Hands were subdivided into clusters of three fruits, which were kept in cold storage for 7, 14 and 21 days, with an average temperature of 10.53 0.37 °C and relative humidity of 85%. Subsequently, the clusters were transferred to the temperature of 22 0.39 °C, to complete the ripening. The experiment was in a split plot design, having five cultivars in the plots and evaluation days in the subplots, in a completely randomized design with four replications and one cluster per experimental unit. Data were analyzed by variance analyses and regression. The Dunnett test at 5% probability was used to compare data from control (start of storage) with those of the end of storage. Each storage period was analyzed separately. The fruits of all cultivars remained green after 21 days of storage at 10.53 C 0.37 °C. Fruits of the cultivar Nanicão did not complete the ripening after they were transferred to 22 °C, when stored for 7 days at low temperature. These fruits were firmer, with green skin, low soluble solids and low titratable acidity. After 21 days of cold storage, the fruits of all cultivars completed ripening, when transferred to room temperature. The chilling injury increased with the advance of the cold storage for all cultivars. Fruits of Nanicão , Caipira and Maçã had more obvious symptoms of chilling injury. Fruits of Prata and Vitória were more tolerant to cold storage at a temperature of 10.53 °C for up to 21 days, showing normal ripening after transfer to 22 °C.
O objetivo deste trabalho foi avaliar a tolerância dos frutos de diferentes cultivares de bananeira a baixa temperatura de armazenamento. Foram utilizados frutos dos cultivares Nanicão (AAA), Prata (AAB), Vitória (AAAB), Maçã (AAB) e Caipira (AAA). Utilizaram-se buquês com três frutos, mantidos em câmara fria por 7, 14 e 21 dias, com temperatura média de 10,53 0,37 °C e umidade relativa do ar de 85%. Posteriormente, os buquês foram transferidos para a temperatura de 22 0,39 °C, para completar o amadurecimento. O experimento foi em esquema de parcelas subdivididas, tendo-se nas parcelas cinco cultivares e nas subparcelas os dias de avaliação, no delineamento inteiramente casualizado, com quatro repetições e um buquê de três frutos por unidade amostral. Os dados foram analisados por meio de análises de variância e regressão. O teste de Dunnett foi utilizado para comparar os dados da testemunha (início do armazenamento) com os dos dias do fim do armazenamento, a 5% de probabilidade. Cada período de armazenamento foi analisado separadamente. Os frutos dos cultivares estudados permaneceram verdes após 21 dias de armazenamento à 10,53 0,37 °C. Frutos do cultivar Nanicão não completaram o amadurecimento após serem transferidos para a temperatura de 22 °C, quando armazenados por 7 dias à baixa temperatura, apresentando frutos mais firmes, com casca verde, baixos teores de sólidos solúveis e acidez titulável. Após 21 dias de armazenamento refrigerado, os frutos de todos os cultivares completaram o amadurecimento, depois de transferidos para temperatura ambiente. Os danos por frio aumentaram com o avanço do tempo de armazenamento refrigerado, para todos os cultivares. Nanicão , Caipira e Maçã apresentaram sintomas mais evidentes de dano por frio. As bananas Prata e Vitória mostraram-se mais tolerantes ao armazenamento refrigerado na temperatura de 10,53 °C por até 21 dias, exibindo amadurecimento normal após a transferência para a temperatura de 22 °C.
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Kytýrová, Zdeňka. "Návrh otopného systému pro nízkoenergetický rodinný dům." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228144.
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This diploma thesis deals with the design of a heating system for a "low-energy" house. It is conceived as a low temperature system using a combination of radiators and underfloor heating. The design is supplemented with a calculation of heat loss, a proposal of needed components, a scheme of the system and means of regulation. The second part solves the heat source selection. A solar system with vacuum tubes is used as the primary source. The second one is an electrical water heater located in the accumulation reservoir for the hot domestic water. Necessary calculations for the design of the solar system, together with a scheme and means of regulation, are enclosed in this section.
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Pibaleau, Baptiste. "Elaboration et caractérisation d'électrodes VACNT/MnO2 pour application aux supercondensateurs hybrides." Thesis, Tours, 2018. http://www.theses.fr/2018TOUR4034/document.
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Les travaux de cette thèse ont porté sur l'élaboration, l'optimisation et l'étude d'électrodes composites de nanotubes de carbone verticalement alignés (VACNT) sur un collecteur d'aluminium et modifiés par l'oxyde de manganèse (MnO₂). Les VACNT synthétisés par voir CVD à basse température (580°C:) directement sur le collecteur ont permis d'obtenir des tapis de NTC parfaitement alignés d'une épaisseur allant de 20 à 80 µm et possédant des densités de 10¹¹ NTC.cm² et dont le taux de catalyseur (Fe) est inférieur à 1%. Leur modification par du MnO2 permet d’accroître leur capacité de stockage électrochimique. Afin de réaliser un enrobage optimal des VACNT par le MnO₂, différents précurseurs de l'oxyde ainsi que diverses méthodes(dépôts électrochimiques, chimiques, CVD) ont été utilisées et optimisées. Les composites élaborés ont ensuite été étudiées en tant que matériau d'électrode pour la réalisation de supercondensateurs asymétriques eu milieux aqueuxThis thesis was focused on the development, optimization and study of composite electrodes of vertically aligned carbon nanotubes (VACNT) on an aluminum collector and modified with manganese oxide (MnO₂).VACNT were synthesized by a CVD process at low temperature (580° C) directly on the collector. Perfectly aligned CNT forest with a thickness of 20 to 80 μm were obtained with high densities of 10¹¹ NTC.cm² and whose catalyst (Fe) content is less than 1%. Their modification with MnO₂ increase their electrochemical storage capacity. In order to achiew optimal coating of VACNT by MnO₂, different precursors of the oxide and various methods ( electrochemical, chemical, CVD) were used and optimized. Composites were studied as electrode material for the realization of asymmetric supercapacitors in aqueous media. In addition, structurals, morphologicals and electrochemicals analyzes carried out on the different materials allowed a better understanding of the role of the elaboration's conditions on the properties of the VACNT/MnO₂ composites obtained
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Hallqvist, Karl. "Högtempererat borrhålslager för fjärrvärme." Thesis, Uppsala universitet, Naturresurser och hållbar utveckling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-231586.
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The district heating load is seasonally dependent, with a low load during periods of high ambient temperature. Thermal energy storage (TES) has the potential to shift heating loads from winter to summer, thus reducing cost and environmental impact of District Heat production. In this study, a concept of high temperature borehole thermal energy storage (HT-BTES) together with a pellet heating plant for temperature boost, is presented and evaluated by its technical limitations, its ability to supply heat, its function within the district heating system, as well as its environmental impact and economic viability in Gothenburg, Sweden, a city with access to high quantities of waste heat. The concept has proven potentially environmentally friendly and potentially profitable if its design is balanced to achieve a good enough supply temperature from the HT-BTES. The size of the heat storage, the distance between boreholes and low borehole thermal resistance are key parameters to achieve high temperature. Profitability increases if a location with lower temperature demand, as well as risk of future shortage of supply, can be met. Feasibility also increases if existing pellet heating plant and district heating connection can be used and if lower rate of return on investment can be accepted. Access to HT-BTES in the district heating network enables greater flexibility and availability of production of District Heating, thereby facilitating readjustments to different strategies and policies. However, concerns for the durability of feasible borehole heat exchangers (BHE) exist in high temperature application.Värmebehovet är starkt säsongsberoende, med låg last under perioder av högre omgivningstemperatur och hög last under perioder av lägre omgivningstemperaturer. I Göteborg finns en stor mängd spillvärme tillgängligt för fjärrvärmeproduktion sommartid när behovet av värme är lågt. Tillgång till säsongsvärmelager möjliggör att fjärrvärmeproduktion flyttas från vinterhalvår till sommarhalvår, vilket kan ge såväl lönsamhet som miljönytta. Borrhålsvärmelager är ett förhållandevis billigt sätt att lagra värme, och innebär att berggrunden värms upp under sommaren genom att varmt vatten flödar i borrhål, för att under vinterhalvåret användas genom att låta kallt vatten flöda i borrhålen och värmas upp. I traditionella borrhålsvärmelager används ofta värmepump för att höja värmelagrets urladdade temperatur, men på grund av höga temperaturkrav för fjärrvärme kan kostnaden för värmepump bli hög. I denna rapport föreslås ett system för att klara av att nå höga temperaturer till en lägre kostnad. Systemet består av ett borrhålsvärmelager anpassat för högre temperaturer (HT-BTES) samt pelletspannor för att spetsa lagrets utgående fluid för att nå hög temperatur. Syftet med rapporten är att undersöka potentialen för detta HT-BTES-system med avseende på dess tekniska begränsningar, förmåga till fjärrvärmeleverans, konsekvenser för fjärrvärmesystemet, samt lönsamhet och miljöpåverkan. För att garantera att inlagringen av värme inte är så stor att priset för inlagrad värme ökar väsentligt, utgår inlagringen från hur mycket värme som kyls bort i fjärrvärmenätet sommartid. I verkligheten finns betydligt mer värme tillgänglig till låg kostnad. När HT-BTES-systemet producerar fjärrvärme, ersätts fjärrvärmeproduktion från andra produktionsenheter, förutsatt att HT-BTES-systemets rörliga kostnader är lägre. I Göteborg ersätts främst naturgas från kraftvärme, men också en del flis. Kostnadsbesparingen beror på differensen för total fjärrvärmeproduktionskostnad med och utan HT-BTES-systemet. Undersökningen visar att besparingen är större om HT-BTES-systemet placeras i ett område där det är möjligt att mata ut fjärrvärme med lägre temperatur. Om urladdning från HT-BTES kan ske med hög temperatur ökar också besparingen. Detta sker om lagrets volym ökar, om avståndet mellan borrhål minskar eller om värmeöverföringen mellan det flödande vattnet i borrhålen och berggrunden ökar. Dessa egenskaper för lagret leder också till minskade koldioxidutsläpp. Storleken på besparingen beror dock i hög grad på hur bränslepriser utvecklas i framtiden. Strategiska fördelar med HT-BTES-systemet inkluderar; minskad miljöpåverkan, robust system med lång teknisk livslängd (för delar av HT-BTES-systemet), samt att inlagring av värme kan ske från många olika produktionsenheter. Dessutom kan positiva bieffekter identifieras. Undersökningen visar att HT-BTES-systemet har god potential att ge lönsamhet och minskad miljöpåverkan, och att anläggning och drift av lagret kan ske utan omfattande lokal miljöpåverkan. Det har också visats att de geologiska förutsättningarna för HT-BTES är goda på många platser i Göteborg, även om lokala förhållanden kan skilja sig åt. För att nå lönsamhet för HT-BTES-systemet krävs en avvägning på utformning av lagret för att nå hög urladdad temperatur utan att investeringskostnaden blir för stor. Undersökningen visar att om anslutning av HT-BTES-systemet kan ske mot befintlig anslutningspunkt eller till befintlig värmepanna kan investeringskostnaden minska och därmed lönsamheten öka. Placering av HT-BTES-systemet i områden med risk för överföringsbegränsningar kan också minska behovet av att förstärka fjärrvärmenätet, och således bidra till att minska de kostnader som förstärkning av nätet innebär. Betydelsefulla parametrar för att nå lönsamhet för HT-BTES-system inkluderar dessutom kostnaden för inlagrad värme liksom vilket vinstkrav som kan accepteras. Tillgång till HT-BTES möjliggör ökad nyttjandegrad och flexibilitet för fjärrvärmeproduktionsenheter, och därmed ökad anpassningsmöjlighet till förändrade förutsättningar på värmemarknaden. Dock återstår att visa att komponenter som klarar de höga temperaturkraven kan tillverkas till acceptabel kostnad.
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Huang, Fu-hsiang, and 黃福祥. "Study on the postharvest low temperature storage of atemoya its Study on the postharvest low temperature storage of atemoya its export feasibility." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/88729625086450436478.
Full textAbstract:
碩士國立屏東科技大學
熱帶農業暨國際合作研究所
93
The total acreage of custard apple planted in Taitung was about 4500 ha; of which, two third of the acreage were sugar apple and the remaining one third was atemoya. Sugar apple has been known to be ripening easily after harvest, rendering it to be intolerable to low temperature storage. As a result, export of sugar apple was difficult. Atemoya, however, was better tolerable to low temperature storage. Previous studies showed that atemoya was ripening well after being stored at a temperature above 15oC; thus, had a longer shelf life. It was bruised easily when it was subjected to chilling below 10 oC and was unable to ripen properly. In addition, the air freight costs for shipping atemoya to foreign markets were expensive, costing about US$2/kg, as comparing to shipping by surface freight at US$0.16/kg. Therefore, atemoya shipped by surface freight under low temperature storage was the only option in order to minimize shipping costs, increase growers’ profits and preserve the freshness of atemoya before reaching its export markets. The objective of this study was to determine the optimal low temperature for storing atemoya to ensure its freshness and increase its shelf life to meet the competition in its export markets. Results of the study showed that after being stored at 5, 7, and 10oC for 10 or 15 days, the color and appearance of atemoya went through a series of changes. Storing for 10 or 15 days at 5 oC, significant changes were observed on atemoya in coloration and appearance as its skin turned brown to black and flesh was bruised by chilling effects. At 7 oC, however, there were no significant differences in the coloration and appearance of atemoya after it had been stored for 10 or 15 days. Also there was no significant difference in the flesh of atemoya as no chilling injury was observed and fruits went through normal ripening process. The results further showed that 7 oC was the optimal temperature for storing atemoya in the process of transportation to its export markets. Temperature was the most critical factor in affecting the storage duration and quality of atemoya. Low temperature decreased the physiological activity in the ripening process; therefore, if appropriate measures could be taken to maintain the freshness during the storage of atemoya or other fruits, the post harvest ripening could be effectively delayed and their shelf life prolonged. Key words: atemoya, custard apple, chilling injury, optimal temperature, shelf life
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Leary, Lewis W. "Damping degradation in incramute and sonoston due to low temperature storage." Thesis, 1986. http://hdl.handle.net/10945/21754.
Full text
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蘇新智. "Energy saving of ice storage in low temperature water district cooling application." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/92899439570243514593.
Full textAbstract:
碩士國立臺北科技大學
電機工程系碩士班
89
Cool storage central air-conditioning system uses off-peak power to produce ice or cool storage, and then uses the cool energy for cooling during the summer peak period. Therefore, it reduces the peak power load and makes full use of off peak power. Besides, the low temperature characteristics of cool storage can be used in district cooling. The low temperature chilled water produced by the cool storage can be used to increase the temperature difference of the chilled water one fold, so to reduce the water flow rate by half and save the cost of the transport of water. This breakthrough can further enhance the advantages of district cooling, and help to promote its applications. It will also help Taipower to alleviate the problem of insufficient power supply in urban areas. Besides, it will help to level the power demand between the peak and off-peak periods. This report explains the characteristics of different cool storage designs. Their feasibilities in district cooling application are discussed. Some successful applications in other countries are reported and analyzed. The technologies that lead to the advantages are explained. Low temperature chilled water systems are analyzed in terms of its designs. The benefits of low temperature chilled water system are also discussed. This research also analyses the system heat loss and pump power consumption. For piping loss, an assumed example is used in the analysis. Energy consumption characteristics of commercial pumps are used in the analysis. The results show that to transport 7℃cooling water in a 3 km pipe will result in pump power load about 16.6% of the cool energy delivered. If the water temperature is lowered to reduce the flow rate, the pump power load can be decreased to 4.64﹪. This research also analyzes the heat loss of piping and ice tanks by calculation and numerical analysis. The results show that the heat gain of each meter pipe is about 10W/m. For a fully charged ice tank in a proper indoor environment, the ice residue ratio can still be 92.52﹪after a week. The results of this research help to lay more foundation in the design of cool storage district cooling. This research also contributes to the evaluation of heat and flow loss of cool storage systems.
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Chang, Cheng-Rung, and 張晟榮. "The Storage Location of Decision Support System for Logistics Center of low-temperature." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/05651539014429226410.
Full textAbstract:
碩士元智大學
企業管理學系
93
According to development of internal economic and increasing of national income, the demand of consumption and sense of consumer rises progressively. The business model of traditional retail business also follows this trend to innovate and change continuously and affects the whole system of marketing channel. Logistics is defined that the related operation of goods transportation, stock management, order executing and materiel handling etc.. The Warehouse management system（WMS）is the most important part for information system. A WMS designed fine can increase operation efficiency and quality of customer service. Besides reaching customer satisfaction and creating new operational moment, it is an important hinge in business model of supply chain because of it has a function which creates add-value. In the past, most of questions of rising operational efficiency in logistics center researched from order picking routing or storage location designing, but few of researches established and operated DSS. Therefore, this research is base on the warehouse data of logistics center of low temperature and uses PV-wave and J-wave to establish DSS of planning storage location. I hope that using DSS assists in managing storage location to save manpower and costs and to reinforce operation efficiency. Finally, the research provides database and model base of system for industry to establish or improve WMS.
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HUANG, TZUYU, and 黃子郁. "Effects of Low Temperature Storage on Growth and Flowering of Two Strawberry Cultivars." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/9925kn.
Full textAbstract:
碩士國立宜蘭大學
園藝學系碩士班
104
Growth and flowering performance of strawberry (Fragaria x ananassa Duch.) are influenced by photoperiod and temperature. The main objective of this study is to determine how flowering performance can be affected by low temperature and darkness. By extending the storage period under low temperature, the effect of supplemental light of different light quality was determined. In the first part of the study, strawberry cv. ‘Aroma' and ‘Toyonoka’ plants were placed in a 13°C dark chamber for 8 days (8D), 12 days (12D) or intermittent with 4 days in a phytotron, 4 days outdoor and 4 days in the phytotron before being planted in a six-inch pot respectively. Strawberry cv. ’Toyonoka’ plants were also treated with two different temperatures (5°C and 13°C) for 4 days (4D), 8 days (8D) and 4-day intermittent cycle (4I). The result shows that strawberry cv. ‘Toyonoka’ is significantly affected by low-temperature storage when the total treatment period is longer than 8 days, while higher flowering rates were observed for both the 5°C and 13°C treatments. Treatments under 5°C resulted in a higher value of total soluble solid and titratable acidity. For treatments stored under low temperature longer than 8 days, the flowering rate was significantly higher than CK and 4D at the end of the experiment. However, low-temperature storage does not show significant effect on strawberry cv. ‘Aroma’ .In the second part of the study, supplemental light with 6 different light qualities have been used in a 9°C phytotron. Many plants were potted after 2 weeks, 4 weeks and 8 weeks as three different treatments. The result shows that compared with darkness storage, loss of chlorophyll, soluble sugar and starch content can be reduced by applying 50 μmol supplemental lighting 12 hour/day. 80% of the plants treated with CW and RB could be found flowering 21days after 8 weeks treatment.
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Makama, Sandile Donald, and 馬山帝. "Effect of slow growth and ultra-low temperature on the storage of Kohleria synseed." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/02464941142650436966.
Full textAbstract:
碩士國立屏東科技大學
熱帶農業暨國際合作系
104
In vitro conservation of plant genetic resources is important for food security and agro-biodiversity. It has the potential to guarantee the long-term preservation of germplasm of species threatened with extinction. During the past years, in vitro techniques have been extensively developed and applied to more than 1,000 species, including many tropical species. In vitro conservation via slow growth technique has been considered a useful short-term storage system for the in vitro cultured plant materials, whereas cryopreservation has been used for the long-term preservation of plant germplasm. This study aims at establishing a short- and long-term conservation protocol for Kohleria using shoot tip-based synseed. Synseeds were produced when the shoot tips were encapsulated with 3% sodium alginate in combination with 100 mM calcium chloride. For the short-term storage, preservation techniques included the use of osmoticum (mannitol and sorbitol) at concentrations ranging from 2 to 16%, reduced temperature (4, 15 and 25°C) and reduced nutrient availability (full, ½ and ¼ Murashige and Skoog (MS) salts and vitamins). In the osmoticum experiment, best results were obtained with the 2% mannitol and 2% sorbitol combination treatment which resulted in a storability of 36.7% and a viability of 100% after the first month of storage. At temperature of 15°C synseeds maintained a high storability percentage of 100% throughout the 84 days period with a fairly good viability percentage after each month (68.5, 47.8 and 37.7%). Kohleria synseeds can be stored for up to 60 days at ¼ MS nutrient strength while still maintaining high viability percentage of 87.7 and 68.5% after the first and second month storage respectively. For the long-term storage the encapsulation-dehydration technique was used. Nine days preculture with 0.3 M sucrose followed by 6 hour dehydration resulted in a low moisture content of 23.6%. For encapsulation-vitrification, precultured synseeds were dehydrated for 0 to 6 hours and treated with PVS2 before rapid immersion in liquid nitrogen. Under these conditions, regrowth of explants was not successful. Despite several attempts in modifying the cryogenic conditions, no synseed survived the liquid nitrogen storage.
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Schwobe, Marlene A. "Effect of modified atmospheres and low temperature storage on carbohydrate metabolism in Solanum tuberosum." 1988. http://catalog.hathitrust.org/api/volumes/oclc/19034457.html.
Full textAbstract:
Thesis (M.S.)--University of Wisconsin--Madison, 1988.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 212-222).
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Dianawati, Dianawati. "Survival of encapsulated probiotic bacteria during storage at low water activity at ambient temperature." Thesis, 2014. https://vuir.vu.edu.au/25067/.
Full textAbstract:
Probiotics are defined by FAO/WHO (2001) as microorganisms that improve the
healthiness of the host when available in sufficient number in the human intestinal tract. Health
benefits of probiotic bacteria are correlated with the number of viable bacteria reaching the host
and the recommended bacterial population required is ≥107 CFU/g. Besides during processing
and storage, probiotic bacteria are required to survive during transit in gastrointestinal tract with
very low pH (1.8 – 2.0), in bile juice and pancreatin before beneficial effects are realized in the
lower small intestine and colon. Microencapsulation is effective in ensuring bacterial viability
which is influenced by the type of encapsulating materials, the methods used for encapsulation
and storage thereafter for a given bacterium. The use of microencapsulating materials is to entrap or immobilize probiotic bacteria
within microcapsule and to protect the bacteria during the drying process, which is the last stage
of microencapsulation. The objectives of this thesis were to study the effect of different types of
microencapsulants (alginate or casein-based formulations), and drying methods (freeze and spray
drying) on survival of probiotic bacteria for 10 weeks of storage at 25oC (ambient temperature)
at low water activities (aw). Three probiotic bacteria (Bifidobacterium animalis ssp. lactis Bb12,
Bifidobacterium longum and Lactobacillus acidophilus) and one strain of most sensitive lactic
acid bacteria (L. lactis ssp. cremoris) to acid and bile environment were encapsulated and
selected functional properties, such as survival, acid and bile tolerance, surface hydrophobicity,
and retaining of some of the enzyme activities were investigated. The protective mechanism of
microencapsulation was studied by determinations of microstructures using Environment
Scanning Electron Microscopy (ESEM), interactions with cellular components by Fourier Transform Infrared Spectroscopy (FTIR), and glass transition temperature (Tg) measurements by
Differential Scanning Calorimetry (DSC).
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Chen, Zih-Ting, and 陳子婷. "Effects of Photoperiod, Low Temperature Storage and Gibberellic Acids on Growth and Flowering ofLavandula spp." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/71879683557474808142.
Full textAbstract:
碩士臺灣大學
園藝學研究所
95
The objectives of this study were to discuss the effects of night interruption (NI), low temperature storage, and gibberellic acids (GAs) on growth and flowering of Lavandula andustifolia, L. heterophylla, and L. dentata, then to evaluate the potential of controlling the flowering period. A NI provided by tungsten lamps was treated to lavenders at 22:00 to 02:00. After NI, plant heights, the number of inflorescences, and lengths of inflorescences of L. andustifolia ‘Munstead’ were increased, and the number of nodes counted at flowering and days to flowering were reduced. Although plant heights and lengths of inflorescences were not promoted in Exp. 2, the number of inflorescences was greatly increased. The NI also increased plant heights and length of inflorescences and advanced the flowering date of L. heterophylla, but it was feckless to L. dentata. There were differences in responses to NI among the species under the genus Lavandula. Lavender cuttings were stored in 5℃ under dark condition for 0-8 weeks separately. After storage, cuttings were planted for 4 weeks to observe the effects of cold storage on growth. As the duration of low temperature storage increased, the content of soluble sugar and starch on three species of lavenders decreased. As the result of different storage-tolerance, the surviving rate, the root emergence rate, and cutting dry weight were decreased in different degree. However, L. heterophylla and L. dentata still had higher percentage of surviving cuttings and surviving percentage after planting after 8 weeks and 6 weeks storage, respectively. It means that this method could be applied to regulating the commercial production. Although low temperature was found to be able to promote the flowering of lavenders, appropriate storage condition is necessary to maintain the capability of growth and the nutrient of cuttings. Thus, the effects of low temperature storage on the flowering of lavender cuttings can be further discussed. Gibberellic acids are an intrinsic plant growth regulator that generally exists in plants. It can partially replace the role of vernalization and cold requirement of some biennials and perennials in non-inductive condition. To discuss the effects of GAs on growth and flowering of lavender, different concentration of GAs and GAs synthetic inhibitors was applied with the combination of different temperatures when applying GAs in this experiment. Results of the experiment showed that plant heights of L. angustifolia ‘Munstead’ and L. heterophylla were promoted by applying GA3, and plant heights of L. angustifolia ‘Munstead’ were significantly inhibited by applying GAs synthetic inhibitor. Applying low concentration of GA3 on the flower buds of L. angustifolia ‘Munstead’ and L. heterophylla didn’t facilitate flowering. However, days to flowering of L. angustifolia ‘Munstead’ were increased and lengths of inflorescences were reduced by spraying PP333. It indicates the importance of GAs in the flowering process of lavenders. Lavendula heterophylla showed more vigor while being grown under relatively high temperature (30/25℃、25/20℃) but never flowered till the end of the experiment. The relative low temperature condition (20/15℃、15/12℃) was beneficial to flower initiation of lavenders. When being applied under the temperature lower than the ideal condition, GAs advanced the time of visible bud appearance and flowering, and increased the lengths of inflorescences. The result showed that GAs was incapable of promoting flower initiation, but it could induce the flower development in some specific condition. Among the various GAs, GA3 had better or similar influence of promoting growth and flower development than GA4+7 on L. heterophylla. GAs could promote the flowering of L. heterophylla in some specific circumstances. Further researches are necessary to determine the most effective concentration and timing of GAs usage to lavenders, and to evaluate the potential of controlling the flowering period.
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Lu, Chiu-Tung, and 盧秋通. "The effect of low temperature storage on some biological chacteristics of Mallada basalis〈Neuroptera: Chrysopidae〉." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/77626108706550734943.
Full textAbstract:
碩士國立中興大學
昆蟲學系
92
The lacewing (Mallada basalis (Walker)) is a native species in Taiwan. It is an important natural enemy which preyed on small insect pests such as aphids, scale insects and whiteflies. In the laboratory, the eggs, pupae and adults were tested in various low temperature storages. Eggs were stored at 8 constant temperatures, and the results showed that no hatching were found at 4, 8, and 32℃, while the hatching rate at 12, 16, 20, 24 and 28℃ were 43.3, 82.5, 87.5, 86.7 and 91.7％, respectively. The results showed that when 1-day-old eggs of M. basalis were stored at 4, 8, 12 and 16℃ for seven days and then transfered to 28℃, the results showed that the hatching rate were 11.7, 17.5, 79.2 and 78.3％, respectively. The survival rate of 1st, 2nd and 3rd instar larvae stored at 12℃ were 98.1, 92.3 and 82.7％, as well as stored at 16℃ were 96.7, 95.0 and 95.0％. Emergence rate at 12℃ and 16℃ were 42.1 and 69.5％, respectively. The egg productions at 16℃ was 416.1 eggs/female higher than the other treatments. The hatching rate of the female showed the 65.0％ at 12℃ treatment and 66.7％ at 16℃ treatment. The pupae at four treatments showed 0, 25.0, 69.0 and 77.1％ emergence rate at 10 days storage and 0, 32.0, 53.1 and 68.8％ at 15 days storage. Egg production stored at 12 and 16℃ for 10 days showed 421.7 and 414.4 eggs/female which was not significantly different compared with the control. Egg production of storage for 15 days showed 397.0 and 368.1 eggs/female. Pupal duration were affected by the cold treatment. The higher temperature effected the lower pupal development under 12 and 16℃ the pupal duration showed the lower and increased the emergence rate. Adult survival rates stored at 5℃ for 2 wks with three different photoperiod treatment (L：D＝14：10; 10：14; 8：16) maintained 83.3％ and for 4wks decreased to 28.1％. Adult survival rates stored at 10℃for 8 wks showed the 70.9∼81.3％ between the three photoperiod treatments. The adult survival rates were decreased along with the storage durations. The egg production of adult females which were stored at 10℃ and three different photoperiods for 8 wks were 487.3, 344.9 and 377.0 eggs/female, respectively. It was not significantly different compared with the control. The results of egg production of adult females which were stored at 10℃ for 14 wks were decreased significantly. When 1-day-old eggs of M. basalis stored at 4、8、12 and 16℃ for seven days, and their 3rd instar larvae daily consumed weight were 2.4, 2.3, 7.9 and 7.1 mg. There were not significantly different among the 12, 16 and 28℃（control）. Key words: Chrysopidae, Mallada, low temperature storage, survival rate, photoperiod
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Huang, Yu-Tzu, and 黃祐慈. "Effects of Ethylene Degreening, Low-temperature Quarantine Treatment, and Storage Temperature on Coloration of ‘Ponkan’ Mandarin (Citrus reticulata Blanco cv. ‘Ponkan’)." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/80695595575569193046.
Full textAbstract:
碩士國立臺灣大學
園藝學研究所
92
Early-harvest‘Ponkan’mandarins (Citrus reticulata Blanco cv. ‘Ponkan’) are usually greenish in color. In order to find practical means to enhance yellow coloration of the fruit, the effects of ethylene degreening, simulated low-temperature quarantine treatment, and storage temperature management on coloration were studied. The peel color was visually estimated and expressed as percent yellow coloration followed by instrumental measurement with a color difference meter. The measurements included L*, a*, and b*, and were later converted into a*/b* value, hue angle, and L* value. Green Ponkan had very little color change during a fifteen-day simulated low-temperature quarantine treatment. After the quarantine treatment, Ponkan turned yellow faster at 15℃ than at 10℃ or 20℃. Coloration was slowest at 25℃. Ponkan without low-temperature quarantine treatment also turned yellow faster at 15℃, followed by 10℃, 20℃, and 25℃ in that order. Mature green Ponkan harvested 14 days earlier and stored at 15℃ for 14 days were yellower than similar fruit harvested 14 days later. Degreening treatment with 5 ppm ethylene for 48 hours at 25℃ either before or after low-temperature quarantine treatment accelerated coloration of Ponkan. Ethylene-degreened Ponkan turned completely yellow 5 to 15 days earlier than similar fruit not degreened. Ethylene degreening caused stem and calyx browing in some fruit. Ethylene treatment after low-temperature quarantine treatment caused fewer stem and calyx brownings than ethylene treatment before quarantine treatment, however. Ethylene effectively degreened Ponkan without low-temperature quarantine treatment as well. Ethylene degreened Ponkan either with or without low-temperature quarantine treatment colored equally well at 10℃, 15℃, or 20℃. Both a*/b* and hue angle could indicate the Ponkan peel color more precisely than visually estimated percent coloration. L* value increased concurrently with visually observed coloration percentage in coloring Ponkan until reaching a peak, which coincided with 100% coloration, and then slightly declined corresponding to deepening of yellow color.
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Gutierrez, Arturo 1978. "Low-temperature synthesis and electrochemical properties of aliovalently-doped phosphates and spinel oxides." Thesis, 2014. http://hdl.handle.net/2152/24928.
Full textAbstract:
Lithium-ion batteries are being intensely pursued as energy storage devices because they provide higher energy and power densities compared to other battery systems such as lead-acid and nickel-metal hydride batteries. This dissertation (i) explores the use of a low-temperature microwave-assisted synthesis process to obtain aliovalently-doped lithium transition-metal phosphates and lower-valent vanadium oxide spinels, some of which are difficult to obtain by conventional high-temperature processes, and (ii) presents an investigation of the electrochemical properties of the aliovantly-doped phosphate cathodes and doped lithium manganese oxide and oxyfluoride spinel cathodes in lithium-ion batteries. Following the introduction and general experimental procedures, respectively, in Chapters 1 and 2, Chapter 3 first focuses on understanding of how the inductive effect and structural features in lithium transition-metal borate, silicate, and phosphate cathodes affect the M²⁺ʹ³⁺redox energies. It is found that the magnitude of the voltages delivered by the polyanion cathodes can be predicted based simply on the coordination of the transition-metal ion. Furthermore, the differences in the voltages delivered by the phosphates and pyrophosphates are explained by considering the resonance structures and their contribution to the covalency of the polyanion. Chapter 4 presents a low-temperature microwave-assisted solvothermal process to substitute 20 atom % V³⁺ for Mn²⁺ in LiMnPO₄. It is shown that the solubility of vanadium in LiMnPO₄ decreases upon heating the doped samples to ≥ 575 °C, demonstrating the importance of employing a low-temperature process to achieve aliovalent doping in LiMnPO₄. It is further demonstrated that by increasing the vanadium content in the material, the discharge capacity in the first cycle could be increased without any additional carbon coating. Subsequent X-ray absorption spectroscopy data reveal that the better performance is facilitated by enhanced Mn-O hybridization upon incorporating vanadium into the lattice. Chapter 5 explores the influence of various factors, such as the oxidation state of Mn, electronegativity of the dopant cation Mn+, and the dissociation energy of M-O bond, on the electrochemical properties of cation-doped oxide and oxyfluoride spinel cathodes. As an extension, Chapter 6 presents the effect of processing conditions on the surface concentration of the dopant cation Mn+. Chapter 7 presents an extension of the low-temperature microwave-assisted synthesis process to obtain AV₂O₄ (Mg, Fe, Mn, and Co) spinel oxides. The method is remarkably effective in reducing the synthesis time and energy use due to the efficiency of dielectric heating compared to conventional heating. The ability to access V³⁺ is facilitated by the relative positions of the energy levels of the cations in solution, which is lower than that in the solid, and the use of a strong reducing solvent like TEG. Finally, Chapter 8 provides a summary of the salient findings in this dissertation.text
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Cheng, Yu-Chuan, and 鄭玉專. "Low-temperature storage effects on sugar content, respiration and quality of Lycoris aurea Herb. cut flowers." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/14277061587163037175.
Full textAbstract:
碩士臺灣大學
園藝學研究所
95
Golden spider lily (Lycoris aurea Herb.) belongs to the Lycoris genus, Amaryllidaceae. It is a flowering bulb native to Taiwan. The plant flowers from late-August to mid-October. Currently, there are very little researches carried out about this cut flower. The postharvest physiology of this flower remains to be explored. The object of this study was to understand the postharvest behaviors of this cut flower, with emphasis on the effect of storage temperature on the quality of flowering. The inflorescence of golden spider lily is an umbel, with an average of 6 – 7 flowers on the scape. The size of each flower bud ranges from 20 mm to 40 mm. When the cut flower was held in water at room temperature, it has an average vase life of 11.5 days, which was determined by the days when two third of the flowers on a scape wilted. Usually, 5 to 6 flowers will open on each scape, and the scape reaches full bloom stage on the 6th day. The lengths of flower buds bear some relationship with the ratio of flower opening, the ratio of abnormal flowers and the vase life. When the flower bud was short, it had lower opening ratio, higher abnormal flower ratio; but stayed longest on the scape. In this study, it was observed that a minimum of 20 mm was required for flower buds to possess the capacity of opening. Once opened, each fully-opened flower will reach similar sizes, the length from the pedicel to the tip of inner petal was about 65 – 68 mm. The respiration rates of golden spider lily cut flower, when held under 0 – 25 ℃, were rather stable from bud stage to fully open. The respiration rates increased as the temperature increase. The highest rate was 20 mg CO2 kg-1hr-1 when held at 25℃ and the lowest rate was 4.7 mg CO2 kg-1hr-1 when held at 0℃. The respiration rate gradually declined when the flowers began to senesce, reaching its lowest value when the scape became flat and lost it value. When the cut flowers of golden spider lily were stored at 5℃ for 5 days then held in deionized water at room temperature for two weeks, the flower opening ratio was 96.7%, abnormal flower ratio was 17.2% and the meaningful vase life, which was the vase life of normal flowers, was 11.5 days. When the cut flowers were stored at 5℃ for 10 days, the flower opening ratio was 90%, abnormal flower ratio was 27.6% and the meaningful vase life was 10 days. When the storage period extended to 15 days, the flower opening ratio was 87.5%, but the abnormal flower ratio increased to 57.4% and the meaningful vase life was reduced to 8.5 days. Therefore, it is concluded that the maximum storage period of golden spider lily cut flower at 5℃ was 10 days. When the cut flowers were held at 10℃ or higher, the flower buds opened gradually during the storage period and the incidence of decay increased, resulting lower flowering quality after storage. Cold storage did not affect the sizes of fully opened flowers, the length from the pedicel to the tip of inner petal was about 64 – 70 mm. It was observed that after cold storage the cut-end of scapes tend to crack when held in vase, the occurrence of cracking did not correlate with storage temperature or with duration. Sucrose was found to be the major carbohydrates in the flower buds of golden spider lily. As the flower bud elongates, the concentration of fructose began to increase gradually. When the flowers began to open, fructose was the major carbohydrates and sucrose gradually decreased. In the scape, fructose and glucose were the major carbohydrates, with small amount of sucrose present. During storage, the fructose and glucose in the scape decreased, and the sucrose concentration increased rapidly in parallel with storage temperature and duration.
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Shye, Der-Chi, and 史德智. "Low-Temperature Processing Techniques Applied on Barium Strontium Titanate Films for the Applications of DRAM Storage Capacitors." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/85373278879314570415.
Full textAbstract:
博士國立交通大學
電子工程系所
93
The characteristics of (Ba, Sr)TiO3 thin films, prepared by novel techniques of low temperature treatments, were systematically studied in this thesis. Pt/TiN/Ti/Si substrates were applied on each sample to simulate the real capacitor over bit-line (COB) structure of dynamic random access memory (DRAM). (Ba, Sr)TiO3 (BST) films were sputtered by radio frequency (RF) magnetron system with dual targets at low substrate temperature, lower than 450oC (340oC at sample surface), and the effects of the process parameters were also investigated. The work pressure, the sputtering gun power and the gas-mixing ratio are the important parameters in the BST film deposition. Material analyses and electrical testing show that the low temperature BST films are significantly affected by those process parameters. The O2/(Ar+O2) mixing ratio (OMR) is a most critical parameter during BST film sputtering. Plasma emission spectra indicate that the deposition rate declines at a higher OMR due to oxide formation on the target surface. The dielectric constant of the BST films can reach a maximum of 364 at 5% OMR. The ten-year lifetime of the time-dependent dielectric breakdown (TDDB) implies that the reliability of the capacitor can be enhanced at a higher OMR due to the compensation of oxygen vacancies and smaller grain sizes. Current-voltage analysis indicates that the leakage current of the Pt/BST/Pt capacitor is limited by Schottky emission (SE)/Poole-Frenkel emission (PF) at a lower/higher applied field, accordingly. The applied field boundary between SE and PF shifts toward higher field as OMR increases. Moreover, an energy-band model was proposed and this leakage mechanism was also discussed. Post low-temperature treatments were applied on the BST films to further improve their crystallinities and electrical properties. A novel process, KrF excimer laser annealing (ELA) at the wavelength of 248 nm, had been undertaken to implement BST films at a process temperature of 300o C to avoid the steep thermal gradient in thin films. The dielectric constant of the amorphous (α) BST film was remarkably enhanced from 80 to over 250 after ELA treatment. The optical testing and the heat conduction analyses indicate that the underlayer films and devices cannot be damaged during ELA treatment due to a very shallow light absorption depth (20 nm) of the BST film at the wavelength of 248-nm. Besides, the laser energy fluence and film thickness greatly influence the thermal conduction and the temperature distribution within the BST films. In the meanwhile, the as-deposited films revealed (mm0) preferred orientation, and, intriguingly, the preferred orientations changed into (m00) and (mmm) after ELA treatments. The optical and the high frequency properties may be affected by this preferred-orientation change. However, although the ELA can perform “shallow-depth annealing” for BST thin film, the degradation of upper surface is strongly influenced by the laser energy fluence. Hence, the leakage current will be significantly affected by the energy fluence of the laser. The leakage current of the ferroelectric film increases after sputtering process and post ELA treatment, but post oxygen plasma treatment can effectively improve the BST film surface to suppress the leakage at low processing temperature of 250oC. According to the analysis results in this thesis, the oxygen plasma treatment can effectively passivate the oxygen vacancies of BST films, decreasing the leakage currents. The leakage current can be reduced as many as two orders of magnitude under proper control of plasma conditions. The characteristics of the dielectric reliability, TDDB, can be also improved by this treatment due to the compensation of the surface oxygen vacancies. In addition, a nano-scaled chromium (Cr) layer is applied onto (Ba, Sr)TiO3 (BST) thin film capacitor as an inter-layer to enhance thermal stability of capacitance and suppress leakage current. Temperature coefficient of capacitance (TCC) using this BST/Cr/BST (200nm/2nm/200nm) multifilm can achieve 30% lower than that using BST mono-layer (400nm) film. Besides, the leakage current can be also greatly suppressed by applying this nano-scaled Cr layer onto BST thin film capacitor. TCC and leakage current behave as functions of Cr thickness, so the optimal properties can be obtained with the Cr thickness of 2nm. Microstructure analysis suggests that the interfacial continuity strongly influences the TCC and leakage property due to scattering centers and series capacitance formed at imperfect interface. The correlated mechanisms between electric and material properties are systematically investigated in this work. BST thin film can be the most promising candidate for Giga-bit generation cell capacitor, because the low temperature processes can be compatible to the IC’s integration. In this thesis, the optimal properties of the BST films can be obtained by adjusting process parameter, applying post treatments and using thermal stabilization structures to achieve thorough low-temperature processes.
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Kok, Richard Dean. "Enhancement of 'Hass' avocado shelf life using ultra-low temperature shipping or 1-MCP treatment and cold chain management." Thesis, 2011. http://hdl.handle.net/10413/8653.
Full textAbstract:
Avocados are becoming an increasingly important crop in South Africa, where the main producing areas include Limpopo, Mpumalanga and KwaZulu-Natal provinces. The South African avocado industry faces considerable challenges including increasing competition exporting avocados, particularly to the European market. The processes involved to export avocados has markedly improved over the past two decades, however there is always room for improvement and it is necessary to remain competitive on a global scale. Issues such as fruit being partially soft on arrival, quality defects and cold chain management breakdown are still present. It is necessary to investigate new aspects of cold storage such as extending the storage period and understanding the physiological aspects involved. To improvement such issues, an investigation was conducted on ultra-low temperature shipping (1°C) as well as the use of 1-MCP; the implementation of deliberate cold chain breaks to achieve a better understanding as to the quality influences involved; an extended storage period of 56 days to assess the quality issues and benefits involved; as well as investigating the physiological aspects involved with all above treatments on 'Hass' avocados. An initial study saw early-, mid- and late-season 'Hass' avocados stored at 1°C or 5.5°C for 28 days. Additional treatments included fruit treated and not treated with 1-MCP as well as waxed and unwaxed fruit. Storage at 1°C was comparable with 1-MCP treatment for both fruit softening in storage and extending the ripening period. Storage at 5.5°C resulted in partial in-transit ripening, if 1-MCP was not used. Early-season fruit incurred the most external chilling injury but overall levels were minimal and not concerning. Mid-season fruit were the most sound in terms of quality. It is suggested that 1°C can be used as a viable economic alternative to 1-MCP for long distance shipping of 'Hass' up to 28 days. The cold chain break trial included a 24 hour delay before cold storage, a deliberate 8 hour break at day 14 of cold storage where fruit were removed from cold storage and a control of 28 days cold storage where no break was involved. Early-, mid- and late-season 'Hass' avocados were stored at 1°C or 5.5°C for 28 days. Additional treatments included fruit treated and not treated with 1-MCP as well as waxed and unwaxed fruit. It was found that cold chain breaks do influence the amount of water loss, fruit softening and days taken to ripen. Storage at 1°C did not entirely negate the effects of cold chain breaks compared with 5.5°C, but did result in fruit which were harder at the end of storage and took longer to ripen. The use of 1-MCP also had advantageous effects with respect to significantly lengthening the ripening period, even when a cold chain break occurred, compared with fruit not treated with 1-MCP. As results of the study differed in some respects to those of previous studies, it is recommended that further work be conducted to determine what fruit or pre-harvest factors affect the fruit physiological changes which take place when cold chain breaks occur. Having the option to make use of an extended storage period would be of benefit to the industry if delays occur and fruit have to be maintained under cold storage. Extended storage of South African avocados, especially at the end of the season would also allow for the option of strategically holding back fruit from the export market in order to extend the supply period. It would not only benefit export options, but would also be highly beneficial to local pre-packers, as it would reduce the need to import fruit from the Northern hemisphere production areas during the South African off-season. Early-, mid- and late-season 'Hass' avocados were stored at 1°C or 5.5°C for 56 days. Additional treatments included fruit treated and not treated with 1-MCP as well as waxed and unwaxed fruit. The combination of 1°C with the use of 1-MCP resulted in a good shelf life as well as maintenance of internal quality and integrity. External chilling injury is of concern for early-season fruit, however, mid- and late-season fruit did not incur extensive damage. It is, therefore, advised that fruit placed in extended storage are marketed through the 'Ready ripe' program to mask any chilling injury on the 'Hass' fruit. Avocados are renown as a "healthy food" due to their nutritional value as well as containing relatively high concentrations of antioxidants. The fruit also contain high amounts of C7 sugars which can act as antioxidants. Additionally, C7 sugars and other antioxidants play important roles in fruit quality. Therefore, it is important to understand how varying storage conditions and treatments affect the levels of these physiological parameters. Treatments of cold chain break/delay included a deliberate 8 hour break at day 14 of cold storage where fruit were removed from cold storage, a 24 hour delay before cold storage and a control of 28 days where no break was involved. A 56 day extended storage period was also used. Early-, mid- and late-season 'Hass' avocados were stored at 1°C or 5.5°C for 28 days. Additional treatments included fruit treated and not treated with 1-MCP as well as waxed and unwaxed fruit. The use of 1-MCP maintained higher levels of antioxidants, ascorbic acid and C7 sugars for both the 28 day and the 56 day storage periods. The 24 hour delay had a
tendency to increase consumption of anti-oxidant and sugar reserves. The use of 1°C resulted in antioxidant and ascorbic acid levels decreasing while maintaining higher sugar levels. Overall, high stress imposed on fruit decreased reserves resulting in poor quality fruit. The use of 1°C and 1-MCP treatments maintained fruit quality.Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
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Duangsuphan, Atitaya, and 陽姍珊. "Low Temperature Induced Chilling Injury and Alleviation Strategy in Jicama (Pachyrhizus erosus (L.) Urban) Tuberous Roots during Storage." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/14488710962378844140.
Full textAbstract:
博士國立中興大學
園藝學系所
105
The purpose of this research was to study the characteristics changes and chilling development, quality changes and the activity of the related enzyme as well as the correlation between ethylene and the chilling damage on the jicama tuberous root during storage under chilling or non-chilling temperatures. The roots stored at 6ºC as chilling condition, and at 20ºC as non-chilling condition, for 30 days. Characteristics of chilling injury were induced by chilling condition, included external decay, internal browning, decreasing of interior tissue lightness (L*) value and total phenolic compound (TPC), and loss of root firmness. The chilling temperature induced membrane damage includes increasing of membrane ion leakage (%), malondialdehyde (MDA) and hydrogen peroxide (H2O2) content. There were significantly increased of phenylalanine ammonium-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) specific activities in severe symptoms of chilling injury. The increasing of external decay and internal browning were highly correlated with increasing of membrane ion leakage (%), MDA content, PAL specific activity, PPO specific activity and decreasing of TPC. For the root stored at 6ºC, 9 days after storing then transferred to higher temperature for another 3 days (15ºC, 20ºC, 25ºC or continuously at 6ºC). The severe symptoms were found in the roots which were transferred to higher temperature, whereas the ethylene production and respiration rates can reduce by low-temperature conditions. Nonlinear Arrhenius plots of respiration were found in the roots stored at various temperatures (1ºC, 3ºC, 6ºC, 9ºC, 12ºC, 15ºC, and 20ºC). The slope of the plot from root and tissue discs decreased with lower temperatures with breaks points at about 9ºC in root and at 7ºC in tissue discs. For the evaluation of ethylene production and respiration rates, roots storing at 6ºC for 12 days. Every 3 days, roots were transferred to 25ºC for evaluation at every 3 hours for 24 or 36 hours. Ethylene production and respiration rate rapidly increased after the root were transferred to higher temperature and tended to decrease afterward. For intermittent warming treatment (IW), jicama tuberous roots were stored at 6ºC for 12.5 days. Continuously, every 2 days, roots were transferred to ambient temperature for 12 hours (after 12 hours, the roots were returned to 6ºC). Intermittent warming treatment reduced ion leakage (%), internal browning, maintained the interior tissue L* value, and showed a good appearance after storage for 12.5 days but did not maintain firmness and reduced external decay. Roots treated with IW showed significant lower in ethylene production and respiration rate than roots storing at 6ºC but these rates were not consistent with the increasing of external decay, internal browning, and membrane ion leakage (%). 1-MCP treatment reduced ethylene production and respiration but increased chilling injury symptoms, such as external decay, internal browning, decreasing of interior tissue L* value, loss of firmness, and decreasing of membrane integrity. These results indicated that ethylene probably does not directly involved in chilling injury symptom development of jicama tuberous root. Hot water treatment (HWT, 50ºC, 53ºC, and 55ºC) suppressed external decay and internal browning development, but none of them could completely prevent all the symptoms. Firmness, lightness value, and H2O2 content were not affected by the HWT. Root treated with 55ºC hot water was lower in ion leakage percentage and malondialdehyde. Nonetheless, statistics showed that there has no significant difference as compared to control. Hot water treatment can also maintain higher level of total phenolic compound. After transferring to ambient temperature rate of ethylene production was significantly reduced by the HWT, but rate of respiration was reduced only in 55ºC HWT. PAL, PPO, and POD specific activity were significantly reduced by the 53ºC HWT. Ferric reducing ability of plasma was maintained by the 55ºC HWT. Superoxide dismutase and catalase specific activity were not affected by any treatment of the HWT. Lastly, the 50ºC HWT maintained high level of ascorbate peroxidase specific activity. Low O2 treatments can reduce browning discoloration, maintain interior tissue L* value and delay weight loss of root but did not affect the root firmness. The best browning prevention was found in root treated with 0% O2, nevertheless, high decay was also found in this treatment. Moreover, 0% O2 treatment damaged the root cell membranes, which give the rise of ion leakage (%) and decay.
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Kao, Chi-Fen, and 高啓雰. "Effect of Low Temperature and Package on ‘Sweet Green’ and ‘Rainbow’ Guava (Psidium guajava L.) Fruit Quality after Storage." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/b63rp3.
Full textAbstract:
碩士國立中興大學
園藝學系所
107
To solve the problem of low storage quarity of guava in summer season.The objective of the present study is to investigate the effect of low temperature and different packaging on the storage quality of ''Sweet Green'' and ''Rainbow'' guava. The results show that the storage capability of ‘Sweet Green’ was comparable to that of ‘Jen Ju’. Upon low temperature storage, while the fruit firmness and total titratable acid content decreased slowly in both varieties, the total soluble solid and ascorbic acid content of ‘Sweet Green’ were higher than ‘Jen Ju’. The chlorophyll fluorescence of both varieties dropped after storage at 1℃ for 21 days, but the value reversed mildly after return to 20℃ for 3 days. Although storage at 1℃ and 2℃ for 28 days could lead to chilling injury in both ‘Jen Ju’ and ‘Sweet Green’ fruits, ‘Sweet Green’ stored at 2℃ and 5℃ for 28 days maintained a desirable the chlorophyll fluorescence of at above 0.7, and showed the lowest ion leakage percentage. In addition, the organoleptic qualities test of ‘Sweet Green’ remained 4.5 point . The results above suggested that ‘Sweet Green’ is more tolerant to low temperature storage, which implicating export potential with long-term transportation. To evaluate the potential of edible coating to improve guava storage ability in summer, 0.2 %, 0.5 %, and 1 % of Sucrose fatty acid ester and 0.5 % and1 % of chitosan were used in the present study. After 14 days storage at 1℃ for for quarantine and long-term storage at 1 °C for 21 days and 2°C for 28 days, respectively, no significant differences was found between each group. Moreover, coating treatments induced anaerobic respiration during storage and the subsequent metabolites impaired the appearance of the guava resulting in loss of the commercial value. Taken together, the aforementioned concentrations of the coating materials may not besuitable for both ''Jen Ju'' and ''Sweet Green'', further studies are required to determine the optimal concentration for storage of guava. We also applied PE packages at 0.02 mm, 0.03 mm, 0.04 mm, and 0.08 mm for coating to examine the effect of different thicknesses of PE packages on the fruit quality of ‘Sweet Green’. The result demonstrated that the different thicknesses had no impact on weight loss, firmness, total soluble solids, total titratable acid, and ascorbic acid content. Regarding the financial cost, the favorable thickness of PE bags for the packaging of ''Sweet Green'' is 0.02 mm under 5°C storage. To promote multiple varity choices,''Rainbow'' guava is favored by some consumers for its red color and rich in carotenoids and lycopene. In this test, a 6-matured and 8-matured ''Rainbow'' was stored at 2°C for 28 days followed by storage at 20°C for 1 to 3 days to simulate transportation to Canada. The results showed that the fruit had punctiform softening at 2°C for 28 days. After 1 day of transport to 20°C, while some fruits appeared anthrax symptoms, most of them were able to maintain 70% salability, but after 3 days transferring to 20℃,both maturity had already lost its commercial value.It was considered that this varieties had to keeping cooling condition to maintain the quality.
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Chien, An-Chi, and 簡安祺. "Effects of Copper Sulfate and Low Temperature Storage on Physical-chemical Characteristics and Internal Browning of Tainung No.17 Pineapple Fruits." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/73857392717204257883.
Full textAbstract:
碩士國立中興大學
園藝學系所
105
Pineapple fruits stored at low temperature are easy to develop chilling symptoms, leading to internal browning and fruits quality decreasing. Because there are no external symptoms on affected fruits, it may cause losses of business reputation and profits. The main objective of this study was to investigate whether an increase of copper level in ‘TN17’ pineapples pulp will cause an increase in internal browning incidence, and to analyze the occurrence of internal browning of ‘TN17’ pineapple fruits which were stored at different low temperatures to provide information about the key factor to internal browning development. After spraying copper sulfate on‘TN17’ pineapple fruits in the field, copper concentrations in the shell were significantly higher than in the pulp. After stored at 8℃ for 1 week and followed at room temperature for 2 days, copper level of flesh slighity increased with internal browning symptom occurrence. Both copper level and internal browning index increased in ‘TN17’ pineapple fruits which were dipped in copper sulfate solution and stored at 8℃ for 1 week followed at room temperature for 2 day. Low temperature storage can delay ‘TN17’ pineapple skin color development. No internal browning appeared in fruits stored at low temperature for 1 week, however, it occurred in fruits stored at low temperature for 1 week followed by 4 days at room temperature. Internal browning index was significantly increased in fruits stored at 4℃, followed by fruits stored at 12℃ and only slightly increased in fruits stored at 8℃. More severe internal browning was found in fruits stored at low temperature for 2 week, followed at room temperature for 4 days. Fruits stored at 12 ℃ for 2 weeks followed by 4 days at room temperature had the highest internal browning index, compared with 4℃ and 8℃ treatments. Calcium ions moved from inner pulp to outer pulp during storage may affect the tolerance of the ‘TN17’ pineapple inner pulp cells to low temperature stress. The copper level was significantly higher in pineapple fruits with more severe internal browning. In this study, ‘TN17’ pineapples stored at 4℃ for 2 weeks followed by 4 days at room temperature had slightly internal browning, but fruit section was seriously turned brown after treated with PPO substrate. The longer low temperature storage period, the higher PPO activity was found after 4 days at room temperature. The total protein content of fruits decreased during low temperature storage, and then increased after stored at room temperature. The bromelain activity increased after stored at low temperature, then decreased after moved to room temperature with internal browning occurrence. The relationship between bromelain activity and internal browning is worthy of further study. Taken together, for ‘TN17’ pineapples, it is not that the lower storage temperature, the more internal browning occurrence. In this study, the results showed that 8℃ storage had lower internal browning incidence than 4℃ and 12℃ storage. In combination with waxing or hot water dipping before storage, pineapples may have better storage quality.