100,117 research outputs found
An experimental and theoretical investigation of a wick-type solar still for water desalination
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Solar distillation using a wick-type solar still was investigated theoretically and experimentally. A tilled flat plate wick-type solar still was designed and constructed.
Charcoal cloth was used as an absorber/evaporator material and for saline water transport. A theoretical model for the performance of the wick-type solar still has been developed and analysed. It investigates the effect of various factors on the still productivity. A Fortran computer program has been developed and a finite difference technique was used to solve the main equations and to determine related parameters.
Indoor experimental testing was carried out to investigate the effect of input water flow rate and salinity on the still productivity together with the variation of the solar still efficiency with absorber temperature. The tests were conducted using the irradiance from a lamp array. Outdoor testing was carried out with and without a V-trough solar concentrator on clear days in summer and winter. Representative daily efficiencies of the still with and without the solar concentrator were about 60% and 50% respectively on clear days in summer. The solar absorptances of samples of charcoal cloth and blackened hessian cloth were determined before and after environmental exposure. The solar reflectances of samples of 3M Scotchcal Films and aluminised plastic (as potential reflecting materials for the concentrator mirrors) were investigated before and after environmental exposure and also exposure to elevated temperatures and humidities. It has been concluded that: charcoal cloth is a good material for use as an absorber/evaporator and also as a water transport medium. Increase of the input water mass flow rate leads to a reduction in the efficiency of the wick-type solar still. The still efficiency decreased linearly with Increase of salinity of the input saline water. The productivity of the still Increases linearly with absorber temperature. The best absorber-cover separation Is found to be in the range 20-25 mm. Wind speed has no significant effect (up to about 10 m/s) on the performance of a well sealed still. The transmittance of the glass cover has a strong influence on the still efficiency. Use of the solar concentrator with the inclined wick-type solar still leads to a greater fractional increase In still productivity on clear days in winter than on clear days in summer
Modeling and Design Optimization of Ultra-Thin Vapor Chambers for High Heat Flux Applications
No full textPassive phase-change thermal spreaders, such as vapor chambers have been widely employed to spread the heat from small-scale high-flux heat sources to larger areas. In this paper, a numerical model for ultrathin vapor chambers has been developed, which is suitable for reliable prediction of the operation at high heat fluxes and small scales. The effects of boiling in the wick structure on the thermal performance are modeled, and the model predictions are compared with experiments on custom-fabricated vapor chamber devices. The working fluid for the vapor chamber is water and a condenser side temperature range of 293 K–333 K is considered. The model predictions agree reasonably well with experimental measurements and reveal the input parameters to which thermal resistance and vapor chamber capillary limit are most sensitive. The vapor space in the ultrathin devices offers significant thermal and flow resistances when the vapor core thickness is in the range of 0.2 mm–0.4 mm. The performance of a 1-mm-thick vapor chamber is optimized by studying the variation of thermal resistance and total flow pressure drop as functions of the wick and vapor core thicknesses. The wick thickness is varied from 0.05 to 0.25 mm. Based on the minimization of a performance cost function comprising the device thermal resistance and flow pressure drop, it is concluded that the thinnest wick structures (0.05 mm) are optimal for applications with heat fluxes below 50 W/cm2, while a moderate wick thickness of 0.1 mm performs best at higher heat flux inputs (\u3e50 W/cm2)
Joshua Davis: Author of Spare Parts
No full textCitation: K-State First (2016). Joshua Davis: Author of Spare Parts [Flier]. Manhattan, Kansas: K-State First.Flyer advertising Joshua Davis's author talk at Kansas State University
Steven Johnson Author Talk Poster
No full textK-State Book NetworkA poster advertising an author talk by Steven Johnson at Kansas State University on September 3, 2014. Steven Johnson's book "The Ghost Map" was the 2014-2015 common book
Lamp Wick.
No full textPatent for a new and improved wick for oil lamps. This design "consists in forming the lamp-wick of one or more layers of mineral wool inclosed in a textile material, the whole being sewed together by a series of parallel longitudinal stitches" (lines 18-22). Employing textile material represents an improvement in capillarity over previous wicks made with refractory cement
Wick polynomials in non-commutative probability: A group-theoretical approach
No full textWick polynomials and Wick products are studied in the context of non-commutative probability theory. It is shown that free, boolean and conditionally free Wick polynomials can be defined and related through the action of the group of characters over a particular Hopf algebra. These results generalize our previous developments of a Hopf algebraic approach to cumulants and Wick products in classical probability theory
Wick polynomials in non-commutative probability
No full textWick polynomials and Wick products are studied in the context of non-commutative probability theory. It is shown that free, boolean and conditionally free Wick polynomials can be defined and related through the action of the group of characters over a particular Hopf algebra. These results generalize our previous developments of a Hopf algebraic approach to cumulants and Wick products in classical probability theory
The effect of the dipeptide, Lys-Gly, supplement on growth, muscle proteins and PEPT1 gene expression in juvenile yellow perch
No full textThe objective of the present study was to
examine the effect of a wheat-gluten-based diet supplemented
with the indispensable amino acid source in the
form of freeamino acid or dipeptide on growth, intestine
oligopeptide transporter, PepT1, transcript levels using
real-time RT-PCR, and muscle protein expression in
yellow perch Perca flavescens juveniles. Yellow perch
(initial size*0.3 g) were randomly distributed into 12
glass aquaria, 60 fish per tank. Fish were fed 4 diets:
wheat-gluten based diet supplemented with lysine–
glycine dipeptide (LG), wheat-gluten based diet supplemented
with free lysine (FL), diet not supplemented
with lysine (NL; negative control) and a commercial
diet (BO). Fish were fed at 90 % satiation level and the
rate was re-adjusted to be equal across all treatments
based on each day’s projected change in weight gain.
It amounted to 3 % of the biomass per day for the first
14 days and 4–5 % until the end of the experiment.
After 55 days of the experiment the mean weight of
juvenile yellow perch fed the LG diet was larger
compared to the NL diet fed group. There was no
difference, however, between LG, FL, and BO groups
(1.35 ± 0.11 g; 1.31 ± 0.03; 1.16 ± 0.10 g, respectively).
Fish subjected to FL treatment showed an
increase in the amount of PepT1 transcripts compared to
the NL group value. The LG diet was associated with a
significant increase in PepT1 mRNA transcript levels,
compared with both FL and NL diets fed fish.We have
also cloned and sequenced full-length cDNA representing
yellow perch PepT1. The cDNA sequence (Gene-
Bank: accession no.GQ906471), encompasses a total of
2,956 base pairs (bp) including a 50-untranslated region
of 94 bp, an open reading frame of 2,190 bp, and a 30-
untranslated region of 672 bp. The predicted 12 transmembrane
domains and the 3D structure of the protein
(729 amino acids) are presented. Proteomic fingerprinting
showed that thirteen electrophoretically resolved
protein/peptide bands from the muscle sarcoplasmic
fraction were significantly different across treatments
suggesting that muscle protein expression was influenced
by dietary treatments
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0-G experiments with advanced ceramic fabric wick structures
No full textBoth Air Force and NASA future spacecraft thermal management needs span the temperature range from cryogenic to liquid metals. Many of these needs are changing and not well defined and will remain so until goals, technology, and missions converge. Nevertheless, it is certain that high-temperature (> 800 K) and medium-temperature (about 450 K) radiator systems will have to be developed that offer significant improvements over current designs. This paper discusses experiments performed in the lower temperature regime as part of a comprehensive advanced ceramic fabric (ACF) heat pipe development program. These experiments encompassed wicking tests with various ceramic fabric samples, and heat transfer tests with a 1-m long prototype ACF water heat pipe. A prototype ceramic fabric/titanium water heat pipe has been constructed and tested; it transported up to 60 W of power at about 390 K. Startup and operation both with and against gravity examined. Wick testing was begun to aid in the design and construction of an improved prototype heat pipe, with a 38-{mu}m stainless steel linear covered by a biaxially-braided Nextel (trademark of the 3M Co., St. Paul, Minnesota) sleeve that is approximately 300-{mu}m thick. Wick testing took place in 1-g; limited testing in 0-g was initiated, and results to date suggest that in 0-g, wick performance improves over that in 1-g
Some Experiments on Screen Wick Dry-out Limits
No full textDry-out limits of screen wicks vertically pumping against gravity above an acetone pool were determined in evaporation experiments. As the pumping height shortened, the increase in heat input at dry-out became less than that expected from a fully saturated wick layer. The receding of the evaporating boundary into a sublayer of the wick was postulated, based on the fact that the measured thermal resistance across the wick layer decreased as heat input increased. Such a recess seems to terminate at two layers above the heated wall. A new wicking model taking into account the receding of evaporation boundary could predict the experimental dry-out heat inputs within 10 percent.</jats:p
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