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Investigation of a Theoretical Magnetic Refrigeration CycleSnead, Joshua D. 01 May 2013 (has links)
This research paper studies the concept of developing a different type of freezer rather than vapor-compression for Dippin' Dots, a company who sells frozen goods. The freezer in question is a magnetic freezer that works by removing the compressor and bringing in magnetocaloric materials, which provide cooling by being subjected to a magnetic field. Many possibilities for improvements are available from this technology including a safer more environmentally benign fluid, a higher efficiency, and a possible cost savings. A theoretical model was designed and efficiency calculations and a cost analysis were both performed to determine if there were any improvements and if constructing a prototype freezer was feasible. The coefficient of performance of the designed freezer had the theoretical capability of being up to 5 times that of the vapor-compression freezer, but with the pumps found to complete the design this high number fell significantly short. The price to build a prototype was calculated to be around $7,050. After considering the data building a magnetic freezer prototype does not seem feasible. Although this freezer does not seem reasonable, the magnetic refrigerator technology seems applicable for other uses and is capable of developing in the future.
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Cryopreservation of Equine Spermatozoa: Identification of Good and Poor Freezer Stallions and Effect of Sperm Density Per StrawFahad, Abed Sharqy 15 December 2012 (has links)
This study was carried out primarily to evaluate the cryo-tolerance of equine semen from four stallions through assessing the spermatozoa motion characteristics with Computer-Assisted Sperm Analysis (CASA). Four stallions were collected during the breeding season (summer). For each ejaculate, fresh and cryopreserved samples were taken for sperm motility characteristics evaluation. Data analysis demonstrated that sperm cells of stallions were significantly affected by (P<0.05) cryodamage. Stallion (A) was cryotolerant, and was classified as a good freezer, whereas stallion (D) was not and classified as a poor freezer regardless of the concentration of sperm. In addition, a concentration of 0.4 x 109 sperm cells/ml had higher percentages of rapid sperm and velocity parameters (P<0.05) compared to 0.8 x 109 sperm/ml. Further research is necessary to identify potential biomarkers for good and poor freezer stallions.
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Efeito da colheita fracionada sobre a cinética e viabilidade espermáticas do sêmen refrigerado e congelado de garanhõesOliveira, Sidnei Nunes de. January 2016 (has links)
Orientador: Frederico Ozanam Papa / Resumo: O pênis é o órgão copulador e no garanhão é classificado como sendo músculo cavernoso, em que os espaços cavernosos são preenchidos de sangue durante a ereção. Nos testículos que ocorre a produção espermática, que são transportados pela rete testis até o epidídimo, onde sofrerão maturação, capacidade fertilizante e armazenados até a ejaculação. As glândulas sexuais acessórias são responsáveis pelos fluidos expelidos durante a ejaculação, denominado de plasma seminal, que se misturam às células espermáticas e formam o ejaculado. Cada uma dessas glândulas são responsáveis por uma determinada secreção que vai direcionar o ejaculado equino a ser dividido em três distintas frações: fração pré-espermática, produzida pelas glândulas bulbouretrais e próstata; fração rica em espermatozoides, produzida pelas secreções do epidídimo e por líquidos das ampolas dos ductos deferentes; fração pós-espermática ou fração pobre, formada por espermatozoides remanescentes no canal uretral e líquidos produzidos pelas vesículas seminais, o gel. Durante o processo fisiológico de cópula, ocorrem vários eventos denominados de ereção, em que o garanhão se excita por estímulos, emissão que caracteriza-se pela liberação de espermatozoides dentro da uretra pélvica, seguido da ejaculação com a expulsão do sêmen, o relaxamento e recolhimento do pênis. Normalmente, as colheitas de sêmen equino são realizadas de forma convencional, com vagina artificial fechada, em que todas as frações se misturam. Cada garanh... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The penis is the copulatory organ and in the stallion it is classified as cavernous muscle and the cavernous spaces are filled with blood during erection. In the testicles occurs sperm production, that are transported through the rete testis to the epididymis, where they will suffer maturation, fertilizer capacity and will be stored until ejaculation. The accessory sex glands are responsible for the expelled fluids during ejaculation, named seminal plasma that are mixed with sperm cells and form the ejaculate. Each of these glands are responsible for a certain secretion that will divide equine semen into three distinct fractions: pre-sperm fraction, produced by the prostate and bulbourethral glands; rich fraction in sperm, produced by epididymal secretions and liquids from ampoules of the vas deferens; post-sperm fraction or poor fraction, consisting of sperm remaining in the urethral canal and liquids produced by the seminal vesicles, the gel. During the physiological process of mating, several events occur named erection, in which the stud is excited by stimuli emission which is characterized by the release of sperm into the pelvic urethra followed by ejaculation with the expulsion of semen, relaxation and gathering the penis. Typically, horse semen collections are performed in the conventional way, with a closed artificial vagina, where all the fractions are mixed. Each stud has individual characteristics related to the maintenance of sperm cells during the cryopreservatio... (Complete abstract click electronic access below) / Mestre
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Energioptimering hos Freezing Food AB : Fallstudie i luftväxling och värmeöverföringNilsson, Dan, Magnusson Österberg, Patrik January 2017 (has links)
Arbetet handlade om att utreda energibehovet till följd av en industriport mellan ett fryslager och en utlastningsterminal, samt utreda om anläggningens golvvärme kan arbeta med sänkt temperatur för att minska uppvärmingen av fryslagret, båda delarna med syftet att identifiera energiförluster och kunna sänka energiåtgången. Energiförlusten till följd av porten identifierades genom uppmätning av luftflöden för att sedan beräknas över ett år med hjälp av en teoretisk modell. För att undersöka golvvärmens driftsparametrar gjordes en litteraturstudie för att bestämma ifall det vore tillrådligt att sänka dess arbetstemperatur. Slutsatsen blev att portens öppetvarande under år 2016 resulterade i omkring 145MWh i rent termisk energiförlust. Anläggningens vattenburna golvvärme drivs vid cirka 10-12°C vilket är enligt praxis och att en förändring av temperaturen därför inte kan rekommenderas. / This thesis was examining the energy demand due to an industrial gate dividing a freezer warehouse and it’s adjacent loading bay, as well as determining whether the facility’s sub-floor heating could be operated at a lower temperature setting in order to decrease the heat transfer into the freezer, both of which with the purpose to identify energy losses and possibly lower the total energy demand. The energy losses due to the gate were identified by measuring airflow and then calculate the loss over a whole year by means of a theoretical model. To examine the operating parameters of the sub-floor heating, a literature study was conducted in order to determine whether it would be feasible to lower its temperature. The conclusion was that the opening of the gate during year 2016 resulted in about 145MWh of purely thermal energy loss. The facility’s waterborne sub-floor heating is operated at around 10-12°C, which is according to practice, and a change of temperature cannot be recommended.
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Automated freeze-thaw cycles for decellularization of tendon tissue: a pilot studyRoth, Susanne Pauline, Glauche, Sina Marie, Plenge, Amelie, Erbe, Ina, Heller, Sandra, Burk, Janina 31 August 2017 (has links)
Background: Decellularization of tendon tissue plays a pivotal role in current tissue engineering approaches for in vitro research as well as for translation of graft-based tendon restoration into clinics. Automation of essential decellularization steps like freeze-thawing is crucial for the development of more standardized decellularization protocols and commercial graft production under good manufacturing practice (GMP) conditions in the future. Methods: In this study, a liquid nitrogen-based controlled rate freezer was utilized for automation of repeated freeze-thawing for decellularization of equine superficial digital flexor tendons. Additional tendon specimens underwent manually performed freeze-thaw cycles based on an established procedure. Tendon decellularization was completed by using non-ionic detergent treatment (Triton X-100). Effectiveness of decellularization was assessed by residual nuclei count and calculation of DNA content. Cytocompatibility was evaluated by culturing allogeneic adipose tissue-derived mesenchymal stromal cells on the tendon scaffolds. Results: There were no significant differences in decellularization effectiveness between samples decellularized by the automated freeze-thaw procedure and samples that underwent manual freeze-thaw cycles. Further, we inferred no significant differences in the effectiveness of decellularization between two different cooling and heating rates applied in the automated freeze-thaw process. Both the automated protocols and the manually performed protocol resulted in roughly 2% residual nuclei and 13% residual DNA content. Successful cell culture was achieved with samples decellularized by automated freeze-thawing as well as with tendon samples decellularized by manually performed freeze-thaw cycles. Conclusions: Automated freeze-thaw cycles performed by using a liquid nitrogen-based controlled rate freezer were as effective as previously described manual freeze-thaw procedures for decellularization of equine superficial digital flexor tendons. The automation of this key procedure in decellularization of large tendon samples is an important step towards the processing of large sample quantities under standardized conditions. Furthermore, with a view to the production of commercially available tendon graft-based materials for application in human and
veterinary medicine, the automation of key procedural steps is highly required to develop manufacturing processes under GMP conditions.
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A FORTRAN 77 simulation of a low temperature storage freezer utilizing a non-azeotropic refrigerant blendCraddock, David M. January 1995 (has links)
No description available.
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Simulation of a storage freezer operating with a binary nonazeotropic refrigerant blend Part I. Equation of state cycle selection compressor model and air-cooled condenser modelTipton, Russell C. January 1989 (has links)
No description available.
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Controle gerencial e análise de custos dos frigoríficos abatedouros de bovinosFerreira, Reginaldo Fernandes 30 August 2006 (has links)
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Previous issue date: 2006-08-30 / This paper aims the construction of a managerial model to decision making
based on the variable cost to the bovines slaughterhouse freezer developed into a
conjoint production with the purpose of short term decision because of the industrial
process speed.
The development of this work starts approaching questions over the environment
which involves the bovines slaughterhouse organizations in Brazil, demonstrating their
functioning, economic aspects of this activity, and their importance in the Brazilian
economy.
Based on bibliography, it will be demonstrated the existent cost methodologies,
their main concepts, the advantages and disadvantages of each one of them.
The next stage, via bibliography research, it searches to characterize the conjoint
production as a particular case predominantly of continuous production. It demonstrates
its concepts, ways of cost appropriation more used, nevertheless, emphasizing its
inadequate way to the decision making.
This work developed practical cases so that are presented common operations to
the activity, operations which lead, consequently, the company to the necessity of a
decision making. To the decision making, it is adopted the variable cost which will be
taken as a base on the contribution margin.
Besides the contribution margin, others decisions are taken based on incremental
contribution margin because of the separation point that obligates to be considered only
the incremental costs and revenues.
This work shows a defined point in which the concepts presented by the
researched bibliography are not possible to be applied on the decision making over the
cost analysis in practice in the bovines slaughterhouses.
Based on the contribution margins and fixed costs, this paper also points out
how the decision makings can be taken over the minimum quantity of heads of cattle
that the slaughterhouse freezer must slaughter and the minimum of pieces to bone and
export / Este trabalho objetiva a construção de um modelo gerencial para a tomada de decisão
baseado no custeio variável para os frigoríficos abatedouros de bovinos, desenvolvido em
produção conjunta com a finalidade de decisões de curto prazo por causa da rapidez do
processamento industrial.
O desenvolvimento do trabalho inicia-se abordando questões acerca do ambiente que
envolve as organizações abatedouro de bovinos no Brasil, demonstrando seu funcionamento,
os aspectos econômicos dessa atividade e a importância que têm na economia brasileira.
Através de respaldo bibliográfico, são explicitadas as metodologias de custeio
existentes, seus principais conceitos, as vantagens e desvantagens de cada uma delas.
A etapa seguinte, via pesquisa bibliográfica, busca caracterizar a produção conjunta
como um caso particular predominantemente de produção contínua. Demonstra seus
conceitos, formas de apropriação de custos mais utilizadas, porém, frisando sua inadequação
para a tomada de decisões.
O trabalho desenvolveu casos práticos, em que são apresentadas operações comuns à
atividade, operações que levarão, conseqüentemente, a empresa à necessidade de tomar
decisões. Para a tomada de decisões é adotado o custeio variável no qual elas são tomadas
com base na margem de contribuição.
Além da margem de contribuição, outras decisões são tomadas com base na margem
de contribuição incremental por causa do ponto de separação que obriga a serem levados em
conta somente os custos e as receitas incrementais.
O trabalho mostra determinado ponto em que os conceitos apresentados pela
bibliografia pesquisada não são possíveis de serem aplicados nas tomadas de decisões sobre
a análise de custo na prática nos abatedouros de bovinos.
Com base nas margens de contribuição e custos fixos, este trabalho, também, aponta
como podem ser tomadas as decisões sobre a quantidade mínima de cabeças que o frigorífico
deverá abater e o mínimo de peças a desossar e exportar
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Improving the Flavor of Ground Beef by Selecting Trimmings from Specific LocationsHarbison, Amanda 1989- 14 March 2013 (has links)
We hypothesized that carcass subcutaneous fat location would affect sensory and quality traits. Five carcass fat sources were tested: brisket, chuck, plate, flank, and round. Ground beef was formulated using each fat source and extra-lean beef trim (>95% lean) to contain 80% lean trim and 20% fat trim. Patties (100 g) were evaluated for color, lipid oxidation, fatty acid composition and consumer evaluation. Flavor was analyzed using a Gas chromatography with mass spectrometry (GC/MS) on the headspace above a cooked (74 degrees C) patty in a heated (60 degrees C) 473 mL glass jar with a solid phase micro-extraction (SPME) fiber. Color, thiobarbituric acid reactive substance assay (TBARS), consumer sensory, and cook/freezer loss data showed no differences (P > 0.05) among carcass locations. Percentage stearic acid was lower (P = 0.044) in the brisket than in the chuck and flank. The brisket was higher in percentage cis-vaccenic acid (P = 0.016) and in the saturated fatty acid to monounsaturated fatty acid ratio (P = 0.018), and lower (P = 0.004) in the percentage of total saturated fatty acids than all other sources of subcutaneous fat. Butanedione was highest (P = 0.013) in the flank and plate fat. Brisket tended to be higher (P = 0.054) than flank, plate, and round in 1-octen-3-ol. Brisket was higher (P = 0.008) than chuck, flank, and round, but not different (P > 0.05) than plate in octanedione. Brisket was higher (P = 0.003) than all other sources for beefy aroma. Flank was higher (P = 0.047) than chuck and round for chemical aroma. Brisket was higher (P = 0.004) than all other sources except flank for floral aromas. Plate was higher (P = 0.029) than all other sources for heated oil aromas. For secondary aroma descriptor, round was higher (P < 0.001) than flank, plate, and chuck for dairy. While differences in some key fatty acids and aromatics existed among carcass locations, when the fat was diluted with a common lean source, fat source did not have a negative effect on sensory or quality traits. Therefore, formulating ground beef using subcutaneous fat from specific locations on a carcass may improve the beef aromatics without negatively affecting sensory or quality traits.
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Tepelné čerpadlo pro ohřev teplé vody / Heat pump water heaterMazálek, Karel January 2018 (has links)
This Master's thesis deals with reusing waste heat from the kitchen and .cold rooms of a restaurant, as a source of heat for heat pump water heater. The first part is about basic principles and theory which is needed to understand the function of heat pump and possibilities of reusing wasted heat. In the other parts, there are calculations and designs not only of a heat pump, but also coolers and ventilation unit needed for recycling of heat.
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