Academic literature on the topic 'Loss-in-Weight Feeder'
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Journal articles on the topic "Loss-in-Weight Feeder"
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Hopkins, Mark. "Loss in Weight Feeder Systems." Measurement and Control 39, no. 8 (October 2006): 237–40. http://dx.doi.org/10.1177/002029400603900801.
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Engisch, William E., and Fernando J. Muzzio. "Method for characterization of loss-in-weight feeder equipment." Powder Technology 228 (September 2012): 395–403. http://dx.doi.org/10.1016/j.powtec.2012.05.058.
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Peterwitz, Moritz, Sina Gerling, and Gerhard Schembecker. "Challenges in tracing material flow passing a loss-in-weight feeder in continuous manufacturing processes." International Journal of Pharmaceutics 612 (January 2022): 121304. http://dx.doi.org/10.1016/j.ijpharm.2021.121304.
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WADA, Kenzo, Hiroshi ITO, and Eiji MORIMOTO. "Control of the Outflow Quantity Discharged Pulsatingly from a Loss in Weight Type Feeder." Transactions of the Japan Society of Mechanical Engineers Series C 58, no. 545 (1992): 120–25. http://dx.doi.org/10.1299/kikaic.58.120.
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Li, Tianyi, James V. Scicolone, Eric Sanchez, and Fernando J. Muzzio. "Identifying a Loss-in-Weight Feeder Design Space Based on Performance and Material Properties." Journal of Pharmaceutical Innovation 15, no. 3 (June 3, 2019): 482–95. http://dx.doi.org/10.1007/s12247-019-09394-4.
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El Kassem, Bilal, Thomas Brinz, Vahid Jenkouk, Yousef Heider, and Bernd Markert. "Design of a vertical Loss-in-Weight feeder prototype with experimental proof of concept validation." Pharmaceutical Development and Technology 26, no. 5 (April 19, 2021): 559–75. http://dx.doi.org/10.1080/10837450.2021.1901915.
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Spire, M. F., J. M. Sargeant, and James S. Drouillard. "Effects of sickness on weight gain and radiant energy loss in recently received feeder cattle." Kansas Agricultural Experiment Station Research Reports, no. 1 (January 1, 2000): 73–74. http://dx.doi.org/10.4148/2378-5977.1805.
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Yadav, Indrajeetsinh K., James Holman, Elizabeth Meehan, Furqan Tahir, Jiyi Khoo, Julian Taylor, Antonio Benedetti, Opeyemi Aderinto, and Gurjit Bajwa. "Influence of material properties and equipment configuration on loss-in-weight feeder performance for drug product continuous manufacture." Powder Technology 348 (April 2019): 126–37. http://dx.doi.org/10.1016/j.powtec.2019.01.071.
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Basarab, J. A., J. R. Brethour, D. R. Zobell, and B. Graham. "Sorting feeder cattle with a system that integrates ultrasound backfat and marbling estimates with a model that maximizes feedlot profitability in value-based marketing." Canadian Journal of Animal Science 79, no. 3 (September 1, 1999): 327–34. http://dx.doi.org/10.4141/a98-094.
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Studies were conducted to evaluate a feeder cattle sorting system for tracking future carcass merit. The Kansas State University (KSU) sorting system combines initial body weight, ultrasound backfat thickness and marbling score with economic data to project the number of days on feed that will maximize profitability. The KSU sorting system was applied, 3 to 4 mo before slaughter, on 4101 yearling steers at two large feedlots located in southern Alberta. In Feedlot 1, steers averaging 408.7 kg (SD = 45.2 kg) were randomly assigned to two treatment groups: sorted by weight (control; n = 856) and sorted by the KSU sorting system (n = 849). In Feedlot 2, steers averaging 494.4 kg (SD = 42.3 kg) were randomly assigned to two treatment groups: not sorted (control; n = 798) and sorted by the KSU sorting system (n = 1598). Whole pens were marketed when the majority of steers in the pen approached the carcass weight and grade characteristics required for optimal return. The KSU sorted steers gained 0.12 kg d−1 faster at Feedlot 1 (P = 0.043) and 0.05 kg d−1 faster at Feedlot 2 (P = 0.036) than control steers. Feed intake, feed efficiency, death loss, warm carcass weight, backfat thickness, l. dorsi area, marbling score and lean meat yield were similar between sorting systems regardless of feedlot. The KSU sorting system reduced dark cutting (B4) carcasses to zero (0.0% KSU vs. 1.3% Control; P = 0.005) and increased AAA quality grade carcasses by 40.8% (31.4% KSU vs. 22.3% Control; P = 0.001) in Feedlot 1. In Feedlot 2, the KSU sorting system reduced over-fat carcasses (Y3) by 47.4% (10.2% KSU vs. 19.4% Control; P = 0.001) and increased AA carcasses by 14.7% (52.3% KSU vs. 45.6% Control; P = 0.003). These changes resulted in the KSU sorted steers being more profitable than control steers by $27.67 head−1 in Feedlot 1 and $15.22 head−1 in Feedlot 2. The increased net return was primarily due to improved weight gains and a more desirable distribution of carcass yield and quality grades. Key words: Ultrasound, carcass uniformity, steers
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Lu, Ning, Jorge Estrada, Andrea Hanson, Carine M. Vier, Jose A. Soto, Gustavo Silva, Beau Peterson, et al. "274 Effects of Feeding Levels in Early Gestation on PIC Camborough Sows and Litter Performance." Journal of Animal Science 100, Supplement_3 (September 21, 2022): 119–20. http://dx.doi.org/10.1093/jas/skac247.229.
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Abstract Our objective was to determine the effects of increasing feeding levels for PIC Camborough sows during early gestation on sow and litter performance. A total of 636 sows (PIC Camborough) were randomly assigned at weaning to 1 of 4 treatments that were balanced for weight and caliper scores within parity categories. Treatments consisted of feeding sows with daily feed allowances to meet 85, 115, 145, or 175% of the NRC (2012) maintenance metabolizable energy (MEm) requirement calculated as MEm, kcal/d = 100 × (body weight, kg)0.75. A common corn-soybean meal-distillers dried grains with solubles-based diet with 3,092 kcal of ME/kg and 0.64% standardized ileal digestible lysine was used. Treatments were applied from d 6 to 35 of gestation, after which sows were moved to gestation pens and fed according to body condition through an electronic sow feeder until moved to the farrowing room. Sow was the experimental unit and data were analyzed using generalized linear mixed models with the lmer and glmer functions of R. On average, females were ideal condition at weaning across treatment as determined by the caliper scores. Average feed allowances were 1.6, 2.1, 2.6, and 3.2 kg/day for the 85, 115, 145, and 175% treatments, respectively. Increasing feed allowances reduced (linear, P< 0.05) body weight loss (-13.8, -10.3, -4.7 and -0.5 kg, respectively) and increased caliper score gain (-0.43, -0.03, 0.64, 0.76 units, respectively) from weaning to d 35 of gestation. There was no evidence for treatment effects on farrowing rate, total born, stillborn rate, average litter weight, piglet throughput, or subsequent reproductive performance. In summary, increasing feed allowances to meet 85 to 175% of the MEm requirements during early gestation on Camborough sows resulted in a reduction in body weight loss and an improvement in caliper gain until d 35 of gestation without evidence of impact in reproductive performance.
Dissertations / Theses on the topic "Loss-in-Weight Feeder"
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Dias, Beatriz Filipa Cabral. "Optimization of Loss in Weight Feeding of Pharmaceutical Powders to Enable Continuous Direct Compression." Master's thesis, 2022. http://hdl.handle.net/10362/132665.
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Over the last years the pharmaceutical industry has been gradually starting to adhere to the continuous production instead of the traditional batch production.
For the production of tablets through continuous direct compression (CDC) it is essential to ensure the control of all the equipment involved in the process, with special attention to the Loss-in-Weight (LIW) Feeders. This is due to the fact that even if there are small oscillations in the initial phase of the process, these will have big repercussions on the quality of the final product, making the drug getting out of the specification.
This work explore different materials with the goal of creating a methodology for the selection of the components (the tools) to be assembled on the feeder in order to optimise the process. Furthermore, the minimum and maximum limits of the feeders were tested to determine a stable range of operation for each analysed material.
Afterwards, a database with the different properties of the materials was developed with the goal of relating these properties with the components that would be necessary to integrate on the feeder and optimise its performance. To simplify the identification of similarities between the analysed materials, a principal component analysis (PCA) model was developed.
Following this, some alternatives to reduce the time and costs of the production process were identified. Thus, the development of partial least squares (PLS) models was essential to predict the feed factor (FF) values.
Lastly, the impact that the usage of the feeder had over the materials was analysed in order to find out if this equipment would cause any alterations in the properties of the materials to be used in the formulation.Nos últimos anos a indústria farmacêutica tem vindo gradualmente a aderir à produção em contínuo em detrimento da tradicional produção em batch. Para a produção de comprimidos através de continuous direct compression (CDC) é essencial garantir o controlo de todos os equipamentos do processo, com especial atenção para os Loss-in-Weight (LIW) Feeders. Tal deve-se ao facto de que mesmo que sejam pequenas as oscilações na fase inicial do processo, estas terão grandes repercussões na qualidade do produto final, dando origem a um medicamento fora de especificação. Durante este trabalho procurou-se testar diversos materiais com o objetivo de criar uma metodologia para a seleção dos componentes (peças) a serem integrados no feeder de forma a otimizar o seu funcionamento. Para além disso, foram também testados os limites mínimos e máximos de funcionamento do feeder, de forma a se determinar um intervalo de operação estável para cada material analisado. Posteriormente, foi desenvolvida uma base de dados com as diversas propriedades dos materiais, cujo objetivo seria relacionar essas propriedades aos componentes que viriam a ser necessários integrar no feeder de forma a otimizar o seu funcionamento. Com o objetivo de facilitar a deteção das semelhanças entre os materiais analisados foi desenvolvido um modelo de principal component analysis (PCA). Em seguida, foram identificadas alternativas para reduzir o tempo e o custo dos processos de produção, para o que foi essencial o desenvolvimento de modelos de partial least squares (PLS) para prever os valores dos feed factor (FF). Por último, foi analisado o impacto que a utilização do feeder teve sobre os materiais, no sentido de se averiguar se a utilização deste equipamento provocaria alterações nas propriedades dos materiais a serem utilizados na formulação.
Books on the topic "Loss-in-Weight Feeder"
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McCleary, Larry. Feed your brain, lose your belly: A brain surgeon reveals the weight-loss secrets of the brain-belly connection. 2nd ed. Austin, Tex: Greenleaf Book Group Press, 2011.
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McCleary, Larry. Feed Your Brain, Lose Your Belly: A Brain Surgeon Reveals the Weight-Loss Secrets of the Brain-Belly Connection. Greenleaf Book Group, 2011.
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Feed Your Brain Lose Your Belly. Teocalli, 2010.
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McCleary, Larry. Feed Your Brain, Lose Your Belly: Experience Dynamic Weight Loss with the Brain-Belly Connection. Teocalli, LLC, 2021.
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McCleary, Larry. Feed Your Brain, Lose Your Belly: A Brain Surgeon Reveals the Weight-Loss Secrets of the Brain-Belly Connection. Teocalli, LLC, 2021.
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McCleary, Larry. Feed Your Brain, Lose Your Belly: A Brain Surgeon Reveals the Weight-Loss Secrets of the Brain-Belly Connection. Teocalli, LLC, 2021.
Find full textBook chapters on the topic "Loss-in-Weight Feeder"
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Bolkhovskaya, Olesya, Alexander Maltsev, Valentin Seleznev, and Ilya Bolotin. "Cost-Efficient RAA Technology for Development of the High-Gain Steerable Antennas for mmWave Communications." In Machine Learning and Artificial Intelligence. IOS Press, 2020. http://dx.doi.org/10.3233/faia200800.
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For the future millimeter wave wireless systems the high gain steerable antennas are the key technology to overcome large path loss and support users’ mobility and reconfigurable backhauling. This paper introduces a specially designed reflect-array antenna (RAA), integrating single phased antenna array (PAA) module (as a feed source) and flat reflecting surface. The RAA provides high antenna gain by focusing the beam in vertical plane, but, at the same time, supporting beamsteering capability in the horizontal plane. The RAA technology allows creation of the very larger aperture antennas with simplified light-weight design. Two RAA prototypes with different feed source mounting demonstrated reliable multi-gigabit IEEE 802.11ad link 2.3–4.62 Gbps at distances 100–150m. These properties of the RAAs make them suitable for both millimeter-wave mobile access and reconfigurable backhauling applications.
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Faji Dida, Mulisa. "Strategies for Goat Feeding and Management during Drought." In Goat Science - Environment, Health and Economy [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.101161.
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Nowadays, climate change is becoming a serious problem threatening livestock production by affecting their environment, health, and feed sources. Many parts of the tropical countries, particularly the pastoralist area, experience extended periods of drought, leading to shortages of feed and water. During these periods, goats are incapable of meeting their nutrient requirement for maintenance and will begin to lose weight as body reserves are depleted, causing economic loss to the goats. In the extremely long dry season, animals die, with the youngest, weakest, and oldest dying first. As a result, drought management entails balancing pasture and water supply against forage and water demand. In most cases, no single strategy will suffice to address this issue. Each situation would need a different set of strategies Therefore, this chapter will come with some common options/ strategies that can be avail feed shortage during drought. Those strategies are purchase of feed from surplus location, adjustment of animal management, policy intervention, destocking, adjusting grazing strategies during drought, supplementation, maintenance feeding, reallocation of a given amount of feed in the herd, early weaning and creep feeding, lowering stocking rate, water sources and supplies, development and effective utilization of feed resources, and creation of feed banks.
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Alagawany, Mahmoud, Rana Muhammad Bilal, Fiza Batool, Youssef A. Attia, Mohamed E. Abd El-Hack, Sameh A. Abdelnour, Mayada R. Farag, Ayman A. Swelum, and Mahmoud Madkour. "Use of Psyllium Husk (Plantago ovata) in Poultry Feeding and Possible Application in Organic Production." In Antibiotic Alternatives in Poultry and Fish Feed, 111–23. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815049015122010011.
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Herbs or medicinal plants have gained significant attention due to their bioactive compounds that could act as antioxidants, anti-inflammatory, antimicrobial, anticancer agents, etc. Psyllium husk (Plantago ovata) is an Indian native herb. The water-loving (hydrophilic) mucilloid and water-soluble fiber derived from Plantago ovata have been used in traditional Indian Ayurvedic medicine as a crucial remedial mediator of constipation. Psyllium is a rich source of fiber and has many other remedial properties, including lowering the level of cholesterol, raising energy, relaxing inflammation, serving as an antidiarrhoeal, antidiabetic, laxative, and also used in hemorrhoid therapy, and as weight loss agent. The blood serum cholesterol-lowering property of the psyllium husk had drawn the researchers' main focus; thus, Psyllium is thought to be a plausible herbal agent helpful in treating hyperlipidemia. In various animal models, cholesterol levels are reduced by binding Psyllium husk with bile acids in the intestinal, thereby lowering its absorption rate. Screening literature has demonstrated that Psyllium husk could be utilized as an antidiarrheal mediator to cope with the diarrheal symptoms associated with poultry farming disorders. Additionally, Psyllium may also benefit various poultry species' production and growth traits. The present chapter explored Psyllium's potential responsibility for coping the hypercholesterolemia and the uses of psyllium husk as a safe feed additive in poultry farming for organic production and lowering cholesterol in meat and for production of functional foods.
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Kozdruń, Wojciech, Jowita Samanta Niczyporuk, and Natalia Styś-Fijoł. "Marek’s Disease Is a Threat for Large Scale Poultry Production." In Veterinary Medicine and Science. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98939.
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Marek’s disease (MD) is one of the widespread infectious diseases that causes huge losses in large-scale poultry production. This is due to weight loss, poorer feed conversion and an increased number of deaths among infected birds. The etiological agent is a Marek’s disease virus (MDV) belonging to the Herpesviridae family. It is mainly described in poultry, however, it is also found in geese. There are three MDV serotypes, and four patotypes within serotype 1. Currently, Marek’s disease is very rare in its classical form. There are non-specific clinical symptoms, and anatomopathological changes are mainly observed in the liver, spleen and the reproductive system. This may be due to the evolution in the pathogenicity of MDV field strains over the past several decades. The presence of MDV and number of molecular diagnostic tests based on the detection of viral nucleic acids and viral proteins is already found in birds that have several weeks old. Laboratory diagnostics are based mainly on molecular biology (mainly PCR) methods. The only relatively effective method instead of biosecurity measures, of preventing MD is prophylactic vaccination of 1-day-old chickens or in ovo vaccination. Nevertheless, Marek’s disease is still recorded in poultry flocks around the world, with estimated losses reaching several million dollars.
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Babinszky, László, Csaba Szabó, and Márta Horváth. "Perspective Chapter: Using Feed Additives to Eliminate Harmful Effects of Heat Stress in Broiler Nutrition." In Advanced Studies in the 21st Century Animal Nutrition. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.101030.
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Global warming is one of the major challenges for mankind, with animal breeding one of the most affected sectors in the agricultural industry. High ambient temperatures negatively affect all domestic animals. While it is true that pork and dairy production suffer the consequences of heat waves, it is actually the poultry industry which is hit the hardest by the heat stress poultry must endure due to hotter weather. Consequently, we have a fundamental interest in reducing and/or eliminating the negative effects of climate change, i.e. prolonged high ambient temperatures. The aim of this chapter is to present the adverse effects of heat stress on energy metabolism, anti- and pro-oxidant capacity and production in birds. A further goal is to show how various feed additives (e.g. vitamin A, C and E, selenium, zinc, betaine, plant extract, and probiotics) can reduce the negative effects of heat stress. Based on the large number of recent scientific findings, the following conclusions were drawn: Using fat in the diet (up to 5%) can reduce heat production in livestock. Vitamins (e.g. A, E and C) are capable of reacting with free radicals. Vitamin E and Vitamin C, Zn, and Se supplementation improved antioxidant parameters. Antioxidant potential of vitamins and micro minerals is more efficient in combination under heat stress in poultry nutrition. Plant extracts (e.g. oregano) could decrease the negative effects of heat stress on antioxidant enzyme activity due to its antioxidant constituents. Betaine reduces heat production in animals at high ambient temperatures. While acute heat stress induces a drop in feed intake, with the resulting increased nutrient demand leading to weight loss, if heat stress is prolonged, adaptation will occur. Probiotics and vitamins (C and E) seem to be the most effective means to reduce the negative effects of heat stress.
Conference papers on the topic "Loss-in-Weight Feeder"
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Koncz, Dorottya. "Reports of illegal food supplements for weight loss in the European Rapid Alert System for Food and Feed (RASFF)." In 2nd Symposium of Young Researchers on Pharmacognosy. Szeged: Department of Pharmacognosy, University of Szeged, Faculty of Pharmacy, 2021. http://dx.doi.org/10.14232/syrpharmacognosy.2021.a12.
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Verbrugghe, Adronie, and Alexandra Rankovic. "Dietary choline in feline nutrition and its role in obesity prevention and liver health." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/gyun6061.
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In North America, 60% of cats is estimated to be overweight or obese, predisposing cats to obesity-related health consequences, which reduce quality and quantity of life. Weight loss is recommended, yet current protocols are often unsuccessful. Moreover, drastic energy restriction can put overweight and obese cats at risk of developing feline hepatic lipidosis which can be fatal if left untreated.Choline, an essential nutrient, can be found naturally in organ meats, eggs, soybean and wheat germ. Commercial pet foods contain a supplemental source of choline to meet the recommendations set by the Association of American Feed Control Officials. For cats, 2400 mg/kg diet on a dry matter basis or 600 mg/1000 kcal metabolizable energy is recommended for growth and adult maintenance. Choline is a methyl group donor involved in multiple metabolic pathways and plays an important role in fat metabolism and mobilization, particularly in the liver. Choline is a precursor for phosphatidylcholine, an essential component of very-low-density lipoproteins, crucial for exporting triglycerides and cholesterol out of the liver and into circulation. Research in many animal species, including cats, has found that a diet deficient in choline results in hepatic fat accumulation. Similarly in rats, high-fat diet-induced fatty livers were reversed with choline. Choline supplementation studies in the animal nutrition field have largely focused on growth and weight gain in livestock. This research uncovered decreased fat deposition and increased lean carcass composition with supplementation of choline or its derivative betaine.
This session will summarize recent choline research in cats. The findings suggest that supplementing choline, above an animal’s recommended allowance, may help to reduce body fat gain in growing kittens after neutering, and help mobilize fats from the liver in overweight and obese cats, proposing a novel nutritional strategy for obesity prevention and liver health in domestic cats.
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Deshpande, Ashish, Shu Yang, Dave Puleo, David Pienkowski, Oscar Dillon, Jose Outeiro, and I. S. Jawahir. "Minimized Wear and Debris Generation Through Optimized Machining of Co-Cr-Mo Alloys for Use in Metal-on-Metal Hip Implants." In ASME 2012 International Manufacturing Science and Engineering Conference collocated with the 40th North American Manufacturing Research Conference and in participation with the International Conference on Tribology Materials and Processing. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/msec2012-7260.
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More than 380,000 hips are replaced with total joint prostheses each year in the U.S. Wear debris generated by metal-on-metal implant designs is of concern due to potential adverse biological effects arising from chronic exposure of human tissue to the wear debris. This paper presents a new methodology for optimizing the wear performance of prosthesis made of Co-Cr-Mo alloys by varying tool edge geometry and machining conditions to alter the wear behavior of this alloy, while also controlling the residual stresses induced during the machining process. The machining process causes inhomogeneous inelastic deformations near the surface layer of machined parts which create residual stresses in the surface of machined components. Residual stresses in the machined surface and the subsurface are affected by cutting tool material, tool geometry, workpiece, tool-work interface conditions, and the cutting parameters such as feed rate, depth of cut and cutting speed. In the current work, residual stresses were measured using X-ray diffraction technique (XRD). The surface residual stresses in two directions (radial and hoop) were measured on the machined pins after machining with different machining conditions, but prior to the wear test. Wear behavior of Co-Cr-Mo alloy pin specimens, produced from machining with varying tool edge geometry and machining conditions, was studied using a custom-made biaxial motion pin-on-disc tribological testing system in which the pin specimen is immersed in a simulated bio-fluid environment. Wear-induced weight loss (± 10 μg) and changes in surface roughness (± 0.001 μm) were obtained at 100,000 cycle intervals upto 500,000 cycles. Metallographic analysis was performed on the machined pin specimens to analyze the microstructure and microhardness before and after testing. The rate of wear for the specimens was lowest for those pins where the change of the subsurface microhardness was small due to prevention of additional steady state wear after the initial run-in wear in the wear tester. A combination or response surface methodology and genetic algorithm (GA) was used in to optimize the various machining parameters for minimized wear generation. The optimal combination of the four machining parameters (feed 0.18mm/rev, nose radius 0.6 mm, cutting speed 27.6 m/min and depth of cut 0.38) produced the largest compressive residual stresses on the surface and subsurface of the implants thereby reducing the wear/debris generation by about fifty percent.
Reports on the topic "Loss-in-Weight Feeder"
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Cahaner, Avigdor, Sacit F. Bilgili, Orna Halevy, Roger J. Lien, and Kellye S. Joiner. effects of enhanced hypertrophy, reduced oxygen supply and heat load on breast meat yield and quality in broilers. United States Department of Agriculture, November 2014. http://dx.doi.org/10.32747/2014.7699855.bard.
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Original objectivesThe objectives of this project were to evaluate the growth performance, meat yield and quality attributes of broiler strains widely differing in their genetic potential under normal temperature vs. warm temperature (short and long-term) conditions. Strain differences in breast muscle accretion rate, metabolic responses under heat load and, gross and histopathological changes in breast muscle under thermal load was also to be characterized. BackgroundTremendous genetic progress has been made in broiler chicken growth rate and meat yield since the 1950s. Higher growth rate is driven by higher rates of feed intake and metabolism, resulting in elevated internal heat production. Hot rearing conditions negatively affect broiler growth by hindering dissipation of heat and may lead to a lethal elevation in body temperature. To avoid heat-induced mortality, broilers reduce feed intake, leading to depressed growth rate, lower weight gain, reduce breast meat yield and quality. Thus, the genetic potential of contemporary commercial broilers (CCB) is not fully expressed under hot conditions. Major conclusions, solutions, and achievementsResearch conducted in Israel focused on three broiler strains – CCB, Featherless, Feathered sibs (i.e., sharing similar genetic background). Complimentary research trials conducted at Auburn utilized CCB (Cobb 500, Cobb 700, Ross 308, Ross 708), contrasting their performance to slow growing strains. Warm rearing conditions consistently reduced feed intake, growth rate, feed efficiency, body weight uniformity and breast muscle yield, especially pronounced with CCB and magnified with age. Breast meat quality was also negatively affected, as measured by higher drip loss and paler meat color. Exposure to continuous or short-term heat stress induced respiratory alkalosis. Breast muscle histomorphometrics confirmed enhanced myofiber hypertrophy in CCB. Featherless broilers exhibited a significant increase in blood-vessel density under warm conditions. Rapid growth and muscle accretion rate was correlated to various myopathies (white striping, woody and necrotic) as well as to increases in plasma creatinekinase levels. Whether the trigger(s) of muscle damage is loss of cellular membrane integrity due to oxidative damage or tissue lactate accumulation, or to loss of inter-compartmental cation homeostasis is yet to be determined. Based on genome-wide single-nucleotide polymorphism array genotyping, identification of the gene with the recessive mutation Scaleless (sc) facilitated the development a dCAPS assay to discriminate between sc carrier (sc/+) and non-carrier (+/+) individuals. ImplicationsThis project confirmed that featherless broiler strains grow efficiently with high yield and quality of breast meat, even under warm rearing conditions that significantly depress the overall performance of CCB. Therefore, broiler meat production in hot regions and climates can be substantially improved by introducing the featherless gene into contemporary commercial broiler stocks. This approach has become more feasible with the development of dCAPS assay. A novel modification of the PCR protocol (using whole blood samples instead of extracted DNA) may contribute to the efficient development of commercial featherless broiler strains. Such strains will allow expansion of the broiler meat production in developing countries in warm climates, where energy intensive environmental control of rearing facilities are not economical and easily achievable.
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Yahav, Shlomo, John McMurtry, and Isaac Plavnik. Thermotolerance Acquisition in Broiler Chickens by Temperature Conditioning Early in Life. United States Department of Agriculture, 1998. http://dx.doi.org/10.32747/1998.7580676.bard.
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The research on thermotolerance acquisition in broiler chickens by temperature conditioning early in life was focused on the following objectives: a. To determine the optimal timing and temperature for inducing the thermotolerance, conditioning processes and to define its duration during the first week of life in the broiler chick. b. To investigate the response of skeletal muscle tissue and the gastrointestinal tract to thermal conditioning. This objective was added during the research, to understand the mechanisms related to compensatory growth. c. To evaluate the effect of early thermo conditioning on thermoregulation (heat production and heat dissipation) during 3 phases: (1) conditioning, (2) compensatory growth, (3) heat challenge. d. To investigate how induction of improved thermotolerance impacts on metabolic fuel and the hormones regulating growth and metabolism. Recent decades have seen significant development in the genetic selection of the meat-type fowl (i.e., broiler chickens); leading to rapid growth and increased feed efficiency, providing the poultry industry with heavy chickens in relatively short growth periods. Such development necessitates parallel increases in the size of visceral systems such as the cardiovascular and the respiratory ones. However, inferior development of such major systems has led to a relatively low capability to balance energy expenditure under extreme conditions. Thus, acute exposure of chickens to extreme conditions (i.e., heat spells) has resulted in major economic losses. Birds are homeotherms, and as such, they are able to maintain their body temperature within a narrow range. To sustain thermal tolerance and avoid the deleterious consequences of thermal stresses, a direct response is elicited: the rapid thermal shock response - thermal conditioning. This technique of temperature conditioning takes advantage of the immaturity of the temperature regulation mechanism in young chicks during their first week of life. Development of this mechanism involves sympathetic neural activity, integration of thermal infom1ation in the hypothalamus, and buildup of the body-to-brain temperature difference, so that the potential for thermotolerance can be incorporated into the developing thermoregulation mechanisms. Thermal conditioning is a unique management tool, which most likely involves hypothalamic them1oregulatory threshold changes that enable chickens, within certain limits, to cope with acute exposure to unexpected hot spells. Short-tem1 exposure to heat stress during the first week of life (37.5+1°C; 70-80% rh; for 24 h at 3 days of age) resulted in growth retardation followed immediately by compensatory growth" which resulted in complete compensation for the loss of weight gain, so that the conditioned chickens achieved higher body weight than that of the controls at 42 days of age. The compensatory growth was partially explained by its dramatic positive effect on the proliferation of muscle satellite cells which are necessary for further muscle hypertrophy. By its significant effect of the morphology and functioning of the gastrointestinal tract during and after using thermal conditioning. The significant effect of thermal conditioning on the chicken thermoregulation was found to be associated with a reduction in heat production and evaporative heat loss, and with an increase in sensible heat loss. It was further accompanied by changes in hormones regulating growth and metabolism These physiological responses may result from possible alterations in PO/AH gene expression patterns (14-3-3e), suggesting a more efficient mechanism to cope with heat stress. Understanding the physiological mechanisms behind thermal conditioning step us forward to elucidate the molecular mechanism behind the PO/AH response, and response of other major organs. The thermal conditioning technique is used now in many countries including Israel, South Korea, Australia, France" Ecuador, China and some places in the USA. The improvement in growth perfom1ance (50-190 g/chicken) and thermotolerance as a result of postnatal thermal conditioning, may initiate a dramatic improvement in the economy of broiler's production.
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Yahav, Shlomo, John Brake, and Orna Halevy. Pre-natal Epigenetic Adaptation to Improve Thermotolerance Acquisition and Performance of Fast-growing Meat-type Chickens. United States Department of Agriculture, September 2009. http://dx.doi.org/10.32747/2009.7592120.bard.
Full textAbstract:
: The necessity to improve broiler thermotolerance and performance led to the following hypothesis: (a) thethermoregulatory-response threshold for heat production can be altered by thermal manipulation (TM) during incubation so as to improve the acquisition of thermotolerance in the post-hatch broiler;and (b) TM during embryogenesis will improve myoblast proliferation during the embryonic and post-hatch periods with subsequent enhanced muscle growth and meat production. The original objectives of this study were as follow: 1. to assess the timing, temperature, duration, and turning frequency required for optimal TM during embryogenesis; 2. to evaluate the effect of TM during embryogenesis on thermoregulation (heat production and heat dissipation) during four phases: (1) embryogenesis, (2) at hatch, (3) during growth, and (4) during heat challenge near marketing age; 3. to investigate the stimulatory effect of thermotolerance on hormones that regulate thermogenesis and stress (T₄, T₃, corticosterone, glucagon); 4. to determine the effect of TM on performance (BW gain, feed intake, feed efficiency, carcass yield, breast muscle yield) of broiler chickens; and 5. to study the effect of TM during embryogenesis on skeletal muscle growth, including myoblast proliferation and fiber development, in the embryo and post-hatch chicks.This study has achieved all the original objectives. Only the plasma glucagon concentration (objective 3) was not measured as a result of technical obstacles. Background to the topic: Rapid growth rate has presented broiler chickens with seriousdifficulties when called upon to efficiently thermoregulate in hot environmental conditions. Being homeotherms, birds are able to maintain their body temperature (Tb) within a narrow range. An increase in Tb above the regulated range, as a result of exposure to environmental conditions and/or excessive metabolic heat production that often characterize broiler chickens, may lead to a potentially lethal cascade of irreversible thermoregulatory events. Exposure to temperature fluctuations during the perinatal period has been shown to lead to epigenetic temperature adaptation. The mechanism for this adaptation was based on the assumption that environmental factors, especially ambient temperature, have a strong influence on the determination of the “set-point” for physiological control systems during “critical developmental phases.” In order to sustain or even improve broiler performance, TM during the period of embryogenesis when satellite cell population normally expand should increase absolute pectoralis muscle weight in broilers post-hatch. Major conclusions: Intermittent TM (39.5°C for 12 h/day) during embryogenesis when the thyroid and adrenal axis was developing and maturing (E7 to E16 inclusive) had a long lasting thermoregulatory effect that improved thermotolerance of broiler chickens exposed to acute thermal stress at market age by lowering their functional Tb set point, thus lowering metabolic rate at hatch, improving sensible heat loss, and significantly decreasing the level of stress. Increased machine ventilation rate was required during TM so as to supply the oxygen required for the periods of increased embryonic development. Enhancing embryonic development was found to be accomplished by a combination of pre-incubation heating of embryos for 12 h at 30°C, followed by increasing incubation temperature to 38°C during the first 3 days of incubation. It was further facilitated by increasing turning frequency of the eggs to 48 or 96 times daily. TM during critical phases of muscle development in the late-term chick embryo (E16 to E18) for 3 or 6 hours (39.5°C) had an immediate stimulatory effect on myoblast proliferation that lasted for up to two weeks post-hatch; this was followed by increased hypertrophy at later ages. The various incubation temperatures and TM durations focused on the fine-tuning of muscle development and growth processes during late-term embryogenesis as well as in post-hatch chickens.