2,280 research outputs found

    Understanding the Impact of Meteorological Spatiotemporal Variability on Distant Focusing Overpressure Risk

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    Since the 1950s, the amplification of blast energy from explosions has been understood to be a significant hazard to public safety at launch ranges. Historically, the risk assessment of the Distant Focusing Overpressure (DFO) hazard started with a single temperature and wind profile (e.g., a radiosonde launch) as input to acoustic 1-D ray tracing models. By analyzing rays propagation and performing ray tracing, population centers under high DFO risk can be identified. Although this method is useful, less is known about how the blast waves can be focused when the spatiotemporal variability of the input profiles are considered. In summary, this work aims to consider how realistic atmospheric boundary layer variability (e.g., turbulence, land-surface contrasts) may affect blast waves propagation and focusing and, as a result, DFO risk assessment results

    Issued as a Documentation Report on an Investigation of Field-Made Joints in Prestressed Reinforced Concrete Highway Girder Bridges, Project IHR-303, Phase 2

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    A prototype bridge girder was designed, built, and tested. The 250 ft long two-span girder was made of 3 precast segments about 88, 74, and 88 ft in length. The segments were supported on 3 final and 2 temporary supports. The joints were of cast-in-place concrete, as was the composite deck. After the site-cast concrete was cured, the structure was post-tensioned to establish continuity and the temporary supports were removed. The two longer segments were pretensioned to resist the girder and deck dead loads, while the shorter segment was reinforced with deformed bars for the same loads. The structure was subjected to a series of loadings, during which deflections, reactions, and concrete strains were measured. The loads approximated AASHTO HS-20 vehicles. The first 4 tests ,were to service loads, with total applied loads of 73.6 kips. The structure remained elastic and crack free during these tests. Two tests were to the design ultimate load, 198.7 kips. A load of 328.2 kips was applied in the final test without causing failure. The final loading was applied to produce maximum shear in one splice, and a shear failure, complicated by large flexural deformations, appeared to be developing when the test ended. The final test produced a maximum deflection of 10.8 in., and a residual of about 1.0 in. The joint details used in the prototype structure were adequate, and the presence of the, joint had no influence on the behavior of the structure until extremely large overloads were reached.State of Illinois Department of TransportationU.S. Department of Transportation. Federal Highway AdministrationProject IHR-30

    Effect of seasonality on quality and fertility of cryopreserved New Zealand white rabbit semen under Egyptian conditions

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    [EN] The present study was designed to investigate the effect of seasonality on the quality and fertility of cryopreserved New Zealand white (NZW) rabbit semen under Egyptian conditions. Semen was collected from fifteen mature rabbit bucks during winter, spring, summer and autumn seasons, diluted in INRA-82 extender and cryopreserved in liquid nitrogen. Following the freezing/thawing process, semen samples were evaluated for semen quality parameters. We also investigated whether seasonality could affect postthaw fertility. The results showed that semen collected and processed during winter, autumn, and spring significantly improved (P<0.05) sperm motility (56.33, 54.12 and 54.00%, respectively), live sperm (59.24, 58.34 and 57.01%, respectively), functional membrane integrity hypo osmotic swelling test (67.34, 64.59 and 64.31%, respectively), acrosome intactness (79.25, 77.45 and 76.72%, respectively) and sperm with non-fragmented DNA (75.66, 74.02% and 72.53%, respectively) in comparison with semen collected and processed in summer season (30.24, 33.26, 42.51, 51.20 and 40.22%, respectively). The fertility results revealed that conception and kindling rates were significantly higher (P<0.05) when semen samples were collected and processed in winter (80.00 and 76.00%, respectively) in comparison with those collected and processed in autumn (74.00 and 70.00%, respectively), spring (70.00 and 64.00%, respectively) and summer (30.00 and 20.00%, respectively). In summary, our results show that the quality and fertility of cryopreserved NZW rabbit buck semen depends on the season during which the semen is collected and processed. Moreover, for the best fertility results in doe insemination, semen collected and processed (cryopreserved) in winter season should be used.Fadl, A. (2020). Effect of seasonality on quality and fertility of cryopreserved New Zealand white rabbit semen under Egyptian conditions. World Rabbit Science. 28(3):123-128. https://doi.org/10.4995/wrs.2020.13627OJS123128283Abdel-Samee A.M. 1987. The role of cortisol in improving productivity of heat-stressed farm animals with different techniques. PhD. Thesis, Fac, Agric, Zagazig University, Zagazig, Egypt.Ahmed N.A., Barkawi A.H., Azamel A.A., Morsy A.S. 2006. Semen characteristics of rabbit bucks as affected by vitamin C injection under different ambient temperatures in Egypt. Egypt. J. Rabbit Sci., 16: 47-59.Di Iorio M. 2014. Cryopreservation of rabbit semen: effectiveness of different permeable and non-permeable cryoprotectants on post-thaw sperm quality and reproductive performances. Thesis, university of Molise, Italy.Di Iorio M., Colonna M.A., Miranda M., Principe P., Schiavitto M., Cerolini S. 2018. Initial cooling time before freezing affects post-thaw quality and reproductive performance of rabbit semen. Anim. Sci. J., 89: 1240-1244. https://doi.org/10.1111/asj.13046De Lamirande E., O'Flaherty C. 2008. Sperm activation: role of reactive oxygen species and kinases. Biochim. Biophys. Acta., 1784: 106-115. https://doi.org/10.1016/j.bbapap.2007.08.024El-Sayed A., Iraqi M.M., Elwan K., Team F.E.I., El-Hanafy A. 2016. Seasonal Variation in Libido and Semen Characteristics of Sinai Gabali Rabbits. Arab J. Nuclear Sci. Appl., 94: 160-166.Evans G., Maxwell W.C. 1987. Salamons' artificial insemination of sheep and goats (No. Ed. 2). Butterworths.Fadl-Aya M., Ghallab A.M., Abou-Ahmed M.M. 2019. Quality assessment of cryopreserved New Zealand white rabbit spermatozoa in INRA-82 extender containing different cryoprotectants. World Rabbit Sci., 27: 77-83. https://doi.org/10.4995/wrs.2019.10892Finzi A., Morera P., Kuzminsky G. 1995. Sperm abnormalities as possible indicators of rabbit chronic heat stress. World Rabbit Sci., 3: 157-161. https://doi.org/10.4995/wrs.1995.256Ghallab A.M., Shahat A.M., Fadl A.M., Ayoub M.M., Moawad A.R. 2017. Impact of supplementation of semen extender with antioxidants on the quality of chilled or cryopreserved Arabian stallion spermatozoa. Cryobiology, 79: 14-20. https://doi.org/10.1016/j.cryobiol.2017.10.001Haines G., Marples B., Daniel P., Morris I. 1998. DNA damage in human and mouse spermatozoa after in vitro-irradiation assessed by the comet assay. Reprod. Toxicol., 444: 79-93. https://doi.org/10.1007/978-1-4899-0089-0_10Khalil H.A., Kishik W.H., Rabaa A., Tharwat, Yaseen M.A., Ayoub M.A. 2015. Physiological Body Reactions and Semen Characters of Rabbit Bucks as Affected by Breed and Vitamin C Supplementation under Egyptian Summer Conditions. Journal of Animal, Poultry & Fish Production., 4: 17-23. https://doi.org/10.21608/japfp.2015.7425Marai I.F.M., Ayyat M.S., Gabr H.A., Abd El-Monem U.M. 1996. Effect of summer heat stress and its amelioration on production performance of New Zealand White adult female and male rabbits, under Egyptian conditions. In Proc.: 6th world rabbit congress, 9-12 July 1996, Toulouse, France, vol. 2, pp. 197-208.Marai I.F.M., Ayyat M.S., Abd-El-Monem, U.M. 2001. Growth performance and reproductive traits at first parity of New Zealand White female rabbits as affected by heat stress and its alleviation under Egyptian conditions. Tropic. Anim. Health Prod., 33: 1-12. https://doi.org/10.1023/A:1012772311177Marai I.F.M., Habeed A.A.M., Gad A.E. 2002. Rabbits productive, reproductive and physiological performance traits as affected by heat stress: a review. Livest. Prod. Sci., 78: 71-90. https://doi.org/10.1016/S0301-6226(02)00091-XMocé E., Vicente J.S. 2009. Rabbit sperm cryopreservation: a review. Anim. Reprod. Sci., 110: 1-24. https://doi.org/10.1016/j.anireprosci.2008.08.015Mousa-Balabel T.M., El-Sheikh R.A., Moustafa E.M. 2017. New strategies for controlling heat stress in New Zealand White (NZW) rabbits in Egypt. Life Sci. J., 14: 64-70.Okab, A.B., El-Banna S.G., Koriem A.A. 2008. Influence of environmental temperatures on some physiological and biochemical parameters of male New-Zealand rabbits. Slovak Journal of Animal Science., 41: 12-19.Roca J., Martínez S., Orengo J., Parrilla I., Vázquez J.M., Martínez E.A. 2005. Influence of constant long days on ejaculate parameters of rabbits reared under natural environment conditions of the Mediterranean area. Livest. Prod. Sci., 94: 169-177. https://doi.org/10.1016/j.livprodsci.2004.10.011Saacke R.G. 1998. AI fertility: Are we getting the job done? In Proc. 17th Nat. Assoc. Anim. Breeders Tech. Conf. on AI and Reprod. Milwaukee, WI. pp 6-13.Safaa H.M., Emarah M.E., Saleh N.F.A. 2008. Seasonal effects on semen quality in Black Baladi and New Zealand White rabbit bucks. World Rabbit Sci., 16: 13-20. https://doi.org/10.4995/wrs.2008.640Seleem T.S.T., Fayek H.M., El-Kholy K.H., Afifi S.M. 2007. Rabbit productivity and reproductivity as influenced by prebiotics in drinking water. In Proc: 4th World Poultry Conf. 27- 30 March, Sharm El- Sheikh, Egypt, 603-627.Seleem T.S.T., Tawfeek M.I., El-Kelaw, H.M. 2010. Some factors affecting rabbit reproductively. The 6th Inter. Con. on Rabbit Production in Hot Climates, Assuit, Egypt, 357-376.Vernet P., Aitken R.J., Drevet J.R. 2004. Antioxidant strategies in the epididymis. Mol. Cell. 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    Networks of inter-organisational coordination during disease outbreaks

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    Multi-organisational environment is demonstrating more complexities due the ever-increasing tasks’ complications in modern environments. Disease outbreak coordination is one of these complex tasks that require multi-skilled and multi-jurisdictional agencies to coordinate in dynamic environment. This research discusses theoretical foundations and practical approaches to suggest frameworks to study complex inter-organisational networks in dynamic environments, specifically during disease outbreak. We study coo¬¬rdination as being an interdisciplinary domain, and then uses social network theory to model it. I have surveyed 70 health professionals whom have participated in the swine influenza H1N1 2009 outbreak. I collected both qualitative and quantitative data in order to build a comprehensive understanding of the dynamics of the inter-organisational network that evolved during that outbreak. Then I constructed a performance model by use three main components of the network theory: degree centrality, connectedness and tie strength as the independent variables, and disease outbreak inter-organisational performance as the dependent one. In addition, we study both the formal networks and the informal ones. Formal networks are based on the standard operating structures, and the informal ones emerge based on trust, mutual benefits and relationships. Results suggest that the proposed social network measures have positive effect on coordination performance during the outbreak in both formal and informal networks, except centrality in the formal one. In addition, none of those measures influence performance before the outbreak. Practically, the results suggest that increasing the communication frequency and diversifying the tiers of the inter-organisational links enhance the overall network’s performance in formal coordination. In the informal one, links are created with the intention to improve performance; hence, all suggested network measures improve performance

    Planning for Urban Energy Needs with A PV/WT Integrated Low-Carbon Infrastructure: A Techno-Economic and Environmental Study

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    This study presents a techno-economic feasibility analysis of implementing an autonomous hybrid renewable energy system in a university building in Saudi Arabia. The system utilizes a combination of solar panels and wind turbines to generate electricity and a storage system to manage excess energy. The economic analysis includes cost-benefit analysis, payback period, and net present value. The results show that the proposed system has a positive net present value and a payback period of fewer than 10 years. The implementation of the system is expected to reduce the university's reliance on fossil fuels and decrease its carbon footprint. Overall, the findings suggest that the adoption of an autonomous hybrid renewable energy system is a viable and financially feasible option for the university. Keywords: HOMER Software; Optimization; Solar energy; Wind energy; renewable energy. DOI: 10.7176/ISDE/12-6-05 Publication date:December 31st 2022

    Acid-Stable Electrocatalysts for the Solar Production of Fuels

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    Sunlight is one of the few renewable resources that can meet global energy demand. Unfortunately, while solar energy has grown in the past few years, several economic and scientific constraints have hindered mass adoption. One of the main obstacles solar energy faces is the lack of economically competitive storage technologies. Artificial photosynthesis is a potential solution in which solar energy is directly converted into energy dense chemical bonds that can be easily stored and transported. One impediment facing the commercialization of artificial photosynthesis is the use of expensive and rare precious metals as catalysts. This dissertation focuses on the achievements of the past five years in characterizing novel, earth-abundant, acid-stable hydrogen evolution catalysts. While nickel alloys have long been known as catalysts for the hydrogen evolution reaction in basic media, it has only been in the past decade that earth abundant catalysts that are stable in acidic media have been reported. These discoveries are critically important as the many proposed artificial photosynthetic devices require the use of acidic media. In this dissertation we examine two families of hydrogen evolution catalysts: transition metal chalcogenides (namely molybdenum and cobalt selenide) as well as transition metal phosphides (cobalt phosphide). In addition to the electrochemical characterization of these catalysts, spectroscopic characterizations were performed in order to carefully examine the chemical compositions of these catalysts before, after and during the hydrogen evolution reaction. This analysis elucidated both chemical, and structural changes that occurred after the catalysts had been subject to the hydrogen evolution reaction conditions. The final chapter in this thesis delves into the techno-economic realities of energy transportation via different fuels. Due to the strong interest in renewable energy, several future energy transportation scenarios, including 100% grid electrification and widespread installation of hydrogen pipelines, have been proposed. In order to get a fuller understanding of such potential infrastructure alternatives, we report their differing energy transportation costs.</p

    Chemical investigations of insect exocrine glands

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    The trail-following component of the trail pheromone of Pheldole pallidal a has been identified as a 3-ethy1-2,5-dimethylpyraz1ne. It is present in minor but not major workers. Another component which acts as primer appears to be required but it has not been identified. A time study of the filling of the Dufour gland of Formica sanquinea from emergence of adults for several months has shown the gland fills slowly and the composition changes with time. A re-examination of the mandibular gland secretion of Tetramorlum caespitum has shown It contains chiefly 4-methyl-3-hexano1 not 3-octanone. The Dufour glands of workers and queens of the myrmicine ants Leptothorax acervorum and Messor minor and the formicine ant Camponotus aethlops have shown little differences between the castes. Dufour glands of workers of the myrmicine species leptothorax nylanderi. Hessor capltatus, T. caespitum. Myrmica lonae. Myrmica sabuleti, Hyrmlca aloba. and Hyrmica scabrinodls. and the formicine species Formica fusca. Formica lemani, Lasius fullqlnosus, Camponotus aeqyptiacus. Camponotus vagus and Cataglyphis saviqnyl have been carried out. Examination of caespitum from a wide range of habitats has shown no significant differences In composition. For F. fusca and F. lemani. the substances of the Dufour gland enable the species to be distinguished chemically. Attempts to use Dufour gland substances to distinguish between a group of uncertain Hyrmlca species was inconclusive. The Dufour glands of major and minor workers of C. aegyptlacus have quite different composition, the former contain acetates in quantity. Attempts to study the sexual pheromone of the beetle Attaqenus scalarls were frustrated by the inability to aaintain live insects. Hexadecanoic acid, octadecano1c ac1d and octadecenoic acid were 1dent1f1ed in the body 1n sign1f1cant quant1t1es and w1ll have to be tested to see if they prov1de the pheromone
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