900 research outputs found

    Waste heat recovery from adiabatic diesel engines by exhaust-driven Brayton cycles

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    An evaluation of Bryton Bottoming Systems (BBS) as waste heat recovery devices for future adiabatic diesel engines in heavy duty trucks is presented. Parametric studies were performed to evaluate the influence of external and internal design parameters on BBS performance. Conceptual design and trade-off studies were undertaken to estimate the optimum configuration, size, and cost of major hardware components. The potential annual fuel savings of long-haul trucks equipped with BBS were estimated. The addition of a BBS to a turbocharged, nonaftercooled adiabatic engine would improve fuel economy by as much as 12%. In comparison with an aftercooled, turbocompound engine, the BBS-equipped turbocharged engine would offer a 4.4% fuel economy advantage. If installed in tandem with an aftercooled turbocompound engine, the BBS could effect a 7.2% fuel economy improvement. The cost of a mass-produced 38 Bhp BBS is estimated at about $6460 or 170/Bhp. Technical and economic barriers that hinder the commercial introduction of bottoming systems were identified. Related studies in the area of waste heat recovery from adiabatic diesel engines and NASA-CR-168255 (Steam Rankine) and CR-168256 (Organic Rankine)

    Interactive Two-Stage Stochastic fuzzy Rough Programming for Water Resources Management

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    This paper deals with a fuzzy programming approach for treating an interactive two-stage stochastic rough-interval water resource management. The approach has been developed by incorporating an interactive fuzzy resolution method within a rough two-stage stochastic programming framework. The approach can not only tackle dual rough intervals presented as an inexact boundary intervals that exist in the objective function and the left- and right-hand sides of the constraints that are associated with different levels of economic penalties when the promised policy targets are violated. The results indicate that a set of solutions under different feasibility degrees has been generated for planning the water resources allocation. They can help the decision makers to conduct in depth analysis of tradeoffs between economic efficiency and constraint-violation risk, as well as enable them to identify, in an interactive way, a desired compromise between satisfaction degree of the goal and feasibility of the constraints. A management example in terms of rough-intervals water resources allocation has been treated for the sake of applicability of the proposed approach

    Minimum Viscosity for Bearing Reliability in Rotary Compressors

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    Chromohysteroscopy after failed intracytoplasmic sperm injection

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    Background: ICSI is the injection of a single sperm directly into the cytoplasm of the oocyte (ICSI). The failure to achieve pregnancy after ICSI has been studied over many years to reach the possible and preventable causes to avoid another failure. The aim of this study was to assess the value of using Chromohysteroscopy as a part of the work up of cases with one or more failed ICSI. The Ultimate goal is to detect the possible endometrial abnormalities and /or endometritis.Methods: Prospective cohort study was carried out with total of 50 infertile women recruited from infertility clinic in Elshatby Maternity University Hospital, Alexandria University, Egypt. Cases were allocated in 2 groups with 25 cases in each group. The first group included cases that had a failed trial of ICSI. The second group included control cases who were seeking for fertility treatment with no previous history of ICSI or any uterine surgery or anatomical abnormalities. In the postmenstrual period, Chromohysteroscopy was done by the same surgeon and documentation of all findings in the cavity and presence of endometritis.Results: There was a significant increase in the incidence of endometritis among the study group 68% in comparison to 16% in the control group.Conclusions: In this study endometrial dying with methylene blue at hysteroscopy improve the detection of chronic endometritis

    Border Gateway Protocol to provide failover in multihoming environment

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    Nowadays Internet access across the globe is very crucial because of the huge size of useful data that the Internet stores. This stimulates most ISPs to choose a reliable routing protocol in order to preserve the security and guarantee of customer’s data on the Internet. By multi-homing a network using BGP, a more control of balancing the traffic load and achieving redundancy becomes possible. This will enhance network performance, quality throughput and better routing policies on the Internet. Single-homed Internet communication link between networks’ Internet service provider does not inspire with confidence because of excessive traffic and device or human error that may arise. We use BGP because of its ability to choose the best path to a destination particularly in a Multihoming environment. Our simulation results are achieved using GNS3 emulator and Wireshark network analyser. We carried out two simulations to run BGP Multihoming to the same service provider and to different service provider. In both scenarios we run the simulations in failover mode and in load-shearing mode. Simulation results show that BGP Multihoming to different service providers provides failover to ISP networks. For a home and enterprise network to have a certain level of failover or redundancy there is a need to employ the use of BGP Multihoming to different service provider

    Performance of Turbo Code in CDMA under AWGN Channel

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    Carrier Division Multiple Access is considered as an efficient technique in wireless communication due to its high possibility to serve an unlimited number of users. CDMA uses the same frequency concurrently with wireless communication. In this paper, the performance and evaluation of turbo code are duly presented followed by the examination of CDMA under AWGN channel was highlighted. The simulation estimated to achieve bit error rate of less than 10-2 frame size. To this end, the results of the simulation show that the Bit Error Rate is inversely proportional to the size of the frame and directly proportional the number of iteration in the decoder

    Diagnostic performance of loop-mediated isothermal amplification (LAMP) and Ultra-sensitive PCR in diagnosis of malaria in western Saudi Arabia

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    Malaria diagnosis continues to be one of the most important steps in the cycle of control specially in endemic countries with low parasitic load infections. Loop-mediated isothermal amplification (LAMP) and ultrasensitive PCR (Us-PCR) are two promising candidates for malaria diagnosis. A cross sectional study performed at King Faisal Hospital, Taif KSA involved patients suffering from signs and symptoms suggesting of malaria, 35 blood samples diagnosed by Nested Multiplex PCR as a reference method (13 P. falciparum, 17 P. vivax, 3 mixed P. falciparum and P. vivax) plus two negative controls were selected to be included in this study to analyse the performance of two LAMP methods (LAMP OptiGene® and LAMP WarmStart®) and two ultrasensitive PCRs (Us-PCR TARE-2 and Us-PCR Var-ATS). LAMP OptiGene® and LAMP WarmStart® performances were identical and better than the performance of Us PCR TARE 2 and Us-PCR var-ATS for P. falciparum, achieving 93.75% sensitivity, 100% specificity and 97.17% accuracy versus 87.5% sensitivity, 100% specificity and 94.29% accuracy for the Us PCR TARE 2 and 81.25% sensitivity, 94.74% specificity and 88.57% accuracy for the Us PCR var-ATS respectively. In P. vivax diagnosis LAMP OptiGene® performed excellently with 100% sensitivity, specificity, and accuracy while LAMP WarmStart® and Us-PCR Cox1 achieved 100% sensitivity, specificity 93.33% and 97.14% accuracy. The study results highlighted the benefits of using LAMP techniques for field diagnosis of malaria in different settings where the need for a more sensitive and reliable molecular tool is mandatory but at the same time removing the high cost, long turnaround time and the need of highly specialized trained technicians to perform more sophisticated molecular techniques.The authors would like to acknowledge The Deanship of Scientific Research, Taif University, Taif, Saudi Arabia for funding of the resent research.S

    The role of social networks in students’ learning experiences

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    The aim of this research is to investigate the role of social networks in computer science education. The Internet shows great potential for enhancing collaboration between people and the role of social software has become increasingly relevant in recent years. This research focuses on analyzing the role that social networks play in students’ learning experiences. The construction of students’ social networks, the evolution of these networks, and their effects on the students’ learning experience in a university environment are examined

    City-wide wastewater genomic surveillance through the successive emergence of SARS-CoV-2 Alpha and Delta variants

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    Genomic surveillance of SARS-CoV-2 has provided a critical evidence base for public health decisions throughout the pandemic. Sequencing data from clinical cases has helped to understand disease transmission and the spread of novel variants. Genomic wastewater surveillance can offer important, complementary information by providing frequency estimates of all variants circulating in a population without sampling biases. Here we show that genomic SARS-CoV-2 wastewater surveillance can detect fine-scale differences within urban centres, specifically within the city of Liverpool, UK, during the emergence of Alpha and Delta variants between November 2020 and June 2021. Furthermore, wastewater and clinical sequencing match well in the estimated timing of new variant rises and the first detection of a new variant in a given area may occur in either clinical or wastewater samples. The study's main limitation was sample quality when infection prevalence was low in spring 2021, resulting in a lower resolution of the rise of the Delta variant compared to the rise of the Alpha variant in the previous winter. The correspondence between wastewater and clinical variant frequencies demonstrates the reliability of wastewater surveillance. However, discrepancies in the first detection of the Alpha variant between the two approaches highlight that wastewater monitoring can also capture missing information, possibly resulting from asymptomatic cases or communities less engaged with testing programmes, as found by a simultaneous surge testing effort across the city
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