Refrigerant R134a has been widely utilized in automotive air conditioning systems (AACSs); R134a has a high global warming potential (GWP) of 1430 despite having zero ozone depletion potential (ODP). Coming refrigeration systems must include refrigerants with low GWP and zero ODP. The aim of this experimental study is to evaluate the thermal performance of an (AAC) with different values of compressor speeds, i.e., (1000, 1700, and 2400 rpm) and two thermal loads, i.e., (500 and 1000 Watt) with the absence and presence of liquid suction heat exchanger (LSHX) using R134a. The results showed that adding LSHX enhanced the COP cycle by 7.18%, 10.7%, and 3.09% for the first, second, and third speed, respectively, at 500 Watt, while the enhancements were 10.27 %, 23.3 %, and 11.5 % for the first, second, and third speed, respectively, at 1000 Watt. Increasing the compressor speed decreased COP due to a reduction in RE and increased the compression effect, increasing the work done by the motor on the compressor that caused a reduction in COP. The compressor exergy destruction (X des. Comp.) decreased when LSHX was added by 6.13%, 2.22%, and 18.8% for the first, second, and third speed, respectively. However, X des. comp. increased with compressor speed due to the system’s pressure difference rise because of decreasing evaporation and increasing condensation pressures. As a result, the entropy generation increased. The increase in discharge temperature and pressure of the compressor led to a high friction force between the moving part of the compressor and the refrigerant, so the energy losses increased. Increasing the compressor speed decreased the total exergy performance of the cycle by 5.8 %, 7.5 %, and 16.7 % for the first, second, and third speed, respectively, due to increasing the compressor discharge temperature, increasing the X des. comp. and thermostatic expansion device and decreasing condenser and evaporator. Increasing X des. comp was higher than the destruction in the condenser and evaporator, which canceled the effect of others, so the total exergy performance of the cycle decreased.
Business incubator is a new effective mechanism in developing small projects through its introductions of a new integral system of services. It aims at supporting and developing making new projects. Hence, there is a big number of factors that are interrelated in the processes of preparation for those projects. Those factors are: organizing the incubator and the market available for the projects attached to them and the work programs which will have to be implemented. Those small projects represent more than 98% of the total work institutions in the world. Also it has become responsible for a ration reaching half of the national output of those countries. These projects have created between 40 to 80% of job opportunities availabl
... Show MoreRealizing robust interconnectivity in a rapidly changing network topology is a challenging issue. This problem is escalating with the existence of constrained devices in a vehicular environment. Several standards have been developed to support reliable communication between vehicular nodes as the IEEE 1609 WAVE stack. Mitigating the impact of security/mobility protocols on limited capability nodes is a crucial aspect. This paper examines the burden of maintaining authenticity service that associated with each handover process in a vehicular network. Accordingly, a network virtualization-based infrastructure is proposed which tackles the overhead of IEEE 1906 WAVE standard on constrained devices existed in vehicular network. The virtualized
... Show MoreThere continues to be a need for an in-situ sensor system to monitor the engine oil of internal combustion engines. Engine oil needs to be monitored for contaminants and depletion of additives. While various sensor systems have been designed and evaluated, there is still a need to develop and evaluate new sensing technologies. This study evaluated Terahertz time-domain spectroscopy (THz-TDS) for the identification and estimation of the glycol contamination of automotive engine oil. Glycol contamination is a result of a gasket or seal leak allowing coolant to enter an engine and mix with the engine oil. An engine oil intended for use in both diesel and gasoline engines was obtained. Fresh engine oil samples were contaminated with fou
... Show MoreSystem is one of the concepts that fused stages of human thought his contemplations , and the evolution of his ideas and know the universe and existence , was formed several systems and numerous multi- humanitarian field , for example : the political system , the economic system , the system of philosophical , scientific system ... etc. .The current research around trying to find the identity of the system aesthetic in general and theater in particular , the detection of compositions and how Cklath within shifts functional and conceptual , which confirms the importance of Altgria creative as characterized by the following heading towards experimentation and update ongoing , and in particular what we find in the discourse of postmodernism
... Show MoreThis study sheds light on female entrepreneurship in Palestine, and explores the reasons behind its relative weakness as compared with men, and with female entrepreneurship in other countries. This study aims at proposing effective policies and doable measures to enhance female entrepreneurship. Achieving this objective will carry significant impact on employment and economic growth at large, and increase women’s economic participation, scaling up their independence, and demonstrating their skills and abilities, and putting women on an equal footing with men. Furthermore, entrepreneurial activity has increasingly become one of the key drivers of economic development. An increased rate of entrepreneurial activities among women,
... Show MoreIn the geotechnical engineering applications, precise understandings are yet to be established on the effects of a foundation stiffness on its bearing capacity and settlement. The modern foundation construction uses the new available construction materials that totally change the relative stiffness of the footing structures-soil interactions such as waste material and landfill area of more residential purposes. Conventional bearing capacity equations were dealt with common rigid footing and thus cannot be used for reduced foundation rigidity. Therefore, this study investigates the effects of foundation relative stiffness on its load-displacement behaviour and the soil deformation field using compression test of a strip smooth footings on su
... Show MoreKE Sharquie, SA Al-Mashhadani, AA Noaimi, MY Abbas, Journal of the Saudi Society of Dermatology & Dermatologic Surgery, 2011 - Cited by 5
This research aim to present theoretical and philosophical framework regards topic of intellectual capital readiness in Iraqi universities. That is, by using strategic map in balanced score card of Norton and Kaplan (2004). This research discusses theoretical content for three main aspects reflect in its nature elements of intellectual capital readiness in organizations. This includes human capital readiness, information capital readiness and organizational capital readiness. To clear each element, the authors relay on mechanism to determine gape per element of intellectual capital elements.