Phase change material (PCM) is considered as one of the most effective thermal energy storage (TES) systems to balance energy supply and demand. A key challenge in designing efficient PCM-based TES systems lies in the enhancement of heat transmission during phase transition. This study numerically examines the privilege of employing twisted-fin arrays inside a shell-and-tube latent heat storage unit to improve the solidification performance. The presence of twisted fins contributes to the dominating role of heat conduction by their curved shapes, which restricts the role of natural convection but largely aids the overall heat-transfer process during solidification. The heat-discharge rate of twisted-fin configuration is increased by ∼14 and ∼55% compared to straight fin and no fin configurations—leading to a reduction in the solidification duration by ∼13 and ∼35%, respectively. The solidification front at various times has also been assessed through a detailed parametric study over the fin height, fin pitch number, and fin thickness. Over the range of values assumed, the fin height is the most dominant parameter – increasing the heat-retrieval rate from 10.0 to 11.4 W and decreasing the discharge time from above 3600 to 2880 s by varying the fin height from 2.5 to 7.5 mm.
The research aims to define the main and subsidiary criteria for evaluating the industrial market sectors and proposing a model for arranging these criteria according to priority and knowing the highest criteria in terms of relative importance in the General Company for Automobile Trade and Machinery, and for the purpose of establishing this model, experiences in the concerned company were approved, and this study proposes a multi-criteria decision model According to the FEAHP, the expanded fuzzy hierarchical analysis method enables the commercial company to develop clear strategic policies on which the company’s management system depends on determining criteria for evaluating and selecting market sectors and making appropriate
... Show MoreThe figure of personality modes determines its privileged style in the use of modern and advanced technological tools in the process of changing and developing in order to keep up with that. The proses of selection and choosing administrators in the appropriate places are the most important functions of senior management because it is easy to adopt factory buildings or establishments But this is a human world as that of machines world. So it is required to have people in the process of changing those who have a time, Knowledge, skill, ability and strong administrative personal skills, those people (leaders) should to put a clear vision for the selection and application of the change efforts and to create the necessary climate and
... Show MoreA field experiment was carried out to test the efficiency of potassium silicate and wild eggplant
Background: Generally, genetic disorders are a leading cause of spontaneous abortion, neonatal death, increased morbidity and mortality in children and adults as well. They a significant health care and psychosocial burden for the patient, the family, the healthcare system and the community as a whole. Chromosomal abnormalities occur much more frequently than is generally appreciated. It is estimated that approximately 1 of 200 newborn infants had some form of chromosomal abnormality. The figure is much higher in fetuses that do not survive to term. It is estimated that in 50% of first trimester abortions, the fetus has a chromosomal abnormality. Aim of the study: This study aims to shed some light on the results of chromosomal studies per
... Show MoreCooperation spectrum sensing in cognitive radio networks has an analogy to a distributed decision in wireless sensor networks, where each sensor make local decision and those decision result are reported to a fusion center to give the final decision according to some fusion rules. In this paper the performance of cooperative spectrum sensing examines using new optimization strategy to find optimal weight and threshold curves that enables each secondary user senses the spectrum environment independently according to a floating threshold with respect to his local environment. Our proposed approach depends on proving the convexity of the famous optimization problem in cooperative spectrum sensing that stated maximizing the probability of detec
... Show MoreExperimental and theoretical investigations are presented on flocculation process in pulsator clarifier. Experimental system was designed to study the factors that affecting the performance of pulsator clarifier. These factors were water level in vacuum chamber which range from 60 to 150 cm , rising time of water in vacuum chamber which having times of 20,30 & 40 seconds , and sludge blanket height which having heights of 20,30 & 40 cm .The turbidity and pH of raw water used were 200 NTU and 8.13 respectively. According to the jar test, the alum dose required for this turbidity was 20 mg/l .The performance parameters of pulsator clarifier such as , turbidity ,total solid TS , shear rate , volume concentration of sludge blanket an
... Show MoreTransport layer is responsible for delivering data to the appropriate application process on the host computers. The two most popular transport layer protocols are Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). TCP is considered one of the most important protocols in the Internet. UDP is a minimal message-oriented Transport Layer protocol. In this paper we have compared the performance of TCP and UDP on the wired network. Network Simulator (NS2) has been used for performance Comparison since it is preferred by the networking research community. Constant bit rate (CBR) traffic used for both TCP and UDP protocols.
Undoubtedly, Road Traffic Accidents (RTAs) are a major dilemma in term of mortality and morbidity facing the road users as well as the traffic and road authorities. Since 2002, the population in Iraq has increased by 49 percent and the number of vehicles by three folds. Consequently, these increases were unfortunately combined with rising the RTAs number, mortality and morbidity. Alongside the humanitarian tragedies, every year, there are considerable economic losses in Iraq lost due to the epidemic of RTAs. Given the necessity of understanding the contributory factors related to RTAs for the implementation by traffic and road authorities to improve the road safety, the necessity have been a rise for
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