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.
Wireless Multimedia Sensor Networks (WMSNs) are networks of wirelessly interconnected sensor nodes equipped with multimedia devices, such as cameras and microphones. Thus a WMSN will have the capability to transmit multimedia data, such as video and audio streams, still images, and scalar data from the environment. Most applications of WMSNs require the delivery of multimedia information with a certain level of Quality of Service (QoS). This is a challenging task because multimedia applications typically produce huge volumes of data requiring high transmission rates and extensive processing; the high data transmission rate of WMSNs usually leads to congestion, which in turn reduces the Quality of Service (QoS) of multimedia appli
... Show MoreThe present study addresses the behavior of gases in cultivation media as an essential factor to develop the relationship between the microorganisms that are present in the same environment. This relationship was explained via mass transfer of those gases to be a reasonable driving force in changing biological trends. Stripping and dissolution of oxygen and carbon dioxide in water and dairy wastewater were investigated in this study. Bubble column bioreactor under thermal control system was constructed and used for these processes. The experimental results showed that the removal of gases from the culture media requires more time than the dissolution. For example, the volumetric mass transfer coefficient for the removal
... Show MoreThe unemployment is considered from the most danger problems that our society face them in current time & in the near future , because it makes prodigality for element of human being , particularly age of youth who have ability to work & producing , that resulted in negative effects forecast to dire consequences social and economical dangers . In the same time as will be stated in our explanation in the following in our research , because the unemployment has ability to help to prepare good environment to grow crime , actions of violence that mostly are main cause to decrease living level of majority of citizens & in increasing numbers who became under poverty , the unemployment is economical problem as it is psycholo
... Show MorePolyaniline films were successfully synthesized in this study using an oxidative polymerization method at temperatures ranging from 0 to 4 ° C. Polyaniline films were deposited using a single step of chemical oxidative polymerization rather than electrochemical polymerization. The polyaniline was examined using FTIR, XRD, SEM, AFM, and Four Point Probe. This result demonstrates that polyaniline synthesized using this method has a uniform morphology, small size (17 to 40) nm, high crystallinity, and high conductivity (9.42 s/cm).
Background: The excess mortality associated with
rheumatoid arthritis is largely due to
cardiovascular disease. Rheumatoid arthritis is of
primary importance in atherogenesis. The intimamedia thickness of extracranial carotid arteries is a
measurable index of the presence of
atherosclerosis.
Objective: To assess carotid intima-media
thickness in rheumatoid arthritis by Doppler
ultrasound.
Methods: Fifty two Iraqi patients with rheumatoid
arthritis were studied and compared with another
fifty two, healthy individuals matched for age and
sex as a control group. Full history was taken and
complete clinical examination was done for all
individuals in both groups. Rheumatoid arthritis
diagnosis was
Abstract: The utility of DNA sequencing in diagnosing and prognosis of diseases is vital for assessing the risk of genetic disorders, particularly for asymptomatic individuals with a genetic predisposition. Such diagnostic approaches are integral in guiding health and lifestyle decisions and preparing families with the necessary foreknowledge to anticipate potential genetic abnormalities. The present study explores implementing a define-by-run deep learning (DL) model optimized using the Tree-structured Parzen estimator algorithm to enhance the precision of genetic diagnostic tools. Unlike conventional models, the define-by-run model bolsters accuracy through dynamic adaptation to data during the learning process and iterative optimization
... Show MoreEichhornia, or water hyacinth represents a serious threat to potable water basins. This problem is materialized majorly in consuming large amounts of water and dissolved Oxygen that is necessary for aquatic life, and minorly in hindering water streams. Even there are limited trials to overcome such pests, none of them presents an acceptable solution economically and logically. Chlorine is a well-known biocide and broadly used in water industry. It could give a possible method to fight such weed. To investigate that, concentration-time plot should be introduced similar to any other microorganisms; especially, bacteria in water. In this work, various doses of Chlorine along various time
English teachers in Iraq and other countries around the world up to this time use traditional methods to help students memorize new vocabularies. The sense of words or structure is not to be given in either the native tongue or the target language by definition, but is induced by the way the form is used in the situation. Situational Language Teaching (SLT) has recently become the needed method for improving speaking skills. It indicates the application of learning the language in actual and social exchange expressions so as to let learners do as required in classroom and non-classroom circumstances. This pilot study seeks to answer the following questions: Can SLT improve English speaking skills of target learners? How SLT contribute to th
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