Reducing global warming potential (GWP) of refrigerants is needed to the decrease of ozone-depleting of refrigeration systems leakages. Refrigerant R1234yf is now used to substitute R134a inside mobile air conditioning systems. Thermodynamic properties of R1234yf are similar to R134a. Also, it has a very low GWP of 4, compared to 1430 for R134a, making it a proper choice for future automobile refrigerants. The purpose of this research is to represent the main operating and performance differences between R1234yf and R134a. Experimental analysis was carried out on the automotive air conditioning system (AACS) with 3 kW nominal capacity, to test and compare the performance of R134a with R1234yf. Experiments were accomplished for both refrigerants in almost the same working conditions and procedure with a range of ambient temperature varied from 26oC to 50oC. Parameters studied were ambient temperature, type of refrigerant in the system at compressor speed 1450 rpm, and internal thermal loads of passenger room. The performance characteristics of the system, including COP and cooling capacity, were studied by changing different parameters. The results show that COP of R134a is higher than R1234yf by 12.6%, while the refrigeration effect of R134a is higher than R1234yf by 25%. This shows that R1234yf is a suitable and good candidate for drop-in replacement of R134a in AACS.
The magnetic properties of a pure Nickel metal and Nickel-Zinc-Manganese ferrites having the chemical formula Ni0.1(Zn0.4Mn0.6)0.9Fe2O4 were studied. The phase formation and crystal structure was studied by using x-ray diffraction which confirmed the formation of pure single spinel cubic phase with space group (Fd3m) in the ferrite. The samples microstructure was studied with scanning electron microstructure and EDX. The magnetic properties of the ferrite and nickel metal were characterized by using a laboratory setup with a magnetic field in the range from 0-500 G. The ferrite showed perfect soft spinel phase behavior while the nickel sample showed higher magnetic loss an
... Show MoreConvolutional Neural Networks (CNN) have high performance in the fields of object recognition and classification. The strength of CNNs comes from the fact that they are able to extract information from raw-pixel content and learn features automatically. Feature extraction and classification algorithms can be either hand-crafted or Deep Learning (DL) based. DL detection approaches can be either two stages (region proposal approaches) detector or a single stage (non-region proposal approach) detector. Region proposal-based techniques include R-CNN, Fast RCNN, and Faster RCNN. Non-region proposal-based techniques include Single Shot Detector (SSD) and You Only Look Once (YOLO). We are going to compare the speed and accuracy of Faster RCNN,
... Show MoreHuman beta-defenses (hBDs) are antimicrobial peptides involved in innate immune protection, and their association with the risk of respiratory allergy has been proposed. Therefore, this study sought to evaluate this association in allergic rhinitis (AR) and asthma (AS) of Iraqi patients. A case-control study was conducted to investigate serum levels of hBD1, hBD2, hBD3, and hBD4 in 52 AR and 60 AS patients and 61 healthy controls (HC). The hBDs were determined using enzyme-linked immunosorbent assay kits. Results revealed that median levels of hBD1, hBD2, and hBD3 were significantly elevated in the serum of AR and AS patients compared with HC (p < 0.01). Levels of hBD4 were also elevated in AR and AS patients but the differen
... Show MoreAs Alkaloids known for their pharmaceutical importance; this research included the extraction of crude alkaloids of three plants (Zingiber officinale Roscoe., Thymus vulgaris L. and Acacia arabica L.) and evaluate their activity as coagulant agent by using three degraded concentrations of each plant extract and tested them on lab mice through the observation of the variations in bleeding time (BT), clotting time (CT) and platelet count. The results revealed differences in the percentage of alkaloids in the plants under the study; Z. officinale extract was the higher one followed by T. vulgaris and A. arabica respectively. Z. officinale extract was also the most effective plant as coagulant factor than other two plants as it decreased bot
... Show MoreIn The Name of Allah Most Gracious Most Merciful
Scholars, past and present, have paid attention to the books of Fasting and Hajj, and they have compiled literature on that, and they have written treatises and researches. The best days, and as for the pilgrimage, it is one of the great pillars of Islam, which God Almighty has distinguished by making its rituals in the best of places, which is the Sacred House of God.
The research studies the melodic and rhythmic characteristics of monologue, in addition to how it was transferred from the Arab homeland to Iraq and reviewed its most prominent performers, as well as a review of the monologue types and their propagation in the Arab homeland such as comical, dramatic, and political and guidance monologues.
The methodological framework included: the problem of the research, the importance of the research and the objective of the research which is to uncover the melodic and rhythmic structure of the monologue in Iraq. The limits of the research included the objective limit tackling the art of monologue and the spatial limit which is Baghdad
... Show MoreAnaemia is one of the most important problems of malnutrition in the world, especially in countries developing and anemia is associated inextricably important public health and HIV and morbidity and reduced mental capacity This study aims to determine the incidence of anemia for the period 1999-2000 among healthy adults outwardly and its relationship with some variablesjob related study sample included 200 male and 200 Antymn but the cities of Baghdad and Baquba reviewers for central labs
Image compression is an important tool to reduce the bandwidth and storage
requirements of practical image systems. To reduce the increasing demand of storage
space and transmission time compression techniques are the need of the day. Discrete
time wavelet transforms based image codec using Set Partitioning In Hierarchical
Trees (SPIHT) is implemented in this paper. Mean Square Error (MSE), Peak Signal
to Noise Ratio (PSNR) and Maximum Difference (MD) are used to measure the
picture quality of reconstructed image. MSE and PSNR are the most common picture
quality measures. Different kinds of test images are assessed in this work with
different compression ratios. The results show the high efficiency of SPIHT algori
Background:
Angiogenic potential m most tumors; characterized by VEGF and vascular bed density around tumor islands, is believed to be an important marker in predicting tumor growth,
recurrence and metastasis.
Materials and Methods:
The study included 50 cases of ameloblastomas. From each case 4 μm sections were stained IHC with antivascular endothelial growth factor antibody- and endothelial lined
vessels anti CD34 antibody to evaluate their expression and intensity in relation to their Fac Med Baghdad clinicopathological features.
Results:
Generally, VEGF was significantly highly expressed with strong intensity in outer cell layer of tumor islands, and the newly formed blood vessels were signif