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Assessment of using different ozone-friendly R22 alternative refrigerants in residential air conditioners in a high-ambient temperature country
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Abstract<p>The performance of a vapor compression refrigeration system (VCRS)-based residential air conditioner operating in a high-ambient temperature (HAT) country was investigated using six zero-ODP (ozone depletion potential) refrigerants as replacements to R22. The non-flammable alternative refrigerants considered in the present research were R134a, R404A, R407C, R410A, R448A, and R507A. Using the basic conservation laws, the VCRS was modeled during steady-state operation and solved using engineering equation solver (EES) software. Coefficient of performance (COP), pressures and temperatures at compressor suction and discharge, Global Warming Potential (GWP), critical pressure and temperature, compressor pressure ratio, volumetric cooling capacity (VCC) specific cooling capacity (SCC), and refrigeration effect were utilized as assessment criteria for the alternative refrigerants considered. From these refrigerants, the highest values of suction pressure, discharge temperature, and condenser pressure were attained by R410A. In addition, the discharge temperatures for all refrigerants, except R134a, were all higher than their corresponding critical values, causing a quicker drop in the VCRS’s performance. As an alternative refrigerant, R407C showed the highest SCC of 141.0 kJ/kg followed directly by 139.2 and 138.0 kJ/kg for R410A and R448A, respectively. A reverse trend was found for VCC with respective values of 4722 and 3775 kJ/m<sup>3</sup> for R410A and R448A. Lower volume flow rates and smaller-sized compressors are expected for higher VCC refrigerants. The same trend was found for the compressor’s specific work input and condenser’s specific heat transfer with values of (51.14, 46.82, and 45.38 kJ/kg) and (190.3, 187.8, and 183.4 kJ/kg) for R410A, R407C, and R448A, respectively. For applications in HAT countries, larger condenser’s specific heat transfer makes the refrigerant more applicable. Conversely, with respect to COP, refrigerant R134a with a value of 3.075 was the superior alternative followed by R448A and R407C with respective COPs of 3.042 and 3.011. Based on the overall assessment in terms of environmental obligation, COP, compressor input power, refrigerant flow rate required, and all the evaluations made in this research, refrigerant R448A was recommended as the most appropriate substitute to R22 which can effectively be used in residential air conditioners in a HAT country.</p>
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Publication Date
Thu Oct 15 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Assessment of tongue space area in a sample of Iraqi adults with class I dental and skeletal pattern
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Background: Lateral cephalometric radiography is commonly used as a standard tool in orthodontic assessment and treatment planning. This study aimed to determine the tongue and surrounding space area in a sample of Iraqi adults with class I dental and skeletal pattern. Materials and methods: The study included thirty healthy subjects (15 males and 15 females) with an age ranged between 23-34 years and class I dental and skeletal pattern with no history of any sleep related disorders. The assessed cephalometric measurement included length and height of the tongue and position of hyoid bone from cervical line. Descriptive statistics were obtained for the data. Genders difference was evaluated by independent sample t-test. Results: There wer

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Publication Date
Wed Jan 03 2024
Journal Name
Al-rafidain Journal Of Medical Sciences ( Issn 2789-3219 )
Assessment of Adherence and Self-Efficacy in a Sample of Iraqi Patients Receiving Warfarin or Direct Oral Anticoagulants
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Background: While warfarin and direct oral anticoagulants (DOACs) are used to manage thromboembolic events, they possess several features that impact adherence. Objective: To assess medication adherence and self-efficacy in patients receiving warfarin or DOAC treatment. Methods: A cross-sectional study was performed at Ibn Al-Bitar Hospital in Baghdad from December 2022 to May 2023 on patients receiving either warfarin or DOACs. The Arabic version of the Adherence to Refills and Medications Scale (ARMS) questionnaire and the Self-Efficacy for Managing Chronic Disease 6-Item Scale (SES6C) questionnaire were used to assess adherence and self-efficacy. Results: 181 patients were enrolled in the study, of whom 56.9% received warfarin an

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Publication Date
Thu Oct 15 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Validity of computed tomographic in assessment of genial tubercle and anterior mandible as a reference guide to locate osteotomy in genioglossus advancement
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Background: Genioglossus advancement is a surgical procedure to advance the tongue in some patients with obstructive sleep apnea syndrome.The important step in this procedure is that of accurately capturing the bone segment attached to the genioglossus muscle to avoid complications such as mandibular fracture, devitalization of the inferior incisor roots, and incomplete incorporation of the genioglossus Materials and Method: Computed tomography scans were taken for 53 Iraqi adult patients (28 male and 25 female) range from (18-35) years with skeletal class I classification and intact anterior mandible dentition included in this study using sagittal and axial sections. The measurements were done for genial tubercle and anterior mandibular re

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Publication Date
Mon Jul 14 2025
Journal Name
Gsc Advanced Research And Reviews
air Pollution from Fertilizer Aitrogen
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An essential component of food production is nitrogen (N). Crops waste about half of the nitrogen fertilizer input, which is then released into the atmosphere as gas emissions or polluting of aquatic groups. It is necessary to reach manufacture stages that promote world food security in the absence of compromising quality. safety of the environment. It is estimated that by 2050, N pollution levels will have risen 150% from 2010 levels, with the The agricultural sector is responsible for 60% of this growth. In this review fertilizer Nitrogen should take into account while discussing air pollution caused by gases that contain nitrogen, which might result in issues like the greenhouse effect . Nopoint pollution, the involvement of farmer manag

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Publication Date
Wed Jul 30 2025
Journal Name
Gsc Advanced Research And Reviews
Air pollution from fertilizer nitrogen
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An essential component of food production is nitrogen (N). Crops waste about half of the nitrogen fertilizer input, which is then released into the atmosphere as gas emissions or polluting of aquatic groups. It is necessary to reach manufacture stages that promote world food security in the absence of compromising quality. safety of the environment. It is estimated that by 2050, N pollution levels will have risen 150% from 2010 levels, with the The agricultural sector is responsible for 60% of this growth. In this review fertilizer Nitrogen should take into account while discussing air pollution caused by gases that contain nitrogen, which might result in issues like the greenhouse effect. Nopoint pollution, the involvement of farme

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Publication Date
Wed Sep 30 2015
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Problems of Heavy Oil Transportation in Pipelines And Reduction of High Viscosity
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Drag has long been identified as the main reason for the loss of energy in fluid transmission like pipelines and other similar transportation channels. The main contributor to this drag is the viscosity as well as friction against the pipe walls, which will results in more pumping power consumption.

   The aim in this study was first to understand the role of additives in the viscosity reduction and secondly to evaluate the drag reduction efficiency when blending with different solvents.

   This research investigated flow increase (%FI) in heavy oil at different flow rates (2 to 10 m3/hr) in two pipes (0.0381 m & 0.0508 m) ID By using different additives (toluene and naphtha) with different concent

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Publication Date
Thu Sep 01 2022
Journal Name
Jordan Journal Of Mechanical And Industrial Engineering
Empact of Discrete Multi-arc Rib Roughness on the Effective Efficiency of a Solar Air Heater
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Artificial roughness on the absorber plate of a Solar Air Heater (SAH) is a popular technique for increasing its effective efficiency. The study investigated the effect of geometrical parameters of discrete multi-arc ribs (DMAR) installed below the SAH absorber plate on the effective efficiency. The effects of major roughness factors, such as number of gaps (Ng = 1-4), rib pitch (p/e = 4-16), rib height (e/D = 0.018-0.045), gab width (wg/e = 0.5-2), angle of attack ( = 30-75), and Reynolds number (Re= 2000-20000) on the performance of a SAH are studied. The performance of the SAH is evaluated using a top-down iterative technique. The results show that as Re rises, SAH-effective DMAR's efficiency first ascends to a specified value o

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Publication Date
Sun Jan 30 2022
Journal Name
Heat Transfer
Theoretical and experimental investigation of a heat pipe heat exchanger for energy recovery of exhaust air
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Heat pipes and two‐phase thermosyphon systems are passive heat transfer systems that employ a two‐phase cycle of a working fluid within a completely sealed system. Consequently, heat exchangers based on heat pipes have low thermal resistance and high effective thermal conductivity, which can reach up to the order of (105 W/(m K)). In energy recovery systems where the two streams should be unmixed, such as airconditioning systems of biological laboratories and operating rooms in hospitals, heat pipe heat exchangers (HPHEs) are recommended. In this study, an experimental and theoretical study was carried out on the thermal performance of an air‐to‐air HPHE filled with two refrigerants as working fluids, R22 and R407c. The heat pipe he

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Publication Date
Sun Dec 01 2013
Journal Name
Baghdad Science Journal
Food dyes as an alternative tracking dye for DNA gel electrophoresis
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The chemical, physical and toxicological effects on health of synthetic dyes that used as tracking dye in the electrophoresis requires seriously search about alternative tracking dye. The present study is aimed to find an alternative dye from safe food dyes which commonly used in food coloring. Five dyes were selected depending on their chemical properties and the availability in local market: Brilliant Blue FCF, Tartrazine, Sunset Yellow FCF, Carmoisine, and green traditional, three dyes were chosen to be mixed as loading buffer: Brilliant Blue FCF, Sunset Yellow FCF as a basic because it give the whole range size of most traditional loading buffers that available in market, and adding the Carmoisine as a new indicator for the bands less t

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Publication Date
Sat Aug 01 2020
Journal Name
Key Engineering Materials
Compressive Strength Performance of Reactive Powder Concrete Using Different Types of Materials as a Partial Replacement of Fine Aggregate
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Reactive Powder Concrete (RPC) can be incorporate as a one of the most important and progressive concrete technology. It is a special type of ultra-high strength concrete (UHSC) that’s exclude the coarse aggregate from its constitutive materials. In this research an experimental study had been carried out to investigate the effect of using three types of materials (porcelain aggregate) and others sustainable materials (glass waste and granular activated carbon) as a partial replacement of fine aggregate. Four percentages had considered (0, 10, 15 and 20) % to achieve better understanding for the influence of these materials upon the compressive strength of RPC. Four curing ages had included in this study, these are; 7, 28, 60 and

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