Preferred Language
Articles
/
joe-668
The Experimental Assessment of R134a and Its Lower GWP Alternative R1234yf in an Automobile Air Conditioning System
...Show More Authors

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.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Sat Dec 30 2023
Journal Name
مجلة الذكوات البيض
Assessing Accuracy and Interaction in a Speaking Test : AN Analytical study. تقييم الدقة و التفاعل في اختبار المحادثة: دراسة تحليلية
...Show More Authors

This paper deals with one of the most important issues in a foreign language teaching and learning, i.e. speaking test assessment. After giving a survey of literature written on the meaning and definition of a speaking test assessment, two sections have been devoted to tackle the most important issues in this topic. Section one, which is the theoretical part of this paper, sheds light on the basic definitions of the term ‘speaking assessment’ which are, according to the researcher’s point of view, sufficient to cover the area of the study. This section based on applied linguistic theories and researches in order to enhance our understanding of the what is meant by «a speaking test assessment«In addition,it explains the most importan

... Show More
Publication Date
Tue Sep 27 2022
Journal Name
Al–bahith Al–a'alami
POLITICAL DEBATES AND THEIR ARTISTIC CONSTRUCTION IN IRAQI SATELLITE CHANNELS ( AN ANALYTICAL STUDY ) : (A research drawn from a Master Thesis)
...Show More Authors

The problem of research on the study of political debate programs in the Iraqi satellite channels, in the "People decide" program by Afaq channel and " electoral competition " by Fallujah channel), and its importance for the community and researchers in the scientific field, as new programs to enter the Iraqi media after we have been the world media a lot in this area at the academic and practical levels (The field), and seeks to find out what the technical construction of the programs of political debates in Iraqi satellite channels and methods of construction and methods of employment used by the technical elements in the presentation of the programs and The study adopted the surve

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Dec 14 2018
Journal Name
Iraqi National Journal Of Nursing Specialties
Monitoring Indicators for Maternal, Newborn and Child Health at Sub Primary Health Care Centers in Baghdad City: An Evaluative Study
...Show More Authors

Objectives: The study aims to evaluate the application of monitoring indicators for maternal, newborn and
child health through the evaluation of impact and coverage health indicators and to evaluate the usefulness of the
application of these indicators at sub primary health care centers in Baghdad City.
Methodology: A descriptive comparative design, which is using the evaluation approach, has been steered at
Sub Primary Health Centers of Baghdad City in order to evaluate the application; impact and coverage, and the
usefulness of monitoring indicators for maternal, newborn and child health from December 4th 2017 to April 29th
2018. A multistage, "non-probability" convenient, sample is selected for the present study. A t

... Show More
View Publication Preview PDF
Publication Date
Fri Mar 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
An empirical Evaluation of the effect of service encounter on customer voluntary behavior: Exploration study of (TBI) customers
...Show More Authors

Purpose: To determine the impact of service encounter in stimulating voluntary customer behaviors.

  • Approach / methodology: It was selected a sample of customers Bank Iraqi Trade (TBI) was (105) individual, using a questionnaire designed in the light of previous studies, was drafted scale and tested in the light of a group of statistical methods developed (reliability coefficient, reliability coefficient composite, convergence). Then test hypotheses through structural equation modeling.
  • Results: The behaviors and characteristics of the service provider in effect urged bank customers to perform voluntary extra, as the service environment service encounter

... Show More
View Publication Preview PDF
Crossref
Publication Date
Mon Mar 23 2020
Journal Name
Journal Of Engineering
Performance Analyses of 15 kW Grid-Tied Photo Voltaic Solar System Type under Baghdad city climate
...Show More Authors

The performance analyses of 15 kWp (kW peak) Grid -Tied solar PV system (that considered first of its type) implemented at the Training and Energy Research Center Subsidiary of Iraqi Ministry of Electricity in Baghdad city has been achieved. The system consists of 72 modules arranged in 6 strings were each string contains 12 modules connected in series to increase the voltage output while these strings connected in parallel to increase the current output. According to the observed duration, the reference daily yields, array daily yields and final daily yields of this system were (5.9, 4.56, 4.4) kWh/kWp/day respectively. The energy yield was 1585 kWh/kWp/year while the annual total solar irradiation received by solar array system was 198

... Show More
View Publication Preview PDF
Crossref (9)
Crossref
Publication Date
Fri Dec 01 2017
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Proposed Audit Program for Automated Clearing House System (ACH)
...Show More Authors

إن استخدام النظم الالكترونية في القطاع المصرفي وبالخصوص نظام مقاصة الصكوك الالكترونية (ACH) في عمليات التحويل الالكتروني للاموال بين المصارف تتضمن تحويلات مالية عالية القيمة  بين  المصارف المشاركة بهذا النظام, وان اي خلل قد يحدث بالنظام يؤدي الى حالات تلاعب في مقاصة الصكوك الالكترونية في المصارف المشاركة وبالتالي حدوث عملية اختلاس, ومن هذا المنطلق تبرز مشكلة البحث في اهمية توافر برنامج تدقيق مقترح ياخ

... Show More
View Publication
Crossref
Publication Date
Mon Dec 03 2018
Journal Name
Journal Of Engineering
Variable Structure Control Design for a Magnetic Levitation System
...Show More Authors

In this paper the variable structure control theory is utilized to derive a discontinuous controller to the magnetic levitation system. The magnetic levitation system model is considered uncertain, which subjected to the uncertainty in system parameters, also it is open-loop unstable and strongly nonlinear. The proposed variable structure control to magnetic levitation system is proved, and the area of attraction is determined. Additionally, the chattering, which induced due to the discontinuity in control law, is attenuated by using a non-smooth approximate. With this approximation the resulted controller is a continuous variable structure controller with a determined steady state error according to the selected control

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Tue Nov 01 2022
Journal Name
Indonesian Journal Of Electrical Engineering And Computer Science
Photovoltaic system DC series arc fault: a case study
...Show More Authors

<p>Photovoltaic (PV) systems are becoming increasingly popular; however, arc faults on the direct current (DC) side are becoming more widespread as a result of the effects of aging as well as the trend toward higher DC voltage levels, posing severe risk to human safety and system stability. The parallel arc faults present higher level of current as compared with the series arc faults, making it more difficult to spot the series arc. In this paper and for the aim of condition monitoring, the features of a DC series arc fault are analyzed by analysing the arc features, performing model’s simulation in PSCAD, and carrying out experimental studies. Various arc models are simulated and investigated; for low current arcs, the heur

... Show More
View Publication
Scopus (4)
Crossref (1)
Scopus Crossref
Publication Date
Fri Mar 31 2017
Journal Name
Journal Of Engineering
Rotating Ceramic Water Filter Discs System for Water Filtration
...Show More Authors

This work aimed to design, construct and operate a new laboratory scale water filtration system. This system was used to examine the efficiency of two ceramic filter discs as a medium for water filtration. These filters were made from two different ceramic mixtures of local red clay, sawdust, and water.  The filtration system was designed with two rotating interfered modules of these filters.  Rotating these modules generates shear force between water and the surfaces of filter discs of the filtration modules that works to reduce thickness of layer of rejected materials on the filters surfaces. Each module consists of seven filtration units and each unit consists of two ceramic filter discs.    The average measured hy

... Show More
View Publication Preview PDF
Publication Date
Sat Jan 01 2022
Journal Name
Proceedings Of International Conference On Computing And Communication Networks
Automatic Health Speech Prediction System Using Support Vector Machine
...Show More Authors

View Publication
Scopus (3)
Scopus Clarivate Crossref