Preferred Language
Articles
/
joe-823
Investigation of Optimum Heat Flux Profile Based on the Boiling Safety Factor
...Show More Authors

An experimental study is conducted to investigate the effect of heat flux distribution on the boiling safety factor of its cooling channel. The water is allowed to flow in a horizontal circular pipe whose outlet surface is subjected to different heat flux profiles. Four types of heat flux distribution profiles are used during experiments: (constant distribution profile, type a, triangle distribution profile with its maximum in channel center, type b, triangle distribution profile with its maximum in the channel inlet, type c, and triangle distribution profile with its maximum in the channel outlet, type d). The study is conducted using heat sources of (1000 and 2665W), water flow rates of (5, 7 and 9 lit/min). The water temperature at cooling channel inlet is kept constant at (25°C). Copper test section of (0.6 m) length (0.025m) inner diameter is used during the experiments. The electrical heater used for water heating is wrapped around the copper pipe covering (50 cm) of its length. Calibrated thermocouples are distributed along pipe surface at distances (0.1, 0.2, 0.3, 0.4 and 0.5 m) from pipe inlet to measure pipe surface temperature. The results shows that the heat source with heat flux profile of type (c) is the most reliable one from thermo-hydraulic safety point of view for both types of heat sources, as it ensures a maximum boiling safety factor (K) of (1.6, 1.7, 2) at water flow rates of (5, 7 and 9 lit/min) respectively based on maximum heat capacity of (2665 w), while the heat source with heat flux profile of type (d) which posses minimum boiling safety factors of (1, 1.2, 1.3) at water flow rates of (5, 7 and 9 lit/min) respectively based on same heat capacity value is the worst one from same point of view.

 

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Fri Mar 15 2019
Journal Name
Al-khwarizmi Engineering Journal
Theoretical Prediction of Optimum Chilled Water Distribution Configuration in Air Conditioning Terminal Unit
...Show More Authors

 The distribution of chilled water flow rate in terminal unit is a major factor used to evaluate the performance of central air conditioning unit. In this work, a theoretical chilled water distribution in the terminal units has been studied to predict the optimum heat performance of terminal unit. The central Air-conditioning unit model consists of cooling/ heating coil (three units), chilled water source (chiller), three-way and two-way valve with bypass, piping network, and pump. The term of optimization in terminal unit ingredient has two categories, the first is the uniform of the water flow rate representing in statically permanents standard deviation (minimum value) and the second category is the maximum heat transfer rate fro

... Show More
View Publication Preview PDF
Crossref
Publication Date
Thu Dec 23 2021
Journal Name
Iraqi Journal Of Science
Electrical Properties and Optimum Conditions of A Home-Made Magnetron Plasma Sputtering System
...Show More Authors

     In this work, the electrical properties and optimum conditions of the plasma sputtering system have been studied. The electrical properties such as Paschen's curve, current-voltage, current pressure relations, the strength of magnetic field as a function of inter-electrode distance, the influence of gas working pressure and argon-oxygen ratio on the electrical characterization were studied to determine the basic optimum condition of the system operation. the discharge current as a function of discharge voltage showed high discharge current at 2.5 cm.  These parameters represent the basic conditions to operate any plasma sputtering system which are the right behavior to build up and design the discharge an el

... Show More
View Publication Preview PDF
Scopus Crossref
Publication Date
Fri Dec 24 2021
Journal Name
Iraqi Journal Of Science
The Optimum Site Selection for Solar Energy Farms using AHP in GIS Environment, A Case Study of Iraq
...Show More Authors

    Recently, renewable energy (RE), such as solar energy, sources have proven their importance as an alternative source of fuel. The utilizing of solar energy can contribute to move the world towards relying on clean energy to curb global warming. However, the placement of solar farms is a major priority for planners as it is a critical factor in the succession energy project. This study combines one of the multi-criteria decision-making techniques Analytic Hierarchy Process (AHP) and Geographic Information System (GIS) to assess the suitability of land for establishing solar farms in Iraq. Numerous climatic, geomorphological, economic, and environmental criteria and some exclusionary constraints have been adopted in mode

... Show More
View Publication Preview PDF
Scopus (9)
Crossref (6)
Scopus Crossref
Publication Date
Thu Dec 31 2020
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
THE USE OF MICROENCAPSULATION TECHNOLOGY WITH COATING LAYER BY LAYER TO IMPROVE THE STABILITY OF THE Lactobacillus casei TOWARDS THE BILE SALTS AND TREATMENT HEAT.: THE USE OF MICROENCAPSULATION TECHNOLOGY WITH COATING LAYER BY LAYER TO IMPROVE THE STABILITY OF THE Lactobacillus casei TOWARDS THE BILE SALTS AND TREATMENT HEAT.
...Show More Authors

This study aimed to improve the microencapsulation technique using a type coating the encapsulation Layer by Layer, which provide the best protection for life Lactobacillus casei in the extrusion method and use the microencapsulation of materials of the protein concentrated by protein 80% and the coating with alginate and chitosan have the results showed the variation in the difference of the binding process encapsulation yield among the types of coating through. by studying of these the effect o stability of the bio probiotic free cell and the three types coated towards three different concentrations from bile salts 0, 0.3, 0.5 and 0.7% when the periods of time different of zero and two and three hours at incubation the recorded

... Show More
View Publication Preview PDF
Publication Date
Tue Nov 30 2021
Journal Name
Indian Journal Of Forensic Medicine & Toxicology
The role of vitamin D3 in improving lipid profile in type 2 diabetes patients with
...Show More Authors

Publication Date
Tue Feb 12 2019
Journal Name
Iraqi Journal Of Physics
Investigation of the dielectric properties of Sn – doped PMMA/PVA blends
...Show More Authors

Blends of Polymethyl methacrylate (PMMA)/polyvinyl alcohol (PVA) doped with 2% weight percentage of Sn were prepared with different blend ratios using casting technique. The measurements of A.C conductivity σa.c within the frequency range (25kHz – 5MHz) of undoped and Sn doped PMMA/PVA blends obeyed the relationship σ= Aws were the value of s within the range 0 > s > 1. The results showed that σa.c increases with the increase of frequency. The exponent s showed preceding increase with the increase of PVA content for PMMA/PVA blends doped with Sn. The dielectric constant, dielectric loss, A.C electrical conductivity are varied with the concentration of PVA in the blend and frequency of applied electrical field.

View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Thu Feb 01 2018
Journal Name
Journal Of Engineering
Experimental Investigation of the Electro Co-deposition of (Zinc-Nickel) Alloy
...Show More Authors

An experimental investigation has been carried out for zinc-nickel (Zn-Ni) electro-deposition using the constant applied current technique. Weight difference approach method was used to determine the cathode current efficiency and deposit thickness. Also, the influence effect of current density on the deposition process, solderability, and porosity of the plating layer in microelectronic applications were examined. The bath temperature effect on nickel composition and the form of the contract was studied using Scanning Electron Microscope (SEM). Moreover, elemental nature of the deposition was analyzed by Energy Dispersive X-Ray (EDX).     

It has been found that the best bath temperature

... Show More
View Publication Preview PDF
Publication Date
Sun Apr 26 2020
Journal Name
Iraqi Journal Of Science
Assessment of Levels of Metabolic Hormones and Lipid Profile in Growth Hormone Deficient Patients
...Show More Authors

Abstract

The current study aims to evaluate levels of metabolic hormones and lipid profile in a sample of growth hormone (GH) deficient patients. Seventy five GH deficient patients and twenty healthy subjects used as control group have been participated in this study during their attendance to the National Diabetic Center for Treatment and Research/Al-Mustansiriya University. The studied subjects’ ages were with a range (3-15 years). Blood samples were collected from the studied subjects to determine levels of basal GH, GH2 and GH3 after 1 hr and 1/30 hr provocation with clonidine, respectively; insulin like growth factor (IGF-1); levels of metabolic hormones [thyroid profile: triiodo

... Show More
View Publication Preview PDF
Scopus (4)
Crossref (1)
Scopus Crossref
Publication Date
Fri Nov 01 2019
Journal Name
Journal Of Engineering
Analysis of Shell and Double Concentric Tube Heat Exchanger Using CFD Application
...Show More Authors

This study focuses on CFD analysis in the field of the shell and double concentric tube heat exchanger. A commercial CFD package was used to resolve the flow and temperature fields inside the shell and tubes of the heat exchanger used. Simulations by CFD are performed for the single shell and double concentric tube.

This heat exchanger included 16 tubes and 20 baffles. The shell had a length of 1.18 m and its diameter was 220 mm. Solid Works 2014, ANSYS 15.0 software was used to analyze the fields of flow and temperature inside the shell and the tubes. The RNG k-ε model was used and it provided good results. Coarse and fine meshes were investigated, showing that aspect ratio has no significant effect. 14 million

... Show More
View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Mon Oct 24 2022
Journal Name
Energies
Double-Slope Solar Still Productivity Based on the Number of Rubber Scraper Motions
...Show More Authors

In low-latitude areas less than 10° in latitude angle, the solar radiation that goes into the solar still increases as the cover slope approaches the latitude angle. However, the amount of water that is condensed and then falls toward the solar-still basin is also increased in this case. Consequently, the solar yield still is significantly decreased, and the accuracy of the prediction method is affected. This reduction in the yield and the accuracy of the prediction method is inversely proportional to the time in which the condensed water stays on the inner side of the condensing cover without collection because more drops will fall down into the basin of the solar-still. Different numbers of scraper motions per hour (NSM), that is

... Show More
View Publication
Scopus (1)
Crossref (1)
Scopus Clarivate Crossref