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HEAT TRANSFER ENHANCEMENT USING PASSIVE TECHNIQUE: REVIEW

Preserving and saving energy have never been more important, thus the requirement for more effective and efficient heat exchangers has never been more important. However, in order to pave the way for the proposal of a truly efficient technique, there is a need to understand the shortcomings and strengths of various aspects of heat transfer techniques. This review aims to systematically identify these characteristics two of the most popular passive heat transfer techniques: nanofluids and helically coiled tubes. The review indicated that nanoparticles improve thermal conductivity of base fluid and that the nanoparticle size, as well as the concentrations of the nanoparticles plays a major role in the effectiveness of the nanofluids. Regarding the helically coiled tubes, it was discovered that the use of a coiled tube produces secondary flows, which ultimately improves the heat transfer enhancement. The third part of the review focused on microchannels and microtubes. This is mainly due to the growing need and requirement of smaller and more compact thermal cooling systems. Thus, ultimately the result of the review indicates that a combination of all these three techniques can lead to a compact and minimized heat exchanger that uses the benefits obtained from both nanofluids and helically coiled tubes in order to improve the heat transfer rate of the thermal systems.

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Publication Date
Sun Oct 22 2023
Journal Name
Iraqi Journal Of Science
A Novel Semi Automated On-Line Determination of Oxonium Ion Via Precipitation Reaction Using a New Mode of Attenuated Measurement of Incident Light (0 – 180o) by AYAH 5SX4-ST-5D Solar CFI Analyser.

Strong acids were determined via the precipitation reaction of loaded copper (II) ion on strong cation exchange resin which in turn reacts with potassium hyxacyano ferrate (II). The attenuation effect of formed precipitate Cu2 [Fe (CN) 6] on (0 -180o) incident LED light was measurement via homemade AYAH 5SX4-ST-5D solar CFI analyser. Optimum parameters were 0.005M.L-1 [Fe(CN)6]-4 , flow rate of 2.4 mL.min-1 , sample volume 204 μL , sample purge time of 64 seconds was chosen, and 1.6 V for light intensity. A liner calibration graph of 0.005 -0.2 M.L-1 were obtains for HCl, HNO3, HCLO4 and H2SO4, with a linearity (r2 %) 96 -97 % and L.O.D based on gradual dilution of lowest concentration in calibration graph was 37.19 μg for HCl, 64.273

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Publication Date
Fri Apr 12 2019
Journal Name
Journal Of Economics And Administrative Sciences
Measuring the speed of response of the exported quantity of crude oil to the increase in its prices using the model Impulse Response Functions (IRF) (Iraq case study) for the period (1978-2017)

Abstract

     Oil is considered a commodity and is still an important and prominent role in drawing and shaping the Iraqi economic scene. The revenues generated from the export of oil are considered the main source of the general budget in cash flows.  

     Since the revenues consist of quantity and price and the latter is an external factor which is difficult to predict, The effect of any commodity on its price, which is proven in the theory of micro-economic, but it is observed through the research that the response is slow, which means not to take advantage of the rise in prices, by increasing the quantity exported, the result of several facto

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Publication Date
Mon Feb 25 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Planning and implementation of the audit process by using the styles of time management and its impact on the quality of the audit process: Applied Research in the Federal Board of Supreme Audit

Witnessing the global arena many changes in the political, economic, social, scientific and technological have left their mark on the world as a whole, these changes require necessarily Advancement of the profession of auditing, and improve their performance, especially after the mixer skepticism the health of approach and the method followed by a check in the major audit firms global view as for the external audit of an active role in providing services to members of the community in various sectors, were to be provide these services to the highest level of quality.To ensure the quality of the audit process to be a proper planning is based on a scientific basis to be the substrate a strong underlying different audit works, and if planni

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Publication Date
Tue Aug 01 2023
Journal Name
Baghdad Science Journal
Spectrophotometric Determination of Micro Amount of Chromium (III) Using Sodium 4-((4,5-diphenyl-imidazol-2-yl)diazenyl)-3-hydroxynaphthalene-1-sulfonate in the Presence of Surfactant, Study of Thermodynamic Functions and Their Analytical Applications

          Using sodium4-((4,5-diphenyl-imidazol-2-yl)diazenyl)-3-hydroxynaphthalene-1-sulfonate (SDPIHN) as a chromogenic reagent in presence of non-ionic surfactant (Triton x-100) to estimate the chromium(III)  ion if the wavelength of this reagent 463 nm to form a dark greenish-brown complex in wavelength 586 nm at pH=10,the complex was stable for longer than 24 hours. Beer's low, molar absorptivity 0.244×104L.mol-1.cm-1, and Sandal's sensitivity 0.021 µg/cm2 are all observed in the concentration range 1-11 µg/mL. The limits of detection (LOD) and limit of quantification (LOQ), respectively, were 0.117 µg/mL and 0.385µg/mL. (mole ratio technique, job's method) were employed to

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Publication Date
Mon Jan 01 2018
Journal Name
Al–bahith Al–a'alami
Using Social Media sites by the Iraqi women and the Achieved The Use of Iraqi Women of Social Networking Sites and the Satisfactions Generated from Them.: A Survey Study of the City of Baghdad

The problem of this research lies in the fact that there is a lack of accurate scientific perceptions about the size of the use of Iraqi women’s social networking sites and the motives behind this use and the expectations generated by them.
The goals of the research are as follows:
1- Determine the extent of Iraqi women’s use of social networking sites (Facebook, YouTube, twitter, and Instagram).
2- Investigative the motives behind the use of social networking sites by Iraqi women.
3- Detecting the repercussions of Iraqi women’s use of social networking sites (Facebook, you tube, twitter, and Instagram).
The research is classified as a descriptive one. The researchers use the survey methodology. The research commu

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Publication Date
Tue Nov 19 2024
Journal Name
Al.qadisiya Journal For The Sciences Of Physical Education
The Influence of Using Special Exercises with Weights to Develop Moments of Force to Some of the Striking Shoulder and Arm Muscles and Accuracy of the Skill of the Smash and Rectum in Volleyball

This research is an attempt to develop exercise with weights to strengthen some of the striking muscles in the shoulder and arm and to develop the accuracy of the smash and rectum skills. The importance of this paper lies in the study of moments of force to achieve the ability to control muscular work and to explore the impact of physical and skill exercises with weights to develop moments of force for some muscles. The experimental method on a sample of players, selected according to the intentional method, including ( 9) advanced players representing Air Force Club participating in the Premier League for season 2011-2012. It is concluded that the exercises proposed have their effective impact on developing the variables of moments force f

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Publication Date
Mon May 15 2023
Journal Name
Iraqi Journal Of Science
Determination of hydrogen peroxide in some local pharmaceutical disinfectants by continuous flow injection analysis via turbidimetric (T180o) and scattered light effect at two opposite positions (2N90o ) using Ayah 4SW-3D-T180o -2N90o -Solar - CFI Analyse

An indirectly method is used to determine hydrogen peroxide. The method based on oxidation of chromium (III) ion by hydrogen peroxide in basic medium to form chromate ion which react with barium (II) ion to produce a yellow precipitate (BaCrO4). Under the optimum established conditions, the linear range of 0.50-25.00 mmol L-1 along with correlation coefficient (r) of 0.9992, Limit of detection (LOD) 0.68 μg / 100 μL, precision expressed as relative standard deviation for six replication measurements at 5.0 mmol.L-1 H2O2 of less than 2% were obtained for hydrogen peroxide. The developed method was successfully applied for the estimation of H2O2 in three pharmaceuticals preparation of different companies using continuous flow injection o

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Publication Date
Tue Jan 01 2013
Journal Name
Journal Of Geochemical Exploration
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Publication Date
Sat Dec 30 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Molecular Cloning of large DNA Fragments of The Sal t Tolerant wild Tetra ploid bermudagrass Cynodon Dactylon L. Using A Bacteriophage Cloning Vector 2. Ligation a nd in vitro packaging of The Recombinant Phage DNA Molecules

This  paper represent  the second  step  i n  a molecular clon i ng program ai ming to clone large DNA  fi·agmen ts of the sal t tolerant  bermudagrass (Cyrwdon  dactylon  L.)  DNA  usi ng  the  bacteriophage  (EM13L3) as    a vector.

In th is  work, a yield of about  I 00  g bacteriophage  DNA  per one  liter culture.was obtained  with.a  purity ranging between (1.7-1.8). The vector JJNA  v.as  completely   double   digested   with  the  restriction   enzymes llamHI   and  EcoRI,  followed  by  pu

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Publication Date
Sat Dec 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
Comparison of the method of partial least squares and the algorithm of singular values decomposion to estimate the parameters of the logistic regression model in the case of the problem of linear multiplicity by using the simulation

The logistic regression model is an important statistical model showing the relationship between the binary variable and the explanatory variables.                                                        The large number of explanations that are usually used to illustrate the response led to the emergence of the problem of linear multiplicity between the explanatory variables that make estimating the parameters of the model not accurate.    

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