In the present work the clathrate hydrate dissociation enthalpies of refrigerant R134a+ water system, and R134a + water + salt system were determined. The heat of dissociation of three types of aqueous salts solutions of NaCl, KBr and NaF at three concentrations (0.09, 0.17and 0.26) mol·kg−1 for each salt type, were enthalpy measured. The Clapeyron equation was used tocalculate heat of dissociation of experimental data for binary and ternary system.In order to find the effect of compressibility factor on heat dissociation enthalpy, the study was conducted by using equation of state proposed by Peng and Robinson Stryjek-Vera (PRSV). The obtained results of dissociation enthalpy for binary system were (143.8) kJ.mol-1 without gas compressibility factor (z) and (136.08) kJ.mol-1 with z where the variation between two values was (5.3%). For ternary system (R134a+ water +NaCl) at three concentrations of this salt, the calculated values were in the range of (146.7 - 154.1) kJ.mol-1without z and (138.02-145.14) kJ.mol-1with z where the variation rang between two values was (5.8-5.7) %. The other two types of salts given similar results within (0.886 - 0.129) % deviation rang about NaCl results without z and (0.818-0.149) % deviation rang with z values.
Organizations nowadays, whether public or private organizations, productive or service (such as banks), face major challenges as a result of rapid and continuous changes, and in front of these challenges traditional management operations and tools become unable to make the organization able to work, which makes it imperative for these organizations to follow the methods and management practices, including the proposed knowledge risk management and strategic direction so that it can elevate its actions at the level of developments in reality, in the sense that these organizations and in the light of environmental developments to characterize their strategic direction as an intellectual approach characterized by mo
... Show MoreA twisted-fin array as an innovative structure for intensifying the charging response of a phase-change material (PCM) within a shell-and-tube storage system is introduced in this work. A three-dimensional model describing the thermal management with charging phase change process in PCM was developed and numerically analyzed by the enthalpy-porosity method using commercial CFD software. Efficacy of the proposed structure of fins for performing better heat communication between the active heating surface and the adjacent layers of PCM was verified via comparing with conventional longitudinal fins within the same design limitations of fin material and volume usage. Optimization of the fin geometric parameters including the pitch, numb
... Show MoreThe research utilizes data produced by the Local Urban Management Directorate in Najaf and the imagery data from the Landsat 9 satellite, after being processed by the GIS tool. The research follows a descriptive and analytical approach; we integrated the Markov chain analysis and the cellular automation approach to predict transformations in city structure as a result of changes in land utilization. The research also aims to identify approaches to detect post-classification transformations in order to determine changes in land utilization. To predict the future land utilization in the city of Kufa, and to evaluate data accuracy, we used the Kappa Indicator to determine the potential applicability of the probability matrix that resulted from
... Show MorePlatelet‐rich fibrin (PRF) has been widely used in regenerative dentistry due to many growth factors produced. Periostin, a matricellular protein, is a reliable marker for tissue regeneration. Periostin is part of the cellular matrix and regulates bone homeostasis. This study aims to explore the efficacy of PRF in improvement of the clinical periodontal parameters as an adjunct to the scaling and root planing and to evaluate periostin level in gingival crevicular fluid (GCF) at baseline, 1‐ and 3‐month recall visits. Fourteen periodontitis patients who met the inclusion criteria were recruited in this study. Two contralateral periodontal pockets with 4–6 mm in depth in each patient were sel
The current research aims to identify the effectiveness of a computerized program in developing mathematical skills among the first cycle students in basic education schools in the Sultanate of Oman. The two researchers used the quasi-experimental approach on an intentional sample consisting of (40) male and female students at Al Kawakeb School for Basic Education (1-4). Two of the basic fourth-grade classes and then randomly distributing them into two groups, one is experimental (20) male and female students who followed the computerized interactive program, and the other is (20) male and female students followed the traditional way. On the other hand, its reliability has reached (0.81), and the results of the research have concluded th
... Show MoreAntimicrobial resistance (AMR) is a serious challenge for infectious disease prevention and treatment, according to the World Health Organization. It is a worldwide problem caused primarily by inappropriate and insufficient therapy, misuse of antimicrobials without physician supervision, unnecessary hospital readmissions, and other factors. AMR has several consequences, including increased medical costs and mortality. The present study aimed to evaluate imipenem resistance in gram-negative bacteria in Central Pediatric Teaching Hospital in Baghdad, Iraq, and determine this bacteria resistance in different samples. Initially, a total of 100 different samples were collected from child patients from October 1, 2020, to August 31, 2021. Each is
... Show MoreIt is a common Knowledge that adverbs in Turkish languages can modify verbs, adjectives, nouns or other adverbs. Moreover, adverbs can determine the meanings of nouns and verbs in a sentence as far as time, place, manner, quantity and interrogative are concerned. The present study debates adverbs’ functions in Namiq Kamal’s play Vatan yahut Silistre.
The study sheds light on the author’s use of the adverbs to describe the required theatrical actions of the play and to convey his reflections and thoughts easily to the auidence. One of the main hindrances encountered in conducting the study is the shortage of the upto date academic resources necessary for
... Show Morehe current research aims to analyze the relationship and the level of influence of labor relations in reducing the cases of job withdrawal in private colleges in Baghdad. (265) individuals from department heads, university professors, and teaching staff in (7) private colleges located in the capital, Baghdad, and based on the Stephen Thompson equation for small samples, the sample size was determined by (157) teachers, and the questionnaire was adopted as a main tool for collecting data and information After ensuring the validity and reliability of its contents, and to test the relationship of influence, correlation and interaction between the research variables, two main hypotheses were formulated from which (5) sub-hypotheses eman
... Show MoreA theoretical analysis of mixing in the secondary combustion chamber of ramjet is presented. Theoretical investigations were initiated to insight into the flow field of the mixing zone of the ramjet combustor and a computer program to calculate axisymmetric, reacting and inert flow was developed. The mathematical model of the mixing zone of ramjet comprises differential equations for: continuity, momentum, stagnation enthalpy, concentration, turbulence energy and its dissipation rate. The simultaneous solution of these equations by means of a finite-difference solution algorithm yields the values of the variable at all internal grid nodes.
The results showed that increasing air mass flow (0.32 to 0.64 kg/s) increases the development o