Chlorinated volatile organic compounds (CVOCs) are toxic chemical entities emitted invariably from stationary thermal operations when a trace of chlorine is present. Replacing the high-temperature destruction operations of these compounds with catalytic oxidation has led to the formulation of various potent metal oxides catalysts; among them are ceria-based materials. Guided by recent experimental measurements, this study theoretically investigates the initial steps operating in the interactions of ceria surface CeO2(111) with three CVOC model compounds, namely chloroethene (CE), chloroethane (CA) and chlorobenzene (CB). We find that, the CeO2(111) surface mediates fission of the carbon–chlorine bonds in the CE, CA and CB molecules via modest reaction barriers. As a result of localization of excess electrons left behind after creation of oxygen vacancies, analogous fission over an oxygen vacant surface systematically necessitates lower energy barriers. Dehydrochlorination of CE and CA molecules preferentially proceeds via a dissociative addition route; however, subsequent desorption of vinyl and ethyl moieties requires less energy than surface assisted β C–H bond breakage. The profound stability of hydrocarbon species on the surface contributes to the observed deactivation of ceria at temperatures as low as 580 K under pyrolytic conditions. Adsorption of an oxygen molecule at an oxygen vacant site initiates decomposition of the adsorbed phenyl moiety. Likewise, adsorbed surface hydroxyl groups serve as the hydrogen source in the observed conversion of CB into benzene. A plausible mechanism for the formation of 1,4-dichlorobenzene incorporates abstraction of a para hydrogen in the CB molecule by an O− surface anion followed by chlorine transfer from the surface. Plotted conversion–temperature profiles via a simplified kinetic model against corresponding experimental profiles exhibit a reasonable agreement. The results from this study could be useful in the ongoing efforts to improve ceria's catalytic capacity for destroying CVOCs.
This study aims to the little impact of accounting financial performance (AFP) analysis on the money market in the Iraqi economy. Potentially limiting future market activity could be international risks and obstacles, which in turn could cause issues and crises (Shah & Jan, 2014; Bakhtiyarovich, 2020). The study concept was inspired by the recognition that there must be communication between the importance of the AFP analysis of the Iraqi securities market and the country’s financial and economic institutions. The sample of the study included ten Iraqi banks listed in the Iraq Stock Exchange (ISE) for the period 2010–2020. The three mathematical models included in the statistical analysis served as the basis for projectin
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This study assessed the effect of co-substitution of strontium (Sr) and magnesium (Mg) ions into the hydroxyapatite (HA) coating which was deposited on Ti–6Al–4V dental alloys by an electrochemical deposition process. The deposited layers were examined using energy-dispersive X-ray spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy and X-ray diffraction. The corrosion behavior of Ti–6Al–4V alloys in an artificial saliva environment was studied through potentiodynamic polarization technique and electrochemical impedance spectroscopy. The results indicated that the substituted Sr and Mg ions in HA improved the HA coating, where the protection efficiency percentage (PE%) for Ti
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The flat-headed borer, Capnodis tenebrionis (Linnaeus, 1760) , dispersed extensively in various geographical regions; it is extremely harmful and a dire threat to most stone fruit cultivars, and once the larva enters under the host tree crown, the infested host tree will gradually dry and eventually die. In this study, specimens were collected from several sites in Erbil province, Kurdistan Region- Iraq; then the fully grown larvae were selected for morphological study. In addition, clarification of morphological consequential and implication for most diagnostic characters were studied in all dissected parts. Scanning electron microscope (SEM) was used to further analyze the hidden features of the selected characteristics;
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This study aims to analyze the messages of a number of global news outlets on Twitter. In order to clarify the news outlets tactics of reporting, the subjects and focus during the crisis related to the spread of the Covid-19 virus. The study sample was chosen in a deliberate manner to provide descriptive results. Three news sites were selected: two of the most followed, professional and famous international news sites: New York Times and the Guardian, and one Arab news site: Al-Arabiya channel.
A total of 18,085 tweets were analyzed for the three accounts during the period from (1/3/2020) to (8/4/2020). A content analysis form was used to analyze the content of the news coverage. The results indicate an increase in th
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Background: Central serous chorioretinopathy (CSCR) is an idiopathic condition aggravated by exogenous or endogenous glucocorticoids. Vascular deregulation in the choroid is a new hypothesis regarding central serous chorioretinopathy occurrence. The inhibition of choroidal mineralocorticoid receptors has a great role in shortening the duration of CSCR by inhibiting choroidal vasodilatation and leak.
Objective: To assess the effect of oral spironolactone on subretinal fluid, central macular thickness and visual acuity in patients with acute CSCR compared to observation.
Subjects and Methods: a hospital based, randomized clinical trial carried out at outpatient clinic in Ibn-Alhaitham Teaching E
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Background: The appointment system is a common practice in primary health care clinics in developed countries. The patients and health care providers in the primary health care setting perceived the appointment system as an indicator of good quality service.
Objective: The aim of this study was to survey patients’ and health care providers’ attitudes towards the introduction of an appointment system and their satisfaction with the existing ‘walk-in’ system in the primary health care setting.
Subjects and Methods: A questionnaire survey was conducted included a convenient sample of 234 patients as well as 76 health care providers from two primary health care center
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This research involves study effect of chloride ions in concentration range (0.01 – 0.50 mol.dm-3) on the corrosion behavior of Al-Zn alloy in basic media of 1x10-3 mol.dm-3 NaOH at pH=11 and four different temperatures in the range (298-313 K). Cathodic and anodic Tafel slopes (bc &ba) and transfer coefficients (αc & αa) were calculated and the results interprets according to the variation of the rate – determining steps. The results also indicate that the chloride ions are bonded chemically in the interface as an initial step of formation of different mixed oxohydroxy – and chloro complexes. Polarization resistance (Rp) is calculates
... Show MoreSheep are considered as an important part of livestock in the worldwide, particularly in Iraq, as they provide meat, milk, leather, wool, and manure. The present study aim is isolation and identification of staphylococci, enteric bacteria and Pseudomonas spp. Totally, 115 samples were collected from sheep (100 samples were collected from the nasal cavity of local sheep suffering from respiratory infections, and 15 samples were collected from apparently healthy local sheep). All the samples were collected from seven flocks located in Abu Ghraib and Al-Radwaniyah, Baghdad governorate, Iraq. The samples were taken during the period from October 2020 to February 2021. Staphylococcus spp., Pseudomonas spp., and enteric bacteria were detected fi
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This study tries to examine a model involving human resources management practices, employees’ outcomes, governmental support, and organizational performance of small businesses in Malaysia. It was hypothesized that HRM practices will be positively related to the organizational performance (financial and operational), and that employees’ outcomes would serve as a mediator in the relationship between HRM practices and performance. Also it was hypothesized that the governmental support will be positively related to organizational performance. The statistical results on data gathered from a sample of 265 small manufacturing businesses will demonstrate the nature of relationships among the study variables. Theoretical and practical
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