Time resolved spectroscopic investigation of SiD2 + D2: kinetic study

Silylenes (silanediyls) have made an important impact on organosilicon chemistry even if it is of more recent foundation than carbenes in organic chemistry and much less complete. These species are highly reactive intermediates. They play a central role in the chemical vapour deposition (CVD) of various silicon-containing thin films which have a technological importance in microelectronics as well as in the dry etching processes of silicon wafers. Spectroscopic methods have been developed to observe these species, a necessary pre-requisite to their direct monitoring. In this work, deuterated phenylsilane precursor, PhSiD3 was chosen for SiD2 because its analogue phenylsilane, PhSiH3 proved to be a good precursor for SiH2 and the high quality decay signals observed revealed that SiD2 be readily detected from PhSiD3 and that if other decomposition pathways (e.g. PhSiD + D2) are occurring, they do not effect measurements of the rate constants for SiD2. The absorption spectrum of SiD2 formed from the flash photolysis of a mixture of PhSiD3 and SF6 at 193nm were found in the region 17384-17391 cm-1 with strong band at 17387.07 cm-1. This single rotational line of pQ1 was chosen to monitor SiD2 removal. Time-resolved studies of SiD2 have been carried out to obtain rate constants for its bimolecular reactions with D2. The reactions were studied over the pressure range 5-100 Torr (in SF6 bath gas) at four temperatures in the range 298-498K. Single decay from 10 photolysis laser shots were averaged and found to give reasonable first-order kinetics fits. Second order kinetics were obtained by pressure dependence of the pseudo first order decay constants and substance D2 pressures within experimental error. The reaction was found to be weakly pressure dependent at all temperatures, consistent with a third-body mediated association process. In addition, SiH2+ H2 reaction is approximately ca. 60% faster than SiD2+D2 reaction. Theoretical extrapolations (using Lindemann-Hinshelwood model and Rice, Ramsperger, Kassel and Marcus (RRKM) theory) were also carried out and obtained data fitted the Arrhenius equations

The role of paper and process technologies for mechanisms and image quality in digital electrophotography

Image quality and the mechanisms involved in digital dry toner electrophotography are influenced by the interactions between the printing machine, toner and paper in the last two steps where the paper is involved, i.e., in transferring the developed image toner to the paper, and in fusing the image to be fixed permanently on the paper surface. This study discusses the role of paper in these two steps in different technologies and its effect on the printing mechanisms and image quality. The control of optical, electrostatic and mass and heat transfer phenomena in the printing process are affected by the unevenness of the properties of paper due to its heterogeneous structure and its sensitivity to humidity conditions and printing process parameters. In this research, a set of experiments was conducted to understand the electrostatic behaviour of paper in toner transfer and thermal behaviour in toner fusing. The results show that not only image quality is affected by the variability of paper properties, but also the mechanisms of toner transfer and fusing. Accordingly, the research suggests that the paper should be included as part of the printing mechanism, performance (printability and runnability), and image quality. Consequently, if there is a change in paper properties due to a change in ambient conditions or the use of another grade for a specific application, the process parameters can be adjusted to compensate for these changes in order to meet the requirements for image quality. It was found that the variability in image quality in terms of colours (the requirement for different toner layers), grey scale (halftone structure) and the location of the image in the xy-plane is affected when rendered through the electrophotographic process. The fast mechanical speed in printing machine direction drives the toner transfer and fusing mechanisms differently from the cross machine direction. As a result, a certain image element such as a line will have different quality in these two printing directions, or if the line is placed in the length or width direction of the page. The conclusion was that the electrophotographic process should be designed to reduce or even to neglect the effect of paper when printing a high-quality colour image in a high-speed process. This can be achieved by eliminating the contact with paper from the image side in both transfer and fusing by adopting the technologies of toner jumping transfer and non-contact flash fusing. These technologies have special requirements for chemical and physical toner properties, such as modification for equal absorbance of the flash radiation by CMYK colours, a suitable melting viscosity and surface energy, and a small and narrow toner particle size and shape distribution to unify the charge-to-mass ratio of the toner, which is important for transfer quality and efficiency. To ensure high print quality for different applications, some of the transfer and fusing parameters need to be automatically adjusted according to substrate specific properties and levels of image coverage

Ultrasonic Technique in Treating Wastewater by Electrocoagulation

Electrocoagulation Treatment can be considered as a favorable tool for the removal of many pollutants of various forms of wastewater. These pollutants may include the removal of colloidal, the breaking-up of emulsions and heavy metals. This process consists of the disintegration of the anodes (usually iron or aluminum), exciting the creation of coagulant mixtures in wastewater. That will aid to coagulate contaminants and generate bubbles in favor of mixing and elimination of solids suspension by flotation. Recently, the arrangement of using this technique with other treatment tools has turned out to be an interesting subject leading to an improvement in the removal efficiency of the treatment. In this study, a combined treatment of electrocoagulation and ultrasound has been applied to treat three most common wastewaters in oil industry. The ultrasound-electrocoagulation removal efficiencies for the removal of oil, suspended bentonite and zinc have been evaluated here. In this work, a synthetic wastewater would be treated using electrocoagulation technique to reduce turbidity caused by pollutants. This process has been done in a batch reactor equipped with aluminum/iron electrodes with and without agitation. The effects of one of the most important parameter, i.e. applied voltage on turbidity have been studied. In addition, the effect of using ultrasonic has been also evaluated. It was found when ultrasonic used with electrocoagulation, the turbidity increased for suspended bentonite and oily wastewaters and an improvement in removal efficiency for the heavy metals pollutants. The results were compared and discussed

Corrosion and Hydrogen Attack of Pipelines in Oil and Gas Fields

Conditions for hydrogen sulfide and carbon dioxide corrosion of pipeline in oil,gas, and gas-condensate fields are discussed. Various factors are shown to affect theCO2 and H2S corrosion rate of steel in oil and gas field media. Protective propertiesof sulfide film as a function of partial pressures of H2S and CO2, pH and temperaturesare studied

Nano Ferrites as Corrosion Inhibitors for Carbon Steel in Local Iraqi Bentonite Mud

Corrosion processes are accountable for serious losses in the oil industry. Although organic and inorganic materials and mixed materials inhibitors have been used for a long time to control or reduce corrosion. Using nano-materials as inhibitors has gained an increasing applications role because of their exceptional properties. Nano materials are good corrosion inhibitors because they possess many advantages such as high efficiency of inhibition, low cost, minimum toxicity and effortless production. This work examines the use of nano-materials as inhibitors to prevent corrosion of carbon steel in drilling mud. Anti-corrosion properties of zinc and nickel ferrite nano materials (ZnFe2O4, Zn0.6Ni0.4Fe2O4) have been investigated over carbon steel in local Iraqi bentonite mud as a source of the corrosion. It has been found that under the given conditions, ferrites act as efficient corrosion inhibitors of carbon steel

The Impact of Materials and Maintenance Considerations during the Design Stage of Public Buildings in Oman

The purpose of this study is to describe the experiences of architects and civil engineers in the Sultanate of Oman regarding building maintenance during the design of public buildings. This exploratory and descriptive study used a qualitative approach, drawing data from focus groups in particular, to develop a rich and in-depth description of the designers’ building maintenance experiences. Structured interviews were conducted with 15 participants from architecture and civil engineering fields, from which, the interviewees shared the viewpoint that maintenance functions entirely separate from the design and construction process itself, but that it is, in fact, an integral part of the design process and post-occupancy stage. The designer should plan for sufficient maintenance for the whole building life cycle. However, some elements are more difficult to maintain in Oman than in other regions such as roofs, facades and the substructure of buildings. The results showed that salt is the most challenging environmental factor that could cause building defects. This was followed by solar heat, moisture from below ground and, lastly, rain. Most of these defects occurred during the buildings’ post-occupancy phase and were related to inappropriate or poor design. The results also suggested that deficiencies caused by thermal expansion came in the form of cracks, followed by paint decay, dampness, and staining

The Influence of Microstructure on the Corrosion Rate of Carbon Steels

This paper presents the influence of carbon steel microstructure on the corrosion rates. Four types of microstructures have obtained by quenching and tempering and iso-thermal annealing. These microstructures are: banded ferrite/pearlite microstructure, fine ferrite/pearlite microstructure, coarse ferrite/pearlite microstructure and tempered martensite microstructure. General corrosion and localized corrosion (penetration rates) were determined via mass loss and optical microscopy. The different microstructures of steels investigated in this paper revealed corrosion rate variations of 0.8– 3.2 mm y-1 and 3.3–6.4 - mm y-1 for the general and localized forms, respectively. The corrosion stability of the various microstructures may arise from variations of phases within the steel. A banded ferrite/pearlite microstructures have worse general corrosion properties, while tempered martensite worse microstructures have localized pitting corrosion properties. Coarse ferrite/pearlite microstructures have better localized pitting corrosion resistances compared to others investigated microstructures This paper has demonstrated that, microstructure is an important consideration when selecting carbon steel for an industrial corrosion resistance application

Interprofessional Competency Framework for Health Service Managers in Oman: An e-Delphi Study

Objectives: This study aimed to develop the required interprofessional competencies for health service managers in Oman. Methods: Experts (n = 20) were selected based on their years’ experience, position, fluency in English (both verbal and written), and who had completed higher education at either masters or doctorate levels in the relevant field. The data collection consisted of three rounds. Responses were collected and extracted from a web-based designed survey and subsequently analyzed. Results: Experts agreed on the nine interprofessional domains and 41 competencies based on the inclusion of means (M) ≥ 4.4, an interquartile distribution (IQD) ≤ 1.25, and > 80.0% agreement. Findings revealed that there were levels of agreement (90.0% to 95.0%) among the experts in the nine interprofessional competency domains namely: resilience (M = 4.7, IQD = 0.40), research leverage (M = 4.7, IQD = 0.60), interprofessional ethics (M = 4.7, IQD = 0.80), quality improvement (M = 4.7, IQD = 0.80), information technology (M = 4.6, IQD = 0.80), leadership (M = 4.5, IQD = 1.00), management skills (M = 4.5, IQD = 0.80), communication (M = 4.5, IQD = 1.00), and team dynamics (M = 4.5, IQD = 1.00). Conclusions: The development of interprofessional competencies for health service managers is an impetus to strengthen the human resources capabilities, sustain a high level of quality patient outcomes, and to achieve the Ministry of Health’s Health Vision 2050

Efficient and sustainable remediation of refinery wastewater using electrocoagulation and advanced oxidation techniques

Effluent wastewater from industrial processes needs to be properly treated before being discharged into the environment. Conventional procedures for handling this wastewater can be problematic due to the presence of toxic elements, time constraints, and complexity. However, a new electrochemical procedure has been developed as an effective method for remediation. In a recent study, refinery wastewater was successfully treated using an electrochemical technique combined with ultrasonic irradiation and photocatalysis. The study found that electrocoagulation, which uses cheap and recyclable metal electrodes, was a simple, efficient, practical, and cost-effective way to handle refinery wastewater. Various parameters were investigated, including electrode metals, operating time, applied voltage, pH, inter-electrode gap, and temperature. The aim was to determine the optimal configuration for pollutant removal. The study also focused on the synergistic effects of combining electrocoagulation and photocatalysis to improve the efficiency of contaminant removal in oily wastewater. By integrating these two treatment technologies, the researchers aimed to enhance pollutant removal rates, energy efficiency, and overall system performance. The research provided valuable insights into the feasibility, optimization parameters, and applicability of the electrocoagulation-photocatalysis process for remediating organic contaminants in oily wastewater industrial effluents. The results showed that electrocoagulation, especially when combined with ultrasonic irradiation and TiO2 photocatalysis, was highly effective in pollutant removal within a short timeframe. These findings support the implementation of this procedure for remediating most industrial wastewater.In conclusion, the study contributes to the development of more effective and sustainable water treatment strategies. The electrocoagulation-photocatalysis process shows promise in addressing the remediation of organic contaminants in oily wastewater from industrial processes

Sulphide pollutants elimination and degradation in petroleum wastewater by ozonation process

An efficient and robust chemical oxidation process using an OZ-3G ozone generator was developed and investigated to degrade and reduce sulphide toxicity in petrochemical wastewater. Different concentrations of sulphide in synthetic wastewater were prepared and evaluated using the Spectrophotometric technique. The values of Chemical Oxygen Demand (COD) and pH were also studied. The obtained results demonstrated that 100 minutes of ozone treatment removed 97.4 % for 40 mg/L concentration. The pH was decreased gradually with the increase along the time of oxidation. Based on the ozone method's significant results, ozonation can be considered a potential candidate method for wastewater treatment in petroleum refineries