Catalytic utilization of carbon dioxide as renewable feedstock for production of chemicals and fuels

The utilization of CO2 as a renewable feedstock for producing commodity chemicals and fuels is an interesting challenge to explore new concepts and opportunities in catalysis and industrial chemistry. This sustainable approach not only leads to production of useful chemicals, but also has the potential to mitigate anthropogenic CO2 emissions to the atmosphere. CO2 itself is a sustainable and inexhaustibly available carbon source, however, it is inextricably linked to its inherent inertness. It is a thermodynamically stable molecule (ΔGf = -394.01 kJ.mol-1) with high oxidation state, hence, reactions of CO2 must be combined with a high-energy reactant to gain a thermodynamic driving force. It has been shown that catalytic reaction is the best strategy to address this challenge. Although several processes for production of urea, methanol, and salicylic acid have been developed through CO2 utilization, many of them rely on extremes of temperature and pressure to work. Owing to the growing energy demand and increasing atmospheric carbon dioxide (CO2) concentration, it is desirable to identify effective hydrocarbon transformation reactions in tandem with CO2 conversion. Research on direct transformation of light paraffins -such as methane, ethane and propane into light olefins -such as ethylene and propylene and aromatics has gained considerable importance recently because of its potential large-scale implementation for production of fine chemicals, pharmaceuticals, plastics and liquid fuels from C1-C4 hydrocarbons in the shale gas. The catalytic conversion of propane into propylene in the presence of CO2 as a soft oxidant opens opportunities to simultaneously reduce CO2 to CO and convert paraffin into value-added products --Abstract, page iv

RHIZOSPHERE-COMPETENT ACTINOBACTERIAL ISOLATES WITH ACC DEAMINASE ACTIVITY ALLEVIATE SALT STRESS IN TOMATO PLANTS IN THE UAE

Tomato (Solanum lycopersicum) is one of the most popular vegetables in the world, including the United Arab Emirates (UAE). Salinity is a global menace to plant growth and development, causing significant economic losses to tomato and other crop plants. It is well-known that 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (ACCD) can increase plant tolerance to environmental stresses. This can be attributed to the increased activity of the enzyme ACCD, which breaks down ACC [the immediate precursor of ethylene (ET)] to ammonia and α-ketobutyrate, to lower the overproduction of ET levels in planta and to reduce the damages caused by salt stress. Consequently, the application of beneficial actinobacteria was assessed to alleviate the destructive effects of salt stress on tomato plants. The main objective of this project was to isolate and apply ACCD-producing actinobacteria with increased salt tolerance to relieve any stress on tomato plants cultivated under high salt conditions. Four hundred ninety-one actinobacteria were isolated from the rhizosphere soils of Sweihan area in Abu Dhabi-UAE. In vitro screening demonstrated that three actinobacterial isolates produced ACCD, while tolerating up to 8% NaCl. In the greenhouse, the most promising ACCD-producing isolate (referred to as +ACCD isolate) significantly (

Enhanced Oil Recovery Using Seismic Excitation

The major factor in increasing residual oil recovery depends on controlling interfacial forces inside the reservoir. In a water wet system, a thin water film covers the matrix material and water forms a continuous phase. When the oil saturation drops below some critical value, it forms a droplets and become dispersed in the water phase. To pass the dispersed droplets through pore throat constrictions, large forces are required. Such large force can be provided by water injection. However, since water is the continuous phase, it bypasses the oil droplets instead of pushing them through the constrictions. A numerical study was performed in order to understand the effect of the seismic waves on the oil droplet trapped in capillary pore throat. The results show that periodic variation of pressure at the pore throat has a nudging effect on the trapped oil drops and in the process it squeezes them through the pore throat constriction

Analyzing the Impact of Significant Factors on Motivation and Accountability of Employees in the Supply Chain of Organization

Undoubtedly, all efforts and behaviors are based on motives and goals. Motives and goals are two of the main internal and external factors that make people reach the destination to work. This article seeks to provide factors that influence the motivation and accountability of employees in the supply chain of organization. The results of the research showed that paying attention to employees' motivational factors and their needs and paying attention to individual differences of each employee is one of the most important factors. Which can be achieved in the productivity of human resources and one of the essential conditions for achieving the goal in every way is to provoke and motivate and respond to the people who do it. Factors like meritocracy, awarding rewards to better services, preventing and disrupting individual choices are one of the most important motivations and responses

Performance Evaluation of Mobility Models over UDP Traffic Pattern for MANET Using NS-2

                                                                                                                  تعرض الدراسة الحالية دراسة وتقييم نماذج محاكاة شبكة الـ MANET على نمط حركة UDP لتحديد تأثيرات نمط الحركة هذا على نماذج التنقل في MANET والتي يتم تنفيذها في محاكي الشبكة NS-2.35 وفقًا لمقاييس الأداء المختلفة (الإنتاجية، نسبة الحزم المنقولة من المصدر الى الهدف  (PDF)، تحميل التوجيه الطبيعي (NRL) و زمن التأخير من نهاية إلى نهاية (AED)) مع مختلف المعلمات مثل السرعات المختلفة، ومناطق بيئة مختلفة، وعدد مختلف من العقد، ومعدلات مرور مختلفة، ومصادر مختلفة للحركة، اختلاف وقت التوقف وأوقات محاكاة مختلفة. نستخدم بروتوكول التوجيه AODV ونموذج نقطة الطريق العشوائية (RWP)، نموذج مجموعة نقاط المرجعي (RPGM)، نموذج غاوس ماركوف (GMM) ونموذج شبكة مانهاتن (MGM) ونماذج التنقل مع نمط الحركة CBR. تُظهر نتائج المحاكاة أن أداء بروتوكول التوجيه مع نموذج نقطة مجموعة المراجع RPGM هو الأفضل مقارنةً بنماذج التحرك الأخرى.  The current study presents the simulative study and evaluation of MANET mobility models over UDP traffic pattern to determine the effects of this traffic pattern on mobility models in MANET which is implemented in NS-2.35 according to various performance metri (Throughput, AED (Average End-2-end Delay), drop packets, NRL (Normalize Routing Load) and PDF (Packet Delivery Fraction)) with various parameters such as different velocities, different environment areas, different number of nodes,  different traffic rates, different traffic sources, different pause times and different simulation times .  A routing protocol.…was exploited AODV(Adhoc On demand Distance Vector) and RWP (Random Waypoint), GMM (Gauss Markov Model), RPGM (Reference Point Group Model) and MGM (Manhattan Grid Model) mobility models above CBR traffic sources. The results of Reference Point Group Model simulation illuminate that routing protocol performance is best with RPG mobility model than other models

BIM as Evaluation Tool for Existing Building Energy and Quantities Takeoff

Information technology and its application have resulted in enormous development in the construction industry during the last decade. The main reason behind this evolution was the incorporation of Building Information Modeling (BIM) to be an inefficient construction approach. BIM is now globally considered to be the tool of transforming the construction process to new era. It is also considered as a good tool for the whole project lifecycle. The aim of the present study is to clarify how BIM can be used in after project construction within uncertainty and risky environment such as document losses and unrecorded change orders. Interviews with project team, project site photography, collecting the available schemes and documents were the approaches used in this work to re-build the projects models. The results obtained from this work show that the knowledge and expectations of BIM within existing building have an admirable achievements for construction industry. Furthermore, BIM approach used in this work made more progress in the implementation of BIM as a rehabilitation and renovation tool in civil projects. The conclusions from this study reflect high correlation between the quantities take off with what as-built constructed, more than the traditional approach. The glamorous lessons derived from BIM implementation for the case study is; working with a model in which all project team feel comfortable and harmonic, will ensure enough resources to make the model updated and ought to lead to a minimum conflict within the model or what traditionally called  “project documents”

Behavior of Post-Tensioned Concrete Girders Subject to Partially Strand Damage and Strengthened by NSM-CFRP Composites

Studies on the flexural behavior of post-tensioned beams subjected to strand damage and strengthened with near-surface mounted (NSM) technique using carbon fiber-reinforced polymer (CFRP) are limited and fail to examine the effect of CFRP laminates on strand strain and strengthening efficiency systematically. Furthermore, a design approach for UPC structures in existing design guidelines for FRP strengthening techniques is lacking. Hence, the behavior of post-tensioned beams strengthened with NSM-CFRP laminates after partial strand damage is investigated in this study. The testing program consists of seven post-tensioned beams strengthened by NSM-CFRP laminates with three partial strand damage ratios (14.3% symmetrical damage, 14.3% asymmetric damage, and 28.6% symmetrical damage). The experimental results showed that the use of CFRP laminates significantly increases the flexural capacity by up to 17.4 to 20.4%, corresponding to a strand damage ratio of 14.3 and 28.6%, respectively, enhances the stiffness, and reduces strand strain by up to 15.8 to 22.2%. However, the flexural stiffness of strengthened beams during serviceability phases is critical as strand damage ratios increase. Additionally, semi-empirical equations were proposed to predict the actual strain of unbonded strands whilst considering the effects of CFRP laminates. The suggested equations provide accurate predictions with little variance. Doi: 10.28991/CEJ-2022-08-07-013 Full Text: PD

Uni and Simplex Optimization for the Spectrophotometric Determination of Erythromycin ethylsuccinate Drug via Charge-Transfer Complex Formation

Charge transfer complex formation method has been applied for the spectrophotometric determination of erythromycin ethylsuccinate, in bulk sample and dosage form. The method was accurate, simple, rapid, inexpensive and sensitive depending on the formed charge- transfer complex between cited drug and, 2,3-Dichloro-5,6-dicyano-p- benzoquinone (DDQ) as a chromogenic reagent. The formed complex shows absorbance maxima at 587 nm against reagent blank. The calibration graph is linear in the ranges of (10 - 110) µg.mL-1 with detection limit of 0.351µg.mL-1. The results show the absence of interferences from the excipients on the determination of the drug. Therefore the proposed method has been successfully applied for the determination of erythromycin ethylsuccinate in pharmaceutical preparations. Keywords: Simplex, Spectrophotometric, Erythromycin ethylsuccinate , Charge- transfer

Evaluating Windows Vista user account security

In the current Windows version (Vista), as in all previous versions, creating a user account without setting a password is possible. For a personal PC this might be without too much risk, although it is not recommended, even by Microsoft itself. However, for business computers it is necessary to restrict access to the computers, starting with defining a different password for every user account. For the earlier versions of Windows, a lot of resources can be found giving advice how to construct passwords of user accounts. In some extent they contain remarks concerning the suitability of their solution for Windows Vista. But all these resources are not very precise about what kind of passwords the user must use. To assess the protection of passwords, it is very useful to know how effective the widely available applications for cracking passwords. This research analyzes, in which way an attacker is able to obtain the password of a Windows Vista PC. During this research the physical access to the PC is needed. This research shows that password consists of 8 characters with small letter characters and numbers can easily be cracked if it has know usual combinations. Whereas a Dictionary Attack will probably not find unusual combinations. Adding captel letter characters will make the process harder as there are several more combinations, so it will take longer time but is still feasible. Taking into account special characters it will probably take too long time and even most Dictionary Attacks will fail. For rainbow tables the size of the table has to be considered. If it is not too big, even these small passwords cannot be cracked. For longer passwords probably the simplest ones, small letter characters and numbers, can be cracked only. In this case brute force takes too long time in most cases and a dictionary will contain only a few words this long and even the rainbow tables become too large for normal use. They can only be successful if enough limitations are known and the overall size of the table can be limited

Improving the Performance of Constructed Wetland Microbial Fuel Cell (CW- MFC) for Wastewater Treatment and Electricity Generation

ركزت هذه الدراسة على إداء المسطحات المائية الصناعية المدمجة مع خلية الوقود المايكروبية في معالجة المياه الملوثة وتوليد الطاقة الكهربائية. في هذه الدراسة تم استخدام نوعين من الاقطاب; الفولاذ المقاوم للصدأ و كَرافيت. تم تنظيم الاقطاب الكهربائية في ثلاثة مجاميع. في التنظيم الأول القطبين الموجب والسالب كانا عبارة عن صفيحة من الكَرافيت، في التنظيم الثاني القطب السالب كان عبارة عن صفيحة مشبكة من الفولاذ المقاوم للصدأ أما القطب الموجب فكان عبارة عن صفيحتين من الفولاذ المقاوم للصدأ. أما في التنظيم الثالث فالقطب السالب كان عبارة عن صفيحة مشبكة من الفولاذ المقاوم للصدأ في حين القطب الموجب كان عبارة عن صفيحة من الكَرافيت. ان أعلى طاقة تم الحصول عليها هي (9 Mw/m3) كانت من التنظيم الثالث. بعد مرور 10 أيام من بدء التشغيل، كانت افضل نسبة لإزالة المتطلب الكيمائي للأوكسجين (COD) كانت 70% وقد تم الحصول عليها من التنظيم الثاني. إن تأثير درجة الحرارة قد تمت دراسته ايضاً، حيث تم إختبار توليد الطاقة الكهربائية من التنظيم الثالث في درجات حرارة 30،35 و40 درجة مئوية وإن أفضل نتيجة ((80 Ma/m3 كانت في درجة حرارة 40 درجة مئوية. في هذه الأنظمة الثلاثة تم السماح للطحالب بالنمو حتى تزود هذه الأنظمة بالأوكسجين اللازم لعملية الاختزال.The current study deals with the performance of constructed wetland (CW) incorporating a microbial fuel cell (MFC) for wastewater treatment and electricity generation. The whole unit is referred to as CW-MFC. This technique involves two treatments; the first is an aerobic treatment which occurs in the upper layer of the system (cathode section) and the second is anaerobic biological treatment in the lower layer of the system (anode section). Two types of electrode material were tested; stainless steel and graphite. Three configurations for electrodes arrangement CW-MFC were used. In the first unit of CW-MFC, the anode was graphite plate (GPa) and cathode was also graphite plate (GPc), in the second CW-MFC unit, the anode was stainless steel mesh (SSMa) and the cathode was a couple of stainless steel plain (SSPc). The anode in the third CW-MFC unit was stainless steel mesh (SSMa) and the cathode was graphite plate (GPc). It was found that the maximum performance for electricity generation (9 mW/m3) was obtained in the unit with stainless steel mesh as anode and graphite plate as cathode. After 10 days of operation, the best result for COD removal (70%) was obtained in the unit with stainless steel mesh as anode and stainless steel plain as cathode. The effect of temperature was also investigated. The performance of unit operation for electricity generation was tested at three values of temperature; 30, 35 and 40oC. The best result was obtained at 40oC, at which the current density obtained was 80 mA/m3. A culture of Algae could grow in the unit in order to supply the cathodic region with oxygen