The University of Nizwa was established in 2002 by the Decree of Sultan Qaboos as the first non-profit university in the Sultanate of Oman; it remains the only institution of its kind in the nation. Upon the satisfaction of all requirements set forth by the Ministry of Higher Education and the Higher Education Council, the University of Nizwa was granted legal status by ministerial decision No. 1/2004 on January 3, 2004. On October 16, 2004, the University of Nizwa opened the doors to its inaugural class of 1,200 students, 88% of whom were Omani women. The current campus is located near the base of the famous Jabal al-Akhdhar in Birkat al-Mouz, 20 km NW of Nizwa. The construction of a new campus, located near the new Farq-Hail highwa began in March 2010. Still unaccredited with lower ranking, the university is currently in the final stage of institutional accreditation in accordance with the academic standards established by the Oman Academic Accreditation Authority. Wikipedia.
Comment on the article “Effect of CaO addition on preparation of ferrotitanium from ilmenite by electrochemical reduction in CaCl2–NaCl molten salt” by L. Xiong, Y.X. Hua, C.Y. Xu, J. Li, Y. Li, Q.B. Zhang, Z.R. Zhou, Y.D. Zhang, J.J. Ru
Schwandt C.,The University of Nizwa
Journal of Alloys and Compounds | Year: 2017
A recent publication by Xiong et al.  presents a study on the molten salt electrochemical reduction of ilmenite, FeTiO3, to ferrotitanium, FeTi. The study follows the concept of the FFC-Cambridge process, using the FeTiO3 as the cathode in a molten chloride salt as the electrolyte and graphite as the anode, such that FeTi is formed as the metallic product at the cathode. The interpretation that the Authors offer for their various experimental observations is based entirely on the chemical thermodynamics of the perceived overall cell reactions. The interpretation completely ignores both the electrochemical kinetics of the cathode reaction and the ionic transfer properties of the electrolyte. Herein, it is demonstrated that this approach leads to erroneous conclusions, and a more comprehensive interpretation is given instead. © 2017 Elsevier B.V.
Thomas S.,The University of Nizwa
Nutrition Research | Year: 2012
Resveratrol is a naturally occurring polyphenolic compound. Numerous animal studies have been reported on its wide-ranging beneficial effects in the biological system including diabetes mellitus (DM). We hypothesized, therefore, that oral supplementation of resveratrol would improve the glycemic control and the associated risk factors in patients with type 2 diabetes mellitus (T2DM). The present clinical study was therefore carried out to test the hypothesis. Sixty-two patients with T2DM were enrolled from Government Headquarters Hospital, Ootacamund, India, in a prospective, open-label, randomized, controlled trial. Patients were randomized into control and intervention groups. The control group received only oral hypoglycemic agents, whereas the intervention group received resveratrol (250 mg/d) along with their oral hypoglycemic agents for a period of 3 months. Hemoglobin A1c, lipid profile, urea nitrogen, creatinine, and protein were measured at the baseline and at the end of 3 months. The results reveal that supplementation of resveratrol for 3 months significantly improves the mean hemoglobin A1c (means ± SD, 9.99 ± 1.50 vs 9.65 ± 1.54; P < .05), systolic blood pressure (mean ± SD, 139.71 ± 16.10 vs 127.92 ± 15.37; P < .05), total cholesterol (mean ± SD, 4.70 ± 0.90 vs 4.33 ± 0.76; P < .05), and total protein (mean ± SD, 75.6 ± 4.6 vs 72.3 ± 6.2; P < .05) in T2DM. No significant changes in body weight and high-density lipoprotein and low-density lipoprotein cholesterols were observed. Oral supplementation of resveratrol is thus found to be effective in improving glycemic control and may possibly provide a potential adjuvant for the treatment and management of diabetes. © 2012 Elsevier Inc.
Hussain H.,University of Paderborn |
Hussain H.,The University of Nizwa |
Green I.R.,Stellenbosch University |
Ahmed I.,Karlsruhe Institute of Technology
Chemical Reviews | Year: 2013
The various synthetic methods discussed in this review reveal that Oxone is a versatile reagent used in organic synthesis. Oxone is a cheap commercially available oxidant that easily oxidizes numerous functional groups. It is an efficient single oxygen-atom donor since it contains a nonsymmetrical O-O bond which is heterolytically cleaved during the oxidation cycle. It is an inexpensive reagent ($0.02-0.04/g), which compares favorably with hydrogen peroxide and bleach. Its byproducts do not pose an immediate threat to aquatic life upon disposal, and unlike chromium trioxide and bleach, it does not emit pungent vapors or pose a serious inhalation risk. The aqueous components of an organic Oxone reaction are oxidizing and acidic and should thus be quenched with sodium bisulfite followed by neutralization with sodium bicarbonate, thereby resulting in formation of a mixture of nonhazardous sulfate salts in water. These features make Oxone attractive for large-scale applications. Uses of other oxidizing agents lack the desired ingredients to attract the interest of industry because of tedious purification processes from their deoxygenated counterparts. The dioxirane (generated from reaction between Oxone and a ketone) epoxidation offers many advantages over traditional methods of epoxidation. Oxone is about one-half as expensive as m-chloroperoxybenzoic acid (mCPBA) and converted to KHSO4. KHSO4 during the reaction, while being relatively acidic, can easily be neutralized with dilute NaOH solution to produce nontoxic Na2SO4. Furthermore, the reaction conditions require the use of relatively nontoxic organic solvents plus water. Another advantage of dioxirane epoxidation is that acetone is recycled in the reaction, which means all of the extra oxygen in Oxone is incorporated into the respective alkenes. Dioxirane is also capable of oxidizing very unreactive olefins, and thus, isolation of some relatively unstable epoxides produced from glycals is possible. This represents a major advantage over the Sharpless and mCPBA protocols, which only epoxidize electron-rich olefins and allylic or homoallylic alcohols. These latter reagents also require a directing group. One drawback that dioxirane does have is the fact that it can also oxidize very reactive heteroatoms, hydroxyl groups, and unactivated C-H bonds during the epoxidation procedure. Oxone does have some disadvantages: (a) it is insoluble in organic solvents, (b) buffering is needed due to its acidity, and (c) it sometimes bleaches the metal catalysts and donor ligands during oxidation reactions. To overcome the need for aqueous conditions, some authors have used ionic liquids as solvent, and additionally, several tetraalkylammonium salts of Oxone have been reported. It has been found that when the cation in Oxone (i.e., K+) is changed to, e.g., n-Bu4N+, the oxidant also shows higher solubility in organic solvents, especially in dichloromethane. Tactical utilization of Oxone in synthetic plans is that it may replace tedious organic transformations with simpler routes. One other drawback which needs to be mentioned is that a relatively large excess of Oxone may be required in some reactions to consume all of the starting material. However, militating against this is that Oxone can be reused when it is in stoichiometric excess. Owing to the discovery of a variety of novel applications, Oxone is becoming an increasingly important reagent in synthetic organic chemistry. We hope that this review may act as a catalyst in boosting applications of Oxone in organic synthesis.
Ezzat M.A.,Alexandria University |
Karamany A.S.E.,The University of Nizwa
Zeitschrift fur Angewandte Mathematik und Physik | Year: 2011
A new mathematical model of two-temperature magneto-thermoelasticity is constructed where the fractional order heat conduction law is considered. The state space approach is adopted for the solution of one-dimensional application for a perfect conducting half-space of elastic material with heat sources distribution in the presence of a transverse magnetic field. The Laplace-transform technique is used. A numerical method is employed for the inversion of the Laplace transforms. According to the numerical results and its graphs, conclusions about the new theory are given. Some comparisons are shown in figures to estimate the effects of the temperature discrepancy and the fractional order parameter on all the studied fields. © 2011 Springer Basel AG.
Nasir Uddin M.,University of Malaya |
Daud W.M.A.W.,University of Malaya |
Abbas H.F.,The University of Nizwa
Renewable and Sustainable Energy Reviews | Year: 2013
The objective of this paper is to develop more favorable hydrogen energy that holds the potential to realize zero-carbon emissions, thereby negating concerns over global warming and promoting an outlook free of the dependency on fossil fuels. Pyrolytic gas has much H2, CO2, CO, and light hydrocarbons, such as CH4, C2H6, etc., as non-condensable gases (NCGs), which offer the potential for use in industrial, power and transportation fields. This paper emphasizes the influence of biomass characteristics and compositions, moisture content, particle size, heating rate, temperature, reactor system, and carrier gases and catalysts on the production of hydrogen and NCG. The composition of the NCGs varies widely depending on the properties of the biomass and moisture content, which play key roles on the mole fraction of hydrogen in the final products. A small particle size is favorable in the chemically controlled pyrolysis process for hydrogen production, while the reformation of NCGs into H2 via a shift reaction is significant in increasing the total hydrogen formation in the presence of catalysts. A great deal of effort has been directed towards the system carrier gas in terms of hydrogen production, because it enhances the secondary decomposition reaction. Thermo-chemical and biological processes for hydrogen production from sustainable energy sources are also reviewed. In order to predict the maximum hydrogen formation of a given feedstock, the extent to which the processes are dependent on the heating rate and the temperature of the biomass in the reactor is investigated. It is our belief that this is a crucial assessment in establishing a link and developing a learning strategy between networks of biomass to hydrogen transformation-related activities and in assessing the current economic status of this pyrolysis process in achieving the ultimate hydrogen energy source. © 2013 Elsevier Ltd.
Ashik U.P.M.,University of Malaya |
Wan Daud W.M.A.,University of Malaya |
Abbas H.F.,The University of Nizwa
Renewable and Sustainable Energy Reviews | Year: 2015
Thermocatalytic decomposition of methane (TCD) is a fully green single step technology for producing hydrogen and nano-carbon. This review studying all development in laboratory-scale research on TCD, especially the recent advances like co-feeding effect and catalyst regeneration for augmenting the productivity of the whole process. Although a great success on the laboratory-scale has been fulfilled, TCD for greenhouse gas (GHG) free hydrogen production is still in its infancy. The need for commercialization of TCD is greater than ever in the present situation of huge GHG emission. TCD usually examined over various kind of catalysts, such as monometallic, bimetallic, trimetallic, combination of metal-metal oxide, carbonaceous and/or metal doped carbon catalysts. Deactivation of catalysts is the prime drawback found in TCD process. Catalyst regeneration and co-feeding of methane with other hydrocarbon are the two solutions put forwarded in accordance to overcome deactivation hurdle. Higher amount of co-feed hydrocarbon in situ produce more amount of highly active carbonaceous deposits which assist further methane decomposition to produce additional hydrogen to a great extent. The methane conversion rate increases with increase in the temperature and decreases with the flow rate in the co-feeding process in a similar manner as observed in normal TCD. The presence of co-components in the post-reaction stream is a key challenge tackled in the co-feeding and regeneration. Hence, this review hypothesizing the integration of hydrogen separation membrane in to methane decomposition reactor for online hydrogen separation. © 2014 Elsevier Ltd. All rights reserved.
Jarndal A.,The University of Nizwa
International Journal of RF and Microwave Computer-Aided Engineering | Year: 2013
An accurate equivalent circuit large-signal model (ECLSM) for AlGaN-GaN high electron mobility transistor (HEMT) is presented. The model is derived from a distributed small-signal model that efficiently describes the physics of the device. A genetic neural-network-based model for the gate and drain currents and charges is presented along with its parameters extraction procedure. This model is embedded in the ECLSM, which is then implemented in CAD software and validated by pulsed and continuous large-signal measurements of on-wafer 8 × 125-μm GaN on SiC substrate HEMT. Pulsed IV simulations show that the model can efficiently describe the bias dependency of trapping and self-heating effects. Single- and two-tone simulation results show that the model can accurately predict the output power and its harmonics and the associated intermodulation distortion (IMD) under different input-power and bias conditions. © 2012 Wiley Periodicals, Inc.
Al-Hemyari Z.A.,The University of Nizwa
Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability | Year: 2010
The Weibull failure model is considered in this paper. Some testimators are proposed of the scale parameter (β) and of the reliability function (R(t)) using life-testing data when a prior value about the unknown parameter (β) is available. The expressions for the bias, mean squared error and relative efficiency are obtained and compared with existing estimators.
Usman M.,University of Malaya |
Wan Daud W.M.A.,University of Malaya |
Abbas H.F.,The University of Nizwa
Renewable and Sustainable Energy Reviews | Year: 2015
This review will explore the influences of the active metal, support, promoter, preparation methods, calcination temperature, reducing environment, particle size and reactor choice on catalytic activity and carbon deposition for the dry reforming of methane. Bimetallic (Ni-Pt, Ni-Rh, Ni-Ce, Ni-Mo, Ni-Co) and monometallic (Ni) catalysts are preferred for dry reforming compared to noble metals (Rh, Ru and Pt) due to their low-cost. Investigation of support materials indicated that ceria-zirconia mixtures, ZrO2 with alkali metals (Mg2+, Ca2+, Y2+) addition, MgO, SBA-15, ZSM-5, CeO2, BaTiO3 and Ca0.8Sr0.2TiO3 showed improved catalytic activities and decreased carbon deposition. The modifying effects of cerium (Ce), magnesium (Mg) and yttrium (Y) were significant for dry reforming of methane. MgO, CeO2 and La2O3 promoters for metal catalysts supported on mesoporous materials had the highest catalyst stability among all the other promoters. Preparation methods played an important role in the synthesis of smaller particle size and higher dispersion of active metals. Calcination temperature and treatment duration imparted significant changes to the morphology of catalysts as evident by XRD, TPR and XPS. Catalyst reduction in different environments (H2, He, H2/He, O2/He, H2-N2 and CH4/O2) indicated that probably the mixture of reducing agents will lead to enhanced catalytic activities. Smaller particle size (<15 nm) had a significant influence on the suppression of carbon deposition and catalytic activity. Fluidized bed reactor exhibited the highest activity and stability, lower carbon deposition and higher conversion compared to a fixed-bed reactor. Moreover, membrane reactor, solar reactor, high-pressure reactor and microreactor were also investigated with specific features such as: pure H2 production, detailed reaction information with enhanced safety, higher pressure applications and dry reforming reaction with/without catalyst under sunlight. The study of parameters would improve the understanding of various preparation and reaction conditions leading to various catalytic activities. © 2015 Elsevier Ltd. All rights reserved.
El-Karamany A.S.,The University of Nizwa
Journal of Thermal Stresses | Year: 2011
The reciprocal theorem is proved and the convolutional variational principle is established for the two-temperature linear anisotropic and inhomogeneous micropolar thermoviscoelastic solid. A proof, based on variational principle of a uniqueness theorem with no restrictions imposed on the relaxation or thermal conductivity tensors except symmetry conditions, is given. The theorems for classical dynamic coupled micropolar-thermoviscoelasticity theory result as special case when the two temperatures coincides. Copyright © Taylor & Francis Group, LLC.