New approach to steady-state and dynamic nonlinear modelling of laminated salient-pole alternator systems

A complete mathematical model for a generator system consisting of an isolated laminated salient-pole alternator, exciter and prime mover is presented, with emphasis on the inherent electromagnetic nonlinearities in the alternator and its exciter. An equivalent circuit, representing the rotor circuits accurately, has been adopted to model the al ternator in the dqo reference frame. A computer program has been developed to calculate the unsaturated parameters of the model using the machine design data. A new approach has been developed to account for the electromagnetic saturation effects on the model reactances. Consequently new saturation factors, based on the machine design particulars have been deri ved. The advantages of these saturation factors, compared with conventional factors, are that both mutual saturation effects between the main and leakage fluxes, and between the direct- and quadratureaxis fluxes are considered. A mathematical nonlinear model, utilising the new saturation factors, is presented for a system containing an isolated laminated salientpole alternator and a direct thyristor static exciter. A digital computer program has been developed to simulate the system. The predicted results, for some steady state and dynamic candi tions, showgood agreement with test results and clear improvement over those obtained if saturation is either neglected or considered using the conventional saturation factors. At high saturation levels, the conventional method of calculating the machine transformer voltages, using static saturated reactances, gives unacceptable errors. A method for calculating these voltages correctly, in models utilising the currents as state space variables, is presented using new derived dynamic saturated reactances. This dynamic reactance concept is presented in a generalised form so that it can be applied to any machine with different saturation factors. The previous mathematical model of the alternator system has been modified according to the dynamic reactance concept, and the computer program has been developed accordingly. The predicted results confirm the need to apply this concept especially to dynamic conditions characterised by high saturation levels. To extend the analysis to a wider range of loading conditions, the alternator has been modelled in the abc reference frame. The unsaturated, static and dynamic saturated reactances of the machine in this reference frame have been obtained using conventional dqo-abc transformation techniques. Starting from the fundamental machine relations, a new set of equations, in the phase reference frame, has been derived employing the new dynamic reactance concept. A comprehensive system consisting of an isolated laminated salientpole alternator, brushless exciter, thyristor divert automatic voltage regulator and a diesel prime mover has been studied. Both the alternator and the exciter have been modelled in the abc frame to comply with the nature of rectifier loading associated with the exci ter. A complete steady state and dynamic mathematical model is presented where the t~r technique has been applied to the dynamic variable topology of the system electrical circuits. The model presented covers all the possible modes of operation associated with the exciter rotating bridge rectifier circuit. A digital computer program has been developed to simUlate the system. The predicted results obtained using the new set of saturation factors in conjunction with the dynamic reactance concept show good agreement with the test results. The study presented confirms the validity of the mathematical models developed for the alternator systems. Also, it supports the metlxxi by which the electromagnetic nonlinearity has been accounted for

Binding Affinity and Interaction of SARS-CoV-2 Epitopes with Major Histocompatibility Complex

SARS CoV-2 has been affecting the world since 2019. It caused 245 million cases of infection and around 5 million deaths worldwide. The most important strategies for the development of vaccines against SARS-CoV-2 are inactivated or weakened virus, replicating or non-replicating viral vector-based approaches, DNA, RNA, virus particle like approaches and epitope-based approaches. The epitope-based approach is rapid, accurate, cost-effective, and reliable against pathogens. By presenting epitopes (antigen peptides) on antigen-presenting cells (APCs), the major histocompatibility complex (MHC), also recognized as the human leukocyte antigen (HLA) system in humans, plays an essential role in triggering T-cell immune responses. The focus of this study is to identify the binding motif of the epitopes generated from the structural proteins such as spike, membrane, and nucleocapsid of SARS CoV-2 with the MHC. Two HLAs including HLA-DQ and HLA-A*30 were considered for this study. The three-dimensional structure of the epitopes was modelled by the PEP-Fold server. All the three-dimensional models of the epitopes have extended alpha-helix structures with short-coiled C-termini. The interactions of these epitopes with the MHC complexes were noticed. Using a molecular docking approach, the binding affinity and non-bonding interactions between the MHC and epitope were measured and identified by PATCH-DOCK and FIRE-DOCK. In HLA-DQ, the epitopes showed binding affinities ranging from -36.58 to -82.31 kcal/mol, whereas in HLA-A*30 all epitopes showed comparatively lower binding affinities, ranging from -34.90 to -59.78 kcal/mol. Some of the epitopes were accurately bound to the residues in the peptide-binding grooves of HLA complex while some were in the vicinity of the binding site. Our results can provide more understanding of HLA supertypes and pave the way for SARS-CoV-2 epitope screening and vaccine development based on the binding motifs of different supertypes

Enhancing Voters’ Satisfaction towards Political Marketing through Party Characteristics (Policy, Issue) and Candidate Image

This research examines the influence of party characteristics and candidate image on voters’ satisfaction of political marketing industry in the context of Jordan. The researcher employed partial least squares - structural equation modeling (PLS-SEM) technique to test the influences resulted from party characteristics and candidate image on voters’ satisfaction. Moreover, to determine the relationship between each variable. The results show that the proposed model of party characteristics and candidate image explains voters’ satisfaction well. Accordingly, this paper discusses these factors for enhancing voters’ satisfaction by party policy, party issue, and candidate image. Keywords: party policy, party issue, candidate image, voters’ satisfaction

Effecting Of Candidate Image On Post-Voting Behaviour, Mediating Roll Of Voters’ Satisfaction In Jordanian Parliament Election Using Hirschman Theory

The post-purchasing behavior and customer behavior have received a great attention in marketing research since a long time ago, whereas academic literature in the political marketing and voting behavior is still sparse, particularly factors that affecting on post-voting behavior. Therefore, this paper attempts to fill this gap by examining the relationship between candidate image and post-voting behavior (exit, voice, and loyalty). It also seeks to reviews the mediation role of voters' satisfaction in primary relationship to address the inconsistent findings in the previous studies. Keywords: Candidate image, voters’ satisfaction, post-voting behavior (Exit, Voice, Loyalty)

Impact of the Water Content in the Therapeutic Deep Eutectic Solvents

Deep eutectic solvent(s) (DES) are the new generation of greener and more sustainable solvents, formulated by the complex of hydrogen bond in the molecules. The solvents allow us to achieve a significantly lower freezing point compared to its components, an affordable formulation and a technology that is typically formulated to improve the bioavailability of a drug. In this research project, we synthesized an ibuprofen-menthol based therapeutic deep eutectic solvent and investigated how water content affects the structure and dynamics of the solvent. For synthesizing the ibuprofen-menthol DES, 2.0629 g of Ibuprofen and 4.6881 g of menthol were placed in a small breaker to achieve a 1:3 molar ratio. The mixer was covered by parafilm paper and was then heated on a hot plate at temperature of 50 ºC with 600 rpm for 30 minutes until a clear liquid was observed. In the infrared spectrum of the DES, a strong C-H stretching is noticed at 2800-2950 cm-1, OH bonds at 3345.57 cm-1 which involves in hydrogen bonding, and a less strong peak for the C=O stretching is detected at 1708.41 cm-1. Raman spectroscopy results showed that 10% and 20 % of water do not interrupt the ibuprofen-menthol’s Raman shift compared to the pure DES, however, significant change is observed while 30% and 40 % water were added to the system

HYDRODESULFURIZATION OF THIOPHENE OVER COMO/ AL2O3 CATALYST USING FIXED- AND FLUIDIZED-BED REACTORS

The present work reports a direct experimental comparison of the catalytic hydrodesulfurization of thiophene over Co-Mo/Al2O3 in fixed- and fluidized-bed reactors under the same conditions. An experimental pilot plant scale was constructed in the laboratories of chemical engineering department, Baghdad University; fixed-bed unit (2.54 cm diameter, and 60cm length) and fluidized-bed unit (diameter of 2.54 cm and 40 cm long with a separation zone of 30 cm long and 12.7 cm diameter). The affecting variables studied in the two systems were reaction temperature of (308 – 460) oC, Liquid hourly space velocity of (2 – 5) hr-1, and catalyst particle size of (0.075-0.5) mm. It was found in both operations that the conversion increases with increasing of reaction temperature, slightly decreases with increasing of liquid hourly space velocity and not affected by particle size. Also a kinetic analysis was performed for thiophene hydrodesulfurization reaction in fixed bed reactor and the results indicate that the reaction kinetics are not affected by pore and film diffusion limitations. The results of the comparison between the two reactors indicate that a low conversion was obtained in a fluidized bed than in fixed bed over the range of conditions studied. The lower conversion can be attributed to the gas that bypasses the bed in the form of bubbles or channels

DEWAXING OF DISTILLATE OIL FRACTION (400- 500 ºC) USING UREA

De-waxing of lubricating oil distillate (400-500 ºC) by using urea was investigated in the present study. Lubricating oil distillate produced by vacuum distillation and refined by furfural extraction was taken from Al-Daura refinery. This oil distillate has a pour point of 34 ºC. Two solvents were used to dilute the oil distillate, these are methyl isobutyl ketone and methylene chloride. The operating conditions of the urea adduct formation with n-paraffins in the presence of methyl isobutyl ketone were studied in details, these are solvent to oil volume ratio within the range of 0 to 2, mixer speed 0 to 2000 rpm, urea to wax weight ratio 0 to 6.3, time of adduction 0 to 71 min and temperature 30-70 ºC). Pour point of de-waxed oil and yield of wax produced were determined to show the effect of these operating conditions. The most favorable operating conditions were solvent to oil volume ratio of 1, mixer speed of 1500 rpm, urea to wax weight ratio of 5, time of adduction of 13 min and temperature of 30-52 ºC

Optimization study on sewage sludge conditioning using Moringa oleifera seeds

Disposal of sewage sludge is a main problem faced by local municipalities in Malaysia. Sludge conditioned with chemical polymer often termed as undesirable use for land application. However, using natural polymer will help to reduce the impact of this problem. In this study, optimization using Moringa oleifera seeds as a natural polymer in sewage sludge conditioning is highlighted. An earlier sludge conditioning using jar test apparatus was conducted using Moringa oleifera seeds in three different forms; dry powder, distilled water extracted and salt extracted (1 N NaCl). Results from the study indicate that Moringa oleifera in distilled water extracted form shows the most optimum reduction in Capillary Suction Time (CST) value. Optimization of three important factors namely mixing speed, mixing duration and Moringa oleifera dosage for distilled water extracted form was done using Design of Experiments (DOE). Optimum values for the selected factors were obtained using Box-Behnken design, Response Surface Design Method (RSM). There was a total of seven set of optimized solutions produced. The best solution generated showed lowest CST and Specific Resistance to Filtration (SRF) was obtained at 4.5 s and 1.22 x 1011 m/kg respectively. These values were obtained under the optimum conditions of mixing speed at 100 rpm, mixing duration of 1 min and Moringa oleifera dosage of 4695 mg/L. The desirability index for the optimized solution was 1.000

Catalytic conversion of furfural extract from lubricating oil extraction unit over the shaped and promoted HY catalysts to valuable petroleum products

Catalytic conversion of a furfural extract from the extraction unit of lubricating oil to valuable products was investigated over the shaped HY extrudates using bentonite as binder (HY/bentonite) and zinc and nickel promoted HY/bentonite catalyst (Zn-Ni-HY/bentonite) in a bench scale fixed bed reactor. The catalysts were characterized by XRF, XRD, SEM and nitrogen adsorption-desorption. At 550 °C and LHSV of 9.2 h-1, 7.3 wt% gasoline was yielded over HY/bentonite catalyst, which was significantly increased (ca. 42%) over Zn-Ni-HY/bentonite catalyst. Besides, notably enhanced yield of light and heavy naphtha, kerosene, gas oil and lubricating oil can be distilled from the overall liquid products over Zn-Ni-HY/bentonite catalyst (90.5 wt%) than over HY/bentonite catalyst (77.6 wt%). The obtained petroleum products with the satisfied characteristics can be blended after hydrodesulfurization processing

Determination of storage volume required in a sub-surface stormwater detention/retention system

A new sub-surface detention/retention system, called the Storage–Infiltration Block (SIB) system, has been developed for the purposes of reduction of volume and flow rate of stormwater runoff and recharging groundwater. This paper presents a method in the determination of the maximum storage volume and maximum surface area required for the system. The method is based on the determination of the maximum difference between the volume of stormwater runoff entering the system and the volume released from the system by the infiltration process. The stormwater runoff inflow volume is determined using the Rational formula. The rainfall intensities were calculated based on the rainfall IDF relationships published by the Department of Irrigation and Drainage, Malaysia. An example is also included in this paper to demonstrate the calculation procedure. The example shows that the prediction of the maximum storage volume using this method is fast and accurate