Optimization of Fuzzy Logic Controller for Supervisory Power System Stabilizers

This paper presents a powerful supervisory power system stabilizer (PSS) using an adaptive fuzzy logic controller driven by an adaptive fuzzy set (AFS). The system under study consists of two synchronous generators, each fitted with a PSS, which are connected via double transmission lines. Different types of PSS-controller techniques are considered. The proposed genetic adaptive fuzzy logic controller (GAFLC)-PSS, using 25 rules, is compared with a static fuzzy logic controller (SFLC) driven by a fixed fuzzy set (FFS) which has 49 rules. Both fuzzy logic controller (FLC) algorithms utilize the speed error and its rate of change as an input vector. The adaptive FLC algorithm uses a genetic algorithmto tune the parameters of the fuzzy set of each PSS. The FLC’s are simulated and tested when the system is subjected to different disturbances under a wide range of operating points. The proposed GAFLC using AFS reduced the computational time of the FLC, where the number of rules is reduced from 49 to 25 rules. In addition, the proposed adaptive FLC driven by a genetic algorithm also reduced the complexity of the fuzzy model, while achieving a good dynamic response of the system under study

Optimization of Fuzzy Logic Controller for Supervisory Power System Stabilizers

This paper presents a powerful supervisory power system stabilizer (PSS) using an adaptive fuzzy logic controller driven by an adaptive fuzzy set (AFS). The system under study consists of two synchronous generators, each fitted with a PSS, which are connected via double transmission lines. Different types of PSS-controller techniques are considered. The proposed genetic adaptive fuzzy logic controller (GAFLC)-PSS, using 25 rules, is compared with a static fuzzy logic controller (SFLC) driven by a fixed fuzzy set (FFS) which has 49 rules. Both fuzzy logic controller (FLC) algorithms utilize the speed error and its rate of change as an input vector. The adaptive FLC algorithm uses a genetic algorithmto tune the parameters of the fuzzy set of each PSS. The FLC’s are simulated and tested when the system is subjected to different disturbances under a wide range of operating points. The proposed GAFLC using AFS reduced the computational time of the FLC, where the number of rules is reduced from 49 to 25 rules. In addition, the proposed adaptive FLC driven by a genetic algorithm also reduced the complexity of the fuzzy model, while achieving a good dynamic response of the system under study

A numerical study to improve the position and angle of the producer gas injector inside the intake manifold to minimize emissions and efficiency enhancement of a bi engine

To develop a petrol engine so that it works under the bi-engine pattern (producer gas-petrol) without any additional engine modifications, a single-point injection method inside the intake manifold is a simple and inexpensive method. Still, it leads to poor mixing performance between the air and producer gas. This deficiency can cause unsatisfactory engine performance and high exhaust emissions. In order to improve the mixing inside the intake manifold, nine separate cases were modelled to evaluate the impact of the position and angle orientation inside the intake manifold on the uniformity and spread of the mixture under AFR=2.07. A petrol engine (1.6 L), the maximum engine speed (8000 rpm), and bi-engine mode (petrol-producer gas engine). The employ of the numerical simulation software (ANSYS workbench 19), the propagation, flow characteristics, and uniformity of the blend within the nine different cases were evaluated. According to the outcomes of the numerical simulation, it was found that creating vortices and turbulent flow for the producer gas and air inside the intake manifold is the perfect method to obtain a uniformity mixture of air and producer gas inside the intake manifold. In addition, extending the blending duration allows air and producer gas fuel to be mixed efficiently. Furthermore, the greatest uniformity and the maximum spread rate at the outlet of manifold are obtained in cases 1, 4, and 7, when the producer gas injector location is constant (P1, P2 or P3). In addition, the weakest spread of producer gas at the outlet of the manifold is observed in case 9 in comparison with the other cases. Moreover, it is observed that case (1) generated the maximum uniformity index (UI) leve

Antiulcerogenic effect of camel milk against ethanol induced gastric ulcers

Abstract The effect of oral administration of raw camel milk (5 ml/kg b.wt.) on ethanol-and aspirin-induced gastric ulcers was tested in rats. Oral administration of camel milk in rats with ethanol-induced gastric ulcer, significantly (P < 0.05) redudced the number of long ulcers, average length of ulcers, ulcer index and the volume of gastric juice. The total protein was significantly (P < 0.05) increased and the pH of gastric juice was not significantly changed. The curative ratio was 70.70% in camel milk treated group compared to 45.12% in ranitidine-treated rats. Oral administration of camel milk in rats with aspirin-induced gastric ulcers exhibited, significantly (P < 0.05), same actions with curative ratio of 65.03% compared to 34.03% in ranitidine-treated rats. In conclusion a significant protective effect of camel milk against ethanol-and aspirin-induced gastric ulcers was reported in rats

An Empirical Model for Optimizing the Sound Absorption of Single Layer MPP Based on Response Surface Methodology

Micro-perforated panel (MPP) is a thin panel absorber capable of absorbing sound energy at a targeted frequency range by adjusting the MPP parameters. An analytical model is available, but it is not a direct, convenient method for practitioners to determine the required MPP parameters. This paper presents an optimized empirical model to calculate the sound absorption coefficient of a single-layer MPP.  The response surface methodology is employed for a simple case to generate a second-order polynomial model through a sequence of designing processes to analyze the functional relationships and variation of the outcome performance (sound absorption coefficient) concerning the MPP parameters, namely the panel thickness, hole diameter, perforation ratio, and the depth of the back air layer.  The analysis is carried out for frequencies between 300 to 900 Hz. The predicted data (empirical) is compared with the actual data (analytical), leading to a coefficient of variation of 0.145%. The proposed empirical model can be used as a method to select the suitable MPP parameters according to the targeted frequency bandwidth of absorption with less computational time

The impact of multi-enzyme fortification on growth performance, intestinal morphology, nutrient digestibility, and meat quality of broiler chickens fed a standard or low-density diet

This research aimed to study the impact of supplementation of three multi-enzyme levels (0, 0.1, and 0.2% of feed) and two levels of dietary treatments [standard diet (SD) and low-density diet (LDD)] on growth performance, carcass traits, digestibility, and meat quality of broilers from 1 to 38 days of age. A total of 216 1-day-old Arbor Acres broiler chicks were randomly assigned to a factorial experiment (2 × 3) comprising six dietary treatments, each with six replicates and each replicate with six chickens. The results showed that the LDD significantly reduced body weight gain by 5.0%, compared with the SD. Multi-enzymes significantly improved body weight gain and the production index (PI) relative to the SD. The feed conversion ratio was significantly enhanced with increased multi-enzymes from 1 to 21 days. A significant relation between the multi-enzyme concentration and type of dietary treatment was observed in body weight gain and feed conversion ratio from 1 to 21 days of age. Nitrogen-free extract digestibility was significantly increased by using the SD diet compared with using the LDD. Multi-enzyme supplementation improved the digestibility of dry matter, crude protein, crude fiber, and nitrogen-free extract in the LDD. A significant relationship was found between the multi-enzyme concentration and type of dietary treatment on the pancreas, liver, and intestinal length percentages. The meat dry matter concentration was significantly higher in the LDD group than in the SD group. The low-density diet significantly reduced the total revenue compared with the SD, whereas broilers fed the SD recorded significantly higher total revenue and economic efficiency than those fed the LDD. The low-density diet significantly increased economic efficiency compared with the SD. Multi-enzymes significantly increased the total revenue, net revenue, and economic efficiency than the standard set. In conclusion, using multi-enzymes in broiler diets improved body weight gain. The LDD with multi-enzymes showed enhanced body weight gain compared with the SD without multi-enzymes

Impact of Lambda Value on Combustion Characteristics and Emissions of Syngas-Diesel Dual-Fuel Engine

A deep understanding of the ignition characteristics of syngas-diesel under different lambda values is essential for the application of dual-fuel combustion. In this study, the effect of increasing the lambda value was examined along with the emission characteristics and engine performance of syngas-diesel dual-fuel engines under a constant syngas-to-diesel substitution ratio of 52% at 2000 rpm engine speed. The work involved computational fluid dynamics analysis related to combustion for a four-stroke single-cylinder direct-injection engine. Combustion analysis was carried out using ANSYS Workbench (FLUENT) V16.1 software. According to the simulation results, the maximum pressure, temperature, and nitric oxide emission inside the combustion chamber increased with each increase in the value of lambda, while the emission of carbon dioxide and carbon monoxide decreased inside the engine

Occurrence of Hypothyroidism, Diabetes Mellitus, and Celiac Disease in Emirati Children with Down’s Syndrome

Objectives: Autoimmune diseases are known to occur in people with Down’s syndrome (DS), especially celiac disease, type 1 diabetes mellitus (DM), and hypothyroidism. Since there are common genetic risk factors involved in the occurrence of these autoimmune disorders, the risks would differ in different populations. We sought to determine the prevalence of type 1 DM, celiac disease, and hypothyroidism in Emirati patients with DS in Abu Dhabi, UAE. Methods: Ninety-two patients with DS were investigated for the presence of anti-thyroid antibodies, antithyroglobulin, and anti-thyroid peroxidase antibodies for hypothyroidism, anti-glutamic acid decarboxylase antibodies for type 1 DM, and anti-tissue transglutaminase immunoglobulin A antibodies for celiac disease. Results: Karyotyping was performed on 89 patients. Eighty-seven had non-disjunction of chromosome 21 (97.8%), one was a mosaic, and one had translocation. Of the patients studied, 19.6% had hypothyroidism, 4.3% had type 1 DM, and 1.1% had celiac disease. Out of the 92 patients studied, 66 (71.7%) did not have any autoimmune disease, 25 (27.2%) had one autoimmune disease, and one (1.1%) had two autoimmune diseases. Conclusions: Celiac disease was the least prevalent autoimmune disease in patients with DS patients, while type 1 DM and hypothyroidism were both significantly associated with DS

HRS white paper on clinical utilization of digital health technology.

This collaborative statement from the Digital Health Committee of the Heart Rhythm Society provides everyday clinical scenarios in which wearables may be utilized by patients for cardiovascular health and arrhythmia management. We describe herein the spectrum of wearables that are commercially available for patients, and their benefits, shortcomings and areas for technological improvement. Although wearables for rhythm diagnosis and management have not been examined in large randomized clinical trials, undoubtedly the usage of wearables has quickly escalated in clinical practice. This document is the first of a planned series in which we will update information on wearables as they are revised and released to consumers

Online teacher training in a context for forced immobility: the Case of Gaza, Palestine

This article discusses an action research study that involved the design and delivery of an online training course for teachers of Arabic to speakers of other languages in the Gaza Strip (Palestine). Grounded in Freirean pedagogy, the course aimed to respond to the employment needs of university graduates by creating opportunities for online language teaching. The action research study explored the dynamics at play within the online educational environment, to evidence elements that challenged and/or facilitated effective collaboration between trainers and trainees. This article retraces and discusses the processes through which the course moved from didacticism to engaged critical pedagogy