542 research outputs found

    Power balance and control of transmission lines using static series compensator

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    Voltage profile Improvement Using Static Synchronous Compensator STATCOM

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    Static synchronous compensator (STATCOM) is a regulating device used in AC transmission systems as a source or a sink of reactive power. The most widely utilization of the STATCOM is in enhancing the voltage stability of the transmission line. A voltage regulator is a FACTs device used to adjust the voltage disturbance by injecting a controllable voltage into the system. This paper implement Nruro-Fuzzy controller to control the STATCOM to improve the voltage profile of the power network. The controller has been simulated for some kinds of disturbances and the results show improvements in voltage profile of the system. The performance of STATCOM with its controller was very close within 98% of the nominal value of the busbar voltage

    Oxidative stress contributes to cobalt oxide nanoparticles-induced cytotoxicity and DNA damage in human hepatocarcinoma cells.

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    BackgroundCobalt oxide nanoparticles (Co(3)O(4)NPs) are increasingly recognized for their utility in biological applications, magnetic resonance imaging, and drug delivery. However, little is known about the toxicity of Co(3)O(4)NPs in human cells.MethodsWe investigated the possible mechanisms of genotoxicity induced by Co(3)O(4)NPs in human hepatocarcinoma (HepG2) cells. Cell viability, reactive oxygen species (ROS), glutathione, thiobarbituric acid reactive substance, apoptosis, and DNA damage were assessed in HepG2 cells after Co(3)O(4)NPs and Co(2+) exposure.ResultsCo(3)O(4)NPs elicited a significant (P < 0.01) reduction in glutathione with a concomitant increase in lipid hydroperoxide, ROS generation, superoxide dismutase, and catalase activity after 24- and 48-hour exposure. Co(3)O(4)NPs had a mild cytotoxic effect in HepG2 cells; however, it induced ROS and oxidative stress, leading to DNA damage, a probable mechanism of genotoxicity. The comet assay showed a statistically significant (P < 0.01) dose- and time-related increase in DNA damage for Co(3)O(4)NPs, whereas Co(2+) induced less change than Co(3)O(4)NPs but significantly more than control.ConclusionOur results demonstrated that Co(3)O(4)NPs induced cytotoxicity and genotoxicity in HepG2 cells through ROS and oxidative stress

    Performance investigation of stand-alone induction generator based on STATCOM for wind power application

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    Self-Excited induction generators (SEIG) display a low voltage and frequency regulation due to variable applied load and input rotation speed. Current work presents a simulation and performance analysis of a three-phase wind-driven, SEIG connect to a three-phase load. In addition, an investigation of the dynamic operation of the induction generator from starting steady state until no-load operation. It is assumed that the input mechanical power is constant where the rotor of the SEIG rotates at a constant speed. The value of the excitation capacitance which is necessary to the operation of the induction generator also computed to ensure a smooth and self-excitation starting. The output voltage of the generator is adjusted by varying the reactive power injected by STATCOM. A 3-phase IGBT voltage source inverter with a fuel cell input supply is connected as STATCOM which is used to compensate for the reduction in the supply voltage and its frequency due to variation occurred in the applied loads. This work includes introducing a neuro-fuzzyy logic controller to enhance the performance of the SEIG by regulation the generated voltage and frequency The dynamic model of SEIG with STATCOM and loads are implemented using MATLAB/SIMULIN

    IL-33 stimulates expression of the GPR84 (EX33) fatty acid receptor gene and of cytokine and chemokine genes in human adipocytes

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    Expression of GPCR fatty acid sensor/receptor genes in adipocytes is modulated by inflammatory mediators, particularly IL-1β. In this study we examined whether the IL-1 gene superfamily member, IL-33, also regulates expression of the fatty acid receptor genes in adipocytes. Human fat cells, differentiated from preadipocytes, were incubated with IL-33 at three different dose levels for 3 or 24 h and mRNA measured by qPCR. Treatment with IL-33 induced a dose-dependent increase in GPR84 mRNA at 3 h, the level with the highest dose being 13.7-fold greater than in controls. Stimulation of GPR84 expression was transitory; the mRNA level was not elevated at 24 h. In contrast to GPR84, IL-33 had no effect on GPR120 expression. IL-33 markedly stimulated expression of the IL1B, CCL2, IL6, CXCL2 and CSF3 genes, but there was no effect on ADIPOQ expression. The largest effect was on CSF3, the mRNA level of which increased 183-fold over controls at 3 h with the highest dose of IL-33; there was a parallel increase in the secretion of G-CSF protein into the medium. It is concluded that in human adipocytes IL-33, which is synthesised in adipose tissue, has a strong stimulatory effect on the expression of cytokine and chemokine genes, particularly CSF3, and on the expression of GPR84, a pro-inflammatory fatty acid receptor

    Learning and Business Incubation Processes and Their Impact on Improving the Performance of Business Incubators

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    This study aimed to identify the learning and business incubation processes and their impact on developing the performance of business incubators in Gaza Strip, and the study relied on the descriptive analytical approach, and the study population consisted of all employees working in business incubators in Gaza Strip in addition to experts and consultants in incubators where their total number reached (62) individuals, and the researchers used the questionnaire as a main tool to collect data through the comprehensive survey method, where (55) questionnaires were retrieved with a recovery rate of (88.7%). The results of the study showed that there is a high approval of the variables of the study, where the dimension of incubation operations came with a relative weight (84.89%), followed by the learning dimension which got a relative weight (82.50%), while the performance level of the incubators got a relative weight (80.12%) and as the study results showed There is a positive relationship statistically between the two dimensions of learning and business incubation processes and performance development in business incubators, and the linear regression analysis model showed that the main effect in improving the performance of business incubators is "after business incubation operations" while it showed weak effect after learning. The study came out with several recommendations, the most important of which is that business incubators seek to reinforce the learning process and incubation processes for business, and the need to periodically evaluate their performance, and that a more effective mechanism be designed to follow up with companies after the end of the incubation period and monitor the progress of these companies

    Effect Of Parasitic Infection On The Enzymatic Function Of The Internal Organs Of Scomber Scombrus (Mackerel) And Euthynnus Alltteratus (Small Tuna) (Misrata, Libya)

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    The assessment of fish health has acknowledged the significance of helminthology and haematology characteristics as crucial instruments. The utilization of blood parameter measurement has been a longstanding practice in the field of fish health monitoring. The current study aimed to examine the impact of an indigenous infestation of parasites on various blood parameters, including activities of liver, kidney function tests, lipase, amylase, Creatine phosphokinase (CPK), and Lactate Dehydrogenase (LDH). The present study was undertaken to investigate the parasitic infection in a sample of 100 fish. The sample consisted of 50 of Euthynnus alletteratus, and 50 Scomber Scombrus. These fish were gathered from the waters of Misrata city, located in Libya. Results revealed the presence of statistically significant differences across various indices in both Euthynnus alletteratus and Scomber scombrus. A significant positive association was seen between urea values and many organs in Scomber scombrus, with the exception of the external body. Similarly, in Euthynnus alletteratus, a significant positive correlation was found between urea values and various organs, except for the external body and nostrils. The results of the study indicate that there is a positive link between creatinine levels and several internal organs in Euthynnus alletteratus, with the exception of external body tissues. A favorable correlation was seen between sodium levels and various organs in Scomber scombrus, with the exception of internal organs and the stomach. There was a positive correlation seen between potassium, Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), Alkaline Phosphatase (ALP), lipase, amylase, CPK, and total protein levels in several organs of both Euthynnus alletteratus and Scomber scombrus. A significant correlation was observed between LDH levels and several organs in both Euthynnus alletteratus and Scomber scombrus, with the exception of the external body in Scomber scombrus. In Euthynnus alletteratus, LDH levels were favorably connected with the nose, internal organs, and anterior intestine

    Measurements of the normal size of spleen and spleen to left kidney ratio among sudanese children up to five years age using ultrasonography

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    Background: Knowledge of the normal range of spleen size in the population being examined is very important because there are many different pathological conditions that may alter in spleen size. Also, gender, height, weight and BMI of individual, affect the splenic length and could result in incorrect interpretation of splenic measurements, spleen to left kidney ratio is one of recent parameter mention in literature aid in diagnosis of splenomegaly in children.Methods: The study was a cross-sectional study conducted in Khartoum state at Al-Buluk and Gaafar Ibnauf Paediatric Tertiary Hospital during the period from March 2018 to August 2018. A total of 101 children (males and females) with aged ranged 1 month to 5 years included in study. A transabdominal scan was performed, and measurement of spleen and left kidney taken after an ethical verbal consent from their parents, then data analyzed by SPSS, Mean±SD. Deviation for study variables calculated then correlation between patients factors and ultrasound measurements done.Results: The study found that the mean measurements of the normal size of the spleen and spleen to left kidney ratio for children up to five years of age, Splenic length was 7.24±1.12 cm, width was 3.83±0.81 cm , thickness 2.91±0.55 cm and spleen to left kidney ratio was 1.04±0.0.70 ranged (0.86-1.23). The male have larger spleen than female with no statistically significant differences in spleen sizes between the sexes. There was a strong significant correlation between age, weight, height  spleen and left kidney length (p<0.01)respectively and a moderate association with BMI (p<0.05).Conclusions: Spleen and left kidneys was growing rapidly and similarly in infant up to one year of life 1 mm\1 mm for each month and then decreasing growth rate of kidney in relate to spleen for 1 mm growth of spleen kidney grow 0.8 mm in up to five years of age. There was strong significant positive correlation between spleen and left kidney measurement with age, height, weight of individual. The spleen to left kidney ratio for children up to five years ranged (0.86-1.23) with mean 1.04, so if the ratio less or more than this ranged it should be considered in clinical context for diagnosis of splenomegaly or shrunken spleen in children up to five years of age
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