Studying the Effect of Non-Linear Loads Harmonics on Electric Generator Power Rating Selection

Non-linear loads connected to an electric power system produce Harmonic currents, harmonics are introduced into the system in the form of currents whose frequencies are the integral multiples of the fundamental power system frequency (50/60 Hz). The harmonic currents interact with the supply system impedance causing distortions in supply output voltage and current, which has a very bad effect on all other loads connected to the system and the power supply itself, such as overheating, increasing powers losses in the system, and malfunction of protection and control devices connected to the system. This paper presents a study to analyze the effect of voltage and current harmonics resulting from non-linear loads such as variable frequency drive, uninterruptable power supply, and battery chargers on operation and power rating of synchronous generator. The study introduces an optimized method for selecting the suitable generator power rating to withstand harmful harmonics effects for a safe operation of the generator, saving its lifetime, and to improve the power quality of the power system. The method depends on analyzing the effect of increasing the supply generator power rating on the THVD produced from non-linear loads harmonics connected to the system. By calculating the THVD for each case of a generator power rating, a mathematical relationship between generator power rating and TVHD can be found. So, the relationship between generator power rating and total harmonic distortion in the power system will be discussed clearly

Pre- and Post-Fire Strength Assessment of Ferrocement beams

The results of an experimental investigation on the behavior of ferrocement beams after exposed to fire are presented in this paper. Different types of steel meshes are used compared with conventional reinforcement. The experimental program comprised casting and testing of eighteen beams having the dimensions of 100mm×100mm×1000mm. Three beams were reinforced as a conventional reinforcement. Each control beam was reinforced with two steel bars of diameter 8 mm in tension, two steel bar of diameter 6mm in compression and stirrups of 6 mm diameter placed at 200 mm intervals. The ferrocement beams were reinforced with steel meshes without any stirrups. Two types of steel meshes were used to reinforce the ferrocement laminate. These types are: square welded wire fabric, and expanded wire mesh. Single layer, double layers and three layers of square welded wire mesh were employed. Single layer and double layers of expanded wire mesh were employed. The experimental program was classified into three groups. First group was tested without exposure to fire, the second group was tested after exposure to fire for six hours and the last group was tested after exposure to fire under loading. All specimens were tested under 4-points flexural loadings. The performance of the test beams in terms of strength, stiffness, cracking behavior and energy absorption was investigated. The results showed that high serviceability and ultimate loads, crack resistance control, and better deformation characteristics could be achieved by using the proposed ferrocement forms

In vitro Anti-Leishmania Activity and Safety of Newly Synthesized Thiazolo Pyrimidine Derivatives Augmented with Interleukine-12 (IL-12) in BALB/c Mice Experimentally- Infected with Cutaneous Leishmaniasis

Purpose: To synthesize a series of novel thiazolo pyrimidine derivatives and evaluate them in vitro and in vivo for their safety and anti-leishmanial activity using BALB/c mice.Methods: Substituted pyrazolopyrimidine and pyrazolopyrazole were synthesized by reacting amino group of 2-amino-4-cyano-pyrazol]naphthalino[1,2-d]thiazole with a variety of formamide or hydrazine hydrate. The synthesized compounds were characterized by nuclear magnetic resonance spectroscopy (1H-NMR) and mass spectroscopy (MS). The purity of the compounds was determined by elemental analysis. Safety and anti-leishmanial activity of the compounds were determined in vitro by i) viability assessment of leishmania-infected macrophages, relative abundance of IL-12p40 mRNA gene expression and levels of IL10 /IL-12 determination in supernatants of cultured macrophages treated with 2.5 and 10 μM of the compounds, using microscope cell counting, reverse transcriptase polymerase chain reaction (RT-PCR) and enzyme linked immunosorbent assay (ELISA), respectively. ii) cytotoxicity of the compounds evaluated by determination the safety index as IC50 of the compound in macrophages/IC50 of the compound in amastigotes. iii) bioassay at 16 weeks post-infection of mice treated with the reference drug, the tested compound alone and both the compound with IL-12. Disease progression and footpad thickness were evaluated regularly during treatment.Results: Compound 4 emerged as the most active anti-protozoal compound of the series against Leishmania viability (activity 60 %) compared with the reference drug (activity 65 %). When it was combined with IL-12, the activity reached 90 %.Conclusion: Compound 4 can serve as a lead molecule for further development to a clinically useful novel class of agents.Keywords: Thiazolopyrimidine, Synthesis, Leishmaniasis, Mice, Immunotherap

Comparison between physical properties of ring-spun yarn and compact yarns spun from different pneumatic compacting systems

A comparative study pertaining to physical and mechanical properties of ring-spun yarn vis-à-vis compact yarns spun using three different compacting systems has been reported. Rieter (K-44), Toyota (RX-240) and Suessen (Fiomax) spinning machines have been used and the condensing process of the fibres in the yarn cross-section as per these compact spinning systems is accomplished pneumatically. Thus, a yarn of linear density 5.9 tex (100 Ne) is spun on the spinning systems using Egyptian cotton of the type Giza 86. One way Anova together with least significant difference are employed to feature the means of the properties of spun yarns and a significant difference among them is observed. According to the performed statistical analysis, there is a significant difference between ring - spun yarn properties and each of the pnuematic compact spun yarns. These compact-spun yarns are also found to differ significantly in terms of their physical and mechanical properties; however, they are all found superior to the ring-spun yarn

Short-term assessment of left ventricular function after coronary artery bypass grafting

Background: The effect of coronary artery bypass grafting on postoperative left ventricular function is still the subject of ongoing studies. The degree of recovery and its duration have not been precisely determined, and the published data are discordant. The objective of this study was to assess the effect of surgical revascularization on left ventricular systolic function. Methods: We prospectively studied 50 consecutive patients who underwent elective isolated coronary artery bypass grafting in the period from January 2017 to November 2017. All patients had echocardiography preoperatively, pre-discharge, and at 3 and 6 months postoperatively. Left ventricular end-systolic volume, left ventricular end-diastolic volume, stroke volume, and ejection fraction were measured in all patients. Results: The mean age was 57.22±7.04 years. The mean number of grafts was 2.60±1.02. Improvement in Canadian Cardiovascular Society (CCS) score from (2.72 ± 1.03) preoperatively to [(0.12 ± 0.39), p<0.001] after six months was achieved. Additionally, improvement in the patient New York Heart Association (NYHA) score occurred from (1.70 ± 0.97) preoperatively to [(0.12 ± 0.33), p<0.001] after six months. A significant improvement in left ventricular function occurred  as demonstrated by improvement in mean left ventricular ejection fraction from (54.14±9.80) % to  [(62.40 ± 4.18) %, p<0.001] at six months. The mean total hospital stay was 5.62±1.51 days. The mean total intensive care unit length of stay was 47.16±25.73 hours. Two patients (4%) had re-exploration for bleeding, and postoperative myocardial infarction occurred in three patients (6%).  One patient (2%) had postoperative neurocognitive dysfunction, and 3 patients (6%) had postoperative atrial fibrillation. Two patients (4%) suffered from superficial wound infection. There was no hospital mortality.   Conclusion: Patients undergoing CABG experienced an improvement in left ventricular contractile function at six months postoperatively. Further studies are required to evaluate the changes after 6 months

Equity incentives, earnings management and corporate governance: Empirical evidence using UK panel data

Using a UK panel data set drawn from 1675 Chief Executive Officer (CEO) year observations and 1540 Chief Financial Officer (CFO) year observations, we examine the relationship between CEO and CFO equity incentives and earnings management. In addition, we examine the moderation effect of corporate governance mechanisms on the relationship between executives’ equity incentives and earnings management. We use multivariate regression models to test our hypotheses. We find that CEO equity incentives are related to higher absolute and income increasing earnings management. These results support the managerial power theory argument that CEOs exploit equity-linked compensation to obtain more personal benefits without causing public anger. Contrary to CEO equity incentives, we could not find any significant relationship between CFO equity incentives and any of the earnings management proxies. In addition, we find that corporate governance quality (measured by individual mechanisms and overall index) has no effect on the relationship between executives’ equity incentives and earnings management. This result indicates that whereas some corporate governance mechanisms can reduce earnings management in general, they do not affect wealth driven incentives to manipulate accruals. In total, results question the effectiveness of the corporate governance system in mitigating opportunistic behavior motivated by executives’ compensation structures

Noise Effects on a Proposed Algorithm for Signal Reconstruction and Bandwidth Optimization

The development of wireless technology in recent years has increased the demand for channel resources within a limited spectrum. The system\u27s performance can be improved through bandwidth optimization, as the spectrum is a scarce resource. To reconstruct the signal, given incomplete knowledge about the original signal, signal reconstruction algorithms are needed. In this paper, we propose a new scheme for reducing the effect of adding additive white Gaussian noise (AWGN) using a noise reject filter (NRF) on a previously discussed algorithm for baseband signal transmission and reconstruction that can reconstruct most of the signal’s energy without any need to send most of the signal’s concentrated power like the conventional methods, thus achieving bandwidth optimization. The proposed scheme for noise reduction was tested for a pulse signal and stream of pulses with different rates (2, 4, 6, and 8 Mbps) and showed good reconstruction performance in terms of the normalized mean squared error (NMSE) and achieved an average enhancement of around 48%. The proposed schemes for signal reconstruction and noise reduction can be applied to different applications, such as ultra-wideband (UWB) communications, radio frequency identification (RFID) systems, mobile communication networks, and radar systems

CHARACTERIZATION OF A NEW BIOTYPE Moringa OF SAUDI ARABIA USING RAPD AND ISSR MARKERS

Moringa peregrina and M. oleifera are the only Moringa (Kelor) species found in Saudi Arabia. Both species are drought resistant and have very high nutritional and medicinal properties. Detection of genetic diversity is of great value for the improvement of nutritional and medicinal value of these plants. The aim of the present study was to characterize a new biotype Moringa observed in Al Bahah Region, Saudi Arabia. We used 11 RAPD and 15 ISSR primers to characterize and compare the new biotype with M. peregrina and M. oleifera. Level of polymorphism generated by each marker was calculated. We also calculate Nei’s coefficient to measure the genetic distance between the studied species. Level of polymorphism generated by RAPD and ISSR was 59.7% and 75%, respectively. RAPD and ISSR primers revealed that the new biotype shared 53 amplicons (43.44%) with both M. peregrina and M. oleifera, 29 amplicons with M. peregrina (2377%), 22 amplicons (18.03%) with M. oleifera, and displayed 18 unshared amplicons (14.75%). Based on RAPD data, genetic distance between M. oleifera and M. peregrina was 0.59, whereas genetic distance between the new biotype and M. oleifera and M. peregrina was 0.41 and 0.54, respectively. For ISSR data, genetic distance between M. oleifera and M. peregrina was 0.98, whereas genetic distance between the new biotype and M. oleifera and M. peregrina was 0.59 and 0.56, respectively

Characterization of a New Biotype Moringa of Saudi Arabia Using Rapd and Issr Markers

Moringa peregrina and M. oleifera are the only Moringa species found in Saudi Arabia. Both species are drought resistant and have very high nutritional and medicinal properties. Detection of genetic diversity is of great value for the improvement of nutritional and medicinal value of these plants. The aim of the present study was to characterize a new biotype Moringa observed in Al Bahah Region, Saudi Arabia. We used 11 RAPD and 15 ISSR primers to characterize and compare the new biotype with M. peregrina and M. oleifera. Level of polymorphism generated by each marker was calculated. We also calculate Nei and Li\u27s coefficient to measure the genetic distance between the studied species. Level of polymorphism generated by RAPD and ISSR was 46% and 57%, respectively. RAPD and ISSR primers revealed that the new biotype shared 55 amplicons (45.08%) with both M. peregrina and M. oleifera, 28 amplicons with M. peregrina (22.95%), 21 amplicons (17.21%) with M. oleifera, and displayed 18 unshared amplicons (14.75%). Based on RAPD data, genetic distance between M. oleifera and M. peregrina was 0.32, whereas genetic distance between the new biotype and M. oleifera and M. peregrina was 0.21 and 0.29, respectively. For ISSR data, genetic distance between M. oleifera and M. peregrina was 0.5, whereas genetic distance between the new biotype and M. oleifera and M. peregrina was 0.36 and 0.34, respectively. Based on these results we suggested that the new biotype is a hybrid crossbred between M. peregrina and M. oleifera