A New Scheme For Reduction Of Peak-To-A Verage Power Ratio In Orthogonal Frequency Division Multiplexing

Orthogonal Frequency Division Multiplexing (OFDM) is an attractive modulation method for channels with a non-flat frequency response. as it saves the need for complex equalizers. However. its main disadvantage is the high peak-to-average power ratio (PAPR) of the output signal. which may take values within a range that is proportional to the number of carriers in the system. As a result, a linear behavior of the system over a large dynamic range is needed and therefore the efficiency of the output amplifier is reduced. Many methods have been proposed to reduce the PAPR of the OFDM signal. among them a clipping technique which has been focused and investigated.OFDM signal, among them a clipping technique which has been focused and investigated. This thesis proposes a new scheme to reduce the PAPR. We name it Off technique. Further the effects of clipping scheme as well as the new scheme on the OFDM system performance in terms of Bit Error Rate (BER) and PAPR reduction is investigated. The results obtained indicate that both parameters, i .e. the reduction in PAPR and BER of this scheme were worse than those of the Clipping Scheme. In conclusion, results indicate that Off Technique does not offer a better solution to PAPR reduction in the OFDM system

Torsional behavior of reinforced recycled aggregate flowing concrete hollow section beams

Fifteen reinforced concrete beams made with recycled aggregates and flowing concrete, which were tested under pure torsion to study the torsional behavior. The major parameters in this study were the percent of the recycled aggregates and the number of transverse reinforcements. The torsional response and crack behavior were investigated in this study. From the results, it can be noted that the increase of the recycled aggregate led to a decrease in the critical and ultimate torque of the beam, also, the increasing the number of transverse reinforcements led to the enhancement of the critical and ultimate torque. Numerical analysis by finite element method was conducted and gave a good indicator for agreement in the results of critical and ultimate load between the numerical and experimental study, as well as the angle of twisting of the beam. The second approach was Hsu᾽s softened truss model, the model proves it can predict the critical and ultimate torque for the beam and showed its ability to describe the behavior of the beams before and after cracks

A New Mechanical Analysis of a Crankshaft-connecting Rod Dynamics Using Lagrange’s Trigonometric Identities

The main objective of this study was to conduct a new and simple but accurate analysis of the dynamics of a crankshaft-connecting rod system based on Lagrange’s trigonometric identities. Actual and equivalent connecting rod mass approximations of single- and multi-cylinder reciprocating engines were studied. Several examples were studied to demonstrate the dynamics of the system. Lagrange’s trigonometric identities were used to simplify the model, while MATLAB was used to obtain the results. For both the proposed reduced model and the full model, the resultant forces and torques of an actual and an equivalent connecting rod mass were compared. The results showed that the proposed reduced model gives force and torque results that match the results of the full model very well. It was shown that the largest torque imbalance resultant on the crankshaft was exerted by the two-cylinder engine. In addition, it was shown that the largest external forces resultant acting in the x-direction was exerted by the one-cylinder engine. The results also revealed that the resultant of external forces acting in the y-direction was zero for multi-cylinder engines. The relative error, which mainly occurred at the points of maximum force and torque, ranged from about 1% to about 15%

A New Mechanical Analysis of a Crankshaft-connecting Rod Dynamics Using Lagrange’s Trigonometric Identities

The main objective of this study was to conduct a new and simple but accurate analysis of the dynamics of a crankshaft-connecting rod system based on Lagrange’s trigonometric identities. Actual and equivalent connecting rod mass approximations of single- and multi-cylinder reciprocating engines were studied. Several examples were studied to demonstrate the dynamics of the system. Lagrange’s trigonometric identities were used to simplify the model, while MATLAB was used to obtain the results. For both the proposed reduced model and the full model, the resultant forces and torques of an actual and an equivalent connecting rod mass were compared. The results showed that the proposed reduced model gives force and torque results that match the results of the full model very well. It was shown that the largest torque imbalance resultant on the crankshaft was exerted by the two-cylinder engine. In addition, it was shown that the largest external forces resultant acting in the x-direction was exerted by the one-cylinder engine. The results also revealed that the resultant of external forces acting in the y-direction was zero for multi-cylinder engines. The relative error, which mainly occurred at the points of maximum force and torque, ranged from about 1% to about 15%

Preoperative evaluation of patients with ovarian masses using the risk of malignancy index 4 model

Objective: To evaluate the performance of the RMI 4 in discriminating benign from malignant ovarian masses. Study Design: Cross-sectional study. Setting: Assiut Women Health Hospital- Egypt. Materials and methods: This was an observational cross-sectional study involving 91 patients at Women\u27s Health Hospital, Assiut University, Egypt during the period between January, 2016 and January, 2017. Women with ovarian masses planned for surgical management were recruited from the outpatient gynecology clinic of the hospital. Risk of malignancy index (RMI 4) was calculated for all study participants. Biopsies obtained from the ovarian masses after surgical intervention were sent to the pathology lab for histopathological examination. The histopathologic diagnosis of the ovarian masses is considered the gold standard for diagnosis. Results: The mean age of patients in the benign group was 34.83±16.28 years versus 43.43±15.91 in the malignant group. There were 12 postmenopausal patients (15.6%) in the benign group versus 4 postmenopausal patients (28.6%) in the malignant group (p=0.0001). An ultrasound score of 4 was recorded in 85.7% of patients in the malignant group versus only 6.5% in the benign group (p=0.0001). Additionally, tumor size ≥ 7 cm was observed in 85.7% of patients in the malignant group versus 55.8% in the benign group (p=0.0001). The mean value of CA-125 was significantly higher in malignant group than the benign group (142.09±41.50 versus 54.51±32.86 ml, respectively) with p=0.01. RMI 4 had a sensitivity of 75%, specificity of 97.3%, PPV of 85.7%, NPV of 94.8 % and an overall accuracy of 93.4%. Conclusions: RMI 4 is a simple and reliable tool in the primary evaluation of patients with ovarian masses. It can further be used to discriminate benign from malignant ovarian masses with high sensitivity and accuracy

Effect of tranexamic acid in prevention of postpartum hemorrhage in elective caesarean delivery: a randomized controlled study

Background: Postpartum hemorrhage is the ugly ghost that most obstetricians believe because many cases unpredicted and may be associated with rapid patient deterioration that may lead mortality or developing serious long-term morbidities. The objective of this study is to assess the efficacy of slowly intravenous administration of tranexamic acid in prevention and decline the severity of postpartum hemorrhage immediately prior to elective caesarean section.Methods: A double blinded, randomized, case control trial carried out at Obstetrics and Gynecology Department, Faculty of Medicine, South Valley University, Egypt from May 2017 to April 2018. This study was conducted on 500 full term pregnant women underwent elective caesarean section. The patients were divided randomly into: Group A (study group) included 250 patients received tranexamic acid 1gm slowly iv over 2 minutes at least 10 minutes before operation started and Group B (control group) included 250 patients that received placebo (normal saline NaCl 0.9%).Results: Incidence of PPH in group A and group B were (4.4% and 6.8) respectively, 1.2% in group A and 2.8% in group B had severe degree of PPH. Amount of blood loss immediately after placental delivery up to first 6 hours postoperative was statistically significant increase in placebo group than tranexamic acid group with p value <0.001.Conclusions: Tranexamic acid administration few minutes prior to elective cesarean section was effective in reducing the incidence and severity of PPH and decreased the use of additional uterotonic drugs and additional surgical interventions

The Impact of Accreditation Standards in Developing Library and Information Science Master’s Degree Program in Jordan: A Comparative Study with American Library Association (ALA) Standards

Standards and their application are a tool to reach the required level of academic performance to ensure providing the society and labor market with a distinct level of graduates. Library science, as an academic field, is in dire need for such standards to raise the level of the scientific field and of functionality and library services. This is the ultimate goal of the field. This study evaluated Jordanian standards for Master Degree in Library Science through a comparison with the ALA standards. The study concluded that Jordanian standards are general for all postgraduate studies in all scientific fields, so there are no specific standards for the master’s program in library science. The Jordanian standards are issued by a commission which is not linked with the profession and this makes the standards lack too many necessary requirements for the scientific knowledge of libraries as a field of study and as a profession. Keywords: Standards; Master’s Degree; ALA standards; postgraduate studies; Jordan

A novel method to determine new potent angiotensin inhibitor, azilsartan, in human plasma via micelle-enhanced spectrofluorimetry using cremophor RH 40

Purpose: To develop a micelle-enhanced spectrofluorimetric method for the assay of azilsartan (AZL) in bulk form and spiked human plasma without the need for derivatization procedure.Method: The proposed method was based on studying the fluorescence behavior of AZL in Cremophor RH 40 (Cr RH 40) micellar system. The fluorescence intensity was measured at 371 nm after excitation at 264 nm. The proposed procedure was validated according to International Council on Harmonization (ICH) guidelines.Results: In aqueous solution, the fluorescence intensity of AZL was greatly enhanced by more than 3- fold in the presence of Cr RH 40. The fluorescence –concentration plot was linear over the range of 10 – 500 ng.mL-1, with a limit of detection of 3.287 ngmL-1. The proposed method was successfully applied to the determination of AZL in pure powder form and spiked human plasma. The mean recovery of AZL in spiked human plasma using the proposed method was 90.54 ± 1.17 %.Conclusion: The suggested method is highly sensitive and simple, and can easily be applied for the quantification of AZL in pure powder form as well as in biological fluids such as plasmaKeywords: Azilsartan, Spectrofluorimetry, Spiked human plasma, Micellar syste

Assessing information and communication technology in surgical training, Sudan as example

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