1,046 research outputs found
Comparative Analysis of Conventional and ICI-Self-Cancellation Digital Video Broadcasting Transceivers
Digital video broadcasting–terrestrial (DVB-T) is one of the important technologies in the communication area because of its capability of high data-rate multimedia transmission. Orthogonal frequency division multiplexing (OFDM) has been the backbone technique in the current DVB-T systems adopted by Europe and Japan. However, since the OFDM system is very sensitive to the frequency synchronization and phase errors, which will induce the intercarrier interference (ICI), the ongoing research has been dedicated to this ICI problem in the presence of the Doppler frequency drift and the fading channels. A means to deal with the ICI problem is called the ICI self-cancellation or polynomial cancellation coding scheme. In this thesis, we establish the complete simulation environment for the physical layer of the DVB-T system and then evaluate the effectiveness of the ICI self-cancellation coding scheme compared with the existing convolutional coding scheme for different fading channels and different Doppler frequencies. According to our simulation results, we conclude that the ICI self-cancellation scheme significantly outperforms the convolutional coding scheme which is adopted by the existing DVB-T standard in the AWGN and the frequency non-selective fading channels, but both schemes have the similar performance in the frequency selective fading channels
Prevalence of hepatitis B and C viruses among hemodialysis patients in Southern West Bank, Palestine
Background: In addition to severe renal impotence and decline of immune status, the high prevalence of hepatitis B and C virus’s infection represents one of the most critical clinical problems that are implicated in the progression of severe complication among hemodialysis patients. This study was performed to estimate the prevalence of hepatitis B and C viruses among hemodialysis patients and to recognize the pattern of chronic disease that will access to the renal failure.Methods: In this retrospective cohort study, data were collected from 252 hemodialysis patients for the presence of HBsAg, anti-HCV antibody, and the primary chronic disease that causes renal failure, in March 2013 from three governmental hospitals in southern West Bank in Palestine.Results: From 252 HD patients, 59% were male and 41% were female. 78% of them ranged between 15 and 65 years. 6.7% of all patients were HBsAg positive and 8.7% were anti-HCV antibodies are positive. Diabetes mellitus (33.7%), hypertension (23.7%), and chronic nephritis (6.0%), represent the most known primary chronic diseases that causes end stage renal disease.Conclusions: The role of the chronic diseases in accession to the renal failure, and the high prevalence of hepatitis B and C virus infection among hemodialysis patients compared to the normal healthy population indicate a causative relation between hemodialysis and hepatitis virus transmission.
Utilization of Lightweight Tetrapod Aggregate Produced from a High Calcium Fly Ash in Civil Engineering Applications
Due to the increasing volumes of fly ash production in some countries that depend on coal for running their thermal power plants, new utilization areas must be found. One of these areas is to utilize large volume applications such as the production of special shape aggregate (tetrapod) to be used in different geotechnical applications and highway construction. This is beneficial in solving the disposal problem of fly ash as well as making economical use of a mineral resource. To achieve these goals, fly ash was utilized in producing tetrapod shape lightweight aggregate by pressing into a specially designed mold. Pre to the production of tetrapods, regular lightweight fly ash aggregates were produced, cured and tested. Test results on the regular lightweight fly ash aggregates were implemented in the production of tetrapods. Optimization of lime content showed that five per cent by weight lime addition to fly ash had the best performance. Tests were conducted on the cured tetrapods in order to determine their mechanical and physical properties. Absorption and other properties were improved by surface treatment with water glass and heating
Editorial Comment for Sandhu et al.
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140372/1/end.2012.0411.pd
Effect of Superpave Short-Term Aging on Binder and Asphalt Mixture Rheology
This study aimed to evaluate the effect of Superpave short term aging period length and type of additive used in modifying the asphalt binder on the creep behavior of asphalt binder and asphalt mix. Hot-mix asphalt (HMA) specimens were prepared at optimum asphalt content using unmodified asphalt, or asphalt with 4% by weight of SBS or PE. The Universal Testing Machine was used to conduct dynamic creep tests. Tests results indicated that the effect of extending the aging period on creep deformation is highly dependent on type of additive used in preparing the asphalt mix. Extending the aging period more than three hours caused insignificant effect of creep behavior of control asphalt mixes. On the other hand, extending the aging period more than one hour caused insignificant effect of creep behavior of asphalt mixes prepared using SBS additive. While for mixes prepared using PE, the creep deformation continues to decrease as aging period increase
Breakup of turbulent liquid jets in still gases
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76376/1/AIAA-1999-3759-754.pd
Watershed Management, A Tool for Sustainable Safe Reuse Practice, Case Study: El-Salam Canal
In Egypt, drainage and irrigation network receives a complex mixture of industrial and domestic effluent. Therefore, water quality was subjected to rapid deterioration over the past decades. A need for using marginal quality water in agriculture for new expansion projects is becoming a great necessity. Good quality water is no longer available for new irrigation projects. One strategy to increase available water resources is to reuse agriculture drainage water for irrigation. Surface water of low quality along with limitation of current water resources was found to be the largest current environmental threat to the drainage reuse practice in Egypt. The detrimental effects of drainage water reuse can be minimized by adopting appropriate pollution sources management. Although domestic diffuse sources represent very small portion of the total discharge in drains, they contribute to a high percentage of organic load to the water system. Lack of investment and time required to execute proper wastewater treatment plants (WWTPs), become a constrain impeding the improvement in surface water quality. The proper water quality management system along with good planning for constructing, upgrading and upscaling of WWTPs within a certain watershed can positively improve the water quality at the mixing point with fresh water for reuse. In this study, a practical management tool based on watershed as one of the primer water system unit has been introduced. The tool works under GIS environment to help water managers and planners concerned in irrigation system to incorporate the reuse of drainage water to set best prioritization scenario of WWTPs implementation, upgrading or upscaling within the sub-watershed of El-Serw and Bahr-Hadous drains that feed El-Salam canal. The study is based on analyzing the transport and decay of pollutants expressed as BOD load through network analysis of drains network within El-Salam canal watershed as a case study. Keywords: Water quality management, Watershed, Drainage water reuse, GIS, Point source pollution (PSP), BOD. DOI: 10.7176/CER/11-4-06 Publication date:May 31st 2019
SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF SOFOSBUVIR AND DACLATASVIR IN PURE AND DOSAGE FORMS
Objective: Two simple, sensitive and accurate spectrophotometric methods have been developed for the determination of sofosbuvir (SOF) and daclatasvir (DAC) in pure forms and pharmaceutical formulations.
Methods: The proposed methods are based on the oxidation of SOF and DAC by a known excess of cerium(IV) ammonium nitrate in sulphuric acid medium followed by determination of unreacted cerium(IV) by adding a fixed amount of indigo carmine (IC) and alizarin red S (ARS) dyes followed by measuring the absorbance at 610 and 360 nm, respectively. The experimental conditions affecting the reaction were studied and optimized.
Results: The beer’s law was obeyed in the concentration ranges of 0.2-3.0, 0.2-4.0 for SOF and 0.5-4.5 and 0.5-5.0 μg/ml for DAC using IC and ARS methods, respectively with a correlation coefficient ≥ 0.9991. The calculated molar absorptivity values are 2.354 × 104, 1.933 × 104 for SOF and 1.786 × 104 and 2.015 × 104 L/mol. cm for DAC using IC and ARS methods, respectively u. The limits of detection and quantification are also reported. Intra-day and inter-day precision and accuracy of the methods have been evaluated.
Conclusion: The methods were successfully applied to the assay of SOF and DAC in tablets and the results were statistically compared with those of the reference method by applying Student’s t-test and F-test. No interference was observed from the common tablet excipients. The accuracy and reliability of the methods were further ascertained by performing recovery studies using the standard addition method
Evaluation of Road Pavement Maintenance by Contract in Jordan
In this research, road pavement maintenance by contract in Jordan was investigated. For this purpose, a subjective procedure (the Present Serviceability Rating (PSR)) was used to evaluate pavement serviceability. Three major highways (Jarash-Amman highway, Naour-Dead Sea highway and Zarqa-Syrian borders highway) that were maintained by contract were selected. The developed data base included information on pavement characteristics, traffic type and volume and routine maintenance cost. The effect of maintenance cost on pavement serviceability was estimated by developing a statistical relationship between maintenance cost and pavement serviceability rating before and after maintenance. The results showed that the pavement serviceability of Jarash-Amman highway and Naour-Dead Sea highway was adversely affected after applying maintenance by contract. The pavement serviceability of Zarqa-Syrian borders highway was slightly improved after applying maintenance by contract, but the improvement was not up to expectations. It is believed that the reasons for such results are a combination of the contractor’s poor experience and qualification and the timing of maintenance where the pavement was left without maintenance until it reached fair or poor condition
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