114 research outputs found

    Remediation of Polychlorinated Biphenyls (PCBs) through Bio and Phytoremediation in the Environment: A Review Study

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    One of the persistent organic pollutants (POPs) utilized globally between the 1930s and 1980s was polychlorinated biphenyls (PCBs). Even though their usage has been severely constrained, a lot of PCBs are still present in the environment, including soils and air. This local, national, international and governmental organizations regarding polychlorinated biphenyls and how can resolve and treat the problem sustainably. This can be achieved if seriously working on degrading persistent organic pollutants, especially polychlorinated biphenyls biologically via thorough research and sound implementation. The methods opted for remediation by the use of choosing suitable types of microorganisms and plants. These methods are practically active for the identification of the source, concentration level and effects on the ecosystem. It would help in developing appropriate strategy and data generation in formulating the inventories for the management of polychlorinated biphenyls in the future. It is also noted through numerous research that polychlorinated biphenyls are also found in human blood commonly analyzed by indicator congeners such as PCB 138,153, 180, and in air and soil markers of PCBs pollution include PCB congeners 28, 52,101,138,153 and 180 as well. The methods and mechanisms described for degrading the persistent pollutant in this research review the solutions for mitigating PCB pollution in an environment. The best option is to strictly ban it in Pakistan or weightage its usage with its multiple benefits and disadvantages. Promote biological treatment if the payback is healthy and environmentally sustainable

    Vehicular Ad Hoc Networks: Growth and Survey for Three Layers

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    A vehicular ad hoc network (VANET) is a mobile ad hoc network that allows wireless communication between vehicles, as well as between vehicles and roadside equipment. Communication between vehicles promotes safety and reliability, and can be a source of entertainment. We investigated the historical development, characteristics, and application fields of VANET and briefly introduced them in this study. Advantages and disadvantages were discussed based on our analysis and comparison of various classes of MAC and routing protocols applied to VANET. Ideas and breakthrough directions for inter-vehicle communication designs were proposed based on the characteristics of VANET. This article also illustrates physical, MAC, and network layer in details which represent the three layers of VANET. The main works of the active research institute on VANET were introduced to help researchers track related advanced research achievements on the subject

    Game Application as Teaching Tool to Assist Mastering Installation of Three-Phase Motor Control Topic: Expert Perception

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    The learning and teaching process using conventional methods might cause students to be unable to highlight their true potential. Besides, it can be more difficult for teachers to choose the types of games that suit the curriculum and students' needs. Hence, this study aims to develop a game application as a teaching assistant tool for a three-phase direct online starter topic in Electrical Technology Malaysian Vocational Certificate subject for Vocational College students using the Android platform. Learning materials and games are developed using multimedia and interactive elements to attract students to be active in using the learning medium based on game applications as 21st-century learning tools. The development purpose of the game application is to give early exposure to students to the installation of three-phase motor control before going through the laboratory session. The behaviorism learning theory and Game development Life Cycle (GDLC) model, were implemented in the game application development in this research. The researcher used Unity 3D software is online software such as Canva and Microsoft PowerPoint design tools interactively to make a game-based learning application for the three-phase motor control installation subject. Based on the analysis of the findings, the experts agreed that the functionality of this three-phase Motor Control game application can be used well and is suitable to be used as a teaching aid. In addition, these research results can be used by teachers to increase students' interest and further make the learning process more interesting to improve student understanding

    INFLUENCE OF SUBSTRATE TEMPERATURE ON THE STRUCTURAL AND OPTICAL PROPERTIES OF CdS THIN FILMS

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    CdS thin films were deposited on glass substrates at different temperatures by chemical spray pyrolysis. The prepared films were characterized by X-ray diffraction (XRD), Atomic Force Microscopy (AFM) and UV-Visible spectrophotometer. X-ray diffraction study shows a phase transition from cubic to hexagonal phase with the increase in substrate temperature from 200 °C to 400 °C and improves the crystalline of films. AFM analysis shows that the root mean square (RMS) surface roughness ranges from 15 nm for 200 °C films to 24.9 nm for 400 °C films. Optical characterization indicates that deposited film by chemical spray pyrolysis at different temperatures has a small decrease in band gap, which can be related to a phase change from cubic to hexagonal phase

    A compact size microstrip five poles hairpin band-pass filter using three-layers structure for Ku-band satellites application

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    This paper presents a reduced size microstrip five poles hairpin band-pass filter using three-layers structure for Ku-band satellites application. The three-layers structure shows a substantially reduced filter size and enlarged bandwidth. The filter has been designed based on five-pole resonators at 12.475 GHz and bandwidth of 550 MHz. This filter is designed on Rogers RO3003 substrate having relative permittivity (εr) of 3. The proposed band-pass filter has been designed with the help of Computer Simulation Technology (CST) software. Comparison analyses between the simulated insertion loss and reflection coefficient of RO3003 and FR4 substrates have been carried out in order to show the efficiency of the proposed filter design. Based on the obtained results, the proposed filter design achieves significant filter size reduction compared to other band-pass filters

    A compact size microstrip five poles hairpin band-pass filter using three-layers structure for Ku-band satellites application

    Get PDF
    This paper presents a reduced size microstrip five poles hairpin band-pass filter using three-layers structure for Ku-band satellites application. The three-layers structure shows a substantially reduced filter size and enlarged bandwidth. The filter has been designed based on five-pole resonators at 12.475 GHz and bandwidth of 550 MHz. This filter is designed on Rogers RO3003 substrate having relative permittivity (εr) of 3. The proposed band-pass filter has been designed with the help of Computer Simulation Technology (CST) software. Comparison analyses between the simulated insertion loss and reflection coefficient of RO3003 and FR4 substrates have been carried out in order to show the efficiency of the proposed filter design. Based on the obtained results, the proposed filter design achieves significant filter size reduction compared to other band-pass filters

    A Ten Year Descriptive Study of Adult Leukaemia at Al-Jomhori Teaching Hospital in Sana'a, Yemen

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    Background: There is scarcity of data of the epidemiology of leukaemia in Arab countries including Yemen. Understanding patterns of leukaemia underpins epidemiology and can provide insight into disease etiology. The aim of this research is to determine the epidemiologic pattern of adult leukaemia in Yemen.Methods: The research is a descriptive cross-sectional study. We analyzed the data of 702 adult patients with leukaemia, who were newly diagnosed over a ten-year period between October 1999 and October 2009 at the referral haematology centre in Sana’a at Al-Jomhori Teaching Hospital, according to type of leukaemia, age, sex, geographic distribution and time of diagnosis.Results: Acute Myeloid Leukaemia (AML) was found to be the most common (45.1%) followed by Chronic Myeloid Leukaemia (CML) (26.5%), Acute Lymphoid Leukaemia (ALL) (17.7%) and Chronic Lymphoid Leukaemia (CLL) (10.7%), respectively. There was an almost equal prevalence of AML and CML for males and females but males had significantly more cases of ALL and CLL (p =0.008). A significant variation in geographic pattern showed that the highest number of cases is seen the Central mountainous region and the least number of cases in the South-eastern region which is coastal and lowland (p<0.001). The seasonal variation showed that higher number of ALL cases was seen in the summer months (33%) compared with other seasons (21% in the spring, 24.2% in autumn and 21.8% in winter).Conclusions: The pattern of adult leukaemia in Yemen is different from that seen in western countries which could be attributed to different environmental exposure. The geographic pattern indicates a possible role of certain environmental factors which warrant further investigations. The pattern of seasonal variation needs further studies for evaluating the seasonality.

    The optimum condition for the synthesis of carbon nanofibers on activated carbon to remove lead from aqueous solution

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    Optimum process condition for the production of Carbon Nanofibers (CNFs) to remove lead ion (Pb) from aqueous solution is reported here. The CNFs were produced on the catalyst (Ni2+) impregnated palm oil-based cheap Powder Activated Carbon (PAC). Locally fabricated Chemical Vapour Deposition (CVD) system was used while acetylene (C2H2) was the carbon source. The porous nano-composite product is named “PAC-CNFs”, which was synthesized through a process using impregnated oil palm shell based PAC as a solid substrate. Design Expert 6.0.8 software was used to design the experimental plan and to determine the optimized process parameters for the growth of CNFs by using sorption capacity for Pb2+ by the PAC-CNFs adsorbent, as a response. The effect of different factors on the growth of CNFs including the temperature of CNFs growth (550 to 750 °C), time of growth (30 to 60 min), and the ratio of input C2H2/H2 gases (0.25 to 1.0) was evaluated. The predicted values for the sorption capacity of Pb2+ by the PAC-CNFs were in close agreement with the experimental data (R2 = 0.99). The optimal process condition: temperature for the growth of CNFs, time, and C2H2/H2 ratio was determined as 637 °C, 30 min, and 1.0, respectively. The CNFs grown under the optimized condition exhibited sorption capacity of 77 mg/g in removing Pb2+ from synthetic wastewater containing lead (Pb2+) ion
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