343 research outputs found

    The thermoluminescence response of doped SiO2 optical fibres subjected to fast neutrons

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    This paper describes a preliminary study of the thermoluminescence (TL) response of doped SiO2 optical fibres subjected to 241AmBe neutron irradiation. The TL materials, which comprise Al- and Ge-doped silica fibres, were exposed in close contact with the 241AmBe source to obtain fast neutron interactions through use of measurements obtained with and without a Cd filter (the filter being made to entirely enclose the fibres). The neutron irradiations were performed for exposure times of 1-, 2-, 3-, 5- and 7-days in a neutron tank filled with water. In this study, use was also made of the Monte Carlo N-particle (MCNPTM) code version 5 (V5) to simulate the neutron irradiations experiment. It was found that the commercially available Ge-doped and Al-doped optical fibres show a linear dose response subjected to fast neutrons from 241AmBe source up to seven days of irradiations. The simulation performed using MCNP5 also exhibits a similar pattern, albeit differing in sensitivity. The TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre, the total absorption cross section for Ge in both the fast and thermal neutrons region being some ten times greater than that of Al

    Examining the fit of social media as a tool to share disaster-related knowledge: From the perspective of task-technology fit theory

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    ICT is emerging as a process of knowledge-sharing without any physical and geographical constraints.ICT has successfully been used to disseminate knowledge during a constrained situation (i.e. disaster).In other words, ICT can be used to connect the public during a time of crisis.In Malaysia, the National Security Council(NSC) is one of the agencies responsible for managing disasters.Having a reputation as being a "champion of agencies", the NSC is responsible for providing a social media by which to share disaster-related knowledge with the public.Nevertheless, to what extent this social media actually supports the knowledge-sharing process is unknown.Hence, the purpose of this study is to determine the extent to which a social media actually supports the knowledge-sharing process; a theory known as Task-Technology Fit (TTF) is adopted. The data will be collected by distributing questionnaires to the users who have experience in accessing the social media tools of the NSC to acquire disaster-related knowledge during the occurrence of a disaster (i.e. flood). Structural Equation Modelling (SEM) will be used to analyze the data.The development of a theoretical research model will assist the agencies involved in disaster management to predict user evaluation of the social media tool in order to gather knowledge/information related to disasters

    Examining the determination of flood victim's knowledge sharing behavior: From the perspectives of social cognitive theory

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    During the occurrence of disaster, knowledge sharing plays as important role.Through effective knowledge sharing, it can help victims save lives; received immediate relief and support; and minimize the disaster effect.But lack of works has been done to examine the determinants of knowledge sharing within disaster management context. Therefore, this study aims to provide a better understanding of knowledge sharing during the occurrence of disaster.In order to examine the determinant of individual's knowledge sharing behavior during the occurrence of disaster, the researcher will use social cognitive theory (SCT) to conceptualize a theoretical model for this study.This study holds self-efficacy, reciprocity, social support and social recognition as an influence individual in sharing knowledge during the occurrence of disaster.The methodology begins with constructing a questionnaire to investigate the theoretical model.The respondents are victims that have had experience in sharing knowledge during the flood.This study was used a Structural Equation Modeling(SEM)to test causal relationships between constructs.Hopefully, by proposed theoretical model through this research can provide additional insight on what influence knowledge sharing behavior within disaster management context

    Examining the determination of flood victim’s knowledge sharing behavior: From the perspectives of social cognitive theory

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    During the occurrence of disaster, knowledge sharing plays as important role. Through effective knowledge sharing, it can help victims save lives; received immediate relief and support; and minimize the disaster effect. But lack of works has been done to examine the determinants of knowledge sharing within disaster management context.Therefore, this study aims to provide a better understanding of knowledge sharing during the occurrence of disaster.In order to examine the determinant of individual’s knowledge sharing behavior during the occurrence of disaster, the researcher will use social cognitive theory (SCT) to conceptualize a theoretical model for this study.This study holds self-efficacy, reciprocity, social support and social recognition as an influence individual in sharing knowledge during the occurrence of disaster.The methodology begins with constructing a questionnaire to investigate the theoretical model. The respondents are victims that have had experience in sharing knowledge during the flood.This study was used a Structural Equation Modeling (SEM) to test causal relationships between constructs.Hopefully, by proposed theoretical model through this research can provide additional insight on what influence knowledge sharing behavior within disaster management context

    Reduced graphene oxide-multiwalled carbon nanotubes hybrid film with low Pt loading as counter electrode for improved photovoltaic performance of dye-sensitised solar cells

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    In this work, the role of reduced graphene oxide (rGO) with hyperbranched surfactant and its hybridisation with multiwalled carbon nanotubes (MWCNTs) and platinum (Pt) nanoparticles (NPs) as counter electrode (CE) were investigated to determine the photovoltaic performance of dye-sensitised solar cells (DSSCs). Sodium 1,4-is(neopentyloxy)-3-(neopentyloxycarbonyl)- 1,4-dioxobutane-2-sulphonate (TC14) surfactant was utilised as dispersing and stabilising agent in electrochemical exfoliation to synthesise graphene oxide (GO) as initial solution for rGO production prior to its further hybridisation and fabrication as thin film. A chemical reduction process utilising hydrazine hydrate was conducted to produce rGO due to the low temperature process and water-based GO solution. Subsequently, hybrid solution was prepared by mixing 1 wt% MWCNTs into the produced rGO solution. TC14-rGO and TC14-rGO_MWCNTs hybrid solution were transferred into fluorine-doped tin oxide substrate to fabricate thin film by spraying deposition method. Finally, the CE films were prepared by coating with thin Pt NPs. Photoanode film was prepared by a two-step process: hydrothermal growth method to synthesise titanium dioxide nanowires (TiO2 NWs) and subsequent squeegee method to apply TiO2 NPs. According to solar simulator measurement, the highest energy conversion efficiency (η) was achieved by using CE-based TC14-rGO_MWCNTs/Pt (1.553%), with the highest short current density of 4.424 mA/cm2. The highest η was due to the high conductivity of CE hybrid film and the morphology of fabricated TiO2 NWs/TiO2 NPs. Consequently, the dye adsorption was high, and the photovoltaic performance of DSSCs was increased. This result also showed that rGO and rGO_MWCNTs hybrid can be used as considerable potential candidate materials to replace Pt gradually

    Fabrication and characterization of crystalline cupric oxide (CUO) films by simple immersion technique

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    Cupric oxide (CuO) is one of the most promising p-type semiconducting materials used in p-n junction solar cells. Most of the researchers use electrochemical deposition (ECD) to deposit CuO film. However, it always requires a conductive substrate and the resulting film is porous. In this work, we demonstrated a simple method using an immersion technique to deposit nanostructured CuO for p-n solar cell application. Compared to ECD which end up with only pyramid-like structure, an immersion technique offers flexibility on the CuO nanostructures such as spheres, particles, diamond etc. This technique also offers higher deposition rate which allow deposition at thicker thickness. The adherence to the substrate can be manipulated depending on the pH of the solution. The resuling film was tested into a p-n solar cell using configuration of Au/ZnO/Cuo/ITO/glass. Although there is no efficiency obtained under the solar radiation, it shows a solar cell characteristic with open circuit voltage (Voc) of 1.5

    Role of Antiviral Drugs in Management of Mild and Moderate Coronavirus Disease-19: A Systematic Review

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    This study was conducted to determine the objective role of antiviral drugs such as arbidol, lopinavir/ritonavir, and others in improving clinical symptoms, decreasing duration of hospitalization, and decreasing duration of viral shedding in patients with mild and moderate COVID-19 infection. A systematic literature search was carried out on Google Scholar and PubMed databases, using the keywords “COVID-19”, “Antiviral”, “Treatment”, and “Symptomatic” in various combinations. Observational studies, cohort and case control studies, and clinical trials published in English with full-text available were included in the study. Data extraction was carried out from selected studies, and all statistical analysis for the study was carried out using Microsoft Excel. The key outcomes studied were time to negative PCR, duration of clinical stay, time to clinical improvement, and occurrence of adverse events. Seven studies were selected for final review after rigorous selection process. Data of total 4734 participants was analyzed, the majority of which were females (n=2810, 59.3%). The majority of participants had mild disease (n=4197, 88.65%). Average time for negative RT-PCR in the included treatment groups was 13.5 days, whereas the average duration of hospitalization was 14.9 days for the treatment groups. Adverse reactions such as ECG changes, gastrointestinal symptoms, secondary bacterial infections, and hepatic and renal dysfunction were scarcely reported in the included studies. There is no clear benefit in terms of duration of hospitalization and time to negative PCR with the use of various antiviral regimens in mild disease; however, these drugs did play a role in limiting disease progression in the participant population. Pending further evidence, the use of these drugs for the management of COVID-19 is not recommend in patients with mild disease

    Exact solution for linear and nonlinear systems of PDEs by homotopy-perturbation method

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    In this paper, the homotopy-perturbation method (HPM)proposed by J.-H. He is adopted for solving linear and nonlinear systems of partial differential equations (PDEs). In this method, a homotopy parameter p, which takes the values from 0 to 1, is introduced. When p = 0, the system of equations usually reduces to a sufficiently simplified form, which normally admits a rather simple solution. As p gradually increases to 1, the system goes through a sequence of ‘deformations’, the solution of each of which is ‘close’ to that at the previous stage of ‘deformation’. Eventually at p = 1,the system takes the original form of the equation and the final stage of ‘deformation’ gives the desired solution. Some examples are presented to demonstrate the efficiency and simplicity of the method

    Analysis of two adjacent articulation Quranic letters based on MFCC and DTW

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    —Reciting al-Quran in the correct way is an obligatory duty for Muslims, and therefore learning al-Quran is a continuous education until the correct recitation is achieved. It is important to learn Tajweed rules to master the recitation of Quranic verses. Moreover, mastering the pronunciation of Arabic sounds is the first and key step to achieve accurate recitation of al-Quran. The rules were guided by the Islamic Scholars in fields related to al-Quran from their knowledge and experiences. Very limited researches were found in the perspective of sciences and engineering. In this paper two Quranic letters (ذ and ز) that are articulated from adjacent points of articulation were analyzed using Mel- frequency coefficient analysis. MFCCs matrices were calculated then compared using the dynamic time warping DTW technique to calculate the similarity matrices and find the similarity distance. Results show that letters from the same point of articulation have less similarity distance compared to the letters from different point of articulation
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