209 research outputs found

    A Pragmatic Study of Requests by Males and Females in Online Religious Forums

    Get PDF
    The current study investigates the request strategies used by males and females in online religious forums. It aims to explore request types realized by linguistic formulas used by males and females when they make requests in computer-mediated communication. The study offers pragmatic and sociolinguistic explanations for these differences. It also discusses the functions of these requestive forms such as asking for more clarifications or to request the addressee to answer a question directly. This study found that there are seven strategies used by the participants to make their requests. Most of which are shared by males and females. The study applied Chi-square test to show whether or not the differences in the use of each type of requests between the two groups (males and females) are statistically significant

    ECOLINGUISTICALLY INFORMED CRITICAL DISCOURSE ANALYSIS OF POLITICAL SPEECH ON CLIMATE CHANGE POLICIES IN THE UNITED STATES OF AMERICA

    Get PDF
    This study uses a mixed-methods approach to explore how climate change is conceptualized in the politics of the United States from the perspective of Ecolinguistics and Critical Discourse Analysis. I analyzed all the statements and letters issued by the governors and mayors who opposed the American president, Donald Trump, when he announced that he would withdraw the U.S. from the Paris climate agreement that 195 countries around the world signed. The qualitative analysis employs Critical Metaphor Analysis to investigate politicians metaphorical choices made to influence public opinion and influence policies about climate change in the U.S. These types of metaphors reinforce the rhetoric that creates climate change as an ongoing process where politicians construct and hold sociopolitical views through discursive use of metaphor. This is followed by a corpus analysis to investigate the changes in the discourse about climate change in the media before and after Donald Trumps announcement of the U.S. withdrawal from the Paris agreement in 2017. The results indicate that climate change is mainly framed as a long-term and threatening problem that policy makers should seriously deal with. This study can guide us to identify which politicians/groups make climate change a top priority. That is, politicians/groups that predominately use metaphors from certain source domains such as Journey, War and Construction on climate change are more concerned about climate change than politicians/groups that use metaphors from domains such as Unfairness and Business. This is because metaphors drawn from the source domains of War, Journey, Cleanliness and Construction emphasize dealing with climate change since they imply calling for action to address this problem. Metaphors drawn from Business, on the other hand, restrain action on climate change since they create excuses for delaying action or even not dealing with this environmental problem. However, it is not only what domain a metaphor is drawn from can determine if a politician/group (using that metaphor) supports or denounces responding to climate change (dealing with the problem as a top priority or not) but also this depends on what the purpose behind using that metaphor is

    CFD Modelling of pump as turbine with various number of blade for microhydro system

    Get PDF
    Pump as Turbine is an electromechanically component that is largely used in microhydro system. The main advantages of pump as turbine compared to commercially available turbines are lower cost, easier to maintain and readily available. These key features make them appealing to conditions in many developing countries. However, pump as turbine has poor hydraulic performance and low efficiency thus modifications were applied to improve the performance. The aim of this paper is to study the effect of impeller blade number to the pump as turbine performance. The investigation was carried out by using commercial Computational Fluid Dynamic (CFD) software, ANSYS CFX. A centrifugal pump with a specific speed of 70 with an impeller diameter of 214.0 mm was used to generate the CAD model. The original number of the blade was at 6 and varied to 5, 7 and 8 while other geometric dimensions were kept unchanged. The simulation results reveal that the highest efficiency was attained at 7 blade number with the efficiency recorded at 76.24%. The corresponding pressure was at 20.83 meters. It was found that with increase of blade number, the efficiency and corresponding pressure of the pump as turbine also increases. However, the additional blade number reduce the cross-area flow path, consequently increase the blockage effect thus decrease the net power generated by the rotating impeller

    Decoding of Decode and Forward (DF) Relay Protocol using Min-Sum Based Low Density Parity Check (LDPC) System

    Get PDF
    Decoding high complexity is a major issue to design a decode and forward (DF) relay protocol. Thus, the establishment of low complexity decoding system would beneficial to assist decode and forward relay protocol. This paper reviews existing methods for the min-sum based LDPC decoding system as the low complexity decoding system. Reference lists of chosen articles were further reviewed for associated publications. This paper introduces comprehensive system model representing and describing the methods developed for LDPC based for DF relay protocol. It is consists of a number of components: (1) encoder and modulation at the source node, (2) demodulation, decoding, encoding and modulation at relay node, and (3) demodulation and decoding at the destination node. This paper also proposes a new taxonomy for min-sum based LDPC decoding techniques, highlights some of the most important components such as data used, result performances and profiles the Variable and Check Node (VCN) operation methods that have the potential to be used in DF relay protocol. Min-sum based LDPC decoding methods have the potential to provide an objective measure the best tradeoff between low complexities decoding process and the decoding error performance, and emerge as a cost-effective solution for practical application

    Distributed Double Differential Space-Time Coding with Amplify-and-Forward Relaying

    Get PDF
    This paper provides the double differentially modulated distributed space-time coding for amplify-andforward (AF) relaying cooperative communications system under time-varying fading channels. In many wireless systems, the communication terminals are mobile. In such case, frequency offsets arise subjected to Doppler’s effect and frequency mismatch amongst the terminals’ local oscillators. The double differential coding is proposed to overcome the problem of frequency offsets that present in the channel due to the rapidly fast moving nodes. The advantage of the double differential is that the scheme requires neither channel nor frequency offset knowledge for decoding process at the desired destination. However, the conventional two-codeword approach fails to perform and leads to error floor, a region where the error probability performance curve flattens for high signal-to-noise ratio (SNR) regime in fast fading environment. Hence, a low complexity multiple-codeword double differential sphere decoding (MCDDSD) is proposed. The simulation results show that the proposed MCDDSD significantly improve the system performance in time-varying environment

    A survey of vertical handover decision algorithms in fourth generation heterogeneous wireless networks

    Get PDF
    Vertical handover decision (VHD) algorithms are indispensable components of the forthcoming Fourth Generation (4G) heterogeneous wireless networks architecture - so as to provide the requisite Quality of Service (QoS) to an assortment of applications anywhere at anytime, while allowing seamless roaming in highly dynamic scenarios (i.e. multitude of access network technologies) using terminals enabled with multiple access interfaces. This paper intends to present a comprehensive overview/survey of the VHD algorithms designed to satisfy these requirements, along with the main algorithms, protocols and tools proposed in the literature. To offer a systematic comparison, our survey categorized the algorithms in four groups based on the main handover decision criteria used. The survey revealed the need for devising an efficient algorithm which is truly useful in a wide ranging conditions, network parameters and user preference

    Vitamin D supplementation as an adjuvant therapy for patients with T2DM : an 18-month prospective interventional study

    Get PDF
    Background Vitamin D deficiency has been associated with impaired human insulin action, suggesting a role in the pathogenesis of diabetes mellitus type 2 (T2DM). In this prospective interventional study we investigated the effects of vitamin D3 supplementation on the metabolic profiles of Saudi T2DM subjects pre- and post-vitamin D supplementation over an 18-month period. Methods T2DM Saudi subjects (men, N = 34: Age: 56.6 ± 8.7 yr, BMI, 29.1 ± 3.3 kg/m2; women, N = 58: Age: 51.2 ± 10.6 yr, BMI 34.3 ± 4.9 kg/m2;) were recruited and given 2000 IU vitamin D3 daily for 18 months. Anthropometrics and fasting blood were collected (0, 6, 12, 18 months) to monitor serum 25-hydroxyvitamin D using specific ELISA, and to determine metabolic profiles by standard methods. Results In all subjects there was a significant increase in mean 25-hydroxyvitamin D levels from baseline (32.2 ± 1.5 nmol/L) to 18 months (54.7 ± 1.5 nmol/L; p < 0.001), as well as serum calcium (baseline = 2.3 ± 0.23 mmol/L vs. 18 months = 2.6 ± 0.1 mmol/L; p = 0.003). A significant decrease in LDL- (baseline = 4.4 ± 0.8 mmol/L vs. 18 months = 3.6 ± 0.8 mmol/L, p < 0.001] and total cholesterol (baseline = 5.4 ± 0.2 mmol/L vs. 18 months = 4.9 ± 0.3 mmol/L, p < 0.001) were noted, as well as a significant improvement in HOMA-β function ( p = 0.002). Majority of the improvements elicited were more prominent in women than men. Conclusion In the Saudi T2DM population receiving oral Vitamin D3 supplementation (2000 IU/day), circulating 25-hydroxyvitamin D levels remained below normal 18 months after the onset of treatment. Yet, this “suboptimal” supplementation significantly improved lipid profile with a favorable change in HDL/LDL ratio, and HOMA-β function, which were more pronounced in T2DM females

    Low Cost Solar Powered Telecenters for Malaysian Rural Areas : Case Study in Pos Sinderut, Pahang, Malaysia

    Get PDF
    The main objective of this project is to design and analyze the cost benefits solar PV system for rural telecenter. The project focused on designing the main solar system and solar panel energy performance based on translucency. The task that was carried out in this project was the selection of the suitable system that will suit the operation well while keeping the design cost as low as possible. In this project, the design of the solar panel system was focused on the electric loads and its cost benefit. Homer software was used to evaluate the solar panel system. Meant for ways of communications for indigenous people, the Solar Photovoltaic system is one of the popular solution for off-grid rural community power supply. The optimized combination for a particular rural site can be predicted based on NASA’s data of Solar Global Horizontal Irradiance (GHI). In this project, Pos Sinderut was chosen as the site, and the data load was measured. In our preliminary findings, it was found that the model on site was not suitably designed and maintained. The data parameters that was used for the on-site installed model was also not possible to be calculated when the model was simulated using Homer Software. As a result, we proposed a new model design by optimizing the load of VSAT and charging station based on the amount of solar PV and batteries that was supplied. This paper shows the significance of preliminary designs based on the irradiance and the usage load of the specific site before any installation should be commenced. It also showed how the site should be maintained properly in order to ensure a chosen site is sustainable for the rural community, post-installation

    Flexibility-based anti-islanding protection of a microgrid integrated with power grid

    Get PDF
    The widespread adoption of Renewable Energy Resources (RER) and Plug-in Electric Vehicles (PEVs) in distribution systems has achieved a substantial energy share, allowing the microgrid to participate in the open market. In fact, the high penetrations of RER and PEVs have increased the importance of impact assessment involving system protection. A framework is presented in this paper for modeling the combined operations of RER based solar Photovoltaic (PV) systems and PEVs in a microgrid integrated with power grid. The paper also proposes a fault current limiter connected in parallel (anti-islanding protection) with the circuit breaker in the point of common coupling (PCC), thus providing current bypass circuit during abnormal conditions. The concept of the proposed scheme is validated under various operating conditions using a 24-hourly dynamic simulation. The results demonstrate the effectiveness of the proposed approach

    CFD Modelling of a Pump as Turbine (PAT) with Rounded Leading Edge Impellers for Micro Hydro Systems

    Get PDF
    A Pump as Turbine (PAT) is one of micro hydro system components that is used to substitute a commercially available turbine due to its wide availability and low acquisition cost. However, PAT have high hydraulic losses due to differences in pumpturbine operation and hydraulic design. The fluid flowing inside the PAT is subjected to hydraulic losses due to the longer flow passage and unmatched fluid flow within the wall boundaries. This paper presents the effect of rounding the impeller leading edges of the pump on turbine performance. A CFD model of a PAT was designed to simulate virtual performance for the analysis. The aim of this study is to observe the internal hydraulic performance resulting from the changes in the performance characteristics. Highest efficiency was recorded at 17.0 l/s, an increase of 0.18%. The simulation results reveal that there is an improvement in hydraulic performance at overflow operation. The velocity vector visualization shows that there is a reduction in wake and consequently less flow separation along impeller flow passages. However, adjusting the sensitive impeller inlet geometry will also alter the velocity inlet vector and consequently change the velocity triangles for the turbo machinery system
    corecore