Multi-input DC-AC Inverter for Hybrid Renewable Energy Power System

The objective of this paper is to design a multi-input dc-ac inverter integrated photovoltaic array, wind turbine and fuel cell in order to simplify the hybrid power system and reduce the cost.  The output power characteristics of the photovoltaic array, wind turbine and fuel cell are introduced. The operational principle and technical details of the proposed multi-input dc-ac inverter is then explained. The proposed inverter consists of a three input flyback dc-dc converter and a single phase full bridge dc-ac inverter. The control strategy for the proposed inverter to distribute the power reasonably to the sources and it achieved a priority of the new energy utilization is discussed. This multi-input dc-ac inverter is capable of being operated in five conditions and power delivered to the ac load can be either individually or simultaneously. First to third condition occurs when the power delivered from either renewable energy sources individually, fourth condition happens when power is demanded from two sources simultaneously, and finally when power are available from three sources simultaneously. The proposed inverter has been simulated by employing NI Multisim 12.0 circuit simulator

Land-use classification and mapping using landsat imagery for GIS database in Langkawi Island

This study examined the land use changes in Langkawi Island for over 12 years. Land use maps were derived by analysing temporally available satellite imageries of that area. Subsequent Landsat imageries of the years 2006, 2014 and 2018 were processed in Environment for Visualising Images (ENVI) software using Normalize Differences Built-Up Index (NDBI) and supervised classification. The land use classes obtained were categorised according to the Soil and Water Assessment Tool (SWAT) land use classification namely URLD, URMD, URHD, FRSE, UINS, UIDU, URTN, RICE, AGRR, and WATR. The analysis of the land use maps provides a comparison for the area of land use class around Langkawi Island based on the Rancangan Kawasan Khas 2020 (RKK). This study will give an overview of the stakeholder on the current land use of Langkawi Island for future land use planning. Moreover, the land use map generated in this study can be used as a functional land use input for the SWAT model and provide a temporal Geographic Information System (GIS) database on the land use of the Langkawi Island

Determination of groove and mechanical properties of underside shaped concrete paver

This paper presents an innovative paver with groove beneath the normal rectangular paver, named as the Underside Shaped Concrete Paver (USCP). A known fact, there is less friction between surface at beneath of paver and bedding sand. Therefore, USCP provide their own grip to bedding sand especially during compaction process. The process of groove determination was first performed before the USCP were tested for compression and flexural strength. The groove was determined based on the theory of bending stress. Combined with several factors, the basic groove shapes chosen were rectangular and triangular. Results indicated that some groove shapes are better in compression, but have weak flexural strength and vice versa. In fact, the relationship between mechanical properties and groove shape is indisputable. It is hoped that the outcomes can be considered in the future to design desirable paver

The potential of waste cooking oil as bio-asphalt for alternative binder – an overview

Enormous quantity of waste products from by-products of frying activity could cause negative impact if not properly managed and disposed. Therefore, recyclability of Waste Cooking Oil (WCO) in binder modification to produce bio-asphalt can be a sustainable ways to minimize waste dumping while at the same time to reduce the usage of natural resources. Bio-asphalt can be described as alternative asphalt binder which differs from conventional asphalt in terms of strength and durability. This review has highlighted the potential of bio-binder to replace with conventional binder by the addition of waste cooking oil in the mixture

Properties of dense-graded asphalt mixture compacted at different temperatures

Poor compaction work is one of the identified causes of road failure and has always been a concern to the asphalt industry. The use of compaction machinery, compaction temperature, weather factor and the type of mixture used could potentially affect the asphalt pavement performance. This study measures the properties of hot mix asphalt (dense-graded AC10) prepared at different compaction temperatures. Various compaction temperatures were selected for the laboratory slab samples preparation i.e. 152°C, 142°C, 132°C and 122°C. A 60/70 pen bitumen was used to prepare the slab with the size of 305mm x 305mm x 50mm. Thermocouple was used to monitor the temperature of the mix. The slab samples were then cored for cylindrical samples at the approximate size of 100mm diameter for mechanical tests. The core samples were tested for volumetric properties, degree of compaction (DOC), Marshall stability and resilient modulus. It was found that low compaction temperature increases the air void in the total mix (VTM) and decreases the air void filled with bitumen (VFB) due to the increase in bitumen viscosity. In other words, reduction in compaction temperature resists the compactibility of the loose mix and resulted in low final DOC and low modulus

Assessment of knowledge, attitude and practice among house officers in UKM Medical Centre on needle stick injuries

Needle stick injury is one of the most serious occupational hazards among house officers in which it may lead to possible severe consequences such as HIV, Hepatitis B, and C infection. The aim of the study was to explore and compare the knowledge, attitude and practice (KAP) among house officers of UKM Medical Centre (UKMMC) regarding needle stick injury. A cross-sectional study was conducted with the total of 151 self-administered questionnaires from house officers in UKMMC within the period of five months. The data was collected via universal sampling method. Components evaluated were prevalence, demographic data and scores on KAP concerning needle stick injury among house officers. Out of the 151 house officers recruited for the study, 34.9% of them had a history of needle stick injury during their practice, with 6.7% of the injury that occurred in their current posting department. There was a significant association (p<0.05) between history of needle stick injury and the practice of house officers (p=0.035). House officers with a history of needle stick injury had a lower mean score of practice (8.65 ± 2.00) compared to those without history (9.40 ± 1.09). This study also demonstrated that there were significant correlations between Knowledge-Practice (r=0.194, p=0.018) and Attitude-Practice (r=0.182, p=0.026) of UKMMC house officers. These findings demonstrated that a good level of knowledge and attitude results in better practice of house officers hence reducing the incidence of needle stick injury. Therefore, suitable health education programs with regards to needle stick injury and preventive measures should be intensively implemented on all house officers prior to and during their practice

Properties of Stone Mastic Asphalt Incorporating Nano Titanium as Binder's Modifier

Stone mastic asphalt is a gap-graded mix and is usually related to its high bitumen content and its skeleton-like constitution. Although famous for its durability, high resistance to fatigue and rutting, issues such as bleeding and premature aging do occur in the mix since it has a high bitumen content and voids due to its gap-graded structure. In order to encounter these problems from affecting the mix, some instances such as adding additives, rejuvenators and stabilizers into the mixture has been implemented

Drug-coated balloon treatment in coronary artery disease: Recommendations from an Asia-Pacific Consensus Group

Coronary artery disease (CAD) is currently the leading cause of death globally, and the prevalence of thisdisease is growing more rapidly in the Asia-Pacific region than in Western countries. Although the useof metal coronary stents has rapidly increased thanks to the advancement of safety and efficacy of newergeneration drug eluting stent (DES), patients are still negatively affected by some the inherent limitationsof this type of treatment, such as stent thrombosis or restenosis, including neoatherosclerosis, andthe obligatory use of dual antiplatelet therapy (DAPT) with unknown optimal duration.Drug-coated balloon (DCB) treatment is based on a leave-nothing-behind concept and therefore it is notlimited by stent thrombosis and long-term DAPT; it directly delivers an anti-proliferative drug whichis coated on a balloon after improving coronary blood flow. At present, DCB treatment is recommendedas the first-line treatment option in metal stent-related restenosis linked to DES and bare metal stent.For de novo coronary lesions, the application of DCB treatment is extended further, for conditions suchas small vessel disease, bifurcation lesions, and chronic total occlusion lesions, and others. Recently,several reports have suggested that fractional flow reserve guided DCB application was safe for largercoronary artery lesions and showed good long-term outcomes. Therefore, the aim of these recommendationsof the consensus group was to provide adequate guidelines for patients with CAD based on objectiveevidence, and to extend the application of DCB to a wider variety of coronary diseases and guide theirmost effective and correct use in actual clinical practice

Schizophrenia and apolipoprotein: a 10-year bibliometric analysis

Introduction: Schizophrenia is a chronic and complex mental disorder that significantly impacts one’s quality of life. The expansion of proteomic studies over the past decade offers a better understanding of the underlying pathophysiology of schizophrenia and the formulation of a protein targeted therapeutic approach. This study aimed to conduct a bibliometric analysis on the role of apolipoprotein as a biomarker in schizophrenia to provide a summary of its chronicle, present state and to identify potential future research directions. Materials and method: Publications on the association between schizophrenia and apolipoprotein were retrieved from the Scopus database using the search terms “schizophrenia” and “apolipoprotein”. Only original or review articles in English published between 2013 and 2023 were included. The bibliometric analysis was carried out using the R software packages Bibliometrix and Biblioshiny. Results: The filtered search identified 89 documents (80 original articles and 9 review articles) that generally showed an increasing trend with an annual growth rate of 10.31 percent. There were 580 authors that contributed to this field, with an average of eight to nine people co-authoring each paper. Altogether, 64 journals contributed to this field, with Neuropsychiatric Disease and Treatment, Frontiers in Psychiatry, and Translational Psychiatry being the three most productive. China leads in scientific production, followed by the Netherlands and the United States. In terms of country collaboration, the United Kingdom and Germany had the highest level of collaboration. The important keywords in the clusters were schizophrenia, biomarkers, proteomics, apolipoprotein E, antipsychotic drugs, bipolar disorder, and obesity. According to the thematic evolution analysis, apolipoprotein E has been frequently discussed and associated with schizophrenia and antipsychotic drugs. Conclusion: The association between schizophrenia and apolipoprotein has grown in significance over the past decade. Our findings highlight the potential role of apolipoprotein E in the establishment of schizophrenia and warrant further exploration

The learning styles and academic achievements among arts and science streams student

This study aims to verify the statement that learning styles influence the academic achievements of students' in the arts and science streams. The main objectives of the study are 1) to seek if students' academic achievement has any significant relationship with their learning styles, 2) to determine the types of learning styles that have significant relationship with students' academic achievement in both the arts and science streams and 3) to determine the demographic factors that have significant relationship to the learning styles among Form 4 and 5 students of both the Arts and Science streams in one of the schools in the northern part of West Malaysia. To measure learning styles, six dimensions from the GRLSS (Grasha-Riechmann Learning Styles Scale) that are free style, avoidance, cooperation, dependent, competition, and participation will be used as the factors. a total of 100 responses were collected through the questionnaire distributed and received one at random which represent 100% response.The data analysis was conducted using SPSS v.19. the data was analysed and interpreted using descriptive and inferential statistics. Findings from the data analysis show that respondents prefer the dependent learning style followed by cooperation in all the variables namely gender, class, ethnic, family income and students' academic achievement. However, there can be a bit of a difference in terms of students who come from the home income of RM 2000, where they prefer cooperation followed by dependency.The Pearson Correlation analysis showed no significant relationship between learning styles as a whole with academic achievements, except for avoidance.The main findings also showed no significant relationship between learning styles and academic achievements. The discussion to findings, implications and suggestions for future researchers will also be presented in this study