The increase of anthropogenic activites around the river bank possessed a great risk towards the water quality of the river. The wastewater which was discharged into river was not always treated properly. This condition could trigger a worsening pollution on the river. In Indonesia itself, there were 343 rivers which were found to have a worse water quality from time to time and remain unsolved until now. Meanwhile, there was Rambut River, located in the Tegal and Pemalang city border, which was at a risk of being polluted by the anthropogenic activities, e.g., agricultural and residential area. In this research, two different indicators were used a comparative analysis to determine how was the water quality in Rambut River, such as Water Pollution Index (WPI) and Water Quality Index (WQI). Both indicators showed similar results where the water quality in the upstream was better than the downstream. One sampling points in the most upstream part of the river was considered as clean or in good condition, while the others were lightly polluted. The results also showed that the sampling point which has the highest population density and dominated by agricultural and residential area were showing the worst water quality.

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With the modernisation of transport during the period of industrial urbanization, vehicles on the road are increasing, and it brings noise disturbances caused by the internal combustion engine of vehicles. This study involves the acoustical model development and analysis of the vehicle muffler. In this study, the resonator type of muffler is considered, and the transmission loss (TL) is used as the parameter to evaluate the acoustic performance of the muffler. The muffler CAD model is created using Solid works, and the acoustical analysis is conducted using COMSOL Multiphysics. The developed muffler model is tuned several times to obtain the optimum TL. The study yielded a wide range of TL across a range of frequencies. It is found that constrictions to the intake and exhaust pipes generated a higher TL by ~20dB than the original dimensions. Using an acoustic dampener further increases the TL of the muffler with a maximum increase of 18%. The inclusion of an acoustic dampener paired with the reduced diameter of the intake and exhaust pipes resulted in the analytical model generating the highest TL in the resonator muffler.

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The performance of these construction workers will determine the success of the Huntap project with the RISHA concept, and of course the good or bad performance of these workers is largely determined by several important factors that need to be studied in depth. Therefore, the purpose of this study is to find out what factors affect the performance of construction workers on fixed housing development projects with the RISHA system, and to determine the factors that have the most dominant influence on the performance of construction workers on fixed housing development projects with the RISHA system. This study used a purposive sampling technique with a total of 45 respondents. For data collection using questionnaires and documentation distribution techniques. Data analysis with factor analysis method. Based on the results of the study that there are five factors that influence the performance of construction workers in a permanent housing development project with the RISHA system in Central Sulawesi, the five factors are HR and management factors, competency factors and worker management methods, Talent, Interests and Material factors, change factors weather and equipment conditions, as well as skill factors and division of labor, in which the effect resulting from these five factors is 74.495% while the remaining 25.505% is influenced by factors that do not influence dominantly. Meanwhile, the results of the study also show that HR and management factors have the most dominant influence on the performance of construction workers in permanent housing development projects with the RISHA system in Central Sulawesi, with the highest variance value of 43.444%.

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Geopolymer concrete has been introduced as a green construction material as the Portland cement production involves a large amount of natural material and energy. The well-known sources materials to produce geopolymer concrete is a pozzolanic material and also a non-valuable or waste from the industrial production. This study, bagasse ash (BA) was the main constituent, which contained very high silica content. The calcined water supply sludge (CWS) was incorporated to the mixture as it contained substantial amount of alumina. The geopolymer concretes were cast by using 10 molars of NaOH and the NaOH/Na2SiO3 ratio of 1.0. The BA with partial replacement by CWS at 0-7.5% by weight, the alkaline solution to binder (AL/B) ratios in the range of 0.50-0.60, and the curing temperature between 40-100ēC were investigated. It found that the using CWS enhanced the workability of fresh mixtures and assisted the compressive strength of bagasse ash geopolymer concrete reached 40 MPa at 90 days. The low alkaline to binder ratio (AL/B) and high temperature of curing also encouraged the compressive strength of geopolymer concrete. However, the curing at 40ēC still provided the usable range of compressive strength. This is an opportunity to utilization worthless waste as construction materials and reduces the environmental impact.

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Variation in road conditions, increasing traffic loads and decreasing funds have presented a complex management challenge for the road maintenance and rehabilitation process. Consequently, there is a need to assess the pavement network condition, make decisions on maintenance strategies, set rehabilitation priorities and implement a maintenance management system. In this regard, Geographic Information System (GIS) is a powerful tool for managing and analyzing data referenced to a geographic location, especially in the field of road infrastructure where pavement section information stored in textual databases can be linked by location and attribute in geographic maps. This article proposes a macroscopic evaluation approach of the major pavement surface deteriorations using a GIS applied on a Moroccan national road section with 50 km length. Since its birth, and despite all the interventions carried out based on the visual inspection results analysis, this pavement underwent mainly the following deteriorations: potholes, pullouts and cracks. In this regard, using a matrix deterioration combinations developed by the Moroccan Center for Studies and Road Research, we proposed firstly a reduction of data relating to visual inspections conducted from 2008 to 2018, this step is essential to deduce the surface condition index (SUI) of this pavement, secondly to model them thematically by studying their temporal variation. This approach leads to facilitate the data reading, reduce the information, helps to take future decisions on the maintenance and propose a technical solutions to maintain the level of the pavement surface index.

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In this work, the reflection measurement on animal and vegetable oils due to different heating temperature was conducted using Agilent E8362B slim probe in conjunction with Agilent E8362B PNA Network Analyzer. The effect of thermal degradation on measured reflection efficient (G) is investigated. Many chemical processes are occurred when edible oils are heated during frying process. The thermal degradation products, i.e., volatile and non-volatile chemical compounds are generated. The generated volatile chemical compounds are dangerous to human health. Products of thermal degradation of animal and vegetable oils can be carcinogenic. On the other hand, it may cause diabetes, atherosclerosis, Alzheimer’s and Parkinson’s diseases, coronary heart disease, sudden cardiac death, and systemic vasculitis. Slim probe and open ended coaxial sensor are implemented to measure the reflection coefficient of the cooking oils. The fresh animal fats and vegetable oils are commercially available in local market. Five types of cooking oil (i.e. corn oil, olive oil, palm oil, sunflower oil and walnut oil) were measured at the temperature of 60ēC, 80ēC and 100 ēC for the frequency range of 3 GHz to 8GHz. When the oil is subjected to thermal degradation during heating, the chemical chain of oil will be altered and resulting in physical and internal properties change. It is the key element that led to the variation of G. G is function of physical-chemical properties of cooking oil that implying the oil quality. In reflection measurement, there are different noticeable results which indicates the used and fresh cooking oil and the effect of heating period.

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This study examines the effect of dimensionless numbers such as Reynolds, Nusselt, and Prandtl numbers and their variations on heat transfer characteristics in a heat sink of flat fins. This was done to understand the influence of Reynolds number and air temperature in the heat analysis of electronic cooling. A numerical study was conducted for the heat transfer analysis under steady and laminar flow conditions for Reynolds numbers ranged from 100 to 400 and inlet air temperature between 10 to 40 ēC. A finite volume method with a solution-independent grid was employed to solve the conjugate heat transfer problem. Reasonable agreement was found between calculated dimensionless number and that of published literature. It was observed that at the lowest limit of 10ēC, increasing the Reynolds number from100 to 200 causes a 0.52 % increase in Prandtl numbers and a drop in the increase to 0.35 % at 40ēC. Under a similar condition, the percentage increase is more noticeable for the Nusselt number, with an increase of 103.7 % dropping to about 60 % as the air temperature rises to 40 ēC. Also, increase similar to that of Nusselt number was observed for that of heat transfer coefficient. The overall results suggest that Reynolds number plays significant role on the heat transfer characteristics and this will have implication on the cooling strategies. The results obtained can be used in electronic heat sink cooling by programming the regulations of the Reynolds number as dictated by surrounding air temperature to effect suitable heat transfer occurrence. Also, the realization of the growth of the Nusselt and Prandtl numbers with heat transfer characteristic may lead to new insights for generating heat transfer correlations for future research.

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