Aceh International Journal of Science and Technology
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Pilot Metal Workload in Flight Operation: A case study of Indonesian Civilian Pilot
Get PDFThis type of activity or work with high stress level and requires more concentration and attention, in this case is the aircraft operation. Thereby mental workload is the most dominant than the physical workload. And this is what should have been a concern, because if mental workload endured by pilot is excessive, it will lower down the quality of work and lead to work safety; in this case the aircraft operation. Subjective Workload Assessment Technique (SWAT) method is used to measure mental workload value, this method consists of three dimensions with their levels, there are: time, mental effort, and psychological stress load. The aim of this study was to know the mental workload of the pilot of an aircraft in flight dimensions: phases of time, phase of flight, terrain condition, and weather, and identifies what factors the most dominant for build of mental workload. The results of studies showed that pilot mental workload will increase when a pilot faced with flight conditions do at early morning (00.00-05:59 am), during weekend and enters the peak season period, and the aircraft will be landing procedures, and also in case of change of wind conditions in flight, and will increasingly when pilot exposed to aircraft operating with route condition which has a land surface is mountainious. This study also showed that the time dimension factor (T) significantly affects the mental workload of pilots, indicating that they put more emphasis on this factor when they are considering workloads
The Analysis of SEIRS-SEI Epidemic Models on Malaria with Regard to Human Recovery Rate
Get PDFThis article discusses SEIRS-SEI epidemic models on malaria with regard to human recovery rate. SEIRS-SEI in this model is an abbreviation of the population class used in the model, ie Susceptible, Exposed, Infected, and Recovered populations in humans and Susceptible, Exposed, and Infected populations in mosquito. These epidemic models belong to mathematical models which clarify a phenomenon of epidemic transmission of malaria by observing the human recovery rate after being infected and susceptible. Human population falls into four classes, namely susceptible humans, exposed humans, infected humans, and recovered humans. Meanwhile, mosquito population serving as vectors of the disease is divided into three classes, including susceptible mosquitoes, exposed mosquitoes, and infected mosquitoes. Such models are termed SEIRS-SEI epidemic models. Analytical discussion covers model formation, existence and stability of equilibrium points, as well as numerical simulation to find out the influence of human recovery rate on population dynamics of both species. The results show that the fixed point without disease ( ) is stable in condition and unstable in condition . The simulation results show that the given treatment has an influence on the dynamics of the human population and mosquitoes. If the human recovery rate from the infected state becomes susceptible to increased, then the number of infected populations of both species will decrease. As a result, the disease will not spread and within a certain time will disappear from the population
Adsorption of Textile Dye by Activated Carbon Made from Rice Straw and Oil Palm Midrib
Get PDFSynthetic dye wastewater from textile industries is characterized by strong color, high temperature, variable pH and high chemical oxygen demand (COD). The strong color of wastewater affects aesthetic and water transparency of water bodies. The metabolites could be toxic to aquatic biota and posing a potential hazard to human health. Eventually, it will cause severe environmental problems. One of method that has advantages in term of simplicity to remove synthetic dyes is adsorption. Environmentally benign and low-cost materials to make adsorbent are biomass-based materials. Two different biomaterial wastes of rice straw and oil palm midrib were used in this study to develop activated carbon adsorbents. These adsorbents were applied for the removal of Naphtol AS-G dye in aqueous solution. The effects of solution pH, adsorbents masses and contact time on dye adsorption were evaluated based on batch experiments. Removal of dye can be achieved within 60 minutes at a wide pH range starting from 4 to 8. At lower pH, synthetic dye removal was decreasing probably due to protonation of adsorbents active sites. The adsorption isotherms based on Langmuir and Freundlich models were analyzed. The isotherms analysis indicated that the adsorption by rice straw and oil palm can be represented by Langmuir and Freundlich isotherm model, respectively. Adsorption isotherms of Naphtol AS-G onto activated carbon are favorable with high adsorption capacity for both biomaterials. The mechanisms of color removal by activated carbon involved chemical and physical adsorption, in accordance with both the Langmuir and Freundlich models. The calculated maximum dye adsorption capacities onto rice straw and oil palm midrib activated carbon were 55.86 and 69.44 mg/g, respectively. Adsorption using biomass-based activated carbon offers a good technique for textile wastewater treatment as it could remove up to 95% of the color intensity besides reducing other pollutants such as COD, nitrate and phosphate
Adsorption of 2,4,6-trichlorophenol on kaolinite: DFT calculations
Get PDFThe aim of this work is to explore the adsorption process of an organic pollutant the 2,4,6-trichlorophenol on the clay mineral (kaolinite) surface in order to identify the sites of adsorption as well as conformations corresponding to the lowest energies. Ab-initio calculations have been used to investigate the adsorption process using a representative cluster model. According to the results obtained on the various studied models, the orientation of TCP on the surfaces clay affect the parameters such as : HOMO-LUMO energy gap, the enthalpy change (H), the thermal Gibbs free energy (G) and entropy contribution (S). The results point out a preferential adsorption of TCP on the octahedral surface and the NBO analysis indicates that the electron donor-acceptor complex was the dominant adsorption mechanism
Investigation of Subgrade Particles Acceleration Due To Dynamic Loading
Get PDFDetail investigation on flexible pavement due to of vehicles traversed was presented in this paper. The behaviour of subgrade particles acceleration on flexible pavement are investigated and is explained in order to obtain the comprehensive understanding about pavement. Investigation were conducted in the highway which have a yearly higway construction problems. The data collected represented three axis main principal direction (x, y and z axis) movements. The main objectives of this work is to evaluating the effects of vehicle traverse on the pavement to several parameter, such as acceleration, thickness of pavement and natural frequency of subgrade. The results are useful as a new approach of pavement design as well as flexible or concrete pavement by considering some parameters analyzed
Pedestrian Space Characteristics Analysis on Kyai Tapa-KH. Hasyim Ashari Street Corridor, West Jakarta
Get PDFThe city of Jakarta shows special characteristics in social, economic and cultural structures, a characteristic of urban life that gives much influence to its physical form. Development of the city is faced with problem of environmental degradation caused by unbalanced provision of urban infrastructure and facilities against the heterogeneity of urban needs and activities. The services provided by municipal government are more often unable to keep up with increasing demands of society's needs. Urban spatial and specific facilities built to expect community activities in accordance with the facilities built.This paper aims to put forward the results of studies that have been done about public perception use of pedestrian and public space area at object study, the characteristics of user's activities area region object of research and empirical data about the problem of pedestrian path as part of a public space that is related to behavior of community activity. The research method is Descriptive Analysis as a research that suggests the phenomenon that occurs and see and seek interrelations. It is a combination of descriptive survey method with analytical survey method of a phenomenon. Case studies presented as an object of analysis at a later stage, to be able to better explain the facts found and influence between variables. Built environment as product and work in form of space, volume, structure, ornament; needed as a message representing the norms and values of society, perceptions and aspirations, including developing their motivations and expectations explicitly or implicitly. City life activities require pedestrian space adapted to the aspirations of its people, as an effort to humanize pedestrians into the pedestrian area planning as a spatial dimension in urban area physical development
Physico-chemical characteristics of Composites material Based on Sulfonated Cyclone Fibre Cellulose and Benzotriazole
Get PDFComposites material based on sulfonated cyclone fibre cellulose (SCFC) and benzotriazole (Btri) have been prepared. Cyclone fibre cellulose (CFC) was sulfonated with trimethylsilyl chlorosulfonate (TMSCS), with high degree of sulfonation (150%). The composites material, SCFC-Btri were prepared by doping of benzotriazole in various mole ratios (0.125, 0.25 and 0.5). FTIR spectrum has confirmed the ionic interaction between sulfonic acid from sulfonated cyclone fibre cellulose and benzotriazole units. Thermogravimetric analysis (TGA) showed that the composites material was thermally stable up to 150 C. The results showed that methanol permeability of the composite material was lower than pristine Nafion112. Activation energy obtained for the materials are 0. 106 eV, 0.144 eV and 0.137 eV for SCFC-Btri mole ratios 0.125, 0.25 and 0.5 respectively, composites material was expected to be used as raw material in the fuel cell
Canteen Wastewater and Gray Water Treatment Using Subsurface Constructed Wetland-Multilayer Filtration Vertical Flow Type with Melati Air (Echindorus paleafolius)
Get PDFDomestic wastewater needs to be treated because it can pollute the environment, either water bodies, ground water, or soil. One alternative to treat domestic wastewater is using subsurface constructed wetland methods. This method has advantages, among others, cheap, simple technology and can be applied to the area of ample land. In this research, subsurface contructed wetlands-multilayer filtration with vertical flow type using Melati Air (Echindorus paleafolius) in field scale to treat domestic wastewater from canteens and gray water toilet of Senior High School at Bekasi with treatment capacity for 2261 L/day. Subsurface constructed wetlands-multilayer filtration with vertical flow type is an advanced treatment in this research. For preliminary treatment the collecting and aeration tank is used. Performance of subsurface constructed wetland-multilayer filtration with vertical flow type was able to achieve effluent COD parameters of 40 mg / L (standard 100 mg/L) from an average influent of 350 mg/L with removal efficiency of 90%, while BOD was successfully degraded to 33.00 mg/L (quality standard 30 mg/L) of an average influent concentration of 350 mg/L. In addition, the parameters analyzed are total nitrogen, the total phosphate succeeded to meet the quality standard. Based on the results of laboratory analysis, the reactor is able to treat organic loading of 500-700 kg BOD5/Ha/Day compared to previous research which is range from 40-300 kg BOD/Ha/ Day. Similarly, the value of K in this study ranged from 0.35-0.57 m/day for BOD and 0.37-0.45 m/day for COD compared to precious research which is 0.055-0.16 m / day for BOD and 0.027-0.16 m / day for COD
Biochar and Tillage Systems Influenced on Soil Physical Properties
Get PDFBiochar is known as a huge carbon storage in the soil. In the soil, biochar absorbs CO2 from air and keep them for hundred years. In addition to preventing reduce emission and green house effects, Biochar also contributes to soil productivity such as physical dan chemical properties of the soil. How biochar amends soil physical properties combined with some tillage systems are imperative to find out. Study aimed to determine the influence of biochar and tillage systems on some soil physical properties. Treatment arranged in a factorial randomized block design with three replications. The treatment of biochar effect consisting of four levels; 0, 10, 15, and 20 t ha-1 Biochar. The tillage systems were three levels; no, minimum, and conventional tillage. The results showed that we found an interaction effect on the biochar application with tillage systems on dried bulk density, soil porosity, and soil permeability. No interaction was found on aggregate stability indexes and soil water holding capacity at water content at -0.3 and -15 bar of water potential (pF 2.54 and 4.2, accordingly). Biochar amounting 10 t ha-1 combined with minimum tillage gave significant benefits on soil productivity in terms of dried bulk density, porosity and soil permeability
Effect of Different Mordants on Cotton Cloth Dyed with Aspergillus and Penicillium Dyes
Get PDFNatural dyes are an important alternative to potentially harmful synthetic dyes. This research was conducted using three kinds of Aspergillus dyes and six kinds of Penicillium dyes. In this study, Aspergillus and Penicillium were grown in mineral salts glucose medium. Premordanting technique was followed using different mordants, namely alum, CaCO3, CuSO4 5H2O, FeSO4 7H2O, K2Cr2O7 and MnSO4 H2O on cotton cloth. The colour of filtrate and range of colours developed on dyed materials were measured by RHS colour chart. The results indicated that the colour of dyed cloth was influenced by the addition of mordants, and different shades were obtained from the same dye filtrate using different mordants. FeSO4 7H2O was found as the most influential mordant. The present study shows a new source of fungal dyes, which can be used as an alternative for dyeing cloth