Institute Technology Padang

Padang, Indonesia

Institute Technology Padang

Padang, Indonesia
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Syarif J.,University of Sharjah | Handra N.,National University of Malaysia | Handra N.,Institute Technology Padang | Sajuri Z.,National University of Malaysia | Omar M.Z.,National University of Malaysia
Transactions of the Indian Institute of Metals | Year: 2017

The effect of Cu addition on the tensile properties of dual-phase steels with various volume fractions of martensite was investigated. An increase in the intercritical-annealing temperature resulted in an increase in the volume fraction of martensite and in the hardness of steel. The Cu addition increased the hardness of steel for all volume fractions of martensite. The tensile properties strongly depended on the Cu addition and on the volume fraction of martensite. The Cu addition significantly increased the ultimate tensile stress and elongation, but it showed a negligible influence on the 0.2% proof stress. The Cu addition improved strength–ductility stability, which referred to the multiplication of ultimate tensile stress and uniform elongation, for all volume fractions of martensite. Modified Crussard–Jaoul analysis on the true stress–true strain curve indicated that the work-hardening behavior of steel was improved by adding Cu. In pre-strained steels, the dislocation density was increased by adding Cu for all volume fractions of martensite. The improvement in work-hardening behavior was explained by the increase in dislocation density attributed to the addition of Cu. Therefore, it could be concluded that the Cu addition could increase dislocation density and work hardening, thereby increasing the ultimate tensile stress and improving the strength–ductility stability of steel. © 2017 The Indian Institute of Metals - IIM

Honesti L.,University of Technology Malaysia | Honesti L.,Institute Technology Padang | Majid M.Z.A.,University of Technology Malaysia | Djali N.,Bung Hatta University | Muchlian M.,Andalas University
Jurnal Teknologi | Year: 2015

Padang was destroyed by tsunamis generated by the earthquakes in the history of Padang. As an area located in a coastal region, its buildings in Padang face major vulnerability against a tsunami. The objectives of this study are to develop the potential impact model of building vulnerability toward tsunami hazard and to compare the building damage levels based on water inundation, internal, and external factors in Ulak Karang and Pasir Jambak sub-districts. The objective of this research is also to give recommendation to government in making planning strategies for reducing and managing the tsunami risk on building vulnerability. There are three stages of modeling; first stage in this study is simulating an eartquake model for two study areas to estimate the maximum inundation. The second stage of modeling is implementing the spatial analysis of building vulnerability based on the field surveys and GIS. The third stage to conlude is developing the Relative Vulnerability Index (RVI) scores of buildings by mapping the building vulnerability toward tsunami hazard and giving several alternatives to develop a risk management plan in a coastal community. The result shows that Ulak Karang sub-district is determined to be more vulnerable than Pasir Jambak sub-district because many buildings near the coastline of Ulak Karang sub-district are made of timber and are arranged close to each other. Moreover, many buildings in Ulak Karang sub-district, especially along the river, are made of traditional brick. Although near Pasir Jambak coastline many buildings are made of timber, but the buildings are not close to each other. There are several alternatives to increase resilience of buildings in a coastal zone, namely: 1) regulation for buildings that have RVI: 4 and 5; 2) building codes; 3) vertical evacuation structures; 4) land use zones; 5) sea walls along the coastlines; 6) natural barriers and 7) early warning system. © 2015 Penerbit UTM Press. All rights reserved.

Yahya M.,Institute Technology Padang | Fudholi A.,National University of Malaysia | Hafizh H.,University of Technology Malaysia | Sopian K.,National University of Malaysia
Solar Energy | Year: 2016

The performance of a solar dryer (SD) and a solar-assisted heat pump dryer (SAHPD) for drying of cassava chips have been investigated. The SD and SAHPD decreased the mass of cassava from 30.8 kg to 17.4 kg within 13 and 9 h at average temperatures of 40 °C and 45 °C, respectively. The moisture content of cassava decreased from 61% (wet basis) to 10.5%, with a mass flow rate of 0.124 kg/s. The average thermal efficiencies were 25.6% and 30.9% for SD and SAHPD respectively. The average drying rate (DR) and specific moisture extraction rate (SMER) were 1.33 kg/h and 0.38 kg/kW h, respectively, for SD as well as 1.93 kg/h and 0.47 kg/kW h, respectively, for SAHPD. The pick-up efficiencies varied from 3.9% to 65.8% and 15.9% to 70.4% for SD and SAHPD, with average values of 39.3% and 43.6%, respectively. The average solar fractions were 66.7% for SD and 44.6% for SAHPD. The coefficient of performance of the heat pump ranged from 3.23 to 3.47, with an average of 3.38. © 2016

Fudholi A.,National University of Malaysia | Sopian K.,National University of Malaysia | Gabbasa M.,National University of Malaysia | Bakhtyar B.,Northern University of Malaysia | And 3 more authors.
Renewable and Sustainable Energy Reviews | Year: 2015

The paper describes the techno-economic of solar drying system (SDS) with water based solar collector in Malaysia. In Malaysia, SDS has been great potential to be used in drying purpose, which is relevant to the local climate. The design, performance and economic analysis of four types SDSs with water based solar collectors in Malaysia were described, (1) SDS with hybrid PVT-mechanical heat pump, (2) SDS with chemical heat pump, (3) SDS with dehumidification system, and (4) Greenhouse SDS with heat exchanger. Economic indicators such as payback period (PP), net present value (NPV), and life cycle saving (LCS) were presented. In addition, the various performances analysis of SDSs with air based solar collectors was presented. The energy and exergy analysis of SDS with water based collector was presented. Moreover, the energy and exergy analysis of PVT water collector was presented. © 2015 Elsevier Ltd.

Premadi A.,National University of Malaysia | Premadi A.,Institute Technology Padang | Ng B.C.,National University of Malaysia | Ab-Rahman M.S.,National University of Malaysia | Jumari K.,National University of Malaysia
Annales des Telecommunications/Annals of Telecommunications | Year: 2010

This paper presented a simple monitoring, protection switching, and fast restoration approach for fiber to the home passive optical network (FTTH-PON) using Access Control System (ACS). ACS is developed for centralized monitoring and failure detection from central office (CO) in downstream direction (from CO towards customer sides). The proposed system architecture incorporating low cost and enable the network service providers and field engineers to remotely control the testing module from anywhere in the world and automatically identify any fiber fault and address the failure location in the fiber field. Another unique function of ACS is to provide the activation for optical switching in a restoration scheme which implemented at the drop region of FTTH-PON. A protection device named Customer Protection Device that comprises of programmable optical switches will be employed at the customer sides, just before the optical network unit, for rerouting the disrupted signals to the protection line when failure occurs in the working line to ensure continuous service delivery to customers. © 2010 Institut TELECOM and Springer-Verlag.

Premadi A.,Institute Technology Padang | Effendi A.,Institute Technology Padang | Bachtiar A.,Institute Technology Padang
Journal of Theoretical and Applied Information Technology | Year: 2016

This paper presents an experimental study for optical fiber network that uses 1550 nm and 1625 nm wavelength band light. We designed the system and network test-bed to measure optical power level or loss of optical power of each type of device or optical components in the Lab Network of ITP by using an Optical Time Domain Reflectometer (OTDR). The prototype of the device is fabricated and which achieves the target characteristics and reliability. In addition, it is confirmed that the prototype could detect fiber fault at 10.5222 km with system loss 18.21 dB within 13 minutes by setting the acquisition parameters in OTDR module. © 2005 - 2016 JATIT & LLS. All rights reserved.

Yahya M.,Institute Technology Padang
International Journal of Photoenergy | Year: 2016

The performance of a solar assisted heat pump dryer integrated with biomass furnace has been designed and evaluated for drying red chillies, and drying kinetics of red chillies were evaluated. The red chillies were dried from 22 kg with moisture content of 4.26 db to moisture content of 0.08 db which needed 11 hours, with the average drying chamber temperature, drying chamber relative humidity, and an air mass flow rate of 70.5°C, 10.1%, and 0.124 kg/s, respectively, while the open sun drying needed 62 hours. Compared to open sun drying, this dryer yielded 82% saving in drying time. The drying rate, the specific moisture extraction rate, and thermal efficiency of the dryer were estimated in average to be about 1.57 kg/h, 0.14 kg/kWh, and 9.03%, respectively. Three mathematical models, the Newton, Henderson-Pabis, and Page models, were fitted to the experimental data on red chillies dried by solar assisted heat pump dryer integrated with biomass furnace and open sun drying. The performance of these models was evaluated by comparing the coefficient of determination (R2), mean bias error (MBE), and root mean-square error (RMSE). The Page model gave the best results for representing drying kinetics of red chillies. © 2016 M. Yahya.

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