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International Journal of Science and Engineering (IJSE)
Published by Universitas Diponegoro
ISSN : -     EISSN : -     DOI : -
Core Subject : Engineering,
The scope of journal covers all area in the application on chemical, physical, mathematical, biological, agricultural, corrossion, and computer science to solve the engineering problems.
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Articles 14 Documents
Search results for , issue "Vol 8, No 1 (2015)" : 14 Documents clear
Drying Characteristics and Product Quality of Lemon Slices Dried with Hot Air Circulation Oven and Hybrid Heatpump Dryers Lee, Yong Hong; Chin, Siew Kian; Chung, Boon Kuan
International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (415.232 KB) | DOI: 10.12777/ijse.8.1.69-74

Abstract

In this research, drying characteristics and product quality of Coulomb-force-assisted heatpump and oven dried lemon slices were studied. Lemon slices with 3 mm thickness each, were dried using oven and Coulomb-force-assisted-heatpump dryer with and without auxiliary heater at different drying conditions. It was found that the drying rate of the lemon slices dried by all drying methods showed only falling rate states, which indicates the drying kinetics were controlled by internal moisture diffusion. Oven drying of lemon slices at 60°C showed the highest drying rate among all, followed by oven dried slices at 50°C, Coulomb-force-heater-assisted-heatpump (CF-HT-HP) dried slices at 31°C, Coulomb-force-assisted-heatpump (CF-HP) dried slices at 22°C, oven dried slices at 40°C and heatpump dried slices at 22°C. The average effective moisture diffusivity value for the slices dried with these drying methods was found in the range of 16.2 to 63.8´10-4 mm2min-1. In terms of quality assessment, CF-HP dried lemon slices retained the highest amount of Vitamin C as compared to the lemon slices dried by other drying methods. However, it retained relatively lower amount of total phenolic content (TPC) as compared to oven dried products. Among of all, CF-HP drying method produced dried lemon slices with the highest Vitamin C (6.74 mg AA / g dry weight) whereas oven dried lemon slices at 50°C preserved most of the TPC in the dried slices, which recorded as 13.76 mg GA / g dry weight.
Reliability based design optimization of concrete mix proportions using generalized ridge regression model Aggarwal, Rachna; Kumar, Maneek; Sharma, R.K.; Sharma, M.K.
International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (303.24 KB) | DOI: 10.12777/ijse.8.1.26-37

Abstract

This paper presents Reliability Based Design Optimization (RBDO) model to deal with uncertainties involved in concrete mix design process. The optimization problem is formulated in such a way that probabilistic concrete mix input parameters showing random characteristics are determined by minimizing the cost of concrete subjected to concrete compressive strength constraint for a given target reliability.  Linear and quadratic models based on Ordinary Least Square Regression (OLSR), Traditional Ridge Regression (TRR) and Generalized Ridge Regression (GRR) techniques have been explored to select the best model to explicitly represent compressive strength of concrete. The RBDO model is solved by Sequential Optimization and Reliability Assessment (SORA) method using fully quadratic GRR model. Optimization results for a wide range of target compressive strength and reliability levels of 0.90, 0.95 and 0.99 have been reported. Also, safety factor based Deterministic Design Optimization (DDO) designs for each case are obtained. It has been observed that deterministic optimal designs are cost effective but proposed RBDO model gives improved design performance.
Snap-Through Buckling Problem of Spherical Shell Structure Sumirin, Sumirin; Nuroji, Nuroji; Besari, Sahari
International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1336.92 KB) | DOI: 10.12777/ijse.8.1.54-59

Abstract

This paper presents results of a numerical study on the nonlinear behavior of shells undergoing snap-through instability. This research investigates the problem of snap-through buckling of spherical shells applying nonlinear finite element analysis utilizing ANSYS Program. The shell structure was modeled by axisymmetric thin shell of finite elements. Shells undergoing snap-through buckling meet with significant geometric change of their physical configuration, i.e. enduring large deflections during their deformation process. Therefore snap-through buckling of shells basically is a nonlinear problem. Nonlinear numerical operations need to be applied in their analysis. The problem was solved by a scheme of incremental iterative procedures applying Newton-Raphson method in combination with the known line search as well as the arc- length methods. The effects of thickness and depth variation of the shell is taken care of by considering their geometrical parameter l. The results of this study reveal that spherical shell structures subjected to pressure loading experience snap-through instability for values of l≥2.15. A form of ‘turn-back’ of the load-displacement curve took place at load levels prior to the achievement of the critical point. This phenomenon was observed for values of l=5.0 to l=7.0.
The impact of the local dairy cattle farm toward the river water quality in Gunungpati Subdistrict Central Java Widiastuti, E.; Kustono, Kustono; Adiarto, Adiarto; Nurliyani, Nurliyani
International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (687.871 KB) | DOI: 10.12777/ijse.8.1.15-21

Abstract

People’s awareness on the living environment nowadays is not yet comes up to the dairy-farmer community. In fact, the dairy-farm subsector contributes load pollution in the form of waste. The waste that is produced by a dairy-farm can be in the form of solid waste and liquid waste. There is still no cultivation effort toward the wastes in a traditional dairy-farmyet, thus most of the wastes are disposed to the closest river, so that in the surrounding dairy farm area is frequently found pollution toward the water quality. The aim of this study is to identify the effect of environment pollution that is caused by local dairy farm in Gunungpati Sub-district, especially toward the river water and residents’ well. The result of this study in Nangkasawit Village before and after the dairy farm was build was still under the quality standard for the third rate water quality. In Plalangan Village, the water quality was also under the quality standard, except for COD concentration. In the Sumurejo Village there was an upturn tendency on the observation value, but the water quality was under the quality standard, except for Fe concentration. Based on the Biodiversity Index before and after the dairy farm was established in Nangkasawit, Plalangan, and Sumurejo were 2.22, 1.49, 2.11, 1.90, 1.78, and 1.88, respectively. It means that Nangkasawit showed no pollution before the dairy farm was established, while there was a medium pollution after the dairy farm establishment.  In Plalangan, the water was clear, but it was light polluted after the dairy farm was established. In Sumurejo, before and after the dairy farm establishment the water was light category pollution.
TREATMENTS OF PLASMA CORONA RADIATION ON SEAWEED Gracilaria Verrucosa (HUDSON) PAPENFUSS: Efforts to increase growth and biomass Putra, Filemon Jalu N; Muhlisin, Zaenul; Putro, Sapto P.
International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (248.833 KB) | DOI: 10.12777/ijse.8.1.75-79

Abstract

Gracilaria verrucosa (Hudson) Papenfuss has great potential to be farmed in the water resources in Indonesia. As natural resource, the weed has a major contribution in the field of industry both for human food and health. Efforts have been done intensively to increase the production capacity to meet the market demand especially gelatin, both national and international market. One of them is the application of plasma corona irradiation treatments on the weed to improve developmental pathways. The concept of plasma irradiation performed at atmospheric conditions may impact on nitrogen intrusion pathway that is important element in the growth of the weed. The aims of this study are to assess the potential impact of plasma irradiation in improving the growth of G. verrucosa and thus increase their biomass production. The treatments were done using five different duration of plasma irradiation, which were 2, 4, 6, 8, and 10 minutes at a 0,5mA stable source of voltage and 8kV of electrical current. Observations of growth rate include thallus length and biomass of G. verrucosa , that was observed every week for 28 days. The result showed that the growth of weed exhibited better than those without radiation. The best growth was reached in the group of treatment of 8 minutes irradiation, exhibited 65,91g of biomass and 9.5515% growth rate and length of thallus reached 22,33 cm and daily growth rate of 2.9759%. The lowest growth of the weed occurred in the treatment of 10 minutes irradiation, which was 44,82 g biomass, 8.123% growth rate, 17,13 cm thallus length with a daily growth rate of 1.9942%
PROCESSING OF WATERMELON RIND DEHYDRATED CANDY Muhamad, Nur Farah Hani; Wan Zainon, Wan Nur Zahidah; Kormin, Saniah; Mohd. Akhir, Nurasmaliza; Ali, Muhammad Shah
International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (23.552 KB) | DOI: 10.12777/ijse.8.1.6-9

Abstract

Watermelon rind (Citrullus lanatus) dehydrated candy was prepared by using osmotic dehydration process that involves slow impregnation of syrup before drying at 50°C for 8, 14 and 20 hours. From the study, it can be seen that drying time significantly affected the moisture content of the watermelon rind dehydrated candy. The moisture content was significantly decreased with drying time. For colour evaluation, the L* value of watermelon rind dehydrated candy was slightly decreased with drying time while the a* value was slightly increased. Watermelon rind dehydrated candy that dried for 14 hours was the most preferred sample by the panelists as it received the highest score for texture, taste and overall acceptability attributes.  So, it can be concluded that 14 hours of drying time is the most appropriate time to dry the candied watermelon rind.  
Modelling of HTR (High Temperature Reactor) Pebble-Bed 10 MW to Determine Criticality as A Variations of Enrichment and Radius of the Fuel (Kernel) With the Monte Carlo Code MCNP4C Oktajianto, Hammam; Setiawati, Evi; Richardina, Very
International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (34.27 KB) | DOI: 10.12777/ijse.8.1.42-46

Abstract

Gas-cooled nuclear reactor is a Generation IV reactor which has been receiving significant attention due to many desired characteristics such as inherent safety, modularity, relatively low cost, short construction period, and easy financing. High temperature reactor (HTR) pebble-bed as one of type of gas-cooled reactor concept is getting attention. In HTR pebble-bed design, radius and enrichment of the fuel kernel are the key parameter that can be chosen freely to determine the desired value of criticality. This paper models HTR pebble-bed 10 MW and determines an effective of enrichment and radius of the fuel (Kernel) to get criticality value of reactor. The TRISO particle coated fuel particle which was modelled explicitly and distributed in the fuelled region of the fuel pebbles using a Simple-Cubic (SC) lattice. The pebble-bed balls and moderator balls distributed in the core zone using a Body-Centred Cubic lattice with assumption of a fresh fuel by the fuel enrichment was 7-17% at 1% range and the size of the fuel radius was 175-300 µm at 25 µm ranges. The geometrical model of the full reactor is obtained by using lattice and universe facilities provided by MCNP4C. The details of model are discussed with necessary simplifications. Criticality calculations were conducted by Monte Carlo transport code MCNP4C and continuous energy nuclear data library ENDF/B-VI. From calculation results can be concluded that an effective of enrichment and radius of fuel (Kernel) to achieve a critical condition was the enrichment of 15-17% at a radius of 200 µm, the enrichment of 13-17% at a radius of 225 µm, the enrichments of 12-15% at radius of 250 µm, the enrichments of 11-14% at a radius of 275 µm and the enrichment of 10-13% at a radius of 300 µm, so that the effective of enrichments and radii of fuel (Kernel) can be considered in the HTR 10 MW. Keywords—MCNP4C, HTR, enrichment, radius, criticality 
Codition of Coral Reef at Teluk Pandan Sub-District East Kutai District Syahrir R, Muhammad; Jayadi, Achmad; Adnan, Adnan; Yasser MF, Muhammad; Hanjoko, Tedy
International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (388.611 KB) | DOI: 10.12777/ijse.8.1.60-64

Abstract

Coral reef of TelukPandan Sub-district East Kutai District still low in both monitoring and management, thus also poorly in coral reef database. This research purpose was to obtain the data of coral reef condition and distribution description in this sub-district.  Research was held on October 2013 at six observation stations using lifeform line intercept transect survey method. The coral condition estimation was based on live coral cover (LC) and hard coral mortality index (HCM). Coral reef distribution and wide were estimated by satellite image Landsat 7 ETM+ processing and direct field tracking using GPS. There estimated ± 618.63 ha of coral reef area consist of fringing and patch reef formation type.  Live coral cover vary 2.1-67.8% or categorized “poor” to “good” reef condition and in average LC = 38.1% (“fair/moderate” condition).  Hard coral morality (HCM) index ranged 0.14 – 0.8 and in average 0.31.
DEVELOPMENT OF JAPANESE QUAIL (Coturnix coturnix japonica) EMBRYO Saraswati, Tyas Rini; Tana, Silvana
International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (923.648 KB) | DOI: 10.12777/ijse.8.1.38-41

Abstract

This experiment was conducted to determine the development of Japanese quail embryo (Coturnix coturnix japonica), through observation and measurement of embryo organ development from the age of one day until hatching. The study used 15 female quails and 5 male quails. 15 female quails were divided into 5 cages, each cage containing 3 quails females and 1 male quail. Eggs which are inserted into an egg incubator is produced when the quail began the age of 3 months. Descriptive observation has been made ​​towards the development of organs in the embryo. Based on the results of the study, the growth and development of quail embryo organs occur in stages until hatching occurred during the 16 days.
PRELIMINARY STUDY OF SEAWEED DRYING UNDER A SHADE AND IN A NATURAL DRAFT SOLAR DRYER Phang, Hooi-Kim; Chu, Chi-Ming; Kumaresan, Sivakumar; Rahman, Md. Mizanur; Yasir, Suhaimi Md.
International Journal of Science and Engineering Vol 8, No 1 (2015)
Publisher : Chemical Engineering Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (270.505 KB) | DOI: 10.12777/ijse.8.1.10-14

Abstract

A solar dryer was designed to study the seaweed drying process under natural convection and compared to a shade drying process. A dewatering pre-treatment process was initially applied to enhance drying process for both methods. The initial weight of seaweed before pre-treatment and after pre-treatment was recorded and the seaweed was then introduced into the solar drying system and shade drying system. The air temperature and relative humidity inside the solar dryer and surrounding were recorded during experiment. A representative sample on each tray was taken for final moisture content determination where the difference of seaweed weight less than 5% for subsequent measurement. The average weight loss of seaweed from pre-treatment was about 54%. The final moisture content of seaweed for solar drying was in the range of 24-61% (d.b.) and for shade drying was in the range of 40-48% (d.b.) with a standard deviation of final moisture content of 20.45% for solar drying and 3.78% for shade drying. The total time for solar drying inclusive of pre-treatment was 6 days and shade drying was 9 days. The drying kinetics of each method was modeled and the results of this study will be utilized to enhance the design and operations of seaweed solar dryers.

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