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Kumoro A.C.,Diponegoro University | Nasution D.A.,Indonesian Center for Agricultural Engineering Research and Development | Cifriadi A.,Indonesian Rubber Research Institute | Purbasari A.,Diponegoro University | Falaah A.F.,Indonesian Rubber Research Institute
International Journal of Applied Engineering Research | Year: 2014

This work aimed to determine the minimum fluidization velocity of biomass and river sand particles mixtures at various biomass mass fractions in the range of 0 to 1. Mixtures of river sand and rice husk or corn cob particles were chosen to represent mixtures of particles with different size, density and shape. Based on the experimental data obtained from the present work and those found in the literatures, a new correlation was developed to predict the minimum fluidization velocity for biomass and sand mixtures in terms of sphericity, Reynolds and Archimedes numbers. Further, it was found that the minimum fluidization velocity based on Archimedes number of biomass and sand particles mixture depends on the average sphericity of particles mixturesand the corresponding Reynolds number. The sphericity of the biomass and sand particles mixture affects Archimedes number of the mixture significantly in the laminar region, but does not affect the Archimedes number in the intermediate region. The predictions agree fairly well with the reported experimental and literatures data in the range of 1˂Re˂50, which cover both laminar and intermediate flows regions. This newly developed correlation is also applicable for the prediction of minimum fluidization velocity of inert or biomass particles only by setting the mass fraction to be 0 or 1 accordingly. © Research India Publications. Source

Paramawati R.,Indonesian Center for Agricultural Engineering Research and Development | Nasution D.A.,Indonesian Center for Agricultural Engineering Research and Development | Nurhasanah A.,Indonesian Center for Agricultural Engineering Research and Development | Sulistyosari N.,Indonesian Center for Agricultural Engineering Research and Development
Acta Horticulturae | Year: 2013

As a tropical country, Indonesia has plenty kinds of tropical fruits. Rambootan (Nephelium lappaceum) is one of the tropical fruits that is specific to South-East Asian countries, especially Indonesia. However, since rambootan is perishable it cannot easily be sold to other provinces or abroad. Rambootan still performs active respiration although it has been picked up from the tree, which will affect the physico-chemical characteristic and the shelf life. The aim of this research was to prolong the shelf life of rambootan by introducing carnauba coating and plastics wrapping combined with low temperature and CAS (controlled atmosphere storage). Treated and untreated fruit as control were stored at low temperature within cold storage (15°C). The characteristics including weight loss, sugar content (TSS) and total acid (TA) were observed periodically until all fruits were rejected by panelists which evaluated the sensory attributes. The results noted that rambootan stored with controlled atmosphere (CAS, 3% O2-5% CO2) at 15°C had prolonged shelf life up to 11 days based on sensory analysis of panelists on hairy skin color as critical sensory attributed to rambootan. Carnauba coating was the best method that could reduce the weight loss, followed by treatment without coating/wrapping. Moreover, all treatments showed a similar increase in total soluble solid (TSS) and total acid (TA) parameter, and then decrease after a certain number of days of storage. Source

Widodo T.W.,Indonesian Center for Agricultural Engineering Research and Development | Pitoyo J.,Indonesian Center for Agricultural Engineering Research and Development | Anggit D.,Indonesian Center for Agricultural Engineering Research and Development | Rahmarestia E.,Indonesian Center for Agricultural Engineering Research and Development
Acta Horticulturae | Year: 2013

Potato (Solanum tuberosum L.) is one of the important vegetable commodities in Indonesia. Productivity of potato is increasing year by year. However, potato farming still faces obstacles such as cultivar, seed, farming method, pest and disease control techniques, and also harvest and postharvest handlings. Experimental results indicated that 70% of total damage was caused by harvest, 30% during transportation and storage; more than 30% for all products may be damaged during harvesting. After harvest, potato requires to be classified for further handling purposes, such as for storage or marketing. However, the harvesting season is generally in the same period as land preparation and other activities resulting in lack of labors for grading. Moreover, potato is perishable and easy to decay if it is not well and fast handled. Thus, suitable machinery for potato grading is necessary. A prototype of the potato grader machine was designed to classify potatoes into four classes according to SNI 01-3175-1992 based on the weight that was converted into potato diameter, and then it was used for determining the roller distance of the grader machine. Performance test indicated that the machine capacity was 1800 kg/hour with less than 8% of grading error and less than 1% of potato damage (bruise). Manual grading needs 25 persons/day/ha, Rp 27500,- /person/day, with average of potato yield of 15 tons/ha, manual grading cost was 46,-/kg, whereas by potato grader with capacity of 1800 kg/hour, grading cost was Rp 26,-/kg, it reduced grading cost down to 43% lower than manual grading cost. Source

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