scholarly journals Analisis Perubahan Waktu Pengeringan Terhadap Variasi Tinggi Cerobong

2019 ◽  
Vol 22 (1) ◽  
pp. 1-8
Author(s):  
Muhammad Syafrun
Keyword(s):  
Solar Energy ◽  
Water Content ◽  
Mechanical Engineering ◽  
Engineering Faculty ◽  
Hot Air ◽  
Time Required ◽  
Zinc Plate

This study aims to find out the efficiency of grain dryers using a chimney and a fan as suction air from the collector into the drying chamber.The research was conducted at the Central of Laboratory Department of Mechanical Engineering Faculty of Engineering, University of Muslim Indonesia, Makassar. A dryer was made from a zinc plate of 0.2 mm as collector by using a hot-air and solar energy as a drying medium. It was expected that this tool can  dry grain quickly with evenly distributed drying level or water content. There were five variations of  the Chimney : 20 cm, 50 cm, 80 cm, 110 cm and 140 cm with the grain thickness of 7 cm, 5 cm and 3 cm. The data were then analyzed to obtained the efficiency of the dryer. The results reveal that the time required to lower the water content of the harvest grain from 24.6% to 13.6% - 13.85% of milled moisture was 4 hours - 6.5 hours with an efficiency of 34,232 % for grain thicknes 7 cm, 31,480 % for grain thicknes 5 cm and 30,122 for grain thicknes 3 cm at 80 cm chimney height.

scholarly journals Development of a Compact Solar Vegetable Dehydrator

2021 ◽  
Author(s):  
S. V Jadhav ◽  
S. S Wangikar ◽  
A. M Kulkarni ◽  
M. K Patil ◽  
A. A Bansode ◽  
...  
Keyword(s):  
Solar Energy ◽  
Moisture Content ◽  
Shelf Life ◽  
Flow Velocity ◽  
Solar Collector ◽  
Agricultural Products ◽  
Hot Air ◽  
Different Temperatures ◽  
Passive Solar ◽  
Time Required

Agricultural products, such as, vegetables are generally perishable and are difficult to store. Drying is one method to reduce the increase their shelf life. Dehydrators use different type of energy as per availability and requirement. Solar dehydrators are more popular since they use renewable solar energy. In this paper such a domestic passive solar dehydrator is designed and analysed for its utility and effectiveness. The dehydrator is designed for converting the perishable agricultural products into powders so that it can be stored and used for longer time. It is designed in two parts. The first part work as a solar energy collector and the second part works as the dehydrator. The heat from solar radiations is imparted to the air in the solar collector. This hot air is used in dehydrator foe drying agricultural products. The experimentation has been performed for different temperatures and flow velocity of air varying for different vegetables depending on their moisture content and time required to remove the moisture. It is observed that drying at different temperature is required for different vegetables to convert them into powder. The taste and colour of the powder produced are found to be good. Therefore, it is suitable and affordable even for farmers with lesser quantity of products.

scholarly journals Application of microbial risk assessment on a residentially-operated Bio-toilet

2006 ◽  
Vol 4 (4) ◽  
pp. 479-486 ◽  
Author(s):  
Naoko Nakagawa ◽  
Hana Oe ◽  
Masahiro Otaki ◽  
Katsuyoshi Ishizaki
Keyword(s):  
Risk Assessment ◽  
Water Content ◽  
Risk Level ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Infectious Risk ◽  
The Matrix ◽  
Pathogenic Viruses ◽  
Scale Experiment ◽  
Time Required

The Sustainable Sanitation System is a new wastewater treatment system that incorporates a non-flushing toilet (Bio-toilet) that converts excreta into a reusable resource (as fertilizer or humus for organic agriculture) and reduces the pollution load to environments of the rivers, the lakes, and the sea. However, the risk of exposure to pathogens should be considered, because excrement is stored in the Bio-toilet. The aim of the present work is to analyze the health risk of dealing with the matrix (excreta and urine mixed with sawdust) of the Bio-toilet. Therefore, the fate of pathogenic viruses was investigated using coliphages as a virus index, and the modeling of the die-off rate in matrix was introduced. Then the microbial risk assessment was applied to a Bio-toilet that was actually used in a residential house; the infection risks of rotavirus and enterovirus as reference pathogens were calculated. According to the lab-scale experiment using coliphages for investing the die-off rate of viruses in the Bio-toilet, Qβ had a higher die-off, which was greatly influenced by the water content and temperature. On the other hand, T4 showed a lower rate and was independent of water content. Therefore, these two phages' data were used as critical examples, such as viruses having high or low possibilities of remaining in the Bio-toilet during the risk assessment analysis. As the result of the risk assessment, the storage time required for an acceptable infectious risk level has wide variations in both rotavirus and enterovirus cases depending on the phage that was used. These were 0–260 days' and 0–160 days' difference, respectively.

Understanding Why Engineering Students Take Too Long to Graduate

2013 ◽  
Author(s):  
Amir Karimi ◽  
Randall D. Manteufel
Keyword(s):  
Summer School ◽  
Mechanical Engineering ◽  
Engineering Students ◽  
Public Institution ◽  
Remedial Math ◽  
Science Courses ◽  
Part Time ◽  
Academic Records ◽  
Public Colleges And Universities ◽  
Time Required

There is growing pressure on public colleges and universities to decrease the time students take to earn an undergraduate degree. There are many factors that slow students’ progress towards graduation. For example, urban universities may have a significant number of non-traditional students who don’t take a full load of courses required to graduate in four years. Also, some freshman students interested in engineering may not be prepared for college and are required to take remedial math and science courses. Engineering is a highly-structured program, often with a long sequence of courses requiring one or more prerequisites. If some courses aren’t offered each semester, this can delay progress toward graduation for some students. This paper examines graduating students’ academic records and surveys senior-level mechanical engineering students to identify some of the causes for the increased graduation times. Students provided detailed information such as their full- or part-time status, how many semesters left to graduation, whether they attended summer school, the courses they had difficulty passing, and other issues related to the length of time required to complete their degrees. Feedback from students is essential as universities look to improve graduation rates. The results presented are based on the data for the mechanical engineering program at a public institution in Texas. Although each institution is unique, the findings presented in this paper are expected to apply to similar institutions throughout the nation.

Thermal performance of a packed bed double pass solar air heater with a latent heat storage system: an experimental investigation

2019 ◽  
Vol 17 (2) ◽  
pp. 203-213 ◽  
Author(s):  
Chaitanya Dosapati ◽  
Mohan Jagadeesh Kumar Mandapati
Keyword(s):  
Heat Transfer ◽  
Solar Energy ◽  
Solar Air Heater ◽  
Transfer Coefficients ◽  
Absorber Plate ◽  
Content Type ◽  
Heat Transfer Coefficients ◽  
Hot Air ◽  
Sunshine Hours ◽  
Poultry Farms

Purpose Solar energy applications are limited because of its intermittent and discontinuous availability with respect to time. Hence, solar energy thermal conversion systems need integration with thermal storage units (TSUs) to use solar energy in off sunshine hours. This paper aims to perform thermal analysis of a solar air heater (SAH) integrated with a phase change material (PCM)-based TSU to supply hot air during night period. Design/methodology/approach An experimental setup with TSU as main component was prepared with SAH at its upward side, food chamber at its downward side as subcomponents. In TSU, paraffin wax was used as thermal energy storage material. Mass flow rate of air considered as an input parameter in the experiment. Two different absorber plates, namely, plane and ribbed absorber plates were used for the experimentation. Each day for a fixed mass flow of air, observations were made during charging and discharging of PCM. Findings Nusselt number and convection heat transfer coefficients were analytically calculated by considering flow through TSU as external flow over bank of tubes in a rectangular duct. A temperature drop of around 7-8°C during charging of PCM and temperature rise of around 4-5°C during discharging of PCM was observed from the experimental results. The average practical efficiency of TSU with ribbed absorber plate SAH during charging and discharging of PCM was 22 and 6 per cent, respectively, higher than that of TSU with plane absorber plate SAH. Research limitations/implications There are no limitations for research on SAH integrated with TSU. Different PCM including paraffin wax, Glauber’s salt, salt hydrates and water are used for thermal storage. Only limitation is lower efficiency of SAH integrated with TSU because of lower heat transfer coefficients with air as working medium. If it can improve heat transfer coefficients of air then heat transfer rates with these units will be higher. Practical implications There are no practical limitations for research on SAH integrated with TSU. Sophisticated instrumentation is needed to measure flow rates, temperatures and pressure variations of air. Social implications In poultry farms during night, chicks cannot survive at cold climatic conditions. Hence, hot air should be supplied to poultry farms whenever the atmospheric temperature drops. It is proposed that, in combination with TSUs, heat produced by SAH is stored in day time in the form of either sensible or latent heat and is retrieved to provide hot air in the night times. This will reduce total operating costs in poultry farms. Originality/value Conventionally, people are producing hot air by combusting coal in poultry forms. This cost around Rs. 75,000 per month for a batch of 225 to 250 chicks in a poultry form. Hot air could be produced economically during off sunshine hours from SAH integrated with TSU compared to the conventional method of coal burning. Present experimental investigations conducted to fill the literature gap in this area of research and to design a SAH integrated with TSU to produce hot air for poultry forms.

Experiment and Analytical Studies Jujube Drying by the Solar Assisted Convection Drying

Solar Energy ◽  
2004 ◽  
Author(s):  
Minghu Cui
Keyword(s):  
Solar Energy ◽  
Drying Process ◽  
Drying Characteristics ◽  
Hot Air ◽  
Air Convection ◽  
Jujube Fruit ◽  
Save Energy ◽  
Drying Curves ◽  
Mass Transfers ◽  
And Behavior

An experimental setup, a mini-cabinet with reflector at its top, has been designed to study the drying process of jujube fruit by the convection and the solar radiation with hot air convection. The research experimentally investigated the drying characteristics and behavior of heat and mass transfer. Also, drying curves were analyzed. It demonstrated that solar energy could play an important role in promoting heat and mass transfers and saves energy consumed. The optimum conditions of appropriated temperature and humidity were obtained to save energy in solar energy convection drying process.

Plant minus air temperature corresponds to different responses to water stress in wheat, canola, and chickpea grown in the semiarid Canadian prairie

2019 ◽  
Vol 99 (6) ◽  
pp. 955-957
Author(s):  
Sangu Angadi ◽  
Herb Cutforth ◽  
Brian McConkey
Keyword(s):  
Water Stress ◽  
Solar Energy ◽  
Water Content ◽  
Water Deficit ◽  
Air Temperature ◽  
Canadian Prairie ◽  
The Difference

The difference between plant and air temperature (PT–AT) is a good indicator of water stress. PT–AT for chickpea was negatively correlated to water deficit and air temperature and positively correlated to wind; for wheat, PT–AT was positively correlated to water deficit, air temperature and solar energy; for canola, PT–AT was not correlated to the environment. Chickpea maintained positive turgor at the expense of water content and therefore more water was available for transpirational cooling. Wheat maintained water content at the expense of turgor and therefore there was little water available for transpirational cooling. For canola, PT–AT was affected by parameters other than environment.

The use of unsaturated salt solutions to generate conifer needle water-release curves

1991 ◽  
Vol 21 (1) ◽  
pp. 53-57 ◽  
Author(s):  
N. J. Livingston ◽  
E. de Jong
Keyword(s):  
Water Content ◽  
Black Spruce ◽  
Salt Solutions ◽  
Water Release ◽  
Needle Age ◽  
Relative Water ◽  
Rapid Generation ◽  
Time Required ◽  
Precision Balance ◽  
Conifer Needle

Reversible changes in cell wall water content, elasticity, and osmotic adjustment are all important drought tolerance mechanisms. Pressure chambers have been used extensively to generate water-release curves from which these basic water relations parameters are derived. Major limitations of this technique include the considerable time required to generate water-release curves and the difficulty in avoiding damage to tissue during the process. A simple and practical technique is descried that overcomes these limitations and allows the routine and rapid generation of water-release curves. Needles were removed from hydrated black spruce (Piceamariana (Mill.) B.S.P.) shoots, weighed on a precision balance, and suspended above unsaturated salt solutions of known molality in sealed test tubes held at 5 °C. Eighteen solutions were used with water potentials ranging from −0.09 to −4.67 MPa. Once needles had equilibrated with air above the salt solution (8–30 h depending on needle age), they were weighed and oven-dried. Water-release curves were obtained by plotting paired values of needle relative water content and solution water potential. Typically, 35 curves were generated over 3 days compared with 7 curves generated using a pressure chamber over the same period. There was excellent agreement between methods in estimates of elastic modulus, osmotic potential, and apoplastic water content.

scholarly journals Effects of Duration and Temperature in Simulated Dark Shipping on the Subsequent Performance of the Nobile-type Dendrobiums

HortScience ◽  
2013 ◽  
Vol 48 (2) ◽  
pp. 216-221
Author(s):  
Ariningsun P. Cinantya ◽  
Fure-Chyi Chen ◽  
Yao-Chien Alex Chang
Keyword(s):  
Water Content ◽  
Relative Water Content ◽  
Photosynthetic Performance ◽  
Plant Performance ◽  
Long Distance ◽  
Subsequent Performance ◽  
Relative Water ◽  
Flower Diameter ◽  
Leaf Relative Water Content ◽  
Time Required

The popularity of the nobile-type dendrobium (Dendrobium nobile hybrids) has been increasing globally. More information regarding the effects of long-distance shipping, from producing countries to destination market countries, on the post-shipping plant performance is needed. In this study, two nobile-type dendrobium cultivars were subjected to simulated dark shipping (SDS) at various temperatures and durations. Changes in net CO2 uptake rate (Pn), chlorophyll fluorescence, and leaf relative water content after plants had been treated with SDS were investigated. Furthermore, shipped plants were vernalized to investigate the effect of dark shipping on the subsequent flowering quality. Dark shipping for 7 days at 15 °C did not affect the post-shipping photosynthetic performance of D. Lan Tarn Beauty. Increasing the shipping duration from 7 to 21 days increased the time required for Pn recovery from 1 to 12 days. Dendrobium Lan Tarn Beauty recovered its Pn within 4 days when shipped for 21 days at 10 °C, and this was prolonged to 11 days when the plants were shipped at 20 °C. Changes in Fv/Fm indicated that there was no marked damage to either cultivars, and the leaf relative water content was little affected by SDS. Dendrobium Lan Tarn Beauty and D. Lucky Girl shipped at 10 °C flowered 5 and 8 days earlier, respectively, compared with unshipped plants. Regardless of the shipping conditions, shipped D. Lucky Girl had a lower flower diameter and higher total flower count than unshipped plants. No differences were found in the number of nodes with flowers or the total flower count between shipped and unshipped D. Lan Tarn Beauty. Our study suggested that dark shipping for up to 21 days is possible for nobile-type dendrobiums. We recommend shipping temperatures of 10 to 15 °C to reduce the detrimental effects caused by long-term dark shipping.

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