THE RELATION BETWEEN COIL AREA, TEMPERATURE OF COOLING MEDIUM AND DEHYDRATION IN A COLD STORAGE ROOM

1933 ◽  
Vol 8 (1) ◽  
pp. 475-487
Author(s):  
O. C. YOUNG

In studies with a small scale cold storage room of ordinary type a relation was obtained between coil area and temperature of brine for a constant room temperature and given outside conditions. The dehydrating effect in the room was found to decrease as the cooling coil area was increased. As the evaporating area of stored material was increased the dehydration per unit area was found to decrease slightly, and at different temperature levels the dehydration for a constant temperature difference between inside and outside air was found to correspond closely to the capacity of air for holding moisture at the respective temperature levels.

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 949
Author(s):  
Maged Mohammed ◽  
Nashi Alqahtani ◽  
Hamadttu El-Shafie

Dates are subjected to postharvest losses in quality and quantity caused by water loss, fermentation, insect infestation, and microbial spoilage during storage. Cold storage is the main element in the postharvest quality management used for fruit preservation. Although cold storage is used for dates, precision control of the relative humidity (RH) using ultrasonic applications is not used thus far, or it is applied to other fruits on a small scale. Therefore, we designed and constructed an ultrasonic humidifier (DUH) for RH control in the cold storage room (CSR) of dates. The optimum air velocity of 3 m s−1 at the outlets of the DUH ducts produced a mist amount of 6.8 kg h-1 with an average droplet diameter of 4.26 ± 1.43 µm at the applied voltage of 48 V and frequency of 2600 kHz of the transducers. The experimental validation was carried out by comparing a CSR controlled with the DUH with two conventional CSRs. The three tested CSRs were similar in dimensions, cooling system, and amount of stored dates. The time required for cooling 800 kg of dates in the controlled CSR from 25 °C to the target temperature of 5 °C was approximately 48 h. The DUH precisely controlled the RH at the maximum RH set point of 80% in the tested CSR at 5 °C. The controlled RH at 80% has a positive impact on the physicochemical characteristics of the stored dates. It significantly reduced the weight loss of the fruits and preserved fruit mass, moisture content, water activity, firmness, and color parameters. However, no significant effect was observed on fruit dimensions, sphericity, and aspect ratio. The microbial loads of mesophilic aerobic bacteria, molds, and yeasts fell within the acceptable limits in all tested CSRs. Both stored date fruits and artificially infested dates showed no signs of insect activity in the controlled CSR at the temperature of 5 °C and RH of 80%. The DUH proved to be a promising technology for postharvest quality management for dates during cold storage.


2019 ◽  
Vol 7 (2) ◽  
pp. 218
Author(s):  
Nyoman Dhira Prayasa ◽  
I Wayan Widia ◽  
I Made Anom S. Wijaya

Telah dilaksanakan penelitian terkait perancangan dan pembuatan alat distribusi ikan segar menggunakan media pendingin ice pack untuk pedagang ikan keliling. Penelitian dilaksakana bertujuan untuk merancang dan membuat alat distribusi ikan segar yang dapat mempertahankan suhu ikan segar selama transportasi dan penjualan. Penelitian ini terdiri dari dari beberapa tahapan diantaranya identifikasi kebutuhan, perancangan fungsional, perancangan structural dan uji kinerja. Alat distribusi ikan segar yang dibuat tersusun atas ruang penyimpanan ikan, media pendingin ice pack, dan dudukan ruang penyimpanan. Sedangkan untuk pengujian kinerja terdiri dari capaian suhu ruang penyimpanan ikan dalam kondisi kosong, capaian lama waktu alat distribusi ikan dalam mempertahankan suhu rendah ikan, pengukuran nilai Coefficient of Performance (COP), dan penilaian mutu ikan sebelum dan sesudah transportasi dan penjualan dengan uji organoleptik. Hasil pengujian kinerja menunjukkan bahwa capaian suhu terendah ruang penyimpanan ikan adalah -12.30C dengan lama pendinginan hingga batas atas 50C adalah 14.3 jam. Alat distribusi ikan segar yang dibuat dapat mempertahankan suhu rendah ikan dengan batas atas 50C selama 32,03 jam, dengan nilai COP sebesar 0.67.  Berdasarkan uji mutu ikan didapatkan bahwa nilai mutu ikan yang dijual sebelum, setelah transportasi dan setelah penyimpanan adalah 8.0, 7.4, dan 6.2.   Research on fresh fish distribution tool using ice pack as cooling media for small-scale fresh fish retailer was conducted. The research aimed to design fresh fish distribution system for small-scale fresh fish retailer which can maintain the quality of fresh fish during transportation. This research was carried out through several stages, i.e. identification of needs, functional design, structural design and performance test. Fresh fish distribution tool using ice pack as cooling media for fresh fish small-scale retailer consisted fish storage room, fish storage room cover, ice pack, rack and fish storage stand. Performance test was carried out by observing the room temperature of fish storage room in unloaded condition and fish temperature during 4 hours transportation, determining the coefficient of performance (COP) value and observing the fish quality during transportation with organoleptic test. The result showed that the room temperature of fish storage room in unloaded condition could reach -12.30C after 24 minutes operation and maintain temperature with 50C upper limit for 14,3 hours, the distribution tool using ice pack as cooling media could maintain the fish temperature with 50C upper limit for 32.03 hours and organoleptic quality values before transportation, after transportation and after 12 hour storage were 8.0, 7.4, and 6.2. Values of COP was 0.67. This result has fulfilled the requirement of fish quality standard according to national standardization institution.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hai Le-The ◽  
Christian Küchler ◽  
Albert van den Berg ◽  
Eberhard Bodenschatz ◽  
Detlef Lohse ◽  
...  

AbstractWe report a robust fabrication method for patterning freestanding Pt nanowires for use as thermal anemometry probes for small-scale turbulence measurements. Using e-beam lithography, high aspect ratio Pt nanowires (~300 nm width, ~70 µm length, ~100 nm thickness) were patterned on the surface of oxidized silicon (Si) wafers. Combining wet etching processes with dry etching processes, these Pt nanowires were successfully released, rendering them freestanding between two silicon dioxide (SiO2) beams supported on Si cantilevers. Moreover, the unique design of the bridge holding the device allowed gentle release of the device without damaging the Pt nanowires. The total fabrication time was minimized by restricting the use of e-beam lithography to the patterning of the Pt nanowires, while standard photolithography was employed for other parts of the devices. We demonstrate that the fabricated sensors are suitable for turbulence measurements when operated in constant-current mode. A robust calibration between the output voltage and the fluid velocity was established over the velocity range from 0.5 to 5 m s−1 in a SF6 atmosphere at a pressure of 2 bar and a temperature of 21 °C. The sensing signal from the nanowires showed negligible drift over a period of several hours. Moreover, we confirmed that the nanowires can withstand high dynamic pressures by testing them in air at room temperature for velocities up to 55 m s−1.


2019 ◽  
pp. 57-68

“Solo” papaya fruits were harvested in October, 2016 & 2017 seasons from a commercial orchard located in Ismailia Governorate, Egypt. Papaya fruits were harvested at three maturity stages: 25% yellow (stage 1), 50% yellow (stage 2) and 100% yellow (stage 3) and evaluated during storage at ambient temperature (20°C ± 2) for 4 days + at 80- 85% RH or during cold storage at 6°C + 90- 95% RH for 20 days. Papaya fruits softened very rapidly at room temperature after harvest and had 4 days shelf life. However, the fruit can be stored for 20 days at 6°C with little changes in firmness and the fruit apparently progressed in normal ripening upon removal to ambient temperature (20°C) for 3 days. All colour values (a*, L* and C*) were linearly increased during cold storage. Conversely, as a result of colour change from green to orange-red, h° values decreased. Soluble solids content was not affected during ripening at 20°C and remained steady. Fruit harvested at stage 2 and stored at 6°C for 20 days following 3 days at 20°C had superior score for sensorial evaluation.


2020 ◽  
Vol 4 (3) ◽  
pp. 114
Author(s):  
Nazaruddin Nazaruddin ◽  
Teuku Zulfadli ◽  
Andi Mulkan

The environmental temperature has increased significantly reaching 33oC as felt by the community, one of which is in the Aceh region which triggers Global Warming. As a result of the increase in temperature in the Aceh area, many buildings and houses become uncomfortable especially during the daytime because most house with zinc roof. This will cause the temperature in the house and the air around it to increase. Therefore, it is necessary to do research on the study of heat absorption on colored zinc roofs. This research method is to calculate the heat absorption (sun intensity) in zinc that has been coated with several kinds of colors such as white, red, blue, yellow and black. The purpose of this study was to determine the color that has the least amount of heat absorption to the sun's intensity. The highest room temperature on zinc-coated black is 49.2° C and the lowest is in white.  40.9°C from the pen. In the environmental temperature observation, there is the highest temperature at 12.00.  Room temperature increased the highest temperature at 12.00 on black zinc.  The distribution of room temperature can be averaged with a yellow color of 46.0°C, a black color of 49.2°C, a blue of 45.5°C and a white zinc of 40.9 oC.  The heat absorbed in the room is 47.9 joules, so from the overall average of the test it can be described that the room temperature is 45.6 and the zinc temperature is 53.8oC from the highest temperature difference at 12.00 WIB, room temperature and 13.00 WIB the highest absorption occurs at zinc temperature.


Author(s):  
Jakellinye Miranda ◽  
Suélen Braga de Andrade, Andressa Vighi Schiavon ◽  
Pedro Luis Panisson Kaltbach Lemos ◽  
Cláudia Simone Madruga Lima ◽  
Marcelo Barbosa Malgarim

Peach is a climacteric highly-perishable fruit whose post-harvest preservation relies largely on cold storage. The combination of the last with other technologies allows to extend the shelf life of this product. One alternative is the utilization of salicylic acid, a natural compound involved in many physiological phenomena such as resistance against diseases and ripening. Considering these facts, the objective of the present work was to evaluate the effect of pre-harvest application of salicylic acid solutions on the quality of ‘Chimarrita’ peaches during post-harvest cold storage. The experiment was conducted at the Federal University of Pelotas/RS, in the campus of Capão do Leão/RS - Brazil. The application of salicylic acid solutions was performed by direct pulverization on the fruits, 30 days prior to harvest. The concentrations were: 0,0 (control); 1,0; 1,5; and 2,0 mM. After harvest, the fruits were stored in a cold chamber at 1,0 ± 0,5°C and 85-90% RH, for 30 days. The analyses were performed at the following cold storage periods (plus 2 days at room temperature of 20°C to all treatments, in order to simulate commercialization conditions): 10 (+2) days; 20 (+2) days; e 30 (+2) days. The variables evaluated were: mass loss (%); flesh firmness (N); DA index; color (L, a*, b* and hue angle); wooliness incidence (%); rot incidence (%); total soluble solids (°Brix); pH; titrable acidity (% of organic acids); and ratio. The salicylic acid doses and/or the cold storage periods had significant effects on all the evaluated parameters. For most of the parameters analyzed, the intermediate dosis of 1mM (and also 1,5mM) of salicilic acid showed the most promising results. Therefore, the application of salicylic acid solutions 30 days prior to harvest is a technique which can be combined to cold storage in order to shift the quality and the shelf-life of ‘Chimarrita’ peaches.


Foods ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 160
Author(s):  
Francisca Hernández ◽  
Lucía Andreu-Coll ◽  
Andreia Bento-Silva ◽  
Ana Teresa Serra ◽  
Pedro Mena ◽  
...  

This research analyzed the phytochemical profile of prickly pear fruits from ‘Orito’ cultivar stored under cold conditions (2 °C, 85–90% RH) and shelf-life conditions at room temperature (stored at 20 °C for three days after cold storage) for 28 days, mimicking the product life cycle. A total of 18 compounds were identified and quantitated through HPLC-DAD-MS/MS (High-Performance Liquid Chromatographic -Diode Array Detector- Mass Spectrometry) analyses. Phenolic acids such as eucomic acid and betalains such as indicaxanthin were the predominant chemical families, and piscidic acid was the most abundant compound. During cold storage, the content of eucomic acid isomer/derivative and syringaresinol increased, and citric acid decreased, which could be caused by the cold activation of the phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) enzymes. However, no significant differences were found in the content of these compounds during shelf-life storage. These results showed that ‘Orito’ fruit marketability would be possible up to 28 days after harvesting, retaining its profile, which is rich in bioactive compounds.


2021 ◽  
pp. 10-19
Author(s):  
Asnawi Asnawi ◽  
Maskur Maskur ◽  
Adji Santoso Dradjat

The purpose of this study were to compare the quality of spermatozoa stored at 26⁰C, 5⁰C using diluents of NaCl, 10% glucose and 5% glucose. The spermatozoa of a rooster was collected and divided into 6 parts, each 2 tubes diluted in a ratio of 1:1 using NaCl, Glucose5% and Glucose 10%, then each 3 tubes with different diluents were stored at 26⁰C and 5⁰C. Observations of motility, viability and abnormalities of spermatozoa were carried out half an hour, 1 hour after dilution, followed every 2 hours until the ninth hours. The results showed that spermatozoa stored for 9 hours at a temperature of 26⁰C with a physiological diluent of NaCl, 10% Glucose and 5% Glucose each were different (P, < 0.05) with motility 50 ± 0.0%, 42 ± 10.95. % and 34±8.94%, respectively. At storage temperature of 5⁰C for 9 hours, physiological NaCl, 10% glucose and 5% glucose were significantly different (P<0.05) with motility 58.00±10.95%, 46.00±8.94% and 38.00±, respectively. 10.95% in a row. The viability of spermatozoa at 26⁰C storage with 5% glucose diluent was better than 10% glucose and physiological NaCl (P<0.05), 58.93±1.27%, 42.93±1.48% and 33.43±1.27% , while the physiological NaCl diluent and 10% glucose were not significantly different (P>0.05). At 5⁰C storage the viability of spermatozoa in the three diluents was not significantly different, with values of Glucose 10%, Glucose 5% and physiological NaCl 52.57±5.15%, 52.21±5.02% and 48.14±8.09%, respectively. Spermatozoa abnormalities at storage temperature 26⁰C and 5⁰C for 9 hours using physiological NaCl diluent, 5% glucose and 10% glucose, were not significantly different and varied between 5 to 10%. Finally, it can be concluded that at room temperature storage less than 4 hours the quality of spermatozoa was better with 5% glucose diluent, while for cold storage beyond 4 hours the quality of spermatozoa with NaCl diluent was higher


Author(s):  
Sylvain Lamige ◽  
Ce´dric Galizzi ◽  
Jiesheng Min ◽  
Julien Perles ◽  
Fre´de´ric Andre´ ◽  
...  

This study details the influence of reactant temperature on the stability of non-premixed CH4/air co-flow jet flames. Flame characteristics have been studied for five temperature levels (from 295 K to 600 K). The hysteresis zone formed by the limits between attached and lifted flame translates towards higher methane jet velocities with an increase of initial temperature, independently of the air velocity range. Moreover, critical velocities vary linearly with initial temperature. In addition, attachment and lift-off heights have been obtained from CH* chemiluminescence visualization. Results point out that the attachment height decreases significantly with temperature. Observations also indicate that the intrinsic process of lifting is modified. Pre-lifting anchored flame local extinctions, not observed at room-temperature, appear at higher initial temperatures; their occurrence increases with temperature. The lift-off height of turbulent lifted flames is also reduced with temperature. Overall, results show that increasing local temperature in the stabilization zone enhances flame stability.


Sign in / Sign up

Export Citation Format

Share Document