Functional Properties of Glutinous Rice Flour by Dry-Heat Treatment.

Directory of Open Access Journals (Sweden)

Yang Qin

Full Text Available Glutinous rice flour (GRF and glutinous rice starch (GRS were modified by dry-heat treatment and their rheological, thermal properties and freeze-thaw stability were evaluated. Compared with the native GRF and GRS, the water-holding ability of modified GRF and GRS were enhanced. Both the onset and peak temperatures of the modified samples increased while the endothermic enthalpy change decreased significantly (p < 0.05. Meanwhile, dry heating remarkably increased the apparent viscosities of both GRF and GRS. Importantly, compared with GRS samples, the storage modulus (G' and loss modulus (G" values of modified GRF increased more greatly and the tanδ values decreased more remarkably, indicating that the dry-heat treatment showed more impact on the GRF and a higher viscoelasticity compared with GRS. Our results suggest the dry-heat treatment of GRF is a more effective method than that of GRS, which omits the complex and tedious process for purifying GRS, and thereby has more practical applications in the food industry.

Functional Properties of Glutinous Rice Flour by Dry-Heat Treatment.

Science.gov (United States)

Qin, Yang; Liu, Chengzhen; Jiang, Suisui; Cao, Jinmiao; Xiong, Liu; Sun, Qingjie

2016-01-01

Glutinous rice flour (GRF) and glutinous rice starch (GRS) were modified by dry-heat treatment and their rheological, thermal properties and freeze-thaw stability were evaluated. Compared with the native GRF and GRS, the water-holding ability of modified GRF and GRS were enhanced. Both the onset and peak temperatures of the modified samples increased while the endothermic enthalpy change decreased significantly (p < 0.05). Meanwhile, dry heating remarkably increased the apparent viscosities of both GRF and GRS. Importantly, compared with GRS samples, the storage modulus (G') and loss modulus (G") values of modified GRF increased more greatly and the tanδ values decreased more remarkably, indicating that the dry-heat treatment showed more impact on the GRF and a higher viscoelasticity compared with GRS. Our results suggest the dry-heat treatment of GRF is a more effective method than that of GRS, which omits the complex and tedious process for purifying GRS, and thereby has more practical applications in the food industry.

Heat Pump Drying of Fruits and Vegetables: Principles and Potentials for Sub-Saharan Africa

Directory of Open Access Journals (Sweden)

Folasayo Fayose

2016-01-01

Full Text Available Heat pump technology has been used for heating, ventilation, and air-conditioning in domestic and industrial sectors in most developed countries of the world including South Africa. However, heat pump drying (HPD of fruits and vegetables has been largely unexploited in South Africa and by extension to the sub-Saharan African region. Although studies on heat pump drying started in South Africa several years ago, not much progress has been recorded to date. Many potential users view heat pump drying technology as fragile, slow, and high capital intensive when compared with conventional dryer. This paper tried to divulge the principles and potentials of heat pump drying technology and the conditions for its optimum use. Also, various methods of quantifying performances during heat pump drying as well as the quality of the dried products are highlighted. Necessary factors for maximizing the capacity and efficiency of a heat pump dryer were identified. Finally, the erroneous view that heat pump drying is not feasible economically in sub-Saharan Africa was clarified.

Drying of bio fuel utilizing waste heat; Torkning av biobraenslen med spillvaerme

Energy Technology Data Exchange (ETDEWEB)

Johansson, Inge; Larsson, Sara; Wennberg, Olle [S.E.P. Scandinavian Energy Project AB, Goeteborg (Sweden)

2004-10-01

Many industries today have large sources of low grade heat (waste heat), however this energy is mainly lost with effluents to air and water. The aim of this study has been to investigate the technical and economical aspects of utilizing this low grade heat to dry biofuel. The project has been mainly focused towards the forest industry since they have both large amounts of biofuel and waste heat available. Drying of biofuel could generate added revenue (or reduced purchase costs) and through that also create larger incentives for further energy saving modifications to the main process. Due to the higher moisture content together with the risk of frozen bark in the winter time, additional fuels (such as oil) to combust bark in the existing boiler. This is mainly the case when mechanical dewatering is not available. Drying of bark results in an added energy value, which makes it possible to combust the bark without additional fuel. The primary energy demand, in the form of electricity and optional additional heating at load peaks, is low when waste heat is used for the drying process. In this way it is possible to increase the biofuel potential, since the primary energy input to the drying process is essentially lower then the increased energy value of the fuel. Drying also decreases the biological degradation of the fuel. Taking all the above into consideration, waste heat drying could result in a 25 % increase of the biofuel potential in the forest industry in Sweden, without additional cutting of wood. A survey has been done to state which commercial technologies are available for biofuel drying with waste heat. An inquiry was sent out to a number of suppliers and included a few different cases. Relations for approximating investment cost as well as electric power demand were created based on the answers from the inquiry. These relations have then been used in the economical evaluations made for a number of cases representing both sawmills and pulp and paper mills

Exergoeconomic optimization of an ammonia-water hybrid heat pump for heat supply in a spray drying facility

DEFF Research Database (Denmark)

Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars

2014-01-01

Spray drying facilities are among the most energy intensive industrial processes. Using a heat pump to recover waste heat and replace gas combustion has the potential to attain both economic and emissions savings. In the case examined a drying gas of ambient air is heated to 200 XC. The inlet flow...... rate is 100,000 m3/h which yields a heat load of 6.1 MW. The exhaust air from the drying process is 80 XC. The implementation of an ammonia-water hybrid absorption-compression heat pump to partly cover the heat load is investigated. A thermodynamic analysis is applied to determine optimal circulation...... ratios for a number of ammonia mass fractions and heat pump loads. An exergoeconomic optimization is applied to minimize the lifetime cost of the system. Technological limitations are applied to constrain the solution to commercial components. The best possible implementation is identified in terms...

The effects of drying following heat shock exposure of the desert moss Syntrichia caninervis.

Science.gov (United States)

Xu, Shu-Jun; Liu, Chun-Jiang; Jiang, Ping-An; Cai, Wei-Min; Wang, Yan

2009-03-15

Desert mosses are components of biological soil crusts (BSCs) and their ecological functions make assessment and protection of these mosses a high-ranking management priority in desert regions. Drying is thought to be useful for desert mosses surviving heat shock. In this study, we investigated the role of drying by monitoring the responses of physiological characters and asexual reproduction in the typical desert moss Syntrichia caninervis. Heat significantly decreased chlorophyll content and weakened rapid recovery of photochemical activity, and increased carotenoid content and membrane permeability. Lethal temperatures significantly destroyed shoot regeneration potential. In comparison with heat alone, drying significantly increased protonema emergence time and depressed protonema emergence area. Drying combined with heat accelerated water loss, followed by a decrease of photosynthetic activity. Drying had different influences on membrane permeability at different temperatures. When moss leaves were subjected to a combined stress of drying and heat shock, photosynthesis was maintained mainly due to the effects of drying on physiological activity although the cellular morphological integrity was affected. Drying caused opposing effects on moss physiological and reproductive characteristics. On the one hand, drying caused a positive synergistic effect with heat shock when the temperature was below 40 degrees C. On the other hand, drying showed antagonism with heat shock when the moss was subjected to temperatures higher than 40 degrees C. These findings may help in understanding the survival mechanism of dessert mosses under heat shock stress which will be helpful for the artificial reconstruction of BSCs.

The effects of drying following heat shock exposure of the desert moss Syntrichia caninervis

International Nuclear Information System (INIS)

Xu Shujun; Liu Chunjiang; Jiang Pingan; Cai Weimin; Wang Yan

2009-01-01

Desert mosses are components of biological soil crusts (BSCs) and their ecological functions make assessment and protection of these mosses a high-ranking management priority in desert regions. Drying is thought to be useful for desert mosses surviving heat shock. In this study, we investigated the role of drying by monitoring the responses of physiological characters and asexual reproduction in the typical desert moss Syntrichia caninervis. Heat significantly decreased chlorophyll content and weakened rapid recovery of photochemical activity, and increased carotenoid content and membrane permeability. Lethal temperatures significantly destroyed shoot regeneration potential. In comparison with heat alone, drying significantly increased protonema emergence time and depressed protonema emergence area. Drying combined with heat accelerated water loss, followed by a decrease of photosynthetic activity. Drying had different influences on membrane permeability at different temperatures. When moss leaves were subjected to a combined stress of drying and heat shock, photosynthesis was maintained mainly due to the effects of drying on physiological activity although the cellular morphological integrity was affected. Drying caused opposing effects on moss physiological and reproductive characteristics. On the one hand, drying caused a positive synergistic effect with heat shock when the temperature was below 40 deg. C. On the other hand, drying showed antagonism with heat shock when the moss was subjected to temperatures higher than 40 deg. C. These findings may help in understanding the survival mechanism of dessert mosses under heat shock stress which will be helpful for the artificial reconstruction of BSCs

Hot dry rock heat mining

International Nuclear Information System (INIS)

Duchane, D.V.

1992-01-01

Geothermal energy utilizing fluids from natural sources is currently exploited on a commercial scale at sites around the world. A much greater geothermal resource exists, however, in the form of hot rock at depth which is essentially dry. This hot dry rock (HDR) resource is found almost everywhere, but the depth at which usefully high temperatures are reached varies from place to place. The technology to mine the thermal energy from HDR has been under development for a number of years. Using techniques adapted from the petroleum industry, water is pumped at high pressure down an injection well to a region of usefully hot rock. The pressure forces open natural joints to form a reservoir consisting of a small amount of water dispensed in a large volume of hot rock. This reservoir is tapped by second well located at some distance from the first, and the heated water is brought to the surface where its thermal energy is extracted. The same water is then recirculated to mine more heat. Economic studies have indicated that it may be possible to produce electricity at competitive prices today in regions where hot rock is found relatively close to the surface

High-frequency and microwave heating as a pretreatment to kiln drying of hollowed-out timber

International Nuclear Information System (INIS)

Yamada, N.; Okumura, S.; Taniguchi, Y.

2001-01-01

To dry hollowed-out timber without V-shaped drying checks, its inner part should be dried faster than the outer part. The feasibility of high frequency heating and microwave heating as a pretreatment of kiln drying of hollow timber was examined. During high frequency heating, the top and bottom parts of the timber were dried faster than the right and left parts because the central hollow acts as an air-gap. The outer part dried faster than the inner part during microwave heating, probably because of insufficient penetration of microwave energy into the inner part. The uneven heating of hollowed timber was improved by turning the specimen around its axis during high frequency heating and by setting the specimen upright in the microwave oven

Comparison of dehumidification and heat and vent drying of hem-fir softwood

Energy Technology Data Exchange (ETDEWEB)

Mackay, J F.G.; Nielson, R W

1988-03-01

The objective of this project was to demonstrate the performance of dehumidifier kilns, compared to gas-fired, hot-air kilns in drying a commercial grade of softwood lumber. To accomplish this, drying tests were conducted with matched loads of lumber in a new test facility which was constructed to operate as a conventional heat and vent kiln or as a dehumidifier kiln. Comparisons were made of drying times, shrinkage and quality of dried product and total drying energy consumptions. Data from these tests were used in conjunction with capital, energy and other costs obtained from suppliers and operators of existing kilns to make economic comparisons between commercial-sized dehumidifier and heat and vent kilns. These comparisons were made on the basis of equivalent uniform annual costs. Dehumidification drying took about 20% longer and used about 50% of energy compared to heat and vent drying. Analysis of the test runs indicated that further improvements in the energy utilization efficiencies of dehumidifier kilns are feasible since one run indicated an energy consumption of only 36% of that in heat and vent drying. No differences in shrinkage or degrade were apparent. Economic comparisons for three sizes of kilns showed total drying costs by dehumidification to be less for a small-size kiln but more for medium- and large-size operations. Sensitivity analyses were performed to observe the effect of alternate energy prices, dehumidifier energy consumptions, dehumidifier drying times, building costs and degrade. 9 refs., 7 figs., 36 tabs.

An Internally Heated Shape Memory Polymer Dry Adhesive

Directory of Open Access Journals (Sweden)

Jeffrey Eisenhaure

2014-08-01

Full Text Available A conductive epoxy-based shape memory polymer (SMP is demonstrated using carbon black (CB as a dopant for the purpose of creating an SMP dry adhesive system which can internally generate the heat required for activation. The electrical and mechanical properties of the CB/SMP blends for varying dopant concentrations are characterized. A composite adhesive is created to minimize surface contact resistance to conductive tape acting as electrodes, while maintaining bulk resistivity required for heat generation due to current flow. The final adhesive can function on flat or curved surfaces. As a demonstration, a 25 mm wide by 45 mm long dry adhesive strip is shown to heat evenly from an applied voltage, and can easily hold a mass in excess of 6 kg when bonded to a spherical concave glass surface using light pressure at 75 °C.

A Novel Parabolic Trough Concentrating Solar Heating for Cut Tobacco Drying System

Directory of Open Access Journals (Sweden)

Jiang Tao Liu

2014-01-01

Full Text Available A novel parabolic trough concentrating solar heating for cut tobacco drying system was established. The opening width effect of V type metal cavity absorber was investigated. A cut tobacco drying mathematical model calculated by fourth-order Runge-Kutta numerical solution method was used to simulate the cut tobacco drying process. And finally the orthogonal test method was used to optimize the parameters of cut tobacco drying process. The result shows that the heating rate, acquisition factor, and collector system efficiency increase with increasing the opening width of the absorber. The simulation results are in good agreement with experimental data for cut tobacco drying process. The relative errors between simulated and experimental values are less than 8%, indicating that this mathematical model is accurate for the cut tobacco airflow drying process. The optimum preparation conditions are an inlet airflow velocity of 15 m/s, an initial cut tobacco moisture content of 26%, and an inlet airflow temperature of 200°C. The thermal efficiency of the dryer and the final cut tobacco moisture content are 66.32% and 14.15%, respectively. The result shows that this parabolic trough concentrating solar heating will be one of the heat recourse candidates for cut tobacco drying system.

Development of drying equipment for heat sensitive material : final report

Energy Technology Data Exchange (ETDEWEB)

Schoenau, G.J.; Sokhansanj, S. [Saskatchewan Univ., Saskatoon, SK (Canada)

2003-07-01

This paper described a project in which two types of prototype heat pump dryer systems were designed, constructed and field tested in 2000 to 2002. Performance testing was accomplished through a computer based simulation model for predicting dryer performance. The paper describes the procedures followed and the results obtained. The dryer is used for high value specialty crops such as ginseng, herbs and echinacea which require low temperature drying. The heat pump dryer operates under a closed loop and can dry these crops at low temperatures, independent of ambient conditions. The first prototype was a small fixed bed cabinet dryer suitable for small growers. The other was a full scale prototype moving bed cross flow system suitable for large scale commercial drying of sensitive agricultural crops. The heat pump system is faster and more energy efficient than conventional dryers. The average moisture content of ginseng roots was reduced by 10 per cent in 5 days using 190 kWh of energy. The heat pump dryer is 22 per cent more efficient than a conventional dryer due to its recirculating system. Drying time is reduced by 65 per cent. A computerized simulation validated experimental results. 30 refs., 10 tabs., 29 figs.

Hybrid heat pipe based passive cooling device for spent nuclear fuel dry storage cask

International Nuclear Information System (INIS)

Jeong, Yeong Shin; Bang, In Cheol

2016-01-01

Highlights: • Hybrid heat pipe was presented as a passive cooling device for dry storage cask of SNF. • A method to utilize waste heat from spent fuel was suggested using hybrid heat pipe. • CFD analysis was performed to evaluate the thermal performance of hybrid heat pipe. • Hybrid heat pipe can increase safety margin and storage capacity of the dry storage cask. - Abstract: Conventional dry storage facilities for spent nuclear fuel (SNF) were designed to remove decay heat through the natural convection of air, but this method has limited cooling capacity and a possible re-criticality accident in case of flooding. To enhance the safety and capacity of dry storage cask of SNF, hybrid heat pipe-based passive cooling device was suggested. Heat pipe is an excellent passive heat transfer device using the principles of both conduction and phase change of the working fluid. The heat pipe containing neutron absorber material, the so-called hybrid heat pipe, is expected to prevent the re-criticality accidents of SNF and to increase the safety margin during interim and long term storage period. Moreover, a hybrid heat pipe with thermoelectric module, a Stirling engine and a phase change material tank can be used for utilization of the waste heat as heat-transfer medium. Located at the guide tube or instrumentation tube, hybrid heat pipe can remove decay heat from inside the sealed metal cask to outside, decreasing fuel rod temperature. In this paper, a 2-step analysis was performed using computational fluid dynamics code to evaluate the heat and fluid flow inside a cask, which consisted of a single spent fuel assembly simulation and a full-scope dry cask simulation. For a normal dry storage cask, the maximum fuel temperature is 290.0 °C. With hybrid heat pipe cooling, the temperature decreased to 261.6 °C with application of one hybrid heat pipe per assembly, and to 195.1 °C with the application of five hybrid heat pipes per assembly. Therefore, a dry

Process and apparatus for indirect-fired heating and drying

Science.gov (United States)

Abbasi, Hamid Ali; Chudnovsky, Yaroslav

2005-04-12

A method for heating flat or curved surfaces comprising injecting fuel and oxidant along the length, width or longitudinal side of a combustion space formed between two flat or curved plates, transferring heat from the combustion products via convection and radiation to the surface being heated on to the material being dried/heated, and recirculating at least 20% of the combustion products to the root of the flame.

Method of extracting heat from dry geothermal reservoirs

Science.gov (United States)

Potter, R.M.; Robinson, E.S.; Smith, M.C.

1974-01-22

Hydraulic fracturing is used to interconnect two or more holes that penetrate a previously dry geothermal reservoir, and to produce within the reservoir a sufficiently large heat-transfer surface so that heat can be extracted from the reservoir at a usefully high rate by a fluid entering it through one hole and leaving it through another. Introduction of a fluid into the reservoir to remove heat from it and establishment of natural (unpumped) convective circulation through the reservoir to accomplish continuous heat removal are important and novel features of the method. (auth)

[Benefit of microwaves in case of heat-sensitive agglomerate drying].

Science.gov (United States)

Kelen, Akos; Hegedüs, Agota; Nagy, Tibor; Máthé, Zoltán; Hódi, Klára

2003-01-01

The microwave assisted vacuum drying of heat-sensitive materials is increasing in the pharmaceutical industry since the eighties. This paper deals with results of two experiment series obtained on a laboratory scale single pot dryer (Collette Ultima 251). Firstly water was heated up to the boiling point exclusively by predetermined microwave energy and then by various wall temperatures in order to determine the convection efficiency of the system. The experiments were carried out at fixed pressure level (80 mbar) and with optimum bowl load (15 kg). According to the demonstrated idea each single pot system efficiency can be specified at any type and quantity of load. With the help of the presented results the second experiments were designed to compare the microwave and convection efficiency of the single pot system during granule drying. A placebo granule was dried either by an exclusive convection or microwave method up to the determined LOD (< 0.5%). According to the tests extreme high wall temperature (85 degrees C) had to be used to achieve the same drying time--and efficiency--as with the usage of dielectric heating. Based on the results it can be stated that the shorter drying time under favourable conditions is the advantage of microwave radiation over the conventional technique.

Wood chip drying in connection with combined heat and power or solar energy in Finland

Directory of Open Access Journals (Sweden)

Rinne Samuli

2014-01-01

Full Text Available 20% of the Finnish district heating (DH power plant fuels are wood-based and the share is increasing. The wood fuel demand probably exceeds the potential supply in the future. The wood fuel drying with waste heat is one profitable opportunity to gain more wood fuel. If the drying energy can be produced with lower primary energy use than combusting the fuel directly, the drying potentially improves the system efficiency. In this study, the drying feasibility in the connection of a combined heat and power (CHP system, possibly with solar collectors, is calculated. The wood fuel heating can be increased profitably by 6%, using the heat from CHP for drying only when the marginal cost of the heat is low enough, i.e. the electricity price is high enough and there is free capacity after the DH demand. Although the drying is profitable, a larger heat storage can also increase the annual result similarly. The best investment choice depends on the plant properties. Here the optimal system enables 20% DH production cost savings. Solar heat may be profitable, when the solar heat has a 2–3% share of the annual heat demand. However, the dryer or larger storage tank are more profitable investments.

Coffee husk associated with firewood as fuel for indirect heating of drying air

Energy Technology Data Exchange (ETDEWEB)

Magalhaes, Edney Alves; Silva, Juarez de Sousa e; Silva, Jadir Nogueira da; Oliveira Filho, Delly [Universidade Federal de Vicosa (DEA/UFV), MG (Brazil). Dept. de Engenharia Agricola; Donzeles, Sergio Mauricio Lopes [Empresa de Pesquisa Agropecuaria de Minas Gerais (EPAMIG), Vicosa, MG (Brazil)

2008-07-01

The objective of this work was the performance analysis of a furnace, burning coffee husk associated with firewood to heat the drying air passing through a heat exchanger. For the analysis the temperature variation, the combustion quality, the heat losses and the furnace thermal efficiency were all monitored. Results showed that the furnace average efficiency was 58.3% and the heat losses in the exhaust were 24.3%. The presence of carbon monoxide in the exhaust gases (average 2982.8 ppm) had proven incomplete combustion, and suggesting that the combustion gases can not be used to directly drying of foods. Despite of indirect heating, the presented thermal efficiency indicates that the burning of coffee husks is one economic alternative for air heating in grain drying or in other agricultural processes. (author)

Heat and Mass Transfer Model in Freeze-Dried Medium

Science.gov (United States)

Alfat, Sayahdin; Purqon, Acep

2017-07-01

There are big problems in agriculture sector every year. One of the major problems is abundance of agricultural product during the peak of harvest season that is not matched by an increase in demand of agricultural product by consumers, this causes a wasted agricultural products. Alternative way was food preservation by freeze dried method. This method was already using heat transfer through conduction and convection to reduce water quality in the food. The main objective of this research was to design a model heat and mass transfer in freeze-dried medium. We had two steps in this research, the first step was design of medium as the heat injection site and the second was simulate heat and mass transfer of the product. During simulation process, we use physical property of some agriculture product. The result will show how temperature and moisture distribution every second. The method of research use finite element method (FEM) and will be illustrated in three dimensional.

Microwave blanching and drying characteristics of Centella asiatica (L.) urban leaves using tray and heat pump-assisted dehumidified drying.

Science.gov (United States)

Trirattanapikul, W; Phoungchandang, S

2014-12-01

The appropriate stage of maturity of Centella asiatica (L.) Urban leaves was investigated. Mature leaves with large diameter contained high total phenolics and % inhibition. Microwave blanching for 30 s retained the highest total phenolics and the microwave blanching for 30 s and 45 s retained the highest % inhibition. Modified Henderson and Modified Chung-Pfost models showed the best fit to both fresh and blanched leaves for equilibrium moisture content, Xe = f(RHe, T) and equilibrium relative humidity, RHe = f(Xe, T), respectively. The Modified Page model was the most effective model in describing the leaf drying. All drying was in the falling rate period. The drying constant was related to drying air temperature using the Arrhenius model. Effective moisture diffusivities increased with increasing temperature and blanching treatments as well as dehumidification by heat pump-assisted dehumidified dryer. The heat pump-assited dehumidified drying incorporated by the microwave blanching could reduce the drying time at 40 °C by 31.2 % and increase % inhibition by 6.1 %. Quality evaluation by total phenolics, % inhibition and rehydration ratio showed the best quality for C. asiatica leaves pretreated by microwave blanching and dried at 40 °C in heat pump-assisted dehumidified dryer.

Drying apparatus with catalytic combustion of the exhaust gases and with heat recovery

Energy Technology Data Exchange (ETDEWEB)

Betz, E C

1975-11-20

The invention applies to a drying kiln whose charge is dried by a heating gas flow. In order to conserve energy, the thermal energy is transferred back from the catalytically oxydized exhaust gas flow to the heating gas flow. This is done by means of a heat exchanger which contains a heat transfer liquid whose pressure is set to make its boiling temperature the same as the maximum permissible heating gas temperature. The fuel supply to the heating gas burner is controlled by a temperature sensor across a control mechanism.

Enhanced Thermal Management System for Spent Nuclear Fuel Dry Storage Canister with Hybrid Heat Pipes

International Nuclear Information System (INIS)

Jeong, Yeong Shin; Bang, In Cheol

2016-01-01

Dry storage uses the gas or air as coolant within sealed canister with neutron shielding materials. Dry storage system for spent fuel is regarded as relatively safe and emits little radioactive waste for the storage, but it showed that the storage capacity and overall safety of dry cask needs to be enhanced for the dry storage cask for LWR in Korea. For safety enhancement of dry cask, previous studies of our group firstly suggested the passive cooling system with heat pipes for LWR spent fuel dry storage metal cask. As an extension, enhanced thermal management systems for the spent fuel dry storage cask for LWR was suggested with hybrid heat pipe concept, and their performances were analyzed in thermal-hydraulic viewpoint in this paper. In this paper, hybrid heat pipe concept for dry storage cask is suggested for thermal management to enhance safety margin. Although current design of dry cask satisfies the design criteria, it cannot be assured to have long term storage period and designed lifetime. Introducing hybrid heat pipe concept to dry storage cask designed without disrupting structural integrity, it can enhance the overall safety characteristics with adequate thermal management to reduce overall temperature as well as criticality control. To evaluate thermal performance of hybrid heat pipe according to its design, CFD simulation was conducted and previous and revised design of hybrid heat pipe was compared in terms of temperature inside canister

Production of dry wood chips in connection with a district heating plant

Directory of Open Access Journals (Sweden)

Yrjölä Jukka

2004-01-01

Full Text Available Moisture and its variation in wood chips make the control of burning in small scale heating appliances difficult resulting in emissions and loss of efficiency. If the quality of wood chips would be better, i. e. dried and sieved fuel with more uniform size distribution would be avail able, the burning could be much cleaner and efficiency higher. In addition higher power out put could be obtained and the investment costs of the burning appliances would be lower. The production of sieved and dried wood chip with good quality could be accomplished in connection with a district heating plant. Then the plant would make profit, in addition to the district heat, from the dried wood chips sold to the neighboring buildings and enterprises sep a rated from the district heating net using wood chips in energy production. The peak power of a district heating plant is required only a short time during the coldest days of the winter. Then the excess capacity during the milder days can be used as heat source for drying of wood chips to be marketed. Then wood chips are sieved and the fuel with best quality is sold and the reject is used as fuel in the plant it self. In a larger district heating plant, quality of the fuel does not need to be so high In this paper the effect of moisture on the fuel chain and on the boiler is discussed. Energy and mass balance calculations as a tool of system design is described and the characteristics of proposed dry chips production method is discussed.

Practical use of solar heating-dehumidification dry kiln

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Yoshinori

1988-06-01

In order to decrease the energy cost for drying, a solar-dehumidification dry kiln which used the dehumidification dry process together with the solar thermal drier was developed and tested. In the daytime the drying temperature rose up to 60/sup 0/C in summer and 40/sup 0/C in winter, and it was kept higher by 15 to 20/sup 0/C than the outside temperature at night. Owing to the adoption of the combination of direct solar heating and exhausting highly humid air, it was not necessary to operate the dry kiln in the day time. Average electrical energy consumption which was consumed to 15% moisture content from the raw lumber was about 73kWh/m/sup 3/ in summer which was lowest, about 87kWh/m/sup 3/ in winter. Energy cost required for the solar dehumidification dry kiln is 1/2 to 2/3 of that of the conventional dehumidification dry kiln. The solar-dehumidification dry kiln has a merit of cheaper operating cost in the low energy cost and reduced drying time. (7 figs, 1 tab, 6 refs)

Determination of Sliced Pineapple Drying Characteristics in A Closed Loop Heat Pump Assisted Drying System

Directory of Open Access Journals (Sweden)

Cüneyt Tunçkal

2018-02-01

Full Text Available Pineapple (Ananascomosus slices were dried with the aid of a heat pump assisted dryer (HPD. During this process, air velocity was kept constant at 1m/s, while air temperatures were changed as 37°C, 40°C and 43°C. The drying air was also circulated by using an axial fan in a closed cycle and fresh air was not allowed into the system. The drying rate and drying time were significantly influenced by drying temperature. It was observed that drying temperatures had significant effects on the drying rate and drying time. During the conduct of the study, pineapple slices were dried at 37, 40 and 43°C for 465, 360 and 290 min, respectively. The specific moisture extraction ratio (SMER values were observed to change as drying temperatures were changed. The drying rate curves indicated that the whole drying process occurred in the falling rate period. Seven well-known thin-layer models (Lewis, Henderson &Pabis, Logarithmic, Page, Midilli & Kucuk, Weibull and Aghbashlo et al. were employed to make a prediction about drying kinetics through nonlinear regression analysis. The Midilli & Kucuk and Aghbashlo et al. models were consistent with the experimental data. Fick’s second law of diffusion was used to determine the moisture diffusivity coefficient ranging from 3.78×10–9 to 6.57×10-9  m2/s the each of the above mentioned temperatures. The dependence of effective diffusivity coefficient on temperature was defined by means a fan Arrhenius type equation. The activation energy of moisture diffusion was found to be 75.24kJ/mol.   Article History: Received: July 18th 2017; Received: October 27th 2017; Accepted: January 16th 2018; Available online How to Cite This Article: Tunçkal, C., Coşkun, S., Doymaz, I. and Ergun, E. (2018 Determination of Sliced Pineapple Drying Characteristics in A Closed Loop Heat Pump Assisted Drying System. International Journal of Renewable Energy Development, 7(1, 35-41. https://doi.org/10.14710/ijred.7.1.35-41

Evaluation of Heat Flux Measurement as a New Process Analytical Technology Monitoring Tool in Freeze Drying.

Science.gov (United States)

Vollrath, Ilona; Pauli, Victoria; Friess, Wolfgang; Freitag, Angelika; Hawe, Andrea; Winter, Gerhard

2017-05-01

This study investigates the suitability of heat flux measurement as a new technique for monitoring product temperature and critical end points during freeze drying. The heat flux sensor is tightly mounted on the shelf and measures non-invasively (no contact with the product) the heat transferred from shelf to vial. Heat flux data were compared to comparative pressure measurement, thermocouple readings, and Karl Fischer titration as current state of the art monitoring techniques. The whole freeze drying process including freezing (both by ramp freezing and controlled nucleation) and primary and secondary drying was considered. We found that direct measurement of the transferred heat enables more insights into thermodynamics of the freezing process. Furthermore, a vial heat transfer coefficient can be calculated from heat flux data, which ultimately provides a non-invasive method to monitor product temperature throughout primary drying. The end point of primary drying determined by heat flux measurements was in accordance with the one defined by thermocouples. During secondary drying, heat flux measurements could not indicate the progress of drying as monitoring the residual moisture content. In conclusion, heat flux measurements are a promising new non-invasive tool for lyophilization process monitoring and development using energy transfer as a control parameter. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Drying characteristics of rough rice by far-infrared radiation heating

International Nuclear Information System (INIS)

Matsuoka, T.

1990-01-01

The relationship between the heat radiation characteristics of a far-infrared radiation heater and the drying characteristics of rough rice was investigated to determine the basic data required for utilization of far-infrared rays for drying rough rice. Results of investigations are discussed in detail

Heat transfer investigations within dry spent fuel casks

International Nuclear Information System (INIS)

Nitsche, F.

1986-07-01

For studying the heat transfer processes and predicting the maximum spent fuel element surface temperature in a spent fuel assembly (SFA) transported in a dry cask, model experiments have been performed with a gas-filled model cask containing a simplified electrically heated model of a WWER-type SFA with 90 fuel elements. The temperature distribution of the SFA model is measured for different heat rates under vacuum in the model cask, and under normal pressure and overpressure (0.1 ... 0.7 MPa) for several cooling gases (air, argon, helium) in order to separately investigate heat transfer processes by radiation and convection/conduction. The measuring results were compared with the calculations. Computer programmes as well as simplified calculation methods for temperature prediction were developed and checked. The results obtained are also useful for thermal analyses in the field of the dry storage of SFAs in a cask or can. Specifically it was found that: The heat removal from the SFA can be considerably improved by increasing the internal cask pressure or by using helium as coolant. The radiant heat exchange in the SFA model can be calculated with sufficient accuracy by means of a computer programme developed in 1978 or by means of a simplified analytical representation shown in the final report. Both methods are directly applicable to the original SFA and useful in order to approximately calculate the maximum SFE surface temperature under normal pressure, if the fraction of heat transferred by radiation is allowed for. For the calculation of the total heat transfer a computer programme was developed and verified, which completely permits the temperature prediction of the SFA model in dependence on heat rate, type of gaseous coolant and coolant pressure. This computer programme can be directly applied to the original SFA for the calculation of the maximum SFE surface temperature

Nanoscale Structural and Mechanical Analysis of Bacillus anthracis Spores Inactivated with Rapid Dry Heating

Science.gov (United States)

Felker, Daniel L.; Burggraf, Larry W.

2014-01-01

Effective killing of Bacillus anthracis spores is of paramount importance to antibioterrorism, food safety, environmental protection, and the medical device industry. Thus, a deeper understanding of the mechanisms of spore resistance and inactivation is highly desired for developing new strategies or improving the known methods for spore destruction. Previous studies have shown that spore inactivation mechanisms differ considerably depending upon the killing agents, such as heat (wet heat, dry heat), UV, ionizing radiation, and chemicals. It is believed that wet heat kills spores by inactivating critical enzymes, while dry heat kills spores by damaging their DNA. Many studies have focused on the biochemical aspects of spore inactivation by dry heat; few have investigated structural damages and changes in spore mechanical properties. In this study, we have inactivated Bacillus anthracis spores with rapid dry heating and performed nanoscale topographical and mechanical analysis of inactivated spores using atomic force microscopy (AFM). Our results revealed significant changes in spore morphology and nanomechanical properties after heat inactivation. In addition, we also found that these changes were different under different heating conditions that produced similar inactivation probabilities (high temperature for short exposure time versus low temperature for long exposure time). We attributed the differences to the differential thermal and mechanical stresses in the spore. The buildup of internal thermal and mechanical stresses may become prominent only in ultrafast, high-temperature heat inactivation when the experimental timescale is too short for heat-generated vapor to efficiently escape from the spore. Our results thus provide direct, visual evidences of the importance of thermal stresses and heat and mass transfer to spore inactivation by very rapid dry heating. PMID:24375142

Triangularly arranged heat exchanger bundles to restrain wind effects on natural draft dry cooling system

International Nuclear Information System (INIS)

Liao, H.T.; Yang, L.J.; Du, X.Z.; Yang, Y.P.

2016-01-01

Highlights: • Triangularly arranged heat exchanger around the dry-cooling tower is proposed. • By coupling condenser with dry cooling system, TACHE performance is obtained. • At low wind speeds, cooling performance with TACHE is inferior to that with CACHE. • Better performance can be achieved for cooling system with TACHE at high wind speeds. • TACHE can be applied to the region with the strong prevailing wind all year around. - Abstract: It has been commonly recognized that the crosswind may deteriorate the cooling performance of the natural draft dry cooling system with vertically arranged heat exchanger bundles around the circumference of dry-cooling tower. With the purpose for restraining the adverse effects of ambient winds, a novel triangular configuration of heat exchanger bundles is proposed in this work. The air-side flow and heat transfer models coupled with the circulating water heat transfer process are developed for two kinds of natural draft dry cooling systems with the conventional circularly arranged and novel triangularly arranged heat exchanger bundles, by which the flow and temperature fields, mass flow rate of cooling air, outlet water temperature of heat exchanger and turbine back pressure are obtained. Three wind directions of 0°, 90°, and 180° are investigated at various wind speeds for the natural draft dry cooling system with triangularly arranged heat exchanger bundles, which are compared with the conventional system with circularly arranged heat exchanger bundles. The results show that the thermo-flow performances of the natural draft dry cooling system with triangularly arranged heat exchanger get improved significantly at high wind speeds and in the wind direction of 180°, thus a low turbine back pressure can be achieved, which is of benefit to the energy efficiency of the power generating unit. The natural draft dry cooling system with triangularly arranged heat exchanger is recommended to apply to the regions with

Dry heat tolerance of the dry colony in Nostoc sp. HK-01 for useful usage in space agriculture

Science.gov (United States)

Kimura, Shunta; Tomita-Yokotani, Kaori; Yamashita, Masamichi; Sato, Seigo; Katoh, Hiroshi

Space agriculture producing foods is important as one of approach for space habitation. Nostoc sp. HK-01 is one of terrestrial cyanobacterium having a high dry tolerance and it has several ability, photosynthesis, nitrogen fixation and usefulness as a food, it is thought that it can be used for space agriculture. Besides, a study on each tolerance predicted at the time of introduction to space agriculture is necessary. Therefore, as one of the tolerance that are intended to space environment, dry heat ( 100(°) C, 10 h ) tolerance of dry colony in Nostoc sp. HK-01 has been investigated, but the detail function of them has not yet been elucidated. We focused on the extracellular polysaccharides ( EPS ) having the various tolerance, desiccation, low temperature, NaCl, and heavy particle beam. We will consider the function and useful usage of this cyanobacterum in space agriculture after the consideration of the results of contribution of the possibility that EPS improves dry heat tolerance under a dry condition.

Utilization of geothermal heat in tropical fruit-drying process

Energy Technology Data Exchange (ETDEWEB)

Chen, B.H.; Lopez, L.P.; King, R.; Fujii, J.; Tanaka, M.

1982-10-01

The power plant utilizes only the steam portion of the HGP-A well production. There are approximately 50,000 pounds per hour of 360/sup 0/F water produced (approximately 10 million Btu per hour) and the water is currently not used and is considered a waste. This tremendous resource could very well be used in applications such as food processing, food dehydration and other industrial processing that requires low-grade heat. One of the applications is examined, namely the drying of tropical fruits particularly the papaya. The papaya was chosen for the obvious reason that it is the biggest crop of all fruits produced on the Big Island. A conceptual design of a pilot plant facility capable of processing 1000 pounds of raw papaya per day is included. This facility is designed to provide a geothermally heated dryer to dehydrate papayas or other tropical fruits available on an experimental basis to obtain data such as drying time, optimum drying temperature, etc.

PBMR spent fuel bulk dry storage heat removal - HTR2008-58170

International Nuclear Information System (INIS)

De Wet, G. J.; Dent, C.

2008-01-01

A low decay heat (implying Spent Fuel (SF) pebbles older than 8-9 years) bulk dry storage section is proposed to supplement a 12-tank wet storage section. Decay heat removal by passive means must be guaranteed, taking into account the fact that dry storage vessels are under ground and inside the building footprint. Cooling takes place when ambient air (drawn downwards from ground level) passes on the outside of the 6 tanks' vessel containment (and gamma shielding), which is in a separate room inside the building, but outside PBMR building confinement and open to atmosphere. Access for loading/unloading of SF pebbles is only from the top of a tank, which is inside PBMR building confinement. No radioactive substances can therefore leak into atmosphere, as vessel design will take into account corrosion allowance. In this paper, it is shown (using CFD (Computational Fluid Dynamics) modelling and analytical analyses) that natural convection and draught induced flow combine to remove decay heat in a self-sustaining process. Decay heat is the energy source, which powers the draught inducing capability of the dry storage modular cell system: the more decay heat, the bigger the drive to expel heated air through a higher outlet and entrain cool ambient air from ground level to the bottom of the modular cell. (authors)

Tropical Drosophila ananassae of wet-dry seasons show cross resistance to heat, drought and starvation

Directory of Open Access Journals (Sweden)

Chanderkala Lambhod

2017-11-01

Full Text Available Plastic responses to multiple environmental stressors in wet or dry seasonal populations of tropical Drosophila species have received less attention. We tested plastic effects of heat hardening, acclimation to drought or starvation, and changes in trehalose, proline and body lipids in Drosophila ananassae flies reared under wet or dry season-specific conditions. Wet season flies revealed significant increase in heat knockdown, starvation resistance and body lipids after heat hardening. However, accumulation of proline was observed only after desiccation acclimation of dry season flies while wet season flies elicited no proline but trehalose only. Therefore, drought-induced proline can be a marker metabolite for dry-season flies. Further, partial utilization of proline and trehalose under heat hardening reflects their possible thermoprotective effects. Heat hardening elicited cross-protection to starvation stress. Stressor-specific accumulation or utilization as well as rates of metabolic change for each energy metabolite were significantly higher in wet-season flies than dry-season flies. Energy metabolite changes due to inter-related stressors (heat versus desiccation or starvation resulted in possible maintenance of energetic homeostasis in wet- or dry-season flies. Thus, low or high humidity-induced plastic changes in energy metabolites can provide cross-protection to seasonally varying climatic stressors.

Solar water heating and its prospect for timber drying application

Energy Technology Data Exchange (ETDEWEB)

Yin, B T

1982-01-01

The technical requirements for timber drying are discussed, and the possibility of using a solar water heating system to substitute for conventional fuel in a modern kiln is looked into from heat transfer considerations. At the moment, conventional fuel is used to generate steam for the heating of air in a kiln. If hot water is to be substitued for steam as the heating medium, the heating coil size required is larger. This size is determined relative to that of a steam coil for similar kiln operating temperatures. 5 references.

Effect of heterogenous and homogenous air gaps on dry heat loss through the garment

Science.gov (United States)

Mert, Emel; Psikuta, Agnes; Bueno, Marie-Ange; Rossi, René M.

2015-11-01

In real life conditions, the trapped air between the human body and the garment has uneven shape and vary over the body parts as a consequence of the complex geometry of the human body. However, the existing clothing models assume uniform air layer between the human body and the garment or its full contact, which may cause large error in the output of simulations. Therefore, the aim of this study was to investigate the effect of a heterogeneous vertical air gap with different configuration of folds (size and frequency) on dry heat loss using a heated cylinder (Torso). It was found that the presence of folds in the garment led to an increased heat loss from the body in comparison to a homogeneous air gap of comparable size. Interestingly, the size of folds did not have an influence on the dry heat loss. Additionally, the effect of the contact area on dry heat loss became important when exceeding a threshold of about 42 %. The results from this study are useful for modelling of a realistic dry heat loss through the clothing and contribute to the improvement of design of protective and active sport garments.

Determination of drying kinetics and convective heat transfer coefficients of ginger slices

Science.gov (United States)

Akpinar, Ebru Kavak; Toraman, Seda

2016-10-01

In the present work, the effects of some parametric values on convective heat transfer coefficients and the thin layer drying process of ginger slices were investigated. Drying was done in the laboratory by using cyclone type convective dryer. The drying air temperature was varied as 40, 50, 60 and 70 °C and the air velocity is 0.8, 1.5 and 3 m/s. All drying experiments had only falling rate period. The drying data were fitted to the twelve mathematical models and performance of these models was investigated by comparing the determination of coefficient ( R 2), reduced Chi-square ( χ 2) and root mean square error between the observed and predicted moisture ratios. The effective moisture diffusivity and activation energy were calculated using an infinite series solution of Fick's diffusion equation. The average effective moisture diffusivity values and activation energy values varied from 2.807 × 10-10 to 6.977 × 10-10 m2/s and 19.313-22.722 kJ/mol over the drying air temperature and velocity range, respectively. Experimental data was used to evaluate the values of constants in Nusselt number expression by using linear regression analysis and consequently, convective heat transfer coefficients were determined in forced convection mode. Convective heat transfer coefficient of ginger slices showed changes in ranges 0.33-2.11 W/m2 °C.

Characteristics of Vacuum Freeze Drying with Utilization of Internal Cooling and Condenser Waste Heat for Sublimation

Directory of Open Access Journals (Sweden)

Muhammad Alhamid

2013-09-01

Full Text Available Vacuum freeze drying is an excellent drying method, but it is very energy-intensive because a relatively long drying time is required. This research investigates the utilization of condenser waste heat for sublimation as a way of accelerating the drying rate. In addition, it also investigates the effect of internal cooling combined with vacuum cooling in the pressure reduction process. Jelly fish tentacles were used as the specimen, with different configurations for condenser heat waste and internal cooling valve opening. The results show that heating with condenser heat waste can accelerate the drying rate up to 0.0035 kg/m2.s. In addition, pre-freezing by internal cooling prevents evaporation until the mass of the specimen is 0.47 g and promotes transition of the specimen into the solid phase.

Evaluation of heat stress in dry cleaner units:A case study in Qom, Iran

Directory of Open Access Journals (Sweden)

Javad Malakouti

2016-04-01

Full Text Available Background & Aims of the Study: Nowadays, heat stress is one of the most harmful physical agents in workplaces. According to the consequences of heat stress and have no information about it in Qom dry cleaner units, Iran, this study have been designed to evaluate the heat stress among workers of dry cleaner units in Qom province of Iran, in Jul-Aug 2011. Materials & Methods: This cross-sectional study was conducted in 113 units of active dry cleaner units. WBGT (Wet Bulb Globe Temperature index was selected for heat stress evaluation. In order to measure the requisite parameters, WBGT meter made of Casella Company had been used according to ISO 7243. Data had been analyzed according to Occupational Exposure Limits (OELs with SPSS V.16, using analysis of variance, independent T and LSD tests. Results: The average of WBGT index in Qom dry cleaner units of Iran were 28.98±1.64 °C. The average of WBGT index in 66.4% of units was up to 28°C. The average of relative humidity was 42.86%, the average of wet bulb temperature and globe temperature were 25.56°C and 36.72°C, respectively. The findings showed a significant correlation between the average of WBGT index and the standard recommendation level (p<0.0001. In dry cleaner units with less than 10 m2 area, heat stress was higher than other units  significantly (p<0.05. Conclusions: Heat stress in many dry cleaner units in Qom, Iran, was more than recommended OELs. Because of wet bulb and globe temperature in units were high value, the most important measures to heat controls, are technical engineering controls such as  radiation shield, insulation on boilers and modify the cooling systems.

Influence of product thickness, chamber pressure and heating conditions on production rate of freeze-dried yoghurt

Energy Technology Data Exchange (ETDEWEB)

Sharma, N.K. [G.B. Pant Univ., of Agriculture and Technology (India). Dept. of Mechanical Engineering; Arora, C.P. [Indian Inst. of Tech., New Delhi (India)

1995-06-01

The effects of product thickness, chamber pressure and heating conditions on product temperature profiles and production rate of freeze-dried yoghurt were investigated experimentally. Three sample thicknesses - 3.8 mm, 6.2 mm and 9.4 mm - were tested at chamber pressures of 0.01 and 0.5 mmHg. The production rate increased by decreasing product thickness in contact heating through the bottom of the frozen layer, whereas no significant change was observed in radiant heating. A reduction in chamber pressure from 0.50 to 0.01 mmHg increased the drying time in radiant heating. Maximum production rate was obtained when the thickness of dried product was 6.2 mm, when heat was transferred simultaneously through the frozen and dried layers, and the chamber pressure was at 0.01 mmHg. Use of the product tray developed in this study prevents the growth of dry layers at the contact surfaces. (Author)

Forest response to heat waves at the dry timberline

Science.gov (United States)

Yakir, D.; Rotenberg, E.; Tatrinov, F.; Ogee, J.; Maseyk, K.

2012-04-01

Predictions of climate change consistently indicate continuous warming and drying for the entire Mediterranean basin and other regions during the next century. Investigating forest functioning at the current dry and hot "timberline" has therefore implications for predicting future forest distribution. In such investigations we should consider the forest adjustments to extreme conditions both at the long-term average climate basis, as at the time-scale of episodic extreme events, such as heat waves and droughts. Investigating both aspects in a 45-yr old semi-arid pine forest at the dry timberline (MuSICA) was used to test our understandings of underlying processes, and our ability to account for such differential responses.

Model for heat and mass transfer in freeze-drying of pellets.

Science.gov (United States)

Trelea, Ioan Cristian; Passot, Stéphanie; Marin, Michèle; Fonseca, Fernanda

2009-07-01

Lyophilizing frozen pellets, and especially spray freeze-drying, have been receiving growing interest. To design efficient and safe freeze-drying cycles, local temperature and moisture content in the product bed have to be known, but both are difficult to measure in the industry. Mathematical modeling of heat and mass transfer helps to determine local freeze-drying conditions and predict effects of operation policy, and equipment and recipe changes on drying time and product quality. Representative pellets situated at different positions in the product slab were considered. One-dimensional transfer in the slab and radial transfer in the pellets were assumed. Coupled heat and vapor transfer equations between the temperature-controlled shelf, the product bulk, the sublimation front inside the pellets, and the chamber were established and solved numerically. The model was validated based on bulk temperature measurement performed at two different locations in the product slab and on partial vapor pressure measurement in the freeze-drying chamber. Fair agreement between measured and calculated values was found. In contrast, a previously developed model for compact product layer was found inadequate in describing freeze-drying of pellets. The developed model represents a good starting basis for studying freeze-drying of pellets. It has to be further improved and validated for a variety of product types and freeze-drying conditions (shelf temperature, total chamber pressure, pellet size, slab thickness, etc.). It could be used to develop freeze-drying cycles based on product quality criteria such as local moisture content and glass transition temperature.

A review of heat pump drying: Part 1 - systems, models and studies

Energy Technology Data Exchange (ETDEWEB)

Colak, Neslihan [Dept. of Food Engineering, Faculty of Engineering, Pamukkale Univ., 20070 Denizli (Turkey); Hepbasli, Arif [Dept. of Mechanical Engineering, Faculty of Engineering, Ege Univ., 35100 Bornova, Izmir (Turkey)

2009-09-15

The first heat pump dryer (HPD) patent applications were started in 1973, while recently, there has been a great interest in utilizing HPDs for drying fruits, vegetables and biological materials. This study deals with reviewing heat pump drying studies and consists of two parts. In the first part of this study, historical development of HPDs was briefly given first. Description of these systems was then presented. Finally, studies conducted on HPD were reviewed in terms of process efficiency modeling and progress of quality. (author)

Mass and heat transfer mechanism in wood during radio frequency/vacuum drying and numerical analysis

Institute of Scientific and Technical Information of China (English)

Xiaoran Jia; Jingyao Zhao; Yingchun Cai

2017-01-01

The mass and heat transfer mechanisms during radio frequency/vacuum (RF/V) drying of square-edged timber were analyzed and discussed in detail,and a new one-dimensional mathematical model to describe the transport phenomena of mass and heat during continuous RF/V drying was derived from conservation equations based on the mass and heat transfer theory of porous materials.The new model provided a relatively fast and efficient way to simulate vacuum drying behavior assisted by dielectric heating.Its advantages compared with the conventional models include:(1) Each independent variable has a separate control equation and is solved independently by converting the partial differential equation into a difference equation with the finite volume method;(2) The calculated data from different parts of the specimen can be displayed in the evolution curves,and the change law of the parameters can be better described.After analyzing the calculated results,most of the important phenomena observed during RF/V drying were adequately described by this model.

Drying process optimization for an API solvate using heat transfer model of an agitated filter dryer.

Science.gov (United States)

Nere, Nandkishor K; Allen, Kimberley C; Marek, James C; Bordawekar, Shailendra V

2012-10-01

Drying an early stage active pharmaceutical ingredient candidate required excessively long cycle times in a pilot plant agitated filter dryer. The key to faster drying is to ensure sufficient heat transfer and minimize mass transfer limitations. Designing the right mixing protocol is of utmost importance to achieve efficient heat transfer. To this order, a composite model was developed for the removal of bound solvent that incorporates models for heat transfer and desolvation kinetics. The proposed heat transfer model differs from previously reported models in two respects: it accounts for the effects of a gas gap between the vessel wall and solids on the overall heat transfer coefficient, and headspace pressure on the mean free path length of the inert gas and thereby on the heat transfer between the vessel wall and the first layer of solids. A computational methodology was developed incorporating the effects of mixing and headspace pressure to simulate the drying profile using a modified model framework within the Dynochem software. A dryer operational protocol was designed based on the desolvation kinetics, thermal stability studies of wet and dry cake, and the understanding gained through model simulations, resulting in a multifold reduction in drying time. Copyright © 2012 Wiley-Liss, Inc.

Dry aerosol jet printing of conductive silver lines on a heated silicon substrate

Science.gov (United States)

Efimov, A. A.; Arsenov, P. V.; Protas, N. V.; Minkov, K. N.; Urazov, M. N.; Ivanov, V. V.

2018-02-01

A new method for dry aerosol jet printing conductive lines on a heated substrate is presented. The method is based on the use of a spark discharge generator as a source of dry nanoparticles and a heating plate for their sintering. This method allows creating conductive silver lines on a heated silicon substrate up to 300 °C without an additional sintering step. It was found that for effective sintering lines of silver nanoparticles the temperature of the heated substrate should be about more than 200-250 °C. Average thickness of the sintered silver lines was equal to ∼20 µm. Printed lines showed electrical resistivity equal to 35 μΩ·cm, which is 23 times greater than the resistivity of bulk silver.

Low temperature oxidation and spontaneous combustion characteristics of upgraded low rank coal

Energy Technology Data Exchange (ETDEWEB)

Choi, H.K.; Kim, S.D.; Yoo, J.H.; Chun, D.H.; Rhim, Y.J.; Lee, S.H. [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

2013-07-01

The low temperature oxidation and spontaneous combustion characteristics of dried coal produced from low rank coal using the upgraded brown coal (UBC) process were investigated. To this end, proximate properties, crossing-point temperature (CPT), and isothermal oxidation characteristics of the coal were analyzed. The isothermal oxidation characteristics were estimated by considering the formation rates of CO and CO{sub 2} at low temperatures. The upgraded low rank coal had higher heating values than the raw coal. It also had less susceptibility to low temperature oxidation and spontaneous combustion. This seemed to result from the coating of the asphalt on the surface of the coal, which suppressed the active functional groups from reacting with oxygen in the air. The increasing upgrading pressure negatively affected the low temperature oxidation and spontaneous combustion.

Use of geothermal heat for crop drying and related agricultural applications. Final report

Energy Technology Data Exchange (ETDEWEB)

Gordon, T.J.; Wright, T.C.; Fein, E.; Munson, T.R.; Richmond, R.C.

1978-03-01

Observations led to the selection of the alfalfa dehydration industry for in-depth analysis of the application of moderate-temperature geothermal heat. Six geothermal heat exchanger/dryer configurations were examined. A low-temperature conveyor dryer using geothermal water to supply all required heat was chosen for site-specific analysis, the retrofitting of a large alfalfa dehydration plant within the Heber KGRA in the Imperial Valley, California. Even in the most favorable scenario--sharing a geothermal pipeline with the neighboring fertilizer plant--geothermal retrofitting would increase the price of the alfalfa ''dehy'' about 40 percent. The geothermal brine is estimated to cost $2.58/million Btu's compared with a 1977 natural gas cost of $1.15. Capital cost for heat exchangers and the new dryers is estimated at $3.3 million. The Heber plant appeared to offer the only good opportunity for geothermal retrofitting of an existing alfalfa dehydration plant. Construction of new plants at geothermal resource sites cannot be justified due to the uncertain state of the ''dehy'' industry. Use of geothermal heat for drying other crops may be much more promising. The potato dehydration industry, which is concentrated in the geothermal-rich Snake River Valley of Idaho, appears to offer good potential for geothermal retrofitting; about 4.7 x 10{sup 12}Btu's are used annually by plants within 50 miles of resources. Drying together at the geothermal wellhead several crops that have interlocking processing seasons and drying-temperature requirements may be quite attractive. The best ''multicrop drying center'' site identified was at Power Ranch Wells, Arizona; 34 other sites were defined. Agricultural processing applications other than drying were investigated briefly.

Heat and mass transfer coefficients and modeling of infrared drying of banana slices

Directory of Open Access Journals (Sweden)

Fernanda Machado Baptestini

Full Text Available ABSTRACT Banana is one of the most consumed fruits in the world, having a large part of its production performed in tropical countries. This product possesses a wide range of vitamins and minerals, being an important component of the alimentation worldwide. However, the shelf life of bananas is short, thus requiring procedures to prevent the quality loss and increase the shelf life. One of these procedures widely used is drying. This work aimed to study the infrared drying process of banana slices (cv. Prata and determine the heat and mass transfer coefficients of this process. In addition, effective diffusion coefficient and relationship between ripening stages of banana and drying were obtained. Banana slices at four different ripening stages were dried using a dryer with infrared heating source with four different temperatures (65, 75, 85, and 95 ºC. Midilli model was the one that best represented infrared drying of banana slices. Heat and mass transfer coefficients varied, respectively, between 46.84 and 70.54 W m-2 K-1 and 0.040 to 0.0632 m s-1 for temperature range, at the different ripening stages. Effective diffusion coefficient ranged from 1.96 to 3.59 × 10-15 m² s-1. Activation energy encountered were 16.392, 29.531, 23.194, and 25.206 kJ mol-1 for 2nd, 3rd, 5th, and 7th ripening stages, respectively. Ripening stages did not affect the infrared drying of bananas.

Effect of drying method on the adsorption isotherms and isosteric heat of passion fruit pulp powder

Directory of Open Access Journals (Sweden)

Maria Angélica Marques Pedro

2010-12-01

Full Text Available The sorption behavior of dry products is generally affected by the drying method. The sorption isotherms are useful to determine and compare thermodynamic properties of passion fruit pulp powder processed by different drying methods. The objective of this study is to analyze the effects of different drying methods on the sorption properties of passion fruit pulp powder. Passion fruit pulp powder was dehydrated using different dryers: vacuum, spray dryer, vibro-fluidized, and freeze dryer. The moisture equilibrium data of Passion Fruit Pulp (PFP powders with 55% of maltodextrin (MD were determined at 20, 30, 40 and 50 ºC. The behavior of the curves was type III, according to Brunauer's classification, and the GAB model was fitted to the experimental equilibrium data. The equilibrium moisture contents of the samples were little affected by temperature variation. The spray dryer provides a dry product with higher adsorption capacity than that of the other methods. The vibro-fluidized bed drying showed higher adsorption capacity than that of vacuum and freeze drying. The vacuum and freeze drying presented the same adsorption capacity. The isosteric heats of sorption were found to decrease with increasing moisture content. Considering the effect of drying methods, the highest isosteric heat of sorption was observed for powders produced by spray drying, whereas powders obtained by vacuum and freeze drying showed the lowest isosteric heats of sorption.

Simultaneous rough rice drying and rice bran stabilization using infrared radiation heating

Science.gov (United States)

The objective of this study was to develop a new rice drying method by using IR heating followed by tempering. Freshly harvested medium grain rice (M206) samples with different initial moisture contents (IMCs) were used in this study. The samples were dried for one- and two-passes by using a catalyt...

Self-heating of dried industrial wastewater sludge: lab-scale investigation of supporting conditions.

Science.gov (United States)

Della Zassa, M; Biasin, A; Zerlottin, M; Refosco, D; Canu, P

2013-06-01

We studied the reactivity of dried sludge produced by treatment of wastewater, mainly from tanneries. The solids transformations have been first characterized with thermal analysis (TGA and DSC) proving that exothermic transformation takes place at fairly low temperature, before the total organic combustion that occurs in air above 400°C. The onset of low temperature reactions depends on the heating rate and it can be below 100°C at very small heating rate. Then, we reproducibly determined the conditions to trigger dried sludge self-heating at the laboratory scale, on samples in the 0.2-0.3 kg size. Thermal insulation, some aeration and addition of water are key factors. Mastering the self-heating at this scale allows more detailed investigations as well as manipulation of conditions, to understand its nature, course and remediation. Here we report proves and discussions on the role of air, water, particle size, porosity and biological activity, as well as proving that also dried sludge from similar sources lead to self-heating. Tests demonstrate that air and water are simultaneously required for significant self-heating to occur. They act in diverging directions, both triggering the onset of the reactions and damping the temperature rise, by supporting heat loss. The higher the O2 concentration, the higher the solids heating rate. More added water prolongs the exothermic phase. Further additions of water can reactivate the material. Water emphasizes the exothermic processes, but it is not sufficient to start it in an air-free atmosphere. The initial solid moisture concentration (between 8% and 15%) affects the onset of self-heating as intuitive. The sludge particles size strongly determines the strength and extent of the heat release, indicating that surface reactions are taking place. In pelletized particles, limitations to water and air permeability mitigates the reaction course. Copyright © 2013 Elsevier Ltd. All rights reserved.

Heat transfer modelling in a spent-fuel dry storage system

International Nuclear Information System (INIS)

Ritz, J.B.; Le Bonhomme, S.

2001-01-01

The purpose of this paper is to present a numerical modelling of heat transfers in a Spent-Fuel horizontal dry storage. The horizontal dry storage is an interesting issue to momentary store spent fuel containers before the final storage. From a thermal point of view, the cooling of spent fuel container by natural convection is a suitable and inexpensive process but it necessitates to well define the dimensions of the concept due to the difficulty to control the thermal environment. (author)

Experimental determination of the key heat transfer mechanisms in pharmaceutical freeze-drying.

Science.gov (United States)

Ganguly, Arnab; Nail, Steven L; Alexeenko, Alina

2013-05-01

The study is aimed at quantifying the relative contribution of key heat transfer modes in lyophilization. Measurements of vial heat transfer rates in a laboratory-scale freeze-dryer were performed using pure water, which was partially sublimed under various conditions. The separation distance between the shelf and the vial was systematically varied, and sublimation rates were determined gravimetrically. The heat transfer rates were observed to be independent of separation distance between the vial and the shelf and linearly dependent on pressure in the free molecular flow limit, realized at low pressures (120 mTorr), heat transfer rates were independent of pressure and inversely proportional to separation distance. Previous heat transfer studies in conventional freeze-drying cycles have attributed a dominant portion of the total heat transfer to radiation, the rest to conduction, whereas convection has been found to be insignificant. Although the measurements reported here confirm the significance of the radiative and gas conduction components, the convective component has been found to be comparable to the gas conduction contribution at pressures greater than 100 mTorr. The current investigation supports the conclusion that the convective component of the heat transfer cannot be ignored in typical laboratory-scale freeze-drying conditions. Copyright © 2013 Wiley Periodicals, Inc.

Pysical Properties of Soil with Addition of Sewage Dried with Heated Edible Oil

OpenAIRE

大坪, 政美; 中司, 敬; 中園, 修三; 中園, 英司; 徳留, 斉将

2000-01-01

The present study investigates the water holding capacity, density, permeability, and swelling properties of the soil samples mixed with the sewage that was dried with heated edible oil. For comparison similar experiments were conducted for the soil samples mixed with sun-dried sewage and sewage compost. The water holding capacity was higher for the soil samples with oil-dried and sun-dried sewage addition than for those with sewage-compost addition. For statically compacted soil samples, wit...

Development of Hybrid Kiln Drying System with Radio Frequency Heating for the Sugi Heart Timber

OpenAIRE

Piao, Jinji; Fujimoto, Noboru; Yamamoto, Yasushi; Nagata, Soji

2007-01-01

In this study, proper applied stage of the radio-frequency (RF) heating during kiln drying based on the quality concerning the surface checks of the boxed heart timbers was examined. At the stage of the RF heating the moisture contents decreased clearly at the internal parts of timbers. The surface stress of the sugi (Cryptomeria japonica D. Don) boxed heart timber changed into the compression stress by the RF heating in any drying stage. The surface checks increased according to the decrease...

Effect of Physical Osmosis Methods on Quality of Tilapia Fillets Processed by Heat Pump Drying

Directory of Open Access Journals (Sweden)

Li Min

2017-06-01

Full Text Available In order to achieve the influence of different pretreatment methods on heat pump dried tilapia fillets, the effects of trehalose, ultrasound-assisted and freeze-thaw cycle assisted osmotic dehydration on the color, rehydration, texture and Ca2+-ATPase activity were investigated. Tilapia fillets (100 mm length × 50 mm width × 5 mm height were first osmoconcentrated in a trehalose solution combined with 4°C under atmospheric pressure for 1 h, different power of ultrasound and freeze-thawing respectively, then heat pump dried. The results showed that under the same drying method, the comprehensive score of ultrasound in 400 Watt was best, compared to freeze-thaw, the ultrasound pretreatment had a significant (p0.05 effect on the rehydration and texture. However, both of them significantly (p<0.05 affected the quality in comparison to that of osmosis at 4°C. It indicates that suitable ultrasonic pretreatment conditions improve the quality of dried products effectively and the conclusion of this research provides reference for heat pump dried similar products.

Thermoregulatory responses to acute heat loads in rats following spontaneous running.

Science.gov (United States)

Sugimoto, N; Shido, O; Sakurada, S; Nagasaka, T

1999-02-01

Earlier studies showed that spontaneous exercise training in rodents shifted their core temperature and thermoeffector thresholds to high levels. The present study investigated heat loss and heat production responses to acute heat loads of exercise-trained rats. The exercise-trained rats were allowed to run in a running wheel freely for 6 months, while the sedentary controls were denied access to the wheel during the same period. Then, they were loosely restrained and put in a direct calorimeter. After thermal equilibrium had been attained, they were warmed for 30 min with an intraperitoneal electric heater (internal heating). At least 2 h later, the rats were externally warmed for 90 min by raising the ambient temperature from 24 to 38C (external warming). Hypothalamic temperature (Thy), evaporative and nonevaporative heat loss (R+C+K) and heat production were measured. Internal and external heating significantly increased Thy. During internal heating, the magnitude of the increase in Thy was significantly smaller and the amount of increase in (R+C+K) was significantly greater in the exercise-trained rats than in the controls. The slope showing the relationship between Thy and (R+C+K) in the trained rats was significantly steeper than that in the controls. During external warming, the magnitude of increase in Thy of the exercise-trained rats was significantly greater than that of the controls. The slope showing the relationship between Thy and (R+C+K) in the trained rats was not different from that in the controls. Changes in evaporative heat loss and heat production during the two types of heat load did not differ between the two groups. The results suggest that, in rats, exercise training with voluntary running improves heat tolerance through enhancing nonevaporative heat loss response. However, this may be the case only when the rats are subjected to a direct internal heat load.

Development of heat pump and infrared-convective dryer and performance analysis for stale bread drying

International Nuclear Information System (INIS)

Aktaş, Mustafa; Şevik, Seyfi; Aktekeli, Burak

2016-01-01

Highlights: • Investigation of stale bread drying behaviors by developing the HPD and IRD. • New techniques for the HP and IR dryers are proposed and found to be efficient. • Evaluations on potential uses low temperature applications of the dryers were reported. • 35.6% of energy saving was provided by heat recovery device. • The overall system efficiency of HPD was calculated as 13–60%. - Abstract: This experimental study aims to develop a heat pump dryer (HPD) and an infrared dryer (IRD) also the comparative empirical analyses of these two methods and to analyze the drying kinetic of stale bread sliced 15 mm thickness and effectiveness on the drying kinetics of the stale bread of dryers. Dryers have been developed by using different techniques such as heat recovery unit, proportional control (PC) of drying air temperature, simultaneous control of the relative humidity–temperature–air flow rate, water cycle dehumidifier and closed-loop cycle to increase the drying efficiency of industrial drying applications. The highest coefficient of performance of the whole heat pump system (COP_w_s_,_H_P) was calculated as 3.7 and drying efficiencies of the IRD and HPD systems were calculated as 39% and 25%, respectively. When the HPD and IRD systems were compared in terms of drying time and energy consumption, it was observed that the IRD system did not only shortened the drying time up to 69%, but also decreased the energy consumption of the system by 43.2%. Based on the obtained results the effective moisture diffusivity (D_e) was calculated in the range from 8.3 × 10"−"8 to 3.2 × 10"−"7 m"2/s and mass transfer coefficient (h_m) was varied from 1.17 × 10"−"5 to 4.52 × 10"−"5 m/s. It was concluded that both dryers have significant effect in reduction of water content; the relative humidity controlled HPD can be applied efficiently for dryers and the dried stale bread can be reused as bread crumb by food industry.

Probing Conformational Change of Bovine Serum Albumin–Dextran Conjugates under Controlled Dry Heating

Energy Technology Data Exchange (ETDEWEB)

Xia, Shuqin; Li, Yunqi; Zhao, Qin; Li, Ji; Xia, Qiuyang; Zhang, Xiaoming; Huang, Qingrong (Rutgers); (Chinese Aca. Sci.); (Jiangnan)

2015-04-29

The time-dependent conformational change of bovine serum album (BSA) during Maillard reaction with dextran under controlled dry heating has been studied by small-angle X-ray scattering, fluorescence spectroscopy, dynamic light scattering, and circular dichroism analysis. Through the research on the radii of gyration (R_g), intrinsic fluorescence, and secondary structure, conjugates with dextran coating were found to inhibit BSA aggregation and preserve the secondary structure of native BSA against long-time heat treatment during Maillard reaction. The results suggested that the hydrophilic dextran was conjugated to the compact protein surface and enclosed it and more dextran chains were attached to BSA with the increase of the heating time. The study presented here will be beneficial to the understanding of the conformational evolution of BSA molecules during the dry-heating Maillard reaction and to the control of the protein–polysaccharide conjugate structure.

Potential weather modification caused by waste heat release from large dry cooling towers

International Nuclear Information System (INIS)

Lee, J.

1979-01-01

A numerical model of a cooling tower plume is employed to study the possible atmospheric effects of thermal plumes from natural draft dry cooling towers. Calculations are performed for both single and multiple towers, each of which can dissipate the waste heat from a nominal 1000 MWe power generating unit, and the results are compared with those for wet cooling towers associated with plants of the same generating capacity. Dry cooling tower plumes are found to have a higher potential for inducing convective clouds than wet cooling tower plumes, under most summertime meteorological conditions. This is due to the fact that both the sensible heat and momentum fluxes from a dry tower in summer are approximately one order of magnitude larger than those from a wet cooling tower

Effects of physical parameters on the heat and mass transfer characteristics in freeze-drying processes of fruits and vegetables

Energy Technology Data Exchange (ETDEWEB)

Guo, Yuming; Liu, Lijuan; Liang, Li [Shanxi Agricultural Univ. (China). Coll. of Engineering and Technology], E-mail: guoyuming99@sina.com

2008-07-01

Studying the effects mechanism of material physical parameters on the heat and mass transfer characteristics, the process parameters and energy consumption during freeze-drying process is of importance in improving the vacuum freeze-drying process with low energy consumption. In this paper, the sliced and mashed carrots of one variety were selected to perform the vacuum freeze-drying experiments. First, the variation laws of surface temperatures and sublimation front temperatures of the two shapes samples during the freeze-drying processes were analyzed, and it was verified that the process of sliced carrots is controlled by mass transfer, while that of the mashed ones is heat-transfer control. Second, the variations of water loss rate, energy consumption and temperature of the two shapes samples under the appropriate heating plate temperature and the different drying chamber pressure were analyzed. In addition, the effects of thermal conductivity and thermal diffusivity on freeze-drying time and process parameters were discussed by utilizing the theory of heat and mass transfer. In conclusion, under the heat transfer condition, the temperature of the heating plate should be as high as possible within the permitted range, and the drying chamber pressure should be set at optimal level. While under the mass transport-limited condition, the pressure level need to be altered in short time. (author)

THERMAL POWER LOSS COMPENSATION IN THE PRODUCTION OF COOKED AND DRIED GRAINS WITH HEAT PUMPS USING

Directory of Open Access Journals (Sweden)

S. A. Shevtsov

2015-01-01

Full Text Available Using scientificand practical experience and analysis of recent innovative activity on modernization of food concentrates production, a new variant of the energy-efficient processing of cereal crops using superheated steam and direct involvement in the cooking and drying process waste energy using the vapor compression heat pump was suggested. A method for production of cereal concentrates, which is realized using microprocessor control of technological parameters. According to the information on the processes of cereals washing, cooking, drying and cooling microprocessor provides regime parameters control under the restrictions due to both yield of cooked and dried cereal of high quality and economic feasibility. At the same time the amount of moisture is continuously determined in the recirculation loop formed by the evaporation from the cereals in the drying process. To implement the proposed method of cooked and dried cereals production it is offered to use refrigerationand compressor unit operating in a heat pump mode. The refrigerant to be used is khladon 12V1 CF2ClBr with a boiling point in the evaporator of 4°C and the condensing temperature of 153.7 °C. The use of the heat pump in the heat supply system of cooked and dried cereals production instead of electric heaters will reduce power costs by 1.72 times. The proposed method for the production and control of technological parameters in the field of the product acceptable technological properties will provide high quality cooked and dried cereals; an increase in thermal efficiency by making full use of the waste heat of superheated steam; the reduction of specific energy consumption by 25-30 %; the creation of waste-free and environmentally friendly technologies for cereal production.

Effect of Tube Diameter on The Design of Heat Exchanger in Solar Drying system

Science.gov (United States)

Husham Abdulmalek, Shaymaa; Khalaji Assadi, Morteza; Al-Kayiem, Hussain H.; Gitan, Ali Ahmed

2018-03-01

The drying of agriculture product consumes a huge fossil fuel rates that demand to find an alternative source of sustainable environmental friendly energy such as solar energy. This work presents the difference between using solar heat source and electrical heater in terms of design aspect. A circular-finned tube bank heat exchanger is considered against an electrical heater used as a heat generator to regenerate silica gel in solar assisted desiccant drying system. The impact of tube diameter on the heat transfer area was investigated for both the heat exchanger and the electrical heater. The fin performance was investigated by determining fin effectiveness and fin efficiency. A mathematical model was developed using MATLAB to describe the forced convection heat transfer between hot water supplied by evacuated solar collector with 70 °C and ambient air flow over heat exchanger finned tubes. The results revealed that the increasing of tube diameter augments the heat transfer area of both heat exchanger and electrical heater. The highest of fin efficiency was around 0.745 and the lowest was around 0.687 while the fin effectiveness was found to be around 0.998.

Experimental determination of surface heat transfer coefficient in a dry ice-ethanol cooling bath using a numerical approach.

Science.gov (United States)

Santos, M V; Sansinena, M; Zaritzky, N; Chirife, J

BACKGROUND: Dry ice-ethanol bath (-78 degree C) have been widely used in low temperature biological research to attain rapid cooling of samples below freezing temperature. The prediction of cooling rates of biological samples immersed in dry ice-ethanol bath is of practical interest in cryopreservation. The cooling rate can be obtained using mathematical models representing the heat conduction equation in transient state. Additionally, at the solid cryogenic-fluid interface, the knowledge of the surface heat transfer coefficient (h) is necessary for the convective boundary condition in order to correctly establish the mathematical problem. The study was to apply numerical modeling to obtain the surface heat transfer coefficient of a dry ice-ethanol bath. A numerical finite element solution of heat conduction equation was used to obtain surface heat transfer coefficients from measured temperatures at the center of polytetrafluoroethylene and polymethylmetacrylate cylinders immersed in a dry ice-ethanol cooling bath. The numerical model considered the temperature dependence of thermophysical properties of plastic materials used. A negative linear relationship is observed between cylinder diameter and heat transfer coefficient in the liquid bath, the calculated h values were 308, 135 and 62.5 W/(m 2 K) for PMMA 1.3, PTFE 2.59 and 3.14 cm in diameter, respectively. The calculated heat transfer coefficients were consistent among several replicates; h in dry ice-ethanol showed an inverse relationship with cylinder diameter.

Design and simulation of heat exchangers using Aspen HYSYS, and Aspen exchanger design and rating for paddy drying application

Science.gov (United States)

Janaun, J.; Kamin, N. H.; Wong, K. H.; Tham, H. J.; Kong, V. V.; Farajpourlar, M.

2016-06-01

Air heating unit is one of the most important parts in paddy drying to ensure the efficiency of a drying process. In addition, an optimized air heating unit does not only promise a good paddy quality, but also save more for the operating cost. This study determined the suitable and best specifications heating unit to heat air for paddy drying in the LAMB dryer. In this study, Aspen HYSYS v7.3 was used to obtain the minimum flow rate of hot water needed. The resulting data obtained from Aspen HYSYS v7.3 were used in Aspen Exchanger Design and Rating (EDR) to generate heat exchanger design and costs. The designs include shell and tubes and plate heat exchanger. The heat exchanger was designed in order to produce various drying temperatures of 40, 50, 60 and 70°C of air with different flow rate, 300, 2500 and 5000 LPM. The optimum condition for the heat exchanger were found to be plate heat exchanger with 0.6 mm plate thickness, 198.75 mm plate width, 554.8 mm plate length and 11 numbers of plates operating at 5000 LPM air flow rate.

Dry Heat Treatment Reduces the Occurrence of Cladosporium cucumerinum, Ascochyta citrullina, and Colletotrichum orbiculare on the Surface and Interior of Cucumber Seeds

Directory of Open Access Journals (Sweden)

Yanxia Shi

2016-01-01

Full Text Available Dry heat treatment has been identified as a method for disinfecting seed-borne pathogens in vegetable seeds. This study demonstrated that three seed-borne pathogens of cucumber (Cladosporium cucumerinum that causes scabs, Ascochyta citrullina that results in gummy stem blight, and Colletotrichum orbiculare that induces anthracnose could be effectively eradicated from cucumber seeds by dry heat treatment. In vitro growth of these three pathogens was inhibited by dry heat treatment at 70 °C for 40 min. These pathogens were inactivated after exposing infected seeds to 70 °C dry heat for at least 90 min. Seed infection was significantly reduced by exposing the seeds to 70 °C dry heat for at least 40 min. Seed moisture content and germination were slightly reduced after 70 °C heat treatment for 40–120 min. Seed vigor remained at a high level after dry heat treatment at 70 °C for 90 min. In conclusion, 70 °C dry heat treatment for 90 min was determined to be the optimal method for eradication of C. cucumerinum, Didymella bryoniae, and C. orbiculare from cucumber seeds.

Drying and heat decomposition of biomass during the production of biochar

Science.gov (United States)

Lyubov, V. K.; Popova, E. I.

2017-11-01

The process of wood torrefaction provides an opportunity to combine properties of biofuel and steam coal. Different degrees of biofuel heat treating leads to varied outcomes and varied biochar heating value. Therefore, the torrefaction process requires optimal operation that ensures the highest heating value of biochar with the lowest energy loss. In this paper we present the experimental results of drying cycle and thermal decomposition of particles of spruce stem wood and hydrolytic lignin in argon under various temperature conditions and basic material humidity as well as changes in the morphological structure of the biomass and its grain size composition during the torrefaction.

The Effect of Body Weight on Heat Strain Indices in Hot and Dry Climatic Conditions

Directory of Open Access Journals (Sweden)

Habibi

2016-03-01

Full Text Available Background Being overweight is a characteristic that may influence a person’s heat exchange. Objectives The purpose of this study was to assess the effect of body weight on heat strain indices in hot and dry climatic conditions. Materials and Methods This study was completed with a sample of 30 participants with normal weights, as well as 25 participants who were overweight. The participants were physically inactive for a period of 120 minutes in a climatic chamber with hot and dry conditions (22 - 32°C and with 40% relative humidity (RH.The physiological strain index (PSI and heat strain score index (HSSI questionnaires were used. Simultaneous measurements were completed during heat exposure for periods of five minutes. The resting periods acted as the initial measurements for 15 minutes. Results In both groups, oral temperature, heart rate, and thermal perceptual responses increased during heat exposure. The means and standard deviations of heart rate and oral temperature were gathered when participants were in hot and dry climatic conditions and were not physically active. The heart rates and oral temperatures were 79.21 ± 5.93 bpm and 36.70 ± 0.45°C, respectively, for those with normal weights. For overweight individuals, the measurements for heart rate and oral temperature reached 82.21 ± 8.9 bpm and 37.84 ± 0.37°C, respectively. Conclusions The results showed that, compared to participants with normal weights, physiological and thermal perceptual responses were higher in overweight participants. Therefore, overweight individuals should avoid hot/dry weather conditions to decrease the amount of heat strain.

Biomass gasification for CHP with dry gas cleaning and regenerative heat recovery

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-05-01

Small scale CHP plants based on biomass gasification technologies are generally expensive and not very efficient due to gas quality problems which increase operation and maintenance cost as well as breakdown. To overcome this situation the team has developed, integrated and tested a complete biomass gasification combine heat and power prototype plant of 250 kWth equipped with a specifically developed dry gas cleaning and heat recovery system. The dry gas cleaning device is a simple dry gas regenerative heat exchanger where tars are stopped by condensation but working at a temperature above due point in order to avoid water condensation. Two types of heat particles separation devices have been tested in parallel multi-cyclone and ceramic filters. After several month spent on modelling design, construction and optimisation, a full test campaign of 400 hours continuous monitoring has been done where all working parameters has been monitored and gas cleaning device performances has been assessed. Results have shown: Inappropriateness of the ceramic filters for the small scale unit due to operation cost and too high sensibility of the filters to the operation conditions fluctuating in a wide range, despite a very high particle separation efficiency 99 %; Rather good efficiency of the multi-cyclone 72% but not sufficient for engine safety. Additional conventional filters where necessary for the finest part; Inappropriateness of the dry gas heat exchanger device for tar removal partly due to a low tar content of the syngas generated, below 100 mg/Nm{sup 3} , but also due to their composition which would have imposed, to be really efficient, a theoretical condensing temperature of 89 C below the water condensation temperature. These results have been confirmed by laboratory tests and modelling. However the tar cracking phase have shown very interesting results and proved the feasibility of thermal cracking with full cleaning of the heat exchanger without further mechanical

Dielectric properties of dried vegetable powders and their temperature profile during radio frequency heating

Science.gov (United States)

Recently, Salmonella contamination was identified in low-moisture foods including dried vegetable powder. Radio Frequency (RF) dielectric heating is a potential alternative pasteurization method with short heating time. Dielectric properties of broccoli powder with 6.9, 9.1, 12.2, and 14.9%, w. b....

Associations between risk perception, spontaneous adaptation behavior to heat waves and heatstroke in Guangdong province, China.

Science.gov (United States)

Liu, Tao; Xu, Yan Jun; Zhang, Yong Hui; Yan, Qing Hua; Song, Xiu Ling; Xie, Hui Yan; Luo, Yuan; Rutherford, Shannon; Chu, Cordia; Lin, Hua Liang; Ma, Wen Jun

2013-10-02

In many parts of the world, including in China, extreme heat events or heat waves are likely to increase in intensity, frequency, and duration in light of climate change in the next decades. Risk perception and adaptation behaviors are two important components in reducing the health impacts of heat waves, but little is known about their relationships in China. This study aimed to examine the associations between risk perception to heat waves, adaptation behaviors, and heatstroke among the public in Guangdong province, China. A total of 2,183 adult participants were selected using a four-stage sampling method in Guangdong province. From September to November of 2010 each subject was interviewed at home by a well-trained investigator using a structured questionnaire. The information collected included socio-demographic characteristics, risk perception and spontaneous adaptation behaviors during heat wave periods, and heatstroke experience in the last year. Chi-square tests and unconditional logistic regression models were employed to analyze the data. This study found that 14.8%, 65.3% and 19.9% of participants perceived heat waves as a low, moderate or high health risk, respectively. About 99.1% participants employed at least one spontaneous adaptation behavior, and 26.2%, 51.2% and 22.6% respondents employed 7 adaptation behaviors during heat waves, respectively. Individuals with moderate (OR=2.93, 95% CI: 1.38-6.22) or high (OR=10.58, 95% CI: 4.74-23.63) risk perception experienced more heatstroke in the past year than others. Drinking more water and wearing light clothes in urban areas, while decreasing activity as well as wearing light clothes in rural areas were negatively associated with heatstroke. Individuals with high risk perception and employing risks of heatstroke (OR=47.46, 95% CI: 12.82-175.73). There is a large room for improving health risk perception and adaptation capacity to heat waves among the public of Guangdong province. People with higher

Associations between risk perception, spontaneous adaptation behavior to heat waves and heatstroke in Guangdong province, China

Science.gov (United States)

2013-01-01

Background In many parts of the world, including in China, extreme heat events or heat waves are likely to increase in intensity, frequency, and duration in light of climate change in the next decades. Risk perception and adaptation behaviors are two important components in reducing the health impacts of heat waves, but little is known about their relationships in China. This study aimed to examine the associations between risk perception to heat waves, adaptation behaviors, and heatstroke among the public in Guangdong province, China. Methods A total of 2,183 adult participants were selected using a four-stage sampling method in Guangdong province. From September to November of 2010 each subject was interviewed at home by a well-trained investigator using a structured questionnaire. The information collected included socio-demographic characteristics, risk perception and spontaneous adaptation behaviors during heat wave periods, and heatstroke experience in the last year. Chi-square tests and unconditional logistic regression models were employed to analyze the data. Results This study found that 14.8%, 65.3% and 19.9% of participants perceived heat waves as a low, moderate or high health risk, respectively. About 99.1% participants employed at least one spontaneous adaptation behavior, and 26.2%, 51.2% and 22.6% respondents employed 7 adaptation behaviors during heat waves, respectively. Individuals with moderate (OR=2.93, 95% CI: 1.38-6.22) or high (OR=10.58, 95% CI: 4.74-23.63) risk perception experienced more heatstroke in the past year than others. Drinking more water and wearing light clothes in urban areas, while decreasing activity as well as wearing light clothes in rural areas were negatively associated with heatstroke. Individuals with high risk perception and employing risks of heatstroke (OR=47.46, 95% CI: 12.82-175.73). Conclusions There is a large room for improving health risk perception and adaptation capacity to heat waves among the public of

Effect of nutritional immunomodulation and heat stress during the dry period on subsequent performance of cows.

Science.gov (United States)

Fabris, Thiago F; Laporta, Jimena; Corra, Fabiana N; Torres, Yazielis M; Kirk, David J; McLean, Derek J; Chapman, J D; Dahl, Geoffrey E

2017-08-01

Heat stress in dairy cows during the dry period impairs milk yield in the next lactation. Feeding OmniGen-AF (OG; Phibro Animal Health Corp., Teaneck, NJ) to lactating cows during heat stress may increase dry matter intake (DMI) and lowers respiration rate (RR) and rectal temperature (RT), but the effects in dry cows are not known. We hypothesized that OG supplementation before, during, and after the dry period (approximately 160 d total) would overcome the effects of heat stress and improve cow performance in the next lactation. Cows were randomly assigned to OG or control (placebo) treatments for the last 60 d in milk (DIM), based on mature-equivalent milk yield in the previous lactation. Cows were dried off 45 d before expected calving and randomly assigned to heat stress (HT) or cooling (CL) treatments. Thus, cows received dietary supplementation during late lactation before they were exposed to either CL or HT. After dry-off, treatment groups included heat stress with placebo (HT, only shade, 56 g/d of placebo, n = 17), HT with OG supplementation (HTOG, 56 g/d of OG, n = 19), cooling with placebo (CL, shade, fans, and soakers, 56 g/d of placebo, n = 16), and CL with OG supplementation (CLOG, 56 g/d of OG, n = 11). After parturition, all cows were kept under the same CL system and management, and all cows continued to receive OG or control treatment until 60 DIM. Cooling cows during the dry period reduced afternoon RT (CL vs. HT; 38.9 ± 0.05 vs. 39.3 ± 0.05°C) and RR (CL vs. HT; 45 ± 1.6 vs. 77 ± 1.6 breaths/min). Respiration rate was also decreased by OG supplementation under HT conditions (HTOG vs. HT; 69.7 ± 1.6 vs. 77.2 ± 1.6 breaths/min). An interaction was observed between OG supplementation and HT; HTOG cows tended to have lower morning RT compared with HT cows. During the dry period, OG reduced DMI relative to control cows. Birth weight was greater in calves from CL cows (CL vs. HT; 40.6 ± 1.09 vs. 38.7 ± 1.09 kg). No differences were detected

CFD Simulation of Heat and Fluid Flow for Spent Fuel in a Dry Storage

International Nuclear Information System (INIS)

In, Wangkee; Kwack, Youngkyun; Kook, Donghak; Koo, Yanghyun

2014-01-01

A dry storage system is used for the interim storage of spent fuel prior to permanent depository and/or recycling. The spent fuel is initially stored in a water pool for more than 5 years at least after dispatch from the reactor core and is transported to dry storage. The dry cask contains a multiple number of spent fuel assemblies, which are cooled down in the spent fuel pool. The dry cask is usually filled up with helium gas for increasing the heat transfer to the environment outside the cask. The dry storage system has been used for more than a decade in United States of America (USA) and the European Union (EU). Korea is also developing a dry storage system since its spent fuel pool is anticipated to be full within 10 years. The spent fuel will be stored in a dry cask for more than 40 years. The integrity and safety of spent fuel are important for long-term dry storage. The long-term storage will experience the degradation of spent fuel such as the embrittlement of fuel cladding, thermal creep and hydride reorientation. High burn-up fuel may expedite the material degradation. It is known that the cladding temperature has a strong influence on the material degradation. Hence, it is necessary to accurately predict the local distribution of the cladding temperature using the Computational Fluid Dynamics (CFD) approach. The objective of this study is to apply the CFD method for predicting the three-dimensional distribution of fuel temperature in a dry cask. This CFD study simulated the dry cask for containing the 21 fuel assemblies under development in Korea. This paper presents the fluid velocity and temperature distribution as well as the fuel temperature. A two-step CFD approach was applied to simulate the heat and fluid flow in a dry storage of 21 spent fuel assemblies. The first CFD analysis predicted the helium flow and temperature in a dry cask by a assuming porous body of the spent fuel. The second CFD analysis was to simulate a spent fuel assembly in the

Comparison of drying characteristic and uniformity of banana cubes dried by pulse-spouted microwave vacuum drying, freeze drying and microwave freeze drying.

Science.gov (United States)

Jiang, Hao; Zhang, Min; Mujumdar, Arun S; Lim, Rui-Xin

2014-07-01

To overcome the flaws of high energy consumption of freeze drying (FD) and the non-uniform drying of microwave freeze drying (MFD), pulse-spouted microwave vacuum drying (PSMVD) was developed. The results showed that the drying time can be dramatically shortened if microwave was used as the heating source. In this experiment, both MFD and PSMVD could shorten drying time by 50% as compared to the FD process. Depending on the heating method, MFD and PSMVD dried banana cubes showed trends of expansion while FD dried samples demonstrated trends of shrinkage. Shrinkage also brought intensive structure and highest fracturability of all three samples dried by different methods. The residual ascorbic acid content of PSMVD dried samples can be as high as in FD dried samples, which were superior to MFD dried samples. The tests confirmed that PSMVD could bring about better drying uniformity than MFD. Besides, compared with traditional MFD, PSMVD can provide better extrinsic feature, and can bring about improved nutritional features because of the higher residual ascorbic acid content. © 2013 Society of Chemical Industry.

Modelling the mid-infrared drying of sweet potato: kinetics, mass and heat transfer parameters, and energy consumption

Science.gov (United States)

Onwude, Daniel I.; Hashim, Norhashila; Abdan, Khalina; Janius, Rimfiel; Chen, Guangnan

2018-04-01

This study investigated the drying kinetics, mass and heat transfer characteristics of sweet potato slices (0.4-0.6 cm thickness) during drying based on mid-infrared experimental set-up (intensity of 1100-1400 W/m2). Thin layer drying models were used to evaluate the drying kinetics of sweet potato slices. Two analytical models (Fick's diffusion model, and Dincer and Dost model) were used to study the mass transfer behaviour of sweet potato slices with and without shrinkage during mid-infrared drying. The heat transfer flux between the emitter and sweet potato slices was also investigated. Results demonstrated that an increase in infrared intensity from 1100 W/m2 to 1400 W/m2 resulted in increased in average radiation heat flux by 3.4 times and a 15% reduction in the overall drying time. The two-term exponential model was found to be the best in predicting the drying kinetics of sweet potato slices during mid-infrared drying. The specific heat consumption varied from 0.91-4.82 kWh/kg. The effective moisture diffusivity with and without shrinkage using the Fick's diffusion model varied from 2.632 × 10-9 to 1.596 × 10-8 m2/s, and 1.24 × 10-8 to 2.4 × 10-8 m2/s using Dincer and Dost model, respectively. The obtained values of mass transfer coefficient, Biot number and activation energy varied from 5.99 × 10-6 to 1.17 × 10-5 m/s, 0.53 to 2.62, and 12.83 kJ/mol to 34.64 kJ/mol, respectively. The values obtained for Biot number implied the existence of simultaneous internal and external resistances. The findings further explained that mid-infrared intensity of 1100 W/m2 did not significantly affect the quality of sweet potato during drying, demonstrating a great potential of applying low intensity mid-infrared radiation in the drying of agricultural crops.

Increase in the free radical scavenging capability of bitter gourd by a heat-drying process.

Science.gov (United States)

Wei, Lu; Shaoyun, Wang; Shutao, Liu; Jianwu, Zhou; Lijing, Ke; Pingfan, Rao

2013-12-01

Bitter gourd (Momordica charantia Linn.) is widely regarded as one of the best remedy foods for diabetes. The positive effect of bitter gourd on diabetes has been attributed in part to the remarkable free radical scavenging activity of its boiled water extract from sun-dried fruits. It is well known that a heat process significantly influences the antioxidant activity of fresh fruits. However, the heat drying processes of bitter gourd have not been studied so far. Here, we show that the free radical scavenging capability of bitter gourd extract significantly increases after the heat drying process, while the content of flavonoids and phenols, which are generally regarded as the main antioxidant components in bitter gourd, remain unaffected. Furthermore, the content of free amino acids and the total reducing sugar were found to decrease with increasing browning index, indicating the progression of the Maillard reaction, products of which are known to possess significant antioxidant activity. Therefore, it suggests that Maillard reaction products may be the main contributors to the increase in antioxidant capability. Finally, the bitter gourd extract with the higher antioxidant activity, was shown to manifest a corresponding higher proliferation activity on NIT-1 beta-cells. These results suggest that controllable conditions in the heat-drying processing of fresh bitter gourd fruit is of significance for enhancing the total free radical scavenging capacity, beta-cell proliferation activity and possibly the anti-diabetic activity of this fruit.

Design of solar drying-plant for bulk material drying

Directory of Open Access Journals (Sweden)

Peter Horbaj

2008-11-01

Full Text Available A generally well-known high energy requirement for technological processes of drying and the fact that the world’s supplyof the conventional energy sources has considerably decreased are the decisive factors forcing us to look for some new, if possible,renewable energy sources for this process by emphasising their environmental reliability. One of the possibilities how to replace, atleast partly, the conventional energy sources – heat in a drying process is solar energy.Air-drying of bulk materials usually has a series of disadvantages such as time expenditure, drying defects in the bulk materialand inadequate final moisture content. A method that obviates or reduces the disadvantages of air-drying and, at the same time, reducesthe costs of kiln drying, is drying with solar heat. Solar energy can replace a large part of this depletable energy since solar energy cansupply heat at the temperatures most often used to dry bulk material. Solar drying-plant offer an attractive solution.

Drying characteristics and nitrogen loss of biogas digestate during drying process

Energy Technology Data Exchange (ETDEWEB)

Maurer, C.; Muller, J. [Hohenheim Univ., Stuttgart (Germany). Inst. of Agricultural Engineering, Tropical and Subtropical Group

2010-07-01

The cost of transporting biogas digestate can be decreased by reducing its water content. However, the digestate emits volatile compounds during drying. This study investigated the drying behaviour and the change of digestate composition. Drying took place in a hybrid solar/waste-heat dryer that used solar energy as well as waste heat from a combined heat and power unit (CHP) and the exhaust air of a microturbine. The experiment involved the use of 60 t of liquid digestate. Climatic conditions were measured inside and outside the drying hall. Dry matter (DM) and organic dry matter (ODM) were also measured on a daily basis. In addition, the energy consumption of waste and solar heat were recorded and related to the quantity of dried feedstock. The total nitrogen, ammonium, phosphate, potassium oxide, magnesium oxide and calcium oxide in the digestate were subjected to chemical analysis before and after the drying process. Losses of nitrogen were calculated. Specific energy consumption depended on the climatic condition. Most of the energy consumption was covered by the waste heat of the CHP. A considerable amount of nitrogen was lost during the drying process.

CFD simulations of the effect of wind on the spontaneous heating of coal stockpiles

Czech Academy of Sciences Publication Activity Database

Taraba, B.; Michalec, Zdeněk; Michalcová, V.; Blejchař, T.; Bojko, M.; Kozubková, M.

2014-01-01

Roč. 118, č. 1 (2014), s. 107-112 ISSN 0016-2361 Grant - others:GA ČR GA105/08/1414; TA ČR(CZ) TA01020351; GA MŠk(CZ) ED2.1.00/03.0100 Institutional support: RVO:68145535 Keywords : coal oxidation * spontaneous heating * CFD modelling * coal stockpile Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.520, year: 2014 http://www.sciencedirect.com/science/article/pii/S0016236113010053#

Heat and Mass Transfer in the Drying of a Cylindrical Body in an Oscillating Magnetic Field

Science.gov (United States)

Rudobashta, S. P.; Zueva, G. A.; Kartashov, É. M.

2018-01-01

A problem on the heating of a cylindrical body of infinite length in an oscillating electromagnetic field in the process of its drying has been formulated and solved analytically with account of the intermittence of irradiation of the body defined by the Heaviside unit function, the exponential-law absorption of electromagnetic energy by it, and the convective heat and mass exchange between the surface of the body and the environment having constant parameters. The intensity of evaporation of moisture from the surface of the body was determined on the basis of analytical solution of the problem on the mass transfer (moisture diffusion) in it on the assumption that the phase transformations of the body proceed near its surface. Solutions of the problem on the heating of the cylindrical body have been obtained for the cases of nonuniform and uniform distributions of its local temperature, the temperature of the body averaged over its volume, and the temperature gradient near the surface of the body. The "serviceability" of these solutions was verified on the basis of numerical simulation, with them, of the drying of a seed shaped as a cylinder under the action of an oscillating infrared radiation. As a result of the numerical simulation performed, a technological regime of drying of seeds at minimum and maximum temperatures of their heating by on oscillating infrared radiation for a definite period of time in a cycle, providing not only the drying of the seeds but also substantial improvement of their sowing properties (the sprouting energy and the germination power), has been found. It is shown that the oscillating infrared heating of seeds can be used for their drying in pseudofluidized and vibrofluidized beds.

Irradiation versus methyl bromide fumigation or heating as procedures for increasing shelf life of dry date varieties

International Nuclear Information System (INIS)

El-Samahy, S.K.; Abd El-Hady, S.A.; Swailam, H.M.

2004-01-01

The objective of this study is to evaluate the use of irradiation as an alternative method and comparing it with the traditional methods such as fumigation and heating for increasing shelf life dry date varieties. two varieties of dry dates, Malakaby and Gandilla, were obtained from Aswan, Upper Egypt and were used in this study. The irradiation was carried out with different doses of gamma rays to select the recommended dose to increase shelf life of dry dates. The fumigated, heated and irradiated samples were stored at room temperature after packaging in polyethylene plus cloth bags. The date characteristics such as insect infestation percent, weight loss, microbiological analyses, and firmness and chemical analyses were evaluated. The results obtained indicated that irradiation as a procedure for insect disinfestation and increasing shelf life of dry dates was better than both fumigation and heating methods. Where, irradiation of date fruits at dose of 1.0 kGy inhibited the insect infestation and improved the microbial quality of the date fruits during storage up to 18 months. Adding cloths to polyethylene packages raised the percentage of intact dry date fruits

Safety verification of radiation shielding and heat transfer for a model for dry

International Nuclear Information System (INIS)

Yu, Haiyan; Tang, Xiaobin; Wang, Peng; Chen, Feida; Chai, Hao; Chen, Da

2015-01-01

Highlights: • New type of dry spent fuel storage was designed. • MC method and FEM were used to verify the reliability of new storage. • Radiation shield and heat transfer both meet IAEA standards: 2 mSv/h, 0.1 mSv/h and 190 °C, 85 °C. • Provided possibilities for future implementation of this type of dry storage. - Abstract: The goal of this research is to develop a type of dry spent fuel storage called CHN-24 container, which could contain an equivalent load of 45 GWD/MTU of spent fuel after 10 years cooling. Basically, radiation shielding performance and safe removal of decay heat, which play important roles in the safety performance, were checked and validated using the Monte Carlo method and finite element analysis to establish the radiation dose rate calculation model and three-dimensional heat transfer model for the CHN-24 container. The dose rates at the surface of the container and at a distance of 1 m from the surface were 0.42 mSv/h and 0.06 mSv/h, respectively. These conform to the International Atomic Energy Agency (IAEA) radioactive material transportation safety standards 2 mSv/h and 0.1 mSv/h. The results shows that the CHN-24 container maintains its structural and material integrity under the condition of normal thermal steady-state heat transfer as well as in case of extreme fire as evinced by transient-state analysis. The temperature inside and on the surface of the container were 150.91 °C and 80 °C under normal storage conditions, which indicated that the design also conform to IAEA heat transfer safety standards of 190 °C and 85 °C

PERFORMANCE OF A FORCED CONVECTION SOLAR DRIER INTEGRATED WITH GRAVEL AS HEAT STORAGE MATERIAL FOR CHILI DRYING

Directory of Open Access Journals (Sweden)

M. MOHANRAJ

2009-09-01

Full Text Available An indirect forced convection solar drier integrated with different sensible heat storage maternal has been developed and tested its performance for drying chili under the metrological conditions of Pollachi, India. The system consists of a flat plate solar air heater with heat storage unit, a drying chamber and a centrifugal blower. Drying experiments have been performed at an air flow rate of 0.25 kg/s. Drying of chili in a forced convection solar drier reduces the moisture content from around 72.8% (wet basis to the final moisture content about 9.1% in 24 h. Average drier efficiency was estimated to be about 21%. The specific moisture extraction rate was estimated to be about 0.87 kg/kWh.

Aspects Concerning the Heating/Drying of Oak Planks in a Radiofrequency Field

Directory of Open Access Journals (Sweden)

LAZA (BULC Marcela

2013-05-01

Full Text Available Heat transfer and the evaporation of moisture from wood may be achieved with the help of high-frequency currents, depending on the dielectric properties of wood. Since wood is generally a heterogeneous material, these properties may vary depending on frequency, humidity, temperature and density. This paper presents aspects related to the numerical modeling of the process of heating or drying oak planks arranged in a13.56 MHz radiofrequency applicator, correlated with experiments.

The effect of dry spots on heat transfer in a locally heated liquid film moving under the action of gas flow in a channel

Science.gov (United States)

Zaitsev, D. V.; Tkachenko, E. M.; Bykovskaya, E. F.

2017-11-01

Intensive evaporation of a thin liquid film, moving in a flat micro-/minichannel under the action of gas flow is very promising for the use in cooling systems of modern semiconductor devices with localized heat sources of high intensity. In this work, using the high-speed visualization, the effect of the formation of dry spots on heat transfer in a locally heated liquid film shear-driven in a channel was investigated. It was found that the maximum intensity of heat removal from the heater is achieved in the mode, when the film flow continuity is broken. During the experiment the total area of dry spots increases with increasing heat flux and heater temperature, but when the heater reaches a certain temperature (≈100°C), the total area begins to decrease. However, the length of contact line increases with increasing heat flux and reaches a maximum in the pre-crisis regime. Intensive evaporation in the region of the contact line may explain the achievement of high heat fluxes in the shear-driven liquid film.

Dry heat and radiation combination effects on Aspergillus flavus Link. infecting cocoa beans

International Nuclear Information System (INIS)

Amoako-Atta, B.; Meier, H.; Odamtten, G.T.

1981-01-01

The paper deals with the effect of heat and radiation combination treatments on the control of microbial spoilage of cocoa beans caused by toxigenic Aspergillus flavus Link. The heat and radiation sources were from dry air oven heat and 60 Co gammacell 220 irradiator, respectively. The radiation doses used were either 0, 50, 100, 150 or 200 krad, with combined heat temperatures of 30, 60 or 90 0 C. At each temperature level three different exposure time intervals of either 15 min, 30 min or 60 min respectively, were used. Two reversible sequential heat/radiation combination effects were evaluated. The first sequence involved cocoa beans inoculated with A. flavus spores exposed first to dry heat at pre-determined temperature heat exposure time, followed by radiation treatment, then retention of samples in a constant humidity environmental chamber set at 80% for daily observation up to forty days post-treatment. The second sequence involved exposure of the inoculated beans first to radiation, then to heat before retention under fixed RH for observation. From their results, the authors arrive at four conclusions: first, that there is a critical radiation/heat combination range (200, 150 and 100 krad/90 0 C for 15 min) that significantly decontaminates (less than 5% mouldiness) A. flavus infected cocoa beans even under high relative humidity (80% RH) environment; second, that a temperature level of 90 0 C combined with 200, 150 or 100 krad maximizes such effect but the heat exposure time is a major factor; third, that low heat temperature ranges of 30 or 60 0 C, combined with low radiation dosages of 150 krad or below, enhance the rate of A. flavus spoilage effects of cocoa beans; and, lastly, that the sequence of exposure of the inoculated cocoa beans to heat/radiation combination influenced the spore germination; exposure to heat before radiation would sensitize the spores (200 krad/90 0 C) but results in an increased radioresistance. (author)

Generalized drying curves in conductive/convective paper drying

Directory of Open Access Journals (Sweden)

O.C. Motta Lima

2000-12-01

Full Text Available This work presents a study related to conductive/convective drying of paper (cellulose sheets over heated surfaces, under natural and forced air conditions. The experimental apparatus consists in a metallic box heated by a thermostatic bath containing an upper surface on which the paper samples (about 1 mm thick are placed. The system is submitted to ambient air under two different conditions: natural convection and forced convection provide by an adjustable blower. The influence of initial paper moisture content, drying (heated surface temperature and air velocity on drying curves behavior is observed under different drying conditions. Hence, these influence is studied through the proposal of generalized drying curves. Those curves are analyzed individually for each air condition exposed above and for both together. A set of equations to fit them is proposed and discussed.

A note on self heating and spontaneous combustion of stored sunflower seed cake and cotton seeds

International Nuclear Information System (INIS)

El-Nazir, S. M. A.; Babikir, I. H.; Shakak, M. A. S.; Sulieman, I. A.; Medani, R. M.

2012-01-01

Sunflower seed cake and cotton seed warehouses combusted spontaneously and burnt in August and November 2009, respectively, in Khartoum North industrial area. The objective of this study was to determine some of the reasons for self-heating and spontaneous combustion. Representative sample from the two warehouses were collected. Aspergillus niger, A. flavus, paecilomyces sp., Rhizopus oryzae, Absidia sp. were isolated at 37°C. Bacillus thuringiensis was isolated at 37°C and B. pantothenticus, B. circulans, B. licheniformis, B. sphaericus, B. badius, Escherichia coli and klebsiella sp. were isolated at 60°C. A decrease in soil, fiber and phosphorus and increase in free fatty acids and protein contents were detected.(Author)

Effect of cooling heat-stressed dairy cows during the dry period on insulin response.

Science.gov (United States)

Tao, S; Thompson, I M; Monteiro, A P A; Hayen, M J; Young, L J; Dahl, G E

2012-09-01

Heat stress (HT) during the dry period affects hepatic gene expression and adipose tissue mobilization during the transition period. In addition, it is postulated that HT may alter insulin action on peripheral tissues. Our objective was to evaluate the effect of cooling heat-stressed cows during the dry period on insulin effects on peripheral tissues during the transition period. Cows were dried off 46 d before expected calving and assigned to 1 of 2 treatments: HT (n = 16) or cooling (CL, n = 16). During the dry period, the average temperature-humidity index was 78, but CL cows were cooled with sprinklers and fans, whereas HT cows were not. After calving, all cows were housed and managed under the same conditions. Rectal temperatures were measured twice daily (0730 and 1430 h) and respiration rate recorded 3 times weekly during the dry period. Dry matter intake was recorded daily from dry-off to 42 d relative to calving (DRC). Body weight and body condition score were measured weekly from dry-off to 42 DRC. Milk yield and composition were recorded daily to 42 wk postpartum. Glucose tolerance tests (GTT) and insulin challenges (IC) were performed at dry-off, -14, 7, and 28 DRC in a subset of cows (HT, n = 8; CL, n = 8). Relative to HT, CL cows had lower rectal temperatures (39.3 vs. 39.0°C) in the afternoon and respiration rate (69 vs. 48 breath/min). Cows from the cooling treatment tended to consume more feed than HT cows prepartum and postpartum. Compared with HT, CL cows gained more weight before calving but lost more weight and body condition in early lactation. Cows from the cooling treatment produced more milk than HT cows (34.0 vs. 27.7 kg/d), but treatments did not affect milk composition. Treatments did not affect circulating insulin and metabolites prepartum, but CL cows had decreased glucose, increased nonesterified fatty acid, and tended to have lower insulin concentrations in plasma postpartum compared with HT cows. Cooling prepartum HT cows did not

Heat and mass transfer models to understand the drying mechanisms of a porous substrate.

Science.gov (United States)

Songok, Joel; Bousfield, Douglas W; Gane, Patrick A C; Toivakka, Martti

2016-02-01

While drying of paper and paper coatings is expensive, with significant energy requirements, the rate controlling mechanisms are not currently fully understood. Two two-dimensional models are used as a first approximation to predict the heat transfer during hot air drying and to evaluate the role of various parameters on the drying rates of porous coatings. The models help determine the structural limiting factors during the drying process, while applying for the first time the recently known values of coating thermal diffusivity. The results indicate that the thermal conductivity of the coating structure is not the controlling factor, but the drying rate is rather determined by the thermal transfer process at the structure surface. This underlines the need for ensuring an efficient thermal transfer from hot air to coating surface during drying, before considering further measures to increase the thermal conductivity of porous coatings.

Design of SMART waste heat removal dry cooling tower using solar energy

International Nuclear Information System (INIS)

Choi, Yong Jae; Jeong, Yong Hoon

2014-01-01

The 85% of cooling system are once-through cooling system and closed cycle wet cooling system. However, many countries are trying to reduce the power plant water requirement due to the water shortage and water pollution. Dry cooling system is investigated for water saving advantage. There are two dry cooling system which are direct and indirect cooling system. In direct type, turbine exhaust is directly cooled by air-cooled condenser. In indirect system, turbine steam is cooled by recirculating intermediate cooling water loop, then the loop is cooled by air-cooled heat exchanger in cooling tower. In this paper, the purpose is to remove SMART waste heat, 200MW by using newly designed tower. The possibility of enhancing cooling performance by solar energy is analyzed. The simple cooling tower and solar energy cooling tower are presented and two design should meet the purpose of removing SMART waste heat, 200MW. In first design, when tower diameter is 70m, the height of tower should be 360m high. In second design, the chimney height decrease from 360m to 180m as collector radius increase from 100m to 500m due to collector temperature enhancement by solar energy, To analyze solar cooling tower further, consideration of solar energy performance at night should be analyzed

Design of SMART waste heat removal dry cooling tower using solar energy

Energy Technology Data Exchange (ETDEWEB)

Choi, Yong Jae; Jeong, Yong Hoon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2014-10-15

The 85% of cooling system are once-through cooling system and closed cycle wet cooling system. However, many countries are trying to reduce the power plant water requirement due to the water shortage and water pollution. Dry cooling system is investigated for water saving advantage. There are two dry cooling system which are direct and indirect cooling system. In direct type, turbine exhaust is directly cooled by air-cooled condenser. In indirect system, turbine steam is cooled by recirculating intermediate cooling water loop, then the loop is cooled by air-cooled heat exchanger in cooling tower. In this paper, the purpose is to remove SMART waste heat, 200MW by using newly designed tower. The possibility of enhancing cooling performance by solar energy is analyzed. The simple cooling tower and solar energy cooling tower are presented and two design should meet the purpose of removing SMART waste heat, 200MW. In first design, when tower diameter is 70m, the height of tower should be 360m high. In second design, the chimney height decrease from 360m to 180m as collector radius increase from 100m to 500m due to collector temperature enhancement by solar energy, To analyze solar cooling tower further, consideration of solar energy performance at night should be analyzed.

HEAT TREATMENTS OF HIGH TEMPERATURE DRIED NORWAY SPRUCE BOARDS: SACCHARIDES AND FURFURALS IN SAPWOOD SURFACES

Directory of Open Access Journals (Sweden)

Olov Karlsson,

2012-02-01

Full Text Available Carbohydrates that migrate to wood surfaces in sapwood during drying might influence properties such as mould susceptibility and colour. Sugars on the surface of Norway spruce boards during various heat treatments were studied. Samples (350mmx125mmx25mm were double-stacked, facing sapwood-side outwards, and dried at 110oC to a target moisture content (MC of 40%. Dried sub-samples (80 mm x 125 mm x 25 mm were stacked in a similar way and further heated at 110oC and at 130oC for 12, 24, and 36 hours, respectively. Glucose, fructose, and sucrose as well as 5-hydroxymethylfurfural (HMF and furfural in the sapwood surface layer of treated wood were analysed using HPLC (RI- and UV-detectors. Carbohydrates degraded to a lower extent at 110oC than at 130oC. Furfural and to a larger extent HMF increased with treatment period and temperature. Heat treatment led to a decrease in lightness and hue of the sapwood surface of sub-samples, while chroma increased somewhat. Furthermore, considerably faster degradation (within a few minutes of the carbohydrates on the surface of the dried spruce boards was observed when single sub-samples were conductively hot pressed at 200oC. Treatment period and initial MC influenced the presence of the carbohydrates in wood surface as well as colour change (Eab of the hot pressed sub-samples.

Short communication: Effect of heat stress on markers of autophagy in the mammary gland during the dry period.

Science.gov (United States)

Wohlgemuth, S E; Ramirez-Lee, Y; Tao, S; Monteiro, A P A; Ahmed, B M; Dahl, G E

2016-06-01

Heat stress (HT) during the dry period compromises mammary gland (MG) growth, thus negatively affecting subsequent milk yield. Cooling during the late dry period, when mammary tissue proliferates, is a common management practice. However, it neglects MG involution during the early dry period, a process that is accomplished by both apoptosis and autophagy. Our objective was to evaluate the effect of HT on MG autophagy during the early dry period. Holstein cows were dried off ~45d before expected calving and randomly assigned to 1 of 2 treatments: HT or cooling (CL). All cows were housed in the same free stall barn during the dry period, but only the stall area for CL cows was equipped with soakers and fans. Rectal temperature and respiration rate were measured daily during the dry period. Mammary gland biopsies were collected from each cow 3d before dry-off and on d 3, 7, 14, and 22±2 after dry-off. Autophagy in the MG was determined by measuring protein expression of 2 autophagic markers, autophagy-related protein 7 and microtubule-associated protein light chain 3 (LC3). The average temperature-humidity index during the dry period was 77.7, which indicated that HT and CL cows were exposed to significant heat stress. However, the cooling system effectively alleviated heat strain in CL cows by decreasing the rectal temperature (39.0 vs. 39.4°C) and respiration rate (47.3 vs. 71.2 breaths per minute) relative to HT cows. Protein expression of autophagy-related protein 7, a marker for early autophagosome formation, did not change within or between groups. In contrast, protein expression of LC3-II, a marker of autophagosomes, and its precursor LC3-I showed a dynamic expression pattern in MG from CL cows during the early dry period. Relative to HT cows, MG from CL cows displayed higher expression of LC3-I and LC3-II on d 7 and lower expression of LC3-II on d 14 and 22 after dry-off. Collectively, our data provide a possible mechanistic explanation for the impairment of

Heat removal tests on dry storage facilities for nuclear spent fuels

International Nuclear Information System (INIS)

Wataru, M.; Saegusa, T.; Koga, T.; Sakamoto, K.; Hattori, Y.

1999-01-01

In Japan, spent fuel generated in NPP is controlled and stored in dry storage facility away-from reactor. Natural convection cooling system of the storage facility is considered advantageous from both safety and economic point of view. In order to realize this type of facility it is necessary to develop an evaluation method for natural convection characteristics and to make a rational design taking account safety and economic factors. Heat removal tests with the reduces scale models of storage facilities (cask, vault and silo) identified the the flow pattern in the test modules. The temperature and velocity distributions were obtained and the heat transfer characteristics were evaluated

Validating the Heat Stress Indices for Using In Heavy Work Activities in Hot and Dry Climates.

Science.gov (United States)

Hajizadeh, Roohalah; Golbabaei, Farideh; Farhang Dehghan, Somayeh; Beheshti, Mohammad Hossein; Jafari, Sayed Mohammad; Taheri, Fereshteh

2016-01-01

Necessity of evaluating heat stress in the workplace, require validation of indices and selection optimal index. The present study aimed to assess the precision and validity of some heat stress indices and select the optimum index for using in heavy work activities in hot and dry climates. It carried out on 184 workers from 40 brick kilns workshops in the city of Qom, central Iran (as representative hot and dry climates). After reviewing the working process and evaluation the activity of workers and the type of work, environmental and physiological parameters according to standards recommended by International Organization for Standardization (ISO) including ISO 7243 and ISO 9886 were measured and indices were calculated. Workers engaged in indoor kiln experienced the highest values of natural wet temperature, dry temperature, globe temperature and relative humidity among studied sections (Pstress index (HSI) indices had the highest correlation with other physiological parameters among the other heat stress indices. Relationship between WBGT index and carotid artery temperature (r=0.49), skin temperature (r=0.319), and oral temperature (r=0.203) was statistically significant (P=0.006). Since WBGT index, as the most applicable index for evaluating heat stress in workplaces is approved by ISO, and due to the positive features of WBGT such as ease of measurement and calculation, and with respect to some limitation in application of HSI; WBGT can be introduced as the most valid empirical index of heat stress in the brick workshops.

Exergoeconomic analyses of a gas engine driven heat pump drier and food drying process

International Nuclear Information System (INIS)

Gungor, Aysegul; Erbay, Zafer; Hepbasli, Arif

2011-01-01

Exergoeconomic analysis of a pilot scale gas engine driven heat pump (GEHP) drying system is performed based on the experimental values using Exergy, Cost, Energy and Mass (EXCEM) analysis method in this study. The performance of the drying system components is discussed, while the important system components are determined to improve the system efficiency. The performance of the drying process is also analyzed for three different medicinal and aromatic plants from the exergoeconomic point of view. A comprehensive parametric study is conducted to investigate the effect of varying dead (reference) state temperatures on exergoeconomic performance parameters for both drying system components and drying process. The correlations between the performance parameters and dead state temperatures are developed. The results have indicated that the dead state temperature affects the performance parameters, particularly the drying process parameters. Rising the dead state temperature leads to an increase in the exergy efficiencies of the drying process and a decrease in the ratio of the thermodynamic loss rate to the capital cost (R . ex ) values in a polynomial form. R . ex values of the drying process are obtained to be very higher compared to those of the drying system components.

Simultaneous Heat and Mass Transfer Model for Convective Drying of Building Material

Science.gov (United States)

Upadhyay, Ashwani; Chandramohan, V. P.

2018-04-01

A mathematical model of simultaneous heat and moisture transfer is developed for convective drying of building material. A rectangular brick is considered for sample object. Finite-difference method with semi-implicit scheme is used for solving the transient governing heat and mass transfer equation. Convective boundary condition is used, as the product is exposed in hot air. The heat and mass transfer equations are coupled through diffusion coefficient which is assumed as the function of temperature of the product. Set of algebraic equations are generated through space and time discretization. The discretized algebraic equations are solved by Gauss-Siedel method via iteration. Grid and time independent studies are performed for finding the optimum number of nodal points and time steps respectively. A MATLAB computer code is developed to solve the heat and mass transfer equations simultaneously. Transient heat and mass transfer simulations are performed to find the temperature and moisture distribution inside the brick.

A Comparison of Some Properties of Vat-Heated and Dry Skim Milk ...

African Journals Online (AJOL)

Some properties, namely; viscosity, flavour, acidity, texture, aroma and palatability of cultured yoghurt made from milk previously heated to 90OC for 30 minutes in a Vat were studied and the results compared to those of yoghurt fortified by addition of dry skim milk powder. The results showed no significant difference (P ...

Heat and mass transfer through a thick bed of cocoa beans during drying

Energy Technology Data Exchange (ETDEWEB)

Nganhou, J. [Laboratoire d' Energetique, B P 8390, ENSP Yaounde (Cameroon)

2004-07-01

This article relates to the establishment of macroscopic equations of thick and fixed hygroscopical porous medium allowing an analysis of couply phenomena of heat and mass transfers in drying operation. The drying is done through forced convection by imposing a circulation of hot air across the layer. The authors then make their study particular to the case of thick layer of cocoa beans grown in the region of Yaounde in cameroon. A study realized on a prototype constructed and tested in the laboratory enables the validation of the proposed model. (orig.)

Cellular Injuries in Cronobacter sakazakii CIP 103183T and Salmonella enterica Exposed to Drying and Subsequent Heat Treatment in Milk Powder

Science.gov (United States)

Lang, Emilie; Guyot, Stéphane; Peltier, Caroline; Alvarez-Martin, Pablo; Perrier-Cornet, Jean-Marie; Gervais, Patrick

2018-01-01

Because of the ability of foodborne pathogens to survive in low-moisture foods, their decontamination is an important issue in food protection. This study aimed to clarify some of the cellular mechanisms involved in inactivation of foodborne pathogens after drying and subsequent heating. Individual strains of Salmonella Typhimurium, Salmonella Senftenberg, and Cronobacter sakazakii were mixed into whole milk powder and dried to different water activity levels (0.25 and 0.58); the number of surviving cells was determined after drying and subsequent thermal treatments in closed vessels at 90 and 100°C, for 30 and 120 s. For each condition, the percentage of unculturable cells was estimated and, in parallel, membrane permeability and respiratory activity were estimated by flow cytometry using fluorescent probes. After drying, it was clearly observable that the percentage of unculturable cells was correlated with the percentage of permeabilized cells (responsible for 20–40% of the total inactivated bacteria after drying), and to a lesser degree with the percentage of cells presenting with loss of respiratory activity. In contrast, the percentages of unculturable cells observed after heat treatment were strongly correlated with the loss of respiratory activity and weakly with membrane permeability (for 70–80% of the total inactivated bacteria after heat treatment). We conclude that cell inactivation during drying is closely linked to membrane permeabilization and that heat treatment of dried cells affects principally their respiratory activity. These results legitimize the use of time–temperature scales and allow better understanding of the cellular mechanisms of bacterial death during drying and subsequent heat treatment. These results may also allow better optimization of the decontamination process to ensure food safety by targeting the most deleterious conditions for bacterial cells without denaturing the food product. PMID:29593704

Effect of longwall face advance rate on spontaneous heating process in the gob area - CFD modelling

Czech Academy of Sciences Publication Activity Database

Taraba, B.; Michalec, Zdeněk

2011-01-01

Roč. 90, č. 8 (2011), s. 2790-2797 ISSN 0016-2361 R&D Projects: GA ČR GA105/06/0630 Grant - others:GA ČR(CZ) GA105/08/1414 Institutional research plan: CEZ:AV0Z30860518 Keywords : coal oxidation * spontaneous heating * CFD modelling * Fluent Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 3.248, year: 2011 http://www.sciencedirect.com/science/article/pii/S0016236111001724

Single droplet drying for optimal spray drying of enzymes and probiotics

OpenAIRE

Schutyser, M.A.I.; Perdana, J.A.; Boom, R.M.

2012-01-01

Spray drying is a mild and cost-effective convective drying method. It can be applied to stabilise heat sensitive ingredients, such as enzymes and probiotic bacteria, albeit in industrial practice for example freeze drying or freezing are often preferred. The reason is that optimum drying conditions and tailored matrix formulations are required to avoid severe heat damage leading to loss in enzyme activity or reduced survival of bacteria. An overview is provided on the use of protective carbo...

Performance of Heat Pump Dryer for Kaffir Lime Leaves and Quality of Dried Products under Different Temperatures and Media

OpenAIRE

N. Poomsa-ad; K. Deejing; L. Wiset

2011-01-01

This research is to study the performance of heat pump dryer for drying of kaffir lime leaves under different media and to compare the color values and essential oil content of final products after drying. In the experiments, kaffir lime leaves were dried in the closed-loop system at drying temperatures of 40, 50 and 60 oC. The drying media used in this study were hot air, CO2 and N2 gases. The velocity of drying media in the drying chamber was 0.4 m/s with bypass ratio o...

Vial freeze-drying, part 1: new insights into heat transfer characteristics of tubing and molded vials.

Science.gov (United States)

Hibler, Susanne; Wagner, Christophe; Gieseler, Henning

2012-03-01

In order to optimize a freeze-drying cycle, information regarding the heat transfer characteristics of the container system is imperative. Two most recently developed tubing (TopLyo™) and molded (EasyLyo™) vial designs were compared with a standard serum tubing and molded vial, a polymer vial (TopPac™), and an amber molded EasyLyo™. In addition, the impact of methodology on the determination of reliable vial heat transfer coefficient (K(v) ) data is examined in detail. All K(v) s were gravimetrically determined by sublimation tests with pure water at 50, 100, 200, and 400 mTorr. In contrast to the traditional assumption that molded vials exhibit inefficient heat transfer characteristics, these vials showed a very similar performance compared with their serum tubing counterparts in the relevant pressure range for freeze-drying. At 100 mTorr, the TopLyo™ center vials show only 4% higher K(v) values than the EasyLyo™ center vials. All glass vials outmatch the polymer vial in terms of heat transfer, up to 30% elevated heat transfer for the TopLyo™ center vials at 400 mTorr. Sublimation tests have demonstrated to be a valuable tool to investigate the heat transfer characteristics of vials, but results are dependent on methodology. New developments in molded vial manufacturing lead to improved heat transfer performance. Copyright © 2011 Wiley Periodicals, Inc.

Humidification performance of humidifying devices for tracheostomized patients with spontaneous breathing: a bench study.

Science.gov (United States)

Chikata, Yusuke; Oto, Jun; Onodera, Mutsuo; Nishimura, Masaji

2013-09-01

Heat and moisture exchangers (HMEs) are commonly used for humidifying respiratory gases administered to mechanically ventilated patients. While they are also applied to tracheostomized patients with spontaneous breathing, their performance in this role has not yet been clarified. We carried out a bench study to investigate the effects of spontaneous breathing parameters and oxygen flow on the humidification performance of 11 HMEs. We evaluated the humidification provided by 11 HMEs for tracheostomized patients, and also by a system delivering high-flow CPAP, and an oxygen mask with nebulizer heater. Spontaneous breathing was simulated with a mechanical ventilator, lung model, and servo-controlled heated humidifier at tidal volumes of 300, 500, and 700 mL, and breathing frequencies of 10 and 20 breaths/min. Expired gas was warmed to 37°C. The high-flow CPAP system was set to deliver 15, 30, and 45 L/min. With the 8 HMEs that were equipped with ports to deliver oxygen, and with the high-flow CPAP system, measurements were taken when delivering 0 and 3 L/min of dry oxygen. After stabilization we measured the absolute humidity (AH) of inspired gas with a hygrometer. AH differed among HMEs applied to tracheostomized patients with spontaneous breathing. For all the HMEs, as tidal volume increased, AH decreased. At 20 breaths/min, AH was higher than at 10 breaths/min. For all the HMEs, when oxygen was delivered, AH decreased to below 30 mg/L. With an oxygen mask and high-flow CPAP, at all settings, AH exceeded 30 mg/L. None of the HMEs provided adequate humidification when supplemental oxygen was added. In the ICU, caution is required when applying HME to tracheostomized patients with spontaneous breathing, especially when supplemental oxygen is required.

The relative nutritive value of irradiated spray-dried blood powder and heat-sterilized blood meal as measured in combination with whey protein

International Nuclear Information System (INIS)

Downes, T.E.H.; Nourse, L.D.; Siebrits, F.K.; Hastings, J.W.

1987-01-01

A method of processing blood meal in which nutritive value of the protein is preserved is described, since appreciable losses occur in the nutritive value of the protein when prepared by heat sterilization with drying at atmospheric pressure in steam jacketed vessels. Blood was spray dried and irradiated at an intensity of 10 kGy. Collectively the heat of spray drying and irradiation was effective in killing both the virus plaque-forming units and the bacteria, thus producing a commercially acceptable sterile product of higher nutritive value. The relative nutritive values (RNV) of 50:50 protein were 0,56 for whey protein concentrate plus heat-sterilized blood meal and 0.90 for whey protein concentrate plus irradiated spray-dried blood powder. Whey protein concentrate used as a control has a RNV of 1,0

The effects of combined treatment of irradiation and heat on bacteria escherichia coli and sarcina lutea in dry condition

International Nuclear Information System (INIS)

Nikham; Hilmy, Nazly

1987-01-01

The effects of combination treatment of irradiation and heat on bacteria escherichia coli and sarcina lutea in dry condition. Investigation on the effects of combined irradiation + heat and heat + irradiation treatments have been carried out i.e. at the doses of 0; 1.0; 1.5; and 2.0 kGy with heating at 50 0 C for 10; 20; and 30 minutes on escherichia coli B/r, escherichia coli from sludge and sarcine lutea. Samples of bacteria were prepared in dry condition by using sterile fine sand as carrier. Irradiation was done in aerobic condition with RH 90% and the time range between irradiation and heating was not more than 2 hours. The results showed that the D 10 value did not give significant difference between the combined irradiation + heat, and heat + irradiation treatments for the 3 species of bacteria, compared to irradiation only (p 0.05). Doses of 1.0 and 1.5 kGy combined with heating at 50 0 C for 10 and 20 minutes gave better results compared to irradiation only. 17 refs

Enhanced high energy efficient steam drying of algae

International Nuclear Information System (INIS)

Aziz, Muhammad; Oda, Takuya; Kashiwagi, Takao

2013-01-01

Highlights: • Brown algae drying processes based on heat circulation technology (HC) were proposed. • HC was developed on exergy recovery through exergy elevation and heat pairing. • The energy efficiency of the proposed drying processes was evaluated. • Significant reduction of energy input and CO 2 emission in drying is readily achieved. - Abstract: State-of-the-art brown algae drying processes based on heat circulation technology were proposed, and their performance with respect to energy consumption was evaluated. Heat circulation technology was developed using the principle of exergy recovery performed through exergy elevation and effective heat pairing for both sensible and latent heat. Two steam drying processes based on heat circulation technology for algae drying were proposed, involving heat circulation with or without steam recirculation. The proposed processes were compared with the conventional heat recovery system employing heat cascade technology. Brown algae Laminaria japonica was selected as the test sample. From the results, it is very clear that both proposed drying processes can reduce the required drying energy significantly by up to 90% of that required in conventional heat recovery drying. Furthermore, the temperature–enthalpy diagram for each process shows that in heat circulation technology based drying, the curves of both hot and cold streams are almost parallel, resulting in the minimization of exergy losses

Reduced heat stress in offices in the tropics using solar powered drying of the supply air

DEFF Research Database (Denmark)

Gunnarsen, Lars; Santos, A M B

2002-01-01

air may facilitate personal cooling by increased evaporation of sweat. Heat acclimatized people with efficient sweating may in particular benefit from this cooling. A prototype solar powered supply system for dried-only air was made. Air from the system was mixed with room air, heated to six different...... content of room air, temperature of supply air and moisture content of supply air was developed based on the experiments. Reduction of moisture content in the supply air by 1.6 g/kg had the same effect as lowering the operative temperature by 1 degree C. The solar-powered system for supplying dry air...... is a low-cost alternative to traditional air conditioning in hot and humid regions....

Acceleration of peat drying by intensifying the heat and mass transfer; Turpeen kuivumisen nopeuttaminen laemmoen- ja aineensiirtoa tehostamalla

Energy Technology Data Exchange (ETDEWEB)

Hillebrand, K.

1996-12-31

The efficiency of peat production can be increased by intensifying peat drying. To intensify drying one has to know the effects of the different factors affecting the heat and mass transfer in the drying layer and in the soil. The objective of the study is to increase the degree of utilization of solar energy in drying of peat from the present level of 30% to 40% of the total incoming solar energy. In this way it is possible to reduce the peat production costs about 10%. A numerical drying model has been developed which describes the transfer of liquid water, water vapor and heat in the drying layer and in the soil. In addition, the interaction between the atmosphere and the drying layer, as well as the rainfall interception by the layer, infiltration, evaporation, and drainage have been taking into account. Daily input requirements include global solar radiation, air temperature and relative humidity, wind speed and precipitation. In addition to the weather data one has to know the characteristics of the drying layer and the soil. The numerical drying model was also used to study the effect of soil frost on peat drying and the possibilities to hinder the frost formation. Producing peat on the field which is still partly frozen, the drying of peat takes 10 - 25% longer time than under normal conditions, which means 5 - 25 hours longer drying period. By forming a porous, insulating layer on the top of the soil surface, one can hinder the frost formation significantly. Raising the groundwater level prevents, however, only a little the frost formation in peat soil

The Spontaneous Combustion of Railway Ties and Asphalt Shingles

Science.gov (United States)

Leslie, Geoffrey

Many Low Carbon Fuels (LCFs) present unknown spontaneous combustion risks, which must be quantified before their use as fossil fuel replacements. Wood and coal spontaneous combustion is well understood; however, LCFs weather, and subsequent chemical changes could affect their spontaneous combustion properties. LCF spontaneous combustion could lead to accidental fires with possible loss of life, limb and property. The spontaneous combustion risks of two LCFs, discarded creosote-treated wooden railway ties and roofing asphalt shingles, were investigated with calorimetry and heat transfer experiments. Chemical changes due to weathering were studied with pyrolysis-Gas Chromatography/Mass Spectrometry (py-GC/MS). Creosote-treated wooden railway tie dust, roofing asphalt shingle particles, poplar wood pellets, and petroleum coke self-heating were studied with isothermal calorimetry. Railway tie dust and asphalt shingle heat transfer were characterized with a guarded hot plate. Petroleum coke self-heating was consistent with coal, while both poplar pellets and railway tie dust were found to be more reactive compared to oven test results of similar materials. The observed increase in reactivity was probably a result of significant moisture contenint in the pellet and railway tie dust. Critical conditions for spontaneous combustion were evaluated with the Frank-Kamenetskii parameter, assuming an ambient temperature of 40°C and constant moisture content. Kamenetskii calculations indicate that a 1.6 m cube of railway tie dust, or a 58 m cube of asphalt particles, would be unstable and combust. LCF chemistry may have been affected by weathering, which would cause chemical changes that affect their spontaneous combustion properties. Therefore, railway tie wood and roofing asphalt shingle chemistry were investigated by identifying products of 250° and 550°C pyrolysis with py-GC/MS. Railway tie wood pyrolyzates did not show signs of weathering; in contrast, asphalt pyrolysis

Vibro-fluidized bed heat pump drying of mint leaves with respect to phenolic content, antioxidant activity, and color indices

Directory of Open Access Journals (Sweden)

Ataei Ardestani Seyed Majid

2015-01-01

Full Text Available Because of high porosity and stickiness of mint leaves, they could not be fluidized well during fluidization. In this study, a vibro-fluidized bed dryer assisted heat pump system was designed and fabricated to overcome this problem. The drying experiments were carried out at temperatures of 40, 50 and 60 °C. The quality of the dehydrated samples was assessed based on color indices, antioxidant activity, and total phenolic content. Drying process primarily occurred in falling rate period. The effective coefficient of moisture transfer of the samples was increased with air temperature and varied from 4.26656×10-11 to 2.95872×10-10 m2 s-1 for heat pump drying (HPD method, and 3.71918×10-11 to 1.29196×10-10 m2 s-1 for none-heat pump drying (NHPD method. The color indices for temperatures of 40 and 50 °C were very close to each other, whereas by increasing temperature to 60 °C, a remarkable loss of green color was observed. The highest phenolic content was found in methanolic extract for HPD at 60 °C, and NHPD at 50 °C contained the lowest amount of phenolic compounds. NHPD treatments showed lower antioxidant activity compared to HPD treatments at the same temperature due to the longer drying times.

Study of caprine bones after moist and dry heat processes by X-ray diffraction

International Nuclear Information System (INIS)

Barbosa, Caroline M.; Azeredo, Soraia R.; Lopes, Ricardo T.; Souza, Sheila M.F.M de

2013-01-01

Bone tissue is a biological material composed of hydroxyapatite (HAp) and collagen matrix. The bone X-ray diffraction (XRD) pattern presents characteristics of the hydroxyapatite crystallography planes. This paper presents the characterization by X-ray diffraction of caprine bone powder pattern and the comparison of this pattern with moist or dry heat cooked bone patterns. The parameters chosen to characterize the X-ray diffraction peaks were: angular position (2θ), full width at half maximumt (FWHM), and relative intensity (I rel ). The X-ray diffraction patterns were obtained with a Shimadzu XRD-6000 diffractometer. The caprine bone XRD pattern revealed a significant correlation of several crystallographic parameters (lattice data) with hydroxyapatite. The profiles of the three bone types analyzed presented differences. The study showed as small angular displacement (decrease of the 2θ angle) of some peaks was observed after moist and dry heat cooking processes. The characterization of bone tissue aimed to contribute to future analysis in the field of archeology. (author)

Study of caprine bones after moist and dry heat processes by X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Barbosa, Caroline M., E-mail: carolmattosb@yahoo.com.br [Instituto de Arqueologia Brasileira (IAB), Belford Roxo, RJ (Brazil); Azeredo, Soraia R.; Lopes, Ricardo T., E-mail: soraia@lin.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/LIN/UFRJ), Rio de Janeiro, RJ (Brazil). Laboratorio de Instrumentacao Nuclear; Souza, Sheila M.F.M de, E-mail: sferraz@ensp.fiocruz.br [Fundacao Oswaldo Cruz (ENSP/FIOCRUZ), Rio de Janeiro, RJ (Brazil). Escola Nacional de Saude Publica Sergio Arouca

2013-07-01

Bone tissue is a biological material composed of hydroxyapatite (HAp) and collagen matrix. The bone X-ray diffraction (XRD) pattern presents characteristics of the hydroxyapatite crystallography planes. This paper presents the characterization by X-ray diffraction of caprine bone powder pattern and the comparison of this pattern with moist or dry heat cooked bone patterns. The parameters chosen to characterize the X-ray diffraction peaks were: angular position (2θ), full width at half maximumt (FWHM), and relative intensity (I{sub rel}). The X-ray diffraction patterns were obtained with a Shimadzu XRD-6000 diffractometer. The caprine bone XRD pattern revealed a significant correlation of several crystallographic parameters (lattice data) with hydroxyapatite. The profiles of the three bone types analyzed presented differences. The study showed as small angular displacement (decrease of the 2θ angle) of some peaks was observed after moist and dry heat cooking processes. The characterization of bone tissue aimed to contribute to future analysis in the field of archeology. (author)

Mixing systems for wet and dry plumes and cleaning equipment for the heat exchangers of the dry section. Two indispensible components of an effective and safe hybrid cooling tower

International Nuclear Information System (INIS)

Alt, W.

1990-01-01

At first glance, the hybrid cooling tower seems to be an ingenious combination of the well known components of an evaporative cooling tower and a dry cooling tower. The calculation of the air mass flows for both the wet and dry sections required to achieve an invisible plume does not represent an unsolvable problem to the engineer experienced in thermodynamics. The same also applies to the dimensioning of the heat exchangers and cooling fills. The hybrid cooling tower requires a well designed mixing system in order to ideally mix, the dry plume into the wet plume. If the cooling tower proves its efficiency during commissioning it is important that the ratio of the performance of the wet section to that of the dry section be maintained also in the long term. The performance of the fill in a wet cooling tower is consistently stable. Dirt deposits can form very quickly on the inner and outer surfaces of the heat exchangers of the dry section. In this case the thermal resistance increases rapidly. The respective performance of the wet and dry sections is then no longer balanced and the invisibility of the plume is no longer assured. This can be avoided by providing appropriate cleaning equipment

Predictive modeling of infrared radiative heating in tomato dry-peeling process: Part II. Model validation and sensitivity analysis

Science.gov (United States)

A predictive mathematical model was developed to simulate heat transfer in a tomato undergoing double sided infrared (IR) heating in a dry-peeling process. The aims of this study were to validate the developed model using experimental data and to investigate different engineering parameters that mos...

Dry-heat inactivation of "Mycobacterium canettii".

Science.gov (United States)

Aboubaker Osman, Djaltou; Garnotel, Eric; Drancourt, Michel

2017-06-09

"Mycobacterium canettii" is responsible for non-transmissible lymph node and pulmonary tuberculosis in persons exposed in the Horn of Africa. In the absence of direct human transmission, contaminated water and foodstuffs could be sources of contamination. We investigated the dry-heat inactivation of "M. canettii" alone and mixed into mock-infected foodstuffs by inoculating agar cylinders and milk with 10 4 colony-forming units of "M. canettii" CIPT140010059 and two "M. canettii" clinical strains with Mycobacterium tuberculosis H37Rv as a control. Exposed to 35 °C, M. tuberculosis H37Rv, "M canettii" CIPT140010059 and "M. canettii" 157 exhibited a survival rate of 108, 95 and 81%, which is significantly higher than that of "M. canettii" 173. However, all tested mycobacteria tolerated a 90-min exposure at 45 °C. In the foodstuff models set at 70 °C, no growing mycobacteria were visualized. This study supports the premise that "M. canettii" may survive up to 45 °C; and suggests that contaminated raw drinks and foodstuffs but not cooked ones may be sources of infection for populations.

Contribution to the study of the exploitation of heat from hot and dry rocks

International Nuclear Information System (INIS)

Bernaudat, Francois

1983-01-01

In its first part, this research thesis presents the basic concept of geothermal energy in hot and dry rocks, and describes various experiments performed in the USA, Great-Britain and Germany. The ENERGEROC project is then addressed in detail. The second part introduces models of heat transfer. The author proposes a detailed description of the different steps of the preliminary phase of the ENERGEROC project, and of interpretations obtained by using the models. Experimental results of the ENERGEROC project and of other projects are discussed. The last part addresses the extrapolation of the thermal behaviour of a hot-dry rock system

The effect of sublethal injury by heating, freezing, drying and gamma-radiation on the duration of the lag phase of Salmonella typhimurium

International Nuclear Information System (INIS)

Mackey, B.M.; Derrick, C.M.

1982-01-01

The duration of the lag phase of Salmonella typhimurium surviving heat, freezing, drying and gamma-radiation was used to indicate the time needed to repair sublethal injury. Following equivalent lethal treatments, heat and freeze-injured cells needed longer to repair than those injured by drying or gamma-radiation. Measurement of repair on membrane filters showed that in a heat-injured population having a lag time of 9 h, some individual cells needed up to 14 h to recover maximum tolerance to 3% NaCl. (author)

Temperature Control of Heating Zone for Drying Process: Effect of Air Velocity Change

Directory of Open Access Journals (Sweden)

Wutthithanyawat Chananchai

2016-01-01

Full Text Available This paper proposes a temperature control technique to adjust air temperature in a heating zone for drying process. The controller design is achieved by using an internal model control (IMC approach. When the IMC controller parameters were designed by calculating from an actual process transfer function estimated through an open-loop step response with input step change from 50% to 60% at a reference condition at air velocity of 1.20 m/s, the performance of temperature controller was experimentally tested by varying an air velocity between 1.32 m/s and 1.57 m/s, respectively. The experimental results showed that IMC controller had a high competency for controlling the drying temperature.

Single droplet drying for optimal spray drying of enzymes and probiotics

NARCIS (Netherlands)

Schutyser, M.A.I.; Perdana, J.A.; Boom, R.M.

2012-01-01

Spray drying is a mild and cost-effective convective drying method. It can be applied to stabilise heat sensitive ingredients, such as enzymes and probiotic bacteria, albeit in industrial practice for example freeze drying or freezing are often preferred. The reason is that optimum drying conditions

Assessing Energy Efficiency of Compression Heat Pumps in Drying Processes when Zeotropic Hydrocarbon Mixtures are Used as Working Agents

Directory of Open Access Journals (Sweden)

Shurayts Alexander

2016-01-01

Full Text Available Presents the results of studies of innovative materials in the field of renewable energy.The paper proposes a design and a formula for assessing energy efficiency of the heat pump air dryer, which uses zeotropic hydrocarbon mixtures of saturated hydrocarbons as a working agent and applies the principle of a counter-current heat exchanger with a variable temperature of both the working and the drying agents. Energy efficiency of the heat pump is achieved by means of obtaining a greater part of heat from renewable energy sources, in this case by cooling the air and condensing the water vapors in the heat pump. A conducted analysis identified correlations in establishing the marginal real coefficient of performance of the compression heat pump dryer running on zeotropic hydrocarbon mixtures and operating a cycle with variable temperatures of both the working and the drying agent in the evaporator and the condenser of the heat pump. According to the established correlations, the marginal real coefficient of performance of the compression heat pump dryers running on zeotropic hydrocarbon mixtures of 40 mol% of R600a and 60 mol% of R601 is 1.92 times higher than that of the same dryers running on only R600 (n-butane.

Allowable peak heat-up cladding temperature for spent fuel integrity during interim-dry storage

Directory of Open Access Journals (Sweden)

Ki-Nam Jang

2017-12-01

Full Text Available To investigate allowable peak cladding temperature and hoop stress for maintenance of cladding integrity during interim-dry storage and subsequent transport, zirconium alloy cladding tubes were hydrogen-charged to generate 250 ppm and 500 ppm hydrogen contents, simulating spent nuclear fuel degradation. The hydrogen-charged specimens were heated to four peak temperatures of 250°C, 300°C, 350°C, and 400°C, and then cooled to room temperature at cooling rates of 0.3 °C/min under three tensile hoop stresses of 80 MPa, 100 MPa, and 120 MPa. The cool-down specimens showed that high peak heat-up temperature led to lower hydrogen content and that larger tensile hoop stress generated larger radial hydride fraction and consequently lower plastic elongation. Based on these out-of-pile cladding tube test results only, it may be said that peak cladding temperature should be limited to a level < 250°C, regardless of the cladding hoop stress, to ensure cladding integrity during interim-dry storage and subsequent transport.

The dry-heat loss effect of melt-spun phase change material fibres.

Science.gov (United States)

Tjønnås, Maria Suong; Færevik, Hilde; Sandsund, Mariann; Reinertsen, Randi E

2015-01-01

Phase change materials (PCM) have the ability to store latent heat when they change phases, a property that gives clothing that incorporates PCM its cooling effect. This study investigated the effect of dry-heat loss (cooling) of a novel melt-spun PCM fibre on the basis of the area covered, mass, the latent heat of fusion and melting temperature, compared to a known PCM clothing product. PCM fibres with melting temperatures of 28.4 and 32.0°C and PCM packs with melting temperatures of 28.0 and 32.0°C were studied. The results showed that the PCM fibres had a larger initial peak cooling effect than that of the PCM packs. The duration of the cooling effect of PCM fibres was primarily dependent on the PCM mass and the latent heat of fusion capacity, and secondly on the covered area and melting temperature of the PCM. This study investigates the cooling effect of PCM fibres on a thermal manikin. The PCM fibres had a high but short-lasting cooling effect. This study contributes to the knowledge of how the body's temperature regulation may be affected by the cooling properties of clothing that incorporates PCM.

Viability of G4 after Spray-Drying and Freeze-Drying

Directory of Open Access Journals (Sweden)

Stephenie Wong

2010-01-01

Full Text Available Viability of Bifidobacterium pseudocatenulatum G4 following spray-drying and freeze-drying in skim milk was evaluated. After spray-drying, the strain experienced over 99% loss in viability regardless of the air outlet temperature (75 and 85 °C and the heat-adaptation temperature (45 and 65 °C, 30 min. The use of heat-adaptation treatment to improve the thermotolerance of this strain was ineffective. On the other hand, the strain showed a superior survival at 71.65%–82.07% after freeze-drying. Viable populations of 9.319–9.487 log 10 cfu/g were obtained when different combinations of skim milk and sugar were used as cryoprotectant. However, the addition of sugars did not result in increased survival during the freeze-drying process. Hence, 10% (w/v skim milk alone is recommended as a suitable protectant and drying medium for this strain. The residual moisture content obtained was 4.41% ± 0.44%.

A dry-spot model of critical heat flux and transition boiling in pool and subcooled forced convection boiling

International Nuclear Information System (INIS)

Ha, Sang Jun

1998-02-01

A new dry-spot model for critical heat flux (CHF) is proposed. The new concept for dry area formation based on Poisson distribution of active nucleation sites and the critical active site number is introduced. The model is based on the boiling phenomena observed in nucleate boiling such as Poisson distribution of active nucleation sites and formation of dry spots on the heating surface. It is hypothesized that when the number of bubbles surrounding one bubble exceeds a critical number, the surrounding bubbles restrict the feed of liquid to the microlayer under the bubble. Then a dry spot of vapor will form on the heated surface. As the surface temperature is raised, more and more bubbles will have a population of surrounding active sites over the critical number. Consequently, the number of the spots will increase and the size of dry areas will increase due to merger of several dry spots. If this trend continues, the number of effective sites for heat transport through the wall will diminish, and CHF and transition boiling occur. The model is applicable to pool and subcooled forced convection boiling conditions, based on the common mechanism that CHF and transition boiling are caused by the accumulation and coalescences of dry spots. It is shown that CHF and heat flux in transition boiling can be determined without any empirical parameter based on information on the boiling parameters such as active site density and bubble diameter, etc., in nucleate boiling. It is also shown that the present model well represents actual phenomena on CHF and transition boiling and explains the mechanism on how parameters such as flow modes (pool or flow) and surface wettability influence CHF and transition boiling. Validation of the present model for CHF and transition boiling is achieved without any tuning parameter always present in earlier models. It is achieved by comparing the predictions of CHF and heat flux in transition boiling using measured boiling parameters in nucleate

Investigation of Pear Drying Performance by Different Methods and Regression of Convective Heat Transfer Coefficient with Support Vector Machine

Directory of Open Access Journals (Sweden)

Mehmet Das

2018-01-01

Full Text Available In this study, an air heated solar collector (AHSC dryer was designed to determine the drying characteristics of the pear. Flat pear slices of 10 mm thickness were used in the experiments. The pears were dried both in the AHSC dryer and under the sun. Panel glass temperature, panel floor temperature, panel inlet temperature, panel outlet temperature, drying cabinet inlet temperature, drying cabinet outlet temperature, drying cabinet temperature, drying cabinet moisture, solar radiation, pear internal temperature, air velocity and mass loss of pear were measured at 30 min intervals. Experiments were carried out during the periods of June 2017 in Elazig, Turkey. The experiments started at 8:00 a.m. and continued till 18:00. The experiments were continued until the weight changes in the pear slices stopped. Wet basis moisture content (MCw, dry basis moisture content (MCd, adjustable moisture ratio (MR, drying rate (DR, and convective heat transfer coefficient (hc were calculated with both in the AHSC dryer and the open sun drying experiment data. It was found that the values of hc in both drying systems with a range 12.4 and 20.8 W/m2 °C. Three different kernel models were used in the support vector machine (SVM regression to construct the predictive model of the calculated hc values for both systems. The mean absolute error (MAE, root mean squared error (RMSE, relative absolute error (RAE and root relative absolute error (RRAE analysis were performed to indicate the predictive model’s accuracy. As a result, the rate of drying of the pear was examined for both systems and it was observed that the pear had dried earlier in the AHSC drying system. A predictive model was obtained using the SVM regression for the calculated hc values for the pear in the AHSC drying system. The normalized polynomial kernel was determined as the best kernel model in SVM for estimating the hc values.

A Preliminary Study on Rock Bed Heat Storage from Biomass Combustion for Rice Drying

Science.gov (United States)

Nelwan, L. O.; Wulandani, D.; Subrata, I. D. M.

2018-05-01

One of the main constraints of biomass fuel utilization in a small scale rice drying system is the operating difficulties related to the adjustment of combustion/feeding rate. Use of thermal storage may reduce the problem since combustion operation can be accomplished in a much shorter time and then the use of heat can be regulated by simply adjusting the air flow. An integrated biomass furnace-rock bed thermal storage with a storage volume of 540 L was designed and tested. There were four experiments conducted in this study. Charging was performed within 1-2 hours with a combustion rate of 11.5-15.5 kg/h. In discharging process, the mixing of air passing through the rock bed and ambient air were regulated by valves. Without adjusting the valve during the discharging process, air temperature increased up to 80°C, which is not suitable for rice batch drying process. Charging with sufficiently high combustion rate (14 kg/h) within 1 hour continued by adjusting the valve during discharging process below 60°C increased the discharge-charge time ratio (DCTR) up to 5.33 at average air temperature of 49°C and ambient temperature of 33°C.The efficiency of heat discharging was ranged from 34.5 to 45.8%. From the simulation, as much as 156.8-268.8 kg of rice was able to be dried by the discharging conditions.

Method and apparatus for in-situ drying investigation and optimization of slurry drying methodology

Science.gov (United States)

Armstrong, Beth L.; Daniel, Claus; Howe, Jane Y.; Kiggans, Jr, James O.; Sabau, Adrian S.; Wood, III, David L.; Kalnaus, Sergiy

2016-05-10

A method of drying casted slurries that includes calculating drying conditions from an experimental model for a cast slurry and forming a cast film. An infrared heating probe is positioned on one side of the casted slurry and a thermal probe is positioned on an opposing side of the casted slurry. The infrared heating probe may control the temperature of the casted slurry during drying. The casted slurry may be observed with an optical microscope, while applying the drying conditions from the experimental model. Observing the casted slurry includes detecting the incidence of micro-structural changes in the casted slurry during drying to determine if the drying conditions from the experimental model are optimal.

Compressive strength measurements of hybrid dental composites treated with dry heat and light emitting diodes (LED post cure treatment

Directory of Open Access Journals (Sweden)

Jenny Krisnawaty

2014-11-01

Full Text Available Hybrid composites are mostly used on large cavities as restorative dental materials, whether it is used directly or indirectly. The mechanical properties of composite resin shall increase if it is treated with post cure treatment. The aim of this study is to evaluate compressive strength differences between dry heat and Light Emitting Diodes (LED treatment on the hybrid dental composite. A quasi-experimental was applied on this research with a total of 30 samples that were divided into two groups. Each sample was tested using LLOYD Universal Testing Machine with 1 mm/min speed to evaluate the compressive strength. The compressive strength results were marked when the sample was broken. The results of two groups were then analyzed using t-test statistical calculation. The results of this study show that post cure treatment on hybrid composite using LED light box (194.138 MPa was lower than dry heat treatment (227.339 MPa, which was also significantly different from statistical analysis. It can be concluded that compressive strength of LED light box was lower than dry heat post-cure treatment on the hybrid composite resin.

Effect of microwave freeze drying on quality and energy supply in drying of barley grass.

Science.gov (United States)

Cao, Xiaohuang; Zhang, Min; Mujumdar, Arun S; Zhong, Qifeng; Wang, Zhushang

2018-03-01

Young barley grass leaves are well-known for containing the antioxidant substances flavonoid and chlorophyll. However, low product quality and energy efficiency exist with respect to the dehydration of barley grass leaves. To improve energy supply and the quality of barley grass, microwave heating instead of contact heat was applied for the freeze drying of barley grass at a pilot scale at 1, 1.5 and 2 W g -1 , respectively; After drying, energy supply and quality parameters of color, moisture content, chlorophyll, flavonoids, odors of dried barley grass were determined to evaluate the feasibility of the study. Microwave freeze drying (MFD) allowed a low energy supply and high contents of chlorophyll and flavonoids. A lightness value of 60.0, a green value of -11.5 and an energy supply of 0.61 kW h -1  g -1 were observed in 1.5 W g -1 MFD; whereas drying time (7 h) decreased by 42% compared to contact heating. Maximum content of flavonoid and chlorophyll was 11.7 and 12.8 g kg -1 barley grass. Microwave heating leads to an odor change larger than that for contact heating observed for the freeze drying of barley grass. MFD retains chlorophyll and flavonoids, as well as colors and odors of samples, and also decreases energy consumption in the freeze drying of barley grass. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Modeling the effect of seal leakage on spontaneous heating in a longwall gob area

Energy Technology Data Exchange (ETDEWEB)

Smith, A.C.; Yuan, L. [National Inst. for Occupational Safety and Health, Pittsburgh, PA (United States). Office of Mine Safety and Health Research

2010-07-01

Three coal mines in the United States with a history of spontaneous combustion use a bleederless ventilation system as a control measure. In a bleederless system, one of the headgate entries is used as the tailgate entry of the succeeding panel and is isolated from the gob of the active panel by gob seals that are installed in the headgate entry as the face advances. An active longwall panel using a Y-type bleederless ventilation system was simulated in this study. As longwall mining progresses, some seals are known to leak. Computational fluid dynamics (CFD) simulations were performed to study the effect of seal leakage on spontaneous heating of coal in the longwall gob area. The simulation results showed that under typical bleederless ventilation conditions, the maximum temperature in the gob increased with an increase in leakage rate. The maximum temperature occurred at the headgate side corner at the back end of the panel. When only 1 or 2 seals were leaking, the maximum temperature occurred around the seal. The results demonstrate that complex interactions between pressure differential and gob permeability at different locations in the gob cause ventilation pathways. The interactions depend greatly on gob permeability and seal leakage rates. 8 refs., 1 tab., 14 figs.

Heat flow and radioactivity studies in the Ross Island-dry valley area, Antarctica and their tectonic implications

International Nuclear Information System (INIS)

Bucher, G.J.

1980-01-01

In conjunction with the Dry Valley Drilling Project, the University of Wyoming conducted heat flow and basement radioactivity studies in the Ross Island-dry valley area of southern Victoria Land, Antarctica. This part of Antarctica is characterized by late Cenozoic alkaline basaltic volcanism and uplift. Six heat flow (q) values for the area range from 1.4 to 2.0 HFU, with a mean value of 1.7 HFU. Radioactive heat production (A) values for basement rocks from the dry valleys range from 2.2 to 4.1 HGU, with a mean value of 3.0 HGU. The combined q-A data imply that this area is a zone of high reduced heat flow, similar to the Basin and Range province in the western United States and other zones of late Cenozoic tectonof Antarctica is probably in the range of 1.2 to 1.6 HFU, which is about 50 to 100% higher than the reduced flux which characterizes stable continental areas. The results of the transient conductive models presented herein imply that the high flux in this part of Antarctica cannot be explained by the residual thermal effects of a major episode of lithospheric thinning associated with the generation of the Ferrar Dolerites. The correlation between steady conductive thermal models and the late Cenozoic, silica-undersaturated, alkaline basalts of the region is similarly obscure. For example, purely conductive steady-state temperature-depth models predict partial melting at depths of only 45 to 50 km in the mantle, whereas geochemical data for the volcanic units are consistent with the basalts being generated at depths of at least 60 to 80 km

Modeling coupled heat and mass transfer during drying in tape casting with a simple ceramics-water system

DEFF Research Database (Denmark)

Jabbari, Masoud; Hattel, Jesper

2016-01-01

process of thin sheets produced by the tape casting process. The rate of mass loss in the drying process is a key factor that often is of interest, as it affects the final properties of the tapes. The 1D heat conduction equation is solved numerically to obtain the temperature field in a ceramic sheet...... dominant since the fraction of water approaches zero. The developed model is used to simulate a simple test for the drying process. The drying rate is simply calculated by examining the water content in each time step. It is found that the mass loss due to the evaporation is increasing close to linearly...

Introduction to heat transfer

International Nuclear Information System (INIS)

Weisman, J.

1983-01-01

Heat may be defined as that form of energy which spontaneously flows between two bodies, or two regions of a body, by virtue of a temperature difference. The second law of thermodynamics tells us that we cannot have heat flow from a low temperature to high temperature without doing work. Heat flows spontaneously from a high temperature to a low temperature region. Thermodynamics, which is concerned with equilibrium states, cannot tell us anything about the rate of heat flow in the presence of a finite temperature difference. It is to the discipline of heat transfer to which we must turn for this answer

Air-side performance evaluation of three types of heat exchangers in dry, wet and periodic frosting conditions

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ping [Zhejiang Vocational College of Commerce, Hangzhou, Binwen Road 470 (China); Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign 1206 West Green Street, Urbana, IL 61801 (United States); Hrnjak, P.S. [Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign 1206 West Green Street, Urbana, IL 61801 (United States)

2009-08-15

The performances of three types of heat exchangers that use the louver fin geometry: (1) parallel flow parallel fin with extruded flat tubes heat exchanger (PF{sup 2}), (2) parallel flow serpentine fin with extruded flat tubes heat exchanger (PFSF) and (3) round tube wave plate fin heat exchanger (RTPF) have been experimentally studied under dry, wet and frost conditions and results are presented. The parameters quantified include air-side pressure drop, water retention on the surface of the heat exchanger, capacity and overall heat transfer coefficient for air face velocity 0.9, 2 and 3 m/s, air humidity 70% and 80% and different orientations. The performances of three types of heat exchanger are compared and the results obtained are presented. The condensate drainage behavior of the air-side surface of these three heat exchanger types was studied using both the dip testing method and wind tunnel experiment. (author)

Effect of Thermophysical Properties on Coupled Heat and Mass Transfer in Porous Material during Forced Convective Drying

Directory of Open Access Journals (Sweden)

Wei Cai

2014-06-01

Full Text Available The convective drying kinetics of porous medium was investigated numerically. A mathematical model for forced convective drying was established to estimate the evolution of moisture content and temperature inside multilayered porous medium. The set of coupled partial differential equations with the specified boundary and initial conditions were solved numerically using a MATLAB code. An experimental setup of convective drying had been constructed and validated the theoretical model. The temperature and moisture content of the potato samples were dynamically measured and recorded during the drying process. Results indicate that thermal diffusion coefficient has significant positive impact on temperature distribution and mass diffusion coefficient might directly affect the moisture content distribution. Soret effect has a significant impact on heat flux and temperature distribution in the presence of large temperature gradient.

Prevention of spontaneous combustion in coal stockpiles : Experimental results in coal storage yard

NARCIS (Netherlands)

Fierro, V.; Miranda, J.L.; Romero, C.; Andrés, J.M.; Arriaga, A.; Schmal, D.; Visser, G.H.

1999-01-01

The spontaneous ignition of coal stockpiles is a serious economic and safety problem. This paper deals with oxidation and spontaneous combustion of coal piles laid in coal storage yard and the measures to avoid the heat losses produced. Investigations on self heating were carried out with five test

Drying of building lumber

Energy Technology Data Exchange (ETDEWEB)

Washimi, Hiroshi

1988-08-20

Dried lumber is classified into air dried and kiln-dried lumber. The water content of kiln-dried lumber is specified by the Japan Agricultural Standards. However, since building lumber varies in such factors as the location where it was growing, species and shape, the standards, though relaxed, are not being observed. In fact, lumbered products which are not ''Kiln-dried'' frequently bear ''kiln-dried lumber'' marks. In an attempt to correct the situation, the Forestry Agency has set up voluntary standards, but problems still remain. The conventional drying method consists of first subjecting the lumber to optimum drying, then letting bending and deformations to freely and fully appear, and follow this with corrective sawing to produce planks straight from end to end. Compared with air dried lumber in terms of moisture content, kiln-dried lumber remains much with same with minimal shrinkage and expansion. For oil-containing resin, such normal treatments as drying by heating, steaming and boiling seem to be quite effective. Kiln drying, which is becoming more and more important with changes in the circulation system, consists of the steaming-drying-heating method and the dehumidizing type drying method. The major factor which determines the drying cost is the number of days required for drying, which depends largely on the kind of lumber and moisture content. The Forestry Angency is promoting production of defoiled lumber. (2 figs, 2 tables)

Parity Differences in Heat Expression of Dairy Cows Synchronized with GnRH, CIDR and PGF2α during Dry Season in Zambia

Directory of Open Access Journals (Sweden)

E. S. Mwaanga*, K. Choongo, H. Simukoko and C. Chama1

2012-01-01

Full Text Available A study was conducted to investigate parity differences in heat expression of dairy cows heat-synchronized during the dry season when feed scarcity is common. Cyclic cows (n=65 aged 2 to 10 years with parity range of 0 to 7 were selected from small-holder dairy farms around Lusaka. Cows were divided into 3 groups of nulliparous, primiparous and pluriparous. Heat-was synchronized using gonadotrophin releasing hormone (GnRH and controlled intra-vaginal drug releasing device (CIDR. Heat detection was observed after CIDR withdraw. The study showed a significantly (P<0.05 lower number of primiparous cows (68% coming into heat compared to nulliparous (81.8% and pluriparous cows (83.3%. It was concluded that parity influences estrus expression rate in dairy cows following synchronization with GnRH, CIDR and PGF2α during the dry season in the sub-tropics.

A mathematical model for DRY-OUT

International Nuclear Information System (INIS)

Mariy, A.; Khattab, M.; Olama, H.

1989-01-01

In this study a model has been developed for describing the thermal surface conditions at dry out in a vertical channel with uniform heat flux. The use of droplet generation rate and vapor-droplet-wall heat transfer relations together with the dry and wet side energy equations lead to evaluation of the wall surface temperature and heat transfer distributions before and after dry out. Comparison with the previous theoretical and experimental results are presented. The steady state approach developed showed to be in good agreement with the experimental results

Effect of process parameters on energy performance of spray drying with exhaust air heat recovery for production of high value particles

International Nuclear Information System (INIS)

Julklang, Wittaya; Golman, Boris

2015-01-01

Highlights: • We study heat recovery from spray dryer using air-to-air heat exchanger. • We examine dryer energy performance using advanced mathematical model. • We use the response surface methodology to study the effect of process parameters. • Energy efficiency up to 43.3% is obtained at high flow rate of dilute slurry. • Energy saving up to 52.4% is obtained at high drying air temperature. - Abstract: Spray drying process has been widely used in various industries for many decades for production of numerous materials. This paper explores the energy performance of an industrial scale spray dryer equipped with an exhaust air heat recovery system for production of high value particles. Energy efficiency and energy saving were calculated using a comprehensive mathematical model of spray drying. The response surface methodology (RSM) was utilized to study the effect of process parameters on energy performance using a space-filling design. The meta model equations were formulated employing the well-fitted response surface equations with adjusted R 2 larger than 0.995. The energy efficiency as high as 43.3% was obtained at high flow rate of dilute slurry, while the highest energy saving of 52.4% was found by combination of positive effect of drying air temperature and negative effect of slurry mass flow rate. The utilization of efficient air-to-air heat exchanger leads to an increase in energy efficiency and energy savings. The detailed temperature and vapor concentration profiles obtained with the model are also valuable in determining final product quality when spray dryer is operated at energy efficient conditions

After-heat removing system in FBR type reactor

International Nuclear Information System (INIS)

Ohashi, Yukio.

1990-01-01

The after-heat removing system of the present invention removes the after heat generated in a reactor core without using dynamic equipments such as pumps or blowers. There are disposed a first heat exchanger for heating a heat medium by the heat in a reactor container and a second heat exchanger situated above the first heat exchanger for spontaneously air-cooling the heat medium. Recycling pipeways connect the first and the second heat exchangers to form a recycling path for the heat medium. Then, since the second heat exchanger for spontaneously air-cooling the heat medium is disposed above the first heat exchanger and they are connected by the recycling pipeways, the heat medium can be circulated spontaneously. Accordingly, dynamic equipments such as pumps or blowers are no more necessary. As a result, the after-heat removing system of the FBR type reactor of excellent safety and reliability can be obtained. (I.S.)

Development of Solar Biomass Drying System

Directory of Open Access Journals (Sweden)

Atnaw Samson Mekbib

2017-01-01

Full Text Available The purpose of this paper focuses on the experimental pre-treatment of biomass in agricultural site using solar energy as power source and contribution of common use and efficiency solar dryer system for consumer. The main purpose of this design for solar cabinet dryer is to dry biomass via direct and indirect heating. Direct heating is the simplest method to dry biomass by exposing the biomass under direct sunlight. The solar cabinet dryer traps solar heat to increase the temperature of the drying chamber. The biomass absorbs the heat and transforms the moisture content within the biomass into water vapour and then leaves the chamber via the exhaust air outlet. This problem however can be solved by adopting indirect solar drying system. High and controllable temperatures can be achieved as a fan is used to move the air through the solar collector. This project has successfully created a solar cabinet dryer that combines both direct and indirect solar drying systems and functions to dry biomass as well as crops effectively and efficiently with minimal maintenance. Hence, it is indeed a substitution for conventional dryers which are affordable to local farmers.

Definition of spontaneous reconnection

International Nuclear Information System (INIS)

Schindler, K.

1984-01-01

The author discusses his view of driven versus spontaneous. There is a close link between ''spontaneous'' and ''instability.'' One of the prominent examples for instability is the thermal convection instability. Just to remind you, if you heat a fluid layer from below, it takes a certain Rayleigh number to make it unstable. Beyond the onset point you find qualitatively new features. That is called ''spontaneous,'' and this is a bit more than semantics. It's a new qualitative property that appears and it is spontaneous although we have an energy flux through the system. It's a misconception, to call this ''driven'' pointing at the energy flux through it. Of course, the convection would not exist without this energy flux. But what makes it ''spontaneous'' is that without any particular external signal, a new qualitative feature appears. And this is what is called an ''instability'' and ''spontaneous.'' From these considerations the author got a little reassured of what distinction should be made in the field of the magnetosphere. If we have a smooth energy transport into the magnetosphere and suddenly we have this qualitatively new feature (change of B-topology) coming up; then, using this terminology we don't have a choice other than calling this spontaneous or unstable, if you like. If we ''tell'' the system where it should make its neutral line and where it should make its plasmoids, then, it is driven. And this provides a very clear-cut observational distinction. The author emphasizes the difference he sees is a qualitative difference, not only a quantitative one

Dimensionless model to determine spontaneous combustion danger zone in the longwall gob

Institute of Scientific and Technical Information of China (English)

ZHANG Xin-hai; DENG Jun; WEN Hu

2011-01-01

According to spontaneous combustion propensity,the longwall gob is divided into three zones,including heat dissipation zone,self-heating zone and the choking zone.Only in the self-heating zone can temperature of coal rise due to oxidation.Studying the distribution of the “Three Zones” in gob is important for predicting and preventing spontaneous combustion in coalmine.In normal mining operations,temperature of coal is roughly constant.The process of mass transfer in the gob is considered to be steady.Based on mass conservation,gas species conservation,darcy' s law,Ficks law of diffusion and coal oxidation 1-grade reaction rule,governing equation for air leakage intensity and species concentration are deduced.With critical value of coal spontaneous combustion and the size of longwall workface as basic dimension,a dimensionless steady coupled model of air flow diffusion and chemical reaction in loose coal of Fully Mechanized Top-Coal Caving Mining Workface (FMTCCMW) is setup.By solving the model numerically,regulation of three zones' distribution and spontaneous combustion in the gob can be obtained.The results can be easily popularized to prediction of spontaneous combustion in other coalmines' longwall gob.

Application of freeze-drying technology in manufacturing orally disintegrating films.

Science.gov (United States)

Liew, Kai Bin; Odeniyi, Michael Ayodele; Peh, Kok-Khiang

2016-01-01

Freeze drying technology has not been maximized and reported in manufacturing orally disintegrating films. The aim of this study was to explore the freeze drying technology in the formulation of sildenafil orally disintegrating films and compare the physical properties with heat-dried orally disintegrating film. Central composite design was used to investigate the effects of three factors, namely concentration of carbopol, wheat starch and polyethylene glycol 400 on the tensile strength and disintegration time of the film. Heat-dried films had higher tensile strength than films prepared using freeze-dried method. For folding endurance, freeze-dried films showed improved endurance than heat-dried films. Moreover, films prepared using freeze-dried methods were thicker and had faster disintegration time. Formulations with higher amount of carbopol and starch showed higher tensile strength and thickness whereas formulations with higher PEG 400 content showed better flexibility. Scanning electron microscopy showed that the freeze-dried films had more porous structure compared to the heat-dried film as a result of the release of water molecule from the frozen structure when it was subjected to freeze drying process. The sildenafil film was palatable. The dissolution profiles of freeze-dried and heat-dried films were similar to Viagra® with f2 of 51.04 and 65.98, respectively.

Dry eye syndrome

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/000426.htm Dry eye syndrome To use the sharing features on this page, ... second-hand smoke exposure Cold or allergy medicines Dry eye can also be caused by: Heat or ... Symptoms may include: Blurred vision Burning, itching, ...

Design of Tomato Drying System by Utilizing Brine Geothermal

Science.gov (United States)

Afuar, W.; Sibarani, B.; Abdurrahman, G.; Hendrarsakti, J.

2016-09-01

Cultivation of tomato plants in Indonesia has been started since 1961.Tomatoes generally will rot in three days if left on storage. Moreover, low quality tomatoes have cheaper price. After harvested, tomatoes need to be treated by drying process so it can last longer. Energy for drying tomatoes can be obtained by utilizing heat from geothermal brine. Purpose of this research is to design a tomato drying system by extracting heat of geothermal brine from separator with certain flow rate to heat up water by using a heat exchanger. Furthermore, this water will be used to heat up the surrounding air which is circulated by blower system to heat up the tomatoes chamber. Tomatoes drying process needs temperature range of 50-70°C to evaporate water content from 95.7% to 26%. After that treatment, the tomatoes are expected to have better durability. The objective of this study is to determine the quantity of hot brine which is needed for drying tomatoes and to design a drying system so that tomatoes can last longer.

Invited review: heat stress effects during late gestation on dry cows and their calves.

Science.gov (United States)

Tao, S; Dahl, G E

2013-07-01

In dairy cattle, late gestation is a critical period for fetal growth and physiological transition into the next lactation. Environmental factors, such as temperature and light, exert dramatic effects on the production, health, and well-being of animals during this period and after parturition. The aim of this review was to introduce effects of heat stress during late gestation on dairy cattle, and discuss the biological mechanisms that underlie the observed production and health responses in the dam and her fetus. Relative to cooled cows, cows that are heat stressed during late gestation have impaired mammary growth before parturition and decreased milk production in the subsequent lactation. In response to higher milk yield, cows cooled prepartum undergo a series of homeorhetic adaptations in early lactation to meet higher demand for milk synthesis compared with heat-stressed cows, but no direct effect of environmental heat stress on metabolism exists during the dry period. Prepartum cooling improves immune status of transition cows and evidence suggests that altered prolactin signaling in immune cells mediates the effects of heat stress on immune function. Late-gestation heat stress compromises placental development, which results in fetal hypoxia, malnutrition, and eventually fetal growth retardation. Maternal heat stress may also have carryover effects on the postnatal growth of offspring, but direct evidence is still lacking. Emerging evidence suggests that offspring from prepartum heat-stressed cows have compromised passive immunity and impaired cell-mediated immune function compared with those from cooled cows. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effectiveness of a heat exchanger in a heat pump clothes dryer

Science.gov (United States)

Nasution, A. H.; Sembiring, P. G.; Ambarita, H.

2018-02-01

This paper deals with study on a heat pump clothes dryer coupled with a heat exchanger. The objective is to explore the effects of the heat exchanger on the performance of the heat pump dryer. The heat pump dryer consists of a vapor compression cycle and integrated with a drying room with volume 1 m3. The power of compressor is 800 Watt and the refrigerant of the cycle is R22. The heat exchanger is a flat plate type with dimensions of 400 mm × 400 mm × 400 mm. The results show the present of the heat exchanger increase the performance of the heat pump dryer. In the present experiment the COP, TP and SMER increase 15.11%, 4.81% and 58.62%, respectively. This is because the heat exchanger provides a better drying condition in the drying room with higher temperature and lower relative humidity in comparison with heat pump dryer without heat exchanger. The effectiveness of the heat exchanger is also high, it is above 50%. It is suggested to install a heat exchanger in a heat pump dryer.

HEAT INSULATING LIME DRY MORTARS FOR FINISHING OF WALLS MADE OF FOAM CONCRETE

Directory of Open Access Journals (Sweden)

Loganina Valentina Ivanovna

2016-05-01

Full Text Available Different aerated mortars are used for pargeting of walls made of aerated concrete. Though the regulatory documents don’t specify the dependence of plaster density from the density grade of gas-concrete blocks. In case of facing of gas-concrete blocks with the grade D500 using plaster mortars with the density 1400…1600 km/m3 there occurs a dismatch in the values of thermal insulation and vapor permeability of the plaster and base. The authors suggest using dry mortars for finishing of gas-concrete block of the grades D500 и D600, which allow obtaining facing thermal insulating coatings. The efficiency of using four different high-porous additives in the lime dry mortar was compared. They were: hollow glass microspheres, aluminosilicate ash microspheres, expanded vermiculite sand, expanded pearlitic sand. The high efficiency of hollow glass microspheres in heat insulating finishing mortars compared to other fillers is proved.

Studies on the radiation drying method for grain, 2: A good drying method of paddy rice from the viewpoint of the drying rate and the crack generation of rice

International Nuclear Information System (INIS)

Horibe, K.; Nakagawa, K.; Tohjo, T.

1990-01-01

A drying rate of paddy rice in a solar heat drying plant was studied. Solar-heated air at the upper part of a plastic house was blasted to the surface of the layer of paddy rice which was piled on the floor of the house. The drying rate increased with higher wind velocity, but it was found that the velocity was limited to 6m/s by the crack generation of the paddy rice. The effects of the layer thickness, the number of layer agitations and the heat supplied on the drying rate at a given wind velocity (6m/s) were expressed with a multiple regression equation. Then, the equation positively proposed appropriate conditions for effective operation of the plant in fine days

Development of an integrated MOX-scrap recycling flow-sheet by dry and wet routes using microwave heating techniques

Energy Technology Data Exchange (ETDEWEB)

Mallik, G K; Malav, R K; Karande, A P; Bhargava, V K; Kamath, H S [Advanced Fuel Fabrication Facility, Bhabha Atomic Research Centre, Tarapur (India)

1999-01-01

A simple, short and efficient scrap, recycling flow-sheet, which is exclusively based on microwave heating techniques and, includes both dry and wet routes, for (U,Pu)O{sub 2} fuel scrap recycling has been developed and evaluated. (author) 6 refs., 1 tab.

Dry sliding wear behaviour of heat treated iron based powder metallurgy steels with 0.3% Graphite + 2% Ni additions

International Nuclear Information System (INIS)

Tekeli, S.; Gueral, A.

2007-01-01

To determine the effect of various heat treatments on the microstructure and dry sliding wear behaviour of iron based powder metallurgy (PM) steels, atomized iron powder was mixed with 0.3% graphite + 2% Ni. The mixed powders were cold pressed at 700 MPa and sintered at 1200 deg. C for 30 min under pure Ar gas atmosphere. One of the sintered specimens was quenched from 890 deg. C and then tempered at 200 deg. C for 1 h. The other sintered specimens were annealed at different intercritical heat treatment temperatures of 728 and 790 deg. C and water quenched. Through this intercritical annealing heat treatment, the specimens with various ferrite + martensite volume fractions were produced. Wear tests were carried out on the quenched + tempered and intercritically annealed specimens under dry sliding conditions using a pin-on-disk type machine at constant load and speed and the results were compared in terms of microstructure, hardness and wear strength. It was seen that hardness and wear strength in intercritically annealed specimens were higher than that of quenched + tempered specimen

Dry sliding wear behavior of heat treated hybrid metal matrix composite using Taguchi techniques

International Nuclear Information System (INIS)

Kiran, T.S.; Prasanna Kumar, M.; Basavarajappa, S.; Viswanatha, B.M.

2014-01-01

Highlights: • ZA-27 alloy is used as matrix material and reinforced with SiC and Gr particles. • Heat treatment was carried out for all specimen. • Dry sliding wear test was done on pin-on-disc apparatus by Taguchi technique. • ZA-27/9SiC–3Gr showed superior wear resistance over the base alloy. • Ceramic mixed mechanical layer on contact surface of composite was formed. - Abstract: Dry sliding wear behavior of zinc based alloy and composite reinforced with SiCp (9 wt%) and Gr (3 wt%) fabricated by stir casting method was investigated. Heat treatment (HT) and aging of the specimen were carried out, followed by water quenching. Wear behavior was evaluated using pin on disc apparatus. Taguchi technique was used to estimate the parameters affecting the wear significantly. The effect of HT was that it reduced the microcracks, residual stresses and improved the distribution of microconstituents. The influence of various parameters like applied load, sliding speed and sliding distance on wear behavior was investigated by means and analysis of variance (ANOVA). Further, correlation between the parameters was determined by multiple linear regression equation for each response. It was observed that the applied load significantly influenced the wear volume loss (WVL), followed by sliding speed implying that increase in either applied load or sliding speed increases the WVL. Whereas for composites, sliding distance showed a negative influence on wear indicating that increase in sliding distance reduces WVL due to the presence of reinforcements. The wear mechanism of the worn out specimen was analyzed using scanning electron microscopy. The analysis shows that the formation and retention of ceramic mixed mechanical layer (CMML) plays a major role in the dry sliding wear resistance

A dry-spot model for the prediction of critical heat flux in water boiling in bubbly flow regime

International Nuclear Information System (INIS)

Ha, Sang Jun; No, Hee Cheon

1997-01-01

This paper presents a prediction of critical heat flux (CHF) in bubbly flow regime using dry-spot model proposed recently by authors for pool and flow boiling CHF and existing correlations for forced convective heat transfer coefficient, active site density and bubble departure diameter in nucleate boiling region. Without any empirical constants always present in earlier models, comparisons of the model predictions with experimental data for upward flow of water in vertical, uniformly-heated round tubes are performed and show a good agreement. The parametric trends of CHF have been explored with respect to variation in pressure, tube diameter and length, mass flux and inlet subcooling

Drying of α-amylase by spray drying and freeze-drying - a comparative study

Directory of Open Access Journals (Sweden)

S. S. de Jesus

2014-09-01

Full Text Available This study is aimed at comparing two traditional methods of drying of enzymes and at verifying the efficiency of each one and their advantages and disadvantages. The experiments were performed with a laboratory spray dryer and freeze-dryer using α-amylase as the model enzyme. An experimental design in star revealed that spray drying is mainly influenced by the inlet air temperature and feed flow rate, which were considered to be the main factors influencing the enzymatic activity and water activity; the long period of material exposure to high temperatures causes a partial activity loss. In the experiments of freeze drying, three methods of freezing were used (freezer, acetone and dry ice, and liquid nitrogen and samples subsequently freeze-dried for times ranging between 0-24 hours. The product obtained from the two techniques showed high enzymatic activity and low water activity. For the drying of heat-resistant enzymes, in which the product to be obtained does not have high added value, spray drying may be more economically viable because, in the freeze drying process, the process time can be considered as a limiting factor when choosing a technique.

Dry/wet performance of a plate-fin air-cooled heat exchanger with continuous corrugated fins

International Nuclear Information System (INIS)

Hauser, S.G.; Kreid, D.K.; Johnson, B.M.

1981-01-01

The performance and operating characteristics of a plate-fin heat exchanger in dry/wet or deluge operations was experimentally determined. Development of the deluge heat/mass transfer model continued. The experiments were conducted in a specially-designed wind tunnel at the PNL. Air that was first heated and humidified to specified conditions was circulated at a controlled rate through a 2 ft x 6 ft heat exchanger module. The heat exchanger used in the tests was a wavy surface, plate fin on tube configuration. Hot water was circulated through the tubes at high flow rates to maintain an essentially isothermal condition on the tube side. Deionized water sprayed on the top of the vertically oriented plate fins was collected at the bottom of the core and recirculated. Instrumentation was provided for measurement of flow rates and thermodynamic conditions in the air, in the core circulation water, and in the deluge water. Measurements of the air side pressure drop and heat rejection rate were made as a function of air flow rate, air inlet temperature and humidity, deluge water flow rate, and the core inclination from the vertical. An overall heat transfer coefficient and an effective deluge film convective coefficient was determined. The deluge model, for predicting heat transfer from a wet finned heat exchanger was further developed and refined, and a major extension of the model was formulated that permits simultaneous calculation of both the heat transfer and evaporation rates from the wetted surface. The experiments showed an increase in the heat rejection rate due to wetting, accompanied by a proportional increase in the air side pressure drop. For operation at the same air side pressure drop, the enhancement ratio Q/sub w//Q/sub d/ varied between 2 and 5 for the conditions tested. Thus, the potential enhancement of heat transfer due to wetting can be substantial

Design Of Dry Cask Storage For Serpong Multipurpose Reactor Spent Nuclear Fuel

Directory of Open Access Journals (Sweden)

Dyah Sulistyani Rahayu

2018-03-01

Full Text Available DESIGN OF DRY CASK STORAGE FOR SERPONG MULTI PURPOSE REACTOR SPENT NUCLEAR FUEL. The spent nuclear fuel (SNF from Serpong Multipurpose Reactor, after 100 days storing in the reactor pond, is transferred to water pool interim storage for spent fuel (ISFSF. At present there are a remaining of 245 elements of SNF on the ISSF,198 element of which have been re-exported to the USA. The dry-cask storage allows the SNF, which has already been cooled in the ISSF, to lower its radiation exposure and heat decayat a very low level. Design of the dry cask storage for SNF has been done. Dual purpose of unventilated vertical dry cask was selected among other choices of metal cask, horizontal concrete modules, and modular vaults by taking into account of technical and economical advantages. The designed structure of cask consists of SNF rack canister, inner steel liner, concrete shielding of cask, and outer steel liner. To avoid bimetallic corrosion, the construction material for canister and inner steel liner follows the same material construction of fuel cladding, i.e. the alloy of AlMg2. The construction material of outer steel liner is copper to facilitate the heat transfer from the cask to the atmosphere. The total decay heat is transferred from SNF elements bundle to the atmosphere by a serial of heat transfer resistance for canister wall, inner steel liner, concrete shielding, and outer steel liner respectedly. The rack canister optimum capacity of 34 fuel elements was designed by geometric similarity method basedon SNF position arrangement of 7 x 6 triangular pitch array of fuel elements for prohibiting criticality by spontaneous neutron. The SNF elements are stored vertically on the rack canister.  The thickness of concrete wall shielding was calculated by trial and error to give air temperature of 30 oC and radiation dose on the wall surface of outer liner of 200 mrem/h. The SNF elements bundles originate from the existing racks of wet storage, i

Numerical simulation of heat transfer process in solar enhanced natural draft dry cooling tower with radiation model

International Nuclear Information System (INIS)

Wang, Qiuhuan; Zhu, Jialing; Lu, Xinli

2017-01-01

Graphical abstract: A 3-D numerical model integrated with a discrete ordinate (DO) solar radiation model (considering solar radiation effect in the room of solar collector) was developed to investigate the influence of solar radiation intensity and ambient pressure on the efficiency and thermal characteristics of the SENDDCT. Our study shows that introducing such a radiation model can more accurately simulate the heat transfer process in the SENDDCT. Calculation results indicate that previous simulations overestimated solar energy obtained by the solar collector and underestimated the heat loss. The cooling performance is improved when the solar radiation intensity or ambient pressure is high. Air temperature and velocity increase with the increase of solar radiation intensity. But ambient pressure has inverse effects on the changes of air temperature and velocity. Under a condition that the solar load increases but the ambient pressure decreases, the increased rate of heat transferred in the heat exchanger is not obvious. Thus the performance of the SENDDCT not only depends on the solar radiation intensity but also depends on the ambient pressure. - Highlights: • A radiation model has been introduced to accurately simulate heat transfer process. • Heat transfer rate would be overestimated if the radiation model was not introduced. • The heat transfer rate is approximately proportional to solar radiation intensity. • The higher the solar radiation or ambient pressure, the better SENDDCT performance. - Abstract: Solar enhanced natural draft dry cooling tower (SENDDCT) is more efficient than natural draft dry cooling tower by utilizing solar radiation in arid region. A three-dimensional numerical model considering solar radiation effect was developed to investigate the influence of solar radiation intensity and ambient pressure on the efficiency and thermal characteristics of SENDDCT. The numerical simulation outcomes reveal that a model with consideration of

Advanced exergoeconomic analysis of a gas engine heat pump (GEHP) for food drying processes

International Nuclear Information System (INIS)

Gungor, Aysegul; Tsatsaronis, George; Gunerhan, Huseyin; Hepbasli, Arif

2015-01-01

Highlights: • Comparison between conventional and advanced exergoconomic analyses for food drying. • 74% of the total energy destruction can be avoided. • The condenser has the highest improvement potential. • Inefficiencies and options for improvement are identified for each component. - Abstract: Exergetic and exergoeconomic analyses are often used to evaluate the performance of energy systems from the thermodynamic and economic points of view. While a conventional exergetic analysis can be used to recognize the sources of inefficiencies, the so-called advanced exergy-based analysis is convenient for identifying the real potential for thermodynamic improvements and the system component interactions by splitting the exergy destruction and the total operating cost within each component into endogenous/exogenous and unavoidable/avoidable parts. In this study for the first time an advanced exergoeconomic analysis is applied to a gas-engine-driven heat pump (GEHP) drying system used in food drying for evaluating its performance along with each component. The advanced exergoeconomic analysis shows that the unavoidable part of the exergy destruction cost rate within the components of the system is lower than the avoidable part. The most important components based on the total avoidable costs are drying ducts, the condenser and the expansion valve. The inefficiencies within the condenser could particularly be improved by structural improvements of the whole system and the remaining system components. Finally, it can be concluded that the internal design changes play a more essential role in determining the cost of each component

Physicochemical Characterization of a Heat Treated Calcium Alginate Dry Film Prepared with Chicken Stock.

Science.gov (United States)

Báez, Germán D; Piccirilli, Gisela N; Ballerini, Griselda A; Frattini, Agustín; Busti, Pablo A; Verdini, Roxana A; Delorenzi, Néstor J

2017-04-01

Solid sodium alginate was dissolved into chicken stock in order to give a final alginate concentration of 0.9 percent (w/v). Calcium ions present in chicken stock were enough to induce ionic gelation. After drying, Fourier transform infrared spectroscopy, thickness and mechanical properties of films obtained were determined. Calcium alginate-chicken stock films were heated at 130 °C for different times between 0 and 15 min. Mechanical and optical studies, differential scanning calorimetry, visual aspect and scanning electron microscopy were carried out to describe physicochemical properties of heat treated films. Heating developed a maroon ochre color and increased the brittleness (crispness) of the films related to the intensity of the treatment. Differential scanning thermometry and study on appearance of the films suggested that Maillard reactions may be responsible for the observed changes. Maillard reactions mainly occurred between reducing sugar monomers and free amino groups of gelatin peptides present in the chicken stock, and between alginate and gelatin peptides to a lesser extent. In addition, the plasticizing effect of fat added with chicken stock was also studied. These studies suggest a potential use of heat treated chicken stock films as a substitute of roasted chicken skin. © 2017 Institute of Food Technologists®.

Exergy Steam Drying and Energy Integration

Energy Technology Data Exchange (ETDEWEB)

Verma, Prem; Muenter, Claes (Exergy Engineering and Consulting, SE-417 55 Goeteborg (Sweden)). e-mail: verma@exergyse.com

2008-10-15

Exergy Steam Drying technology has existed for past 28 years and many new applications have been developed during this period. But during past few years the real benefits have been exploited in connection with bio-fuel production and energy integration. The steam dryer consists of a closed loop system, where the product is conveyed by superheated and pressurised carrier steam. The carrier steam is generated by the water vapours from the product being dried, and is indirectly superheated by another higher temperature energy source such as steam, flue gas, thermal oil etc. Besides the superior heat transfer advantages of using pressurised steam as a drying medium, the energy recovery is efficient and simple as the recovered energy (80-90%) is available in the form of steam. In some applications the product quality is significantly improved. Examples presented in this paper: Bio-Combine for pellets production: Through integration of the Exergy Steam Dryer for wood with a combined heat and power (CHP) plant, together with HP steam turbine, the excess carrier steam can be utilised for district heating and/or electrical power production in a condensing turbine. Bio-ethanol production: Both for first and second generation of ethanol can the Exergy process be integrated for treatment of raw material and by-products. Exergy Steam Dryer can dry the distillers dark grains and solubles (DDGS), wood, bagasse and lignin. Bio-diesel production: Oil containing seeds and fruits can be treated in order to improve both the quality of oil and animal feed protein, thus minimizing further oil processing costs and increasing the sales revenues. Sewage sludge as bio-mass: Municipal sewage sludge can be considered as a renewable bio-fuel. By drying and incineration, the combustion heat value of the sludge is sufficient for the drying process, generation of electrical energy and production of district heat. Keywords; Exergy, bio-fuel, bio-mass, pellets, bio-ethanol, biodiesel, bio

Spontaneous ignition characteristics of coal in a large-scale furnace: An experimental and numerical investigation

International Nuclear Information System (INIS)

Wen, Hu; Yu, Zhijin; Deng, Jun; Zhai, Xiaowei

2017-01-01

Highlights: • Three coal spontaneous combustion coupled models based on various flow equations were constructed and compared. • The airflow behavior in loose coal should be defined as a Brinkman flow. • The self-heating of coal in a large-scale reactor was numerically reappeared. • The effect of heat dissipated conditions on temperature profiles of broken coal was presented. - Abstract: A comprehensive understanding of the spontaneous combustion characteristics of coal in various surroundings is necessary for developing reliable test platform and predictive models. In this study, the characteristics of oxidation and self-heating combining various gas flow equations in loose coal were investigated separately and used to simulate the experimental procedure of spontaneous combustion. The main focus was to investigate the effect of thermal boundary on temperature profiles as well as spontaneous combustion period. The results showed that the numerical approach was validated by comparison with the test data. Furthermore, the model based upon Brinkman equation showed a higher accuracy, which indicated that airflow behavior influences the balances of coal oxidation and heat dissipation, thus impacts the temperature profiles of loose coal. The areas of high temperature zones would be evidently expanded and the spontaneous ignition time would be significantly accelerated if the thermal exchange between the coal and its surroundings decreased. Our results, especially for the field of engineering, have substantial effects for grasping and controlling coal spontaneous combustion disaster.

A dry-spot model for the prediction of critical heat flux in water boiling in bubbly flow regime

Energy Technology Data Exchange (ETDEWEB)

Ha, Sang Jun; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1998-12-31

This paper presents a prediction of critical heat flux (CHF) in bubbly flow regime using dry-spot model proposed recently by authors for pool and flow boiling CHF and existing correlations for forced convective heat transfer coefficient, active site density and bubble departure diameter in nucleate boiling region. Without any empirical constants always present in earlier models, comparisons of the model predictions with experimental data for upward flow of water in vertical, uniformly-heated round tubes are performed and show a good agreement. The parametric trends of CHF have been explored with respect to variations in pressure, tube diameter and length, mass flux and inlet subcooling. 16 refs., 6 figs., 1 tab. (Author)

A dry-spot model for the prediction of critical heat flux in water boiling in bubbly flow regime

Energy Technology Data Exchange (ETDEWEB)

Ha, Sang Jun; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1997-12-31

This paper presents a prediction of critical heat flux (CHF) in bubbly flow regime using dry-spot model proposed recently by authors for pool and flow boiling CHF and existing correlations for forced convective heat transfer coefficient, active site density and bubble departure diameter in nucleate boiling region. Without any empirical constants always present in earlier models, comparisons of the model predictions with experimental data for upward flow of water in vertical, uniformly-heated round tubes are performed and show a good agreement. The parametric trends of CHF have been explored with respect to variations in pressure, tube diameter and length, mass flux and inlet subcooling. 16 refs., 6 figs., 1 tab. (Author)

Method for drying of biomass. Saett att torka biomassa

Energy Technology Data Exchange (ETDEWEB)

Eriksson, S

1987-06-01

Peat or biomass is dried in at least two steps. In the first step the material is dried by flue gases in a heat exchanger, the steam pressure being higher than in the subsequent drying step. The steam generated is separated from the solid phase and used for heating the second step.

Macroscopic modeling for heat and water vapor transfer in dry snow by homogenization.

Science.gov (United States)

Calonne, Neige; Geindreau, Christian; Flin, Frédéric

2014-11-26

Dry snow metamorphism, involved in several topics related to cryospheric sciences, is mainly linked to heat and water vapor transfers through snow including sublimation and deposition at the ice-pore interface. In this paper, the macroscopic equivalent modeling of heat and water vapor transfers through a snow layer was derived from the physics at the pore scale using the homogenization of multiple scale expansions. The microscopic phenomena under consideration are heat conduction, vapor diffusion, sublimation, and deposition. The obtained macroscopic equivalent model is described by two coupled transient diffusion equations including a source term arising from phase change at the pore scale. By dimensional analysis, it was shown that the influence of such source terms on the overall transfers can generally not be neglected, except typically under small temperature gradients. The precision and the robustness of the proposed macroscopic modeling were illustrated through 2D numerical simulations. Finally, the effective vapor diffusion tensor arising in the macroscopic modeling was computed on 3D images of snow. The self-consistent formula offers a good estimate of the effective diffusion coefficient with respect to the snow density, within an average relative error of 10%. Our results confirm recent work that the effective vapor diffusion is not enhanced in snow.

Apparatus for drying sugar cubes

NARCIS (Netherlands)

Derckx, H.A.J.; Torringa, H.M.

1999-01-01

Device for drying sugar cubes containing a heating apparatus for heating and dehumidifying the sugar cubes, a conditioning apparatus for cooling off and possibly further dehumidifying the sugar cubes and a conveying apparatus for conveying the sugar cubes through the heating apparatus and the

Drying hardwood lumber

Energy Technology Data Exchange (ETDEWEB)

Chow, A T

1988-11-14

Dried lumber is a high-value-added product, especially when it is of high quality. Lumber damaged during the drying operation can represent substantial lost revenue. It has been demonstrated that dehumidification kilns can improve lumber quality, and reduce energy consumption over conventional drying methods. A summary of the literature on drying hardwood lumber, particularly using heat pump dehumidification, has been prepared to allow the information to be readily accessible to Ontario Hydro personnel who work with customers in the lumber industry. For that purpose, this summary has been prepared from the perspective of the customer, a dry kiln operator. Included are brief descriptions of drying schedules, precautions needed to minimize drying defects in the lumber, and rules-of-thumb for selecting and estimating the capital cost of the drying equipment. A selection of drying schedules and moisture contents of green lumber, a glossary of lumber defects and brief descriptions of the possible preventive measures are also included. 10 refs., 8 figs., 4 tabs.

Steam atmosphere drying concepts using steam exhaust recompression

Energy Technology Data Exchange (ETDEWEB)

DiBella, F.A. (TECOGEN, Inc., Waltham, MA (United States))

1992-08-01

In the US industrial drying accounts for approximately 1.5 quads of energy use per year. Annual industrial dryer expenditures are estimated to be in the $500 million range. Industrial drying is a significant energy and monetary expense. For the thermal drying processes in which water is removed via evaporation from the feedstock, attempts have been made to reduce the consumption of energy using exhaust waste heat recovery techniques, improved dryer designs, or even the deployment of advanced mechanical dewatering techniques. Despite these efforts, it is obvious that a large amount of thermal energy is often still lost if the latent heat of evaporation from the evaporated water cannot be recovered and/or in some way be utilized as direct heat input into the dryer. Tecogen Inc. is conducting research and development on an industrial drying concept. That utilizes a directly or indirectly superheated steam cycle atmosphere with exhaust steam recompression to recover the latent heat in the exhaust that would otherwise be lost. This approach has the potential to save 55 percent of the energy required by a conventional air dryer. Other advantages to the industrial dryer user include: A 35-percent reduction in the yearly cost per kg[sub evap] to dry wet feedstock, Reduced airborne emissions, Reduced dry dust fire/explosion risks, Hot product not exposed to oxygen thus, the product quality is enhanced, Constant rate drying in steam atmosphere, Reduced dryer size and cost, Reduced dryer heat losses due to lower dryer inlet temperatures. Tecogen has projected that the steam atmosphere drying system is most suitable as a replacement technology for state-of-the-art spray, flash, and fluidized bed drying systems. Such systems are utilized in the food and kindred products; rubber products; chemical and allied products; stone, clay, and glass; textiles; and pulp and paper industrial sectors.

Steam atmosphere drying concepts using steam exhaust recompression

Energy Technology Data Exchange (ETDEWEB)

DiBella, F.A. [TECOGEN, Inc., Waltham, MA (United States)

1992-08-01

In the US industrial drying accounts for approximately 1.5 quads of energy use per year. Annual industrial dryer expenditures are estimated to be in the $500 million range. Industrial drying is a significant energy and monetary expense. For the thermal drying processes in which water is removed via evaporation from the feedstock, attempts have been made to reduce the consumption of energy using exhaust waste heat recovery techniques, improved dryer designs, or even the deployment of advanced mechanical dewatering techniques. Despite these efforts, it is obvious that a large amount of thermal energy is often still lost if the latent heat of evaporation from the evaporated water cannot be recovered and/or in some way be utilized as direct heat input into the dryer. Tecogen Inc. is conducting research and development on an industrial drying concept. That utilizes a directly or indirectly superheated steam cycle atmosphere with exhaust steam recompression to recover the latent heat in the exhaust that would otherwise be lost. This approach has the potential to save 55 percent of the energy required by a conventional air dryer. Other advantages to the industrial dryer user include: A 35-percent reduction in the yearly cost per kg{sub evap} to dry wet feedstock, Reduced airborne emissions, Reduced dry dust fire/explosion risks, Hot product not exposed to oxygen thus, the product quality is enhanced, Constant rate drying in steam atmosphere, Reduced dryer size and cost, Reduced dryer heat losses due to lower dryer inlet temperatures. Tecogen has projected that the steam atmosphere drying system is most suitable as a replacement technology for state-of-the-art spray, flash, and fluidized bed drying systems. Such systems are utilized in the food and kindred products; rubber products; chemical and allied products; stone, clay, and glass; textiles; and pulp and paper industrial sectors.

Technical research on sludge drying by solar energy and heat pump%太阳能热泵污泥干燥技术

Institute of Scientific and Technical Information of China (English)

饶宾期; 曹黎

2012-01-01

In order to solve the problems of sludge drying, the working principle and system structure of sludge drying-system by solar energy and heat pump were introduced firstly, and then the main equipment.of this system was calculated and designed, the system performance was analyzed comprehensively through experiment. Finally the energy efficiency and economy of solar energy heat pump drying-system were compared with that of the other drying system. The results showed that this system was energy-saving, eco-friendly and economy. Equipped with solar thermal collector, the system can save energy about 10% in average. The research can provide a reference for engineering application of sludge drying by solar energy and heat pump.%为解决当前污泥干燥存在的问题,该文研究利用太阳能热泵对污泥进行干燥,阐述了太阳能热泵污泥干燥系统的结构与工作原理,对系统的主要设备进行了计算设计并进行试验及性能分析,最后对太阳能热泵干燥与其他几种典型干燥方式的能耗及经济性做了比较.该系统具有节能、环保、经济等优点,配备太阳能系统平均可节省电量10％左右.该研究可为太阳能热泵干燥污泥的工程应用提供参考.

Heat transfer enhancement in a natural draft dry cooling tower under crosswind operation with heterogeneous water distribution

Energy Technology Data Exchange (ETDEWEB)

Goodarzi, Mohsen; Amooie, Hossein [Bu-Ali Sina Univ., Hamedan (Iran, Islamic Republic of). Dept. of Mechanical Engineering

2016-04-15

Crosswind significantly decreases cooling efficiency of a natural draft dry cooling tower. The possibility of improving cooling efficiency with heterogeneous water distribution within the cooling tower radiators under crosswind condition is analysed. A CFD approach was used to model the flow field and heat transfer phenomena within the cooling tower and airflow surrounding the cooling tower. A mathematical model was developed from various CFD results. Having used a trained Genetic Algorithm with the result of mathematical model, the best water distribution was found among the others. Remodeling the best water distribution with the CFD approach showed that the highest enhancement of the heat transfer compared to the usual uniform water distribution.

Heat transfer enhancement in a natural draft dry cooling tower under crosswind operation with heterogeneous water distribution

International Nuclear Information System (INIS)

Goodarzi, Mohsen; Amooie, Hossein

2016-01-01

Crosswind significantly decreases cooling efficiency of a natural draft dry cooling tower. The possibility of improving cooling efficiency with heterogeneous water distribution within the cooling tower radiators under crosswind condition is analysed. A CFD approach was used to model the flow field and heat transfer phenomena within the cooling tower and airflow surrounding the cooling tower. A mathematical model was developed from various CFD results. Having used a trained Genetic Algorithm with the result of mathematical model, the best water distribution was found among the others. Remodeling the best water distribution with the CFD approach showed that the highest enhancement of the heat transfer compared to the usual uniform water distribution.

Geothermal rice drying unit in Kotchany, Macedonia

International Nuclear Information System (INIS)

Popovski, K.; Dimitrov, K.; Andrejevski, B.; Popovska, S.

1992-01-01

A geothermal field in Kotchany (Macedonia) has very advantageous characteristics for direct application purposes. Low content of minerals, moderate temperature (78C) and substantial available geothermal water flow (up to 300 1/s) enabled the establishment of a district heating scheme comprising mainly agricultural and industrial uses. A rice drying unit of 10 t/h capacity was installed 8 years ago, using the geothermal water as the primary heat source. A temperature drop of 75/50C enables the adaptation of conventional drying technology, already proven in practice in the surrounding rice growing region. Water to air heat exchanger and all necessary equipment and materials are of local production, made of copper and carbon steel. The use of such drying units is strongly recommended for the concrete district heating scheme because it offers a very simple geothermal application and enables improvement in the annual heating load factor without high investments in geothermal water distribution lines

Electron-beam mediated dry distillation of lignin

International Nuclear Information System (INIS)

Chulkov, V.N.; Bludenko, A.V.; Ponomarev, A.V.

2007-01-01

Radiation heating was studied for its application in dry distillation of lignin under high absorbed-dose irradiation with no supplementary heating device used. Commercial preparation Polyphepan containing lignin (90 wt.%) and cellulose (10 wt.%), dried at 102 deg C, was used. The test samples were exposed to 8 MeV electron beams on U-003 linear accelerator under atmospheric pressure, with dose rates of 3.6 and 4.8 kGy/s. It is demonstrated that an increased yield of liquid products of dry lignin distillation is observed under conditions studied with a two-fold decrease in energy consumption due to more favorable heating conditions and intensification of free-radical reactions [ru

Changes in antibiotic sensitivity and cell surface hydrophobicity in Escherichia coli injured by heating, freezing, drying or gamma radiation

International Nuclear Information System (INIS)

Mackey, B.M.

1983-01-01

Escherichia coli cells exposed to mild heating, freezing and thawing, drying or γ-radiation were sensitised to hydrophobic antibiotics and sodium deoxycholate but not to small hydrophilic antibiotics. These stress treatments also caused increases in cell surface hydrophobicity broadly reflecting the degree of sensitivity to hydrophobic antibiotics. (Auth.)

Community Geothermal Technology Program: Experimental lumber drying kiln. Final report

Energy Technology Data Exchange (ETDEWEB)

Leaman, D.; Irwin, B.

1989-10-01

Goals were to demonstrate feasibility of using the geothermal waste effluent from the HGP-A well as a heat source for a kiln operation to dry hardwoods, develop drying schedules, and develop automatic systems to monitor/control the geothermally heated lumber dry kiln systems. The feasibility was demonstrated. Lumber was dried in periods of 2 to 6 weeks in the kiln, compared to 18 months air drying and 6--8 weeks using a dehumidified chamber. Larger, plate-type heat exchangers between the primary fluid and water circulation systems may enable the kiln to reach the planned temperatures (180--185 F). However, the King Koa partnership cannot any longer pursue the concept of geothermal lumber kilns.

Hydrophobic Light-to-Heat Conversion Membranes with Self-Healing Ability for Interfacial Solar Heating

KAUST Repository

Zhang, Lianbin

2015-07-01

Self-healing hydrophobic light-to-heat conversion membranes for interfacial solar heating are fabricated by deposition of light-to-heat conversion material of polypyrrole onto porous stainless steel mesh, followed by hydrophobic fluoroalkylsilane modification. The mesh-based membranes spontaneously stay at the water–air interface, collect and convert solar light into heat, and locally heat only the water surface for an enhanced evaporation.

Hydrophobic Light-to-Heat Conversion Membranes with Self-Healing Ability for Interfacial Solar Heating

KAUST Repository

Zhang, Lianbin; Tang, Bo; Wu, Jinbo; Li, Renyuan; Wang, Peng

2015-01-01

Self-healing hydrophobic light-to-heat conversion membranes for interfacial solar heating are fabricated by deposition of light-to-heat conversion material of polypyrrole onto porous stainless steel mesh, followed by hydrophobic fluoroalkylsilane modification. The mesh-based membranes spontaneously stay at the water–air interface, collect and convert solar light into heat, and locally heat only the water surface for an enhanced evaporation.

Aroma characterisation and retention after heat treatment and drying of fruits using extraction and GC-MS analysis

OpenAIRE

Ráice, Rui

2015-01-01

This study concerns the identification and characterisation of volatile components of fruits, and evaluation of the effect of heat treatment and drying on retention or loss of volatiles of fruits. The investigation included developing a procedure to extract volatile components from the fruit matrix, a purification step, separation, identification and quantification. Initial experiments with Vangueria infausta L. showed that some components, especially sugars, degrade during ...

Unusual specific heat of almost dry L-cysteine and L-cystine amino acids.

Science.gov (United States)

Ishikawa, M S; Lima, T A; Ferreira, F F; Martinho, H S

2015-03-01

A detailed quantitative analysis of the specific heat in the 0.5- to 200-K temperature range for almost dry L-cysteine and its dimer, L-cystine, amino acids is presented. We report the occurrence of a sharp first-order transition at ∼76 K for L-cysteine associated with the thiol group ordering which was successfully modeled with the two-dimensional Ising model. We demonstrated that quantum rotors, two-level systems (TLS), Einstein oscillators, and acoustic phonons (the Debye model) are essential ingredients to correctly describe the overall experimental data. Our analysis pointed out the absence of the TLS contribution to the low temperature specific heat of L-cysteine. This result was similar to that found in other noncrystalline amorphous materials, e.g., amorphous silicon, low density amorphous water, and ultrastable glasses. L-cystine presented an unusual nonlinear acoustic dispersion relation ω(q)=vq0.95 and a Maxwell-Boltzmann-type distribution of tunneling barriers. The presence of Einstein oscillators with ΘE∼70 K was common in both systems and adequately modeled the boson peak contributions.

Studies on infrared drying of paper, use of integrating spheres in FTIR measurements, and heat and mass transfer inside paper

Energy Technology Data Exchange (ETDEWEB)

Ojala, K

1994-12-31

The effect of various factors on the efficiency of infrared dryers has been studied by modelling and simulation of radiative heat transfer in these dryers. Generally, 20-35 % of the radiation from electrical IR dryers becomes absorbed by the web, whereas in the case of a gas-fired dryer 30-50 % of the energy becomes absorbed. The efficiency is strongly dependent on the dryer design, power, geometry, cleanness, and the material to be dried. Ways to improve the efficiency of installed dryers are proposed and tested. The escape of radiation from the system can be reduced, the optical properties of the surfaces can be improved, the amount of cooling can be reduced in low power circumstances, and the way of installation can be changed. A very promising method is to install the dryer far from the web and attach side flanges of high emissivity beside the dryer. The spectral properties of papers and dryer materials are studied with an FTIR spectrometer using integrating sphere techniques. The heat and mass transfer processes inside the paper during drying has been studied. The drying model was applied to the simulation of the wetting experiments. The approximate magnitude for the permeability of liquid water inside the web was determined by adapting the liquid movement to these results. Applying this enhanced model, the flows of liquid water and vapor inside paper have been studied during the drying process on a hot cylinder

Lower pressure heating steam is practical for the distributed dry dilute sulfuric acid pretreatment.

Science.gov (United States)

Shao, Shuai; Zhang, Jian; Hou, Weiliang; Qureshi, Abdul Sattar; Bao, Jie

2017-08-01

Most studies paid more attention to the pretreatment temperature and the resulted pretreatment efficiency, while ignored the heating media and their scalability to an industry scale. This study aimed to use a relative low pressure heating steam easily provided by steam boiler to meet the requirement of distributed dry dilute acid pretreatment. The results showed that the physical properties of the pretreated corn stover were maintained stable using the steam pressure varying from 1.5, 1.7, 1.9 to 2.1MPa. Enzymatic hydrolysis and high solids loading simultaneous saccharification and fermentation (SSF) results were also satisfying. CFD simulation indicated that the high injection velocity of the low pressure steam resulted in a high steam holdup and made the mixing time of steam and solid corn stover during pretreatment much shorter in comparison with the higher pressure steam. This study provides a design basis for the boiler requirement in distributed pretreatment concept. Copyright © 2017 Elsevier Ltd. All rights reserved.

Generalization of drying curves in conductive/convective drying of cellulose

Directory of Open Access Journals (Sweden)

M. Stenzel

2003-03-01

Full Text Available The objective of this work is to analyze the possibility of applying the drying curves generalization methodology to the conductive/convective hot plate drying of cellulose. The experiments were carried out at different heated plate temperatures and air velocities over the surface of the samples. This kind of approach is very interesting because it permits comparison of the results of different experiments by reducing them to only one set, which can be divided into two groups: the generalized drying curves and the generalized drying rate curves. The experimental apparatus is an attempt to reproduce the operational conditions of conventional paper dryers (ratio of paper/air movement and consists of a metallic box heated by a thermostatic bath containing an upper surface on which the cellulose samples are placed. Sample material is short- and long-fiber cellulose sheets, about 1 mm thick, and ambient air was introduced into the system by a adjustable blower under different conditions. Long-fiber cellulose generalized curves were obtained and analyzed first individually and then together with the short-fiber cellulose results from Motta Lima et al. (2000 a,b. Finally, a set of equations to fit the generalized curves obtained was proposed and discussed.

Thermal design of heat-exchangeable reactors using a dry-sorbent CO2 capture multi-step process

International Nuclear Information System (INIS)

Moon, Hokyu; Yoo, Hoanju; Seo, Hwimin; Park, Yong-Ki; Cho, Hyung Hee

2015-01-01

The present study proposes a multi-stage CO 2 capture process that incorporates heat-exchangeable fluidized-bed reactors. For continuous multi-stage heat exchange, three dry regenerable sorbents: K 2 CO 3 , MgO, and CaO, were used to create a three-stage temperature-dependent reaction chain for CO 2 capture, corresponding to low (50–150 °C), middle (350–650 °C), and high (750–900 °C) temperature stages, respectively. Heat from carbonation in the high and middle temperature stages was used for regeneration for the middle and low temperature stages. The feasibility of this process is depending on the heat-transfer performance of the heat-exchangeable fluidized bed reactors as the focus of this study. The three-stage CO 2 capture process for a 60 Nm 3 /h CO 2 flow rate required a reactor area of 0.129 and 0.130 m 2 for heat exchange between the mid-temperature carbonation and low-temperature regeneration stages and between the high-temperature carbonation and mid-temperature regeneration stages, respectively. The reactor diameter was selected to provide dense fluidization conditions for each bed with respect to the desired flow rate. The flow characteristics and energy balance of the reactors were confirmed using computational fluid dynamics and thermodynamic analysis, respectively. - Highlights: • CO 2 capture process is proposed using a multi-stage process. • Reactor design is conducted considering heat exchangeable scheme. • Reactor surface is designed by heat transfer characteristics of fluidized bed

Heat pump dryers theory, design and industrial applications

CERN Document Server

Alves-Filho, Odilio

2015-01-01

Explore the Social, Technological, and Economic Impact of Heat Pump Drying Heat pump drying is a green technology that aligns with current energy, quality, and environmental concerns, and when compared to conventional drying, delivers similar quality at a lower cost. Heat Pump Dryers: Theory, Design and Industrial Applications details the progression of heat pump drying-from pioneering research and demonstration work to an applied technology-and establishes principles and theories that can aid in the successful design and application of heat pump dryers. Based on the author's personal experience, this book compares heat pump dryers and conventional dryers in terms of performance, quality, removal rate, energy utilization, and the environmental effect of both drying processes. It includes detailed descriptions and layouts of heat pump dryers, outlines the principles of operation, and explains the equations, diagrams, and procedures used to form the basis for heat pump dryer dimensioning and design. The author ...

Use of dried cassava root to replace corn in supplementation of Holstein cows grazing and consuming spontaneously, apparent digestibility and energy metabolism

Directory of Open Access Journals (Sweden)

Ádler Carvalho da Silva

2015-07-01

Full Text Available The development of this experiment intended to evaluate the effect of replacing ground corn for dried and ground cassava roots with the levels of 0%, 25%, 50%, 75% and 100% in the experimental supplements for lactating cows kept on tropical irrigated and fertilized pastures. Ten Holstein cows were divided into two 5x5 Latin squares, with an initial lactation average of 150 days, 22 kg/day of average milk production of lactation and approximate initial average body eight of 603 kg. The animals were kept in pasture constituted by elephant grass (Pennisetum purpureum, SCHUM cv Pioneer, associated with Tifton 85 grass (Cynodon nlemfuensis, irrigated and fertilized with 600 kg of nitrogen per hectare/year. No significant effects on the substitution of ground corn for dried and ground cassava roots in the concentrate (P>0.05 over the spontaneous consumption of the total diet, with estimated average of 20.61 kg/DM/animal/day, apparent digestibility of DM with estimated average of 59.60% and energy balance with estimated average of +6.36 Mcal day-1. The results of this study demonstrate that the cassava root can be used as an energy source of high nutritional value for supplementation of lactating cows grazing on tropical pastures, similar to corn results.

Assessment of Osmotic Pre-Drying Treatment on Drying Rates of ...

African Journals Online (AJOL)

Akorede

of heat, chemical method, physical method and drying (Morris et al., 2004). ... 3Department of Agricultural and Bioresources Engineering, Federal University Oye-Ekiti, Oye-Ekiti, Nigeria. ..... Unpublished Master's Degree Thesis submitted to the.

Effect of drying conditions on drying kinetics and quality of aromatic Pandanus amaryllifolius leaves

OpenAIRE

Rayaguru, Kalpana; Routray, Winny

2010-01-01

Pandanus amaryllifolius is a plant with aromatic leaves, which impart the characteristic flavour of aromatic rice. The quality of aromatic Pandanus leaves dried at low temperature (35 °C) and low RH (27%) in a heat pump dryer was evaluated and compared with those obtained from hot air drying at 45 °C. Thin-layer drying kinetics has been studied for both the conditions. To determine the kinetic parameters, the drying data were fitted to various semi-theoretical models. The goodness of fit was ...

System Model of Heat and Mass Transfer Process for Mobile Solvent Vapor Phase Drying Equipment

Directory of Open Access Journals (Sweden)

Shiwei Zhang

2014-01-01

Full Text Available The solvent vapor phase drying process is one of the most important processes during the production and maintenance for large oil-immersed power transformer. In this paper, the working principle, system composition, and technological process of mobile solvent vapor phase drying (MVPD equipment for transformer are introduced in detail. On the basis of necessary simplification and assumption for MVPD equipment and process, a heat and mass transfer mathematical model including 40 mathematical equations is established, which represents completely thermodynamics laws of phase change and transport process of solvent, water, and air in MVPD technological processes and describes in detail the quantitative relationship among important physical quantities such as temperature, pressure, and flux in key equipment units and process. Taking a practical field drying process of 500 KV/750 MVA power transformer as an example, the simulation calculation of a complete technological process is carried out by programming with MATLAB software and some relation curves of key process parameters changing with time are obtained such as body temperature, tank pressure, and water yield. The change trend of theoretical simulation results is very consistent with the actual production record data which verifies the correctness of mathematical model established.

CFD Analysis on the Passive Heat Removal by Helium and Air in the Canister of Spent Fuel Dry Storage System

Energy Technology Data Exchange (ETDEWEB)

Shin, Do Young; Jeong, Ui Ju; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

2016-05-15

In the current commercial design, the canister of the dry storage system is mainly backfilled with helium gas. Helium gas shows very conductive behavior due to high thermal conductivity and small density change with temperature. However, other gases such as air, argon, or nitrogen are expected to show effective convective behavior. Thus these are also considered as candidates for the backfill gas to provide effective coolability. In this study, to compare the dominant cooling mechanism and effectiveness of cooling between helium gas and air, a computational fluid dynamics (CFD) analysis for the canister of spent fuel dry storage system with backfill gas of helium and air is carried out. In this study, CFD simulations for the helium and air backfilled gas for dry storage system canister were carried out using ANSYS FLUENT code. For the comparison work, two backfilled fluids were modeled with same initial and boundary conditions. The observed major difference can be summarized as follows. - The simulation results showed the difference in dominant heat removal mechanism. Conduction for helium, and convection for air considering Reynolds number distribution. - The temperature gradient inside the fuel assembly showed that in case of air, more effective heat mixing occurred compared to helium.

Utilization of heat from High Temperature Reactors (HTR) for dry reforming of methane

Science.gov (United States)

Jastrząb, Krzysztof

2018-01-01

One of the methods for utilization of waste carbon dioxide consists in reaction of methane with carbon dioxide, referred to as dry reforming of methane. It is an intensely endothermic catalytic process that takes place at the temperature above 700°C. Reaction of methane with carbon dioxide leads to formation of synthesis gas (syngas) that is a valuable chemical raw material. The energy that is necessary for the process to take place can be sourced from High Temperature Nuclear Reactors (HTR). The completed studies comprises a series of thermodynamic calculations and made it possible to establish optimum conditions for the process and demand for energy from HTR units. The dry reforming of methane needs also a catalytic agent with appropriate activity, therefore the hydrotalcite catalyser with admixture of cerium and nickel, developed at AGH University of Technology seems to be a promising solution. Thus, the researchers from the Institute for Chemical Processing of Coal (IChPW) in Zabrze have developed a methodology for production of the powdery hydrotalcite catalyser and investigated catalytic properties of the granulate obtained. The completed experiments confirmed that the new catalyser demonstrated high activity and is suitable for the process of methane dry reforming. In addition, optimum parameters of the were process (800°C, CO2:CH4 = 3:1) were established as well. Implementation of the technology in question into industrial practice, combined with utilization of HTR heat can be a promising method for management of waste carbon dioxide and may eventually lead to mitigation of the greenhouse effect.

Dry patch formed boiling and burnout in potassium pool boiling

International Nuclear Information System (INIS)

Michiyoshi, I.; Takenaka, N.; Takahashi, O.

1986-01-01

Experimental results are presented on dry patch formed boiling and burnout in saturated potassium pool boiling on a horizontal plane heater for system pressures from 30 to 760 torr and liquid levels from 5 to 50 mm. The dry patch formation occurs in the intermittent boiling which is often encountered when liquid alkali metals are used under relatively low pressure conditions. Burnout is caused from both continuous nucleate and dry patch formed boiling. The burnout heat flux together with nucleate boiling heat transfer coefficients are empirically correlated with system pressures. A model is also proposed to predict the minimum heat flux to form the dry patch. (author)

Analysis of the use of waste heat obtained from coal-fired units in Organic Rankine Cycles and for brown coal drying

International Nuclear Information System (INIS)

Łukowicz, Henryk; Kochaniewicz, Andrzej

2012-01-01

The ever-increasing restrictions on greenhouse gas emissions have created a need for new energy technologies. One way to meet these new requirements is to optimise the efficiency of power units. This paper presents two energy technologies that, if used, will increase the efficiency of electricity generation. One of the most effective ways to improve the efficiency of brown coal-fired units is by drying the coal that is fed into the boiler. Here, we describe a technology that uses the waste heat obtained from exhaust gases. This paper also presents an analysis of the feasibility of and potential for using waste heat obtained from exhaust gases to feed Organic Rankine Cycles (ORCs). Several low-temperature working fluids were considered, which were selected based on properties that were best suited for these types of cycles. The impact of these working fluids on the efficiency and capacity of the ORC was also examined. The calculations for ORCs fed with waste heat obtained from exhaust gases from hard coal- and brown coal-fired boilers were compared. -- Highlights: ► We describe a technology that uses the waste heat obtained from exhaust gases. ► The impact of using different working fluids with a low boiling point is examined. ► We describe integrating the ORC with the power unit. ► The use of waste heat from boiler exhaust gases to dry brown coal is proposed. ► We demonstrate a possible increase in power unit efficiency.

Negative specific heat with trapped ultracold quantum gases

Science.gov (United States)

Strzys, M. P.; Anglin, J. R.

2014-01-01

The second law of thermodynamics normally prescribes that heat tends to disperse, but in certain cases it instead implies that heat will spontaneously concentrate. The spontaneous formation of stars out of cold cosmic nebulae, without which the universe would be dark and dead, is an example of this phenomenon. Here we show that the counter-intuitive thermodynamics of spontaneous heat concentration can be studied experimentally with trapped quantum gases, by using optical lattice potentials to realize weakly coupled arrays of simple dynamical subsystems, so that under the standard assumptions of statistical mechanics, the behavior of the whole system can be predicted from ensemble properties of the isolated components. A naive application of the standard statistical mechanical formalism then identifies the subsystem excitations as heat in this case, but predicts them to share the peculiar property of self-gravitating protostars, of having negative micro-canonical specific heat. Numerical solution of real-time evolution equations confirms the spontaneous concentration of heat in such arrays, with initially dispersed energy condensing quickly into dense ‘droplets’. Analysis of the nonlinear dynamics in adiabatic terms allows it to be related to familiar modulational instabilities. The model thus provides an example of a dictionary mesoscopic system, in which the same non-trivial phenomenon can be understood in both thermodynamical and mechanical terms.

Effects of steam-microwave blanching and different drying processes on drying characteristics and quality attributes of Thunbergia laurifolia Linn. leaves.

Science.gov (United States)

Phahom, Traiphop; Phoungchandang, Singhanat; Kerr, William L

2017-08-01

Dried Thunbergia laurifolia leaves are usually prepared using tray drying, resulting in products that have lost substantial amounts of bioactive compounds and antioxidant activity. The maturity of the raw material, blanching techniques and drying methods were investigated in order to select the best condition to produce high qualities of dried T. laurifolia leaves. The 1st stage of maturity was selected and steam-microwave blanching (SMB) for 4 min was adequate for blanching leading to the maximum recovery of bioactive compounds. The modified Halsey model was the best desorption isotherm model. A new drying model proposed in this study was the best to fit the drying curves as compared to five common drying models. Moisture diffusivities were increased with the increase of drying temperature when combining SMB and heat pump-dehumidified drying. Microwave heat pump-dehumidified drying (MHPD) provided the shortest drying time, high specific moisture extraction rate (SMER) and could reduce drying time by 67.5% and increase caffeic acid and quercetin by 51.24% and 60.89%, respectively. MHPD was found to be the best drying method and provided the highest antioxidant activity and bioactive compounds content, high SMER and short drying time. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Impact of mild heat stress on dry matter intake, milk yield and milk composition in mid-lactation Holstein dairy cows in a temperate climate.

Science.gov (United States)

Gorniak, Tobias; Meyer, Ulrich; Südekum, Karl-Heinz; Dänicke, Sven

2014-01-01

The aim of the present study was to evaluate the impact of summer temperatures in a temperate climate on mid-lactation Holstein dairy cows. Therefore, a data set was examined comprising five trials with dairy cows conducted at the experimental station of the Friedrich-Loeffler-Institute in Braunschweig, Germany. The temperature-humidity index (THI) was calculated using temperature and humidity data from the barns recorded between January 2010 and July 2012. By using a generalised additive mixed model, the impact of increasing THI on dry matter intake, milk yield and milk composition was evaluated. Dry matter intake and milk yield decreased when THI rose above 60, whilst water intake increased in a linear manner beyond THI 30. Furthermore, milk protein and milk fat content decreased continuously with increasing THI. The present results revealed that heat stress exists in Lower Saxony, Germany. However, further research is necessary to describe the mode of action of heat stress. Especially, mild heat stress has to be investigated in more detail and appropriate heat stress thresholds for temperate climates have to be developed.

Effect Of Dried Whey Milk Supplement On Some Blood Biochemical And Immunological Indices In Relation To Growth Performance Of Heat Stressed Bovine baladi Calves

International Nuclear Information System (INIS)

ABDALLA, E.B.; EL-MASRY, K.A.; TEAMA, F.E.; EMARA, S.S.

2009-01-01

This experiment was carried out under hot environmental conditions, where temperature-humidity index was equivalent to 86 - 90 and 78 - 80 during day and night, respectively. Twelve bovine Baladi calves of 8 - 10 months old and 112 kg average initial live body weight were used in this study. The calves were divided into two groups of 6 animals each to study the effect of supplementation of dried whey milk on some blood biochemical and immunological indices and growth performance of calves under hot weather conditions of Egypt. The results showed that supplementation of dried whey milk to the diet of heat-stressed calves at the level of 150 g / calf / day reduced significantly each of respiration rate and rectal temperature as well as serum lipid concentrations and their fractions e.g. total cholesterol and phospholipids. Also, dried whey milk supplement caused a significant decline in both AST and ALT activities and reduced significantly alpha globulin concentration, while non-significant changes were observed in each of beta globulin, gamma globulin and immunoglobulin G. However, supplementing dried whey milk to growing calves increased significantly serum concentrations of total protein, albumin, calcium, phosphorous, T 3 and T 4 . Moreover, dried whey milk improved significantly both feed efficiency and daily gain of growing calves. It could be concluded that addition of dried whey milk to the diet reduced rectal temperature and respiration rate and induced an improvement in most blood biochemical parameters and growth performance of heat-stressed bovine Baladi calves.

Market opportunities for solar drying

International Nuclear Information System (INIS)

Voskens, R.G.J.H.; Out, P.G.; Schulte, B.

2000-01-01

One of the most promising applications for solar heating is the drying of agricultural products. The drying of agricultural products requires large quantities of low temperature air, in many cases, on a year-round basis. Low cost air-based collectors can provide heated air at solar collection efficiencies of 30 to 70%. In 1998/1999 a study was commissioned to better understand the technical and economic potential for solar drying of agricultural products in the world. The practical potential for solar drying was then determined for 59 crops and 22 regions. The world market for solar drying can be divided into three market segments: 1) mechanical drying T 50 deg. C; 3) sun drying. The most promising market for solar drying is generally market segment 1. For this segment the potential amount of energy displaced by solar is in between 216 770 PJ (World-wide). For Western Europe this potential is estimated between 23 88 PJ and for Eastern Europe between 7 and 13 PJ. A different market introduction strategy is required for each market segment. A total of 13 combinations of crops and regions are selected that appear to have the highest practical potential for solar drying. In the Netherlands a programme of activities was carried out by Ecofys and other organisations, to identify and develop the market potential for solar (assisted) drying of agricultural products. A promotional campaign for the use of renewable energy in the (promising) flower bulb sector is planned on a short-term basis to speed up market developments. It can be concluded that there is a large market for solar drying in the World as well as in Europe. (au)

Short communication Effects of drying procedures on chemical ...

African Journals Online (AJOL)

jancik.filip

2016-12-31

Dec 31, 2016 ... Another drying procedure included pre-treatment by heating in a ... freeze-drying method and that this procedure is useful for forage analyses and evaluation. ... oven drying (OD) and innovative drying procedures (pre-treatments .... This was probably caused by losses of compounds such as ammonia and.

Development of evaluation method for heat removal design of dry storage facilities. pt. 1. Heat removal test on vault storage system of cross flow type

International Nuclear Information System (INIS)

Sakamoto, Kazuaki; Koga, Tomonari; Wataru, Masumi; Hattori, Yasuo

1997-01-01

The report describes the result of heat removal test of passive cooling vault storage system of cross flow type using 1/5 scale model. Based on a prospect of steady increase in the amount of spent fuel, it is needed to establish large capacity dry storage technologies for spent fuel. Air flow patterns, distributions of air temperature and velocity were measured, by which heat removal characteristics of the system were made clear. Air flow patterns in the storage module depended on the ratio of the buoyant force to the inertial force; the former generated by the difference of air temperatures and the height of the storage module, the latter by the difference of air densities between the outlet of the storage module and ambience and the height of the chimney of the storage facility. A simple method to estimate air flow patterns in the storage module was suggested, where Ri(Richardson) number was applied to represent the ratio. Moreover, heat transfer coefficient from a model of storage tube to cooling air was evaluated, and it was concluded that the generalized expression of heat transfer coefficient for common heat exchangers could be applied to the vault storage system of cross flow type, in which dozens of storage tubes were placed in a storage module. (author)

Qualidade de sementes de tomate influenciada pelos tratamentos térmico e osmótico Tomato seeds quality affected by dry heat and osmotic treatments

Directory of Open Access Journals (Sweden)

Flávio de Souza Lopes

2004-09-01

Full Text Available O tratamento térmico via calor seco, visando o controle de patógenos associado às sementes, pode causar danos à qualidade fisiológica das mesmas, que podem ser recuperados, por meio do condicionamento osmótico. Avaliou-se o efeito do tratamento térmico via calor seco na qualidade sanitária e fisiológica das sementes de tomate, assim como a influência do condicionamento osmótico na qualidade fisiológica das sementes submetidas à termoterapia. As sementes das cultivares Quadrado Mix, Topmec e Calmec VFN foram expostas ao tratamento térmico a 70; 72,5 e 75ºC, em estufa com circulação forçada, por períodos de zero, 48; 96 e 120 horas. O período zero, sem a aplicação de calor, foi considerado como testemunha. Posteriormente, estas sementes foram avaliadas quanto à sanidade, condicionadas em solução aerada de polietilenoglicol a 0,0 e -1,0 MPa e submetidas à avaliação do teor de água, da germinação e do vigor. Pelos resultados pode-se concluir que o tratamento térmico via calor seco não foi eficiente em eliminar os patógenos associados às sementes de tomate, dependendo da cultivar avaliada. Períodos prolongados de exposição ao calor seco causaram danos à qualidade fisiológica das sementes de tomate, que não foram recuperados com o subseqüente condicionamento osmótico.The dry heat treatment aiming to control microorganisms in the seeds can cause damage to the physiological quality of seeds. Osmotic conditioning can be useful tool for recovering the physiological quality of the heat treated seeds. The study was carried out to evaluate the effects of dry heat treatments on the tomato seeds sanitary and physiologic quality, as well as to analyze the effect of the osmotic conditioning on seeds submitted to dry heat treatment. The seeds of cultivars Quadrado Mix, Topmec and Calmec VFN were heated at 70; 72.5 and 75ºC by periods of zero, 48; 96 and 120 hours. After the heat treatment, the seeds were evaluated for

Dry coolers and air-condensing units (Review)

Science.gov (United States)

Milman, O. O.; Anan'ev, P. A.

2016-03-01

The analysis of factors affecting the growth of shortage of freshwater is performed. The state and dynamics of the global market of dry coolers used at electric power plants are investigated. Substantial increase in number and maximum capacity of air-cooled condensers, which have been put into operation in the world in recent years, are noted. The key reasons facilitating the choice of developers of the dry coolers, in particular the independence of the location of thermal power plant from water sources, are enumerated. The main steam turbine heat removal schemes using air cooling are considered, their comparison of thermal efficiency is assessed, and the change of three important parameters, such as surface area of heat transfer, condensate pump flow, and pressure losses in the steam exhaust system, are estimated. It is shown that the most effective is the scheme of direct steam condensation in the heat-exchange tubes, but other schemes also have certain advantages. The air-cooling efficiency may be enhanced much more by using an air-cooling hybrid system: a combination of dry and wet cooling. The basic applied constructive solutions are shown: the arrangement of heat-exchange modules and the types of fans. The optimal mounting design of a fully shopassembled cooling system for heat-exchange modules is represented. Different types of heat-exchange tubes ribbing that take into account the operational features of cooling systems are shown. Heat transfer coefficients of the plants from different manufacturers are compared, and the main reasons for its decline are named. When using evaporative air cooling, it is possible to improve the efficiency of air-cooling units. The factors affecting the faultless performance of dry coolers (DC) and air-condensing units (ACU) and the ways of their elimination are described. A high velocity wind forcing reduces the efficiency of cooling systems and creates preconditions for the development of wind-driven devices. It is noted that

On adaptive time stepping for large-scale parabolic problems: Computer simulation of heat and mass transfer in vacuum freeze-drying

Czech Academy of Sciences Publication Activity Database

Georgiev, K.; Kosturski, N.; Margenov, S.; Starý, Jiří

2009-01-01

Roč. 226, č. 2 (2009), s. 268-274 ISSN 0377-0427 Institutional research plan: CEZ:AV0Z30860518 Keywords : Vacuum freeze drying * Zeolites * Heat and mass transfer * Finite element method * MIC(0) preconditioning Subject RIV: BA - General Mathematics Impact factor: 1.292, year: 2009 http://apps.isiknowledge.com

Transport phenomena and drying of solids and particulate materials

CERN Document Server

Lima, AG

2014-01-01

The purpose of this book, Transport Phenomena and Drying of Solids and Particulate Materials, is to provide a collection of recent contributions in the field of heat and mass transfer, transport phenomena, drying and wetting of solids and particulate materials. The main benefit of the book is that it discusses some of the most important topics related to the heat and mass transfer in solids and particulate materials. It includes a set of new developments in the field of basic and applied research work on the physical and chemical aspects of heat and mass transfer phenomena, drying and wetting processes, namely, innovations and trends in drying science and technology, drying mechanism and theory, equipment, advanced modelling, complex simulation and experimentation. At the same time, these topics will be going to the encounter of a variety of scientific and engineering disciplines. The book is divided in several chapters that intend to be a resume of the current state of knowledge for benefit of professional c...

Determination of the most economical drying schedule and air velocity in softwood drying

Energy Technology Data Exchange (ETDEWEB)

Salin, J.G.

2001-12-01

Simulation models for conventional softwood drying have been available and have also been used by kiln operators for many years. For instance models for Scots pine and Norway spruce, dried at temperatures below about 80 deg C, are in use in Sweden, Finland and Norway. These models predict drying rates as a function of climate (schedule) and air velocity. The models thus give a direct basis for calculation of instantaneous energy demand for moisture evaporation and ventilation. There is further a direct relationship between the air velocity in the space between the board layers in the kiln stack and the electrical power demand by the circulation fans. Finally, the smaller energy consumption associated with heat losses through kiln walls and the accumulated heat in timber etc. can be estimated with sufficient accuracy. Instantaneous energy costs can thus be calculated for each part of a drying schedule. Capital costs associated with kiln investment and maintenance, personnel, insurance etc can be accounted for as an hourly cost, which is basically independent of whether timber is dried fast or slowly. A slow drying process thus accumulates more capital costs per m 3 timber. In this way it is possible to calculate the total instantaneous drying cost (Euro/m{sup 3}/h or Euro/m3/MC%) and the overall total cost (Euro or Euro/m{sup 3}). Some results obtained with a simulation model equipped with such a cost calculation are presented in the paper. A rapidly increasing drying cost is seen when the final MC is lowered. By minimising the instantaneous cost, an optimal drying schedule can be determined for a given fixed air velocity. Finally an optimal air velocity - constant or varying - can be found in the same way.

Thermalhydraulic behavior of electrically heated rod during a critical heat flux transient

International Nuclear Information System (INIS)

Lima, Rita de Cassia Fernandes de; Carajilescov, Pedro

1997-01-01

In nuclear reactors, the occurrence of critical heat flux leads to fuel rod overheating with clad fusion and radioactive products leakage. To predict the effects of such phenomenon, experiments are performed using electrically heated rods to simulate operational and accidental conditions of nuclear fuel rods. In the present work, a theoretical analysis of the drying and rewetting front propagation is performed during a critical heat flux experiment, starting with the application of slope of electrical power from steady state condition. After the occurrence of critical heat flux, the drying front propagation is predicted. After a few seconds, a power cut is considered and the rewetting front behavior is analytically observed. Studies done with several values of coolant mass flow rate show that this variable has more influence on the drying front velocity than on the rewetting one. (author)

Semi-Dried Fruits and Vegetables

Directory of Open Access Journals (Sweden)

Gamze Uysal Seçkin

2015-12-01

Full Text Available Since ancient times, the preservation of fruit and vegetables is an ancient method of drying. Sun drying method has been used more widely. In general, consumer-ready products are dried fruits, while the dried vegetables are the foods subjected to the rehydration processes such as boiling, heating and baking before consumption. In recent years, new products with high eating quality have been attempted to achieve without losing characteristic of raw material. With the improving of food technology, using developed methods (pH reduction with reducing aw, slight heating, preservatives use etc. as protective agent, and using a combination of a low rate as an alternative to traditional food preservation process, products have been obtained without changing original characteristics of food. ‘Semi-dried 'or 'medium moist 'products with little difference between the taste and texture of the product with a damp have gained importance in recent years in terms of consumer preferences. Vegetables or fruits, which have water activity levels between 0.50 and 0.95 and the moisture content of between 26% and 60%, are called 'medium moist fruit or vegetables'. Two different manufacturing process to obtain a semi-dried or intermediate moisture products are applied. First, fully dried fruits and vegetables to be rehydrated with water are brought to the desired level of their moisture content. Second, in the first drying process, when the product moisture content is reduced to the desired level, the drying process is finished. The semi-dried products are preferred by consumers because they have a softer texture in terms of eating quality and like fresh products texture.

Modelling Condensation and Simulation for Wheat Germ Drying in Fluidized Bed Dryer

Directory of Open Access Journals (Sweden)

Der-Sheng Chan

2018-06-01

Full Text Available A low-temperature drying with fluidized bed dryer (FBD for wheat germ (WG stabilization could prevent the loss of nutrients during processing. However, both evaporation and condensation behaviors occurred in sequence during FBD drying of WG. The objective of this study was to develop a theoretical thin-layer model coupling with the macro-heat transfer model and the bubble model for simulating both the dehydration and condensation behaviors of WG during low-temperature drying in the FBD. The experimental data were also collected for the model modification. Changes in the moisture content of WG, the air temperature of FBD chamber, and the temperature of WG during drying with different heating approaches were significantly different. The thermal input of WG drying with short heating time approach was one-third of that of WG drying with a traditional heating approach. The mathematical model developed in this study could predict the changes of the moisture content of WG and provide a good understanding of the condensation phenomena of WG during FBD drying.

Process Analytical Technology in Freeze-Drying: Detection of the Secondary Solute + Water Crystallization with Heat Flux Sensors.

Science.gov (United States)

Wang, Qiming; Shalaev, Evgenyi

2018-04-01

In situ and non-invasive detection of solute crystallization during freeze-drying would facilitate cycle optimization and scale-up from the laboratory to commercial manufacturing scale. The objective of the study is to evaluate heat flux sensor (HFS) as a tool for monitoring solute crystallization and other first-order phase transitions (e.g., onset of freezing). HFS is a thin-film differential thermopile, which acts as a transducer to generate an electrical signal proportional to the total heat applied to its surface. In this study, HFS is used to detect both primary (ice formation) and secondary (also known as eutectic) solute + water crystallization during cooling and heating of solutions in a freeze-dryer. Binary water-solute mixtures with typical excipients concentrations (e.g., 0.9% of NaCl and 5% mannitol) and fill volumes (1 to 3 ml/vial) are studied. Secondary crystallization is detected by the HFS during cooling in all experiments with NaCl solutions, whereas timing of mannitol crystallization depends on the cooling conditions. In particular, mannitol crystallization takes place during cooling, if the cooling rate is lower than the critical value. On the other hand, if the cooling rate exceeds the critical cooling rate, mannitol crystallization during cooling is prevented, and crystallization occurs during subsequent warming or annealing. It is also observed that, while controlled ice nucleation allows initiation of the primary freezing event in different vials simultaneously, there is a noticeable vial-to-vial difference in the timing of secondary crystallization. The HFS could be a valuable process monitoring tool for non-invasive detection of various crystallization events during freeze-drying manufacturing.

Numerical characterisation of one-step and three-step solar air heating collectors used for cocoa bean solar drying.

Science.gov (United States)

Orbegoso, Elder Mendoza; Saavedra, Rafael; Marcelo, Daniel; La Madrid, Raúl

2017-12-01

In the northern coastal and jungle areas of Peru, cocoa beans are dried using artisan methods, such as direct exposure to sunlight. This traditional process is time intensive, leading to a reduction in productivity and, therefore, delays in delivery times. The present study was intended to numerically characterise the thermal behaviour of three configurations of solar air heating collectors in order to determine which demonstrated the best thermal performance under several controlled operating conditions. For this purpose, a computational fluid dynamics model was developed to describe the simultaneous convective and radiative heat transfer phenomena under several operation conditions. The constructed computational fluid dynamics model was firstly validated through comparison with the data measurements of a one-step solar air heating collector. We then simulated two further three-step solar air heating collectors in order to identify which demonstrated the best thermal performance in terms of outlet air temperature and thermal efficiency. The numerical results show that under the same solar irradiation area of exposition and operating conditions, the three-step solar air heating collector with the collector plate mounted between the second and third channels was 67% more thermally efficient compared to the one-step solar air heating collector. This is because the air exposition with the surface of the collector plate for the three-step solar air heating collector former device was twice than the one-step solar air heating collector. Copyright © 2017 Elsevier Ltd. All rights reserved.

An experimental study on natural draft-dry cooling tower as part of the passive system for the residual decay heat removal

International Nuclear Information System (INIS)

Caruso, G.; Fatone, M.; Naviglio, A.

2007-01-01

An experimental apparatus has been built in order to perform sensitivity analysis on the performance of a natural draft-dry cooling tower. This component plays an important role in the passive system for the residual heat decay removal foreseen in the MARS reactor and in the GCFR of the Generation IV reactors. The sensitivity analysis has investigated: 1) the heat exchanger arrangement; two different arrangements have been considered: a horizontal arrangement, in which a system of electrical heaters are placed at the inlet cross section of the tower, and a vertical arrangement, with the heaters distributed vertically around the circumference of the tower. 2) The shape of the cooling tower; by varying the angle of the shell inclination it is possible to obtain a different shape for the tower itself. An upper and a lower angle inclination were modified and by a calculation procedure eleven different configuration were selected. 3) The effect of cross wind on the tower performance. An equation-based procedure to design the dry-cooling tower is presented. In order to evaluate the influence of the shape and the heat exchanger arrangement on the performance of the cooling tower, a geometrical factor (FG) and a thermal factor (FT) are introduced. By analyzing the experimental results, engineering design relations are obtained to model the cooling tower performance. The comparison between the experimental heat transfer coefficient and the heat transfer coefficient obtained by the mathematical procedure shows that there is a good agreement. The obtained results show that it is possible to evaluate the shape and the heat exchanger arrangement to optimize the performance of the cooling tower either in wind-less condition either in presence of cross wind. (authors)

Burning Eye Syndrome: Do Neuropathic Pain Mechanisms Underlie Chronic Dry Eye?

Science.gov (United States)

Kalangara, Jerry P; Galor, Anat; Levitt, Roy C; Felix, Elizabeth R; Alegret, Ramon; Sarantopoulos, Constantine D

2016-04-01

Dry eye is a multi-factorial disorder that manifests with painful ocular symptoms and visual disturbances, which can only be partly attributed to tear dysfunction. This disorder may also involve neuroplasticity in response to neuronal injury. This review will emphasize the key characteristics of dry eye pain and its pathologic mechanisms, making the argument that a subset of dry eye represents a neuropathic pain disorder of the eye, more appropriately called "burning eye syndrome." A literature review was conducted using a PubMed search focusing on dry eye, corneal nociception, and neuropathic pain. Articles were reviewed and those discussing clinical course, pathophysiology, and neuronal regulation of chronic ocular pain as related to dry eye were summarized. We found that there is a discordance between ocular pain and dryness on the ocular surface. Although tear dysfunction may be one of the initial insults, its persistence may be associated with repeated ocular sensory nerve injury leading to an acute-to-chronic pain transition associated with neuropathologic changes (peripheral and central sensitization), neuronal dysfunction, and spontaneous ocular pain. Dry eye is becoming a major health concern due to its increasing incidence, significant morbidity, and economic burden. Recent evidence suggests that a subset of dry eye may be better represented as a chronic neuropathic pain disorder due to its features of dysesthesia, spontaneous pain, allodynia, and hyperalgesia. Future therapies targeted at the underlying neuroplasticity may yield improved efficacy for patients with this subset of dry eye, which we term "burning eye syndrome." © 2015 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Impact of non-binder ingredients and molecular weight of polymer binders on heat assisted twin screw dry granulation.

Science.gov (United States)

Liu, Y; Thompson, M R; O'Donnell, K P

2018-01-30

Two grades of commercial AFFINISOL™ HPMC HME were used as polymer binders to explore the influence of polymer viscosity and concentration on a novel heat assisted dry granulation process with a twin screw extruder. Contributions of other non-binder ingredients in the formulations were also studied for lactose, microcrystalline cellulose and an active pharmaceutical ingredient of caffeine. As sensitive indicators of processing conditions that expose the drug to high internally generated heat, dehydration of α-lactose monohydrate and polymorphic transformation of caffeine were monitored by differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD). Additionally, any decomposition of caffeine was determined by high-performance liquid chromatography (HPLC). Granular samples were characterized by particle size, circularity, fracture strength and their temperature on the exit of extruder. Higher screw speed and lower feed rate were found to help particles agglomerate by allowing feed particles a greater opportunity to increase in temperature. Lower binder molecular weight and higher binder concentration enable granules to build stronger strength and thereby lead to higher particle size. This new twin screw dry granulation was demonstrated as offering advantages over conventional hot melt granulation by minimizing thermal degradation of the tested ingredients. Copyright © 2017 Elsevier B.V. All rights reserved.

Solar heating of air used for the drying at medium and large scale, of forestry, fishery, agriculture, cattle and industrial products

International Nuclear Information System (INIS)

Gutierrez, F.

1991-01-01

The drying process and/or preservation of grains is improved through the previous heating of air. In many cases it is enough to raise the temperature only a few degrees (from 10 to 15 Centigrade), in order to increase their capacity to absorb dampness. This can be done using very simple solar captors. A massive use of solar energy in the drying process of products, by means of hot air, can only be done with very expensive equipment. For this reason, it is recommended the use of lower thermic heaters, which will have a lower cost too. (Author)

A study on the dewatering of industrial waste sludge by fry-drying technology

International Nuclear Information System (INIS)

Ohm, Tae-In; Chae, Jong-Seong; Kim, Jeong-Eun; Kim, Hee-kyum; Moon, Seung-Hyun

2009-01-01

In sludge treatment, drying sludge using typical technology with high water content to a water content of approximately 10% is always difficult because of adhesive characteristics of sludge. Many methods have been applied, including direct and indirect heat drying, but these approaches of reducing water content to below 40% after drying is very inefficient in energy utilization of drying sludge. In this study, fry-drying technology with a high heat transfer coefficient of approximately 500 W/m 2 deg. C was used to dry industrial wastewater sludge. Also waste oil was used in the fry-drying process, and because the oil's boiling point is between 240 and 340 deg. C and the specific heat is approximately 60% of that of water. In the fry-drying system, the sludge is input by molding it into a designated form after heating the waste oil at temperatures between 120 and 170 deg. C. At these temperatures, the heated oil rapidly evaporates the water contained in the sludge, leaving the oil itself. After approximately 10 min, the water content of the sludge was less than 10%, and its heating value surpassed 5300 kcal/kg. Indeed, this makes the organic sludge appropriate for use as a solid fuel. The wastewater sludge used in this study was the designated waste discharged from chemical, leather and plating plants. These samples varied in characteristics, especially with regard to heavy metal concentration. After drying the three kinds of wastewater sludge at oil temperatures 160 deg. C for 10 min, it was found that the water content in the sludge from the chemical, leather, and plating plants reduced from 80.0 to 5.5%, 81.6 to 1.0%, and 65.4 to 0.8%, respectively. Furthermore, the heat values of the sludge from the chemical, leather, and plating plants prior to fry-drying were 217, 264, and 428 kcal/kg, respectively. After drying, these values of sludge increased to 5317, 5983 and 6031 kcal/kg, respectively. The heavy metals detected in the sludge after drying were aluminum

Simulation of exhaust gas heat recovery from a spray dryer

International Nuclear Information System (INIS)

Golman, Boris; Julklang, Wittaya

2014-01-01

This study explored various alternatives in improving the energy utilization of spray drying process through the exhaust gas heat recovery. Extensible and user-friendly simulation code was written in Visual Basic for Applications within Microsoft Excel for this purpose. The effects of process parameters were analyzed on the energy efficiency and energy saving in the industrial-scale spray drying system with exhaust gas heat recovery in an air-to-air heat exchanger and in the system with partial recirculation of exhaust air. The spray dryer is equipped with an indirect heater for heating the drying air. The maximum gains of 16% in energy efficiency and 50% in energy saving were obtained for spray drying system equipped with heat exchanger for exhaust air heat recovery. In addition, 34% in energy efficiency and 61% in energy saving for system with recirculation of exhaust air in the present range of process parameters. The high energy efficiency was obtained during drying of large amount of dilute slurry. The energy saving was increased using the large amount of hot drying air. - Highlights: • We model industrial-scale spray drying process with the exhaust gas heat recovery. • We develop an Excel VBA computer program to simulate spray dryer with heat recovery. • We examine effects of process parameters on energy efficiency and energy saving. • High energy efficiency is obtained during drying of large amount of dilute slurry. • Energy saving is increased using the large amount of hot drying air

Description and cost analysis of a deluge dry/wet cooling system.

Energy Technology Data Exchange (ETDEWEB)

Wiles, L.E.; Bamberger, J.A.; Braun, D.J.; Braun, D.J.; Faletti, D.W.; Willingham, C.E.

1978-06-01

The use of combined dry/wet cooling systems for large base-load power plants offers the potential for significant water savings as compared to evaporatively cooled power plants and significant cost savings in comparison to dry cooled power plants. The results of a detailed engineering and cost study of one type of dry/wet cooling system are described. In the ''deluge'' dry/wet cooling method, a finned-tube heat exchanger is designed to operate in the dry mode up to a given ambient temperature. To avoid the degradation of performance for higher ambient temperatures, water (the delugeate) is distributed over a portion of the heat exchanger surface to enhance the cooling process by evaporation. The deluge system used in this study is termed the HOETERV system. The HOETERV deluge system uses a horizontal-tube, vertical-plate-finned heat exchanger. The delugeate is distributed at the top of the heat exchanger and is allowed to fall by gravity in a thin film on the face of the plate fin. Ammonia is used as the indirect heat transfer medium between the turbine exhaust steam and the ambient air. Steam is condensed by boiling ammonia in a condenser/reboiler. The ammonia is condensed in the heat exchanger by inducing airflow over the plate fins. Various design parameters of the cooling system have been studied to evaluate their impact on the optimum cooling system design and the power-plant/utility-system interface. Annual water availability was the most significant design parameter. Others included site meteorology, heat exchanger configuration and air flow, number and size of towers, fan system design, and turbine operation. It was concluded from this study that the HOETERV deluge system of dry/wet cooling, using ammonia as an intermediate heat transfer medium, offers the potential for significant cost savings compared with all-dry cooling, while achieving substantially reduced water consumption as compared to an evaporatively cooled power plant. (LCL)

Exergoeconomic optimization of an ammonia–water hybrid absorption–compression heat pump for heat supply in a spraydrying facility

DEFF Research Database (Denmark)

Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars

2015-01-01

Spray-drying facilities are among the most energy intensive industrial processes. Using a heat pump to recover waste heat and replace gas combustion has the potential to attain both economic and emissions savings. In the case examined a drying gas of ambient air is heated to 200 C yielding a heat...... load of 6.1 MW. The exhaust air from the drying process is 80 C. The implementation of anammonia–water hybrid absorption–compression heat pump to partly cover the heat load is investigated. A thermodynamic analysis is applied to determine optimal circulation ratios for a number of ammonia mass...... fractions and heat pump loads. An exergo economic optimization is applied to minimize the lifetime cost of the system. Technological limitations are imposed to constrain the solution to commercial components. The best possible implementation is identified in terms of heat load, ammonia mass fraction...

TG-DSC method applied to drying characteristics of areca inflorescence during drying

Science.gov (United States)

Song, Fei; Wang, Hui; Huang, Yulin; Zhang, Yufeng; Chen, Weijun; Zhao, Songlin; Zhang, Ming

2017-10-01

In this study, suitability of eight drying models available in literature on defining drying characteristics of areca inflorescence has been examined by non-linear regression analysis using the Statistic Computer Program. The coefficient of determination ( R 2 ) and the reduced chi-square (χ2) are used as indicators to evaluate the best suitable model. According to the results, the Verma et al. model gave the best results for explaining the drying characteristics of areca inflorescence. The drying process could be divided into three periods: rising rate, constant rate and the falling rate period. Fick's second law can describe the moisture transport during the food drying process that takes place in the falling rate period. The values of effective diffusivity during the drying of areca inflorescence ranged from 2.756 × 10-7 to 6.257 × 10-7 m2/s and the activation energy was tested for 35.535 kJ/mol. The heat requirement of areca inflorescence at 40-60 °C was calculated from 50.57 to 60.50 kJ/kg during the drying process.

The release of organic compounds during biomass drying depends upon the feedstock and/or altering drying heating medium

International Nuclear Information System (INIS)

Rupar, K.; Sanati, M.

2003-01-01

The release of organic compounds during the drying of biomass is a potential environmental problem, it may contribute to air pollution or eutrophication. In many countries there are legal restrictions on the amounts of terpenes that may be released into the atmosphere. When considering bioenergy in future energy systems, it is important that information on the environmental effects is available. The emissions of organic compounds from different green and dried biofuels that have been dried in hot air and steam medium, were analyzed by using different techniques. Gas chromatography and gas chromatography mass spectrometry have been used to identify the organic matter. The terpene content was significantly affected by the following factors: changing of the drying medium and the way the same biomass was handled from different localities in Sweden. Comparison between spectra from dried and green fuels reveal that the main compounds emitted during drying are monoterpene and sesquiterpene hydrocarbons, while the emissions of diterpene hydrocarbons seem to be negligible. The relative proportionality between emitted monoterpene, diterpene and sesquiterpene change when the drying medium shifts from steam to hot air. The obtained result of this work implies a parameter optimization study of the dryer with regard to environmental impact. With assistance of this result it might be foreseen that choice of special drying medium, diversity of biomass and low temperature reduce the emissions. A thermo-gravimetric analyzer was used for investigating the biomass drying rate. (author)

Symbiotic potential: the integration of preheating and dry cooling in cokemaking

Energy Technology Data Exchange (ETDEWEB)

Barker, J E

1978-06-01

In the USSR and Japan, heat recovered from the dry cooling of coke is used to raise steam for power generation or process use. This heat could be used to dry and preheat coal to improve both coke quality and oven productivity.

The thermodynamics of enhanced heat transfer: a model study

International Nuclear Information System (INIS)

Hovhannisyan, Karen; Allahverdyan, Armen E

2010-01-01

Situations where a spontaneous process of energy or matter transfer is enhanced by an external device are widespread in nature (the human sweating system, enzyme catalysis, facilitated diffusion across biomembranes, industrial heat-exchangers and so on). The thermodynamics of such processes remains, however, open. Here we study enhanced heat transfer by using a model junction immersed between two thermal baths at different temperatures T h and T c (T h > T c ). The transferred heat power is enhanced via controlling the junction by means of external time-dependent fields. Provided that the spontaneous heat flow process is optimized over the junction Hamiltonian, any enhancement of this spontaneous process demands consumption and subsequent dissipation of work. The efficiency of the enhancement is defined via the increment in the heat power divided by the amount of work done. We show that this efficiency is bounded from above by T c /(T h − T c ). Formally this is identical to the Carnot bound for the efficiency of ordinary refrigerators which transfer heat from cold to hot bodies. It also shares some (but not all) physical features of the Carnot bound

Critical heat flux, post dry-out and their augmentation

International Nuclear Information System (INIS)

Celata, G.P.; Mariani, A.

1999-01-01

The report shows the state of art review on the critical heat flux and the post-dryout heat transfer. The work, which is a merge of original researches carried out at the Institute of Thermal Fluid Dynamic of ENEA (National Agency for New Technology, Energy and the Environment) and a thorough review of the recent literature, is divided in four chapters: critical heat flux in subcooled flow boiling; critical heat flux in saturated flow boiling; post-dryout heat transfer; enhancement of critical heat flux and post-dryout heat transfer [it

Dry cooling tower operating experience in the LOFT reactor

International Nuclear Information System (INIS)

Hunter, J.A.

1980-01-01

A dry cooling tower has been uniquely utilized to dissipate heat generated in a small experimental pressurized water nuclear reactor. Operational experience revealed that dry cooling towers can be intermittently operated with minimal wind susceptibility and water hammer occurrences by cooling potential steam sources after a reactor scram, by isolating idle tubes from the external atmosphere, and by operating at relatively high pressures. Operating experience has also revealed that tube freezing can be minimized by incorporating the proper heating and heat loss prevention features

Engineering and economic evaluation of wet/dry cooling towers for water conservation

International Nuclear Information System (INIS)

Hu, M.C.

1976-11-01

The results are presented of a design and cost study for wet/dry tower systems used in conjunction with 1000 MWe nuclear power plants to reject waste heat while conserving water. Design and cost information for wet/dry tower systems are presented, and these cooling system alternatives are compared with wet and dry tower systems to determine whether the wet/dry tower concept is an economically viable alternative. The wet/dry cooling tower concept investigated is one which combines physically separated wet towers and dry towers into an operational unit. In designing the wet/dry tower, a dry cooling tower is sized to carry the plant heat load at low ambient temperatures, and a separate wet tower is added to augment the heat rejection of the dry tower at higher ambient temperatures. These wet/dry towers are designed to operate with a conventional low back pressure turbine commercially available today. The component wet and dry towers are state-of-the-art designs. From this study it was concluded that: wet/dry cooling systems can be designed to provide a significant economic advantage over dry cooling yet closely matching the dry tower's ability to conserve water, a wet/dry system which saves as much as 99 percent of the make-up water required by a wet tower can maintain that economic advantage, and therefore, for power plant sites where water is in short supply, wet/dry cooling is the economic choice over dry cooling

DRUM DRYER FOR DRYING THE PARTICULATE PRODUCTS

Directory of Open Access Journals (Sweden)

I. S. Iurova

2014-01-01

Full Text Available Summary. For raise effectiveness drying process drum-type installation in which drum the mechanism of creation of various zones providing a necessary temperature and hydrodynamic regime of process of drying in process of product passage on a drum and changes in it of a relationship of various forms of communication of a moisture, and also a process intensification at last stage of drying by creation разряжения in a continuous technological stream of drying is provided is offered. The drum provides formation of a zone of separation of heat-transfer agent by means of the dissector, zones of intensive drying by disposing lobate nozzles in chessboard order with a dividing ring, zones of separation of the completed heat-transfer agent from жома as a result of separator installation in which the elliptic disk having cuts on a straight line from edge to the centre places, with formation of the triangular slot for passage dried pulp and heat-transfer agent, and also zones the final drying by performance of a section of a drum matching to a zone perforated on which length are had spring-loaded lobate nozzles representing the blades connected bow-shaped rod with metal plates, had with outer side of a drum and under the form repeating its contour, thus the bow-shaped rod from the interior of a drum which ends are supplied by springs rest against overhead and bottom persistent screw nuts, and blades and metal plates are installed with possibility of twirl concerning a fastening place on a drum and supplied by reinforcing ribs.

Splitting the exergy destruction into avoidable and unavoidable parts of a gas engine heat pump (GEHP) for food drying processes based on experimental values

International Nuclear Information System (INIS)

Gungor, Aysegul; Erbay, Zafer; Hepbasli, Arif; Gunerhan, Huseyin

2013-01-01

Highlights: • Advanced exergy analysis of a gas engine heat pump drying system for the first time. • Varying exergy efficiency values from 79.71% to 81.66% for the overall drying system. • Obtaining modified exergy efficiencies of 84.50–86.00% for the overall drying system. - Abstract: Some limitations in a conventional exergy analysis may be significantly reduced through an advanced exergy analysis. In this regard, the latter is a very useful tool to assess the real potential for improving a system component by splitting the exergy destruction into unavoidable and avoidable parts. This may provide a realistic measure to deduct the improvement potential for the thermodynamic efficiency of a component. For this purpose, improvement efforts are then made by focusing only on these avoidable parts. In this paper, a gas engine heat pump (GEHP) drying system was analyzed using both conventional and advanced exergy analyses. Three medicinal and aromatic plants (Foeniculum vulgare, Malva sylvestris L. and Thymus vulgaris) were dried in a pilot scale GEHP drier, which was designed, constructed and installed in Ege University, Izmir, Turkey. Drying experiments were performed at an air temperature of 45 °C with an air velocity of 1 m/s. For each system component, avoidable and unavoidable exergy destructions, modified exergy efficiency values and modified exergy destruction ratios were determined. Except for the compressor, the evaporator and the drying cabinet, most of the exergy destructions in the system components were avoidable and these avoidable parts can be reduced by design improvements. For the HP unit and the overall drying system, the values for exergy efficiency were obtained to be in the range of 82.51–85.11% and 79.71–81.66% while those for the modified exergy efficiency were calculated to be in the range of 85.70–89.26% and 84.50–86.00%, respectively

Heat stress proteins in hypertension

International Nuclear Information System (INIS)

Malo, D.; Tremblay, J.; Pang, S.C.; Schlager, G.; Hamet, P.

1986-01-01

It has been described that spontaneously hypertensive rats (SHR) are more sensitive to an acute environmental heat stress and that cultured cardiomyocytes from neonatal SHR are demonstrated to be more thermosensitive. In addition, chronically heat exposed spontaneously hypertensive mice leads to a decrease of blood pressure in these animals. Heat shock is known to induce the synthesis of a new set of proteins (HSP) in every cell tested. This ubiquitous response seems to be involved in the induction of a thermotolerant state. The synthesis of 70K HSP was observed in lymphocytes isolated from the spleen of chronically heated mice. They used lymphocytes, previously isolated on a ficoll gradient, to evaluate the HSP induction in normotensive (WKY) and hypertensive (SHR) rats. The heat shock was induced by exposing the lymphocytes at 46 0 C during 5 min in a hot water bath. The cells were then labeled with ( 75 Se)-methionine, washed, homogenized and separated on 5-30% SDS-polyacrylamide gel. Preliminary results suggest an abnormal pattern of induction of 70K and 90K HSP in hypertension. Heat sensitivity, thermotolerance and expression of HSP may, thus, be related to hypertension

The Effect of Contact Angle on Dynamics of Dry Spots Spreading in a Horizontal Layer of Liquid at Local Heating

Directory of Open Access Journals (Sweden)

Zaitsev D.V.

2015-01-01

Full Text Available The effect of equilibrium contact angle on dynamics of dry spot spreading at disruption of a horizontal water layer heated locally from the substrate was studied using the high-speed Schlieren technique. Different methods of working surface processing were applied; this allowed variations of the equilibrium contact angle from 27±6° to 74±9° without a change in thermal properties of the system. It is found out that substrate wettability significantly affects the propagation velocity of dry spot and its final size. It is also found out that the velocity of contact line propagation is higher in the areas of substrate with a higher temperature.

Rehydration ratio of fluid bed-dried vegetables

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

In the food processing industry the heat treatment of vegetables is a very important ... preparation is very important for the best drying results, while the drying times are more or ... C for 3 minutes, cooked for 15 minutes in water and then.

CFD simulation of a dry scroll vacuum pump with clearances, solid heating and thermal deformation

Science.gov (United States)

Spille-Kohoff, A.; Hesse, J.; Andres, R.; Hetze, F.

2017-08-01

Although dry scroll vacuum pumps (DSPV) are essential devices in many different industrial processes, the CFD simulation of such pumps is not widely used and often restricted to simplified cases due to its complexity: The working principle with a fixed and an orbiting scroll leads to working chambers that are changing in time and are connected through moving small radial and axial clearances in the range of 10 to 100 μm. Due to the low densities and low mass flow rates in vacuum pumps, it is important to include heat transfer towards and inside the solid components. Solid heating is very slow compared to the scroll revolution speed and the gas behaviour, thus a special workflow is necessary to reach the working conditions in reasonable simulation times. The resulting solid temperature is then used to compute the thermal deformation, which usually results in gap size changes that influence leakage flows. In this paper, setup steps and results for the simulation of a DSVP are shown and compared to theoretical and experimental results. The time-varying working chambers are meshed with TwinMesh, a hexahedral meshing programme for positive displacement machines. The CFD simulation with ANSYS CFX accounts for gas flow with compressibility and turbulence effects, conjugate heat transfer between gas and solids, and leakage flows through the clearances. Time-resolved results for torques, chamber pressure, mass flow, and heat flow between gas and solids are shown, as well as time- and space-resolved results for pressure, velocity, and temperature for different operating conditions of the DSVP.

PULSE DRYING EXPERIMENT AND BURNER CONSTRUCTION

Energy Technology Data Exchange (ETDEWEB)

Robert States

2006-07-15

Non steady impingement heat transfer is measured. Impingement heating consumes 130 T-BTU/Yr in paper drying, but is only 25% thermally efficient. Pulse impingement is experimentally shown to enhance heat transfer by 2.8, and may deliver thermal efficiencies near 85%. Experimental results uncovered heat transfer deviations from steady theory and from previous investigators, indicating the need for further study and a better theoretical framework. The pulse burner is described, and its roll in pulse impingement is analyzed.

Usage of hybrid solar collector system in drying technologies of medical plants

International Nuclear Information System (INIS)

Čiplienė, Aušra; Novošinskas, Henrikas; Raila, Algirdas; Zvicevičius, Egidijus

2015-01-01

Highlights: • Solar radiation energy utilization in drying technologies. • Accumulation of solar radiation energy. • The system comprising two different solar collector types. • Preparation of the drying agent by employing solar radiation energy around the clock. • The energy resources saving technology for medicinal plants’ raw material processing and drying. - Abstract: In the temperate climate zone under natural conditions, medicinal plants drying up to 8–12% moisture content and preparation of the quality medicinal plant’s raw material are complicated tasks. In many cases drying process of medicinal plants raw material, particularly rich in volatile compounds, needs the optimal drying temperatures of 30–45 °C and relative humidity not higher than 50–60%. In Lithuania, located in the northern part of the temperate climate zone, in summer the average temperature of ambient air is 16.1 ± 0.5 °C, and relative humidity is 77.3 ± 1.8%. In order to improve the sorption properties of ambient air, it is heated up to the admissible drying temperature. The experimental dryer was developed comprising two different solar collectors: the air type solar collector with area 12 m 2 for direct heating of the drying agent and the flat-plate type solar collector (8 m 2 ) for accumulation of converted heat energy. The research of motherwort (Leonurus cardiaca L.) drying was carried out in the dryer. It was determined that by combining operation of two different solar collectors, the solar radiation energy for drying agent’s heating could be used continuously around the clock by employing the accumulated energy, in order to compensate the solar irradiance variability and to ensure stability of the drying process. In the daytime the air-type solar collector at an airflow equal to 367 m 3 h −1 , i.e. at comparative flow of the drying agent per ton of dried medicinal plant raw material – 2450 m 3 h −1 , heats the air up to 30 °C when the solar

Spontaneous Rayleigh-Brillouin scattering of ultraviolet light in nitrogen, dry air and moist air,

NARCIS (Netherlands)

Witschas, B.; Vieitez, M.O.; Duijn, van E.-J.; Reitebuch, O.; Water, van de W.; Ubachs, W.

2010-01-01

Atmospheric lidar techniques for the measurement of wind, temperature, and optical properties of aerosols rely on the exact knowledge of the spectral line shape of the scattered laser light on molecules. We report on spontaneous Rayleigh–Brillouin scattering measurements in the ultraviolet at a

Turbulence and heat transfer in condensate in drying cylinders at high g-forces. Phase 1; Turbulens och vaermeoeverfoering i kondensat i torkcylindrar vid hoega g-krafter. Fas 1

Energy Technology Data Exchange (ETDEWEB)

Stenstroem, Stig; Ingvarsson, David [Lund Inst. of Tech. (Sweden). Dept. of Chemical Engineering

2005-09-01

Drying of paper is performed by bringing the paper into contact with a hot cylinder surface so that the water in the web is evaporated. The energy needed to heat the drying cylinder is supplied with condensing steam creating a condensate layer on the inside surface of the cylinder. For fast paper machines, the condensate layer will be close to stagnant, thus constituting a significant resistance for the heat transfer process from the steam to the paper. The traditional technique to improve the heat transfer has been to install turbulence bars on the inside surface of the cylinder but at machine speeds of up to 2000 m/min this technique is not sufficiently efficient. The goal in the project has been to study the condensate behaviour in drying cylinders at high centrifugal forces and explore different methods to improve the heat transfer in the condensate for both new and existing fast paper machines so that the capacity in the dryer section can be maintained at a high level. The results are of importance for the manufacturers of paper machines as well as the producing newsprint and printing paper companies. The project has been divided in the following parts: - Literature survey of techniques to increase the heat transfer in condensate and the removal of condensate with siphons. - Develop knowledge about the condensate behaviour in rotating cylinders at high g-forces with and without spoiler bars. This has been accomplished by designing a new cylinder where the condensate velocity relative to the cylinder could be measured at centrifugal forces corresponding to the levels today reached at fast paper machines. Such data have previously not been reported in the literature. - Present solutions for the design of the inside surface of the drying cylinder so that high heat transfer rates can be accomplished in fast paper machines. Solutions should be presented both for existing as well as new paper machines. The results in the project show that at centrifugal forces of

Determination of the dried product resistance variability and its influence on the product temperature in pharmaceutical freeze-drying.

Science.gov (United States)

Scutellà, Bernadette; Trelea, Ioan Cristian; Bourlès, Erwan; Fonseca, Fernanda; Passot, Stephanie

2018-07-01

During the primary drying step of the freeze-drying process, mass transfer resistance strongly affects the product temperature, and consequently the final product quality. The main objective of this study was to evaluate the variability of the mass transfer resistance resulting from the dried product layer (R p ) in a manufacturing batch of vials, and its potential effect on the product temperature, from data obtained in a pilot scale freeze-dryer. Sublimation experiments were run at -25 °C and 10 Pa using two different freezing protocols: with spontaneous or controlled ice nucleation. Five repetitions of each condition were performed. Global (pressure rise test) and local (gravimetric) methods were applied as complementary approaches to estimate R p . The global method allowed to assess variability of the evolution of R p with the dried layer thickness between different experiments whereas the local method informed about R p variability at a fixed time within the vial batch. A product temperature variability of approximately ±4.4 °C was defined for a product dried layer thickness of 5 mm. The present approach can be used to estimate the risk of failure of the process due to mass transfer variability when designing freeze-drying cycle. Copyright © 2018 Elsevier B.V. All rights reserved.

Bacterial and Fungal Counts of Dried and Semi-Dried Foods Collected from Dhaka, Bangladesh, and Their Reduction Methods.

Science.gov (United States)

Feroz, Farahnaaz; Shimizu, Hiromi; Nishioka, Terumi; Mori, Miho; Sakagami, Yoshikazu

2016-01-01

　Food is a basic necessity for human survival, but it is still the vehicle for the transmission of food borne disease. Various studies have examined the roles of spices, herbs, nuts, and semi-dried fruits, making the need for safe and convenient methods of decontamination a necessity. The current study determined the bacterial and fungal loads of 26 spices and herbs, 5 nuts, 10 semi-dried fruits and 5 other foods. Spices, herbs and semi-dried foods demonstrated the highest bacterial and fungal loads with the majority showing over 10 4 CFU/mL. Nuts and other foods showed growths ranging from 10 2 to 10 6 CFU/mL. The current study also attempted to determine the effects of heat and plasma treatment. The log reduction of bacterial growth after heat treatment (maximum: 120 min for 60℃) was between 0.08 to 4.47, and the log reduction after plasma treatment (maximum: 40 min) ranged from 2.37 to 5.75. Spices showed the lowest rates of reduction, whereas the semi-dried and other foods showed moderate to high levels of decrease after heat treatment. The log reduction of fungal growth after heat treatment ranged from 0.27 to 4.40, and log reduction after plasma treatment ranged from 2.15 to 5.91．Furthermore, we validated the sterilization effect of plasma treatment against Bacillus spp. and Staphylococcus spp. by using scanning electron microscopy. Both treatment methods could prove to be advantageous in the agriculture related fields, enhancing the quality of the foods.

Development and demonstration of calculation tool for industrial drying processes ''DryPack''; Udvikling og demonstration af beregningsvaerktoej til industrielle toerreprocesser ''DryPack''

Energy Technology Data Exchange (ETDEWEB)

Schneider, P.; Weinkauff Kristoffersen, J.; Blazniak Andreasen, M. [Teknologisk Institut, Aarhus (Denmark); Elmegaard, B.; Kaern, M. [Danmarks Tekniske Univ.. DTU Mekanik, Kgs. Lyngby (Denmark); Monrad Andersen, C. [Lokal Energi, Viby J. (Denmark); Grony, K. [SE Big Blue, Kolding (Denmark); Stihoej, A. [Enervision, Kolding (Denmark)

2013-03-15

In this project we have developed a calculation tool for calculating energy consumption in different drying processes - primarily drying processes with air. The program can be used to determine the energy consumption of a current drying process, after which it can be calculated how much energy can be saved by various measures. There is also developed a tool for the simulation of a batch drier, which calculates the drying of a batch depending on the time. The programs have demonstrated their usefulness in connection with three cases that are reviewed in the report. In the project measurements on four different dryers have been carried out, and energy consumption is calculated using ''DryPack''. With ''DryPack'' it is possible to find potential savings by optimizing the drying processes. The program package includes utilities for the calculation of moist air: 1) Calculation of the thermodynamic properties of moist air; 2) Device operation with moist air (mixing, heating, cooling and humidification); 3) Calculation of the relative change of the drying time by changing the process parameters; 4) IX-diagram at a temperature above 100 deg. C. (LN)

Design of dry cask storage for Serpong multi purpose reactor spent nuclear fuel

International Nuclear Information System (INIS)

Dyah Sulistyani Rahayu; Yuli Purwanto; Zainus Salimin

2018-01-01

The spent nuclear fuel (SNF) from Serpong Multipurpose Reactor, after 100 days storing in the reactor pond, is transferred to water pool interim storage for spent fuel (ISFSF). At present there are a remaining of 245 elements of SNF on the ISSF, 198 element of which have been re-exported to the USA. The dry-cask storage allows the SNF, which has already been cooled in the ISSF, to lower its radiation exposure and heat decay at a very low level. Design of the dry cask storage for SNF has been done. Dual purpose of unventilated vertical dry cask was selected among other choices of metal cask, horizontal concrete modules, and modular vaults by taking into account of technical and economical advantages. The designed structure of cask consists of SNF rack canister, inner steel liner, concrete shielding of cask, and outer steel liner. To avoid bimetallic corrosion, the construction material for canister and inner steel liner follows the same material construction of fuel cladding, i.e. the alloy of AlMg 2 . The construction material of outer steel liner is copper to facilitate the heat transfer from the cask to the atmosphere. The total decay heat is transferred from SNF elements bundle to the atmosphere by a serial of heat transfer resistance for canister wall, inner steel liner, concrete shielding, and outer steel liner respectedly. The rack canister optimum capacity of 34 fuel elements was designed by geometric similarity method based on SNF position arrangement of 7 x 6 triangular pitch array of fuel elements for prohibiting criticality by spontaneous neutron. The SNF elements are stored vertically on the rack canister. The thickness of concrete wall shielding was calculated by trial and error to give air temperature of 30 °C and radiation dose on the wall surface of outer liner of 200 mrem/h. The SNF elements bundles originate from the existing racks of wet storage, i.e. rack canister no 3, 8 and 10. The value of I 0 from the rack no 3, 8 and 10 are 434.307; 446

Turbulence and heat transfer in condensate in drying cylinders at high g-forces. Phase 2; Turbulens och vaermeoeverfoering i kondensat i torkcylindrar vid hoega g-krafter. Fas 2

Energy Technology Data Exchange (ETDEWEB)

Stenstroem, Stig; Ingvarsson, David [Lund Inst. of Tech. (Sweden). Dept. of Chemical Engineering

2006-02-15

During paper drying a condensate layer is formed on the inside surface of the rotating cylinder which acts as resistance for heat transfer through the cylinder. The heat transfer resistance in the condensate layer is mainly dependant on the layer thickness and the turbulence in the layer. Consequently the resistance increases with higher cylinder speeds due to increased centrifugal forces and thus reduced turbulence in the layer. In order to minimize the influence of condensate on the heat transfer process the cylinder used in Phase 1 has been equipped with axial grooves. The aim of the project has been to study the water movement in the cylinder and to investigate how the drying capacity is influenced by condensate accumulating in the grooves rather than moving along the smooth surface of a paper dryer cylinder. This knowledge should be considered preferably before construction of cylinders for new machines. For existing machines with smooth cylinders the importance of axial vertical flanges for improved heat transfer has been investigated. In addition the capacity of stationary siphons has been evaluated. The results are of importance for the manufacturers of paper machines as well as the producing newsprint and printing paper companies. According to the results from the experiments the water flows mainly in the grooves, assuming that the number of grooves and that the dimensions of the grooves are adjusted to the water load. Then the surfaces between the grooves can be considered as completely dry unlike in a smooth cylinder where the surfaces more or less are covered with a thin layer of condensate. Furthermore the centrifugal force helps the water to flow down into the grooves. Consequently a high water flow will rely on a high cylinder speed in order to keep the water flowing into the axial grooves. The computer simulations show that the drying capacity increases with up to 46 % in dryer cylinders provided with axial grooves compared to smooth cylinders

Experimental Investigation of Solar Drying for Orange Peels by Forced convection

International Nuclear Information System (INIS)

Ben Slama, Romdhane; Mechlouch, Fethi; Ben Daoud, Houcine

2009-01-01

Solar drier does not degrade any more the dried products with the manner of the products dried at the natural sun. The drying unit is composed mainly of a solar air collector and an enclosure of drying. The transformation of the solar radiation into heat is done thanks to the solar collector whose effectiveness is increased by the addition of suitable baffles in the mobile air vein. The efficiency of the collector reaches then 80. The hot air on the outlet side of the collector arrives in the enclosure of drying where the heat transfer with the product to be dried is done by convection. The kinetics drying study shows that in addition to the dependence of the temperature and air velocity of drying, the speed of drying also depends on fragmentation on the product to dry, and mainly, of the product surface in contact with the drying air. Thus, the hygrometry is reduced from 76 to 13 pour cent in one day.. The total efficiency of the drier reached 28 pour cent

Computer optimization of dry and wet/dry cooling tower systems for large fossil and nuclear power plants

International Nuclear Information System (INIS)

Choi, M.; Glicksman, L.R.

1979-02-01

This study determined the cost of dry cooling compared to the conventional cooling methods. Also, the savings by using wet/dry instead of all-dry cooling were determined. A total optimization was performed for power plants with dry cooling tower systems using metal-finned-tube heat exchangers and surface condensers. The optimization minimizes the power production cost. The program optimizes the design of the heat exchanger and its air and water flow rates. In the base case study, the method of replacing lost capacity assumes the use of gas turbines. As a result of using dry cooling towers in an 800 MWe fossil plant, the incremental costs with the use of high back pressure turbine and conventional turbine over all-wet cooling are 11 and 15%, respectively. For a 1200 MWe nuclear plant, these are 22 and 25%, respectively. Since the method of making up lost capacity depends on the situation of a utility, considerable effort has been placed on testing the effects of using different methods of replacing lost capacity at high ambient temperatures by purchased energy. The results indicate that the optimization is very sensitive to the method of making up lost capacity. It is, therefore, important to do an accurate representation of all possible methods of making up capacity loss when optimizating power plants with dry cooling towers. A solution for the problem of losing generation capability by a power plant due to the use of a dry cooling tower is to supplement the dry tower during the hours of peak ambient temperatures by a wet tower. A separate wet/dry cooling tower system with series tower arrangement was considered in this study, and proved to be an economic choice over all-dry cooling where some water is available but supplies are insufficient for a totally evaporative cooling tower

Hydrophobicity of stored (15, 35 °C), or dry-heated (120 °C) rice flour and deteriorated breadmaking properties baked with these treated rice flour/fresh gluten flour.

Science.gov (United States)

Nakagawa, Mariko; Tabara, Aya; Ushijima, Yuki; Matsunaga, Kotaro; Seguchi, Masaharu

2016-05-01

Rice flour was stored at 15 °C/9 months, at 35 °C/14 days, or dry-heated at 120 °C/20 min. The breadmaking properties baked with this rice flour/fresh gluten flour deteriorated. In addition, the rice flour was mixed with oil in water vigorously, and oil-binding ability was measured. Every rice flour subjected to storage or dry-heated at 120 °C showed higher hydrophobicity, owing to changes in proteins. Then, proteins in the stored rice flour were excluded with NaOH solution, and bread baked with the deproteinized rice flour showed the same breadmaking properties as unstored rice flour/fresh gluten flour. The viscoelasticity of wheat glutenin fraction decreased after the addition of dry-heated rice flour in a mixograph profile. DDD staining increased Lab in color meter, which suggested an increase in SH groups in rice protein. The increase in SH groups caused a reduction in wheat gluten protein resulting in a deterioration of rice bread quality.　.

Inquiry on the valorisation of heat produced by methanization with co-generation in France. Energy and territory: Valorisation of heat produced by methanization

International Nuclear Information System (INIS)

Bazin, Florian; David, Laura; Heuraux, Thalie; Jeziorny, Thibaud; Massazza, Michael; Mosse, Noemie; Nguyen Dai, Kim Yen; Pruvost, Paul; Regimbart, Amelie; Rogee, Pierre-Emmanuel; Roy, Samuel; Segret, Emilien

2014-01-01

A leaflet first proposes graphs which illustrate the valorisation of heat produced by methanization with co-generation in France: material and methods, farm characterisation, plant sources, valorisation modes. The second document proposes detailed and discussed presentations of the various involved processes. Contributions address methanization as a whole, valorisation of heat produced by co-generation through heating of agricultural and domestic buildings or through digestate dehydration, digestate hygienisation, and other types of valorisation such as fodder drying, cereal drying, wood drying, compost drying, fabrication of rape seed, greenhouse crops, cultures of micro algae, and mushroom farming

Critical heat flux, post dry-out and their augmentation

Energy Technology Data Exchange (ETDEWEB)

Celata, G.P.; Mariani, A. [ENEA, Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy). Dipt. Energia

1999-07-01

The report shows the state of art review on the critical heat flux and the post-dryout heat transfer. The work, which is a merge of original researches carried out at the Institute of Thermal Fluid Dynamic of ENEA (National Agency for New Technology, Energy and the Environment) and a thorough review of the recent literature, is divided in four chapters: critical heat flux in subcooled flow boiling; critical heat flux in saturated flow boiling; post-dryout heat transfer; enhancement of critical heat flux and post-dryout heat transfer. [Italian] Si passa in rassegna lo stato dell'arte sulla crisi termica e sullo scambio termico post-crisi, che compendia studi tradizionali condotti dall'ENEA. Il rapporto e' suddiviso in quattro parti: crisi termica in ebollizione sottoraffreddata; crisi termica in ebollizione satura; scambio termico dopo la crisi termica; incremento del flusso termico critico e dello scambio termico post-crisi.

Critical heat flux, post dry-out and their augmentation

Energy Technology Data Exchange (ETDEWEB)

Celata, G P; Mariani, A [ENEA, Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy). Dipt. Energia

1999-07-01

The report shows the state of art review on the critical heat flux and the post-dryout heat transfer. The work, which is a merge of original researches carried out at the Institute of Thermal Fluid Dynamic of ENEA (National Agency for New Technology, Energy and the Environment) and a thorough review of the recent literature, is divided in four chapters: critical heat flux in subcooled flow boiling; critical heat flux in saturated flow boiling; post-dryout heat transfer; enhancement of critical heat flux and post-dryout heat transfer. [Italian] Si passa in rassegna lo stato dell'arte sulla crisi termica e sullo scambio termico post-crisi, che compendia studi tradizionali condotti dall'ENEA. Il rapporto e' suddiviso in quattro parti: crisi termica in ebollizione sottoraffreddata; crisi termica in ebollizione satura; scambio termico dopo la crisi termica; incremento del flusso termico critico e dello scambio termico post-crisi.

Spontaneous ignition of wood, char and RDF in a lab scale packed bed

NARCIS (Netherlands)

Blijderveen, M.; Gucho, Eyerusalem Merin; Gucho, Eyerusalem M.; Bramer, Eduard A.; Brem, Gerrit

2010-01-01

Many municipal waste combustors use preheated primary air in the first zone to dry the waste. In most cases the preheat temperature does not exceed 140 °C. In previous experiments it is found that at temperatures around 200 °C, in some circumstances, self- or spontaneous ignition can be achieved.

Design of a dry cask storage system for spent LWR fuels: radiation protection, subcriticality, and heat removal aspects

Energy Technology Data Exchange (ETDEWEB)

Yavuz, U. [Turkish Atomic Energy Authority, Ankara (Turkey). Nuclear Safety Dept.; Zabunoolu, O.H. [Hacettepe Univ., Ankara (Turkey). Dept. of Nuclear Engineering

2006-08-15

Spent nuclear fuel resulting from reactor operation must be safely stored and managed prior to reprocessing and/or final disposal of high-level waste. Any spent fuel storage system must provide for safe receipt, handling, retrieval, and storage of spent fuel. In order to achieve the safe storage, the design should primarily provide for radiation protection, subcriticality of spent fuel, and removal of spent fuel residual heat. This article is focused on the design of a metal-shielded dry-cask storage system, which will host spent LWR fuels burned to 33 000, 45 000, and 55 000 MWd/t U and cooled for 5 or 10 years after discharge from reactor. The storage system is analyzed by taking into account radiation protection, subcriticality, and heat-removal aspects; and appropriate designs, in accordance with the international standards. (orig.)

The decrease in the IgG-binding capacity of intensively dry heated whey proteins is associatead with intense Maillard reaction, structural changes of the proteins and formation of RAGE-ligands

NARCIS (Netherlands)

Liu, F.; Teodorowicz, M.; Boekel, van M.A.J.S.; Wichers, H.J.; Hettinga, K.A.

2016-01-01

Heat treatment is the most common way of milk processing, inducing structural changes as well as chemical modifications in milk proteins. These modifications influence the immune-reactivity and allergenicity of milk proteins. This study shows the influence of dry heating on the solubility, particle

Thermalhydraulic behavior of electrically heated rods during critical heat flux transients

International Nuclear Information System (INIS)

Lima, Rita de Cassia Fernandes de

1997-01-01

In nuclear reactors, the occurrence of critical heat flux leads to fuel rod overheating with clad fusion and radioactive products leakage. To predict the effects of such phenomenon, experiments are performed utilizing heated rods to simulate operational and accidental conditions of nuclear fuel rods, with special attention to the phenomenon of boiling crisis. The use of mechanisms which detect the abrupt temperature rise allows the electric power switch off. These facts prevent the test section from damage. During the critical heat flux phenomenon the axial heat conduction becomes very important. The study of the dryout and rewetting fronts yields the analysis, planning and following of critical heat flux experiments. These facts are important during the reflooding of nuclear cores at severe accidents. In the present work it is performed a theoretical analysis of the drying and rewetting front propagation during a critical heat flux experiment, starting with the application of an electrical power step or power slope from steady state condition. After the occurrence of critical heat flux, it is predicted the drying front propagation. After a few seconds, a power cut is considered and the rewetting front behavior is analytically observed. In all these transients the coolant pressure is 13,5 MPa. For one of them, comparisons are done with a pressure of 8,00 MPa. Mass flow and enthalpy influences on the fronts velocities are also analysed. These results show that mass flow has more importance on the drying front velocities whereas the pressure alters strongly the rewetting ones. (author)

Dynamics of acoustic-convective drying of sunflower cake

Science.gov (United States)

Zhilin, A. A.

2017-10-01

The dynamics of drying sunflower cake by a new acoustic-convective method has been studied. Unlike the conventional (thermal-convective) method, the proposed method allows moisture to be extracted from porous materials without applying heat to the sample to be dried. Kinetic curves of drying by the thermal-convective and acoustic-convective methods were obtained and analyzed. The advantages of the acoustic-convective extraction of moisture over the thermal-convective method are discussed. The relaxation times of drying were determined for both drying methods. An intermittent drying mode which improves the efficiency of acoustic-convective extraction of moisture is considered.

Water flow and energy balance for a tropical dry semideciduous forest

Science.gov (United States)

Andrade, J. L.; Garruña-Hernandez, R.; Leon-Palomo, M.; Us-Santamaria, R.; Sima, J. L.

2013-05-01

Tropical forests cool down locally because increase water evaporation from the soil to the atmosphere, reduce albedo and help forming clouds that reflect solar radiation back to the atmosphere; this, aligned to the carbon catchment, increase forests value. We will present an estimation of the sap flow and energy balance for the tropical dry semideciduous forest at Kiuic, Yucatan, Mexico during a year. We use a meteorological tower equipped with a rain gauge, temperature and relative humidity, heat flow plates, thermocouples and volumetric soil water content. We recorded net radiation and soil heat flux and estimated sensible heat and latent heat. Besides, we estimated latent heat by measuring sap flow directly in tres using disispation constant heat probes during the rainy season. Results show the influence of the seasonality on net radiation, air temperatura and vapor pressure deficit, because during the dry season his variables were higher and with more duation than during the rainy and early dry season. Sap flow was different for trees belonging to the family Fabaceae compared to trees from other families.

An economic optimization of evaporator and air collector area in a solar assisted heat pump drying system

International Nuclear Information System (INIS)

Rahman, S.M.A.; Saidur, R.; Hawlader, M.N.A.

2013-01-01

Highlights: • The optimum combination will provide around 89% of the total load. • The system has a savings during the life cycle with least payback period of 4.37 year. • The optimal system is insensitive to the variation in fuel inflation and discount rate. - Abstract: This paper presents an economic optimization of evaporator and air collector area of a solar assisted heat pump drying system. Economic viability of solar heating systems is usually made by comparing the cost flows recurring throughout the lifetime of the solar and conventional alternative systems. Therefore, identification of optimum variables by using a simulation program and an economic analysis based on payback period of the system are presented in this paper. FORTRAN language is used to run the simulation. Effect of load and different economic variables on payback period is also investigated. Economic analysis reveals that system has sufficient amount of savings during the life cycle with a minimum payback period of about 4 years

Heat Damaged Forages: Effects on Forage Quality

Science.gov (United States)

Traditionally, heat damage in forages has been associated with alterations in forage protein quality as a result of Maillard reactions, and most producers and nutritionists are familiar with this concept. However, this is not necessarily the most important negative consequence of spontaneous heating...

Recent advances in fluidized bed drying

Science.gov (United States)

Haron, N. S.; Zakaria, J. H.; Mohideen Batcha, M. F.

2017-09-01

Fluidized bed drying are very well known to yield high heat and mass transfer and hence adopted to many industrial drying processes particularly agricultural products. In this paper, recent advances in fluidized bed drying were reviewed and focus is given to the drying related to the usage of Computational Fluid Dynamics (CFD). It can be seen that usage of modern computational tools such as CFD helps to optimize the fluidized bed dryer design and operation for lower energy consumption and thus better thermal efficiency. Among agricultural products that were reviewed in this paper were oil palm frond, wheat grains, olive pomace, coconut, pepper corn and millet.

Improved energy efficiency in sawmill drying system

International Nuclear Information System (INIS)

Anderson, Jan-Olof; Westerlund, Lars

2014-01-01

Highlights: • A heating system at a sawmill was investigated and improved. • Different impacts of external technologies at the energy usage were explored. • The heat and electricity consumption was analysed separate between technologies type. • The result point out a significant decrease of the biomass consumptions. - Abstract: The worldwide use of biomass has increased drastically during the last decade. At Swedish sawmills about half of the entering timber becomes lumber, with the remainder considered as by-product (biomass). A significant part of this biomass is used for internal heat production, mainly for forced drying of lumber in drying kilns. Large heat losses in kilns arise due to difficulties in recovering evaporative heat in moist air at low temperatures. This paper addresses the impact of available state-of-the-art technologies of heat recycling on the most common drying schemes used in Swedish sawmills. Simulations of different technologies were performed on an hourly basis to compare the heat and electricity demand with the different technologies. This was executed for a total sawmill and finally to the national level to assess the potential effects upon energy efficiency and biomass consumption. Since some techniques produce a surplus of heat the comparison has to include the whole sawmill. The impact on a national level shows the potential of the different investigated techniques. The results show that if air heat exchangers were introduced across all sawmills in Sweden, the heat demand would decrease by 0.3 TWh/year. The mechanical heat pump technology would decrease the heat demand by 5.6 TWh/year and would also produce a surplus for external heat sinks, though electricity demand would increase by 1 TWh/year. The open absorption system decreases the heat demand by 3.4 TWh/year on a national level, though at the same time there is a moderate increase in electricity demand of 0.05 TWh/year. Introducing actual energy prices in Sweden gives an

Improved energy efficiency in juice production through waste heat recycling

International Nuclear Information System (INIS)

Anderson, J.-O.; Elfgren, E.; Westerlund, L.

2014-01-01

Highlights: • A heating system at a juice production was investigated and improved. • Different impacts of drying cycle improvements at the energy usage were explored. • The total heat use for drying could thereby be decreased with 52%. • The results point out a significant decrease of heat consumption with low investment costs. - Abstract: Berry juice concentrate is produced by pressing berries and heating up the juice. The by-products are berry skins and seeds in a press cake. Traditionally, these by-products have been composted, but due to their valuable nutrients, it could be profitable to sell them instead. The skins and seeds need to be separated and dried to a moisture content of less than 10 %wt (on dry basis) in order to avoid fermentation. A berry juice plant in the north of Sweden has been studied in order to increase the energy and resource efficiency, with special focus on the drying system. This was done by means of process integration with mass and energy balance, theory from thermodynamics and psychrometry along with measurements of the juice plant. Our study indicates that the drying system could be operated at full capacity without any external heat supply using waste heat supplied from the juice plant. This would be achieved by increasing the efficiency of the dryer by recirculation of the drying air and by heat supply from the flue gases of the industrial boiler. The recirculation would decrease the need of heat in the dryer with about 52%. The total heat use for the plant could thereby be decreased from 1262 kW to 1145 kW. The improvements could be done without compromising the production quality

Foam-mat drying technology: A review.

Science.gov (United States)

Hardy, Z; Jideani, V A

2017-08-13

This article reviews various aspects of foam-mat drying such as foam-mat drying processing technique, main additives used for foam-mat drying, foam-mat drying of liquid and solid foods, quality characteristics of foam-mat dried foods, and economic and technical benefits for employing foam-mat drying. Foam-mat drying process is an alternative method that allows the removal of water from liquid materials and pureed materials. In this drying process, a liquid material is converted into foam that is stable by being whipped after adding an edible foaming agent. The stable foam is then spread out in sheet or mat and dried by using hot air (40-90°C) at atmospheric pressure. Methyl cellulose (0.25-2%), egg white (3-20%), maltodextrin (0.5-05%), and gum Arabic (2-9%) are the commonly utilized additives for the foam-mat drying process at the given range, either combined together for their effectiveness or individual effect. The foam-mat drying process is suitable for heat sensitive, viscous, and sticky products that cannot be dried using other forms of drying methods such as spray drying because of the state of product. More interest has developed for foam-mat drying because of the simplicity, cost effectiveness, high speed drying, and improved product quality it provides.

Microwave processing heats up

Science.gov (United States)

Microwaves are a common appliance in many households. In the United States microwave heating is the third most popular domestic heating method food foods. Microwave heating is also a commercial food processing technology that has been applied for cooking, drying, and tempering foods. It's use in ...

Better lumber drying process with a non-greenhouse type solar kiln

Energy Technology Data Exchange (ETDEWEB)

Yang, K C

1979-01-01

The preliminary study of using solar energy for lumber drying in NW Ontario is proven applicable and practical by the evidence of data collected. It was found that lumber seasoning using solar energy in the region is more favorable in the summer than in the winter. The most significant advantages of lumber drying with a solar kiln are: (1) low percentage of drying defect lumber produced; (2) higher strength properties of lumber produced; (3) unlimited sources of heat energy from the sun are available. The longer drying periods with a solar kiln as compared to a conventional steam kiln can be overcome by utilizing a supplemental heat system, e.g., wood residue burner to shorten the drying period. However, some improvements and modification of the existing kiln should be done in order to increase the efficiency of the lumber drying system.

Intensifying drying process with creation of functional plant compositions

Directory of Open Access Journals (Sweden)

Zh. Petrova

2015-05-01

Full Text Available Introduction. The process of drying agricultural raw products is associated with loss of bioactive substances by the products exposed to heat, light, oxygen, or рН medium. It is reasonable to enhance the table beet processing technology in order to achieve maximum betanin conservation at lower energy consumption. Materials and methods. Table beets, rhubarbs, lemons, and tomatoes were dried at temperature of 50 to 100 ºС, air speed of 1.5 to 3.5 m/s, heat carrier water content of 7 to 15 g/kg, and layer thickness of 2 to 20 mm. The betanіn content was determined via absorption spectra, using the optical density value at 540 nm wavelength. A differential microcalorimeter was used for measuring evaporation heat consumption. Results and discussion.The effect of raw product pre-drying preparation was studied. With no preliminary preparation, the loss of betanin after drying reaches 66 %. The preliminary preparation technology we have developed includes boiling whole root crops with optimal selection of acid medium and allows us to reduce the betanin loss down to 6 %. Regretfully, the process requires large energy consumption. Low energy consumption pre-drying preparation method was developed for antioxidant raw products with thermal processing replaced by blending. The betanin loss, in this case, does not exceed 5 %. Optimal drying temperature of betanin-containing raw stock, after its preliminary processing, is 60 °С. It allows to keep up to 95 % of betanіn. Specific heat consumption for water evaporation out of the developed table beet based antioxidant plant compositions, with addition of rhubarb and lemon, is less by 4 to 5 % as compared to the initial components. Conclusions. Dependence of betanin loss in plant raw stock on the material temperature and composition components, in the course of their pre-drying preparation, was found. It was also found that water evaporation heat, for some antioxidant plant compositions developed, is less

Effect of drying conditions on drying kinetics and quality of aromatic Pandanus amaryllifolius leaves.

Science.gov (United States)

Rayaguru, Kalpana; Routray, Winny

2010-12-01

Pandanus amaryllifolius is a plant with aromatic leaves, which impart the characteristic flavour of aromatic rice. The quality of aromatic Pandanus leaves dried at low temperature (35 °C) and low RH (27%) in a heat pump dryer was evaluated and compared with those obtained from hot air drying at 45 °C. Thin-layer drying kinetics has been studied for both the conditions. To determine the kinetic parameters, the drying data were fitted to various semi-theoretical models. The goodness of fit was determined using the coefficient of determination, reduced chi square, and root mean square error. Aroma, colour, and overall acceptability determination of fresh and dried leaves were made using sensory evaluation. Drying of leaves took place mainly under the falling-rate period. The Page equation was found to be best among the proposed models to describe the thin-layer drying of Pandanus leaves with higher coefficient of determination. The effective moisture diffusivity values were also determined. The effect of low RH was prominent during the initial drying when the product was moist. The effect of temperature was prominent in the later part of drying, which acted as a driving force for moisture diffusion and hence the total drying time was reduced. Retention of aromatic compound 2-acetyl-1-pyrroline content was more in low temperature dried samples with higher sensory scores.

Investigation of influence of drying agent movement on the drying process effectiveness in the gravitational shelf dryer

Directory of Open Access Journals (Sweden)

N. O. Artyukhova

2017-12-01

Full Text Available The article stands for a research of the drying process efficiency of various approaches of reciprocal movement organization of drying agent and disperse material. It focuses on the results of shelf dryer investigation. The test condition was as follows: backflow of the drying agent and disperse material movement; backflow of the drying agent and disperse material movement with the drying agent recirculation; backflow of the drying agent and disperse material movement with the bypassing of drying agent and it’s putting on separate stage of gravitational shelf dryer. The influence of the drying agent movement organization on the characteristics of disperse material and drying agent, energy costs for this process and its efficiency is shown. The recommendations of usage of represented approaches of flows movement organization depending on the desired final moisture of the material as well as its physical and chemical properties are given. The proposed ways of reciprocal flows movement organization allow to reduce the costs of drying agent heating or to increase the efficiency of moisture removal at constant energy consumption.

Spontaneous Bladder Perforation in an Infant Neurogenic Bladder: Laparoscopic Management

Directory of Open Access Journals (Sweden)

Daniel Cabezalí Barbancho

2013-01-01

Full Text Available Spontaneous bladder perforation is an uncommon event in childhood. It is usually associated with bladder augmentation. We are presenting a case of bladder rupture in an infant with neurogenic bladder without prior bladder surgery. Three days after lipomyelomeningocele excision the patient showed signs and symptoms of acute abdomen. The ultrasound exploration revealed significant amount of intraperitoneal free fluid and therefore a laparoscopic exploration was performed. A posterior bladder rupture was diagnosed and repaired laparoscopically. Currently, being 3 years old, she keeps successfully dry with clean intermittent catheterization. Neurogenic bladder voiding function can change at any time of its evolution and lead to complications. Early diagnosis of spontaneous bladder rupture is of paramount importance, so it is essential to think about it in the differential diagnosis of acute abdomen.

Photochemically-induced ischemia of the rat sciatic nerve produces a dose-dependent and highly reproducible mechanical, heat and cold allodynia, and signs of spontaneous pain.

Science.gov (United States)

Kupers, R; Yu, W; Persson, J K; Xu, X J; Wiesenfeld-Hallin, Z

1998-05-01

Sensory abnormalities and changes in spontaneous behavior were examined after a photochemically induced ischemic lesion of the rat sciatic nerve. Male adult rats were anesthetized and the sciatic nerve was exposed. After the intravenous injection of a photosensitizing dye, erythrosin B, the exposed nerve was irradiated just proximal to the nerve trifurcation with light from an argon laser. Three different irradiation times were used, 30 s, 1 and 2 min. In sham-operated rats, the exposed sciatic nerve was irradiated for 2 min without prior injection of the erythrosin B. Rats were tested for the presence of mechanical, cold and heat allodynia or hyperalgesia. All the animals in the 1- and 2-min irradiation groups developed mechanical, cold and heat allodynia after nerve irradiation. A significant dose-dependent effect of laser exposure time was observed for all modalities tested (2 min > 1 min > 30 s = sham). The maximum effects were observed at 3 and 7 days postirradiation and remained present for up to 10 weeks. No significant contralateral effects were observed in any of the groups. In three separate groups of rats (1, 2 and 4 min of laser exposure), the presence of possible signs of spontaneous pain (paw shaking, paw elevation and freezing behavior) was tested. A significant and exposure time-dependent increase in spontaneous paw elevation and paw shaking was observed which was maximal at week 1, but resolved at 4 weeks (4 min > 2 min > 1 min > sham). In addition, animals in all ischemic groups, but not in the sham group, showed a significant increase in freezing behavior up to 4 weeks after nerve irradiation. Light microscopic evaluation of nerves removed 7 days post-irradiation, i.e. when maximal allodynia was observed, showed clear evidence of demyelination of large myelinated fibers. These data indicate that photochemically-induced peripheral nerve ischemia is associated with abnormal pain-related behaviors, including mechanical, thermal and cold allodynia

Integration of energy-efficient empty fruit bunch drying with gasification/combined cycle systems

International Nuclear Information System (INIS)

Aziz, Muhammad; Prawisudha, Pandji; Prabowo, Bayu; Budiman, Bentang Arief

2015-01-01

Highlights: • Novel integrated drying, gasification and combined cycle for empty fruit bunch. • Application of enhanced process integration to achieve high total energy efficiency. • The technology covers exergy recovery and process integration. • High overall energy efficiency can be achieved (about 44% including drying). - Abstract: A high-energy-efficient process for empty fruit bunch drying with integration to gasification and combined cycle processes is proposed. The enhancement is due to greater exergy recovery and more efficient process integration. Basically, the energy/heat involved in a single process is recovered as much as possible, leading to minimization of exergy destruction. In addition, the unrecoverable energy/heat is utilized for other processes through process integration. During drying, a fluidized bed dryer with superheated steam is used as the main evaporator. Exergy recovery is performed through exergy elevation via compression and effective heat coupling in a dryer and heat exchangers. The dried empty fruit bunches are gasified in a fluidized bed gasifier using air as the fluidizing gas. Furthermore, the produced syngas is utilized as fuel in the combined cycle module. From process analysis, the proposed integrated processes can achieve a relatively high energy efficiency. Compared to a standalone drying process employing exergy recovery, the proposed integrated drying can reduce consumed energy by about 1/3. In addition, the overall integrated processes can reach a total power generation efficiency of about 44%

Interpretation of specific-heat and spontaneous-magnetization anomalies at the reentrant superconducting - ferromagnetic transition in (Ho0.6Er0.4)Rh4B4

International Nuclear Information System (INIS)

Woolf, L.D.; Johnston, D.C.; Mook, H.A.; Koehler, W.C.; Maple, M.B.; Fisk, Z.

1981-09-01

Analysis of neutron-diffraction data on the compound (Ho 0 . 6 Er 0 . 4 )Rh 4 B 4 indicates that the Curie temperature is depressed by about 0.2 K due to the occurrence of superconductivity, in agreement with theoretical predictions. The temperature dependence of the specific heat in the vicinity of the first-order reentrant superconducting - ferromagnetic transition was computed by means of a simple model from the temperature dependence of the spontaneous magnetization of the Ho ions and was found to be in good agreement with the experimental data

Performance Analysis of Solar Assisted Fluidized Bed Dryer Integrated Biomass Furnace with and without Heat Pump for Drying of Paddy

Directory of Open Access Journals (Sweden)

M. Yahya

2016-01-01

Full Text Available The performances of a solar assisted fluidized bed dryer integrated biomass furnace (SA-FBDIBF and a solar assisted heat pump fluidized bed dryer integrated biomass furnace (SAHP-FBDIBF for drying of paddy have been evaluated, and also drying kinetics of paddy were determined. The SA-FBDIBF and the SAHP-FBDIBF were used to dry paddy from 11 kg with moisture content of 32.85% db to moisture content of 16.29% db (14% wb under an air mass flow rate of 0.1037 kg/s within 29.73 minutes and 22.95 minutes, with average temperatures and relative humidities of 80.3°C and 80.9°C and 12.28% and 8.14%, respectively. The average drying rate, specific energy consumption, and specific moisture extraction rate were 0.043 kg/minute and 0.050 kg/minute, 5.454 kWh/kg and 4.763 kWh/kg, and 0.204 kg/kWh and 0.241 kg/kWh for SA-FBDIBF and SAHP-FBDIBF, respectively. In SA-FBDIBF and SAHP-FBDIBF, the dryer thermal efficiencies were average values of 12.28% and 15.44%; in addition, the pickup efficiencies were 33.55% and 43.84% on average, whereas the average solar and biomass fractions were 10.9% and 10.6% and 36.6% and 30.4% for SA-FBDIBF and SAHP-FBDIBF, respectively. The drying of paddy occurred in the falling rate period. The experimental dimensionless moisture content data were fitted to three mathematical models. Page’s model was found best to describe the drying behaviour of paddy.

Simulation of the ACE L2 and ACE L5 MCCI experiment under dry surface conditions with ASTEC MEDICIS using an effective heat transfer model

Energy Technology Data Exchange (ETDEWEB)

Agethen, Kathrin; Koch, Marco K. [Bochum Univ. (Germany). Reactor Simulation and Safety Group

2013-07-01

In a postulated severe accident the loss of cooling can lead to a melting of the core and to a failure of the vessel. The molten core material discharges to the containment cavity and interacts with the concrete basemat. The heat up of the concrete leads to the release of sparing gases (H{sub 2}, CO{sub 2}, SiO), which stir the pool und causes chemical reactions. Especially the metals (Zr, Fe, Ni, Cr) in the corium are oxidized und the exothermic energy is released to the melt, which raises the melt temperature further. The release of combustible gases (H{sub 2}, CO) and fission products to the containment atmosphere occurs as a result. In the long time (>10 h) containment failure and basemat penetration may occur, which can lead to fission product release to the environment. For further development and validation, simulations of experiments in which molten core concrete interaction (MCCI) is investigated, are necessary. In this work the new available effective heat transfer model in MEDICIS is used to calculate experiments of the ACE program, in which generic corium material is heated up and interacts with the concrete basemat. Here, especially the ACE L2 experiment with siliceous concrete and the ACE L5 experiment with limestone common sand (LCS) concrete will be presented. These experiments enable to analyze the heat transfer from the interior of the melt to the upper surface under dry conditions. Secondary the modeling in ASTEC version 2.p2 with the effective heat transfer module in MEDICIS is described. Results of MEDICIS simulations will be discussed by means of phenomena like ablation behavior and erosions depth, layer temperature and surface heat loss. Finally the issue of an effective heat transfer coefficient for the surface under dry conditions without top flooding is figured out. (orig.)

Solar Heating System with Building-Integrated Heat Storage

DEFF Research Database (Denmark)

Heller, Alfred

1996-01-01

Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating, and due to storage. Heat demand is reduced due to direct solar heating, due to storage and due to lower heat losses through the ground. In theory, by running the system flow backwards through the sand storage, active heating...... can be achieved.The objective of the report is to present results from measured system evaluation andcalculations and to give guidelines for the design of such solar heating systems with building integrated sand storage. The report is aimed to non-technicians. In another report R-006 the main results...

Rodigo Uno (Italy) geothermal thermal energy for crop drying

International Nuclear Information System (INIS)

Facchini, U.; Sordelli, C.; Magnoni, S.; Cantadori, M.

1992-01-01

This paper outlines the chief design and performance features of a forage drying installation which makes use of locally available geothermal energy. The heat exchange is accomplished through a water-air exchanger directly fed by 59 degrees C geothermal springs. Two 80,000 cubic meter/hour ventilators, making use of this energy (58 to 38 degrees C heat exchange), raise the drying air temperature by 16 degrees C, while providing an overall drying capacity of 43,200 kg/day. The balance of available 38 degrees C geothermal energy is being employed by a local aquaculture farm. The paper comments on the economic and environmental benefits being derived from this direct utilization of geothermal energy

Neuropathic ocular pain: an important yet underevaluated feature of dry eye

Science.gov (United States)

Galor, A; Levitt, R C; Felix, E R; Martin, E R; Sarantopoulos, C D

2015-01-01

Dry eye has gained recognition as a public health problem given its prevalence, morbidity, and cost implications. Dry eye can have a variety of symptoms including blurred vision, irritation, and ocular pain. Within dry eye-associated ocular pain, some patients report transient pain whereas others complain of chronic pain. In this review, we will summarize the evidence that chronicity is more likely to occur in patients with dysfunction in their ocular sensory apparatus (ie, neuropathic ocular pain). Clinical evidence of dysfunction includes the presence of spontaneous dysesthesias, allodynia, hyperalgesia, and corneal nerve morphologic and functional abnormalities. Both peripheral and central sensitizations likely play a role in generating the noted clinical characteristics. We will further discuss how evaluating for neuropathic ocular pain may affect the treatment of dry eye-associated chronic pain. PMID:25376119

Modelling spontaneous ignition of wood, char and RDF in a lab-scale packed bed

NARCIS (Netherlands)

Blijderveen, M.; Bramer, Eduard A.; Brem, Gerrit

2013-01-01

Many municipal waste combustors use preheated primary air in the first zone to dry the waste. In most cases the preheat temperature does not exceed 140 °C. In previous experiments it is found that at temperatures around 200 °C, in some circumstances, self- or spontaneous ignition can be achieved.

Modelling spontaneous ignition of wood, char and RDF in a lab-scale packed bed

NARCIS (Netherlands)

Blijderveen, M. van; Bramer, E.A.; Brem, G.

2013-01-01

Many municipal waste combustors use preheated primary air in the first zone to dry the waste. In most cases the preheat temperature does not exceed 140°C. In previous experiments it is found that at temperatures around 200°C, in some circumstances, self- or spontaneous ignition can be achieved.

Heat Transfer Analysis of an Optimized, Flexible Holder System for Freeze-Drying in Dual Chamber Cartridges Using Different State-of-the-Art PAT Tools.

Science.gov (United States)

Korpus, Christoph; Pikal, Michael; Friess, Wolfgang

2016-11-01

The aim of this study was to determine the heat transfer characteristics of an optimized flexible holder device, using Tunable Diode Laser Absorption Spectroscopy, the Pressure Rise Test, and the gravimetric procedure. Two different controlled nucleation methods were tested, and an improved sublimation process, "preheated plate," was developed. Tunable Diode Laser Absorption Spectroscopy identified an initial sublimation burst phase. Accordingly, steady-state equations were adapted for the gravimetric procedure, to account for this initial non-steady-state period. The heat transfer coefficient, K DCC , describing the transfer from the holder to the DCC, was the only heat transfer coefficient showing a clear pressure dependence with values ranging from 3.81E-04 cal/(g·cm 2 ·K) at 40 mTorr to 7.38E-04 cal/(g·cm 2 ·K) at 200 mTorr. The heat transfer coefficient, K tot , reflecting the overall energy transfer via the holder, increased by around 24% from 40 to 200 mTorr. This resulted in a pressure-independent sublimation rate of around 42 ± 1.06 mg/h over the whole pressure range. Hence, this pressure-dependent increase in energy transfer completely compensated the decrease in driving force of sublimation. The "flexible holder" shows a substantially reduced impact of atypical radiation, improved drying homogeneity, and ultimately a better transferability of the freeze-drying cycle for process optimization. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Energy-saving drying and its application

Science.gov (United States)

Kovbasyuk, V. I.

2015-09-01

Superheated steam is efficiently applied as a coolant for the intensification of drying, which is an important component of many up-to-date technologies. However, traditional drying is extremely energy consuming, and many drying apparatus are environmentally unfriendly. Thus, it is important to implement the proposed drying technique using superheated steam under pressure significantly higher than the atmospheric one with subsequent steam transfer for use in a turbine for electric power generation as a compensation of energy costs for drying. This paper includes a brief thermodynamic analysis of such a technique, its environmental advantages, and possible benefits of the use of wet wastes and obtaining high-quality fuels from wet raw materials. A scheme is developed for the turbine protection from impurities that can occur in the steam at drying. Potential advantage of the technique are also the absence of heating surfaces that are in contact with wet media, the absence of the emissions to the atmosphere, and the use of low potential heat for desalination and the purification of water. The new drying technique can play an extremely important part in the implementation in the field of thermal destruction of anthropogenic wastes. In spite of the promotion of waste sorting to obtain valuable secondary raw materials, the main problem of big cities is nonutilizable waste, which makes not less than 85% of the starting quantity of waste. This can only be totally solved by combustion, which even more relates to the sewage sludge utilization. The wastes can be safely and efficiently combusted only provided that they are free of moisture. Combustion temperature optimization makes possible full destruction of dioxins and their toxic analogues.

Freeze Drying of Fruits and Vegetables: A Laboratory Experiment.

Science.gov (United States)

Noble, Richard D.

1979-01-01

Describes a laboratory experiment for freeze-drying fruits and vegetables which aims to expose college students to the principles of drying and simultaneous heat and mass transfer. The experimental apparatus, procedure of the experiment, and data analysis are also included. (HM)

Integration of biomass fast pyrolysis and precedent feedstock steam drying with a municipal combined heat and power plant

International Nuclear Information System (INIS)

Kohl, Thomas; Laukkanen, Timo P.; Järvinen, Mika P.

2014-01-01

Biomass fast pyrolysis (BFP) is a promising pre-treatment technology for converting biomass to transport fuel and in the future also for high-grade chemicals. BFP can be integrated with a municipal combined heat and power (CHP) plant. This paper shows the influence of BFP integration on a CHP plant's main parameters and its effect on the energetic and environmental performance of the connected district heating network. The work comprises full- and part-load operation of a CHP plant integrated with BFP and steam drying. It also evaluates different usage alternatives for the BFP products (char and oil). The results show that the integration is possible and strongly beneficial regarding energetic and environmental performance. Offering the possibility to provide lower district heating loads, the operation hours of the plant can be increased by up to 57%. The BFP products should be sold rather than applied for internal use as this increases the district heating network's primary energy efficiency the most. With this integration strategy future CHP plants can provide valuable products at high efficiency and also can help to mitigate global CO 2 emissions. - Highlights: • Part load simulation of a cogeneration plant integrated with biomas fast pyrolysis. • Analysis of energetic and environmental performance. • Assessment of different uses of the pyrolysis products

Modeling of a heat sink and high heat flux vapor chamber

Science.gov (United States)

Vadnjal, Aleksander

conductivity and (2) internal heat transfer coefficient. Volume averaging theory (VAT) is used to rigorously cast the point wise conservation of energy, momentum and mass equations into a form that represents the thermal and hydraulic properties of the micro channel (porous media) morphology. Using the resulting VAT based field equations, optimization of a micro channel heated from one side is used to determine the optimum micro channel morphology. A small square of 1 cm2 is chosen as an example and the thermal resistance, 0C/W, and pressure drop are shown as a function of Reynolds number. The high heat flux removal on small surfaces at moderately small temperatures is achieved by bi-porous evaporator The device was analyzed with the possibility of heat flux magnitudes exceeding 1kW/cm2 by using advantages of a dual pore structure of a bi-porous wick. The heat transfer model of a thin bi-porous wick is developed and it incorporates thermo-physical properties of a bi-porous media. It is shown that physics of heat removal is characterized in three stages; conduction, big pore drying out and small pore drying out. The operating conditions of the wick have to be in a safe margin away from the total dry out. A complete dry out of the wick inevitably leads to the burn out, therefore more concern has been added to modeling of big pore dry out, since this will be a desired operational. The construction of the boiling/evaporation curves was successfully constructed by the model showing that the physic of heat removal on two different length scales is governed by thermo-physical properties for the appropriate scale. The model shows good prediction for various combinations of big and small pores size in the bi-porous wicks tested.

Review on advanced of solar assisted chemical heat pump dryer for agriculture produce

International Nuclear Information System (INIS)

Fadhel, M.I.; Sopian, K.; Daud, W.R.W.; Alghoul, M.A.

2011-01-01

Over the past three decades there has been nearly exponential growth in drying R and D on a global scale. Improving of the drying operation to save energy, improve product quality as well as reduce environmental effect remained as the main objectives of any development of drying system. A solar assisted chemical heat pump dryer is a new solar drying system, which have contributed to better cost-effectiveness and better quality dried products as well as saving energy. A solar collector is adapted to provide thermal energy in a reactor so a chemical reaction can take place. This reduces the dependency of the drying technology on fossil energy for heating. In this paper a review on advanced of solar assisted chemical heat pump dryer is presented (the system model and the results from experimental studies on the system performance are discussed). The review of heat pump dryers and solar assisted heat pump dryer is presented. Description of chemical heat pump types and the overview of chemical heat pump dryer are discussed. The combination of chemical heat pump and solar technology gives extra efficiency in utilizing energy. (author)

Spontaneous colonization of restored dry grasslands by target species: restoration proceeds beyond sowing regional seed mixtures

Czech Academy of Sciences Publication Activity Database

Johanidesová, E.; Fajmon, K.; Jongepierová, I.; Prach, Karel

2015-01-01

Roč. 70, č. 4 (2015), s. 631-638 ISSN 0142-5242 Institutional support: RVO:67985939 Keywords : restoration * grasslands * spontaneous colonization Subject RIV: EH - Ecology, Behaviour Impact factor: 1.617, year: 2015

Dry storage cell for radioactive material

International Nuclear Information System (INIS)

Bradley, N.

1982-01-01

In a dry storage cell for irradiated nuclear fuel or other highly active waste, cooling air flow is by natural draught in heat exchange with fuel containing canisters housed in channels. To inhibit corrosion by ensuring that the temperature of the air flowing over the canisters does not fall below the dew point when heat generation by decay has fallen, a fraction of the heat energy transferred to the cooling air is recirculated to the air upstream of the canisters. Recirculation of heat energy is effected by recirculation of a fraction of the hot air from downstream of the canisters. (author)

Spontaneous mutation by mutagenic repair of spontaneous lesions in DNA

International Nuclear Information System (INIS)

Hastings, P.J.; Quah, S.-K.; Borstel, R.C. von

1976-01-01

It is stated that strains of yeast carrying mutations in many of the steps in pathways repairing radiation-induced damage to DNA have enhanced spontaneous mutation rates. Most strains isolated because they have enhanced spontaneous mutation carry mutations in DNA repair systems. This suggests that much spontaneous mutation arises by mutagenic repair of spontaneous lesions. (author)

Atmospheric Spray Freeze-Drying: Numerical Modeling and Comparison With Experimental Measurements.

Science.gov (United States)

Borges Sebastião, Israel; Robinson, Thomas D; Alexeenko, Alina

2017-01-01

Atmospheric spray freeze-drying (ASFD) represents a novel approach to dry thermosensitive solutions via sublimation. Tests conducted with a second-generation ASFD equipment, developed for pharmaceutical applications, have focused initially on producing a light, fine, high-grade powder consistently and reliably. To better understand the heat and mass transfer physics and drying dynamics taking place within the ASFD chamber, 3 analytical models describing the key processes are developed and validated. First, by coupling the dynamics and heat transfer of single droplets sprayed into the chamber, the velocity, temperature, and phase change evolutions of these droplets are estimated for actual operational conditions. This model reveals that, under typical operational conditions, the sprayed droplets require less than 100 ms to freeze. Second, because understanding the heat transfer throughout the entire freeze-drying process is so important, a theoretical model is proposed to predict the time evolution of the chamber gas temperature. Finally, a drying model, calibrated with hygrometer measurements, is used to estimate the total time required to achieve a predefined final moisture content. Results from these models are compared with experimental data. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

EXPERIMENTAL STUDY OF THERMAL EFFECT OF DRYING, HEATING, BLOWING MACHINE WITH DIFFERENT STAGE

OpenAIRE

Aditya Pratap Singh; Disha Dinesh Sahni; Arpit Dubey

2016-01-01

Drying is the oldest method of preserving food. The early American settlers dried foods such as corn, apple slices, currants, grapes, and meat. Compared with other methods, drying is quite simple. In fact, you may already have most of the equipment on hand. Dried foods keep well because the moisture content is so low that spoilage organisms cannot grow. Drying will never replace canning and freezing because these methods do a better job of retaining the taste, appearance, and nutritive va...

Reactor container facility

International Nuclear Information System (INIS)

Saito, Takashi; Nagasaka, Hideo.

1990-01-01

A dry-well pool for spontaneously circulating stored pool water and a suppression pool for flooding a pressure vessel by feeding water, when required, to a flooding gap by means of spontaneous falling upto the flooding position, thereby flooding the pressure vessel are contained at the inside of a reactor container. Thus, when loss of coolant accidents such as caused by main pipe rupture accidents should happen, pool water in the suppression pool is supplied to the flooding gap by spontaneously falling. Further, if the flooding water uprises exceeding a predetermined level, the flooding gap is in communication with the dry-well pool at the upper and the lower portions respectively. Accordingly, flooding water at high temperature heated by the after-heat of the reactor core is returned again into the flooding gap to cool the reactor core repeatedly. (T.M.)

A rice husk gasifier for paddy drying

International Nuclear Information System (INIS)

Mirani, A.A.; Kalwar, S.A.; Ahmad, M.

2013-01-01

Due to energy crisis and constant increase in the price of fossil fuels, the world's trend changes to renewable sources of energy like solar, wind and biomass gasification. Substantial biomass potential is available in Pakistan in the form of agriculture or forest residue (rice straw, rice husk, cotton stalks, corn cobs, wood chips, wood saw, etc.). These can be best utilised for the production of producer gas or synthetic gas that can be used for drying of agricultural crops. The drying process is an important activity of post harvest processing for long-term storage. Rice husk is nowadays commonly used for biomass gasification and its heat content value is about 15MJ/kg. It constitutes about 30 percent of rice production. A rice husk gasifier was developed and evaluated on paddy drying at Japan International Cooperation Agency (JICA), Tsukuba International Center (TBIC), Japan. Rice husk gasifier has following major components; husk feeding system, ash chamber, burner, centrifugal fan, drying chamber, gasifier reactor, air duct and an electric motor of 0.37kW. The average drying plenum air temperature was recorded as 45 degree C during the drying process. The paddy 'IR 28' from initial moisture content of 24% was dried up to 14% moisture content for about 3.33h consuming 3kg/h of rice husk. The efficiency was found to be 58%. The rice husk gasifier can also be used for drying the fruits and vegetables, provided that heat exchanger should be attached with it. The overall performance of rice husk gasifier was satisfactory and will be beneficial for small scale farmers, food processors and millers as well. (author)

Fuel-Cell Structure Prevents Membrane Drying

Science.gov (United States)

Mcelroy, J.

1986-01-01

Embossed plates direct flows of reactants and coolant. Membrane-type fuel-cell battery has improved reactant flow and heat removal. Compact, lightweight battery produces high current and power without drying of membranes.

Air dehumidification and drying processes

Energy Technology Data Exchange (ETDEWEB)

Steiner, R.

1988-07-01

Details are given on the physical principles of air dehumidification and drying as well as on appropriate systems available on the market. Reference is made to dehumidification through condensation (intermittent compressor or electric auxiliary heater defrosting, reversible-circuit hot gas bypass defrosting), air drying through sorption (sorbents, regeneration through heat inputs), the operation of absorptive dryers (schematic sketches), and the change of state of air (Mollier h,x-diagramm). Practical examples refer to the dehumidification of storage rooms, archives, and waterworks as well as to air drying in the pharmaceutical industry, the pastry and candy industry, the food industry, and the drying (preservation) of turbines and generators during long standstill periods. A diagramm shows that while adsorption processes are efficient at temperatures below 80/sup 0/C, low-temperature dehumidification is efficient at temperatures above. (HWJ).

Research supporting potential modification of the NASA specification for dry heat microbial reduction of spacecraft hardware

Science.gov (United States)

Spry, James A.; Beaudet, Robert; Schubert, Wayne

Dry heat microbial reduction (DHMR) is the primary method currently used to reduce the microbial load of spacecraft and component parts to comply with planetary protection re-quirements. However, manufacturing processes often involve heating flight hardware to high temperatures for purposes other than planetary protection DHMR. At present, the specifica-tion in NASA document NPR8020.12, describing the process lethality on B. atrophaeus (ATCC 9372) bacterial spores, does not allow for additional planetary protection bioburden reduction credit for processing outside a narrow temperature, time and humidity window. Our results from a comprehensive multi-year laboratory research effort have generated en-hanced data sets on four aspects of the current specification: time and temperature effects in combination, the effect that humidity has on spore lethality, and the lethality for spores with exceptionally high thermal resistance (so called "hardies"). This paper describes potential modifications to the specification, based on the data set gener-ated in the referenced studies. The proposed modifications are intended to broaden the scope of the current specification while still maintaining confidence in a conservative interpretation of the lethality of the DHMR process on microorganisms.

Cooling of a microchannel with thin evaporating liquid film sheared by dry gas flow

Science.gov (United States)

Kabova, Yu O.; Kuznetsov, V. V.

2017-11-01

A joint motion of thin liquid film and dry gas in a microchannel is investigated numerically at different values of initial concentration of the liquid vapor in the gas phase, taking into account the evaporation process. Major factors affecting the temperature distribution in the liquid and the gas phases are as follows: transfer of heat by liquid and gas flows, heat loses due to evaporation, diffusion heat exchange. Comparisons of the numerical results for the case of the dry gas and for the case of equilibrium concentration of vapor in the gas have been carried out. It is shown that use of dry gas enhances the heat dissipation from the heater. It is found out that not only intense evaporation occurs near the heating areas, but also in both cases vapor condensation takes place below the heater in streamwise direction.

Heat jettisoning from solar-thermal driven LiBr-H{sub 2}O absorber cooling units by pulsed spraying a dry cooler with water; Waermeabwurf aus einer solarthermisch getriebenen LiBr- H{sub 2}O Absorptionskaeltemaschine durch gepulstes Bespruehen eines Trockenkuehlers mit Wasser

Energy Technology Data Exchange (ETDEWEB)

Gantenbein, P.; Helfenberger, R.; Frank, E.

2010-07-01

This short, illustrated final report discusses the removal of heat from solar-thermal driven LiBr-H{sub 2}O absorber cooling units by pulsed spraying a dry cooler with water. The reduction of electricity consumption for room cooling using conventional chillers is examined. Heat dissipation using open cooling towers and the disadvantages encountered are compared with heat dissipation using a dry cooler with heat-exchanger and fans. Additional evaporation cooling achieved by spraying the heat exchanger with water is described and discussed. The results of measurements made at the Institute for Solar Technology in Rapperswil, Switzerland, are presented and discussed.

Studies on infrared drying of paper, use of integrating spheres in ftir-measurements, and heat and mass transfer inside paper. Thesis

Energy Technology Data Exchange (ETDEWEB)

Ojala, K

1993-11-05

The effect of various factors on the efficiency of infrared (IR) dryers has been studied by modeling and simulation of radiative heat transfer in these dryers. Generally, 20-35% of the radiation from electrical IR dryers becomes absorbed by the web, whereas in the case of a gas-fired dryer 30-50% of the energy becomes absorbed. The efficiency is strongly dependent on the dryer design, power, geometry, cleanness, and the material to be dried.

Mathematical Modeling of Microwave-Assisted Convective Heating and Drying of Grapes

Science.gov (United States)

This research studied the processing performance and product quality of Thompson seedless grapes dried using microwave-assisted convective hot air drying as well as the effect of blanching and dipping pretreatments. Two pretreatment methods were compared, dipping into 2% ethyl oleate (V/V) and 5% p...

Improvement of water transport mechanisms during potato drying by applying ultrasound.

Science.gov (United States)

Ozuna, César; Cárcel, Juan A; García-Pérez, José V; Mulet, Antonio

2011-11-01

The drying rate of vegetables is limited by internal moisture diffusion and convective transport mechanisms. The increase of drying air temperature leads to faster water mobility; however, it provokes quality loss in the product and presents a higher energy demand. Therefore, the search for new strategies to improve water mobility during convective drying constitutes a topic of relevant research. The aim of this work was to evaluate the use of power ultrasound to improve convective drying of potato and quantify the influence of the applied power in the water transport mechanisms. Drying kinetics of potato cubes were increased by the ultrasonic application. The influence of power ultrasound was dependent on the ultrasonic power (from 0 to 37 kW m(-3) ), the higher the applied power, the faster the drying kinetic. The diffusion model considering external resistance to mass transfer provided a good fit of drying kinetics. From modelling, it was observed a proportional and significant (P mass transfer coefficient. The ultrasonic application during drying represents an interesting alternative to traditional convective drying by shortening drying time, which may involve an energy saving concerning industrial applications. In addition, the ultrasonic effect in the water transport is based on mechanical phenomena with a low heating capacity, which is highly relevant for drying heat sensitive materials and also for obtaining high-quality dry products. Copyright © 2011 Society of Chemical Industry.

Study of microwave drying of wet materials based on one-dimensional two-phase model

Science.gov (United States)

Salomatov, Vl V.; Karelin, V. A.

2017-11-01

Currently, microwave is one of the most interesting ways to conduct drying of dielectric materials, in particular coal. In this paper, two processes were considered - heating and drying. The temperature field of the coal semi-mass in the heating mode is found analytically strictly with the use of integral transformations. The drying process is formulated as a nonlinear Stephen problem with a moving boundary of the liquid-vapor phase transformation. The temperature distribution, speed and drying time in this mode are determined approximately analytically. Parametric analysis of the influence of the material and boundary conditions on the dynamics of warming up and drying is revealed.

Comparative Survival Rates of Human-Derived Probiotic Lactobacillus paracasei and L. salivarius Strains during Heat Treatment and Spray Drying

Science.gov (United States)

Gardiner, G. E.; O'Sullivan, E.; Kelly, J.; Auty, M. A. E.; Fitzgerald, G. F.; Collins, J. K.; Ross, R. P.; Stanton, C.

2000-01-01

Spray drying of skim milk was evaluated as a means of preserving Lactobacillus paracasei NFBC 338 and Lactobacillus salivarius UCC 118, which are human-derived strains with probiotic potential. Our initial experiments revealed that NFBC 338 is considerably more heat resistant in 20% (wt/vol) skim milk than UCC 118 is; the comparable decimal reduction times were 11.1 and 1.1 min, respectively, at 59°C. An air outlet temperature of 80 to 85°C was optimal for spray drying; these conditions resulted in powders with moisture contents of 4.1 to 4.2% and viable counts of 3.2 × 109 CFU/g for NFBC 338 and 5.2 × 107 CFU/g for UCC 118. Thus, L. paracasei NFBC 338 survived better than L. salivarius UCC 118 during spray drying; similar results were obtained when we used confocal scanning laser microscopy and LIVE/DEAD BacLight viability staining. In addition, confocal scanning laser microscopy revealed that the probiotic lactobacilli were located primarily in the powder particles. Although both spray-dried cultures appeared to be stressed, as shown by increased sensitivity to NaCl, bacteriocin production by UCC 118 was not affected by the process, nor was the activity of the bacteriocin peptide. The level of survival of NFBC 338 remained constant at ∼1 × 109 CFU/g during 2 months of powder storage at 4°C, while a decline in the level of survival of approximately 1 log (from 7.2 × 107 to 9.5 × 106 CFU/g) was observed for UCC 118 stored under the same conditions. However, survival of both Lactobacillus strains during powder storage was inversely related to the storage temperature. Our data demonstrate that spray drying may be a cost-effective way to produce large quantities of some probiotic cultures. PMID:10831444

CROSS-TOLERANCE MECHANISM INDUCTION IN MELON SEEDS BY PRIMING PRIOR DRYING

Directory of Open Access Journals (Sweden)

Jean Marcel Sousa Lira

2015-04-01

Full Text Available The loss of benefits after re-drying is one of the drawbacks of the seed priming technique. Different types of stresses have been used before re-drying to preserve the priming benefits. This process may be seen as promoting cross tolerance to increase the defense mechanisms that prevent loss of viability in seeds primed after drying. We tested the effect of some stresses to induce cross-tolerance and different drying conditions with the aim of maintaining priming benefits in melon seeds. The seeds were primed in an aerated KNO3 solution (0.35M, -1.7MPa, 25 °C, in the dark for six days. The primed seeds were then submitted to slow drying, fast drying, cold shock + slow drying, cold shock + fast drying, heat shock + slow drying, heat shock + fast drying, PEG + slow drying, PEG + fast drying, ABA + slow drying, ABA + fast drying and no drying (planted directly after priming. We evaluated antioxidant enzyme activities (SOD, CAT and APX, germinability, mean time of germination (MTG and mean rate of germination (MRG. A completely randomized design was used with three repetitions of 50 seeds in each treatment. Data were analyzed by ANOVA and means were compared by the Scott-Knott test (p ≤ 0.05. ABA increased SOD activity after drying and CAT activity was reduced by priming. APX activity was not observed. The stress submission prior to re-drying improved the MRG and reduced MTG. Therefore, the induction of the cross-tolerance mechanism could be effective to maintain priming benefits in melon seeds.

Mechanism of subcooled water flow boiling critical heat flux in a circular tube at high liquid Reynolds number

International Nuclear Information System (INIS)

Hata, K.; Fukuda, K.; Masuzaki, S.

2014-01-01

The subcooled boiling heat transfer and the steady state critical heat flux (CHF) in a vertical circular tube for the flow velocities (u=3.95 to 30.80 m/s) are systematically measured by the experimental water loop comprised of a multistage canned-type circulation pump with high pump head. The SUS304 test tube of inner diameter (d=6 mm) and heated length (L=59.5 mm) is used in this work. The outer surface temperatures of the SUS304 test tube with heating are observed by an infrared thermal imaging camera and a video camera. The subcooled boiling heat transfers for SUS304 test tube are compared with the values calculated by other workers' correlations for the subcooled boiling heat transfer. The influence of flow velocity on the subcooled boiling heat transfer and the CHF is investigated into details based on the experimental data. Nucleate boiling surface superheats at the CHF are close to the lower limit of the heterogeneous spontaneous nucleation temperature and the homogeneous spontaneous nucleation temperature. The dominant mechanism of the subcooled flow boiling CHF on the SUS304 circular tube is discussed at high liquid Reynolds number. On the other hand, theoretical equations for k-ε turbulence model in a circular tube of a 3 mm in diameter and a 526 mm long are numerically solved for heating of water on heated section of a 3 mm in diameter and a 67 mm long with various thicknesses of conductive sub-layer by using PHOENICS code under the same conditions as the experimental ones previously obtained considering the temperature dependence of thermo-physical properties concerned. The Platinum (Pt) test tube of inner diameter (d=3 mm) and heated length (L=66.5 mm) was used in this experiment. The thicknesses of conductive sub-layer from non-boiling regime to CHF are clarified. The thicknesses of conductive sub-layer at the CHF point are evaluated for various flow velocities. The experimental values of the CHF are also compared with the corresponding

Evaluation of convective heat transfer coefficient of various crops in cyclone type dryer

International Nuclear Information System (INIS)

Akpinar, E. Kavak

2005-01-01

In this paper, an attempt was made to evaluate the convective heat transfer coefficient during drying of various crops and to investigate the influences of drying air velocity and temperature on the convective heat transfer coefficient. Drying was conducted in a convective cyclone type dryer at drying air temperatures of 60, 70 and 80 deg. C and velocities of 1 and 1.5 m/s using rectangle shaped potato and apple slices (12.5 x 12.5 x 25 mm) and cylindrical shaped pumpkin slices (35 x 5 mm). The temperature changes of the dried crops and the temperature of the drying air were measured during the drying process. It was found that the values of convective heat transfer coefficient varied from crop to crop with a range 30.21406 and 20.65470 W/m 2 C for the crops studied, and it was observed that the convective heat transfer coefficient increased in large amounts with the increase of the drying air velocity but increased in small amounts with the rise of the drying air temperature

Evaluation of convective heat transfer coefficient of various crops in cyclone type dryer

Energy Technology Data Exchange (ETDEWEB)

Akpinar, E. Kavak [Mechanical Engineering Department, Firat University, 23279 Elazig (Turkey)]. E-mail: eakpinar@firat.edu.tr

2005-09-15

In this paper, an attempt was made to evaluate the convective heat transfer coefficient during drying of various crops and to investigate the influences of drying air velocity and temperature on the convective heat transfer coefficient. Drying was conducted in a convective cyclone type dryer at drying air temperatures of 60, 70 and 80 deg. C and velocities of 1 and 1.5 m/s using rectangle shaped potato and apple slices (12.5 x 12.5 x 25 mm) and cylindrical shaped pumpkin slices (35 x 5 mm). The temperature changes of the dried crops and the temperature of the drying air were measured during the drying process. It was found that the values of convective heat transfer coefficient varied from crop to crop with a range 30.21406 and 20.65470 W/m{sup 2} C for the crops studied, and it was observed that the convective heat transfer coefficient increased in large amounts with the increase of the drying air velocity but increased in small amounts with the rise of the drying air temperature.

DESIGN ANDFABRICATION OF DISPOSING DRY WASTEMATERIAL USING WASTE DESTROYING MACHINE

OpenAIRE

Dr. Nischal P. Mungle1, MahendraNimkar2, ArchanaN. Mungle3, Manjushree Mule4

2018-01-01

The dry waste material is type of waste material, waste materials like solid waste, liquid waste in atmosphere leads to unhygienic situation which affects human health and chances of disease increases. In our project by burning the dry waste material we are trying to control the waste materials in atmosphere. By using heating coil we are going to burn the dry waste material and in this way we are eliminating the dry waste materials, the ash which will going to be formed after burning the dry ...

Heat transfer analysis of consolidated dry storage system for CANDU spent fuel considering environmental conditions of Wolsong site

International Nuclear Information System (INIS)

Lee, K. H.; Yoon, J. H.; Choi, B. I.; Lee, H. Y.

2004-01-01

The purpose of the present paper is to perform heat transfer analysis of the MACSTOR/KN-400 dry storage system for CANDU spent fuel in order to predict maximum concrete temperatures and temperature gradients. This module has twice the capacity of the existing MACSTOR-200, which is in operation at Gentilly-2. In the thermal design of the MACSTOR/KN-400, Thermal Insulation Panels(TIP) were introduced to reduce concrete temperatures and temperature gradients in the module caused by the high fuel heat loads. Environmental factors such as solar heat, daily temperature variations and ambient temperatures in summer and winter at Wolsong site and the assumed presence of hot baskets were taken into consideration in the simulations. Two cases were performed for the MACSTOR/KN-400: Off-normal cases in summer and winter. The maximum local concrete temperatures were predicted to be 63 .deg. C for the off-normal case. The temperature gradients in the concrete walls and roof are predicted to be 28C and 25C for off-normal operation in summer, incorporating a 3C uncertainty. In conclusion, this paper shows that the maximum temperature for the module is expected to meet the temperature limitations of ACI 349

Design manual. [High temperature heat pump for heat recovery system

Energy Technology Data Exchange (ETDEWEB)

Burch, T.E.; Chancellor, P.D.; Dyer, D.F.; Maples, G.

1980-01-01

The design and performance of a waste heat recovery system which utilizes a high temperature heat pump and which is intended for use in those industries incorporating indirect drying processes are described. It is estimated that use of this heat recovery system in the paper, pulp, and textile industries in the US could save 3.9 x 10/sup 14/ Btu/yr. Information is included on over all and component design for the heat pump system, comparison of prime movers for powering the compressor, control equipment, and system economics. (LCL)

Solar heating - a major source of renewable energy

International Nuclear Information System (INIS)

Bosselaar, L.

2001-01-01

Actions that can be taken to increase the uptake of technology for solar water heaters and solar buildings are discussed. An overview of existing technology covers solar water heating, solar buildings, space heating, solar cooling, solar drying, solar desalination. Solar water heating, solar buildings and solar crop drying are discussed individually under the sub-headings of (a) the technology; (b) the market; (c) potential; (d) economics and (e) market acceleration strategies. Other subjects discussed are market acceleration, main opportunities, R and D needs and conclusions. The IEA solar heating and solar cooling programme is described

Improving Malaysian cocoa quality through the use of dehumidified air under mild drying conditions.

Science.gov (United States)

Hii, Ching L; Law, Chung L; Cloke, Michael; Sharif, Suzannah

2011-01-30

Various studies have been conducted in the past to improve the quality of Malaysian cocoa beans. However, the processing methods still remain crude and lack technological advancement. In terms of drying, no previous study has attempted to apply advanced drying technology to improve bean quality. This paper presents the first attempt to improve the quality of cocoa beans through heat pump drying using constant air (28.6 and 40.4 °C) and stepwise (step-up 30.7-43.6-56.9 °C and step-down 54.9-43.9 °C) drying profiles. Comparison was made against hot air drying at 55.9 °C. Product quality assessment showed significant improvement in the quality of Malaysian cocoa beans. Quality was found to be better in terms of lower acidity (higher pH) and higher degree of browning (cut test) for cocoa beans dried using the step-up profile. All heat pump-dried samples showed flavour quality comparable to that of Ghanaian and better than that of Malaysian and Indonesian commercial samples. Step-up-dried samples showed the best flavour profile with high level of cocoa flavour, low in sourness and not excessive in bitterness and astringency. Dried cocoa samples from the step-up drying profile showed the best overall quality as compared with commercial samples from Malaysia, Indonesia and Ghana. The improvement of Malaysian cocoa bean quality is thus achievable through heat pump drying. 2010 Society of Chemical Industry.

Effects of Moist Heat and Dry Heat on the Nutritional Value of Velvet ...

African Journals Online (AJOL)

constitute lOand 20 perc~nt of the experimental diets andfed to laying hens. The results revealed an over- ... was ci better method of heat treatment than roasting, for velvet bfans fed to the laying hens. Keywords: Heat .... 'Vegetable oil was added to make up the required amount of energy in the diets. bProvide per kg diet: Vit ...

Combined Thermal Management and Power Generation Concept for the Spent Fuel Dry Storage Cask

International Nuclear Information System (INIS)

Kim, In Guk; Bang, In Cheol

2017-01-01

The management of the spent nuclear fuel generated by nuclear power plants is a major issue in Korea due to insufficient capacity of the wet storage pools. Therefore, it is considered that dry storage system is the one possible solution for storing spent fuel. A dual-purpose metal cask (transportation and storage) is currently developing in Korea. This cask has 21 of fuel assemblies and 16.8 kW of maximum decay heat. To evaluate the critical safety in normal/off normal and accident conditions, critical stabilities were conducted by using CSAS 6.0. The experimental investigation of heat removal of a concrete storage cask was also conducted under normal, off normal and accident conditions. The results of the evaluation showed a good safety of the dry storage cask. The results showed the enhanced thermal performance according to modification of flow rate. To verify combined thermal management and power generation concept, a new type of test facility for dry storage cask was designed in 1/10 scale of concrete dry storage cask. The experimental study involved the cooling methods that are an integrated system on the top of the dry cask and air flow path on the canister wall. The results showed the temperature distribution of the wall and inside of the dry cask at the normal condition. The influence of the change of the heat load and cooling system were investigated. The heat removal by the integrated system is approximately 20% of the total heat removal of the dry cask with reduced wall temperature. In these tests, economic analysis is conducted by applying the concept of the cost and efficiency. Under different decay power cases, the energy efficiency of the heat pipe and Stirling engine are determined and compared based on experimental results. The average efficiencies of the Stirling engine were the range of 2.375 to 3.247% under the power range of 35– 65W. These results showed that advanced dry storage concept had a better cooling performance in comparison with

Investigation on Solar Heating System with Building-Integrated Heat Storage

DEFF Research Database (Denmark)

Heller, Alfred

1996-01-01

Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating and due to storage. The storage affects the heat demand passively due to higher temperatures. Hence heat loss is reduced and passive heating is optioned. In theory, by running the system flow backwards, active heating can...... solar collector area of the system, was achieved. Active heating from the sand storage was not observed. The pay-back time for the system can be estimated to be similar to solar heated domestic hot water systems in general. A number of minor improvements on the system could be pointed out....

Drying wood waste with a pulse combustion dryer

Energy Technology Data Exchange (ETDEWEB)

Buchkowski, A.G. [Spectrum Engineering Corp., Ltd., Peterborough, Ontario (Canada); Kitchen, J.A. [John A. Kitchen, Ltd., Hastings, Ontario (Canada)

1993-12-31

There is a vast amount of wood waste available to be used as an alternate fuel if its moisture could be reduced efficiently. Tests have been conducted to assess an industrial dryer using pulse combustion as a heating source for drying wood waste; specifically sawdust and pulverized wet hog fuel. Pulse combustion offers the advantage of high heat transfer, efficient combustion, and low NO{sub x} emissions. The material is injected into the exhaust gases in the tailpipe of the combustor which uses natural gas or propane as a fuel. The turbulence created by the pulsations enhance the drying process by reducing the boundary layer thicknesses. The materials is further dried in a rotary drum. The material has been dried without scorching or burning in tests where the inlet moisture content has been as high as 60% on a wet basis. The outlet moisture contents achieved have typically been 10%. Analysis of the test data and cost estimates of the equipment indicate that the pulse combustion drying system is at least comparable to existing systems in terms of operating costs, and offers very significant savings in capital costs. Testing with various other materials such as wood pulp, sludges and peat is continuing to further assess the equipment`s performance.

Thermal influences on spontaneous rock dome exfoliation

Science.gov (United States)

Collins, Brian D.; Stock, Greg M.; Eppes, Martha C.; Lewis, Scott W.; Corbett, Skye C.; Smith, Joel B.

2018-01-01

Rock domes, with their onion-skin layers of exfoliation sheets, are among the most captivating landforms on Earth. Long recognized as integral in shaping domes, the exact mechanism(s) by which exfoliation occurs remains enigmatic, mainly due to the lack of direct observations of natural events. In August 2014, during the hottest days of summer, a granitic dome in California, USA, spontaneously exfoliated; witnesses observed extensive cracking, including a ~8000 kg sheet popping into the air. Subsequent exfoliation episodes during the following two summers were recorded by instrumentation that captured—for the first time—exfoliation deformation and stress conditions. Here we show that thermal cycling and cumulative dome surface heating can induce subcritical cracking that culminates in seemingly spontaneous exfoliation. Our results indicate that thermal stresses—largely discounted in dome formation literature—can play a key role in triggering exfoliation and therefore may be an important control for shaping domes worldwide.

7 CFR 52.3188 - Work sheet for dried prunes.

Science.gov (United States)

2010-01-01

... for dried prunes. Size and kind of container Container mark or identification Label or brand Varietal... fermentation, scars, heat damage, insect injury, other means, mold, dirt, foreign material, insect infestation... fermentation, scars, heat damage, insect injury, other means, mold, dirt, foreign material, insect infestation...

Drying tests conducted on Three Mile Island fuel canisters containing simulated debris

International Nuclear Information System (INIS)

Palmer, A.J.

1995-01-01

Drying tests were conducted on TMI-2 fuel canisters filled with simulated core debris. During these tests, canisters were dried by heating externally by a heating blanket while simultaneously purging the canisters' interior with hot, dry nitrogen. Canister drying was found to be dominated by moisture retention properties of a concrete filler material (LICON) used for geometry control. This material extends the drying process 10 days or more beyond what would be required were it not there. The LICON resides in a nonpurgeable chamber separate from the core debris, and because of this configuration, dew point measurements on the exhaust stream do not provide a good indication of the dew point in the canisters. If the canisters are not dried, but rather just dewatered, 140-240 lb of water (not including the LICON water of hydration) will remain in each canister, approximately 50-110 lb of which is pore water in the LICON and the remainder unbound water

Electric heating of a unit for uranium trioxide production

International Nuclear Information System (INIS)

Faron, R.; Striff, A.

1985-01-01

Ammonium diuranate U 2 O 7 (NH 4 ) 2 containing about 50% of water is dried and transformed by calcination in uranium trioxide UO 3 . Drying and calcination was obtained by air heated by two burners using domestic fuel. In 1984 the plant was transformed for utilization of electric heating improving maintenance cost, decreasing heat losses and by energy saving the payback period on investment is of 2.6 years [fr

Thin layer convective air drying of wild edible plant (Allium roseum) leaves: experimental kinetics, modeling and quality

OpenAIRE

Ben Haj Said, Leila; Najjaa, Hanen; Farhat, Abdelhamid; Neffati, Mohamed; Bellagha, Sihem

2014-01-01

The present study deals with the valorization of an edible spontaneous plant of the Tunisian arid areas: Allium roseum. This plant is traditionally used for therapeutic and culinary uses. Thin-layer drying behavior of Allium roseum leaves was investigated at 40, 50 and 60 °C drying air temperatures and 1 and l.5 m/s air velocity, in a convective dryer. The increase in air temperature significantly affected the moisture loss and reduced the drying time while air velocity was an insignificant f...

PhD Thesis Summary: Energy Efficient Multistage Zeolite Drying for Heat-Sensitive Products

NARCIS (Netherlands)

Djaeni, M.; Boxtel, van A.J.B.

2009-01-01

Although drying takes a significant part of the total energy usage in industry, currently available drying technology is often not efficient in terms of energy consumption. Generally, the energy efficiency for drying processes ranges between 20 and 60% depending on the dryer type and product to be

Building America Best Practices Series: Volume 2; Builders and Buyers Handbook for Improving New Home Efficiency, Comfort, and Durability in the Hot-Dry and Mixed-Dry Climates

Energy Technology Data Exchange (ETDEWEB)

None

2005-09-01

This guidebook is a resource to help builders large and small build high-quality, energy-efficient homes that achieve 30% energy savings in space conditioning and water heating in the hot-dry and mixed-dry climates.

EVALUATION OF THERMAL EFFICIENCY OF THE TECHNOLOGICAL SCHEME OF APPLE CHIPS AND DRIED FRUITS PRODUCTION

Directory of Open Access Journals (Sweden)

G. V. Kalashnikov

2014-01-01

Full Text Available The estimation of thermodynamic perfection of separate technological processes is executed at heat-moisture of handling of fruit and a line of manufacture of fruit apple chips and dried fruits. The technological scheme of a line of processing of fruits and manufactures of fruit chips on the basis of convection and the microwave-dryings suggested resource-saving. The technique is made and results of calculation of thermal expenses for various schemes of manufacture of apple chips are resulted. For the offered scheme material, thermal and power streams on the basis of balance parities of technological processes are certain. The comparative thermal production efficiency of apple chips for a base foreign variant and the offered technological scheme with the closed cycle of use of the heat-carrier and the combined convection-microwave-drying is shown. In this paper we define the thermal and energy flows for the processes of convective drying, pre-microwave drying, hydrothermal treatment and final microwave drying plant material, which are one of the main stages of the production of all kinds of fruit and vegetable concentrates, including fruit apple chips. Resource-saving ways moisture-heat of handling (hydration, blanching, drying, etc. produce raw materials in the production of food concentrates suggested a reduced water flow with a high degree of use of its potential power and microwave sources. To assess the thermal efficiency of the various processes and production schemes used as indicators of thermal efficiency and proposed value of specific heat (kJ / kg given mass productivity per unit of feedstock and translational moisture. The values of the mass fraction of the heat of material flows for the base and the proposed resource-saving production scheme fruit chips, for example, apple, based on a combination of convection-microwave drying each control surface.

Wheat cultivars selected for high Fv /Fm under heat stress maintain high photosynthesis, total chlorophyll, stomatal conductance, transpiration and dry matter.

Science.gov (United States)

Sharma, Dew Kumari; Andersen, Sven Bode; Ottosen, Carl-Otto; Rosenqvist, Eva

2015-02-01

The chlorophyll fluorescence parameter Fv /Fm reflects the maximum quantum efficiency of photosystem II (PSII) photochemistry and has been widely used for early stress detection in plants. Previously, we have used a three-tiered approach of phenotyping by Fv /Fm to identify naturally existing genetic variation for tolerance to severe heat stress (3 days at 40°C in controlled conditions) in wheat (Triticum aestivum L.). Here we investigated the performance of the previously selected cultivars (high and low group based on Fv /Fm value) in terms of growth and photosynthetic traits under moderate heat stress (1 week at 36/30°C day/night temperature in greenhouse) closer to natural heat waves in North-Western Europe. Dry matter accumulation after 7 days of heat stress was positively correlated to Fv /Fm . The high Fv /Fm group maintained significantly higher total chlorophyll and net photosynthetic rate (PN ) than the low group, accompanied by higher stomatal conductance (gs ), transpiration rate (E) and evaporative cooling of the leaf (ΔT). The difference in PN between the groups was not caused by differences in PSII capacity or gs as the variation in Fv /Fm and intracellular CO2 (Ci ) was non-significant under the given heat stress. This study validated that our three-tiered approach of phenotyping by Fv /Fm performed under increasing severity of heat was successful in identifying wheat cultivars differing in photosynthesis under moderate and agronomically more relevant heat stress. The identified cultivars may serve as a valuable resource for further studies to understand the physiological mechanisms underlying the genetic variability in heat sensitivity of photosynthesis. © 2014 Scandinavian Plant Physiology Society.

A case of BOOP-like pneumonia induced by radiotherapy after surgical resection of breast cancer which healed spontaneously

International Nuclear Information System (INIS)

Imamura, Masahiro; Sawada, Satoshi; Sougawa, Mitsuharu; Harima, Yoko; Kariya, Shuji; Yamaguchi, Kazuyuki

2004-01-01

The patient was a 67-year-old woman. After mastectomy, she received 50 Gy radiation to her chest wall using a tangential beam. About 3 months later, she developed dry cough, and an infiltrated shadow was noted in the irradiated lung. The shadow later moved to the opposite lung. The pneumonia healed spontaneously thereafter. This case is noteworthy since it endorses the previously reported clinical feature of broncholitis obliterans organizing pneumonia (BOOP), i.e., a high likelihood of spontaneous healing even when it is induced by radiotherapy. (author)

Simultaneous heat and mass transfer to air from a compact heat exchanger with water spray precooling and surface deluge cooling

International Nuclear Information System (INIS)

Zhang, Feini; Bock, Jessica; Jacobi, Anthony M.; Wu, Hailing

2014-01-01

Various methods are available to enhance heat exchanger performance with evaporative cooling. In this study, evaporative mist precooling, deluge cooling, and combined cooling schemes are examined experimentally and compared to model predictions. A flexible model of a compact, finned-tube heat exchanger with a wetted surface is developed by applying the governing conservation and rate equations and invoking the heat and mass transfer analogy. The model is applicable for dry, partially wet, or fully wet surface conditions and capable of predicting local heat/mass transfer, wetness condition, and pressure drop of the heat exchanger. Experimental data are obtained from wind tunnel experiments using a louver-fin flat-tube heat exchanger with single-phase tube-side flow. Total capacity, pressure drop, and water drainage behavior under various water usage rates and air face velocities are analyzed and compared to data for dry-surface conditions. A heat exchanger partitioning method for evaporative cooling is introduced to study partially wet surface conditions, as part of a consistent and general method for interpreting wet-surface performance data. The heat exchanger is partitioned into dry and wet portions by introducing a wet surface factor. For the wet part, the enthalpy potential method is used to determine the air-side sensible heat transfer coefficient. Thermal and hydraulic performance is compared to empirical correlations. Total capacity predictions from the model agree with the experimental results with an average deviation of 12.6%. The model is also exercised for four water augmentation schemes; results support operating under a combined mist precooling and deluge cooling scheme. -- Highlights: • A new spray-cooled heat exchanger model is presented and is validated with data. • Heat duty is shown to be asymptotic with spray flow rate. • Meaningful heat transfer coefficients for partially wet conditions are obtained. • Colburn j wet is lower than j dry

Spontaneous formation of densely packed shear bands of rotating fragments.

Science.gov (United States)

Åström, J A; Timonen, J

2012-05-01

Appearance of self-similar space-filling ball bearings has been suggested to provide the explanation for seismic gaps, shear weakness, and lack of detectable frictional heat formation in mature tectonic faults (shear zones). As the material in a shear zone fractures and grinds, it could be thought to eventually form a conformation that allows fragments to largely roll against each other without much sliding. This type of space-filling "ball bearing" can be constructed artificially, but so far how such delicate structures may appear spontaneously has remained unexplained. It is demonstrated here that first-principles simulations of granular packing with fragmenting grains indeed display spontaneous formation of shear bands with fragment conformations very similar to those of densely packed ball bearings.

Far-infrared irradiation drying behavior of typical biomass briquettes

International Nuclear Information System (INIS)

Chen, N.N.; Chen, M.Q.; Fu, B.A.; Song, J.J.

2017-01-01

Infrared radiation drying behaviors of four typical biomass briquettes (populus tomentosa leaves, cotton stalk, spent coffee grounds and eucalyptus bark) were investigated based on a lab-scale setup. The effect of radiation source temperatures (100–200 °C) on the far-infrared drying kinetics and heat transfer of the samples was addressed. As the temperature went up from 100 °C to 200 °C, the time required for the four biomass briquettes drying decreased by about 59–66%, and the average values of temperature for the four biomass briquettes increased by about 33–39 °C, while the average radiation heat transfer fluxes increased by about 3.3 times (3.7 times only for the leaves). The specific energy consumptions were 0.622–0.849 kW h kg"−"1. The Modified Midilli model had the better representing for the moisture ratio change of the briquettes. The values of the activation energy for the briquettes in the first falling rate stage were between 20.35 and 24.83 kJ mol"−"1, while those in the second falling rate stage were between 17.89 and 21.93 kJ mol"−"1. The activation energy for the eucalyptus bark briquette in two falling rate stages was the least one, and that for the cotton stalk briquette was less than that for the rest two briquettes. - Highlights: • Far infrared drying behaviors of four typical biomass briquettes were addressed. • The effect of radiation source temperatures on IR drying kinetics was stated. • Radiation heat transfer flux between the sample and heater was evaluated. • Midilli model had the better representing for the drying process of the samples.

Solar air heaters for industrial drying; Aquecedor solar de ar para secagem industrial

Energy Technology Data Exchange (ETDEWEB)

Braga, Everaldo Mendes [Governo do Estado da Paraiba, Joao Pessoa, PB (Brazil). Secretaria de Planejamento e Gestao

2008-07-01

The objective of this study is to encourage the use of solar energy in industrial drying of fruits, with the producers poles, at the same time, promote the rational use of energy for heat, or replacing the hydroelectric and oil derivatives for this purpose. This study is presented in the following chapters: availability of solar energy; details of constructive solar heated air; drying fruit; market. (author)

On nature of spontaneous elongation of polymers preliminarily stretched in adsorption-active media under irradiation

International Nuclear Information System (INIS)

Sinevich, E.A.; Prazdnichnyj, A.M.; Tikhomirov, V.S.; Bakeev, N.F.

1989-01-01

The nature of the spontaneous elongation under irradiation with fast electrons of polymers preliminary stretched in adsorption-active media has been studied. This effect is related with radiation-induced heating of microporous polymer samples. Its manifestation in amorphous PETP requires the presence of crazes having well developed microfibrillar structure. The spontaneous elongation effect is shown to be a result of crystallization of partially oriented material in transitional regions relating the oriented material of microfibrils inside crazes with nonstrained polymer between them

Numerical study on hygroscopic material drying in packed bed

Directory of Open Access Journals (Sweden)

M. Stakić

2011-06-01

Full Text Available The paper addresses numerical simulation for the case of convective drying of hygroscopic material in a packed bed, analyzing agreement between the simulated and the corresponding experimental results. In the simulation model of unsteady simultaneous one-dimensional heat and mass transfer between gas phase and dried material, it is assumed that the gas-solid interface is at thermodynamic equilibrium, while the drying rate of the specific product is calculated by applying the concept of a "drying coefficient". Model validation was done on the basis of the experimental data obtained with potato cubes. The obtained drying kinetics, both experimental and numerical, show that higher gas (drying agent velocities (flow-rates, as well as lower equivalent grain diameters, induce faster drying. This effect is more pronounced for deeper beds, because of the larger amount of wet material to be dried using the same drying agent capacity.

Effect of Deep Drying and Torrefaction Temperature on Proximate, Ultimate Composition, and Heating Value of 2-mm Lodgepole Pine (Pinus contorta) Grind.

Science.gov (United States)

Tumuluru, Jaya Shankar

2016-06-22

Deep drying and torrefaction compose a thermal pretreatment method where biomass is heated in the temperature range of 150-300 °C in an inert or reduced environment. The process parameters, like torrefaction temperature and residence time, have a significant impact on the proximate, ultimate, and energy properties. In this study, torrefaction experiments were conducted on 2-mm ground lodgepole pine ( Pinus contorta ) using a thermogravimetric analyzer. Both deep drying and torrefaction temperature (160-270 °C) and time (15-120 min) were selected. Torrefied samples were analyzed for the proximate, ultimate, and higher heating value. The results indicate that moisture content decreases with increases in torrefaction temperature and time, where at 270 °C and 120 min, the moisture content is found to be 1.15% (w.b.). Volatile content in the lodgepole pine decreased from about 80% to about 45%, and ash content increased from 0.77% to about 1.91% at 270 °C and 120 min. The hydrogen, oxygen, and sulfur content decreased to 3%, 28.24%, and 0.01%, whereas the carbon content and higher heating value increased to 68.86% and 23.67 MJ/kg at 270 °C and 120 min. Elemental ratio of hydrogen to carbon and oxygen to carbon (H/C and O/C) calculated at 270 °C and a 120-min residence time were about 0.56 and 0.47. Based on this study, it can be concluded that higher torrefaction temperatures ≥230 °C and residence time ≥15 min influence the proximate, ultimate, and energy properties of ground lodgepole pine.

Effect of Deep Drying and Torrefaction Temperature on Proximate, Ultimate Composition, and Heating Value of 2-mm Lodgepole Pine (Pinus contorta Grind

Directory of Open Access Journals (Sweden)

Jaya Shankar Tumuluru

2016-06-01

Full Text Available Deep drying and torrefaction compose a thermal pretreatment method where biomass is heated in the temperature range of 150–300 °C in an inert or reduced environment. The process parameters, like torrefaction temperature and residence time, have a significant impact on the proximate, ultimate, and energy properties. In this study, torrefaction experiments were conducted on 2-mm ground lodgepole pine (Pinus contorta using a thermogravimetric analyzer. Both deep drying and torrefaction temperature (160–270 °C and time (15–120 min were selected. Torrefied samples were analyzed for the proximate, ultimate, and higher heating value. The results indicate that moisture content decreases with increases in torrefaction temperature and time, where at 270 °C and 120 min, the moisture content is found to be 1.15% (w.b.. Volatile content in the lodgepole pine decreased from about 80% to about 45%, and ash content increased from 0.77% to about 1.91% at 270 °C and 120 min. The hydrogen, oxygen, and sulfur content decreased to 3%, 28.24%, and 0.01%, whereas the carbon content and higher heating value increased to 68.86% and 23.67 MJ/kg at 270 °C and 120 min. Elemental ratio of hydrogen to carbon and oxygen to carbon (H/C and O/C calculated at 270 °C and a 120-min residence time were about 0.56 and 0.47. Based on this study, it can be concluded that higher torrefaction temperatures ≥230 °C and residence time ≥15 min influence the proximate, ultimate, and energy properties of ground lodgepole pine.

Recent advances in drying and dehydration of fruits and vegetables: a review.

Science.gov (United States)

Sagar, V R; Suresh Kumar, P

2010-01-01

Fruits and vegetables are dried to enhance storage stability, minimize packaging requirement and reduce transport weight. Preservation of fruits and vegetables through drying based on sun and solar drying techniques which cause poor quality and product contamination. Energy consumption and quality of dried products are critical parameters in the selection of drying process. An optimum drying system for the preparation of quality dehydrated products is cost effective as it shortens the drying time and cause minimum damage to the product. To reduce the energy utilization and operational cost new dimensions came up in drying techniques. Among the technologies osmotic dehydration, vacuum drying, freeze drying, superheated steam drying, heat pump drying and spray drying have great scope for the production of quality dried products and powders.

Environmental microbiology as related to planetary quarantine. [synergetic effect of heat and radiation

Science.gov (United States)

Pflug, I. J.

1973-01-01

The mechanistic basis of the synergetic effect of combined heat and radiation on microbial destruction was analyzed and results show that radiation intensity, temperature, and relative humidity are the determining factors. Dry heat resistance evaluation for selected bacterial spore crops indicates that different strains of Bacillus stearothermophilus demonstrate marked differences in resistance. Preliminary work to determine the effects of storage time, suspending medium, storage temperature and spore crop cleaning procedures on dry heat survival characteristics of Bacillus subtilis var. Niger, and dry heat resistance of natural microflora in soil particles is also reported.

Post-blink tear film dynamics in healthy and dry eyes during spontaneous blinking.

Science.gov (United States)

Szczesna-Iskander, Dorota H

2018-01-01

The aim was to investigate the dynamics of post-blink tear film leveling in natural blinking conditions (NBC) for healthy subjects and those diagnosed with dry eye syndrome (DES) and to relate this phase to the tear film surface quality (TFSQ) before the following blink. The study included 19 healthy persons and 10 with dry eye, grouped according to symptoms and signs observed during examination. Lateral shearing interferometry was used to examine TFSQ. Post-blink tear film dynamics was modeled by an exponential function, characterized by the decay parameter b, and a constant, describing the level of the stabilized TFSQ. Pre-next-natural-blink TFSQ dynamics was modeled with a linear trend, described by a parameter A. The post-blink tear film dynamics reached its plateau at a significantly (P = 0.006) lower level in the normal tear film group than in the dry eye group. The median exponential decay parameter b was statistically significantly higher for the control group than for the DES group, P = 0.026. The parameter b calculated for each interblink interval was significantly correlated with the corresponding parameter A (Spearman's R = 0.35; P film fluorescein break-up time for each subject was also found (R = 0.41, P = 0.029). Significantly faster leveling of post-natural-blink tear film was observed in the group with DES than in healthy eyes. This dynamic was correlated with the pre-next-natural-blink TFSQ and tear film stability. The results of this pilot study support previous works that advocate the importance of polar lipids in the mechanism of tear film lipid spreading. Copyright © 2017 Elsevier Inc. All rights reserved.

Does Spontaneous Favorability to Power (vs. Universalism) Values Predict Spontaneous Prejudice and Discrimination?

Science.gov (United States)

Souchon, Nicolas; Maio, Gregory R; Hanel, Paul H P; Bardin, Brigitte

2017-10-01

We conducted five studies testing whether an implicit measure of favorability toward power over universalism values predicts spontaneous prejudice and discrimination. Studies 1 (N = 192) and 2 (N = 86) examined correlations between spontaneous favorability toward power (vs. universalism) values, achievement (vs. benevolence) values, and a spontaneous measure of prejudice toward ethnic minorities. Study 3 (N = 159) tested whether conditioning participants to associate power values with positive adjectives and universalism values with negative adjectives (or inversely) affects spontaneous prejudice. Study 4 (N = 95) tested whether decision bias toward female handball players could be predicted by spontaneous attitude toward power (vs. universalism) values. Study 5 (N = 123) examined correlations between spontaneous attitude toward power (vs. universalism) values, spontaneous importance toward power (vs. universalism) values, and spontaneous prejudice toward Black African people. Spontaneous positivity toward power (vs. universalism) values was associated with spontaneous negativity toward minorities and predicted gender bias in a decision task, whereas the explicit measures did not. These results indicate that the implicit assessment of evaluative responses attached to human values helps to model value-attitude-behavior relations. © 2016 The Authors. Journal of Personality Published by Wiley Periodicals, Inc.

Atmospheric Circulations of Rocky Planets as Heat Engines

Science.gov (United States)

Koll, D. D. B.

2017-12-01

Rocky planets are extremely common in the galaxy and include Earth, Mars, Venus, and hundreds of exoplanets. To understand and compare the climates of these planets, we need theories that are general enough to accommodate drastically different atmospheric and planetary properties. Unfortunately, few such theories currently exist.For Earth, there is a well-known principle that its atmosphere resembles a heat engine - the atmosphere absorbs heat near the surface, at a hot temperature, and emits heat to space in the upper troposphere, at a cold temperature, which allows it to perform work and balance dissipative processes such as friction. However, previous studies also showed that Earth's hydrological cycle uses up a large fraction of the heat engine's work output, which makes it difficult to view other atmospheres as heat engines.In this work I extend the heat engine principle from Earth towards other rocky planets. I explore both dry and moist atmospheres in an idealized general circulation model (GCM), and quantify their work output using entropy budgets. First, I show that convection and turbulent heat diffusion are important entropy sources in dry atmospheres. I develop a scaling that accounts for its effects, which allows me to predict the strength of frictional dissipation in dry atmospheres. There are strong parallels between my scaling and so-called potential intensity theory, which is a seminal theory for understanding tropical cyclones on Earth. Second, I address how moisture affects atmospheric heat engines. Moisture modifies both the thermodynamic properties of air and releases latent heat when water vapor condenses. I explore the impact of both effects, and use numerical simulations to explore the difference between dry and moist atmospheric circulations across a wide range of climates.

THE LINE FOR PRODUCTION OF DRIED APPLES, PEARS, CARROTS, PUMPKIN AND CHIPS

Directory of Open Access Journals (Sweden)

G. V. Kalashnikov

2015-01-01

Full Text Available The line is intended for processing of fruit and vegetable raw materials and receiving dried apples, pears, carrots, pumpkins and the fruit-and-vegetable of chips. The line solves problems of improvement of quality of a ready-made product and thermal production efficiency due to more rational alternation of the technological modes of a moisture increment and dehumidification with high extent of use of an energy potential of the heat carrier, use of the inert heat carrier (steam identical by the form for technological thermal processes, decrease in specific energy consumption and metal consumption, and also an intensification of moisture evaporation and creation of the compact multipurpose technological line for production of fruit and vegetable products with the expanded range. The technological production line of dried apples, pears, carrots, pumpkin and fruit and vegetable chips contains the jet washer, the inspection conveyor, the size grader, the car for removal of a seed nest and the device are sharp fruits and vegetables on plates, the sulfiter, the dryer and the packing automatic packing machine. Thus the line contains the combined toroidal device for heatmoisture of handling continuous action divided into sections: section of heating of raw materials, section of convective drying, section of preliminary hydration, which is located between microwave drying sections, and the section of cooling of the dried-up product intended for bringing a product to final readiness. The equipment complex from the drum car with the washing block and multipurpose installation with crushing of raw materials and office of sunflower seeds taking into account raw materials type is provided in lines. Are used recirculation a contour, the heating of the initial raw material fulfilled after drying of pairs and a condensate in the closed contour for creation energy-saving of the "know-how" of a ready product. The line represents modular blocks and is recustomized

Experimental investigation of a solar dryer with natural convective heat flow

Energy Technology Data Exchange (ETDEWEB)

Gbaha, P.; Yobouet Andoh, H.; Kouassi Saraka, J. [Laboratoire d' Energies d' Energies Nouvelles et Renouvelables, Institut National Polytechnique Felix Houphoeuet-Boigny, B.P. 1526 Yamoussoukro (Ivory Coast); Kamenan Koua, B.; Toure, S. [Laboratoire d' Energie Solaire, Universite de Cocody, 22 B.P.: 582, Abidjan 22 (Ivory Coast)

2007-09-15

A direct type natural convection solar dryer is designed. It is constructed in local materials (wood, blades of glass, metals) then tested experimentally in foodstuffs drying (cassava, bananas, mango). It is about an experimental approach which consists in analyzing the behavior of the dryer. The study relates mainly kinetics and establishment of drying heat balances. The influence of significant parameters governing heat and mass transfers, such as solar incident radiation, drying air mass flow and effectiveness, is analyzed in order to evaluate its thermal performances. Experimental data can be represented by empirical correlations of the form M(t)=M{sub i}exp(-kt) for representation of drying process. The resolution of these drying equations makes-possible to predict total drying time of each product. Moreover, this drying process allows to reduce the moisture content of cassava and sweet banana approximately to 80% in 19 and 22 h, respectively to reach the safety threshold value of 13%. This value permits the conservation of these products about one year without deterioration. The determination of parameters, like ambient temperature, drying chamber temperature, drying air mass flow and incident heat fluxes, allow to predict the drying effectiveness for modeling and refining the dimensioning of the elaborate prototype. (author)

Starch nanoparticles resulting from combination of dry heating under mildly acidic conditions and homogenization.

Science.gov (United States)

Kim, Jong Hun; Kim, Jiyeon; Park, Eun Young; Kim, Jong-Yea

2017-07-15

To modify starch granular structure, normal maize starch was subjected to dry heating with various amounts of 1.0M HCl (1.2, 1.4 or 1.6mL) and different treatment times (2, 4 or 8h). For all reaction conditions, at least 80% of the starch substance was recovered, and amylose and amylopectin B1 chains were preferentially cleaved. As acidic condition and/or treatment time increased, the treated granules were readily fragmented by homogenization. The treatment appeared to alter short-range crystalline structure (FT-IR), but long-range crystalline structure (XRD) remained intact. Homogenization for 60min fragmented the treated starch granules (subjected to reaction condition of 1.4mL/4h, 1.6mL/2h, and 1.6mL/4h) into nanoparticles consisting of individual platelet-like and spherical particles with diameters less than 100nm. However, the fragmentation caused obvious damage in the long-range crystalline structure of starch nanoparticles, while the short-range chain associations remained relatively intact. Copyright © 2017 Elsevier Ltd. All rights reserved.

Safety Aspects of Long Term Spent Fuel Dry Storage

International Nuclear Information System (INIS)

Botsch, Wolfgang; Smalian, S.; Hinterding, P.; Drotleff, H.; Voelzke, H.; Wolff, D.; Kasparek, E.

2014-01-01

As a consequence of the lack of a final repository for spent nuclear fuel (SF) and high level waste (HLW), long term interim storage of SF and HLW will be necessary. As with the storage of all radioactive materials, the long term storage of SF and HLW must conform to safety requirements. Safety aspects such as safe enclosure of radioactive materials, safe removal of decay heat, sub-criticality and avoidance of unnecessary radiation exposure must be achieved throughout the complete storage period. The implementation of these safety requirements can be achieved by dry storage of SF and HLW in casks as well as in other systems such as dry vault storage systems or spent fuel pools, where the latter is neither a dry nor a passive system. After the events of Fukushima, the advantages of passively and inherently safe dry storage systems have become more obvious. In Germany, dry storage of SF in casks fulfils both transport and storage requirements. Mostly, storage facilities are designed as concrete buildings above the ground; one storage facility has also been built as a rock tunnel. In all these facilities the safe enclosure of radioactive materials in dry storage casks is achieved by a double-lid sealing system with surveillance of the sealing system. The safe removal of decay heat is ensured by the design of the storage containers and the storage facility, which also secures to reduce the radiation exposure to acceptable levels. TUV and BAM, who work as independent experts for the competent authorities, inform about spent fuel management and issues concerning dry storage of spent nuclear fuel, based on their long experience in these fields. All relevant safety issues such as safe enclosure, shielding, removal of decay heat and sub-criticality are checked and validated with state-of-the-art methods and computer codes before the license approval. In our presentation we discuss which of these aspects need to be examined closer for a long term interim storage. It is shown

Future needs for dry or peak shaved dry/wet cooling and significance to nuclear power plants. Final report

International Nuclear Information System (INIS)

Clukey, H.V.; McNelly, M.J.; Mitchell, R.C.

1976-02-01

U.S. requirements for uncommitted nuclear installations in water scarce areas that might require dry cooling tower systems are minimal through the year 2000 (6 to 23 GWe). In these areas it appears that peak-shaved dry/wet cooling systems are more attractive than all-dry tower cooling unless water costs were to approach the high level of several cents per gallon. The differential cooling system evaluated cost of peak-shaved dry/wet cooling systems above wet towers is typically $20 to $30/kWe for steam turbines; whereas, dry towers can represent an incremental burden of as much as $80/kWe. Gas turbine (Brayton Cycle) systems show similar benefits from an evaporative heat sink to those for steam turbine cycles--lower cooling system evaluated costs for peak-shaved dry/wet cooling systems than for conventional wet towers. These cooling system cost differentials do not reflect total costs for Brayton Cycle gas turbine plants. Together these added costs and uncertainties may substantially exceed the dollar incentives available for development of the Brayton Cycle for power generation needs for water deficient sites

Development of a compact freeze vacuum drying for jelly fish (Schypomedusae)

Science.gov (United States)

Alhamid, M. Idrus; Yulianto, M.; Nasruddin

2012-06-01

A new design of a freeze vacuum drying with internal cooling and heater from condenser's heat loss was built and tested. The dryer was used to dry jelly fish (schypomedusae), to study the effect of drying parameters such as the temperature within the drying chamber on mass losses (evaporation) during the freezing stage and the moisture ratio at the end of the drying process. The midili thin layer mathematical drying model was used to estimate and predict the moisture ratio curve based on different drying chamber temperatures. This experiment shows that decreasing the drying chamber temperature with constant pressure results in less mass loss during the freezing stage Drying time was reduced with an increase in drying temperature. Decreasing the drying chamber temperature results in lower pressure saturation of the material has no effect of drying chamber pressure on mass transfer.

Thermoelectric Powered Wireless Sensors for Dry-Cask Storage

Science.gov (United States)

Carstens, Thomas Alan

This study focuses on the development of self-powered wireless sensors. These sensors can be used to measure key parameters in extreme environments; e.g., temperature monitoring for spent nuclear fuel during dry-cask storage. This study has developed a design methodology for these self-powered monitoring systems. The main elements that constitute this work consist of selecting and testing a power source for the wireless sensor, determination of the attenuation of the wireless signal, and testing the wireless sensor circuitry in an extreme environment. OrigenArp determined the decay heat and gamma/neutron source strength of the spent fuel throughout the service life of the dry-cask. A first principles analysis modeled the temperatures inside the dry-cask. A finite-element heat transfer code calculated the temperature distribution of the thermoelectric and heat sink. The temperature distributions determine the power produced by the thermoelectric. It was experimentally verified that a thermoelectric generator (HZ-14) with a DC/DC converter (Linear Technology LTC3108EDE) can power a transceiver (EmbedRF) at condition which represent prototypical conditions throughout and beyond the service life of the dry-cask. The wireless sensor is required to broadcast with enough power to overcome the attenuation from the dry-cask. It will be important to minimize the attenuation of the signal in order to broadcast with a small transmission power. To investigate the signal transmission through the dry-cask, CST Microwave Studio was used to determine the scattering parameter S2,1 for a horizontal dry-cask. Important parameters that can influence the transmission of the signal are antenna orientation, antenna placement, and transmission frequency. The thermoelectric generator, DC/DC converter, and transceiver were exposed to 60Co gamma radiation (exposure rate170.3 Rad/min) at the University of Wisconsin Medical Radiation Research Center. The effects of gamma radiation on the

Impact of Pretreatment and Drying Methods on Quality Attributes of Onion Shreds

Directory of Open Access Journals (Sweden)

Nihar R. Sahoo

2015-01-01

Full Text Available Experiments were conducted on dry untreated onion shreds (2 mm thickness or treated with salt (5 % solution and potassium metabisulphite (0.5 % solution in convective drier at 50 °C ((46±4 % relative humidity (RH, 55 °C ((35±4 % RH, 60 °C ((28±4 % RH and 65 °C ((20±4 % RH, heat pump-assisted convective drier at 35 °C ((32±2 % RH, 40 °C ((26±2 % RH, 45 °C ((19±2 % RH and 50 °C ((15±2 % RH and microwave-assisted convective drier at four microwave power levels, i.e. 120, 240, 360 and 480 W. The quality parameters of the dried onion shreds, namely rehydration ratio, colour diff erence, pyruvic and ascorbic acid contents and sensory scores were evaluated. The quality of dehydrated onion shreds was observed to be comparatively better when treated in heat pump drier at 50 °C, followed by that in microwave-assisted convective drier at 240 W and 50 °C, and last in convective drier at 60 °C. The onion shreds pretreated with potassium metabisulphite retained better colour of the dried product irrespective of drying methods. Therefore, heat pump drying may be recommended as one of the best drying methods for onion shreds, because it maintains the fi nal product quality, which has practical importance for the food industry.

Development and Validation of a Simulation Model for the Temperature Field during High-Frequency Heating of Wood

Directory of Open Access Journals (Sweden)

Haojie Chai

2018-06-01

Full Text Available In the process of applying high-frequency heating technology to wood drying, controlling the material temperature affects both drying speed and drying quality. Therefore, research on the heat transfer mechanism of high-frequency heating of wood is of great significance. To study the heat transfer mechanism of high-frequency heating, the finite element method was used to establish and solve the wood high-frequency heating model, and experimental verification was carried out. With a decrease in moisture content, the heating rate decreased, then increased, and then decreased again. There was no obvious linear relationship between the moisture content and heating rate; the simulation accuracy of the heating rate was higher in the early and later drying stages and slightly lower near the fiber saturation point. For the central section temperature distribution, the simulation and actual measurement results matched poorly in the early drying stage because the model did not fully consider the differences in the moisture content distribution of the actual test materials. In the later drying stage, the moisture content distribution of the test materials became uniform, which was consistent with the model assumptions. Considering the changes in heating rate and temperature distribution, the accuracy of the model is good under the fiber saturation point, and it can be used to predict the high-frequency heating process of wood.

Thermal characterisation of compact heat exchangers for air heating and cooling in electric vehicles

International Nuclear Information System (INIS)

Torregrosa-Jaime, B.; Corberán, J.M.; Payá, J.; Delamarche, J.L.

2017-01-01

The use of air conditioning in all-electric cars reduces their driving range by 33% in average. With the purpose of reducing the energy consumption of the vehicle and optimising the performance of the batteries, the mobile air-conditioning can be integrated with the temperature control system of the powertrain by means of a coolant loop. In such layouts, the air-to-coolant heat exchangers must operate efficiently in both air heating and cooling modes. Dynamic simulation tools comprising the entire thermal system are essential to assess its performance. In this context, fast but accurate models of the system components are required. This paper presents the thermal characterisation of a commercial compact louvered-fin flat-tube heat exchanger (heater core) for this novel application, based on an experimental campaign comprising 279 working points that reflect real air-conditioning (heating and cooling) working conditions. A general methodology to fit a single correlation of the global heat transfer coefficient for both dry and wet working conditions is explained. The semiempirical correlation developed is employed in a single-node model of the heat exchanger that requires minimal computation time. The present model predicts the heat transfer rate with an average deviation of 3.5% in the cases with dehumidification and 1.9% in the cases when the heat exchanger remains dry.

Affordable Hybrid Heat Pump Clothes Dryer

Energy Technology Data Exchange (ETDEWEB)

TeGrotenhuis, Ward E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Butterfield, Andrew [Jabil, St. Petersburg, FL (United States); Caldwell, Dustin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Crook, Alexander [Jabil, St. Petersburg, FL (United States)

2016-06-30

This project was successful in demonstrating the feasibility of a step change in residential clothes dryer energy efficiency by demonstrating heat pump technology capable of 50% energy savings over conventional standard-size electric dryers with comparable drying times. A prototype system was designed from off-the-shelf components that can meet the project’s efficiency goals and are affordable. An experimental prototype system was built based on the design that reached 50% energy savings. Improvements have been identified that will reduce drying times of over 60 minutes to reach the goal of 40 minutes. Nevertheless, the prototype represents a step change in efficiency over heat pump dryers recently introduced to the U.S. market, with 30% improvement in energy efficiency at comparable drying times.

Electrostatic process for a heat pump with spontaneous flow; Procede electrostatique de pompe a chaleur a ecoulement spontane

Energy Technology Data Exchange (ETDEWEB)

Brochet, J.L.

2001-07-01

This document describes a new type of high-performance electrostatic gas heat pump. An electrical field is created at the surface of the hot plate (the 'electrostatic' plate) which polarizes and attracts the gas molecules. The thermodynamic principle and the technical aspects of this invention are described, together with some specific applications (thermoelectric converter with a unique heat source, plant for power and fresh water production from seawater). (J.S.)

Driving factors of the communities of phytophagous and predatory mites in a physic nut plantation and spontaneous plants associated.

Science.gov (United States)

Cruz, Wilton P; Sarmento, Renato A; Teodoro, Adenir V; Neto, Marçal P; Ignacio, Maíra

2013-08-01

Seasonal changes in climate and plant diversity are known to affect the population dynamics of both pests and natural enemies within agroecosystems. In Brazil, spontaneous plants are usually tolerated in small-scale physic nut plantations over the year, which in turn may mediate interactions between pests and natural enemies within this agroecosystem. Here, we aimed to access the influence of seasonal variation of abiotic (temperature, relative humidity and rainfall) and biotic (diversity of spontaneous plants, overall richness and density of mites) factors on the communities of phytophagous and predatory mites found in a physic nut plantation and its associated spontaneous plants. Mite sampling was monthly conducted in dicotyledonous and monocotyledonous leaves of spontaneous plants as well as in physic nut shrubs over an entire year. In the dry season there was a higher abundance of phytophagous mites (Tenuipalpidae, Tarsonemidae and Tetranychidae) on spontaneous plants than on physic nut shrubs, while predatory mites (Phytoseiidae) showed the opposite pattern. The overall density of mites on spontaneous plants increased with relative humidity and diversity of spontaneous plants. Rainfall was the variable that most influenced the density of mites inhabiting physic nut shrubs. Agroecosystems comprising spontaneous plants associated with crops harbour a rich mite community including species of different trophic levels which potentially benefit natural pest control due to increased diversity and abundance of natural enemies.

OSCILLATING MODE OF TOPINAMBUR TUBERS DRYING

Directory of Open Access Journals (Sweden)

A. V. Golubkivich

2015-01-01

Full Text Available Specifics of a chemical composition of tubers and green material of a topinambur (Helianthus tuberosus, high efficiency and ecological plasticity, profitability of growing, biotechnological potential of use enable to identify a topinambur as a of high-energy cultures of the future. High moisture of various topinambur parts, features of the mechanism of a heat and mass transfer set a problem of search of the new drying methods promoting to increase dehydration efficiency and produce a quality product. A method of calculation of duration of the oscillating mode of topinambur tubers drying in a dense layer is worked out. The topinambur tubers cut on cubes with the side of 6 mm were taken as object of researches. Researches were conducted in the setting of various drying modes: two experiences at the oscillating mode with height of a material layer of 0.07 m and 0.17 m; and also as a check experiment was material drying at a constant temperature of the drying agent. Duration of the oscillating mode of topinambur tubers drying was calculated on their basis of received curves of changes of moisture content at various modes of drying. Estimate indicators were confirmed with experimental data. Results of determination of duration of the oscillating modes of topinambur tubers drying proved that efficiency of the oscillating modes is 18 percent higher, than at control experiment.

Dry Air Cooler Modeling for Supercritical Carbon Dioxide Brayton Cycle Analysis

Energy Technology Data Exchange (ETDEWEB)

Moisseytsev, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Lv, Q. [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-07-28

Modeling for commercially available and cost effective dry air coolers such as those manufactured by Harsco Industries has been implemented in the Argonne National Laboratory Plant Dynamics Code for system level dynamic analysis of supercritical carbon dioxide (sCO₂) Brayton cycles. The modeling can now be utilized to optimize and simulate sCO₂ Brayton cycles with dry air cooling whereby heat is rejected directly to the atmospheric heat sink without the need for cooling towers that require makeup water for evaporative losses. It has sometimes been stated that a benefit of the sCO₂ Brayton cycle is that it enables dry air cooling implying that the Rankine steam cycle does not. A preliminary and simple examination of a Rankine superheated steam cycle and an air-cooled condenser indicates that dry air cooling can be utilized with both cycles provided that the cycle conditions are selected appropriately

Effect of Heat Drawing Process on Mechanical Properties of Dry-Jet Wet Spun Fiber of Linear Low Density Polyethylene/Carbon Nanotube Composites

Directory of Open Access Journals (Sweden)

Jong Won Kim

2017-01-01

Full Text Available Polyethylene is one of the most commonly used polymer materials. Even though linear low density polyethylene (LLDPE has better mechanical properties than other kinds of polyethylene, it is not used as a textile material because of its plastic behavior that is easy to break at the die during melt spinning. In this study, LLDPE fibers were successfully produced with a new approach using a dry-jet wet spinning and a heat drawing process. The fibers were filled with carbon nanotubes (CNTs to improve the strength and reduce plastic deformation. The crystallinity, degree of orientation, mechanical properties (strength to yield, strength to break, elongation at break, and initial modulus, electrical conductivity, and thermal properties of LLDPE fibers were studied. The results show that the addition of CNTs improved the tensile strength and the degree of crystallinity. The heat drawing process resulted in a significant increase in the tensile strength and the orientation of the CNTs and polymer chains. In addition, this study demonstrates that the heat drawing process effectively decreases the plastic deformation of LLDPE.

A quantitative evaluation of dry-sensor electroencephalography

Science.gov (United States)

Uy, E. Timothy

Neurologists, neuroscientists, and experimental psychologists study electrical activity within the brain by recording voltage fluctuations at the scalp. This is electroencephalography (EEG). In conventional or "wet" EEG, scalp abrasion and use of electrolytic paste are required to insure good electrical connection between sensor and skin. Repeated abrasion quickly becomes irritating to subjects, severely limiting the number and frequency of sessions. Several groups have produced "dry" EEG sensors that do not require abrasion or conductive paste. These, in addition to sidestepping the issue of abrasion, promise to reduce setup time from about 30 minutes with a technician to less than 30 seconds without one. The availability of such an instrument would (1) reduce the cost of brain-related medical care, (2) lower the barrier of entry on brain experimentation, and (3) allow individual subjects to contribute substantially more data without fear of abrasion or fatigue. Accuracy of the EEG is paramount in the medical diagnosis of epilepsy, in experimental psychology and in the burgeoning field of brain-computer interface. Without a sufficiently accurate measurement, the advantages of dry sensors remain a moot point. However, even after nearly a decade, demonstrations of dry EEG accuracy with respect to wet have been limited to visual comparison of short snippets of spontaneous EEG, averaged event-related potentials or plots of power spectrum. In this dissertation, I propose a detailed methodology based on single-trial EEG classification for comparing dry EEG sensors to their wet counterparts. Applied to a set of commercially fabricated dry sensors, this work reveals that dry sensors can perform as well their wet counterparts with careful screening and attention to the bandwidth of interest.

Quasi-steady temperature gradient metamorphism in idealized, dry snow

International Nuclear Information System (INIS)

Christon, M.

1994-01-01

A three-dimensional model for heat and mass transport in microscale ice lattices of dry snow is formulated consistent with conservation laws and solid-vapor interface constraints. A finite element model that employs continuous mesh deformation is developed, and calculation of the effective diffusion rates in snow, metamorphosing under a temperature gradient, is performed. Results of the research provide basic insight into the movement of heat and water vapor in seasonal snowcovers. Agreement between the numerical results and measured data of effective thermal conductivity is excellent. The enhancement to the water vapor diffusion rate in snow is bracketed in the range of 1.05--2.0 times that of water vapor in dry air

太阳能热泵联合干燥技术在农副产品中应用与展望%Application and Prospect on the Technology of Combined Drying for Solar Energy and Heat Pump in Agricultural and Sideline Products

Institute of Scientific and Technical Information of China (English)

白旭升; 李保国; 朱传辉; 苏树强

2017-01-01

Drying was widely used in processing industries such as industry of agriculture, food and aquatic products. A wide range of solar energy can be taken full advantage of by the combined drying for solar energy and heat pump devices, meanwhile some problems of solar energy for the instability, easily affected by weather and other factors would be solved and it had broad application prospects. In addition, the combined drying for solar energy and heat pump devices were gradually promoted and applied because of its energy saving, improving the quality of the dried product and other factors in drying industry. The purpose of this paper is to comprehensively expound the drying mode of combined drying for solar energy and heat pump, and its application situation on the drying industries such as timber, agricultural products was reviewed. Besides, the research and development trend of combined drying for solar energy and heat pump were put forward. It can be used to direct the selection of drying technology.%干燥技术被广泛应用于农业、食品和水产品等加工领域.太阳能热泵联合干燥装置既能充分利用广泛的太阳能资源,同时又能解决太阳能不稳定、易受天气影响等因素,具有广阔的应用前景;又因其节能,改善干燥产品品质等因素,而逐渐被干燥行业所推广应用.阐述了太阳能热泵联合干燥的工作模式,综述了太阳能热泵联合干燥在木材、农副产品等行业的应用现状,并提出了太阳能热泵联合干燥技术的现存问题和发展展望,可为干燥技术的选择提供参考.