Journal articles on the topic 'Contact water heater'
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1
Paik, S. W., K. D. Kihm, S. P. Lee, and D. M. Pratt. "Spatially and Temporally Resolved Temperature Measurements for Slow Evaporating Sessile Drops Heated by a Microfabricated Heater Array." Journal of Heat Transfer 129, no. 8 (October 27, 2006): 966–76. http://dx.doi.org/10.1115/1.2728904.
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The spatially and temporally resolved evaporation phenomena of a slowly evaporating water droplet are investigated using a microfabricated gold heater array consisting of 32 linear heater elements (100 μm wide and 15 mm long, each). Each of the gold microheater elements works both as a temperature sensor and as a heater. The experiment is performed under a constant voltage mode to examine the spatially resolved temperature history of the droplet contact surface for a period starting at initial contact with the heater and lasting to the point of complete dryout. The raw data obtained from the linear array have been tomographically deconvolved so that the radial temperature profile can be determined assuming a circular droplet contact surface.
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HONG, HIKI, JONG HYUN KIM, JAE DONG CHUNG, HIROYUKI KUMANO, and DOUGLAS REINDL. "FREEZE PROTECTION METHOD USING HOT WATER FOR PASSIVE SOLAR WATER HEATING SYSTEM." International Journal of Air-Conditioning and Refrigeration 20, no. 04 (December 2012): 1250021. http://dx.doi.org/10.1142/s2010132512500216.
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In the present work, a new freeze protection method is introduced with intended applications for passive solar water heaters. Though electro-thermal wire heat tracing is popularly used to prevent freezing with subsequent risk of burst, this approach is problematic due to resistance heater failure and excessive electric power consumption. In the experimental device, hot water in thermal storage tank is used to heat the outlet pipe from the tank when the surface temperature of the pipe falls lower than a pre-determined set point. The cold water pipe to the thermal storage tank is installed in direct contact with the hot water pipe, controlling its temperature by conduction with the hot water pipe.
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Marchenko, G. S., and V. A. Makarenko. "SYSTEMS OF AUTONOMOUS HEATING WITH THE USE OF CONTACT WATER HEATERS." Energy Technologies & Resource Saving, no. 2 (June 20, 2019): 11–15. http://dx.doi.org/10.33070/etars.2.2019.02.
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The article proposed technical solutions for the use of a highly efficient contact water heater for heating systems and hot water supply for civil and industrial buildings. The schemes of the heating complex, separate for heating systems, separate for hot water systems and their description are given. The calculations of the economic efficiency of the contact method of heating are given. The expediency of using water contact heating units is shown. Bibl. 5, Fig. 5.
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Unal, C., V. Daw, and R. A. Nelson. "Unifying the Controlling Mechanisms for the Critical Heat Flux and Quenching: The Ability of Liquid to Contact the Hot Surface." Journal of Heat Transfer 114, no. 4 (November 1, 1992): 972–82. http://dx.doi.org/10.1115/1.2911909.
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We investigated the hypothesis that the critical heat flux (CHF) occurs when some point on a heated surface reaches a temperature high enough that liquid can no longer maintain contact at that point, resulting in a gradual but continuous increase in the overall surface temperature for most power-controlled systems. This hypothesis unifies the occurrence of the CHF with the quenching of hot surfaces by relating them to the same concept: the ability of a liquid to contact a hot surface, generally defined as some fraction of the liquid’s homogeneous nucleation temperature, depending on the contact angle. The proposed hypothesis about the occurrence of the CHF is investigated through a study of the boiling mechanism of the second transition region of nucleate pool boiling of water on copper. An idealized two-dimensional transient conduction heat transfer model was developed to investigate the heat transfer mechanism. The initial macrolayer thickness on the dry portion of the heater, in the second transition region, was found to be bounded between 0 and 11 μm. The radius of the dry patch varied from 15 to 23 mm (60 and 92 percent of the heater radius, respectively) for initial macrolayer thicknesses of 0 and 11 μm, respectively. The results indicated that the critical liquid-solid contact temperature at the onset of CHF (the surface temperature at the center of the dry patch) must be lower than the homogeneous nucleation temperature of the liquid for the pool boiling of water on a clean horizontal surface. The liquid-solid contact temperature was dependent on the initial dry patch liquid macrolayer thickness, varying from 180°C to 157°C for initial macrolayer thicknesses of 0 and 11 μm, respectively. Independent assessment of these values shows good agreement with extrapolated contact temperature data at the onset of film boiling. This indicates that the mechanism for the occurrence of the CHF could be similar to the mechanism generally accepted for the quenching of the hot surfaces. Further study of this mechanism to understand better the observed trends in other experimental results show qualitative agreement with those results. These include a significant decrease in the radius of the dry patch to 4 mm (16 percent of the heater radius) when the thermal conductivity of the heater was decreased to that corresponding to nickel. When the thickness of a copper heater was decreased from 10 mm (representing an infinitely thick medium) to 0.1 mm, a dry patch radius of 2.25 mm (9 percent of the heater radius) was found to be sufficient for the temperature at the center of the dry patch to reach the critical contact temperature. These comparisons are felt to provide some understanding as to why the second transition region has been observed only in limited cases.
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Wang, C. H., and V. K. Dhir. "On the Gas Entrapment and Nucleation Site Density During Pool Boiling of Saturated Water." Journal of Heat Transfer 115, no. 3 (August 1, 1993): 670–79. http://dx.doi.org/10.1115/1.2910738.
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A model to describe the effect of wettability on nucleation site density is presented. First, from Helmholtz free energy analysis, a criterion for the entrapment condition in a uniform temperature field is developed. Second, the stability condition of preexisting gas/vapor nuclei during the heating process and the minimum superheat required to initiate nucleation are determined. The prediction of the entrapment condition and the incipient temperature are consistent with the experimental observations made on surfaces having naturally existing cavities. Third, a naturally formed cavity on a heater surface is modeled as a spherical cavity. The cumulative active nucleation site density for a specified contact angle is expressed in terms of the cumulative density of cavities existing on the surface as Na = Pas · Nas where Nas is the heater surface cumulative cavity density with cavity mouth angles less than a specified value and Pas is a function of contact angle and cavity mouth angle. The model successfully predicts active site densities for different contact angles.
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Muriana, P. M., T. Bowser, C. Davidson, M. Tilahun, and D. E. Gibbs. "‘Flash pasteurization’ of contaminated streams using a direct contact gas-fired water heater." Food Microbiology 20, no. 1 (February 2003): 77–82. http://dx.doi.org/10.1016/s0740-0020(02)00100-4.
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Jotshi, C. K., D. Y. Goswami, J. F. Klausner, and S. Malakar. "A water heater using very high-temperature storage and variable thermal contact resistance." International Journal of Energy Research 25, no. 10 (2001): 891–98. http://dx.doi.org/10.1002/er.727.
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Marchuk, Igor, Andrey Karchevsky, Anton Surtaev, and Oleg Kabov. "Heat Flux at the Surface of Metal Foil Heater under Evaporating Sessile Droplets." International Journal of Aerospace Engineering 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/391036.
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Evaporating water drops on a horizontal heated substrate were investigated experimentally. The heater was made of a constantan foil with the thickness of 25 μm and size of 42 × 35 mm2. The temperature of the bottom foil surface was measured by the infrared (IR) camera. To determine the heat flux density during evaporation of liquid near the contact line, the Cauchy problem for the heat equation was solved using the temperature data. The maximum heat flux density is obtained in the contact line region and exceeds the average heat flux density from the entire foil surface by the factor of 5–7. The average heat flux density in the region wetted by the drop exceeds the average heat flux density from the entire foil surface by the factor of 3–5. This fact is explained by the heat influx from the foil periphery to the drop due to the relatively high heat conductivity coefficient of the foil material and high evaporation rate in the contact line region. Heat flux density profiles for pairs of sessile droplets are also investigated.
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Rajan, V. S. V., and R. Tipman. "A Method for Improving the Quality of Bituminous Froth From Water Extraction of Oil Sands." Journal of Energy Resources Technology 114, no. 4 (December 1, 1992): 261–66. http://dx.doi.org/10.1115/1.2905951.
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Bituminous froths produced from the water extraction of oil sands contain significant quantities of sand and water which must be removed prior to upgrading the bitumen to synthetic crude oil. This paper presents a summary of the study of a simple twostep process for removing most of the solid and water contaminants from the bituminous froth. Low-quality froths containing 10–30 percent bitumen at temperatures of 40–70°C were improved in quality to 50–60 percent bitumen by heating the raw froth to ~ 90°C and settling the product in a gravity settler. The gravity settling vessel incorporated unique features for the introduction of the hot froth into the vessel. Two types of froth heaters were tested: a column heater containing a structured grid packing which used live steam injection, and a shell and tube heat exchanger. Heat transfer data were obtained for both types of heaters in the range of froth flow conditions available in the pilot plant. There was no apparent difference between the two heating modes in terms of the froth quality improvement, but the direct contact heater had the benefit of deaerating the froth. Evaluation of the separation efficiency showed that the gravity separation vessel design performed very well, and hence was incorporated into a commercial froth cleaning plant design. The bitumen separation efficiency was the best for froths containing about 20 percent bitumen. There was no apparent improvement in the froth quality for froths containing over 65 percent bitumen.
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Liu, Sheng Wang, Wei Fang Zhang, and Qing Yun Tang. "An Experimental Setup to Test Thermal Contact Conductance Across Solid/Solid Interface." Advanced Materials Research 291-294 (July 2011): 1293–96. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.1293.
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This article describes an experimental setup to measure the TCC between interfaces of two contact solid materials. This apparatus consists of loading and load bearing subsystem, water-cooling subsystem, heating subsystem, temperature measurement and control subsystem and thermal insulation subsystem. A new kind of design scheme of the compensation heater is put forward. An experimental investigation of TCC is conducted with pressed pairs of TC4/30CrMnSi contacts in the range 40~140MPa. The results show that TCC over this condition increases with load, and is greater in the process of unloading than that of loading under the same condition.
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Fernández, Ana María, José F. Marco, Paula Nieto, Fco Javier León, Luz María Robredo, María Ángeles Clavero, Ana Isabel Cardona, Sergio Fernández, Daniel Svensson, and Patrik Sellin. "Characterization of Bentonites from the In Situ ABM5 Heater Experiment at Äspö Hard Rock Laboratory, Sweden." Minerals 12, no. 4 (April 12, 2022): 471. http://dx.doi.org/10.3390/min12040471.
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The Alternative Buffer Material ABM5 experiment is an in situ medium-scale experiment performed at Äspö Hard Rock Laboratory (HRL) conducted by SKB in Sweden with the aim of analysing the long-term stability of bentonites used as an engineering barrier for a high-level radioactive waste repository (HLWR). In this work, four different ring-shaped Ca- and Na-bentonite blocks, which were piled around a carbon steel cylindrical heater, subjected to a maximum temperature of 250 °C and hydrated with saline Na-Ca-Cl Äspö groundwater (0.91 ionic strength), were characterized after dismantling. This work allowed us to identify the main geochemical processes involved, as well as the modifications in the physico-chemical properties and pore water composition after 4.4 years of treatment. No significant modifications in mineralogy were observed in samples close to the heater contact, except an increase in Fe content due to C-steel corrosion, carbonate dissolution/precipitation (mainly calcite and siderite) and Mg increase. No magnetite and a low amount of Fe(II) inside the clay mineral structure were detected. No modifications were observed in the smectite structure, except a slight increase in total and tetrahedral charge. A decrease in external surface area and cation exchange capacity (CEC) was found in all samples, with lower values being detected at the heater contact. As a consequence of the diffusion of the infiltrating groundwater, a modification of the composition at clay mineral exchange sites occurred. Ca-bentonites increased their Na content at exchange sites, whereas Na-bentonite increased their Ca content. Exchangeable Mg content decreased in all bentonites, except in MX-80 located at the bottom part of the package. A salinity gradient is observed through the bentonite blocks from the granite to the heater contact due to anions are controlled by diffusion and anion exclusion. The pore water chemistry of bentonites evolved as a function of the diffusion transport of the groundwater, the chemical equilibrium of cations at exchange sites and mineral dissolution/precipitation processes. These reactions are in turn dependent on temperature and water vapor fluxes.
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Bao-Min, Liu, and Mui Y. C. "Multi-Physics Simulation of a Microprocessor Package Under Water Cooling." Journal of Electronic Packaging 126, no. 3 (September 1, 2004): 384–89. http://dx.doi.org/10.1115/1.1774197.
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Simulation tools today are well developed and make it possible to study more than one physical phenomena in the engineering processes. In this paper, a multi-physics simulation was performed to investigate the thermal, hydraulic and stress behavior of a flip-chip microprocessor package and a water-cooling thermal system. The distribution of the temperature, velocity, pressures, and stress inside the integrated circuit (IC) package and the water jacket was predicted and analyzed. The thermal resistance, Rjw, was defined and calculated to evaluate the overall thermal performance. The difference between the numerically predicted Rjw and the experimental result is within 10%. Thermal and hydraulic parametric studies were performed on the parameters such as the water flow rate, the die size, the channel height, and the base thickness of the water jacket. The impact of heater was also investigated to optimize the heater efficiency under different thermal contact between the IC package and the thermal head. Stress simulation was performed on the heater plate and the IC package subject to the temperature profile. The thermal stress and deformation were found to be at safe level under the given conditions. The results show that the use of multi-physics simulation and analysis can provide a deeper insight of complex processes, as well as to investigate the key parameters for system optimization. The numerical approach can reduce the risk and uncertainties at design stage as well as improve the system performance at the production stage.
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Hermanuadi, D., A. Brilliantina, and EKN Sari. "Design of Flash Dryer Cum-UV for Improving the Quality of Drying Cassava Chip." IOP Conference Series: Earth and Environmental Science 980, no. 1 (February 1, 2022): 012003. http://dx.doi.org/10.1088/1755-1315/980/1/012003.
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Abstract Drying is a scientific operation, which includes the transient transfer of heat and mass at some rate of process. The purpose of this study was to design and create a flash system dryer, which is equipped with UV. The selection of flash system dryers is based on conditions where some materials to be dried are sensitive to hot air contact due to prolonged drying. As a heat source, this dryer uses a heater to heat the air. In order to spread the heat evenly in the dryer room, the blower is installed on the heater. The intake of air blower is 60 m/s, while the air temperature on the air heater is conditioned at 50 and 60ºC. In order to collect data of air temperature, a thermocouple is placed on heat channel pipe and dryer room. The performance test of the dryer by using cassava chips, showed that the lowest cassava chip water content was 7,2% at 50ºC treatment temperature, and the highest water content by 18.5% at treatment temperature of 60ºC.
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Ramadhani, Ari. "Water Temperature Control Using PID Control System Based on LabVIEW." Telekontran : Jurnal Ilmiah Telekomunikasi, Kendali dan Elektronika Terapan 4, no. 2 (July 23, 2016): 35–46. http://dx.doi.org/10.34010/telekontran.v4i2.1888.
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Abstract - Automatic system have grown widespread across all sector so do water heater. Traditionally, heating water is done by utilizing fire as heat source. As the growing of technology, the heating process could be done by manipulating electrical energy by convert it to heat. Electrical energy is flown to a metal rod that contact directly with the water which increase the water temperature. On some case, appropiate water temperature is needed. Altough, a thermometer is needed to read the actual temperature as a feedback value for the system and a system that can control the electricity current flow through the heater that the heat produced is linear to the current flow. With implementing microcontroller as a process node for generating PWM signal, this problem can be solved. Also, Labview is needed as an interface for monitoring and bursting an output which have been processed by Proportional, Integral, and Devivative (PID) controller to producing accurate and stable heat. Based on the results of testing, the system is able to provide a rapid response to any changes that occur, both changes in set-point and changes in water temperature (actual value). Another test is done by comparing the temperature value detected by the temperature sensor in this device with an external digital thermometer placed in the same place, and from some of the tests the temperature value detected by the temperature sensor in this device has a difference of ± 0.19 ℃ with a digital thermometer. Keyword : Water Heater, Thermometer, Microcontroller, LabView, PID.
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Kolhare, N. R., and P. R. Thorat. "AN APPROACH OF FLOW MEASUREMENT IN SOLAR WATER HEATER USING TURBINE FLOW METER." INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 4, no. 1 (February 1, 2013): 1–4. http://dx.doi.org/10.24297/ijct.v4i1a.3024.
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boost its use in domestic applications. A Techno-economical system is designed using microcontroller based turbine flow meter to measure flow of water in solar water heater. There is no need of bulky remote electronics system. Here a turbine is inserted in the pipeline which rotates around its axis the speed of this rotation is directly proportional to the rate of flown. To measure the flow electronically through non-contact method  one arm of the turbine can be made of a magnet and a Hall Effect device attached on the outer side of the pipe. The Hall Effect switch would pick up the passage of the magnetic arm and generates a pulse. By counting the number of pulses per second or minute depending on the speed of the turbine and the desired resolution (i.e. multiplication factor) the flow can be calculated.
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Liaw, S. P., and V. K. Dhir. "Void Fraction Measurements During Saturated Pool Boiling of Water on Partially Wetted Vertical Surfaces." Journal of Heat Transfer 111, no. 3 (August 1, 1989): 731–38. http://dx.doi.org/10.1115/1.3250744.
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Void fraction profiles adjacent to a vertical wall 6.3 cm wide and 10.3 cm high were measured during nucleate boiling. The experiments were conducted in saturated water at 1 atm pressure. In the experiments, the wettability of the surface was varied by controlling the degree of oxidation of the surface. Static contact angle was used as an indicator of the surface wettability. The void fraction was measured with a gamma densitometer. The experimental results show that the maximum void fraction occurs about 1–1.5 mm away from the heater surface. The wall void fraction, the maximum void fraction, and the thickness of the void layer increase with wall heat flux. It is found that for a given heat flux, the wall void fraction increases as the surface becomes less wettable, whereas the maximum heat flux decreases with increase in contact angle.
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Markus, Bongert, Wüst Jan, Strauch Justus, and Buchwald Dirk. "Proof of Concept for Ozone-Based Disinfection of Heater Cooler Units." Current Directions in Biomedical Engineering 6, no. 3 (September 1, 2020): 292–94. http://dx.doi.org/10.1515/cdbme-2020-3074.
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AbstractHeater Cooler Units (HCUs) are frequently used not only during heart surgery but also in ECMO therapy to regulate the blood temperature of patients. It is known from cardiac surgery that the water circuits of HCUs can be bacterially contaminated and under adverse conditions can lead to a nosocomial infection of the patient. The addition of chemical disinfectants to the water of HCUs is problematic. In addition, it is an increasingly significant cost factor due to the required material and personnel input. The aim of this research project is both the development of an automated device for disinfecting water in HCUs and proof of its effectiveness. The device is based on ozone, a substance with known antimicrobial properties. To prevent ozone from coming into contact with the HCU components, the water is irradiated with UV light (254nm). Two bypasses and ozone sensors guarantee a complete elimination of residual ozone. The effectiveness of the device was tested by series of experiments with the surrogate germ, Pseudomonas aeruginosa. The device allows a wide range of ozone concentrations and exposure times to be selected. In previous test series, it has been shown both that a reduction of the bacterial count to drinking water quality can be achieved with a treatment time of only one hour, and that self-cleaning can be carried out effectively before clinical use, and in standby mode. Attention must be paid to the water quality in HCUs as a potential source of infection, regardless of where they are used. The "proof of concept" showed an excellent disinfection effect with simultaneous elimination of excess ozone to drinking water levels. The number of indicator bacteria in the water tank of the dummy HCU was reduced by approx. 98% after only 30 minutes.
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Jones, J. B., A. J. F. Webster, and C. M. Wathes. "Trade-off between ammonia exposure and thermal comfort in pigs and the influence of social contact." Animal Science 68, no. 3 (April 1999): 387–98. http://dx.doi.org/10.1017/s1357729800050384.
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AbstractThe trade-off made by pigs between exposure to a concentration of ammonia gas recorded in commercial piggeries and thermal comfort was observed in two chronic choice tests. In the first experiment, eight pigs which were paired and eight pigs which were held as singles, were forced to choose between compartments of a preference chamber that were polluted with an ammonia gas concentration of 40 p.p.m. and heated with a 750 W radiant heater or compartments that were unpolluted and unheated, for 8 days. The location of the choice options was switched after 4 days to eliminate positional bias. Air temperature ranged from 0·5 °C to 15·0 °C. In the second experiment, eight pigs held as pairs, were free to choose between compartments that were polluted with an ammonia gas concentration of 40 p.p.m. and heated with a 750 W radiant heater, polluted and unheated, unpolluted and heated and unpolluted and unheated, for 14 days. The location of the choice options was switched after 7 days to eliminate positional bias. Air temperature ranged from 4·0 °C to 24·0 °C. All compartments contained food and water ad libitum; wood shavings were used as bedding material. In both experiments, the location of all pigs was scan sampled every 15 min and their behaviour at this time was recorded instantaneously. Location and behaviour were compared against air temperature. In the first, forced choice experiment, the pigs preferred the heated-polluted compartments when air temperature was less than the estimated lower critical temperature (LCT) (P< 0·001). As air temperature approached the estimated LCT, the pigs occupied the unheated-unpolluted compartments more often. Overall each visit made to the heated-polluted compartments lasted significantly longer at 265 min (paired), 208 min (single) than visits to the unheated-unpolluted compartments at 29 min (paired), 31 min (single) (P< 0·001). Although they could have huddled to conserve heat, the paired pigs spent less time, overall, in the unheated-unpolluted compartments (P< 0·001). When air temperatures were lower than the estimated LCT, the pigs huddled together but as air temperature increased, the pigs spent more time resting apart (P< 0·001) in the heated-polluted compartments. It is suggested that the paired pigs were motivated to remain in the heated-polluted compartments for companionship rather than thermal comfort. In the second, free choice experiment, the pigs preferred to remain in the unpolluted compartments, adjusting their occupancy of the heated and unheated compartments as ambient air temperature decreased or increased above the estimated LCT (P< 0·001). The pigs made fewer visits to the polluted compartments and each visit was shorter, at 44 min (P< 0·001). Visits to the unpolluted compartments lasted for 291 min. It is suggested that the delayed aversion shown to ammonia in both experiments was due to a progressive sense of malaise. However, both experiments indicated that this delayed ammonia aversion was weaker than preference for thermal comfort.
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Kandlikar, Satish G. "A Theoretical Model to Predict Pool Boiling CHF Incorporating Effects of Contact Angle and Orientation." Journal of Heat Transfer 123, no. 6 (April 23, 2001): 1071–79. http://dx.doi.org/10.1115/1.1409265.
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A theoretical model is developed to describe the hydrodynamic behavior of the vapor-liquid interface of a bubble at the heater surface leading to the initiation of critical heat flux (CHF) condition. The momentum flux resulting from evaporation at the bubble base is identified to be an important parameter. A model based on theoretical considerations is developed for upward-facing surfaces with orientations of 0 deg (horizontal) to 90 deg (vertical). It includes the surface-liquid interaction effects through the dynamic receding contact angle. The CHF in pool boiling for water, refrigerants and cryogenic liquids is correctly predicted by the model, and the parametric trends of CHF with dynamic receding contact angle and subcooling are also well represented.
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Kaufhold, S., R. Dohrmann, K. Ufer, and F. Kober. "Interactions of bentonite with metal and concrete from the FEBEX experiment: mineralogical and geochemical investigations of selected sampling sites." Clay Minerals 53, no. 4 (December 2018): 745–63. http://dx.doi.org/10.1180/clm.2018.54.
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ABSTRACTThe FEBEX experiment, a full-scale, high-level radioactive waste repository test, ran for ~18 years and hence is the longest-running disposal test to date. The test consisted of a heater emplaced in an envelope of compacted bentonite at the Grimsel test site, Switzerland. The water content of the bentonite was somewhat lower near the heater and increased towards the granite. This phenomenon probably led to gradients in the exchangeable cation population at various locations within the bentonite buffer. The cement (shotcrete) bentonite interface of one block was characterized by a thin (0.1–1.0 mm) reaction zone in which bentonite constituents, carbonates and sulfates occurred. Cation exchange and a slight decrease of the cation exchange capacity were observed near the heater. Oxic corrosion was observed predominantly at the bentonite/steel liner interfaces, pointing towards a role of air entrapped between the liner and heater during emplacement. At the liner surface, intimate intergrowth of bentonite constituents, metal and corrosion products was observed. At the face of the heater, the bentonite blocks were in direct contact with the heater surface without any signs of metal corrosion. Instead, a significant increase in the Mg content was recorded, which is in agreement with previous large-scale disposal tests. The FEBEX experiment proved that the Mg increase and corrosion were independent processes. The increase in Mg may be explained by the formation of trioctahedral domains or the precipitation of neoformed silicates. For the first time, however, brucite was identified as an additional phase that formed at the metal/bentonite interface, pointing towards a special role for Mg mobility in the bentonite barrier.
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Surtaev, Anton, Vladimir Serdyukov, and Alexey Safonov. "Characteristics of Boiling Heat Transfer on Hydrophobic Surface." EPJ Web of Conferences 196 (2019): 00054. http://dx.doi.org/10.1051/epjconf/201919600054.
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The paper presents the results of an experimental study of the effect of hydrophobic fluoropolymer coating on the multiscale characteristics of heat transfer at water boiling. New experimental data on dynamics of vapor bubble growth and detachment, evolution of contact line, nucleation site density, heat transfer coefficient were obtained using high-speed imaging techniques, including infrared thermography and video recording from the bottom side of transparent ITO heater. It was shown, that the using of hydrophobic fluoropolymer coating leads to heat transfer enhancement, to decrease of the superheat temperature at the onset of boiling, to increase of the active nucleation site density and to significant change in the dynamics of growth and departure of vapor bubbles and the evolution of the triple contact line.
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Watcharodom, Niran, Withaya Puangsombut, Joseph Khedari, Narong Vatcharasatien, and Jongjit Hirunlabh. "Experimental Investigation of Thermoelectric Power Generation Using Radiative Heat Exchange." Advanced Materials Research 1025-1026 (September 2014): 1125–33. http://dx.doi.org/10.4028/www.scientific.net/amr.1025-1026.1125.
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This paper reports experimental investigation of a new concept of waste heat recovery for Thermoelectric Power Generation using Radiative heat exchange principle (TERX). To this end a small scale experimental setup was considered; it was composed of a heated plate, an absorber plate, thermoelectric modules and water cooled heat sink. The dimensions of absorber and heated plates were 0.2 m width and 0.3 m length. The air gap space between the two plates could be adjusted. Ten thermoelectric modules were connected in series parallel (5x2). Tests were made for different air gap spaces and fixed water flow rate (2L/min). A constant electric current (200W) was supplied to the heater of hot plate. Data collected included temperature at various positions and the electrical power generated. Experimental investigation confirmed that using radiative heat exchange principle could be considered for TE waste heat power generation. Increasing air gap decreased the electrical power generated as less radiative heat is absorbed by the thermoelectric modules. Under test conditions, the maximum measured electrical power is 0.3132 W at 0.5 cm of air gap, the corresponding temperature difference between the hot and cool sides of thermoelectric modules was about 35oC. Due to its simplicity of installation as no there is no need for direct contact between the thermoelectric generation set and the source of heat, the proposed concept offers a new alternative for waste heat recovery.
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KWARK, SANG M., MIGUEL AMAYA, and SEUNG M. YOU. "EXPERIMENTAL POOL BOILING HEAT TRANSFER STUDY OF THE NANOPOROUS COATING IN VARIOUS FLUIDS." International Journal of Air-Conditioning and Refrigeration 20, no. 01 (March 2012): 1150001. http://dx.doi.org/10.1142/s2010132511500015.
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An experimental pool boiling study was conducted using plain and nanoporous coated heater surfaces immersed in various working fluids: water, ethanol and HFE-7100. Pool boiling tests were performed on flat 1 cm × 1 cm heaters. Unlike in water, the critical heat flux (CHF) enhancement of the nanoporous coating seems to be less or marginal in ethanol and HFE-7100 at 1 atm. The reduced effect of the nanoporous coating in ethanol and HFE-7100 is believed to be due to the highly wetting nature of these fluids since no obvious difference in wettability is observed between nanoporous coated and uncoated surfaces through apparent contact angle measurement. Moreover, pressure effects were also investigated for the fluids mentioned above. For the nanoporous coated surface, CHF enhancement of the nanoporous coating appeared to be dependent on the test pressure, showing greater CHF enhancement at lower pressure. It is believed that this pressure dependent CHF enhancement behavior could be closely related to the bubble departure diameter. As pressure lowers, the departure bubble size increases and this allows the nanoporous coating to become more influential, even for the highly wetting fluids, in delaying local dry-out, which in turn results in increasing CHF enhancement.
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Pottie, D. L. F., L. H. C. Dias, R. P. Mendes, L. V. S. Martins, and R. A. M. Ferreira. "EXPERIMENTAL STUDY OF A DOMESTIC SOLAR HEATER WITH IRON ORE AS THE ABSORBER." Revista de Engenharia Térmica 19, no. 1 (September 9, 2020): 13. http://dx.doi.org/10.5380/reterm.v19i1.76425.
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In Brazil's households, the use of electricity to heat water prevails, but its replacement by solar collectors can be justified due to the country's high level of solar radiation, average temperature and number of sunny days. A drawback preventing the broad spread of this technology its elevated inicial cost that, in spite of the short return on investment time, hinders its insertions on the population lower classes. Thereby, this study's goal is to search a cheaper alternative to one of the collector's most expensive component, by proposing the replacement of the aluminium sheets, used as absorber, by iron ore. This material was chosen due to its abundance in Minas Gerais, low cost and for being dark colored, ensuring high levels of absortance (0,4 < λ< 0,7 µm). A finely grained hematitic () ore was used to achieve an uniform compaction throughout its area, reducing this way, the thermal contact resistance between the absorber and the copper tubes. The collector was built and tested in similar conditions it would have faced during its lifespan, and the result shows that the maximum thermal efficiency was 58%.
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Ma, Linxu, Lina Wang, Chengying Li, Jian Guo, Pranav Shrotriya, Cui Deng, and Jingnan Zhao. "Hybrid Nanosecond Laser Processing and Heat Treatment for Rapid Preparation of Super-Hydrophobic Copper Surface." Metals 9, no. 6 (June 9, 2019): 668. http://dx.doi.org/10.3390/met9060668.
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The super-hydrophobic copper surface was obtained by using a nanosecond pulsed laser. Different micro- and nano-structures were fabricated by changing the laser scanning interval and scanning speed, before heating in an electric heater at 150 °C for two hours to explore the effect of laser parameters and heat treatment on the wettability of the copper surface. It was found that the laser-treated copper surface is super-hydrophilic, and then, after the heat treatment, the surface switches to hydrophobic or even super-hydrophobic. The best super-hydrophobic surface’s apparent contact angle (APCA) was 155.6°, and the water sliding angle (WSA) was 4°. Super-hydrophobic copper is corrosion-resistant, self-cleaning, and dust-proof, and can be widely used in various mechanical devices.
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Savu, Sorin Vasile, I. Danut Savu, and Ion Ciupitu. "Thermal Analysis to Evaluate Ageing Process in Heated Tool and Electrofusion Welding of Polymer Pipes." Advanced Materials Research 837 (November 2013): 190–95. http://dx.doi.org/10.4028/www.scientific.net/amr.837.190.
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Heated tool and electrofusion welding are the most used joining processes of higher than 2 mm thick polymer pipes. The two welding processes have different heating-cooling cycles and they produce different influences on the properties of the polymers. Exploitation of polymer pipes for water and gas distribution revealed ageing behaviour of the material in the welding area. The modification of the behaviour depends on the base material, on the applied welding process and on the used parameters. Thermal analysis can be used as tool to reveal and to evaluate the modification of the physical and mechanical properties. Such knowledge is important when prediction of the in use life is necessary to be predicted. Experimental programme was applied to HDPE 100 and HDPE 80, both welded using heated tool and electrofusion processes and different sets of parameters (factorial experiment principles were used to establish the welding parameters). Plasticity characteristics of the welds material, as elongation and relaxation modulus, were determined by using thermal analysis. Burst stress test, applied to the pipe, was considered. It has been observed important rate of the heating process of the surface in contact with the heater. The DSC analysis revealed a decreasing of the elongation with about 12% and decreasing of the relaxation modulus with amount up to 14%, for the material located at the interface between pipe and the heater. At 0.5 mm from the interface it was revealed an intensity of the modification up to half of the values recorded for the interface. That was explained on the poor thermal conductivity specific to the both materials. By using DSC thermal analysis it has been revealed that the polyethylene has high rate crystallization during welding cycle, after the heating to the viscous state. Such crystallization, together with potential non-uniformity of the heating provides modifications in the geometrical characteristics of the weld. For high energy input, the material experience large quantity of fluid material with important plastic distortion. That means high possibility to reject material during pressing step of the welding cycle. 10% increasing of the temperature, for the same heating pressure, involves 5-8% increasing of the dimensions of the fluid ring in the interface. About 10% difference between the relaxation modulus of the heated and non-heated HDPE and that means local ageing transformation of the HDPE. The material becomes more fragile than before the welding process.
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Kler, A. M., E. L. Stepanova, and P. V. Zharkov. "Determination of the Design Characteristics of Heat Exchange Equipment for Heating Network Water of a Cogeneration Gas Turbine Unit with a Change in the Heat Load of Consumers in Regions with Different Climatic Conditions." Journal of Physics: Conference Series 2096, no. 1 (November 1, 2021): 012015. http://dx.doi.org/10.1088/1742-6596/2096/1/012015.
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Abstract Optimization studies of the dependence of fuel consumption on changes in the heat load of consumers in regions with different climatic conditions and taking into account the determination of the design characteristics of the equipment for heating network water of a cogeneration GTU were carried out. The GTU has two fuel combustion chambers, a waste-heat boiler and a contact heat exchanger for heating of feeding network water. Schematic-parametric optimization studies were carried out on the design mathematical model of the GTU. The analysis of the data of the circuit-parametric optimization made it possible to conclude that for the operating modes of the gas turbine plant with a higher thermal load, it is advantageous to slightly increase the heating surface area of the heater of feeding network water, the cost of materials for the manufacture of which is lower than for the waste heat boiler. This technical solution provided a relatively low increase in specific capital investments with full provision of consumers with electric and thermal energy. The data obtained in this work can be used to select the optimal technical solutions that ensure competitiveness in the operation of a cogeneration gas turbine unit in regions with different climatic characteristics.
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Zhang, Juntao, and Raj M. Manglik. "Effect of Ethoxylation and Molecular Weight of Cationic Surfactants on Nucleate Boiling in Aqueous Solutions." Journal of Heat Transfer 126, no. 1 (February 1, 2004): 34–42. http://dx.doi.org/10.1115/1.1643755.
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Saturated, nucleate pool boiling on a horizontal, cylindrical heater and the associated bubble dynamics in aqueous solutions of cationic surfactants of different molecular weight and ethoxylation or ethylene oxide (EO) content, are experimentally investigated. Boiling curves qw″∝ΔTsat for different concentrations and photographic records of the salient features of the ebullient behavior are presented, along with a characterization of interfacial properties (surface tension and contact angle). The surfactant additive significantly alters the nucleate boiling in water and enhances the heat transfer. The enhancement increases with concentration, with an optimum obtained in solutions at or near the critical micelle concentration (c.m.c.) of the surfactant. The photographic and visual observations indicate a markedly different boiling behavior than that of water, as well as between pre- and post-c.m.c. solutions. A lower molecular weight surfactant tends to reduce surface tension faster, and show better enhancement performance than its higher molecular weight counterpart. With EO groups in its molecular chain the surfactant solution becomes more hydrophilic, and the higher wettability tends to suppress nucleation, thereby weakening the boiling process. Also, enhancement in pre-micellar solutions is shown to depend on the dynamic surface tension, and the number of EO groups in and molecular weight of the surfactant.
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Stepanova, E. L., and P. V. Zharkov. "A study of the dependence between fuel consumption of a heat gas turbine and variation of heat loading of regional consumers having various climatic conditions taking into account determination of structural characteristics of heat exchanging equipment for grid water heating." Proceedings of Irkutsk State Technical University 25, no. 4 (September 1, 2021): 478–87. http://dx.doi.org/10.21285/1814-3520-2021-4-478-487.
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The aim was to optimize the dependence between fuel consumption and heat loading of regional consumers varied due to climatic conditions, taking into account the determination of structural characteristics of heat exchanging equipment for grid water heating in a heat gas turbine. A heat gas turbine comprising two fuel combustion chambers, a waste-heat boiler and a contact heat exchanger to heat makeup grid water was investigated. Scheme and parametric optimization studies were carried out using a mathematic model of a gas turbine created using a software and hardware system developed at the Department of Heat Power Systems of the Melentiev Energy Systems Institute, Siberian Branch of the Russian Academy of Sciences. Th turbine operating conditions differing in heat loads in four suggested operating regions were studied. It was found that an increase in fuel consumption in the second combustion chamber was 29%– 84% compared to that in the first combustion chamber. This rise was recorded when the turbine heat loading was increasing in the considered regions. Data analysis of the scheme and parametric optimization studies showed that, for operating conditions with a higher heat loading, it seems reasonable to ensure the maximum possible heating of makeup grid water as the loading rises. It is also recommended to slightly increase the heat surface area of the makeup grid water heater whose structural materials are less expensive than in a waste-heat boiler. It was shown that the suggested technical solution slightly increases specific capital investments while fully providing electrical and heat power to consumers. The obtained results can be used to select optimal technical solutions ensuring competitiveness in the operation of a heat gas turbine in regions with various climatic characteristics.
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Namazu, Takahiro, and Shozo Inoue. "Al/Ni Self-Propagating Exothermic Film for MEMS Application." Materials Science Forum 638-642 (January 2010): 2142–47. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.2142.
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This paper describes evaluation of the strength in Ag-Sn-jointed Si specimens heated by Al/Ni film’s exothermic reaction. The reaction generates heat enough to melt Ag-Sn film for soldering. To measure the strength, four-point micro-bending test technique has been developed. The rectangular-solid Si specimens having a Ag-Sn/AlNi/Ag-Sn section were prepared by dicing the bonded Si-wafer under various pressure loads. A higher pressure yielded a better contact condition between Al/Ni and Ag-Sn so that heat-conduction improved; consequently Ag-Sn was melted sufficiently. Al/Ni reactive film has a potential as a micro-heater in soldering for MEMS.
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Dohrmann, R., S. Olsson, S. Kaufhold, and P. Sellin. "Mineralogical investigations of the first package of the alternative buffer material test – II. Exchangeable cation population rearrangement." Clay Minerals 48, no. 2 (May 2013): 215–33. http://dx.doi.org/10.1180/claymin.2013.048.2.05.
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AbstractBentonites are candidate materials for the encapsulation of radioactive waste. In the ‘Alternative Buffer Material test’ (ABM), compacted ring-shaped blocks of eleven different buffer materials (mainly bentonites) were packed vertically on top of each other with an iron tube as heater in the centre. These buffer materials started with various exchangeable cation populations (ECpopulation). The first ‘ABM package’ was terminated 28 months after installation and the bentonites had been exposed to the maximum temperature (130°C) for about one year. The aim of the present study is first: to describe modification of the cation exchange population, and second to understand the influence of the groundwater on cation exchange at different scales. No significant horizontal variation of any exchangeable cation (EC) was detected between 1 and 7 cm distance from contact with the iron tube. Large total differences of the ECpopulations, however, were observed for the individual blocks after the field experiment (n = 21 blocks) with respect to the composition of the reference materials. The average cation exchange capacity (CEC) values of the analysed bentonites (n = 9 blocks) decreased by 5.5 meq/100 (1.1 – 8.8 meq/100 g) after the experiment. Exchangeable Na+ and Mg2+ decreased on average, whereas Ca2+ increased. This trend was pronounced in the top region of the parcel (upper seven blocks). Although most changes occurred on the large scale of the whole test parcel, small but important changes were also recorded in the vertical direction on the centimetre scale. The observed differences cannot be explained assuming simply that a bentonite reacts only with neighbouring blocks, which would mean that the system was more or less closed. The differences are much larger and the only conclusion from this observation is that the whole package seems to be influenced by the groundwater which was added from a water tank at the experiment site, enabling at least partial equilibration between the different blocks.
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Moore, R. G., C. J. Laureshen, M. G. Ursenbach, S. A. Mehta, and J. D. M. Belgrave. "Combustion/Oxidation Behavior of Athabasca Oil Sands Bitumen." SPE Reservoir Evaluation & Engineering 2, no. 06 (December 1, 1999): 565–71. http://dx.doi.org/10.2118/59483-pa.
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Summary Oils that are potential candidates for in situ combustion recovery processes are often screened by means of their oxidation characteristics: in particular, the kinetics of the ignition process and the transition from low-temperature to high-temperature oxidation through what is known as the "negative temperature gradient region." These characteristics are readily studied in ramped-temperature oxidation tests, which involve the controlled heating of recombined, oil-saturated cores in a one-dimensional plug flow reactor under a flowing stream of air (or oxygen-containing gas). The purpose of these tests is to study the global oxidation behavior and reaction kinetics under controlled conditions, with the end purpose of providing realistic data for incorporation into a numerical simulator which can be used to predict field performance. A ramped-temperature oxidation apparatus was used to conduct a detailed, two-year parametric study of the oxidation characteristics of Athabasca Oil Sands bitumen. The text matrix involved various levels of pressure, gas injection rate, oxygen content of the injected gas, and maximum ramptemperature. This paper details the principal findings for the 45-test study;especially the need to maintain high reaction temperatures >380°C) in order to mobilize and produce heavy oils under conditions of dry in situ combustion. Design considerations and operational guidelines for successful field projectsarising from the results of this study are also discussed. Introduction In order to successfully exploit the vast potential of processes based on the injection of air or an oxygen-containing gas for the recovery of conventional and heavy oils, it is necessary to understand the nature of the oxidation reactions which are involved. The traditional definition of in situ combustion, which is based on the high-temperature combustion of a coke-like fuel, does not explain the combustion behavior which is observed in many field projects or even in laboratory combustion tube experiments. For this reason, a number of experiments have been developed which concentrate on the global oxidation kinetics. These studies normally involve exposing the crude oil to a programmed rate of heating while in contact with the oxidizing gas. The oxidation kinetics are then observed using effluent gas analysis techniques,1–7 and differential thermal techniques such as the differential thermal analysis (DTA) work of Vossoughi et al.,8 the pressurized differential scanning calorimetry (PDSC) studies of Phillips et al.9 and Belkharchouche and Hughes,10 and the accelerating rate calorimetry (ARC) technique of Yannimaras et al.11 Previous investigations of the oxidation reactions which occur during in situ combustion processes have shown the existence of at least two temperature ranges over which the oxygen uptake rates are significant. 2,4-7While Kisler and Shallcross have reported that the light (40.2°API) Australian oil which they studied exhibited at least three temperature ranges over which localized maxima in the oxygen uptake rate were observed, the majority of heavy oils for which oxidation data have been reported show only two distinct local maxima in the oxidation rates. For convenience, the two temperature ranges where elevated oxygen uptake or energy generation rates are observed are denoted as the low-temperature oxidation (LTO) and high-temperature combustion(HTC) regions. For heavy oils, the range of temperatures associated with the low-temperature oxidation region is roughly from 150 to 300°C, while the high-temperature combustion region generally corresponds to reaction temperatures in the range from 380 to 800°C. The transition temperature range which falls between the low-temperature oxidation and high-temperature combustion regions is characterized by reduced oxygen uptake and energy generation rates. The lower temperature portion of this transition range in which the oxygen uptake and energy generation rates decrease with increasing temperature is the "negative temperature gradient region" (NTGR). This behavior is illustrated in Fig. 1, which is the temperature history for a test involving a heater temperature of 350°C (near the upper end of the NTGR). This test, which was previously described by Moore et al.,12 shows that a distinct low-temperature reaction zone formed when the temperature was approximately 140°C and it propagated through the core for a short period of time as the heater continued its ramp towards the setpoint maximum temperature of 350°C At the end of the propagation period, the centerline temperatures remained very close to the heater temperature as the latter was increased over the temperature interval from 280 to 330°C It is apparent from the small temperature differences between all of the centerline locations and the heater that energy generation over this temperature interval was very low. A high-temperature reaction zone started to form when the temperature at the first thermocouple location attained 355°C. Fig. 2 provides the oxygen uptake history for the same test, and the data show that there were also two distinct periods of high oxygen uptake rates. The first period corresponds to the time that the lower-temperature reaction zone propagated through the core, and it is apparent that the prime mode of oxygen uptake is by reactions which do not result in the formation of carbon oxides. These reactions have been denoted as LTO reactions, although it should be noted that hydrogen conversion to water (which is normally classified as a combustion reaction) is included as a LTO reaction. Oxygen uptake rates associated with the second period correspond to the propagation of the high-temperature reaction zone. At these higher temperatures, oxygen consumption is primarily associated with the formation of carbon oxides. Oxygen uptake by LTO reactions is also significant, but this reflects the inclusion of hydrogen conversion to water as a LTO reaction. In essence, the oxidation reactions associated with the high-temperature propagating reaction zone are those which are normally designated as high-temperature combustion, in that the primary products are carbon oxides and water.
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Yamada, Yumi, and Minoru Takahashi. "ICONE15-10153 NUMERICAL ANALYSIS OF LEAD-BISMUTH-WATER DIRECT CONTACT BOILING HEAT TRANSFER." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2007.15 (2007): _ICONE1510. http://dx.doi.org/10.1299/jsmeicone.2007.15._icone1510_65.
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Komatsu, Wilson, Cláudio José de Oliveira Júnior, and Paulo Sérgio Valle Carvalho. "Direct Water Heater Power Control For Reduced Harmonics And Flicker Content With Optimized Half-cycle Power Control." Eletrônica de Potência 11, no. 3 (November 1, 2006): 175–80. http://dx.doi.org/10.18618/rep.2006.3.175180.
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Cai, R., W. K. Tan, Fern Lan Ng, and Chang Q. Sun. "Influence of Crystal Structure, Morphology and Sodium Ion on the Photocatalytic Reactivity of Spray Deposited Titanium Dioxide Film." Key Engineering Materials 447-448 (September 2010): 734–39. http://dx.doi.org/10.4028/www.scientific.net/kem.447-448.734.
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In this paper, three types of titanium dioxide structures (anatase, heated amorphous and amorphous) from peroxo titanium complex were deposited on glass and wafer substrates by spraying technique. Influences of crystal structure, morphology and sodium ion on UV induced hydrophilicity were studied. X-ray diffraction revealed that crystalline anatase coatings are extremely hydrophilic (<10°) under UV irradiation (indoor) while the amorphous coatings are still hydrophobic on both glass and wafer substrate with contact angles as high as 70º. When amorphous coating was heated at 450°C, its structure was converted into crystalline anatase, and hence its UV induced hydrophilicity behavior on wafer substrate became similar to that of anatase. However, this UV induced hydrophilicity was inhibited on heated glass (450°C), suggesting that sodium ions in the glass might be responsible for the differences between silicon wafer and glass. With increasing coating thickness, such inhibition effect was reduced, but the hydrophilicity still could not reach the level of anatase. After 6 months of outdoor exposure, water contact angle for amorphous, heated amorphous and anatase were 61°, 26.6° and 12.1°, respectively. Also, X-ray diffraction suggested that amorphous is not converted into anatase after long period of UV exposure, although coating morphologies are changed based on Scanning Electron Microscopic observation. It is concluded that the crystal structure, coating morphology and sodium ion concentration have key impact on the photocatalytic properties on glass substrate.
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Kaleda, K. G., and I. D. Cherkes. "ALTERATION OF GLAUCONITE MINERALS IN CONTACT WITH HEATED (100° C) WATER." International Geology Review 33, no. 2 (February 1991): 203–8. http://dx.doi.org/10.1080/00206819109465685.
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Van Hoorebeke, Justin, Alan Pang, and Nicole M. Kopari. "728 The Faces of Autologous Skin Cell Suspension as Epidermal Grafts." Journal of Burn Care & Research 41, Supplement_1 (March 2020): S195—S196. http://dx.doi.org/10.1093/jbcr/iraa024.312.
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Abstract Introduction Facial burns are frequently severe and are difficult to skin graft, which may lead to increased morbidity including chronic pain, scarring, and psychosocial stigma. The aim of this study was to describe outcomes of patients with facial burns who received autologous skin cell suspension as an epidermal graft. Methods A retrospective chart review of patients with facial burns admitted to an ABA verified Burn Center from January 2019 to August 2019 was performed. Each patient underwent tangential excision of superficial and deep partial-thickness burn wounds followed by autologous skin cell suspension applied as an epidermal autograft. The wounds were covered with a non-adherent dressing along with bismuth-impregnated, petroleum-based gauze. The dressings were secured in place with sutures to prevent disruption. On post-operative day 6 the dressings were removed with transition to an antimicrobial ointment applied to any remaining open wounds or a moisturizing lotion. Results Five patients, aged 41–89 years, were included. Total body surface ranged from 7–50%. Etiology of the burns included: flame from metal fabricating, assault followed by dousing the patient in gasoline and lighting on fire, flash flame from a water heater explosion, hot oil contact, and involvement in a house fire. 3 of the 5 patients had complete healing noted by post-operative day 6 with excellent results. Two patients required a second excision and application of autologous skin to small portions of the lateral face after healing the majority of the face. One patient developed mild microstomia requiring oral splinting. One of the two patients that required a second application developed ectropian to one of her eyes which was treated with temporary tarsorrhaphy. The second patient that required a second application, died during her hospitalization secondary to complications from her burns and underlying medical co-morbidities. Surviving patients reported satisfaction with the cosmetic outcomes. Conclusions Autologous skin cell suspension as an epidermal graft is a viable option for cosmetically important areas such as the face. This case series provides evidence for its validity when treating partial-thickness burns utilizing the above described protocol in conjunction with a multidisciplinary care team within a burn center. Applicability of Research to Practice By sharing our institutions experience with this relatively new technique we hope to share our positive outcomes as an alternative to stand excision and grafting to areas of significant cosmetic outcomes.
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Mizobe, Koshiro, Takahiro Matsueda, Gakuto Shinohara, Takuya Shibukawa, and Katsuyuki Kida. "Surface Observation of Induction-Heated 13Cr-2Ni-2Mo Stainless Steel after Interrupted Fatigue Testing under Rolling Contact Stress in Water." Solid State Phenomena 315 (March 2021): 72–76. http://dx.doi.org/10.4028/www.scientific.net/ssp.315.72.
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In order to investigate the wear behavior of induction-heated 13Cr-2Ni-2Mo stainless steel, we performed the rolling contact fatigue (RCF) tests in water. We interrupted the RCF test at each 1.0×105 cycles and measure the wear loss and observed the contact surface. After the RCF tests, we found the oxygen concentration area in the contact area.
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Cao, Yu, S. Alfonso Pérez-García, and Lars Nyborg. "Interface Reactions and Electrical Properties of Ta/4H-SiC Contacts." Materials Science Forum 556-557 (September 2007): 713–16. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.713.
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This study deals with the interfacial reactions and electrical properties of Ta/4H-SiC contacts. Tantalum thin films (~100 nm) were deposited onto SiC wafer at room temperature by argon ion beam sputtering. The samples were then heated in high vacuum at 650°C, 800°C or 950°C for 30 min. X-ray photoelectron spectroscopy (XPS), glancing angle X-ray diffraction (XRD), Auger electron spectroscopy (AES) and current-voltage (I-V) technique were used for characterising the samples. Ohmic contact is formed in the studied samples after annealing at or above 800°C even though considerable amount of metallic Ta still exists. The reaction zone possesses a layered structure of Ta2C/Ta2C+Ta5Si3/SiC. High enough temperature is needed to provide for sufficient interface change to tailor the contact properties.
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Ruiz, Orlando E., and William Z. Black. "Evaporation of Water Droplets Placed on a Heated Horizontal Surface." Journal of Heat Transfer 124, no. 5 (September 11, 2002): 854–63. http://dx.doi.org/10.1115/1.1494092.
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A numerical analysis of the evaporation process of small water droplets with diameters of 1 mm or less that are gently deposited on a hot isothermal solid surface has been performed. This study considers the internal fluid motion that occurs as a result of the thermocapillary convection in the droplet and it determines the effect of fluid motion on the heat transfer between the drop and the solid surface. This study is particularly relevant because the internal fluid motion has not been considered in previous numerical and analytical models presented in the literature. To assess the effects of internal fluid motion, the model results are compared to numerical results provided by a heat conduction model that neglects the fluid motion. The Navier-Stokes and Thermal Energy equations are solved using the Artificial Compressibility Method with Dual Time Stepping. Boundary-fitted grids are used to track the changes in the droplet surface shape during the evaporation process. The numerical simulations have demonstrated that the internal fluid motion provides vastly different temperature distributions in the drop compared to the results from the heat conduction model that neglects fluid motion. The evolution of the droplet geometry was simulated from an initial spherical-shaped cap until the contact angle was close to the receding contact angle.
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Kunts, K. A., D. Y. Kochkin, and O. A. Kabov. "Evaporation of a sessile droplet pinned by a groove on a heated substrate." Journal of Physics: Conference Series 2211, no. 1 (March 1, 2022): 012009. http://dx.doi.org/10.1088/1742-6596/2211/1/012009.
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Abstract The process of evaporation of sessile water droplets on a heated substrate was experimentally studied. A droplet evaporation is a fundamental phase change process which requires thorough consideration in various conditions. In this work we investigated the evaporation of water droplets on the smooth copper substrate with a circle groove made on its surface, which helped to keep the sessile droplet stable. Thus, the contact area of the evaporating droplet with the substrate remained constant, while the contact angle varied over a wide range. The experiment was conducted with a help of Krüss DSA100.
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Zhang, Fangfang, Xiangyu Li, Huajie Li, Jingdan Tang, Zhen Shen, Guopei Li, Tingxiang Jin, and Pei Yuan. "Impingement dynamics of droplets on mildly heated walls at initial and later stages." Physics of Fluids 34, no. 3 (March 2022): 037113. http://dx.doi.org/10.1063/5.0082244.
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The impingement dynamics of water droplets on a heated wall at initial and later stages are experimentally investigated. First, the effects of the wall temperature and the Weber number on the water droplet spreading characteristics are considered. A constant contact radius evaporation mode is observed during most of the evaporation. The wall temperature has little influence on the spreading characteristics at the initial stages. The Weber number greatly influences the spreading characteristics, such as the spreading dynamic behavior, maximum spreading time, spreading height, diameter, and contact angle, at the initial stages. At the later stages of spreading, the heating temperature has a relatively greater impact on the rate of linear change of the residual volume, whereas the impact of the Weber number on that is relatively small. Subsequently, the effect of evaporation on the impingement dynamics is investigated. The spreading characteristics of the water droplet are compared with those of an ionic liquid droplet (which does not experience evaporation), whereby the spreading factor increases and the volume remains unchanged with the increasing contact time in the absence of the evaporation effect.
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Dolotovskii, I. V., and N. V. Dolotovskaya. "Simulation of heat transfer in fire-tube and fire-tube-contact water heaters." Journal of Physics: Conference Series 1683 (December 2020): 042011. http://dx.doi.org/10.1088/1742-6596/1683/4/042011.
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Mikhlin, Yuri, Anton Karacharov, Sergey Vorobyev, Alexander Romanchenko, Maxim Likhatski, Svetlana Antsiferova, and Svetlana Markosyan. "Towards Understanding the Role of Surface Gas Nanostructures: Effect of Temperature Difference Pretreatment on Wetting and Flotation of Sulfide Minerals and Pb-Zn Ore." Nanomaterials 10, no. 7 (July 12, 2020): 1362. http://dx.doi.org/10.3390/nano10071362.
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Surface nanobubbles at hydrophobic interfaces now attract much attention in various fields but their role in wetting-related phenomena is still unclear. Herein, we report the effect of a preliminary contact of “hot” solids with cold water previously proposed for generation of surface nanobubbles, on wettability of compact materials and flotation of particulate galena (PbS), sphalerite (ZnS), and Pb-Zn sulfide ore. Atomic force microscopy was applied to visualize the nanobubbles at galena crystals heated in air and contacted with cold water; X-ray photoelectron spectroscopy was used to characterize the surface composition of minerals. Contact angles measured with the sessile drop of cold water were found to increase when enhancing the support temperature from 0 to 80 °C for sphalerite and silica, and to pass a maximum at 40–60 °C for galena and pyrite (FeS2) probably due to oxidation of sulfides. The temperature pretreatment depressed the recovery of sulfides in collectorless schemes and improved the potassium butyl xanthate-assisted flotation both for single minerals and Gorevskoye Pb-Zn ore. The results suggest that the surface nanobubbles prepared using the temperature difference promote flotation if minerals are rather hydrophobic and insignificantly oxidized, so the addition of collector and activator (for sphalerite) is necessary.
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Volkov, R. S., G. V. Kuznetsov, and P. A. Strizhak. "Movement and evaporation of water droplets under conditions typical for heat-exchange chambers of contact water heaters." Thermal Engineering 63, no. 9 (August 20, 2016): 666–73. http://dx.doi.org/10.1134/s004060151609007x.
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Shibayama, Shunsuke, Yutaka Abe, and Akiko Kaneko. "ICONE19-43284 HEAT AND MOMENTUM TRANSFER MECHANISMS UNDER THE DIRECT-CONTACT-CONDENSATION BETWEEN SUPERSONIC STEAM FLOW AND WATER JET." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2011.19 (2011): _ICONE1943. http://dx.doi.org/10.1299/jsmeicone.2011.19._icone1943_121.
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Gomonsirisuk, Khemmakorn, Kotchakorn Yotyiamkrae, Malee Prajuabsuk, Saisamorn Lumlong, Pharit Kamsri, Pornpan Pungpo, and Parjaree Thavorniti. "Synthesis of Zeolite from Water Treatment Sludge and its Application to the Removal of Brilliant Green." Key Engineering Materials 766 (April 2018): 111–16. http://dx.doi.org/10.4028/www.scientific.net/kem.766.111.
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In this work, water treatment sludge from the water treatment plant was used to synthesize zeolite material. In the synthesis, the washed sludge was mixed with sodium hydroxide and then heated at 600ºC for 6 h. After agitation, the aged material was heated in a water bath at 80ºC for different period of aging times. Based on XRD and SEM analyses, Faujasite zeolite was obtained. Then, the feasibility of employing the obtained zeolite as adsorbent for Brilliant Green (BG) removal was investigated. The effect of adsorbent dosage and contact time were examined. Adsorption kinetics and isotherm were also evaluated. The results showed that the obtained zeolite has potential for applying as low-cost adsorbent for the removal of BG from wastewater with higher than 97% adsorption efficiency.
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Suga, Yuki, Ryosuke Takagi, and Hideto Matsuyama. "Recovery of Valuable Solutes from Organic Solvent/Water Mixtures via Direct Contact Membrane Distillation (DCMD) as a Non-Heated Process." Membranes 11, no. 8 (July 23, 2021): 559. http://dx.doi.org/10.3390/membranes11080559.
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Recently, the demand for the recovery of valuable solutes from organic solvents/water mixtures has increased in various fields. Furthermore, due to the abundance of heat-sensitive valuable solutes, the demand for non-heated concentration technologies has increased. In this study, the direct contact membrane distillation (DCMD) using hydrophobic polyvinylidene difluoride (PVDF) hollow fiber membranes was investigated to confirm the possibility of recovering valuable solutes from organic solvents/water mixtures as a non-heated process. The DCMD with 1000 ppm NaCl aqueous solution achieved 0.8 kg/m2·h of vapor flux and >99.9% of NaCl retention, even at feed and coolant temperatures of 25 and 10 °C, respectively. Furthermore, when DCMD was conducted under various conditions, including feed temperatures of 25, 35 and 45 °C, and organic solvent concentration of 15, 30 and 50 wt%, using ethanol/water and acetonitrile/water mixtures containing 1000 ppm NaCl. A surfactant was also used as a valuable solute, in addition to NaCl. As a result, it was found that the total vapor flux increased with increasing temperature and concentration of organic solvents, as the partial vapor pressure of the organic solvents increased. Additionally, no solute leaked under any condition, even when the surfactant was used as a valuable solute.
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Santos, Edson Costa, Katsuyuki Kida, Justyna Rozwadowska, Takashi Honda, Koshiro Mizobe, and Takuya Shibukawa. "Microstructure and Rolling Contact Fatigue Strength of Induction Heated AISI 52100 Bearings." Advanced Materials Research 566 (September 2012): 288–92. http://dx.doi.org/10.4028/www.scientific.net/amr.566.288.
Full textAbstract:
In the present work the microstructure and the rolling contact fatigue properties of induction heated AISI 52100 bearings are investigated. The bearings were heat treated by using a flat coil at 30 kW power and 60 kHz frequency, cooled with water and subsequently tempered for 1 hour at 180 °C. The hardness at the surface of the material was close to 900 HV0.3kgf/15s. The hardening depth of the induction heated sample was higher than 5 mm. The retained austenite content was around 18% at the surface and decreases along with the depth. The samples were rolling contact fatigue (RCF) tested up to 107 and 4.5x107 cycles, at Hertzian stress 4 GPa. No flaking failure was observed on the bearing races. For tests up to 107 cycles the track size was around 690 um and this remained unchanged up to 4.5x107 cycles. The residual stresses at the material surface before testing were close to zero and became highly compressive after the RCF testing. Stress induced transformation occurred at the surface and the retained austenite content after testing reached around 10%. Induction heating was successfully applied to induce martensitic transformation in AISI 52100 steel and the bearings showed very high fatigue strength under rolling contact.
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Effendy, Isaak, Harald Loeffler, and Howard I. Maibach. "Baseline transepidermal water loss in patients with acute and healed irritant contact dermatitis." Contact Dermatitis 33, no. 6 (December 1995): 371–74. http://dx.doi.org/10.1111/j.1600-0536.1995.tb02069.x.
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