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1
Huertas, Juan-Pablo, María Ros-Chumillas, Alberto Garre, Pablo S. Fernández, Arantxa Aznar, Asunción Iguaz, Arturo Esnoz, and Alfredo Palop. "Impact of Heating Rates on Alicyclobacillus acidoterrestris Heat Resistance under Non-Isothermal Treatments and Use of Mathematical Modelling to Optimize Orange Juice Processing." Foods 10, no. 7 (June 28, 2021): 1496. http://dx.doi.org/10.3390/foods10071496.
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Alicyclobacillus acidoterrestris is a spoilage microorganism responsible for relevant product and economic losses in the beverage and juice industry. Spores of this microorganism can survive industrial heat treatments and cause spoilage during posterior storage. Therefore, an effective design of processing treatments requires an accurate understanding of the heat resistance of this microorganism. Considering that industrial treatments are dynamic; this understanding must include how the heat resistance of the microorganism is affected by the heating rate during the heating and cooling phases. The main objective of this study was to establish the effect of heating rates and complex thermal treatments on the inactivation kinetics of A. acidoterrestris. Isothermal experiments between 90 and 105 °C were carried out in a Mastia thermoresistometer, as well as four different dynamic treatments. Although most of the inactivation takes place during the holding phase, our results indicate the relevance of the heating phase for the effectiveness of the treatment. The thermal resistance of A. acidoterrestris is affected by the heating rate during the heating phase. Specifically, higher heating rates resulted in an increased microbial inactivation with respect to the one predicted based on isothermal experiments. These results provide novel information regarding the heat response of this microorganism, which can be valuable for the design of effective heat treatments to improve product safety and stability. Moreover, it highlights the need to incorporate experimental data based on dynamic treatments in process design, as heating rates can have a very significant effect on the thermal resistance of microorganisms.
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ARCHER, JULIE, EMMA T. JERVIS, JON BIRD, and JOY E. GAZE. "Heat Resistance of Salmonella weltevreden in Low-Moisture Environments." Journal of Food Protection 61, no. 8 (August 1, 1998): 969–73. http://dx.doi.org/10.4315/0362-028x-61.8.969.
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The heat resistance of Salmonella weltevreden inoculated into flour and heated in hot air was determined for (a) an initial water activity (aw) range of 0.20 to 0.60 prior to heating, (b) a range of storage relative humidities of 6.0 to 35.5% prior to heating, and (c) temperatures of 57 to 77°C. The death curves obtained were biphasic, demonstrating an initial rapid decline in the numbers of survivors (1.0- to 1.5-log reductions) during the first 5 to 10 min of heating for all the temperature-water activity combinations tested. Following this initial rapid decline in the number of cells, a linear survivor curve was obtained where inactivation occurred at a slower rate. The initial decline in survivors coincided with a rapid decrease in the water activity of all the samples tested. Irrespective of the initial water activity level in the samples prior to heating, the aw decreased to <0.2 during the first 5 to 10 min of heating. The D values obtained for these experimental parameters ranged from a D60–62 of 875 min at an initial aw of 0.4 to a D63–65 of 29 min at an initial aw of 0.5. The results demonstrated that, for any temperature, as the initial water activity of the sample prior to heating decreased, the heat resistance of the cells increased. The z values obtained from these data ranged from 15.2 to 53.9°C. The relative humidity during storage prior to heating did not appear to have a significant effect on the heat resistance of S. weltevreden in flour. These results demonstrate that the amount of available water in foods that are considered to be “dry” (i.e., with a water activity less than 0.60) will significantly influence the effectiveness of the heat processing of foods and, in addition to the temperature, the aw prior to heating is a critical controlling factor during these processes.
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Lehotová, Veronika, Karla Miháliková, Alžbeta Medveďová, and Ľubomír Valík. "Modelling the inactivation of Staphylococcus aureusat moderate heating temperatures." Czech Journal of Food Sciences 39, No. 1 (February 26, 2021): 42–48. http://dx.doi.org/10.17221/201/2020-cjfs.
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The survival of bacterial contaminants at moderate processing temperatures is of interest to many food producers, especially in terms of the safety and quality of the final products. That is why the heat resistance of Staphylococcus aureus 2064, an isolate from artisanal Slovakian cheese, was studied in the moderate temperature range (57–61 °C) by the capillary method. The fourth decimal reduction time t<sub>4D</sub>- and z-values were estimated in two steps by traditional log-linear Bigelow and non-linear Weibull models. In addition, a one-step fitting procedure using the Weibull model was also applied. All the approaches provided comparable t<sub>4D</sub>-values resulting in the following z-values of 11.8 °C, 12.3 °C and 11.3 °C, respectively. Moreover, the one-step approach takes all the primary data into z-value calculation at once, thus providing a more representative output at the reasonable high coefficient of determination R<sub>2</sub> = 0.961
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Donskoy, Igor, and Aleksandr Kozlov. "Thermogravimetric Study of the Kinetics of the Reaction C + CO2 under Pore-Diffusion Control." Energies 14, no. 7 (March 29, 2021): 1886. http://dx.doi.org/10.3390/en14071886.
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This study presents experimental studies of charcoal gasification with CO2 at different heating rates (1, 5, 10, 20, and 50 K min−1). The kinetics of the reaction C + CO2 under pore-diffusion control is studied. We propose a new method for the proper determination of activation energy during the processing of thermogravimetric curves of porous carbon gasification under conditions of pore-diffusion resistance. The results of the inverse kinetic problem solution are compared with different hypotheses about the regime of the investigated heterogeneous reaction process (kinetic, diffusion, pore-diffusion). The change of reaction regimes from kinetic to diffusion is detected during charcoal gasification at different heating rates. At heating rates of 5–20 K min−1, the values of activation energy of carbon gasification reaction in the carbon dioxide atmosphere, obtained by the proposed method, closely match the data found in the previous studies. The use of diffusion models in the processing of thermogravimetric curves determines the conditions under which conventional kinetic models fail to provide adequate information about the temperature dependence of the heterogeneous reaction rate.
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JUNEJA, VIJAY K., and BRIAN S. EBLEN. "Influence of Sodium Chloride on Thermal Inactivation and Recovery of Nonproteolytic Clostridium botulinum Type B Strain KAP B5 Spores†." Journal of Food Protection 58, no. 7 (July 1, 1995): 813–16. http://dx.doi.org/10.4315/0362-028x-58.7.813.
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Demand for minimally processed refrigerated foods with reduced salt levels has stimulated renewed interest in the potential for survival and growth of psychrotrophic, nonproteolytic Clostridium botulinum type B spores. As part of a project to better define food-processing requirements, the heat resistance (75 to 90°C) of nonproteolytic C. botulinum type B spores was assessed in turkey containing 1 to 3% (wt/vol) salt (sodium chloride). Heated spores were recovered both on reinforced clostridial medium (RCM) with lysozyme and on RCM having the same salt levels as the heating menstruum. When the recovery medium contained no salt, D-values in turkey slurry containing 1% salt were 42.1, 17.1, 7.8, and 1.1 min at 75, 80, 85, and 90°C, respectively. Increasing levels (2 and 3%, wt/vol) of salt in the turkey slurry reduced the heat resistance as evidenced by reduced spore D-values. Also, apparent or measured heat resistance was decreased with increasing salt concentration in the heating menstruum and the recovery medium. The z-values in turkey slurry for all treatments were similar, ranging from 8.47 10 10.08°C.These data will assist food processors to design thermal processes that ensure safety against nonproteolytic C. botulinum type B spores in cook/chill foods while minimizing quality losses.
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Febraldo, David, Wayan Nata Septiadi, and Ketut Astawa. "Kinerja Termal Pipa Kalor Tembaga pada Fluida Kerja Air." Jurnal METTEK 5, no. 1 (April 30, 2019): 52. http://dx.doi.org/10.24843/mettek.2019.v05.i01.p07.
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Pipa kalor (Heat pipe) merupakan salah satu teknologi penukar kalor dua fase sistem pasif, pipa kalor itu sendiri memiliki struktur dengan konduktivitas termal tinggi, hal ini memungkinkan transportasi panas dengan mempertahankan perbedaan suhu sehingga seragam di sepanjang bagian yang dipanaskan dan didinginkan. Kinerja termal pipa kalor dapat ditentukan dari nilai hambatan panas. Ketika hambatan panas bernilai kecil, maka laju perpindahan kalor meningkat begitu pula sebaliknya. Pengujian kinerja termal pipa kalor tembaga pada fluida kerja air telah dilakukan. Kinerja termal dapat diamati dari hasil pengambilan data temperatur dan pengolahan data. Hasil dari penelitian ini menunjukkan perbedaan temperatur antara temperatur pemanas dan dan temperatur fluida terus meningkat dengan kenaikan laju perpindahan panas dari variasi beban pemanasan 70 volt, 90 volt, 110 vot, 130 volt, dan 150 volt.
Heat pipe is a passive two-phase heat exchanger technology, heat pipe itself has a structure with high thermal conductivity, this allows heat transportation by maintaining a uniform temperature difference along the heated and cooled part. Thermal performance of heat pipes can be determined from the value of heat resistance. When heat resistance is small, the heat transfer rate increases and vice versa. Testing the thermal performance of copper heat pipes on the working fluid of water has been carried out. Thermal performance can be observed from the results of temperature data collection and data processing. The results of this study indicate the temperature difference between heating temperature and fluid temperature continues to increase with increasing heat transfer rates from variations in heating loads of 70 volts, 90 volts, 110 vot, 130 volts, and 150 volts.
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Sinitsyn, N. N., and N. V. Telin. "Mathematical Modeling of the Bark Drying Process." Lesnoy Zhurnal (Forestry Journal), no. 6 (December 10, 2020): 159–71. http://dx.doi.org/10.37482/0536-1036-2020-6-159-171.
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Currently, a large amount of wood bark waste is generated at the timber processing enterprises of the Russian Federation, which is not widely used in industry and has a negative impact on the environment. One of the feasible directions for the processing of such waste is its burning in layered furnaces. However, tree bark, due to its high moisture content and extremely heterogeneous fractional composition, belongs to a low-energy, difficult-to-burn fuel. High humidity reduces the energy density of the bark. The extremely heterogeneous fractional composition of tree bark (linear dimensions of random bark chips can vary from millimeters to tens of centimeters) complicates the organization of the burning process. Effective utilization of tree bark is ensured when it is pre-dried to a moisture content of 55–60 % and the size of bark chips not exceeding 100 mm. The purpose of the presented work is to study the temperature field in a dense blown layer of high-moisture bark when drying it with high-temperature flue gases from boiler units. A mathematical model for heating the dense layer of high moisture tree bark has been developed based on the physics analysis. It was done taking into account the assessment of the bark dense layer thickness, which uses the method of calculating the aerodynamic resistance of a transversely blown layer to a gas flow. Numerical experiments were carried out in order to calculate the temperature fields during the heating of a single chip of high moisture tree bark located in the front part of the dense blown layer. The calculation data were compared with the results obtained using the developed model. A procedure that allows calculating the total duration of heating the wet material until the layer is completely dry, the time spent on heating the blown dense layer until the complete release of volatile substances, and the temperature fields in the bark layer and gas flow has been developed on the basis of mathematical modeling of the process of the dense layer heating and thermal preparation of high moisture tree bark for burning. A scheme for preparing high moisture tree bark for burning and a method for determining the characteristic parameters of a two-stage scheme of energy use of high moisture tree bark in layered furnaces of boilers and heat generators are proposed.
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SAMAPUNDO, S., M. HEYNDRICKX, R. XHAFERI, and F. DEVLIEGHERE. "Validated Empirical Models Describing the Combined Effect of Water Activity and pH on the Heat Resistance of Spores of a Psychrotolerant Bacillus cereus Strain in Broth and Béchamel Sauce." Journal of Food Protection 74, no. 10 (October 1, 2011): 1662–69. http://dx.doi.org/10.4315/0362-028x.jfp-11-041.
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The major objective of this study was to evaluate and model the combined effect of the water activity (aw) and pH of the heating menstrum on the heat resistance of spores of a psychrotolerant Bacillus cereus strain isolated from béchamel sauce. Two models, a quadratic polynomial equation and a reparameterized function, were assessed for their ability to describe the combined influence of aw and pH on the D85°C-values of the B. cereus isolate in tryptone soy broth. The performance of the models was validated by challenging the models with data independently collected in broth and béchamel sauce. Both models were found to adequately describe the validation data obtained in broth. However, it was determined that in béchamel sauce the predictions of the polynomial function not only showed bias (bias factor = 1.156) but were also fail-dangerous, as they deviated from the validation data by 17.2%. The reparameterized function was determined to be a good predictor of the D85°C-values in béchamel sauce as it showed no bias (bias factor = 1.033) and its predictions differed by only 7.9% from the validation data. The reparameterized function can be used to provide estimates of the minimum processing conditions required to achieve desired levels of spore inactivation within the aw and pH ranges studied and to determine the potential changes in heat resistance of B. cereus spores when aw and pH are changed, for example, during product reformulation. As validation of heat resistance models is rarely performed, let alone in actual food products, the models evaluated and validated in this study (in particular the reparameterized function) are of immediate relevance to the food industry.
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Achiţei, Dragoş Cristian, Petrică Vizureanu, Mirabela Georgiana Minciună, Mohd Mustafa Al Bakri Abdullah, and Ioan Gabriel Sandu. "Study on Al-Si Alloys Properties Enhancement." Applied Mechanics and Materials 754-755 (April 2015): 634–38. http://dx.doi.org/10.4028/www.scientific.net/amm.754-755.634.
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The paper presents a study about aluminum alloy, allied with Si, Cu, Mn, Mg. The Al-Si-Cu-Mg alloys for foundry are used for parts strongly required and which work at high temperatures, due to their good wear resistance. The industrial Al-Cu alloys contain 12 % cooper, are hipo-eutectic and may be for foundry or deformable. By alloying with magnesium, the Al-Cu alloys become with remarkable properties of resistance and plastic deformation processing. The improvement of mechanical characteristics for Al-Si alloys is realized with metals which forms the intermediate phases with silicon or aluminum, with variable solubility in solid state and which permits the structural hardening by heat treatments (quenching and ageing). From the analysis of dilatogramms, grouped for each sample, with the specific initial length, subjected to successive heating, from ambiance temperature up to 500°C, it is found that, with the appearance of ageing phenomena, on the samples aren’t significant modifications for elongation (few microns), only different may be the form of elongation-temperature curve. This analysis permits the determination of experimental data, regarding the behavior of Al-Si alloy subjected to heat treatments and repeated warming. Therefore, the Al-Si-Cu-Mg alloys, for foundry, are used for manufacture the parts strong required and which work at high temperatures, like pistons for engines with internal burn, parts for machines and reinforcements construction, due to their high usage resistance.
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Metzger, Stefan, George Burba, Sean P. Burns, Peter D. Blanken, Jiahong Li, Hongyan Luo, and Rommel C. Zulueta. "Optimization of an enclosed gas analyzer sampling system for measuring eddy covariance fluxes of H<sub>2</sub>O and CO<sub>2</sub>." Atmospheric Measurement Techniques 9, no. 3 (March 31, 2016): 1341–59. http://dx.doi.org/10.5194/amt-9-1341-2016.
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Abstract. Several initiatives are currently emerging to observe the exchange of energy and matter between the earth's surface and atmosphere standardized over larger space and time domains. For example, the National Ecological Observatory Network (NEON) and the Integrated Carbon Observing System (ICOS) are set to provide the ability of unbiased ecological inference across ecoclimatic zones and decades by deploying highly scalable and robust instruments and data processing. In the construction of these observatories, enclosed infrared gas analyzers are widely employed for eddy covariance applications. While these sensors represent a substantial improvement compared to their open- and closed-path predecessors, remaining high-frequency attenuation varies with site properties and gas sampling systems, and requires correction. Here, we show that components of the gas sampling system can substantially contribute to such high-frequency attenuation, but their effects can be significantly reduced by careful system design. From laboratory tests we determine the frequency at which signal attenuation reaches 50 % for individual parts of the gas sampling system. For different models of rain caps and particulate filters, this frequency falls into ranges of 2.5–16.5 Hz for CO2, 2.4–14.3 Hz for H2O, and 8.3–21.8 Hz for CO2, 1.4–19.9 Hz for H2O, respectively. A short and thin stainless steel intake tube was found to not limit frequency response, with 50 % attenuation occurring at frequencies well above 10 Hz for both H2O and CO2. From field tests we found that heating the intake tube and particulate filter continuously with 4 W was effective, and reduced the occurrence of problematic relative humidity levels (RH > 60 %) by 50 % in the infrared gas analyzer cell. No further improvement of H2O frequency response was found for heating in excess of 4 W. These laboratory and field tests were reconciled using resistor–capacitor theory, and NEON's final gas sampling system was developed on this basis. The design consists of the stainless steel intake tube, a pleated mesh particulate filter and a low-volume rain cap in combination with 4 W of heating and insulation. In comparison to the original design, this reduced the high-frequency attenuation for H2O by ≈ 3∕4, and the remaining cospectral correction did not exceed 3 %, even at high relative humidity (95 %). The standardized design can be used across a wide range of ecoclimates and site layouts, and maximizes practicability due to minimal flow resistance and maintenance needs. Furthermore, due to minimal high-frequency spectral loss, it supports the routine application of adaptive correction procedures, and enables largely automated data processing across sites.
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Metzger, S., G. Burba, S. P. Burns, P. D. Blanken, J. Li, H. Luo, and R. C. Zulueta. "Optimization of a gas sampling system for measuring eddy-covariance fluxes of H<sub>2</sub>O and CO<sub>2</sub>." Atmospheric Measurement Techniques Discussions 8, no. 10 (October 26, 2015): 10983–1028. http://dx.doi.org/10.5194/amtd-8-10983-2015.
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Abstract. Several initiatives are currently emerging to observe the exchange of energy and matter between the earth's surface and atmosphere standardized over larger space and time domains. For example, the National Ecological Observatory Network (NEON) and the Integrated Carbon Observing System (ICOS) will provide the ability of unbiased ecological inference across eco-climatic zones and decades by deploying highly scalable and robust instruments and data processing. In the construction of these observatories, enclosed infrared gas analysers are widely employed for eddy-covariance applications. While these sensors represent a substantial improvement compared to their open- and closed-path predecessors, remaining high-frequency attenuation varies with site properties, and requires correction. Here, we show that the gas sampling system substantially contributes to high-frequency attenuation, which can be minimized by careful design. From laboratory tests we determine the frequency at which signal attenuation reaches 50 % for individual parts of the gas sampling system. For different models of rain caps and particulate filters, this frequency falls into ranges of 2.5–16.5 Hz for CO2, 2.4–14.3 Hz for H2O, and 8.3–21.8 Hz for CO2, 1.4–19.9 Hz for H2O, respectively. A short and thin stainless steel intake tube was found to not limit frequency response, with 50 % attenuation occurring at frequencies well above 10 Hz for both H2O and CO2. From field tests we found that heating the intake tube and particulate filter continuously with 4 W was effective, and reduced the occurrence of problematic relative humidity levels (RH > 60 %) by 50 % in the infrared gas analyser cell. No further improvement of H2O frequency response was found for heating in excess of 4 W. These laboratory and field tests were reconciled using resistor-capacitor theory, and NEON's final gas sampling system was developed on this basis. The design consists of the stainless steel intake tube, a pleated mesh particulate filter, and a low-volume rain cap in combination with 4 W of heating and insulation. In comparison to the original design, this reduced the high-frequency attenuation for H2O by &approx; 3/4, and the remaining cospectral correction did not exceed 3 %, even at a very high relative humidity (95 %). This standardized design can be used across a wide range of eco-climates and site layouts, and maximizes practicability due to minimal flow resistance and maintenance needs. Furthermore, due to minimal high-frequency spectral loss, it supports the routine application of adaptive correction procedures, and enables more automated data processing across sites.
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Asatov, Nurmuhamat, Mirjalol Tillayev, and Navruzbek Raxmonov. "Parameters of heat treatment increased concrete strength at its watertightness." E3S Web of Conferences 97 (2019): 02021. http://dx.doi.org/10.1051/e3sconf/20199702021.
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One of the effective methods of land irrigation in the Republic of Uzbekistan is carried out with the help of precast reinforced concrete trays of irrigation systems. In the process of operation, precast concrete trays are influenced by difficult operating conditions. As is known, to achieve high water resistance and concrete strength after heat treatment, it is necessary to take into account such factors as pre-exposure time, temperature rise rate, and isothermal warm-up time. However, the determining factor that has the greatest impact on the water resistance of concrete during heat treatment is the duration of the preliminary exposure and the rate of temperature rise, on which the values of internal stresses in concrete depend on heating. The paper gives the results of scientific research, which, being based on the studies of heat and moisture treatment of concrete in a laboratory steam chamber with automatic control of the regime. Scientific methods and techniques were used in the process of data processing and study findings: systematic approach, methods of system analysis and mathematical statistics. To determine the strength of concrete, cubic samples were made with dimensions of 100×100×100 mm, which were tested at the period of 1,3,7,28 days. After HMT compared with similar characteristics of normal hardening samples. The results of studies of the kinetics of increase in concrete strength depending on the heat treatment regimes are shown in the paper, that, despite the slight difference in the duration of the preliminary curing (1 and 2 hours), there is still a certain difference between them. The scientific novelty lies in the formulation, formalization and solving problems related to water resistance, frost resistance, and at the same time saves heat and power resources of trays.
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Butot, S., T. Putallaz, R. Amoroso, and G. Sánchez. "Inactivation of Enteric Viruses in Minimally Processed Berries and Herbs." Applied and Environmental Microbiology 75, no. 12 (April 24, 2009): 4155–61. http://dx.doi.org/10.1128/aem.00182-09.
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ABSTRACT Several hepatitis A virus (HAV) and human norovirus (HuNoV) outbreaks due to consumption of contaminated berries and vegetables have recently been reported. Model experiments were performed to determine the effectiveness of freeze-drying, freeze-drying combined with heating, and steam blanching for inactivation of enteric viruses that might be present on the surface of berries and herbs. Inactivation of HAV and inactivation of feline calicivirus, a surrogate for HuNoV, were assessed by viral culturing and quantitative reverse transcription PCR (RT-PCR), whereas HuNoV survival was determined only by quantitative RT-PCR. While freeze-drying barely reduced (<1.3 log10 units) the amount of HAV RNA detected in frozen produce, a greater decline in HAV infectivity was observed. The resistance of HuNoV genogroup I (GI) to freeze-drying was significantly higher than that of HuNoV GII on berries. Addition of a terminal dry heat treatment at 120°C after freeze-drying enhanced virus inactivation by at least 2 log10 units, except for HuNoV GII. The results suggest that steam blanching at 95°C for 2.5 min effectively inactivated infectious enteric viruses if they were present in herbs. Our results provide data for adjusting food processing technologies if viral contamination of raw materials is suspected.
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Mačiulaitis, Romualdas, Andrejus Jefimovas, and Povilas Zdanevičius. "RESEARCH OF NATURAL WOOD COMBUSTION AND CHARRING PROCESSES." Journal of Civil Engineering and Management 18, no. 5 (September 28, 2012): 631–41. http://dx.doi.org/10.3846/13923730.2012.720935.
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Wood is a material widely used for construction purposes and – in some cases – it is the main element of building structures. In comparison with other materials, wood has a number of advantages, such as lightness, strength, resistance to impacts and vibration, simplicity in terms of processing and etc. However, one of the largest drawbacks of wood is flammability. Charring of wooden structures is the most apparent feature of combustion in case of fire in wooden buildings or buildings made of wooden structures. This property is important in identifying causes of fire; therefore it is necessary to relate charring of wooden structures with certain significant effects of fire, such as its duration or temperature. The article addresses the wood characteristics that impact on combustion and charring. It describes test methods and properties of wood samples under research. Research of charring rate of natural softwood and hardwood as a function of heating time, and regressive analysis of data were carried out. Empiric equations were derived. The calorific value of carbon residue resulting in different temperatures was determined in accordance with LST EN ISO 1716. Thermographic research of oak and pine wood was carried out in different gaseous environments. The research results were summarised in the form of conclusions.
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Díaz-Hernández, Heidi Paola, Pablo René Torres-Hernández, Karla María Aguilar-Castro, Edgar Vicente Macias-Melo, and María José Jiménez. "Data-Based RC Dynamic Modelling Incorporating Physical Criteria to Obtain the HLC of In-Use Buildings: Application to a Case Study." Energies 13, no. 2 (January 8, 2020): 313. http://dx.doi.org/10.3390/en13020313.
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This paper reports the application of RC dynamic models (network of resistances and capacitances analogous to electrical networks) to obtain the heat loss coefficient (HLC) from a dynamic test campaign carried out in an in-use building. It is a well-insulated building located in Gainsborough, U.K. This case study and data were made available to participants in the IEA–EBC Annex 71 project Building Energy Performance Assessment Based on In-Situ Measurements. The analysis reported in this paper is mainly focused on the identification of the main heat transfer contributions and also on the translation of these phenomena to the RC models used to obtain the required HLC. First pre-processing and qualitative analysis were carried out. Afterwards several candidate models were constructed according to different plausible assumptions and approximations. The validity of the results obtained using these models has been evaluated taking into account the agreement among different data series and also the levels of the residuals obtained using the different models. The work concludes obtaining accurate estimates of the HLC from the energy balance including the following relevant contributions: space heating, solar gains, internal gains due to appliances, and internal gains due to metabolic activity. These terms were modelled using the following driving variables: consumption of gas and water, electricity production by the photovoltaic (PV) panels and electricity consumption (modelling internal gains due to appliances and occupancy patterns).
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Lobyntsev, V. V., S. S. Polev, and K. G. Mogilevsky. "Study of Performance of RZhFA‑6500 Smoothing Reactors." World of Transport and Transportation 18, no. 4 (January 5, 2021): 72–83. http://dx.doi.org/10.30932/1992-3252-2020-18-72-83.
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DC traction power supply systems have become widespread in several countries. Electricity consumption by traction power supply systems has pronounced seasonal and daily peaks. The peak nature of consumption leads to additional heating of live parts since time constants of transient thermal and electrophysical processes differ by several orders of magnitude, therefore, reducing ohmic resistance of electrical equipment, other things being equal, is an extremely important task.Within the framework of solving the problem of increasing energy efficiency of equipment of DC traction substations, smoothing reactor filter devices with an armoured radial-cylindrical magnetic core with low ohmic resistance, named RZhFA‑6500, were developed and manufactured.In 2018, two blocks of RZhFA‑6500 smoothing reactors were put into pilot operation at one of the most heavily loaded sections of DC electrified railways, providing traffic of trains weighing up to 9000 tons and traffic volume of about a hundred pairs of trains per day.To determine comparative indicators of energy efficiency, data on consumption of electric power for traction of trains for the compared periods before and after introduction of smoothing reactors of a new type were requested. The data received from JSC Russian Railways contained information on the traffic volume, type of rolling stock, and weight of the transported goods in accordance with the executed traffic schedule through section under consideration. The resulting set of data served as the basis for development of a multivariate methodology for assessing energy efficiency of reactors of a new type, as well as their contribution to efficiency of train operation over the considered comparative time interval. Since efficiency of power equipment also depends on the ambient temperature, the average integral parameter of average daily temperature was introduced into the calculation methodology, which, as it turned out, during processing initial data and construction of characteristic graphical dependencies, has a comparative difference of less than one percent for the same monitored periods.Accurate quantitative accounting of the data on consumption of electrical energy provided for traction of trains, exchange of reactive energy with the supply network, volume of transportation allowed to obtain an objective comparison of contribution of smoothing reactors of a new type to increasing efficiency of train operation and reducing consumption of electrical energy for traction of trains.
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Umanskii, A. A., A. V. Golovatenko, A. S. Simachev, V. V. Dorofeev, and T. N. Oskolkova. "Plasticity and deformation resistance of the alloyed rail steels in rolling temperature interval." Izvestiya. Ferrous Metallurgy 62, no. 6 (June 28, 2019): 452–60. http://dx.doi.org/10.17073/0368-0797-2019-6-452-460.
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On the basis of conducted experimental studies, regularities of the influence of temperature-speed rolling conditions on the plasticity and deformation resistance in the zones of continuously cast billets of alloy rail steels of E76KhF, E76KhSF grades are determined and scientifically substantiated. The results indicate the complex nature of dependence of rail steel E76KhF plasticity on deformation temperature. In particular, for near-surface layers of continuously cast billets, a noticeable decrease in plasticity in the temperature range of 1025 – 1075 °Cwas recorded, which is absent for the layers located in central zone of that billets. Generalization of the results of plasticity studies of various layers of continuously cast rail E76KhF steel billets has shown that absolute values of the plasticity criterion are significantly reduced with the distance from the surface to the central zone. This fact can be explained by a coarse-grained structure and increased concentration of non-metallic inclusions in the central zone of continuously cast billets relative to their surface layers; it was confirmed by the results of metallographic studies. In particular, it was found that the average grains diameter in the surface layer of deformed continuously cast billets is in 1.3 – 2.1 times less compared to the central zone. There was confirmed the presence of significant concentrations of non-deformable inclusions of the silicate type (Al2O3· SiO2 ; FeO·SiO2 ; MnO·SiO2 ), which have most negative influence on steel plasticity while in the surface area such inclusions are absent. On the basis of conducted researches it was established that with increase in deformation temperature of rail steel E76KhSF there is a decrease in resistance to plastic deformation according to the exponential law. In this case, absolute values of the steel deformation resistance are reduced with the distance from the surface to the central zone of continuously cast billets, which is associated with the above illustrated increase in grain size and localization of non-metallic inclusions. The revealed tendency to reduce the deformation resistance from the surface layers to the center of continuously cast billets is maintained regardless to deformation rate, while the absolute values of the deformation resistance increase significantly with the growth of deformation rate from 1 to 10 s–1. Mathematical processing of the obtained experimental data allowed to obtain regression equations that help to predict plastic and deformation properties of alloyed rail steels of E76KhF and E76KhSF grades with a sufficient degree of reliability under the specified rolling conditions and are complex theoretical basis for the development and improvement of new heating modes of billets for rolling and rail rolling schemes. Adequacy of the obtained experimental dependences is confirmed by results of pilot industrial testing of the new mode of railway rails production on the universal rail mill of “EVRAZ ZSMK”.
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Kozyrev, N. A., R. A. Shevchenko, A. A. Usol’tsev, and A. N. Prudnikov. "Welding of differentially heat-strengthened rails. Laboratory studies." Izvestiya. Ferrous Metallurgy 63, no. 7 (October 5, 2020): 504–11. http://dx.doi.org/10.17073/0368-0797-2020-7-504-511.
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In laboratory conditions, influence of modes of welding with subsequent isothermal holding on quality parameters of welded joint was studied on rail steel samples. Samples were welded with pulses of alternating electric current after welding. Welding was carried out on MS-2008M resistance butt welding machine with a number of alterations of control actions. To measure temperature of the metal in heat affected zone (HAZ), chromel-alumel thermocouples were used. Collection and processing of data from thermocouples was carried out using TEMPOL measuring complex. Temperature of the weld (where it is not possible to install a thermocouple) was measured using HotFind-D thermal imager. Experimental results and physicomechanical properties of the samples are presented: HB hardness, HAZ length, yield strength, tensile strength, ultimate elongation, contraction ratio, and presence of non-metallic inclusions in weld metal. Deviations of hardness were calculated in comparison with the requirements established by GOST R 51685 – 2013 state standard on the surface of samples’ welded joints: decrease-increase and total deviation of hardness. Method of resistant butt welding is proposed, which makes it possible to obtain welded joint of items produced of rail steel with a uniform distribution of hardness and small zone of thermal influence. Dependence of microhardness on volume fraction of structural components was determined. Models of impact of pulsed contact post-welding heating parameters on lowering hardness of weld metal compared to the base metal and on the extent of heat-affected zone were constructed. The proposed method allows us to adjust structure of metal welded joints of rails without additional local heat treatment.
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Dick, Kris J., and Jeremy Pinkos. "Thermal, Moisture and Energy Performance of a Hempcrete Test Structure in the Northern Prairie Climate of Manitoba, Canada." Key Engineering Materials 600 (March 2014): 475–82. http://dx.doi.org/10.4028/www.scientific.net/kem.600.475.
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The processing of industrial hemp, cannabis sativa, results in three basic constituents seed, fibre, and hurd. Within Manitoba the main focus is with seed and oil products. When considering the entire plant approximately 60-70% is the predominantly cellulose woody core called the hurd. A combination of hemp hurd, a binder and water in various proportions is used in the construction of buildings referred to as hempcrete. Hempcrete is used as an environmental barrier providing resistance to heat transfer and to manage moisture of the building envelope. Engineering and architectural designers practicing in the field of non-conventional material applications have clearly indicated a need for design data. This paper presents a portion of research data collected over the past 18 months from a 23.8 m2 (256 ft2) test building on the campus of the University of Manitoba at the Alternative Village. The design temperatures for this location range from-35°C to +32°C. The structure was built using 300 mm thick pre-fabricated hempcrete panels. In addition to indoor and exterior ambient conditions, the temperature is monitored at 40 locations within the envelope - at the interior, middle and exterior providing a profile through the wall system. Similarly, the relative humidity is monitored within the wall and used in conjunction with a sorption isotherm to estimate the moisture content within the assembly. The building is kept at a constant temperature during the heating season with the energy consumption monitored continuously. This building is one of several on the test site that are all identical in terms of size and configuration. This paper will provide a comparison between the thermal, moisture and energy performance of the hempcrete structure and a conventional wood frame, batt-insulated building that represents the vernacular construction in Manitoba.
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Румянцев, А. В., М. А. Никишин, and А. П. Синицин. "Измерение бесконтактным методом удельного электрического сопротивления листового металла в области высоких температур." Журнал технической физики 90, no. 10 (2020): 1702. http://dx.doi.org/10.21883/jtf.2020.10.49802.348-19.
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Non-contact measurement of electrical resistivity of sheet metal at high temperatures © A.V. Rumyantsev, M.A. Nikishin, A.P. Sinitsin Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia e-mail: albert37@list.ru The developed non-contact method for measuring the electrical resistivity of metals at high temperatures is extended to sheet metal. The theoretical part of the method is supplemented by solving the problem of the power introduced into the sample in the form of a thin-walled cylinder during its induction heating. The essence of the method is the measurement of electromotive forces (EMF) induced by a high-frequency electromagnetic field in two circular contours of different diameters, coaxially located with a cylindrical specimen. The obtained formula for the power introduced into the thin-walled cylinder made it possible to find a function linking the electrical resistivity of the sample material and EMF. From the EMF measured in the experiment, the specific electrical resistance of the sample under study was determined and, as a consequence, the value of the power introduced into the sample. The latter allows one to determine the hemispherical integral degree of blackness of the sample material. The results of an experimental verification of the method on a sample in the form of a thin-walled niobium cylinder are presented. The data obtained within 3% are consistent with the data of other authors, which allows us to recommend the technical use of the method. The experimental techniques for implementing the method and processing its results are presented. Keywords: electrical resistivity, electromagnetic field, electromotive force, skin-layer, sheet metal, high temperature, thin-walled cylinder, power. Rumyantsev A.V. − PhD, professor, I. Kant Baltic Federal University, IKBFU, A. Nevskogo str.14, Kaliningrad, 236041, Russia. E-mail: albert37@list.ru Nikishin M.A. – PhD postgraduate student, I. Kant Baltic Federal University,IKBFU, A. Nevskogo str.14, Kaliningrad, 236041, Russia. E-mail: nikishin.maxim.a@gmail.com Sinitsin A.P. – PhD postgraduate student, I. Kant Baltic Federal University, IKBFU, A. Nevskogo str.14, Kaliningrad, 236041, Russia. E-mail: alekseisinitcin82@yandex.ru
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Moustakidis, Serafeim, Athanasios Anagnostis, Apostolos Chondronasios, Patrik Karlsson, and Kostas Hrissagis. "Excitation-invariant pre-processing of thermographic data." Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability 232, no. 4 (April 23, 2018): 435–46. http://dx.doi.org/10.1177/1748006x18770888.
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There is a large number of industries that make extensive use of composite materials in their respective sectors. This rise in composites’ use has necessitated the development of new non-destructive inspection techniques that focus on manufacturing quality assurance, as well as in-service damage testing. Active infrared thermography is now a popular nondestructive testing method for detecting defects in composite structures. Non-uniform emissivity, uneven heating of the test surface, and variation in thermal properties of the test material are some of the crucial factors in experimental thermography. These unwanted thermal effects are typically coped with the application of a number of well-established thermographic techniques including pulse phase thermography and thermographic signal reconstruction. This article addresses this problem of the induced uneven heating at the pre-processing phase prior to the application of the thermographic processing techniques. To accomplish this, a number of excitation invariant pre-processing techniques were developed and tested in this article addressing the unwanted effect of non-uniform excitation in the collected thermographic data. Various fitting approaches were validated in light of modeling the non-uniform heating effect, and new normalization approaches were proposed following a time-dependent framework. The proposed pre-processing techniques were validated on a testing composite sample with pre-determined defects. The results demonstrated the effectiveness of the proposed processing algorithms in terms of removing the unwanted heat distribution effect along with the signal-to-noise ratio of the produced infrared images.
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Băitanu, Doru Dumitru, Dan Galusca, Dragoş Cristian Achiţei, and Mohd Mustafa Al Bakri Abdullah. "The Improvement of Stainless Steels Processing by Annealing." Applied Mechanics and Materials 754-755 (April 2015): 629–33. http://dx.doi.org/10.4028/www.scientific.net/amm.754-755.629.
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The paper presents a study about the structural modifications induced by heat treatment at the stainless steels, like AISI 321 and AISI 304, frequently used in industrial applications. The principal characteristic of these steels is their bigger corrosion resistance, conferred by chrome and nickel.The addiction of other elements is made for the improvement of corrosion resistance in humid environments (molybdenum and cooper), mechanical characteristics at low and high temperatures (tungsten, molybdenum, niobium and cobalt). The necessary condition to obtaining a high corrosion resistance is that all chrome content to be in forms of solid solution. The precipitation of carbides from solid solution causing a decrease under 12% of chrome content, the structure become bi-phase and the corrosion resistance decrease. For the improvement of machinability may be applied an annealing, with respect of all the treatment parameters, obtaining a micro-hardness decrease.The heating for annealing was made in an electric furnace, type UTTIS, with fixed hearth. The imposed heating speed was 10°C/minute. The decrease of micro-hardness by annealing, permit an easy processing for high alloy steels.
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Miller, Benjamin K., Cory Czarnik, George Vacek, and Stephen Mick. "Real-Time Data Processing and Feedback During In-Situ Heating." Microscopy and Microanalysis 24, S1 (August 2018): 1882–83. http://dx.doi.org/10.1017/s1431927618009893.
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Zhengxing, Men, Wang Menghan, Ma Yaxin, Yue Taiwen, and Liu Ruilin. "Application of Direct Resistance Heating in Hot Forging and Analysis of Processing Parameters based on Thermo-electro-mechanical Coupling FEM." High Temperature Materials and Processes 37, no. 6 (June 26, 2018): 531–38. http://dx.doi.org/10.1515/htmp-2016-0236.
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AbstractA series of experiments were designed in order to directly heat the billet of 42CrMo4 to the forming temperature in the dies prior to forming and continue to heat the billet during the forming process. Processing parameters during heating and forming were investigated by experimental method and thermo-electro-mechanical coupling FEM. The experimental results show that prior to forming the billet could be rapidly heated to forming temperature under relatively low initial contact pressure, and the heating temperature was proportional to the square of the current intensity. When the heating current remained constant, the heating temperature could not increase with heating time. During the forming process, the billet cooling rate slowed down and the forming time was extended due to the continuous resistance heating during forming. Finally, an incrementally coupled thermo-electro-mechanical model has been developed to analyze the hot-forging process by direct resistance heating. To obtain the transient temperature field prior to forming, a simple model of contact resistance was used in the thermal-electrical simulation, in which the electrical conductance of the contact resistance was proportional to the heating temperature. Contrasted the experimental results and the simulation results, it was found that they coincided well.
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Ramakrishnan, B., L. Zhu, and R. Pitchumani. "Curing of Composites Using Internal Resistive Heating." Journal of Manufacturing Science and Engineering 122, no. 1 (June 1, 1999): 124–31. http://dx.doi.org/10.1115/1.538913.
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Curing of fiber-resin mixtures is often the critical and productivity controlling step in the fabrication of thermosetting-matrix composites. The long processing times (and costs) have remained the fundamental impediment to widespread commercialization of composites. Shortening the cure cycle time, while ensuring a complete and uniform cure in the product, is imperative for realizing the goal of affordable materials processing, and forms the focus of this investigation. Toward addressing the affordability challenge, this paper explores the use of conductive carbon mats embedded inside the composite as a means of providing internal volumetric resistance heating during the cure process. The supplemental heating results in temperature and cure uniformity through the cross section, as well as speeds up the cure process. In the context of application to resin transfer molding, systematic experimental and theoretical studies on various resistive heating configurations are presented. Optimum processing strategies are derived based on the cure time and microstructural product quality considerations. [S1087-1357(00)01101-1]
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Ullman, David S., and David Hebert. "Processing of Underway CTD Data." Journal of Atmospheric and Oceanic Technology 31, no. 4 (April 1, 2014): 984–98. http://dx.doi.org/10.1175/jtech-d-13-00200.1.
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Abstract A processing methodology for computation of accurate salinity from measurements with an underway CTD (UCTD) is presented. The UCTD is a rapidly profiling sensor package lacking a pump that relies on instrument motion to produce flow through the conductivity cell. With variable instrument descent rate, the flow through the cell is not constant, and this has important implications for the processing. As expected, the misalignment of the raw temperature and conductivity is found to be a function of the instrument descent rate. Application of a constant temporal advance of conductivity or temperature as is done with pumped CTDs is shown to produce unacceptable salinity spiking. With the descent rate of the UCTD reaching upwards of 4 dbar s−1, the effect of viscous heating of the thermistor is shown to produce a significant salinity error of up to 0.005 psu, and a correction based on previous laboratory work is applied. Correction of the error due to the thermal mass of the conductivity cell is achieved using a previously developed methodology with the correction parameters varying with instrument descent rate. Comparison of salinity from the UCTD with that from a standard shipboard, pumped CTD in side-by-side deployments indicates that the processed UCTD salinity is accurate to better than 0.01 psu.
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Plantin, Jean-Christophe. "The data archive as factory: Alienation and resistance of data processors." Big Data & Society 8, no. 1 (January 2021): 205395172110075. http://dx.doi.org/10.1177/20539517211007510.
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Archival data processing consists of cleaning and formatting data between the moment a dataset is deposited and its publication on the archive’s website. In this article, I approach data processing by combining scholarship on invisible labor in knowledge infrastructures with a Marxian framework and show the relevance of considering data processing as factory labor. Using this perspective to analyze ethnographic data collected during a six-month participatory observation at a U.S. data archive, I generate a taxonomy of the forms of alienation that data processing generates, but also the types of resistance that processors develop, across four categories: routine, speed, skill, and meaning. This synthetic approach demonstrates, first, that data processing reproduces typical forms of factory worker’s alienation: processors are asked to work along a strict standardized pipeline, at a fast pace, without acquiring substantive skills or having a meaningful involvement in their work. It reveals, second, how data processors resist the alienating nature of this workflow by developing multiple tactics along the same four categories. Seen through this dual lens, data processors are therefore not only invisible workers, but also factory workers who follow and subvert a workflow organized as an assembly line. I conclude by proposing a four-step framework to better value the social contribution of data workers beyond the archive.
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FOEGEDING, P. M., and N. W. STANLEY. "Listeria innocua Transformed with an Antibiotic Resistance Plasmid as a Thermal-resistance Indicator for Listeria monocytogenesa." Journal of Food Protection 54, no. 7 (July 1, 1991): 519–23. http://dx.doi.org/10.4315/0362-028x-54.7.519.
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Listeria innocua PFEI is a chloramphenicol- and erythromycin-resistant organism obtained by electotransforming L. innocua ATCC 33091 with the plasmid pGK12. L. innocua ATCC 33091 and L. innocua PFEI were more heat resistant between 56 and 66°C than Listeria monocytogenes F5069 and Scott A when evaluated in sterile phosphate buffer or milk. Decimal reduction times of each L. innocua strain were 1.5 to 3 times longer in either heating menstruum than were D-values of the most heat resistant L. monocytogenes strain studied (F5069). L. innocua PFEI retained the plasmid during heating so that, of 300 survivors evaluated, 100% were resistant to chloramphenicol and 98% were resistant to erythromycin. Thus, L. innocua ATCC 33091 or PFEI would be useful indicator organisms to evaluate the lethality of thermal processes with respect to L. monocytogenes. L. innocua PFEI has the advantages that it could easily be selected and enumerated among a large, complex, background microflora, but it may not be appropriate for application in a food processing environment.
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Zhu, Xi Lin, and Gang Li. "The Electrothermal Heating Tube Membrane Resistance Test Method Research." Key Engineering Materials 667 (October 2015): 413–18. http://dx.doi.org/10.4028/www.scientific.net/kem.667.413.
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This thesis uses a kind of detection method: The two ends of the measurement period from two electrodes, and the probe spacing can be adjusted. Two measuring end head into the interior with electric heat pipe membrane contact ,used the voltage dividing circuit,relations indirect detection of electric resistance film ends with the two measuring pitch. Then the measured data analysis, obtains the relationship between the two electrode spacing and the electrothermal membrane resistance. Make this thought method may not be used to measure the electric heating film resistance, become a simple and practical method for measuring the electric heating film resistance. Using this method, the measured data can be analyzed, indirectly electrothermal film heating pipe internal resistance value and the two measurement of the end head distance is linear change. The linear relationship between the use of electrothermal film heating tube internal electric heating film resistance, the resistance can be estimated from the distance between the two electrodes, get the change range of heating tube power.
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Qiao, Xiuquan, Budan Wu, Yulong Liu, Zhao Xue, and Junliang Chen. "Event-Driven SOA Based District Heating Service System with Complex Event Processing Capability." International Journal of Web Services Research 11, no. 1 (January 2014): 1–29. http://dx.doi.org/10.4018/ijwsr.2014010101.
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With the management refinement of heating supply, the district heating system deploys a large number of meters or sensors to monitor and control the operating status of the heating network. It often needs to process real-time streaming data and coordinate the related enterprise business systems to make low-latency, intelligent decisions on the changes of heating network in time. Therefore, the automatic collection, on-demand dissemination and fusion of real-time sensing data play an increasingly important role in district heating systems. This article proposed an event-driven SOA based district heating system architecture with complex event processing capability, which can easily support the on-demand dissemination and aggregation of monitoring information and realize the event-driven service coordination cross different service domains. Finally, a deployed District Heating Control and Information Service System (DHCISS) in Beijing validates the effectiveness of our approach.
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Zhu, Xi Lin, Shao Tai Deng, Gang Li, and Yun Piao Li. "The Study of the Electrothermal Heating Pipe Membrane Resistance Test Equipment." Key Engineering Materials 667 (October 2015): 379–84. http://dx.doi.org/10.4028/www.scientific.net/kem.667.379.
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In order to detect the electrothermal heating tube internal electrothermal film resistance and the relationship between the two electrode gap, this thesis used design using a testing equipment: The two ends of the measurement period from two electrodes, and the probe spacing can be adjusted ; The two measuring points into hair heat pipe internal contact with the resistive film, using the bleeder circuit, the indirect measuring resistance membrane resistance and the relationship between the two measuring points spacing; then analyze the measurement data, the relationship between the two electrode gap and electrothermal film resistance. The use of such equipment, the measured data, we can analyze the electrothermal film heating pipe internal heating membrane resistance and two measurement of the end head distance is linear change. The linear relationship between the use of electrothermal film heating tube internal electrothermal membrane resistance, can estimate the range of internal electric heating film heating pipe resistance from two the distance between the electrodes, get the change range of heating tube power.
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Zhu, Song Qing, Jin Fei Shi, and Fei Hao. "Research on the Pavement Performance of Recycled Asphalt Mixture Processed by Microwave." Advanced Materials Research 148-149 (October 2010): 987–93. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.987.
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In order to evaluate the pavement performance of recycled asphalt mixture processed by microwave, an experimental method was designed to compare the microwave heating with the conventional heating in recycling affection of asphalt mixture. The samples AC-13 were produced. Conventional and microwave heating performance of modified asphalt recycling test including the rutting test, the trabecular cold bending test, the Marshall immersion test, the freeze-thaw split test, and the splitting strength mechanical properties were test. The experimental results show that it is roughly the same in the high temperature stability and mechanical properties of these two areas, and at low temperature cracking resistance the use of microwave processing can improve the low temperature flexibility to reduce the surface temperature seasonal prone temperature shrinkage cracks and fatigue cracks. The stability on the water by using microwave processing can enhance the asphalt and aggregate adhesion so that mixture enhanced resistance to water damage, there is a better role in improving the water stability. These results could promote microwave recycling and provide the basis for the promotion applications.
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Ivannikov, A. Yu. "Current state and prospects of the development of electromechanical processing for gas-thermal coatings." Glavnyj mekhanik (Chief Mechanic), no. 1 (January 25, 2021): 49–56. http://dx.doi.org/10.33920/pro-2-2101-07.
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The article presents an overview of the works on electromechanical processing of plasma coatings performed at the Institute of Metallurgy and Materials Science of the Russian Academy of Sciences and VolgSTU. The results of changes in the physical, mechanical and operational properties of plasma-sprayed coatings after electromechanical processing are analyzed. The main approaches in the field of electromechanical processing of gas-thermal coatings are outlined. The use of a cooling liquid to protect the zone of electric contact heating contributes to the preservation of the chemical composition of the coating. High rates of heating and cooling of the local area in the contact zone of the coating and the electrode tool lead to the fixation of the fast-quenched structure in the coating. An increase in the coating temperature as a result of resistive heating with simultaneous surface plastic deformation contributes to a decrease in surface roughness, compaction of the coating and the passage of diffusion welding along the boundaries of the sprayed particles. After electromechanical processing, the coating microhardness, cohesive and adhesive strength, corrosion and wear resistance are increased.
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Cheng, Guang He, Rui Rui Sun, and Lu Yue Han. "Error Processing for Acquisition System of Heating Flux of Building Envelope." Applied Mechanics and Materials 678 (October 2014): 228–32. http://dx.doi.org/10.4028/www.scientific.net/amm.678.228.
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After excluding the usual device error, environmental error caused by electromagnetic interference persists in the acquisition system of heating flux of building envelope. This error makes the system instability and causes relatively large deviations of heat flux data, affecting building energy conservation measurement. To counter the problem of error in the data acquisition system, a new software filtering algorithm is put forward. The algorithm combines the idea of the mean and median filtering method, and specific algorithm formula and algorithm steps are given in this paper. Experimental results showed that the algorithm effectively improved the accuracy of data collection. For example, when I input 1mV into system from the sensor, average error of heat flux was decreased from 5.2% to 0.4%, and the maximum error was less than 2%.
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Zhang, Kai Feng, Jing Yuan Liu, and Chao Li. "Effect of Microstructure on Hot Bulging Deformation for AZ31 Magnesium Alloy Sheet with Resistance Heating." Materials Science Forum 783-786 (May 2014): 537–40. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.537.
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To enhance the heating efficiency and the formability of AZ31 magnesium alloy, the assistance heating method is adopted during the hot bulging process. The free bulging test of coarse grained and fine grained AZ31 magnesium alloy sheet was carried out. During the forming process, the effects of pulse current on the formed sheet combine both thermoelectricity and electro-plasticity. Directional and asymmetrical deformation of the coarse-grained AZ31 magnesium alloy sheet by the effect of pulse current is observed and analyzed. But in the same processing condition, the deformation of fine grained AZ31 magnesium alloy sheet is symmetrical. To investigate the influence of electron wind force on pulse current auxiliary bulging process, the simulation of AZ31 magnesium alloy pulse current auxiliary bulging based on the electron wind force value calculated by mathematical model was performed using the Marc software. The bulging simulation result showed a special phenomenon that the shape of the bulging specimen is unsymmetrical and the dome deviated from the symmetry axis to the side of positive pole. The simulation results were basically consistent with the experimental results. The deformation properties, microstructure characteristics, dislocation movement of the AZ31 magnesium alloy during gas bulging processing by the pulse current are investigated.
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PALOP, ALFREDO, JAVIER RASO, SANTIAGO CONDÓN, and FRANCISCO J. SALA. "Heat Resistance of Bacillus subtilis and Bacillus coagulans: Effect of Sporulation Temperature in Foods With Various Acidulants." Journal of Food Protection 59, no. 5 (May 1, 1996): 487–92. http://dx.doi.org/10.4315/0362-028x-59.5.487.
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The influence of the sporulation temperature (35 and 52°C) on the effect of different acidulants on the heat resistance of Bacillus subtilis and Bacillus coagulans in homogenized tomato and asparagus at pH 4 was investigated. Several acidulants (hydrochloric, citric, acetic, lactic, and malic acids and glucono-ä-lactone) currently used by the canning industry to lower the pH of some vegetables before processing were studied. The sporulation temperature determined the response of these microorganisms to the type of acidulant. While the heat resistance of spores sporulated at 35°C was the same at all heating temperatures tried, regardless the type of acidulant, that of spores sporulated at 52°C was two- to fivefold lower when lactic or acetic acids were used. This decrease in heat resistance was the same at every temperature over the whole range of heating temperatures tested. The z values obtained with each microorganism were the same for a given heating menstruum, regardless the type of acidulant used.
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Shih-Mim Liu and Chi-Chang Tsai. "A method of gray level data processing and heating control for color thermal printers." IEEE Transactions on Consumer Electronics 46, no. 4 (2000): 1148–54. http://dx.doi.org/10.1109/30.920472.
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Dai, Yu Hua, and Xi Wang. "Design and Verification of a Metal 3D Printing Device Based on Contact Resistance Heating." Solid State Phenomena 298 (October 2019): 64–68. http://dx.doi.org/10.4028/www.scientific.net/ssp.298.64.
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As a branch of 3D printing technology, metal 3D printing is an important advanced manufacturing processing method. Metal 3D printing technology has been widely applied in a variety of areas, including the aerospace field, biomedical research and mold manufacturing. This paper proposed a new method for melting metal wires via contact resistance heating. Through the combination of a numerical control technique, a mechanical structure and computer software, a metal 3D printing device was designed based on the principle of fused deposition modeling. The printing nozzle of the device can be heated to over 1400°C in a few minutes. Additionally, we performed experiments with aluminum wire to demonstrate the feasibility of the printing method. The designed consumer-level desktop metal 3D printer cost less than 1500 dollars to fabricate.
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Li, Wei Wei, Li Xin Mo, Ji Lan Fu, Wen Bo Li, Xin Ming Fan, Jun Ran, and Lu Hai Li. "Influence of Post-Processing Methods on the Conductive Properties of Nano-Silver Conductive Ink." Applied Mechanics and Materials 189 (July 2012): 115–18. http://dx.doi.org/10.4028/www.scientific.net/amm.189.115.
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The article prepares the jet ink with nano-silver synthesized by the lab and then adjusts the parameters of the silver colloid to fabricate nano-silver conductive ink suitable for ink-jet. Then patterns are obtained on the photo paper through EPSON ME 70 jet printing, and treated by three post-processing methods include laser sintering, heating, and solution soaking, which measured by four- point probe measurement and observed by SEM. It shows that after treatment the surface resistance of the patterns all decrease obviously. Patterns heated at 120°C for 10min, the resistance is 815mΩ/□, while the surface changes of silver layers can be observed obviously from SEM images. But the surface of the photo paper is destroyed with some bubbles on the coating surface. After 10min of laser sintering, the resistance of the silver layer reaches 890mΩ/□ from infinity. And when immersed in the NaCl solution for 5min, the patterns’ surface resistance decrease to 2.7Ω/□.
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Zhang, Jing Qi, Hong Shuang Di, and Xiao Yu Wang. "Deformation Heating and Its Effect on the Processing Maps of Ti-15-3 Titanium Alloy." Advanced Materials Research 712-715 (June 2013): 58–64. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.58.
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In the present study, deformation heating generated by plastic deformation and its effect on the processing maps of Ti-15-3 titanium alloy were investigated. For this purpose, hot compression tests were performed on a Gleeble-3800 thermo-mechanical simulator in the temperature range of 850-1150 °C and strain rate range of 0.001-10 s1. The temperature rise due to deformation heating was calculated and the as-measured flow curves were corrected for deformation heating. Using the as-measured and corrected flow stress data, the processing maps for Ti-15-3 titanium alloy at a strain of 0.5 were developed on the basis Murty‘s and Babu’s instability criteria. The results show that both the instability maps based the two instability criteria are essentially similar and are characterized by an unstable region occurring at strain rates higher than 0.1 s1for almost the entire temperature range tested. The unstable regions are overestimated from the as-measured data due to the effect of deformation heating, indicating a better workability after correcting the effect of deformation heating. This is further conformed by the analysis based on strain rate sensitivity.
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Uchida, Hiroshi, Koji Shimada, and Takeshi Kawano. "A Method for Data Processing to Obtain High-Quality XCTD Data." Journal of Atmospheric and Oceanic Technology 28, no. 6 (June 1, 2011): 816–26. http://dx.doi.org/10.1175/2011jtecho795.1.
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Abstract A data processing method to obtain high-quality data from an expendable conductivity–temperature–depth (XCTD) profiler is proposed. By adjusting the mismatch of the response time of the temperature and conductivity sensors, systematic error (on the order of −0.05) in XCTD salinity data can be eliminated from regions having a strong vertical temperature gradient (>0.2°C m−1), such as the main thermocline of the nearshore side of the Kuroshio axis and the seasonal thermocline of the subarctic North Pacific. The systematic errors in XCTD depth and temperature data from two cruises were evaluated by comparing the CTD and XCTD data taken simultaneously during each cruise. The XCTD depths were in good agreement with the CTD depths from one cruise, but depth-dependent depth errors from the other cruise were found. The cause of the depth error is unknown but may have occurred because the terminal velocity for the XCTD probes was much less (−0.0428 m s−1) than that provided by the manufacturer for the later cruise. The results suggest that XCTD and expendable bathythermograph (XBT) observations may have a similar depth error because XBT and XCTD do not have pressure sensors, and therefore depth is inferred from the fall rate of the probe. Systematic positive biases (0.018°C on average) were found in XCTD temperature data. The viscous heating effect may contribute to the thermal bias because flow past the XCTD temperature probe is relatively fast (>3 m s−1). Evaluation of XBT/XCTD data by using simultaneous CTD observations data is valuable for validation of statistical corrections of the global XBT/XCTD dataset.
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Lin, Biying, Yufei Zhu, Lihui Zhang, Ruzhen Xu, Xiangyu Guan, Xiaoxi Kou, and Shaojin Wang. "Effect of Physical Structures of Food Matrices on Heat Resistance of Enterococcus faecium NRRL-2356 in Wheat Kernels, Flour and Dough." Foods 9, no. 12 (December 18, 2020): 1890. http://dx.doi.org/10.3390/foods9121890.
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Nonpathogenic surrogate microorganisms, with a similar or slightly higher thermal resistance of the target pathogens, are usually recommended for validating practical pasteurization processes. The aim of this study was to explore a surrogate microorganism in wheat products by comparing the thermal resistance of three common bacteria in wheat kernels and flour. The most heat-resistant Enterococcus faecium NRRL-2356 rather than Salmonella cocktail and Escherichia coli ATCC 25922 was determined when heating at different temperature–time combinations at a fixed heating rate of 5 °C/min in a heating block system. The most heat-resistant pathogen was selected to investigate the influences of physical structures of food matrices. The results indicated that the heat resistance of E. faecium was influenced by physical structures of food matrices and reduced at wheat kernel structural conditions. The inactivation of E. faecium was better fitted in the Weibull distribution model for wheat dough structural conditions while in first-order kinetics for wheat kernel and flour structural conditions due to the changes of physical structures during heating. A better pasteurization effect could be achieved in wheat kernel structure in this study, which may provide technical support for thermal inactivation of pathogens in wheat-based food processing.
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Evangelisti, Luca, Claudia Guattari, and Francesco Asdrubali. "Influence of heating systems on thermal transmittance evaluations: Simulations, experimental measurements and data post-processing." Energy and Buildings 168 (June 2018): 180–90. http://dx.doi.org/10.1016/j.enbuild.2018.03.032.
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Muenstermann, Simon, Krishna Uibel, Thorsten Tonnesen, and Rainer Telle. "Development of a Self-Heating Ceramic Tool for the Thixoextrusion of High Melting Point Alloys." Solid State Phenomena 116-117 (October 2006): 696–99. http://dx.doi.org/10.4028/www.scientific.net/ssp.116-117.696.
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A novel ceramic tool concept allows near-isothermal steel thixoextrusion experiments. Thermal shock impacts are successfully eliminated from the load profile of conventional semi-solid processing technologies of high melting point alloys. Thus, the application of thermal shock sensitive oxide ceramics exhibiting excellent corrosion resistance as forming dies is feasible. Extruded steel parts show high shape accuracy at very low extrusion forces.
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Lachhab, Fadwa, Mohamed Bakhouya, Radouane Ouladsine, and Mohammed Essaaidi. "A context-driven platform using Internet of things and data stream processing for heating, ventilation and air conditioning systems control." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 233, no. 7 (April 9, 2019): 877–88. http://dx.doi.org/10.1177/0959651819841534.
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Control approaches of heating, ventilation and air conditioning systems in buildings have been proposed in the past years for minimizing energy consumption and maintaining occupants’ comfort. However, recent studies have shown that context-driven control approaches using Internet of things and data stream processing technologies could further improve energy saving in heating, ventilation and air conditioning systems. In this article, an intelligent control approach using a state feedback technique is introduced to regulate the heating, ventilation and air conditioning system according to the actual context. The proposed thermal state feedback control was then implemented and deployed in our EEBLab to study its effectiveness in a real-setting scenario. The performance of the proposed control was evaluated in a real test-site by deploying a control card that links the controller with the heating, ventilation and air conditioning system. A smart mobile application for real feedback control was also developed and deployed to dynamically adapt the controller to context’s changes. The mobile application and the heating, ventilation and air conditioning system communicate and exchange data under a data acquisition and visualization platform. In this article, a holistic platform that combines Internet of things and data stream processing technologies was developed and deployed in a real-setting scenario. Experiments have been performed, and results are reported to demonstrate the effectiveness and usefulness of the proposed approach in terms of energy saving while maintaining a comfortable room temperature. The proposed state feedback control outperforms the proportional–integral–derivative and ON/OFF approaches in terms of energy consumption while providing acceptable thermal comfort by allowing a neutral thermal sensation with ± 0.30 of predictive mean vote and less than 7% of predicted percentage of dissatisfaction.
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Ternero, Fátima, Raquel Astacio, Eduardo S. Caballero, Francisco G. Cuevas, and Juan M. Montes. "Influence of Processing Parameters on the Conduct of Electrical Resistance Sintering of Iron Powders." Metals 10, no. 4 (April 22, 2020): 540. http://dx.doi.org/10.3390/met10040540.
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The influence of the applied pressure and electrical parameters on the macrostructure of specimens consolidated by the medium-frequency electrical resistance sintering technique (MF-ERS) is analysed in this work. This technique is based on the application of pressure to a mass of conductive powder that, simultaneously, is being crossed by a high intensity and low voltage electric current. The simultaneous action of the pressure and the heat released by the Joule effect causes the densification and consolidation of the powder mass in a very short time. The effect of the current intensity and heating time on the global porosity, the porosity distribution, and the microhardness of sintered compacts is studied for two applied pressures (100 and 150 MPa). For the different experiments of electrical consolidation, a commercially available pure iron powder was chosen. For comparison purposes, the properties of the compacts consolidated by MF-ERS are compared with the results obtained by the conventional powder metallurgy route (cold pressing and furnace sintering). Results show that, as expected, higher current intensities and dwelling times, as well as higher pressures and the consolidation of compacts with lower aspects ratios, produce denser materials.
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Kim, W., J. Riikonen, S. Arpiainen, O. Svensk, C. Li, and H. Lipsanen. "Growth of CVD graphene on copper by rapid thermal processing." MRS Proceedings 1451 (2012): 27–32. http://dx.doi.org/10.1557/opl.2012.1333.
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ABSTRACTWe have investigated the fabrication of graphene by chemical vapor deposition using a conventional rapid thermal processing system with infrared heating. Graphene films were grown on the pretreated copper foil in RTP at 935-960°C at pressure of 6~7 mbar. The grown films were characterized by scanning electron microscope and Raman spectroscopy to investigate morphology of graphene. The growth of graphene was initiated by small flakes that spread rapidly covering the whole copper surface as a single-layer film in ~20 seconds. Room temperature mobility and sheet resistance extracted by transfer-length method (TLM) for the graphene film transferred onto the SiO2/Si substrate were around 1,800 cm2/Vs and 260 Ω/ð with the gate voltage, respectively.
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Safdar, S., L. Li, M. A. Sheikh, and M. J. Schmidt. "Thermal history analysis of surface heating of mild steel with different laser beam geometries." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 220, no. 10 (October 1, 2006): 1549–57. http://dx.doi.org/10.1243/09544062jmes246.
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Lasers are in use in the material processing industry for well over 30 years now. The way in which the temperature is distributed inside the material is of prime importance in laser material processing, as it directly affects the heating/cooling rates and thermal gradients. Optimization of different laser processes requires control over heating/cooling rate and thermal gradient. Different processes have different requirements of heating/cooling rate and thermal gradient. Knowing these parameters and relevant metallurgical information, one can predict the microstructure and hence control the material properties. To date, majority of laser processing is carried out by using either circular or rectangular beam. At present, the variation in temperature distribution to control the heating/cooling rates and thermal gradients is caused by the variation either in laser power or in scanning speed. Variations in these parameters are often limited by other processing conditions. Although different beam intensity distributions with circular or rectangular laser beams have been studied to improve the process, no other beam geometries have been investigated. The effect of laser beam geometry on laser processing of materials has received very little attention. This article presents an investigation of the effects of different beam geometries including circular, rectangular, and triangular shapes on heating of metallic materials. Finite-element modelling technique has been used to simulate the transient effects of a moving beam for laser surface heating of metals. The temperature distributions, cooling rates, and thermal gradients have been calculated. Some of the results have been compared with the experimental data.
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Ijiri, Masataka, and Toshihiko Yoshimura. "Surface modification of Cr‒Mo steel by new technology using high speed jet in water under ultrasonic irradiation." MATEC Web of Conferences 207 (2018): 03023. http://dx.doi.org/10.1051/matecconf/201820703023.
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In this study, to further improve current multifunction cavitation (MFC) techniques, the surface modification of Cr‒Mo steel was further investigated using 1200 W ultrasonic power. In MFC using 1200 W ultrasonic power, the corrosion resistance, and compressive residual stress of the specimens were improved when the processing time was 10 min; however, decarburization occurred at longer processing times, causing these characteristics to worsen. The decarburization that occurs at high ultrasonic outputs may be caused by an increase in the water temperature, and of the heating of the specimen surface.
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Lee, Kwang Seok, Won Kyu Bang, Tae Kwon Ha, Sang Ho Ahn, and Young Won Chang. "The Effect of Heating Rate on the Formability of Bulk Metallic Glass in a Supercooled Liquid Region." Key Engineering Materials 340-341 (June 2007): 59–64. http://dx.doi.org/10.4028/www.scientific.net/kem.340-341.59.
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The formability of a Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass has been investigated in the present study in relation to the heating rate. A series of extrusion tests after rapid heating has been performed in a laboratory scale together with sheet forming tests after slow heating for comparison purpose. The basic processing map based on dynamic materials model (DMM) and compression test data has been utilized to evaluate feasible forming conditions. The macroscopic formability, classified by fully formed, partially formed or a catastrophic fracture, is found to have a good correspondence with the iso-efficiency contour in the processing map. The region of high power dissipation efficiencies with η>0.8 is found to be broaden by avoiding crystallization events due to reduced exposure time in extrusion process with a faster heating rate.