Search Results (21)

In today’s data-driven age, the thermal properties of computer transistors play an important role. In this research, finite element simulation is employed to construct the structural model of the primary components within a computer chassis, and the thermal performance is evaluated based on ambient temperature, thermal conductivity, and heat dissipation rate. By combining the particle swarm optimization algorithm with numerical simulation for joint simulation and structural optimization, the component layout was optimized to reduce the working temperature. The results show that when the background temperature, that is, the ambient temperature, rises from −20 °C to 60 °C, the maximum operating temperature of the computer is approximately 88 °C. The maximum temperature is mainly in the transistor core and the minimum temperature is in the intake grille, and the operating temperature of the optimized structure decreases by approximately 10 °C. The research shows that the operating temperature is most sensitive to the change of background temperature, and the transistor core is the main heating source. The maximum temperature can be reduced by rationally adjusting the position of the components. This study provides a reference for analyzing the thermal performance of computers and optimizing structures. Full article

The growing concern over the presence of polycyclic aromatic hydrocarbons (PAHs) in grilled meats has intensified the search for natural mitigation strategies. This study evaluates the effect of red grape pomace (RGP), a natural by-product with antioxidant properties, on the lipid stability, color, fatty acid profile, volatile compounds, and PAHs formation in barbecued pork burgers. Unlike previous studies focusing on polyphenol extracts, this work investigates, for the first time, the direct incorporation of whole RGP stabilized by high hydrostatic pressure (HHP), a method that preserves its bioactive profile and ensures food safety. Incorporation of RGP at different levels (0.5%, 1%, and 3%) demonstrates its potential as a functional ingredient in meat products. Our results show that RGP effectively inhibits lipid oxidation, as indicated by significantly lower malondialdehyde (MDA) levels (p < 0.001) compared to control batches. It also modified the fatty acid profile by reducing saturated fatty acids and increasing the linoleic acid content (up to 15.56% at the 3% level). As the RPG concentration increased, color parameters (lightness, redness, yellowness, chroma, and hue) decreased significantly (p < 0.001), particularly at higher pomace levels (1% and 3%). The RGP did not significantly affect the PAH concentration, indicating its safe use in barbecued products. However, it selectively influenced volatile compounds, decreasing the hydrocarbon levels at higher concentrations, likely due to its antioxidant properties. These findings suggest that stabilized RGP may serve as a natural additive that enhances the nutritional quality and reduces lipid oxidation, without promoting PAH formation in thermally processed meats. Full article

The development of plant-based seafood alternatives with authentic flavour profiles remains a significant challenge, limiting their appeal to seafood consumers. This study hypothesised that incorporation of flavour precursors including free amino acids, betaine, and long chain omega-3 fatty acids would enhance the flavour resemblance of plant-based prawn and salmon prototypes to their authentic seafood counterparts. Prototypes were analysed using headspace solid-phase microextraction gas chromatography–mass spectrometry and evaluated by a semi-trained sensory panel. Volatile analysis revealed 64 compounds across prototypes, with significant variations attributed to precursor combinations and thermal treatments. Frying enhanced volatile profiles, particularly in plant-based prawn prototypes fortified with all three flavour precursors, producing key prawn odourants, including pyrazines and trimethylamine. Notably, betaine pyrolysis under moderate cooking conditions was demonstrated as a potential pathway for trimethylamine formation, contributing to fish-like odours. Sensory evaluation showed that the final plant-based prawn prototype exhibited strong cooked crustacean and grilled notes, aligning with the observed volatile profile. While the salmon prototype displayed key salmon odourants, its cooked salmon odour was less pronounced, suggesting a need for a more robust flavouring strategy. This study highlights the potential of targeted flavour precursor formulations to improve the flavour quality of plant-based seafood alternatives, paving the way for their wider acceptance. Full article

Grilling has become a widespread method of thermal food processing. However, food prepared in this way may be a source of carcinogenic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs). The present study aimed to evaluate the impact of different marinades and grilling tools on PAH contamination of chicken breast tenderloins. Together with the determination of PAHs carried out using the QuEChERS–HPLC–FLD/DAD method, the meat’s weight loss after the thermal process and the color of raw and grilled samples were analyzed. Statistically, the highest levels of PAH contamination were found in samples prepared on a charcoal grill without a tray, whereas the lowest were seen using the ceramic contact grill. Meat marination showed that universal and chicken marinades can be barriers against PAHs. Following requirements set in Commission Regulation (EU) No. 915/2023, none of the analyzed samples exceeded the maximum allowable level for B[a]P (5.0 µg/kg) and the sum of four marker-heavy PAHs (30.0 µg/kg). Thus, preparing meat before the thermal process, including marinades rich in phenolic compounds, and selecting a grilling method with appropriate grilling tools can ensure food safety and effectively reduce PAH contamination in grilled poultry meat. Full article

Changing eating habits and an increase in consumption of thermally processed products have increased the risk of the harmful impact of chemical substances in food on consumer health. A 2002 report by the Swedish National Food Administration and scientists at Stockholm University on the formation of acrylamide in food products during frying, baking and grilling contributed to an increase in scientific interest in the subject. Acrylamide is a product of Maillard’s reaction, which is a non-enzymatic chemical reaction between reducing sugars and amino acids that takes place during thermal processing. The research conducted over the past 20 years has shown that consumption of acrylamide-containing products leads to disorders in human and animal organisms. The gastrointestinal tract is a complex regulatory system that determines the transport, grinding, and mixing of food, secretion of digestive juices, blood flow, growth and differentiation of tissues, and their protection. As the main route of acrylamide absorption from food, it is directly exposed to the harmful effects of acrylamide and its metabolite—glycidamide. Despite numerous studies on the effect of acrylamide on the digestive tract, no comprehensive analysis of the impact of this compound on the morphology, innervation, and secretory functions of the digestive system has been made so far. Acrylamide present in food products modifies the intestine morphology and the activity of intestinal enzymes, disrupts enteric nervous system function, affects the gut microbiome, and increases apoptosis, leading to gastrointestinal tract dysfunction. It has also been demonstrated that it interacts with other substances in food in the intestines, which increases its toxicity. This paper summarises the current knowledge of the impact of acrylamide on the gastrointestinal tract, including the enteric nervous system, and refers to strategies aimed at reducing its toxic effect. Full article

Among the foods frequently consumed by consumers is meat. Among other things, it contains selenium, and the content depends on the amount of consumption of this element by animals, which requires monitoring as a metalloid. The purpose of this study was to: examine the impact of various types of heat processing used by consumers (water bath cooking WBC, oven convection roasting OCR, grilling G, pan frying PF) on the selenium content and its retention in goose breast meat (with and without skin) and estimate the coverage of this element’s daily requirement in adults after consuming 100 g of goose breast meat with skin or without skin. The material used in the study comprised 36 breast muscles cut from carcasses of 17-week-old White Koluda geese. The moisture, ash, and selenium were determined in both raw and thermally processed muscles. It has been concluded that various methods of heat processing significantly impact the cooking loss, moisture, ash and selenium content of meat, but not the selenium retention. The heat processing increased the selenium content of the muscle regardless of the presence of skin, which affects the possibility of covering adults’ Nutrient Reference Values-Requirements (NRV-R) for this element in the range of 33.3–44.8%. Goose breast meat can be a valuable component of a diversified diet. It is also a safe source of selenium. It is unlikely that adult consumers, even those who eat goose regularly, will exceed this element’s upper tolerable intake level. For selenium retention and NRV-R coverage, consumers would benefit most from goose breast meat with or without skin undergoing OCR or G treatment. Full article

(1) Background: With the rapid development of cloud computing, large AI models, and other emerging technologies, the issue of heat dissipation in data centers has become increasingly prominent. This issue is often caused by inappropriate temperature distribution when using cold air to cool servers. Improving temperature distribution is key to optimizing the thermal performance of data centers. Previous solutions do not include installing adjustable underfloor deflectors under a raised floor while adjusting the aperture ratio of the floor grille and replacing the side of the floor grille located near the air-conditioning unit with a fan floor. (2) Methods: A 3D model of a data center was established, and its meshing and boundary conditions were set. The airflow inside the data center was analyzed using a CFD simulation to assess the temperature distribution resulting from two proposed solutions. (3) Results: Simulations and analyses showed that both options balanced the airflow close to and away from the conditioned side cabinets. This maximized the cooling capacity and improved temperature uniformity. The maximum temperature drop registered for the average cabinet’s out temperature was 2.81 °C. And by installing an adjustable underfloor deflector under the floor grille in rows O and N and adjusting the grille opening, the airflow to the cabinet near the air-conditioned side increased by 18.1%, and the airflow away from the air-conditioned side decreased by 5.1%. Similarly, replacing the Q-row floor grille with a fan floor resulted in a 4.9% increase in airflow to the cabinet near the air-conditioning side and a 3.8% decrease in airflow to the cabinet away from the air-conditioning side. (4) Conclusions: Airflow is a crucial factor that affects cabinet temperature. And balancing airflow between the front-end and rear-end cabinets is essential to make the best use of the cooling capacity and improve temperature distribution within data-center cabinets. This can be achieved by installing a fan floor and an underfloor deflector device in front of high-temperature cabinets located near air-conditioning units. Full article

Bell peppers (Capsicum annuum L.) in various stages of maturity are widely used in the diets of individuals and in the food industry; they are consumed both fresh and after thermal processing. However, every type of processing impacts the overall textural and bioactive characteristics of this plant-based food. In order to quantify the changes in the bioactive substances and color-structural characteristics that occur during selected heat treatments (contact grilling, roasting, roasting combined with microwaving, and steam cooking) of bell peppers at three maturity stages (green, yellow, and red), analyses of antioxidant activity, reducing sugar content, polyphenolic compound content, textural properties, and color coordinates in the L*a*b* system were carried out. Some of the processes used, such as contact grilling (15.43 mg GAE/g d.b.) and roasting combined with microwaving (15.24 mg GAE/g d.b.), proved to be beneficial as the total polyphenol content of green peppers (2.75 mg GAE/g d.b.) increased. The roasting (3.49 mg TE/g d.b.) and steaming (6.45 mg TE/g d.b.) methods decreased the antioxidant activity of yellow bell peppers (14.29 mg TE/g d.b.). Meanwhile, the roasting (0.88 mg Glc/g d.b.), contact-grilling (2.19 mg Glc/g d.b.), simultaneous microwaving and roasting (0.66 mg Glc/g d.b.), and steaming (1.30 mg Glc/g d.b.) methods significantly reduced the content of reducing sugars and reducing substances in red bell peppers (4.41 mg Glc/g d.b.). The studies proved that in order to preserve the antioxidant and bioactive properties of bell peppers, it is necessary to consider the use of appropriately selected heat treatments, depending on the different stages of maturity. The proper selection of adequate thermal treatment can not only increase digestibility, but also improve the bioavailability of bioactive substances from this raw material. Full article

Manganese is a trace element with essential physiological functions that should be supplied to animals and humans through diet. Goose meat is prevalent in many regions of the world. Therefore, the aim of the study was a systematic review (PRISMA statement, 1980–2022) of the content of Mn in raw and cooked goose meat and their relation to the recommended intake at the level of adequate intake (AI) and the nutrient reference values-requirements (NRV-R). The literature analysis shows that the content of Mn in goose meat depends on the breed, type of muscles, the presence of skin, and the cooking method used. AI level recommendations for Mn intake range from 0.003 to 5.50 mg/day, depending on the country, age, and gender. Consumption by adults (regardless of sex) of 100 g of domestic or wild goose meat covers the daily AI per Mn in various percentages, depending on the type of muscles (more Mn in leg muscles), presence of skin (more Mn in skinless muscles), and thermal treatment (pan fried with oil, grilled, and cooked meat contains more). Placing information on the Mn content in goose meat and the percentage of NRV-R on the packaging may be valuable information for the consumer in making food choices to diversify the diet. There are few studies on the content of Mn in goose meat. Therefore, it is reasonable to conduct research in this area. Full article

The thermal grill illusion induces a pain sensation under a spatial display of warmth and coolness of approximately 40 °C; and 20 °C. To realize virtual pain display more universally during the virtual reality experience, we proposed a spatiotemporal control method to realize a variable thermal grill illusion and evaluated the effect of the method. First, we examined whether there was a change in the period until pain occurred due to the spatial temperature distribution of pre-warming and pre-cooling and verified whether the period until pain occurred became shorter as the temperature difference between pre-warming and pre-cooling increased. Next, we examined the effect of the number of grids on the illusion and verified the following facts. In terms of the pain area, the larger the thermal area, the larger the pain area. In terms of the magnitude of the pain, the larger the thermal area, the greater the magnitude of the sensation of pain. Full article

The causes of the fracturing of stone grills in barbecue ovens were analyzed using a coupled analysis model that combined combustion thermodynamics with heat conduction and the finite element method. The proportion of mixed air for combustion was simulated, and the stone grill plate temperature and thermal stress distribution were the two factors taken to enhance the design of stone grill plates. Moreover, thermal images were used to compare the performance of the original and the improved plates to quantify the improvements, and validate the accuracy of the simulations. The results showed that the temperature distribution was uniform across the stone grill plate. When comparing the simulation model and the actual experiment, the simulation model can generate an optimal design with fewer errors in a shorter period. The combustion tube is deemed to have considerable influence on the performance of the barbecue oven. The surface temperature distribution of the stone grill plate was improved by controlling the amount of fuel entering the combustion system and/or changing the material and shape of the stone grill. On the other hand, the analysis results of the improved stone grill plate in this study showed that we can correct the temperature difference and thermal stress difference caused by the opening of the upper cover of the oven. According to our study, the average thermal stress on the surface of the stone grill plate was effectively reduced by 45.3 MPa. The average temperature difference decreased by 91 °C. At the same time, by improving the intake position and method of the combustion tube, the air mass flow in the combustion tube increased by 12%, which effectively improved the combustion efficiency of the combustion tube. In particular, a more uniform distribution was achieved by decreasing the temperature of the mixed air entering the combustion tube, which in turn increased the flow rate and velocity of the air flowing through the top of the flame to the bottom surface of the stone grill plate. The strategies employed can prevent the thermal-stress-induced fracturing of stone grill plates and prolong their service life. Full article

In order to ensure the full heat dissipation of heat exchangers, the opening of the grille should be large, which increases the wind drag of the whole vehicle. Most of the research on the grille only focuses on its impact on the heat dissipation of the engine compartment; there is little research on its influence on the performance of the thermal management system, because it is difficult to solve the real-time data interaction of different dimensional models. So we established the 1D and 3D strong coupling model. The biggest difference from other 1D and 3D coupling models is that we can use the interfaces reserved by the two kinds of software to realize real-time data interaction, and simultaneously analyze the 1D thermal management performance and 3D flow field and temperature field of the engine components. The coupling model is used to study three heat balance conditions. The results show that the heat-sinking capability of the cooling system is the worst under the climbing condition; and the refrigeration capacity of the air-conditioning system is the worst under the idling condition. According to the heat balance results and evaluation index priorities, we determine the simulation process. In this article, first the upper grille is gradually closed; then the flow field, temperature field and evaluation indexes are studied through the strong coupling model to obtain the analysis results of the upper grille; then based on the results, the lower grille is gradually closed, and the analysis results of the lower grille are obtained in the same way. The final simulation results show that on the premise of ensuring the performances of engine cooling system and air conditioning refrigeration system, the air drag coefficient is reduced by 17.5 counts compared with the original vehicle. Full article

One main challenge of air distribution in classrooms is to guarantee ventilation performance under different usage conditions. In this study, the indoor climate in summer and winter conditions with different occupancy densities in the classroom is presented. Thermal condition measurements of a half-size classroom were performed in a test room with four air suppliers: wall-grilles, ceiling diffusers, perforated duct diffusers, and displacement ventilation. Those measured data were used for CFD validation of the whole classroom. With CFD simulations, indoor climate parameters with different air diffusers are compared in summer and winter conditions. The results show that displacement ventilation gives the best performance in the occupied zone. The air change efficiency can be reached with displacement ventilation of 1.4 and of only 1 with the other three air diffusers. The air velocities were reasonably low (<0.3 m/s), and the indoor was quite uniform with ceiling diffusers, which is another well-performing solution for classrooms. Corridor wall-grilles give uniform thermal conditions but can have high velocities (0.4 m/s) on the perimeter side of the room space. The air distribution from the perforated duct diffuser is unstable, which causes high local draft (over 20%) in the occupied zone. Full article

Battery electric vehicles (BEVs) are currently enjoying rising sales figures. However, BEVs still have problems with customer acceptance, partly due to limited driving ranges. To improve the situation, this paper introduces a novel approach utilising temperature-dependent efficiencies using an economic model predictive control approach (MPC) in combination with an active grille shutter in order to accelerate the heating of the permanent magnet synchronous machine. The measurements of temperature-dependent component efficiencies on a powertrain test bench are presented and analysed in detail in the speed/torque range. Thermal models based on the lumped parameter thermal network approach were developed and validated as part of the system-level validation against a US06 wind tunnel measurement. After the build-up and implementation of the MPC, various simulations were conducted. For the investigations, three driving cycles were considered at component start temperatures of 20–80 °C. The results show that using the MPC with the grille shutter can save 0.69–2.02% energy at the HV level compared to the rule-based control with a shutter, of which up to 1.02% is due to temperature-dependent efficiencies. Comparing the MPC with the grille shutter to a vehicle without a shutter, savings of 2.8–4.2% were achieved, while up to 1.67% was achieved due to temperature effects in the powertrain. Full article

A variable refrigerant flow integrated stratum ventilation (VRF-SV) system was proposed as an energy efficient substitute for conventional central cooling systems for buildings. The novel system provided conditioned air to enclosed spaces with high indoor air quality and thermal comfort. This study investigated the effects of different types of ASTDs on the performance of the VRF-SV hybrid system. The performance was experimentally evaluated with five air terminal types, including bar grille, double deflection grille, jet slot, perforated and drum louver diffusers. The evaluation was carried out using standard indices: temperature and velocity distribution, airflow pattern, effective draft temperature (EDT), air distribution performance index (ADPI), thermal sensation vote and comfort feedback survey. The results indicated that the ASTD type had a significant impact on airflow pattern. Furthermore, the bar grille diffuser provided the occupants with greater thermal comfort and acceptable indoor environment. Almost all the EDT values determined in the breathing zone in the case with bar grille diffuser found under the satisfactory range, i.e., −1.2 < K < 1.2. Based on these values, the ADPI for bar grille diffuser was calculated as 92.8%. Thus, the bar grille diffuser is recommended to be installed with the VRF-SV hybrid system in buildings. Full article