Effect Of Radiant Heat Research Articles

The Effect of Radiant Heat on Polystyrene Thermal Insulation Materials

As a result of the increasingly stringent energy requirements of recent years, the issue of façade thermal insulation is gaining more and more prominence. Due to these requirements, layer thickness of insulation increases, or the use of materials with a better coefficient of thermal conductivity is preferred. These requirements are met by polystyrene insulation materials. Therefore, it is extremely important to know as much as possible the behaviour of polystyrene thermal insulation under the influence of fire and radiant heat. Its regulation is not coordinated in Europe, and the effect of radiant heat is not addressed by any country’s standard. In this paper, the behaviour of polystyrene thermal insulations, which are densely used in Hungary is examined, under the influence of radiant heat.

CFD analysis of air flows and temperatures based on radiant heating in industrial environments

Objective. The study aims to investigate the complex interaction between radiant heating and airflow in industrial environments.The aim is to understand the dynamics of temperature, with particular attention to optimizing energy efficiency and comfort in industrial premises heated by a dual-zone dark gas radiant heater. Method. Using Computational Fluid Dynamics (CFD) and Ansis simulation software, the study developed a model that represents typical industrial conditions. This method included the determination and verification of temperature gradients and air velocity parameters, as well as careful mapping of the complexities of the industrial heating process. Result. The analysis provides detailed graphical representations of temperature and air velocity at individual points, revealing the effect of radiant heating on airflow patterns. Particular attention has been paid to how the temperature profiles interact with a dual-zone heating system, revealing important data that helps understand thermal dynamics in industrial environments. Conclusion. The findings demonstrate the potential for significant progress in energy savings and improved worker comfort in industrial environments using radiant heating. The integrated research approach fills a critical gap in existing research, highlighting the need and potential for further exploration of sustainable heating technologies in challenging industrial environments.

Effect of radiant heat on straw

Effect of radiant heat on straw

Fire Risk Analysis of Petrochemical Plant Facilities through Fire Modeling

In this study, fire case analysis and fire type and risk analysis were conducted for each process according to the ISO 17776 checklist to determine the firefighting activities and worker evacuation areas in case of a fire in a petrochemical plant. Therefore, fire modeling was performed for storage tanks with the largest fire load according to the wind speed and combustibles in order to analyze the radiant heat and smoke behavior. The effects of radiant heat and smoke were increasingly high in the order of n-heptane, gasoline, and diesel. Moreover, the firefighting activities and worker evacuation areas varied greatly depending on the wind speed rather than combustibles. However, because the results of the study cannot exclude the possible dependence on the fire modeling, it is necessary to generalize and standardize the results of the study by accumulating data through various scenarios.

Effect of radiant heat induced by a diode laser (445nm) on setting process of glass-ionomer cements monitored by Fourier transform infrared spectroscopy.

The aim of this study was to investigate the effect of thermal energy induced by a diode laser (445nm) on the setting reactions of conventional glass ionomer cements (GICs) by using Fourier transform infrared spectroscopy (FTIR) and to compare it with that induced by a LED device. Four GICs were investigated in this study (GlassIonomer FX Ultra, Ketac Universal Aplicap, Equia Fill, and Riva Self Cure). The experimental groups of the study were as follows (n=5): Group 1 (control) - the specimens after mixing were left to set without any treatment; Group 2 - the specimens were irradiated for 60s using a LED (Valo™) at 1400mW/cm2 (fluence ∼ 1.4J/cm2); Group 3 - the specimens were also irradiated for 60s using a diode laser (SIROLaser Blue), which emits at 445±5nm with average output power of 0.7W (fluence ∼ 1.4J/cm2). FTIR analysis of the GIC specimens was followed to assess the changes in the COO-/CO ratios of the setting reaction and its progress in time. Both laser and LED treatments improved the setting reactions of the GICs compared to the control group (p<0.05). However, this phenomenon was not observed in all materials implying that it may be material dependent. Radiant heat treatments using diode laser or LED may be beneficial for the rate and progress of setting reaction of the conventional GICs. The composition and handling of the materials may be crucial for their final properties and the overall clinical behavior.

Combined Effect of Radiant Heat, Local Nusselt Number and Skin Friction Coefficient of a Third Grade Fluid through a Channel Flow in a Saturated Porous Medium

This paper investigates the combined effects of radiant heat, local Nusselt number and Skin friction coefficient on a channel flow of third grade fluid in the presence of saturated porous medium. It is assumed that the fluid has temperature-dependent variable viscosity and thermal conductivity. The non-linear governing differential equations are obtained and tackled numerically using Spectral element technique and C++ programming language. Increase in the values of radiation parameter and third grade material parameter consequently increase the local Nusselt number and skin friction coefficient. Graphical results showing the effects of various physical parameters are presented and discussed quantitatively. It is concluded that Williamson’s fluid parameter served as a cooling factor in diverse improved technological processes in order to avoid different machines from overheating and enhance their efficiencies.

Experimental Study of the Influence of Selected Factors on the Particle Board Ignition by Radiant Heat Flux.

Particleboards are used in the manufacturing of furniture and are often part of the interior of buildings. In the event of a fire, particleboards are a substantial part of the fuel in many building fires. The aim of the article is to monitor the effect of radiant heat on the surface of particle board according to the modified procedure ISO 5657: 1997. The significance of the influence of heat flux density and particle board properties on its thermal resistance (time to ignition) was monitored. Experimental samples were used particle board without surface treatment, with thicknesses of 12, 15, and 18 mm. The samples were exposed to a heat flux from 40 to 50 kW·m−2. The experimental results are the initiation characteristics such as of the ignition temperature and the weight loss. The determined factors influencing the time to ignition and weight loss were the thickness and density of the plate material, the density of the radiant heat flux and the distance of the particle board from the radiant source (20, 40, and 60 mm). The obtained results show a significant dependence of the time to ignition on the thickness of the sample and on the heat flux density. The weight loss is significantly dependent on the thickness of the particle board. Monitoring the influence of time to ignition from sample distance confirmed a statistically significant dependence. As the distance of the sample from the source increased, the time to ignition decreased linearly. As the distance of the sample from the source increased, the time to ignition increased.

Fire Spread Risk Assessment Process for Radiant Heat Flux of Flame Ejected from Opening in Fire

When a flashover occurs from a fire in a building compartment, the fire intensifies explosively and changes from a fuel-controlled fire to a ventilation-controlled fire. As a result, flames and unburnt gas are ejected from openings. The ejected unburned gas reacts violently with external oxygen to form a large-scale ejected flame, which causes the fire to expand to the upper layer. Moreover, the radiation of extreme heat to neighboring buildings contributes to fire spreading between buildings. In this study, a quantitative evaluation process was established to evaluate the thermal effect of radiant heat generated from an open fire on the exterior materials of facilities, assuming a fully developed fire.

Amaranthus retroflexus L. (Redroot Pigweed): Effects of Elevated CO2 and Soil Moisture on Growth and Biomass and the Effect of Radiant Heat on Seed Germination

Amaranthus retroflexus L. (Amaranthaceae), Redroot pigweed, is native to North America, but has become a weed of agriculture worldwide. Previous research into competition with food crops found it significantly reduces yields. Additionally, taxonomy, biomass allocation, physiological responses to light intensity, water stress, elevated CO2, and herbicide resistance have been investigated. To extend other research findings, we investigated growth and biomass yield in response to (i) soil moisture stress, and (ii) drought and elevated CO2. Additionally, we investigated seed germination rates following exposure to three elevated temperatures for two different time periods. Overall, moisture stress reduced plant height, stem diameter, and number of leaves. Elevated CO2 (700 ppm) appeared to reduce negative impacts of drought on biomass productivity. Heating seeds at 120 °C and above for either 180 or 300 s significantly reduced germination rate. These results inform an understanding of potential responses of A. retroflexus to future climate change and will be used to predict future occurrence of this weed. The finding that exposing seeds to high temperatures retards germination suggests fire could be used to prevent seed germination from soil seed banks, particularly in no-till situations, and therefore may be used to address infestations or prevent further spread of this weed.

Effects of Radiant Heat and Frictional Abrasion on Thermal Protective Performance of Clothing Against High Pressurized Steam

This study focused on changes in protective performance of steam protective clothing after exposure to conditions such as thermal radiation and frictional abrasion. Totally eight radiation conditions varying on exposure duration and times, four types of abrasion scenarios with different friction cycles and three different combined treatments were designed. Results demonstrated that any increase in radiant exposure duration or exposure times would lead to an initial increase and then a following decrease in the steam protective performance. However, the steam protective performance seemed relatively immune to the friction cycles. When thermal radiation and frictional abrasion acted together, interactions between them existed and their specific interaction highly depended on the distribution of heat exposure duration and friction cycles. Findings of this study provided insight into factors influencing steam protective performance, and could be an aid in developing high performance materials or guidelines for use and maintenance of protective clothing.

Effect of Local Radiant Heating on Thermal Comfort in Cold Environment

In cold environment, local radiant heating can improve thermal comfort. In this paper, the local radiant heating equipment was used to heat subjects’ ankles and backs separately at an ambient temperature of 12.5°C and 14.5°C, with the radiant power of 200W, 300W and 500W. The number of subjects was 20.The subjects’ thermal comfort changes were collected through a subjective questionnaire. The results show that local radiant heating can improve human thermal comfort. The effect of radiant heat source located on the back of human body is better than that on ankle. Local radiant heating in cold environment has energy saving effect.

Study on the Evaluation of Radiant Heat Effects of Oil Storage Tank Fires Due to Environmental Conditions

In this paper, the risk of damages to humans and properties due to fire explosions in gasoline storage tanks is identified, and the effects of radiant heat on adjacent tanks are evaluated to present the necessary area to secure safety. A simulation was conducted to evaluate the effect of radiant heat (Maximum emission) on adjacent tanks in an oil storage tank fire due to environmental conditions (Wind speed and temperature) in the Northern Gyeonggi Province. The result indicated that the radiant heat released in the fire of an oil storage tank was increased by approximately 1.9 times by the maximum wind speed and the difference occurred in the range of 700~800 kW by the maximum temperature. If a storage tank fire occurs, securing approximately 34.4 m of holding area is necessary. In the future, evaluating the radiant heat emitted by the fire of gasoline storage tanks will be required by applying various environmental conditions, and through this, research on specific and quantitative holding area is required.

Growth of plasma-enhanced chemical vapour deposition and hot filament plasma-enhanced chemical vapour deposition transfer-free graphene using a nickel catalyst

This paper investigates the effects of radiant heat from implementing a hot filament (HF) in an existing Plasma-enhanced Chemical Vapour Deposition (PECVD) system on the growth of transfer-free graphene. The fabrication and properties of the transfer-free graphene grown using the HF-PECVD technique with nickel (Ni) as a catalyst were compared to that of transfer-free graphene grown using the existing PECVD method. The Ni film was used as a catalyst to assist the formation of graphene at the Ni-substrate interface for both techniques. Instead of undergoing an additional Ni annealing process, an increase in deposition temperature was achieved from the radiant heat of the hot filament in the HF-PECVD, changing the Ni grain size from nano-sized to micro-sized and reducing the formation of Ni grain boundaries. The increase in Ni grain size and the reduction in the grain boundary formation promoted the formation of less defective graphene with a more ordered structure. The formation of well-ordered graphitic-structured graphene also corresponded to the disappearance of O contamination in the Ni catalyst due to the higher deposition temperature. The enhancement in the structure, morphology, and chemical bonding of the transfer-free graphene grown using the HF-PECVD technique resulted in improved electrical properties of the film.

Effect of perspired moisture and material properties on evaporative cooling and thermal protection of the clothed human body exposed to radiant heat

Perspired moisture plays a crucial role in the thermal physiology and protection of the human body wearing thermal protective clothing. Until now, the role of continuous sweating on heat transfer, when simultaneously considering internal and external heat sources, has not been well-investigated. To bridge this gap, a sweating torso manikin with 12 thermal protective fabric systems and a radiant heat panel were applied to mimic firefighting. The results demonstrated how the effect of radiant heat on heat dissipation interacted with amount of perspired moisture and material properties. A dual effect of perspired moisture was demonstrated. For hydrophilic materials, sweating induced evaporative cooling but also increased radiant heat gain. For hydrophilic station uniforms, the increment of radiant heat gain due to perspired moisture was about 11% of the increase of heat dissipation. On the other hand, perspired moisture can increase evaporative cooling and decrease radiant heat gain for hydrophobic materials. In addition to fabric thermal resistance ( Rct) and evaporative resistance ( Ret), material hydrophilicity and hydrophobicity, emissivity and thickness are important when assessing metabolic heat dissipation and radiant heat gain with profuse sweating under radiant heat. The results provide experimental evidence that Rct and Ret, the general indicators of the clothing thermo-physiological effect, have limitations in characterizing thermal comfort and heat strain during active liquid sweating in radiant heat. This paper offers a more complete insight into clothing thermal characteristics and human thermal behaviors under radiant heat, contributing to the accurate evaluation of thermal stress for occupational and general individuals.

Aspirated and non‐aspirated automatic weather station Stevenson screen intercomparison

In this study six wooden Stevenson screen configurations (five aspirated, one non‐aspirated) were evaluated at the Centre for Atmospheric Research Experiments in Egbert, Ontario, Canada. The field experiment was performed over a 1‐year period to evaluate aspirated and non‐aspirated Stevenson screen configurations used at the Meteorological Service of Canada’s Automated Weather Stations. The results show the non‐aspirated screen is warmer than the aspirated screen duct location by 0.11 °C on average with a significant increase in the maximum daily temperature of 0.22 °C due to radiant heating effects. Temperature differences up to 2.1 °C were observed between the aspirated and non‐aspirated screens with a mean increase of 0.46 °C following 30‐min periods of mean global radiation greater than 200 W/m2 and mean wind speed less than 2 m/s. Temperature differences between the two screens are more variable with standard deviations up to 0.3 °C for wind speeds below 2 m/s. The maximum daily temperature for the historic minimum and maximum thermometer locations and upper regions of the aspirated screen is also found to be significantly warmer during radiant heating conditions. The three locations within the aspiration duct provided very similar results with mean differences of −0.02 and −0.01 °C below the probe uncertainty. The aspirated Stevenson screen with motor off produced low overall bias with lower maximum daily temperatures and higher minimum daily temperatures compared to the aspirated screen. Comparison between the historic wooden frame and new aluminium mounting is not significant with the wooden frame cooler by 0.02 °C overall. Differences between the new aluminium and new plastic ducts showed similar results of 0.02 and 0.01 °C overall. The aspirated Stevenson screen configuration is recommended at new Automatic Weather Station installations where AC power is available.

Effect of Three Clinical Curing Treatments on Fluoride Release and Surface Hardness of Glass-Ionomer Cements.

The purpose of this study was to investigate the effect of radiant heat, ultrasonic treatment, and 42.7 wt% CaCl₂ solution on fluoride release and surface hardness in three conventional glass-ionomer cements (GICs). The fluoride release patterns of each GIC were evaluated during a 28-day period using a fluoride ion-selective electrode. The surface hardness of the tested GICs was evaluated 24 hours after preparation of the specimens using Vickers hardness test. Statistical analysis of the data was made using analysis of variance and Bonferroni post hoc test (α = .05). Radiant heat, ultrasonic, and CaCl₂ solution treatments reduced fluoride release and increased the surface hardness of the tested GICs (P < .05). Among the tested GICs, differences in fluoride release and surface hardness were observed (P < .05). The clinical treatments investigated may be effective methods for improving the setting reaction of GICs and may achieve sufficient initial mechanical properties earlier. Although a reduction in fluoride release occurs after the treatments, anticariogenic properties of the GICs may not be significantly affected.

Effect of radiant heat on conventional glass ionomer cements during setting by using a blue light diode laser system (445nm).

The aim of this in vitro study was to evaluate the effect of radiant heat on surface hardness of three conventional glass ionomer cements (GICs) by using a blue diode laser system (445nm) and a light-emitting diode (LED) unit. Additionally, the safety of the laser treatment was evaluated. Thirty disk-shaped specimens were prepared of each tested GIC (Equia Fil, Ketac Universal Aplicap and Riva Self Cure). The experimental groups (n = 10) of the study were as follows: group 1 was the control group of the study; in group 2, the specimens were irradiated for 60s at the top surface using a LED light-curing unit; and in group 3, the specimens were irradiated for 60s at the top surface using a blue light diode laser system (445nm). Statistical analysis was performed using one-way ANOVA and Tukey post-hoc tests at a level of significance of a = 0.05. Radiant heat treatments, with both laser and LED devices, increased surface hardness (p < 0.05) but in different extent. Blue diode laser treatment was seemed to be more effective compared to LED treatment. There were no alterations in surface morphology or chemical composition after laser treatment. The tested radiant heat treatment with a blue diode laser may be advantageous for the longevity of GIC restorations. The safety of the use of blue diode laser for this application was confirmed.

Effect of radiant heat and ultrasound on fluoride release and surface hardness of glass ionomer cements.

The purpose of this investigation was to evaluate the influence of radiant heat and ultrasound on fluoride release and surface hardness of 3 glass ionomer cements (GICs). There were 3 experimental groups for each GIC; in group 1, the specimens were left to set without any treatment; in group 2, the specimens were irradiated for 2 minutes using a LED unit; and in group 3, ultrasound was applied using a scaler for 55 seconds on the specimen surface. Fluoride release measurements were performed daily for 7 days and at days 14 and 28. Surface hardness of the tested GICs was determined using Vickers method. The measurements were performed 24 hours and 7 days after mixing. Statistical analysis of the data was made using 1-way ANOVA and Tukey's and Bonferroni post hoc tests (α = 0.05). Radiant heat during setting reduced the fluoride release and increased the surface hardness of GICs (p&lt;0.05). Ultrasonic treatment also reduced the fluoride release and increased the surface hardness (p&lt;0.05) of GICs but in lower extent. Among the GICs there were differences in fluoride release and surface hardness properties depending on their composition (p&lt;0.05). Radiant heat and ultrasonic treatments may be useful methods for GIC restorations in order to achieve faster adequate initial mechanical properties.

Effect of radiant heat at the birth site in farrowing crates on hypothermia and behaviour in neonatal piglets

It has been documented that floor heating of the farrowing area in loose housed sows improves survival of piglets significantly. However, today, the majority of farrowing pens are designed with crating of sows and slatted floor at the birth site. The aim of this study was to investigate whether providing radiant heat at the birth site to new-born piglets in pens with crated sows reduced hypothermia, time to first milk intake and growth of the piglets during the 1st week. Second parity Danish Landrace×Yorkshire sows (n=36) were randomly divided into two groups: Control (CG) and heat (HG). In the area behind the sow (zone 1), two radiant heat panels were mounted above the slatted floor in the HG. The farrowings were attended, and the heaters were turned on at birth of first piglet and turned off 12 h after. Birth time, time to leave zone 1, time to first contact with udder and time to first suckling were registered by direct observation. The piglet’s rectal temperature (RT) was measured 15, 30, 60, 120, 180, 240 min after birth and 12, 14 and 24 h after birth of first piglet. Piglets were weighed at birth, 24 and 48 h and 7 days after birth. Data were analysed in a mixed model in SAS. The drop in RT was lower in HG compared with CG (P=0.002), and the RT in HG remained higher than in CG from 30 to 240 min after birth (P<0.05), whereas no difference was found at 12 h after birth of first piglet (P=0.92). Piglets in HG stayed longer in zone 1 than those in CG (P=0.01), whereas time to reach udder (P=0.35) and to first suckling (P=0.56) did not differ. No difference in weight gain was found between piglets in HG and CG at 24 h (P=0.23), 48 h (P=0.28) and 7 days after birth (P=0.44). Birth weight had a positive effect on RT (P<0.001) and reduced time to leave zone 1 (P<0.01), reach udder (P<0.001) and time to first suckling (P<0.001). The results showed that radiant heating behind the sows reduced hypothermia in new-born piglets and indicate that providing heat during the first half hour after birth is important.

Atmospheric stability of surface boundary layer in coastal region of the Wol–Ryong site

In order to provide statistically reliable information of a wind energy site, accurate analysis on the atmospheric stability and climate characteristics in a certain area is a prerequisite. Two 2-D ultrasonic anemometers and one cup anemometer, located perpendicular to the prevailing wind direction, were used to measure the atmospheric wind environment at a height of 4.5 m in coastal region of the Wol–Ryong, Jeju, South Korea. The study is aiming to understand the atmospheric stability about a coastal region, and the effect of roughness length. We calculate the Monin–Obukhov length for division of atmospheric stability about unstable regime, neutral regime and stable regime. The distribution of diurnal Monin–Obukhov length is highly sporadic in the coastal region due to the effect of radiant heat from the surface or other environmental effects. In order to calculate the roughness length in coastal region, three different methods are applied in terms of the surface roughness, flow fluctuation and gust wind, which are called logarithmic profile, standard deviation and gust factor methods. In the study, the atmospheric stability was insignificant when applying these three methods. In the results, three different roughness length scales sufficiently showed the effect of obstacle and surface conditions around the measurement position. On the basis of an overall analysis of the short-term data measured in the Wol–Ryong area, Jeju Island, it is concluded that for the development of future wind energy resources, the Wol–Ryong site could be a good candidate for a future wind energy site.