Heating Chamber Research Articles

Five weeks of heat training increases haemoglobin mass in elite cyclists.

What is the central question of this study? Do haemoglobin mass and red blood cell volume increase in elite cyclists training in a hot environment compared to a control group training at normal temperature? What is the main finding and its importance? Fiveweeks of heat training increases haemoglobin mass in elite cyclists. There are small to intermediate effect sizes for exercise parameters favouring heat training. In this study we tested the hypothesis that performing 1h of regular light exercise in a heat chamber (HEAT; 37.8±0.5°C; 65.4±1.8% humidity) 5timesweek-1 for a total of 5weeks increases haemoglobin mass (Hbmass ) and exercise performance in elite cyclists ( =76.2±7.6mlmin-1 kg-1 ). Twenty-three male volunteers were assigned to HEAT (n=11) or CON (n=12; 15.5±0.1°C; 25.1±0.0% humidity) training groups. Hbmass was determined before and after the intervention period in conjunction with an extensive exercise test protocol (conducted at 16-19°C). HEAT increased (P<0.05) Hbmass by 42g from 893±78 to 935±108g whereas Hbmass remained unchanged (+6g) in CON. Furthermore, statistical analysis revealed a time-group interaction (P<0.05). The greater increase in Hbmass in HEAT, however, did not manifest in a greater increase in (225±274mlmin-1 in HEAT and 161±202mlmin-1 in CON). While HEAT reduced (P<0.05) lactate levels during some of the submaximal exercise tests, there was no statistical difference between other performance parameters. There were, however, small to intermediate effect sizes favouring HEAT for lactate threshold power output (2.8±3.9 vs. -0.4±5.1% change, effect size (ES)=0.34), gross economy in the fatigued state (0.19±0.42 vs. -0.12±0.49%-point change, ES=0.52) and 15min mean power (6.9±8.4vs. 3.4±5.1% increase, ES=0.22). This study demonstrates an increase in Hbmass and small to intermediate effect sizes on exercise variables in elite cyclists following a 5-week heat training intervention.

Effect Of Vented Helmets On Heat Stress During Wildland Firefighter Simulation

Uncompensable heat from wildland firefighter (WLFF) personal protective equipment decreases the physiological tolerance while exercising in the heat. Our previous work demonstrated that the WLFF helmet significantly increases both perceived and actual head heat. PURPOSE: This study compared heat accumulation under simulated working conditions while wearing standard non-vented WLFF helmets (H) versus a vented helmet (VH). METHODS: Ten male subjects with VO2max of 59.8 ± 3.6 ml·kg·-1min·-1 completed two trials. Following a 10-minute seated acclimation period, subjects walked 180 minutes (at 3.5 mph, 5% grade) in a heat chamber (35°C and 30% relative humidity) with three intervals of 50 minutes of exercise and 10 minutes rest followed by a work capacity test to exhaustion. Subjects randomly completed opposing helmet trials separated by a two-week washout. Each trial measured physiological strain index (PSI), visual analog scale (VAS), helmet temperature and relative humidity (Th, Rh), rating of perceived exertion (RPE) and heart rate (HR). Data was analyzed using a 2X6 repeated measures ANOVA. RESULTS: All subjects finished all trials. Work capacity was significantly greater in the VH trial (95.9±10.3 KJ H vs. 109.3±8.5 KJ VH, P=0.001). At the end of the 3 hour trial HR (146.8±17.2 bpm H, 144.3±17.9 bpm VH), PSI (6.08±1.45 H, 5.89±1.24 VH), RPE (14.2±1.7 H, 13.3±1.7 VH), Th (35.52±0.47°C H, 35.75±0.50°C VH), and Rh (45.6±5.1% H, 41.0±5.9% VH) showed a significant effect of time (p<0.05) but were not significant between trials. End trial PSI and HR significantly related to work performed (r=>-0.8, P<0.001). CONCLUSION: Elevated work, trends for RPE, helmet microenvironment, and VAS suggest greater heat dissipation and comfort with the vented helmet. This suggests the standard unvented WLFF helmet may contribute to accumulated heat over time, which may affect work output and safety in the field. Supported by the USFS (18-CR-11138100-005).

Heat transfer of nano powder inside a porous tank with use of non-equilibrium approach

In current numerical investigation, irreversibility and energy transportation related to free convection though a porous wavy chamber was scrutinized. One of the essential factors in design of unit is irreversibility which should be minimized. The inner wavy surface acts as heat element and chamber is filled with hybrid nanomaterial. New correlations, contours and profiles are main kinds of outputs which achieved by employing CVFEM. As Ra augments, the magnitude of ψmax enhances which indicates higher convective mode, and better cooling rate of inner wall happens. At lowest Ra and Nhs, Nu declines about 57.2% and Be augments about 2.75% with augmenting Lorentz force. Nu becomes 7.5 times greater with growth of Ra when other variables are minimum. Be reduces about 2.49% with rise of Nhs at Ra⁎ = 5, Ha = 20. Portion of thermal irreversibility augments with impose of stronger magnetic field. Growth of Ra leads to domination of convective mode and hence inner wall become colder. Reduction impact of Nhs on Nu become more stronger when buoyancy force augments. In comparison with Ra, Nhs has no sensible impact on Be.

UHF Device Introduction for Animal Raw Material Processing

The calculation of technical and economic indicators for a microwave implementation with a squirrel cage resonator at farms was carried out according to the standard method, taking into account the cost item: 1 The book value of the designed and manufactured microwave device (design model); 2 Operating costs for heat treatment of lumpy meat during the massaging in brine according to the design model; 3 The book value of the meat massager Gambit-120 (basic version); 4 Operating costs for lumpy meat massaging in a brine in vacuum and heat treatment in a separate heat chamber (basic version)

Properties of non-woven polylactic acid fibers prepared by the rotational jet spinning method

The preparation of non-woven polylactic acid (PLA) fibers was carried out by the rotational jet spinning method. The polymers were melted in a heat chamber and centrifuged with a high speed to obtain the fibers with the high productivity. The viscosity of polymers was an important factor for the quality and quantity of the non-woven fiber. In this work, a commercial grade and synthesized PLA were used to prepare the non-woven fiber. The non-woven PLA fibers were produced at different temperatures of 190–230 °C with rotational speed between 650 and 2800 rpm. The morphology of non-woven PLA was investigated by scanning electron microscopy. The effect of temperature was investigated by thermogravimetric analysis (TGA). The non-woven PLA had a smooth surface along the fibers. The result showed that as the temperature or rotational speed increased, the fiber diameter was decreased. The fiber diameters of PLA 3052D, L130, and synthesized PLA (at 650 rpm) decreased to 40%, 40%, and 24%, respectively, when increasing the temperature. The high temperature in the process led to generate the beads. The fiber diameter of PLA 3052D, L130, and synthesized PLA (at 190 °C) decreased to 66%, 23%, and 56%, respectively, with the higher rotational speed. Tonset of TGA showed that the thermal degradation of PLA fibers was reduced compared with PLA resin, but it was still considered to be insignificant after spinning. The wettability of the samples was determined by the mean of the water evaporation. The results showed that the weight of the water in the sample decreased rapidly compared with control cotton, indicating more hydrophobic nature of the fibers obtained at the high rotational speed and temperature.

Influence of heating intensity and size of gel fuel droplets on ignition characteristics

This experimental research studies the influence of heating intensity and typical initial size of particles (or droplets in molten state) on the main process parameter – ignition delay time – for a group of gel fuel compositions. The first group of fuels is based on oil-filled cryogels: the aqueous solution of polyvinyl alcohol (5 wt%) + 40–60 vol% of oil + 2 vol% of emulsifier. The second one was produced from identical oil-filled cryogels with fine solid combustible particles: the aqueous solution of polyvinyl alcohol (10 wt%) + 35 vol% of oil + 30% of coal (particle size 100 µm) + 2 vol% of emulsifier. Combustion was initiated in a chamber with a motionless air medium at 700–1,000°C, by introducing fuel particles into it at a rate of 0.04–0.10 m/s, their size varying from 2.5 to 3.1 mm. The consistent patterns and characteristics of processes during the induction period were recorded by a high-speed video camera and fast-response thermocouples. It has been established that the ignition delay times change in the range from 0.5 to 15 s, depending on the heating intensity (characterized by the air temperature in the chamber and the rate of introducing fuel particles into it) and component composition of the gel fuel. The calculated minimum density of the heat flux, required for the gel fuel ignition, is 40 kW/m2. At lower values, ignition does not occur even when the fuel is heated for more than 15 s, which is due to the complete evaporation of molten fuel components. The ignition delay times for all the fuel compositions and particles of different sizes differ by less than 10% (random error of measurement) at the heat flux density over 100 kW/m2. The factors under study affect the duration of the induction period only under the near-threshold (minimum) ignition conditions, when the air temperature in the chamber is 700–800°C. The higher the rates of introducing the fuel particles into the heating chamber (in the range of 0.04–0.10 m/s), the higher the oil concentration in the oil-filled cryogels (in the range of 40–60%), and the smaller the size of particles (ranging from 2.5 to 3.1 mm), the shorter the ignition delay times (by 30–40%, 25–35%, and 20–45%, respectively). At air temperatures above 900°C, the initial size of fuel particles does not have a significant effect on the ignition delay times (the difference in the recorded values does not exceed the random error of measurement).

Mathematical modeling of ohmic heating for inactivation of acid-adapted foodborne pathogens in tomato juice

Abstract The objective of the present study was to predict the inactivation trends of acid-adapted foodborne pathogens in tomato juice by ohmic heating through a numerical analysis method. The mathematical model based on finite element method (FEM) was used to simulate the multiphysics phenomena including electric heating, heat transfer, fluid dynamics, and pathogen inactivation. A cold spot was observed in the corner part of the ohmic heating chamber, where some pathogens survived even though all pathogens were inactivated elsewhere. Challenges of this study were how to reflect the increased resistance of pathogen by acid-adaptation. After simulation, we verified that inactivation level of acid-adapted foodborne pathogens by 25 Vrms/cm ohmic heating (1 kHz), predicted with the developed mathematical model, had no significant differences with experimental results (p &gt; 0.05). Therefore, the mathematical approaches described in the present study will help juice processors determine the processing conditions necessary to ensure microbial safety at the cold point of a rectangular type batch ohmic heater.

Thermo-magneto-hydrodynamical effects on merging flow of TiO2–water nanofluid

The steady flow of a nanofluid (mixture of titanium dioxide and water) in a rectangular channel under the influence of an inclined magnetic field is studied. The channel contains an upstream hot splitter plate in alignment with the upper and lower plates of the channel. It may be said that two incoming channel flows merge to form a single channel flow. This setup may apply to the heating chamber in which titanium dioxide can be used to enhance the thermal transfer rate. It is observed that the position of the splitter plate (that may act as an electric heater) affects the velocity and temperature of the fluid. Therefore, in order to ensure these facts, the examination of the flow behavior and the temperature distributions in the channel if the splitter is placed at different positions in the upstream have been probed. In addition, the effect of nanoparticles on the convection process has been probed. The streamlines are almost similar for a clear fluid as well as for a nanofluid (for low values of solid volume fraction of nanoparticles (i.e.$$\varphi < 0.05$$)) for all values of the Reynolds number. However, the rise in the temperature is noted for the nanofluid if the concentration of nanoparticles is increased. The increase in the Reynolds number also supports the enhancement of the Nusselt number and, hence, the thermal transfer rate of the nanofluid. The Nusselt number is dominant in the vicinity of the trailing edge of the splitter because the trailing edge exhibits as a stagnation point. In addition, the maximum Nusselt number for nanofluid at moderate Reynolds number (e.g., Re = 100) is enhanced to 0.3% with respect to the clear fluid. Moreover, obtained results for this particular case are compared with the existing literature, and the results compare well.

Renal hemodynamics and metabolism improve following a second Exertional Heat Stroke

Exertional Heat Stroke (EHS) occurs with rapid onset during strenuous exertion and results in hospitalization that is often associated with renal and hepatic injury. EHS may increase susceptibility to a subsequent EHS collapse if organ injury has not completely resolved prior to the second heat exposure. We investigated renal filtration and mitochondrial oxidative phosphorylation (OP) changes in radiotelemetered C57BL/6J mice that were forced to run in a heat chamber (37.5°C) until collapse (core temperature ~42.7°C). Mice were exposed to one (EHS) or two EHS events separated by 1 (EHS1), 3 (EHS3) or 7 (EHS7) days of recovery. Samples were collected 30 min, 3h, 1, or 7d after the first or second EHS exposure. Blood urea nitrogen (BUN; Abaxis VetScan analyzer) and a Mitochondrial Function Assay MitoPlate (Biolog) were used to assess renal filtration and OP changes, respectively. EHS1 mice experienced significantly greater thermal load (area under the heat curve) and dehydration compared to EHS, EHS3 and EHS7 mice (p&lt;0.001), but hypothermia depth during recovery was significant less pronounced than the other groups (~35°C vs. 32°C, respectively; p&lt;0.01). EHS1 mice showed 103% and 95% BUN decrease at 30 min and 3h of recovery compared with EHS, EHS3, and EHS7 groups, respectively (ANOVA, p&lt;0.001). Analysis of OP kinetics revealed that the following Citric Acid Cycle enzymes increased: Pyruvate Dehydrogenase (78%), Citrate Synthase (77%), Isocitrate Dehydrogenase (66%), Aconotase (59%) Alpha‐Ketoglutarate Dehydrogenase (50%), Succinate Dehydrogenase (18%), Fumurase (37%), and Malate Dehydrogenase (50%) 3h following EHS1, EHS3 or EHS7 (p&lt;0.05). All values were compared and normalized to naive control animals. The core temperature data indicate that EHS mice were partially acclimated prior to the second exposure on day 1 and this was sufficient to improve thermal tolerance (time in the heat before collapse) and reduce the severe sequelae during recovery. The minimal BUN changes EHS1 mice may be a consequence of increased glomerular filtration promoting normal renal hemodynamics. However, the kidney of EHS3 mice appeared to recover prior to the second exposure such that renal function was no longer adversely affected. The potential mechanism of these changes may be attributed to citric acid cycle kinetics of the renal mitochondria. These are the first data to indicate that partial heat acclimation in mice is sufficient to protect them against renal injury following a second heat exposure and this response has a 3d decay rate.Support or Funding InformationThe views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army, Department of Defense, or the U.S. Government. This abstract has been approved for public release with unlimited distribution.

Modeling the micro-explosion of miscible and immiscible liquid droplets

The research subjects are immiscible two-component droplets containing combustible and non-combustible liquids with a clear interface, as well as emulsion droplets. The key limitations are identified for the current models unable to adequately describe the critical (threshold) conditions and characteristics of micro-explosion. Experiments are conducted to obtain the heating times until breakup (delay times) and critical (threshold) temperatures triggering the droplet breakup. Two methods are used: a droplet is either suspended on a holder and placed into the heating chamber or it free-falls in a tubular muffle furnace. The developed models reliably describe the processes under study when two threshold conditions of droplet breakup are used: non-combustible component reaching its boiling temperature at the inter-component interface and a bubble or a group of bubbles in a droplet growing in size beyond critical values. In the experiments, the heating temperature ranges from 500 to 1400 K, the initial droplet size is between 1 and 3 mm, and the relative volume concentrations of the components are varied in the range of 10–90 vol%. An acceptable agreement has been established for the key heating and fragmentation characteristics at various heating temperatures and with component compositions of heterogeneous droplets. The maximum deviations of the theoretical droplet breakup times from the experimental ones do not exceed 40%. For critical (minimum and maximum) heating temperatures of the external medium sufficient for breakup, the deviations of theoretical and experimental data do not exceed 50 K. The study defines the conditions, in which the newly developed models can reliably predict the characteristics of micro-explosive droplet breakup. Hypotheses have been formulated explaining the differences between theoretical and experimental characteristics of micro-explosive droplet breakup. The research findings enable to outline the promising ways to improve micro-explosive breakup models for their further use in the secondary atomization of heterogeneous liquids, for instance, to develop the technologies of fuel ignition, thermal and flame water treatments, etc.

Improvement of the Mechanical Properties of Poly(Glycolic Acid) Fibers Through Control of Molecular Entanglements in the Melt Spinning Process

To improve the mechanical properties of poly(glycolic acid) (PGA) fibers prepared by the direct spin-drawing process, the concept of “melt structure control” was introduced. A heating chamber was installed in the vicinity of the spinning head and a low take-up velocity in the melt spinning process was adopted to reduce the Deborah number in the spin-line. As a result, improvement of the toughness of as-spun fibers prepared by the melt-spinning process was accomplished, and the drawn fibers of high-strength and high-toughness were obtained by applying an additional in-line drawing process. Entanglement density reduction in the melt spinning process was found to be suppressed by installing a heating chamber as well as by lowering the take-up velocity. Through the matching of the true stress versus true strain curves of in-line drawn fibers by shifting the curves along the true-strain axis, the network draw ratio of the drawn fibers was estimated and the master curves for individual spinning conditions were prepared. The master curves were found to show steeper increases from lower true-strains for the lower Deborah number conditions, whereas the increases in birefringence and strength of the drawn fibers proceeded from the lower network draw ratios.

The effect of additives and process parameters on the pilot-scale manufacturing of polylactic acid sub-microfibers by melt electrospinning

Sub-microfibers are polymer filaments less than 1 µm in diameter that can be fabricated into highly flexible materials with a large specific surface area. They are often produced by solvent or melt electrospinning. The former is a scalable process that produces thinner fibers but requires hazardous solvents, whereas the latter is more environmentally sustainable due to the absence of solvents but is more challenging to scale up. Here we investigated the manufacturing of biobased polylactic acid (PLA) sub-microfibers by melt electrospinning using a single-nozzle laboratory-scale device and a novel 600-nozzle pilot-scale device combined with conductive and viscosity-reducing additives: sodium stearate (NaSt), sodium chloride (NaCl) and a polyester-based plasticizer. We determined the effect of different additive concentrations on fiber diameter, thermal properties, polymer degradation, and fiber deposition. At the laboratory scale, the minimum average fiber diameter (16.44 µm) was accomplished by adding 2% (w/w) NaCl, but a stable spinning process was not achieved and the plasticizer did not reduce the melt viscosity. NaSt was the most effective additive in terms of adapting the material properties of PLA for melt electrospinning, but extensive polymer degradation occurred at higher temperatures and with higher concentrations of the additive. At the pilot-scale, the minimum average fiber diameter (3.77 µm) was achieved by adding 6% (w/w) NaSt, with a spinneret temperature of 195℃ and a spin pump speed of 0.5 rpm (0.16 cm3), without further improvements such as the integration of a heating chamber. The smallest single-fiber diameter (1.23 µm) was achieved under the same conditions but using a spin pump speed of 2 rpm. The scaled-up melt-electrospinning device therefore offers significant potential for the production of biobased sub-microfibers, bridging the gap between laboratory-scale and pilot-scale manufacturing.

Comparative study of LightWeight and Normal Concrete composite slabs behaviour under fire conditions

This paper presents the experimental study of lightweight concrete (LWC) and normal concrete (NC) composite slabs with steel decking profile exposed to standard time-temperature curve. LWC composite slabs are very efficient in terms of energy savings and sustainability due to their low values of thermal transmittance. In this study NC is used to compare the fire behaviour of LWC composite slabs. Dimensions of the slab are 160 mm thick, 1120 mm wide and 2030 mm long. In order to perform fire tests in the intermediate-scale samples, a non-standard furnace was designed and assembled. The furnace is composed of a heating chamber, a gas evacuation system and a portal frame. The heating chamber is made of a steel framework and refractory layers. The evacuation system, which has an auxiliary vein with a fan to introduce air, extracts hot gases. The portal frame is composed of steel profiles with a rotating beam equipped with a linear actuator to apply the load on the samples. This beam is opened to allow the slabs to be placed and closed during the test. Finally, experimental results show that the time of fire resistance is close to 30 min for both types of slabs. Free water within the slabs affects the temperature increase of concrete. Thus, the temperature distribution inside the slab follows a non-constant trend, due to the movement and evaporation of the free water. Furthermore, although there is de-bonding between the steel and the slabs, no spalling is detected.

A high-performance copper-based brake pad for high-speed railway trains and its surface substance evolution and wear mechanism at high temperature

High temperature is one of the most basic challenges faced by copper-based brake pads in emergency braking of high-speed railway train. Here, a novel copper-based brake pad was prepared and its tribological properties in the temperature ranging of 400–800 °C were studied by pin-on-disc tribometer equipped with heating chamber. The results show that compared with commercial copper-based brake pad, self-designed copper-based brake pad exhibits higher mean friction coefficient and smaller fluctuation of friction coefficient under all test conditions. The friction coefficient of self-designed copper-based brake pad is in the range of 0.35–0.45 at the temperatures up to 600 °C. At 800 °C, the failure mechanism of copper-based brake pad is related to the properties of graphite and copper. Graphite on the friction surface disappears after severe oxidation, resulting in the loss of lubrication of friction interface. Copper undergoes oxidation and softening. Oxidation makes copper unable to promote the formation of stable tribo-film, and the low-strength copper matrix after softening cannot effectively support the friction surface. Therefore, one of the key principles to design high-performance copper-based brake pad is to increase the oxidation resistance of graphite and the high temperature strength of copper matrix.

The effect of adenosine A2A receptor antagonist istradefylline on multiple organ dysfunction in heatstroke rats

Background: Global warming increases the incidence of heatstroke, which is the most severe heat illness. The mortality in patients with heatstroke is due to neurological disability and multiple organ failure caused by systemic inflammatory response. Adenosine A2A receptor antagonist has both neuroprotective and anti-inflammatory effects. Thus, we examined whether a new A2A receptor antagonist istradefylline has beneficial effects in heatstroke rats. Methods: Wistar rats were divided into four groups: (1) control group, with vehicle only (intravenous [iv] for 10 min); (2) control + istradefylline group, with 0.3 mg/kg istradefylline (iv for 10 min); (3) heatstroke group, rectal temperature reached 44.1°C, and then returned to room temperature with vehicle (iv for 10 min); and (4) heatstroke + istradefylline group, rectal temperature reached 44.1°C, and then returned to room temperature with 0.3 mg/kg istradefylline (iv for 10 min). During the experimental period, rectal temperature, heart rate, blood pressure, and pressor responses to norepinephrine (NE) were monitored. Before and after the rats were put into heating chamber, and after the rats returned to room temperature for 6 h, their blood was taken to analyze creatine kinase, lactate dehydrogenase, blood urea nitrogen, creatinine, alanine transaminase, albumin, total protein, and platelet count. In addition, the blood flow of tongue, left limb, and right limb was also monitored. Finally, we examined their survival rate. Results: In the present study, heatstroke rats showed high core body temperature accompanied with cardiac abnormalities and multiple organ dysfunction, mimicking the clinical manifestations of heatstroke patients. Treatment of heatstroke rats with istradefylline only partially improved platelet loss and vascular hyporeactivity to NE. However, istradefylline had no significant effects on cardiac abnormalities and multiple organ dysfunction in rats with heatstroke. Conclusions: These results suggest that although istradefylline has a mild impact on abnormal platelet count and pressor response to NE in heatstroke, both effects are unlikely to counteract multiple organ dysfunction and the mortality.

Validation of Hygrothermal Simulations with Wall Performance Experiments in an Environmental Chamber

Oak Ridge National Laboratory is developing a web tool, built on a rule-based expert system, that aids stakeholders in designing energy-efficient moisture-durable walls. Currently, the tool’s expert system database is mostly populated with expert opinion, but work is being done to incorporate durability assessment based on stochastic hygrothermal modeling. Chamber experiments have been conducted to validate the hygrothermal models. The measured temperature and humidity have been compared with those predicted by the hygrothermal model. Experiments and comparison to one-dimensional hygrothermal modeling results were completed with two walls, a Structural Insulated Panel (SIP) based wall and a Concrete Masonry Unit (CMU) based wall. The two walls were succumbed to typical Chicago weather in ORNL’s Heat, Air and Moisture chamber. The walls were sequentially exposed to different scenarios, including diffusion, wetting, air leakage and solar radiation. For the most part, the hygrothermal simulations can be successfully used to predict the performance of these wall systems for the moisture transport phenomenon. Errors between measured and simulated values decreased as measurements got closer to the interior side of the wall. The root mean square error was larger for relative humidity (up to 17.5%-RH for CMU) than for temperature (up to 4.5°C for CMU wall). The errors were larger for the CMU wall than the wood frame wall. The phenomenon, including liquid water, caused large discrepancies between measurement and simulation results, and simulated results showed slower drying of materials than measured results. The one-dimensional nature of the simulation model made simulating air leaks difficult but not impossible.

High-temperature spectral thermometry in conditions of intense microwave electromagnetic fields

In this paper, a practical application variant of the high-temperature spectral thermometry method for controlling the temperature of a dielectric object heated in a high-intensity microwave electromagnetic field is proposed. The advantages of using the spectral pyrometry method over the methods of color and brightness pyrometry when registering high temperatures (from 500 °C and above) are described. The optical fiber cable used in this method, which receives thermal radiation from an object heated in the microwave field, is subject to the negative influence of the electromagnetic field, which leads to its unacceptable heating and failure. To eliminate this phenomenon, a non-standard use of an cutoff waveguide placed not outside, but inside the microwave heating chamber is proposed. It is shown that this solution completely eliminates the negative influence of the electromagnetic field on the fiber optic cable and allows placing the receiving end of the cable in close proximity to the object being heated. The calculation of geometric parameters of the cutoff waveguide for the operating frequency of the electromagnetic field of 2450 MHz is given.

Performance test of prototype of mini compact crucible furnace

Mini compact crucible furnace prototype is aimed at reducing dimensions and weight without sacrificing capacity. The performance test was conducted in order to found its weaknesses. The performance parameters tested were crucible, support, and exhaust pipe as economizer. The crucible dimensions are (ø170 x 250) mm and (ø110 x 210) mm while the support’s high are 80 mm and 40 mm. The test was done in two conditions which are with and without economizer. The performance is defined by the temperature change rate in melting 3 kg of aluminium. A digital infrared thermometer was used to measure temperature changes. The result shows that position of economizer is too low so the residual gas combustion could not smoothly thrown out and it flow back and collide with the combusted gas from high pressure stove below. Reducing the heating chamber could enhance the furnace efficiency but economizer should be in proper position and support should be in optimum height. Redesign of heat insulator should be done related to the smash by combusted gas from high pressure stove.

Impact of twisted alignment on the smectic layer structure of ferroelectric liquid crystal

The twisted aligned cell of ferroelectric liquid crystal is assessed through electro-optical and dielectric spectroscopy and a comparison is made with antiparallel planar aligned cells of the same thickness around 8 μm. The study has been carried in two types of twisted aligned samples, one is natural cooled sample in the heating chamber and another is slow cooled at the rate of 0.05 °C/min. The influential distinct results have been observed in natural cooled twisted cells. In natural cooled cells, the helicoidal structure at the surface and in the bulk of the cell is distinct and contributes separately to the response of the cell. On the other hand, at the same cooling condition in twisted cell, the smectic layers are in a twisted state resulting into a non-uniform helical structure, therefore, the partial helicoidal unwound structure at the surface and in the bulk of the cell are not observed contributing to the dielectric permittivity separately unlike in planar aligned cell. The twisted cell is found to induce the restoring force within the sample. However, the slow cooling cycles on the twisted cell changes to the strain free equilibrium state, whereas the behavior of the planar sample cell remains unchanged. The studies are significant for the display devices based on twisted alignment of FLC cells.

Transformation of Plastic Waste into Fuel by Pyrolysis

Given the scenario of difficulty of equalizing treatment and disposal costs, environmental risks and reduction of mass and volume of waste, the pyrolysis process presents itself as a promising option of heat treatment for the most varied types of waste. The present work aims to enable the transformation of plastic waste into combustion engine fuels. And specifically, perform the pyrolysis process for fuel generation through plastic waste, and describe the benefits generated by the transformation process. The methodology used is the case study, with qualitative approach. To obtain the fuel, it was necessary to use equipment that can degrade the plastic waste by heating it, being possible with the use of a pyrolysis oven. Heating the plastic residue inside the oven without the presence of oxygen causes the residue to melt without burning, releasing vapors, which upon exiting the heating chamber and finding the condensation chamber turns the vapor into liquid, more precisely into fuel oil. However, it was noticed that the transformation of plastic waste into fuel through pyrolysis causes the reduction of the impacts generated by solid waste disposal in the environment, water and air. In addition, it enables a new form of fuel generation, since previously it could only generate fuel from oil.