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A computational fluid dynamics (CFD) simulation was developed to simulate an industrial cheese chilling process. Forced air chilling experiments were performed on blocks of agar (cheese analogue) to simulate the airflow and product arrangement in a section of an industrial cheese chilling tunnel. The flow field was solved at steady-state and decoupled from the heat transfer processes. The six blocks of agar were placed in a polystyrene test chamber that was in turn placed in an environmental testing chamber. Temperatures were measured at the surfaces and the geometric centre of the tested blocks of agar. Good agreement was observed between predicted and experimental data. Having been validated, the model was used to generate simple correlation models for predicting the volume-averaged temperature of blocks of cheddar cheese and mozzarella cheese during industrial chilling

BackgroundOxygen-delivering modalities like humidified high-flow nasal cannula (HFNC) and noninvasive positive-pressure ventilation (NIV) are suspected of generating aerosols that may contribute to transmission of disease such as coronavirus disease 2019. We sought to assess if these modalities lead to increased aerosol dispersal compared to the use of non-humidified low-flow nasal cannula oxygen treatment (LFNC).MethodsAerosol dispersal from 20 healthy volunteers using HFNC, LFNC and NIV oxygen treatment was measured in a controlled chamber. We investigated effects related to coughing and using a surgical face mask in combination with the oxygen delivering modalities. An aerodynamic particle sizer measured aerosol particles (APS3321, 0.3–20 µm) directly in front of the subjects, while a mesh of smaller particle sensors (SPS30, 0.3–10 µm) was distributed in the test chamber.ResultsNon-productive coughing led to significant increases in particle dispersal close to the face when using LFNC and HFNC but not when using NIV. HFNC or NIV did not lead to a statistically significant increase in aerosol dispersal compared to LFNC. With non-productive cough in a room without air changes, there was a significant drop in particle levels between 100 cm and 180 cm from the subjects.ConclusionsOur results indicate that using HFNC and NIV does not lead to increased aerosol dispersal compared to low-flow oxygen treatment, except in rare cases. For a subject with non-productive cough, NIV with double-limb circuit and non-vented mask may be a favourable choice to reduce the risk for aerosol spread.

The test chamber in an open-loop wind tunnel is a critical part for aerodynamic experiment. The study aims to assess the feasibility of the new design of test chamber for open–loop wind tunnel by studying the fluid characteristic and the average pressure in the test chamber. The study is done by a series experimental test for the test chamber. From experimental test, the downstream velocity in the test chamber is increased from 8.9 m/s to 12.72 m/s where the pressure gradient is ranging from 6.19 to 8.398 atm with the overall turbulence intensity for the test chamber is 0.749%. According to the results, the designed open-loop wind tunnel is acceptable to use for an aerodynamic test.

SUMMARY The aim of this study was to compare the effects of accelerated aging on the overall color stability of potentially color adjusting commercial resin-based composite resins. Thirty specimens (10 mm diameter and 2.5 mm thick; n=6) were fabricated using five different materials: Estelite Omega, GC Kalore, Venus Pearl, Harmonize, and Omnichroma. Color measurements were taken for each sample using a spectrophotometer before and after submitting samples through the artificial aging process (Q-sun Xenon Test Chamber, 102 min light at 63°C black panel temperature; 18 min light and water spray per ASTM G155) for a total of 300 hours (12.5 days). The total color difference (ΔE*ab) was calculated using SpectraMagic NX software and analyzed using one-way analysis of variance and Tukey test. The results for color change (ΔE*ab) were statistically significant. Omnichroma and Venus Pearl presented superior color stability and the lowest overall color change, whereas GC Kalore and Harmonize presented significant color change that would be considered clinically unacceptable (ΔE*ab > 3.3).

Lack of attention to the effect of laboratory conditions on the results of asphalt mixture tests, especially these of the warm mix asphalt (WMA), makes the analysis of results misleading. Thus herein, after examining the research on WMA and factors affecting test results in laboratory conditions, the effect of three parameters including short-term aging (asphalt binder storage in the oven), curing time (from construction to placement in the test chamber), and thermal equilibrium time (from placement in the test chamber to the test onset) were investigated on the characteristics of WMA at mid-temperature. To simultaneously examine these three factors, 36 modes were developed to evaluate their effect on the stiffness modulus and fatigue cracking, using the indirect tensile stiffness modulus test (ITSM) and indirect tensile fatigue test (ITFT), respectively. Results of the experiments showed that increasing the time of asphalt binder placement in the oven for 2–6 h significantly increased the stiffness modulus of the mixture, which reduced the fatigue life of the WMA. With increasing the curing time and improving the adhesion between asphalt binder and aggregates, the stiffness modulus and fatigue life of the specimens increased; however, by increasing the thermal equilibrium time, the stiffness modulus and fatigue life of the specimens decreased due to asphalt binder viscoelastic behavior and temperature sensitivity. Results of statistical analyses revealed that short-term aging, curing time, and thermal equilibrium time in laboratory conditions were effective on the stiffness modulus and fatigue life of WMA at a 95% confidence level.

Hydrocarbons are being considered as an energy efficient alternative substance to HCFC-22 in ACs. Better thermo physical properties of HCs results higher energy efficiency in split air conditioners than HCFC-22. However, safety of HC substances needs to be addressed when it is used in ACs. This paper focus on a typical inverter operated SAC with 5.2 kW nominal cooling capacity for performance evaluation. Various tests have been carried out on SAC in well-equipped psychrometric test chamber maintaining test conditions as prescribed in Indian Standard (BIS 1391 part-1) for full capacity and half capacity of test unit. Initially HCFC-22 was tested to establish baseline performance. HCs chosen are HC-290 and its blend (50% HC-290 and 50% HC-1270 by weight) were tested for as a drop-in replacement for HCFC-22. Indian SEER of SAC with HC-290/HC-1270 blend achieved was 4.91 as against 5.11 for HC-290. For HC-290 and HC-290/HC-1270 blend, ISSER is about 20.2% and 15.5% higher respectively than HCFC-22.

Purpose This paper aims to study and assess a new approach for prediction of changes of pressure during gas discharge inside the room protected by fixed gaseous extinguishing system by computational fluid dynamics (CFD) simulations. Design/methodology/approach The research program consisted of two stages. The first stage was dedicated to the experimental measurements of pressure changes during extinguishing gas discharge into the test chamber in a real scale (70 m3), for two relief openings that differ in their area. The next step was about performing CFD simulations forecasting pressure changes during gas discharge into the numerically represented test chamber. Estimation of the correctness and usefulness of the CFD model was based on a comparison of the CFD results with standard calculations and experimental measurements. Findings Numerical modelling of pressure changes during the carbon dioxide discharge was very close to the experiment. The obtained results had sufficient accuracy (in most cases relative error Originality/value Conducted research confirms the viability of the new approach in modelling the pressure changes and indicates additional benefits of the numerical analyses in the determination of the fire safety of protected premises.

The article presents the methodology of testing sliding bearings with a flexible shell, focusing on the issue of temperature increase during experiments for a specific time interval of the START-STOP test cycle. Selected material pairs, used in previous studies, were used in the experiment. The stand used for tests in the start-stop cycle was developed under the project POIG.01.03.01-00-027 / 08-00 at the Faculty of Technical Sciences UWM in Olsztyn.

There are no ASHRAE/HVI standards for characterizing or specifying acceptable values of capture efficiency (CE) (i.e. percentage of cooking-contaminants captured/exhausted by a household rangehood)...

Inhalation doses due to radon and thoron are predominantly due to the inhalation of progeny of Radon and Thoron. The progeny/decay-products of radon and thoron are particulates unlike their parent gas and exhibit different physical properties like attachment to the aerosols and deposition on different surfaces. All these properties in turn depend on the environmental conditions such as air velocity, aerosol concentration, attachment rate, etc. The role of air velocity on deposition on surfaces decides the progeny particles left in the air for inhalation. Therefore, in the present work, we have studied the effect of air velocity on the inhalation dose due to radon and thoron progeny at the centre of a 0.5-m3 calibration chamber as well as on all surfaces. Hence, the studies were carried out at different air velocities, and inhalation doses were measured using deposition-based direct radon and thoron progeny sensors.

Purpose: In this paper, in vivo methods of estimation of the shear modulus and hydraulic permeability of subcutaneous tissue of lower limb are presented. Methods: The experimental technique is based on single- or two-chamber inflation-deflation tests in which temporal changes in limb circumference under the test chamber for cyclic loading are registered. Simplified models for fast undrained deformation and slow creep of oedematous tissue with squeezing out interstitial liquid were considered. Finite element simulations of the chamber test within a finite deformation poroelastic model were elaborated. Results: Formulas necessary to estimate the shear modulus and permeability of subcutaneous tissue were derived and then tested or calibrated using the results of poroelastic simulations. An example of application of the derived formulas for clinical data obtained from the chamber test was discussed. Conclusions: A simple in vivo methods of estimation of the hydromechanical properties of lymphedematous tissue (shear modulus and permeability) were proposed. The strengths and weaknesses of the proposed methodology were discussed.

The resonant frequency of the quartz resonator is related to the ambient temperature. This paper designs an automatic test system for frequency-temperature characteristics of quartz resonator cluster. The system based on FPGA(field programmable gate array) and temperature sensor collects the resonant frequency and ambient temperature. It combines computer and FPGA to obtain 6 resonator frequency values and 1 temperature value per second by polling. Applying the system and the high and low temperature test chamber, the resonant frequency of the cluster quartz resonator at different temperatures can be obtained in real time, which greatly improves the measurement accuracy and density of the data.

The main aim of this study was to reveal the influence of spoiler on thickness uniformity of ice layer in environmental test chamber by experiments and numeric, while analyse the effects of variable fan speed and temperature on the results parameters. The results parameters were ice thickness and ice shape. The second aim was to study the effect of different droplet sizes on ice shape. The results revealed that the droplet size had effects on the ice shape, and the spoiler had strong effects on the ice uniformity: (1) The spoiler could significantly affected the trajectory of the droplets by disturbing the air flow, and then improved the ice thickness uniformity; (2) Increasing the fan speed could effectively increase the ice thickness in a limited time; (3) The droplet size had a direct impact on the ice shapes, and different droplet sizes would result in different ice shapes; (4) Temperature also has an important impact on the ice shape, and account for the formation of different ice shapes, the dual effects of temperature and droplet size should be considered comprehensively. The experience results provide the theoretical and engineering technical bases and prevents the occurrence of owe experiment in the atmospheric icing laboratory.

The tightness of electro-technical components for dust entrapment is an extremely important parameter to be considered for effective functioning. International Electro-technical Commission (IEC) developed standards for testing the parts under severe environments like rain, dust etc. The procedure for developing and conducting the dust proof test is known by IEC as 60068-2-68 standard. The blower is an essential component used in the dust test system in order to create a forced airflow along with dust to simulate a dusty environment. The radial tip centrifugal blower is designed in this work for the application of dust test chamber. The pressure and velocity of airflow at the outlet of the radial tip centrifugal blower is mostly influenced by inlet blade angle (b1), impeller diameter (D2) and impeller width (b). The design procedure is elaborated and the above said design parameters are optimized using iterative procedure using MATLAB software. A numerical analysis is carried out using ANSYS Fluent software for the design of Taguchi L9 orthogonal array. In the perspective of further exploring the relationship between design parameters of blower and output parameters like pressure and velocity, a statistical analysis is carried out using Design-Expert software. The optimized design parameters are then used for manufacturing the blower. The experimental test is carried out on the designed blower. The experimental, numerical and statistical results for the optimized design parameters are compared and known to be in good consensus.

A method for testing sliding bearings with an elastic bearing liner was presented in the paper with a focus on the issue of selection of particular time intervals of the START-STOP test cycle. Then, results of the tests carried out according to the selected material combinations were presented. The working cycle of foil bearings tested on the test stand was performed in an automatic mode at the set number of sequences start-work-rundown-stop. Due to the highest use of sliding bearings during start and rundown of a machine, this type of tests is essential for selection of relevant sets of material for bearing elements. The article also presents the use of a thermo-visual camera for identification of additional thermal loads and manners of temperature stabilization in the test chamber.

A sensitive and reliable method based on environment test chamber coupled with thermal desorption and gas chromatography-mass spectrometry (ETC-TD-GC/MS) was developed and validated for the determi...

In this study we have examined the gender-wise differences in sleeping behavior of volunteers subjected to thermo-electric air conditioning test-room conditions. For this purpose, fifteen males and fifteen female subjects were recruited. After filling the Pittsburgh Sleep Quality Index (PQSI) questionnaire, each subject was required to sleep in the room under all the three study conditions i.e. normally ventilated room (NH), thermoelectrically cooled room at input power supply of 600 W and thermoelectrically cooled room at power input of 720 W. Each subject was required to complete one night's sleep in each of the study conditions. Objective sleeping parameters such as body movement, heart rate, sleeping quality were measured using a Fitbit Alta HR watch. A subjective assessment of the sleep quality was also done after each session. The observed findings were compared for all the three conditions for each subject. It was found that male subjects had an overall better sleep quality at a lower surrounding temperature as compared to the female subjects. For female subjects the indoor environment was found to be comfortable to slightly cold when the thermoelectric cooling system was operated at 600 W. On the other the male subjects had a better sleep quality at 720 W. Based on these cooling requirements, males are estimated to consume 485 kWh more energy annually (which would result in CO2 emissions in excess of 6 tons) as compared to females to maintain comfortable sleeping environment.

The purpose of this study is to analyse the heat flux difference and examine applicability of the heat flux sensor along with various sensor attachment methods. Using multiple sensors and various t...

In a liquid desiccant dehumidifier, the air-to-solution flow direction plays an important role in the dehumidification performance and the physical size of the dehumidifier tower. In this research, the dehumidification performance of counter-flow and cross-flow liquid desiccant dehumidifiers were compared via a series of experiments carried out in the environmental test chamber. To predict the dehumidification performance of both flow type dehumidifiers in various operating conditions, empirical models returning the dehumidification effectiveness and the enthalpy effectiveness, which were adopted as performance indices, were also derived based on the experimental data. From the sensitivity analysis conducted by using the proposed empirical correlations, it was observed that when the inlet air humidity ratio increased from 10.1 g/kg to 22.7 g/kg, the dehumidification effectiveness and enthalpy effectiveness of the counter-flow liquid desiccant dehumidifier increased from 51.2% to 82.4% and 40.2% to 72.5%, respectively. Meanwhile, both effectiveness values of the cross-flow dehumidifier increased from 62.3% to 63.4% and 46.3% to 55.0%, respectively. Likewise, when inlet solution temperature varied from 15.2 to 31.1 °C, the dehumidification effectiveness and enthalpy effectiveness of the counter-flow type dehumidifier decreased from 71.7 to 45.4% and 64.4 to 47.3%, respectively, while those of a cross-flow type dehumidifier decreased from 65.3 to 54.8% and 55.8 to 45.2%. Consequently, one may conclude that the cross-flow liquid desiccant dehumidifier would provide relatively stable dehumidification performance regardless of the changes in operating parameter, but the cross-flow dehumidifier may have limited dehumidification performance, especially at the lower desiccant solution temperature and in highly humid process air conditions.

This paper investigates the gas sensing characteristics of the MOSFET-type sensor having an inkjet-printed WS2 sensing layer. The drain current of the gas sensor increases when NO2 gas is injected into the test chamber since NO2 gas is an oxidizing gas that extracts electrons from the sensing layer. On the contrary, the drain current decreases when H2S gas is injected into the test chamber since H2S gas is a reducing gas that donates electrons to the sensing layer. In both cases, the change of the drain current increases as the gas concentration increases. However, for other gases (NH3 and CO2), the gas sensor has a small change of the drain current. The responses of the gas sensor to 10 ppm NO2, H2S, NH3, and CO2 gases are 15.20%, 7.18%, 1.66%, and 3.02%, respectively. Therefore, the WS2 sensor has a high selectivity for NO2 gas among the four target gases.

Exposure to ultrafine airborne particulate matter (PM1.0) poses a significant risk to human health and well-being. Examining the effect of submicron water droplets on the removal of ultrafine PM is timely and important for mitigating indoor ultrafine PM, which is difficult to filter out from incoming air. In this study, submicron water droplets were made by using a nanoporous membrane and an ultrasonic module of a commercial household ultrasonic humidifier (UH) for effectual ultrafine PM removal. The effect of water droplet size on indoor PM removal was experimentally investigated. Variations in the normalized PM concentration, removal efficiency and deposition constants were evaluated by analyzing the temporal variation in PM concentration inside a test chamber. The measured PM deposition constants were compared with the results of other previous studies. As a result, submicron water droplets of 800 nm in mean diameter were generated by ultrasonic module combined passive nanoporous membrane, and PM1.0 concentration decreased by 30% in the initial 30 min. Compared with micron-sized water droplets, PM1.0 removal efficiency improved by approximately two times higher. Moreover, the substitution of the experimental results into a theoretical model ascertained that PM collection efficiency is increased by approximately 103 levels as the size of water droplets decreases. These results would be utilized in the development and implementation of effective strategies for indoor PM removal.

Emission testing of volatile organic compounds (VOC) from materials and products is commonly based on emission test chamber measurements. To ensure the comparability of results from different testing laboratories, their measurement performance must be verified. For this purpose, Bundesanstalt fur Materialforschung und -prufung (BAM) organizes an international proficiency test (round robin test, RRT) every two years using well-characterized test materials (one sealant, one furniture board, and four times a lacquer) with defined VOC emissions. The materials fulfilled the requirements of homogeneity, reproducibility, and stability. Altogether, 36 VOCs were included of which 33 gave test chamber air concentrations between 13 and 83 µg/m3 . This is the typical concentration range to be expected and to be quantified when performing chamber tests. Three compounds had higher concentrations between 326 and 1105 µg/m3 . In this paper, the relative standard deviations (RSD) of BAM round robin tests since 2008 are compared and the improvement of the comparability of the emission chamber testing is shown by the decrease of the mean RSD down to 28% in 2018. In contrast, the first large European interlaboratory comparison in 1999 showed a mean RSD of 51%.

Atmospheric particulate matter or PM is one of the pollutants certainly most considered by professionals, both for the impact it has on the environment and for the impact, it has on human health. The official measurement methods for the detection of PM give information at long intervals and in pre-established sites giving a poor resolution from this point of view. For years, sensor manufacturers have tried to address this shortcoming with new portable devices, which have a very low sampling time (a few seconds) and a low price called the Low-Cost PM Sensor (LCPMS). This work shows a comparison of the performance of an LCPMS set. The test is carried out in the laboratory where a test chamber has been created capable of providing a controlled environment in which to test the devices.

This invited paper describes prototype SiC JFET integrated circuit (IC) and packaging technology that has produced arguably the most harsh-environment durable electronics ever demonstrated. Prototype medium-scale integration (MSI) ICs fabricated by NASA Glenn Research Center have successfully operated for over 1 year in 500 °C air-ambient, over 60 days in 460 °C and 9.3 MPa pressure caustic Venus surface environment test chamber, from -190 °C to +812 °C, and radiation exposure through 7 MRad(Si) total ionizing dose and 86 MeV-cm2/mg heavy ion strikes. Recent on-going work focused on upscaling this “go anywhere” IC capability from MSI to large-scale integration (LSI) prototype via benchmark memory ICs is described.

Purpose: In 2015, the National Institute for Occupational Safety and Health (NIOSH) published a draft vapor containment protocol to quantitatively evaluate combined liquid, aerosol, and vapor containment performance of commercially available closed-system drug-transfer devices (CSTDs) that claim to be effective for gas/vapor containment within a controlled test environment. Until the release of this proposed protocol, no standard method for evaluating airtightness of CSTDs existed. The aim of this study was to evaluate six commercially available CSTDs utilizing NIOSH draft protocol methodology to evaluate vapor containment under a robust vapor challenge. Methods: In this study, six commercially available CSTDs were tested utilizing draft NIOSH vapor containment protocol methodology to simulate drug compounding and administration using 70% isopropyl alcohol (IPA) as the challenge agent. All device manipulations were carried out in an enclosed test chamber. A Miran sapphIRe gas analyzer was used to detect IPA vapor levels that escaped the device. Study test included the two tasks designated by the NIOSH protocol, with additional steps added to the evaluation. Tasks were repeated 10 times for each device. Results: Only three of the six tested CSTDs (Equashield®, HALO®, and PhaSealTM) had an average IPA vapor release below the quantifiable performance threshold (1.0 ppm) for all tasks performed. This value was selected by NIOSH to represent the performance threshold for successful containment. The remaining three CSTDs had vapor release above 1 ppm at various times during the IPA manipulation process. Conclusion: Equashield®, HALO®, and PhaSealTM devices tested met the 2015 NIOSH protocol quantifiable performance threshold, functioning as a truly closed system. Quantifiable effective data may be useful in product selection.

This paper presents the temperature-controlled test chamber for Partial Discharge and Polarization and Depolarization Current test of dielectric liquid including impregnated pressboards with the various conditions. Besides, the temperature of the test specimen is controlled between room temperature to 300°C. The temperature distribution in the test chamber was simulated. Besides, the electric field stress at the electrodes were simulated. Furthermore, different kinds of sensors such as a thermocouple, gas sensors, and so on were designed to be equipped within the test chamber. From the simulated result, both electric field stress and temperature distribution were in the given conditions.

Results are presented from studies performed in a test chamber on clean room garments used, laundered, and sterilized (autoclaved 20 min at 121°C), 50, 60, and 70 times, and garments used, laundered, and sterilized with a prolonged autoclave cycle 50 times. The source strength is described as the mean value of the number per second of airborne particles and aerobic colony-forming units (CFUs), respectively, emitted from one person dressed in the system to be evaluated. Results from body-box tests have been used to calculate theoretical expected concentrations of airborne aerobic CFUs and particles (≥0.5 µm) in clean rooms with different numbers of people present and at different airflows (m3/s). Theoretical expected concentrations of airborne aerobic CFUs are often below the detection level of traditional measuring equipment.

It is well known that fans have been widely used in many applications for cooling and ventilation purposes. However, in a considerable portion of these applications, fans are being operated in highly resistive environments such as ITE (Information Technology Equipment) in which the fan will be installed in a narrow space surrounded by many obstacles. These obstructions lead to increased vibration and degradation in fan performance. As the fans’ pressure-flow rate (P-Q) curve is used to indicate the fan's performance, previous studies have investigated the blockage effect on the fan's P-Q curve using a flow test chamber. However, these studies measured the pressure from a considerable distance from the fan. Hence, developing a new technique that can measure the pressure closer to the fan will help in conducting a better understanding of how fans react to the presence of obstruction. In this work, pressure readings were taken through pressure taps that were drilled in a plexiglass sheet an experimental setup was designed to study the server chassis blockage effect on the fan performance by getting a multiple pressure reading right across the fans. These measurements were compared with pressure measurements that were collected from the flow test chamber at a considerable distance from the fan.

Soiling problems are always encountered for equipment installed in outdoor environments, such as headlamps of automobiles, air conditioners, solar collectors, and so on. How to prevent soiling prob...

In the United States, there are more than 120,000 nail salons in which workers could be potentially exposed to a number of volatile organic compounds (VOCs) used in various procedures. Measuring workers exposure in the field is time-consuming and could be very expensive. The purpose of this study was to estimate the VOC levels in the proximity of workers in nail salons through simulating the application process of some popular nail polishes in a laboratory chamber. The worst-case scenario was defined as a worker’s exposure during nail polish application to one set of fingernails every 15 minutes for an 8-hour shift (total nail sets = 32). Nail polish was applied on paper plates in a flow-controlled test chamber. Air was sampled during the application of five different nail polishes for 8 hours using passive air samplers and the experiment was triplicated. Passive samplers were used for VOCs and formaldehyde. In this worst-case scenario setting, a total of 17 VOCs were detected, with eight that were found in all the samples. The mean concentration of butyl acetate (161-330 ppm, parts per million) and ethyl acetate (440 ppm) exceeded the threshold limit value (TLV) of 150 ppm and 400 ppm, respectively. Formaldehyde was analyzed separately and the mean concentrations exceeded the TLV of 0.10 ppm in all types of nail polish, ranging from 0.12 ppm to 0.22 ppm. Occupational safety and health professionals could use these data to increase awareness of workers’ potential exposure to high levels of VOCs in nail salons and recommend practical measures to reduce potential exposures.

Cooking oil fumes contain polycyclic aromatic hydrocarbons (PAHs), which are known to cause chronic human health effects; hence long-term exposure data is required for determining workers’ exposure profiles and the resultant health risks. However, due to both time and cost constraints, previous studies were performed on a cross-sectional basis. To date, mathematical models have been widely used for predicting long-term exposures in the industrial hygiene field. The aims of this study were to develop suitable predictive models for establishing long-term exposure data on cooking workers. The whole study was conducted in a test chamber with an exhaust hood installed 0.7 m above a deep-frying pan and operated at flow rates of 2.64–5.16 m3 min–1. The cooking process that we selected for testing used peanut oil to deep-fry chicken nuggets at 200°C. An IOM inhalable sampler and an XAD-2 tube were successively used to collect particle- and gas-phase PAHs, respectively. All of the collected samples were analyzed for 21 PAHs using a gas chromatograph (GC) with tandem mass spectrometry (MS/MS). The results showed that the emission rates of the total-PAHs in the gas-phase and the particle-phase were 1.45 × 104 and 2.14 × 102 ng min–1, respectively. The capture efficiencies of the exhaust hood for the total-PAHs were 39.1–76.5%. The resultant fugitive emission rates of the gas-phase and the particle-phase ranged from 3.41 × 103 to 8.82 × 103 and from 5.03 × 101 to 1.30 × 102 ng min–1, respectively. As no significant difference in the sampling results of the total-PAHs was detected between the chef-zone (i.e., the near zone) and the helper-zone (i.e., the far zone), the well-mixed room (WMR) model was adopted for estimating the exposures of all workers. A good correlation (y = 0.134x + 75.3; R2 = 0.860) was found between the model predicted results (x; 3.25 × 102–1.57 × 103 ng min–1) and the field sampling results (y; 1.36 × 102–2.92 × 102 ng min–1), indicating the plausibility of using the proposed approach to establish a long-term exposure databank for the cooking industry.

Effective spatial disinfection systems are required for human health care, public hygiene, and food and medicine manufacturing. Although some aerosolized disinfectants were already applied to its purpose, accurate evaluation systems were under constructed. In this study, the spatial sporicidal activity of aerosolized hypochlorite solution (AHS) to dormant cells, Bacillus subtilis spores, was evaluated by an originally designed chamber system. In the test-chamber, AHS was supplied and existed as micro-droplets, and environmental relative humidity (RH) could be controlled. Available chlorine (AC) exposure was also controlled with appropriate AC loading but was influenced by the acidity of AHS. Our results indicated that inactivation of spore was depend on AC exposure amount and time. On the other hand, unsaturated environmental RH markedly decreased spore inactivation. This study indicated that our test-chamber system can provide reproducible test data under a homogeneous air condition, and, thereby, that the data obtained by the chamber system should contribute to predicting the AC-required dose to disinfect a whole building.

The impact of a bioinsecticide based on azadirachtin (Ozoneem trishul 1 %) on the abudance of mushroom flies (Sciaridae: Diptera) was compared to the effect of a commercial formulation of the malathion-based chemical insecticide Etiol tecni. Experiments were conducted in three growing chambers (B6, B7 and B8) of a commercial mushrom farm ?Delta Danube? d.o.o., Kovin. Casing treatments were performed in eight replications in a random block design. The azadirachtin-based bioinsecticide was applied in chamber B8 four times (0.5 ml/m2): during casing and later at seven-day intervals. The standard chemical insecticide based on malathion was applied in chambers B6 and B7 twice (2 x 0.3 ml/m2), on the third and sixth day after casing. In all three chambers, the abudance of mushroom flies was monitored by using yellow sticky traps, which were collected weekly and replaced with new ones four times at seven days intervals. The yellow sticky traps were examined in the laboratory under a binocular microscope to determine the presence and density of mushroom flies. Only one species of mushroom fly, Lycoriella ingenua (Dufour), was found on the yellow sticky traps throughout the experimental period. The average number of sciarid flies per mushroom block 15 and 22 days after treatment (DAT) was significantly lower in the test chamber B8 than in chambers B7 and B6, while there was no significant difference 30 and 36 DAT, compared to the control chamber B6. The average number of sciarid flies per mushroom row throughout the experiment was significantly lower in the test chamber B8 than in chambers B6 and B7. The results of our study suggest that the azadirachtin-based bioinsecticide can suppress populations of the mushroom fly L. ingenua and may provide a good alternative to conventional chemical insecticide.

The potential of inactivating indoor bacteria aerosols using a novel rotating ultraviolet-C (UV-C) light-emitting-diode (LED) system was investigated. The system was installed in the upper level of a full scale chamber and its effectiveness against aerosolized E. coli, S. marcescens, and S. epidermidis under the well-mixed with stationary UV-LED scenario was initially tested. The estimated susceptibility values were 1.068, 1.148, and 0.156 m2/J for E. coli, S. marcescens, and S. epidermidis, respectively. Three additional scenarios of experiments were conducted, in which E. coli was aerosolized into the test chamber and then allowed to decay under (i) poorly-mixed condition with stationary system, (ii) well-mixed with rotating system, and (iii) poorly-mixed conditions with rotating system. Our results showed no significant difference between the performance of stationary and rotating UR-UVGI-LED systems under a well-mixed condition. While the performance of the stationary UR-UVGI-LED system under a poorly-mixed condition decreased by 52.90–79.38 % compared to a well-mixed condition, rotating the UR-UVGI-LED system under a poorly-mixed condition, compared to the stationary system, enhanced its performance by 22.36–49.86 %. Thus, our proposed rotating irradiation offers great potential for application in environments where bioaerosols are unevenly distributed in a built environment.

Extensive use of halogenated flame retardants (HFRs) and organophosphate esters (OPEs) has generated great concern about their adverse effects on environmental and ecological safety and human health. As well as emissions during use of products containing such chemicals, there are mounting concerns over emissions when such products reach the waste stream. Here, we review the available data on contamination with HFRs and OPEs arising from formal waste treatment facilities (including but not limited to e-waste recycling, landfill, and incinerators). Evidence of the transfer of HFRs and OPEs from products to the environment shows that it occurs via mechanisms such as: volatilisation, abrasion, and leaching. Higher contaminant vapour pressure, increased temperature, and elevated concentrations of HFRs and OPEs in products contribute greatly to their emissions to air, with highest emission rates usually observed in the early stages of test chamber experiments. Abrasion of particles and fibres from products is ubiquitous and likely to contribute to elevated FR concentrations in soil. Leaching to aqueous media of brominated FRs (BFRs) is likely to be a second-order process, with elevated dissolved humic matter and temperature of leaching fluids likely to facilitate such emissions. However, leaching characteristics of OPEs are less well-understood and require further investigation. Data on the occurrence of HFRs and OPEs in outdoor air and soil in the vicinity of formal e-waste treatment facilities suggests such facilities exert a considerable impact. Waste dumpsites and landfills constitute a potential source of HFRs and OPEs to soil, and improper management of waste disposal might also contribute to HFR contamination in ambient air. Current evidence suggests minimal impact of waste incineration plants on BFR contamination in outdoor air and soil, but further investigation is required to confirm this.

The planetary atmospheric and surface environments that planetary probes, landers and rovers may encounter cannot be perfectly replicated in tests on Earth. The temperature, pressure and composition of atmospheric test environments for previous missions are reviewed, and the differences between the conditions used in tests and the actual conditions at the target body are discussed. Generally, it has been the practice to replicate only those few key parameters that determine the phenomena of interest, and the effects of gravity and of minor atmospheric constituents are rarely simulated explicitly. Typically tests have been performed in nitrogen atmospheres (rather than carbon dioxide for Mars and Venus) or Helium (instead of hydrogen for Jupiter): exceptions are a handful of specific tests where the composition was considered critical. In-flight thermal anomalies are generally attributable to differences between the static conditions in a test chamber and the dynamic environment of flight, rather than to the composition of test atmospheres.

There is a broad understanding of the influence of environmental factors on various aspects of normal mosquito behavior. How these external factors influence responses to repellent compounds is far less clear. The objective of this study was to investigate the effect of different daytime periods combining the normal circadian activity of a laboratory colony of Aedes aegypti (L.) with behavioral responses of mosquitoes exposed to three different compounds possessing repellent properties. Using an excito-repellency test chamber with different test designs (contact irritancy + repellency and noncontact repellency), female mosquitoes were exposed to each chemical or matching blank control during four different 3-h time intervals beginning 0600 to 1800 h. Mosquitoes showed more significant avoidance responses (escape movement away from the chemical) when exposed to either DEET or hairy basil during the afternoon periods. With deltamethrin, there was no significant difference in repellent escape movement during any period of testing. Escape activity with deltamethrin was significantly greater during all diurnal periods in contact tests compared to DEET and hairy basil. From this study, it was shown that time of diurnal testing can significantly influence behavioral responses of Ae. aegypti exposed to chemical-based repellents. Therefore, the assessment of chemicals (toxins, repellents, attractants) and must carefully consider time-of-test as a potential confounding factor during evaluation and comparisons.

Emissions and odors from different common indoor materials as interior surface materials and electric appliances were investigated within this study. The measurements were conducted in the glass test chamber under standardized conditions. An untrained sensory panel of 25 subjects perceived the quality of polluted air in the glass test chamber. The current study examined the emissions composition for six different types of indoor materials and six different types of electric appliances being used in open space offices. The results showed that the exposure response relationship varies for one of the tested materials compared with the others. The results confirmed that indoor pollution of tested materials and electric appliances are of equal value. The most acceptable results in each criterion (air acceptability (AA), odor intensity (OI) and total volatile compounds (TVOCs) concentration) were achieved for polyamide carpet (TVOCs 142 ug m3; AA-0.16; OI 1.77) and for notebook (T VOCs 119 ug m3; AA-0.33; OI 1.52). Unacceptable results in each criterion were achieved for OSB (TVOCs 1175 ug m3; AA-0.62; OI 3.21) and for the copier (TVOCs 562 ug m3; AA-0.77; OI 3.79). The results showed that the indoor pollution from both categories is equaled important. In terms of ensuring the indoor air quality, it is necessary to consider interior surface materials, as well as the expected electrical appliances.

Currently, comfort analyses of buildings equipped with thermoelectric air cooling or heating systems mainly focus on when occupants are in a wakeful state. In this study, both objective and subjective analyses of the sleeping behavior for fifteen (15) healthy occupants were conducted by exposing the occupants to two sleeping environments (i.e., test room equipped with the thermoelectric air duct cooling system (TE-AD) and naturally ventilated test room (NH)). The result shows that there were significant variations in the sleep satisfaction level in the test room with TE-AD and NH. Occupants felt more comfortable (5) and a slightly cooler thermal environment (3) while sleeping in the test room equipped with the TE-AD system. Their body movements, heart rate and sleeping stages shift from non-rapid eye movement (NREM) to rapid eye movement (REM) and then to the waking stage (WS), was less in test room with the TE-AD system as compared to NH. The occupants gave slightly hot (5) for indoor climatic ratings in NH room and felt a slightly uncomfortable (3) while sleeping. The PMV and PPD analyses showed that occupants were very sensitive to climatic conditions around bed and with slightly change in temperature (1.2 ± 0.4 °C) results in the shifting of sleeping stages. For the TE-AD room, the average occupant sleep onset latency was 19 ± 0.5 min, which is 20 ± 0.4 min lesser than NH room.

In the operation of the sodium-cooled fast reactor, the accident caused by the leakage and combustion of liquid sodium is common and frequent in sodium-related facilities. In this paper, an experiment Harbin Engineering University-Sodium Columnar Fire 4 (HEU-SCF4) is carried out to focus on the combustion characteristics in a discontinuous columnar flow. Liquid sodium (250°C) with the flux of about 1.0 m3/h was injected into a 7.9 m3 stainless steel cylindrical test chamber twice to shape the sodium fire in a columnar flow with discontinuous injections. The temperature, pressure data, and heat release rate in the test chamber were acquired and analyzed. It is found that each injection would cause a peak of space temperature, and it takes much shorter time to reach temperature peak in the second injection than the first injection. The peaks of pressure and heat release rate caused by the second injection are much higher than those caused by the first injection. This study is promising to evaluate t...

The purpose of this study was to investigate the effectiveness of idle reduction technologies (IRTs) in reducing driver exposure to diesel exhaust, and to study the cost effectiveness of these technologies. IRTs are devices that provide heating and cooling to the cabin of a truck without idling the truck engine. The focus was on diesel-powered IRTs (auxiliary power units and fuel-operated heaters), and their impact on particulate matter (PM2.5) exposure of drivers sleeping or resting in the truck’s cabin. The focus was on diesel-powered IRTs as these devices generate their own emissions, potentially exacerbating in-cab exposure levels. The project involved initial field data collection at truck stops in the states of Georgia, Texas and California. This was followed by laboratory testing in an environmentally controlled test chamber on a sample of trucks, with and without the use of IRTs. The study findings showed that the use of IRTs resulted in a significant reduction of PM2.5 levels in the truck cabin when compared with the baseline scenario of a truck parked with the engine off and the doors and windows closed. Idling the truck engine and running the air conditioning system was also found to reduce in-cabin PM2.5 levels relative to the baseline. The study supports the premise that IRTs reduce driver exposure to diesel exhaust. Additionally, it was found that these devices are cost effective in that they all have payback periods of less than five years, making them viable alternatives to idling the truck engine during long-duration rest periods.

Little information is available on the performance of commercially available indoor passive panel technologies (IPPT) based on sorptive and photocatalytic processes. In this paper, we studied 8 sorptive- and 3 photocatalytic oxidation (PCO)-based materials using controlled test chamber experiments. Four reference samples were used as controls. Sorptive-based samples were challenged with toluene and formaldehyde at 100 μg/m3 to determine their removal rates. PCO-based samples were challenged with only toluene at 100 μg/m3 to determine its removal rate and ozone and carbonyl by-product formations. Removal performance variations were wide across all IPPT samples although for every IPPT sample, its removal rate was better than its conventional counterpart. Most sorptive-based IPPT samples were not equally effective in removing toluene and formaldehyde. Painting on IPPT gypsum boards reduced their removal performance down to levels comparable to those of conventional gypsum boards. Toluene removal using PCO-based IPPTs were dependent on light used: only two PCO IPPTs are capable of performing under visible light. All PCO-based IPPTs generate ozone and carbonyls as by-products releasing up to 1.0 mg/h and 3.2 mg/h of ozone and formaldehyde respectively. This is a concern as exposures to ozone and formaldehyde have been known to be associated with negative health outcomes.

With reference to the international standard ISO16000-9 and the national standard GB/T 31106-14, this paper has chosen leather seats as the research object in order to study the emission of volatile organic compounds (VOCs) and total volatile organic compound (TVOC). The test results show that about 21 species of VOCs released from the leather seats were measured, including several types of aldehydes, ketones, aromatic hydrocarbon ,hydrocarbon, lipids and so on.This paper analysis the possible sources of volatile organic compounds in leather seats as well.

In this paper, the dynamic behaviour of aluminium foam sandwich plates (AFSPs) under impact loadings at low temperature was experimentally investigated. The impact force and the deformation as well as the energy absorption performances of AFSPs at room temperature and low temperature were obtained by using the drop tower INSTRON 9350 with thermostatic test chamber. The effects of impact energies and repeated impact loadings on the dynamic behaviour of AFSPs at room temperature (20 °C) and low temperature (−60 °C) were further examined. Experimental results showed that with the increase of the impact energy, the effect of low temperature on the dynamic behaviour of AFSPs under single impact loadings was enhanced gradually, the deflections of AFSPs at low temperature were smaller compared to that at room temperature, as a result of the increase in the yield stress of aluminum foam and mild steel at low temperature. Under repeated impact loadings, the deflections and absorbed energies of AFSPs at low temperature were smaller than those at room temperature. With the increase of impact number, the effect of low temperature on dynamic behaviour of AFSPs became much more significant.

The shock-induced reaction behavior of ZrCuNiAl bulk metallic glass (BMG) was investigated by means of a modified quasi-sealed test chamber. A series of quasi-sealed chamber impact experiments were conducted through launching ZrCuNiAl BMG fragments into the test chamber. It was shown that the semi-sphere shape of the modified quasi-sealed chamber suits the expanding manner of reactions. The results demonstrated that the BMG fragments underwent chemical reaction when impacted onto steel target. The energy released by reaction led to significant pressure rise inside the quasi-sealed chamber. It was shown that the amount of energy increased with the increasing of impact velocity. A relationship between the overpressure inside the chamber and the released chemical energy was derived to analyze the effect quantitatively.

The impact and penetration of a projectile in a particle-laden space, which are expected to have frequently occurred during the formation of the solar system and will occur in the case of an impact probe for future planetary exploration, were experimentally simulated by using the ballistic range. A two-dimensional sheet made from small glass beads or emery powder was formed by the free-falling device through a long slit in the test chamber evacuated down to about 35 Pa. A polycarbonate projectile of a hemi-sphere-cylinder or sphere shape with the mass and diameter about 4 g and 25 mm, respectively, was launched at the velocity up to 430 m/s, and the phenomena were observed by the high-speed camera at 20,000 fps. From a series of images, the bow-shock-wave-like laterally facing U-shaped pattern over the projectile and the absence of particles in the trail behind it were clearly seen. At the impact of the particles on the projectile surface, fine grains were formed due to the destructive collision and injected outward from the projectile. The images obtained by different lighting methods including the laser light sheet were compared. The effects of the particle diameter, its material and the impact velocity were also investigated.