Climate Chamber Tests Research Articles

Thermally Coupled NTC Chip Thermistors: Their Properties and Applications.

Negative temperature coefficient (NTC) chip thermistors were thermally coupled to form a novel device (TCCT) aimed for application in microelectronics. It consists of two NTC chip thermistors Th1 and Th2, which are small in size (0603) and power (1/10 W). They are in thermal junction, but concurrently they are electrically isolated. The first thermistor Th1 generates heat as a self-heating component at a constant supply voltage U (input thermistor), while the second thermistor Th2 receives heat as a passive component (output thermistor). The temperature dependence R(T) of NTC chip thermistors was measured in the climatic test chamber, and the exponential factor B10/30 of thermistor resistance was determined. After that, a self-heating current I1 of the input thermistor was measured vs. supply voltage U and ambient temperature Ta as a parameter. Input resistance R1 was determined as a ratio of U and I1 while output thermistor resistance R2 was measured by a multimeter concurrently with the current I1. Temperatures T1 and T2 of both thermistors were determined using the Steinhart-Hart equation. Heat transfer, thermal response, stability, and inaccuracy were analyzed. The application of thermally coupled NTC chip thermistors is expected in microelectronics for the input to output electrical decoupling/thermal coupling of slow changeable signals.

Moisture buffer value for hygroscopic materials with different thickness

Moisture buffering is the capacity of hygroscopic building materials or adsorbents to mitigate the humidity fluctuations in the indoor environment through the adsorption/desorption phenomenon. NORDTEST proposed the moisture buffer value to quantitively characterize the moisture buffering capacity of porous materials. Materials with high moisture buffer values have a higher ability to passively control indoor humidity conditions and thus reduce building energy consumption and improve indoor thermal comfort. However, the ideal moisture buffer value theory is based on the assumption that the thickness of the studied materials should exceed the penetration depth of that material. This assumption significantly limits the application of moisture buffer value theory to thin-layer materials, such as textiles, desiccant coating, wallpaper, wood wall panels, etc, which represent a large proportion of moisture buffering in the built environment. In this study, we developed a new numerical model to calculate moisture buffer values for hygroscopic materials with different thicknesses. Experimental measurements were also carried out to validate the solutions. The moisture buffer value of a new kind of desiccant (metal-organic frameworks) under different thicknesses were measured by climatic chamber tests. Simulated results showed agreement with both the measurements and theory. The results indicate that the new moisture buffer value model can be used to find the optimal thickness of desiccant coating or hygroscopic materials for autonomous indoor humidity control.

Hygrothermal aging effects on fiber-metal-laminates with engineered interfaces

This short work is to communicate the influence of hygrothermal aging on the mechanical performances of fiber-metal-laminates (FMLs) with various ingenious metal surface treatments, namely, nano-scale electrochemical sculpture (NES), the conventional surface polishing (PS) and NaTESi anodizing (NaTESi). The specimens with different edge conditions were prepared using milling or wire-electrode cutting and subjected to hygrothermal aging treatment in a climatic test chamber at 60 °C and 96% relative humidity. Interlaminar shear and flexural testing results showed that the wire-electrode cutting method produced edges with exposed fibers and spalling resin after hygrothermal aging, while the milling cutting method resulted in edges with a micro-porous and defective surface, but without exposing fibers or spalling resin. The degree of reduction in interlaminar shear strength (ILSS) and flexural strength varied depending on the surface treatments and machining methods used. After undergoing hygrothermal aging, the wire-electrode cutting method causes a greater decrease in ILSS compared to the milling cutting method. This reduction is particularly pronounced in specimens with weaker interfacial bonding strength, in which the ILSS of wire-electrode cut FMLs-PS decreased by 32.5%, while that of FMLs-NES decreased by 17.8%.

Influence of Undergarments on the Comfort Level of Scoliosis Brace Wearers.

Bracing has proven to be an effective method for the conventional treatment of scoliosis in young people. A brace, a therapeutic device, covers the upper body and promotes healing by applying pressure to specific areas. However, wearing a scoliosis brace negatively affects the user's thermo-physiological well-being and often leads to discomfort. In this study, we investigated the influence of T-shirts as an undergarment on the thermo-physiological well-being of the brace wearer. For this purpose, we performed a comparative analysis of six T-shirts made from different special knitted fabrics. We carried out wearing tests in a computer-controlled climate chamber according to a predetermined protocol. The test subject wore the orthopedic brace over the different T-shirts at three different temperatures. The results indicate that the knitted fabrics of undergarments and environmental conditions considerably impact the wearer's thermo-physiological comfort. In the tests, the T-shirts made from the selected functional fabrics performed very well. The T-shirt made from the classic cotton fabric containing elastane yarn also performed well and was the most environmentally friendly. Currently, due to its lower price and easier availability, this cotton T-shirt can be recommended for wearing under a scoliosis brace.

Durability of antireflective SiO2 coatings with closed pore structure

The use of antireflective coatings to increase the transmittance of the cover glass is a central aspect of achieving high efficiencies for solar collectors and photovoltaics alike. Considering an expected lifetime of 20–30 years for solar energy installations, the durability of the antireflective surfaces is essential. Here, a novel antireflective SiO2 coating with a hexagonally ordered closed pore structure, produced with an aerosol-based sol-gel method is benchmarked against two commercial coatings; produced with acid etching and sol-gel roll coating. The optical and mechanical properties together with contact angle characteristics were evaluated before and after various durability tests, including climate chamber tests, outdoor exposure, and abrasion. Compared to the commercial antireflective coatings with open pore structures, the novel coating performed in parity, or better, in all tests. Based on the results of humidity freeze and industrial climate chamber tests, it appears that the coating with closed pore structure has a better ability to prevent water adsorption. Additionally, the closed pore structure of the coating seems to minimize the accumulation of dirt and deposits. The abrasion and cleanability test further confirm the advantages of a closed pore structure, showcasing the coating's mechanical durability. While the coatings exhibit similar hardness and reduced elastic modulus, the closed pore coating proves to be even harder after undergoing the industrial climate chamber test, but also slightly more brittle, as indicated by the probability of crack initiation. In summary the closed pore structure is well suited for tempered and arid climates, making it a truly competitive alternative to existing antireflective coatings.

Evaluation of polymer-based eccentric FBG bending sensor for humidity, strain, temperature and torsion

We analyse and evaluate the sensitivity and robustness of an eccentric fiber Bragg grating sensor micro-structured into a polymer optical fiber under different relative humidity, temperature, strain and torsion conditions. Relative humidity and temperature conditions are established with a climate test chamber and prepared salt solutions. Though made of polymer, the cross-sensitivity of the sensor to relative humidity is low, enabling usage in rapidly changing environment applications, e.g., for movement detecting gloves or in vehicles, but also in high moisture situations. We find a linear dependence on temperature, so that either bending or temperature can be measured separately from each other. After rotation of one end, the sensor measures torsion by observing the light intensity and the change of the full width at half maximum. Strain measurement shows multiple elastic strain regions before final plastic deformations occur. In the next step, the flexible sensor system will be implemented in a sensor glove to monitor finger movement and detect different hand gestures.

Experimental research on formaldehyde emission characteristics from glubam by climate chamber test

Glued laminated bamboo (glubam) is a type of bamboo-based lamina, and manufactured by pressure lamination of phenol-formaldehyde saturated bamboo strips under elevated temperature. Estimating, controlling, and limiting the formaldehyde release from glubam are important issues in indoor air quality of building with glubam. This study investigates formaldehyde emission characteristics from two types of glubam under different conditions including temperature, relative humidity, edge treatment, and surface covering material. A series of formaldehyde concentration tests were performed using 1 m3 climate chamber. The results indicate that the peak values of the formaldehyde concentration of glubam specimens under all testing conditions are lower than 0.124 mg/m3, and thus can be classified as Class E1 according to EN 13986. An analysis model was provided to estimate formaldehyde release based on the test data and a first-order decay model. Initial formaldehyde emission rate E0 and decay rate constant k in the proposed model was utilized for comparison and analysis of the experimental parameters. This investigation reveals that the temperature and relative humidity have significant influence on the formaldehyde emission characteristics of glubam boards. Sealing cutting edges and covering surface layer of the samples can significantly reduce the releasing rate and amount of formaldehyde from glubam.

Investigation of microscopic creep and shrinkage deformations of cement paste assisted by digital image correlation technique

New in-situ microscopic mechanical tests in Environmental SEM (ESEM) and climatic chamber (CC), assisted by Digital Image Correlation (DIC) technique, have been developed. The developed testing frameworks speed up the drying duration at least 200 times compared to classical test methods. We mitigate the risk of cracking to focus on the intrinsic drying creep and shrinkage. Free drying shrinkage is assessed at a micro-scale and exhibits a high correlation with the mass loss for relative humidity above 60% relative humidity (RH). We observe a water cavitation effect between 50–60% (RH). Although the drying conditions in ESEM occur at low pressure compared to ambient air-drying conditions in a climatic chamber, the shrinkage deformations at equilibrium at 20% RH are quite the same. The evolution of desiccation creep with drying shrinkage is bilinear in uniaxial and linear under biaxial compression. The drying creep Poisson’s ratio is negative, between −0.1 and 0.

Responses of soccer players performing repeated maximal efforts in simulated conditions of the FIFA World Cup Qatar 2022: A holistic approach.

This study aimed to assess the capacity for repeated maximal effort (RME) of soccer players in the thermo-natural conditions (NC) and in simulated conditions for the 2022 FIFA World Cup in Qatar (QSC). Twenty-four semi-professional soccer players participated in the study. The exercise test consisted of ten 6-second maximal efforts on a cycloergometer. A 90-second passive rest interval was used. The test was performed in a Weiss Technik WK-26 climate test chamber in two different conditions: 1) thermo-neutral conditions (NC-20.5°C; 58.7% humidity); and 2) simulated conditions for the 2022 World Cup in Qatar (QSC-28.5 ± 1.92°C; 58.7 ± 8.64% humidity). Power-related, physiological, psychomotor, blood, and electrolyte variables were recorded. Results showed that (1) players achieved higher peak power (max 1607,46 ± 192,70 [W] - 3rd rep), needed less time to peak power (min 0,95 ± 0,27 [s] - 3rd rep), and had a higher fatigue slope (max 218,67 ± 59,64 [W/sek] - 7th rep) in QSC than in NC (in each repetition of study protocol); (2) between the 1st repetition and subsequent repetitions a number of significants in among physiological, blood-related, and electrolyte variables were noted, but their direction was similar in both simulated conditions (e.g. V'O2/kg 37,59 ± 3,96 vs 37,95 ± 3,17 [ml/min/kg] - 3rd rep, LAC 13,16 ± 2,61 vs 14,18 ± 3,13 [mg/dl] - 10th rep or K 4,54 ± 0,29 vs 4,79 ± 0,36 [mmol/l] - 2nd rep when compare QCS and NC respectively); (3) an 8°C of temperature difference between the climatic conditions did not significantly affect the soccer players' physical and physiological responses in RME. The study results can be used in the design of training programs aimed to increase players' physiological adaptations by simulating soccer-specific conditions of play in terms of anaerobic capacity, in particular, repetitive maximal efforts. These findings will be useful during the upcoming 2022 World Cup in Qatar and in locations where high ambient temperatures are customary.

Experimental examination of heat transfer coefficients in hydronic radiant wall cooling systems

Radiant heated and cooled wall systems may offer benefits like building retrofitability, architectural flexibility, a comfortable thermal atmosphere, and compatibility with alternative energy sources. In certain situations, radiant wall systems are preferable to floor and ceiling systems due to their benefits. In this study, a set of tests were performed in order to assess the heat transfer features of the hydronic radiant wall cooling system. A climatic test chamber was constructed for this objective, and convection, radiation, and total heat transfer coefficients (HTCs) were evaluated and analyzed. For the purpose of calculating the HTCs, experiments were conducted at various supplied water temperatures. The HTCs were then estimated using the corresponding characteristic temperature differences. The total, radiation, and convection HTCs for the cooled radiant wall were found to have estimated mean values of 8.25, 5.52, and 2.41 W m−2.K−1, respectively. Radiation contributes to around 70% of the overall heat transfer on average. Additionally, two different radiant panel arrangements were tested to examine how the thermal conductive layer influenced the thermal performance of the cooled radiant panels. The cooling capacity of the panel with an aluminum conductive layer is about 21% more than that of the traditional panel.

First report of Sclerotinia sclerotiorum on watercress (Nasturtium officinale) in aquaponic system in Hungary.

Watercress (Nasturtium officinale) is an aquatic dicotyledonous vegetable belonging to Brassicaceae (Aiton 1812). Watercress was grown in an aquaponic system on fired clay ball medium at the Aquaponic Research Station of the University of Debrecen, in the city of Debrecen (Hungary). During January 2020, 3-month-old plants showed symptoms in aquaponic cultivation. A visual survey showed 30% of plants with symptoms. Leaves and stems withered and showed white cotton-like mycelium. Mycelia from infected plants were placed on potato dextrose agar (PDA) and incubated at 25°C for seven days. Single hyphal tips were transferred to produce a pure culture. All ten fungal isolates showed similar morphological characteristics on PDA. Colonies consisted of white mycelia after three days and globoid to irregular and black 2.5 to 7 (average, 3) mm (n = 100 from ten plates) sclerotia formed ten days later, which are the typical morphological features of Sclerotinia sclerotiorum (Mordue et al. 1976). Molecular identification was performed with one of the ten isolates (Scl_B). Mycelia were grown in 250 ml of potato dextrose broth in a rotary shaker at 175 rpm at 24°C for six days. DNA was extracted from mycelium using a Nucleospin plant II (Macherey-Nagel, Germany) according to the manufacturer's protocol. PCR amplification (Kim et al. 2014) was performed with primers ITS1/ITS4 for the internal transcribed spacer region (White et al. 1990) on a Primus 96 thermal cycler (MWG Biotech, Germany). Specific polymerase chain reaction was performed with primers SSasprF/SSasprR (Abd-Elmagid et al. 2013). PCR products were sequenced by Microsynth Austria GmbH. NCBI BLAST analysis of the 440-bp ITS sequence (Genbank MW012403.1) showed 100% identity with the sequence of S. sclerotiorum (MT177267.1, etc.). The 170-bp specific gene sequence (Genbank MW959042.1) had a 100% similarity to hypothetical proteins (Genbank MK028159.1), with a 99.4% similarity to a portion of the S. sclerotiorum aspartyl protease gene (AF271387.1). Pathogenicity tests were carried out by inoculating surface-disinfested, 30-day-old watercress plants in plastic pots (15x15x12 cm). In three repeated experiments 90 watercress plants were measured. 15 plants (one plant per pot) were planted into the five-times autoclaved substrate (Biorgmix: pH 6.1±0.5%, N:1.5%, P2O5:0.7%, K2O:0.5%, organic matter content:50%) and inoculated by ten wheat kernels that were colonized by S. sclerotiorum (Scl_B) (Garibaldi et al. 2019). 15 plants were planted into the substrate with ten non-inoculated kernels as a control. Plants were kept in an MLR-352 climatic test chamber (PHCbi, Japan) at 21 ± 1°C for 12 hr light:dark cycle. On the first day of the experiment complex nutrient solution (Tek-Land: N:5%, P2O5:5%, K2O:5%, B:0.01%, Cu:0,01%, Mn:0.02%, Mo:0.002%, Zn:0.016%) was used, then autoclaved water daily. Eight days later white mycelium appeared on every inoculated plant and five days later dark sclerotia formed on the stems. Based on the morphological characteristics the re-isolated pathogen was S. sclerotiorum. Similar results were detected in three repeated experiments with white mold fungus being reisolated from all 45 infected watercress plants. The 45 non-inoculated plants did not show any symptoms and any diseases. This pathogen has already been reported on watercress in the field (Farr et al. 1989; Boland and Hall 1994; Garibaldi et al. 2019). This is the first reported case of white mold on watercress in aquaponic system in Hungary.

Effect of ambient air relative humidity on the triboelectric properties of Polypropylene and Polyvinyl Chloride slabs

The humidity of ambient air has always been known to be a major factor in the triboelectric charging of polymers. A study on the influence of this factor was conducted in a climatic test chamber on square-cut Polypropylene (PP) and Polyvinyl Chloride (PVC) plates of dimensions (110 mm × 110 mm x 4.5 mm) rubbed with Aluminum (Al) samples of dimensions (100 mm × 15 mm x 5 mm). The samples were left at least 12 h in the climatic test chamber at fixed temperature (25 °C) and three different values of air relative humidity (20%, 40% and 80%), then rubbed together in a triboelectric charging test bench. The tribocharged PP and PVC samples were then placed under an electrostatic probe to measure the electric potential generated on the surface of the sample. The results of the experiments show that the sign of the tribocharge reverses when the two polymers are exposed to low or high ambient humidity.

The Behavior of Different Varnishes Applied to Graphic Artworks: Comparison Using a Methodological Protocol

ABSTRACT This paper presents the results of a series of tests – using a recently-published set of methodological guidelines referred to here as the Protocol – on varnishes traditionally used in the protection and enhancement of graphic artworks. The aim of the research was to study the characteristics of different varnishes when they are applied to a graphic artwork and to analyze their behavior when exposed to conditions that cause alterations, be these natural factors, accidental, or the result of a conservation intervention. Lastly, the study sought to determine whether each varnish was suitable for conservation purposes. Five varnishes were selected for the study: egg white, gum arabic, shellac, rosin, and dammar. Paper test samples were used to study the characteristics of the recently applied varnishes: dimensions, weight, thickness, color, brightness/gloss, pH, surface appearance, drying time, degree of absorption by the substrate, and adhesion to the substrate. The behavior of varnishes was studied via a series of tests that recreated adverse conditions (humidity, light, and temperature). These tested for resistance to ambient humidity, immersion in water, dry-heat aging, and aging in a climate test chamber. After applying the Protocol it was concluded that the varnishes most resistant to different alteration factors are gum arabic and dammar resin. By contrast, shellac and rosin are the most susceptible to alterations, which precludes their use as a conservation material. As well as indicating the varnishes that present the minimum interaction with the substrate and the greatest long-term durability, the results of this research also provide a useful guide to the behavior of these varnishes for their use in preventive conservation.

The effects of firefighting boots and personal protective equipment load on foot thermal comfort

Maintaining foot comfort is important as it influences the overall comfort of the human body. Shoe microclimate and foot skin temperature have been suggested to contribute to the thermal sensation of the foot. Considering the thermal environment and personal protective equipment (PPE) used for structural and proximity firefighting, climatic chamber tests with 13 male participants were conducted during standing and walking. Four test conditions – unloaded with training shoes, loaded with training shoes, unloaded with firefighting boots, and loaded with firefighting boots – were designed to investigate the effects of firefighting boots and PPE load on the thermal comfort of the human foot. Physiological variables of in-shoe and foot skin temperature at the whole and local regions of the foot were measured and subjective responses were gathered using psychological scales. The results showed that wearing firefighting boots may elevate the thermal sensation of wearers. The PPE load increased the in-shoe and foot skin temperature as well as subjective ratings. Subjective sensations of the foot were strongly correlated with in-shoe and skin temperature in the plantar regions. Correlation analysis of thermal sensation at the whole and local foot regions indicated that the sensation at the forefoot was closest to the whole foot, followed by the midfoot and heel. The findings address the relationship of physiological and subjective variables as well as the thermal sensation of whole and local foot regions, which can be considered for footwear design and thermal comfort prediction of the foot and whole body.

Sensitivity of rice to photooxidation associated with antioxidant enzyme activity and carbon assimilation

In this study, rice cultivar 8272 (yellowing leaves) was compared with cultivar 9311 (normal leaf color) to clarify the mechanism underlying the chlorosis. The 8272 leaf color was sensitive to intense sunlight accompanied by high temperatures, which induced the yellowing of leaves, whereas the 9311 leaf color was normal under the same growing conditions. A shading experiment in the field and an artificial climate chamber test revealed that the chlorosis of 8272 leaves was due to high-intensity light, rather than high temperatures. Analyses of chlorophyll fluorescence parameters indicated that the photosystem II (PSII) reaction center activity of 8272N (grown under natural high light conditions) was significantly lower than that of 8272S (under shade), with the electron transfer significantly inhibited. The H2O2, O2.−, and malondialdehyde (MDA) contents increased sharply in 8272N, and the antioxidant enzymes were also activated. A comparison of the enriched KEGG pathways among the differentially expressed genes (DEGs) between 8272 and 9311 indicated genes related to abiotic stress tolerance were highly expressed in 8272N. In contrast, the expression levels of the key genes in the carbon assimilation metabolic pathway were significantly lower in 8272N than in 9311N. A qRT-PCR analysis confirmed the results of the RNA-seq and antioxidant enzyme activity analyses. Thus, the chlorosis of 8272 leaves in response to intense light may be associated with the mechanisms contributing to the photosynthetic control of electron transport via carbon assimilation in leaves.

Fibre Optic FBG Sensors for Monitoring of the Temperature of the Building Envelope.

Standard sensors for the measurement and monitoring of temperature in civil structures are liable to mechanical damage and electromagnetic interference. A system of purpose-designed fibre optic FBG sensors offers a more suitable and reliable solution—the sensors can be directly integrated with the load-bearing structure during construction, it is possible to create a network of fibre optic sensors to ensure not only temperature measurements but also measurements of strain and of the moisture content in the building envelope. The paper describes the results of temperature measurements of a building 2-layer wall using optical fibre Bragg grating (FBG) sensors and of a three-layer wall using equivalent classical temperature sensors. The testing results can be transmitted remotely. In the first stage, the sensors were tested in a climatic test chamber to determine their characteristics. The paper describes test results of temperature measurements carried out in the winter season for two multilayer external walls of a building in relation to the environmental conditions recorded at that time, i.e., outdoor temperature, relative humidity, and wind speed. Cases are considered with the biggest difference in the level of the relative humidity of air recorded in the observation period. It is found that there is greater convergence between the theoretical and the real temperature distribution in the wall for high levels (~84%) of the outdoor air relative humidity, whereas at the humidity level of ~49%, the difference between theoretical and real temperature histories is substantial and totals up to 20%. A correction factor is proposed for the theoretical temperature distribution.

Study of an Mg90Y7Zn3 alloy (WZ73) in sodium chloride solution — An analysis by correlated polarization and climate chamber testing

AbstractIn the present work, the corrosion behavior of a twin‐roll cast WZ73 magnesium alloy is investigated by potentiodynamic polarization and climate chamber tests in different sodium chloride solutions. The corrosion parameters Ecorr and jcorr are extracted from the polarization curves, and the critical concentration for the initiation of pitting corrosion is thus identified. The critical concentration for the initiation of pitting is confirmed by means of climate chamber tests. As a consequence, the WZ73 magnesium alloy is found to be highly susceptible to pitting corrosion in sodium chloride solutions of concentrations higher than 10−4 mol/L. Moreover, when the NaCl concentration increases, the corrosion mechanism changes from pitting to filiform corrosion, which is attributed to micro‐galvanic effects. At low NaCl concentrations, the corrosion attack remains localized. When the NaCl concentration increases, pitting occurs and, in addition to the pits that form, micro‐galvanic corrosion leads to filiform corrosion attack. This is caused by the electrochemical potential of the long period stacking ordered phase, which is higher than that of the α‐Mg matrix. Consequently, the corrosion attack is focused on the phase boundary between the α‐matrix and LPSO phases.

Experimental investigation of a high efficiency electric heater and dehumidifier prototype unit

In this paper the principle of operation and preliminary laboratory measurements of a prototype of a high-efficiency electrical air heater unit is presented. Unlike conventional heaters, which apply Joule-heat formed by electrical resistance, the developed device uses thermoelectric modules for heating ambient air. Just like in case of resistance heaters, most of the heat is produced as a result of the internal ohmic resistance of the thermoelectric module (resistance heating), however, in case of appropriate air conditions our device is capable of transforming the latent heat of the air moisture into heat energy. In case of condensation mode, some of the moisture condensates on the cold side of the module while its latent heat is transferred to the hot side of the module where it heats the dried air. In this mode, the heating efficiency of the device (e.g., the ratio of the heat added to air and the consumed electricity) is over unity. Following the idea and basic equations of the operation of this device, the results of the laboratory measurements in a climate test chamber is presented.

Исследования боевой одежды пожарного, предназначенной для эксплуатации в условиях Крайнего Севера и Арктической зоны

Methodological base was developed for assessing the quality of firefighter - saviour combat clothing for use in the Arctic zone. It consists of a mathematical model for calculating the thermal state of special combat clothing in the «man — firefighter’s combat clothing — working environment» system and a chamber climate test methodology with the participation of testers-volunteers. The results of some calculations of the firefighter’s combat clothing thermodynamic state under the climatic factors exposure (negative values of the ambient temperature, wind load), and the fire thermal factors exposure are presented. Calculations were made based on the time and tasks performed, on the basis of actual working conditions of the firefighter. According to the calculation results we can conclude that in the considered range of variation of the environmental parameters of the working environment in the climatic conditions of the Arctic zone, the time of protective action of a multilayer stack of materials and tissues of the firefighter’s combat clothing is determined by the time of reaching of the skin surface limit temperature cooling in the region of the unheated structural elements. In this case the heat flux is not a determining factor. Verification of the model is carried out by comparing the results of experimental measurements and data obtained by calculation. The climate chamber test methodology includes registration in the process of tests of the firefighter’s combat clothing under-suit space thermodynamic parameters and the tester physiological parameters using both special sensors and displaying the results on a computer multiplier in real time mode. In addition, a visual assessment of the firefighter’s combat clothing technical condition at the end of the tests is carried out. Based on the results of the performed studies of the specific firefighter’s combat clothing samples it can be concluded that the developed methodological base allows to perform the objective assessment of the Arctic version of the firefighter’s combat clothing according to the application indicators that determine the quality of the product, and can be used to assess the quality of other personal protective equipment of a firefighter.

Effect of Some Chemical Treatments on Dormancy Breaking and Germination of Black Elderberry (Sambucus nigra L.) Seeds

Çoğu bitki türünde tohumda dormansinin kırılması ve çimlenmenin teşvik edilmesi amacıyla çok çeşitli fiziksel ve kimyasal uygulamalara yaygın olarak başvurulmaktadır. Bu tez çalışması konsantre nitrik asit (%68), konsantre sülfürik asit (%98) ve gibberellik asidin siyah mürver (Sambucus nigra L.) tohumlarında dormansinin kırılması ve çimlenmenin teşvik edilmesi üzerine etkisini belirlemek amacıyla yürütülmüştür. Doğadan toplanan siyah mürver tohumları farkı sürelerde (0, 15, 30, 60 ve 90 dakika) sülfürik ve nitrik asitte bekletildikten sonra farklı dozlarda (0, 500, 1000 ve 2000 ppm) gibberellik asit çözeltisinde 24 saat tutulmuşlardır. Siyah mürver tohumları iklim odasında çimlendirme denemesine alınmış ve çimlenme oranı, kökçük ve sürgün uzunluk ve ağırlıkları belirlenmiştir. Siyah mürver tohumlarının 15 dakikadan daha uzun süre derişik sülfürik asitte bekletilmesiyle çimlenme oranı ve fide gelişimi çok büyük ölçüde gerilemiştir. Siyah mürver tohumlarının konsantre nitrik asitle muamele edilmesi kontrol tohumlarına göre çimlenmeyi ve fide gelişimini şiddetli derecede azaltmıştır. Gibberellik asit uygulaması nitrik asitle ön muameleye tabii tutulmuş siyah mürver tohumlarında hiçbir olumlu etki yapmamıştır. Ancak, 15 dakika sülfürik asitte tutulan siyah mürver tohumları 500 ppm gibberellik asit çözeltisinde 24 saat bekletilince %100 çimlenme oranına ulaşılmış ve fide gelişimi artmıştır. Bu bulgular siyah mürver tohumlarında fiziksel ve fizyolojik dormansinin birlikte etkili (birleşik dormansi) olduğunu ifade etmektedir. Bu çalışmanın sonuçlarına göre, siyah mürverde dormansinin kırılması ve çimlenmenin teşvik edilmesi açısından tohumların önce 15 dakika derişik sülfürik asitte tutulması ve daha sonra 24 saat süreyle 500 ppm gibberellik asit çözeltisinde bekletilmesi önerilebilir.