Constant Humidity Research Articles

Effects of temperature on bacterial microbiome composition in Ixodes scapularis ticks.

Ixodes scapularis, the blacklegged deer tick, is the principal vector of Lyme disease in North America. Environmental factors are known to influence regional and seasonal incidence of Lyme disease and possibly the endemicity of the disease to the northeastern and upper mid‐western regions of the United States. With a goal to understand the impact of environmental temperature on microbial communities within the tick, we investigated the bacterial microbiome of colony‐reared I. scapularis ticks statically incubated at different temperatures (4, 20, 30, and 37°C) at a constant humidity in a controlled laboratory setting by comparison of sequenced amplicons of the bacterial 16S V4 rRNA gene to that of the untreated baseline controls. The microbiomes of colony‐reared I. scapularis males were distinct than that of females, which were entirely dominated by Rickettsia. In silico removal of Rickettsia sequences from female data revealed the underlying bacterial community, which is consistent in complexity with those seen among male ticks. The bacterial community composition of these ticks changes upon incubation at 30°C for a week and 37°C for more than 5 days. Moreover, the male ticks incubated at 30 and 37°C exhibited significantly different bacterial diversity compared to the initial baseline microbiome, and the change in bacterial diversity was dependent upon duration of exposure. Rickettsia‐free data revealed a significantly different bacterial diversity in female ticks incubated at 37°C compared to that of 4 and 20°C treatments. These results provide experimental evidence that environmental temperature can impact the tick bacterial microbiome in a laboratory setting.

Effect of surface treatment of cellulose fiber (CF) on durability of PLA/CF bio-composites

Bio-composites made of polylactic acid (PLA) matrix reinforced with cellulose fibers (CF) were prepared using a twin-screw extruder and injection molding. The CFs were coated with epoxy-based surface treatment agents. Accelerated degradation tests were carried out on these PLA/CF composites at high temperatures (60 °C) or at constant temperature and constant humidity (60 °C/70% RH), and the higher-order structure changes and degradation characteristics of the molded products were evaluated. In the accelerated degradation test at 60 °C, the thermal and mechanical properties of PLA/CF composites showed no degradation, whereas at 60 °C and 70% RH, the melting point decreased ca. 25 °C and the storage modulus with increasing elapsed time decreased more than 50%. However, the thermal and mechanical properties of the PLA/CF composites treated with low-molecular-weight epoxy did not degrade, even at the high humidity of 70% RH. These results strongly suggest that the surface treatment agent not only improves interfacial adhesion between CF and PLA but also plays an important role in inhibiting degradation of the PLA matrix.

Study on Whisker Growth on Solder Joints—Part I: Study on Acceleration Test Method

The shift to lead-free tin-based solder in electronics has created a frequent observation of whisker growth from the plated tin surface. With an expectation that the tin whisker growth is not limited to the tin-plated surface, a three-year project of the Japan Electronics and Information Technology Industries Association (JEITA) for a study of whiskers on lead-free electronics was initiated in 2006, as one of the Strategic Core Technology Advancement Programs funded by Organization for Small and Medium Enterprises and Regional Innovation Japan. This paper reports one of the results of this JEITA project, relating to whisker formation from solder joints and its acceleration test methods. When samples were submitted to soldering process and then exposed to a high-temperature, high-humidity environment, a portion of the solder surface became unevenly corroded (oxidized). Tin in the area between corrosion received the stress and formed tin whiskers. Since soldering flux with bromine content exhibited a tendency to create whisker relatively fast, the influence of temperature and relative humidity was studied with this type of flux. The results from this test were analyzed for acceleration factors and found to have a good linearity in Arrhenius plotting with varied temperatures and a constant humidity, with a calculated activation energy of 0.84 eV. Combined with the test results with constant temperature and varied humidity, the same characteristic formulas for whisker growth from the plated tin surface under high temperature/humidity in the reports of the International Electronics Manufacturing Initiative were found to be also applicable to the cases of solder joints. The constants in the formulas, however, were found to be approximately equal to those for the humidity behavior of the conductive adhesive/tin plating interface or those found for electrochemical migration.

Detection of Surface Roughness Evolution of Carbon Steel Subjected to Outdoor Exposure and Constant Humidity Corrosion Tests

Detection of Surface Roughness Evolution of Carbon Steel Subjected to Outdoor Exposure and Constant Humidity Corrosion Tests

Influence of temperature and humidity on power frequency electric field intensity

ABSTRACTThe electric field intensity of substation is one of the main factors that influence the safety of power construction, but the strength of electric frequency electric field is affected by many factors. In order to study the effect of temperature and humidity on the electric field strength, the effect of temperature and humidity on the electric field strength was tested by a programmable constant temperature and humidity testing machine and the NARDA company's broadband field strength measuring instrument. The actual data were measured at the 220 kV voltage level of a substation in a place in Yuxi, Yunnan province. The experimental results show that when the temperature is constant, the electric field intensity becomes smaller as the humidity becomes larger. When the humidity is constant, as the temperature becomes larger, the electric field strength becomes smaller. And the influence of the temperature of the substation on the electric field intensity is greater than the influence of the humidity on the electric field strength.

Room-temperature growth (“farming”) and high-performance supercapacitor applications of highly crystalline CuO nanowires/graphene nanoplatelet nanopowders

We report a first-of-its-kind farming-like growth of nanopowders of CuO nanowires (NWs) via room-temperature thermal oxidation. Compared to conventional thermal annealing methods for producing copper oxide nanostructures, which require elevated temperatures (300–600 °C), the present method yields a large amount of highly crystalline CuO NW nanopowders at a much lower temperature (i.e., room temperature). Two-dimensional carbon nanostructures such as graphene nanoplatelets (GNPs) were used as supports for the growth of the CuO NWs. The GNPs were coated with Cu seed layers by the electroless plating method, which is suitable for mass production. After electroplating of Cu layers, the GNP supports were kept at room temperature and under constant humidity (50 or 60% relative humidity) for over 24 h, resulting in the dense wire-like morphology of copper oxide. Scanning electron microscopy, energy dispersive X-ray diffraction, X-ray diffraction, and Raman spectroscopy measurements revealed that the NWs consisted of highly crystalline monoclinic CuO. Once the NWs were formed, their morphology was stable for up to 168 h at room temperature. The as-prepared CuO nanopowders were tested as electrodes of electrochemical capacitors (or supercapacitors). In a three-electrode configuration, a working electrode made of CuO NWs exhibited an excellent mass-specific capacitance of 145 F g−1 at 5 mV s−1 in a 3 M KOH aqueous electrolyte. The growth of CuO nanopowders on GNPs illustrated in this study demonstrates a novel approach for the room-temperature synthesis of nanopowders, with promising applications in next-generation energy devices.

Moisture related elastic and viscoelastic behaviour of wood adhesives by means of in-situ nanoindentation

The adhered wood in multi-layered panels is subjected to different stress and strain states as a result of moisture induced swelling and shrinking. Consequently, it is expected that the adhesive layer has to compensate these stresses and responds beside elastic with viscoelastic deformation.To better understand the humidity dependent mechanical behaviour of commonly used cured wood adhesives, different adhesive systems that are currently used in furniture and flooring industry (emulsion polymer isocyanate EPI, polyvinyl acetate PVAc, urea formaldehyde UF and ultra-low emitting formaldehyde amino adhesive ULEF) were investigated by means of in-situ nanoindentation. Therefore, spruce (Picea abies) lamellas were adhesively bound under laboratory conditions. Micro-mechanical properties of adhesive layers, such as elastic modulus, creep and relaxation were investigated in quasi-static mode at constant temperature and different controlled humidity levels to monitor the mechanical response of the cured adhesive polymers in the corresponding ambient.As a general trend, all adhesives respond with decreasing elastic modulus to increased humidity. EPI revealed the most stable elastic behaviour to moisture. In contrast PVAc, UF and ULEF show significant differences with changing relative humidity levels. Lowest creep and relaxation was observed for UF and ULEF, followed by EPI. The most sensitive behaviour to moisture was observed for PVAc adhesive polymer.

Reducing the effect of dust deposition on the generating efficiency of solar PV modules by super-hydrophobic films

Dust deposition on photovoltaic (PV) modules is related to environmental and weather conditions and results in a reduction in power generation efficiency over time. The effects of films on the transmittance can be obtained by testing sample glasses coated with silicon and fluorine super-hydrophobic films with a spectrophotometer. Red soil particles with a diameter of 25 μm were selected to simulate the process of natural dust deposition on PV module samples, and an incubator of constant temperature and humidity was used to simulate the condensation process. PV module samples were irradiated by a solar simulator after the aforementioned simulation process, and the effects of different amounts of sediment in unit areas on the photovoltaic properties and spectral characteristics were determined. The experimental results indicate that the influence of dust on the power generation efficiency of PV modules coated with fluorine super-hydrophobic film is smaller than that for PV modules coated with silicon super-hydrophobic film and that the super-hydrophobic films can not only greatly reduce the dust accumulation on the surface of PV modules but also increase the generating efficiency.

705 A study about the importance of constant temperature and humidity system in analyzing skin barrier function

Background: Measurement of skin barrier function is easily affected by external environment such as temperature and humidity, especially in Korea where there are distinct four seasons. Objectives: This study was conducted to analyze the variation in measurement of skin barrier function with or without thermohygrostat conditioning in each season. Methods: The study voluntarily enrolled 10 healthy females whose age range from 28 to 34. Each subject was put into a room with a thermohygrostat facility. Transepidermal water loss (TEWL) and stratum corneum hydration (SCH) were measured before (uncontrolled value) and after operation of a thermohygrostat facility for 20 minutes (controlled value) in the middle of each season. Results: The measurements under controlled condition (TEWL 3.20±1.97, SCH 13.10±9.26) showed less variation compared with those under uncontrolled condition (TEWL 3.95±2.03, SCH 13.35±10.30), but there was no statistical significance (p>0.05). The difference between two conditions was statistically significant only in summer (TEWL p=0.009, SCH p=0.002). Conclusion: Although the study did not show statistical significance, the thermohygrostat could preserve skin barrier function from the external environment to some extent. Thus, it is regarded that a room equipped with a thermohygrostat could help measure more exact skin barrier function to exclude the influence of surrounding environment, especially in summer season.

Proline and ions accumulation in four Passiflora species under water-saline stress

Water-saline stress is one of the factors limiting growth and crop production, with the induction of morphological, structural and metabolic changes in higher plants. This study aimed to evaluate the response of four species with ten accessions of Passiflora to saline stress and drought stress, and the accumulation of proline and content of cationic macronutrients and their relationships with sodium. The plants were grown under controlled conditions for seven months, watered with nutrient solution with additions of NaCl (100 mM) to achieve the desired conductivities (1.5, 2.5, 4.0, and 5.5 dS m-1) and constant substrate humidity of 100%, 66% and 33%. The concentrations of Na+, K+, Ca++, Mg++ and proline in the leaves were determined. Proline accumulation increased in salinized plants, especially in young leaves. Proline increase was evident in accessions tolerant and moderately tolerant to salinity. These results indicate that tolerance to salinity and water stress in Passiflora relates to an improved ability to exclude sodium and greater ability to accumulate proline for osmotic adjustment. The increased salinity of the nutrient solution increased sodium contents, relations Na+/Ca++, Na+/Mg++, Na+/K+, and decreased Ca++, Mg++ and K+ levels, reflecting the nutritional imbalance caused by progressive saline stress.

Development and Activity Evaluation of Antialcoholism and Liver Detox Jiaosu

The antialcoholism and liver detox Jiaosu selected traditional Chinese medicine with antialcoholism effect, such as pueraria lobata, hawthorn, poria cocos as raw materials. After bioenzymatic hydrolysis, Lactobacillus rhamnosus 217-8 with high glutathione production was selected as fermentation strain. After fermentation, the Jiaosu was placed in a constant temperature and humidity environment, and the contents of flavonoids, puerarin, polyphenols and antioxidant capacity of Jiaosu were determined. The results showed that the content of puerarin was increased by 7 times, flavonoids increased by 3 times, amino acids increased by 6 times, polyphenols increased by 80mg/L, the antioxidant capacity increased by 92% of antialcoholism and liver detox Jiaosu compared with the raw material without enzymatic hydrolysis and fermentation. So we can draw the conclusion that the optimization and compatibility of radix puerariae, hawthorn, poria, through enzymatic hydrolysis and microbial transformation, not only the natural active ingredients intact and release, some of the macromolecular components can be transformed into small molecular components, which are beneficial to human absorption and metabolism, but also produce active secondary metabolites at the same time, and further improve the types and functions of active components in antialcoholism and liver detox Jiaosu. So, the antialcoholism and liver detox Jiaosu developed in this paper has an important potential in accelerating the circulation of tri-carboxylic acid and promoting the decomposition of acetaldehyde, improving the concentration of ethanol and triglyceride in the blood, and improving the anti - oxidation ability of the liver tissue.

Highly sensitive benzene detection with metal oxide semiconductor gas sensors – an inter-laboratory comparison

Abstract. For detection of benzene, a gas sensor system with metal oxide semiconductor (MOS) gas sensors using temperature-cycled operation (TCO) is presented. The system has been tested in two different laboratories at the concentration range from 0.5 up to 10 ppb. The system is equipped with three gas sensors and advanced temperature control and read-out electronics for the extraction of features from the TCO signals. A sensor model is used to describe the sensor response in dependence on the gas concentration. It is based on a linear differential surface reduction (DSR) at a low temperature phase, which is linked to an exponential growth of the sensor conductance. To compensate for cross interference to other gases, the DSR is measured at three different temperatures (200, 250, 300 ∘C) and the calculated features are put into a multilinear regression (partial least square regression – PLSR) for the quantification of benzene at both laboratories. In the tests with the first set-up, benzene was supplied in defined gas profiles in a continuous gas flow with variation of humidity and various interferents, e.g. toluene and carbon monoxide (CO). Depending on the gas background and interferents, the quantification accuracy is between ±0.2 and ±2 ppb. The second gas mixing system is based on a circulation of the carrier gas stream in a closed-loop control for the benzene concentration and other test gases based on continuously available reference measurements for benzene and other organic and inorganic compounds. In this system, a similar accuracy was achieved for low background contaminations and constant humidity; the benzene level could be quantified with an error of less than 0.5 ppb. The transfer of regression models for one laboratory to the other has been tested successfully.

Properties of Two-Variety Natural Luffa Sponge Columns as Potential Mattress Filling Materials.

Luffa sponge (LS) is a resourceful material with fibro-vascular reticulated structure and extremely high porosity, which make it a potential candidate for manufacturing light mattress. In this study, two types of LS columns, namely high-density (HD) and low-density (LD) columns, were investigated as materials for filling the mattress. The results showed that the compressive strength of HD LS columns was significantly greater than that of LD LS columns. However, the densification strains of the two types of LS column were both in the range of 0.6 to 0.7. Besides, HD LS columns separately pressed to the smooth plateau region and the initial densification region exhibited a partial recovery of instant height when they were unloaded, and then both of them showed no more than 4.2% of height recovery after being allowed to rest at a constant temperature and humidity for 24 h. In contrast, when LD LS columns were compressed to the smooth plateau region, the height recovery was less than 1.62% compared to when they were pressed to the initial densification region, and that was more than 15.62%. Similar to other plant fibers used as mattress fillers, the two types of LS columns also showed good water absorption capacity—both of them could absorb water from as much as 2.07 to 3.45 times their own weight. At the same time, the two types of LS columns also showed good water desorption. The water desorption ratio of HD and LD LS columns separately reached 76.86 and 91.44%, respectively, after being let rest at a constant temperature and humidity for 13 h.

Native oxide formation on pentagonal copper nanowires: A TEM study

Hydrothermally synthesized copper nanowires were allowed to oxidize in air at room temperature and 30% constant humidity for the period of 22 days. The growth of native oxide layer was followed up by high-resolution transmission electron microscopy and diffraction to reveal and understand the kinetics of the oxidation process. Copper oxides appear in the form of differently oriented crystalline phases around the metallic core as a shell-like layer (Cu2O) and as nanoscopic islands (CuO) on the top of that. Time dependent oxide thickness data suggests that oxidation follows the field-assisted growth model at the beginning of the process, as practically immediately an oxide layer of ∼2.8 nm thickness develops on the surface. However, after this initial rapid growth, the local field attenuates and the classical parabolic diffusion limited growth plays the main role in the oxidation. Because of the single crystal facets on the side surface of penta-twinned Cu nanowires, the oxidation rate in the diffusion limited regime is lower than in polycrystalline films.

Working Conditions on the Afterglow Characteristics of Rare-earth Luminous Fibers

To test and clarify the stability of afterglow performance of luminescent fibers can accelerate the step of the commercialized application on luminescent textiles. This work investigated the possible effects of a number of working conditions on the afterglow characteristics of luminous fibers. The fibers in our studies did not show any significant change in their afterglow brightness and duration after storage for 12 months under conditions of constant temperature and humidity, after 5 hours of light exposure, or soaking in water for 4 hours. The insignificant decay appears to follow the same mechanism. Thermal perturbation seemed to cause some changes to the initial brightness and decay time with the best performance being observed at about 80°C. Moreover, contact with acid or base for 5 minutes only resulted in slight reduction of the afterglow brightness. Our studies thus indicate a high degree of stability of the afterglow performance of the luminous fibers used.

Studies of the water adsorption on Lampung’s natural zeolite of Indonesia for cooling application

Part of minerals that originally formed from volcanic rock and ash layers reacting further with alkaline groundwater is called natural zeolite, where its sources are not always available in all countries. Indonesia is located in the ring of fire which have a huge sources of zeolite, one of the area is Lampung, South Sumatra. Natural zeolite has been considered as one of potential heat adsorbent medium which can contribute to the energy consumption and reduce air pollution in the using of cooling application. The characteristic of this Lampung natural zeolite such as adsorption kinetics, adsorption water uptake, and adsorption capacity were test with ASAP 2020 system. Sorption kinetics by this experiment of zeolite samples were carried out in a constant temperature and humidity chamber. The chamber can supply constant air condition with deviations of ±0.5 °C for temperature and ±3% for relative humidity. The data based on rate of adsorption and the defined working condition was set as 20°C and 70% RH. Pore volume is a significant parameter for determining the limitation of water uptake, which can describe the saturated condition of zeolite. Sorption isotherm models used to describe sorption phenomena are commonly deduced from the Polanyi potential theory were investigated. The water adsorption quantity increased with the increase of relative pressure. To sum up, this pure zeolite has a less heat and mass transfer performance so its need to be activated before using in cooling application to get their great potential and by being coated in a desiccant heat exchanger systems.

Heating and dehydration of grain and cereals at a combined energy supply

The paper dwells on the development of experimental dependencies of heating and dehydration of grain and cereals when varying the irradiance, ambient temperature in the heat treatment zone and the initial moisture content of product, and the development of the mathematical models for heating and dehydration of some grains and cereals. The grain was heated on the laboratory equipment with quartz halogen linear infrared emitters. The irradiance on the working surface in the treatment zone was determined by calculation using a specially developed program. The ambient temperature was determined by a thermocouple thermometer placed in a ceramic tube. The grain temperature was estimated as average by weight by a thermocouple thermometer after its transfer into a thermally insulated container. The following dependencies have been obtained: 1 - Temperature dependence of the heating time for different heating modes and initial moisture content. 2 - Dependence of moisture content on the heating time under different conditions and initial moisture content. 3 - Dependence of moisture content on a temperature under different conditions and constant initial humidity. The models of the heat-moisture exchange and dehydration processes have been created, and the model parameters K0 and KT of the temperature dependence of some grains have been identified, as well as their dependence on moisture content and treatment modes has been evaluated. It has been established that this model describes adequately the process of dehydration to an extent limited by the upper temperature value of grain not much more than 100 ºÐ¡. Within not limited to the upper temperature value of grain not much more than 100 ºÐ¡. From the presented graphs and earlier obtained results for barley and millet, it can be assumed that the model describes adequately experimental data on the small-sized (3 - 5 mm) objects.

Experimental verification of shrinkage due to drying in concrete under varying humidity conditions in accordance with the Eurocode2 standard

The concrete shrinkage depends on many factors. There are the concrete mixture, dimensions of the element and environment conditions, mainly humidity. All these factors can be imposed under laboratory conditions and controlled. In field conditions, however, a constant humidity is not possible to keep. The paper presents the impact of relative humidity changes on the values of shrinkage strains. The experimental results obtained on the specimens (with size 150x150x600 mm) were compared with the values calculated in accordance with the Eurocode 2 standard. The specimens were made with basalt aggregate without admixtures or additives. Two kinds of cement were used in preparing the specimens: Portland and blast-furnace slag cement. All specimens were treated in water for 10 days in the first days after demoulding and then subjected to testing. During the 56 days the temperature was 22 ± 2°C, while the humidity decreased proportionally from 91% to 47%. Strains were measured and the specimens were weighed to determine the mass loss. The experimental results were compared to the computational results. It should be concluded that they were not coherent in the case of ambient humidity exceeding 80% although it was accordance with the Eurocode 2 standard.

Extending dew-point temperature scale up to +50 °C

Extension of dew-point temperature scale has been performed using a two-temperature (2-T), constant pressure humidity generator that is developed for the first time by the National Institute of Standard (NIS) in order to extend the calibration capabilities to the high dew-point temperature range at NIS. It relies on the saturation of a stream of gas flowing over a water surface maintained at constant, well-known, temperature. In this paper, primary realization of dew-point temperature scale in a dew-point temperature range up to +50 °C was performed to extend calibration capabilities and to improve the uncertainties of the dew-point temperature scale realization. Several experiments were carried out in order to characterize the generator. Characterization comprises studies of the saturator efficiency, temperature stability and a comparison with a calibrated chilled-mirror hygrometer. The results of the efficiency tests showed good performance of the generator. For uncertainty of measurements, a thorough analysis was also described representing estimations of contributions for all the sources that possibly affect measurements.

Study Regarding the Professional Sports Practice Possibilities of the Slanic Moldova Area, in Bacau County

This study highlights both the financial aspects necessary to support sports, and the biochemical aspects related to exercising in a controlled environment, under conditions of constant temperature and humidity, and saline air. The paper also proposes the construction of a sports training base in a part of the Târgu Ocna Salt Mine, which could have beneficial effects regarding both sports results and the revitalization of tourism in that area. The study has emphasized also the fact that there is an insufficient promotion of the so-called "sports tourism", which leads to an insufficient occupation of the accommodation spaces of the resort. There is a need for a database that would be made available to the sports clubs, for them to be able make the best choice to conduct their centralized training.