Humidity Regulation Research Articles

Striving for order and compositional homogeneity in bulk mesoporous zirconium titanium mixed metal oxides from triblock copolymers and metal chlorides

Under consideration in this work is the prospect for the preparation of ordered, thermally stable, compositionally homogenous bulk zirconium titanate mesophases using a triblock copolymer template (F-127). As a starting point, well established evaporation-induced self-assembly procedures for the production of thin films have been adapted to the preparation of bulk materials. The composition of the precursor solution was fixed at Zr x Ti 1− x Cl 4:40 EtOH:0.005 F127: h H 2O ( x = 0.28, h = 10) and ambient humidity was varied in a systematic and precise fashion. It has been demonstrated that while it was possible to prepare materials with localized order at humidities exceeding about 20% relative humidity, these materials showed macroscopic phase segregation with very little zirconium entering the mesophase structure instead precipitating as zirconium oxide. This phase segregation resulted in poor thermal stability at 500 °C. In contrast, at humidities below about 20%, more thermally stable worm-like materials with compositional homogeneity on the transmission electron microscope length scale could be prepared. For comparison with bulk materials, thin films were also prepared from the similar precursor solutions. The results of these preparations were unexpectedly very similar to those of the bulk preparations. It has been clearly demonstrated that attempts to incorporate about 30 mol% zirconium resulted in destruction of long range mesoscopic ordering under the conditions used. An additional important result of this study is the observation that the pore size distribution (PSD) was shifted from about 2.5 nm to about 6.5 nm for an increase in relative humidity from 0% to 20% and from 6.5 to about 7.6 nm for relative humidity increase from 20% to 70% for a calcination temperature of 300 °C. At this temperature all materials remained stable although similar overall trends were observed in the pore diameter with humidity when the calcination temperature was increased to 500 °C even though there was evidence of phase segregation and pore collapse at this temperature especially for samples prepared at the higher humidities. The present results suggest therefore that regulation of humidity during evaporation step affords a certain level of control over porosity.

F-63 室内における調湿建材による調理臭の除去効果の検討

F-63 室内における調湿建材による調理臭の除去効果の検討

Factors Limiting Convective Cloud-Top Height at the ARM Nauru Island Climate Research Facility

Abstract Cumulus congestus clouds, with moderate shortwave albedos and cloud-top temperatures near freezing, occur fairly often in the Tropics. These clouds may play an important role in the evolution of the Madden–Julian oscillation and the regulation of relative humidity in the midtroposphere. Despite this importance they are not necessarily simulated very well in global climate models. Surface remote sensing observations and soundings from the Atmospheric Radiation Measurement (ARM) climate research facility at Nauru Island are coupled with a simple parcel model in order to address the following questions about these cloud types: 1) Which environmental factors play a role in determining the depth of tropical convective clouds? 2) What environmental parameters are related to entrainment rate in cumulus congestus clouds? The results presented herein suggest that at Nauru Island a drying of the midtroposphere is more likely to be responsible for limiting congestus cloud-top heights than is a stabilizing of the freezing level. It is also found that low-level CAPE and the RH profile account for the largest portion of the variance in cumulus congestus entrainment rates, consistent with the idea that entrainment rate depends on the buoyant production of turbulent kinetic energy. If the analysis is limited to cases where there is a sounding during the hour preceding the cumulus congestus observations, it is found that the low-level CAPE accounts for 85% of the total variance in entrainment rate.

Air temperature regime in a forced ventilated greenhouse with rose crop

The use of forced ventilation for greenhouse cooling and air humidity regulation purposes has been expanded around Mediterranean area. The aim of the present study was the experimental investigation of the variables, as well as their interaction, affecting the air temperature in a fan-ventilated greenhouse. On this purpose, measurements concerning both the greenhouse ventilation rate and climate variables inside and outside the greenhouse (air temperature and solar radiation inside and outside the greenhouse and outside wind speed and direction), were carried out in a multi-span fan-ventilated greenhouse. The greenhouse was cultivated with a rose crop and located near Karditsa, central Greece. The results showed that the difference between inside and outside air temperature was strongly related to the ventilation rate as well as to the incoming solar radiation. This finding allowed suggesting a simplified model of the greenhouse energy balance and finally an equation relating the greenhouse air temperature to the outside climate variables (air temperature, solar radiation and wind speed) and the greenhouse characteristics (cover transmission and ventilation rate). The calibration of the model gave satisfactory results and showed that it could be incorporated in algorithms used for greenhouse climate control and also that it could be used as a functional tool for more accurate estimations of ventilation needs.

MR imaging of newborns by using an MR-compatible incubator with integrated radiofrequency coils: initial experience.

To meet the needs of term and preterm neonates undergoing magnetic resonance (MR) imaging, an MR-compatible incubator with air, temperature, and humidity regulators and integrated radiofrequency coils was evaluated. Nine brain, two cardiac, and two pelvic examinations were performed by using a 1.5-T clinical MR imaging unit. The axillary temperature of the newborns varied by less than 0.8 degrees C, their vital signs remained stable, and no complications were encountered. The diagnostic quality of images obtained with the MR-compatible incubator was superior to that of images obtained with the standard MR imaging equipment. The use of an MR-compatible incubator for examinations of ill neonates is feasible and safe and yields excellent MR images.

Relative humidity is a key factor in the acclimation of the stomatal response to CO(2).

Previous work has shown that stomata of growth chamber-grown Vicia faba leaves have an enhanced CO2 response when compared with stomata of greenhouse-grown plants. This guard cell response to CO2 acclimatizes to the environmental conditions on the transfer of plants between the two environments. In the present study, air relative humidity is identified as a key environmental factor mediating the changes in stomatal sensitivity to CO2. In the greenhouse environment, elevation of relative humidity to growth chamber levels resulted in an enhanced CO2 response, whereas a reduction in the light level to that comparable to growth chamber conditions had no effect on stomatal CO2 sensitivity. The transfer of plants between humidified and normal greenhouse conditions resulted in an acclimation response with a time-course matching that previously obtained in transfers of plants between greenhouse and growth chamber environments. The high stomatal sensitivity to CO2 of growth chamber-grown plants could be reduced by lowering growth chamber relative humidity and then restored with its characteristic acclimation time-course by an elevation of relative humidity. Leaf temperature was unchanged during this restoration, eliminating it as a primary factor in the acclimation response. Humidity regulation of stomatal CO2 sensitivity could function as a signal for leaves inside dense foliage canopies, promoting stomatal opening under low light, low CO2 conditions.

Relationship Between Broiler Breeder's Age and Egg Weight Loss and Embryonic Mortality During Incubation in Large-Scale Conditions

The age of broiler breeders is an important parameter to be taken into account by the hatchery manager. Eggs produced by young or old breeders do not hatch as well as the eggs from the breeders of 40 to 42 wks of age. Field reports indicate that there are quadratic relationships between age of breeders and absolute egg weight loss during incubation, age of breeders and hatchability, and age of breeders and embryonic mortality. There is a trend of optimum relative egg weight loss on Day 18 of incubation for the highest hatchability. These results indicate that the eggs that incubate best are produced by the hens of 40 to 42 wk of age. It is suggested that the egg characteristics and the age of breeders have to be taken into account during incubation in order to design optimal incubation conditions and to improve hatchability. However, because the relative egg weight loss is not linked to the age of breeders, regulation of relative humidity during incubation to achieve optimum weight loss may take into account only the eggs characteristics.

Influence Of Different Surface Systems AndHumidity-controlled Ventilation Systems WithHeat Recovery On The Indoor Climate In Flats

In Austria a lot of buildings suffer from rising damp and weathering, so that a high moisture content exists in the construction. Frequently problems start after the reconstruction, because new airtight windows are built-in and the high moisture content in the walls induces mould growth and other unhealthy and uncomfortable states. Investigations are done to simulate the behaviour of rooms in buildings with moisture problems to calculate the indoor climate. By the usage of prediction tools for construction behaviour and indoor climate it is possible to evaluate methods like mechanical air change with and without heat recovery, additional heating or different surface finishes. A ventilation device with humidity regulation and heat recovery can be used successfully to guarantee a comfortable and healthy indoor climate. In the paper the interaction and influences of moisture controlled ventilation with or without heat recovery on the moisture states of the indoor air are presented. In the recent past render systems, which have a low capillary moisture transport capability, have been developed for the renovation of such buildings. Investigations about the success of those measures showed different results. A sufficient exact prediction is available using a new developed program, which is able to predict the indoor climate under a given usage and the coupled heat and moisture transfer (vapour + liquid) in constructions. The simulation gives

Involvement of nitric oxide (NO) in signal transduction of stomatal opening

The stomatal aperture responses to a range of stimuli including light, humidity, CO2 level, air pollutants and growth regulators (eg. abscisic acid and auxin). Blue light is known to induce stomatal opening through the activation of H+-ATPase. Recent papers have suggested that hydrogen peroxide (H2O2) is involved in abscisic acid-induced stomatal closing. Complex pathways of signal transduction have been considered to regulate these stomatal movements. However, a full picture of the pathways has not been drawn yet. We have recently reported that nitrate reductase produces nitric oxide (NO) by the reduction of nitrite, implicating the enzyme as an NO signal emitter. Here we demonstrate that NO is involved in the mechanism for stomatal opening. We measured stomatal apertures of abaxial epidermis peels of Vicia faba leaves. After the treatment of peels with a NO donor S-nitroso-N-acethylpenisilamine (SNAP), stomatal apertures increased to 1.3-fold of those without SNAP in 15 min. Stomatal aperture was also increased by the presence of supplemental nitrite that can be converted to NO via the reaction of endogenous nitrate reductase. Viagra ©, which inhibits cGMP degradation in the NO signaling pathway of humans, suppressed the H2O2-induced stomatal closing movement. These results suggest that the signal transduction system of guard cells includes an NO-dependent signaling pathway

Design, technical specification, and operation of growth chambers with a computer-controlled system for regulating relative humidity suitable for ecophysiological experiments with bryophytes

The control and precise definition of the humidity conditions in experiments on bryophyte performance under controlled conditions is important. However, this aspect is often neglected in ecophysiological and ecological research. The construction, operation and application of growth chambers with a computer-controlled regulation of ambient relative humidity (RH) is described and the chamber performance is characterized. The chambers have moist rockwool at the bottom and are fitted with Plexiglas plates, one fan and one RH sensor each. Evaporation from the plant material and the moist substrate give an increased relative humidity within the chamber and a stable RH is obtained by removing excess humidity. The RH is monitored and controlled by a fan which starts and draws humid air out of the chamber at user-selected RH levels. Horizontal light gradients were found to be small when neutral filters were used on the lids. Chamber temperature followed the temperature of the surroundings, with a lag in temperature drop during night. The stability of the RH levels is dependent on the difference in humidity between chamber and external environment and this gave diurnal humidity fluctuations in chambers regulated at levels near the extremes of a wide humidity gradient. More constant RH levels were obtained with a shorter RH range and optimum performance of the regulation system was obtained when the difference in RH between chamber and the surroundings was moderate. Thus, optimal performance and the widest range of applications can be achieved when humidity and temperature of the external environment can be controlled. Temperature differences among chambers were small and did not affect the humidity gradient. The system permits a convenient and accurate regulation of RH with a short- and long-term stability and reliability.

家屋模型を用いたゼオライトパネルの吸放湿性能に関する屋外実験

A zeolite is mineral resource that has good adsorption and desorption performance for humidity regulation. In this study, in order to verify the effect of zeolite panels utilized for the residential space, field measurement using three 1/3 scale models was conducted. Each of these models has different area of the zeolite panels on the inner wall. The performance of the zeolite panels was clarified by comparing the indoor temperature and humidity between each of models. This paper describes the results of both short term measurement in summer/winter and one-year measurement.

The biology, ecology, and management of the cat flea.

The cat flea, Ctenocephalides felis felis, is the most important ectoparasite of domestic cats and dogs worldwide. In addition to its annoyance to pets and humans, C. felis felis is responsible for flea bite allergy dermatitis and the transmission of dog tapeworm. The abiotic and biotic factors that affect the development of immature stages are reviewed with special emphasis given to those aspects directly affecting control. Factors influencing host selection and feeding by adults are summarized. Recent studies concerning mating and oviposition, especially as they impact the likelihood of survival by immatures, are discussed. There has been an increase in the number of reports of insecticide resistance in the past ten years. Greater attention has been placed on disrupting larval development in modern IPM programs. The immature stages of the cat flea are extremely susceptible to environmental factors such as temperature and relative humidity and insect growth regulators (IGRs). In recent years, the control of cat fleas has increasingly relied on the use of IGRs applied to the host or to the indoor environment. Finally, we discuss advances in pesticide chemistry that provide tools for better control of adult fleas on the host.

Humidity regulation in the management of asthma patients sensitized to house dust mites

Substances in the faeces of house dust mites are well-recognized as common allergens in the pathogenesis of asthma. There have been many trials of interventions aimed at reducing mite populations in the home, but most have been uncontrolled, too small, or too short to determine with confidence any beneficial effects. Of those which succeeded, very few used methods which reduced mite populations on a permanent basis. House dust mites are sensitive to humidity. Their geographical distribution is closely correlated to the availability of moisture. Very little work has been done on the effects of reducing humidity in the home environment in the long term, with a view to controlling dust mite populations. Two different methods which might reduce humidities to levels which could successfully reduce dust mite numbers are dehumidifiers, and mechanical ventilation with heat recovery (MVHR). To date there has been no work assessing the effectiveness of dehumidifiers and very little (although promising) work on MVHR. We discuss the potential of humidity control as an adjunct to the clinical treatment of asthma.

NEW APPLICATIONS OF HEAT PUMPS IN DRYING PROCESSES

ABSTRACT Heat pumps in combination with fluidized bed driers have been investigated extensively at The Norwegian Institute of Technology. A laboratory plant was constructed and a series of experiments on different types of temperature sensitive products were executed. By using heat pump, good temperature and humidity regulation is achieved. Drying temperatures can be regulated from −20°C to 50°C. This gives the possibility of freeze-drying at atmospheric pressure, and drying at temperatures above 0°C in the same plant. By using a temperature program, including an initial period of freeze drying, it is possible to regulate the products' physical properties. Examples are: the sinking velocity of fish fry feed, rehydration ability, colour and taste of dried fish, meat and vegetable products. Further, biotechnological products like bacterial cells and biomolecules/enzymes were dried with improved biological activity of the products compared to traditional drying methods like vacuum freeze drying or spray drying.

空気組成制御および培養液添加が可能な強制通気植物培養容器システムの開発

The authors developed an aseptic plant tissue culture vessel system which enabled ventilation, air composition control, and the addition of nutrient solutions (see Fig. 1). One feature of the system is that two kinds of germ filters are attached directly to the culture vessel (see Fig. 1, Fig. 2, and Fig. 3). One filter is for forced ventilation and the other is for the addition of nutrient solutions.The merits of the system we developed are as follows: (1) Number of air changes is maintained at a desired value without sterilization of the ventilated air and without risk of contamination. It is therefor possible to increase the number of air changes much more than in present aseptic culture vessels wherein ventilation is induced by diffusion. (2) Accordingly, air composition control is very easily achieved. For example, air humidity in vessels is easily kept at the desired value by regulating the water temperature in the bottle of humidity regulator, as shown in Fig. 1. Furthermore, CO2 enrichment is easily practicable. (3) The addition of nutrient solutions during cultivation is achieved easily and quickly (about one minute for addition of 5cm3 solution into a vessel) without opening the vessel cap, and no sterilization of the solution is needed. (4) No advance autoclave procedure is needed except for the culture vessel unit (see Fig. 1). No contamination was observed for 10 weeks even if the cultivation was conducted in an un-clean room. (5) When open air (CO2 concentration: ca. 400ppm) was introduced into the developed vessels, the growth of edible lily plantlets was better than those of two controlled plots (Control-P and Control-T plots) (see Table 2). When the CO2 concentration in developed vessels was maintained at 5, 000ppm, the growth of plantlets was about 20 times greater than those of Control-P and Control-T plots (see Table 2).

Optimization of control systems for near-ambient grain drying: Part 2, the optimizing simulations

The method described in Part 1 of this paper was used to find the optimum values of the controlling parameters of a generalized ‘fan-and-heater’ control policy for near-ambient grain drying systems. After a preliminary series of simulations with the near-ambient drying program (STOREDRY) had identified suitable initial estimates and reduced the number of controlling parameters from ten to five, the policy was optimized for a 3 m bed of wheat initially at 20% moisture content and operating over 20 years at Waddington, Lincolnshire from 15 September in each year. Compared with a conventional staged heating policy, not optimized, the optimized policy required 30% less airflow, and 85% less heater power; this gave an overall reduction in cost of 34%. The effects upon the controlling parameters of initial moisture content, grain bed depth and geographical location were also investigated. Simple on-off, and single set-point fan control and heater control policies were also optimized, but neither was as effective as the generalized control policy, because they lacked the flexibility conferred by the continuous adjustment of the control set-point as drying progressed. The manner of this adjustment runs counter to conventional wisdom in that heat (albeit from a smaller heater) is applied more frequently at the start of drying than at its completion when very little regulation of relative humidity is attempted. Further work is in hand to test the improved policy by physical experiments.

室内仕上げ材の調湿効果の定量化と実験に基づく室内熱負荷のシミュレーション

In order to quantify humidity regulation effects of building finishing materials, the calculation procedure based on the inhomogeneous diffusion simultaneous equations of heat and moisture transfer within the hygroscopic region within the materials was proposed. The presented vector-matrix equation was derived from thermal network method. This calculation method allows for the heat and moisture balance in the control volume of a segmented building mass and the boundary conditions such as convective heat transfer, moisture transfer, radiation exchange among inside surfaces, solar radiation and nocturnal radiation. To confirm accuracy of the presented calculation procedure, a series of experiments were performed. A good agreement between measured and calculated values on temperatures and humidities in a small box was observed. Using one-dimensional heat and moisture transfer program, a series of computer simulations on the hour-by-hour basis were performed to identify the effects of interior finishing materials on space heating and cooling loads. The results show large discrepancies in latent heat loads between in the cases of considering and neglecting moisture absorption and desorption.

Development of a solid-substrate fermentor allowing the control of the substrate water activity

An experimental fermentor was designed to allow the regulation of the relative humidity of the circulating air. This air was first saturated with water at a defined dew point temperature. It was then possible to lower the relative humidity by raising the air temperature. The water activity of the solid-substrate was regulated after a waiting time which was determined by the water sorption properties of the substrate used.

A Test for Regulation of Nest Humidity in Two Bird Species

The hypothesis that parent birds regulate nest humidity and consequently egg dehydration by varying ventilation of the nest was tested in the house finch (Carpodacus mexicanus) and the phainopepla (Phainopepla nitens). Injection into the nest cup of dry air or air saturated with water vapor varied nest humidity two- to threefold. This treatment substantially modified egg dehydration, but the frequency at which the adult ventilated the nest was unchanged. These data indicate that these species do not regulate nest humidity.

Effects of ammonium sulfate aerosols on vegetation—I. Chamber design for long duration exposures

A plant growth chamber has been constructed to expose a large number of plants to a uniformly distributed concentration of submicrometer aerosols of known particle size distribution and chemistry for periods up to 3 weeks. The chamber design with features controlled externally provides regulation of wind velocity, temperature, relative humidity, air exchange, lighting, irrigation and aerosol injection. This facility provides adequate plant growth in the presence and absence of submicrometer ammonium sulfate aerosols of known particle size distribution in order to determine deposition rates, mode of entry and effects of submicrometer aerosols on vegetation.