Effect Of Different Relative Humidities Research Articles

Research on the influence of relative humidity on the purification efficiency of sponge activated carbon system purification system

An indoor air purification system coupled with adsorption and heat storage was designed based on a prefabricated building, which has the advantages of high purification efficiency, does not take up indoor space and does not require additional power consumption. It has been shown that the relative humidity has a significant impact on the purification effect of particulate matter. Using sponge activated carbon as adsorption material, the effect of different relative humidity on the purification efficiency of PM2.5 and PM10 was experimentally studied, and the purification effect of the purification system on PM2.5 and PM10 under various relative humidity conditions was analyzed. The results show that in the relative humidity interval of 20%-70%, with the increase of relative humidity, the sponge activated carbon purification system shows an increasing trend in the purification efficiency of PM2.5, and the effect on the purification efficiency of PM10 is not obvious.

Miyeokgui (Undaria pinnatifida Sporophyll) Characteristic under Different Relative Humidity: Microbial Safety, Antioxidant Activity, Ascorbic Acid, Fucoxanthin, α-/β-/γ-Tocopherol Contents.

This study aimed to investigate the effects of different relative humidities (%) on the microbial safety, antioxidant activity, ascorbic acid, fucoxanthin, and tocopherol contents of Undaria pinnatifida sporophyll powder (UPSP) stored for 4 weeks. The caking phenomenon did not occur in the 11-53% relative humidity conditions, but it did in the 69%, 81%, and 93% relative humidity conditions with caking index values of 88.30%, 99.75%, and 99.98%, respectively. The aerobic bacterial contents increased drastically in samples stored at 69-93% relative humidity. Ascorbic acid was unstable at high relative humidity, but fucoxanthin and tocopherol were more unstable at low relative humidity. Therefore, it was most stable at intermediate relative humidity. The 69% relative humidity sample had higher DPPH (12.57 g BHAE/kg), ABTS (4.87 g AAE/kg), and FRAP (4.60 g Fe (II)/kg) than the other samples. This study could be helpful for the storage and transport of UPSP under optimum relative humidity conditions, which can significantly prevent quality losses.

Evaluating the Stability of a Novel Nutraceutical Formulation Combining Probiotic Limosilactobacillus fermentum 296, Quercetin, and Resveratrol Under Different Storage Conditions.

This study evaluated the stability of a novel nutraceutical formulation composed of the probiotic Limosilactobacillus fermentum 296, quercetin (QUE), and resveratrol (RES) (LFQR) under different storage conditions. The effects of different relative humidities (RH; 11, 22, and 33%) and storage temperatures (refrigeration temperature -4°C and room temperature -25°C) on the stability of LFQR were evaluated through the determination of thermal stability, viable cell counts, bacterial physiological status, antioxidant capacity, and contents of QUE and RES during long-term storage. RH did not affect endothermic reactions and mass reduction in LFQR. After a 15-day-humidification period, L. fermentum 296 had higher viable cell counts in LFQR under refrigeration temperature storage when compared to room temperature storage regardless of the RH. The physiological status of L. fermentum 296 in LFQR was overall similar during 90days of storage (11% RH) under refrigeration and room temperature. L. fermentum 296 had the highest viable cell counts (> 6 log CFU/g) in LFQR up to day 90 of refrigeration storage (11% RH). LFQR kept high contents of QUE and RES and maintained antioxidant capacity during 90days of storage under refrigeration and room temperature. The results showed that the higher stability and functionality of LFQR during long-term storage should be guaranteed under 11% RH and refrigeration temperature.

Effect of relative humidity, storage days, and packaging on pecan kernel texture: Analyses and modeling.

The studies expounding on the effects of storage conditions on texture changes are limited. The researchers have been proposing methods to measure pecan texture instrumentally. But current protocols and/or attributes fail to address huge variability during experimentation. Additionally, there are no predictive models to estimate changes in pecan texture during storage. This study addresses all the above concerns and investigates the effects of different relative humidity (RH, 30-90%) and packaging material (Polyethylene-Nylon [PEN], polypropylene [PP], low density polyethylene [LDPE], and metallic laminates [ML]) on pecan texture, introducing a rift ratio (F/H or fracturability to hardness ratio) to address variability in the data and predictive model to estimate changes in the textural attribute of pecans during storage. The textural analysis was conducted on pecan cores and intact pecans to measure the area under curve, fracturability, hardness, cohesiveness, chewiness, springiness, and rift ratio. It was observed that values for the rift ratio obtained using the intact pecan method had high R2 (0.72) as compared to the rest of the textural attributes. A three-parameter logistic model was employed to predict pecan texture during storage. The pecans stored at 75, 80, and 90% reached the rift ratio (F/H) of 0.5 at approx. 115, 3, and 0.15 days (~ 4hr), respectively. Similarly, pecans stored in LDPE, PP, and PEN packs at 80% reached rift ratio (F/H) of 0.5 at approx. 26, 57, and 78 days, respectively. The presence of any kind of package delayed fracturability loss by at least eight folds at 80% RH. The pecans stored in ML did not experience a significant change in textural attributes.

Hot-air impingement roast drying of beef jerky: Effect of relative humidity on quality attributes

To mitigate encrustation of beef jerky and improve quality during hot-air impingement roast drying (HIRD) process, the effect of different relative humidity (RH) conditions (NO (about 2.3%), 10%, 15%, 20%) at a constant roast drying temperature of 120 °C on “encrustation” thickness, cooking yield, microstructure, tenderness, color, myoglobin, lipid oxidation, flavor and sensory quality of beef jerky were explored. Results indicate that improving RH decreased the “encrustation” thickness of beef jerky significantly (p < 0.05) as the moisture distributed more evenly shown by magnetic resonance imaging analysis. Microstructure observation showed that the number of gaps between muscle bundles decreased and muscle bundles become plumper at both cores and edges of beef jerky with an increase of RH. Meanwhile, humidification could improve the color quality of beef jerky, decline the content of malondialdehyde (MDA) as well as enhance the flavor of beef jerky. The findings in this work indicate that humidification enhances the quality of beef jerky by alleviating surface encrustation, improving color, reducing lipid oxidation, and enhancing roast drying flavor during HIRD processing.

Effect of relative humidity on the enhancement of the triboelectrification efficiency utilizing water bridges between triboelectric materials

The emerging triboelectric nanogenerator (TENG) technology has reignited research interests in the well-known triboelectrification. Understanding triboelectrification in different humidity conditions has become essential because the relative humidity is a key factor that influences triboelectricity and the output of TENGs. This study uses a capsule TENG as the experimental platform to investigate the effect of different relative humidity (RH) conditions on the triboelectrification of material pairs commonly used in TENGs. Different from the traditional cognition that the number of triboelectric charges decreases with increasing relative humidity, we find that the commonly used triboelectric material pair has its own unique, optimal, relative humidity. The electric output increases with increasing RH and then decreases as the RH reaches and passes an optimal value. The working mechanism related to the formation of water bridges that leading to the enhanced triboelectrification is discussed. Moreover, we find that the exact optimal RH are existed for commonly used triboelectric material pairs. A data table showing the optimal RH for those commonly used material pairs is provided. We find that most of the optimal RH values are concentrated in a small RH range (28–35%), even though a few material pairs have larger optimal RH values (53%). This study presents new insight into the effect of relative humidity on the performance of TENGs and provides a relatively complete set of data on the optimal RH for commonly used material pairs, which may become a critical reference for those designing working conditions for TENGs.

Effect of humidified intake air on a turbo-charged DICI engine: Performance and emission analysis

Diesel engines have been using extensively in the automotive industry, power generation systems and marine applications. However, diesel engines release massive nitrogen oxides and soot emissions. Several countries or associations have framed very stringent emission regulations for protecting the environment. In this investigation, the effects of different relative humidity (RH) levels; 40, 50, 60, 70 and 80% (approximately) of intake air on the performance and emission parameters of four-stroke single cylinder turbocharged diesel engine have been analyzed. Load (brake power) ranging from 0.5 to 3 kW are varied. Firstly, the experiments are conducted on a conventional diesel engine (CDE); i.e., naturally aspirated condition, assembled turbocharger with CDE and continued with different RH levels. Further, engine performance analysis such as BSFC and BTE are evaluated, and emissions such as CO, HC, NOx and Soot opacity are measured and compared to CDE. The experimental results revealed that BTE, CO and HC emissions are significantly increased while BSFC, NOx, and Soot emissions are decreased as RH levels increase with particular loads as against CDE. For the maximum operated load at 80% RH level, the maximum reductions in BSFC, NOx and Soot emission are achieved as 4.9%, 30.6% and 58.4% respectively, whereas BTE is enhanced by 4.7%. CO and HC emissions are decreased upto the operated load and increased with an increase in the RH level. The maximum reduction in BSFC and increment in HC and CO emissions are achieved at low load compared to peak load operation with an increase in the RH level.

Oil yield, physicochemical characteristics, oxidative stability and microbial safety of perilla seeds stored at different relative humidity

This work investigated the effect of different relative humidity (RH) on the oil yields, physicochemical characteristics, oxidative stability, and microbial safety of perilla seed (PS) stored for 12 weeks. The PSs stored at 11 % RH gave the highest oil yield (34.24 g/100 g PSs), about 7.5-times higher compared with the yield from PSs stored at 93 % RH. During storage at 69–93 % RHs, the lightness (L*) decreased and the redness (a*) and yellowness (b*) increased, indicated a dark-brownish color. The PSs stored at 33–43 % RHs had higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (85.74 %) and iodine value (190 g/100 g sample) and lower acid value (1.40 mg KOH/g sample) and peroxide value (4.35 meq/kg sample) as compared with other PSs samples. During storage, the aerobic bacterial contents (3.08 log10 cfu/g) in PSs were plateaued at 11–69 % RHs, and significantly increased at 81–93 % RHs. Yeasts and molds were found only for those of the PSs stored at 69–93 % RHs. At higher RH (81–93 %), the microbial contents were uncountable due to too much growth after two weeks. This study could be useful for an appropriate storage condition to maintain quality in terms of oxidative stability and retarding microbial growth of PS.

Effects of Different Relative Humidities on Flax Fibers prior to Manufacturing Their Composites Based on the Shear Response

The moisture absorption behavior of flax fiber-reinforced epoxy composites is deliberated to be a serious issue. This property restricts their usage as outdoor engineering structures. Therefore, this study provides an investigation of moisture in flax fibers on the performance of the flax/epoxy composite materials based on their shear responses. The ±45° aligned flax fibers exposed to different relative humidities (RH) and the vacuum infusion process was used to manufacture the composite specimens. The optimum shear strength (40.25 ± 0.75 MPa) was found for the composites manufactured with 35% RH-conditioned flax fibers, but the shear modulus was reduced consistently with increasing RH values. Although shear strength was increased because of fiber swelling with increased moisture absorption rate until 35% RH environments with good microstructures, nonetheless, strength and modulus both started to decrease after this range. A very poor microstructure has been affirmed by the SEM images of the composite samples conditioned at 90% RH environments.

MATHEMATICAL MODELLING AND IMMEDIATE AND LATENT QUALITY OF NATURAL IMMATURE COFFEE UNDER DIFFERENT DRYING CONDITIONS

ABSTRACT This work aimed to study the immediate and latent effects of different relative humidities on the quality of dried coffee fruits, describe the drying kinetics of natural immature coffee (Coffea arabica L.), and evaluate the mathematical model that best fits the experimental drying data. The drying was carried out in a fixed layer dryer coupled to a composite air conditioning system in which the drying air was controlled with an air flow of 20 m3.min1.m−2, at a temperature of 40 °C, and at relative humidities of 10%, 17.5% and 32.5%. Manually harvested coffee fruits were used and dried to a mean water content of 0.120 dry basis (d.b). After drying, the kinetic curve and the physical and physiological properties were determined. The coffee was stored in permeable packs for 6 months. The electrical conductivity, potassium leaching, and colour analysis were performed every 2 months. For the modelling adjustment, the models were tested, and the Midilli model had the best fit with the drying kinetics of the immature coffee. No immediate damage was observed in the physical and physiological quality of the coffees, and latent damage was perceived after 120 days of storage for the natural immature coffees.

Growth and CO2 exchange in young Phalaenopsis orchids grown under different levels of humidity during the vegetative period

Phalaenopsis plants are distributed throughout tropical regions with high humidity, which is generally necessary for their cultivation. This study was conducted to determine the effects of different relative humidity (RH) conditions on the growth and photosynthetic characteristics of young Phalaenopsis plants. Three-month-old clones of Phalaenopsis ‘Blanc Rouge’ and Doritaenopsis ‘Mantefon’ plants were grown under 30 ± 10, 50 ± 10, 70 ± 10, or 90 ± 10% RH conditions. The RH treatments were maintained for approximately 6 months in environment-controlled growth chambers. The temperature and photoperiod were maintained at 28 °C and 12/12 h, respectively. At the start of the RH treatments, the mean leaf span was 14.2 and 16.7 cm in ‘Blanc Rouge’ and ‘Mantefon’ plants, respectively. In both cultivars, plants grown under 70% RH showed the longest leaf span, which was 25.3 and 20.6 cm in ‘Blanc Rouge’ and ‘Mantefon’, respectively. High-humidity conditions (i.e. 70 and 90% RH) generally promoted the length of leaf span, but the growth rate of leaf span was slightly lower at 90% RH than at 70% RH. CO2 exchange, stomatal conductance, and transpiration rate of the uppermost mature leaf were observed in ‘Blanc Rouge’ plants grown at 30, 50, and 70% RH. The highest rate of CO2 uptake was observed in the plants grown at 70% RH, followed by 50 and 30% RH. The stomatal conductance increased and transpiration decreased with increasing RH. The maximum quantum yield of photosystem II (Fv/Fm) of plants grown under 70 and 90% RH slightly decreased after 9 weeks of treatments, but there were no differences among the treatment groups at the conclusion of the study. These results indicated that high RH (e.g. 70%) slightly increases CO2 uptake and leaf span of young Phalaenopsis plants.

Effect of Relative Humidity on Physiology and Antioxidant Metabolism of Grafted Watermelon Seedlings

This study investigated the effect of different relative humidity (RH) regimes on graft healing of grafted seedlings of watermelon (Citrullus vulgaris Schrad.). Two watermelon cultivars (‘Speed’ and ‘Sambok Honey’) were grafted onto the ‘RS-Dongjanggun’ bottle gourd rootstock (Lagenaria siceraria Stanld.) and the grafted seedlings were maintained under one of three relative humidity regimes, 95-96% [1.1-0.8 (day) or 0.8-0.6 (night) g·m-3 vapor pressure deficit (VPD)], 97-98% [ 0.7-0.4 (day) or 0.5-0.3 (night) g·m-3 (VPD)], or 99-100% [0.3-0.0 (day) or 0.2-0.0 (night) g·m-3 (VPD)] according to the Mollier diagram based on the air temperature of 25°C day/18°C night with 16 h photoperiod per day. Among the RH treatments, 97-98% significantly increased plant height and fresh weight of the rootstock and scion of the ‘Speed’ and it also enhanced the graft union connection of both cultivars after two days of grafting. However, plant height and thickness of the scion of ‘Sambok Honey’ was increased by the 99-100% RH treatment. Furthermore, both cultivars grown in the 95-96 and 97-98% RH treatments consisted of lower levels of endogenous H2O2 and less activities of antioxidant enzymes which illustrated the occurrence of less oxidative stress. Hence, the results of this study identified the optimal RH level for the graft healing of watermelon seedlings.

Effects of Different Relative Humidities on the Corrosion of the Epoxy-Coated Galvanized Steel in the Presence of Sulfur Dioxide

Effects of Different Relative Humidities on the Corrosion of the Epoxy-Coated Galvanized Steel in the Presence of Sulfur Dioxide

The Effects of Different Relative Humidity with Low Temperature on Skin Physiology

People always experience different humidity and temperature in very short span of time. Therefore, people can adapt themselves to the changes of environment by their physiological changes. Many studies had showed that relative humidity (RH) affects thermal regulatory process. However, there is no related research showing the effects of different humidity with low temperature on skin physiology. The purpose of this study was to evaluate the effects of different RH with low temperature on skin physiology. Twenty subjects were selected for this study. All subjects stayed a chamber in 60% RH ands 24°C for 30minutes, and then moved to a chamber of 60% RH and 10°C on the first day. The second day, the combination of the chamber changed to 90% RH and 10°C. Skin temperature and skin water content were tested very minutes from the beginning to the 20th minute. The conclusions indicated that lower RH would induce lower skin temperature. Gender was not a factor to influence the skin temperature on different RH. Skin water content may not easily changed in a short span of time.

A new approach to evaluate the effect of moisture on heat transfer of thermal protective clothing under flashover

It’s urgent to investigate moisture effect on thermal protection of thermal protective clothing in simulated fire scene as accurately as possible. The current bench top tests can’t evaluate thermal protective performance (TPP) of fabrics under microclimate with high temperature and relative humidity (RH). In this paper, to well investigate effect of different RH under microclimate on thermal protective performance of flame-retardant fabrics exposed to flashover, a new modified TPP testing apparatus was developed. It consisted of a typical TPP tester and RH adjustable microclimate chamber. Three kinds of air gaps under fabrics were also employed to simulate different spaces between skin and clothing. The results showed that the temperature increment under microclimate of 35 % RH was highest, and that of 95 % RH was lowest. There was significant temperature difference found among above three adjusted environment. Time required of temperature rise to 12 oC highly prolonged as RH became higher. It could be deduced that the effect of RH on heat transfer became significant as air gap increasing; if the air gap width still increased, the moisture effect diminished. The newly developed testing apparatus could be well used to evaluate the moisture effect on thermal protective performance of flame-resistant fabrics.

Effect of relative humidity on population growth of Apolygus lucorum (Heteroptera: Miridae)

Apolygus lucorum (Meyer-Dur) (Heteroptera: Miridae) is a significant insect pest of cotton, Chinese dates, grapes and many other crops in China, and its populations typically increase after heavy rains. However, the intrinsic mechanism of the rainfall-dependent outbreak is not yet fully understood. In our study, the effect of different relative humidity (RH), 40, 50, 60, 70, and 80% RH, on population growth of A. lucorum was evaluated in the laboratory. High humidity (e.g. 70 and 80% RH) was observed to significantly increase egg and nymph survival, prolong adult life longevity, and improve female fecundity. However, low humidity (e.g. 40 and 50% RH) led to unfavorable effects on survival and fecundity. As a result, the intrinsic capacity for increase (rm), net production (Ro), and the finite rate of increase (λ) of A. lucorum population greatly increased with increasing relative humidity. Additionally, the relationships between rm and Ro and relative humidity were good fits to the logistic models y = 36.82/(1 + Exp(10.76 − 0.19x)) (p < 0.001) and y = 0.10/(1 + Exp(9.26 − 0.19x)) (p = 0.003), respectively. This study provides insight into the phenology of A. lucorum, and may contribute to modeling of its population dynamics.

The Influence of Relative Humidity on Nanoparticle Concentration and Particle Mass Distribution Measurements by the MOUDI

A humidity control system was operated upstream of two collocated MOUDIs (micro-orifice uniform deposit impactors) for sampling ambient aerosol particles. One MOUDI used silicone-grease-coated aluminum foils (ALs) as the impaction substrates and was considered as the reference impactor, while the other used uncoated ALs or uncoated Teflon filters (TFs) as the impaction substrates for quantifying the effect of different relative humidities (RHs) and impaction substrates on the PM0.1 concentrations and mass distributions of ambient PMs. Test results showed that decreasing RH in general increased particle bounce from uncoated substrates with the bounce from uncoated ALs being more severe than that from uncoated TFs. Particle bounce did not influence the overall mass distribution of ambient fine particles when RH ranged between 40% and 80%, whereas it led to undersampling of particles greater than 2.5 μm in aerodynamic diameter severely. Oversampling of PM0.1 occurred by as much as 95%–180% or 25%–55% when th...

English

The purpose of this investigation was to compare the effects of different relative humidity (RH) on the microcosmic conformation of the recombinant AAV-2 virion at 22°C. rAAV-2 virions prepared on copper grid were placed in a high, middle or low RH cabinet and incubated for 72, 48 and 24 h, respectively. The rAAV-2 virions were observed by transmission electron microscope and the values of major axis length, minor axis length and ellipticity of the rAAV-2 virions were obtained using the IMS cell image analysis system. After incubation for 48 and 72 h, the major axis length and minor axis length of the rAAV-2 virion started to rapidly decrease in high RH. Conversely, the axis lengths rapidly increased in low RH. Then, the ellipticity of the rAAV-2 virion would almost tend to approach the identical value of 0.9 for 48 and 72 h incubations in high RH. The results suggest that the rAAV-2 virion tended to favor a smaller, round, more stable conformation in high RH compared to low RH which implied that the rAAV-2 virion was probably prone to living in high relative humidity conditions.

Anther opening, pollen biology and stigma receptivity in the long blooming species, Parietaria judaica L. (Urticaceae)

Background and aims This paper is about pollen ecophysiology, anther opening, pollen dispersal and the timing of the male and female phases in Parietaria judaica (Urticaceae). Methods Ecophysiological (effects of different relative humidities (RHs) and osmotic relationships) and cytological methods (stigmatic receptivity, pollen viability, histology and histochemistry) were used to determine pollen and pollination features during the long blooming period of this species. Key results Pollen is dispersed by rapid uncurling of the filament and anther opening. The filament and anther lack cells with lignified wall thickenings, which are usually responsible for anther opening and ballistic pollen dispersal. Instead, dispersal is the result of the sudden movement of the filament. Pollen is of the partially hydrated type, i.e. with a water content greater than 30% at shedding, and readily loses water, and hence viability, at low RH. Pollen carbohydrate reserves differ with season. Starchless grains germinate quickly and are less subject to water loss. Flowers are protogynous, pollen release occurring only after complete cessation of the female phase within an inflorescence. Conclusion Parietaria has partially hydrated pollen which differs from typical pollen of this type because of its reduced size and the absence of callose. Because of its low water content at the time of shedding it survives better at higher RH. Dispersal and pollination are adapted to pollen features.

Studies on Acrylonitrile-Butadiene (NBR) Latex-Reinforced Jute Nonwoven Fabric Composites: Chemical Resistance, Mechanical Properties, and Water Absorption

Composites were fabricated by impregnating the jute nonwoven fabric in a bath of acrylonitrile-butadiene (NBR) latex. The effects of different pickup ratios (dry-to-dry weight) of jute nonwoven fabric to NBR latex viz., 1:0.5, 1:1, 1:1.5, 1:2, and 1:2.5 on the performance of composites have been studied. The fabricated composites have been evaluated for physico-mechanical properties and chemical resistance. Percent water absorption of composites has been determined both at room temperature and boiling water. Effects of different relative humidity on the equilibrium moisture content of the natural jute nonwoven fabric-NBR composites have been evaluated.