Reduction In Relative Humidity Research Articles

Pore-filled composite membranes for water vapor separation: Bench-scale advancements and semi-empirical modeling

Efficient scale-up processes of gas separation membranes require a thorough assessment of performance across various parameters. Semi-empirical modeling based on theory and empirical data is an attractive approach to predict the required performance. Despite numerous studies on the performance of gas separation membranes depending on internal parameters such as morphology and geometry, relatively few studies on performance dependent on external parameters have been reported. In this study, we propose semi-empirical modeling for the performance of membranes as a function of external parameters using a bench-scale pore-filled composite membranes for water vapor separation. As external parameters, we selected temperature, pressure, relative humidity (RH), and feed flow rate. These parameters influence water vapor permeance, water flux, and RH reduction, which are theoretical indicators of the performance of water vapor separation membranes. A power regression analysis was used to find the power of individual parameters (Y = Coefficient (k) ∙ Xpower), and a multiple linear regression analysis (finite power law model, Y = k ∙ X1α ∙ X2β…) was used to develop a semi-empirical model with the correlations of these parameters. The modeling values closely coincided with measured values, suggesting the effectiveness of the proposed modeling. This method is expected to simplify the prediction of membrane performance, offering valuable insights for potential scale-up processes.

Characterization of temperature and humidity effects on extreme heat stress under global warming and urban growth in the Pearl and Yangtze River Deltas of China

With global warming accelerating, the heavily populated and rapidly urbanized coastal regions of the Pearl River Delta (PRD) and the Yangtze River Delta (YRD) stand as representative areas with mounting concerns about extreme heat stress. This study analyzes differentiated effects of temperature (TAS) and relative humidity (RH) on human heat stress measured by wet-bulb globe temperature (WBGT) in those urban regions based on machine learning and mathematical derivation, while also examining the impacts of global warming and urbanization on prospective heat risks. To generate fine-scale climate projections targeted at the PRD and YRD, two global projections forced by Representative Concentration Pathway (RCP) 8.5 scenario are dynamically downscaled using non-hydrostatic Regional Climate Model version 4.7 (RegCM4), with the urban density and extent updated every year based on Shared Socioeconomic Pathways 5-8.5 (SSP5) scenario, thereby incorporating the transient urban growth into future projections. The bias-corrected downscaled simulations effectively capture the distinct interdependencies between TAS and RH on WBGT across different regions, similar to the observed patterns during the historical period. While the absolute contribution of TAS to WBGT is larger than RH regardless of warming levels and regions, the relative increase in RH becomes more pronounced with warming. Under RCP8.5 scenario, unprecedentedly extreme WBGT is projected to emerge in the far future (2080–2099). In contrast, the effect of urbanization appears to be more dominant in the near future (2030–2049) as urban density under SSP5 scenario is projected to peak around the 2040s and gradually decrease afterwards. The reduction of RH is found in the intensely urbanized areas locally, but it does not significantly lower WBGT because the positive contribution of increased TAS is more dominant. As a result, highly urbanized regions still exhibit higher WBGT compared to other areas. In addition, urban heat island effect is more pronounced for compact areas with high urban density (i.e., PRD) and at night. Despite the smaller temperature increase from urban heat island effect compared to global warming, it can play a critical role in exacerbating heat stress, adding to the already dangerous humid and hot conditions.

Using a pressurized GDE setup to analyze effects of temperature and relative humidity on CO-stripping measurements on a commercial Pt/C ORR catalyst

This study successfully showcases the capabilities of a newly developed pressurized gas diffusion electrode (GDE) setup by conducting cyclic voltammetry and CO stripping measurements at temperatures up to 120 °C, while considering various relative humidity (RH) levels. Our results clearly demonstrate the feasibility of investigating the effects of RH and elevated temperatures above 100 °C using the pressurized GDE setup. In particular, a negative shift in the CO oxidation peak potential upon increasing temperatures is observed, whereas a reduction in RH leads to a positive potential shift of the CO oxidation peak as well as peak broadening. Additionally, our results highlight the heightened sensitivity of the Hupd peak to changes in temperature and RH, resulting in an underestimation of the electrochemically active surface area (ECSA). An essential aspect of this research is the successful replication of trends observed in membrane electrode assembly (MEA) measurements, providing strong validation for the reliability and effectiveness of our pressurized GDE approach as a valuable bridging tool toward MEA testing at elevated temperatures.

Thermal Performance Analysis of a Commercial Space Exposed to Solar Radiations in the Composite Climatic Conditions

People spend majority of their lifetime indoors making comfortable dwellings one of the major requirements otherwise it may primarily impact the occupant’s health and productivity. Indoor temperature and relative humidity (RH) are the two major parameters for determining comfort level, whilst airflow and heat transfer are having an influential role in controlling these parameters. Since solar radiations are the primary source of heat inside a building and ceiling fans play a significant role in improving air circulation. The present study strives to develop a model for evaluating the thermal behavior of commercial space under the influence of solar radiations and ceiling fans. It involves “solar ray tracing” and “3D-Fan zone” models to assess their impact on indoor air quality and thermal comfort. The developed model is validated by comparing the simulated results of air velocity and temperature with experimental data accumulated from space. Further, the validated model is used to evaluate the impact of different levels of solar irradiation between 200 W/m2 and 1000 W/m2 on the indoor environment. Results revealed that an increment of 200 W/m2 irradiations is raising the mean indoor temperature by 0.2 °C, percentage dissatisfaction by 8% while a reduction in RH is reported to be 0.5%.

Heat health during future summers in eastern Asia: The combined roles of circulation, temperature and humidity

AbstractExcessive relative humidity (RH) in combination with high temperature can lead to heat stress, often measured by the Wet Bulb Globe Temperature (WBGT). The Clausius‐Clapeyron (CC) relationship implies that warming reduces RH if no extra moisture is added. Over coastal regions like eastern Asia, however, the predominant summer monsoon favours increased moisture transport from surrounding oceans as a result of enhanced evaporation driven by surface temperature increase. This would lessen the RH reduction by potentially two‐thirds. Based on two ensembles of climate model simulations, this paper examines the competing effects of near‐surface temperature, humidity and circulation patterns in this region and the consequential health risks. Under a high emissions scenario (RCP8.5/SSP5‐8.5), surface temperature could increase by 4 – 7°C with WBGT increases of several degrees by the end of the 21st century. Devastating extreme heat health events could therefore become a frequent occurrence as a result. Overall, our results show how humidity can be just as important as temperature when considering the risks to society of excessive heat.

Review of High Relative Humidity in Catheter Laboratory of a Private Hospital and a Low Energy Consuming Solution

The Relative Humidity in a Catheter Laboratory is desirous to be controlled within a range of 30 to 65% RH. A maximum Relative Humidity (RH) fluctuation of up to 70% is tolerated. A case study is presented whereby a high RH of up to 80% RH has been recorded in the examination room of a Catheter Laboratory (CathLab) in a local Hospital. The conditioned air to the CathLab is supplied through an existing dedicated Chilled Water Air Handling Unit. Two (2) solutions were considered and the technical and commercial comparisons carried out. The first option is an inline dehumidifier system and the second option is to install a portable standalone dehumidifier inside the CathLab examination room. Solutions to address the high Relative Humidity have to be carefully considered as the introduction of in-line dehumidifiers contribute to higher energy consumption. The latter was selected based on commercial reasons. Three (3) weeks of RH monitoring via the building’s Integrated Building Management System (IBMS) was carried out. The readings measured show a drastic reduction in RH to a mean of about 60% RH which meets the end user’s requirement. The cost for the second option was also found to be much lower at about 10% of the first option.

Machine-Learning-Assisted Autonomous Humidity Management System Based on Solar-Regenerated Super Hygroscopic Complex.

High levels of humidity can induce thermal discomfort and consequent health disorders. However, proper utilization of this astounding resource as a freshwater source can aid in alleviating water scarcity. Herein, a low‐energy and highly efficient humidity control system is reported comprising of an in‐house developed desiccant dehumidifier and hygrometer (sensor), with an autonomous operation capability that can realize simultaneous dehumidification and freshwater production. The high efficiency and energy saving mainly come from the deployed super hygroscopic complex (SHC), which exhibits high water uptake (4.64 g g−1) and facile regeneration. Machine‐learning‐assisted in‐house developed low cost and high precision hygrometers enable the autonomous operation of the humidity management system. The dehumidifier can reduce the relative humidity (RH) of a confined room from 75% to 60% in 15 minutes with energy consumption of 0.05 kWh, saving more than 60% of energy compared with the commercial desiccant dehumidifiers, and harvest 10 L of atmospheric water in 24 h. Moreover, the reduction in RH from 80% to 60% at 32 °C results in the reduction of apparent temperature by about 7 °C, thus effectively improving the thermal comfort of the inhabitants.

Indicators for evaluating trends of air humidification in arid regions under circumstance of climate change: Relative humidity (RH) vs. Actual water vapour pressure (ea)

The trend of wetting or drying is an important metric of regional and global climate change. Based on daily meteorological data during 1951–2018 from 10 stations in arid regions of North China, the performances of two indicators, relative humidity (RH) and actual water vapour pressure (ea), in evaluating the trends of air humidification are investigated. Results show that annual RH decreases by 0–0.10% yr−1 during the past decades in almost all (90%) stations, whereas annual ea presents increasing trends in 40% of stations and decreasing trends in the other 60% stations. Therefore, contrasting results are observed in the trends of air humidity reflected RH and ea. Specifically, stations getting significantly drying as indicated by RH, it is tend to getting less drying or even wetting as indicated by ea. These results suggest that it tend to give a misleading conclusion with the trends of RH as indicator in evaluating the trends of regional or global wetting or drying, due to the reduction in RH caused by the accompanying temperature rising under global warming. The other indicator ea is more consistent with the precipitation changes, and suitable for trending analyses of air humidification under such circumstance. Further researches should be done in a larger scale arid region and in different seasons, to investigate the differences in the trends of air humidification indicated by RH and ea, and discuss the response of the changes of wetting or drying to the varied meteorological factors.

Multi-Climate Factors and the Preceding Growth Stage of Vegetation Co-Regulated the Variation of the End of Growing Season in Northeast Inner Mongolia, China

The end of growing season (EOS) is an effective indicator of annual vegetation growth. Previous studies have revealed the dynamics of the EOS with climate change, while the influence of vegetation growth in preceding stage and peak of growing season (POS) on the EOS has not been thoroughly documented. In this study, we used four smoothing methods to obtain EOS dates from the Normalized Difference Vegetation Index (NDVI) in northeast Inner Mongolia (NIM) between 2001–2017, assessed the differences in the spatiotemporal variations of the EOS obtained by the four smoothing methods, and then investigated the impacts of climate factors, summer/ autumn vegetation growth and POS on the EOS. The results showed that the EOS dates obtained with different smoothing methods were broadly consistent in terms of their spatial patterns and temporal trends. In terms of climate factors, the EOS was driven mainly by preseason precipitation for the majority of vegetation types and advanced with increasing precipitation. For the steppe, both minimum temperature (Tmin) and relative humidity (RHU) played the most important roles in regulating the variation of EOS which was delayed with an increase in Tmin and reduction in RHU. Furthermore, our study found an earlier POS and vigorous vegetation growth in summer would jointly advance the steppe EOS, but these relationships were the opposite of each other in meadow and forest regions. Interestingly, the EOS of NIM was more related with vegetation growth in the most recent period before the EOS. This study highlights the importance of ecological processes in the preceding growth stage for understanding the dynamics of EOS.

Characterization of aerosol size distributions and chemical compositions under strong wind and stagnant conditions during haze episodes in Lin’an, China

A long-lasting haze episode which included a strong wind pollution day (SWPD) and stable pollution days (SPD) occurred in Lin’an from January 21 to 26, 2015. On Jan. 21, the Lin’an atmospheric background station experienced a north wind at ground level, which resulted in short-term northern input–based pollution. During January 23 to 26, stable atmospheric conditions led to a local accumulation of pollutants. The average number concentration, surface area concentration, volume concentration, and concentration of PM2.5 were 14,183 ± 7121 cm−3, 576 ± 154 μm2 cm−3, 1009 ± 151 μm3 cm−3, and 145 ± 41 μg/m3 in SWPD; 14,497 ± 7418 cm−3, 1033 ± 241 μm2 cm−3, 1435 ± 540 μm3 cm−3, and 205 ± 44 μg/m3 in SPD. The extinction coefficients calculated in SWPD and SPD were 523.7 ± 281.7 Mm−1 and 918.0 ± 416.9 Mm−1. The number concentration spectra in SWPD were a bimodal distribution, which exhibited peak values at 38 nm and 88 nm (11,422 cm−3 nm−1 and 11,043 cm−3 nm−1). The number concentration spectra in SPD were a unimodal distribution with a peak at 96 nm (15,375 cm−3nm−1). Surface concentration spectra in SWPD and SPD were three-peak distributions with maximum concentration peaks at 230 nm and 575 nm (808 μm2 cm−3 nm−1 and 1087 μm2 cm−3 nm−1), respectively. The volume concentration spectra of SWPD had a four-peak distribution with peaks at 38 nm, 210 nm, 575 nm, and 1.3 μm. Appropriate relative humidity (RH) and particles in the 0.5–1-μm range were the main reasons for lower visibility for SPD. The contributions of ammonium nitrate (NH4NO3), ammonium sulfate ((NH4)2SO4), and organic matter (OM) to the extinction coefficients were 30.3%, 30.1%, and 19.7%, respectively, for SWPD; and 32.1%, 26.3%, and 23.4%, respectively, for SPD. The particles in SWPD came from the long-range transport and conversion of gas to particles, and SO42− and NO3− for SPD were mainly generated by heterogeneous reactions and homogeneous reactions, respectively. It was also determined that the enhancement of atmospheric oxidation resulted in greater secondary organic carbon (SOC) generation, and a reduction in RH led to a decrease in the main water-soluble ions.

Separating Dynamic and Thermodynamic Impacts of Climate Change on Daytime Convective Development over Land

AbstractClimate change affects the dynamics and thermodynamics of moist convection. Changes in the dynamics concern, for instance, an increase of convection strength due to increases of convective available potential energy (CAPE). Thermodynamics involve increases in water vapor that the warmer atmosphere can hold and convection can work with. Small-scale simulations are conducted to separate these two components for daytime development of unorganized convection over land. The simulations apply a novel modeling technique referred to as the piggybacking (or master–slave) approach and consider the global climate model (GCM)-predicted change of atmospheric temperature and moisture profiles in the Amazon region at the end of the century under a business-as-usual scenario. The simulations show that the dynamic impact dominates because changes in cloudiness and rainfall come from cloud dynamics considerations, such as the change in CAPE and convective inhibition (CIN) combined with the impact of environmental relative humidity (RH) on deep convection. The small RH reduction between the current and future climate significantly affects the mean surface rain accumulation as it changes from a small reduction to a small increase when the RH decrease is eliminated. The thermodynamic impact on cloudiness and precipitation is generally small, with the extreme rainfall intensifying much less than expected from an atmospheric moisture increase. These results are discussed in the context of previous studies concerning climate change–induced modifications of moist convection. Future research directions applying the piggybacking method are discussed.

Unravelling effects of relative humidity on lipid barrier formation in human skin equivalents

Relative humidity (RH) levels vary continuously in vivo, although during in vitro generation of three-dimensional human skin equivalents (HSEs) these remain high (90–95%) to prevent evaporation of the cell-culture medium. However, skin functionality is directly influenced by environmental RH. As the barrier formation in HSEs is different, there is a need to better understand the role of cell-culture conditions during the generation of HSEs. In this study, we aim to investigate the effects of RH on epidermal morphogenesis and lipid barrier formation in HSEs. Therefore, two types of HSEs were developed at 90% or at 60% RH. Assessments were performed to determine epidermal morphogenesis by immunohistochemical analyses, ceramide composition by lipidomic analysis, and lipid organization by Fourier transform infrared spectroscopy and small-angle X-ray diffraction. We show that reduction of RH mainly affected the uppermost viable epidermal layers in the HSEs, including an enlargement of the granular cells and induction of epidermal cell activation. Neither the composition nor the organization of the lipids in the intercorneocyte space were substantially altered at reduced RH. In addition, lipid processing from glucosylceramides to ceramides was not affected by reduced RH in HSEs as shown by enzyme expression, enzyme activity, and substrate-to-product ratio. Our results demonstrate that RH directly influences epidermal morphogenesis, albeit the in vitro lipid barrier formation is comparable at 90% and 60% RH.

Plum Rain-Season-Oriented Modelling and Intervention of Indoor Humidity with and without Human Occupancy

The plum rain season, caused by precipitation along a persistent stationary Mei-Yu front in East Asia, creates favorable temperatures and relative humidity (RH) for mold growth indoors. This paper investigates the effects of human occupancy on indoor humidity and investigates the efficient RH reduction methods to prevent mold growth in moist climates. The research is carried out based on a case study which compares a family-occupied home and another unoccupied one during typical plum rain season in Nanjing. Firstly, by analyzing the factors that can influence the indoor air RH, this paper develops a comprehensive model to evaluate the efficiency of various RH intervention methods. Secondly, this paper collects the meteorological data in Nanjing at different time scales, from days to hours. Thirdly, a specific case study is carried out based on the model and data. The results show that dehumidification and heating can always reduce RH below the critical value under which the mold growth could be inhibited. However, the effects of ventilation are more sophisticated and depend upon the human occupancy, outdoor air temperature, and air change per hour (ACH). In certain unoccupied cases, the ventilation may be inappropriate and may continuously bring moisture outside into the indoor environment, which has adverse effects on mold suppression. In the occupied cases, the condition changes significantly because the human is deemed as an internal source of heat and moist. Special care should be exercised for occupied ventilation in order to determine the optimal ACH and appropriate outdoor temperatures. Finally, some guidance is given to prevent mold growth in the general area that suffers from the plum rain season.

Overview of surface to near-surface atmospheric profiles over selected domain during the QWeCI project

Assessing the evolution of surface to near-surface atmospheric fluxes is key to improving our understanding of their interactions, while further advancing climate applications. In this paper, an overview of the diurnal to seasonal evolution of some surface to near-surface atmospheric fluxes, coupled with their interactions, have been provided. Fluxes of downwelling and upwelling radiation ( $$SW_\downarrow$$ , $$SW_\uparrow$$ , $$LW_\downarrow$$ , $$LW_\uparrow$$ ), soil heat flux ( $$\Delta H$$ ), relative humidity (RH), rainfall (RR) and surface air temperature (T), measured from two different locations (Owabi and KNUST) and at a temporal resolution of 10 min, encompassing the quantifying weather and climate impact (QWeCI) Project period (2011–2013), were used to assess their relationship on diurnal to seasonal scales. First, diurnal assessments of the various profiles were performed. These provided information on the relatively active daytime, with the earth surface exposed to substantial $$SW_\downarrow$$ , initiating rising and sinking thermals which subsequently increased T and $$\Delta H$$ , with reductions in RH until few hours after midday, beyond which a reversal was observed. Also, $$\Delta H$$ from the vegetative terrain (Owabi) was found to be directed into the surface at daytime, and released from the sub-surface layer back into the atmosphere at night time, compensating the energy loss by $$LW_\uparrow$$ from the surface. Furthermore, rainfall (RR) in both locations were found to be generally convective and occurring mostly between 1500 GMT and 2300 GMT. The relationship between net radiation ( $$R_N$$ ) and RR is presently statistically unclear, although rainfall peaks were found to be occurring at low $$R_N$$ and relatively warmer T, accompanied by high RH. Thereafter, seasonal assessments were performed to capture the monthly-averaged diurnal variabilities in the measured surface to near-surface parameters. These showed heightened daytime T, $$\Delta H$$ and $$R_N$$ , coupled with relatively low RH within the dry seasons, and more reduced profiles within the monsoon season. Additionally, countrywide assessments were performed using ERA-5 datasets which showed similarities with the in situ data. However, convective rains over the domain were not fully resolved in ERA-5. Nonetheless, the findings of this study are essential to understanding surface energy balance processes in tropical, humid climates, which is important for various climate-impact modeling applications and policy formulations over the region.

Land–Ocean Shifts in Tropical Precipitation Linked to Surface Temperature and Humidity Change

A compositing scheme that predicts changes in tropical precipitation under climate change from changes in near-surface relative humidity (RH) and temperature is presented. As shown by earlier work, regions of high tropical precipitation in general circulation models (GCMs) are associated with high near-surface RH and temperature. Under climate change, it is found that high precipitation continues to be associated with the highest surface RH and temperatures in most CMIP5 GCMs, meaning that it is the “rank” of a given GCM grid box with respect to others that determines how much precipitation falls rather than the absolute value of surface temperature or RH change, consistent with the weak temperature gradient approximation. Further, it is demonstrated that the majority of CMIP5 GCMs are close to a threshold near which reductions in land RH produce large reductions in the RH ranking of some land regions, causing reductions in precipitation over land, particularly South America, and compensating increases over ocean. Recent work on predicting future changes in specific humidity allows the prediction of the qualitative sense of precipitation change in some GCMs when land surface humidity changes are unknown. However, the magnitudes of predicted changes are too small. Further study, perhaps into the role of radiative and land–atmosphere feedbacks, is necessary.

Decoupling of Autogenous Shrinkage and Tensile Creep Strain in High Strength Concrete at Early Ages

Appropriately interpreting the measured creep strain is critical for obtaining the actual creep strain, especially for high-strength concretes characterized by a low water/cement ratio (w/c) because autogenous shrinkage is significant in such concrete at early ages. To investigate the interaction between the autogenous shrinkage and tensile creep of concrete at early ages, various tests were conducted on concretes with water/cement (w/c) ratios =0.3 and 0.4, including basic tensile creep, strength, autogenous shrinkage, and the internal relative humidity (RH) measurements. The load was applied at the ages of 1 and 7 days at the stress/strength levels of 40% and 70%, respectively. It was found that the measured early-age tensile creep strain becomes negative due to the large autogenous shrinkage involved. The principle of superposition can be used for creep-autogenous shrinkage decoupling to obtain the actual basic tensile creep, as there is virtually no additional RH reduction or stress-induced shrinkage in concrete due to the sustained tensile load at early ages. An average tensile strength gain of 8.2% was found in specimens after sustained tensile loading compared to the unloaded specimens. An exponential function is proposed to quantify the autogenous shrinkage effect on the basic tensile creep in terms of specific creep/autogenous shrinkage ratio.

Effect of different heat ameliorating measures on the micro-climate of buffalo sheds during hot-dry summer

Present investigation studied the effect of heat ameliorating measures on micro-climate of sheds of Murrah buffalo heifers during hot dry summer. Buffalo heifers (24) were categorised in 4 groups (6 in each), viz. control (T0), cooling jacket (T1), cooling jacket+forced ventilation (T2) and sprinklers+forced ventilation (T3). Daily minimum and maximum and dry and wet bulb temperatures of both micro and macro-climate were measured at 10.00 AM and 2.00 PM of Indian Standard Time (IST) by using maximum and minimum and dry and wet bulb thermometer, respectively. Significant reduction in maximum temperature was observed in T3, T2 and T1 groups than control group. However, significantly higher minimum temperature was found in T0 group as compared to T3, T2 and T1 respectively. Relative humidity (RH) was significantly lower in T3 and T2 (65.67±0.48 and 65.97±0.53%, respectively) than T0 (68.51±0.56%) group at 10.00 AM whereas, at 2.00 PM significant reduction in RH was observed in T3, and T2 (55.31±0.51 and 57.20±0.62) than T0 (58.96±0.63%) group. During peak hot periods, significantly lower Temperature humidity Index (THI) was found in T3, T2 and T1 than T0 group. However, at 10.00 AM significant reduction in THI was found in T3 and T2 groups than T0 group. The findings of the present study indicated that forced ventilation along with sprinklers and cooling jacket had helped in protecting the animals from thermal stress under loose housing system during hot-dry summer.

Observed climatology and trend in relative humidity in the central and eastern Tibetan Plateau

AbstractMonthly surface relative humidity (RH) data for 71 stations in the Tibetan Plateau (TP) provided by the National Meteorological Information Center/China Meteorological Administration are compared with corresponding grid points from the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR hereafter) reanalysis. Mean climatologies, interannual variabilities, and trends calculated by the Mann‐Kendal method are analyzed during 1961–2013. The annual regional long‐term mean surface RH is 55.3%, with a clear maximum in summer (66.4%) and minimum in winter (44.9%). Compared with observations, NCEP/NCAR overestimates RH in all seasons, especially in spring (18.2%) and winter (17.8%). Mean annual regional surface RH has decreased by −0.23% decade−1 and even more rapidly in summer (−0.60% decade−1) and autumn (−0.39% decade−1). The reduction of surface RH is also captured by the NCEP/NCAR reanalysis at the surface, 400, 500, and 600 hPa. A particularly sharp reduction of RH since the mid‐1990s is evident in both data sets, in line with rapid warming over the plateau. This suggests that moisture supply to the plateau from the Arabian Sea and the Bay of Bengal is limited and that variability and trends of surface RH over the TP are not uniquely driven by the Clausius‐Clapeyron relationship.

Highly efficient production of Aspergillus niger amylase cocktail by solid-state fermentation using triticale grains as a well-balanced substrate

Triticale (Triticosecale, Wittmak) an important industrial crop, with high grain yield, containing high amounts of starch, proteins and also major and minor mineral elements, is not sufficiently utilized yet. The simultaneous production of ?-amylase and glucoamylase isoforms by Aspergillus niger on triticale grains, without any nutritive supplements, has been developed, optimized and scaled up 10 fold for the first time. The specific combination of examined effects led to the production of a novel glucoamylase isoform. Reduction of particle size, increase of oxygen availability and substrate height lead to increase of amylases production of 30%. Reduction of relative humidity from 65% to 30% increased glucoamylase production 2 times and ?-amylase production for 30%. Peak production of ?-amylase (158 U/g) and glucoamylase (170 U/g) were obtained in erlenmayers and in scaled-up trays. The obtained A. niger amylase cocktail was more efficient in raw starch hydrolysis from wheat flour, 29% more efficient in glucose formation and 10% more efficient in total reducing sugar formation, than commercially available amylase cocktail SAN Super 240L widely used in industry.

Characterization of Moisture Diffusion in Cured Concrete Slabs at Early Ages

The objective of this paper is to investigate the characterization of moisture diffusion inside early-age concrete slabs subjected to curing. Time-dependent relative humidity (RH) distributions of three mixture proportions subjected to three different curing methods (i.e., air curing, water curing, and membrane-forming compounds curing) and sealed condition were measured for 28 days. A one-dimensional nonlinear moisture diffusion partial differential equation (PDE) based on Fick’s second law, which incorporates the effect of curing in the Dirichlet boundary condition using a concept of curing factor, is developed to simulate the diffusion process. Model parameters are calibrated by a genetic algorithm (GA). Experimental results show that the RH reducing rate inside concrete under air curing is greater than the rates under membrane-forming compound curing and water curing. It is shown that the effect of water-to-cement (w/c) ratio on self-desiccation is significant. Lower w/c ratio tends to result in larger RH reduction. RH reduction considering both effect of diffusion and self-desiccation in early-age concrete is not sensitive to w/c ratio, but to curing method. Comparison between model simulation and experimental results indicates that the improved model is able to reflect the effect of curing on moisture diffusion in early-age concrete slabs.