Enhanced air filtration performance under high-humidity condition through electrospun membranes with optimized structure

The separation stability under high-humidity is significant in practical applications for air filters.Herein,hydrophobic polyvinyl chloride(PVC)nanofiber filters with bead-on-string structure are designed to steadily remove particle matter under high relative humidity of 90%-95%.The developed hydrophobic filters possess comparable separation performance with the hydrophilic one,but greatly enhanced stability.After the introduction of beadon-string structure,the filtration performance can be furtherly improved due to the formed large cavities and hydrophobicity.Such hydrophobic PVC filters can be promising candidates for air purification in practical applications especially in wet seasons.

Methyl functionalization of trimesic acid in copper-based metal-organic framework for ammonia colorimetric sensing at high relative humidity

Exhaled ammonia(NH_(3))can be used as a crucial biomarker of kidney and liver diseases.However,the high humidity in the detection conditions remains a challenge for accurate detection by gas sensors.Herein,a copper-based metal-organic framework(CH_(3)-Cu-BTC)with methyl(CH_(3)^(-))functionalization of trimesic acid was synthesized for NH_(3) colorimetric sensing.The CH_(3)-Cu-BTC exhibited a strong response for 5 ppm NH_(3) with high selectivity under high relative humidity(75%RH).Density functional theory(DFT)simulations indicated that the NH_(3) molecules interacted more strongly with CH_(3)-Cu-BTC than H_(2)O molecules did,and the corresponding color switching was attributed to the lone-pair electron in NH_(3) changing the coordination environment of Cu^(2+)ions,leading to an obviously visible color switching response from ruby green to blue.Based on the tailor-made pore chemistry,the precise detection of trace amounts of NH_(3) in exhaled air was realized through functionalized MOF materials.The strategy used in this study not only offers a new pathway for the rapid detection of low concentration NH_(3) under humid conditions,but also shows a method for early respiration diagnosis of kidney and liver diseases.

Effects of high temperature and high relative humidity drying on moisture distribution,starch microstructure and cooking characteristics of extruded whole buckwheat noodles

Drying is a key step in starch noodle production.The effects of high temperature(60,70,80°C)and high relative humidity(65%,75%,85%)drying(HTHD)on the moisture distribution,starch microstructure and cooking characteristics of extruded whole buckwheat noodles were investigated.Compared to the conventional hot-air drying(CHAD)at 40°C,the increase in drying temperature(60–80°C)and the decrease in relative humidity(85%–65%)significantly improved drying efficiency of the extruded noodles.By adjusting drying temperature and relative humidity,the rate of moisture migration in noodles and phase transition of starch could be appropriately controlled.The optimum drying parameters(T70H75,70°C drying temperature and 75%relative humidity)showed smooth and dense network structure,resulting in the lowest cooking loss(6.61%),broken rate(0%),highest hardness(1695.17 g)and springiness(0.92).However,the total flavonoid content(TFC)and the total phenolic content(TPC)reduced by 6.81%–28.50%and 7.19%–53.23%in contrast to CHAD,and the color of buckwheat noodles became darker through HTHD.These findings showed the potential of HTHD for increasing drying efficiency and improving buckwheat noodle quality.The appropriate drying parameters could maintain a balanced relationship between moisture migration in noodles and phase transition of starch,which resulted in better cooking quality for extruded whole buckwheat noodles.Such a study is valuable for regulating the process conditions of buckwheat-based foods and promoting its commercial utilization.

Acetone sensors for non-invasive diagnosis of diabetes based on metal-oxide-semiconductor materials

In recent years, clinical studies have found that acetone concentration in exhaled breath can be taken as a characteristic marker of diabetes. Metal-oxide-semiconductor (MOS) materials are widely used in acetone gas sensors due to their low cost, high sensitivity, fast response/recovery time, and easy integration. This paper reviews recent progress in acetone sensors based on MOS materials for diabetes diagnosis. The methods of improving the performance of acetone sensor have been explored for comparison, especially in high humidity conditions. We summarize the current excellent methods of preparations of sensors based on MOSs and hope to provide some help for the progress of acetone sensors in the diagnosis of diabetes.

Physiological responses of people in working faces of deep underground mines

The research studied the influences of high temperature, high pressure, high humidity, noise and other harmful factors in mining conditions on the people health and safety, and investigated the impacts of confined environmental on human physiology factors, including temperature, humidity, noise, pressure,toxic and harmful gases in terms of environmental characteristics in underground mines and an artificial intelligence system for simulation of the environment in a confined space of deep mines. Our results show that the systolic pressure, diastolic pressure, mean pressure, heart rate, respiratory rate, typing test speed and memory level percentage are negatively correlated with temperature value, and positively correlated with humidity value; the human temperature and weight are positively correlated with temperature value, and negatively correlated with humidity value. This research lays the foundation for the study of interaction between the deep confined space environment and safety behavior.

PF/EP/Nano-SiO_2 Composite Paint for Resistor

Phenolic resin(PF) and nano-SiO2 were used to improve the curing property and high humidity resistance of epoxy resin (EP) and methyl nadic anhydride (MNA) resistor paint, respectively. Hydrogen bonds, formed between phenolic resin and nano-SiO2 in alcohol, made nano-SiO2 disperse easily in EP/MNA paint through phenolic resin without being treated by supersonic vibration. When the mass ratio of PF to EP in paint is 3:7, the formed composite paint film can be cured in 2 min at 170 ℃ . When the mass ratio of nano-SiO2 to PF in paint is 3:100, the property of high humidity resistance of the composite paint is the best, meeting the requirement of varying ratio of resistance less than 0.1% after experiment on high humidity resistance. SEM analysis shows the surface of the composite paint film is smooth, glassy, tight and homogeneous, without acicular air holes.

Low-temperature combined with high-humidity thawing improves the water-holding capacity and biochemical properties of Portunus trituberculatus protein

This study compared the effects of conventional thawing methods(water immersion thawing(WIT,(25±1)℃),natural air thawing(AT,(25±1)℃,relative humidity(RH(65±2)per cent),refrigerator thawing(RT,4℃,RH(80±2)per cent)and low-temperature(LT)combined with high-humidity thawing LT,-1℃to 1℃(LT-1-1),2-4℃(LT2-4),5-7℃(LT5-7)and 8-10℃(LT8-10),RH>95 per cent)on the water-holding capacity,lipid oxidation and biochemical properties of Portunus trituberculatus(P.trituberculatus)myofibrillar protein.The results showed that WIT and AT significantly decreased the water-holding capacity while dramatically increasing lipid oxidation,protein oxidation and degeneration,resulting in serious P.trituberculatus quality deterioration.High humidity was beneficial for P.trituberculatus\.ha\A/\ng.The thawing time of P.trituberculatus under the conditions of LT2-4 was only 39.39 per cent of that of conventional air thawing at 4℃(RT),and the LT2-4 samples not only maintained better water-holding capacity but also had an obviously reduced degree of lipid oxidation,protein oxidation and denaturation.Thawed samples LT2-4 and LT5-7 provided better maintenance of P.trituberculatus quality than the LT-1-1 and LT8-10 samples.The best quality was exhibited after thawing at 2-4℃.The levels of thiobarbituric acid reacting substances,carbonyl content and surface hydrophobicity observably decreased in these samples,while the total sulfhydryl contents dramatically increased compared to those of conventionally thawed samples,indicating lower lipid oxidation and protein oxidation.Moreover,the Ca2+-ATPase activity of the sample thawed at 2-4℃(2.06 μmol Pi/mg prot/h)was markedly higher than that of samples subjected to WIT and AT.The product qualities observed after thawing at-1℃to 1℃,5-7℃and 8-10℃under LT were comparable to that observed by RT.Considering its thawing efficiency and product quality,LT is a suitable method for the thawing of P.trituberculatus,and the ideal thawing conditions were LT at 2-4℃.

Synthesis of Modified Epoxy Resin Undercoat for Resistor by Nano-SiO_2

A kind of undercoat for resistor with high temperature and humidity resistance was obtained by modifying epoxy resin with proper nano-SiO2 added at 80℃. The structure, thermal stability, humidity resistance, and morphological characteristics of the modified epoxy resin undercoat were studied by electrical tests, infrared spectra （IR） analysis, and scanning electron microscopy （SEM）. The results show that more compact and steady inter-crosslinked network structures are formed in the modified epoxy resin undercoat added with nano-SiO2, which greatly improves the performance of modified epoxy resin undercoat. The undercoat with nano-SiO2 of about 2. 71%, kept for six months at room temperature without flocculating and aggregating, is of good stability, and the surface of painted resistor is uniform, tight and without air holes on it. The varying ratio of resistance with such undercoat painted is less than one in a thousand after high temperature and humidity resistance tests.

Effect of temperature and moisture on the luminescence properties of silicone filled with YAG phosphor

In order to determine the environmental effects on the luminescence properties of a phosphor layer for high-power light emitting diodes, a high humidity and temperature test （85℃/85%RH） and a thermal aging test （85℃） were performed on silicone/YAG phosphor composites. The luminescence properties of silicone/phosphor composites are monitored by a fluorescence spectrometer. The results show that high temperature could result in an increase in conversion efficiency of composites during the early aging stage and red shift of YAG phosphor; and high humidity could result in a significant decrease in conversion efficiency of composites while having a small influence upon the optimal excitation wavelength of the YAG phosphor.

Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature

Pericarp browning is the major cause of deterioration of harvested litchi fruit.Water loss plays a role in pericarp browning of litchi fruit.This study investigated the effects of humidification with dry fog on pericarp browning and quality of litchi fruit stored at low temperature.Litchi fruit were stored in a non-humidified cold chamber(control)or in a humidified cold room using Tabor atomizer system that generated 95%relative humidity(RH)without depositing water on the fruit surface at 4℃.Control fruit stored in cold room without added humidity underwent rapid weight loss,accompanied by severe pericarp browning after 25 d of storage.However,slight weight loss and no obvious pericarp browning were found in humidified-fruit.Moreover,humidification maintained well the integrity of cell membrane and inhibited polyphenol oxidase activity during early storage.In addition,respiration rate was obviously inhibited in humidified-fruit compared with control fruit.This study might provide a convenient approach to reduce pericarp browning of harvested litchi fruit by humidifying the fruit using the Tabor atomizer at low temperature instead of packaging with film.