Influence of Relative Humidity on Elastic Modulus of Bamboo Bundle

Relative humidity (RH) can have a significant impact on bamboo products, leading to issues such as swelling, shrinking, and even cracking. Unfortunately, these effects are often difficult to detect in bamboo bundles. This research aims to investigate how RH affects the moisture expansion coefficient (β) of bamboo bundles. Samples from the stem of the Dendrocalamus genus were dried in an oven at 105 °C until they reached a stable weight. The samples were then hand-pulled and cut to create cross-sections with areas ranging from 0.06 mm 2 to 0.09 mm 2 and a length of 60 mm. The expansion coefficient of the bamboo bundles was measured using a tensile test, following the ASTM D3379 standard. This was conducted at a constant temperature of 27 °C and a force of 10 N in a controlled chamber with RH levels between 50% and 85% for a full day, with five replicates for accuracy. The results indicate that the strain in bamboo bundles is influenced by both relative humidity (RH) and tensile load. When the RH ranges from 85% to 50%, the bamboo bundles tend to stretch under tensile load. However, when the RH drops to 50% without tensile load, the bundles can return to their original shape. This suggests that while the initial changes in strain may be small, bamboo bundles gradually experience increased strain over time, and prolonged use could result in more significant alterations. Another important factor to consider when using bamboo bundles is the effect of changes in relative humidity (ΔRH) on the average value of β. Indeed, bamboo bundles need time to absorb or release moisture as the surrounding environment changes. The average value of β tends to decrease dramatically in an exponential decay pattern. When ΔRH exceeds 5% in both charge and discharge conditions, the average value of β can be considered equal and constant, as it becomes extremely small and negligible. However, at ΔRH levels higher than 20%, the average value of β converges to 1.5 x 10-4 (%RH)-1, indicating that the bamboo bundles have already adapted to the surrounding humidity. Therefore, it is crucial to carefully assess application areas with rapid humidity fluctuations when using bamboo bundles to prevent potential damage during use.

The concentration of air pollutants in ambient air is governed by the meteorological parameters such as atmospheric wind speed, wind direction, relative humidity, and temperature. This study analyses the influence of temperature and relative humidity on ambient SO2, NOx, RSPM, and SPM concentrations at North Chennai, a coastal city in India, during monsoon, post-monsoon, summer, and pre-monsoon seasons for 2010-11 using regression analysis. The results of the study show that both SO2 and NOx were negatively correlated in summer (r2=0.25 for SO2 and r2=0.15 for NOx) and moderately and positively correlated (r2=0.32 for SO2 and r2=0.51 for NOx) during post-monsoon season with temperature. RSPM and SPM had positive correlation with temperature in all the seasons except post-monsoon one. These findings indicate that the influence of temperature on gaseous pollutant (SO2 & NOx) is much more effective in summer than other seasons, due to higher temperature range, but in case of particulate, the correlation was found contradictory. The very weak to moderate correlations existing between the temperature and ambient pollutant concentration during all seasons indicate the influence of inconstant thermal variation in the coastal region. Statistically significant negative correlations were found between humidity and particulates (RSPM and SPM) in all the four seasons, but level of correlation was found moderate only during monsoon (r2=0.51 and r2=0.41) in comparison with other three seasons and no significant correlation was found between humidity and SO2, NOx in all the seasons. It is suggested from this study that the influence of humidity is effective on subsiding particulates in the coastal region.

Mould growth on building materials under low water activities. Influence of humidity and temperature on fungal growth and secondary metabolism

Air humidity is one of the main factors affecting the characteristics of semiconductor gas sensors, especially at low measurement temperatures. In this work we analyzed the influence of relative humidity on sensor properties of the hybrid materials based on the nanocrystalline SnO2 and In2O3 and Ru (II) heterocyclic complex and verified the possibility of using such materials for NO (0.25–4.0 ppm) and NO2 (0.05–1.0 ppm) detection in high humidity conditions (relative humidity (RH) = 20%, 40%, 65%, 90%) at room temperature during periodic blue (λmax = 470 nm) illumination. To reveal the reasons for the different influence of humidity on the sensors’ sensitivity when detecting NO and NO2, electron paramagnetic resonance (EPR) spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) investigations were undertaken. It was established that the substitution of adsorbed oxygen by water molecules causes the decrease in sensor response to NO in humid air. The influence of humidity on the interaction of sensitive materials with NO2 is determined by the following factors: the increase in charge carrier’s concentration, the decrease in the number of active sites capable of interacting with gases, and possible substitution of chemisorbed oxygen with NO2− groups.

Electrospinning of uniform nanofibers of Polymers of Intrinsic Microporosity (PIM-1): The influence of solution conductivity and relative humidity

In this paper, the working principle of static protective clothing and its testing method of quantity of electric charge are introduced, and the influence of temperature and relative humidity on the quantity of electric charge (qe) of static protective clothing is studied by measuring qe of different clothing samples. The result shows that temperature and relative humidity can influence qe of static protective clothing to some extent and the influence of relative humidity is bigger than that of temperature. According to experimental results, the relationship of qe and relative humidity and temperature was analysed, and the safety boundary of quantity of electric charge is discussed. In order to reduce the occurrence of electrostatic accidents and ensure safe production and operation of petrochemical industry, some suggestions on choosing and using of static protective clothing are given for guaranteeing its static protective performance.

The present study examined the influence of atmospheric humidity on the absorption of the mineral nutrients (potassium, calcium, magnesium and manganese) for 28 days after seeding, using rice plants cultivated by water culture. The following results were obtained : 1. The amounts of K and Ca absorbed were greater under the conditions of a high humidity than those under a low one. The amounts of Mg and Mn absorbed, on the other hand, were lower under the condition of high humidity (Fig. 2). 2. The atmospheric humidity had little effect on the content of K in the leaf blade. However, the contents of Ca, Mg and Mn were strongly influenced : the lower the atmospheric humidity, the higher the contents of Ca, Mg and Mn accumulated in the leaf blade (Table 2, Fig. 3). 3. The content of K in the leaf blade was not influenced by the transpiration rate. However, the contents of Ca, Mg and Mn were strongly affected, becoming higher with an increase in the transpiration rate (Fig. 4). Finally, the absorption of K is increased with higher dry matter production under the condition of high humidity. On the other hand, the absorption of Ca, Mg and Mn are increased with higher transpiration under the condition of low humidity.

Apple is an important fruit worldwide with nutrition and a huge market value. However, due to the mechanical damage during its handling after the harvest, millions of dollars are lost in the apple industry. Bruise (subcutaneous) is a mechanical damage caused to a fruit without any tearing of the fruit-skin. It could be caused by a mechanical impact, vibration, or compression which the fruit might come across during its handling after the harvest. It results in local degradation of the flesh tissue with browning effect with time. Normally, apple bruises take place beneath the peel and are difficult to detect by either visual or automatic color sorting. Thermal imaging offers a promising, contact-free, alternative technique for bruise detection in apples. Thermal imaging technique measures infrared energy emitted from the object surface which is converted into a thermal map called a thermogram. In the literature, there has been some work done on the influence of temperature and relative humidity of the surrounding on bruise susceptibility of fruits. In this paper, the influence of relative humidity in bruise development on apple was investigated applying thermal imaging technique. To accomplish this, two batches of healthy, almost same-sized, yellow and green apples with ten apples per batch were considered. The apples were subjected to a mechanical impact by dropping them from a constant height ensuring the fruit skin is not torn by the impact and the impact is same is for all the apples. Then, they were thermal imaged with the focus on their bruises. They were kept and observed at two different temperatures and relative humidity. The first set involved the relative humidity of 40–43% with room conditions whereas the second one involved the relative humidity of 80%–82% in the freezer compartment of a domestic refrigerator. For all the trials, the same condition was maintained for the fruits throughout the three-day observation. At the end of stipulated observation period, the fruits were thermal imaged to capture the bruise development for the different relative humidity levels for two different temperatures. The observation was repeated for three times to obtain the repeatability. The results show that the bruise development is faster for the higher relative humidity than for the lower one. This could be due to the lower transpiration rate of water from the fruits at higher relative humidity. Also, the water potential under the bruised skin decreases faster for lower relative humidity condition which results in decreased bruise development.

The influence of temperature, relative humidity, and storage time on the production of Ochratoxin A by the fungus Aspergillus niger in dry parchment coffee was determined under controlled laboratory conditions. Additionally, the roasting curve that would achieve maximum reduction of OTA concentration in roasted coffee was evaluated. The objective was to establish strategies to reduce the risk of product contamination by this mycotoxin in coffee farms and its presence in coffee ready for consumption. For the analysis of the influence of temperature, relative humidity, and storage times on OTA production, sterilized coffee samples incubated with the A. niger strain were used. To obtain the roasting curves, coffee samples stored for 15 days at a temperature of 23 °C and relative humidity of 60% were employed. The OTA concentration of each study samples was quantified by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). The results obtained enabled: (1) The understanding of the conditions of temperature, relative humidity, and storage time that favor the production of the toxin by A. niger, thus allowing the development of coffee storage protocols that reduce grain contamination by this toxin, as it was found that increases in storage time and decreases in temperature and relative humidity to certain values are associated with increases in OTA concentration in the DPC. (2) Identifying the roasting curve whereby the coffee was subjected to temperatures from 180 °C to 208.8 °C for 11.23 min, achieving an OTA degradation of 76.4%. This curve serves as a guide for the adjustment of the temperatures and roasting times around the variables present in the process, achieving different roasting profiles, a significant reduction of OTA without affecting the quality of the coffee, and facilitating different chemical, physical, and organoleptic characteristics that can accommodate consumers’ tastes and ensure a safe beverage.

To investigate the influence of storage relative humidity (RH) on the aerosolisation efficiency and tribo-electrification of carrier based dry powder inhaler (DPI) formulations using the next generation impactor (NGI) in vitro methodology and the electrostatic low pressure impactor (ELPI). Micronised salbutamol (d (0.5) 1.48 +/- 0.03 microm) was blended with 63-90 microm sieve fractioned alpha-lactose monohydrate carrier and stored at a range of humidities (0-84% RH). The aerosolisation efficiency after storage for 24 h periods was investigated using the NGI. The same experiment was conducted using the ELPI, with corona charger switched off, to measure the net charge vs. mass deposition profile. Significant variations in the aerosolisation efficiency of the formulation were observed with respect to storage RH. In general, the fine particle fraction aerosol performance measured by NGI and ELPI (fraction with mass median aerodynamic diameter <4.46 and 4.04 microm, respectively) followed a positive parabola with aerosol performance increasing over the range 0-60% RH before decreasing >60% RH. Analysis of the ELPI charge data suggested that the micronised salbutamol sulphate had an electronegative charge when aerosolised from lactose based carriers, which was most electronegative at low RH. Increased storage RH resulted in a reduction in net charge to mass ratio with the greatest reduction at RH >60%. The aerosol performance of this binary system is dependent on both electrostatic and capillary forces. The use of the ELPI allows a degree of insight into how these forces affect formulation performances after storage at different RH.

Improved numerical model for steel reinforcement corrosion in concrete considering influences of temperature and relative humidity

Influence of humidity on the fretting wear of self-mated tetragonal zirconia ceramics

The influence of relative humidity and thermal acclimation on the survival of adult grain beetles in cooled grain

The influence of relative air humidity on the surface charge decay on epoxy resin insulators initially charged by DC corona and on their surface resistivity is investigated at room temperature. It has been observed, that surface resistivity of the epoxy resin insulators decreases significantly at higher relative humidity. Thus, at higher relative humidity surface charge decay is dominated by electric conduction along the insulator surface. This effect has been verified by both, measurement and simulation of the surface charge decay.

In this paper, the influence of ambient temperature and relative air humidity on the hydrophobicity transfer property of HTV and RTV silicone rubber (SR) is investigated. The static contact angle on polluted HTV-SR samples and plates with RTV coating was measured while being stored at different temperature and relative humidity. It has been found that the transfer characteristics on HTV-SR exhibit a saltus between 50°C and 55°C. The results further show that the influence of relative humidity is related with the hygroscopicity of soluble and non-soluble substances in pollutants on the surface.