Optimizing the postharvest storage conditions for high quality fresh sage

Risk effects of high and low relative humidity on allergic rhinitis: Time series study

Field observations in four pear orchards during 5 years from April to October indicated that days with uninterrupted wetness of variable length represented 83.9% of the total days studied. However, days with surface wetness interruptions and with high relative humidity (RH) (>/=90%) without wetness occurred with a frequency of 7.1 and 6.2%, respectively. Accordingly, the effect of interruption of 24-h wetness periods by dry periods of high or low RH on infections caused by Stemphylium vesicarium on pear was determined. Pear plants inoculated with conidia of S. vesicarium were exposed to a 12-h wet period followed by a dry period of variable length (0, 3, 6, 12, 18, or 24 h) and a second wet period of 12 h. The dry period consisted either of low (60%) or high (96%) RH. The infection process was irreversibly stopped under low RH during dry periods between wetness, but continued at high RH. The effect of high RH on disease severity in the absence of wetness was also determined. Pear plants inoculated with S. vesicarium were exposed to periods of variable length (3 to 24 h) either at high RH (96%) in the presence of wetness or at high RH (96%) without wetness. No infections were observed on plants incubated under high RH without wetness, indicating that conidia of S. vesicarium require the presence of a water film in the plant surface to develop infections on pear.

The quality of dried egg white with respect to functional properties can be affected by storage conditions. The effect of temperature and relative humidity (RH) on changes in colour and gelling properties in freeze-dried egg white (FDEW) during storage was investigated. The glass transition temperature (Tg ) of FDEW decreased with increasing % RH. The colour of FDEW stored at 60 °C was darker yellow than those at 40 and 25 °C, particularly at high % RH. RH had no effect on hardness and water-holding capacity (WHC) of gels made from FDEW stored at 25 °C for 1 week. However, hardness and WHC of gels from FDEW stored at higher temperatures; 40 °C, 48% RH and 60 °C, 11% RH dramatically increased. These results related to the differential scanning calorimeter thermograms which showed a broadening peak with lower enthalpy of protein denaturation. Moreover, the protein's SDS-PAGE pattern in the samples stored at high temperatures or RH levels showed protein aggregation. Storage of FDEW at high temperature and RH levels induced protein conformation changes. These have contributed to protein aggregation which affected the gelling properties of FDEW. © 2016 Society of Chemical Industry.

Effect of relative humidity on the uptake, translocation, and efficacy of glufosinate ammonium in wild oat ( Avena fatua)

Effects of relative humidity on the water repellency of fire-affected soils

In this study, an artificial neural network (ANN) approach was applied for modeling the relation between environmental variables and daily change in the Cleanness Index (ΔCI, a measure of performance loss due to soiling) of photovoltaic modules in the field in Doha, Qatar. The daily ΔCI was examined among a number of three-dimensional intervals of the daily mean of the environmental variables (i.e., the intervals of two environmental variables were presented on x and y dimensions, and average values of daily ΔCI on the third dimension), in order to qualitatively establish the relations that might help to develop improved PV soiling prediction models. Then, an ANN-based model was set up to simulate the relationship between daily ΔCI and environmental variables and compared with a linear regression model, both models using the same input variables, including present day and previous day environmental conditions, and cumulative exposure time. Strong interactions were observed among environmental variables PM10, relative humidity (RH) and wind speed (WS) regarding their effect on the daily ΔCI. Overall, higher PM10 resulted in more negative daily ΔCI (i.e. the module became more soiled), and this effect was more visible at low WS and RH levels, but at high WS (>4ms−1) and high RH (>65%) levels, PM10 had no significant (p>0.05, two tailed t-test) effect on daily ΔCI. Mostly, WS and RH determined how much airborne dust accumulates on the module surfaces and thereby affects the output of the PV modules. Higher WS typically favored more positive daily ΔCI when RH was low, but at higher RH levels (>50%) daily ΔCI was more likely to be negative with increasing WS. In fact, high RH levels were related to negative daily ΔCI only at higher WS levels (>2ms−1); at lower WS levels RH had no significant effect on daily ΔCI. These effects were apparently due to the deposition-resuspension mechanisms of dust accumulation on the PV panel surfaces. The ANN model performed significantly better in predicting daily ΔCIas well as cumulative CI than the linear model in term of R2 values and statistical error indexes. The previous day environmental conditions had a significant effect on the modeling outcome. The inclusion of the wind gustiness and cumulative exposure time also considerably improved the model prediction capability. The advantage of the ANN-based model is its simplicity, ease of data fitting and no requirement of an accurate mathematical model.

Evaporative heat loss from group-housed growing pigs at high ambient temperatures

Investigation of relative humidity effects on the response behavior of a pH indicator-based OWG vapor sensor

An integrated humidity sensor able to detect and measure a very low humidity concentration and higher relative humidity (RH) levels as well with the possibility of industrial application has been designed and fabricated using very large scale integration technology where thin porous Al2O3 film acts as humidity sensing material. The porous structure of Al2O3 has been obtained by anodic oxidation of a thin film of Al in sulfuric acid. During anodic oxidation, a few top atomic layers of Ta are also oxidized into Ta2O5 whose properties affect the normal sensing properties of Al2O3 and a better quality of sensor with higher sensitivity and speed is obtained. The gate insulator structure of the field-effect transistor is SiO2/Si3N4/Ta/Ta2O5/Al2O3. The device is basically an enhancement mode metal–oxide–semiconductor field-effect transistor. The drain current ID of the device is measured at constant gate and drain voltages at 25 °C and found to be sensitive up to less than ∼1 ppmv moisture concentration. The response time of the sensor in ppmv level is less than 1 s. The device is also found to be very sensitive at higher RH levels and shows a linear dependency on RH. The response and recovery times of the sensor are 2 and 6 s, respectively.

Abstract. The effect of relative humidity (RH) on secondary organic aerosol (SOA) formation from the photooxidation of m-xylene initiated by OH radicals in the absence of seed particles was investigated in a Teflon reactor. The SOA yields were determined based on the particle mass concentrations measured with a scanning mobility particle sizer (SMPS) and reacted m-xylene concentrations measured with a gas chromatograph–mass spectrometer (GC-MS). The SOA components were analyzed using a Fourier transform infrared (FTIR) spectrometer and an ultrahigh-performance liquid chromatograph–electrospray ionization–high-resolution mass spectrometer (UPLC-ESI-HRMS). A significant decrease was observed in SOA mass concentration and yield variation with the increasing RH conditions. The SOA yields are 14.0 %–16.5 % and 0.8 %–3.2 % at low RH (14 %) and high RH (74 %–79 %), respectively, with the difference being nearly 1 order of magnitude. Some of the reduction in the apparent yield may be due to the faster wall loss of semi-volatile products of oxidation at higher RH. The chemical mechanism for explaining the RH effects on SOA formation from m-xylene–OH system is proposed based on the analysis of both FTIR and HRMS measurements, and the Master Chemical Mechanism (MCM) prediction is used as the assistant. The FTIR analysis shows that the proportion of oligomers with C-O-C groups from carbonyl compounds in SOA at high RH is higher than that at low RH, but further information cannot be provided by the FTIR results to well explain the negative RH effect on SOA formation. In the HRMS spectra, it is found that C2H2O is one of the most frequent mass differences at low and high RHs, that the compounds with a lower carbon number in the formula at low RH account for a larger proportion than those at high RH and that the compounds at high RH have higher O : C ratios than those at low RH. The HRMS results suggest that the RH may suppress oligomerization where water is involved as a by-product and may influence the further particle-phase reaction of highly oxygenated organic molecules (HOMs) formed in the gas phase. In addition, the negative RH effect on SOA formation is enlarged based on the gas-to-particle partitioning rule.

Several citrus cultivars including `Marsh' grapefruit (Citrus paradisi Macf.) and `Fallglo' tangerine [Bower citrus hybrid (C. reticulata Blanco × C. reticulata × C. paradisi) × Temple tangor (C. reticulata × C. sinensis L. Osbeck)] are prone to develop postharvest peel pitting at nonchilling temperatures. This disorder is characterized by depressions in flavedo that ultimately affect oil glands. Although the fundamental cause for this disorder has not been well defined, increasing evidence indicates that alteration in peel water status during postharvest handling of fruit plays a major role. `Fallglo' tangerines developed postharvest peel pitting when transferred from low (30%) to high (90%) relative humidity (RH) storage. To determine the number of hours of dehydration prior to storage at high RH sufficient to induce peel pitting in `Marsh' grapefruit and `Fallglo' tangerines, fruit were exposed to low RH conditions for increasing periods of time and then washed, coated with commercial shellac-based wax, and stored at high RH. Only 2 hours of low RH storage were sufficient to induce peel pitting in `Fallglo' and `Marsh' after transfer to high RH. The severity of pitting in `Fallglo' tangerines was greater than in `Marsh' grapefruit. Weight loss of fruit at the end of low RH storage and peel pitting after 3 weeks of storage at high RH were significantly correlated. RH conditions in the field at the time of harvest affected susceptibility to peel pitting in both cultivars. Peel pitting was more severe when fruit were harvested at low field RH than high field RH when followed by treatments that induce peel pitting. The data suggest that harvesting susceptible cultivars at high RH, and minimizing exposure to low RH after harvest, could reduce the commercial impact of postharvest peel pitting.

Combined effects of high relative humidity and ultraviolet irradiation: Enhancing the production of gaseous NO2 from the photolysis of NH4NO3

To extend the postharvest storage life of broccoli samples (Brassica oleracea L. var. italica), an exogenous application of citric acid (CA), salicylic acid (SA), and putrescine (PUT) was tested in multiple combinations (0.5 and 1 mM) at 4 ± 0.5°C and 90 ± 5% relative humidity (RH) for 21 days (d). The weight loss (WL), respiration rate (RR), total soluble solids (TSS), pH, color (L*, a*, b*, chroma, and hue angle), proximate and mineral contents, phenolic and flavonoid contents, and other biochemical properties of the treated and untreated broccoli samples were evaluated throughout the storage duration. The lowest WL was observed when exposed to 0.5 mM of PUT. 1 mM CA and PUT treatments were affected by RR, depending on storage conditions. The lowest TSS content was observed in broccoli samples treated with 0.5 mM CA among all treatments. The chroma value of the samples was preserved by the 0.5 mM SA treatment. The most abundant element in broccoli samples was potassium in the control application, followed by a 1 mM SA treatment. In addition, the protein content was the highest in the 1 mM PUT treatment. The highest vitamin C was determined in the 1 mM CA treatment, and the most abundant vanillic acid was found in broccoli exposed to the 0.5 mM and treatment. Glucose content was determined at the lowest level in the 0.5 mM SA treatment, while higher increases occurred in other treatments. In terms of these findings, 1 mM CA, 1 mM SA, and 1 mM PUT delay WL, RR, and color degradation and prolong the storage life of broccoli samples stored at 4 ± 0.5°C. It was concluded that the biochemical content, fresh weight, and green color of broccoli samples throughout postharvest and storage can be maintained longer by exogenous application of these natural compounds. Therefore, we recommend 1 mM PUT and 1 mM CA treatments to maintain the quality of broccoli by minimizing losses in morphological properties, mineral, and biochemical compositions during postharvest storage.

Fomites can serve as routes of transmission for both enteric and respiratory pathogens. The present study examined the effect of low and high relative humidity on fomite-to-finger transfer efficiency of five model organisms from several common inanimate surfaces (fomites). Nine fomites representing porous and nonporous surfaces of different compositions were studied. Escherichia coli, Staphylococcus aureus, Bacillus thuringiensis, MS2 coliphage, and poliovirus 1 were placed on fomites in 10-μl drops and allowed to dry for 30 min under low (15% to 32%) or high (40% to 65%) relative humidity. Fomite-to-finger transfers were performed using 1.0 kg/cm(2) of pressure for 10 s. Transfer efficiencies were greater under high relative humidity for both porous and nonporous surfaces. Most organisms on average had greater transfer efficiencies under high relative humidity than under low relative humidity. Nonporous surfaces had a greater transfer efficiency (up to 57%) than porous surfaces (<6.8%) under low relative humidity, as well as under high relative humidity (nonporous, up to 79.5%; porous, <13.4%). Transfer efficiency also varied with fomite material and organism type. The data generated can be used in quantitative microbial risk assessment models to assess the risk of infection from fomite-transmitted human pathogens and the relative levels of exposure to different types of fomites and microorganisms.

Water stress affects on cell membrane lipid oxidation and calcification of chestnut (Castanea mollissima Bl.)