Search results for " Humidity"
showing 10 items of 178 documents
Heterogeneous Interactions between Gas-Phase Pyruvic Acid and Hydroxylated Silica Surfaces: A Combined Experimental and Theoretical Study
2019
The adsorption of gas-phase pyruvic acid (CH3COCOOH) on hydroxylated silica particles has been investigated at 296 K using transmission Fourier transform infrared (FTIR) spectroscopy and theoretical simulations. Under dry conditions (<1% relative humidity, RH), both the trans-cis (Tc) and trans-trans (Tt) pyruvic acid conformers are observed on the surface as well as the (hydrogen bonded) pyruvic acid dimer. The detailed surface interactions were further understood through ab initio molecular dynamics simulations. Under higher relative humidity conditions (above 10% RH), adsorbed water competes for surface adsorption sites. Adsorbed water is also observed to change the relative populations …
Comparison of IAGOS in-situ water vapour measurements and ECMWF ERA-Interim Reanalysis data
2019
Abstract. Cirrus clouds and their potential formation regions, so-called ice-supersaturated regions (ISSRs) occur frequently in the tropopause region. It is assumed that ISSRs and cirrus clouds can change the tropopause structure by diabatic processes, driven by latent heating due to phase transition and interaction with radiation. For many research questions a three-dimensional picture including a sufficient temporal resolution of the water vapour fields in the tropopause region is required. This requirement is fulfilled nowadays by reanalysis products such as the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis. However, for a meaningful investigation of w…
Coping with the climate: cuticular hydrocarbon acclimation of ants under constant and fluctuating conditions
2018
International audience; Terrestrial arthropods achieve waterproofing by a layer of cuticular hydrocarbons (CHCs). At the same time, CHCs also serve as communication signals. To maintain waterproofing under different climate conditions, insects adjust the chemical composition of their CHC layer, but this may affect the communication via CHCs. The detailed acclimatory changes of CHCs and how these influence their physical properties are still unknown. Here, we studied acclimation in two closely related ant species with distinct CHC profiles, Myrmica rubra and Myrmica ruginodis, in response to constant or fluctuating temperature and humidity regimes. We measured how acclimation affected CHC co…
Arabidopsis mutant dnd2 exhibits increased auxin and abscisic acid content and reduced stomatal conductance
2019
Arabidopsis thaliana cyclic nucleotide-gated ion channel gene 4 (AtCNGC4) loss-of-function mutant dnd2 exhibits elevated accumulation of salicylic acid (SA), dwarfed morphology, reduced hypersensitive response (HR), altered disease resistance and spontaneous lesions on plant leaves. An orthologous barley mutant, nec1, has been reported to over-accumulate indole-3-acetic acid (IAA) and to exhibit changes in stomatal regulation in response to exogenous auxin. Here we show that the Arabidopsis dnd2 over-accumulates both IAA and abscisic acid (ABA) and displays related phenotypic and physiological changes, such as, reduced stomatal size, higher stomatal density and stomatal index. dnd2 showed i…
The effect of buffer strip width and selective logging on riparian forest microclimate
2019
Riparian forests have cool and humid microclimates, and one aim of leaving forested buffer strips between clear-cut areas and streams is to conserve these microclimatic conditions. We used an experimental study set up of 35 streamside sites to study the impacts of buffer strip width (15 or 30 m) and selective logging within the buffer strips on summer-time air temperature, relative air humidity and canopy openness 12 years after logging. The buffer strip treatments were compared to unlogged control sites. We found that 15-meter buffer strips with or without selective logging and 30-meter buffer strips with selective logging were insufficient in maintaining temperature, relative humidity and…
ENVIRONMENTAL FACTORS IMPACT AND INCIDENCE OF PARASITISM OF PSYLLAEPHAGUS BLITEUS RIEK (HYMENOPTERA ENCYRTIDAE) ON POPULATIONS OF GLYCASPIS BRIMBLECO…
2018
The red gum lerp psyllid, Glycaspis brimblecombei Moore (Hemiptera, Aphalaridae), is an Australian native sap-sucking insect pest of eucalypts that has been first reported for the West Palaearctic Region in 2008 and, in 2010, it has been found also in Italy. Subsequently its primary parasitoid, Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae), was also detected within the main European and North African infested areas, where no release of the parasitoid was ever performed. This study, carried out in 30 Eucalyptus camaldulensis plantations located along the coast, on the hills and the mountains in Mediterranean climatic areas of Sicily (Italy), aimed to determine the influence of environ…
Effects of gellan-based coating application on litchi fruit quality traits
2018
The use of gellan-based coating formulation on litchi (Litchi chinensis Sonn. ‘Wai Chee’) fruit was investigated in order to determine its ability to improve color conservation and to maintain the overall quality. Fruits were treated with gellanbased coating (0.5% w/v) and glycerol (3% w/v) after dipping in ascorbic acid (1.5% w/v) and then stored at 5°C and 90% relative humidity for 15 days. Changes in peel color, soluble solid content, tritatable acidity, weight loss, antioxidant activity and phenolic content, were measured. Formulations containing gellan-based coating exhibited slightly improved water barrier properties and showed their active role in maintaining color characteristics an…
Design and Implementation of a Smart System to Control Aromatic Herb Dehydration Process
2020
Drying is a process aimed at reducing the water content in plant materials below a limit where the activity of microbes and decomposing enzymes deteriorate the quality of medicinal and aromatic plants. Today, the interest of consumers towards medicinal and aromatic herbs has registered a growing trend. This study aims at designing a low-cost real-time monitoring and control system for the drying process of aromatic herbs and evaluating drying efficacy on the microbial community associated with the studied herbs. Hot-air drying tests of sage and laurel leaves were carried out in a dryer desiccator cabinet at 40 °
Influence d'humidité de l'air sur le séchage d'une goutte déposée sur une surface solide et sur la destruction microbienne.
2017
International audience; This study was carried out in order to develop experimental methodology using a camera to monitor the evolution of the surface of a liquid droplet deposited on a solid surface composed of polypropylene. The droplet was exposed to various ambient relative humidity conditions (11.3%, 43.2%, 68.9% and 75.5%). Two types of liquid were investigated: distilled water and water containing nutritive substances (salmon “juice”). At 11.3% relative humidity, it takes 40% longer to evaporate a water droplet (initial weight 0.36 g, volume 360 μL, radius 6.5 × 10−3 m) than a salmon “juice” droplet (3.66 h for distilled water, 2.83 h for salmon “juice”). In the case of the distilled…
Optimized tableting for extremely oxygen-sensitive probiotics using direct compression
2018
International audience; Faecalibacterium prausnitzii was previously recognized for its intestinal anti-inflammatory activities and it has been shown less abundant in patients with chronic intestinal diseases. However, the main problems encountered in the use of this interesting anaerobic microorganism are firstly its high sensitivity to the oxygen and secondly, its ability to reach the large intestine alive as targeted site. The aim of this study was to investigate the effect of direct compression on the viability of this probiotic strain after different compression pressure and storage using three different excipients (MCC, HPMC and HPMCP). The effect of compression process on cell viabili…