Search results for "Relative Humidity"

Organic solvents vapor pressure and relative humidity effects on the phase transition rate of α and β forms of tegafur.

2011

The objective of this work was to investigate the relative humidity (RH) and solvent vapor pressure effects on the phase transition dynamics between tegafur polymorphic forms that do not form hydrates and solvates. The commercially available α and β modifications of 5-fluoro-1-(tetrahydro-2-furyl)-uracil, known as the antitumor agent tegafur, were used as model materials for this study. While investigating the phase transitions of α and β tegafur under various partial pressures of methanol, n-propanol, n-butanol, and water vapor, it was determined that the phase transition rate increased in the presence of solvent vapors, even though no solvates were formed. By increasing the relative air h…

Visibility forecast in the phase of pre-condensation

1969

The effect on visibility of the swelling of aerosol particles due to increasing humidity is studied. The swelling can be described by r(f)/r (0) = (1 - f ) ?1/? where r ( f ) = particle radius at relative humidity f and ? = const ? 4 on the average. The visibility variation is expressed as V(f)/V(f 0 ) = [(1 - f )/(1 - f 0 )] V * ? 1)/? where V * = exponent of the aerosol size distribution ? 3 on the average. The last formula allows to compute the standard visual range V(f) at relative humidity f from the present standard visual range V(f 0 ) at present relative humidity f 0 . DOI: 10.1111/j.2153-3490.1969.tb00469.x

Meridional gradients of light absorbing carbon over northern Europe

2008

In situ measurements have been made in the upper troposphere of the properties of particles containing light absorbing carbon (LAC). These measurements, made in late November 2006 over northern Europe, show that the average LAC mass concentration varies between 1 and 5 ng m−3 over a latitude range 50° to 70°N, with maxima at 50° and 66°. The relative fraction of all particles larger than 0.1 µm that contain LAC decreases at higher latitudes. The derived extinction coefficient, which also increases with latitude, reaches a maximum of 1.4 Mm−1 at 66°. The air mass histories associated with the LAC were evaluated with back trajectory analysis using wind field analysis from the European Center …

Sensing properties of ZnO nanostructured layers

2017

Nanostructured ZnO layers have been deposited onto SiO 2 /Si substrates by spray pyrolysis, with previously patterned interdigitated gold electrodes. We have then measured the capacitive and resistive response against ambient parameters such as relative humidity and illumination.

Greenhouse climate control using wireless sensors

2008

A wireless sensor network for vineyard management in Sicily (Italy)

2013

Wine quality depends on many factors, such as the choice of variety, stock, training system, pruning as well as environmental parameters and cultivation techniques performed in the vineyard. Monitoring the micro-climate of grapevine allows to conveniently perform the most important cultivation techniques (soil management, pesticide treatments, green pruning, harvest) thus reducing the operating costs of the vineyard, and increasing the overall quality of the grapes. The aim of the present study is to monitor the micro-climate of grapevine in order to control spring period hazards, to reduce the operating costs of the vineyard and to increase the quality of grapes. For this purpose a Wireles…

Contenimento naturale di Bactrocera oleae (Rossi): clima o parassitoidi? Confronto tra Western Cape (Sud Africa) e Sicilia

2017

Bactrocera oleae (Rossi), mosca delle olive, è presente anche in Sud Africa, ma finora non si sono avute notizie di infestazioni economicamente rilevanti negli oliveti. L’accertata presenza di un maggior numero di braconidi parassitoidi della mosca delle olive rispetto alle aree mediterranee è stata ed è considerata da molti autori la principale causa di queste minori infestazioni, senza che però siano stati eseguiti in Sud Africa adeguati studi sulle infestazioni da B. oleae e sui fattori cli- matici delle aree interessate. Analizzando recenti dati sui livelli d’infestazione di B. oleae registrati su olivo coltivato e selvatico nel Western Cape e in Sicilia, appaiono simili in una norm…

Effects of temperature and desiccation on ex situ conservation of nongreen fern spores

2012

Premise of the study Fern spores are unicellular and haploid, making them a potential model system to study factors that regulate lifespan and mechanisms of aging. Aging rates of nongreen spores were measured to compare longevity characteristics among diverse fern species and test for orthodox response to storage temperature and moisture. Methods Aging of spores from 10 fern species was quantified by changes in germination and growth parameters. Storage temperature ranged from ambient room to -196°C (liquid nitrogen); spores were dried to ambient relative humidity (RH) or using silica gel. Key results Survival of spores varied under ambient storage conditions, with one species dying within …

Water properties in fern spores: sorption characteristics relating to water affinity, glassy states, and storage stability.

2007

Ex situ conservation of ferns may be accomplished by maintaining the viability of stored spores for many years. Storage conditions that maximize spore longevity can be inferred from an understanding of the behaviour of water within fern spores. Water sorption properties were measured in spores of five homosporeous species of ferns and compared with properties of pollen, seeds, and fern leaf tissue. Isotherms were constructed at 5, 25, and 45 degrees C and analysed using different physicochemical models in order to quantify chemical affinity and heat (enthalpy) of sorption of water in fern spores. Fern spores hydrate slowly but dry rapidly at ambient relative humidity. Low Brunauer-Emmet-Tel…

A Comparative Study of Soil Suction Measurement Using Two Different High-Range Psychrometers

2007

An extensive experimental study was performed to compare the measurement capabilities within different ranges of two total suction measurement equipment: SMI transistor psychrometers and a chilled-mirror dew-point psychrometer (WP4 Dewpoint PotentiaMeter). The equipment were used in a systematic way to determine the relative humidity of the environment surrounding different compacted clayey soils along drying paths and covering a wide total suction range (0.1 to 70 MPa). The equipment description and the calibration protocols followed are presented, as well as suggestions regarding the improvement of their performance. The water retention curves of two different compacted clayey soils are p…