Search results for "complex mixtures"

A numerical model of the cloud-topped planetary boundary-layer: radiative forcing of aerosols in stratiform clouds

1998

In a numerical sensitivity study with the microphysical stratus model MISTRA the impact of aerosol particles on the time evolution of stratiform clouds is investigated. Four model runs with different aerosol size distributions are presented. Two size distributions are typical for maritime and continental air masses. The third model run consists of a mixture of maritime and rural aerosol particles, while in the fourth case study rural aerosol particles with a reduced water solubility are utilized. The numerical results show that the microphysical structure of the clouds is strongly affected by the physico-chemical properties of the aerosol particles. In the maritime case, with a relatively l…

Effect of kind and content of organo-modified clay on properties of PET nanocomposites

2011

In this work we report the properties of nanocomposite based on PET with two different samples of organically modified montmorillonites. In particular, we studied the effect of the filler concentration on morphology, rheology, and mechanical performance, focusing our attention on the effect of the degradation phenomena of the clay modifiers. The results indicate that at low clay level the morphology achieved is mainly intercalated. On increasing the filler level, coalescence and/or bad defragmentation phenomena induce a coarser morphology, as confirmed by XRD, SEM, and TEM observations. When a more polar organic modifier is used to modify the clay, the particle adhesion and distribution is …

The impact of organic amendments on soil hydrology, structure and microbial respiration in semiarid lands

2016

Abstract Few studies have considered the effect of organic amendments on soil microbial activity and its contributions to hydraulic conductivity under field conditions in semiarid region soils with different textures and degrees of aggregate stability. This study was performed to investigate the relationship between selected soil properties and hydraulic conductivity in response to different types and application rates of organic amendments. For this purpose, urban municipal solid waste (MSW) compost and alfalfa residue (AR) were applied at different rates of 0 (control), 10 Mg ha− 1 and 30 Mg ha− 1 to clay loam and loamy sand soils under field conditions. Results show that after two years,…

M6_Microfluidics_for_CNT

2018

The hydrodynamic trap holds an incoming droplet until the arrival of following droplet. The previous droplet leaves the trap in very rapid manner.

Soil remediation: humic acids as natural surfactants in the washings of highly contaminated soils

2005

The remediation of the highly contaminated site around the former chemical plant of ACNA (near Savona) in Northern Italy is a top priority in Italy. The aim of the present work was to contribute in finding innovative and environmental-friendly technology to remediate soils from the ACNA contaminated site. Two soils sampled from the ACNA site (A and B), differing in texture and amount and type of organic contaminants, were subjected to soil washings by comparing the removal efficiency of water, two synthetic surfactants, sodium dodecylsulphate (SDS) and Triton X-100 (TX100), and a solution of a natural surfactant, a humic acid (HA) at its critical micelle concentration (CMC). The extraction …

Alkali consumption of aliphatic carboxylic acids during alkaline pulping of wood and nonwood feedstocks

2013

Abstract The carbohydrate degradation products have been examined, which are formed during the conventional kraft pulping of a softwood, hardwoods, bamboo, and wheat straw as well as soda and soda-anthraquinone pulping of wheat straw. The focus was on “volatile” acids such as formic and acetic acids and “nonvolatile” hydroxy monocarboxylic and dicarboxylic acids. The different consumption profiles were obtained for the charged alkali required for the neutralization of these aliphatic acids depending on the feedstock and the cooking method. The relative composition of the acid fraction in the black liquors of softwood and hardwood and nonwood feedstocks showed characteristic variations. Howe…

Variación espacial de la exposición a contaminación atmosférica en la ciudad de Valencia y su relación con un índice de privación

2013

Objetivo: Evaluar la variación espacial de la exposición a dióxido de nitrógeno (NO2) en la ciudad de Valencia y su relación con la privación socioeconómica y la edad. Métodos: La población por sección censal (SC) procede del Instituto Nacional de Estadística. Los niveles de NO2 se midieron en 100 puntos del área de estudio, mediante captadores pasivos, en tres campañas entre 2002 y 2004. Se utilizó regresión por usos del suelo (LUR) para obtener el mapa de los niveles de NO2. Las predicciones del LUR se compararon con las proporcionadas por: a) el captador más cercano de la red de vigilancia, b) el captador pasivo más cercano, c) el conjunto de captadores en un entorno y d) kriging. Se asi…

2017

Abstract. We present a sensitivity study on transatlantic dust transport, a process which has many implications for the atmosphere, the ocean and the climate. We investigate the impact of key processes that control the dust outflow, i.e., the emission flux, convection schemes and the chemical aging of mineral dust, by using the EMAC model following Abdelkader et al. (2015). To characterize the dust outflow over the Atlantic Ocean, we distinguish two geographic zones: (i) dust interactions within the Intertropical Convergence Zone (ITCZ), or the dust–ITCZ interaction zone (DIZ), and (ii) the adjacent dust transport over the Atlantic Ocean (DTA) zone. In the latter zone, the dust loading show…

The influence of absorbed solar radiation by Saharan dust on hurricane genesis

2015

To date, the radiative impact of dust and the Sahar an air layer (SAL) on North Atlantic hurricane activity is not yet known. According to previous studies, dust stabilizes the atmosphere due to absorption of solar radiation but thus shifts convection to regions more conducive for hurricane genesis. Here we analyze differences in hurricane genesis and frequency from ensemble sensitivity simulations with radiatively active and inactive dust in the aerosol-climate model ECHAM6-HAM. We investigate dust burden and other hurricane-related variables and determine their influence on disturbances which develop into hurricanes (developing disturbances, DDs) and those which do not (nondeveloping dist…

Responses of microbial activity and decomposer organisms to contamination in microcosms containing coniferous forest soil.

2002

Soil respiration from microcosms contaminated with pentachlorophenol, 2-ethanolhexanoate, creosote, CuSO4, and benomyl was measured in order to evaluate usefulness of soil microcosms and microbial respiration rate monitoring as a toxicity test in soils with high organic matter content. Coniferous forest soil and its organisms were used as test objects. In addition, how a short-term low temperature period including frost affects respiration dynamics in stressed soils was studied, i.e., whether contaminants reduce resistance of the community to other (also natural) stresses. In addition, at the end of the experiment, effects of contaminants on faunal and microbial community structures were an…