Search results for "55"
showing 10 items of 2320 documents
Aerosol- and updraft-limited regimes of cloud droplet formation: Influence of particle number, size and hygroscopicity on the activation of cloud con…
2009
We have investigated the formation of cloud droplets under pyro-convective conditions using a cloud parcel model with detailed spectral microphysics and with the κ-Köhler model approach for efficient and realistic description of the cloud condensation nucleus (CCN) activity of aerosol particles. Assuming a typical biomass burning aerosol size distribution (accumulation mode centred at 120 nm), we have calculated initial cloud droplet number concentrations (<i>N<sub>CD</sub></i>) for a wide range of updraft velocities (<i>w</i>=0.25–20 m s<sup>&minus;1</sup>) and aerosol particle number concentrations (<i>N<sub>CN</sub><…
Suppression of new particle formation from monoterpene oxidation by NOx
2014
The impact of nitrogen oxides (NOx = NO + NO2) on new particle formation (NPF) and on photochemical ozone production from real plant volatile organic compound (BVOC) emissions was studied in a laboratory setup. At high NOx conditions ([BVOC] / [NOx] x] > 23 ppb) new particle formation was suppressed. Instead, photochemical ozone formation was observed resulting in higher hydroxyl radical (OH) and lower nitrogen monoxide (NO) concentrations. When [NO] was reduced back to levels below 1 ppb by OH reactions, NPF was observed. Adding high amounts of NOx caused NPF to be slowed by orders of magnitude compared to analogous experiments at low NOx conditions ([NOx] ~300 ppt), although OH concentrat…
Effect of abrasive pretreatment on hot dried goji berry
2015
Goji (Lycium barbarum L.) is a Solanaceous deciduous shrub that grows in China, Tibet and other parts of Asia. Nowadays, goji berries are known as being very rich in nutrients with high antioxidant capacity, fact for which they were included in the novel category of “superfruits”. Goji berries contain high amounts of antioxidants, carotenoids, vitamin A and zeaxanthin. Most of goji berries produced are dried because they are very delicate fruits. Drying process improves fruit stability, since it decreases considerably the water activity of the food, reduces microbiological and enzymatic activity and minimizes physical and chemical reactions during storage. However, drying of goji berries ca…
Acceleration Assessment During Mechanical Harvest of Grapes Using a non Commercial Instrumented Sphere
2017
The use of the harvesting machine for grape wine has the limit of the production of must coming out from the detachment of the berries that could reflect negatively on the quality of the final product. It depends on many factors including grapes variety, ripeness and frequency of the harvesting machine shakers. The shaking frequency generally adopted is the one that achieves the maximum harvest efficiency, that means high work capacity and low grape juice production. In this paper, the authors present a new system to measure the accelerations received by grapevine during mechanical harvest with the aim of evaluating the influence of the shaking frequency on the quality of the must obtained.…
The Italian Consumers’ Preferences for Pasta: does Environment Matter?
2017
Demand for food in developed countries is nowadays moving towards increasing contents of quality requisites. A large part of consumers lives in cities and demand for tasty and healthy food but pays also attention to environmental concerns and cultural references, to express their own lifestyles and ethical values. Agriculture can therefore increase income and employment through the supply of a wide range of valuable goods and services related with the countryside and the environment. As an effect of climate and environmental conditions, pasta made by Sicilian durum wheat, can be considered safer and healthier than standard pasta (alias common pasta) manufactured by major producing companies…
Influence of O2 on extra virgin olive oil fatty acids composition during malaxation
2017
Many variables are related to extra virgin olive oil (EVOO) quality and, therefore, to its polyphenols content and fatty acids composition including the steps that lead to EVOO extraction, considering that it is mainly contained in the vacuoles of the fruit mesocarp. The main steps of EVOO production are: harvest, crushing, malaxation, centrifugation, storage and filtration. Considering the olive oil extraction procedures, many studies have been conducted in recent years on oil mill plant and processes for improving EVOO quality. Malaxer is the most studied machine among all; it is responsible for malaxation, which represents a very important and critical step in the EVOO extraction process…
AREA-TO-VOLUME DATA TRANSLATION IN THE MEASUREMENT OF BUBBLE SIZE DISTRIBUTIONS VIA LASER SHEET AND IMAGE ANALYSIS
2009
Not available.
kLa MEASUREMENT IN BIOREACTORS
2010
For accurately measuring kLa in bioreactors the dynamic pressure method (DPM) was introduced by Linek et al. (1993). In this work a simplified version of the same method is discussed. With respect to the original DPM, the simplified version greatly simplifies data treatment. In fact final constant slope observable in the usual semi-log diagram of residual driving force versus time may be simply corrected to obtain the real kLa value with negligible inaccuracy. Experimental data obtained on a lab-size stirred tank reactor confirm all model predictions, including the feature that the adoption of large pressure changes may lead to a better accuracy.
A pH Study for the Degradation of Acetaminophen with Iron Oxide Nanostructures
2019
[EN] Nowadays, there is an increasing interest in the degradation of organic compounds in wastewater, since they are detrimental for the water quality. Different metal oxides have been studied as photocatalysts in the photoelectrocatalytic degradation of pharmaceutical products using UV light. Iron oxide nanostructures are a promising option in this field since their band gap (~ 2.1 eV, corresponding to ~590 nm) can absorb visible light, which in turn allows the degradation by using sunlight. Iron oxide nanostructures are known to be stable in alkaline solutions, but some organic compounds can vary their structure with pH. Then, a pH study is needed in order to stablish the optimum value to…
Green Synthesis of Vanillin: Pervaporation and Dialysis for Process Intensification in a Membrane Reactor.
2019
In the present work, two different membrane processes (pervaporation and dialysis) are compared in view of their utilization in a membrane reactor, where vanillin, which is probably the most important aroma of the food industry, is synthesized in a green and sustainable way. The utilized precursor (ferulic acid, which is possibly a natural product from agricultural wastes) is partially oxidized (photocatalytically or biologically) and the product is continuously recovered from the reacting solution by the membrane process to avoid its degradation. It is observed that pervaporation is much more selective towards vanillin than dialysis, but the permeate flux of dialysis is much higher. Furthe…