Search results for "control."
showing 10 items of 13063 documents
Hydrodynamic characterization of a new small-scale reactor mixed by a magnetic bar
2015
International audience; The purpose of this study was to evaluate the mixing characteristics of a new milliliter-scale (mL-scale) reactor developed for studying enzymatic activity or physiological cell response. The mL-scale reactor was designed to enable the integration of several sensors to carry out dynamic measurements in a controlled environment. Rapid homogeneity of the entire system is essential to ensure reproducible and reliable results, consequently the reactor was stirred to optimize both mass and heat transfers. A comparative study using three different techniques was undertaken to study mixing performances in the system. Firstly, mixing time (4,) was estimated in the reactor us…
Aeration control in membrane bioreactor for sustainable environmental footprint
2020
In this study different scenarios were scrutinized to minimize the energy consumption of a membrane bioreactor system for wastewater treatment. Open-loop and closed-loop scenarios were investigated by two-step cascade control strategies based on dissolved oxygen, ammonia and nitrite concentrations. An integrated MBR model which includes also the greenhouse gas formation/emission processes was applied. A substantial energy consumption reduction was obtained for the closed-loop scenarios (32% for Scenario 1 and 82% for Scenario 2). The air flow control based on both ammonia and nitrite concentrations within the aerobic reactor (Scenario 2) provided excellent results in terms of reduction of o…
Bacillus subtilis BS-2 and Peppermint Oil as Biocontrol Agents Against Botrytis cinerea
2019
Abstract The purpose of this study was to assess the activity of Bacillus subtilis BS-2 and peppermint oil against Botrytis cinerea. In this study parameters such as the age and the density of the bacterial culture and the incubation temperature were taken into consideration. Furthermore, the cellulolytic activity of the bacterium was determined. The effect of peppermint oil was evaluated at a concentration range of 0.5-4.0 %. The research was conducted with a dual culture plate method. The influence of B. subtilis BS-2 and peppermint oil on the growth of B. cinerea was evaluated based on the growth rate index. It was noted that the bacterial culture occurred at an initial density of OD 560…
Use of Plant Water Extracts for Weed Control in Durum Wheat (Triticum turgidum L. Subsp. durum Desf.)
2020
The use of plant water extracts to control weeds is gaining attention in environmentally-friendly agriculture, but the study of the effect that such extracts may exert on the yield of durum wheat is still unexplored. In 2014 and 2016, the herbicidal potential of several plant water extracts was field tested on durum wheat (cv Valbelice). In 2014, extracts obtained from Artemisia arborescens, Rhus coriaria, Lantana camara, Thymus vulgaris, and Euphorbia characias were used, whereas in 2016 only A. arborescens and R. coriaria were tested as &ldquo
Use of solid state fermentation to produce Beauveria bassiana for the biological control of european corn borer
1993
The production process of a new bioinsecticide against european corn borer is described. The entomopathogenic fungus, Beauveria bassiana, is cultivated by Solid State Fermentation (SSF). The culture support chosen, clay microgranules, humidified with optimal nutritive solution, is incubated in optimal conditions during 48 hours, then dried for 5 days. The bioinsecticide can be directly used after harvesting, without formulation. This process is original for several reasons : - The granulometry (500 microm) and the bulk density (0.6) of the microgranules are compatible with the mechanical standard application of pesticides on corn. - The bioinsecticide could be produced in a pilot reactor of…
Mycelial development of Fusarium oxysporum in the vicinity of tomato roots
1999
The patterns of mycelial development (length and branching) of five strains of Fusarium oxysporum were measured in the vicinity of tomato and wheat roots. Two strains were of f. sp. lycopersici, two of f. sp. radicis-lycopersici and the fifth was a non-pathogenic strain currently used as a biocontrol agent. Hyphal extension and branching were measured microscopically using a CCD camera and an image analyser. Furthermore, the role of soluble root exudates, insoluble root materials, glucose supply, and nitrogen supply (casamino acids) on mycelial development was investigated. Each strain had its own pattern of development in the absence of a root. Fungal development of all five strains was st…
Warmer temperatures reduce the influence of an important keystone predator
2017
Predator–prey interactions may be strongly influenced by temperature variations in marine ecosystems. Consequently, climate change may alter the importance of predators with repercussions for ecosystem functioning and structure. In North-eastern Pacific kelp forests, the starfish Pycnopodia helianthoides is known to be an important predator of the purple sea urchin Strongylocentrotus purpuratus. Here we investigated the influence of water temperature on this predator–prey interaction by: (i) assessing the spatial distribution and temporal dynamics of both species across a temperature gradient in the northern Channel Islands, California, and (ii) investigating how the feeding rate of P. heli…
Use of sewage sludge compost and Trichoderma asperellum isolates to supress Fusarium wilt of tomato
2002
It has been reported that plant growth media amended with composted bark suppress Fusarium wilts whereas media amended with composted municipal sludge aggravate this disease. However, in this study, a compost prepared from vegetable and animal market wastes, sewage sludge and yard wastes showed a high ability to suppress Fusarium wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici race 1. The ability of this compost to suppress Fusarium wilt of tomato was compared with that of a peat mix (peat:vermiculite, 1:1 v/v) and a naturally suppressive soil from Chateaurenard, France. The compost and the soil from Chateaurenard were highly suppressive, whereas the peat mix was highly condu…
Shifts in the structure of rhizosphere bacterial communities of avocado after Fusarium dieback
2021
The rhizosphere microbiome is critical for plant growth and protection against plant pathogens. However, rhizosphere microbial communities are likely to be restructured upon plant infection by fungal pathogens. Our objective was to determine the shifts in rhizosphere bacterial communities of avocado trees (Persea americana Mill.) after Fusarium dieback (FD), a disease triggered by the symbiotic fungi of invasive ambrosia beetles (Euwallacea kuroshio and Euwallacea sp. nr. fornicatus), using 16S rDNA gene amplicon sequencing and a culture-dependent approach. Rhizosphere soil samples were collected from five asymptomatic and five FD-symptomatic avocado trees in a Californian orchard. Sequence…
Isolation and characterization of nonpathogenic Fusarium oxysporum isolates from the rhizosphere of healthy banana plants
2006
Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; One of the most serious diseases of banana is fusarium wilt, caused by Fusarium oxysporum f.sp. cubense (Foc). The objectives of this study were to isolate and identify nonpathogenic F. oxysporum strains from soils suppressive to banana wilt, and to determine the diversity of these isolates. More than 100 Fusarium strains were isolated from the rhizosphere of banana plants and identified to species level. Pathogenicity testing was carried out to confirm that these isolates were nonp…