Influence of temperature on microbial colonisation of clayey schist as a support media of a submerged filter for groundwater denitrification

2007 ◽  
Vol 55 (8-9) ◽  
pp. 165-172 ◽  
Author(s):  
A. De la Rúa ◽  
B. Rodelas ◽  
J. González-López ◽  
M.A. Gómez
Keyword(s):  
Biofilm Formation ◽  
Effect Of Temperature ◽  
Cold Environments ◽  
Pseudomonas Mandelii ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Denitrification Activity ◽  
Natural Microbiota ◽  
Denitrification Process ◽  
Made In

The effect of temperature on biofilm formation and denitrification activity was evaluated. Assays were made in a lab-scale submerged filter for the denitrification of polluted groundwater, with and without a previous inoculation. The inoculation was carried out with a selected strain of Pseudomonas mandelii. Different temperatures were tested: 5, 10, 20 and 30 °C. Biofilm observations were made, and monitoring of the denitrification capacity of the system was maintained during the experiment. Our results showed that both colonisation of the support material of the filter and biofilm maturity have a dependency with temperature, with an optimum temperature of 20 °C if the system was previously inoculated with the Pseudomonas mandelii strain. For a correct achievement of the denitrification process, a previous inoculation of the system is essential. Although the development of a biofilm from the natural microbiota present in the groundwater is possible, it is not capable to adequately denitrify polluted groundwater. In terms of the correct achievement of the denitrification process, temperature affects the operation of the system at cold environments, although the use of Pseudomonas mandelii strain A103 allows denitrification at 10–30 °C with very good results (above 90% removal), affecting only to the time needed for the stabilisation of the system.

scholarly journals Production of lipids from psychrophilic microalgae present in antarctic glaciers for the synthesis of biofuel

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Geovanny Huilca ◽  
L Licto ◽  
Ronny Flores
Keyword(s):  
Sensory Quality ◽  
Negative Impact ◽  
Chemistry Laboratory ◽  
Sustainable Chemistry ◽  
Lipid Concentration ◽  
Cold Environments ◽  
Chlorella Sp ◽  
A Value ◽  
Different Temperatures ◽  
Made In

Microalgae had a negative impact on the overall sensory quality. Psychrophilic microalgae live in extremely cold environments, their growth increases because they have enzymes in their structure that only adapt to temperatures below 0 ° C. For this reason, the Sustainable Chemistry Laboratory of the Central University of Ecuador, together with the Ecuadorian Antarctic Institute (INAE), made an expedition in the Greenwich, Roberts, Dee, Barrientos and Antarctic Towers where several microalgae consortia were collected, where 15 samples from Greenwich Island and Roberts were analyzed at 21 days at different temperatures, from which the genera Chlorella sp, Chlorococcum sp and Stichococcus sp. Subsequently, isolation was made in Petri dishes to obtain monoalgal cultures. Each of the isolated genera was massified in a volume of 5 mL until reaching a volume of 250 mL in modified M1 medium at a temperature of 4 ° C and 24 ° C, 5000 lux and a photoperiod of 12:12 hours. The Bligh & Dyer method was used for the extraction of lipids. The values of the lipid concentration showed that the genus Chlorella sp is the highest concentration with a value of 0.2802 mg / mL at 4 ° C and a value of 2.6704 mg / mL at 24 ° C on the 22nd day of its exponential phase in comparison with the genera Chlorococcum and Stichococcus sp.

The Influence of Temperature on the Galvanic Corrosion in Multi-Material System in Seawater

2015 ◽  
Vol 1101 ◽  
pp. 225-228
Author(s):  
Chun Li Wang ◽  
Jian Hua Wu
Keyword(s):  
Corrosion Behavior ◽  
Galvanic Corrosion ◽  
Effect Of Temperature ◽  
Material System ◽  
Ni Alloy ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Zero Resistance ◽  
Increasing Temperature ◽  
Surface Morphologies

The galvanic corrosion behavior of titanium (TA2)/Cu-Ni alloy (B10)/low alloy steel (921A) multi-material system has been studied using a zero-resistance ammeter (ZRA) in seawater at different temperatures. After the tests, the surface morphologies of the samples were detected by SEM. Results showed galvanic corrosion behavior of TA2/B10/921A fulfill the mixed potential theory, 921A acts as the anode and both TA2 and B10 act as the cathodes. The effect of temperature on the galvanic corrosion is important, the corrosion rate increases with increasing temperature.

scholarly journals Effect of temperature on capping efficiency of zeolite and activated carbon under fabric mats for interrupting nutrient release from sediments

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Seung-Hee Hong ◽  
Jae-In Lee ◽  
Chang-Gu Lee ◽  
Seong-Jik Park
Keyword(s):  
Activated Carbon ◽  
Nutrient Release ◽  
Nonwoven Fabric ◽  
Effect Of Temperature ◽  
Overlying Water ◽  
P Release ◽  
Incubation Experiments ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Do Concentration

Abstract We investigated the influence of temperature on the capping efficiency to interrupt the release of nutrients from lake sediments. A 3-cm layer of Zeolite (ZL) or activated carbon (AC) was placed on the contaminated sediments, and nonwoven fabric mats (NWFM) were placed on top of these capping materials. Laboratory incubation experiments were performed under three different temperatures, namely 4, 15, and 30 °C. Under the uncapped condition at 30 °C, dissolved oxygen (DO) was depleted after 30 days, while at 4 °C and 15 °C, DO was present until the end of this experiment. DO concentration in overlying water was more dependent on the temperature than capping condition. ZL/NWFM effectively blocked the release of N from the sediments, and the capping efficiencies of ZL/NWFM for NH4-N at 4, 15, and 30 °C were 98%, 96%, and 94%, respectively. For the interruption of P release, both ZL/NWFM and AC/NWFM were not effective at 4 and 15 °C. At 30 °C, however, AC/NWFM was effective, and its capping efficiencies at 30 °C for PO4-P and T-P were 74.0% and 79.9%, respectively. In summary, nutrient release from sediments was accelerated at higher temperatures, and the effect of capping was significant at high temperature.

Crystallization and the Relaxation of Stress in Stretched Unvulcanized Natural Rubber

1956 ◽  
Vol 29 (4) ◽  
pp. 1195-1198
Author(s):  
A. V. Tobolsky ◽  
G. M. Brown
Keyword(s):  
Natural Rubber ◽  
Temperature Region ◽  
Effect Of Temperature ◽  
Careful Study ◽  
Rubber Vulcanizate ◽  
Crystallization Region ◽  
Different Temperatures ◽  
Made In

Abstract The first observation made in this laboratory in 1946 on the effect of crystallization on stress decay at constant extension was made on a vulcanized Neoprene GN gum stock. It was found that this rubber showed only slight stress decay after 100 hours at 35° C and 50 per cent extension. However, a complete decay of stress to zero stress was observed after only 50 hours at 0° C and 50 per cent extension. Furthermore, the sample after reaching zero stress began to increase in length (spontaneous elongation). This phenomenon was attributed to crystallization. Observations of spontaneous elongation, but no stress decay measurements, were previously reported for vulcanized and unvulcanized natural rubber and for vulcanized and unvulcanized ether polysulfide rubber. It was decided to make a careful study of the effect of temperature and elongation on the stress-decay curves of unvulcanized rubber (cast latex sheet) in the temperature region of crystallization. Some time after these studies were completed, two papers have appeared in which stress decay to zero stress in rubber vulcanizates due to crystallization were reported. In one of these a rather thorough study was made of the decay of stress and change in volume of a natural rubber vulcanizate at −26° C and maintained at four different extension ratios. Our own work on unvulcanized natural rubber was carried out at seven different temperatures in the crystallization region, and were made at five different extension ratios. Quite surprisingly, four of these are the same as were used by Gent. There are interesting differences as well as similarities between our work and the results reported for vulcanized natural rubber.

Phenotypic plasticity of pigmentation and morphometric traits inPnigalio soemius(Hymenoptera: Eulophidae)

2007 ◽  
Vol 97 (1) ◽  
pp. 101-109 ◽  
Author(s):  
U. Bernardo ◽  
P.A. Pedata ◽  
G. Viggiani
Keyword(s):  
Morphological Traits ◽  
Phenotypic Variability ◽  
Economic Importance ◽  
Effect Of Temperature ◽  
Morphometric Traits ◽  
Influence Of Temperature ◽  
Natural Hosts ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Range Of Variation

AbstractSpecies of the genusPnigalioSchrank are ectoparasitoids on several pest insects. Most species are polyphagous parasitoids of lepidopteran and dipteran leafminers. Despite their potential economic importance, information on intraspecific phenotypic variability is insufficient.Pnigalio soemius(Walker) was reared at five different temperatures (10, 15, 20, 25, 30°C) on mature larvae of one of its natural hosts,Cosmopterix pulchrimellaChambers (Lepidoptera: Cosmopterigidae), to investigate the influence of temperature on size, colour and other morphological traits, and to measure the range of variation of several characters. Thermal developmental reaction norms, which represent the effect of temperature during growth and development on the value of some adult traits, were produced. The results confirmed the influence of temperature on numerous characters and that these characters had a larger range of variation than realized previously in the construction of taxonomic keys to species. In particular, the number and position of the costulae on the propodeum and colour of the gaster were affected by rearing temperature.

scholarly journals Effect of Temperature on Life History of Bemisia Tabaci (Gennadius) (Homoptera: Aleyrodidae) on Cassava Manihot Esculenta Crantz

2021 ◽  
Vol 4 (1) ◽  
pp. 912-920
Author(s):  
Nguyen Duc Khanh ◽  
Le Ngoc Anh ◽  
Ho Thi Thu Giang
Keyword(s):  
Life History ◽  
Bemisia Tabaci ◽  
Effect Of Temperature ◽  
Degree Days ◽  
Manihot Esculenta Crantz ◽  
Developmental Threshold ◽  
Wide Range ◽  
Important Pest ◽  
Different Temperatures ◽  
Influence Of Temperature On

The aim of the present study was to evaluate the relationships between environmental temperatures and life-history traits of whitefly Bemisia tabaci on cassava in the Northern part of Vietnam. The influence of temperature on the biological characteristics of whitefly B. tabaci fed on cassava was evaluated at 20ºC, 25ºC, 27.5ºC, and 30ºC using individual insect rearing methodology. Results of the study showed that the development time from egg to adult of B. tabaci was influenced by temperatures. The data indicated that under different temperatures (20ºC, 25ºC, 27.5ºC, and 30ºC), the life cycle of B. tabaci were 41.46, 28.64, 24.29, and 20.25 days, respectively. The determination of lower developmental threshold and degree days for whitefly development were 11.2ºC and 344.8 degree-days. There were 14.31 whitefly generations within 1 year on cassava suggesting this plant is a suitable host plant for the development and reproduction of B. tabaci. Female longevity ranged from 4.92 to 10.23 days. The fecundity ranged from 49.3 to 74.0 eggs/female. The mortality rate reached its highest rate of 36.27% at 30ºC. Our results suggested that B. tabaci had high reproduction rates and demonstrated their positive fitness traits on cassava in a wide range of temperatures, being a potential important pest of cassava cultivars.

scholarly journals The effect of temperature on pollen germination and pollen tube growth of sour cherry cultivars

2014 ◽  
Vol 59 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Dragan Milatovic ◽  
Dragan Nikolic
Keyword(s):  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Pollen Germination ◽  
Pollen Grains ◽  
Sour Cherry ◽  
Tube Growth ◽  
Effect Of Temperature ◽  
Different Temperatures ◽  
Influence Of Temperature On

The study was carried out to determine the effect of three different temperatures (5, 15 and 25?C) on in vitro pollen germination and pollen tube growth of five sour cherry cultivars: ?Heimanns Konservenweichsel?, ?Kelleriis 14?, ?Oblacinska?, ?Rexelle? and ?Sumadinka?. Pollen germination a % agar % Temperature significantly affected pollen germination. High germination rates (50-70%) were obtained at both 15?C and 25?C. Satisfactory germination rates (42-51%) were also obtained at 5?C in some cultivars (?Rexelle?, ?Sumadinka? and ?Heimanns Konservenweichsel?). The influence of temperature on the pollen tube growth was more prominent. The length of pollen tubes was three to six times higher at 15?C and 25?C in comparison with 5?C. This has led to the conclusion that the temperature of 5?C, although it could be adequate for pollen germination, is not high enough for optimal pollen tube growth. was determined by germinating pollen grains in culture medium containing 0.7agar-and 15sucrose.

scholarly journals Influence of temperature on tungsten carbide formation in a beam plasma discharge

2021 ◽  
Vol 2064 (1) ◽  
pp. 012055
Author(s):  
G K Zhanbolatova ◽  
V V Baklanov ◽  
M K Skakov ◽  
I A Sokolov ◽  
O S Bukina ◽  
...  
Keyword(s):  
Carbon Film ◽  
Sample Surface ◽  
Irradiation Temperature ◽  
Effect Of Temperature ◽  
Carbide Formation ◽  
Tungsten Carbides ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Tungsten Surface ◽  
Tungsten Monocarbide

Abstract This paper presents a method of tungsten surface carbidization using a plasma-beam setup to assess the effect of temperature on the formation of tungsten carbides. Methane was used as a plasma-forming gas. The working gas pressure in the chamber was (1.3–1.4)10−1 Pa. Experiments on the formation of carbides were carried out at different temperatures (700-1000°C). It was recorded that at a temperature of 700°C, crystallization centers of a carbon film appear on the sample surface. With an increase in the irradiation temperature to 800°C and 900°C, the surface of the samples is covered with a continuous carbon film. As a result of the experimental work carried out, it was found that the formation of tungsten semicarbide occurs at 900°C. A further increase in temperature leads to the formation of tungsten monocarbide.

scholarly journals Temperature Dependency of Wing-Beat Frequency in Intact and Deafferented Locusts

1992 ◽  
Vol 162 (1) ◽  
pp. 295-312
Author(s):  
JANE A. FOSTER ◽  
R. MELDRUM ROBERTSON
Keyword(s):  
Ambient Temperature ◽  
Locusta Migratoria ◽  
Beat Frequency ◽  
Effect Of Temperature ◽  
Wing Beat ◽  
Neural Basis ◽  
Wing Beat Frequency ◽  
Thoracic Temperature ◽  
Different Temperatures ◽  
Made In

Locusts do not regulate thoracic temperature during flight and as a result the thoracic temperature of a flying locust generally exceeds ambient temperature by 5–8 °C. Elevated thoracic temperatures were shown to affect wing-beat frequency in intact and deafferented Locusta migratoria. Tethered locusts were flown in a wind tunnel. Temperature was elevated by increasing the ambient temperature of the apparatus and by exposing flying animals to heat pulses. Electromyographic (EMG) recordings were made in deafferented locusts perfused with salines at different temperatures. Wing-beat frequency was shown to vary with thoracic temperature in both the intact and the deafferented situation. The slope of the rise in wing-beat frequency with experimental increases in thoracic temperature was similar in intact and deafferented animals. These experiments demonstrate an effect of temperature on the central flight circuitry. Further intracellular investigationsare needed to determine the neural basis of these effects.

scholarly journals Effect of Nitrate and Acetylene on nirS, cnorB, and nosZ Expression and Denitrification Activity in Pseudomonas mandelii

2009 ◽  
Vol 75 (15) ◽  
pp. 5082-5087 ◽  
Author(s):  
Saleema Saleh-Lakha ◽  
Kelly E. Shannon ◽  
Sherri L. Henderson ◽  
Bernie J. Zebarth ◽  
David L. Burton ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gas Chromatography ◽  
Electron Acceptor ◽  
Pseudomonas Mandelii ◽  
Denitrification Gene ◽  
Reverse Transcription Quantitative Pcr ◽  
Denitrification Activity ◽  
Acetylene Blockage ◽  
Denitrification Genes ◽  
Denitrification Process

ABSTRACT Nitrate acts as an electron acceptor in the denitrification process. The effect of nitrate in the range of 0 to 1,000 mg/liter on Pseudomonas mandelii nirS, cnorB, and nosZ gene expression was studied, using quantitative reverse transcription-quantitative PCR. Denitrification activity was measured by using the acetylene blockage method and gas chromatography. The effect of acetylene on gene expression was assessed by comparing denitrification gene expression in P. mandelii culture grown in the presence or absence of acetylene. The higher the amount of NO3 − present, the greater the induction and the longer the denitrification genes remained expressed. nirS gene expression reached a maximum at 2, 4, 4, and 6 h in cultures grown in the presence of 0, 10, 100, and 1,000 mg of KNO3/liter, respectively, while induction of nirS gene ranged from 12- to 225-fold compared to time zero. cnorB gene expression also followed a similar trend. nosZ gene expression did not respond to NO3 − treatment under the conditions tested. Acetylene decreased nosZ gene expression but did not affect nirS or cnorB gene expression. These results showed that nirS and cnorB responded to nitrate concentrations; however, significant denitrification activity was only observed in culture with 1,000 mg of KNO3/liter, indicating that there was no relationship between gene expression and denitrification activity under the conditions tested.

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