Simultaneous Effect Of Temperature Research Articles

Pengaruh Suhu, Kelembaban Dan Kecepatan Angin Air Conditioner (AC) Terhadap Jumlah Angka Kuman Udara Ruangan

<p>A room that uses an Air Conditioner (AC) is one of the breeding grounds for air microorganisms, therefore it is necessary to have a number of germs in the room so as not to cause airborne disease. The purpose of this study was to determine the effect of temperature, humidity, and wind speed on the number of germs in an air-conditioned room. This type of research is an experimental consisting of 3 dependent variables and 1 independent variable with a cross-sectional research design. Laboratory room air samples were taken by the BRAB method, 12 times in a row. Sampling of the air using an air sampling pump. The results of the study showed that there was a fairly close relationship and a significant effect on temperature with the number of germs (p value = 0.005), with a temperature effect of 20.9%. There is a relationship and influence between humidity and germ numbers (p value = 0.000), with a humidity effect value of 31.9%. There is a relationship and influence between wind speed and germ numbers (p value = 0.009), with a wind speed effect of 18.5%. There is a simultaneous effect of temperature, humidity, and wind speed on the germ number of 33.6%.</p>

Simultaneous effect of temperature, shrinkage, and self-weight creep on RC beams: A case study

This study presents the results of long-term field measurement of two RC beams under the simultaneous effect of medium to high temperature, shrinkage, and self-weight creep. In industrial complexes such as steel making plants, these members may, in addition to creep and shrinkage, be exposed to high temperature. However, less attention has been paid to the simultaneous effect of creep, shrinkage, and temperature in a case study framework. In this regard, two RC beams with the same geometric properties in a pelletizing plant located in Kerman, Iran, were studied. In addition, in order to establish a powerful numerical method for these effects, numerical results were compared with the field measurement data. The results showed that an average increase by 50% in temperature would increase the maximum deflection of RC beam by 37%. In the case of the environment temperature, grate machine temperature increased the maximum deflection of RC beam by 61%. Moreover, field measurements showed that for self-weight creep level, shrinkage, temperature, and cracking strains covered more than 80% of the total strain. Similarly, such as this case study, simultaneous effects of these triple factors can change the long-term serviceability of structural elements exposed to harsh environmental conditions.

On the simultaneous effect of temperature, pressure, water content and space–time on acrylic acid production from propane

An attractive route for producing acrylic acid is the direct partial oxidation of propane for which, MoVTeNb-based mixed oxides have exhibited promising results. In this work, formal design of experiments (DOE) is applied to investigate the simultaneous impact of four key independent reaction variables (factors): temperature (613–693 K), pressure (4–55 kPa–g), space–time (55–167 gcath/mole) and water content in the feed (0–20 mole%) on the performance of a MoVTeNb-based catalyst to produce acrylic acid from propane. Catalytic experiments are performed in a lab-scale fixed-bed reactor feeding a gaseous mixture containing propane, oxygen, nitrogen and water. DOEs results are analyzed by combining graphical (main effects and interaction plots) and statistical tools (ANOVA, regression analysis as well as surface responses). Most of the factors accounted for in the DOEs have a linear effect on propane conversion and a quadratic effect on acrylic acid selectivity; binary interaction between factors is common for acrylic acid selectivity. Water addition to the reaction mixture is essential to improve acrylic acid selectivity. Regression models predict that adding 18 mole% of water to the feed maximizes acrylic acid selectivity when operating at moderate levels of temperature (648 K) and pressure (10 kPa-g). Also, operation at high severity in pressure, medium severity in space–time and low-medium severity in temperature increases further acrylic acid selectivity.

Synergistic inhibition behavior of sodium tungstate and penicillin G as an eco-friendly inhibitor on pitting corrosion of 304 stainless steel in NaCl solution using Design of Experiment

In this study the synergistic behavior of sodium tungstate and penicillin G as an environmental-friendly co-inhibitor on pitting corrosion of 304 stainless steel in 3.5 wt% NaCl solution has been investigated. The simultaneous effect of temperature and inhibitor on inhibition efficiency has been evaluated by employing Design of Experiment technique according to Central Composite Design method. The temperature and concentration of inhibitors were selected as independent factors, while the extent of passive region and inhibition efficiency were considered as the responses of independent factors. Cyclic potentiodynamic polarization and electrochemical impedance spectroscopy were employed to determine the responses experimentally. The surface morphology and chemical composition of surface film were characterized by a Scanning Electron Microscope. The electrochemical measurements showed that increase in the concentration of penicillin G up to 50 ppm as co-inhibitor in the presence of 2.5 mM sodium tungstate resulted in the highest possible extent of passive region and inhibition efficiency. The increase in the extent of passive region and inhibition efficiency due to addition of penicillin G as co-inhibitor to sodium tungstate showed the synergistic behavior of the mixed inhibitors in controlling pitting corrosion of 304 stainless steel. It was revealed that the extent of passive region and inhibition efficiency decrease by increase in temperature of the solution due to increase in the kinetics of corrosion reactions and desorption of inhibitor from surface. The SEM observations indicated that the mixed inhibitors could provide a smooth and uniform surface due to formation of a protective film.

Icosahedral AlCuFe quasicrystal at high pressure and temperature and its implications for the stability of icosahedrite.

The first natural-occurring quasicrystal, icosahedrite, was recently discovered in the Khatyrka meteorite, a new CV3 carbonaceous chondrite. Its finding raised fundamental questions regarding the effects of pressure and temperature on the kinetic and thermodynamic stability of the quasicrystal structure relative to possible isochemical crystalline or amorphous phases. Although several studies showed the stability at ambient temperature of synthetic icosahedral AlCuFe up to ~35 GPa, the simultaneous effect of temperature and pressure relevant for the formation of icosahedrite has been never investigated so far. Here we present in situ synchrotron X-ray diffraction experiments on synthetic icosahedral AlCuFe using multianvil device to explore possible temperature-induced phase transformations at pressures of 5 GPa and temperature up to 1773 K. Results show the structural stability of i-AlCuFe phase with a negligible effect of pressure on the volumetric thermal expansion properties. In addition, the structural analysis of the recovered sample excludes the transformation of AlCuFe quasicrystalline phase to possible approximant phases, which is in contrast with previous predictions at ambient pressure. Results from this study extend our knowledge on the stability of icosahedral AlCuFe at higher temperature and pressure than previously examined, and provide a new constraint on the stability of icosahedrite.

Simultaneous effect of temperature and pressure on catalytic hydrothermal gasification of glucose

Gasification of glucose in near- and supercritical water was investigated at temperature and pressure ranges from 400 to 600°C and 20 to 42.5MPa with a reaction time of 1h. Hydrothermal gasification of glucose was performed in the absence and presence of catalyst (K2CO3) in a batch reactor. The influences of temperature and pressure in the supercritical regimes of water, catalyst were examined in relation to the yield and composition of the gases and aqueous products. The product gases were analyzed by gas chromatography, and the aqueous products were analyzed by high performance liquid chromatography. The gases produced were carbon dioxide, methane, hydrogen, carbon monoxide, and C2–C4 hydrocarbons and there was significant production of aqueous products and residue. The aqueous products composed of oxygenated compounds, including carboxylic acids (glycolic acid, formic acid, acetic acid), furfurals (furfural, 5-hydroxymethyl furfural, 5-methyl furfural), phenols (phenol, methyl phenols, hydroxy phenols, methoxy phenols), aldehydes (formaldehyde, acetaldehyde, acetone, propionaldehyde), ketones (3-methyl-2-cyclo-pentene-1-one, 2-cyclo-pentene-1-one) and their alkylated derivatives. Carbon gasification efficiencies were improved by addition of K2CO3 into the reacting system. Carbon gasification efficiency reached maximum (94%) at 600°C and 20MPa. The yield of hydrogen among gaseous products increased with increasing temperature and decreasing pressure.

Efeito da temperatura e da concentração nas propriedades físicas da polpa de melancia

Density and viscosity are important physical properties since they are the properties most used in calculations involving fluid transport. The main objectives of the present study were to examine the rheological behaviour and determine the density of watermelon pulp at different temperatures (10, 20, 30, 40, 50 and 60 °C) and concentrations (8, 17, 26 and 35 °Brix) and to obtain models to describe the alterations in these physical properties as a function of temperature and concentration. A Searle concentric cylinder rheometer was used to study the rheological behaviour and the density was determined using pycnometers. The models used in this work were fitted by nonlinear regression. It was concluded that the watermelon pulp behaved as a pseudoplastic non-Newtonian fluid at all the temperatures and concentrations used and that the Ostwald-de-Waele model could be used to describe this behaviour. Models were found that described the simultaneous effect of temperature and concentration on the density and viscosity of watermelon pulp, and these could be very useful in the food industry.

Ageing Effect on the Properties of Tri-Layer Polyethylene Film Used as Greenhouse Roof

This work aims at studying the degradable effect of natural and artificial ageing on tri-layer polyethylene films used as greenhouse cover in the North Africa environment. The film was supplied by Agrofilm and made of low density polyethylene (LDPE), containing additives (e.g., color and infrared IR and ultraviolet UV stabilizers). This film was used to build a real greenhouse located in the North of Algeria. Impact of ageing was monitored by observing the changes in mechanical (strength and ductility) properties. The study has been carried out over a period of eight-months of natural and artificial ageing. The films have been artificially aged at 40°C, 40°C + UVA, 50°C and at 50°C + UVA. The findings show that the environmental factors have degradable effects on the durability and all properties of the polyethylene film. The study revealed also that the degradation parameters measured are directly related to criteria for evaluating the effectiveness of agricultural greenhouse. The simultaneous effect of temperature and UVA radiation induced the most significant degradation on the film surface and consequently a reduction in the lifetime of the material. © 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of ICM11

Simultaneous effect of temperature, cyanide and ammonia-oxidizing bacteria concentrations on ammonia oxidation

For biological nitrification, a set of experiments were carried out to approximate the response of lag period along with ammonia oxidation rate with respect to different concentrations of cyanide (CN-) and ammonia-oxidizing bacteria (AOB), and temperature variation in laboratory-scale batch reactors. The effects of simultaneous changes in these three factors on ammonia oxidation were quantitatively estimated and modeled using response surface analysis. The lag period and the ammonia oxidation rate responded differently to changes in the three factors. The lag period and the ammonia oxidation rate were significantly affected by the CN- and AOB concentrations, while temperature changes only affected the ammonia oxidation rate. The increase of AOB concentration and temperature alleviated the inhibition effect of cyanide on ammonia oxidation. The statistical method used in this study can be extended to estimate the quantitative effects of other environmental factors that can change simultaneously.

Fuel and metabolic scaling during the early life stages of Atlantic cod Gadus morhua

The simultaneous effect of temperature (5, 7, 10 and 13°C) and light on the rates of oxy- gen consumption and ammonia excretion of larval and early juvenile Atlantic cod Gadus morhua was examined. Larvae increased their mean dry body mass by 2000 times within 48 d. Instantaneous growth rate exceeded 30% d -1 towards the end of the study period, and proportionality of growth fol- lowed a triphasic pattern, during which body water content significantly declined but no inflection could be detected in the metabolic exponents. Data were rigorously tested via Model-I (least squares) and Model-II (geometric mean) regression techniques, and the aerobic metabolic rate was found to scale allometrically with both dry and wet body mass. The metabolic exponent was not affected by increasing temperature, but was significantly decreased by the presence of light (b = 0.88 to 0.89 for light-adapted larvae; b = 0.90 to 0.91 for dark-adapted larvae). The effect of light on small larvae (4 to 7 mm standard length, SL) caused a 30 to 40% increase in metabolic rate, while no effect was observed in larger juveniles (40 to 60 mm SL). Acute temperature acclimation of Atlantic cod of 4 to 60 mm SL (0.04 to 350 mg dry mass) demonstrated normal thermal sensitivity with Q10 values of 2.4 for dark-adapted larvae and 2.6 for light-adapted larvae. Rates of ammonia excretion also scaled allo- metrically with wet and dry body mass and showed greater variability in dark-adapted compared to light-adapted larvae. Comparison of the molar rates of ammonia excretion and oxygen consumption revealed that Atlantic cod larvae have a high reliance on amino acids as fuel for energy dissipation. With lipids as the assumed co-substrate, amino acids were estimated to account for 70 to 95% of total substrate oxidation for larvae up to 7 mm SL (first 3 to 4 wk of post-hatch development). Beyond 7 mm SL, the reliance on amino acids as fuel began to decline, but even in juveniles of 40 to 60 mm SL, amino acids still represented the dominant source of fuel. For juveniles of between 10 and 20 mm SL, both the rates of oxygen consumption and ammonia excretion remained unaffected by the presence of food in the gut. For short-term fasted juveniles (35 to 60 mm SL), however, a substantial decline in the rate of ammonia excretion was observed. This indicates that during short-term fasting (8 to 12 h) early juvenile Atlantic cod conserve amino acids, rather than funneling them into the tricarboxylic acid cycle.

Optimization of light and temperature for growing Chlorella sp. using response surface methodology

The simultaneous effect of temperature and photon flux density on microalga Chlorella sp. growth was analysed by response surface methodology of two consecutive full factorial designs. Maximum specific growth rate was 0.128 h-1 at 35°C and 2400 μmol photon m-2s-1. A photoinhibition effect was observed at high photon flux densities with temperatures far below the optimum. Temperature was the main factor affecting specific growth rate.

Influence of Several Parameters on Efficiency and Peak Shape in the Micellar Liquid Chromatography of Polynuclear Aromatic Hydrocarbons

Abstract The influence of different factors on efficiency and peak asymmetry for a wide group of PAHs in micellar liquid chromatography (MLC) is studied. One can see that efficiency increases as the concentration of surfactant in the mobile phase increases. The addition of 2-propanol increases efficiency up to a 15%. The simultaneous effect of temperature and flow rate show the influence of hydrophobicity of solutes on efficiency. H-μ plots show a different behavior of PAHs in MLC as compared to RP-HPLC.

Course of Temperature and Humidity of Air in a Large-scale Barn for Heifer Rearing During the Summer

Fiser A., Hajkova Jana: Course of Temperatures and Humidity of the Air in a Large­ -scale Barn for Heifer Rearing during the Summer. Acta vet. Bmo, 59,1990: 73-85. In the present study of the course of temperatures and humidity of the air in a large-scale barn for heifer rearing, three macroclimatic situations were studied from May to September 1986. The macroclimatic situations are characterized as cold and rainy summer period, pleasant and warm summer period, and hot summer period. In analyses of the three selected macroclimatic situations, the simultaneous effect of temperature and humidity of air in the barn on the housed animals was studied and was expressed as cold, the optimum temperature and humidity, and sultriness. The interrelationships between the outside temperature and humidity and those inside the barn are illustrated in graphs as the so-called average day of the period investigated. The results have shown that a sultry atmosphere is brought about when the outside temperatures reach 17.95°C and occurs in 51.52 % (and/or 78.12 %) of the period of housing the animals in the barn. The relationship between the tem­ perature and humidity was optimal in 78.72 % (and/or 93.88 %) when the average outside air temperature was 1O.90°C; when it was 22.01 °C, a permanent sultry atmosphere was observed in 52.34 % (and/or 58.82 %) of the period of housing the animals in the bam. The dependence on temperature and humidity of the outside air was the greatest during the hot summer period when the average temperature was 22.01°C and relative humidity 63.30 %; this correlating dependence was statistically highly significant. In the other two macroclimatic situations, i.e. average temperatures 17.95°C and 10.90°C, the similarity of the course of curves for temperature and humidity is more expressive only for temperature. Correlation between the ambient temperature of the barn and of the atmospheric outside air was highly significant only during pleasant summer weather in the back half of the bam when the average diurnal temperature reached 17.95°C. The course of the curve of humidity inside the bam is not always similar to that of the outside air. This is connected with ventilation of the front and back halves of the bam, or with the method of removing sources of water vapours, i.e. liquid manure, urine and technological water in the barn. Bioclimate, technology of litter-free housing, temperature, humidity, pressure of water vapours in barn air

Geometrically and physically nonlinear bending of steeply sloping shells with various shapes under simultaneous effect of temperature and external forces

Geometrically and physically nonlinear bending of steeply sloping shells with various shapes under simultaneous effect of temperature and external forces