Course Of Temperature Changes Research Articles

Insecticidal effect of heat treatment in commercial flour and rice mills for the control of phosphine-resistant insect pests

Development of resistance to insecticides and fumigants in several stored product insect pests is of global concern as failure of routine treatment protocols is on the rise, causing serious economic implications. A series of trials in commercial flour and rice mills were conducted to evaluate the effectiveness of heat treatment against two major pest species, as an alternative to fumigant phosphine that has been under serious threat from resistance development in key pest species. Adults and immatures of both susceptible and phosphine-resistant strains of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) were included in the study. The target temperature for the treatment was 50 °C and the treatment lasted for 16–36 h, depending on the building size. Vials containing test insect cohorts along with their preferred diets were placed at pre-determined locations within the trial sites. Wireless sensors were also placed next to test insect vials to record and monitor course of temperature change during the treatment. The adult mortality assessment of test insects was carried out immediately after the termination of each trial. Thereafter, the treated vials containing the diet and immature insect life-stages were shifted to a controlled environment cabinet and maintained at 25 °C and 65% relative humidity for 65 d when the progeny mortalities were assessed. Our results showed that heat treatment had caused very high adult (in most cases 100%) and suppressed progeny mortality in both T. castaneum and S. oryzae in all trials, irrespective of their susceptibility status to phosphine. The current study suggests that heat treatment in rice/flour mills holds potentials to be used as an alternative treatment to phosphine, especially to control phosphine resistant strains.

Impact of Biochar Addition and Air-Flow Rate on Ammonia and Carbon Dioxide Concentration in the Emitted Gases from Aerobic Biostabilization of Waste.

Application of additives to waste may influence the course of the biostabilization process and contribute to its higher effectiveness, as well as to a reduction in greenhouse gas and ammonia (NH3) emission from this process. This paper presents research on the impact of biochar addition on the course of the biostabilization process of an undersized fraction from municipal solid waste (UFMSW) in terms of temperature changes, CO2 concentration in the exhaust gases, NH3 emission from the process, as well as changes in the carbon and nitrogen content in the processed waste. Six different biochar additives and three different air-flow rates were investigated for 21 days. It was found that biochar addition contributes to extending the thermophilic phase duration (observed in the case of the addition of 3% and 5% of biochar). The concentration of CO2 in exhaust gases was closely related to the course of temperature changes. The highest concentration of CO2 in the process gases (approx. 18–19%) was recorded for the addition of 10% and 20% of biochar at the lowest air-flow rate applied. It was found that the addition of 3% or a higher amount of biochar reduces nitrogen losses in the processed UFMSW and reduces NH3 emission by over 90% compared to the control.

Change of Specimen Temperature during the Monotonic Tensile Test and Correlation between the Yield Strength and Thermoelasto-Plastic Limit Stress on the Example of Aluminum Alloys.

This paper presents an attempt to generalize the description of the course of specimen temperature changes during the tensile test and to connect the value of the thermoelasto-plastic limit stress with the value of a clear (physical) or proof strength (offset yield strength) on the example of tests of the following aluminum alloy sheets used in Poland for airplane structures: 2024-T3 and D16 in three grades: D16ATV, D16CzATV, and D16UTV. A thermographic camera was used for specimen surface temperature measurement during the tensile test. The Portevine–Le Chatelier effect (the so-called PLC effect) was observed for tests of specimens cut from sheet plates, which was strongly reflected in the temperature fluctuations. The course of temperature change during tensile tests was divided into four characteristic stages related to the occurrence of a clear or offset yield strength. It was found that if there is a clear yield strength, the value of the thermoelasto-plastic limit stress was greater than this yield strength. If there was an offset yield strength, the value of the thermoelasto-plastic limit stress was lower than this yield strength. The differences in the aforementioned values of individual yield strengths did not exceed several percent. Thus, it can be concluded that the thermoelasto-plastic limit stress determined on the basis of the course of specimen temperature changes during the tensile test is well correlated with the value of the yield strength of the material.

Parameters of the car's brakes work in real operation condition

The article presents the results of measurements and statistical analysis of the variables characterizing the braking process and the work of the car's braking system in diversified operating conditions. The introductory part presents a measuring system that allows measurements of brake system operation parameters during operation. Discussed are the methodology for measuring and determining such values as the temperature of the discs, unit pressures and the slip speed at the contact of the disc and brake pad, braking pressure, vehicle speed and its longitudinal acceleration. Operational working conditions included urban driving, extra-urban and motorway driving. Based on the measurements made, histograms of measured values were developed. On the basis of the obtained results, typical temperature gains during a single braking in individual conditions were determined and the course of temperature changes during cooling of the brake discs was analyzed. The ranges of typical values of the tested parameters for individual operating conditions were generalized and compared with the values characteristic for emergency braking, which can be considered as maximum values.

Assessment of Suitability of the Design of Gating System with the Use of Simulation Software

The quality of thin wall castings produced by metal die-casting depends on the coherence and consistency of various aspects influencing the process of casting cycle. The qualitative properties of castings should already be considered in the design phase of construction of the gating system. The simulation software is an effective facility for the initial revealing of defects of the design phase. The assessment of casting cycle by the means of simulation predicts an incidence of defects of the casting core in the design phase and therefore reduces both the incidence of defects in the production and the costs while the production efficiency is increased. The article deals with the assessment of the design of the gating system for a particular casting type. The filling of mould cavity, casting solidification and time course of temperature changes occurring in the selected locations of gating system were defined as parameters indicating the assumptions of design accuracy. Simulation tests were carried out in the NovaFlow&Solid program. The tests resulted in a conclusion evaluating and describing the adequacy of structural design of the gating system.

Spawning phenology of the white bream (Blicca bjoerkna) in the "Dnieper-Orylskiy" Nature Reserve in relation to seasonal temperature dynamic

Spawning phenology of the white bream (Blicca bjoerkna) in the "Dnieper-Orylskiy" Nature Reserve in relation to seasonal temperature dynamic

Thermal simulation of formation composite layer on model casting process

In this paper the results of thermal simulation of formation composite layer on model cast steel casting process have been presented. The objective of this research was to determine the technological parameters of the formation composite layer process which enables obtaining good quality reinforcement layer of the desirable thickness. For assumed changes of chosen technological parameters, distribution of temperature in model casting as well as course of temperature changes in characteristic point of composite insert have been determined. Simulations have been carried out for two different materials of compositing element (insert) and three different pouring temperatures with software NovaFlow&Solid 2.9 r81. Obtaining good quality composite layer with desirable thickness depends on parameters of the process and level of heating during the casting process. The researches enable determination of the technological parameters that directly influence on this process and the criterions to be met by the casting technology of this kind. The results obtained and their experimental verification will make it possible to form a basis for working out the guidelines and principles for the design technology of casting with composite layer on chosen surfaces productions. [Received 31 March 2006, Accepted in revised form 18 January 2007]

Carbon Monoxide Formation from Volatile Anesthetics Measured during Simulated Clinical Conditions

Carbon Monoxide Formation from Volatile Anesthetics Measured during Simulated Clinical Conditions. Wissing et al. (page 1205)Recent clinical reports of increased carbon monoxide (CO) hemoglobin concentrations in children anesthetized with sevoflurane that had passed through dry soda lime seem to contradict the laboratory experience with this anesthetic. To examine discrepancies between laboratory investigations and clinical experiences, Wissing et al. designed an experiment to measure CO formation from five different volatile anesthetics passed through an absorber system that permitted temperature changes.Experiments were conducted in triplicate. Either 2.5% or 5% of five inhalational anesthetics (desflurane, enflurane, isoflurane, halothane, and sevoflurane) were passed for 2 h through an absorber canister filled with dried soda lime. Baseline CO production was first determined using dry soda lime and a flow of 2 l/min O2with no volatile anesthetic and using fresh wet soda lime and a flow of 2 l/min with 5% anesthetic. CO concentrations were continuously measured at the absorber outlet. Additional experiments were conducted to confirm the sevoflurane results because the magnitude of CO production was unexpected and because of the potential of various breakdown products. CO was detected with all anesthetics passed through dry soda lime, but the time course and rate of CO production and the time course of temperature changes differed between the agents. Measurable amounts of CO were found immediately after desflurane, enflurane, or isoflurane came in contact with the soda lime; with sevoflurane, there was a time delay between contact and CO production. CO production peaked initially and was highest with desflurane, followed by enflurane, isoflurane, sevoflurane, and halothane. The temperature of the absorbent increased with all anesthetics, but was highest for sevoflurane. As a result of these experiments, the researchers caution that although CO production is clearly higher than with other agents, some CO—in possibly relevant amounts—is produced by sevoflurane. Adequate precautions should be taken to ensure that soda lime in absorbers does not become desiccated.

Cholesterol affects physical properties and (Na + ,K + )-ATPase in basolateral membranes of renal and intestinal epithelia from thermally acclimated rainbow trout

Previous work has shown that cholesterol levels are modulated in plasma membranes from some but not all tissues of poikilotherms over the course of temperature change. To gain a better understanding of tissue and membrane domain-specific cholesterol function during thermal adaptation we examined effects of cholesterol on membrane physical properties and (Na+,K+)-ATPase in native and cholesterol-enriched basolateral membranes from kidney and intestine of thermally acclimated trout (Oncorhynchus mykiss). Membrane order (as indicated by fluorescence depolarization studies) is increased, whereas its thermal sensitivity is decreased by elevated cholesterol levels in mem branes with relatively low endogenous amounts of cholesterol (intestinal membranes and renal membranes from cold-acclimated fish). Thermal sensitivities of membrane order in kidney are 1.5-fold higher in native compared with cholesterol-enriched basolateral membranes. For renal plasma membranes, (Na+,K+)- ATPase activity is lowest near the transition between native and surpraphysiological cholesterol levels. Endogenous cholesterol levels (relative to phospholipid contents) in intestinal basolateral membranes from cold-acclimated fish vary more than 1.5-fold; membranes with cholesterol/phospholipid molar ratios of 0.3 have activities of (Na+,K+)-ATPase that are twofold lower than native membranes having a ratio of 0.2. These results suggests that maintenance of cholesterol levels in intestinal basolateral membranes during thermal acclimation may ensure sufficient activity of (Na+,K+)-ATPase. Membrane function in kidney, with its high native cholesterol content, is less likely to be affected by temperature change.

Differential impact of hypothermia and pentobarbital on brain-stem auditory evoked responses

Two experiments were conducted to determine the effects of hypothermia and pentobarbital anesthesia, alone and in combination, on the brain-stem auditory evoked responses (BAERs) of rats. In experiment I, unanesthetized rats were cooled to colonic temperatures 0.5 and 1.0°C below normal. In experiment II, 2 groups of rats were cooled and tested at 37.5, 36.0, 34.5 and 31.5°C. One group was anesthetized during testing and the other group was awake. The rat BAER was sensitive to cooling of 1°C or less. Peak latencies were prolonged and peak-to-peak amplitudes were increased by hypothermia alone. The effect on amplitude may be related to the time course of temperature change or to stimulus level. Pentobarbital significantly affected both latencies and amplitudes over and above the effects of cooling. The specific effects of pentobarbital differed by BAER peak and by temperature. The findings point up the importance of the potential confound of anesthetic drugs in most of the evoked potential literature on hypothermia and, for the first time, quantify the complex interactions between pentobarbital and temperature which affect the BAER wave form.

Osmotic activity of liver cells and melting point of liver.

Depression of the melting point of liver tissue rapidly frozen by liquid nitrogen during life provides a means by which the molecular concentration within liver cells may be compared with that of solutions of sodium chloride or of blood or of blood serum. The rising temperature of frozen blood of guinea pig under the conditions of these experiments is retarded when melting occurs, pursues when plotted a prolonged linear course, and finally rises precipitously at -0.54 degrees C. when melting is complete. With the melting of blood serum of guinea pig and of blood of cat and of rat, the temperature takes approximately the same course. The temperature changes are nearly the same as those of a frozen solution of sodium chloride isotonic with blood serum. The temperature changes of frozen liver assumes when plotted a linear course at about -1.1 degrees C., increases at intervals with step-like progress and finally rises precipitiously at -0.76 degrees C. The temperature changes in melting liver of cat and of rat are similar. The melting of liver begins at a level which approximates that of a solution of sodium chloride isotonic with it. The step-like course of temperature changes which occur during the melting of frozen liver are best explained by the assumption that the cells contain substances which successively and temporarily retard the rise of temperature.