Thermal Characterization of Biofluids for Heat Transfer Fluid in Thermal Transport Technologies

Thermal fluids modulate temperature conditions around the thermal collector systems indirectly by circulating the heat transfer fluid throughout the heat exchanger, thereby simulating cooling and heating with thermal condition. This study investigates biofluid from Moringa oleifera kernel, Date kernel, Palm kernel, Coconut kernel and Mango kernel as base fluids for heat transfer fluid application in solar thermal technology. The methodology employed in this study is experimental and the analyzed biofluids results was compared with conventional heat transfer base fluids. Thermal constant analyzer (TPS-2005S), CT-72 Transparent viscometer and Eagle eye SG-500 portable digital hydrometer were used to measure the thermophysical properties, viscosity, and density, of the biofluids respectfully. From the results, the biofluids showed comparative thermophysical properties to conventional base fluids. Moringa oleifera kernel oil and Mango kernel oil has the best quality among the biofluids with thermal conductivity, specific heat, viscosity, and density value was 0.1698Wm/k, 1984.01J/kg.K, 37.12mm2/s, 874.23kg/m3, and 0.2642Wm/k, 763.18J/kg.K, 45.27mm2/s, 914.22kg/m3, respectively. The biofluids was thermally stable after exposure to several heating cycles and heating temperature as no significant degradation was observed in there thermophysical properties. However, there are needs for further experimental studies on clogging and possibility of enhancement of biofluids with organic nanoadditives.

Thermal energy requirement for tobacco caterpillar Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) development on artificial diet

Development and survival of tobacco caterpillar Spodoptera litura larvae and pupae were studied at each of seven constant temperatures, 15±1, 18±1, 21±1, 24±1, 27±1, 30±1 and 33±1°C, in incubators. Oviposition, in-cubation, larval and pupal periods were recorded at each of the temperatures. The survival from 1st instar to adult emergence ranged between a maximum of 60% at 24°C and 30% at each of 18°C and 33°C. Developmental duration of different larval instars and pupae declined with an increase in temperature from 15 to 33°C. The optimum temperature for larval and pupal survival in S .litura on artificial diet was observed to be 24°C. On the other hand, optimum temperature range for oviposition was observed to be 27-33°C.The relationship between temperature (T) and development rate (r) was established using linear regression to estimate the thermal constant (K) and development threshold (T0).Thermal constant for 1st to 6th larval instars were computed as 76.9, 90.9, 125, 83.3, 62.5, 90.9 and 200 degree days (DD), respectively, with corresponding development thresholds as 12.8, 11.7, 9.8, 10.3, 10, 10.9 and 13.2oC. Single developmental threshold for larval stage was computed as 13°C.These thermal constants and development thresholds can be used in developing mechanistic population simulation model, which in turn will facilitate the assessment of climate change impact on the pest.

Thermal Requirements of Ooencyrtus submetallicus (Hym.: Encyrtidae) and Telenomus podisi (Hym.: Platygastridae) Parasitizing Euschistus heros Eggs (Hem.: Pentatomidae)

Temperature is one of the abiotic factors that strongly influences the biology and behavior of insects. In this study, we assessed the development of egg parasitoids Ooencyrtus submetallicus and Telenomus podisi parasitizing Euschistus heros eggs at different temperatures, and estimated the average number of generations for seven representative soybean-producing regions in Brazil. A comparative biology study was conducted, where the percentage of parasitism and emergence, life cycle duration (egg–adult), and longevity were found to be similar between O. submetallicus and T. podisi. The sex ratio and the number of individuals emerged from parasitized egg were higher in O. submetallicus in all regions. In the study of thermal requirements, temperatures of 16, 19, 22, 25, 28, 31, and 33 °C were tested. O. submetallicus and T. podisi developed at temperatures between 16 and 31 °C. The base temperature (Tb) for O. submetallicus and T. podisi was 9.3 and 6.7 °C, respectively; the thermal constant (K) was 336.9 and 272.7 degree-days, respectively. The estimated average number of annual generations of both parasitoids was higher than the host. O. submetallicus and T. podisi have the same ability to parasitize and develop in eggs of E. heros under the conditions studied. Both parasitoids exhibited satisfactory development and parasitism at temperatures between 19 and 31 °C. The development of both parasitoids was faster than their host, and the number of generations was higher for the seven studied localities.

Influence of Mesocarp Fibre Inclusion on Thermal Properties of Foamed Concrete

The addition of mesocarp fibre as a bio-composite material in foamed concrete can be well used in building components to provide energy efficiency in the buildings if the fibre could also offer excellent thermal properties to the foamed concrete. It has practical significance as making it a suitable material for building that can reduce heat gain through the envelope into the building thus improved the internal thermal comfort. Hence, the aim of the present study is to investigate the influence of different volume fractions of mesocarp fibre on thermal properties of foamed concrete. The mesocarp fibre was prepared with 10, 20, 30, 40, 50 and 60% by volume fraction and then incorporated into the 600, 1200 and 1800 kg/m3 density of foamed concrete with constant cement-sand ratio of 1:1.5 and water-cement ratio of 0.45. Hot disk thermal constant analyser was used to attain the thermal conductivity, thermal diffusivity and specific heat capacity of foamed concrete of various volume fractions and densities. From the experimental results, it had shown that addition of mesocarp fibre of 10-40% by volume fraction resulting in low thermal conductivity and specific heat capacity and high the thermal diffusivity of foamed concrete with 600 and 1800 kg/m3 density compared to the control mix while the optimum amount of mesocarp fibre only limit up to 30% by volume fraction for 1200 kg/m3 density compared to control mix. The results demonstrated a very high correlation between thermal conductivity, thermal diffusivity and specific heat capacity which R2 value more than 90%.

Development of industrial scale reproduction in male sturgeons using Volga sterlet population as an example

The article describes special aspects of reproduction system development in male sturgeons using Volga sterlet population as an example (Acipenser ruthenus Linnaeus, 1758) within industrial enterprise of the Konakovskiy coarse fishery branch of the FSBSI Russian Federation Research Institute Of Fishery and Oceanography (VNIRO). The study results showed that gonad maturation stage I–II is completed at the age of 2 years if the total thermal constant is at least 11 thousand degree-days. Cytological sex differentiation occurs in the formed gland and begins at the age of three years if the thermal constant is more than 15 thousand degree-days. The onset of cytological differentiation can be determined by spermatogenesis waves characterised by intensive development of the male gonad III–VI maturity stages. Semelparity is typical for sturgeons, thus, the wave of spermatogenesis is seasonal, which indicates their limited participation in the spawning season at fish farms with natural water temperature. The knowledge of reproductive system development aspects in male sturgeons as illustrated by Volga sterlet population in the setting of industrial enterprise allows improving the practice of spermatogenesis process management at industrial farms ensuring the production of reproductive products of high fish-breeding quality at the time required for the enterprise. Considering the thermal constants made up by sterlet (males) spawners, it is possible to synchronise fish breeding processes (cycles) when receiving reproductive products from female sterlet and ensure repeated production of reproductive products from the same males in the settings of farms with controlled water temperature (throughout a calendar year). English version of the article is available at URL: https://panor.ru/articles/process-of-development-of-the-reproductive-system-in-male-sturgeon-in-industrial-conditions-on-the-example-of-the-sterlet-of-the-volga-population/68305.html

Effect of Temperature on the Development and Survival of Feltiella Acarisuga (Vallot) (Diptera: Cecidomyiidae) Preying on Tetranychus Urticae (Koch) (Acari: Tetranychidae)

The predatory gall midge, Feltiella acarisuga (Vallot) (Diptera: Cecidomyiidae), is an acarivorous species that mainly feeds on spider mites (Acarina: Tetranychidae). Because of its cosmopolitan distribution and predation efficacy, it is considered an important natural enemy available as a biological agent for augmentative biocontrol. However, despite its practical use, the thermal development and survival response to temperature have not yet been fully studied. In this study, we investigated the stage-specific development and survival of F. acarisuga at seven temperatures (11.5, 15.7, 19.8, 23.4, 27.7, 31.9, and 35.4 °C) to examine the effect of temperature on its lifecycle. All developmental stages could develop at 11.5–31.9 °C, but the performance was different according to the temperature. From the linear development rate models, the lower development threshold and thermal constant of the total immature stage were estimated at 8.2 °C and 200 DD, respectively. The potential optimal and upper threshold temperatures for the total immature stage were estimated as 29.3 and 35.1 °C using a non-linear development model. The operative thermal ranges for development and survival at 80% of the maximum rate were 24.5–32.3 and 14.7–28.7 °C, respectively. Thus, it was suggested that 24.5–28.7 °C was suitable for the total immature stage. In contrast, conditions around 8 °C and 35 °C should be avoided due to the lower development rate and high mortality. Our findings provide fundamental information for an effective mass-rearing and releasing program of F. acarisuga in an augmentative biocontrol program and help to predict phenology.

The Growth Model of Forensically Important Lucilia sericata (Meigen) (Diptera: Calliphoridae) in South Korea

Development of forensically important Lucilia sericata (Meigen) was analyzed in South Korea. Rearing was replicated five times at seven constant temperatures between 20–35 °C to elucidate changes in accumulated degree hours, based on developmental stage and body length, and 2673 individuals were statistically analyzed. The results indicated that the optimum temperature, the base temperature, and the overall thermal constant were 22.31 °C (±1.21 °C, 95% CI), 9.07 °C, and 232.81 ± 23 (mean ± SD) accumulated degree days, respectively. In the minimum ADH models of each development stage, nonlinear regression graphs were parallel at the immature stages. Based on the scatter plot (n = 973) of immature stages using ADH values and body length, the logarithmic model using Log10ADH as the dependent variable was identified as the best fitting regression model. Additionally, the adjusted R2 value and mean square of error were 0.911 and 0.007, respectively. This is the first forensically focused study on the development of L.sericata for the estimation of minimum postmortem interval in South Korea. In future studies, we intend to study the development of other necrophagous fly species and to identify parameters for the determination of age at post-feeding and pupal stages.

Effects of Synthesis Conditions on the Performance of SiO2 Aerogel Prepared by CO2 Supercritical Drying

The article presents an investigation about effects of the synthesis conditions on the performance of silica aerogels. Tetraethyl orthosilicates (TEOS) were selected as the silicon source, and two acid-base catalysts were adopted to catalyze the reaction. CO2 supercritical drying was used to drive out the solvent of alcohols in the wet gels. Semi-transparent monolithic and crack-free SiO2 aerogels were successfully obtained. The solvents were prepared with a ratio of ethyl orthosilicate: absolute ethanol: H2O:HCl:NH3·H2O=1:3:5:3×10-3:4.8×10-3.The single effects of solution pH, water volume, and aging temperature synthesized were investigated. The aerogels were characterized with SEM, specific surface area analysis, thermal constant analysis, thermogravimetric analysis, Raman spectroscopy analysis, N2 adsorption-desorption analysis, and hydrophobic angle test. The as-synthesized silica aerogels have a porosity of 95.6%, a specific surface area of 756.9m2/g, an average pore diameter of 16.22nm, a density of 96.8kg/m2, and a thermal conductivity of 0.02W/(m· K). Hydrophobic silica aerogels were also obtained.

Biological traits of the predatory mirid Macrolophus praeclarus, a candidate biocontrol agent for the Neotropical region

The predatory mirid Macrolophus praeclarus is widely distributed throughout the Americas, and is reported to prey upon several horticultural pest species. However, little is known about its biology, thermal requirements, crop odour preferences, phytophagy, and capability to induce defensive responses in plants. When five temperatures studied (20, 25, 30, 33 and 35°C) were tested and Ephestia kuehniella was used as prey, the developmental time from egg to adult on tomato, was longest at 20°C (56.3 d) and shortest at 33°C (22.7 d). The ability of nymphs to develop to adults decreased as the temperature increased, with the highest number of nymphs reaching the adult stage at 20°C (78.0%) and lowest at 35°C (0%). The lower and upper developmental thresholds were estimated at 11.2° and 35.3°C, respectively. The maximum developmental rate occurred at 31.7°C and the thermal constant was 454.0 ± 8.1 degree days. The highest predation rate of E. kuehniella eggs was obtained at 30°C. In Y-tube olfactory choice tests, M. praeclarus selected tomato, sweet pepper and eggplant odours more frequently than no plant control treatment. Macrolophus praeclarus feeding did not damage tomato plants compared to another zoophytophagous mirid, Nesidiocoris tenuis, which caused necrotic rings. The phytophagy of M. praeclarus induced defensive responses in tomato plants through the upregulation of the jasmonic acid metabolic pathway. The implications of the findings for using M. praeclarus in tomato biological control programmes in the Americas are discussed.

Enhanced Thermal Insulation of the Hollow Glass Microsphere/Glass Fiber Fabric Textile Composite Material

Glass fiber fabrics/hollow glass microspheres (HGM)–waterborne polyurethane (WPU) textile composites were prepared using glass fiber, WPU, and HGM as skeleton material, binder, and insulation filler, respectively, to study the effect of HGM on the thermal insulation performance of glass fiber fabrics. Scanning electron microscopy, Instron 3367 tensile test instrument, thermal constant analysis, and infrared thermal imaging were used to determine the cross-sectional morphology, mechanical property, thermal conductivity, and thermal insulation property, respectively, of the developed materials. The results show that the addition of HGM mixed in WPU significantly enhanced thermal insulation performance of the textile composite with the reduction of thermal conductivity of 45.2% when the volume ratio of HGM to WPU is 0.8 compared with that of material without HGM. The composite can achieve the thermal insulation effect with a temperature difference of 17.74 °C at the temperature field of 70 °C. Meanwhile, the tensile strength of the composite is improved from 14.16 to 22.14 MPa. With these results, it is confirmed that designing hollow glass microspheres (HGM) is an effective way to develop and enhance the high performance of insulation materials with an obvious lightweight of the bulk density reaching about 50%.