Lower Temperature Values Research Articles

Utilização de sistema de resfriamento adiabático evaporativo visando à produção de ovos no Estado do Paraná

The aim of this study was evaluate the use of evaporative cooling system (ECS) of air as an alternative to improve the thermal environment, aiming at egg production (EP) of Rhode Island Red laying hens (2.25 kg). The climatological data of air temperature and relative humidity used to estimate Temperature and Humidity Index (THI) and EP were collected in the IAPAR (Instituto Agronomico do Parana) meteorological field stations from Parana State. The use of ECS of air provides a significant reduction in the THI values, in all locations and periods of the years studied. Considering the average values, the THI of 65.99 can be reduced to 62.52 when it cooling the air. The annual EP ranged from 0.748 and 0.784. When utilizing the ECS of air was possible to get EP between 0.779 and 0.792. In North region, the use of ECS of air results in EP of 0.784, compared to 0.739 without cooling. In this way, the ECS of air provided a significant increase in the annual EP, except to South region, where was observed low annual temperature values.

Crystal Structure Defects of Vanadium Dioxide

The results of X-ray crystallographic investigation and the data on pycnometric specific gravity measurements, as well as low-temperature heat capacity values of vanadium dioxide powder specimens V1±xO2 are discussed within the context of crystal structure defect formation during their synthesis.

Temperature sensibility of the birefringence properties in side-hole photonic crystal fiber filled with Indium

We report on the temperature sensitivity of the birefringence properties of a special kind of photonic crystal fiber containing two side holes filled with Indium metal. The modulation of the fiber birefringence is accomplished through the stress field induced by the expansion of the metal. Although the fiber was made at low gas pressures during the indium infiltration process, the birefringence showed anomalous property at a relatively low temperature value, which is completely different from those reported in conventional-like fibers with two holes filled with metal. By modeling the anisotropic changes induced by the metal expansion to the refractive index within the fiber, we are able to reproduce the experimental results. Our results have practical relevance for the design of devices based on this technology.

Energy and Quality Attributes of Combined Hot-Air/Infrared Drying of Paddy

The kinetics of combined hot-air/infrared thin-layer drying of paddy was studied. The mechanical quality aspects of paddy kernels dried at different drying conditions were evaluated in terms of percentage of cracked kernels and also required failure force obtained from bending tests. The well-known Artificial Neural Network (ANN) modeling technique was applied to predict the drying time, variations in paddy moisture content, the percentages of cracked kernels, and the values of required failure force of paddy at different drying conditions. The best ANN topologies, transfer functions, and training algorithms were determined for prediction of the mentioned parameters. In addition to the product quality aspects, the specific energy consumption (SEC) was estimated for all drying conditions. The results indicated that application of a low-intensity IR radiation (2000 W/m2), together with lower values of inlet air temperature (30°C) and moderate values of inlet air velocity (0.15 m/s), can effectively improve the final quality of paddy (as a heat-sensitive product) with a reasonable SEC.

<b>Temperature of cutaneous and subcutaneous tissue during the application of aerosols in rats

This study compared the thermal changes of cutaneous and subcutaneous tissues exposed to different aerosols. Thirty-six adults Wistar rats were arranged in two treatment groups, one exposed to methyl salicylate (GSM; n = 9 skin and n = 9 subcutaneous) and the other exposed to diclofenac diethylammonium (GDD; n = 9 skin and n = 9 subcutaneous) aerosols. Five jets were applied for one-second through an apparatus to reduce spray dispersion (3 cmdiameter) in the lateral left thigh of the animals. Temperatures were measured every minute (min.) during 30 min., with a digital thermometer. In the skin tissue the sensor was positioned manually, in the subcutaneous tissue it was surgically inserted through the rear face and positioned in the lateral thigh. The skin temperature has homogeneously reduced in both groups. In the subcutaneous tissue the GDD has induced hypothermia from the 2nd to 20th min., the lowest temperature was recorded on the 7th min. (-3.6 ± 0.2ºC in relation to basal). Lowering the temperature by GSM took place from the 1st to 21st min, and the lowest temperature occurred on the 1st min (-9.7 ± 0.5ºC in relation to basal). In the three initial minutes the GSM had temperatures 25, 10 and 5% lower than the GDD. Aerosols have induced hypothermia in the tissues, while the GSM has decreased faster and reached lower values of temperature shown in the subcutaneous tissue.

Band Magnetism with Inter-Site Correlations and Interactions

We introduce the Hamiltonian to describe narrow band electrons. The physics of driving forces towards ferromagnetism is re-examined. Using di erent approximations it has been shown that the magnetic moments created by inter-site interaction and inter-site kinetic correlation decrease quickly with temperature. As a result of these interactions and the realistic density of states the Curie temperatures calculated after tting magnetic moments to their low temperature values are realistic. In the past the Curie temperatures calculated using only the on-site interaction were much higher than the experimental temperatures.

The Eliashberg study of the electron–phonon superconductivity in [formula omitted] compound

The superconductivity in YSn3 is induced by the electron–phonon interaction. The most relevant thermodynamic parameters of the superconducting state for the considered compound have been determined in the framework of the Eliashberg formalism. On the basis of the numerical calculations, it has been shown that the critical temperature (TC) is equal to 6.52K. The obtained result accurately reproduces the experimental value of TC, which is equal to ∼7K. Next, the low-temperature value of the order parameter (Δ(0)) has been determined, as well as the thermodynamic critical field (HC(0)), and the specific heat jump at the critical temperature (ΔC(TC)). It has been found that the dimensionless ratios: RΔ≡2Δ(0)/kBTC,RH≡TCCN(TC)/HC2(0), and RC≡ΔC(TC)/CN(TC), where CN denotes the specific heat for the normal state, take the values fairly exceeding the predictions of the BCS theory. In particular, it has been obtained: 3.97, 0.149 and 2.19, respectively. Let us note that the theoretical result for RC is in agreement with the existing experimental data.

Main-chain sulphur containing water soluble poly(N-isopropylacrylamide-co-N,N′-dimethylacrylamide sulphide) copolymers via interfacial polycondensation

Here, we report the first synthesis of water soluble poly(N-isopropylacrylamide-co-N,N′-dimethylacrylamide sulfide) copolymers via conventional interfacial polycondensation method using phase transfer catalyst (PTC). The effect of various kinds of PTC having different aliphatic chain length and counter ion were employed to examine the kinetics of polysulfide polymer formation. The reactivity ratios, determined employing extended Kelene–Tüdös method using feed composition obtained from 1H NMR analysis, suggest that N-isopropylacrylamide (NIPAM) is more reactive than N,N′-dimethylacrylamide (DMA) in both mono- and di-sulfide polymers. Thermal transition behavior investigated by differential scanning calorimetry (DSC) demonstrated that as the sulphur rank of the sulfide main chain linkages increased, the flexibility of the polymers increased reflected by lower glass transition temperature (Tg) values. The thermal degradation behavior and the major degradation products have been characterized by thermogravimetric analysis (TGA) and electron-impact mass spectroscopy (EI-MS), respectively. Both the studies reveal that the degradation takes place due to weak-link scission of the polymeric main chain. Solubility in water and in most of the common organic solvents even after the sulphur rank increased from 1 to 2 in the main chain, is expected to render potential applications in biological field as well as in industry for these interesting new class of polymers.

Coulomb corrections to experimental temperatures and densities in Fermi-energy heavy-ion collisions

The quantum-fluctuation method using Coulomb corrections is explored to extract temperatures and densities of hot nuclear systems produced in Fermi-energy heavy-ion collisions. The role of the neutron-proton asymmetry of the system was investigated. Temperature values were observed to not depend on the system neutron-proton asymmetry while a clear dependence is seen for density values. Coulomb corrections have been shown to lower temperature values by almost 2 MeV. On the other hand, density results exhibit a small variation.

Experimental investigation on finish intermittent turning of UNS M11917 magnesium alloy under dry machining

An experimental investigation on finish intermittent turning of UNS M11917 magnesium alloy under dry machining is presented. The objective of the study is the analysis of the chip morphology, surface quality and temperature when varying cutting conditions. The intermittent cutting process is analysed using three different workpieces (one continuous and two discontinuous). The experimental plan is based on full factorial designs. Main results of the investigation include the identification of the feed rate as the most important parameter to explain the surface roughness, while no clear influence was found for the cutting speed and slot width. The maximum temperature measured on the tool during the tests was below 50 °C in all of the tests. These low temperature values are explained by the low machining times, depths of cut and cutting speeds used. Thus, for the range of the cutting parameters tested, finish operations can be performed using dry machining under safe conditions. In addition, it was identified that the increase of the depth of cut and feed rate led to higher maximum temperatures, while the increase of the slot width led to lower values. Finally, the morphology of the chips can be classified as segmented chips, including the arc, elemental and spiral chips. Thus, in terms of machining, these chips can be considered as favourable, but, in terms of ignition, these chips are more likely to ignite.

A simple and effective approach for the treatment of dyslipidemia using anionic nanoliposomes

The present study was undertaken to evaluate the anti-dyslipidemic effects of nanoliposomes with different phospholipid compositions. Three sets of liposomal formulations (20Mm; 100nM in size) were prepared with low (SPC), medium (POPC) and high (HSPC) phase transition temperature values with and without cholesterol and anionic phosphatidyl glycerol (HSPC/DSPG; POPC/DMPG; SPC/EPG). The liposomal preparations were characterized for their size and zeta potential (dynamic light scattering), J774A.1 macrophages uptake (flow cytometry) and lipid-modifying effects (tyloxapol-induced hyperlipidemic mouse model). Anionic formulations displayed the highest rate of uptake by macrophages. Among them, HSPC/DSPG and SPC/EPG liposomes had the best lipid-modifying activity. These two formulations exerted favorable impact on all lipid profile parameters by reducing LDL-C (by up to 76% [HSPC/DSPG] and 86% [SPC/EPG]), total cholesterol (by up to 52% [HSPC/DSPG] and 68% [SPC/EPG]), triglycerides (by up to 88% [HSPC/DSPG] and 73% [SPC/EPG]), apoB (by up to 44% [HSPC/DSPG] and 35% [SPC/EPG]) and elevating HDL-C (by up to 85% [HSPC/DSPG] and 75% [SPC/EPG]) concentrations. Atherogenic indices were also effectively reduced following HSPC/DSPG (by up to 69%) and SPC/EPG (by up to 79%) injections. Empty, cholesterol-free nanoliposomal formulations containing 75% anionic phospholipid (PG) might serve as effective and rapid acting anti-dyslipidemic agents. Further research is warranted to confirm the observed anti-dyslipidemic effects of anionic nanoliposomes in diet-induced hyperlipidemic models, and also to evaluate the potential protective effects in regressing atheromatous lesions.

Production and characterization of cornstarch/cellulose acetate/silver sulfadiazine extrudate matrices

The production and evaluation of cornstarch/cellulose acetate/silver sulfadiazine extrudate matrices are reported herein. The matrices were melt extruded under nine different conditions, altering the temperature and the screw speed values. The surface morphology of the matrices was examined by scanning electron microscopy. The micrographs revealed the presence of non-melted silver sulfadiazine microparticles in the matrices extruded at lower temperature and screw speed values. The thermal properties were evaluated and the results for both the biopolymer and the drug indicated no thermal degradation during the melt extrusion process. The differential scanning analysis of the extrudate matrices showed a shift to lower temperatures for the silver sulfadiazine melting point compared with the non-extruded drug. The starch/cellulose acetate matrices containing silver sulfadiazine demonstrated significant inhibition of the growth of Pseudomonas aeruginosa and Staphylococcus aureus. In vivo inflammatory response tests showed that the extrudate matrices, with or without silver sulfadiazine, did not trigger chronic inflammatory processes.

Synthesis, characterization and heat capacities of ternary oxides in the Ti–Nb–O system

Abstract Three different ternary oxides TiNb2O7, Ti2Nb10O29 and TiNb24O62 were prepared by solid-state reaction route and characterized by X-ray powder diffraction method. The standard molar heat capacities of these oxides were measured in the temperature range 125–850 K using differential scanning calorimetry. Since, the deviation from additive oxide was found to be insignificant, the low temperature values were extrapolated to 0 K using Debye extrapolation method and smoothed heat capacities data for temperature range 0–850 K were generated using a six-term fitting equation based on Debye and Einstein functions. By employing these smoothed heat capacities data the thermodynamic data tables were generated for all three oxides.

Multi-pulsed high hydrostatic pressure inactivation of microorganisms: A review

Multi-pulsed high hydrostatic pressure (mpHHP) treatment, which has been applied for two decades, is broadly more effective than the classical or single-pulsed HHP (spHHP) for inactivation of viruses, yeasts, bacterial cells, and fungal and bacterial spores. The effectiveness of the mpHHP treatment could be increased with a smart choice of pressure, initial and target temperature, pulse number, pulse holding time, and compression and decompression rates. The effectiveness of the mpHHP treatment is well documented and at the moment it seems that it is not feasible to apply the mpHHP treatment commercially for the food industry. However, with the availability of new technologies it may be possible to speed up the HHP processing by decreasing compression and decompression rates and to produce repeated pulses of high pressure. The mpHHP treatment could be very beneficial to the food industry and could replace the pressure-assisted thermal sterilization (PATS) with lower pressure and temperature values. Most of the studies have shown that the mpHHP treatment could be used to inactivate the microrganisms in foods at lower pressure values than the spHHP treatment for the same amount of holding time but for a longer processing time (including the compression and decompression periods of the pulses). The mpHHP treatment has a potential to sterilize the food products with the help of developing technology if the optimization between pressure, temperature, number of pulses, pulse holding time and compression and decompression rates could be possible. • This contribution compiles the studies about the mpHHP inactivation of microorganisms. • The mpHHP treatment inactivates the viruses, yeasts, bacteria and spores effectively. • Pulse number, pulse holding time, and compression and decompression rates are important factors during the mpHHP treatment.

Effect of Temperature on the Growth and Ochratoxin A Production of the Aspergillus section Nigri Members Isolated from Dried Figs

AbstractThis study investigated the effects of temperature and incubation time on the growth and ochratoxin A production of three isolates of Aspergillus carbonarius and one Aspergillus niger agg. isolate obtained from dried figs. Optimum growth for all isolates were at 30C while minimum lag phase durations for A. carbonarius isolates were at 25C and for A. niger agg. at 30C. For ochratoxin A (OTA) production, lower optimum temperature values were determined for Aspergillus section Nigri members in comparison to growth temperature. Optimum OTA production was observed at 15–20C and 25C by A. carbonarius and A. niger agg., respectively. Significant amounts of OTA could be accumulated after 3 or 5 days of incubation depending on the isolates. Temperature significantly influenced the growth rate and the extension of lag phase and OTA production of all tested isolates (P < 0.05), whereas incubation time was only significant for OTA production by A. niger agg.Practical ApplicationsThis study contributes to a better understanding of the effect of temperature and incubation time on ochratoxin A (OTA) production of the Aspergillus section Nigri isolated from dried figs. Our results indicated that Aspergillus section Nigri members isolated from dried figs are able to grow and produce OTA in a wide range of temperature (15–40C), and also A. carbonarius may be the main source of OTA in dried figs because of their higher OTA production capacities. Only 3 or 5 days of incubation were required for OTA accumulation, so the length of drying and storage processes could provide sufficient time for the growth and accumulation of OTA in dried figs. Our results may help develop management strategies and drying methods at constant temperature to reduce OTA contamination on dried figs.

Research and Analysis on the Heating Energy Consumption of Urban Residents in Hot Summer and Cold Winter Area of China

The paper analyzes the energy-saving mode in hot summer and cold winter area through simulating and comparing the unique climate conditions and energy-using mode in this region, which are different from the northern heating areas. In hot summer and cold summer areas, the current per unit area value of heating electricity is low in urban residences, but it is based on the low heating temperature value and intermittent heating approach, and the energy consumption grows with the development of economy and the improvement of people's living standard. According to the regional climate characteristics and living mode, the decentralized efficient heating modes based on various pumps should be developed instead of central heating or central heating and cooling system.

Renormalization of QED Near Decoupling Temperature

We study the effective parameters of QED near decoupling temperatures and show that the QED perturbative series is convergent, at temperatures below the decoupling temperature. The renormalization constant of QED acquires different values if a system cools down from a hotter system to the electron mass temperature or heats up from a cooler system to the same temperature. At T = m, the first order contribution to the electron self-mass, δm/m is 0.0076 for a heating system and 0.0115 for a cooling system and the difference between two values is equal to 1/3 of the low temperature value and 1/2 of the high temperature value around T~m. This difference is a measure of hot fermion background at high temperatures. With the increase in release of more fermions at hotter temperatures, the fermion background contribution dominates and weak interactions have to be incorporated to understand the background effects.

Large-n approach to thermodynamic Casimir effects in slabs with free surfaces.

The classical n-vector ϕ{4} model with O(n) symmetrical Hamiltonian H is considered in a ∞{2}×L slab geometry bounded by a pair of parallel free surface planes at separation L. Standard quadratic boundary terms implying Robin boundary conditions are included in H. The temperature-dependent scaling functions of the excess free energy and the thermodynamic Casimir force are computed in the large-n limit for temperatures T at, above, and below the bulk critical temperature T_{c}. Their n=∞ limits can be expressed exactly in terms of the spectrum and eigenfunctions of a self-consistent one-dimensional Schrödinger equation. This equation is solved by numerical means for two distinct discretized versions of the model: in the first ("model A"), only the coordinate z across the slab is discretized and the integrations over momenta conjugate to the lateral coordinates are regularized dimensionally; in the second ("model B"), a simple cubic lattice with periodic boundary conditions along the lateral directions is used. Renormalization-group ideas are invoked to show that, in addition to corrections to scaling ∝L{-1}, anomalous ones ∝L{-1}lnL should occur. They can be considerably decreased by taking an appropriate g→∞ (T_{c}→∞) limit of the ϕ{4} interaction constant g. Depending on the model A or B, they can be absorbed completely or to a large extent in an effective thickness L_{eff}=L+δL. Excellent data collapses and consistent high-precision results for both models are obtained. The approach to the low-temperature Goldstone values of the scaling functions is shown to involve logarithmic anomalies. The scaling functions exhibit all qualitative features seen in experiments on the thinning of wetting layers of {4}He and Monte Carlo simulations of XY models, including a pronounced minimum of the Casimir force below T_{c}. The results are in conformity with various analytically known exact properties of the scaling functions.

Do Boreal Forests Need Fire Disturbance to Maintain Productivity?

Fire is considered as a major driver of ecosystem processes of the boreal forest with important effects on soil and forest productivity. When the interval between successive forest fires is long, a thick organic layer can develop and eventually interfere with processes involved in tree nutrient uptake. We thus hypothesized that the organic layer of well-drained boreal stands increases with time since last fire and that thick organic layers are associated with low values of soil temperature, nutrient availability, and site productivity. This was tested on a chronosequence composed of 90 boreal stands ranging from 1 to more than 2000 years after fire within which we measured organic layer thickness (OLT), mineral soil and foliage nutrient concentrations, soil temperature, ground cover of Sphagnum sp. and Ericaceae sp., leaf area index, aboveground biomass production, and growth efficiency index (GEI). The OLT increased during the first 64 years after fire but stayed statistically constant thereafter. This initial increase in OLT was accompanied by an increase in the C/N ratio and decreases in soil temperature, foliar N, and GEI. The absence of a significant decrease in productivity from 80 to 2000 years post-fire suggests that these characteristics reach a steady state early in the chronosequence that persists in the absence of major disturbances or changes in site conditions. These results imply that management practices may not be necessary to maintain boreal forest productivity in the absence of fire on well-drained sites.

Safer Lithium Battery Electrolyte Systems Based on Organic Solvent-Ionic Liquid Mixtures

The low safety of the actually commercially available lithium-ion batteries represents their main drawback because of the presence of flammable and volatile organic solvents in the electrolyte, resulting in possible fire and/or explosion of the electrochemical device. A very promising approach to solve this problem is the partial or the total replacement of the organic solvents with a new class of fluid materials called ionic liquids (ILs), e.g., molten salts at room temperature or below.Despite their undoubtedly favorable characteristics (non- flammability, negligible vapor pressure, high chemical/ electrochemical/thermal stability), the conductivity of IL-based electrolytes is, however, still lower than that of the organic solutions, with a negative effect on the high rate performance of the electrochemical device. In this scenario, mixtures of ILs in combination with organic compounds have been proposed as electrolyte components for lithium batteries. Such an approach represents a very good compromise between high ionic conductivity (low viscosity) and high safety (low flammability) of the resulting electrolyte [1]. IL materials based on the pyrrolidinium (PYR1A) cations and bis(trifluoromethanesulfonyl)imide (TFSI) anion have been found to be suitable as components for lithium battery electrolyte systems [1].Here is reported a physicochemical investigation on mixtures composed by a lithium salt (LiTFSI), two of the most common organic solvents employed in lithium-ion battery systems (namely EC and EC) and a pyrrolidinium TFSI ionic liquid (namely PYR13TFSI). These quaternary mixed electrolytes, investigated in terms of thermal, transport, rheological and flammability properties, were optimized modulating the ratio of the different components in way to achieve the best physicochemical characteristics.The DSC heating trace of the (0.1)LiTFSI-(0.9-x)PYR13TFSI-(x)EC/DEC mixtures are depicted in Figure 1. A progressive shift of the endothermic feature, due to the melting of the sample, towards lower temperatures is observed with increasing the EC/DEC mole fraction. This behavior may be addressed to a loss in ionicity of the electrolytic mixture. Furthermore, the presence of organic solvents interferes with the Li+ --- TFSI-interactions ions, e.g., by solvation of the lithium cations.The transport properties of the (0.1)LiTFSI-(0.9-x)PYR13TFSI-(x)EC/DEC mixtures are reported in Figure 2 as conductivity vs. temperature dependence. The progressive replacement of PYR13TFSI ionic liquid with EC/DEC results in increasing conductivity raise and in melting point decrease, this latter issue revealed by the shifting of the change slope of the conductivity plot to lower temperature values (in good agreement with the DSC data). At the same time, the increasing fraction of organic solvents progressively reduces the viscosity of the mixtures, resulting in enhanced ion mobility and, therefore, faster transport properties. The gain in ion conduction is much evident at low temperatures because of the melting point raise of the electrolytic mixtures with the EC/DEC content. Conductivity values interest for practical applications are matched at -20°C and -30°C for EC/DEC fractions equal to 0.3 and 0.5, respectively.Finally, ignition tests have revealed the full non-flammability of the electrolyte mixtures for EC/DEC mole fraction up to 0.3. Therefore, this represents the optimal compromise among fast ion transport properties and non-flammable characteristics.Figure 1. DSC trace of quaternary (0.1)LiTFSI-(0.9-x)PYR13TFSI-(x)EC/DEC electrolyte mixtures. The EC:DEC weight ratio was kept equal to 1:1.Figure 2. Ionic conductivity vs. temperature dependence of quaternary (0.1)LiTFSI-(0.9-x)PYR13TFSI-(x)EC/DEC electrolyte mixtures. The EC:DEC weight ratio was kept equal to 1:1.AcknowledgementsThe financial support of the Italian Ministry of Economic Development (MSE), within the Program Agreement ENEA-MSE on Electric System Research, is kindly acknowledged.