Influence Of External Temperature Research Articles

Sensitivity enhanced electric field sensing with etched tilted fiber Bragg grating and a liquid crystal

A temperature-insensitive electric field sensor utilizing HF-etched tilted gratings in a high refractive index solution (E7 liquid crystal) is proposed. The electric field causes a change in the original arrangement of molecules, thereby altering the refractive index of liquid crystals. This study demonstrates that a combination of liquid crystal and HF-etched tilted gratings effectively excites the cladding leakage mode of the tilted grating. Compared to a non-etched tilted fiber Bragg grating, the proposed sensor exhibits higher sensitivity to electric fields. The experimental results show that the electric field sensitivity of a tilted grating with a diameter of 17.7 µm is 0.024 dB/(kV/cm). The influence of external temperature on the electric field sensor of this design is relatively small, only showing a sensitivity of 0.003 dB/°C. This characteristic is very attractive in practical applications such as industry and healthcare.

Understanding Seepage in Levees and Exploring the Applicability of Using an Optical-Fiber Distributed Temperature System and Smoothing Technique as a Monitoring Method

This study aimed to experimentally understand the seepage mechanism in levees and evaluate the applicability of an optical-fiber distributed temperature system based on Raman-scattered light as a levee stability monitoring method. To this end, a concrete box capable of accommodating two levees was built, and experiments were conducted by supplying water evenly to both levees through a system equipped with a butterfly valve. Water-level and water-pressure changes were monitored every minute using 14 pressure sensors, while temperature changes were monitored using distributed optical-fiber cables. Levee 1, composed of thicker particles, experienced a faster water pressure change, and a corresponding temperature change was observed due to seepage. While the temperature change inside the levees was relatively smaller than external temperature changes, measurement fluctuations were significant. Additionally, the influence of external temperature and the dependence of temperature measurements on the levee position made intuitive interpretation challenging. Therefore, five smoothing techniques with different time intervals were examined and compared to determine their effectiveness in reducing outliers, elucidating temperature change trends and enabling the comparison of temperature changes at different positions. Overall, this study confirmed that the optical-fiber distributed temperature system combined with appropriate data-processing techniques can be more efficient than existing methods for understanding and monitoring levee seepage.

Thermoelectric Printhead Cooler for a Stable Process and Curing Control in RTV-2 Silicone Additive Manufacturing by Direct Ink Writing

The direct additive manufacturing, such as Direct Ink Writing (DIW), of silicone parts holds cost and complexity advantages. However, for extruding strands of low viscosity heat curing silicone rubbers, a build plate temperature of up to 90°C is used, which comes with the challenge of early vulcanization inside the printhead. Thus, this paper presents a thermoelectric cooler for universal printheads. At a build plate temperature of 90°C it prolongates vulcanization by 198.5 % (∆tpot life = 508.8 s), which allows a reduction of print speed for higher quality. Additionally, the influence of external temperature is reduced and the viscosity can be controlled.

Application of Temperature Compensation Combined with Neural Network in Infrared Gas Sensor

Due to the state of the gas to be measured, the detection mechanism of the pyroelectric detector and the temperature drift of the peripheral circuit components and the detection of the ambient temperature will interfere with the measurement accuracy of the nondispersive infrared gas sensor from many aspects. This paper proposes a temperature compensation method based on the BP neural network. The compensation function of the gas sensor is realized by programming the various functional parameters in the neural network through the program provided in the Matlab neural network toolbox. Experimental simulation results show that the proposed method effectively reduces the influence of external temperature on the gas sensor output and improves its accuracy and stability.

Seasonal influence of temperature on changes in the frequencies of standing waves of structures according to seismic observations

Buildings and structures are objects of increased responsibility. Under certain conditions, they are subject to negative impacts caused by the impact of various natural and man-made factors on them. It is necessary to monitor both the technical condition of the object and the dynamic influences acting on it, possibly carrying danger both for the structure and for its parts. SEF USGS RAS has developed a method for continuous monitoring of the physical condition of structures, which allows determining the values of natural frequencies of structures from records of a continuously recording seismic station and, if significant deviations from their initial values are detected, drawing conclusions about the condition of structures. reasons for changing the dynamic state of the structure. This study will show the results of such work within the framework of the infrastructure of the Akademgorodok of Novosibirsk, where the results of observations of the natural oscillation frequencies of several residential buildings are presented. During the observations, the influence of external temperature on them was revealed - an increase in ambient temperature leads to an increase in the values of the frequency of natural oscillations, and a decrease in temperature leads to a decrease in values. The greatest change in the frequency of natural vibrations of buildings occurs in summer, at temperatures above 30 degrees C, when there is a great contrast between daytime and nighttime temperatures.

Techno-economic model to appraise the use of cattle manure in biodigesters in the generation of electrical energy and biofertilizer

The increase in dependence on electrical energy has become critical during the last decades. This paper proposes a model to evaluate the technical and economic viability of electrical energy and biofertilizer generation from cattle manure in biodigesters. In the technical phase, the relevant aspects of this process were investigated, such as raw material (type and quantity), the influence of external temperature, the hydraulic retention time of the system, the amount of energy generated and the reduction of energy costs. In the first step of the economic phase, the Investment Projects (IPs) were ranked under the Net Present Value (NPV) criterion. Next, the deterministic Expanded Multi-Index Methodology (EMIM) was applied on the IPs with positive NPV. Finally, the IPs with high sensitivity were analyzed through Monte Carlo Simulation. We validated the model on a rural property in Southeast Parana state in Brazil. Three biodigester systems were compared under ten power levels: cattle manure mono-digestion (Project A), cattle manure/corn co-digestion (60:40 mixture - Project B) and cattle manure/grass co-digestion (60:40 mixture - Project C). The production of energy in the three evaluated systems presented economic advantages, as the size of the system increases due to the economy of scale. Therefore, the combination of system biodigester and power was essential to ensure the project viability.

Thermomechanical analysis of nitinol memory alloy behavior

Shape memory alloys are functional materials characterized by the effect of shape memory and superelasticity. Due to these properties, they are widely used, particularly, in bioengineering, aeronautics, robotics and civil engineering. The temperatures of phase transformations and the influence of external temperature and strain rate on the functional and mechanical characteristics of Ni55.75Ti44.15 shape memory alloy are investigated in this paper. The temperature of alloy phase transformations is obtained by differential scanning calorimetry (DSC) in the temperature range from -70°C to 70°C. Diagrams of differential scanning calorimeters at different heating and cooling rates of Ni55.75Ti44.15 alloy is constructed and analyzed. Samples for mechanical tests are made of round rod 8 mm in diameter. The samples working area is 12.5 mm in length and 4 mm in diameter. Mechanical tests are carried out at temperatures close to the maximum value of the completion temperature of martensitic-austenitic transformation Af = 14.7°C. Diagrams of deformation under uniaxial tension are constructed and stresses of phase transformations, Young's modulus and relative elongations of transformation areas at different loading speeds and exterior temperatures are determined. Using Clausius-Clapeyron formula, it is shown that with simultaneous changes in temperature and strain rate, the stresses of phase transformations are largely due to changes in temperature rather than load rates. The coefficients of Clausius-Clapeyron equation for superelastic Ni55.75Ti44.15 alloy with shape memory, which are consistent with those known in the literature, are determined.

The influence of external temperature and convective heat exchange with an environment on heat transfer inside phase change material embedded brick

In building industry, phase change materials protect wall structures from thermal loads, smoothing peak temperatures and providing a comfortable thermal regime inside the building. The present research is devoted to the study of heat transfer in a building block with paraffin inserts under unsteady external thermal impact using mathematical simulation technique based on the developed in-house computational code. The effects of external air temperature and the heat transfer coefficient between the environment and the building element on the phase change within the block have been analyzed. It has been shown that an increase in the volume of phase change material has a great influence on heat transfer enhancement and allows to support the optimal thermal regime within the building element. Moreover, a rise of considered block size contributes to a reduction of temperature on an indoor surface by almost 20% of the maximum temperature difference.

Analysis of Deformation and Temperature Characteristics of High-Speed Railway Roadbed in Seasonal Frozen Regions

We have systematically studied the spatial and temporal variation characteristics of deformation and ground temperature based on measuring the values of corresponding data in the Harbin-Dalian high-speed railway roadbed. The regularity and non-uniformity of roadbed deformation distribution were analyzed based on the relationships between its values and structure type, development of freezing depth, roadbed filling, and transverse position. We also compared the difference of freezing conditions at different locations and heat absorption of the roadbed; then we analyzed the differences of freezing depth in four selected roadbed sections and the characteristics of average ground temperature along the vertical direction in the coldest and hottest months. Based on the above analyses, the source of the spatial and temporal characteristics of roadbed deformation, influencing factors, and the potential hazards of transverse thermal difference to roadbed stability have been discussed. The results showed that the distribution of roadbed deformation in seasonal frozen regions had certain regularity, non-uniformity, and randomness. Roadbed freezing processes of roadbed at different transverse locations in different regions were similar. The differences of transverse thermal regime were widespread, and the influence of external temperature on the west shoulder was most obvious. The coldest and warmest month temperatures at a certain depth followed a spindle-shaped trend. Both the increase of latitude and height of roadbed may affect the difference of transverse ground temperatures.

Influence of Hydrophobic Agent on Rheological Behavior of Historical Plaster. Part 2: External Temperature

In a previous study, we presented new method measurement rheological properties of hydrophobized plaster in dependence of hardening time. Influence of external temperature on pozzolana plaster is analyzed in this paper, especially plasticity and workability of paste. Main aim of rheological test is determination of flow curves, obtained by applying a succession of constant strain rates for short times at the temperature 10°C and 30°C. Base on the performed experiments, it can be concluded that the temperature have very significant influence on rheological properties of plasters. With an increase in temperature, the application time of the mixture is shorter, from hour to minutes. A comparative measurement with pure lime plaster was done as well.

Effect of Delaying Addition of Heat Stimulated Superplasticizer on Fresh Properties of Mortar

To assure the quality and required workability of mortar or concrete, various types of superplasticizers are used. There are many factors affecting the performance of superplasticizers explicitly, type and dosage of the superplasticizers, type of cement, temperature and mixing procedure, as well as the addition times of the superplasticizers. Some researchers investigated the effect of delaying the addition time of superplasticizer to mortar or concrete, but there is not enough data about the effect of external temperature on performance of superplasticizers and consequent influences on fresh properties of mortar or concrete. In this research the effect of delaying the addition time of superplasticizers and influence of external temperature, namely, heat stimulation of superplasticizers, on fluidity, fresh density and air content of fresh cement mortar was investigated. Two types of Precast and Ready-Mix of Polycarboxylic acid-based ether superplasticizers with Ordinary Portland Cement was used. Delaying the addition time of superplasticizers enhanced the fluidity, slightly decreased the fresh density and increased the air content of mortar in comparison with simultaneous addition time with both heated and non-heated Superplasticizers.

A Wide-Range Displacement Sensor Based on Plastic Fiber Macro-Bend Coupling

This paper proposes the strategy of fabricating an all fiber wide-range displacement sensor based on the macro-bend coupling effect which causes power transmission between two twisted bending plastic optical fibers (POF), where the coupling power changes with the bending radius of the fibers. For the sensor, a structure of two twisted plastic fibers is designed with the experimental platform that we constructed. The influence of external temperature and displacement speed shifts are reported. The displacement sensor performance is the sensor test at different temperatures and speeds. The sensor was found to be satisfactory at both room temperature and 70 °C when the displacement is up to 140 mm. The output power is approximately linear to a displacement of 110 mm–140 mm under room temperature and 2 mm/s speed at 19.805 nW/mm sensitivity and 0.12 mm resolution. The simple structure of the sensor makes it reliable for other applications and further utilizations, promising a bright future.

The Resistance Relaxation Effect of Conductive Rubber Composite

The application prospect of conductive rubber composite is introduced. The mechanism of resistance relaxation of conductive rubber composite was expounded. Several representative mathematical models of the resistance relaxation effect of conductive rubber composite were introduced. The influence of external temperature, heat treatment temperature, the amount of conductive filler, the type and the size of stress, nanomodified materials and dispersing additives on the resistance relaxation effect of the conductive rubber composite were discussed respectively. Finally, a brief description of the application status of conductive rubber composite and its summary and outlook were made.

The Research on Analysis and Control of Cracks of Masonry Structure

Through the cracks because of influence of external temperature, and mixed thermal stress in the approximate calculation of the proposed measures to prevent the multi-storey top floor vertical wall cracks, to be prevented in the design, engineering examples by design better buildings products.

Thermal behavior in different roof coverings on classrooms

2 . Three classrooms were covered with asphaltic bitumen of three different colors (red tile, matte white and ebony black) the last one was covered with typical clay of the region. Two temperature sensors were installed in each classroom. The first one was fixed outside of the calssrooom at 0.40 m above the roof surface and the second one was installed 0.15 m below the ceiling. The temperature data were stored over ten minutes with a set of remote terminal units which form a wireless sensor network. The results showed significant differences in temperature between the four classrooms with a grade of significance of 0.05, and it showed that the color of the roof deck significantly influences the thermal behavior inside the classrooms. The influence of external temperature over the internal temperature was quantified with the r-Person coefficient, which was found at a mean value of 0.98.

GROUND STATE LIFETIME OF STRONG-COUPLING MAGNETOPOLARON IN AN ASYMMETRIC QUANTUM DOT

The ground state lifetime of a magnetopolaron was investigated with electron–LO-phonon strong coupling in an asymmetric quantum dot using the linear combination operator and unitary transformation methods. Quantum transition, which cause changes of the magnetopolaron lifetime, occurs in the quantum system due to electron–phonon interaction and the influence of external temperature, that is, the magnetopolaron leaps from the ground state to the first excited state after absorbing a LO-phonon. The expressions of the ground state lifetime of the magnetopolaron as a function of the ground state energy, the transverse and longitudinal confinement lengths of quantum dot, the electron–phonon coupling strength, the cyclotron vibration frequency and the external temperature were obtained. Numerical calculations have been performed and the results show that the ground state lifetime of the magnetopolaron increases with increasing the ground state energy and the cyclotron vibration frequency, and decreases with increasing the transverse and longitudinal confinement lengths of the quantum dot, the coupling strength and the external temperature.

Influence of Regional Climate on Basal Metabolism

In a country long and narrow compared with its area such as Japan, there is a tolerable provincial difference in external temperature between the Northern region and the Southern region. It must therefore be natural to consider that external temperature difference has effects on the basal metabolism (BM) of the population.Though we have already reported that the seasonal BM has a close relation with external temperature, there still remains room to doubt whether a completely identical relation such as this can exist in regional climate difference, because in cold and warm regions clothing and heating, i. e., artificial climate conditions differ; besides this, the individual difference of exposure time to such artificial temperature must also be considered.Taking winter for example, heating conditions are satisfactory in the Northern region and people spend more time of their every-day life indoors. While in the Southern region though the external temperature is not exceedingly low, room temperature is almost equivalent to external temperature as heating conditions are unsatisfactory and people are under the influence of external temperature all day long.From this point of view, we have carried out BM observations on personnel of the Self Defence Forces since 1950, a total of 1453 persons in number, selected through out the country mainly in summer and winter. These men were selected as subjects for the reason that they are scattered all over the country and also because their labor and other living conditions are identical.Results of BM measurements are presented in the next table and figures: Table shows each value; Figure 1 localizations of subjects; Table 2 relation of external temperature and BM of entire subjects; Table 3 relation of external temperature and BM of infantry corps only, dots in the figures indicate average BM values of each region.From these data the following tendency is evident:1. BM values are in reverse proportion to external temperature.2. BM has a tendency to increase abruptly with temperature-decrease till 10°C attained. At temperatures above an increase of approximately 5% for each 10° is observed with temperature-decrease.At temperatures lower than 10°C this inclination declines. There is a 1-2% BM increase with a 10° decrease in temperature.This trend mentioned above is completely reverse to naked-cold exposure in an air conditioned room. This may he attributed to protection from cold by means of heating and clothing and spending more time of their everyday life indoors in Northern region.Observing the entire temperature range there is an apprx. 2.5% increase in BM values for every 10°C decrease in temperature, this coefficient being almost in consistence with seasonal variation.

諸種薬物の家兎体温に及ぼす影響 (第4報)

Influence of external temperature on the body temperature of a rabbit fixed on its back was examined. The decrease of atmospheric temperature to 0°C failed to effect any marked decrease of body temperature in unfixed rabbits. The rabbits were fixed on its back at this temperature, and when the body temperature has decreased considerably, pyrogen and a substance which normally effects lowering of body temperature in rabbits were administered. As a result, it was found that the body temperature failed to rise by the administration of pyrogen in minimum pyrogenous amount, but the lowering of body temperature was also found to be small.

The Influence of External Temperature on the Hive Temperatures During the Summer

The purpose of this experiment was to study the variations in temperature occurring within different regions of a hive during summer and to explain if possible to what the variation is due.