Papers by Keyword: Temperature

Abstract: Cold forming is characterized by high dimensional and shape accuracy as well as energy and cost efficiency in the series production of highly stressed components. Cold forming is characterized by high tribological loads. Complex lubrication systems are necessary to ensure fault-free production despite the high tribological loads. In the course of increasing demands on environmental compatibility, the disadvantageous zinc-phosphate-based lubricant systems have been replaced by more environmentally friendly single-layer lubricant systems. However, their functionality is strongly dependent on temperature, so that exact knowledge of the prevailing temperatures in the forming zone is necessary for optimum design of the lubricants [1]. Due to the high tribological stress, established measuring methods based on thermocouples can only approach the forming zone up to 10 mm. Previous works of the authors have shown that sensory lubricants based on thermochromic indicators are in principle capable of measuring temperatures directly in the forming zone [2,3]. Their functionality is based on the irreversible color change as a function of temperature [4]. The aim of this study is to develop a standardized test methodology for calibrating the sensory lubricants, which enables an exact correlation between temperature and color value. In addition, suitable indicators are to be identified and their influence on the tribological system analyzed. The test methodology developed uses inductive heating to heat the samples coated with the sensory lubricant to as high as 500 °C within 1 s. The temperature of the surface is determined by the temperature of the lubricant. By determining the surface temperatures reached as well as the color values under diffuse illumination in an integrating sphere, defined temperature ranges can be assigned to the color values of the indicators. With three indicators, which were identified as suitable, it was possible to detect temperatures in the contact zone of a full forward extrusion process and in the contact zone of the sliding compression test that reflect the simulated temperatures. In addition, the sliding compression test showed that the indicators have no influence on the tribological system up to an indicator concentration of 4 %.

Abstract: A thermoelectric generator can produce electrical energy using the extra heat from many sources, such as a Liquefied Petroleum Gas (LPG) cooking stove. This study aimed to examine the impact of varying LPG mass flow rates on the temperatures and power output of a thermoelectric generator (TEG). The LPG stove was altered by incorporating a hot side heat exchanger to enclose the burner, enabling the integration of four thermoelectric generators coupled in a series configuration. The temperature of the TEG hot and cold sides was measured using thermocouples and recorded using a data logger controlled by an Arduino. It is evident from the result that increased LPG mass flow rates cause the heat exchanger on the stove burner to heat up. There was a link between the temperature trend line of the TEG and the current, voltage, and power. The gas mass flow rates of 0.26 kg/h, 0.18 kg/h, and 0.14 kg/h correspond to power outputs of 3.09 W, 1.53 W, and 0.1 W, respectively. This study has demonstrated that installing a thermoelectric module on the LPG stove can serve as an alternate method to harvest the energy from the waste heat.

Abstract: Traditional control charts often struggle to simultaneously detect both small and large shifts in process parameters. This study proposes the AEWMA-Max method, an improved variant of the Adaptive Exponentially Weighted Moving Average Max (AEWMAM) chart, to address this challenge in the context of monitoring temperature fluctuations in vannamei shrimp ponds. The research employs a data set containing 26 out-of-control and 64 in-control temperature measurements. AEWMA-Max utilizes a dynamically adjusted smoothing parameter (L) to achieve optimum sensitivity for both subtle and significant deviations from the desired temperature range. Through extensive simulations and comparisons with existing control charts, L = 2.642 was identified as the most effective value for this specific application. The amount of out-of-control data on the control chart is the better metric for determining the best charts used in monitoring the process. Based on the monitoring results, the proposed AEWMA-Max method demonstrably outperforms traditional charts in detecting both small and large temperature shifts, offering enhanced process control and potentially improved shrimp survival rates.

Abstract: The quality of water stands particularly in the context of green globalization. Ensuring the safety of drinking water necessitates of water quality monitoring in real-time. The present study introduces a cost-effective solution for water quality monitoring in real-time through the advance developing of a cost less system. The system integrates multiple sensors capable of measuring both physical and chemical parameters of water, including temperature, pH, turbidity, and total dissolved solids. The data collected from these sensors are processed by a core controller, with the Arduino model identified as a suitable candidate. This system offers an affordable and efficient means of continuous water quality monitoring, thereby contributing to the provision of clean and safest drinking water resources in era of green globalization.

Abstract: Temperature and steel fiber content have a great influence on the mechanical behavior of concrete, so it is urgent to study the mechanical properties of concrete at different temperatures and steel fiber content. The effects of temperature and steel fiber content on the mechanical properties of concrete are studied in this paper. Based on the uniaxial compression testing machine, the uniaxial compression tests of concrete under different temperatures (150°C, 300°C, 450°C) and different steel fiber content (0%, 1%, 2%, 3%) are carried out. With the increase of temperature, the compressive strength of concrete first increases and then decreases, which indicates that there is a critical temperature for the influence of temperature on the compressive strength of concrete. In addition, the addition of steel fiber content significantly improves the compressive strength of concrete. In addition, temperature and steel fiber content significantly affect the peak strain of concrete. Based on the SEM test results, the temperature effect of concrete was investigated from the microscopic perspective.

Abstract: The development of multiphase bainitic/martensitic steel aims to enhance the mechanical properties and corrosion resistance compared to traditional pearlitic steel. However, the impact of elevated temperatures on the corrosion resistance behavior of these materials cannot be overlooked. This study investigates the corrosion resistance behavior of multiphase bainitic/martensitic steel and pearlitic steel at varying temperatures. Electrochemical tests using Electrochemical Impedance Spectroscopy (EIS) and Linear Polarization (LP) in a 3.5 wt.% NaCl solution demonstrate a consistent trend: acicular bainitic steel exhibits superior corrosion resistance compared to granular bainitic steel and pearlitic steel at both room temperature and elevated temperatures. Further characterization using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) reveals that the formation of oxide layers significantly contributes to the enhanced corrosion resistance observed in these materials.

Abstract: The aim of this study is to investigate the influence of temperature on the shear strength and elastic stiffness of sand under triaxial compression (TC) test. Air-dried Ottawa sand specimens were prepared to avoid pore pressure induced during shearing. Ottawa sand, widely used in geotechnical engineering research, was selected for these TC tests. The sample was first drained and then heated to different target temperatures (i.e., 30, 45 and 60°C), which were maintained constant during the tests. After heating, the sample was sheared under a constant cell pressure and temperature. Small strain-amplitude cyclic loading was applied successively at different shear stress levels to investigate the elastic Young’s modulus (E_eq) behaviour. The results revealed that the peak shear strength increased with increasing temperature. For E_eq values, a clear relationship with temperature was observed, indicating that elastic stiffness of Ottawa sand also increased with temperature. These findings are significant as they demonstrate that temperature variations can markedly affect the mechanical behaviour of sand, which is important for understanding and predicting the performance of geotechnical structures subjected to thermal effects. Moreover, a sudden drop of stress can be observed as a phenomenon commonly observed in round particle shapes.

Abstract: Coconut husk materials have become emerging candidates for the industry of furniture and housing due to their properties and abundance in tropical regions. This study explores using coconut chips, a sustainable and biodegradable resource as an alternative material to produce eco-friendly fibrous boards. The binderless chipboards were fabricated from coconut chips using compression molding at different pressing temperatures and times. The binderless chipboards’ thickness, density, and flexural properties were investigated. Results indicate that higher pressing temperatures and longer pressing times result in reduced thickness, lower density, and improved modulus of rupture (MOR) and modulus of elasticity (MOE). Based on the findings of this study, it is suggested that binderless chipboards produced under optimized conditions could offer a viable alternative to traditional wood based particleboards.

Abstract: Iron oxide was produced from lathe waste using green tea leaf extracts. Green tea leaves contain catechins, has been produced as a possible reducing, precipitating, stabilizing, and capping agent. Another advantage of applying green tea leaves to synthesize iron oxide is reducing toxicity. Various temperatures of synthesis utilizing the precipitation method proved successful in the formation of hematite. X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscope (SEM) were used to characterize the synthesis product. According to the XRD results, the magnetite transition phase was obtained after precipitation, while hematite formed after calcination. The crystallite sizes were 50.5 nm, 45.4 nm, and 39 nm, respectively. According to FTIR identification, the iron oxide was generated before and after calcination in the presence of a specific Fe-O group at the wavenumbers 553 cm^-1 and 451 cm^-1. The SEM results revealed that the particle size ranges from 4.61 nm – 20.74 nm, and the shape was not uniform, and aggregation.

Abstract: The present study aims to numerically investigate the effective thermal conductivity values (ETCs), the thermal transmittance coefficient (U-value), heat and moisture flux of the multi-layered insulation materials in regard to the influence of temperature and humidity variations for building envelope applications. The research model is performed as an exterior wall structure including 3 layers in order oriented stranded fiberboard (OSB), cellulose fiberboard (CFB), and oriented stranded fiberboard (OSB) in which the cellulose fiberboard plays as a core layer. For the stationary study, results showed that ETCs increased slightly with the increase of temperature (5-20 °C) and the increase of humidity levels (33-90%). Besides, the thermal transmission recorded a significant decrease when the thickness of CFB changed from 50 to 200 mm. Accordingly, the reduction of U-value is very close to the reference value (0.24 W/(m²·K)) demonstrating that the defined model could be potential for practical study. Interestingly, the dynamic study highlighted a larger difference in the ETCs in summer than in winter due to the great influence of moisture migration in the value and phase change of the heat flux fluctuation. As a result, the simulation indicated the general trend of the ETCs was always associated with the variations of ambient temperature and relative humidity. Therefore, the proposed model and its numerical works could be considered as the prominent solution for practical use in building envelope applications.