KTU Open Journal Systems (Kaunas University of technology)
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Forest Fire Recognition and Prediction Based on Fully Convolutional Network and Rothermel Model
No full textThis paper establish a combined fire recognition and prediction model to study the spread of forest fires in response to the frequent occurrence of forest hill fires and its difficult recognition and prediction pain point. Based on the traditional recognition neural network, this paper innovatively establishes Fully Convolutional Network (FCN) to improve the fire recognition accuracy. The Rothermel model is introduced for fire spread prediction of the Palisades Mountain Fire in Los Angeles, and it is found that the accuracy of the Rothermel model is as high as 87% and the stability is about 70.9%. Referring to the excellent model performance of the Rothermel model, this paper establishes a combined model for identification and prediction with the combination of FCN and Rothermel in order to improve the accuracy of fire identification and prediction, and provide double accuracy to ensure the reliability of the study. Based on the simulation of forest fires in a simulated wildland environment, the fire spreading stages are segmented into 4 parts, fire recognition is performed by FCN network, and Rothermel fire prediction is performed based on the recognition results. It is found that the combined model effectively reduces the errors of individual models, complements the advantages of individual models, and improves the fire identification and prediction accuracy. At last, this paper suggests a combination with the field of drones for smart fire prevention and reference
The Impact of Internationalization on Firm Performance of High-Tech Companies in Poland in the Context of Covid-19
No full textThis study aims to examine the impact of the internationalization of high-tech companies on their firm performance against the COVID-19 crisis in Poland. The research covers the period of 2018-2020 (3 years) and encompasses 591 firm-year observations, with 192 high-tech firm-year observations (64 companies) and 399 non-high-tech firm-year observations (133 companies). To find out the differences between subsamples, the U Mann-Whitney test was implemented. At the same time, correlation and regression analysis were exploited to highlight the impact of the crisis, internationalization, and the company\u27s status on firm performance. Our research shows that, in Poland, the COVID-19 crisis had a generally weak impact on internationalization and firm performance. However, in a high-tech subsample, we find an increase in profitability during the COVID-19 crisis. Both subsamples show an increase in financial liquidity ratios during the COVID-19 crisis. The study also demonstrated that internationalization has a weak impact on firm performance. At the same time, the company\u27s status (high-tech) positively impacts internationalization, financial liquidity, and company growth
The Triple Interaction: Environmental Corporate Social Responsibility, Environmental Regulation, and Environmental Commitment in Shaping Environmental Performance in China
No full textGrowing demands for environmental corporate social responsibility (ECSR) from firms have been brought about by the rise of environmental sustainability and green business management. An increasing number of academics have focused on the impact of ECSR on firm environmental performance (FEP). However, scant attention has been given to environmental commitment (EC) as a mediator and environmental regulation (ER) as a moderator. To bridge this gap, this study checks the impact of ECSR on FEP through EC. Moreover, the relationship between ECSR and FEP was investigated in the presence of ER. The data has been collected from manufacturing companies that operate in China using convenience sampling to disburse questionnaires among respondents. We received 354 valid responses to 560 questionnaires, and 106 responses were incomplete, making an impressive response rate of 76.95 %. The findings of this study reveal that ECSR significantly enhances FEP, indicating that companies engaging in responsible environmental practices can improve their environmental outcomes. It also confirms that EC serves as a mediator in the relationship between ECSR and FEP, suggesting that a firm\u27s dedication to environmental sustainability strengthens the positive impact of ECSR on FEP. Additionally, the study finds that ER negatively moderates the link between ECSR and FEP. This means that stricter environmental regulations might dampen the positive effects of ECSR on a FEP. This study also has limitations and future directions, persuading the researcher to develop new avenues
Structure of Bifunctional Planar Micro Supercapacitor and Electrochromic by Screen Printing Technology
No full textA planar micro-supercapacitor(MSC) has characteristics between battery and capacitor. MSC sandwich structure’s limitation includes short circuit with two electrodes, electrodes should be loaded with as many active materials as possible to improve the energy storage capacity of the device, both of which will increase the ion transfer impedance, resulting in low power density. On the other hand, the sandwich structure is difficult to integrate into micro electronic devices. In recent years, the cross-fertilization of electrochromic technology with other fields has given rise to a variety of emerging smart devices and technologies by combining with supercapacitors, smart energy storage devices and smart windows. This paper focuses on hybrid of MSC and electrochromic device structure to verify bifunctional device structure by asymmetric interdigital electrodes. They require same hydrogel and electrode layer to enhance their performance, which are pursued with reduction in width, size, power consumption and price in the field of portable, etc. The material of Ag/Carbon/PVA/KCL/PEDOT:PSS(ACPKP)for new structure will be printed as to ensure device’s energy-storage and display. As expected, the micro-supercapacitor based on PET film can deliver areal capacitance up to 6.5 mF/cm2. Even if, micro-supercapacitor undergoes continuous 800 cycles, the performance of device can still remain nearly 79.4%. With printing technology, low cost, large area and green products demonstrate its great application in next-generation flexible electronics
Study on Wear Characteristics of Coal Drain Chute for Open Pit Mine
No full textWith the advancement of social science and technology and the escalating demand for resources, the utilization rate and load of mechanical equipment in diverse industries have become increasingly prominent. Mechanical malfunctions occur frequently, especially in material transportation, causing substantial economic losses. Mechanical wear has emerged as the principal cause of mechanical equipment failure; hence, studying the wear of particles and transportation machinery is of paramount importance. This paper utilizes the discrete element method and numerical simulation approach to investigate the influence of mechanical structure alterations on the wear of discharge chutes in coal conveyor systems. The results reveal that in terms of speed, reducing the conveyor belt speed has negligible effects on the falling trajectory and distribution characteristics of the materials but reduces the frequency of contact between the materials and the chute surface, thereby diminishing the tangential force exerted by the materials on the chute. The tangential cumulative force plays a crucial role in the wear of the chute by granular particles and can effectively alleviate the wear of the chute. With respect to the inclination angle of the conveyor belt, when increasing the angle clockwise, the influence on the falling trajectory and distribution characteristics is relatively minor, and the falling speed of the materials will accelerate. Nevertheless, the wear of the chute will decrease as the inclination angle increases. When increasing the inclination angle counterclockwise, the falling trajectory and distribution characteristics are significantly affected, and the materials will tend to concentrate, and the falling speed will decelerate, resulting in a substantial reduction in chute wear. These discoveries provide theoretical underpinnings for reducing equipment wear and optimizing coal transportation equipment
Fabrication of High Chromium Cast Iron/Hadfield Steel Composite Materials by the Hot Rolling Process
No full textBimetal composite blanks were successfully prepared from high chromium cast iron (HCCI) and Hadfield steel by the hot-rolling process. The macrostructure and microstructure of the composite were investigated. After hot-rolling formation, the hard HCCI layers were fractured and embedded in ductile Hadfield steel, forming a three-dimensional composite structure. The two metals were fused and no defects such as interface cracks or unbonded areas were found. A metallurgical bonding between Hadfield steel and HCCI was revealed. The kernel average misorientation (KAM) value of the Hadfield steel layer was low, while the HCCI layer showed a larger green area. It indicated that the HCCI layer had high strain energy and high dislocation density. The bonding process of two metals includes three stages: physical contact, physico-chemical bonding and mutual diffusion
Removal of Heavy Metal Chromium in Groundwater by Sulfidated and Carboxymethyl Cellulose Modified Nanoscale Zero-valent Iron
No full textIn this study, nanoscale zero-valent iron (nZVI) was investigated for its effectiveness in removing chromium, a major groundwater contaminant. To enhance nZVI’s removal performance, sulfurization and sodium carboxymethyl cellulose (CMC) modifications were applied. Three preparation methods were used to create modified nZVI materials with distinct structures, and their removal efficiencies were compared. Results showed that the nZVI modified via surface corrosion achieved the highest removal efficiency. Furthermore, the study explored the effects of various factors on the removal efficiency, including the molar ratio of sulfurizing agent to iron, initial pH, reaction temperature, the dosage of modified nZVI, and the initial concentration of hexavalent chromium. The results showed that the highest chromium removal rate (96.97 %) was achieved when the molar ratio of sulfurizing agent to iron was 0.4, the initial pH was 3, the reaction temperature was 25 ℃, the dosage of modified nZVI was 52 mg/L, and the initial hexavalent chromium concentration was 12 mg/L. After three cycles of reuse, the modified nZVI material still maintained a removal rate of 94.73 %. Additionally, the presence of various ions in wastewater was found to influence the removal efficiency. The effect of anions was minimal and could be neglected, while the presence of cations, particularly Mg2+, had a significant impact on removal performance. Under conditions simulating multi-ion groundwater, the modified nZVI material demonstrated a removal rate of up to 90.25 % for hexavalent chromium, highlighting its potential for practical applications
A Study on the Corrosion Inhibition Performance of Various Starches for Q235A Steel
No full textEight different varieties of starch were chosen to replace the corrosion inhibitors in order to assess the corrosion resistance and rate of deterioration of Q235A steel using an electrochemical test and the weightlessness method. The metallographic microscope was used to examine the corrosion product surface on the steel plate. The results of the weightless method show that the corrosion rate of 300 mg/L of starch was higher than the concentration of 500 mg/L. As the concentration of H2SO4 was 0.5 mol/L, the corrosion rate of 300 mg/L of cassava starch, mung bean starch, and wheat starch solution was higher than the others, which were 72.92 %, 72.89 %, and 72.02 %.The results of the electrochemical test show that the corrosion resistance of 300 mg/L pea starch and cassava starch solution were better in the condition of 0.5 mol/L H2SO4, whose self-corrosion currents were 34 μA∙cm-2 and 26 μA∙cm-2. Their solution resistance RS were 1.739 Ω∙cm-2 and 1.801 Ω∙cm-2, respectively. In conclusion, the effect of 300 mg/L of tapioca starch and pea starch was better in 0.5 mol/L H2SO4 solution
Investigation of CO2 Capture Ability in Amino Acid Ionic Liquid-Functionalized Metal-organic Frameworks
No full textDue to their significant porosity and adjustable structures, metal-organic frameworks (MOFs) exhibit great promise for CO2 sequestration. This investigation focuses on the augmentation of CO2 capture capabilities in MOF-177 through impregnation with two amino acid-derived ionic liquids (AAILs), [BMIm]Glu and [BMIm]Asn. The AAIL@MOF-177 composites obtained were analyzed, confirming successful AAIL loading without significant disruption of the MOF structure. Remarkably, the composites demonstrated a marked enhancement in CO2 uptake and preference for CO2/N2 and CO2/CH4 relative to the pristine MOF-177, especially under low-pressure conditions typical of post-combustion flue gas. The optimal AAIL loading was determined to be 30 wt.%. Under conditions of 0.2 bar and 25 ℃, [BMIm]Asn-30@MOF-177 achieved a CO2 uptake of 0.48 mmol/g, a 3.5-fold increase over pristine MOF-177. Furthermore, [BMIm]Asn-30@MOF-177 demonstrated superior CO2/N2 and CO2/CH4 selectivities of 14.2 and 11.9, respectively, under 0.2 bar and 35 ℃. This enhanced performance arises from the robust chemical affinity between CO2 and the amino groups in the AAIL anions, especially the two amino groups in [BMIm]Asn. The composites also showed excellent reusability over multiple adsorption-desorption cycles. These findings demonstrate the promising potential of AAIL-functionalized MOFs for efficient CO2 capture
Thermal-ultraviolet-humidness Coupling Aging Mechanisms of SBS Modified Asphalt Considering Actual Climatic Conditions
No full textStyrene-butadiene-styrene (SBS) modified asphalt is susceptible to aging due to the combined effects of environmental factors, including temperature, ultraviolet radiation, and humidness. However, existing studies primarily focus on single aging conditions, neglecting the synergistic effects of thermal, ultraviolet, and humidness factors on the aging properties of asphalt. Given the vast territory and significant environmental variations in China, this study selects five representative cities as subjects for research. The research utilizes the Rolling Thin Film Oven Test (RTFOT) in combination with a coupled aging chamber to simulate the aging process. This study analyzes the effects of varying temperature, duration of ultraviolet radiation exposure, and humidness conditions on the macroscopic performance of asphalt, specifically through ductility and softening point tests. Additionally, it elucidates the aging mechanisms of SBS modified asphalt using Fourier Transform Infrared Spectroscopy (FTIR) and fluorescence microscopy (FM). The results indicate that high humidness and temperature environments significantly accelerate the aging of asphalt, with temperature playing a dominant role in hastening the aging process of SBS-modified asphalt. Microscopic analysis reveals that the primary mechanisms of SBS degradation and oxidation reactions occur during the aging process. Notably, the change in the functional group index of SBS-modified asphalt under high humidness and temperature conditions is most pronounced. The decomposition of the SBS network crosslinking structure is most severe, resulting in the weakest fluorescence intensity