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2022

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Articles 6661 - 6690 of 9373

Full-Text Articles in Engineering

Mechanical Properties And Acoustic Emission Characteristics Of Sandstone Under Natural And Saturated Conditions, Zhang Yin, Li Zhe, Song Shikang, Zhao Yi, Li Hao Feb 2022

Mechanical Properties And Acoustic Emission Characteristics Of Sandstone Under Natural And Saturated Conditions, Zhang Yin, Li Zhe, Song Shikang, Zhao Yi, Li Hao

Coal Geology & Exploration

In order to study the mechanical properties and acoustic emission (AE) characteristics of sandstone with different grain sizes in the process of damage and failure under saturated and natural conditions, we carried out uniaxial compression tests and AE tests on three kinds of sandstone under saturated and natural conditions to study the mechanical properties and AE characteristics under the uniaxial stress state. The test results show that the average compressive strength of coarse-grained sandstone, medium-grained sandstone, and fine-grained sandstone are 54.23 MPa, 53.56 MPa, 59.46 MPa respectively under natural conditions, and 35.62 MPa, 31.79 MPa and 29.10 MPa under saturated …

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The Reflected Radio Wave Method For Detecting Coal Seam Faults In Mining Face, Gu Huanqi, Wu Rongxin, Shen Guoqing, Hu Ze Feb 2022

The Reflected Radio Wave Method For Detecting Coal Seam Faults In Mining Face, Gu Huanqi, Wu Rongxin, Shen Guoqing, Hu Ze

Coal Geology & Exploration

Mine radio wave exploration can be used for coal seam geological structure exploration. With its advantages of portability and good effect, it has become a conventional and necessary means for coal seam geological structure exploration. At present, the energy attenuation of radio wave signal in coal seam is fast, and the transmission radio wave detection of working face is restricted in large width coal seam. On this basis, the radio wave reflection exploration method of coal seam working face is proposed. Firstly, the electric model of two-dimensional coal measure strata is constructed by numerical simulation to analyze the field strength …

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Down-Hole Ø550 Mm Super Large Diameter Coal Seam Borehole Drilling Technology And Equipment And Its Engineering Application, Sun Yongxin Feb 2022

Down-Hole Ø550 Mm Super Large Diameter Coal Seam Borehole Drilling Technology And Equipment And Its Engineering Application, Sun Yongxin

Coal Geology & Exploration

For the prpose of improving the gas control efficiency and reduce the cost in the goaf of “U” ventilation face, the ø550 mm super-large diameter borehole was used to replace the cross-heading buried pipe for gas drainage in goaf. According to the characteristics of super-large diameter borehole and the technical problems existed in construction, a ZDY15000LP super-large diameter spiral drilling rig with maximum torque 15000 N·m, maximum penetration 700 kN, and maximum stroke 1.3 m has been developed, which adopted the two-body layout of main engine and pump station, and the innovative design of key parts such as main engine, …

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Acoustic Emission Characteristics And Fracture Response Behavior Of Hard Rock-Like Material Under Influence Of Loading Rate, Zhang Zekun, Song Zhanping, Cheng Yun, Huo Runke, Song Wanxue, Wang Kuisheng, Wang Tong, Yang Tengtian, Liu Wei Feb 2022

Acoustic Emission Characteristics And Fracture Response Behavior Of Hard Rock-Like Material Under Influence Of Loading Rate, Zhang Zekun, Song Zhanping, Cheng Yun, Huo Runke, Song Wanxue, Wang Kuisheng, Wang Tong, Yang Tengtian, Liu Wei

Coal Geology & Exploration

For the purpose of clarifying the correlation between Acoustic Emission(AE) and rupture response characteristics and loading rate in the failure and instability of hard rocks, uniaxial compression tests and acoustic emission tests were conducted on hard rock-like material samples at different loading rates to analyze the characteristics of mechanical parameters, AE phenomena and rupture response characteristics of hard rock-like material, and to obtain the early warning information of the rock failure based on the information on AE parameters. The results show that the peak strength, elastic modulus and peak strain of hard rock-like material have the loading rate effect. The …

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Childminding Professionalism And Professionalisation In Ireland: A Different Story, Miriam O'Regan, Ann Marie Halpenny, Noirin Hayes Feb 2022

Childminding Professionalism And Professionalisation In Ireland: A Different Story, Miriam O'Regan, Ann Marie Halpenny, Noirin Hayes

Articles

This research focussed on documenting the praxis and paedagogy of paid, professional childminding (family childcare/day care) in Ireland. It explored professionalism and professionalisation among childminders in the context of the evolving understanding of professionalism in Early Childhood Education and Care (ECEC) nationally and internationally. The research was conducted within the framework of Ecocultural Theory (ECT) on the eve of mandatory regulation of childminding against the backdrop of Irish ECEC policy. A mixed method approach was adopted, using the Ecocultural Family Interview for Childminders (EFICh), including participants’ photographs, case study surveys, researcher field notes and holistic ratings. We present findings related …

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Effects Of The Agglomerated Fracturing Fluid On The Transportation Of Pulverized Coal And Its Mechanism, Song Jinxing, Shi Junke, Liu Jianzhuang Feb 2022

Effects Of The Agglomerated Fracturing Fluid On The Transportation Of Pulverized Coal And Its Mechanism, Song Jinxing, Shi Junke, Liu Jianzhuang

Coal Geology & Exploration

During the drainage process, the pulverized coal moves with the carrier fluid in supporting fractures, resulting in the blockage of the fractures and then a decrease in the permeability of the coal reservoir and the conductivity of the supporting fractures. For the purpose of exploring the effects of the properties of the agglomerated fracturing fluid on the transportation of pulverized coal and its mechanism, the coal samples from Urumqi Hedong Mining Area in southern Junggar Basin coalfield are selected as the research object, with distilled water, active water fracturing fluid(1.5%KCl), and agglomeration fracturing fluid(1.5%KCl+0.05%AN) as the carrier fluids. Through the …

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Thermosensitive Polymers And Thermo-Responsive Liposomal Drug Delivery Systems, Waad H. Abuwatfa, Nahid S. Awad, William G. Pitt, Ghaleb A. Husseini Feb 2022

Thermosensitive Polymers And Thermo-Responsive Liposomal Drug Delivery Systems, Waad H. Abuwatfa, Nahid S. Awad, William G. Pitt, Ghaleb A. Husseini

Faculty Publications

Temperature excursions within a biological milieu can be effectively used to induce drug release from thermosensitive drug-encapsulating nanoparticles. Oncological hyperthermia is of particular interest, as it is proven to synergistically act to arrest tumor growth when combined with optimally-designed smart drug delivery systems (DDSs). Thermoresponsive DDSs aid in making the drugs more bioavailable, enhance the therapeutic index and pharmacokinetic trends, and provide the spatial placement and temporal delivery of the drug into localized anatomical sites. This paper reviews the fundamentals of thermosensitive polymers, with a particular focus on thermoresponsive liposomal-based drug delivery systems.

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Potential Of Oil-Rich Coal Resources In Shaanxi Province And Its New Development Suggestion, Ma Li, Wang Shuangming, Duan Zhonghui, Yang Fu, Fu Deliang, He Dan, Zhang Liwei Feb 2022

Potential Of Oil-Rich Coal Resources In Shaanxi Province And Its New Development Suggestion, Ma Li, Wang Shuangming, Duan Zhonghui, Yang Fu, Fu Deliang, He Dan, Zhang Liwei

Coal Geology & Exploration

Under the requirement of carbon peak and carbon neutral targets, the low carbon development and utilization of coal resources in Shaanxi Province is imperative. The law of tar yield from high to low in each coalfield of Shaanxi Province was revealed based on more than 5 000 sets of coal quality data: northern Shaanxi Triassic Coalfield, northern Shaanxi Jurassic Coalfield, Shanbei carboniferous Permian Coalfield, Huanglong Jurassic Coalfield, Weibei carboniferous Permian Coalfield. And three types of oil-rich coal were classified: oil-rich coal type, oil-rich coal-high oil-coal type, oil-rich coal-oil-coal type. According to the calculation method of coal resources, Shaanxi Province has …

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Research On The Graphitization Potential Of Coal In Sichuan And Chongqing, Li Jing, Wang Lu, Liu Yongwang, Luan Jinhua, Zhang Ruigang, Zhang Sen, Wang Anmin Feb 2022

Research On The Graphitization Potential Of Coal In Sichuan And Chongqing, Li Jing, Wang Lu, Liu Yongwang, Luan Jinhua, Zhang Ruigang, Zhang Sen, Wang Anmin

Coal Geology & Exploration

The graphitization of coal is beneficial to enhancing the strategic guarantee ability of graphite resources and promoting the efficient utilization of coal measures mineral resources and transformation and upgrading of coal enterprises. The development potential of coal-based graphite resources in Sichuan and Chongqing is evaluated in the critical period of energy and mineral reform and transformation. On the basis of the analysis of coal graphitization, the precursors for coal-based carbon materials and coalfield geology, the major coal types, coal quality and characteristics of macerals, Principal Component Analysis(PCA) is applied to explore the development potential of coal-based graphite in Sichuan and …

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Present Situation And Prospects Of Coal-Derived Gas Exploration And Development In Shanxi Province, Gong Jieli, Li Guofu, Li Dehui, Liu Liangliang, Wang Zheng, Xu Yun, Wang Xuchao Feb 2022

Present Situation And Prospects Of Coal-Derived Gas Exploration And Development In Shanxi Province, Gong Jieli, Li Guofu, Li Dehui, Liu Liangliang, Wang Zheng, Xu Yun, Wang Xuchao

Coal Geology & Exploration

Coal-derived gas includes coalbed methane(CBM), shale gas and tight sandstone gas. CBM development is of practical significance to ensure coal mine safety, increase clean energy supply, improve regional energy consumption structure, and promote the clear water and blue sky program, which is more in line with the national strategic requirements of developing green energy, achieving carbon neutrality and peaking carbon dioxide emissions. Shale gas and tight sandstone gas are of great significance to improve China’s energy structure and achieve the goal of carbon neutrality and peaking carbon dioxide emissions. Based on the comprehensive analysis of the beneficial exploration and successful …

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Risk Assessment Of Water Inrush From Coal Seam Floors Based On Multiple Methods, Ren Junhao, Wang Xinyi, Wang Qi, Wang Junzhi, Zhang Bo, Guo Shuitao Feb 2022

Risk Assessment Of Water Inrush From Coal Seam Floors Based On Multiple Methods, Ren Junhao, Wang Xinyi, Wang Qi, Wang Junzhi, Zhang Bo, Guo Shuitao

Coal Geology & Exploration

Five factors including the thickness of the aquifer, the complexity of the fault, the water pressure of the aquifer, the unit water inflow of the aquifer, and mining height of 51 boreholes in No.2, No.10 and No.12 Coal Mines of Pingdingshan Coalfield are selected as the index factors. On the basis of the constant weight calculated by the analytic hierarchy process and grey relational analysis, the variable weights of each index factor are determined by applying the variable weight theory. By using the matter-element extension method, fuzzy variable set theory, catastrophe theory, and fuzzy comprehensive evaluation method, the water inrush …

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Quantification And Mechanism Analysis Of Meso-Damage Of High-Temperature Granite Under Different Cooling Modes, Zhang Sen, Shu Biao, Liang Ming, Lu Wei, Hu Yongpeng, Xue Hui Feb 2022

Quantification And Mechanism Analysis Of Meso-Damage Of High-Temperature Granite Under Different Cooling Modes, Zhang Sen, Shu Biao, Liang Ming, Lu Wei, Hu Yongpeng, Xue Hui

Coal Geology & Exploration

Cooling shock is an effective method to increase the permeability of geothermal reservoir by causing fractures on high temperature rock. For the purpose of quantitatively analyze the damage degree of granite caused by cooling shock at different heating temperatures and explore the damage mechanism under the action of cooling shock, the damage of high temperature granite samples under was analyzed under natural cooling and water cooling conditions by means of thin section observation and SEM scanning technology. The results show that when the heating temperature is increased from 200°C to 800°C, the crack density of the section A at the …

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Prediction Of Burnt Rock Areas And Water Abundance Based On The Electrical-Magnetic Method, Yan Shunshang, Wang Ling, Dong Fangying, Liu Xiao, Lyu Xiaolei Feb 2022

Prediction Of Burnt Rock Areas And Water Abundance Based On The Electrical-Magnetic Method, Yan Shunshang, Wang Ling, Dong Fangying, Liu Xiao, Lyu Xiaolei

Coal Geology & Exploration

For the purpose of accurately ascertaining the distribution range and water abundance degree of the burnt rock mass in the mining area, a new set of methods for prediction and exploration of burnt area boundaries and water-richness is presented based on overall consideration of the electrical-magnetic characteristics of the geological body. Three geophysical prospecting methods including high-precision magnetic survey, transient electromagnetic method and high-density electrical method are used for joint exploration are applied to the exploration of the burnt area of Shajihai No.1 Minefield in Xinjiang. The results show that the southern boundary of the burned area moves slightly compared …

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Detection Performance Of The Azimuthal Electromagnetic Wave Logging Instrument At Coal-Rock Interface In Horizontal Wells, Zhang Yi, Kang Zhengming, Feng Hong, Han Xue, Li Fei, Li Xin Feb 2022

Detection Performance Of The Azimuthal Electromagnetic Wave Logging Instrument At Coal-Rock Interface In Horizontal Wells, Zhang Yi, Kang Zhengming, Feng Hong, Han Xue, Li Fei, Li Xin

Coal Geology & Exploration

The advance and accurate identification of coal-rock interfaces is one of the key technologies to realize intelligent mining, improve mining efficiency and reduce cost. Azimuthal electromagnetic wave logging has achieved good results in lithologic interface identification of petroleum logging, but the identification of coal-rock interface is seldom studied. For the purpose of studying the applicability and detection performance of azimuthal electromagnetic wave in the coalfield logging environment, the one-dimensional generalized reflection coefficient method is used to calculate the magnetic field component, and the fast Hankel transform is used to accelerate the integral calculation speed. What is more, the effects of …

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Development Of A Methane Concentration Monitoring Sensor In Underground Boreholes Of Coal Mines, Cong Lin Feb 2022

Development Of A Methane Concentration Monitoring Sensor In Underground Boreholes Of Coal Mines, Cong Lin

Coal Geology & Exploration

At present, during underground drilling operations in coal mines, the methane concentration monitoring system can only reflect the total drainage volume of methane at the borehole, and cannot observe the effect of methane drainage of a certain section of the borehole. With the increase of the borehole depth for underground methane drainage, the effect of methane drainage changes greatly along the length of the borehole. There is a big difference in the effective extraction radius at different hole depths, leading to greater difficulty in arranging the boreholes for methane extraction, and increased uncertainty. In response to this problem, a methane …

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Development And Test Analysis Of Borehole In-Situ Rock Mass Shear Measurement System, Zhang Youzhen, Liu Yanjie, Zhong Zicheng Feb 2022

Development And Test Analysis Of Borehole In-Situ Rock Mass Shear Measurement System, Zhang Youzhen, Liu Yanjie, Zhong Zicheng

Coal Geology & Exploration

The pre-drilled rock shear measurement system can measure the internal friction angle and cohesion of in-situ rock in mines. Compared with the traditional laboratory test and field tests, such method can keep the essential state of rock mass to the maximum extent, and obtain the test data conveniently and quickly. Firstly, the overall design idea of the system was elaborated, and the pre-drilled in-situ rock shear equipment was successfully developed and the data acquisition and storage software platform was built. Secondly, the test data processing method was developed, based on the working principle of the shearing instrument, and the specific …

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Effects Of Different Tempering Temperatures On The Microstructure And Mechanical Properties Of A Low-Carbon High-Strength Steel, Lu Tian, Wen Guodong, Ma Xiaolin, Li Jun, Ju Pei, Wang Shiqing Feb 2022

Effects Of Different Tempering Temperatures On The Microstructure And Mechanical Properties Of A Low-Carbon High-Strength Steel, Lu Tian, Wen Guodong, Ma Xiaolin, Li Jun, Ju Pei, Wang Shiqing

Coal Geology & Exploration

The mechanical properties of low carbon high strength steel materials used in drilling equipment can be improved effectively by adjusting tempering temperatures of different heat treatments to obtain different material composition. The heat treatment and tempering temperatures were set at 610℃, 630℃ and 650 ℃ respectively, and the microstructure of this low-carbon high-strength steel was compared and analyzed by metallographic microscope and Scanning Electron Microscope(SEM). After tempering, the microhardness, tensile properties and impact energy of the structure were measured respectively by the microhardness tester, universal material testing machine and impact testing machine. The research results show that the performance of …

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Coral Reef Restoration Monitoring Through An Environmental Engineering And Social-Ecological Lens, Michelle C. Platz Feb 2022

Coral Reef Restoration Monitoring Through An Environmental Engineering And Social-Ecological Lens, Michelle C. Platz

USF Tampa Graduate Theses and Dissertations

The Florida Reef Tract (FRT) has experienced catastrophic coral cover declines since the 1970s, and active coral restoration is therefore needed to recover ecosystem integrity, preserve intrinsic values, and guarantee the provision of ecosystem services on which humans rely. While the coral restoration field’s ability to grow and outplant coral has improved extensively in the last two decades, this growth has led to the development of research gaps pertaining to restoration monitoring, specifically regarding the technical capacity to perform long term monitoring, spatial and temporal resolution, and metrics with which to quantify changes in ecosystem function resulting from restoration. The …

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Designing Respectful Tech: What Is Your Relationship With Technology?, Noreen Y. Whysel Feb 2022

Designing Respectful Tech: What Is Your Relationship With Technology?, Noreen Y. Whysel

Publications and Research

According to research at the Me2B Alliance, people feel they have a relationship with technology. It’s emotional. It’s embodied. And it’s very personal. We are studying digital relationships to answer questions like “Do people have a relationship with technology?” “What does that relationship feel like?” And “Do people understand the commitments that they are making when they explore, enter into and dissolve these relationships?” There are parallels between messy human relationships and the kinds of relationships that people develop with technology. As with human relationships, we move through states of discovery, commitment and breakup with digital applications as well. Technology …

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Dissolution Amplification By Resonance And Cavitational Stimulation At Ultrasonic And Megasonic Frequencies, Ross A. Arnold, Shiqi Dong, Longwen Tang, Dale Prentice, Marie Collin, Juan Carlos Vega-Vila, Amaya Hernandez, Erika Callagon La Plante, Kirk Ellison, Aditya Kumar, Samanvaya Srivastava, Mathieu Bauchy, Dante Simonetti, Gaurav N. Sant Feb 2022

Dissolution Amplification By Resonance And Cavitational Stimulation At Ultrasonic And Megasonic Frequencies, Ross A. Arnold, Shiqi Dong, Longwen Tang, Dale Prentice, Marie Collin, Juan Carlos Vega-Vila, Amaya Hernandez, Erika Callagon La Plante, Kirk Ellison, Aditya Kumar, Samanvaya Srivastava, Mathieu Bauchy, Dante Simonetti, Gaurav N. Sant

Materials Science and Engineering Faculty Research & Creative Works

Acoustic stimulation offers a green pathway for the extraction of valuable elements such as Si, Ca, and Mg via solubilization of minerals and industrial waste materials. Prior studies have focused on the use of ultrasonic frequencies (20-40 kHz) to stimulate dissolution, but mega sonic frequencies (≥1 MHz) offer benefits such as matching of the resonance frequencies of solute particles and an increased frequency of cavitation events. Here, based on dissolution tests of a series of minerals, it is found that dissolution under resonance conditions produced dissolution enhancements between 4x-to-6x in Si-rich materials (obsidian, albite, and quartz). Cavitational collapse induced by …

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Influence Of Hydrophobicity On Excitonic Coupling In Dna-Templated Indolenine Squaraine Dye Aggregates, Olga A. Mass, Christopher K. Wilson, German Barcenas, Lan Li, Bernard Yurke, William B. Knowlton, Ryan D. Pensack, Jeunghoon Lee Feb 2022

Influence Of Hydrophobicity On Excitonic Coupling In Dna-Templated Indolenine Squaraine Dye Aggregates, Olga A. Mass, Christopher K. Wilson, German Barcenas, Lan Li, Bernard Yurke, William B. Knowlton, Ryan D. Pensack, Jeunghoon Lee

Materials Science and Engineering Faculty Publications and Presentations

Control over the strength of excitonic coupling in molecular dye aggregates is a substantial factor for the development of technologies such as light harvesting, optoelectronics, and quantum computing. According to the molecular exciton model, the strength of excitonic coupling is inversely proportional to the distance between dyes. Covalent DNA templating was proved to be a versatile tool to control dye spacing on a subnanometer scale. To further expand our ability to control photophysical properties of excitons, here, we investigated the influence of dye hydrophobicity on the strength of excitonic coupling in squaraine aggregates covalently templated by DNA Holliday Junction (DNA …

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Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (4th-Casam-N): I. Mathematical Framework, Dan Gabriel Cacuci Feb 2022

Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (4th-Casam-N): I. Mathematical Framework, Dan Gabriel Cacuci

Faculty Publications

This work presents the fourth-order comprehensive sensitivity analysis methodology for nonlinear systems (abbreviated as “4th-CASAM-N”) for exactly and efficiently computing the first-, second-, third-, and fourth-order functional derivatives (customarily called “sensitivities”) of physical system responses (i.e., “system performance parameters”) to the system’s (or model) parameters. The qualifier “comprehensive” indicates that the 4th-CASAM-N methodology enables the exact and efficient computation not only of response sensitivities with respect to the customary model parameters (including computational input data, correlations, initial and/or boundary conditions) but also with respect to imprecisely known material boundaries, caused by manufacturing tolerances, of the system under consideration. The 4th-CASAM-N …

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Efficient Capture Of Co2 And Its Selective Reduction To Formic Acid Using Tin-Based Nanomaterials, Emmanuel Oluwaseun Abdul Feb 2022

Efficient Capture Of Co2 And Its Selective Reduction To Formic Acid Using Tin-Based Nanomaterials, Emmanuel Oluwaseun Abdul

Dissertations and Theses

CO2 emissions from the combustion of fossil fuels and other anthropogenic sources have become the main contributing factors to global warming. Chemical methods of absorbing/capturing CO2 from combustion flue gases have made it a sought-after approach in engineering emission solutions because of its simplistic and convenient operation and high absorption efficiency. The conversion of CO2 into renewable fuels and high energy density chemicals by clean and economic processes has drawn scientists' attention over the decades. The electrocatalytic conversion of CO2 using Sn-based materials has been demonstrated to be a promising method for producing formate, an important …

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Job Scheduling And Simulation In Cloud Based On Deep Reinforcement Learning, Qirui Li, Xinyi Peng Feb 2022

Job Scheduling And Simulation In Cloud Based On Deep Reinforcement Learning, Qirui Li, Xinyi Peng

Journal of System Simulation

Abstract: To solve the difficulty in job scheduling in the complex and transient multi-user, multi-queue, and multi-data-center cloud computing environment, this paper proposed a job scheduling method based on deep reinforcement learning. A system model of cloud job scheduling and its mathematical model were built, and an optimization goal consisting of transmission time, waiting time, and execution time was obtained. A job scheduling algorithm based on deep reinforcement learning was designed, and its state space, action space, and reward function were given. A simulated cloud job scheduler was designed and developed, and simulated scheduling experiments were conducted on it. The …

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Multi-Floor Evacuation Model Based On Wavelet Neural Network, Juan Wei, Lei You, Yangyong Guo, Zhihai Tang Feb 2022

Multi-Floor Evacuation Model Based On Wavelet Neural Network, Juan Wei, Lei You, Yangyong Guo, Zhihai Tang

Journal of System Simulation

Abstract: Crowd evacuation in a multi-floor environment is a popular social concern, while the stagnation phenomenon easily occurs when simulating a multi-floor complex environment with the traditional social force model. Therefore, An improved social force model is proposed by a wavelet neural network, and a new multi-floor evacuation model is built. In the model, a pedestrian's direction of movement is obtained by the field model, which is used as the self-driving direction of the social force model. Meanwhile, the evaluation indexes of the exit congestion degree, path congestion degree, and average velocity in a multi-floor environment are given, and a …

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Research On Semantic Segmentation Of Natural Landform Based On Edge Detection Module, Qizong Shen, Chunyan Gao Feb 2022

Research On Semantic Segmentation Of Natural Landform Based On Edge Detection Module, Qizong Shen, Chunyan Gao

Journal of System Simulation

Abstract: To classify pixels of natural landform edges in remote sensing images, this paper proposes a multi-channel fusion model and a decoder-side module model both integrating an edge detection module. The edge detection module takes the Canny operator as the base to perform closed operations and mean filtering, as a result of which accurate image edges can be achieved. Based on DeepLabV3+, the semantic segmentation network is connected with an edge planning module in parallel at encoder and decoder sides respectively. The experimental results show that the two improved networks can achieve a better segmentation effect on a high-resolution natural …

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Zoomfft-Based Demodulation Algorithm For Underwater Acoustic Ofdm Signals, Qing Guo, Angdi Li, Jing Wu, Haitao Su Feb 2022

Zoomfft-Based Demodulation Algorithm For Underwater Acoustic Ofdm Signals, Qing Guo, Angdi Li, Jing Wu, Haitao Su

Journal of System Simulation

Abstract: The picket fence effect of fast Fourier transform (FFT) restricts the demodulation performance of the underwater acoustic(UWA) communication systemusing orthogonal frequency division multiplexing (OFDM). To solve this problem, we propose a demodulation algorithm based on ZoomFFT. Specifically, the received signal is processed by frequency shifting and downsampling forarefined spectrum, which improves the spectralresolution and weakens the picketfence effect.Meanwhile, the channel response is refined, and the channel equalization algorithm is constructed on the basis of the minimum mean square error (MMSE) principle to eliminate the channel influence. Simulations show that the performance of underwater acoustic OFDM demodulation algorithm based on …

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Design Of Fatigue Driving Detection System Based On Cascaded Neural Network, Bangqian Ao, Sha Yang, Jinqing Linghu, Zhenhuan Ye Feb 2022

Design Of Fatigue Driving Detection System Based On Cascaded Neural Network, Bangqian Ao, Sha Yang, Jinqing Linghu, Zhenhuan Ye

Journal of System Simulation

Abstract: An algorithm is proposed to greatly improves the face detection rate and ensures the accuracy by adjusting the size of input images, expanding the minimum face size, and reducing the scaling ratio between layers of the detection window. The detection efficiency of this algorithm is 18 times higher than that of the original MTCNN. By building a new CNN structure model for the detection of eyes and mouths, we can achieve network detection accuracy of 95.6%. The proposed network is cascaded with the original MTCNN to continue classifying and locating the eyes and mouth in the formerly …

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Segmentation Line Detection In Dental Model Based On Target Region Constraint, Tian Ma, Yun Li, Jiaojiao Li, Yuancheng Li Feb 2022

Segmentation Line Detection In Dental Model Based On Target Region Constraint, Tian Ma, Yun Li, Jiaojiao Li, Yuancheng Li

Journal of System Simulation

Abstract: It is an important pretreatment of a virtual orthodontic system to accurately segment teeth from a dental model. In the present methods, all patches are computed directly. To solve this problem, this paper proposes a segmentation line detection method based on target region constraint, which narrows down the detection range to the area around the actual segmentation line. In this method, the cutting plane and the cutting line are automatically formed according to the positions of seed points. The detection range is determined by the search for the position with the greatest negative curvature on the cutting line. The …

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Torrefaction Of Oil Palm Empty Fruit Bunch Biomass, Mohamad Azri Sukiran Feb 2022

Torrefaction Of Oil Palm Empty Fruit Bunch Biomass, Mohamad Azri Sukiran

Student Works (2020-2029)

Empty fruit bunches (EFB) have great potential to be used as a renewable fuel. Its current low rate of utilization due largely to high moisture content and low calorific value (CV) can be overcome via a thermal pretreatment namely torrefaction. This study investigated the effects of torrefaction temperature, residence time, particle size and moisture content on EFB’s final products distribution and their characteristics in a fixed bed reactor. The solid products (torrefied EFB) obtained were analyzed by various methods such as proximate and ultimate analyses, CV, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), x-ray diffraction (XRD) and thermogravimetric analysis …

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