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Design and Testing of Transmissive Fresnel Concentration and Thermoelectric Power Generation System
Full text linkIn this paper, a concentrating photovoltaic and temperature difference combined power generation device is designed. The device is guided by the problem of low power generation efficiency of solar cells at high temperature, and transfers the heat of photovoltaic cells to thermoelectric cells to achieve secondary power generation. The research takes the cold end of the thermoelectric battery as the entry point, and studies its influence on the device by controlling the flow rate and temperature of the cooling liquid in the water-cooled radiator. The results show that when the flow rate is 0.5L/min ~ 2.5L/min, the photovoltaic current increases linearly and then increases nonlinearly, while the photovoltaic voltage decreases linearly and then increases nonlinearly. When the water temperature increases from 15°C to 27°C, the photovoltaic current, photovoltaic voltage and thermoelectric voltage decrease with the increase of water temperature, while the thermoelectric current increases with the increase of water temperature. Therefore, selecting the appropriate flow rate and water temperature can further improve the power generation efficiency and performance of the system
Study on Deformation Control during Shield Tunnel Construction Beneath Existing Tunnels
Full text linkThis study is based on the background that the tunnel of Ningbo Metro Line 8 passes beneath the tunnel of Line 1. A three-dimensional numerical model was developed using Midas to simulate the deformation induced by the construction of the new Line 8 tunnel beneath the existing Line 1 tunnel. The results show that the maximum lateral horizontal deformation, longitudinal horizontal deformation, and vertical deformation of the Line 1 tunnel occur after the excavation of the Line 8 tunnel is completed. Notably, all deformations comply with the settlement control standards for existing tunnels in urban rail transit systems in China. After the excavation of the Line 8 tunnel is completed, the maximum surface settlement is less than the settlement control value, indicating that the excavation of Line 8 tunnel has less additional impact on the Line 1 tunnel. It is recommended that, during the construction of the new tunnel, intensive monitoring of the existing tunnel is implemented, particularly focusing on settlement in the central section, to mitigate the risk of structural damage due to excessive deformation
Waste- and Refuse-Derived Fuels: Circular Energy Solutions from Waste Streams
Full text linkThis review explores the potential of waste-derived fuels (WDF) and refuse-derived fuels (RDF) as sustainable alternatives to conventional fossil fuels, addressing both energy recovery and waste management challenges. WDF and RDF are generated from diverse feedstocks—such as municipal solid waste (MSW), industrial by-products, and biomass—via mechanical, thermochemical, and biochemical processing. These fuels can be utilized in cement kilns, power plants, and industrial furnaces, contributing to reduced fossil fuel consumption. The manuscript classifies WDF and RDF into solid, liquid, and gaseous forms, examining their energy characteristics and combustion properties in comparison to coal, diesel, and natural gas. A detailed analysis of calorific value, moisture and ash content, and emissions profiles is provided to assess their performance. The environmental benefits, including decreased landfill usage, methane mitigation, and lower greenhouse gas emissions, are emphasized through life cycle assessments (LCA). Economic aspects such as production costs, energy substitution potential, and global market adoption trends are also discussed. Technological pathways including shredding, drying, gasification, pyrolysis, and anaerobic digestion are analyzed for their efficiency, capital investment requirements, and environmental impacts. The review also highlights current challenges—such as feedstock heterogeneity, emissions control, and public perception—and outlines future prospects enabled by technological advancements, regulatory support, and integration into circular economy frameworks. This comprehensive evaluation positions WDF and RDF as viable contributors to a low-carbon energy future, offering pathways for sustainable waste valorization and renewable energy generation
Improving the Antifriction Behaviors of Steel by Hybrid Treatments of MoS2 and Surface Texture
Full text linkAbstract: In the present paper, the composite coatings with MoS2 and graphite in the epoxy resin were deposited on the textured surface of steel by laser and wire-electrode cutting technology to improve the anti-friction behaviors of the steel. The influences of the content of MoS2 and graphite and the types of surface texture on the anti-friction behavior were studied systematically. The experimental results show that the textured specimens with 1 mm space line and pentagon shape pore exhibit low friction behaviors under dry friction. CoF (coefficient of friction) of the pore and line textured with high content of MoS2 and graphite is reduced by 27.7% and 42.3% under dry friction and by 30.0% and 33.3% under starved lubrication, respectively. CoF of the texture and coating duplex-treated steel is much lower than that of the untreated steel due to the solid lubrication of MoS2 and graphite under dry friction. The possible antifriction and antiwear mechanism is discussed. It is concluded that the duplex-treated steel with the texture and coating exhibits good anti-friction behaviors and the composite coatings with solid lubricant are beneficial to improve the tribological properties of steel under starved and dry friction testing conditions. It is shown that hybrid surface treatment with the texture and solid lubricant coating is an effective way to improve the tribological properties of steel. Solid lubricant coatings deposited on the textured surface can be applied to improve the antifriction behaviors of steel under starved lubrication and dry friction
Constructions of Toroidal Screw Drums
Full text linkAbstract: Design solutions are presented for the implementation of working chambers in the form of relative toroidal screw drums, intended for the finishing treatment of components in the conditions of rotary-screw technological systems
Design and Experiment of a Reconfigurable Bypass Downlink Surface Equipment for Transmitting the Surface Information to Deep Well
Full text linkAbstract: In order to achieve the transmission of the control information from the surface to the downhole in the deep well during drilling, a design method of a new downlink surface equipment for generating negative pulse signals is presented in this paper. The equipment uses adjustable throttle control valve and pressure drop module (PDM) to realize bypass flow control. The PDM uses multistage variable nozzles to reduce drilling fluid pressure and meet drilling requirements under different pressure and flow rates. Design theory of the downlink surface equipment is established, and a specific design instance is given according to actual drilling conditions. Both laboratory and field experimental results verify the correctness of the proposed design method. The research results show that the design equipment can meet the needs of the transmission of the surface information, and the downlink transmission rate can reach at least one-bit data per 8 sec. The maximum pressure drop is realized by the PDM and the pressure drop at the control valve will be reduced according to drilling demand, the fluid velocity in the equipment is reduced as much as possible, the erosion of the drilling fluid to the equipment is reduced, and the service life can be improved effectively
Application of Anal Manometry in the Planning for Anal Fistula Surgery
Full text linkAnal fistula does not heal spontaneously without surgery, and anal function should be preserved after muscle dissection, which is a challenge even to the most experienced surgeon. In order to develop a planner for anal fistula surgery, anal manometry used in the measurement of pressures in the anal canal to investigate the anal function is reviewed. In this review paper, current techniques are described and compared with each other, and technical and clinical challenges are discussed. There are four types of catheters used to measure anal sphincter pressure: water-perfused, solid-state, air-coupled, and fiber optic catheter. Parameters acquired by anal manometry and their relationship with fecal incontinence after anal fistula surgery are discussed. Vectormanometry can provide the pressure profile along the anal canal in three dimensional space, pressure vectorgram, and cross-sectional radial asymmetry, which have more advantages than the conventional method. Understanding the technology and development of anal manometry is critical for the anal fistula surgical planning. A novel design is highly desired for 3D pressure profile measurement along the entire anal canal simultaneously without pulling the catheter
On Semi-Classical Approach to Materials Electronic Structure
Full text linkMaterials atomic structure, ground-state and physical properties as well as their chemical reactivity mainly are determined by electronic structure. When first-principles methods of studying the electronic structure acquire good predictive power, the best approach would be to design new functional materials theoretically and then check experimentally only most perspective ones. In the paper, the semi-classical model of multi-electron atom is constructed, which makes it possible to calculate analytically (in special functions) the electronic structure of atomic particles themselves and materials as their associated systems. Expected relative accuracy makes a few percent, what is quite acceptable for materials science purposes
Physics of a Spinning Object Cyclic Inversion at an Orbital Flight
Full text linkThe opening up of space flights is going on with physical discoveries. One of them was a spinning object cyclic inversion revealed on the MIR space station classified in 1985. Later, the NASA International Space Station openly showed the same effect. This physical effect was an object of stare studying by physicists and mathematicians. They developed only approximated and numerical models on the level of assumptions. The inversion of the spinning objects in the condition of free flight is the subject of gyroscope theory. The mass of the spinning object at the orbital flight generates the system of the interrelated inertial torques that results from the action of the inertial torques produced by the curvilinear motion of the object around the earth. This system of the torques acting on the spinning object at an orbital flight manifests its cyclic inversions, which is the gyroscopic effects. The theory of the gyroscopic effects describes the method of application of the system of the inertial torques, the physics of all gyroscopic effects that manifested by any rotating objects under any condition of their motions
The Extended Bag of Words Model for Visual Recognition and Categorization
Full text linkWith the development of science and technology, more and more images need to be recognized and categorized. Although the classical Bag of Words (BoW) model has played a great role in the past, there are still many limitations about it, i.e. low precision and accuracy, high complexity of computation, etc. In this paper, it is improved and extended from four ways. Firstly, the features filtered from the background are sampled to reduce the influence of background noise. Secondly, the spatial relationship among all features is integrated with the classical BoW vector to improve the accuracy of recognition and categorization. Thirdly, vocabulary tree is constructed by applying hierarchical K mean value, in order to obtain more reasonable vocabulary list and greatly reduce the clustering time. Fourthly, a weighted visual word histogram is considered, in order to stand out the essential difference among images. At last, some experiments are conducted to show the advantage of the proposed method