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[Springer Series on Atomic, Optical, and Plasma Physics] Gaseous Ion Mobility, Diffusion, and Reaction Volume 105 || Ab Initio Calculations of Transport Coefficients
摘要： There are two main philosophies behind theoretical calculations. The one illustrated in Chap. 9 is to use models of physical phenomenon, specifically mathematical models, that can be solved exactly, either analytically or by numerical methods. Such models often involve adjustable parameters whose values are fit by comparing model results to experimental values; once the parameters are determined, the models are then used to make similar calculations for other situations, ones that were not part of the set used to determine the parameters. The philosophy illustrated in this chapter is to start from our best theories and, as necessary, make approximations to reduce the equations to forms that are practical to solve, again either analytically or numerically. The hope is that, with time, the approximations will improve such that the calculated values match experimental results without using adjustable parameters. In short, the first philosophy is to make exact calculations with approximate theories, while the second is to make approximate calculations with theories that one believes to be exact.
关键词： experimental results,approximations,mathematical models,adjustable parameters,theoretical calculations
更新于2025-09-23 15:19:57
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Wireless Energy Transmission Channel Modeling in Resonant Beam Charging for IoT Devices
摘要： Power supply for Internet of Things (IoT) devices is one of the bottlenecks in IoT development. To provide perpetual power supply for IoT devices, resonant beam charging (RBC) is a promising safe, long-range and high-power wireless power transfer solution. How long distance RBC can reach and how much power RBC can transfer? In this paper, we analyze the consistent and steady operational conditions of the RBC system, which determine the maximum power transmission distance. Then, we study the power transmission efficiency within the operational distance, which determines the deliverable power through the RBC energy transmission channel. Based on the theoretical model of the wireless energy transmission channel, we establish a testbed. According to the experimental measurement, we validate our theoretical model. The experiments verify that the output electrical power at the RBC receiver can be up to 2W. The maximum energy transmission distance is 2.6m. Both the experimental and theoretical performance of the RBC system are evaluated in terms of the transmission distance, the transmission efficiency, and the output electrical power. Our theoretical model and experimental testbed lead to the guidelines for the RBC system design and implementation in practice.
关键词： Wireless Power Transfer,Energy Transmission Channel Modeling,Experimental Testbed,Resonant Beam Charging
更新于2025-09-19 17:15:36
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Determination of electrical characteristics and temperature of PV modules by means of a coupled electrical-thermal model
摘要： Photovoltaic (PV) modules are commonly tested under standard test conditions. However, the performance of the PV module is highly dependent on the location, climate condition, and sun spectrum. Simulation is one of the inexpensive and practical approaches to estimate the performance of PV modules under different climatic conditions. Modeling of PV modules can be complex because different physical phenomena must be coupled and interact with each other. There are several existing multi-physic models, but they are either complex such as numerical models or highly simpli?ed with a lot of assumptions. In this work, we introduce a thermal-electrical model to evaluate the performance of PV modules under different climate conditions based on a previously developed optical-electrical model. The model calculates the electrical parameters and temperature of the PV module after the module reaches the steady-state condition. The temperature, heat ?ow of all layers of the module, and the heat transfer thermal resistances can be determined. Comparison of the simulation and experimental results shows a deviation of around 1%, which indicates that the simulation and experimental results are in good agreement.
关键词： climate conditions,simulation,thermal-electrical model,experimental validation,Photovoltaic modules
更新于2025-09-19 17:13:59
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Facade Integrated Photovoltaic, state of the art of Experimental Methodology
摘要： The concept of Building-integrated Photovoltaics (BIPV) is one of the most promising strategies to employ clean energy in the built environment. Up to now, the PVs have been applied mostly on roofs, but since the total roof area is insufficient, there is a need to integrate photovoltaics on building fa?ades as well. This challenges not only the architectural design of a single building but also the visual image of urban environment, as photovoltaics have to harmonize with conventional building materials used on building facades as brick, concrete, wood, etc. Aiming to provide a foundation for research exploring facade-integration methods that will ensure successful architectural result, the paper presents a state of the art on fa?ade integrated photovoltaics (FIPV) with focus on the experimental research methodology. It embraces both, theoretical research and PVs applications in building projects. As pure computer simulations are not recognized as an experimental methodology, papers conveying such generated results have not been included. In addition, the research that deals exclusively with energy aspects is omitted. The study is based on a comprehensive literature review. Advanced experimental methodologies from selected literature are described and categorized according to the scale (building or urban) and the transparency of the PVs (opaque or translucent). Then detailed features of PV experimental methods are demonstrated in structured tables for analysis and discussion. The study shows that even though solid scientific methods are used to evaluate single features of PVs, e.g. colour or reflectance, there is an obvious lack of methodology providing holistic assessment of Fa?ade-integrated Photovoltaics, especially at the urban scale. The further research will lead toward developing of evaluation criteria framework (in interdisciplinary cooperation) and then provide a holistic methodology combining qualitative and quantitative methods for a successful FIPVs in urban context.
关键词： fa?ade,experimental methodology,architectural perspective,urban context,BIPV
更新于2025-09-19 17:13:59
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Quantitative trade-off analysis of infrared light absorber effects contributed to photovoltaic cells performance
摘要： It is widely known that organic and inorganic coatings absorb more of the solar spectrum, and due to a considerable share of 45% infrared radiation, the energy efficiency drop by the increasing of temperature should be considered. The purpose of this study is to implement a system to characterize silicon solar cell performance and increasing energy efficiency by imposing such coatings as infrared wave absorber to overcome the Shockley–Queisser limit. In other words, this research efforts to improve cell efficiency (coating effects) in addition to imposing the efficiency decreasing effects (temperature increasing). The core of the study is laboratory and experimental set-up measurements to find an organic absorber with the highest absorbance. Ruthenium-based dye, N719, has shown the best performance in experimental conditions and heat extraction to enhance cell energy efficiency. Due to increased absorption in a solar cell (SC), to control the temperature rise of the system, the fan is used as a cooling system. The imposing of N719 results in increasing energy efficiency by up to 1.38%. It is worth noting that a 1.60% increase in energy efficiency is observed due to temperature reduction by 2 degrees.
关键词： Experimental set-up,Photovoltaic cell,Organic absorbent N719,Cooling system,Energy efficiency
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on Meteorology Observations (ICMO) - Chengdu, China (2019.12.28-2019.12.31)] 2019 International Conference on Meteorology Observations (ICMO) - Comparison Test Method and Analysis between Laser Snow Depth Observation Instrument and Manual Observation
摘要： From the sensor principle and design, data processing algorithm were introduced from the aspects such as a laser automatic viewer deep the snow, and in November 2018 - April 2019,The meteorological detection center of the China meteorological administration carried out a comparison test on the equipment of laser automatic snow depth in Aletai prefecture of Xinjiang in winter.This paper provides a very complete snow depth comparison test method to evaluate and analyze the observation data in terms of accuracy, data stability and data integrity. The differences in the data analyzed by the comprehensive test were mainly caused by the wind speed, the mixture of ice water and the large temperature difference between day and night. Through the consistency analysis between the data of automatic snow depth equipment and the manual standard data, the measurement accuracy reaches the requirements of the "specification for ground meteorological observation". The laser automatic snow depth equipment can continuously and accurately reflect the change of snow cover. Finally, the existing problems of the laser snow depth observation instrument are discussed and some Suggestions for improvement are put forward.
关键词： Contrast test,Experimental difference,Laser automatic snow depth observation instrument,Consistency analysis
更新于2025-09-19 17:13:59
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A laser triangulation sensor for vibrational structural analysis and diagnostics
摘要： The industrial progress has reached a level in which it is necessary to understand the behavior of mechanical components and to monitor their conditions without disassembling them. Nowadays, a suitable methodology is based on vibrational analysis usually performed through acceleration signals measured directly on the system to be tested. However, in the last years, the industrial scenario has deeply changed due to the need for time reduction, in particular, for the control operations at the end of the productive line. The genuine methods based on acceleration measurements, for example, through piezoelectric accelerometers, came into conflict with the industrial need as the sensors used for the quality control have to be easily and fastly mounted and unmounted. A valid alternative is represented by the exploitation of laser triangulation sensors that are able to measure the dynamic displacement in a contactless way, strongly reducing the (un)mounting time. The target of this paper is to highlight pros and cons of the contactless displacement analysis through laser triangulation sensors with respect to the contact one through genuine accelerometers by means of a comparison between the results obtained both for experimental modal analysis and vibrational diagnostics of rotating machines.
关键词： displacement analysis,experimental modal analysis,laser triangulation sensor,Vibration,vibrational diagnostics
更新于2025-09-19 17:13:59
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Simulation and Experimental Comparison of Laser Impact Welding with a Plasma Pressure Model
摘要： In this study, spatial and temporal pro?les of an Nd-YAG laser beam pressure pulse are experimentally characterized and fully captured for use in numerical simulations of laser impact welding (LIW). Both axisymmetric, Arbitrary Lagrangian-Eulerian (ALE) and Eulerian dynamic explicit numerical simulations of the collision and deformation of the ?yer and target foils are created. The e?ect of the stando? distance between the foils on impact angle, velocity distribution, springback, the overall shape of the deformed foils, and the weld strength in lap shear tests are investigated. In addition, the jetting phenomenon (separation and ejection of particles at very high velocities due to high-impact collision) and interlocking of the foils along the weld interface are simulated. Simulation results are compared to experiments, which exhibit very similar deformation and impact behaviors. In contrast to previous numerical studies that assume a pre-de?ned deformed ?yer foil shape with uniform initial velocity, the research in this work shows that incorporation of the actual spatial and temporal pro?les of the laser beam and modeling of the corresponding pressure pulse based on a laser shock peening approach provides a more realistic prediction of the LIW process mechanism.
关键词： laser impact welding,?nite element simulation,experimental analysis,high-velocity impact welding
更新于2025-09-16 10:30:52
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Finite Element Modelling and Analysis for Dynamic Investigation of a Laser Spot Welded Hat-Plate Structure under Initial Stress Influence
摘要： This paper presents the finite element modelling and analysis of the dynamic behaviour of a laser spot welded structure under the influence of initial stress. Modal based updating with a new scheme was used to improve the finite element model of the structure. Element connectors with CWELD ELPAT format were used to represent the laser spot welded in the structure. The modal parameters of the structure were measured using impact hammer testing and roving accelerometers under free-free boundary conditions. NASTRAN SOL 200 was used in updating the finite element model in light of the experimental results. In this study, it was found that modal updating with the new scheme has successfully matched the finite element model of the welded structure with the experimental model. The achievement demonstrates the accuracy and efficiency of the proposed new scheme.
关键词： Finite Element Analysis,Initial Stress,Experimental Modal Analysis,Model Updating
更新于2025-09-16 10:30:52
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Experimental design investigation of through-transmission laser welding of dissimilar polymers
摘要： In the present study, the laser weldability of several types of dissimilar polymers couples are investigated using the experimental design method. This experimental strategy allowed to quantify the influence of the operating parameters on the failure force of the welded specimens. Some preliminary tests were used in order to find the initial conditions for the design of the experimental matrices. Based on the conclusions drawn from these preliminary tests, exploratory experimental designs were used to advance towards the optimum for each couple of polymeric materials. The polymeric materials considered were: ABS and PA11 with different pigments and thickness. One could note that the laser power used is the most important parameter on the mechanical resistance and the weldability is assured in a narrow interval of power laser. An important clamping pressure and two laser passages are useful to improve the performances of the weld strength.
关键词： mechanical resistance,laser welding,weldability,dissimilar polymers,experimental design
更新于2025-09-16 10:30:52