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In the field of structural analysis dedicated to the study of vibrations of high-speed railway bridges, one reference load model is the well-known HSLM-A, which limits of validity are stated in Eurocode EN 1991-2, Annex E. In a recent paper published in the Journal of Rail and Rapid Transit, the authors investigated the degree of coverage provided by HSLM-A to critical articulated trains. Now in the present article, the authors have extended those analyses to critical conventional and regular trains as well. This is an important aspect because HSLM-A as such is an articulated-type model, so it is of interest to understand how it deals with covering the various resonance phenomena generated by other train types. Therefore, the main goal of this work is to establish whether the conventional and regular trains that stem from the validity rules given in Annex E/EN 1991-2, produce vibratory effects that are duly covered by HSLM-A. Following the aforementioned validity rules, one first aspect analysed is the importance of near-to-integer wheelbase ratios in the coupled vibrations produced by conventional trains. Subsequently, seven realistic, conventional and regular high-speed train models have been synthesised; these models have been made publicly available in Mendeley Data, and comprise almost 3800 different sequences of axle loads. Finally, the response of simply-supported bridges has been analysed with a view to compare the seven synthesised models versus HSLM-A. The exceedance and required speed increase have been computed for both displacements and accelerations, in a comprehensive ensemble of spans and speeds. The results provide a diagnosis of the degree of coverage of HSLM-A with respect to those conventional and regular trains compliant with Annex E/EN 1991-2. [ABSTRACT FROM AUTHOR]

To accurately assess the time dependent reliability of a bridge structure, this work modelled the load using the Generalized Pareto distribution (GPD) and improved the traditional time dependent reliability model. The improved model was validated by a numerical case study with the Monte Carlo simulation (MCS). In addition, the effects of load distributions, load growth rates, live-to-constant load ratios, and resistance degradation functions on the accuracy of the reliability probability were analyzed. Finally, the improved time dependent reliability calculation model was applied to analyze the behaviors of a simply-supported beam bridge. The results confirmed that the improved time dependent reliability model was more accurate than the Generalized Extreme Value (GEV) model, as the GPD model focused on the tail loads that were crucial for structural failure beyond the threshold. The improved time dependent reliability model reduced computational errors caused by uncertainties in load distribution since the computation results were not affected by the overall load distribution. Compared with the GEV model, the improved time dependent reliability model was more sensitive to the load growth rate, and it overcame the shortcomings of the conservative structural safety evaluation. It was worth noting that the accuracy of the improved time dependent model was related to factors such as load growth rate and evaluation base period, but was not affected by the live-to-constant load ratio. To ensure accuracy of structural assessment, we recommend that the base period T should not exceed 10 years. The improved time dependent reliability model demonstrated its ability to accurately capture the time dependent reliability, which can provide valuable insights for safety operation and maintenance strategies of bridges. [ABSTRACT FROM AUTHOR]

Unikernel, as a cutting-edge technology in the field of cloud computing, is characterized by its fast start-up speed and minimal resource usage. However, in the context of large-scale task scheduling in cloud environments, Unikernel currently lacks a customized scheduling mechanism based on its task characteristics, which hinders the further exploitation of its performance advantages. To address this issue, the distinctive task characteristics of Unikernel were initially summarized. Subsequently, a novel multi-level feedback queue scheduling mechanism for Unikernel, referred to as M-RSF, along with its mathematical model, were proposed. Without affecting the structural features of Unikernel, this mechanism could more effectively schedule Unikernel tasks in cloud environments. Meanwhile, a new load model was put forward based on an in-depth analysis of task characteristics. The model not only accurately depicted the task characteristics of Unikernel but also provided a more reasonable value setting for the scheduling policy parameters in M-RSF. Lastly, the implementation and validation of the M-RSF scheduling mechanism on the OSv Unikernel were conducted. Experimental results indicate that M-RSF can effectively reduce the average waiting time and average turnaround time of the OSv Unikernel during large-scale task scheduling, achieving a reduction of more than 15% compared to the unmodified OSv Unikernel.

This study aims to analyze the impact of uniform and eccentric load conditions on the performance of internal feedback hydrostatic thrust and journal bearing. Two distinct models are established: a three-degrees-of-freedom uniform load model and a five-degrees-of-freedom eccentric load model. The support stiffness, overturning stiffness, and flow rate for both thrust and journal bearings are calculated. Additionally, numerical analysis is conducted to examine the influence of oil film thickness, inlet pressure, and restrictor size on the operational characteristics of the bearings, revealing the interplay between an eccentric load and journal bearing speed. The validity of the theoretical algorithm is verified through finite element simulation. The research outcomes hold significant guiding implications for the design and application of internal feedback hydrostatic bearings. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) have significant potential and sustainability in the future transportation sector due to their less pollution and low operating cost. The uncoordinated charging of these EVs may push the power delivery system towards lower performance and even at the risk of damaging the power system equipment. The proper scheduling and coordination of EVs with the system may lessen the negative impact. In this paper, a multi-objective scheduling approach for individual candidate-based EVs is proposed to relieve the distress in power delivery in the best possible way. Minimization of average demand deviation and system unbalance reduction are selected as the objectives to restore the power delivery performance. The proposed approach has been verified on a realistic three-phase power distribution infrastructure. A simple linear regression model is employed to predict the near future number of EVs in the test region. An optimizitaion algorithm based on particle swarm optimization (PSO) technique is operated to find the finest solution satisfying EV charging constraints. The stochastic nature of load demands at the node points of the test network is analyzed with the help of a probabilistic demand model and it is further incorporated into the optimization framework. It is possible to reduce the system's average demand deviation and unbalance level by 53.74% and 51.36%, respectively, with the proposed EV scheduling approach. A comparative study with the existing methods further claims the efficacy of the proposed approach. Framework for home charging schedule of distinct EVs Compliance with multi-objective power supply efficiency Probabilistic modeling of load demand from real collected data Optimization-driven solution for a test case in Mysore city in India [ABSTRACT FROM AUTHOR]

Research on the lithospheric elastic thickness (Te) of lunar mascon basins can provide a deeper understanding of heterogeneous thermal activity. In this study, we focused on four basins (Moscoviense, Freundlich‐Sharonov, Hertzsprung, and Apollo) located on the far side of the Moon. These basins exhibit a significant variation in admittance and correlation spectra, making it challenging to develop precise fitted models. Based on the global lunar crustal thickness model and mare basalt thickness, we developed a mantle and mare basalt load model to estimate the Te. This small Te (10.1 km) suggests a double impact process or extreme thermal activity caused by volcanism during the formation of the Moscoviense. For the typical highland basins, that is, Freundlich‐Sharonov and Hertzsprung, the Te (∼20 km) corresponds to a minimum heat flux of 34 mW m−2. Considering the additional energy introduced by the impact, this heat flux can be considered as the upper limit for the heat flux of the highland itself during the formation of a mascon basin. For the Apollo basin within the South Pole‐Aitken (SPA) terrane, the Te is 30.7 km. The crust beneath the SPA region is thinned, allowing a greater contribution of stiffer mantle material to the lithosphere, perhaps explaining the higher effective Te. Furthermore, the disparity between the highland and SPA terranes can give rise to their distinct basin formation processes. Impact basins formed within the SPA terrane may have experienced a faster cooling process compared to those formed on the highland terrane following the impact event, leading to a higher Te. Plain Language Summary: The study of impact basins on the far side of the moon not only provides valuable insights into the strength of the early growth stage of the lithosphere but also gives a glimpse into the different thermal evolution histories of the lunar highland and the South Pole‐Aitken (SPA). In this study, we construct a lithospheric load model by incorporating the contributions of both mantle plug and mare basalts. The proposed model is applied to the four typical mascon (mass concentration) basins. The smaller elastic thickness of the Moscoviense basin may be attributed to a double shock process or intense thermal activity. The Nectarian Hertzsprung basin is younger than the Pre‐Nectarian Freundlich‐Sharonov basin on the highland. However, the two basins exhibit similar elastic thickness, indicating that the latter have either a slow cooling rate or rapid completion of the super‐isostatic adjustment process. The difference in elastic thickness between the Apollo and the highland basins such as the Freundlich‐Sharonov and Hertzsprung basins could be attributed to variations in geological composition, density, and porosity between the SPA and the highland terrane. Key Points: The smaller Te of the Moscoviense basin suggests that it might have undergone either a double impact process or intense volcanic activityThe elastic thickness of the typical highland mascon basins is about 20 km, corresponding to a minimum heat flux of 34 mW m−2The mascon basins formed in the SPA terrane and the typical highland terrane may experience distinct post‐impact cooling processes [ABSTRACT FROM AUTHOR]

The load can be represented by different models, including static and dynamic representations; each has different responses when analysing a power system, which also impacts the protection system's performance. For instance, in the distance relay, the estimated impedance can present overreach or underreach, affecting the selectivity of the protection and causing malfunction of triggering schemes. Under fault conditions, the load modelling effect can be magnified by the fault resistance effect, where the combination of both effects has not been addressed in the revisited bibliography. The present paper analyses the effect of load modelling for non-bolted faults in the distance relay impedance estimation. Distance relays are of interest due to their wide use in transmission systems and the emerging applications in distribution systems and microgrids. The fundamental contribution of the present paper is to propose a countermeasure for the effects of four different load types and fault resistance. The results demonstrate that the distance estimation is correctly enhanced, and then a close to the real positive sequence impedance is estimated from the relay point to the fault point. The proposal can be included in distance relays without requiring additional hardware, allowing countermeasure of the load type and fault resistance effects.

The national calibration of Eurocode load model 1 (LM1) for road bridges was made by a calibration of the load effects of LM1 against the corresponding load effects of a former load model used in Finland. Due to the increased gross vehicle weights in legislation, a national calibration of LM1 was necessary and the stochastic simulation was needed. The aim of this study is to generate a traffic model together with a predictive model for simulation purposes by using and combining long-time monitoring data measured on a road network in different surveys. In this paper, the performance of the predictive model of increases in axle loads and gross vehicle weights is evaluated against short-term bridge weight in motion (BWIM) measurements. The results achieved with a simulation can be used to gain more information of statistical parameters and the evolution of load effects caused on bridges by road traffic in Finland. The simulation model presented in this study served as a basis for updated national calibration of load model LM1. The follow-up comparison between predictive model and traffic monitoring shows the suitability of the estimation of the evolution of traffic loads and also necessity of the raise of LM1.

This paper first studies the working mechanism of a variable frequency air conditioner, then a detailed modeling of a variable frequency air conditioner is established, in which the motor is equivalent to the third-order induction motor model, so as to obtain the state equation of the variable frequency air conditioner based on the detailed mechanism model. Furthermore, combined with the load voltage and frequency characteristics, the influence of variable frequency air conditioners on the stability characteristics of power system is analyzed through simulation calculation.

The low voltage ride-through (LVRT) characteristics of DPV are first analyzed in this paper, and then the influence of the LVRT control strategies and parameters of PDGs on the grid voltage stability is studied. Finally, the influence of load model with and without DG on grid voltage stability is studied, the simulation results show that it may be too optimistic when new energy sources are not considered.

In order to establish a load model with distributed generation which is suitable for large-scale power system transient simulation under the background of high permeability of new energy, firstly a four machine integrated load model structure that describes the mixing of distributed new energy and traditional load is constructed in this paper, then a reduced order equivalent algorithm for distributed new energy clusters is proposed to determine the parameters of the distributed power equivalent model. Finally, an example is given to verify the effectiveness of the proposed method. The simulation results verify that the proposed method can accurately simulate the comprehensive load characteristics of distribution network with distributed generation.

This study aims to analyze the impact of uniform and eccentric load conditions on the performance of internal feedback hydrostatic thrust and journal bearing. Two distinct models are established: a three-degrees-of-freedom uniform load model and a five-degrees-of-freedom eccentric load model. The support stiffness, overturning stiffness, and flow rate for both thrust and journal bearings are calculated. Additionally, numerical analysis is conducted to examine the influence of oil film thickness, inlet pressure, and restrictor size on the operational characteristics of the bearings, revealing the interplay between an eccentric load and journal bearing speed. The validity of the theoretical algorithm is verified through finite element simulation. The research outcomes hold significant guiding implications for the design and application of internal feedback hydrostatic bearings.

The national calibration of Eurocode load model 1 (LM1) for road bridges was made by a calibration of the load effects of LM1 against the corresponding load effects of a former load model used in Finland. Due to the increased gross vehicle weights in legislation, a national calibration of LM1 was necessary and the stochastic simulation was needed. The aim of this study is to generate a traffic model together with a predictive model for simulation purposes by using and combining long-time monitoring data measured on a road network in different surveys. In this paper, the performance of the predictive model of increases in axle loads and gross vehicle weights is evaluated against short-term bridge weight in motion (BWIM) measurements. The results achieved with a simulation can be used to gain more information of statistical parameters and the evolution of load effects caused on bridges by road traffic in Finland. The simulation model presented in this study served as a basis for updated national calibration of load model LM1. The follow-up comparison between predictive model and traffic monitoring shows the suitability of the estimation of the evolution of traffic loads and also necessity of the raise of LM1. [ABSTRACT FROM AUTHOR]

Natural gas is extensively used as a clean energy source in cities and industries; consequently, there are associated risks of accidental explosions. To reduce the hazards associated with natural gas explosions, it is important to study the inherent laws of natural gas blast loads in unconfined spaces and establish load models. Using experiments on natural gas explosions in unconfined spaces, this study demonstrates the influence of natural gas concentrations, propagation distances, and gas volumes upon explosion loads. A new load model was proposed for the overpressure–time history curves of natural-gas explosions in an unconfined space. A comparison with the empirical model indicated that the predictive effect was superior to that of previous models, such as the TNT equivalent model and the TNO multi-energy model.

The traditional flight load modeling method of complex structure aircraft has the problems of large error and low efficiency. A flight load improved modeling method is proposed,which is comprehensively considering the influence of the bridge index and load equation index on the load model. Taking the multi-beam and multi-wall structure as an example,the load model based on the wing ground load calibration test data of a certain type of aircraft is built. The bending moment and shearing force of improved method and traditional method are compared.The model obtained by the improved method is verified with flight test data. The results show that the flight load improved modeling method is suitable for the load modeling of complex structure aircraft. The improved method can improve the accuracy and iterative stability of the load model while processing ground test data and the load model obtained by the improved method can be used for flight load measurement and safety monitoring.

The existing national standard requires that the contribution of induction motor load to short circuit current be considered, but the lack of induction motor modeling method suitable for power grid simulation calculation in China affects the popularization and application of national standard algorithm. Based on the simulation and calculation of Central China Power Grid, considering the distribution characteristics of medium and low voltage motors on the short-circuit current of high voltage bus, the equivalent method of 110 kV/220 kV bus conversion coefficient of motor contribution short-circuit current in distribution network is put forward.

Formulating accurate dynamic load models is critical for power system analysis, control, and planning. In this paper, a generic dynamic load model is proposed. The dynamic power response of the load is directly approximated as the superposition of various mathematical functions that produce a dynamic response. Basic physical principles of the dynamic process are reflected in the mathematical functions utilized in the proposed model. First, different stages of the dynamic process are detected based on the continuity of derivatives of the measurement. Second, a complete set of mathematical functions that produce the dynamic responses in electric devices are formulated. Third, a parsimonious set of mathematical functions is selected at each stage by performing feature selection using nonlinear principal component analysis. The proposed model is further formulated based on the parsimonious set of mathematical functions at each stage. Finally, the parameters of the proposed model corresponding to different system events are solved. Based on the formulated model, its possible application in event detection is further analyzed. The proposed model is easy to implement given limited data measurement. Various tests on different system event data are performed to validate the effectiveness of the proposed model. The results show that the proposed model has excellent accuracy and robustness for different system events.

For FPGA circuit design, exploring the FPGA design space for the optimal performance becomes important and also challenging. The popular tool COFFE was built on an academic architecture and cannot be applied to modern commercial FPGA chips with the general routing matrix (GRM) architecture. In this paper, we report the design, implementation, and evaluation of our Automated Transistor-level Efficient and Accurate tool, AutoTEA, which extracts the key sub-circuits, uses the initial transistor sizes to construct hspice netlists, and finds the optimal circuit transistor sizes. AutoTEA features accurate area and delay models, and a fast solution space exploration method. We evaluate the accuracy of the area model by comparing with the layout area of a GRM FPGA chip in 28 nm technology. The average area estimation errors are −0.39%, 35.52%, and 9.18% for AutoTEA, COFFE, and a transistor-level automated tool for GRM architecture, respectively. Our load model gives us delay with an average error of −0.90% of the post-simulation delay, while COFFE's average error is 25.75%. Experimental results show that AutoTEA has a speedup of 20X and 2.7X over COFFE and an optimization tool for GRM architecture. Using a cost function that considers both area and delay, we show that AutoTEA is able to improve the area delay product of a previously manually optimized GRM FPGA design by 11%. • AutoTEA is presented for FPGA design optimization. • AutoTEA features accurate area and delay model at advanced nanoscale process to guarantee the quality of circuit optimization. • An efficient and fast convergent search algorithm is proposed for finding the optimal transistor sizes in a vast design space. • A comprehensive comparison of the results was made and some results were validated on a custom designed GRM FPGA chip and a tape-out test chip. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: In this paper, a load model of ONUs is proposed under the condition of one‐to‐many mode matching scenario in multi‐standard virtual passive optical network. By founding the load model of ONUs, the minimum number of loaded ONUs can be realized to reduce the total wavelength tuning times of MT‐ONUs (Mode Transformation ONU). By integrating this model and the optimal combination algorithm, the maximum utilization of the target bandwidth can be carried out. By constructing an establishment and release mechanism of mode matching pairs, frequent switching of working mode of MT‐ONUs can be avoided to effectively lift the operating efficiency and the stability of system and further reduce the number of MT‐ONUs. Simulations show that when the matching bandwidth ratio is between 0.4 and 1, the utilization of total matching bandwidth is greater than 0.95. Finally, by comparison and analysis, the effectiveness of the proposed model is demonstrated. [ABSTRACT FROM AUTHOR]

Long‐Term Measurements of a Post‐tensioned Integral Frame Bridge with Reinforced Concrete Hinges – Comparison of Measurement Results with numerical Simulations – an Observation after 8 Years of Monitoring As part of the research project, initiated by ÖBB‐Infrastruktur AG, the construction of a road bridge within the project Semmering Base Tunnel in Austria with extensive long‐term measurements were carried out from the beginning of the construction works of the bridge in 2014 up to now. The bridge structure consists of an integral prestressed frame bridge with concrete hinges. During the construction of the bridge, monitoring sensors were installed both in the concrete structure before concreting and on the surface of the structure in order to measure deformations, strains, temperature changes and earth pressure stresses. The measurements have now been running for a period of 8 years since the construction of the bridge and the lowering of the formwork. In this context, extensive measurements within an other project were also made and investigations of temperature stresses on bridges as well as laboratory and large‐scale tests on reinforced concrete hinges. The present article describes the construction of the bridge including the erection method and the installation of the monitoring and sensor technology. Over a period of 8 years, the measurement results are presented in the overview as well as in the detailed measurement periods and compared to the calculated approaches. Furthermore, the results of numerical simulations of the concrete hinges were compared with deformations measured in‐situ. The results show a very slow temperature respone due to change of air temperature and small rotations of the concrete hinge. Furthermore, the long‐time deformations of the concrete structure can be clearly identified in the results. [ABSTRACT FROM AUTHOR]

Due to the influence of many factors, the overpressure–time history load model of vented gas explosions is difficult to describe and is not conducive to further structural design. Based on vented gas explosion test data, this paper obtains three typical overpressure-time history curves and puts forward a new semi-empirical model— double hump model that considers gas concentration and venting pressure, and gives a formula for peak pressure and overpressure–time history model. The scientificity of the model is then verified by the total impulse in the load. The model is able directly reflect the load characteristics, provide reference for calculating key parameters of a vented gas explosion and provide information on the structural response under the load. The model thereby has the potential to help reduce the impact of gas explosion disasters.

The multiple-barrier mitigation strategy in the debris-flow source area is an effective approach to inhibit debris-flow entrainment and scale amplification along the flow path. However, less is known as debris flow overflows a filled barrier and cascades downstream. The present study investigates the physical processes and load characteristics of debris-flow overflowing a model flexible barrier, using a well-instrumented medium-scale flume. Volumetric solid concentration is varied ranging from 0.4 to 0.6 so that the control factors (e.g., state of liquefaction and turbulent drag) in the overflow process can be identified. The results demonstrate that effective stress is not observed in the incoming debris flows for solid concentration up to 0.6, denoting a contribution of turbulent drag to the overflow drag. The formed hydraulic jump substantially elevates the overflow depth above the flexible barrier, which has not been considered in the current design guideline. Decomposition of the total overflow load reveals that the increase in total load is actually dominated by the static load due to the elevated flow depth, rather than the turbulent drag. Downward momentum transfer to the lower section of barrier is observed and re-liquefaction of the deposited debris is a prerequisite for the downward momentum transfer. Different from the high solid-concentration cases, the deposit of low solid concentration (0.4) behind the barrier is partially drained with nontrivial effective stress, which further hinders the downward momentum transfer to the base of the barrier. The findings of present study indicate that the debris-flow properties are the key control factors for the complicated debris-barrier interaction. [ABSTRACT FROM AUTHOR]

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Introduction] Load, as the part that ultimately consumes active power, has a very important impact on the stability of the system. Therefore, the influence of different load models on out-of-step oscillation characteristics of power system is studied in this paper. [Method] This paper took a large grid’s regional discontinuity as the research target to comprehensively analyze the effects of different load models on the oscillation center and action of out of step splitting device using BPA program developed by China Electric Power Research Institute. [Result] The simulation results show when using the ZIP static load model, the line Ucos curve demonstrates the best periodic integrity, as the proportion of induction motor type load increases, the Ucos curve’s periodic integrity becomes worse, it even leads to a subversive change in the conclusion whether the out of step splitting device can react. In addition, different load models also cause the oscillation center migration. [Conclusion] Therefore, the credibility of simulation results can only be guaranteed by using the most realistic load model.

In order to promote the consumption of distributed generations and meet the power flow regulation requirements of the distribution network, a novel multiline fast electromagnetic unified power flow controller for the distribution network (D-MFEUPFC) is proposed. It has the advantages of compact structure, fast response, good economy, and high reliability with the traditional regulation mode. Besides, based on multiwinding transformer and hybrid on-load tap changer, D-MFEUPFC can quickly adjust the multiline power flow of the distribution network and absorb the output of new energy. The operating principles and characteristics of the D-MFEUPFC are analyzed to verify the deductions. Then, the multiline power flow equation considering D-MFEUPFC is derived with the comprehensive load model and power injection method, and its control strategy is studied. Finally, the effectiveness of the proposed D-MFEUPFC is proved by simulations and a prototype experiment. The results show that D-MFEUPFC can quickly adjust the multiline power flow within 60 ms, reasonably absorb the output of new energy, and improve the section transmission capacity. Moreover, D-MFEUPFC can realize decoupling control with high compensation accuracy, and the maximum errors of the active power and reactive power are 8.33% and 3.71%, respectively. [ABSTRACT FROM AUTHOR]

Debris-flow impact load is one of the key parameters for design of engineering countermeasures. The multiple-surge load model is a remarkable progress in estimating the debris-flow impact load, which clearly delineates the contribution of each surge to the total impact load and the corresponding acting points. In order to better understand the impact process of channelized debris flow against flexible barrier, a series of medium-scale flume experiments with varying debris-flow volumetric solid concentration (0.40/0.50/0.55) were conducted. Especially, surge impact behavior is focused so that the predictability of the multiple-surge load model could be assessed. The flume and model flexible barrier were instrumented so that both the barrier dynamic response and the debris-flow properties (flow regime) could be correlated to facilitate the assessment. The results show that multiple-surge load model well predicts the total impact load. However, due to the simplification in the impact process, the interaction between the mobile phase (surge) and the deposited phase is ignored, resulting in discrepancy in the load distribution between the model prediction and experimental result. The remixing of deposited debris by the subsequent surges leads to downward momentum transfer to the lower section of barrier, which should be regarded as an adverse scenario of the design of flexible-barrier anchor capacity. [ABSTRACT FROM AUTHOR]

The power consumption of buildings over the course of each minute, hour, day and season plays a major role in how this load influences the Electric Power System voltage and frequency, and vice versa. This consumption is based on the building’s load component types, efficiencies, and how they consume power and react to changes in real time. Due to this complexity, standard full-building load models are typically voltage-invariant. This paper proposes a novel framework to transform these voltage-invariant building load models into fully time- and voltage-dependent load profiles using available data on the voltage sensitivity of individual load components. While a voltage-dependent building model could theoretically be generated from static load models of every component in a building, this approach faces two challenges: first, load models representing all load components are impractical to develop for all possible load component types; second, building energy consumption is never measured or modeled at the individual component level. The proposed framework compiles available component data in the form of static ZIP load model parameters, and maps them into the end use categories utilized by standard building modeling programs. The voltage sensitivity of each end use category is then bounded by the extrema of the component models within it. This framework is applied to a load profile case study representing the aggregate U.S. residential building stock. In addition to the minimum/maximum conditions, a load profile based on typical load composition and weighted ZIP parameters is generated for the same building stock. The results show that for a 10% drop in voltage, using the least sensitive ZIP parameters, active power is expected to be 3% to 14% lower than nominal, depending on the season and time of day. Using the most sensitive ZIP parameters, the active power is expected to be 9% to 20% lower than nominal, also depending on the season and time of day.

New rules for fatigue load models at the guideline for recalculation of road bridges With the revision of the recalculation‐guideline, experiences of the last few years as well as new knowledge on action‐ and resistance‐side aspects of the assessment of road bridges are normatively implemented. One focus is the realistic assessment of fatigue stress. The relevant previous regulations of levels 1 and 2 as well as their current improvements are explained in the article. An important goal of the revision was to be able to take traffic influences into account at level 1 of a recalculation already. Levels 3 and 4 of the recalculation‐guideline cover the measurement‐based assessment and the application of further scientific methods. The knowledge got through structural monitoring is often of great benefit within the recalculation. Additional information on these two levels creates the potential to make even better use of reserves of the structures – a contribution to sustainable use of our resources. [ABSTRACT FROM AUTHOR]

Proposal for a change in the temperature load model for concrete and composite bridges – Results of the research project MTE 2.0 "Modified temperature load model for railway bridges" As part of the research project MTE 2.0 initiated by ÖBB‐Infrastruktur AG, extensive investigations into the actual temperature loads on railway bridges were carried out. As part of the project, measurements on bridge structures as well as evaluations of statistical meteorological climate data over a period of 50 years, probabilistic evaluations and both analytical and numerical calculations were carried out. Based on the results of the project, the design model for temperature loads according to Eurocode 1 was adapted for railway bridges (concrete or composite structures) and a proposal for an optimized temperature load model was newly developed, which is summarized in the following article. Comparative calculations for railway bridges have shown that the elongation of the bridges in the ultimate limit state according to the optimized load model are 25 % to 45 % lower than those based on ÖNORM EN 1991‐1‐5 or ÖNORM B 1991‐1‐5, respectively. Taking into account the partial safety factors and the characteristic values, the actual elongations of existing bridges can be described much more realistically using the newly developed load model. [ABSTRACT FROM AUTHOR]

Location‐specific target load level and object‐specific load models for recalculation based on structural monitoring When evaluating existing bridges, supporting structural monitoring is increasingly being used in order to obtain the stresses in the structure more realistically than purely mathematically and to calibrate the calculation model. The question of how the additional informations obtained through measurements have to be taken into account within the recalculation, including its safety concept, is currently still normatively unclear. On the load side, this can be done through the modified definition of the target load level or, alternatively, through object‐specific load models for load‐bearing capacity and fatigue to map the actual traffic. Furthermore, on the basis of the measurement data, the necessary safety factors can be justified, also taking into account future traffic developments, while maintaining the normatively required level of reliability. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) load and its charging methodologies play a significant role in distribution system planning. The inaccurate modelling of EV load may overload the distribution system components, increase in Network Power Loss (NPL) and Maximum Voltage Deviation (MVD). The Constant Power (CP) load model is more popularly used to model both the conventional and EV loads in the distribution system. But the CP load modelling cannot provide accurate information of EV charging process. In this paper, the EV load is modelled as constant Impedance-constant Current-constant Power (ZIP), Exponential, Constant Current and Constant Power load models and the conventional loads are modelled as Residential–Industrial–Commercial (RIC) and Constant Power load models. With these EV and conventional load models, the optimal site and size of Fast Charging Stations (FCSs) in the distribution system have been determined. Further, to analyse the impact of load of FCSs in the distribution system, the distribution indices are calculated. The multi-objective hybrid SFL-TLBO algorithm has been used to determine the optimal location and size FCSs with the minimization of NPL, MVD and EV User Cost (EVUC) in the distribution system. To consider the uncertainty of the initial SOC of EVs, the Monte-Carlo simulation technique has been used. These studies have been carried out on 38-bus distribution system and substantiate results are presented. [ABSTRACT FROM AUTHOR]

The information contained in this paper will be of interest not only to bridge engineers, but also to train manufacturers. The article provides practical insight into the degree of coverage of real articulated trains (ATs) that Eurocode EN1991-2 guarantees. In both the design of new railway bridges, as well as in the assessment of existing ones, the importance of a detailed knowledge of the limits of validity of load models cannot be overemphasised. Being essential components of the rail transportation system, the capacity of bridges to withstand future traffic demands will be determined precisely by the load models. Therefore, accurate definition of the limits of validity of such models reveals crucial when increased speeds and/or increased axle loads are required by transportation pressing priorities. The most relevant load model for a significant portion of the bridges in high-speed railway lines is the so-called HSLM-A model, defined in EN1991-2. Their limits of validity are described in Annex E of such code. For its singular importance, the effects of vibrations induced by HSLM-A are analysed in this paper with attention to the response of simply supported bridges. This analysis is carried out in a view to determine whether the limits of validity given in Annex E of EN1991-2 cover the largest part of cases of interest. Specifically, the vibration effects of HSLM-A are compared with those of the ATs described in such Annex E, and the response is analysed in depth for simply supported bridges, which are structures especially sensitive to passing trains at high speeds. New theoretical approaches have been developed in order to undertake this investigation, including a novel, simplified expression of the train signature for ATs that is convenient for its low computational cost. The mathematical proofs are included in the first part of the paper and two separate appendices. [ABSTRACT FROM AUTHOR]

The coordination of multiple coupled regulation methods in Internet data centers (IDCs) is proposed in this article to make a full use of IDCs’ spatial and temporal load regulation potentials for demand response (DR). A concise and analytical IDC load model is proposed to facilitate the DR in IDCs. First, the unified IDC load considering multiple coupled regulation methods is modeled represented by workloads and servers. The extra power consumption in IT equipment due to redundancy requirements in computing resources is separated to obtain an explicit mathematical relationship among geo-distributed IDCs. Second, the compatible IDC load model is derived based on a bottom-up approach, where electrical decision variables representing the regulation are introduced to replace non-electrical variables and demonstrate the coupling among multiple regulation methods. Last, a hierarchical control design is deduced to reveal the potentials of the compatible IDC load model in power system applications. Simulations show that the joint implementation of coupled methods can enhance IDC DR capabilities. Simulation results also verify the efficiency of compatible IDC load model in DR and reveal its advantages in load characteristic analyses, computational efficiency, and sensitive information protection of IDCs. [ABSTRACT FROM AUTHOR]

Investigation of actual temperature loads on concrete bridges – Determination of thermal strains Temperature loads are very relevant for the economic dimensioning of structural bearings and expansion joints. In addition, higher temperature loads lead to an increase in restraints when designing integral bridges. The development of a realistic temperature load model is therefore of great technical and economic importance. As part of the project "Modified Temperature Load Model for Railway Bridges (MTE 2.0)", which was initiated by the Austrian Federal Railways, long‐time temperature and deformation measurements were carried out on six concrete bridges. In addition, numerical transient simulations and comparative calculations were performed to investigate the thermal stresses, the temperature gradient and time‐dependent effects (creep, shrinkage). Finally, temperature data from the last 50 years of the Austrian Central Institute for Meteorology and Geodynamics were analyzed using probabilistic methods in order to optimize the correlation between shade air temperature and bridge temperature. These long‐term measurements, simulations and analyzes are the bases for an optimized temperature load model for concrete bridges, which is especially relevant for structures with low slenderness and massive cross‐sections without compromising the reliability of the structure. [ABSTRACT FROM AUTHOR]

This article provides the results of adopting automated monitoring systems designed by the ISI NASU that allow maintaining long-term and energy-saving cast iron production in blast furnaces in Ukraine. The need for adopting these mathematical models is underpinned and the efficiency of their application is shown. [ABSTRACT FROM AUTHOR]

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An integrated Matlab model comprising of an electro-mechanical actuator (EMA) model, load model and state model has been constructed to investigate the cargo door actuator motion control, operation and working states, of which, a Simulink® servomotor system model is adopted to mimic the EMA actuator, a SimMechanics® model is used to compute the actuator's load, a Stateflow® state transition model is employed to simulate the working process. The results indicated that the motion is well controlled, generated load force is valid, working states and their transition logics are reasonable. The simulation verified the effectiveness and easiness of the integrated modelling method.

As the key functional component of the machine tool, the reliability test of the spindle is necessary to verify the reliability of the machine tool. In the reliability test, the cutting load model is the guideline of workload simulation and is the prerequisite to ensure the accuracy and effectiveness of the long-term experiment. However, the existing load models usually aim at the specific cutting force at the tool-tip, thereby ignoring the versatility, maneuverability, and accuracy of the load model when applied in the spindle reliability test. In this study, a general cutting load model for the machine tool spindle is established in a form of radial-axial-torque decomposition, and the radial force is simplified as non-rotating status for the maneuverability of conducting a load simulation. The difference between rotating and non-rotating radial force on the reliability calculation is also discussed and corrected using bearing fatigue analysis. A spindle reliability test platform with radial force, axial force, and torque simulation is developed according to the cutting load model, while the loading spectrum is compiled for conducting the spindle reliability test. This research is of great engineering value for the designing of the spindle reliability test.