圆形截面柱的振动台试验及分析

进行了圆柱振动台试验,对模型的加速度反应数据进行获取。试验表明,随着地震的加速度峰值的不断增加,圆柱顶部加速度极值不断增加。柱顶的加速度响应有着增大的趋势,且极值比输入的加速度的极值有一定的放大。     

Domestic demand-side response with heat pumps: controls and tariffs

ABSTRACT

Electric heat pumps feature prominently in projected energy transitions in the UK and elsewhere. Owing to their high electricity consumption, heat pumps are viewed as important targets for demand-side response (DSR). Findings are presented from a field trial of a new control system that aims to optimize heat pump performance, including under time-varying tariff conditions. The trial involved monitoring 76 properties with heat pumps, but without dedicated heat storage; 31 of these received the control system. Interviews were conducted with a subsample of 12 participants. The controller successfully evened out electricity demand over the day (reducing the evening peak), but this was associated with increased late night and daytime temperatures. Interview participants reported some disturbance owing to overnight heating and noise, as well as usability issues with the controller interface and hardware. These issues present risks to the future acceptability of such systems. While the system delivered short-term demand reductions successfully, longer-term demand shifting risked causing unacceptable disturbance to occupants. Future control systems could overcome some of the issues identified in this pioneering trial through more effective zoning, using temperature caps or installing dedicated heat storage, but these may either limit the available flexibility or be challenging to achieve.     

New solutions to the 2D adaptive visual servoing problem with relaxed excitation requirements

In this paper, we present three new globally convergent vision‐based position controllers for a planar manipulator in a fixed‐camera configuration, where the camera orientation and scale factor are considered unknown. This is a basic adaptive visual servoing problem whose solution was hampered by the nonlinear dependence of the system dynamics on the unknown parameters. Proposing a suitable reparameterization of the systems mathematical model, and exploiting some structural properties of it, we propose three different solutions to the problem. The first one is the certainty equivalent version of the known parameter controller and requires some excitation conditions to ensure global asymptotic convergence. A second version of the controller, which is now slightly more complicated and, possibly, needs to inject some high gain but requires significantly weaker excitation conditions, is given. Finally, we propose a slight modification to the second scheme to achieve the trajectory tracking in finite time. The efficacy of the three adaptive controllers is shown through realistic simulations.     

A triple exponentially weighted moving average control chart for monitoring time between events

Time between events (TBE) charts are used in high-yield processes where the rate of occurrences is very low. In the current article, we propose a triple exponentially weighted moving average control chart to monitor TBE (regarded as triple exponentially weighted moving average TEWMA-TBE chart) modeled by a gamma distribution. One- and two-sided schemes of the proposed chart are designed and compared with the double EWMA DEWMA-TBE and EWMA-TBE charts. It is shown that the lower- and two-sided TEWMA-TBE charts outperform its competitors, especially for small to moderate downward shifts, while the upper-sided TEWMA-TBE chart has very good detection ability for small shifts. We also study the robustness of the proposed chart when the true distribution is a Weibull or a lognormal and it is found that the TEWMA-TBE chart has better robustness properties than its competitors, especially for small shifts. Two illustrative examples from airplane accidents and earthquakes are also provided to display the application of the proposed chart.     

Short communication: Repeatability of intravenous glucose tolerance test traits in young Holstein-Friesian cattle

Few studies have compared individual variability of an intravenous glucose tolerance test (ivGTT) obtained daily in young cattle. The objective of this study was to evaluate the repeatability of glucose traits and insulin responses derived from ivGTT during 3 consecutive days in Holstein-Friesian cattle (bulls: n = 4, steers: n = 3, heifers: n = 3). Blood collections were performed from min 0 (basal concentrations) to min 63 (last measurement). Additional estimates included maximal concentration for glucose and insulin, glucose half-life time (GHLT), and glucose and insulin area under the curve. Glucose traits showed higher repeatability when compared with insulin responses. On average, the glucose trait and insulin response with the lowest coefficient of variation was GHLT (0.7%) and insulin area under the curve (21.3%), respectively. In addition, a general linear model with repeated measures was used to test for significant differences in glucose and insulin concentrations over time at different trial days. Both glucose and insulin concentrations were influenced by time point but not by trial day or time point × trial day. The results from this study showed that individual insulin responses were more variable than glucose traits. The high repeatability of GHLT evidenced the strict regulatory glucose disposal mechanisms occurring in young Holstein-Friesian cattle, whereas insulin responses showed high variability despite controlled management and nutritional practices.     

Optical study of twin‐tanked ICS solar heaters combined with asymmetrical CPC‐type reflectors

The distribution of solar irradiance on the absorbing surface of a typical integrated collector storage (ICS) system combined with reflector troughs is commonly studied by means of ray tracing techniques. A conceptually different alternative is offered by the method of the average number of reflections (ANR). In the present work, the latter is employed for the systematic optical study of realistic ICS models. In all cases, the solar devices consist of twin cylindrical storage tanks which are mounted on top of stationary asymmetrical CPC‐type reflectors. The emphasis of the current research is mainly placed on the evaluation of the ANR reliability for the calculation of the optical efficiency of the related twin‐tanked devices. Additionally, useful operational parameters, such as the optical performance of the proposed geometries, are also determined. The behavior of the tested ICS systems reveals that the optical efficiency may vary in the range of 0.75 to 0.91, exhibiting a strong dependence on the geometric parameters of the solar devices. The highest efficiency is achieved by the systems which combine large reflecting area and storage tanks in close proximity.     

Smart dispatching for energy internet with complex cyber‐physical‐social systems: A parallel dispatch perspective

Energy internet (EI) is a complex coupled multienergy system; it is essential to investigate its multienergy dispatching optimization issues. To this end, this paper first proposes a novel conception of smart dispatching for EI with a complex cyber‐physical‐social system (CPSS) network from the perspective of parallel dispatch, called parallel dispatching robot (PDR), and investigates the implementations of PDR based on smart artificial society (SAS) modeling. First, we introduce EI and describe the dispatching issues of EI. Second, we discuss several important concepts supporting the parallel dispatch conception of EI, including knowledge automation (KA), CPSS, and parallel machine learning (PML). On the basis of these, we elaborate the concept of parallel dispatch. Moreover, we construct a large closed‐loop feedback control framework of parallel dispatch for EI integrating a CPSS network based on KA and PML. Third, we establish an experimental platform for PDR research based on the proposed parallel dispatch framework. Fourth, we develop the PML‐based SAS models of a single PDR in centralized dispatching modes and group PDRs in decentralized dispatching modes to achieve crowd wisdom emergence and performance improvement in current cyber‐physical system frameworks of EI. Moreover, we design an external global closed loop for PDR to evaluate its operation stability. Lastly, we conduct a detailed discussion on PDR and offer some prospects for its engineering implementations. The biggest innovation of this paper lies in systematically proposing the smart dispatching concept and framework for complex CPSS‐based EI from the perspective of parallel dispatch and thoroughly investigating how to use SAS modeling to implement parallel dispatching and control for EI considering human and social factors, which is a major extension and theoretical improvement to existing single smart wide area robot concept and a preliminary attempt in investigating a shift from Energy 4.0 to Energy 5.0 in China.     

Influence of nanoadditives on ignition characteristics of Kusum (Schleichera oleosa) biodiesel

Biodiesel obtained from inedible sources emerged as a productive approach in Indian energy scenario due to the scarcity of food resources come up with extensive usage of edible crops. Kusum (Schleichera oleosa) oil is abundantly available in India and can be used as feedstock to produce biodiesel. However, issues such as higher viscosity, poor stability, and lower calorific value result in poor ignition characteristics, hence limiting its use in combustion applications. An improvement in performance and emission characteristics can be achieved by doping nanoparticles in Kusum biodiesel (KBD). The present work examines the impact of a metal compound and carbon‐primarily based nanoparticles on the evaporation time and ignition probability of the KBD. During the experimental process, different fuel samples of KBD were prepared by amalgamating nanoparticles; then, a sequence of hot plate (stainless steel) ignition test was conducted on these test fuels. The comparative assessment of neat biodiesel and the biodiesel fuel doped with 30 ppm each of alumina (Al2O3), and multiwalled carbon nanotubes (MWCNTs) nanoparticles were carried out. The Kusum oil was converted to biodiesel using two‐stage transesterification process. In the initial stage, refined oil was gone through the acid catalyst esterification process followed by the transesterification reaction. The prepared methyl ester was confirmed and characterized using GC‐MS technique. The thermophysical and spray properties of the test fuels including density, viscosity, calorific value, cloud/pour point, Sauter mean diameter (SMD), and specific surface area (SSA) were also calculated. The experimental result showed a significant increase in ignition probability and heat conduction properties due to improved surface area/volume ratio. Also, lower evaporation time was noted for metal/carbon‐based nanoparticles doped biodiesel as compared with neat biodiesel.     

Evaluating sociotechnical dynamics in a simulated remotely-piloted aircraft system: a layered dynamics approach

As coordination mechanisms change and technology failures occur, a sociotechnical system must reorganise itself across human and technological layers to maintain effectiveness. We present a study examining reorganisation across communication, controls and vehicle layers of a remotely-piloted aircraft system (RPAS) using a layered dynamics approach. Team members (pilot; navigator; photographer) performed 5 simulated RPAS missions using different operator configurations, including all-human and human-autonomy teams. Reorganization (operationally defined using entropy) time series measured the changing system reorganisation profiles under different operator configurations and following autonomy failures. Correlations between these reorganisation profiles and team effectiveness scores describe the manner in which the system had to be coordinated to maintain effectiveness under these changing conditions. Four unplanned autonomy failures were analysed to visualise system reorganisation following a technology failure. With its objective and real-time modelling and measurement capabilities, layered dynamics complements existing systems thinking tools for understanding sociotechnical complexity and enhancing system effectiveness.

Practitioner summary: A layered dynamics approach for understanding how a sociotechnical system dynamically reorganises itself is presented. The layered dynamics of RPAS were analysed under different operator configurations and following autonomy failures. Layered dynamics complements existing system-thinking tools for modelling sociotechnical system complexity and effectiveness.

Abbreviation: RPAS: remotely-piloted aircraft system; HIS: human-systems integration; EAST: event analysis of systemic teamwork; H1: hypothesis 1; H2: hypothesis 2; H3: hypothesis 3; CERTT-STE: cognitive engineering research on team tasks--synthetic task environment; AVO: air vehicle operator; PLO: payload operator; DEMPC: data exploitation, mission planning, and communications; ACT-R: adaptive control of thought-rational; sec: seconds; ANOVA: analysis of variance