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Graphical abstract Highlights • Energy factors were obtained for gasoline and ethanol fueled engines and vehicles. • Use of 3D engine BFSC maps produced consistent results for flexible fuel engines. • Energy conversion factor for E22 was 0.43 L/kW h, from laboratory and road tests. • Energy conversion factor for E100 was 0.62 L/kW h, from laboratory and road tests. Abstract This work investigates the energy factors for fuel conversion from the analysis of brake specific fuel consumption (BSFC) maps of a sample of 15 engines, representative of 75% of current models available in the Brazilian market. The method also employs the engine driving patterns of power output versus crankshaft speed obtained from bench dynamometer tests. The energy factors obtained from the engine analysis was validated against experiments carried out with two production vehicles in laboratory tests following the 1975 US Federal Test Procedure (FTP-75) procedure and road tests following 16 different urban and highway routes. The fuels used in the tests were hydrous ethanol (E100, 6 v/v % water) and a blend of 22 v/v % anhydrous ethanol and 78 v/v % gasoline (E22). The energy factors found from the 3D engine BSFC map analysis were higher than those obtained from the Willans line, currently adopted as a standard, by 52% for E22 and 57% for E100. The results from the 3D engine BFSC maps and the first vehicle following the FTP-75 cycle and 15 road routes were similar, also close to the results from the second vehicle, qualifying them to be representative of modern flexible fuel spark ignition engines and vehicles. [ABSTRACT FROM AUTHOR]

Abstract This study focuses on the energy factor demand of oscillators with the modified Clough hysteretic model subjected to pulse-like near-fault ground motions. First, the definition of the energy factor demand of modified-Clough oscillators was clarified. Then, oscillators covering a reasonable range of nonlinear parameters and dynamic properties were analysed with a constant-ductility-based method, and a ground motion database characterising pulse-like near-fault ground earthquake motions was used as seismic excitations. The influence of the hysteretic quantities on the energy factor demand of the modified-Clough oscillators was discussed based on the statistical results. Comparison between the energy factor demand from the analysis database and the counterparts computed based on the widely used Newmark-Hall model was made. Recognising the limitations of the current design model, an alternative design equation for estimating the mean energy factor demand of oscillators with the modified Clough hysteretic model was proposed using nonlinear regression analyses. The improved accuracy of the developed model was demonstrated. The research findings of this work provide a basis for energy-balance-based seismic design of structures whose hysteretic force-displacement response can be idealised with the modified-Clough model. Highlights • The energy factor of oscillators with the modified Clough hysteretic model is quantified. • The influence of hysteretic parameters is investigated. • The applicability of the current design method is evaluated. • An alternative design equation is proposed. [ABSTRACT FROM AUTHOR]

Heat pump water heater systems (HPWH) introduce new challenges for design and modeling tools, because they require vapor compression system balanced with a water storage tank. In addition, a wrapped-tank condenser coil has strong coupling with a stratified water tank, which leads HPWH simulation to a transient process. To tackle these challenges and deliver an effective, hardware-based HPWH equipment design tool, a quasi-steady-state HPWH model was developed based on the DOE/ORNL Heat Pump Design Model (HPDM). Two new component models were added via this study. One is a one-dimensional stratified water tank model, an improvement to the open-source EnergyPlus water tank model, by introducing a calibration factor to account for bulk mixing effect due to water draws, circulations, etc. The other is a wrapped-tank condenser coil model, using a segment-to-segment modeling approach. The HPWH system model was validated against available experimental data. After that, the model was used for parametric simulations to determine the effects of various design factors. [ABSTRACT FROM AUTHOR]

A novel ultrasonic transducer driving method, in which the power supply to the transducer is regulated by a binary modulating signal, is introduced for the first time for use in direct-contact ultrasonic drying of fabrics. First, the drying characteristics of different fabrics on two types of transducers are studied using continuous transducer driving mode. Then, the effects of duty cycle and frequency of modulating power signals on fabric drying characteristics are investigated. The energy efficiency of the proposed transducer driving method is compared with that of the continuous transducer driving mode. The results suggest that drying using a modulating signal consists of nonlinear and linear regimes similar to those of the continuous driving mode. The results also show that drying time of a fabric depends not only on the fabric type, but also on the duty cycle and the modulating frequency. However, there exists a critical duty cycle beyond which the drying time does not change. The proposed transducer driving method is more energy-efficient compared to continuous driving mode, consuming 7–16 times less energy. Higher energy efficiencies maybe achieved by operating the transducer at higher modulating frequencies and shorter duty cycles. [ABSTRACT FROM AUTHOR]

Lack of concern for spatial variation of urban soil temperature does not reflect the importance of soil temperature in ecosystem service. The method of construction-soil micro gradient transects (CSMGT) and in situ observations were applied in this study to understand the mechanism of higher soil temperatures in urban areas and the spatial variation of the temperature of surface soil layer adjacent to constructions. Based on experimental data, a new theoretical framework for atmosphere-building-soil energy flow systems was established to analyse the changing rate of the temperature of surface soil layer (R S ) adjacent to constructions. The results of redundancy analysis and hierarchical partitioning showed horizontal heat flux between building and soil (HHF 0 ) played a very important role in driving R S along the CSMGT at night, whereas joint effects of multiple energy factors drove it during daytime or on the scale of an entire day. Moreover, a formula was fitted to express the temperature of surface soil layer (T S ) along the CSMGT. Each parameter (a, b and c) of the equation was significant relative to energy or meteorological factors (P < 0.01), and the distribution of the P value of parameter b matched the results of the redundancy analysis and hierarchical partitioning. [ABSTRACT FROM AUTHOR]

The primary objective of this research is to extend energy balance concept in seismic behavior evaluation of low-to-medium rise frame systems with energy dissipation fuses dominated by racking deformations. At its core, energy demand indices under ground motions considering both peak responses and cumulative responses are quantified to develop a dual-energy-demand-indices-based procedure for damage-control behavior evaluation. Firstly, based on the experimentally validated hysteretic feature and representative ground motion ensembles, a parametric study is conducted considering the demand indices of the energy factor and the cumulative ductility. Results of the indices distribution and dispersion are presented in detail. Subsequently, a stepwise procedure that accounts for the peak demand and the cumulative demand is constructed. Then, the procedure is applied in prototype structures for validation. Results indicate that the consideration of dual energy demand indices is necessary for evaluation of systems with fuses, and these indices are influenced by structural nonlinear parameters and ground motions properties. The procedure based on the dual energy demand indices can be used to evaluate the structural damage-control behavior with satisfactory accuracy considering the peak response, the cumulative response, and the energy distribution along stories. [ABSTRACT FROM AUTHOR]

• A new joint vibro-acoustic method for periodic track short-wave defect identification method is put forward. • Based on ACMD and Gini Index, Energy Factor of Vibration Mode (E VM), Energy Factor of Acoustic Mode (E AM) and Energy Factor of Vibro-acoustic Mode (E VAM) are proposed for describing the energy concentration. • The proposed joint vibro-acoustic analysis method can enhance the common components and retain the unique components of acoustic signal and vibration signal. • By analyzing measured data, the proposed method shows effectiveness in identifying short-wave defect and its time–frequency characteristics. The present track short-wave irregularity inspection and evaluation method, based on the vibration signals collected by accelerators mounted on the axle box of high-speed comprehensive inspection train, is relatively a proven technology. However, with data analysis and check on-site, it finds out that the periodic defects exist in the sections where the dynamic responses are weak. When vibration signals are used for short-wave analysis, it may have the problems of inaccurate frequency identification, lack of energy concentration, etc., which is easy to cause missing or misjudgment of defects. As a result, the stability and robustness of present method need to be enhanced and refined. This article analyzes measured acoustic signals for a supplement to vibration signals. Based on vibration signals of axle box and acoustic signals collected by microphones mounted on the bogie frame of high-speed comprehensive inspection train, a new joint vibro-acoustic method for periodic track short-wave defect identification is proposed. The vibration and acoustic signals are processed and evaluated by Adaptive Chirp Mode Decomposition (ACMD), Gini Index (GI) and modal recombination. Energy Factor of Vibration Mode (E VM), Energy Factor of Acoustic Mode (E AM) and Energy Factor of Vibro-acoustic Mode (E VAM) are introduced for evaluating the periodic component in signals. By analyzing three groups of signals, it proves that, combining vibration and acoustic signals, the energy concentration of periodic components can be enhanced without losing the information of other signal components, and the periodic track short-wave defects can be effectively identified. [ABSTRACT FROM AUTHOR]

This research focuses on the seismic energy factor of self-centering systems. Based on energy balance concept, the energy factor of self-centering systems is derived. To clarify the influence of hysteretic parameters on the energy factor, nonlinear dynamic analyses of flag-shaped single-degree-of-freedom systems are performed. An ensemble of near-fault earthquake ground motion records is used as excitations. Numerical evaluations considering different combinations of hysteretic nonlinear parameters including the post-yielding stiffness ratio and ductility factor are performed. A comparison with the widely used design spectra is also made. The dispersion of analyses results is also presented. Results indicate that the energy factor of self-centering systems is appreciably influenced by nonlinear parameters (the ductility factor and post-yielding stiffness ratio). Results of this study are instructive for the revelation of the energy balance mode of self-centering systems, and they can be helpful to enhance and improve the current procedures based on energy balance concept. [ABSTRACT FROM AUTHOR]

Design base shear and lateral force distribution are two important aspects of the seismic design process. Different design methods have been proposed to obtain the design base shear of different types of structures. However, the study related to the lateral force distribution is limited, especially for self-centering (SC) structures. The primary objective of this research is to develop a performance-based seismic design (PBSD) procedure for steel braced frames considering the modified lateral force distribution. Six-story steel braced steel frames are designed to explore the influence of the energy dissipation factor on the lateral force distribution of the frames. Results of nonlinear time-history analyses indicated that the lateral force acting on the roof increases with the decrease in energy dissipation factor. Following the parametric analyses of single-degree-of-freedom (SDOF) systems, the energy factor design spectra are established and the corresponding PBSD procedure for the steel braced frames is proposed. Finally, the four six-story braced steel frames are redesigned using the PBSD procedure with the modified lateral force distribution to illustrate the efficiency of the proposed design method. Analyses results indicate that the steel braced frames designed by the proposed design can satisfy the expected inter-story drift limit with a reasonably uniform distribution of peak inter-story drifts. Furthermore, the 'partial' SC system appears to be a desirable option that effectively controls the residual displacement and peak acceleration responses at the same time, and could achieve a manageable cost control compared to the full SC systems. [Display omitted] • The optimal lateral force distribution of SC and 'partial' SC steel braced frames is investigated. • The energy factor design spectra are established, especially for the 'partial' SC system. • The PBSD procedure considering the modified lateral force distribution for the steel braced frames is proposed. • The 'partial' SC system (e.g., β = 0.75) appears to be a desirable option for the design of steel braced frames. [ABSTRACT FROM AUTHOR]

This communication focuses on the energy factors of systems considering multiple yielding stages during ground motions. Based on an improved energy-balance model, the energy balance of systems is re-established and the energy factor is derived, considering the multiple yielding stages. To comprehensively investigate the influence of yielding stages and critical parameters on the energy factor, nonlinear dynamic analyses of single-degree-of-freedom systems are performed based on the validated numerical tool. Representative numerical evaluations are presented for different combinations of parameters denoting the yielding stages. The results indicate that the energy factor is significantly influenced by the yielding stages of systems. The results of this study are instructive for the calculation of the energy factor of systems showing multiple yielding stages during ground motions, and can be helpful to improve the current procedures based on the energy-balance concept. [ABSTRACT FROM AUTHOR]

• The novel structure showing the partially self-centring behaviour was proposed. • A spectral energy factor model for the system was developed based on the lognormal distribution assumption. • The sufficiency of the energy factor model was justified. To achieve a delicate balance between self-centring behaviour and energy dissipation, it was proposed to develop the damage-control steel frame equipped with shape memory alloy (SMA) connections and ductile links showing the partially self-centring behaviour. This paper examined the inelastic seismic demand of the novel structure, and the emphasis was given to the spectral energy factor of the system subjected to near-field earthquake motions. Based on single-degree-of-freedom (SDF) systems representing the novel structure and a near-field earthquake database, nonlinear spectral analyses were performed considering a wide range of structural period and hysteretic parameters, and more than 25 million energy factors were obtained. The probabilistic characteristics of the energy factors were examined in detail. The analysis database confirmed that the energy factors were sensitive to structural period and hysteretic parameters. In addition, a right-skewed distribution feature of the energy factors was observed. Thus, a spectral energy factor model for damage-control steel frames equipped with SMA connections and ductile links was developed using the lognormal distribution model. Nonlinear regression analyses were conducted to develop a series of prediction equations. The good agreement between the histograms of the energy factor and predictions by the regression equations confirmed the adequacy of the proposed model. The proposed model was eventually applied to evaluating the damage-control behaviour of a prototype structure under near-field earthquake motions, and the sufficiency of the model for assessing the structural damage-control behaviour from a statistic perspective was confirmed. [ABSTRACT FROM AUTHOR]

The tension-only concentrically braced steel beam-through frames are compelling options for low-to-medium rise buildings in low to moderate seismic regions. This paper quantifies the seismic demand of damage-control TCBSBFs under near-fault ground motions. Firstly, the hysteretic model of TCBSBFs in the damage-control stage is validated based on the test database of a prototype structure. Subsequently, representative single-degree-of-freedom (SDOF) systems with the verified hysteretic law are subjected to 320 near-fault seismic records. A parametric study including more than 8,208,000 nonlinear spectral analyses is carried out. The effect of the hysteretic parameters (i.e. the post-yield stiffness ratio and the ductility in the damage-control stage) and the damping ratio on the energy factor is examined in detail. The results revealed that the energy factor demand of bilinear slip kinematic SDOF systems representing the TCBSBFs under near-fault ground motions is sensitive to the hysteretic parameters in the damage-control stage. On the basis of 8,208,000 computed values of the energy factor, the probabilistic distribution of the energy factor exhibits a certain degree of positive skewness. In order to ensure the seismic reliability of TCBSBFs, a probabilistic model of the energy factor governed by the lognormal distribution is developed to facilitate the performance-based seismic design of TCBSBFs. Based on regression analysis of the database, two empirical formulas are proposed for two key parameters. The design model may offer practical guidelines for the design of TCBSBFs. • The SDOF systems were used to represent the TCBSBFs in damage-control stage. • More than 8,208,000 nonlinear SDOF time-history analyses are carried out. • The seismic demand of damage-control TCBSBFs is quantified based on the energy factor. • A probabilistic model of the energy factor is proposed. [ABSTRACT FROM AUTHOR]