Virtual Energy Research Articles

Nonlinear Analysis of Corrugated Core Sandwich Plates Using the Element-Free Galerkin Method

This paper presents a meshless Galerkin method for analyzing the nonlinear behavior of corrugated sandwich plates. A corrugated sandwich plate is a composite structure comprising two flat face sheets and a corrugated core, which can be approximated as an orthotropic anisotropic plate with distinct elastic properties in two perpendicular directions. The formulation is based on the first-order shear deformation theory (FSDT), where the shape functions are constructed using the moving least-square (MLS) approximation. Nonlinear stress and strain expressions are derived according to von Kármán’s large deflection theory. The virtual strain energy functionals of the individual plates are established, and their nonlinear equilibrium equations are formulated using the principle of virtual work. The governing equations for the entire corrugated sandwich structure are obtained by incorporating boundary conditions and displacement continuity constraints. A Newton–Raphson iterative scheme is employed to solve the nonlinear equilibrium equations. The computational program is implemented in C++, and extensive numerical examples are analyzed. The accuracy and reliability of the proposed method are validated through comparisons with ANSYS finite element solutions using SHELL181 elements. The method used in this paper can avoid the problems of mesh reconstruction and mesh distortion in the finite element method. In practical application, it simplifies the simulation calculation and understands the mechanical behavior of sandwich plates closer to actual engineering practice.

Devising a novel evaluation method for computed tomography images containing metal artifacts from titanium seed implants: Application to virtual monochromatic imaging energy optimization.

Metal artifact reduction (MAR) technology cannot fully eliminate metal artifacts from metallic devices in computed tomography (CT) images. Hence, it is important to investigate the optimal acquisition parameters and post-processing techniques. This study aimed to devise a novel evaluation method for images containing metal artifacts from titanium seed implants and identify the optimal energy level for virtual monochromatic imaging (VMI) to reduce metal artifacts and enhance signal detectability. Post-brachytherapy CT scans are a clinical example of the effects of metal artifacts. Therefore, we focused on the pelvic region, including the prostate, and created a phantom with simulated radioactive seeds that were inserted into the prostate region. We investigated the relationship between metal artifacts and monochromatic energy levels (35-200keV at 5keV intervals) using a dual-energy CT system with deep learning (DL) and MAR algorithms. Metal artifacts were investigated using the Gumbel evaluation method, which quantitatively evaluates artifacts, and contrast detectability was assessed using the contrast-to-noise ratio (CNR) and a newly devised contrast-to-artifact ratio (CAR). The location parameter, representing the physical index of metal artifacts, was the lowest at 65keV. CNR and CAR achieved the highest signal detectability at 70 and 65keV, respectively. VMI at 65keV provided an optimal balance. When two images with similar CNR values were assessed using CAR, the resulting difference aligned consistently with the visual evaluation findings. VMI at 65keV with DL and MAR reconstructions is the optimal acquisition parameter for reducing metal artifacts and improving signal detectability. Additionally, CAR can be used to evaluate images affected by metal artifacts. CAR is useful for evaluating the effect of metal artifacts on signal detection.

Sustainable valorization of coal gasification slag through optimized grinding kinetics: Composite cement compressive strength enhancement and environmental assessment.

Sustainable valorization of coal gasification slag through optimized grinding kinetics: Composite cement compressive strength enhancement and environmental assessment.

A quantitative study of virtual energy storage for rural heat pump heating system based on vehicle-to-home technology

A quantitative study of virtual energy storage for rural heat pump heating system based on vehicle-to-home technology

Imaging of Cardiovascular Implantable Electronic Device Leads With Photon-Counting Detector Computed Tomography.

Computed tomography (CT) imaging of cardiovascular implantable electronic device (CIED) leads is currently hampered by large metal artifacts. Recently, photon-counting detector CT (PCD-CT) has been clinically introduced, offering high-resolution imaging with thin slice thicknesses and improved contrast-to-noise ratios. Suspected complications of CIED such as perforation, infection and venous obstruction could potentially be imaged with PCD-CT if metal artifacts were effectively reduced through adapted scan protocols and iterative metal artifact reduction algorithms (IMAR). The study evaluated the impact of various scan and reconstruction parameters, including different IMAR settings, on CIED lead visualization with PCD-CT in order to develop an optimized scan and reconstruction protocol for imaging leads. Five different CIED leads were evaluated in a nonbeating heart phantom using a dual-source PCD-CT with electrocardiography-gated spectral standard resolution (collimation 144 × 0.4 mm) and nonspectral ultra-high resolution (UHR) mode (collimation 120 × 0.2 mm) spiral data acquisition. One scan was performed for each lead and each acquisition mode. Images were reconstructed with different slice thicknesses (0.2 mm, 0.4 mm, 0.6 mm), convolution kernels (Bv40, Bv44, Bv48, and Bv56), virtual monoenergetic energy levels (60-140 keV in steps of 10 keV), without and with different IMAR settings. The extent of metal artifacts was objectively evaluated using 4 different parameters. Additionally, 3 observers subjectively assessed image quality using a 5-point scale. Metal artifacts increased with sharper kernels and higher keV levels in virtual monoenergetic reconstructions. The artifacts were not dependent on slice thickness. No significant differences in metal artifacts were observed between UHR and standard-resolution scans when using similar reconstruction parameters. IMAR effectively reduced artifacts across all kernels, slice thicknesses, and keV levels, with the "neuro coils" setting showing the best performance. Subjective analysis of image quality revealed that thinnest slices and sharpest kernels (0.2 mm, Bv56) allowed for better delineation of fine structures, such as the shape of helices, while reconstructions with thicker slices and softer kernels (0.6 mm, Bv40) were preferred for visualizing general lead appearance and adjacent anatomical structures. Ultra-high and standard resolution PCD-CT with IMAR enables good-quality imaging of CIED leads, showing even small details without compromising the visibility of nearby structures. A dedicated acquisition and reconstruction protocol comprising an UHR scan with 2 reconstructions (0.2 mm/Bv56 and 0.6 mm/Bv40, using IMAR) appears optimal for PCD-CT imaging of CIED leads.

Comparative assessment of energy performance, GHG emission, and environmental performance of exterior wall alternatives for the buildings in an educational campus in Kolkata, India

The building sector contributes to 40% of energy consumption and one-third of the greenhouse gas emissions globally. The building’s energy use involves operational energy (OE) for comfort and operations, along with the embodied energy (EE) embedded in the building materials and the energy spent over the building’s lifetime during building construction and maintenance. This paper aims to establish a methodology for estimating both the embodied and operational energy and embodied and operational GHG emissions of an educational institute campus in Kolkata, India while exploring the cumulative energy and environmental performance of various façade construction materials. The study further identifies the best-performing façade construction material in terms of energy and environmental performance. The embodied and operational energy and the environmental performance of the seven masonry units, two types of mortar, and two kinds of plaster options are compared. The operational energy was in the range of 146 to 166 kWh/m2/Year for the base case, which involved the typically practiced solid burnt clay brick walls. The study revealed, that replacing the conventional solid burnt clay bricks along with cement mortar and cement plaster, with cement stabilized soil blocks in combination of cement mortar and gypsum plaster can curtail the overall energy requirement by 19.35% and improve the environmental performance by reducing the cumulative GHG emissions by 8.31%. A complete life cycle analysis covering the entire building lifecycle stages is also carried out and the cement stabilized soil block walls show 5.0% lesser life cycle energy consumption and 6.14% lesser life cycle GHG emission over the baseline.Graphical

Free vibration analysis of damaged laminated piezoelectric plates and composite plates with piezoelectric patch based on the Extended Layerwise Method

Free vibration analysis of damaged laminated piezoelectric plates and composite plates with piezoelectric patch based on the Extended Layerwise Method

Energy management method of building microgrid considering energy consumption characteristics and virtual energy storage

Energy management method of building microgrid considering energy consumption characteristics and virtual energy storage

Virtual energy storage capacity procurement under multiple operational requirements

Virtual energy storage capacity procurement under multiple operational requirements

Risk-averse energy management of a water-heat-power virtual energy hub considering hosting capacity and Volt-VAR control of distribution network

Risk-averse energy management of a water-heat-power virtual energy hub considering hosting capacity and Volt-VAR control of distribution network

Examining the Impact of House Size on Building Embodied Energy

The effects of buildings on the environment can be reduced with research-based alternative building designs. This study focuses on reducing the building space to lower the overall size of a building as a strategy to reduce the building’s embodied energy. The aim of this study was to investigate the initial embodied energy (IEE) of a residential building that was systematically reduced in size. Using input–output-based hybrid analysis, the IEE for three architecturally distinct four-bedroom residential prototypes (P1, P2, and P3) was calculated. The IEE for P1 (525 m2), P2 (266 m2), and P3 (109 m2) were 3555, 2008, and 1000 GJ, respectively. This indicates a 72% reduction in embodied energy consumption when the largest prototype (P1) was transitioned to the smallest (P3). When analyzing IEE/m2 and IEE/m2/occupant, it becomes apparent that larger spaces tend to have a lower IEE/m2. However, when the occupancy increases, the IEE/m2/occupant decreases by 25–33%. Therefore, considering occupant-centered design for residential buildings, the benefits of a large house are not justifiable. These findings can help inform decisions regarding the optimization of residential spaces to minimize environmental impacts.

Differential Volterra filter: A two-stage decoupling method for audible sounds generated by parametric array loudspeakers based on Westervelt equation.

Parametric array loudspeakers (PALs) produce highly directional sounds due to the parametric process in air. Its application in creating personal audio zones requires simple modeling of the audible sound field near the PAL, which is crucial for subsequent designs to reduce inherent nonlinear distortion. However, current accurate methods for describing the sound field, reliant on numerical solutions to wave equations, are computationally intensive. To achieve both effectiveness and simplicity, this paper proposes a time-domain model for audible sounds generated in the Westervelt far field, called the differential Volterra filter (Diff-VF). It is obtained through two stages: first, a narrow-band (NB) approximation is introduced to decouple the virtual source energy density from interactions of ultrasonic beams when solving the Westervelt equation. This results in a NB Westervelt solution for time-domain inputs. Second, to further develop a generic response independent of inputs, a temporal-spatial discretization is used to simplify the NB Westervelt solution into the Diff-VF model with a one-dimensional kernel. Numerical simulations confirmed the effectiveness of the NB Westervelt solution when compared with an exact solution, whether on- and off-axis. Experimental results validated that the Diff-VF model achieved superior prediction performance over existing VF-based models, with insensitivity to inputs and lower complexity.

Enhancing virtual indoor environment and energy efficiency with real-time BIM and Unreal Engine integration in building lighting design

Enhancing virtual indoor environment and energy efficiency with real-time BIM and Unreal Engine integration in building lighting design

Optimization of virtual energy hub with hybrid vehicles in power-transportation networks towards a low-carbon sustainable transition: A probabilistic regret adjustment

Optimization of virtual energy hub with hybrid vehicles in power-transportation networks towards a low-carbon sustainable transition: A probabilistic regret adjustment

Evaluation of embodied energy and operational energy for panelised building system

The increasing urban population lead to a housing shortage, mainly for the economically weaker sections. Government has come up with few initiatives to implement rapid construction techniques for these housings. Also, construction is an energy-intensive process, and thus it needs a sustainable and energy-efficient approach in executing the modern building system. Panelised prefabrication is one such proven technique. The present work briefly describes the development of sustainable construction products made from locally available agro-industrial ash (AIA) and evaluating their physico-mechanical and functional properties. Two components: Embodied energies (EE) of AIA-based end-products; and computational modelling for determining the peak cooling loads (PCL) are studied. EEs are evaluated through mathematical expressions and compared with traditional practices. The building model comprising both the developed end-products has 23% and 8% reduced EE when compared with burnt-clay and fly-ash brickworks respectively. A computational study for AIA-based building models is made for evaluating the operational energy through a building information modelling tool. PCLs are extracted for different floor combinations of a three storeyed building located in Nagpur, India. The developed combination of prefab systems is compared with conventional practice: fly ash brickwork with RCC framework, and around 53% reduction in PCL was observed.

Coordinated human-exoskeleton locomotion emerges from regulating virtual energy.

Lower-limb exoskeletons have demonstrated great potential for gait rehabilitation in individuals with motor impairments; however, maintaining human-exoskeleton coordination remains a challenge. The coordination problem, referred to as any mismatch or asynchrony between the user's intended trajectories and exoskeleton desired trajectories, leads to sub-optimal gait performance, particularly for individuals with residual motor ability. Here, we investigate the virtual energy regulator (VER)'s ability to generate coordinated locomotion in lower limb exoskeleton. Contribution: (1) In this paper, we experimented VER on a group of nine healthy individuals at different speeds (0.6m/s - 0.85m/s) to study the resultant gait coordination and naturalness on a large group of users. (2) The resultant assisted gait is compared to the natural and passive (zero-torque exoskeleton) walking conditions in terms of muscle activities, kinematic, spatiotemporal and kinetic measures, and questionnaires. (3) Moreover, we presented the VER's convergence proof considering the user contribution to the gait and introduced a metric to measure the user's contribution to gait. (4) We also compared VER performance with the phase-based path controller in terms of muscle effort reduction and joint kinematics using three able-bodied individuals. Results: (1) The results from the VER demonstrate the emergence of natural, coordinated locomotion, resulting in an average muscle effort reduction ranging from 13.1% to 17.7% at different speeds compared to passive walking. (2) The results from VER revealed improvements in all indicators towards natural gait when compared to walking with a zero-torque exoskeleton, for instance, an enhancement in average knee extension ranging from 3.9 to 4.1 degrees. All indicators suggest that the VER preserves natural gait variability and user engagement in locomotion control. (3) Using VER also yields in 13.9%, 15.1%, and 7.0% average muscle effort reduction when compared to the phase-based path controller. (4) Finally, using our proposed metric, we demonstrated that the resultant locomotion limit cycle is a linear combination of human-intended limit cycle and the VER's limit cycle. These findings may have implications for understanding how the central nervous system controls our locomotion.

A comprehensive study on sustainable development of pavement quality concrete utilising fly-ash and copper slag

Huge requirement of aggregates and cement for the construction of a large network of concrete pavements, scarcity of natural resources, degradation of river beds due to unabated extraction of river sand (RS), and increasing generation of industrial wastes, motivate researchers to explore the utilisation of industrial wastes like fly ash (FA) and copper slag (CS) as replacement of OPC and RS respectively in the production of pavement quality concrete (PQC). Earlier studies have reported on the utilisation of these wastes independently for cheap and sustainable concrete. Though all such studies have been found to result in positive and improved results of PQC mixes, it is important to study the strength and durability aspects of PQC mixes containing these two waste materials together, along with cost and environmental impacts in view of ensuring sustainability. To fulfill this objective, forty-eight samples of M40 and M50 grade PQC mixes were prepared by using FA and CS in varying proportions. Compressive and flexural strength tests were conducted to satisfy the strength criteria of PQC mixes. Various durability tests conducted on PQC mixes included accelerated carbonation resistance, chloride resistance, sorptivity, slake durability and abrasion resistance. It is concluded from this study that all PQC mixes with 20% FA and 100% CS replacements have higher compressive and flexural strength as compared with the control mix. The durability characteristics such as resistance to chloride ion penetration, sorptivity value, slake durability and abrasion resistance, of PQC mixes improved. The cost of PQC slab of a a typical design thickness, made with CS and FA was found to decrease by 21%. The environmental factors like global warming potential (GWP) and embodied energy (EE) decreased by 27% and 25.8%, respectively. Considering the strength and durability aspects, cost and environmental impact, replacements OPC and RS by 20% FA and 100% CS respectively, contribute to development of the best satisfying and sustainable PQC mix for paving applications. This study may lead to a sustainable solution for concrete pavement applications which may preserve natural resources, reduce the waste disposal concerns, maintain ecology, and reduce the carbon footprint for future generations.

Durability and microstructure aspects of sustainable concrete made with ceramic waste: a review

The construction industry consumes natural resources rapidly due to the increased population which requires the development of modern buildings. Therefore, several researchers pay attention to promoting sustainable construction. Among different types of waste, ceramic waste (CW) gained attention in concrete production which reduced the waste dumps from the ceramic industry and improved concrete sustainability. Although several researchers recommend the suitability of CW in concrete production. However, a detailed review is required which summarizes all the relevant information and provides compressive information on its impact on concrete performance. Recently, different researchers reviewed the suitability of CW in concrete. However, most researchers focus on strength properties while limited researchers focus on the durability and microstructure properties of CM concrete. Therefore, this review summarized the concrete durability and microstructure aspects with the substitution of CW. The durability performance of concrete was evaluated through percentages of voids, chloride penetration, water absorption, sulfuric acid resistance, shrinkage, freeze and thaw effect, corrosion resistance, and sulfate resistance. Furthermore, microstructure was reviewed through x ray diffraction, thermal stability, pozzolanic activity and scanning electronic microstructure. Also, the review evaluates the environmental and cost-benefits analysis of CW concrete through embodied energy (EE), carbon emissions (ECO2e), and costs. The findings indicate that CW can effectively replace 10%–15% of conventional materials in concrete, offering both environmental and economic advantages.

Optimizing Labor Intensity Improves Economic and Environmental Performances in Pu’er Tea Plantations in China

China stands as the world’s largest producer of both conventional and organic tea. However, the economic and environmental performances of labor input intensity on tea cultivation processes remain understudied at present. For Chinese tea varieties, highly specific distribution of major producing regions always led to variations of tea production under conventional management (CM) and organic management (OM) conditions. Therefore, this study focused on the production of Pu’er tea and thus chose the Yunnan province as the study region, which is the largest Pu’er tea-growing province in China. The study compared the economic and environmental performances between organic and conventional Pu’er tea plantations under different labor intensities by a joint analysis based on economic analysis, emergy evaluation, and environmental footprints. The findings revealed that compared with CM, OM reduced costs by 9.06% ( P < 0.05) and enhanced the ratio of income to cost by 33.00% ( P < 0.05). The emergy sustainability index (ESI) of OM was 33.58% ( P < 0.05) higher than that of CM. The environmental footprint index (EFI) per unit area and per unit economic output for OM decreased by 17.31% ( P < 0.05) and 37.77% ( P < 0.05), respectively, compared to CM. The CM and OM had better economic and ecological benefits when the labor input intensity was 3 to 6 and 8 to 10 persons/hm 2 , respectively. This study provided a novel perspective on understanding the interaction between labor allocation and green income growth in tea production. The findings of this study offered solid scientific evidence and decision support for the green transformation of Chinese tea industry.

Linearized Virtual Energy Tank for Passivity-Based Bilateral Teleoperation Using Linear MPC

Linearized Virtual Energy Tank for Passivity-Based Bilateral Teleoperation Using Linear MPC