Dynamic Energy Research Articles

A flexible design framework for lattice-based chiral mechanical metamaterials considering dynamic energy absorption

While chiral mechanical metamaterials (CMMs) are reported promising in energy absorption due to the unique chiral effect, the energy-absorbing CMMs lack effective and generalized design methodologies and corresponding structure-property relationship studies. To this end, a design framework for lattice-based CMMs was proposed, and the dynamic compressive behaviors of CMMs were systematically investigated. Firstly, based on a predefined design baseline that considered a support-free metal additive manufacturing process, a screw-theory-based assembly rule was presented, which enabled the scalable twist effects and the characterization of chiral features. Secondly, an aperiodic design process that sequentially defines joints, strut connections, and geometrical features was proposed. This framework via parameterization enables the rapid generation of geometric and finite element models that contain a large number of unit cells. It also enables the integration of joint enhancement design, bio-inspired helical design, and gradient design. Finally, by finite element analysis and experiments of uniaxial medium-strain-rate (50 s−1) compression, the effects of chirality on mechanical properties (compressive strength, yield plateau, energy absorption, etc.) during the nonlinear large-deformation responses were elucidated. Results show that a comprehensive and flexible method is presented by independently defining each rod component or joint of the lattice type metamaterials, which enables the design from chiral to achiral, from rectangular to helical, and from uniform to gradient. The bidirectional gradient CMMs design along the axial and radial directions achieves a 52.0 % specific energy absorption enhancement compared with achiral lattices, demonstrating the energy absorption advantage of CMMs, and laying the foundation for further optimization, inverse design, and engineering applications.

Enhanced energy harvesting from random excitations: A dynamic amplifier-augmented hybrid bistable piezoelectric energy harvester

In the energy harvesting field, it is critical to efficiently convert ambient vibrations into usable electrical energy, especially under conditions characterized by low amplitude and random excitations. This study introduces a novel hybrid bistable piezoelectric energy harvester (HBPEH) designed to optimize energy conversion in challenging environmental conditions. The HBPEH features a unique piezoelectric cantilever beam integrated with a dynamic amplifier at the fixed end, significantly enhancing both rotational and lateral displacements of the beam. This innovation lowers the threshold for snap-through events, crucial for maximizing energy transfer in bistable systems, and enables superior energy harvesting capabilities. Furthermore, the HBPEH demonstrates significantly higher power outputs when subjected to excitation intensities beyond critical levels, outperforming conventional energy harvesters. Extensive numerical and theoretical analyses confirm that the HBPEH offers a promising solution for applications hindered by suboptimal energy conversion rates. Its ability to operate effectively under diverse and unpredictable excitation conditions underscores the HBPEH's robustness and superiority in advanced energy harvesting scenarios. The design improvements introduced in this study highlight the potential of the HBPEH to transform energy harvesting approaches. By addressing the limitations of traditional harvesters, the HBPEH provides enhanced efficiency and reliability, making it suitable for a broader range of practical applications in variable environmental conditions.

Cost-Optimality Assessment of a Solar Trigeneration System for Tertiary Sector Buildings in Greece

To pave the way towards buildings’ decarbonization in the context of the European Union’s (EU) policy, the methodology of cost-optimality assessment based on regulation 244/2012/EU is a useful tool to explore and foster the application of energy technologies in buildings. Meanwhile, the fostering of concentrated solar power is included in the EU solar energy strategy. In this study, the cost-optimal methodology is employed for the techno-economic assessment of the integration of a novel solar, multi-purpose energy technology, namely a parabolic trough collector-based trigeneration system, in two building types with different characteristics, namely an office and a hospital, in Greece, thus allowing the evaluation of the cost-optimal system design and the impact of the building type on the system’s techno-economic performance. Reference buildings are defined and their energy demand is calculated through dynamic energy simulations. The trigeneration system’s performance for different design scenarios is then parametrically investigated using a simulation model. For each scenario, energy, environmental and economic indicators are calculated and the cost-optimal designs are extracted. In the cost-optimal implementation, the system covered 18.19–36.39% and 3.58–15.71% of the heating and cooling demand, respectively, while the reduction of the primary energy consumption and emissions was estimated at 10–14% and 10–16%, respectively. However, differences between the buildings related to the operation schedule and the loads led to the implementation of the system being economically more attractive in the hospital, while for the office, financial support is necessary for a viable investment.

Integrating electric vehicles into hybrid microgrids: A stochastic approach to future-ready renewable energy solutions and management

As electric vehicles (EVs) continue to rise in popularity, there has been an intensified focus on the distribution of power within hybrid renewable energy systems. In this context, the significance of vehicle-to-grid (V2G) and grid-to-vehicle (G2V) models for mitigating grid pressures has been increasingly recognized. These models help mitigate grid pressures by using EVs as reliable loads. This research delves into the technical and economic aspects of a hybrid microgrid integrated with various components such as photovoltaic panels (PVs), wind turbines (WTs), battery energy storage systems (BESSs), and EV grid connections, situated at a specific latitude of 40°39.2′N and longitude of 29°13.2′E. The methodology employed is grounded in advanced stochastic metaheuristic approaches. The infrastructure accommodates two distinct loads: a primary load and another dedicated to EV charging. The cornerstone of the energy framework is renewables, particularly PV panels and wind turbines. A dynamic rule-based energy management scheme is implemented to ensure consistent fulfillment of energy demands with an emphasis on cost efficiency. In defining the dimensions of the microgrid, various algorithms including the Coati Optimization Algorithm (COA), Driving Training-Based Optimization (DTBO), Particle Swarm Optimization (PSO), Genetic Algorithm (GA), Turbulent Flow of Water-based Optimization (TFWO), White Shark Optimizer (WSO), Zebra Optimization Algorithm (ZOA), and Flying Foxes Optimization (FFO) were used. This configuration was evaluated in terms of the annual system cost, present-day value, loss of power supply probability (LPSP), and leveled cost of energy (LCOE). Thanks to the strategic deployment of the TFWO algorithm, optimal results were achieved for the system, including a PV capacity of 411.0560 kW, a WT capacity of 327.0229 kW, and a BESS capacity of 561.1750 kW. With this configuration, the annual cost of the system was determined to be $4.0499 × 105, the present value was set at $4.6452 × 106, the nominal LPSP was calculated at 0.0487 %, and the LCOE was established at $0.1597/kWh. Notably, a significant portion of the energy demand, approximately 69.87 %, was met through renewables, with the remaining 30.13 % covered by traditional sources. Comprehensive sensitivity analysis of key parameters enabled forecasting of future trends. All research activities underwent thorough review, confirming the TFWO algorithm's superior efficiency and faster convergence compared to other methods. The optimization algorithms were implemented in MATLAB 2022b, and statistical evaluations performed using the R programming language.

A New Tailored Approach to Calculate the Optimal Number of Outdoor Air Changes in School Building HVAC Systems in the Post-COVID-19 Era

Air conditioning systems can play a positive or negative role in the spread of COVID-19 infection. The importance of sufficient outdoor air changes in buildings was highlighted by the World Health Organization, therefore these should be guaranteed by mechanical ventilation systems or adequate air conditioning systems. The proposed case study concerns the optimal number of outdoor air changes to limit COVID-19 contagion for a school building in Central Italy. The Wells–Riley model is used to assess the risk of airborne infection, while energy consumption is calculated by a dynamic energy simulation software. The scope of the paper offers an innovative method to define the optimal ventilation strategy for the building’s HVAC system design to reduce the risk of infection with limited increases in energy consumption and greenhouse gas emissions. Results show that the desirable approach is the one in which the same low value of contagion risk is set in all rooms. This new approach results in significant energy savings, compared to the most common ones (setting the same high outdoor air rates for all rooms) to counteract the risk of infection. Finally, the zero-emission building target is verified by introducing a suitable photovoltaic system to offset pollutant emissions.

The binding pattern of ferric iron and iron-binding protein in Botrytis cinerea

Iron-binding protein (Ibp) has protective effect on pathogen exposed to H2O2 in defense response of plants. Ibp in Botrytis cinerea (BcIbp) is related to its virulence. Bcibp mutation lead to virulence deficiencies in B. cinerea. BcIbp is involved in the Fe3+ homeostasis regulation. Recognition the binding site and binding pattern of ferric iron and iron-binding protein in B. cinerea are vital to understand its function. In this study, molecular dynamics (MD) simulations, gaussian accelerated molecular dynamics (GaMD) simulations, dynamic cross correlation analysis and quantum chemical energy calculation were used to explore binding pattern of ferric iron. MD results showed that the C-terminal region had little effect on the stability of residues in the Fe3+-binding pocket. Energy calculations suggested the most likely coordination pattern for ferric iron in iron-binding protein. These results will help to understand the binding of ferric iron to iron-binding protein and provide new ideas for regulating the virulence of B. cinerea.

Dynamic analysis and energy harvesting of a portal frame that contains smart materials and nonlinear electromagnetic energy sink

Dynamic analysis and energy harvesting of a portal frame that contains smart materials and nonlinear electromagnetic energy sink

New Way for Solving Naiver - Stokes Equation

This paper gives a new way for solving Navier - Stokes equation (N - S equation for short in following) by using following steps: Step 1, Sets up Wind - Pressure/density equation (1), suits for points in air (na∈A=∪na) and solves solutions ua and pa/ρa. (1 s). Step 2. Sets up Wave equation, described by NS equation (2), suits for points in sea (ns∈S=∪ns), and solutions us and ps/ρs. (2s) (unknown) Step 3. Sets up Wind - Wave equation (3), by (3) = (1) ∩ (2), suits for points in boundary between air and sea. (nas∈A∩S) and their solutions: ua,us and pa/ρa , ps/pa/ρa, .(3s). Step 4. Sets up boundary conditions by For differential form, ua= us and pa/pa = ps/pa. (4s1). For integral form. The wind dynamic energy = Potential energy of the high of sea. (4s2). Now, we have : the solutions of (2s) is solved by (3s) and by (4s1), i.e., ua = us and pa/ρa = ps/ρs. Or (1) = (2) . Then (2) is solved.

Proposal of an Original Methodology to Evaluate the Performance of Chipper Machines

Wood fuel from the agroforestry sector is one of the main strategies cited by the EU for reducing energetic dependance on foreign markets. Its sustainability, both economic and environmental, can be improved through the optimization of harvesting and chipping operations. This study was focused on the dynamic and energetic balance of the chipping phase carried out by a chipper operated by the power-take-off (PTO) of a medium-power tractor. Both machines were equipped with sensors for real-time monitoring of fuel consumption, PTO torque and speed, trunk diameter and working time during the comminution of 61 poplar trees grown in a medium rotation coppice system. The data analysis was carried out on the entire dataset (about 29,000 records) without considering their belonging to different trees. By means of proper data ordinations, it has been possible to define all the intervals in which the chipping stopped (e.g., between two trees) and to exclude them from the intervals of actual chipping. This has allowed forcomputation of operative and actual working time, as well as of the basic power required to operate the chipper and the power for actual chipping. Subsequently, the parameter values observed during actual chipping were related to the cutting diameters measured at the same instant. Subsequently, the dataset was divided according to seven diameter classes, and, for each class, the descriptive statistical indices of working time, work productivity, CO2 emissions, energy requirement and fuel consumption were calculated. Eventually, the correlation between the variations in trunk diameter and other parameters was verified both on the whole dataset and based on the class average values. The analysis made it possible to identify the conditions of greatest efficiency for the chipper. More generally, the method could help to increase the accuracy of measurements aimed at characterizing the performance of chippers from the point of view of dynamic energy requirements as well as in relation to different wood species.

Tailored and Externally Corrected Coupled Cluster with Quantum Inputs.

We propose to use wave function overlaps obtained from a quantum computer as inputs for the classical split-amplitude techniques, tailored and externally corrected coupled cluster, to achieve balanced treatment of static and dynamic correlation effects in molecular electronic structure simulations. By combining insights from statistical properties of matchgate shadows, which are used to measure quantum trial state overlaps, with classical correlation diagnostics, we can provide quantum resource estimates well into the classically no longer exactly solvable regime. We find that rather imperfect wave functions and remarkably low shot counts are sufficient to cure qualitative failures of plain coupled cluster singles doubles and to obtain chemically precise dynamic correlation energy corrections. We provide insights into which wave function preparation schemes have a chance of yielding quantum advantage, and we test our proposed method using overlaps measured on Google's Sycamore device.

Impact-induced energy release characteristics of Ti-Zr-Hf-Ta high-entropy alloys by using a temperature-pressure synchronous measurement method

Energetic structural materials (ESMs) are a new type of materials with structural strength and reactivity, and their impact-induced energy release characteristics are greatly influenced by the fragmentation behavior. In this study, the dynamic fragmentation behavior and energy release characteristics of Ti-Zr-Hf-Ta high-entropy alloys (HEAs) with different precipitate content were investigated based on split Hopkinson pressure bars (SHPB) tests. To quantitatively evaluate the reactivity of ESMs, a temperature-pressure synchronous measurement method combined with a modified calculation model for quasi-sealed chamber was proposed. The results showed that the precipitates were distributed at the grain boundaries. As the precipitate content increased, the quasi-static yield strengths increased from 1004 to 1132 MPa, the dynamic yield strengths increased from 1672 to 1874 MPa, while the fracture strains decreased from 0.47 to 0.29, and correspondingly, the released energy increased from 14±2–511±154 J/g. The results demonstrated that the impact-induced energy release characteristics of the materials are closely related to the fracture strain. It can be confirmed that the alloys with lower plasticity are more likely to fracture under impact conditions, and the combustion reaction will be more violent, which is well consistent with the measurement of the energy-release amounts. High-speed infrared temperature measurement and microstructural photography also provided the underlying mechanism: the fragment size of low plasticity materials is smaller and the local hot spots are more dispersed, both of which are conducive to the combustion reaction. By using this method, the relationship among mechanical properties, fragmentation behavior, and energy release characteristics can be established, and the results will provide new insights into the development of ESMs with superior energy release under impact loading and applicable mechanical properties for potential applications.

Superposition principle of impact on the working environment of actuating elements for site preparation machines

Problem. The analysis of the ripper working elements designs showed that their improvement perspective direction is using vibration and impact actuating elements. They work by the principle of dynamic energy accumulation with its subsequent use. However, there are currently no approaches to determining the tip rational parameters with the dynamic cutting edge. Goal. The main hypothesis formation and justification of the superposition principle impact on the working environment of actuating elements for ripper-pick. Methodology. Analytical methods of studying the soil destruction process by site preparation machines equipped tip with a dynamic cutting edge were used. Results. The presented model that describes the soil destruction process by the tip with the dynamic cutting edge has been developed. It combines the work of static force, determined by the traction parameters of the base machine, and the work of dynamic forces, determined by the physical and mechanical conditions of the soil destruction process. As a result, we obtained an equation for determining the force to overcome soil cutting resistance by the tip with the dynamic cutting edge. Originality. We propose to apply the superposition principle of effecting several factors on the working environment simultaneously in the soil destruction process by ripper-pick, such as static and dynamic load, due to the possibility of energy accumulation with subsequent use. This would create the high-speed power pulse on the cutting edge to ensure the preliminary formation of the compressed zone in the massif, with decreases in the power intensity of the static load for complete separation of the soil element. Practical value. The presented hypothesis will allow the technological basis development of such systems creation and application to develop fundamentally new technical solutions, to create effective, safe and durable working elements.

A dynamic energy budget (DEB) model to assess the sublethal effects of imidacloprid toward Gammarus pulex at different temperatures

Environmental ambient temperature significantly impacts the metabolic activities of aquatic ectotherm organisms and influences the fate of various chemicals. Although numerous studies have shown that the acute lethal toxicity of most chemicals increases with increasing temperature, the impact of temperature on chronic effects — encompassing both lethal and sublethal endpoints — has received limited attention. Furthermore, the mechanisms linking temperature and toxicity, potentially unveiled by toxicokinetic-toxicodynamic models (TKTD), remains inadequately explored. This study investigated the effects of environmentally relevant concentrations of the insecticide imidacloprid (IMI) on the growth and survival of the freshwater amphipod Gammarus pulex at two different temperatures. Our experimental design was tailored to fit a TKTD model, specifically the Dynamic Energy Budget (DEB) model. We conducted experiments spanning three and six months, utilizing small G. pulex juveniles. We observed effects endpoints at least five times, employing both destructive and non-destructive methods, crucial for accurate model fittings. Our findings reveal that IMI at environmental concentrations (up to 0.3 μg/L) affects the growth and survival of G. pulex, albeit with limited effects, showing a 10% inhibition compared to the control group. These limited effects, observed in both lethal and sublethal aspects, suggest a different mode of action at low, environmentally-relevant concentrations in long-term exposure (3 months), in contrast to previous studies which applied higher concentrations and found that sublethal effects occurred at significantly lower levels than lethal effects in an acute test setting (4 days). Moreover, after parameterizing the DEB model for various temperatures, we identified a lower threshold for both lethal and sublethal effects at higher temperatures, indicating increased intrinsic sensitivity. Overall, this study contributes to future risk assessments considering temperature as a crucial factor and exemplifies the integration of the DEB model into experimental design for comprehensive toxicity evaluations.

Optimizing office building operations: a framework for continuous dynamic energy simulations in decision-making for efficiency

Optimizing office building operations: a framework for continuous dynamic energy simulations in decision-making for efficiency

A simple testing-analysis method to evaluate the mechanical characteristics of soils under cyclic loading

ABSTRACT This study presents a simple, yet robust testing methodology employed for investigating the mechanical behaviour of soils under cyclic loading conditions. Small cylindrical specimens of soil (10.5 mm diameter and 35.0 mm high) were subjected to oscillatory torsional loading in either strain sweep or stress sweep mode using the dynamic shear rheometer. Key mechanical properties, including dynamic shear modulus, phase angle, and energy dissipation capacity, were obtained and used to effectively identify threshold strain levels which differentiated the linear, nonlinear, and damage response of the soil. This study further applied the proposed method to stabilized soils to evaluate the effects of stabilizers on improving soil stiffness, while also considering their potential effects on increasing soil brittleness, which could ultimately lead to reduced resistance to fatigue cracking. The successful development of this testing protocol has the potential to evolve into a specification-type method due to its efficiency, repeatability, sensitivity, and fundamental robustness.

Marine aquaculture spatial planning on market orientation for Pacific oyster in Shandong, China

Accessing the production value is essential to the selection of suitable sites for aquaculture farms. This study employed a Dynamic Energy Budget (DEB) model and used market-oriented indicators, including shell length, flesh weight, condition index and minimum farming duration, to analyze the suitability for Pacific oyster aquaculture in offshore Shandong, China. Chlorophyll a (Chl-a) concentration, Total Suspended Sediment (TSS) concentration, and Sea Surface Temperature (SST) were extracted by remote sensing and used as forcing variables in the bioenergetic model. Four market-oriented indicators and five zones in the study area were chosen to develop a Suitable Market-Aquaculture site-selection model (SMASM) and estimate the oyster farming suitability. The results demonstrated that Sanggou Bay exhibits high potential for Pacific oyster year-round aquaculture. Eastern Laizhou Bay is suitable for the autumn-spring fattening culture of adult oysters. Laoshan Bay and Changshan Islands are suitable for promoting rapid growth in juvenile oysters. The results of our model were consistent with the oyster production value in Shandong, showing an overall increasing trend except for the anomalous value observed in 2019. Sudden drops in water temperature, red tides, and significant increases in turbidity can exert detrimental effects on oyster production, which has been evidenced to be influenced by Super Typhoon Lekima in 2019. Although this study concentrated on a specific geographical region, the model could be applied to other regions to develop market-oriented suitability management for species and environments worldwide.

Dynamic compressive behavior of functionally graded triply periodic minimal surface cellular structures

The Triply Periodic Minimal Surface (TPMS) structure is regarded as a porous structure used for impact protection due to its lightweight, high strength, and high specific energy absorption (SEA). This paper investigates the dynamic mechanical properties of the TPMS structure by Split Hopkinson Bar (SHPB) experiments and finite element analysis (FEA). We compare stress peak, SEA, strain rate effect, and deformation pattern for functionally graded Primitive (P), uniform P, and uniform Gyroid (G) structures. It is found that the increasing magnitude of peak stress in the TPMS structures becomes more evident under high-impact loads. As the relative density increases, the strain rate effect becomes more prominent. The uniform G structures exhibit higher plateau stress and SEA than uniform P structures. Besides, graded P structures exhibit a climbing phenomenon compared to uniform P structures in the platform section. The FEA results also demonstrate that higher SEA and plateau stresses are exhibited in the graded P structure. The graded design minimizes the strain rate effect compared to the corresponding uniform structures. It is essential to set a properly graded index to enhance the dynamic energy absorption capacity of the TPMS structure, as more fluctuations occur when the graded index increases.

Synergistic effect of microfibers and oriented steel fibers on mechanical properties of UHPC

The study introduces a novel approach to enhance the properties of Ultra-High Performance Concrete (UHPC) through multi-scale synergistic reinforcement using microfibers (0.66 mm) and oriented steel fibers (13 mm). Various aspects were investigated, including rheological properties, fiber orientation, and fiber pull-out characteristics. Besides, quasi-static mechanical properties and dynamic compressive properties of UHPC were tested and the bending failure was monitored by acoustic emission technique. Experimental results showed that microfiber improved mechanical properties of UHPC matrix and enhanced the fiber-matrix interface. Compressive strength, flexural strength, and toughness of specimens were increased by as high as 25 %, 78 %, and 55 %, respectively, when microfiber was mixed with oriented steel fibers. In terms of dynamic impact performance, UHPC exhibited significant strain rate sensitivity, and microfibers blended with oriented steel fibers resulted in complete damage pattern when subjected to impact loading, and dynamic compressive strength and energy absorption increased by 48.5 % and 54.8 %, respectively. Therefore, oriented steel fibers coupled with microfibers provide an effective method to enhance the mechanical performance of UHPC.

Dynamic modeling and energy demand analysis of chain heavy load transfer system on marine mobile platform

ABSTRACT The demand for transferring the heavy load on marine mobile platform is steadily increasing, surpassing the capabilities of the current system. This paper introduces a chain heavy load transfer system and develops its dynamic model. This paper studies the sensitivity laws of the system’s energy demand to unknown parameters and proposes an adaptive mutation particle swarm optimization (AMPSO), whose identification accuracy is verified through comparative analysis. Experimental verification confirms the reliability of the system model while studying the influence of environmental loads on the system’s energy demand. The results demonstrate that the chain transfer system meets the requirements of marine mobile platforms, and the system model incorporates the primary influencing factors. Unknown parameters significantly influence the system’s energy demand, and the displacement error after parameter identification using AMPSO is 0.00056 rad, substantially enhancing the accuracy of model calculations. The model calculations of the system closely align with experimental measurements, with a maximum displacement error not exceeding 0.004 rad. Sway exerts a greater influence on the system’s energy demand compared to tilt. When tilt and sway are superimposed, the friction torque between the load and the track results in increased input torque and power for the vertical arrangement of the system, with a maximum torque of 328.6kN·m and maximum power of 400 kW.

Enhanced Hybrid Routing Protocol for Energy-Efficient Multipath Routing in Manets

Mobile Ad Hoc Networks (MANETs) pose challenges in managing dynamic energy consumption and optimizing network lifetime. This study proposes an improved hybrid routing protocol by integrating situation-adaptive routing and energy-efficient multipath routing strategies. We identified two promising routing protocols, FF-AOMDV and STFDR. While FF-AOMDV minimizes energy consumption, it ignores loss of power, resulting in link failures and reduced MANET lifetime. To address this, we introduce PLA-AOMDV, which efficiently manages power loss and outperforms FF-AOMDV in experimental results. However, PLA-AOMDV needs enhancements in addressing link breakage and utilization. Thus, we propose ELA-AOMDV to maximize energy efficiency and load balancing, refining route selection for better outcomes. Experimental findings demonstrate ELA-AOMDV's superiority over PLA-AOMDV in throughput, packet dropping rate, energy consumption, and network lifetime. Additionally, we present an Improved Hybrid Routing Protocol (IHRP), which combines DMR, AOMDV, OLSR, and AODV. Leveraging the strengths of these protocols, IHRP exhibits superior performance compared to AOMDV, ZRP, AODV, and OLSR. It proposed enhanced hybrid routing protocol effectively addresses the challenges of dynamic energy consumption and efficient multipath routing in MANETs, improving network performance and lifetime.