Suitable Configuration Research Articles

Multi-objective design of off-grid low-enthalpy geothermal generation systems considering partial-load operations

This work addresses the multi-objective design of an organic Rankine cycle system for low-enthalpy applications. The design is generated from end-user demand variations. The model uses the reference equations of state of four working fluids commonly used in the literature: R1234yf, R1234ze (E), R134a and R245fa. This approach allows computing the optimal sizing of each unit of the equipment that composes the cycle, obtaining a suitable configuration for each working fluid. That is, the comparison between configurations is linked to the thermodynamic properties of the fluid. In addition, it addresses the phase changes present in each operation and the operational adjustments associated with changes in demand. Therefore, the optimal design captures partial load operation through a multi-period model. Given the off-grid operating conditions, the effects of coupling with energy storage systems are analyzed. The considered objective functions are the total annual cost and energy efficiency of the system. Results indicate that the sizing of the heat exchangers is significantly affected by phase change effects and that the R1234yf and R1234ze (E) fluids are promising since their thermodynamic properties allow for trade-offs between the economic and energy performance of the system. System efficiencies, considering part-load operation and demand variability, can be increased by up to 2 % with the inclusion of energy storage, significantly improving economic performance and reducing costs by up to 10 %.

Performance analysis of a novel façade-based building integrated photovoltaic-thermal system with phase change material for domestic hot water

Since the current contribution of solar thermal energy to the amount of energy consumed for domestic hot water in buildings worldwide is very low (8.4 %, approximately), the potential of this renewable energy to meet the demand for domestic hot water is quite significant. In this context, this paper presents a new façade-based building integrated photovoltaic-thermal system with phase change material which has been patented recently. It is a modular device for installation on façades and roofs, enabling the production of domestic hot water and electricity using solar energy. The main novelty of the system lies in the use of a photovoltaic glass sheet, which improves the building’s aesthetics and facilitates the architectural integration of this type of devices. Thus, a photovoltaic glass is used for the production of electricity, a phase change material for heat storage and a water-phase change material exchanger for the production of domestic hot water. The design and verification stages of the system were developed for a case study under typical usage conditions. Two dimensional numerical models of five different configurations (of the energy harvesting and storage module and two dimensional and three dimensional numerical models of the finned exchanger were carried out to simulate the charge and discharge processes. The most suitable configuration of the system, characterised by a 12 mm vacuum gap and a low emissivity of the absorber, was able to meet the requirements in terms of water flow rate and supply temperature (45 °C) for a shower time of 5 min.

A Convolutional Neural Network-Based Auto-Segmentation Pipeline for Breast Cancer Imaging

Medical imaging is crucial for the detection and diagnosis of breast cancer. Artificial intelligence and computer vision have rapidly become popular in medical image analyses thanks to technological advancements. To improve the effectiveness and efficiency of medical diagnosis and treatment, significant efforts have been made in the literature on medical image processing, segmentation, volumetric analysis, and prediction. This paper is interested in the development of a prediction pipeline for breast cancer studies based on 3D computed tomography (CT) scans. Several algorithms were designed and integrated to classify the suitability of the CT slices. The selected slices from patients were then further processed in the pipeline. This was followed by data generalization and volume segmentation to reduce the computation complexity. The selected input data were fed into a 3D U-Net architecture in the pipeline for analysis and volumetric predictions of cancer tumors. Three types of U-Net models were designed and compared. The experimental results show that Model 1 of U-Net obtained the highest accuracy at 91.44% with the highest memory usage; Model 2 had the lowest memory usage with the lowest accuracy at 85.18%; and Model 3 achieved a balanced performance in accuracy and memory usage, which is a more suitable configuration for the developed pipeline.

On the intricacies of soot volume fraction measurements in counterflow diffusion flames with light extinction: Effects of curtain flow

Counterflow diffusion flame is an attractive platform for fundamental research on kinetics of soot formation. Accurate determination of soot volume fraction in the flame is a prerequisite for in-depth analysis of the sooting characteristics and assessment of predictive soot models. Light extinction has been proven to be an efficient technique for measuring soot volume fraction thanks to its non-intrusiveness and its simple optical setup. Nevertheless, tomographic inversion needs to be performed if spatially resolved soot volume fraction is to be obtained from the measured light extinction data which is essentially a projection along the line-of-sight. In this regard, radial distribution of soot volume fraction would affect the accuracy of the measurement through its influences on the inversion processes. In this work, we show that the curtain flow, which is necessary to avoid the formation of the undesired secondary diffusion flame and to keep the core counterflow from ambient disturbances, has notable effects on spatially resolved soot volume fraction measurements with line-of-sight measurements. In particular, different flow rate settings of the curtain flow can result in different soot distributions at the edges of soot fields: upwards curved, outwards extended, and downwards curved, which may influence the measurement of centerline soot volume fraction distribution. The necessity of tomographic inversion, the minimal region of the projection image necessary for tomographic inversion (when necessary), the quasi-one-dimensional feature of soot distribution, and the sensitivity of measurement to slight flame asymmetry were investigated where possible to determine the most suitable curtain flow configuration for soot volume fraction measurements by light extinction. Recommendations on curtain flow setting are finally made.

Experimental and Numerical Investigation of Cylindrical and Shaped Cooling Holes With Forward and Reverse Injection

The present work proposes a suitable injection hole configuration of cylinder and laidback fan-shaped with forward and reverse direction for film cooling of a gas turbine blades application, based on experimental and numerical analysis. The experimental study is conducted for cylindrical hole at blowing ratio (1), injection angle (35°), and density ratio (1.2). The numerical study is performed for a wide range of operating parameters such as blowing ratios on (1-3), density ratios (2.42), mainstream flow Reynolds number as 4000 based on the hydraulic diameter of wind tunnel channel and, injection angle (35°) with the effect of forward and reverse injection of laidback fan shaped. The present study reveals that the formation of kidney vortices mitigated for reverse-shaped holes (secondary air is injected such that its axial velocity component is in the reverse direction to that of the mainstream) results in higher cooling performance with respect to forward-shaped holes. The coolant coverage is likewise more consistent and higher in the lateral direction compared to the forward injection.

Designable Synthesis of Layered Silicates and Tunable Interlayer Expanded to Zeolites.

Layered zeolitic silicates and corresponding interlayer-expanded porous materials exhibit attractive application potential in wide fields. Nonetheless, designable synthesis and structure analysis of layered silicates remain challenging. Herein, two kinds of layered silicates are synthesized using different di-quaternary ammonium-type organic structure-directing agents (OSDAs). Their crystal structures are analyzed and verified by 3D electron diffraction (3D ED) and high-resolution TEM imaging. The suitable configurations of OSDA can lead to desirable interlayer states. Additionally, two new zeolite structures both with 12-membered ring (MR) channels intersected by 8 MR channels and larger interlayer spaces are constructed from layered silicate precursors by interlayer silylation. The new zeolitic material exhibits potential application in adsorption of organic pollution and catalytic reaction. This study is expected to develop versatile ways for the design and synthesis of layered silicates even zeolites and provide references in characterizing layered materials and zeolites as well.

A lower bound for the complex flow number of a graph: A geometric approach

AbstractLet be a real number. A complex nowhere‐zero ‐flow on a graph is an orientation of together with an assignment such that, for all , the Euclidean norm of the complex number lies in the interval and, for every vertex, the incoming flow is equal to the outgoing flow. The complex flow number of a bridgeless graph , denoted by , is the minimum of the real numbers such that admits a complex nowhere‐zero ‐flow. The exact computation of seems to be a hard task even for very small and symmetric graphs. In particular, the exact value of is known only for families of graphs where a lower bound can be trivially proved. Here, we use geometric and combinatorial arguments to give a nontrivial lower bound for in terms of the odd‐girth of a cubic graph (i.e., the length of a shortest odd cycle) and we show that this lower bound is tight. This result relies on the exact computation of the complex flow number of the wheel graph . In particular, we show that for every odd , the value of arises from one of three suitable configurations of points in the complex plane according to the congruence of modulo 6.

A hybrid method to solve reliability-cost-oriented bi-objective machine configuration problem for a flow shop system

Machine configuration is a crucial strategic decision in designing a flow shop system (FSS) and directly affects its performance. This involves selecting device suppliers and determining the number of machines to be configured. This study addresses a bi-objective optimization problem for an FSS that considers repair actions and aims to determine the most suitable machine configuration that balances the production reliability and purchase cost. A nondominated sorting genetic algorithm II (NSGA-II) is used to determine all the Pareto solutions. The technique for order preference by similarity to an ideal solution is then used to identify a compromise alternative. It is necessary to assess the production reliability of any machine configuration identified by the NSGA-II. The FSS under the machine configuration is modeled as a multistate flow shop network, and Absorbing Markov Chain and Recursive Sum of Disjoint Products are integrated into the NSGA-II for reliability evaluation. The experimental results of solar cell manufacturing demonstrate the applicability of the proposed hybrid method and validate the efficiency of the NSGA-II compared with an improved strength Pareto evolutionary algorithm.

DC Switchyard Configurations for the Integration of Distributed Energy Resources

HVDC supergrid must grow in an organized way. The objective of HVDC substations will be to integrate generation groups and occasionally connect them to the AC network. That way, all substations will not be identical and their relevance will not be the same. In AC substations, network topological changes are made to limit the short circuit current contributions, perform load distributions and allow maintenance work when the application of restrictions is necessary, without compromising generation. These maintenance tasks should allow the exploitation of the network without making concessions on the stability of the system. DC networks do not require topological changes in the network to distribute loads, its utility would be reduced to facilitate maintenance tasks and minimize the possible effects of faults. However, it must be discussed which is the most suitable switchyard or whether more than one switchyard are required such as in AC networks. In the paper the usual topologies and switchyard configurations are analyzed and compared to determine if the architectures inherited from the AC grids can be used in the future HVDC supergrid. Several DC switchyard configurations are also discussed. Finally, the most suitable configurations are compared and applied to a study case.

Analysis of the current status and development prospects of artificial hearts

Confronted with the rapid need for transplantable hearts, patients who need a heart transplant cannot receive the suitable configuration. Thus contributes to the development of artificial hearts, which can be created to substitute the old, the ill heart without waiting for transplantable hearts. Nowadays, this paper shows the public the artificial hearts. Through the extensive literature, it is clear that the development of artificial hearts. Dating back to the fifties of the last century, scientists began studying artificial hearts. Till now, China has created four generations of artificial hearts. They became more and more strong. The importance of the heart goes without saying, however, every year there are more and more heart failure patients. Paying more attention to the artificial hearts helps reduce the death rate of heart failures. Actually, although the patients can get the heart donors, they may not tolerate rejection. So research into artificial hearts more suitable for patients is imminent. This paper mainly introduces the fourth-generation artificial hearts (in fact, it is an improved version of the third generation), the magnetic levitation artificial heart attracts much more attention, and its composition and function have been greatly improved, reducing the difficulty of surgery. It is hoped that people can know much more about artificial hearts, and prospects for better methods to make better artificial hearts, and promote heart transplantations.

Mn(III) O^N^O Complexes as Water-tolerant and Environmentally Benign Catalysts for Polyurethane Foam Synthesis.

Polyurethanes are synthesized on industrial scale by the reaction of diisocyanates with diols in the presence of catalysts which are commonly based on tin complexes and amines. However, due to the toxicity and volatility of these tin catalysts and amines, there is the need to develop new catalysts that are more environmentally benign. Herein, we report the synthesis of O^N^O pincer-ligated Mn(III) and Fe(III) complexes that serve as suitable catalysts for urethane formation and are stable to hydrolysis as predicted by computations and observed experimentally. The O^N^O pincer scaffold is vital to the activity of these catalysts, simultaneously ensuring increased solubility in the reaction medium as well as providing a stable framework upon dissociation of co-ligands in the catalytic cycle. In silico mechanistic investigations for urethane formation show that the stabilization of active species in square-planar geometries enabled by these O^N^O ligands permit the simultaneous coordination of alcohol and isocyanate in suitable configuration at the metal center.

Rapid Decision-Making Tool for Electric Powertrain Sizing for Motorcycles during New Product Development

As part of the intergovernmental and public interventions to reduce carbon dioxide emissions, there are no existing regulations to ban the sale of petrol motorcycles (PM), but it is expected that motorcycle regulations will follow car regulations with several years of delay. There is an emerging trend in motorcycle uptake, which will lead to new development projects with existing brands, and new brands, and will clearly increase the need for development tools that satisfies design challenges specific to electric motorcycles (EM) and electric powertrains. There is significant importance in motorcycle design to quantify the vehicle-level performance indicators and specifications, which are not limited to total vehicle mass, range, acceleration performance, and top speed. Those performance indicators should be quantified for different powertrain configurations and component selections to identify the most suitable configuration for the specific motorcycle development. In this paper, an innovative powertrain sizing approach is proposed to provide solutions for EMs against the design challenges specific to electric motorcycles. The innovative approach is to apply the practice of design space exploration (DSE) in resilient system design (RSD) to EM development. As a proof of concept, a case study of battery sizing is presented, in which a powertrain sizing tool is used to identify battery pack sizing requirements using requirement-based design (RBD), sensitivity analysis and DSE. The case study shows that the RBD approach allows EM product developers to identify a single solution, while DSE clearly demonstrates the trade-off between different configurations, taking multiple design variables into account. The tool prioritises high accessibility and high confidence with limited information at the early phases of electric motorcycle powertrain component sizing and selection.

Assessing Feed-Forward Backpropagation Artificial Neural Networks for Strain-Rate-Sensitive Mechanical Modeling.

The manufacturing processes and design of metal and alloy products can be performed over a wide range of strain rates and temperatures. To design and optimize these processes using computational mechanics tools, the selection and calibration of the constitutive models is critical. In the case of hazardous and explosive impact loads, it is not always possible to test material properties. For this purpose, this paper assesses the efficiency and the accuracy of different architectures of ANNs for the identification of the Johnson-Cook material model parameters. The implemented computational tool of an ANN-based parameter identification strategy provides adequate results in a range of strain rates required for general manufacturing and product design applications. Four ANN architectures are studied to find the most suitable configuration for a reduced amount of experimental data, particularly for cases where high-impact testing is constrained. The different ANN structures are evaluated based on the model's predictive capability, revealing that the perceptron-based network of 66 inputs and one hidden layer of 30 neurons provides the highest prediction accuracy of the effective flow stress-strain behavior of Ti64 alloy and three virtual materials.

The study of numerical simulation and texture of soybean protein based on high moisture extrusion with different screw elements

Extrusion conditions and suitable screw configuration are key factors that affect protein reactivity and thus the properties of the blend. Fully revealing the whole extrusion process using numerical simulation is still a strong challenge due to the complexity of the flow field. In this paper, the flow behavior of protein under the action of kneading block and kneading block-reversing element was further revealed through the equivalent substitution, and the quality attribute of the extruded protein was also investigated. The results demonstrated the fluid pressure inside the barrel presented as a stepped and jagged increasing trend, and higher temperature and lower viscosity can be obtained at the screw root. The outlet pressure loss decreased when kneading block approached the outlet. Since the more complex fluid flow state at the location of the reversing element, more mechanical energy is transformed into internal energy, which amplifies the effect of temperature rise. Compared to the kneading block, the introduction of a reversing element can effectively improve the hardness and texturization of the extruded product, increase the brightness of color, and a better performance can be obtained at the backward reversing element. Overall, the consistency between the numerical simulation and the experimental results provided a research basis for the optimization of screw design combinations, and new theoretical support for the subsequent processing of meat analogs.

A multi-objective optimization workflow of ring-rolling process parameters based on production energy and time

Our industrial era is characterized by a significant attention to environmental aspects and production sustainability. Under this point of view, the minimization of the process energy represents a milestone leading to a consistent reduction of pollution. However, to promptly react to the high production rate market request, companies employ time saving manufacturing strategies, often in contrast with this principle. Considering this, an optimization concerning the reduction of both production time and energy, results to be strategical, especially when energy-intensive processes, such as ring rolling, are considered. Ring rolling is a shaping process performed by a dedicated equipment, composed of a driving roll, an idle roll, and a couple of axial rolls, allowing to obtain seamless rings while simultaneously reducing their height and thickness, while enlarging diameter. The kinematics of each component of the equipment can be set independently. This leads to several process conditions influencing quality, energy, and times, and makes it difficult the selection of the most suitable configuration. In this paper, a multi-objective optimization workflow is presented. Starting from validated FEM simulation campaign results, the proposed methodology allowed to individuate the best process parameters combination for limiting energy and time, encouraging its application to a wider range of energy-consuming processes.

Optimizing separate and combined grids for cost-effective hybrid renewable energy electrification in Mogadishu, Somalia

Expanding access to affordable, reliable, and sustainable electricity is an urgent priority in Somalia, which suffers from high energy costs and climate vulnerability despite negligible emissions. Therefore, this study employs MATLAB simulation software and three algorithms—particle swarm optimization (PSO), genetic algorithm, and simulated annealing—to determine optimal separate and combined grid designs for a hybrid renewable energy system in Mogadishu, Somalia. Four system configurations are assessed, namely, utilities—diesel-alone, Photovoltaic (PV)–diesel hybrid, wind–diesel hybrid, and PV–wind–diesel hybrid across the grids of three utilities—Benadir Electric Company, Mogadishu Power Supply, and Blue-Sky Energy. The algorithms evaluate technical feasibility, economic viability, and system reliability to identify the most suitable configurations. Forty-eight systems are analyzed. The combined PV/wind/diesel grid optimized with PSO is most effective, reducing the net present cost by 32%–47% and levelized cost of electricity by 41%–60% compared to diesel-only systems while maintaining reliability. Greenhouse gas emissions decrease by 38%–59% with the hybrid system.

Novel Synthesis of Generalized Strongly Coupled Resonator Triplet Filters With Complex Reflection Zeros

Complex reflection zeros (CRZs) are introduced into generalized strongly coupled resonator triplet (GSCRT) filter synthesis for the first time to reliably eliminate negative couplings, thus facilitating physical implementation. CRZs bring more flexibility in synthesis and can be preassigned and regulated as needed to guarantee nonnegative couplings in different topologies and achieve varying electrical performance. Besides, CRZs bring the advantage of self-suppressed spikes, which can save extra band-stop modules in the system. To provide useful guidelines for designers, the selection of suitable CRZs is discussed in detail. With the introduced CRZs, the responses of GSCRT filters feature nonideal “in-between” performance, which shows a tradeoff between electrical performance and physical realization. Also, a comparison between the performance of GSCRT filters, extracted-zero, and path filters is given, which aims to help designers choose the most suitable configuration in practical use. Finally, the good measurement results of an anti-interference satellite filter have strongly validated the proposed theories.

Towards Efficient Energy Solutions: MCDA-Driven Selection of Hybrid Renewable Energy Systems

In these days of growing awareness on Renewable Energy Sources and their benefits, there is a major issue that needs to be considered, which is selection of suitable Hybrid Renewable Energy System (HRES) among the vast multitude of choices. In this paper, multiple Multi Criteria Decision Analysis (MCDA) techniques are proposed to select the best among a choice of six HRES Systems using different criteria including but not limited to net present cost (NPC), operating cost, renewability fraction, CO2 & NOx emissions etc. The criteria weights are obtained using Analytical Hierarchy Process (AHP) based on the preference order of the criteria. The decision matrix is obtained from the statistical data of the different HRES and using different MCDA techniques such as Multi-Objective Optimization on the Basis of Ratio Analysis (MOORA), Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR), rankings are given to the HRES systems based on their closeness to the ideal solution. These rankings are helpful in the selection of suitable HRES configuration for normal household purposes. Since cost aspects are given greater preference, the obtained rankings lean more towards economically affordable solutions without compromising on the number of units generated.

Design of a computational method to optimise acoustic output of the human vocal tract

The influence of the geometric configuration of the human vocal tract (HVT) on the character of acoustic energy distribution during phonation of the vowel [a:] has been analysed. The computationally efficient mathematic models of the HVT have been assembled based on super elements and an isoparametric element with higher degree of polynomial shape function. The assembled models enable the easy and quick geometrical reconfiguration of the HVT and they can be used for the time-consuming optimization process with aim to find the suitable geometric configuration of the HVT to generated the so-called singer’s formant.

Flexural-gravity wave scattering by an array of bottom-standing partial porous barriers in the framework of Bragg resonance and blocking dynamics

Flexural-gravity wave scattering by an array of vertical porous barriers of various configurations is investigated in finite water depth from the viewpoint of blocking dynamics. A scattering matrix is introduced for the velocity potentials using the canonical eigenfunction expansion method developed for a single propagating wave mode to account for the multiple propagating wave modes. Subsequently, appropriate matching conditions are applied at the interface boundaries and edges to solve the physical problem. Apart from multiple barriers of equal length, the efficiency of four different barrier configurations of unequal lengths is investigated. This study shows that out of these four barrier configurations, the convex and increasing order of the barrier arrangements are more effective as wave-dissipating systems than the concave and decreasing order of the barriers. Bragg reflection occurs in the case of two or more barriers for a specific value of porosity and suitable barrier configuration, whose amplitude decreases with an increase in the number of barriers due to the dissipation of wave energy. The presence of three propagating wave modes in the blocking paradigm leads to mode conversion within a certain range of the frequency space. Both the scattering and dissipation coefficients are influenced by the wave energy transfer rates and the amplitudes of incident, reflected, and transmitted wave modes. This investigation exhibits the presence of discontinuities in the scattering coefficients at frequencies where blocking and mode conversion occur. The frequency domain results are used to simulate the plate displacement in the time domain by applying the Fourier transform.