Maximum Performance Efficiency Research Articles

Technical diagnostics of electrically operated valves at npp

The article discusses the possibilities of technical diagnostics of electrically operated valves at nuclear power plants in order to increase their reliability and service life, as well as to achieve maximum operation efficiency of systems in nuclear power plants.

Effect of twisted-tape inserts and nanofluid on flow field and heat transfer characteristics in a tube

In the present study, the flow and heat transfer of CuO-water nanofluid in different solid concentrations (1–4 vol%) in a tube have been simulated by using the single- and two-phase (mixture) models. The simulations have been conducted under the turbulent flow regime in different Reynolds numbers ranging from 3000 to 36,000. The effects of using CuO-water nanofluid on the Nusselt number, friction factor, and performance evaluation criterion have been investigated. It is found that employing the two-phase mixture model leads to having closer results in reality compared to the single-phase model. The results revealed that the maximum performance efficiency coefficient in the tube with one twisted tape is 2.18 (for the two-phase model, Re = 36,000 and φ = 4%), while for a tube with two twisted tapes under the same conditions, it is 2.04. Thus, the use of one twisted tape is more favorable from the thermal-fluid dynamics viewpoint.

Triboelectric micromotors actuated by ultralow frequency mechanical stimuli

A high-speed micromotor is usually actuated by a power source with high voltage and frequency. Here we report a triboelectric micromotor by coupling a micromotor and a triboelectric nanogenerator, in which the micromotor can be actuated by ultralow-frequency mechanical stimuli. The performances of the triboelectric micromotor are exhibited at various structural parameters of the micromotor, as well as at different mechanical stimuli of the triboelectric nanogenerator. With a sliding range of 50 mm at 0.1 Hz, the micromotor can start to rotate and reach over 1000 r min−1 at 0.8 Hz. The maximum operation efficiency of the triboelectric micromotor can reach 41%. Additionally, the micromotor is demonstrated in two scanning systems for information recognition. This work has realized a high-speed micromotor actuated by ultralow frequency mechanical stimuli without an external power supply, which has extended the application of triboelectric nanogenerator in micro/nano electromechanical systems, intelligent robots and autonomous driving.

Rational Behavior of an Enterprise in the Energy Market in a Circular Economy

In order to ensure their market sustainability, it is essential for energy-intensive industrial companies to address the issues of efficient energy use. Companies that are prepared to embrace tariff hikes, structural changes in fuel and energy markets, and a shortage of energy resources have a wider range of options to respond to the new challenges posed by the external environment and to reduce their risks. This task becomes particularly relevant in the context of the development of the circular economy that is aimed at resource optimization, energy conservation, zero-waste manufacturing, and business models that are based on maximum operational efficiency. This study aims to develop a methodology for rational behavior of the energy consumer in the context of the circular economy. The concept of “rational behavior” is defined by the authors as the intention to make the maximum use of the advantages and potential of energy markets in order to reduce the cost of energy supply, increase the level of electrification in industrial production, and use the capabilities of their own energy business. The article describes the main principles of rational behavior that serve as the foundation for effective implementation of various strategies (that of the seller, buyer, or both) in a company. A link is shown between rational behavior and energy market potential management in a company as a mix of technological, economic, and organizational activities performed by the energy consumer in a competitive market and effective market risk management. Forms of off-grid power supply and conditions for their application in manufacturing, for example, mini-combined heat and power (CHP) plants and quadgeneration plants at large metallurgical facilities were analyzed.

A Comparison Study of Performance Efficiency of Lead-Acid Batteries Available in the Iraqi Markets.

Batteries consider the major important devices for energy storage based on converting the chemical energy to electrical energy. Different types of batteries are available working in different efficiencies. In this work the performance efficiency of five types of batteries available in the Iraqi were assessed. Different operating variables such as Battery Type (Akko, Raggie, Aswar, Terminator, and Hongdeng), Temperature (20, 25, 35, 45, 55, and 65˚C), and Charging Time (24, 48, and 72 hr) were studied the impact of these on the performance efficiency of each battery type. According to the results obtained in this study, maximum performance efficiency achieved was 7.2 V at optimum operating variables are (temperature 20˚C), and (charging time 48 hr). Furthermore, a computer was used with Data Logger to be connected with batteries. Finally, the most stable type and resistance to operating conditions was Aswar type in the first rank and Hongdeng type in the last rank.

Incorporating managed preferences in the evaluation of public organizations efficiency: a DEA approach

Classical Data Envelopment Analysis (DEA) models have often been used to evaluate the public organizations effectiveness. However, such models, by ignoring the managers preferences, can classify as efficient organizations that, in fact, are not. Based on this motivation, the objective of this paper was to evaluate, through a DEA model that incorporates managerial preferences, the efficiency of the 25 superintendencies of the National Department of Mineral Production (DNPM), an autarchy linked to the Ministry of Mines and Energy. For this purpose, the number of servers in the middle and end areas and, as outputs, the number of mining titles granted in 2016 was considered as input. Manager preferences regarding outputs were incorporated into classical DEA models using the assurance region method. The results showed that when management preferences were incorporated into classic DEA models, the DNPM superintendencies number that showed maximum operational efficiency was reduced from eight to five. For superintendencies classified as inefficient, the benchmarks and performance targets were identified, which is useful, since they can support the action planning aimed at reducing the high liabilities pending processes for analysis by the municipality. This would reduce DNPM's slowness in granting mining bonds, which would stimulate investments in the mineral sector, which is of paramount importance to the Brazilian economy. It should be emphasized that the methods used in this research can be applied in the evaluation of the organizations efficiency whose managers have different preferences on inputs and outputs.

How Amazon’s delivery logistics redefined retail supply chains

Amazon is setting very high standards for the entire retail industry with the market-leading ecommerce innovations they are implementing across their delivery logistics infrastructure, as well as the technologies behind it. As customer spend rapidly shifted over the past decade towards online commerce and away from physical stores, customer expectations around convenience, choice and speed of delivery have also changed drastically. The boom of on-demand technologies such as real-time tracking, alongside the widespread adoption of smartphones, means that retailers across the world need to quickly adapt in order to stay relevant with their customers. The implications of this shift towards customer-centric deliveries affect the entire retail supply chain, which needs to be redesigned to ensure companies gain maximum operational efficiency while providing an exceptional customer experience. This new retail landscape is having a huge impact on both the micro and the macro level. On the one hand, retailers need to optimise their fleets, delivery partners, warehouses, stores and customer service. On the other hand, regulators need help creating cities that provide the optimal infrastructure to efficiently manage the flow of goods. The last mile in particular is becoming one of the toughest challenges for retailers to support, and they will need to embrace technology that helps them manage their operations while maintaining a healthy bottom line. It is not a simple task to reach all customers wherever they are, whenever they want — especially in countries or cities with low population density. However, as delivery companies, in-house fleets and crowdsourced resources become more aware of these challenges, we will see the emergence of new models that efficiently utilise multiple tools, technologies and resources. The entire industry is working towards achieving flawless orchestration of a fully-transparent, fully-optimised supply chain, which is driven as much by cost-efficiency as it is by providing end-customers with exceptional brand experiences.

Determining electrical losses of the traction drive of electric train based on a synchronous motor with excitation from permanent magnets

We have studied a traction drive based on the synchronous motor with excitation from permanent magnets for its electrical losses. A simulation model of the traction drive is synthesized, which employs the algorithm of a space-vector PWM. A special feature of the model is the application of parameters of actual IGBT-transistors and the possibility for obtaining instantaneous values of electric losses in transistors and snubbers of the inverter under different modes of operation. We have devised a procedure for calculating electric losses in the traction engine based on the shape of phase currents, geometrical and electrical parameters of the engine. Simulation of the traction drive and calculation of losses in the traction engine is integrated, which makes it possible to account for the impact of the inverter and engine on each other. We have simulated work of the reducer-free traction drive based on a synchronous motor with excitation from permanent magnets with a capacity of 80 kW. The dependences were constructed for losses in the traction inverter and engine on the clock frequency of a space-vector PWM and motion speed. The proposed procedure makes it possible to quantify the magnitude of electric losses in the traction drive elements depending on the types of transistors applied, clock frequency of the inverter, and parameters of the engine. This enables the optimization of the traction drive for the criterion of maximum performance efficiency, as well as thermal calculation of the elements of the drive.

An Investigation Concerning the Effect of Canal width Contraction that May be Needed in the Location of Constructing Some Irrigation Works

AbstractThe compatibility between the needed structural designed dimensions of the irrigation works and the dimensions of the water stream or the canal in which the irrigation work will be located has a great importance from more than one point of view. As it is well known, the main aim of the designer of such works is to reach the optimum design for maximum performance efficiency with economical cost, and minimize negative technical impacts that may be harmful to the safety of the whole work. Since the complete suitability between the obtained designed dimensions of the different construction elements of the work, and the original properties and dimensions of the canal in which the work will be constructed, is rarely occurring. The designer always has to make some changes in the original engineering properties and dimensions of canals, such as bed width, bed level, and/or inside side slope, to reach the needed suitable compatibility between the structural design and the natural original canal cross section. For the economical purposes, the design always needs less width of the work, than the width of the bed of the original stream cross section, so a contraction may be needed where the work will be constructed; the literature indicated that, such a contraction must not be less than 0.6 of the original bed width. That contraction, of course, has a direct impact on the different hydraulic parameters, such as water depth, velocity, and flow regime in the location of the work. Changes of such hydraulic parameters may exceed their safe permissible values, and so the whole structure may face some dangerous situations, which must be overcome. In this paper, we present a technical survey of the previous research concerning canal width contraction, with the needed technical comments, and comparisons as a logical approach for a master-thesis under the same title.

The research on direct-drive wave energy conversion system and performance optimization

A direct-drive wave energy conversion system based on a three-phase permanent magnet tubular linear generator (PMTLG) and a heaving buoy is proposed to convert wave energy into electrical energy. Sufficient experimental methods are adopted to compare the computer simulations, the validity of which is verified by the experiment results from a wave tank laboratory. In the experiment, the motion curves of heaving buoy are with small fluctuations, mainly caused by the PMTLG’s detent force. For the reduction of these small fluctuations and a maximum operational efficiency of the direct-drive wave energy conversion system, the PMTLG’s detent force minimization technique and the heaving buoy optimization will be discussed. It is discovered that the operational efficiency of the direct-drive wave energy conversion system increases dramatically after optimization. The experiment and optimization results will provide useful reference for the future research on ocean wave energy conversion system.

Influence from the rotating speed of the windward axial fans on the performance of an air-cooled power plant

The performance of the fan array in the air-cooled steam condensers (ACSCs), which consumes a large amount of the power from the generator, always affects the characteristics of the whole power plant under the effect of the meteorological conditions. As a result, it is significant to optimize the fan mode to obtain a maximum operation efficiency of the air-cooled thermal system. In the paper, a 2 × 600 MW power plant is modeled to investigate the influence from the fan rotating speed on the performance of the fan array as well as the whole air-cooled power plants. It is found that the promotion of the fan rotating speed of the windward fans improves the performance of the fan array and the heat transfer characteristics of the exchangers in the air-cooled steam condenser, and the beneficial net power in consideration of the fan consumption is also raised effectively with an improved thermal efficiency of the closed Rankine cycle.

A Bi‐Level Model for Planning Signalized and Uninterrupted Flow Intersections in an Evacuation Network

Abstract: The problem to be addressed in this paper is the lack of an advanced model in the literature to locate the optimal set of intersections in the evacuation network for implementing uninterrupted flow and signal control strategies, respectively, which can yield the maximum evacuation operational efficiency and the best use of available budgets. An optimization model, proposed in response to such needs, contributes to addressing the following critical questions that have long challenged transportation authorities during emergency planning, namely: given the topology of an evacuation network, evacuation demand distribution, and a limited budget, (1) how many intersections should be implemented with the signals and uninterrupted flow strategies; (2) what are their most appropriate locations; and (3) how should turning restriction plans be properly designed for those uninterrupted flow intersections? The proposed model features a bi‐level framework. The upper level determines the best locations for uninterrupted flow and signalized intersections as well as the corresponding turning restriction plans by minimizing the total evacuation time, while the lower level handles routing assignments of evacuation traffic based on the stochastic user equilibrium (SUE) principle. The proposed model is solved by a genetic algorithm (GA) ‐based heuristic. Extensive analyses under various evacuation demand and budget levels have indicated that the location selection of uninterrupted flow and signalized intersections plays a key role in emergency traffic management. The proposed model substantially outperforms existing practices in prioritizing limited resources to the most appropriate control points by significantly reducing the total evacuation time (up to 39%).

Assembling, Visualizing and Improving DNA Motors using Single Molecule Fluorescence

A major obstacle in developing and improving complex DNA-machines, such as motors and robots, is the difficulty of characterizing the integrity, structural dynamics and function of the assembly intermediates and of the final product. Typically, non in-situ Gel and AFM and in-situ bulk fluorescence methods are used, but these methods often failed to provide detailed structural dynamic information sufficient for device rational improvements. We will present two different DNA-motors studied using single-molecule fluorescence techniques. One motor is made of DNA-track embedded in a DNA-origami on which bipedal DNA-walker is striding upon interacting with fuel/anti-fuel, while the second motor is design to adapt autonomous behavior. The single-molecule FRET method provides detailed information about the motors structure, and the ALEX, provides information about the motor integrity and helps cleaning the data, monitors the motor assembly process and demonstrates activity in real time. The binding rate of different fuel/anti-fuel type and sequence and the efficiency of their individual steps are compared to achieve maximum operation efficiency, speed, and reliability. The detailed structural dynamic information extracted allows deeper theoretical understanding of the system behavior, and as a consequence, leading to motor improvement.

Impact of Engine Idling on Fuel Use and CO2 Emissions of Nonroad Diesel Construction Equipment

It is difficult to quantitatively assess the impact of engine idling on fuel use and emissions of construction equipment because of a lack of sufficient data. This paper presents a methodology for evaluating the impact of idling on fuel use and carbon dioxide ( CO2 ) emissions of diesel construction equipment. The results are based on field data collected from 34 items of equipment. Engine idle time may be quantified in terms of equipment operational efficiency ( η ), which is defined as the ratio of nonidle time to total equipment use time (nonidle time plus idle time). Using η and the ratio of idle to nonidle fuel use and CO2 emission rates ( r ), the percentage increase in the total quantities of fuel used and CO2 emitted ( NE ) were calculated for each item of equipment for values of η less than the maximum theoretical operational efficiency of 100%. Results showed that as η decreased (or idle time increased), NE increased. A mathematical model that uses η as a predictor variable was developed to esti...

Proposta de um método de cálculo do tempo de sedimentação no tratamento de esgotos por lodos ativados em bateladas

Neste artigo é feita uma análise do funcionamento de reatores biológicos para tratamento de esgotos pelo processo de lodos ativados, em batelada. A análise destaca o ciclo de operação desses reatores, que inclui as etapas de aeração e sedimentação, indicando o tempo de sedimentação para o qual se obtém a máxima eficiência operacional. É apresentado um método de cálculo para a determinação racional deste tempo ótimo. O trabalho contém uma revisão da literatura concernente ao assunto estudado, com ênfase nos conceitos de sedimentação zonal e fluxo de sólidos, acompanhada da dedução do método de cálculo proposto.

Cost Efficiency Benchmarking for Operational Units with Multiple Cost Drivers

We consider the activity-based costing situation, in which for each of several comparable operational units, multiple cost drivers generate a single cost pool. Our study focuses on published data from a set of property tax collection offices, called rates departments, for the London metropolitan area. We define what may be called benchmark or most efficient costs per unit of driver. A principle of maximum performance efficiency is proposed, and an approach to estimating the benchmark unit costs is derived from this principle. A validation approach for this estimation method is developed in terms of what we call normal-like-or-better performance effectiveness. Application to longitudinal data on a single unit is briefly discussed. We also consider some implications for the more routine case when costs are disaggregated to subpools associated with individual cost drivers.

Planning factors for developing an enterprise-wide picture archiving and communication system maintenance program.

Picture archiving and communication system (PACS) maintenance on an individual site basis has historically been a complex and costly challenge. With the advent of enterprise-wide PACS projects such as the Virtual Radiology Environment (VRE) project, the challenge of a maintenance program with even more complexities has presented itself. The approach of the project management team for the VRE project is not one of reactive maintenance, but one of highly proactive planning and negotiations, in hopes of capitalizing on the economies of scale of an enterprise-wide PACS maintenance program. A proactive maintenance program is one aspect of life-cycle management. As with any capital acquisition, life-cycle management may be used to manage the specific project aspects related to PACS. The purpose of an enterprise-wide warranty and maintenance life-cycle management approach is to maintain PACS at its maximum operational efficiency and utilization levels through a flexible, shared, yet symbiotic relationship between local, regional, and vendor resources. These goals include providing maximum operational performance levels on a local, regional, and enterprise basis, while maintaining acceptable costs and resource utilization levels. This goal must be achieved without negatively impacting point of care activities, regardless of changes to the clinical business environment.

Egg Production Efficiency in Dwarf Lines Selected for High and Low Body Weight as Influenced by Feed Restriction

Hens from dwarf Single Comb White Leghorn lines selected for four generations for high (H) and low (L) body weight (BW) plus randombred controls (C), sixty birds per line, were placed in cages at 18 wk of age and randomly assigned to either a full-fed (FF) or restricted-fed (R) (10 percent less than FF group) treatment. Birds received a layer ration having 16% protein and 2,816 kcal/kg metabolizable energy. Water was provided ad libitum. Individual BW and egg weights (EW) were obtained, and daily feed intake (DFI), egg production (EP), performance efficiency (PE) [egg mass (EM) per BW], and feed efficiency (FE) [EM/DFI] were calculated for 28-day periods from 18 to 41 wk of age.There were significant line, treatment, and age effects and line by age interactions for BW, EW, EM, DFI, and PE; FE was significantly influenced by age. There were significant treatment by age interactions for BW, DFI, and FE. Feed intake, BW, and EW were greatest for FFH hens and increased in all lines with age.Maximum EM occurred during 30 to 33 wk for RH and RL hens, during 34 to 37 wk for FFH, and during 38 to 41 wk for FFL. Maximum PE occurred during peak EP. Maximum FE for FFH and FFL occurred during 26 to 29 wk and during 30 to 33 wk for RH and RL. Data for C hens were intermediate to the other lines. Feed efficiency was improved by restriction for L hens from 26 to 33 wk and for H hens from 26 to 33 wk and for H hens from 26 to 41 wk of age.

Mechanical processing of mango stones

With the development of the food processing industry, large quantities of mango stones are available at factory sites. Researches have shown that the stones, hitherto considered as waste, can be processed for making such products as pickle, flour, and starch, etc. A decorticator for separating hard and fibrous outer pericarp with low nutritive value from the inner kernel was developed. Optimum operating conditions for maximum performance efficiency are suggested. It was also determined through tests that decorticating efficiency was directly proportional to the number of raspbars and speed of the cylinder. Kernel loss was directly proportional to the air-flow rate of the blower and speed of the eccentric arrangement.

RF Power Source Development for the High Current Linear Accelerator of the Spaliation Neutron Source (SNQ)

The SNQ linear accelerator design demands a rf pulse power of 267 MW at 324 MHz with 6% duty cycle, generated by 89 klystron ampflifiers, each capable of 3,5 MW of saturated peak power. Fast analog and pulse control response to achieve the required rf field stability under heavy beam loading conditions and maximum operational efficiency are major aspects of the rf system design. The advanced technique of a grid controlled klystron which is provided as rf generator accomplishes both aspects simultaneously. Test results obtained with a preliminary industrial klystron and further development steps are reported and discussed under consideration of the requirements.