Culture belief based multi-objective hybrid differential evolutionary algorithm in short term hydrothermal scheduling

International Nuclear Information System (INIS)

Zhang Huifeng; Zhou Jianzhong; Zhang Yongchuan; Lu Youlin; Wang Yongqiang

2013-01-01

Highlights: ► Culture belief is integrated into multi-objective differential evolution. ► Chaotic sequence is imported to improve evolutionary population diversity. ► The priority of convergence rate is proved in solving hydrothermal problem. ► The results show the quality and potential of proposed algorithm. - Abstract: A culture belief based multi-objective hybrid differential evolution (CB-MOHDE) is presented to solve short term hydrothermal optimal scheduling with economic emission (SHOSEE) problem. This problem is formulated for compromising thermal cost and emission issue while considering its complicated non-linear constraints with non-smooth and non-convex characteristics. The proposed algorithm integrates a modified multi-objective differential evolutionary algorithm into the computation model of culture algorithm (CA) as well as some communication protocols between population space and belief space, three knowledge structures in belief space are redefined according to these problem-solving characteristics, and in the differential evolution a chaotic factor is embedded into mutation operator for avoiding the premature convergence by enlarging the search scale when the search trajectory reaches local optima. Furthermore, a new heuristic constraint-handling technique is utilized to handle those complex equality and inequality constraints of SHOSEE problem. After the application on hydrothermal scheduling system, the efficiency and stability of the proposed CB-MOHDE is verified by its more desirable results in comparison to other method established recently, and the simulation results also reveal that CB-MOHDE can be a promising alternative for solving SHOSEE.

thermal power stations' reliability evaluation in a hydrothermal system

African Journals Online (AJOL)

Dr Obe

A quantitative tool for the evaluation of thermal power stations reliability in a hydrothermal system is presented. ... (solar power); wind (wind power) and the rest, thermal power and ... probability of a system performing its function adequately for ...

Scheduling lessons learned from the Autonomous Power System

Science.gov (United States)

Ringer, Mark J.

1992-01-01

The Autonomous Power System (APS) project at NASA LeRC is designed to demonstrate the applications of integrated intelligent diagnosis, control, and scheduling techniques to space power distribution systems. The project consists of three elements: the Autonomous Power Expert System (APEX) for Fault Diagnosis, Isolation, and Recovery (FDIR); the Autonomous Intelligent Power Scheduler (AIPS) to efficiently assign activities start times and resources; and power hardware (Brassboard) to emulate a space-based power system. The AIPS scheduler was tested within the APS system. This scheduler is able to efficiently assign available power to the requesting activities and share this information with other software agents within the APS system in order to implement the generated schedule. The AIPS scheduler is also able to cooperatively recover from fault situations by rescheduling the affected loads on the Brassboard in conjunction with the APEX FDIR system. AIPS served as a learning tool and an initial scheduling testbed for the integration of FDIR and automated scheduling systems. Many lessons were learned from the AIPS scheduler and are now being integrated into a new scheduler called SCRAP (Scheduler for Continuous Resource Allocation and Planning). This paper will service three purposes: an overview of the AIPS implementation, lessons learned from the AIPS scheduler, and a brief section on how these lessons are being applied to the new SCRAP scheduler.

An extended NSGA-III for solution multi-objective hydro-thermal-wind scheduling considering wind power cost

International Nuclear Information System (INIS)

Yuan, Xiaohui; Tian, Hao; Yuan, Yanbin; Huang, Yuehua; Ikram, Rana M.

2015-01-01

Highlights: • Multi-objective hydro-thermal-wind scheduling model (MO-HTWS) is establish. • The extra cost in MO-HTWS problem caused by wind uncertainty is considered. • An extended NSGA-III is proposed to solve MO-HTWS problem. • Constraint handling strategies are presented to modify infeasible solutions. • The feasibility and effectiveness of the proposed method is verified by example. - Abstract: Due to the characteristics of clean and renewable, wind power is significant to economic and environmental operation of electric power system so that it attracts more and more attention from researchers. This paper integrates wind power with hydrothermal scheduling to establish multi-objective economic emission hydro-thermal-wind scheduling problem (MO-HTWS) model with considering wind uncertain cost. To solve MO-HTWS problem with various complicated constraints, this paper extends NSGA-III by introducing the dominance relationship criterion based on constraint violation to select new generation. Moreover, the constraint handling strategy which repairs the infeasible solutions by modifying the decision variables in feasible zone according to the violation amount is proposed. Finally, a daily scheduling example of hydro-thermal-wind system is used to test the ability of NSGA-III for solving MO-HTWS problem. It is concluded from the superior quality and good distribution of the Pareto optimal solutions that, NSGA-III can offer an efficient alternative for optimizing MO-HTWS problem

Supply of geothermal power from hydrothermal sources: A study of the cost of power in 20 and 40 years

Energy Technology Data Exchange (ETDEWEB)

Petty, S. (Petty (Susan) Consulting, Solano Beach, CA (United States)); Livesay, B.J. (Livesay Consultants, Inc., Encinitas, CA (United States)); Long, W.P. (Carlin Gold Co., Inc., Grass Valley, CA (United States)); Geyer, J. (Geyer (John) and Associates, Vancouver, WA (United States))

1992-11-01

This study develops estimates for the amount of hydrothermal geothermal power that could be on line in 20 and 40 years. This study was intended to represent a snapshot'' in 20 and 40 years of the hydrothermal energy available for electric power production should a market exist for this power. This does not represent the total or maximum amount of hydrothermal power, but is instead an attempt to estimate the rate at which power could be on line constrained by the exploration, development and support infrastructure available to the geothermal industry, but not constrained by the potential market for power.

Hydrothermal optimal power flow using continuation method

International Nuclear Information System (INIS)

Raoofat, M.; Seifi, H.

2001-01-01

The problem of optimal economic operation of hydrothermal electric power systems is solved using powerful continuation method. While in conventional approach, fixed generation voltages are used to avoid convergence problems, in the algorithm, they are treated as variables so that better solutions can be obtained. The algorithm is tested for a typical 5-bus and 17-bus New Zealand networks. Its capabilities and promising results are assessed

Efficient Load Scheduling Method For Power Management

Directory of Open Access Journals (Sweden)

Vijo M Joy

2015-08-01

Full Text Available An efficient load scheduling method to meet varying power supply needs is presented in this paper. At peak load times the power generation system fails due to its instability. Traditionally we use load shedding process. In load shedding process disconnect the unnecessary and extra loads. The proposed method overcomes this problem by scheduling the load based on the requirement. Artificial neural networks are used for this optimal load scheduling process. For generate economic scheduling artificial neural network has been used because generation of power from each source is economically different. In this the total load required is the inputs of this network and the power generation from each source and power losses at the time of transmission are the output of the neural network. Training and programming of the artificial neural networks are done using MATLAB.

Combining loss and cost objectives in daily hydro-thermal economic scheduling

International Nuclear Information System (INIS)

El-Hawary, M.E.; Ravindranath, K.M.

1991-01-01

A formulation of optimal hydro-thermal power flow in electric power systems combining the minimum loss objective with the more conventional minimum fuel cost objective is considered. The implementation is based on a Newton's iterative procedure, with special initial guess and sparsity-based matrix manipulations to obtain improved convergence properties. The strategies are developed using three standard test systems. This paper discusses the question of assigning an equivalent cost to the loss objective component and compare results obtained using two proposed mechanisms. The first is based on results of conventional dispatch using Kron's loss formula and the second uses the bus incremental costs involved in the OPF solution. The effects of varying the relative weights assigned to each objective component on pertinent system variables such as active and reactive power generations as well as voltages are explored

Schedule control in Ling Ao nuclear power project

International Nuclear Information System (INIS)

Xie Ahai

2007-01-01

Ling Ao Nuclear Power Station (LANP) is first one built up by self-reliance in China with power capacity 990x2 MWe. The results of quality control, schedule control and cost control are satisfactory. The commercial operation days of Unit 1 and Unit 2 were 28th May 2002 and 8th Jan. 2003 respectively, which were 48 days and 66 days in advance of the project schedule. This paper presents the practices of self-reliance schedule control system in LANP. The paper includes 10 sections: schedule control system; targets of schedule control; schedule control at early stage of project; construction schedule; scheduling practice; Point curves; schedule control of design and procurement; a good practice of construction schedule control on site; commissioning and startup schedule; schedule control culture. Three figures are attached. The main contents of the self-reliance schedule control system are as follows: to draw up reasonable schedules and targets; to setup management mechanism and procedures; to organize powerful project management team; to establish close monitoring system; to provide timely progress reports and statistics information. Five kinds of schedule control targets are introduced, i.e. bar-chart schedule; milesones; Point curves; interface management; hydraulic test schedule of auxiliary piping loops; EMR/EMC/EESR issuance schedules. Six levels of bar-chart schedules were adopted in LANP, but the bar-chart schedules were not satisfactory for complicated erection condition on site, even using six levels of schedules. So a kind of Point curves was developed and their advantages are explained. Scheduling method of three elements: activity, duration, logic, which was adopted in LANP, is introduced. The duration of each piping activities in LANP level 2 project schedule was calculated based on the relevant working Point quantities. The analysis and adjustment of Point curves are illustrated, i.e. balance of monthly quantities; possible production in the peakload

Applying dynamic priority scheduling scheme to static systems of pinwheel task model in power-aware scheduling.

Science.gov (United States)

Seol, Ye-In; Kim, Young-Kuk

2014-01-01

Power-aware scheduling reduces CPU energy consumption in hard real-time systems through dynamic voltage scaling (DVS). In this paper, we deal with pinwheel task model which is known as static and predictable task model and could be applied to various embedded or ubiquitous systems. In pinwheel task model, each task's priority is static and its execution sequence could be predetermined. There have been many static approaches to power-aware scheduling in pinwheel task model. But, in this paper, we will show that the dynamic priority scheduling results in power-aware scheduling could be applied to pinwheel task model. This method is more effective than adopting the previous static priority scheduling methods in saving energy consumption and, for the system being still static, it is more tractable and applicable to small sized embedded or ubiquitous computing. Also, we introduce a novel power-aware scheduling algorithm which exploits all slacks under preemptive earliest-deadline first scheduling which is optimal in uniprocessor system. The dynamic priority method presented in this paper could be applied directly to static systems of pinwheel task model. The simulation results show that the proposed algorithm with the algorithmic complexity of O(n) reduces the energy consumption by 10-80% over the existing algorithms.

Sampling strategies and stopping criteria for stochastic dual dynamic programming: a case study in long-term hydrothermal scheduling

Energy Technology Data Exchange (ETDEWEB)

Homem-de-Mello, Tito [University of Illinois at Chicago, Department of Mechanical and Industrial Engineering, Chicago, IL (United States); Matos, Vitor L. de; Finardi, Erlon C. [Universidade Federal de Santa Catarina, LabPlan - Laboratorio de Planejamento de Sistemas de Energia Eletrica, Florianopolis (Brazil)

2011-03-15

The long-term hydrothermal scheduling is one of the most important problems to be solved in the power systems area. This problem aims to obtain an optimal policy, under water (energy) resources uncertainty, for hydro and thermal plants over a multi-annual planning horizon. It is natural to model the problem as a multi-stage stochastic program, a class of models for which algorithms have been developed. The original stochastic process is represented by a finite scenario tree and, because of the large number of stages, a sampling-based method such as the Stochastic Dual Dynamic Programming (SDDP) algorithm is required. The purpose of this paper is two-fold. Firstly, we study the application of two alternative sampling strategies to the standard Monte Carlo - namely, Latin hypercube sampling and randomized quasi-Monte Carlo - for the generation of scenario trees, as well as for the sampling of scenarios that is part of the SDDP algorithm. Secondly, we discuss the formulation of stopping criteria for the optimization algorithm in terms of statistical hypothesis tests, which allows us to propose an alternative criterion that is more robust than that originally proposed for the SDDP. We test these ideas on a problem associated with the whole Brazilian power system, with a three-year planning horizon. (orig.)

Scheduling of Power System Cells Integrating Stochastic Power Generation

International Nuclear Information System (INIS)

Costa, L.M.

2008-12-01

Energy supply and climate change are nowadays two of the most outstanding problems which societies have to cope with under a context of increasing energy needs. Public awareness of these problems is driving political willingness to take actions for tackling them in a swift and efficient manner. Such actions mainly focus in increasing energy efficiency, in decreasing dependence on fossil fuels, and in reducing greenhouse gas emissions. In this context, power systems are undergoing important changes in the way they are planned and managed. On the one hand, vertically integrated structures are being replaced by market structures in which power systems are un-bundled. On the other, power systems that once relied on large power generation facilities are witnessing the end of these facilities' life-cycle and, consequently, their decommissioning. The role of distributed energy resources such as wind and solar power generators is becoming increasingly important in this context. However, the large-scale integration of such type of generation presents many challenges due, for instance, to the uncertainty associated to the variability of their production. Nevertheless, advanced forecasting tools may be combined with more controllable elements such as energy storage devices, gas turbines, and controllable loads to form systems that aim to reduce the impacts that may be caused by these uncertainties. This thesis addresses the management under market conditions of these types of systems that act like independent societies and which are herewith named power system cells. From the available literature, a unified view of power system scheduling problems is also proposed as a first step for managing sets of power system cells in a multi-cell management framework. Then, methodologies for performing the optimal day-ahead scheduling of single power system cells are proposed, discussed and evaluated under both a deterministic and a stochastic framework that directly integrates the

Multi-Time Scale Coordinated Scheduling Strategy with Distributed Power Flow Controllers for Minimizing Wind Power Spillage

Directory of Open Access Journals (Sweden)

Yi Tang

2017-11-01

Full Text Available The inherent variability and randomness of large-scale wind power integration have brought great challenges to power flow control and dispatch. The distributed power flow controller (DPFC has the higher flexibility and capacity in power flow control in the system with wind generation. This paper proposes a multi-time scale coordinated scheduling model with DPFC to minimize wind power spillage. Configuration of DPFCs is initially determined by stochastic method. Afterward, two sequential procedures containing day-head and real-time scales are applied for determining maximum schedulable wind sources, optimal outputs of generating units and operation setting of DPFCs. The generating plan is obtained initially in day-ahead scheduling stage and modified in real-time scheduling model, while considering the uncertainty of wind power and fast operation of DPFC. Numerical simulation results in IEEE-RTS79 system illustrate that wind power is maximum scheduled with the optimal deployment and operation of DPFC, which confirms the applicability and effectiveness of the proposed method.

Planning construction of integrative schedule management for nuclear power project

International Nuclear Information System (INIS)

Zeng Zhenglin; Wang Wenying; Peng Fei

2012-01-01

This paper introduces the planning construction of integrative schedule management for Nuclear Power Project. It details schedule management system and the requirement of schedulers and the mode of three schedule management flats. And analysis it combing with the implementation of construction water and all special schedules before FCD to further propose the improving and researching direction for the integrative schedule management. (authors)

Voltage scheduling for low power/energy

Science.gov (United States)

Manzak, Ali

2001-07-01

Power considerations have become an increasingly dominant factor in the design of both portable and desk-top systems. An effective way to reduce power consumption is to lower the supply voltage since voltage is quadratically related to power. This dissertation considers the problem of lowering the supply voltage at (i) the system level and at (ii) the behavioral level. At the system level, the voltage of the variable voltage processor is dynamically changed with the work load. Processors with limited sized buffers as well as those with very large buffers are considered. Given the task arrival times, deadline times, execution times, periods and switching activities, task scheduling algorithms that minimize energy or peak power are developed for the processors equipped with very large buffers. A relation between the operating voltages of the tasks for minimum energy/power is determined using the Lagrange multiplier method, and an iterative algorithm that utilizes this relation is developed. Experimental results show that the voltage assignment obtained by the proposed algorithm is very close (0.1% error) to that of the optimal energy assignment and the optimal peak power (1% error) assignment. Next, on-line and off-fine minimum energy task scheduling algorithms are developed for processors with limited sized buffers. These algorithms have polynomial time complexity and present optimal (off-line) and close-to-optimal (on-line) solutions. A procedure to calculate the minimum buffer size given information about the size of the task (maximum, minimum), execution time (best case, worst case) and deadlines is also presented. At the behavioral level, resources operating at multiple voltages are used to minimize power while maintaining the throughput. Such a scheme has the advantage of allowing modules on the critical paths to be assigned to the highest voltage levels (thus meeting the required timing constraints) while allowing modules on non-critical paths to be assigned

Electric power systems advanced forecasting techniques and optimal generation scheduling

CERN Document Server

Catalão, João P S

2012-01-01

Overview of Electric Power Generation SystemsCláudio MonteiroUncertainty and Risk in Generation SchedulingRabih A. JabrShort-Term Load ForecastingAlexandre P. Alves da Silva and Vitor H. FerreiraShort-Term Electricity Price ForecastingNima AmjadyShort-Term Wind Power ForecastingGregor Giebel and Michael DenhardPrice-Based Scheduling for GencosGovinda B. Shrestha and Songbo QiaoOptimal Self-Schedule of a Hydro Producer under UncertaintyF. Javier Díaz and Javie

Evaluating the effectiveness of mixed-integer linear programming for day-ahead hydro-thermal self-scheduling considering price uncertainty and forced outage rate

International Nuclear Information System (INIS)

Esmaeily, Ali; Ahmadi, Abdollah; Raeisi, Fatima; Ahmadi, Mohammad Reza; Esmaeel Nezhad, Ali; Janghorbani, Mohammadreza

2017-01-01

A new optimization framework based on MILP model is introduced in the paper for the problem of stochastic self-scheduling of hydrothermal units known as HTSS Problem implemented in a joint energy and reserve electricity market with day-ahead mechanism. The proposed MILP framework includes some practical constraints such as the cost due to valve-loading effect, the limit due to DRR and also multi-POZs, which have been less investigated in electricity market models. For the sake of more accuracy, for hydro generating units’ model, multi performance curves are also used. The problem proposed in this paper is formulated using a model on the basis of a stochastic optimization technique while the objective function is maximizing the expected profit utilizing MILP technique. The suggested stochastic self-scheduling model employs the price forecast error in order to take into account the uncertainty due to price. Besides, LMCS is combined with roulette wheel mechanism so that the scenarios corresponding to the non-spinning reserve price and spinning reserve price as well as the energy price at each hour of the scheduling are generated. Finally, the IEEE 118-bus power system is used to indicate the performance and the efficiency of the suggested technique. - Highlights: • Characterizing the uncertainties of price and FOR of units. • Replacing the fixed ramping rate constraints with the dynamic ones. • Proposing linearized model for the valve-point effects of thermal units. • Taking into consideration the multi-POZs relating to the thermal units. • Taking into consideration the multi-performance curves of hydroelectric units.

Coordinated Scheduling and Power Control in Cloud-Radio Access Networks

KAUST Repository

Douik, Ahmed

2015-12-01

This paper addresses the joint coordinated scheduling and power control problem in cloud-enabled networks. Consider the downlink of a cloud-radio access network (CRAN), where the cloud is only responsible for the scheduling policy, power control, and synchronization of the transmit frames across the single-antenna base-stations (BS). The transmit frame consists of several time/frequency blocks, called power-zones (PZ). The paper considers the problem of scheduling users to PZs and determining their power levels (PL), by maximizing the weighted sum-rate under the practical constraints that each user cannot be served by more than one base-station, but can be served by one or more power-zones within each base-station frame. The paper solves the problem using a graph theoretical approach by introducing the joint scheduling and power control graph formed by several clusters, where each is formed by a set of vertices, representing the possible association of users, BSs, and PLs for one specific PZ. The problem is, then, formulated as a maximumweight clique problem, in which the weight of each vertex is the sum of the benefits of the individual associations belonging to that vertex. Simulation results suggest that the proposed crosslayer scheme provides appreciable performance improvement as compared to schemes from recent literature.

Coordinated Scheduling and Power Control in Cloud-Radio Access Networks

KAUST Repository

Douik, Ahmed; Dahrouj, Hayssam; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2015-01-01

This paper addresses the joint coordinated scheduling and power control problem in cloud-enabled networks. Consider the downlink of a cloud-radio access network (CRAN), where the cloud is only responsible for the scheduling policy, power control, and synchronization of the transmit frames across the single-antenna base-stations (BS). The transmit frame consists of several time/frequency blocks, called power-zones (PZ). The paper considers the problem of scheduling users to PZs and determining their power levels (PL), by maximizing the weighted sum-rate under the practical constraints that each user cannot be served by more than one base-station, but can be served by one or more power-zones within each base-station frame. The paper solves the problem using a graph theoretical approach by introducing the joint scheduling and power control graph formed by several clusters, where each is formed by a set of vertices, representing the possible association of users, BSs, and PLs for one specific PZ. The problem is, then, formulated as a maximumweight clique problem, in which the weight of each vertex is the sum of the benefits of the individual associations belonging to that vertex. Simulation results suggest that the proposed crosslayer scheme provides appreciable performance improvement as compared to schemes from recent literature.

Distributed continuous energy scheduling for dynamic virtual power plants

International Nuclear Information System (INIS)

Niesse, Astrid

2015-01-01

This thesis presents DynaSCOPE as distributed control method for continuous energy scheduling for dynamic virtual power plants (DVPP). DVPPs aggregate the flexibility of distributed energy units to address current energy markets. As an extension of the Virtual Power Plant concept they show high dynamics in aggregation and operation of energy units. Whereas operation schedules are set up for all energy units in a day-ahead planning procedure, incidents may render these schedules infeasible during execution, like deviation from prognoses or outages. Thus, a continuous scheduling process is needed to ensure product fulfillment. With DynaSCOPE, software agents representing single energy units solve this problem in a completely distributed heuristic approach. Using a stepped concept, several damping mechanisms are applied to allow minimum disturbance while continuously trying to fulfill the product as contracted at the market.

Engineering schedule control of nuclear power project planning and management

International Nuclear Information System (INIS)

Meng Hao

2014-01-01

Nuclear power design is the important part of project management of nuclear power project, it is the way to control the project organization, design schedule, design progress, design quality and cost control. The good schedule system and control is the key to the success for the project. It is also analyzed the problem during the project, by using some theory and analyze the project structure, design schedule management, IED and document management and interface management propose some new idea for better improve the design management to finally better improve the management quality and efficiency. (author)

Sensor Transmission Power Schedule for Smart Grids

Science.gov (United States)

Gao, C.; Huang, Y. H.; Li, J.; Liu, X. D.

2017-11-01

Smart grid has attracted much attention by the requirement of new generation renewable energy. Nowadays, the real-time state estimation, with the help of phasor measurement unit, plays an important role to keep smart grid stable and efficient. However, the limitation of the communication channel is not considered by related work. Considering the familiar limited on-board batteries wireless sensor in smart grid, transmission power schedule is designed in this paper, which minimizes energy consumption with proper EKF filtering performance requirement constrain. Based on the event-triggered estimation theory, the filtering algorithm is also provided to utilize the information contained in the power schedule. Finally, its feasibility and performance is demonstrated using the standard IEEE 39-bus system with phasor measurement units (PMUs).

Management information system for cost-schedule integration control for nuclear power projects

International Nuclear Information System (INIS)

Liu Wei; Wang Yongqing; Tian Li

2001-01-01

Based on the project management experience abroad and at home, a cost-schedule integration control model was developed to improve nuclear power project management. The model integrates cost data with the scheduling data by unity coding to efficiently implement cost-schedule integration control on line. The software system architecture and database is designed and implemented. The system functions include estimating and forecasting dynamically cash flow, scheduling and evaluating deviation from the cost-schedule plan, etc. The research and development of the system should improve the architecture of computer integrated management information systems for nuclear power projects in China

Power-scheduling - Introduction of the FPBG1 System

International Nuclear Information System (INIS)

Braun, A.; Meier, W.

2006-01-01

This article takes a look at the Scheduled Balance Group system (in German: 'Fahrplanbilanzgruppensystem', FPBG) which was successfully introduced in Switzerland in December 2005. The development of the system is described and the reasons for the development of a new concept for Switzerland are discussed. The system permits the use of standard European scheduling processes for national and international power traders and supports Switzerland's function as an important power hub in Europe. The basics behind the concept are discussed and the mechanisms of its functioning are illustrated in graphical form. The implementation of the system by the ETRANS company is looked at and various questions posed in this connection are answered

A thermoelectric cap for seafloor hydrothermal vents

International Nuclear Information System (INIS)

Xie, Yu; Wu, Shi-jun; Yang, Can-jun

2016-01-01

Highlights: • We developed a thermoelectric cap (TC) to harvest hydrothermal energy. • The TC was deployed at a hydrothermal vent site near Kueishantao islet, Taiwan. • The TC monitored the temperature of the hydrothermal fluids during the field test. • The TC could make the thermal energy of hydrothermal fluids a viable power source. - Abstract: Long-term in situ monitoring is crucial to seafloor scientific investigations. One of the challenges of operating sensors in seabed is the lifespan of the sensors. Such sensors are commonly powered by batteries when other alternatives, such as tidal or solar energy, are unavailable. However, the batteries have a limited lifespan and must be recharged or replaced periodically, which is costly and impractical. A thermoelectric cap, which harvests the thermal energy of hydrothermal fluids through a conduction pipe and converts the heat to electrical energy by using thermoelectric generators, was developed to avoid these inconveniences. The thermoelectric cap was combined with a power and temperature measurement system that enables the thermoelectric cap to power a light-emitting diode lamp, an electronic load (60 Ω), and 16 thermocouples continuously. The thermoelectric cap was field tested at a shallow hydrothermal vent site near Kueishantao islet, which is located offshore of northeastern Taiwan. By using the thermal gradient between hydrothermal fluids and seawater, the thermoelectric cap obtained a sustained power of 0.2–0.5 W during the field test. The thermoelectric cap successfully powered the 16 thermocouples and recorded the temperature of the hydrothermal fluids during the entire field test. Our results show that the thermal energy of hydrothermal fluids can be an alternative renewable power source for oceanographic research.

Application of linear scheduling method (LSM) for nuclear power plant (NPP) construction

International Nuclear Information System (INIS)

Kim, Woojoong; Ryu, Dongsoo; Jung, Youngsoo

2014-01-01

Highlights: • Mixed use of linear scheduling method with traditional CPM is suggested for NPP. • A methodology for selecting promising areas for LSM application is proposed. • A case-study is conducted to validate the proposed LSM selection methodology. • A case-study of reducing NPP construction duration by using LSM is introduced. - Abstract: According to a forecast, global energy demand is expected to increase by 56% from 2010 to 2040 (EIA, 2013). The nuclear power plant construction market is also growing with sharper competition. In nuclear power plant construction, scheduling is one of the most important functions due to its large size and complexity. Therefore, it is crucial to incorporate the ‘distinct characteristics of construction commodities and the complex characteristics of scheduling techniques’ (Jung and Woo, 2004) when selecting appropriate schedule control methods for nuclear power plant construction. However, among various types of construction scheduling techniques, the traditional critical path method (CPM) has been used most frequently in real-world practice. In this context, the purpose of this paper is to examine the viability and effectiveness of linear scheduling method (LSM) applications for specific areas in nuclear power plant construction. In order to identify the criteria for selecting scheduling techniques, the characteristics of CPM and LSM were compared and analyzed first through a literature review. Distinct characteristics of nuclear power plant construction were then explored by using a case project in order to develop a methodology to select effective areas of LSM application to nuclear power plant construction. Finally, promising areas for actual LSM application are suggested based on the proposed evaluation criteria and the case project. Findings and practical implications are discussed for further implementation

Application of linear scheduling method (LSM) for nuclear power plant (NPP) construction

Energy Technology Data Exchange (ETDEWEB)

Kim, Woojoong, E-mail: minidung@nate.com [Central Research Institute, Korea Hydro and Nuclear Power Co., Ltd, Daejeon 305-343 (Korea, Republic of); Ryu, Dongsoo, E-mail: energyboy@khnp.co.kr [Central Research Institute, Korea Hydro and Nuclear Power Co., Ltd, Daejeon 305-343 (Korea, Republic of); Jung, Youngsoo, E-mail: yjung97@mju.ac.kr [College of Architecture, Myongji University, Yongin 449-728 (Korea, Republic of)

2014-04-01

Highlights: • Mixed use of linear scheduling method with traditional CPM is suggested for NPP. • A methodology for selecting promising areas for LSM application is proposed. • A case-study is conducted to validate the proposed LSM selection methodology. • A case-study of reducing NPP construction duration by using LSM is introduced. - Abstract: According to a forecast, global energy demand is expected to increase by 56% from 2010 to 2040 (EIA, 2013). The nuclear power plant construction market is also growing with sharper competition. In nuclear power plant construction, scheduling is one of the most important functions due to its large size and complexity. Therefore, it is crucial to incorporate the ‘distinct characteristics of construction commodities and the complex characteristics of scheduling techniques’ (Jung and Woo, 2004) when selecting appropriate schedule control methods for nuclear power plant construction. However, among various types of construction scheduling techniques, the traditional critical path method (CPM) has been used most frequently in real-world practice. In this context, the purpose of this paper is to examine the viability and effectiveness of linear scheduling method (LSM) applications for specific areas in nuclear power plant construction. In order to identify the criteria for selecting scheduling techniques, the characteristics of CPM and LSM were compared and analyzed first through a literature review. Distinct characteristics of nuclear power plant construction were then explored by using a case project in order to develop a methodology to select effective areas of LSM application to nuclear power plant construction. Finally, promising areas for actual LSM application are suggested based on the proposed evaluation criteria and the case project. Findings and practical implications are discussed for further implementation.

Rolling scheduling of electric power system with wind power based on improved NNIA algorithm

Science.gov (United States)

Xu, Q. S.; Luo, C. J.; Yang, D. J.; Fan, Y. H.; Sang, Z. X.; Lei, H.

2017-11-01

This paper puts forth a rolling modification strategy for day-ahead scheduling of electric power system with wind power, which takes the operation cost increment of unit and curtailed wind power of power grid as double modification functions. Additionally, an improved Nondominated Neighbor Immune Algorithm (NNIA) is proposed for solution. The proposed rolling scheduling model has further improved the operation cost of system in the intra-day generation process, enhanced the system’s accommodation capacity of wind power, and modified the key transmission section power flow in a rolling manner to satisfy the security constraint of power grid. The improved NNIA algorithm has defined an antibody preference relation model based on equal incremental rate, regulation deviation constraints and maximum & minimum technical outputs of units. The model can noticeably guide the direction of antibody evolution, and significantly speed up the process of algorithm convergence to final solution, and enhance the local search capability.

Abstract flexibility description for virtual power plant scheduling

OpenAIRE

Fröhling, Judith

2017-01-01

In the ongoing paradigm shift of the energy market from big power plants to more and more small and decentralized power plants, virtual power plants (VPPs) play an important role. VPPs bundle the capacities of the small and decentralized resources (DER). Planing of VPP operation, that is also called scheduling, relies on the flexibilities of controllable DER in the VPP, e.g., combined heat and power plants (CHPs), heat pumps and batteries. The aim of this thesis is the development of an abstr...

Automatic scheduling of maintenance work in nuclear power plants

International Nuclear Information System (INIS)

Kasahara, T.; Nishizawa, Y.; Kato, K.; Kiguchi, T.

1987-01-01

An automatic scheduling method for maintenance work in nuclear power plants has been developed using an AI technique. The purpose of this method is to help plant operators by adjusting the time schedule of various kinds of maintenance work so that incorrect ordering or timing of plant manipulations does not cause undersirable results, such as a plant trip. The functions of the method were tested by off-line simulations. The results show that the method can produce a satisfactory schedule of plant component manipulations without interference between the tasks and plant conditions

Scheduling the powering tests

CERN Document Server

Barbero-Soto, E; Casas-Lino, M P; Fernandez-Robles, C; Foraz, K; Pojer, M; Saban, R; Schmidt, R; Solfaroli-Camillocci, M; Vergara-Fernandez, A

2008-01-01

The Large Hadron Collider is now entering in its final phase before receiving beam, and the activities at CERN between 2007 and 2008 have shifted from installation work to the commissioning of the technical systems ("hardware commissioning"). Due to the unprecedented complexity of this machine, all the systems are or will be tested as far as possible before the cool-down starts. Systems are firstly tested individually before being globally tested together. The architecture of LHC, which is partitioned into eight cryogenically and electrically independent sectors, allows the commissioning on a sector by sector basis. When a sector reaches nominal cryogenic conditions, commissioning of the magnet powering system to nominal current for all magnets can be performed. This paper briefly describes the different activities to be performed during the powering tests of the superconducting magnet system and presents the scheduling issues raised by co-activities as well as the management of resources.

Scheduled Operation of PV Power Station Considering Solar Radiation Forecast Error

Science.gov (United States)

Takayama, Satoshi; Hara, Ryoichi; Kita, Hiroyuki; Ito, Takamitsu; Ueda, Yoshinobu; Saito, Yutaka; Takitani, Katsuyuki; Yamaguchi, Koji

Massive penetration of photovoltaic generation (PV) power stations may cause some serious impacts on a power system operation due to their volatile and unpredictable output. Growth of uncertainty may require larger operating reserve capacity and regulating capacity. Therefore, in order to utilize a PV power station as an alternative for an existing power plant, improvement in controllability and adjustability of station output become very important factor. Purpose of this paper is to develop the scheduled operation technique using a battery system (NAS battery) and the meteorological forecast. The performance of scheduled operation strongly depends on the accuracy of solar radiation forecast. However, the solar radiation forecast contains error. This paper proposes scheduling method and rescheduling method considering the trend of forecast error. More specifically, the forecast error scenario is modeled by means of the clustering analysis of the past actual forecast error. Validity and effectiveness of the proposed method is ascertained through computational simulations using the actual PV generation data monitored at the Wakkanai PV power station and solar radiation forecast data provided by the Japan Weather Association.

Multi-objective differential evolution with adaptive Cauchy mutation for short-term multi-objective optimal hydro-thermal scheduling

Energy Technology Data Exchange (ETDEWEB)

Qin Hui [College of Hydropower and Information Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhou Jianzhong, E-mail: jz.zhou@hust.edu.c [College of Hydropower and Information Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Lu Youlin; Wang Ying; Zhang Yongchuan [College of Hydropower and Information Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2010-04-15

A new multi-objective optimization method based on differential evolution with adaptive Cauchy mutation (MODE-ACM) is presented to solve short-term multi-objective optimal hydro-thermal scheduling (MOOHS) problem. Besides fuel cost, the pollutant gas emission is also optimized as an objective. The water transport delay between connected reservoirs and the effect of valve-point loading of thermal units are also taken into account in the presented problem formulation. The proposed algorithm adopts an elitist archive to retain non-dominated solutions obtained during the evolutionary process. It modifies the DE's operators to make it suit for multi-objective optimization (MOO) problems and improve its performance. Furthermore, to avoid premature convergence, an adaptive Cauchy mutation is proposed to preserve the diversity of population. An effective constraints handling method is utilized to handle the complex equality and inequality constraints. The effectiveness of the proposed algorithm is tested on a hydro-thermal system consisting of four cascaded hydro plants and three thermal units. The results obtained by MODE-ACM are compared with several previous studies. It is found that the results obtained by MODE-ACM are superior in terms of fuel cost as well as emission output, consuming a shorter time. Thus it can be a viable alternative to generate optimal trade-offs for short-term MOOHS problem.

Day-ahead resource scheduling of a renewable energy based virtual power plant

International Nuclear Information System (INIS)

Zamani, Ali Ghahgharaee; Zakariazadeh, Alireza; Jadid, Shahram

2016-01-01

Highlights: • Simultaneous energy and reserve scheduling of a VPP. • Aggregate uncertainties of electricity prices, renewable generation and load demand. • Develop a stochastic scheduling model using the point estimate method. - Abstract: The evolution of energy markets is accelerating in the direction of a greater reliance upon distributed energy resources (DERs). To manage this increasing two-way complexity, virtual power plants (VPPs) are being deployed today all over the world. In this paper, a probabilistic model for optimal day ahead scheduling of electrical and thermal energy resources in a VPP is proposed where participation of energy storage systems and demand response programs (DRPs) are also taken into account. In the proposed model, energy and reserve is simultaneously scheduled considering the uncertainties of market prices, electrical demand and intermittent renewable power generation. The Point Estimate Method (PEM) is applied in order to model the uncertainties of VPP’s scheduling problem. Moreover, the optimal reserve scheduling of VPP is presented which efficiently decreases VPP’s risk facing the unexpected fluctuations of uncertain parameters at the power delivery time. The results demonstrated that implementation of demand response programs (DRPs) would decrease total operation costs of VPP as well as its dependency on the upstream network.

Power scheduling in islanded-mode microgrids using fuel cell vehicles

NARCIS (Netherlands)

Alavi, Farid; Van De Wouw, Nathan; De Schutter, Bart

2018-01-01

We consider power scheduling in a microgrid operated in the islanded mode. It is assumed that at any time all the renewable energy sources are generating the maximum achievable electrical power based on the weather conditions and the power balance of the microgrid is exclusively done by a fleet of

Research on Power System Scheduling Improving Wind Power Accommodation Considering Thermal Energy Storage and Flexible Load

Science.gov (United States)

Zou, Chenlu; Cui, Xue; Wang, Heng; Zhou, Bin; Liu, Yang

2018-01-01

In the case of rapid development of wind power and heavy wind curtailment, the study of wind power accommodation of combined heat and power system has become the focus of attention. A two-stage scheduling model contains of wind power, thermal energy storage, CHP unit and flexible load were constructed. This model with the objective function of minimizing wind curtailment and the operation cost of units while taking into account of the total coal consumption of units, constraint of thermal energy storage and electricity-heat characteristic of CHP. This paper uses MICA to solve the problem of too many constraints and make the solution more feasible. A numerical example showed that the two stage decision scheduling model can consume more wind power, and it could provide a reference for combined heat and power system short-term operation

An On-Time Power-Aware Scheduling Scheme for Medical Sensor SoC-Based WBAN Systems

Science.gov (United States)

Hwang, Tae-Ho; Kim, Dong-Sun; Kim, Jung-Guk

2013-01-01

The focus of many leading technologies in the field of medical sensor systems is on low power consumption and robust data transmission. For example, the implantable cardioverter-defibrillator (ICD), which is used to maintain the heart in a healthy state, requires a reliable wireless communication scheme with an extremely low duty-cycle, high bit rate, and energy-efficient media access protocols. Because such devices must be sustained for over 5 years without access to battery replacement, they must be designed to have extremely low power consumption in sleep mode. Here, an on-time, energy-efficient scheduling scheme is proposed that performs power adjustments to minimize the sleep-mode current. The novelty of this scheduler is that it increases the determinacy of power adjustment and the predictability of scheduling by employing non-pre-emptible dual priority scheduling. This predictable scheduling also guarantees the punctuality of important periodic tasks based on their serialization, by using their worst case execution time) and the power consumption optimization. The scheduler was embedded into a system on chip (SoC) developed to support the wireless body area network—a wakeup-radio and wakeup-timer for implantable medical devices. This scheduling system is validated by the experimental results of its performance when used with life-time extensions of ICD devices. PMID:23271602

An on-time power-aware scheduling scheme for medical sensor SoC-based WBAN systems.

Science.gov (United States)

Hwang, Tae-Ho; Kim, Dong-Sun; Kim, Jung-Guk

2012-12-27

The focus of many leading technologies in the field of medical sensor systems is on low power consumption and robust data transmission. For example, the implantable cardioverter-defibrillator (ICD), which is used to maintain the heart in a healthy state, requires a reliable wireless communication scheme with an extremely low duty-cycle, high bit rate, and energy-efficient media access protocols. Because such devices must be sustained for over 5 years without access to battery replacement, they must be designed to have extremely low power consumption in sleep mode. Here, an on-time, energy-efficient scheduling scheme is proposed that performs power adjustments to minimize the sleep-mode current. The novelty of this scheduler is that it increases the determinacy of power adjustment and the predictability of scheduling by employing non-pre-emptible dual priority scheduling. This predictable scheduling also guarantees the punctuality of important periodic tasks based on their serialization, by using their worst case execution time) and the power consumption optimization. The scheduler was embedded into a system on chip (SoC) developed to support the wireless body area network-a wakeup-radio and wakeup-timer for implantable medical devices. This scheduling system is validated by the experimental results of its performance when used with life-time extensions of ICD devices.

Tri-generation based hybrid power plant scheduling for renewable resources rich area with energy storage

International Nuclear Information System (INIS)

Pazheri, F.R.

2015-01-01

Highlights: • Involves scheduling of the tri-generation based hybrid power plant. • Utilization of renewable energy through energy storage is discussed. • Benefits of the proposed model are illustrated. • Energy efficient and environmental friendly dispatch is analyzed. • Modeled scheduling problem is applicable to any fuel enriched area. - Abstract: Solving power system scheduling is crucial to ensure smooth operations of the electric power industry. Effective utilization of available conventional and renewable energy sources (RES) by tri-generation and with the aid of energy storage facilities (ESF) can ensure clean and energy efficient power generation. Such power generation can play an important role in countries, like Saudi Arabia, where abundant fossil fuels (FF) and renewable energy sources (RES) are available. Hence, effective modeling of such hybrid power systems scheduling is essential in such countries based on the available fuel resources. The intent of this paper is to present a simple model for tri-generation based hybrid power system scheduling for energy resources rich area in presence of ESF, to ensure optimum fuel utilization and minimum pollutant emissions while meeting the power demand. This research points an effective operation strategy which ensure a clean and energy efficient power scheduling by exploiting available energy resources effectively. Hence, it has an important role in current and future power generation. In order to illustrate the benefits of the presented approach a clean and energy efficient hybrid power supply scheme for King Saud University (KSU), Saudi Arabia, is proposed and analyzed here. Results show that the proposed approach is very suitable for KSU since adequate solar power is available during its peak demand periods

Multi-objective optimization of short-term hydrothermal scheduling using non-dominated sorting gravitational search algorithm with chaotic mutation

International Nuclear Information System (INIS)

Tian, Hao; Yuan, Xiaohui; Ji, Bin; Chen, Zhihuan

2014-01-01

Highlights: • An improved non-dominated sorting gravitational search algorithm (NSGSA-CM) is proposed. • NSGSA-CM is used to solve the problem of short-term multi-objective hydrothermal scheduling. • We enhance the search capability of NSGSA-CM by chaotic mutation. • New strategies are devised to handle various constraints in NSGSA-CM. • We obtain better compromise solutions with less fuel cost and emissions. - Abstract: This paper proposes a non-dominated sorting gravitational search algorithm with chaotic mutation (NSGSA-CM) to solve short-term economic/environmental hydrothermal scheduling (SEEHTS) problem. The SEEHTS problem is formulated as a multi-objective optimization problem with many equality and inequality constraints. By introducing the concept of non-dominated sorting and crowding distance, NSGSA-CM can optimize two objectives of fuel cost and pollutant emission simultaneously and obtain a set of Pareto optimal solutions in one trial. In order to improve the performance of NSGSA-CM, the paper introduces particle memory character and population social information in velocity update process. And a chaotic mutation is adopted to prevent the premature convergence. Furthermore, NSGSA-CM utilizes an elitism strategy which selects better solutions in parent and offspring populations based on their non-domination rank and crowding distance to update new generations. When dealing with the constraints of the SEEHTS, new strategies without penalty factors are proposed. In order to handle the water dynamic balance and system load balance constraints, this paper uses a combined strategy which adjusts the violation averagely to each decision variable at first and adjusts the rest violation randomly later. Meanwhile, a new symmetrical adjustment strategy by modifying the discharges at current and later interval without breaking water dynamic balance is adopted to handle reservoir storage constraints. To test the performance of the proposed NSGSA

An On-Time Power-Aware Scheduling Scheme for Medical Sensor SoC-Based WBAN Systems

Directory of Open Access Journals (Sweden)

Jung-Guk Kim

2012-12-01

Full Text Available The focus of many leading technologies in the field of medical sensor systems is on low power consumption and robust data transmission. For example, the implantable cardioverter-defibrillator (ICD, which is used to maintain the heart in a healthy state, requires a reliable wireless communication scheme with an extremely low duty-cycle, high bit rate, and energy-efficient media access protocols. Because such devices must be sustained for over 5 years without access to battery replacement, they must be designed to have extremely low power consumption in sleep mode. Here, an on-time, energy-efficient scheduling scheme is proposed that performs power adjustments to minimize the sleep-mode current. The novelty of this scheduler is that it increases the determinacy of power adjustment and the predictability of scheduling by employing non-pre-emptible dual priority scheduling. This predictable scheduling also guarantees the punctuality of important periodic tasks based on their serialization, by using their worst case execution time and the power consumption optimization. The scheduler was embedded into a system on chip (SoC developed to support the wireless body area network—a wakeup-radio and wakeup-timer for implantable medical devices. This scheduling system is validated by the experimental results of its performance when used with life-time extensions of ICD devices.

Scheduling the maintenance of gaseous diffusion and electric power distribution plants

International Nuclear Information System (INIS)

Chauvet, D.

1990-01-01

A computer aided scheduling applied to the maintenance of a uranium enrichment plant is presented. The plant exploits gaseous diffusion and electric power distribution plants, for which the operating conditions must be satisfied. The management and the execution of the maintenance actions are computer aided. Concerning the techniques, the cost, the safety and the scheduling actions were optimized [fr

Brokdorf nuclear power station: Construction scheduling and deadline control

International Nuclear Information System (INIS)

Lembcke, U.D.F.

1986-01-01

Scheduling, especially deadline control, for all installations of the Brokdorf nuclear power station was carried out centrally by the Project Management of Kraftwerk Union AG. 130 timetables encompassing some 13,000 activities were handled, which were interconnected and linked to 189 timetables (approx. 18,000 activities) from various specialized sections by means of data processing systems. Much space in time scheduling was taken by controls of software processing, especially of the preliminary inspection documents in the piping sector and of working documents for construction management in the control systems area. (orig.) [de

Nuclear power plant maintenance scheduling dilemma: a genetic algorithm approach

International Nuclear Information System (INIS)

Mahdavi, M.H.; Modarres, M.

2004-01-01

There are huge numbers of components scheduled for maintenance when a nuclear power plant is shut down. Among these components, a number of them are safety related which their operability as well as reliability when plant becomes up is main concerns. Not performing proper maintenance on this class of components/system would impose substantial risk on operating the NPP. In this paper a new approach based on genetic algorithms is presented to optimize the NPP maintenance schedule during shutdown. following this approach the cost incurred by maintenance activities for each schedule is balanced with the risk imposed by the maintenance scheduling plan to the plant operation status when it is up. The risk model implemented in the GA scheduler as its evaluation function is developed on the basis of the probabilistic risk assessment methodology. the Ga optimizers itself is shown to be superior compared to other optimization methods such as the monte carlo technique

Gain-Scheduled Control of a Fossil-Fired Power Plant Boiler

DEFF Research Database (Denmark)

Hangstrup, M.; Stoustrup, Jakob; Andersen, Palle

1999-01-01

-scheduling which interpolates between unstable controllers is not allowed using traditional schemes. The results show that a considerable optimization of the conventional controlled system is obtainable. Also the gain-scheduled optimizing controller is seen to have a superior performance compared to the fixed LTI......In this paper the objective is to optimize the control of a coal fired 250 MW power plant boiler. The conventional control system is supplemented with a multivariable optimizing controller operating in parallel with the conventional control system. Due to the strong dependence of the gains...... and dynamics upon the load, it is beneficial to consider a gain-scheduling control approach. Optimization using complex mu synthesis results in unstable LTI controllers in some operating points of the boiler. A recent gain-scheduling approach allowing for unstable fixed LTI controllers is applied. Gain...

Power generation scheduling. A free market based procedure with reserve constraints included

International Nuclear Information System (INIS)

Huse, Einar Staale

1998-01-01

This thesis deals with the short-term scheduling of electric power generation in a competitive market. This involves determination of start-ups and shut-downs, and production levels of all units in all hours of the optimization period, considering unit characteristics and system restrictions. The unit characteristics and restrictions handled are minimum and maximum production levels, fuel cost function, start-up costs, minimum up time and minimum down time. The system restrictions handled are power balance (supply equals demand in all hours) and spinning reserve requirement. The thesis has two main contributions: (1) A new organization of an hourly electric power market that simultaneously sets the price of both energy and reserve power is proposed. A power exchange is used as a trading place for electricity. Its responsibility is to balance supply and demand bids and to secure enough spinning reserve. Routines for bidding and market clearing are developed. (2) A computer programme that simulates the proposed electricity market has been implemented. The program can also be used as a new method for solving the single owner generation scheduling problem. Simulations show that the performance of the program is excellent. Simulations also show that it is possible to obtain efficient schedules through the proposed electricity market. 37 refs., 20 figs., 15 tabs

Power generation scheduling. A free market based procedure with reserve constraints included

Energy Technology Data Exchange (ETDEWEB)

Huse, Einar Staale

1999-12-31

This thesis deals with the short-term scheduling of electric power generation in a competitive market. This involves determination of start-ups and shut-downs, and production levels of all units in all hours of the optimization period, considering unit characteristics and system restrictions. The unit characteristics and restrictions handled are minimum and maximum production levels, fuel cost function, start-up costs, minimum up time and minimum down time. The system restrictions handled are power balance (supply equals demand in all hours) and spinning reserve requirement. The thesis has two main contributions: (1) A new organization of an hourly electric power market that simultaneously sets the price of both energy and reserve power is proposed. A power exchange is used as a trading place for electricity. Its responsibility is to balance supply and demand bids and to secure enough spinning reserve. Routines for bidding and market clearing are developed. (2) A computer programme that simulates the proposed electricity market has been implemented. The program can also be used as a new method for solving the single owner generation scheduling problem. Simulations show that the performance of the program is excellent. Simulations also show that it is possible to obtain efficient schedules through the proposed electricity market. 37 refs., 20 figs., 15 tabs.

Power generation scheduling. A free market based procedure with reserve constraints included

Energy Technology Data Exchange (ETDEWEB)

Huse, Einar Staale

1998-12-31

This thesis deals with the short-term scheduling of electric power generation in a competitive market. This involves determination of start-ups and shut-downs, and production levels of all units in all hours of the optimization period, considering unit characteristics and system restrictions. The unit characteristics and restrictions handled are minimum and maximum production levels, fuel cost function, start-up costs, minimum up time and minimum down time. The system restrictions handled are power balance (supply equals demand in all hours) and spinning reserve requirement. The thesis has two main contributions: (1) A new organization of an hourly electric power market that simultaneously sets the price of both energy and reserve power is proposed. A power exchange is used as a trading place for electricity. Its responsibility is to balance supply and demand bids and to secure enough spinning reserve. Routines for bidding and market clearing are developed. (2) A computer programme that simulates the proposed electricity market has been implemented. The program can also be used as a new method for solving the single owner generation scheduling problem. Simulations show that the performance of the program is excellent. Simulations also show that it is possible to obtain efficient schedules through the proposed electricity market. 37 refs., 20 figs., 15 tabs.

A fast method for the unit scheduling problem with significant renewable power generation

International Nuclear Information System (INIS)

Osório, G.J.; Lujano-Rojas, J.M.; Matias, J.C.O.; Catalão, J.P.S.

2015-01-01

Highlights: • A model to the scheduling of power systems with significant renewable power generation is provided. • A new methodology that takes information from the analysis of each scenario separately is proposed. • Based on a probabilistic analysis, unit scheduling and corresponding economic dispatch are estimated. • A comparison with others methodologies is in favour of the proposed approach. - Abstract: Optimal operation of power systems with high integration of renewable power sources has become difficult as a consequence of the random nature of some sources like wind energy and photovoltaic energy. Nowadays, this problem is solved using Monte Carlo Simulation (MCS) approach, which allows considering important statistical characteristics of wind and solar power production such as the correlation between consecutive observations, the diurnal profile of the forecasted power production, and the forecasting error. However, MCS method requires the analysis of a representative amount of trials, which is an intensive calculation task that increases considerably with the number of scenarios considered. In this paper, a model to the scheduling of power systems with significant renewable power generation based on scenario generation/reduction method, which establishes a proportional relationship between the number of scenarios and the computational time required to analyse them, is proposed. The methodology takes information from the analysis of each scenario separately to determine the probabilistic behaviour of each generator at each hour in the scheduling problem. Then, considering a determined significance level, the units to be committed are selected and the load dispatch is determined. The proposed technique was illustrated through a case study and the comparison with stochastic programming approach was carried out, concluding that the proposed methodology can provide an acceptable solution in a reduced computational time

An Adaptive Power Efficient Packet Scheduling Algorithm for Wimax Networks

OpenAIRE

R Murali Prasad; P. Satish Kumar

2010-01-01

Admission control schemes and scheduling algorithms are designed to offer QoS services in 802.16/802.16e networks and a number of studies have investigated these issues. But the channel condition and priority of traffic classes are very rarely considered in the existing scheduling algorithms. Although a number of energy saving mechanisms have been proposed for the IEEE 802.16e, to minimize the power consumption of IEEE 802.16e mobile stations with multiple real-time connections has not yet be...

A Multiobjective Robust Scheduling Optimization Mode for Multienergy Hybrid System Integrated by Wind Power, Solar Photovoltaic Power, and Pumped Storage Power

Directory of Open Access Journals (Sweden)

Lihui Zhang

2017-01-01

Full Text Available Wind power plant (WPP, photovoltaic generators (PV, cell-gas turbine (CGT, and pumped storage power station (PHSP are integrated into multienergy hybrid system (MEHS. Firstly, this paper presents MEHS structure and constructs a scheduling model with the objective functions of maximum economic benefit and minimum power output fluctuation. Secondly, in order to relieve the uncertainty influence of WPP and PV on system, robust stochastic theory is introduced to describe uncertainty and propose a multiobjective stochastic scheduling optimization mode by transforming constraint conditions with uncertain variables. Finally, a 9.6 MW WPP, a 6.5 MW PV, three CGT units, and an upper reservoir with 10 MW·h equivalent capacity are chosen as simulation system. The results show MEHS system can achieve the best operation result by using the multienergy hybrid generation characteristic. PHSP could shave peak and fill valley of load curve by optimizing pumping storage and inflowing generating behaviors based on the load supply and demand status and the available power of WPP and PV. Robust coefficients can relieve the uncertainty of WPP and PV and provide flexible scheduling decision tools for decision-makers with different risk attitudes by setting different robust coefficients, which could maximize economic benefits and minimize operation risks at the same time.

A Statistical Model for Uplink Intercell Interference with Power Adaptation and Greedy Scheduling

KAUST Repository

Tabassum, Hina

2012-10-03

This paper deals with the statistical modeling of uplink inter-cell interference (ICI) considering greedy scheduling with power adaptation based on channel conditions. The derived model is implicitly generalized for any kind of shadowing and fading environments. More precisely, we develop a generic model for the distribution of ICI based on the locations of the allocated users and their transmit powers. The derived model is utilized to evaluate important network performance metrics such as ergodic capacity, average fairness and average power preservation numerically. Monte-Carlo simulation details are included to support the analysis and show the accuracy of the derived expressions. In parallel to the literature, we show that greedy scheduling with power adaptation reduces the ICI, average power consumption of users, and enhances the average fairness among users, compared to the case without power adaptation. © 2012 IEEE.

A Statistical Model for Uplink Intercell Interference with Power Adaptation and Greedy Scheduling

KAUST Repository

Tabassum, Hina; Yilmaz, Ferkan; Dawy, Zaher; Alouini, Mohamed-Slim

2012-01-01

This paper deals with the statistical modeling of uplink inter-cell interference (ICI) considering greedy scheduling with power adaptation based on channel conditions. The derived model is implicitly generalized for any kind of shadowing and fading environments. More precisely, we develop a generic model for the distribution of ICI based on the locations of the allocated users and their transmit powers. The derived model is utilized to evaluate important network performance metrics such as ergodic capacity, average fairness and average power preservation numerically. Monte-Carlo simulation details are included to support the analysis and show the accuracy of the derived expressions. In parallel to the literature, we show that greedy scheduling with power adaptation reduces the ICI, average power consumption of users, and enhances the average fairness among users, compared to the case without power adaptation. © 2012 IEEE.

Joint Scheduling Optimization of Virtual Power Plants and Equitable Profit Distribution Using Shapely Value Theory

Directory of Open Access Journals (Sweden)

Zhong-fu Tan

2018-01-01

Full Text Available The installation capacity of wind and solar photovoltaic power is continually increasing, which makes renewable energy grid connection and power generation an important link of China’s power structure optimization. A virtual power plant (VPP is an important way to help distributed energy resource grid connection and promote renewable energy industry development. To study the economic scheduling problem of various distributed energy resources and the profit distribution problem of VPP alliance, this study builds a separate operation scheduling model for individual VPP and a joint operation scheduling model for VPP alliance, as well as the profit distribution model. The case study verifies the feasibility and effectiveness of the proposed model. The sensitivity analysis provides information about VPP decision-making in accordance with the policy environment development trend.

One-step hydrothermal synthesis of hexangular starfruit-like vanadium oxide for high power aqueous supercapacitors

Science.gov (United States)

Shao, Jie; Li, Xinyong; Qu, Qunting; Zheng, Honghe

2012-12-01

Homogenous hexangular starfruit-like vanadium oxide was prepared for the first time by a one-step hydrothermal method. The assembly process of hexangular starfruit-like structure was observed from TEM images. The electrochemical performance of starfruit-like vanadium oxide was examined by cyclic voltammetry and galvanostatic charge/discharge. The obtained starfruit-like vanadium oxide exhibits a high power capability (19 Wh kg-1 at the specific power of 3.4 kW kg-1) and good cycling stability for supercapacitors application.

Generation-Side Power Scheduling in a Grid-Connected DC Microgrid

DEFF Research Database (Denmark)

Hernández, Adriana Carolina Luna; Aldana, Nelson Leonardo Diaz; Meng, Lexuan

2015-01-01

In this paper, a constrained mixed-integer programming model for scheduling the active power supplied by the generation units in storage-based DC microgrids is presented. The optimization problem minimizes operating costs taking into account a two-stage mode operation of the energy storage system...... so that a more accurate model for optimization of the microgrid operation can be obtained. The model is used in a particular grid-connected DC microgrid that includes two renewable energy sources and an energy storage system which supply a critical load. The results of the scheduling process...

DAILY SCHEDULING OF SMALL HYDRO POWER PLANTS DISPATCH WITH MODIFIED PARTICLES SWARM OPTIMIZATION

Directory of Open Access Journals (Sweden)

Sinvaldo Rodrigues Moreno

2015-04-01

Full Text Available This paper presents a new approach for short-term hydro power scheduling of reservoirs using an algorithm-based Particle Swarm Optimization (PSO. PSO is a population-based algorithm designed to find good solutions to optimization problems, its characteristics have encouraged its adoption to tackle a variety of problems in different fields. In this paper the authors consider an optimization problem related to a daily scheduling of small hydro power dispatch. The goal is construct a feasible solution that maximize the cascade electricity production, following the environmental constraints and water balance. The paper proposes an improved Particle Swarm Optimization (PSO algorithm, which takes advantage of simplicity and facility of implementation. The algorithm was successfully applied to the optimization of the daily schedule strategies of small hydro power plants, considering maximum water utilization and all constraints related to simultaneous water uses. Extensive computational tests and comparisons with other heuristics methods showed the effectiveness of the proposed approach.

Historical Mass, Power, Schedule, and Cost Growth for NASA Spacecraft

Science.gov (United States)

Hayhurst, Marc R.; Bitten, Robert E.; Shinn, Stephen A.; Judnick, Daniel C.; Hallgrimson, Ingrid E.; Youngs, Megan A.

2016-01-01

Although spacecraft developers have been moving towards standardized product lines as the aerospace industry has matured, NASA's continual need to push the cutting edge of science to accomplish unique, challenging missions can still lead to spacecraft resource growth over time. This paper assesses historical mass, power, cost, and schedule growth for multiple NASA spacecraft from the last twenty years and compares to industry reserve guidelines to understand where the guidelines may fall short. Growth is assessed from project start to launch, from the time of the preliminary design review (PDR) to launch and from the time of the critical design review (CDR) to launch. Data is also assessed not just at the spacecraft bus level, but also at the subsystem level wherever possible, to help obtain further insight into possible drivers of growth. Potential recommendations to minimize spacecraft mass, power, cost, and schedule growth for future missions are also discussed.

Power/performance trade-offs in real-time SDRAM command scheduling

OpenAIRE

Goossens, S.L.M.; Chandrasekar, K.; Akesson, K.B.; Goossens, K.G.W.

2016-01-01

Real-time safety-critical systems should provide hard bounds on an applications’ performance. SDRAM controllers used in this domain should therefore have a bounded worst-case bandwidth, response time, and power consumption. Existing works on real-time SDRAM controllers only consider a narrow range of memory devices, and do not evaluate how their schedulers’ performance varies across memory generations, nor how the scheduling algorithm influences power usage. The extent to which the number of ...

Packet-Scheduling Algorithm by the Ratio of Transmit Power to the Transmission Bits in 3GPP LTE Downlink

Directory of Open Access Journals (Sweden)

Gil Gye-Tae

2010-01-01

Full Text Available Packet scheduler plays the central role in determining the overall performance of the 3GPP long-term evolution (LTE based on packet-switching operation. In this paper, a novel minimum transmit power-based (MP packet-scheduling algorithm is proposed that can achieve power-efficient transmission to the UEs while providing both system throughput gain and fairness improvement. The proposed algorithm is based on a new scheduling metric focusing on the ratio of the transmit power per bit and allocates the physical resource block (PRB to the UE that requires the least ratio of the transmit power per bit. Through computer simulation, the performance of the proposed MP packet-scheduling algorithm is compared with the conventional packet-scheduling algorithms by two primary criteria: fairness and throughput. The simulation results show that the proposed algorithm outperforms the conventional algorithms in terms of the fairness and throughput.

Analysis of Application Power and Schedule Composition in a High Performance Computing Environment

Energy Technology Data Exchange (ETDEWEB)

Elmore, Ryan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gruchalla, Kenny [National Renewable Energy Lab. (NREL), Golden, CO (United States); Phillips, Caleb [National Renewable Energy Lab. (NREL), Golden, CO (United States); Purkayastha, Avi [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wunder, Nick [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-01-05

As the capacity of high performance computing (HPC) systems continues to grow, small changes in energy management have the potential to produce significant energy savings. In this paper, we employ an extensive informatics system for aggregating and analyzing real-time performance and power use data to evaluate energy footprints of jobs running in an HPC data center. We look at the effects of algorithmic choices for a given job on the resulting energy footprints, and analyze application-specific power consumption, and summarize average power use in the aggregate. All of these views reveal meaningful power variance between classes of applications as well as chosen methods for a given job. Using these data, we discuss energy-aware cost-saving strategies based on reordering the HPC job schedule. Using historical job and power data, we present a hypothetical job schedule reordering that: (1) reduces the facility's peak power draw and (2) manages power in conjunction with a large-scale photovoltaic array. Lastly, we leverage this data to understand the practical limits on predicting key power use metrics at the time of submission.

Optimal power system generation scheduling by multi-objective genetic algorithms with preferences

International Nuclear Information System (INIS)

Zio, E.; Baraldi, P.; Pedroni, N.

2009-01-01

Power system generation scheduling is an important issue both from the economical and environmental safety viewpoints. The scheduling involves decisions with regards to the units start-up and shut-down times and to the assignment of the load demands to the committed generating units for minimizing the system operation costs and the emission of atmospheric pollutants. As many other real-world engineering problems, power system generation scheduling involves multiple, conflicting optimization criteria for which there exists no single best solution with respect to all criteria considered. Multi-objective optimization algorithms, based on the principle of Pareto optimality, can then be designed to search for the set of nondominated scheduling solutions from which the decision-maker (DM) must a posteriori choose the preferred alternative. On the other hand, often, information is available a priori regarding the preference values of the DM with respect to the objectives. When possible, it is important to exploit this information during the search so as to focus it on the region of preference of the Pareto-optimal set. In this paper, ways are explored to use this preference information for driving a multi-objective genetic algorithm towards the preferential region of the Pareto-optimal front. Two methods are considered: the first one extends the concept of Pareto dominance by biasing the chromosome replacement step of the algorithm by means of numerical weights that express the DM' s preferences; the second one drives the search algorithm by changing the shape of the dominance region according to linear trade-off functions specified by the DM. The effectiveness of the proposed approaches is first compared on a case study of literature. Then, a nonlinear, constrained, two-objective power generation scheduling problem is effectively tackled

Scheduled power tracking control of the wind-storage hybrid system based on the reinforcement learning theory

Science.gov (United States)

Li, Ze

2017-09-01

In allusion to the intermittency and uncertainty of the wind electricity, energy storage and wind generator are combined into a hybrid system to improve the controllability of the output power. A scheduled power tracking control method is proposed based on the reinforcement learning theory and Q-learning algorithm. In this method, the state space of the environment is formed with two key factors, i.e. the state of charge of the energy storage and the difference value between the actual wind power and scheduled power, the feasible action is the output power of the energy storage, and the corresponding immediate rewarding function is designed to reflect the rationality of the control action. By interacting with the environment and learning from the immediate reward, the optimal control strategy is gradually formed. After that, it could be applied to the scheduled power tracking control of the hybrid system. Finally, the rationality and validity of the method are verified through simulation examples.

Application exploration of primavera6.0 for design-schedule in nuclear power station

International Nuclear Information System (INIS)

Zhang Xiaoping

2009-01-01

The ideas and flow of plan establishment during the nuclear power station design is discussed in this paper, including the main steps in the plan establishment, and the design schedule and the management of documents and interfaces are improved. An integral design management innovation is proposed for the management of 'schedule, interfaces and drawings and files'. (authors)

A Work-Demand Analysis Compatible with Preemption-Aware Scheduling for Power-Aware Real-Time Tasks

Directory of Open Access Journals (Sweden)

Da-Ren Chen

2013-01-01

Full Text Available Due to the importance of slack time utilization for power-aware scheduling algorithms,we propose a work-demand analysis method called parareclamation algorithm (PRA to increase slack time utilization of the existing real-time DVS algorithms. PRA is an online scheduling for power-aware real-time tasks under rate-monotonic (RM policy. It can be implemented and fully compatible with preemption-aware or transition-aware scheduling algorithms without increasing their computational complexities. The key technique of the heuristics method doubles the analytical interval and turns the deferrable workload out the potential slack time. Theoretical proofs show that PRA guarantees the task deadlines in a feasible RM schedule and takes linear time and space complexities. Experimental results indicate that the proposed method combining the preemption-aware methods seamlessly reduces the energy consumption by 14% on average over their original algorithms.

A long-term optimization method for reservoir management in a market oriented hydro-dominated power systems

International Nuclear Information System (INIS)

Sultovic, E.; Sarajcev, I.; Majstrovic, M.

2001-01-01

This paper presents an optimization-based method for the long-term scheduling of hydrothermal power system. The proposed method maximizes the profit of hydroelectric production in power system based on monthly energy requirement of the system and unit commitment calculations. The method allows precise hydro chain modeling with numerous restrictions as well as computation for multiple-reservoir river systems with multiple-purpose operation. The method has been implemented in a computer program and tested on power system, which is very similar to Croatian Power System in the year 2000. Several testing results are given. Presented method can be applicable for long-term planning in a competitive electricity market due to possibility of unit commitment calculations with different electrical energy price during scheduling horizon. (authors)

Scheduling of power generation a large-scale mixed-variable model

CERN Document Server

Prékopa, András; Strazicky, Beáta; Deák, István; Hoffer, János; Németh, Ágoston; Potecz, Béla

2014-01-01

The book contains description of a real life application of modern mathematical optimization tools in an important problem solution for power networks. The objective is the modelling and calculation of optimal daily scheduling of power generation, by thermal power plants,  to satisfy all demands at minimum cost, in such a way that the  generation and transmission capacities as well as the demands at the nodes of the system appear in an integrated form. The physical parameters of the network are also taken into account. The obtained large-scale mixed variable problem is relaxed in a smart, practical way, to allow for fast numerical solution of the problem.

Synthesis of high intrinsic loss power aqueous ferrofluids of iron oxide nanoparticles by citric acid-assisted hydrothermal-reduction route

International Nuclear Information System (INIS)

Behdadfar, Behshid; Kermanpur, Ahmad; Sadeghi-Aliabadi, Hojjat; Morales, Maria del Puerto; Mozaffari, Morteza

2012-01-01

Monodispersed aqueous ferrofluids of iron oxide nanoparticle were synthesized by hydrothermal-reduction route. They were characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy and dynamic light scattering. The results showed that certain concentrations of citric acid (CA) are required to obtain only magnetic iron oxides with mean particle sizes around 8 nm. CA acts as a modulator and reducing agent in iron oxide formation which controls nanoparticle size. The XRD, magnetic and heating measurements showed that the temperature and time of hydrothermal reaction can affect the magnetic properties of obtained ferrofluids. The synthesized ferrofluids were stable at pH 7. Their mean hydrodynamic size was around 80 nm with polydispersity index (PDI) of 0.158. The calculated intrinsic loss power (ILP) was 9.4 nHm 2 /kg. So this clean and cheap route is an efficient way to synthesize high ILP aqueous ferrofluids applicable in magnetic hyperthermia. - Graphical abstract: Monodispersed aqueous ferrofluids of iron oxide nanoparticles were synthesized by hydrothermal-reduction method with citric acid as reductant which is an efficient way to synthesize aqueous ferrofluids applicable in magnetic hyperthermia. Highlights: ► Aqueous iron oxide ferrofluids were synthesized by hydrothermal-reduction route. ► Citric acid acted as reducing agent and surfactant in the route. ► This is a facile, low energy and environmental friendly route. ► The aqueous iron oxide ferrofluids were monodispersed and stable at pH of 7. ► The calculated intrinsic loss power of the synthesized ferrofluids was very high.

Power Saving Scheduling Scheme for Internet of Things over LTE/LTE-Advanced Networks

Directory of Open Access Journals (Sweden)

Yen-Wei Kuo

2015-01-01

Full Text Available The devices of Internet of Things (IoT will grow rapidly in the near future, and the power consumption and radio spectrum management will become the most critical issues in the IoT networks. Long Term Evolution (LTE technology will become a promising technology used in IoT networks due to its flat architecture, all-IP network, and greater spectrum efficiency. The 3rd Generation Partnership Project (3GPP specified the Discontinuous Reception (DRX to reduce device’s power consumption. However, the DRX may pose unexpected communication delay due to missing Physical Downlink Control Channel (PDCCH information in sleep mode. Recent studies mainly focus on optimizing DRX parameters to manage the tradeoff between the energy consumption and communication latency. In this paper, we proposed a fuzzy-based power saving scheduling scheme for IoT over the LTE/LTE-Advanced networks to deal with the issues of the radio resource management and power consumption from the scheduling and resource allocation perspective. The proposed scheme considers not only individual IoT device’s real-time requirement but also the overall network performance. The simulation results show that our proposed scheme can meet the requirements of the DRX cycle and scheduling latency and can save about half of energy consumption for IoT devices compared to conventional approaches.

An efficient chaos embedded hybrid approach for hydro-thermal unit commitment problem

International Nuclear Information System (INIS)

Yuan, Xiaohui; Ji, Bin; Yuan, Yanbin; Ikram, Rana M.; Zhang, Xiaopan; Huang, Yuehua

2015-01-01

Highlights: • Thermal unit commitment is considered in hydrothermal generation scheduling (SHTGS). • Two newly proposed promising optimization algorithms are combined to solving SHTGS. • The proposed method is enhanced by integrating a chaotic local search strategy. • Heuristic search strategies are applied to handle the constraints of the SHTGS. • The results verify the proposed method is feasible and efficient for handling SHTGS. - Abstract: This paper establishes a model to deal with the short-term hydrothermal generation scheduling (SHTGS) problem. The problem is composed of three interconnected parts: short-term hydrothermal coordination, thermal unit commitment and economic load dispatch. An efficient hybrid method composed of chaotic backtracking search optimization algorithm and binary charged system search algorithm (CBSA–BCSS) is proposed to solve this problem. In order to analyze the effect of the chaotic map on the performance of the method, three different chaotic maps are adopted to integrate into the proposed method and the corresponding consequences are achieved. Furthermore, efficient heuristic search strategies are adopted to handle with the complicated constraints of the SHTGS system. Finally, a hydrothermal unit commitment system is utilized to verify the feasibility and effectiveness of the proposed method. The results demonstrate the efficiency of the hybrid optimization method and the appropriation of the constraint handling strategies. The comparison of the solutions achieved by different methods shows that the proposed method has higher efficiency in terms of solving SHTGS problem

Contribution to the operating energy planning of hydrothermal power systems; Contribuicao ao planejamento da operacao energetica de sistemas hidrotermicos de potencia

Energy Technology Data Exchange (ETDEWEB)

Carneiro, Adriano Alber de Franca Mendes

1991-08-01

This work treats of the problem of the planning of the energy operation of hydrothermal power systems, gone back to those with predominance of hydraulic generation, as it is the case of the Brazilian system. The work makes an analysis of the problem of the planning of the energy operation of systems hydrothermal leaving of the concepts and nature of this problem. Their inherent difficulties are shown and they come the main approaches in operation in countries with predominance of hydroelectric generation. It still introduces the methodology in energy planning in Brazil being pointed their main limitations. Finally an alternative model for the planning of the energy operation of the system brazilian hydrothermal, based on the made studies is also presented.

Stochastic multiobjective self-scheduling of a power producer in joint energy and reserves markets

International Nuclear Information System (INIS)

Vahidinasab, V.; Jadid, S.

2010-01-01

This paper presents a stochastic multiobjective model for self-scheduling of a power producer which participates in the day-ahead joint energy and reserves markets. The objective of a power producer is to compromise the conflicting objectives of payoff maximization and gaseous emissions minimization when committing its generation of thermal units. The proposed schedule will be used by the power producers to decide on emission quota arbitrage opportunities and for strategic bidding to the energy and reserves market. The paper analyzes a scenario-based multiobjective model in which random distributions, such as price forecasting inaccuracies as well as forced outage of generating units are modeled as scenarios tree using a combined fuzzy c-mean/Monte-Carlo simulation (FCM/MCS) method. With the above procedure the stochastic multiobjective self-scheduling problem is converted into corresponding deterministic problems. Then a multiobjective mathematical programming (MMP) approach based on ε-constraint method is implemented for each deterministic scenario. Piecewise linearized fuel and emission cost functions are applied for computational efficiency and the model is formulated as a mixed-integer programming (MIP) problem. Numerical simulations for a power producer with 21 thermal units are discussed to demonstrate the performance of the proposed approach in increasing expected payoffs by adjusting the emission quota arbitrage opportunities. (author)

Scheduling and coordination for in-service inspection of nuclear power plant

International Nuclear Information System (INIS)

Li Songbai

1996-11-01

Based on the practice and experiences of pre-service and in-service inspections for Daya Bay Nuclear Power Plant (NPP) by Research Institute of Nuclear Power Operation (RINPO) following RSEM code, requirements of utility and actual situation in China, the in-service inspection preparation for organization, techniques and equipment/tooling, materials, personnel and documentation is briefly described. And the scheduling and coordinating consideration for planed in-service inspection activities during NPP outage is emphatically introduced. (2 refs., 4 figs.)

A new self-scheduling strategy for integrated operation of wind and pumped-storage power plants in power markets

International Nuclear Information System (INIS)

Varkani, Ali Karimi; Daraeepour, Ali; Monsef, Hassan

2011-01-01

Highlights: → A strategy for integrated operation of wind and pumped-storage plants is proposed. → Participation of both plants in energy and ancillary service markets is modeled. → The uncertainty of wind production is modeled by a novel probabilistic function. → The proposed strategy is tested on a real case in the Spanish electricity market. -- Abstract: Competitive structure of power markets causes various challenges for wind resources to participate in these markets. Indeed, production uncertainty is the main cause of their low income. Thus, they are usually supported by system operators, which is in contrast with the competitive paradigm of power markets. In this paper, a new strategy for increasing the profits of wind resources is proposed. In the suggested strategy, a Generation Company (GenCo), who owns both wind and pumped-storage plants, self-schedules the integrated operation of them regarding the uncertainty of wind power generation. For presenting an integrated self-schedule and obtaining a real added value of the strategy, participation of the GenCo in energy and ancillary service markets is modeled. The self-scheduling strategy is based on stochastic programming techniques. Outputs of the problem include generation offers in day-ahead energy market and ancillary service markets, including spinning and regulation reserve markets. A Neural Network (NN) based technique is used for modeling the uncertainty of wind power production. The proposed strategy is tested on a real wind farm in mainland, Spain. Moreover, added value of the strategy is presented in different conditions of the market.

Modeling the transient security constraints of natural gas network in day-ahead power system scheduling

DEFF Research Database (Denmark)

Yang, Jingwei; Zhang, Ning; Kang, Chongqing

2017-01-01

The rapid deployment of gas-fired generating units makes the power system more vulnerable to failures in the natural gas system. To reduce the risk of gas system failure and to guarantee the security of power system operation, it is necessary to take the security constraints of natural gas...... accurately, they are hard to be embedded into the power system scheduling model, which consists of algebraic equations and inequations. This paper addresses this dilemma by proposing an algebraic transient model of natural gas network which is similar to the branch-node model of power network. Based...... pipelines into account in the day-ahead power generation scheduling model. However, the minute- and hour-level dynamic characteristics of gas systems prevents an accurate decision-making simply with the steady-state gas flow model. Although the partial differential equations depict the dynamics of gas flow...

Modeling and simulation of the power demand and supply of a hydrothermal power generating system

International Nuclear Information System (INIS)

Pronini, R.A.

1996-01-01

Security of supply of electric energy is measured by the capacity to cover the energy demand and power of a supply grid. This coverage is important because the winter peak load period in Switzerland will become problematical in the near future. The objective of this research project is to analyze the ability of a power generating system to satisfy the power requirements of the corresponding supply network. The behaviour of the energy system in critical cases (loss of the largest generator, lack of available power from an external supplier or reduced capacity for energy storage) is tested for the present situation and for the rise in the annual load. The simulation of the load of the supply network is carried out by using a model developed for this project. This model is based on the analysis of half-hourly changes of load and on the statistical maximum values. The power generating system consists of nuclear generating units, hydro units with large reservoirs, run of the river installations and imported energy. Standby units such as gas turbines, spot market and coal-fired power stations are also available. Stochastic and deterministic energy and power models have been developed for the various power stations of the hydrothermal power system. In the case of nuclear power stations, a model has been developed on the basis of the output level, production losses and time and length of outages. The possible feeder streams of the run of the river installations and of the hydro units with a large reservoir are simulated using stochastic methods based on the historical values of the last 35 years. The commitment of the hydro units depends on the peak load requirements. The load and capacity over a period of several days and weeks have been simulated with stochastic models based on the Monte Carlo method and constantly (by half hour intervals) compared. In this manner each month can be simulated. (author) figs., tabs., 46 refs

Stochastic profit-based scheduling of industrial virtual power plant using the best demand response strategy

International Nuclear Information System (INIS)

Nosratabadi, Seyyed Mostafa; Hooshmand, Rahmat-Allah; Gholipour, Eskandar

2016-01-01

Highlights: • VPPs and IVPPs are defined for energy management of aggregated generations. • IVPP can manage industrial microgrid containing some relevant load and generation. • A stochastic modeling is proposed to schedule optimal generations in competition market. • Wind generation and day-ahead and spot market prices are considered to be stochastic. • A new DRL program selection scheme is presented in the scheduling procedure. - Abstract: One of the main classified microgrids in a power system is the industrial microgrid. Due to its behaviors and the heavy loads, its energy management is challengeable. Virtual Power Plant (VPP) can be an important concept in managing such problems in this kind of grids. Here, a transmission power system is considered as a Regional Electric Company (REC) and the VPPs comprising Distributed Generation (DG) units and Demand Response Loads (DRLs) are determined in this system. This paper focuses on Industrial VPP (IVPP) and its management. An IVPP can be determined as a management unit comprising generations and loads in an industrial microgrid. Since the scheduling procedure for these units is very important for their participation in a short-term electric market, a stochastic formulation is proposed for power scheduling in VPPs especially in IVPPs in this paper. By introducing the DRL programs and using the proposed modeling, the operator can select the best DRL program for each VPP in a scheduling procedure. In this regard, a suitable approach is presented to determine the proposed formulation and its solution in a Mixed Integer Non-Linear Programming (MINLP). To validate the performance of the proposed method, the IEEE Reliability Test System (IEEE-RTS) is considered to apply the method on it, while some challenging aspects are presented.

Systematic Evaluation of Stochastic Methods in Power System Scheduling and Dispatch with Renewable Energy

Energy Technology Data Exchange (ETDEWEB)

Wang, Yishen [Univ. of Washington, Seattle, WA (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Zhou, Zhi [Argonne National Lab. (ANL), Argonne, IL (United States); Liu, Cong [Argonne National Lab. (ANL), Argonne, IL (United States); Electric Reliability Council of Texas (ERCOT), Austin, TX (United States); Botterud, Audun [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-08-01

As more wind power and other renewable resources are being integrated into the electric power grid, the forecast uncertainty brings operational challenges for the power system operators. In this report, different operational strategies for uncertainty management are presented and evaluated. A comprehensive and consistent simulation framework is developed to analyze the performance of different reserve policies and scheduling techniques under uncertainty in wind power. Numerical simulations are conducted on a modified version of the IEEE 118-bus system with a 20% wind penetration level, comparing deterministic, interval, and stochastic unit commitment strategies. The results show that stochastic unit commitment provides a reliable schedule without large increases in operational costs. Moreover, decomposition techniques, such as load shift factor and Benders decomposition, can help in overcoming the computational obstacles to stochastic unit commitment and enable the use of a larger scenario set to represent forecast uncertainty. In contrast, deterministic and interval unit commitment tend to give higher system costs as more reserves are being scheduled to address forecast uncertainty. However, these approaches require a much lower computational effort Choosing a proper lower bound for the forecast uncertainty is important for balancing reliability and system operational cost in deterministic and interval unit commitment. Finally, we find that the introduction of zonal reserve requirements improves reliability, but at the expense of higher operational costs.

Hydrogen is an energy source for hydrothermal vent symbioses.

Science.gov (United States)

Petersen, Jillian M; Zielinski, Frank U; Pape, Thomas; Seifert, Richard; Moraru, Cristina; Amann, Rudolf; Hourdez, Stephane; Girguis, Peter R; Wankel, Scott D; Barbe, Valerie; Pelletier, Eric; Fink, Dennis; Borowski, Christian; Bach, Wolfgang; Dubilier, Nicole

2011-08-10

The discovery of deep-sea hydrothermal vents in 1977 revolutionized our understanding of the energy sources that fuel primary productivity on Earth. Hydrothermal vent ecosystems are dominated by animals that live in symbiosis with chemosynthetic bacteria. So far, only two energy sources have been shown to power chemosynthetic symbioses: reduced sulphur compounds and methane. Using metagenome sequencing, single-gene fluorescence in situ hybridization, immunohistochemistry, shipboard incubations and in situ mass spectrometry, we show here that the symbionts of the hydrothermal vent mussel Bathymodiolus from the Mid-Atlantic Ridge use hydrogen to power primary production. In addition, we show that the symbionts of Bathymodiolus mussels from Pacific vents have hupL, the key gene for hydrogen oxidation. Furthermore, the symbionts of other vent animals such as the tubeworm Riftia pachyptila and the shrimp Rimicaris exoculata also have hupL. We propose that the ability to use hydrogen as an energy source is widespread in hydrothermal vent symbioses, particularly at sites where hydrogen is abundant.

Optimal scheduling of biocide dosing for seawater-cooled power and desalination plants

KAUST Repository

Mahfouz, Abdullah Bin

2011-02-13

Thermal desalination systems are typically integrated with power plants to exploit the excess heat resulting from the power-generation units. Using seawater in cooling the power plant and the desalination system is a common practice in many parts of the world where there is a shortage of freshwater. Biofouling is one of the major problems associated with the usage of seawater in cooling systems. Because of the dynamic variation in the power and water demands as well as the changes in the characteristics of seawater and the process, there is a need to develop an optimal policy for scheduling biocide usage and cleaning maintenance of the heat exchangers. The objective of this article is to introduce a systematic procedure for the optimization of scheduling the dosing of biocide and dechlorination chemicals as well as cleaning maintenance for a power production/thermal desalination plant. A multi-period optimization formulation is developed and solved to determine: the optimal levels of dosing and dechlorination chemicals; the timing of maintenance to clean the heat-exchange surfaces; and the dynamic dependence of the biofilm growth on the applied doses, the seawater-biocide chemistry, the process conditions, and seawater characteristics for each time period. The technical, economic, and environmental considerations of the system are accounted for. A case study is solved to elucidate the applicability of the developed optimization approach. © 2011 Springer-Verlag.

Electromagnetic interference-aware transmission scheduling and power control for dynamic wireless access in hospital environments.

Science.gov (United States)

Phunchongharn, Phond; Hossain, Ekram; Camorlinga, Sergio

2011-11-01

We study the multiple access problem for e-Health applications (referred to as secondary users) coexisting with medical devices (referred to as primary or protected users) in a hospital environment. In particular, we focus on transmission scheduling and power control of secondary users in multiple spatial reuse time-division multiple access (STDMA) networks. The objective is to maximize the spectrum utilization of secondary users and minimize their power consumption subject to the electromagnetic interference (EMI) constraints for active and passive medical devices and minimum throughput guarantee for secondary users. The multiple access problem is formulated as a dual objective optimization problem which is shown to be NP-complete. We propose a joint scheduling and power control algorithm based on a greedy approach to solve the problem with much lower computational complexity. To this end, an enhanced greedy algorithm is proposed to improve the performance of the greedy algorithm by finding the optimal sequence of secondary users for scheduling. Using extensive simulations, the tradeoff in performance in terms of spectrum utilization, energy consumption, and computational complexity is evaluated for both the algorithms.

Combined scheduling of electricity and heat in a microgrid with volatile wind power

DEFF Research Database (Denmark)

Xu, Lizhong; Yang, Guang Ya; Xu, Zhao

2011-01-01

An optimization model is developed for scheduling electricity and heat production in a microgrid under a day-ahead market environment considering the operation constraints and the volatility of wind power generation. The model optimizes the total operation costs from energy and heating consumption...... into a mixed-integer programming (MIP) problem. Numerical simulations present the efficacy of the proposed model for day-ahead scheduling of a microgrid with wind penetration under the deregulated environment. © 2011 State Grid Electrtic Resarch Institute Press....

Economic-environmental active and reactive power scheduling of modern distribution systems in presence of wind generations: A distribution market-based approach

International Nuclear Information System (INIS)

Samimi, Abouzar; Kazemi, Ahad; Siano, Pierluigi

2015-01-01

Highlights: • A new market-based approach is proposed to schedule active and reactive powers. • Multi-component reactive power bidding structures for DERs is introduced. • A new economical/environmental operational scheduling method is proposed. • At distribution level, a reactive power market is developed in presence of DERs. - Abstract: Distribution System Operator (DSO) is responsible for active and reactive power scheduling in a distribution system. DSO purchases its active and reactive power requirements from Distributed Energy Resources (DERs) as well as the wholesale electricity market. In this paper, a new economical/environmental operational scheduling method based on sequential day-ahead active and reactive power markets at distribution level is proposed to dispatch active and reactive powers in distribution systems with high penetration of DERs. In the proposed model, after day-ahead active power market was cleared the participants submit their reactive power bids and then the reactive power market will be settled. At distribution level, developing a Var market, in which DERs like synchronous machine-based Distributed Generation (DG) units and Wind Turbines (WTs) could offer their reactive power prices, DERs are motivated to actively participate in the Volt/VAr Control (VVC) problem. To achieve this purpose, based on the capability curves of considered DERs, innovative multi-component reactive power bidding structures for DERs are introduced. Moreover, the effect of reactive power market clearing on the active power scheduling is explicitly considered into the proposed model by rescheduling of active power by usage of energy-balance service bids. On the other hand, environmental concerns that arise from the operation of fossil fuel fired electric generators are included in the proposed model by employing CO_2 emission penalty cost. The suggested reactive power market is cleared through a mixed-integer nonlinear optimization program. The

Hydrothermal processes above the Yellowstone magma chamber: Large hydrothermal systems and large hydrothermal explosions

Science.gov (United States)

Morgan, L.A.; Shanks, W.C. Pat; Pierce, K.L.

2009-01-01

Hydrothermal explosions are violent and dramatic events resulting in the rapid ejection of boiling water, steam, mud, and rock fragments from source craters that range from a few meters up to more than 2 km in diameter; associated breccia can be emplaced as much as 3 to 4 km from the largest craters. Hydrothermal explosions occur where shallow interconnected reservoirs of steam- and liquid-saturated fluids with temperatures at or near the boiling curve underlie thermal fields. Sudden reduction in confi ning pressure causes fluids to fl ash to steam, resulting in signifi cant expansion, rock fragmentation, and debris ejection. In Yellowstone, hydrothermal explosions are a potentially signifi cant hazard for visitors and facilities and can damage or even destroy thermal features. The breccia deposits and associated craters formed from hydrothermal explosions are mapped as mostly Holocene (the Mary Bay deposit is older) units throughout Yellowstone National Park (YNP) and are spatially related to within the 0.64-Ma Yellowstone caldera and along the active Norris-Mammoth tectonic corridor. In Yellowstone, at least 20 large (>100 m in diameter) hydrothermal explosion craters have been identifi ed; the scale of the individual associated events dwarfs similar features in geothermal areas elsewhere in the world. Large hydrothermal explosions in Yellowstone have occurred over the past 16 ka averaging ??1 every 700 yr; similar events are likely in the future. Our studies of large hydrothermal explosion events indicate: (1) none are directly associated with eruptive volcanic or shallow intrusive events; (2) several historical explosions have been triggered by seismic events; (3) lithic clasts and comingled matrix material that form hydrothermal explosion deposits are extensively altered, indicating that explosions occur in areas subjected to intense hydrothermal processes; (4) many lithic clasts contained in explosion breccia deposits preserve evidence of repeated fracturing

Schedule and staffing of a nuclear power project

International Nuclear Information System (INIS)

Polliart, A.J.; Csik, B.

1977-01-01

Establishment of construction schedule: a) preliminary construction schedule; b) PERT (Program Evaluation Review Techniques) analytical method; c) identify key milestone target dates; d) inter-action by participants and contribution to support revised construction schedule. - Construction schedule control: a) ability to update and modify construction schedule; b) alternate plans to circumvent restraints (problems); c) critical path activity-controls; d) continuous review and report system. - Updating construction site reports to include: 1) progress, 2) accomplishments, 3) potential problems and alternate plans; b) progress reports on related support services; c) total assessment of participating groups on schedule; d) information required by management for decisions. - Typical causes for delays in project schedule. (orig.) [de

To Problem Pertaining to Provision of Electric Power Load Schedules of Power Sys- tems while Involving Potential of Power Technological Sources of Industrial Enterprises

Directory of Open Access Journals (Sweden)

B. M. Khroustalev

2010-01-01

Full Text Available The paper considers a possibility to use co-generated complexes having heat technological industrial load for operation in accordance with the requirements of irregularity of electric power generation schedule.

Energy models for generation planning and midterm operation of hydrothermal power systems

Energy Technology Data Exchange (ETDEWEB)

Amthauer, E

1981-01-01

The aims of generation planning and midterm operation of a power system are reliable and economical load coverage at any moment. For solving some of the planning tasks, it is advantageous to use energy models, if a large amount of power is installed in hydro-storage plants. Energy models apply the probability of load coverage in a given period as a quantitative measure for a power system's reliability provided the availability of the transmission network is given. Reliability may be influenced by installing new plants (longterm) or by committing the existing plants in a particular fashion. An evaluation of these activities makes it possible to determine decisions which optimize a given object function. In this thesis, energy models for the Swiss hydrothermal power system are derived and tested by simulation. For this utility, energy supply during the emptying period of the storage plants in winter is of special interest. Therefore, the criteria for generation planning are derived by analysing the distribution functions of future energy balances in winter periods. The committment of the existing plants and energy exchange with other utilities in a straight following winter period are planned by means of a sequential decision process. It is shown how strategies for these planning tasks are found with the models. Those model parameters, having the highest influence on reliable and economical load coverage are extracted by means of sensitivity analysis.

Collaborative Scheduling between OSPPs and Gasholders in Steel Mill under Time-of-Use Power Price

Directory of Open Access Journals (Sweden)

Juxian Hao

2017-08-01

Full Text Available Byproduct gases generated during steel production process are the main fuels for on-site power plants (OSPPs in steel enterprises. Recently, with the implementation of time-of-use (TOU power price in China, increasing attention has been paid to the collaborative scheduling between OSPPs and gasholders. However, the load shifting potential of OSPPs has seldom been discussed in previous studies. In this paper, a mixed integer linear programming (MILP-based scheduling model is built to evaluate the load shifting potential and the corresponding economic benefits. A case study is conducted on two steel enterprises with different configurations of OSPPs, and the optimal operation strategy is also discussed.

A Systematical Framework of Schedule Risk Management for Power Grid Engineering Projects’ Sustainable Development

Directory of Open Access Journals (Sweden)

Rao Rao

2014-10-01

Full Text Available Schedule risks are the main threat for high efficiency of schedule management in power grid engineering projects (PGEP. This paper aims to build a systematical framework for schedule risk management, which consists of three dimensions, including the personnel dimension, method dimension and time dimension, namely supervisory personnel, management methods and the construction process, respectively. Responsibilities of staff with varied functions are discussed in the supervisory personnel part, and six stages and their corresponding 40 key works are ensured as the time dimension. Risk identification, analysis, evaluation and prevention together formed the method dimension. Based on this framework, 222 schedule risks occur in the whole process of PGEPs are identified via questionnaires and expert interviews. Then, the relationship among each risk is figured out based on the Interpretative Structure Model (ISM method and the impact of each risk is quantitatively assessed by establishing evaluation system. The actual practice of the proposed framework is verified through the analysis of the first stage of a PGEP. Finally, the results show that this framework of schedule risk management is meaningful for improving the efficiency of project management. It provides managers with a clearer procedure with which to conduct risk management, helps them to timely detect risks and prevent risks from occurring. It is also easy for managers to judge the influence level of each risk, so they can take actions based on the level of each risk’s severity. Overall, it is beneficial for power grid enterprises to achieve a sustainable management.

Automatic generation control of an interconnected hydrothermal power system considering superconducting magnetic energy storage

Energy Technology Data Exchange (ETDEWEB)

Abraham, Rajesh Joseph; Das, D.; Patra, Amit [Department of Electrical Engineering, Indian Institute of Technology, Kharagpur 721 302 (India)

2007-10-15

This paper presents the analysis of automatic generation control (AGC) of an interconnected hydrothermal power system in the presence of generation rate constraints (GRCs). The improvement of AGC with the addition of a small capacity superconducting magnetic energy storage (SMES) unit in either, as well as in both the areas are studied. Time domain simulations are used to study the performance of the power system and control logic. The optimal values of the integral gain settings are obtained using integral squared error (ISE) technique by minimising a quadratic performance index. Suitable method for controlling the SMES unit is described. Analysis reveals that SMES unit fitted in either of the areas is as effective as SMES units fitted in both the areas and improves the dynamic performances to a considerable extent following a load disturbance in either of the areas. (author)

A Heuristic Approach for Determining Lot Sizes and Schedules Using Power-of-Two Policy

Directory of Open Access Journals (Sweden)

Esra Ekinci

2007-01-01

Full Text Available We consider the problem of determining realistic and easy-to-schedule lot sizes in a multiproduct, multistage manufacturing environment. We concentrate on a specific type of production, namely, flow shop type production. The model developed consists of two parts, lot sizing problem and scheduling problem. In lot sizing problem, we employ binary integer programming and determine reorder intervals for each product using power-of-two policy. In the second part, using the results obtained of the lot sizing problem, we employ mixed integer programming to determine schedules for a multiproduct, multistage case with multiple machines in each stage. Finally, we provide a numerical example and compare the results with similar methods found in practice.

Nuclear Power Plant Preventive Maintenance Scheduling Problem with Fuzziness

International Nuclear Information System (INIS)

Abass, S.A.; Abdallah, A.S.

2013-01-01

Maintenance activity is regarded as the most important key factor for the safety, reliability and economy of a nuclear power plant. Preventive maintenance refers to set of planned activities which include nondestructive testing and periodic inspection as well as maintenance. In this paper, we address the problem of nuclear power plant preventive maintenance scheduling with uncertainty. The uncertainty will be represented by fuzzy parameters. The problem is how to determine the period for which generating units of an electric system should be taken off line for planned preventive maintenance over specific time horizon. Preventive maintenance activity of a nuclear power plant is an important issue as it designed to extend the plant life . It is more required to review the maintenance not only from the view point of safety and reliability but also economy. Preventive maintenance program exists to ensure that nuclear safety significant equipment will function when it is supposed to. Also this problem is extremely important because a failure in a power plant may cause a general breakdown in an electric network. In this paper a mixed integer programming model is used to express this problem. In proposed model power demand is taken as fuzzy parameters. A case study is provided to demonstrate the efficiency of the proposed model.

Short term hydroelectric power system scheduling with wind turbine generators using the multi-pass iteration particle swarm optimization approach

International Nuclear Information System (INIS)

Lee, T.-Y.

2008-01-01

This paper uses multi-pass iteration particle swarm optimization (MIPSO) to solve short term hydroelectric generation scheduling of a power system with wind turbine generators. MIPSO is a new algorithm for solving nonlinear optimal scheduling problems. A new index called iteration best (IB) is incorporated into particle swarm optimization (PSO) to improve solution quality. The concept of multi-pass dynamic programming is applied to modify PSO further and improve computation efficiency. The feasible operational regions of the hydro units and pumped storage plants over the whole scheduling time range must be determined before applying MIPSO to the problem. Wind turbine power generation then shaves the power system load curves. Next, MIPSO calculates hydroelectric generation scheduling. It begins with a coarse time stage and searching space and refines the time interval between two time stages and the search spacing pass by pass (iteration). With the cooperation of agents called particles, the near optimal solution of the scheduling problem can be effectively reached. The effects of wind speed uncertainty were also considered in this paper. The feasibility of the new algorithm is demonstrated by a numerical example, and MIPSO solution quality and computation efficiency are compared to those of other algorithms

An Optimization Scheduling Model for Wind Power and Thermal Power with Energy Storage System considering Carbon Emission Trading

Directory of Open Access Journals (Sweden)

Huan-huan Li

2015-01-01

Full Text Available Wind power has the characteristics of randomness and intermittence, which influences power system safety and stable operation. To alleviate the effect of wind power grid connection and improve power system’s wind power consumptive capability, this paper took emission trading and energy storage system into consideration and built an optimization model for thermal-wind power system and energy storage systems collaborative scheduling. A simulation based on 10 thermal units and wind farms with 2800 MW installed capacity verified the correctness of the models put forward by this paper. According to the simulation results, the introduction of carbon emission trading can improve wind power consumptive capability and cut down the average coal consumption per unit of power. The introduction of energy storage system can smooth wind power output curve and suppress power fluctuations. The optimization effects achieve the best when both of carbon emission trading and energy storage system work at the same time.

Inclusion of environmental costs on a long-term expansion model of hydrothermal generation systems; Insercao dos custos ambientais em um modelo de expansao da geracao a longo prazo

Energy Technology Data Exchange (ETDEWEB)

Santos Henrique Luz

2008-02-15

This dissertation presents the development of a mathematical model to be used in the hydrothermal generation expansion planning taking into account uncertainties, the guarantee of energy supply and issues related to the social and environmental problems caused by the power sector. Named 'MELP Ambiental', it is a version of MELP, a model developed by Machado Junior (2000). The environmental valuation was based on results of previous studies. The analysis of the environmental costs scenarios showed that the inclusion of a variable linked to externalities implies in changes on the investment schedule. These changes decrease the total cost (economic and environmental) related to long-term power supply expansion. (author)

FY 2000 report on the development of hydrothermal use power plant, etc. Development of the binary cycle power plant (Development of a 10MW class plant); 2000 nendo Nessui riyo hatsuden plant tou kaihatsu. Bainari cycle hatsuden plant no kaihatsu - 10MW kyu plant no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-01-01

For the purpose of developing a 10MW class demonstrative plant for geothermal binary power generation, the R and D were carried out, and the results obtained from FY 1995 to FY 1999 were summed up. In the interim evaluation made in July 1994, study was to be phasedly proceeded with for the main three systems (hydrothermal system, medium system and power generation system) which compose the 10MW class binary cycle power plant. The test on the hydrothermal system was started in FY 1995. In the R and D, the following were conducted for evaluation: design/manufacture/installation of the test device for the hydrothermal system, manufacture of demonstrative downhole pump (DHP) No.3 and test at plant, test on the hydrothermal system. As to the turbine working medium suitable for binary power plant, the specified freon/substitute freon have been used, but it seems that hydrocarbons such as butane and pentane can be effective in future. In the study of the economical efficiency, it was pointed out that for the commercialization, it is important to improve durability of DHP and further reduce the cost of DHP equipment and cost of repairs. (NEDO)

Constraint-based scheduling

Science.gov (United States)

Zweben, Monte

1993-01-01

The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint-based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all the inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocation for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its application to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.

Optimization-based sale transactions and hydrothermal scheduling

International Nuclear Information System (INIS)

Prasannan, B.; Luh, P.B.; Zhang, L.

1996-01-01

Selling and purchasing power are important activities for utilities because of potential savings. When a selling utility presents an offer including prices, power levels and durations, a purchasing utility selects power levels and durations within the offered range subject to relevant constraints. The decisionmaking process is complicated because transactions are coupled with system demand and reserve, therefore decisions have to be made in conjunction with the commitment and dispatching of units. Furthermore, transaction decisions have to be made in almost real time in view of the competitiveness of the power market caused by deregulation. In this paper, transactions are analyzed from a selling utility's viewpoint for a system consisting of thermal, hydro and pumped-storage units. To effectively solve the problem, linear sale revenues are approximated by nonlinear functions, and non-profitable options are identified and eliminated from consideration. The multipliers are then updated at the high level by using a modified subgradient method to obtain near optimal solutions quickly. Testing results show that the algorithm produces good sale offers efficiently

Power Transmission Scheduling for Generators in a Deregulated Environment Based on a Game-Theoretic Approach

Directory of Open Access Journals (Sweden)

Bingtuan Gao

2015-12-01

Full Text Available In a deregulated environment of the power market, in order to lower their energy price and guarantee the stability of the power network, appropriate transmission lines have to be considered for electricity generators to sell their energy to the end users. This paper proposes a game-theoretic power transmission scheduling for multiple generators to lower their wheeling cost. Based on the embedded cost method, a wheeling cost model consisting of congestion cost, cost of losses and cost of transmission capacity is presented. By assuming each generator behaves in a selfish and rational way, the competition among the multiple generators is formulated as a non-cooperative game, where the players are the generators and the strategies are their daily schedules of power transmission. We will prove that there exists at least one pure-strategy Nash equilibrium of the formulated power transmission game. Moreover, a distributed algorithm will be provided to realize the optimization in terms of minimizing the wheeling cost. Finally, simulations were performed and discussed to verify the feasibility and effectiveness of the proposed non-cooperative game approach for the generators in a deregulated environment.

77 FR 42332 - Large Power Transformers From Korea; Revised Schedule for the Subject Investigation

Science.gov (United States)

2012-07-18

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-1189 (Final)] Large Power Transformers From Korea; Revised Schedule for the Subject Investigation AGENCY: United States International Trade Commission. ACTION: Notice. DATES: Effective Date: July 12, 2012. FOR FURTHER INFORMATION CONTACT: Edward...

Low-Complexity Scheduling and Power Adaptation for Coordinated Cloud-Radio Access Networks

KAUST Repository

Douik, Ahmed

2017-07-17

In practical wireless systems, the successful implementation of resource allocation techniques strongly depends on the algorithmic complexity. Consider a cloud-radio access network (CRAN), where the central cloud is responsible for scheduling devices to the frames’ radio resources blocks (RRBs) of the single-antenna base-stations (BSs), adjusting the transmit power levels, and for synchronizing the transmit frames across the connected BSs. Previous studies show that the jointly coordinated scheduling and power control problem in the considered CRAN can be solved using an approach that scales exponentially with the number of BSs, devices, and RRBs, which makes the practical implementation infeasible for reasonably sized networks. This paper instead proposes a low-complexity solution to the problem, under the constraints that each device cannot be served by more than one BS but can be served by multiple RRBs within each BS frame, and under the practical assumption that the channel is constant during the duration of each frame. The paper utilizes graph-theoretical based techniques and shows that constructing a single power control graph is sufficient to obtain the optimal solution with a complexity that is independent of the number of RRBs. Simulation results reveal the optimality of the proposed solution for slow-varying channels, and show that the solution performs near-optimal for highly correlated channels.

Optimal coordinated scheduling of combined heat and power fuel cell, wind, and photovoltaic units in micro grids considering uncertainties

International Nuclear Information System (INIS)

Bornapour, Mosayeb; Hooshmand, Rahmat-Allah; Khodabakhshian, Amin; Parastegari, Moein

2016-01-01

In this paper, a stochastic model is proposed for coordinated scheduling of combined heat and power units in micro grid considering wind turbine and photovoltaic units. Uncertainties of electrical market price; the speed of wind and solar radiation are considered using a scenario-based method. In the method, scenarios are generated using roulette wheel mechanism based on probability distribution functions of input random variables. Using this method, the probabilistic specifics of the problem are distributed and the problem is converted to a deterministic one. The type of the objective function, coordinated scheduling of combined heat and power, wind turbine, and photovoltaic units change this problem to a mixed integer nonlinear one. Therefore to solve this problem modified particle swarm optimization algorithm is employed. The mentioned uncertainties lead to an increase in profit. Moreover, the optimal coordinated scheduling of renewable energy resources and thermal units in micro grids increase the total profit. In order to evaluate the performance of the proposed method, its performance is executed on modified 33 bus distributed system as a micro grid. - Highlights: • Stochastic model is proposed for coordinated scheduling of renewable energy sources. • The effect of combined heat and power is considered. • Maximizing profits of micro grid is considered as objective function. • Considering the uncertainties of problem lead to profit increasing. • Optimal scheduling of renewable energy sources and thermal units increases profit.

Minimization of Load Variance in Power Grids—Investigation on Optimal Vehicle-to-Grid Scheduling

Directory of Open Access Journals (Sweden)

Kang Miao Tan

2017-11-01

Full Text Available The introduction of electric vehicles into the transportation sector helps reduce global warming and carbon emissions. The interaction between electric vehicles and the power grid has spurred the emergence of a smart grid technology, denoted as vehicle-to grid-technology. Vehicle-to-grid technology manages the energy exchange between a large fleet of electric vehicles and the power grid to accomplish shared advantages for the vehicle owners and the power utility. This paper presents an optimal scheduling of vehicle-to-grid using the genetic algorithm to minimize the power grid load variance. This is achieved by allowing electric vehicles charging (grid-to-vehicle whenever the actual power grid loading is lower than the target loading, while conducting electric vehicle discharging (vehicle-to-grid whenever the actual power grid loading is higher than the target loading. The vehicle-to-grid optimization algorithm is implemented and tested in MATLAB software (R2013a, MathWorks, Natick, MA, USA. The performance of the optimization algorithm depends heavily on the setting of the target load, power grid load and capability of the grid-connected electric vehicles. Hence, the performance of the proposed algorithm under various target load and electric vehicles’ state of charge selections were analysed. The effectiveness of the vehicle-to-grid scheduling to implement the appropriate peak load shaving and load levelling services for the grid load variance minimization is verified under various simulation investigations. This research proposal also recommends an appropriate setting for the power utility in terms of the selection of the target load based on the electric vehicle historical data.

Argentine hydrothermal panorama

Energy Technology Data Exchange (ETDEWEB)

1976-12-01

An attempt is made to give a realistic review of Argentine thermal waters. The topics discussed are the characteristics of the hydrothermal resources, classification according to their mineral content, hydrothermal flora and fauna, uses of hydrothermal resources, hydrothermal regions of Argentina, and meteorology and climate. A tabulation is presented of the principal thermal waters. (JSR)

Neuro-Fuzzy Computational Technique to Control Load Frequency in Hydro-Thermal Interconnected Power System

Science.gov (United States)

Prakash, S.; Sinha, S. K.

2015-09-01

In this research work, two areas hydro-thermal power system connected through tie-lines is considered. The perturbation of frequencies at the areas and resulting tie line power flows arise due to unpredictable load variations that cause mismatch between the generated and demanded powers. Due to rising and falling power demand, the real and reactive power balance is harmed; hence frequency and voltage get deviated from nominal value. This necessitates designing of an accurate and fast controller to maintain the system parameters at nominal value. The main purpose of system generation control is to balance the system generation against the load and losses so that the desired frequency and power interchange between neighboring systems are maintained. The intelligent controllers like fuzzy logic, artificial neural network (ANN) and hybrid fuzzy neural network approaches are used for automatic generation control for the two area interconnected power systems. Area 1 consists of thermal reheat power plant whereas area 2 consists of hydro power plant with electric governor. Performance evaluation is carried out by using intelligent (ANFIS, ANN and fuzzy) control and conventional PI and PID control approaches. To enhance the performance of controller sliding surface i.e. variable structure control is included. The model of interconnected power system has been developed with all five types of said controllers and simulated using MATLAB/SIMULINK package. The performance of the intelligent controllers has been compared with the conventional PI and PID controllers for the interconnected power system. A comparison of ANFIS, ANN, Fuzzy and PI, PID based approaches shows the superiority of proposed ANFIS over ANN, fuzzy and PI, PID. Thus the hybrid fuzzy neural network controller has better dynamic response i.e., quick in operation, reduced error magnitude and minimized frequency transients.

Techno-economic Assessment of Integrated Hydrothermal Liquefaction and Combined Heat and Power Production from Lignocellulose Residues

Directory of Open Access Journals (Sweden)

Mohamed Magdeldin

2018-03-01

Full Text Available Waste biomass as a mean for global carbon dioxide emissions mitigation remains under-utilized. This is mainly due to the low calorific value of virgin feedstock, characterized generally with high moisture content. Aqueous processing, namely hydrothermal liquefaction in subcritical water conditions, has been demonstrated experimentally to thermally densify solid lignocellulose into liquid fuels without the pre-requisite and energy consuming drying step. This study presents a techno-economic evaluation of an integrated hydrothermal liquefaction system with downstream combined heat and power production from forest residues. The utilization of the liquefaction by-products and waste heat from the elevated processing conditions, coupled with the chemical upgrading of the feedstock enables the poly-generation of biocrude, electricity and district heat. The plant thermal efficiency increases by 3.5 to 4.6% compared to the conventional direct combustion case. The economic assessment showed that the minimum selling price of biocrude, based on present co-products market prices, hinders commercialization and ranges between 138 EUR to 178 EUR per MWh. A sensitivity analysis and detailed discussion on the techno-economic assessment results are presented for the different process integration and market case scenarios.

Risk-constrained self-scheduling of a fuel and emission constrained power producer using rolling window procedure

International Nuclear Information System (INIS)

Kazempour, S. Jalal; Moghaddam, Mohsen Parsa

2011-01-01

This work addresses a relevant methodology for self-scheduling of a price-taker fuel and emission constrained power producer in day-ahead correlated energy, spinning reserve and fuel markets to achieve a trade-off between the expected profit and the risk versus different risk levels based on Markowitz's seminal work in the area of portfolio selection. Here, a set of uncertainties including price forecasting errors and available fuel uncertainty are considered. The latter uncertainty arises because of uncertainties in being called for reserve deployment in the spinning reserve market and availability of power plant. To tackle the price forecasting errors, variances of energy, spinning reserve and fuel prices along with their covariances which are due to markets correlation are taken into account using relevant historical data. In order to tackle available fuel uncertainty, a framework for self-scheduling referred to as rolling window is proposed. This risk-constrained self-scheduling framework is therefore formulated and solved as a mixed-integer non-linear programming problem. Furthermore, numerical results for a case study are discussed. (author)

Distributed decision-making in electric power system transmission maintenance scheduling using multi-agent systems (MAS)

Science.gov (United States)

Zhang, Zhong

In this work, motivated by the need to coordinate transmission maintenance scheduling among a multiplicity of self-interested entities in restructured power industry, a distributed decision support framework based on multiagent negotiation systems (MANS) is developed. An innovative risk-based transmission maintenance optimization procedure is introduced. Several models for linking condition monitoring information to the equipment's instantaneous failure probability are presented, which enable quantitative evaluation of the effectiveness of maintenance activities in terms of system cumulative risk reduction. Methodologies of statistical processing, equipment deterioration evaluation and time-dependent failure probability calculation are also described. A novel framework capable of facilitating distributed decision-making through multiagent negotiation is developed. A multiagent negotiation model is developed and illustrated that accounts for uncertainty and enables social rationality. Some issues of multiagent negotiation convergence and scalability are discussed. The relationships between agent-based negotiation and auction systems are also identified. A four-step MAS design methodology for constructing multiagent systems for power system applications is presented. A generic multiagent negotiation system, capable of inter-agent communication and distributed decision support through inter-agent negotiations, is implemented. A multiagent system framework for facilitating the automated integration of condition monitoring information and maintenance scheduling for power transformers is developed. Simulations of multiagent negotiation-based maintenance scheduling among several independent utilities are provided. It is shown to be a viable alternative solution paradigm to the traditional centralized optimization approach in today's deregulated environment. This multiagent system framework not only facilitates the decision-making among competing power system entities, but

Analysis of critical paths for schedule control of nuclear power projects

International Nuclear Information System (INIS)

Shi Liangmin; Ma Limin; Fan Kai

2005-01-01

Study on the critical paths for the schedule control of nuclear power projects has been performed for reactor M310, based on the experiences from Daya Bay project and Ling Ao project. The study shows that the critical paths for the nuclear power project are from NI civil work, NI erection, commissioning of single systems directly serving the CFT to the joint-test. For NI civil work, the critical path is the main civil work of the reactor building, pre-stressing, handover of rooms for important areas, and key CW-erection interfaces; there are four critical paths for NI erection; For startup, two stages can be identified: commissioning of 16 single systems directly serving the CFT and joint-test. (authors)

Scheduling Model for Renewable Energy Sources Integration in an Insular Power System

Directory of Open Access Journals (Sweden)

Gerardo J. Osório

2018-01-01

Full Text Available Insular power systems represent an asset and an excellent starting point for the development and analysis of innovative tools and technologies. The integration of renewable energy resources that has taken place in several islands in the south of Europe, particularly in Portugal, has brought more uncertainty to production management. In this work, an innovative scheduling model is proposed, which considers the integration of wind and solar resources in an insular power system in Portugal, with a strong conventional generation basis. This study aims to show the benefits of increasing the integration of renewable energy resources in this insular power system, and the objectives are related to minimizing the time for which conventional generation is in operation, maximizing profits, reducing production costs, and consequently, reducing greenhouse gas emissions.

Application of Hydrothermal Treatment to High Concentrated Sewage Sludge for Anaerobic Digestion Process

OpenAIRE

M. Orikawa; H. Kamahara; Y. Atsuta; H. Daimon

2013-01-01

Tomato and seaweed were produced by utilizing CO2 and heat discharged from power generation using biogas in Toyogawa biomass park, Japan. The biogas was obtained by anaerobic digestion with hydrothermal treatment. The hydrothermal treatment was applied to the high concentrated sewage sludge (22 % total solids (TS) dewatered sludge). The purpose of this study is to clarify the effect of hydrothermal treatment on the qualities of high concentrated sewage sludge, by analyzing particulate organic...

Integrated Cost and Schedule Control Systems for Nuclear Power Plant Construction: Leveraging Strategic Advantages to Owners and EPC Firms

Directory of Open Access Journals (Sweden)

Youngsoo Jung

2015-01-01

Full Text Available As the owners expect that the cost and time for nuclear power plant construction would decrease with new entrants into the market, there will be severer competition in the nuclear industry. In order to achieve performance improvement and to attain competitive advantages under the globalized competition, practitioners and researchers in the nuclear industry have recently exerted efforts to develop an advanced and efficient management methodology for the nuclear mega-projects. Among several candidates, integrated cost and schedule control system is of great concern because it can effectively manage the three most important project performances including cost, time, and quality. In this context, the purpose of this paper is to develop a project numbering system (PNS of integrated cost and schedule control system for nuclear power plant construction. Distinct attributes of nuclear power plant construction were investigated first in order to identify influencing variables that characterize real-world implementation of advanced cost and schedule controls. A scenario was then developed and analysed to simulate a case-project. By using this case-project, proposed management requirements, management methods, measurement techniques, data structure, and data collection methods for integrated cost and schedule PNS were illustrated. Finally, findings and implications are outlined, and recommendations for further research are presented.

An unit commitment model for hydrothermal systems; Um modelo de unit commitment para sistemas hidrotermicos

Energy Technology Data Exchange (ETDEWEB)

Franca, Thiago de Paula; Luciano, Edson Jose Rezende; Nepomuceno, Leonardo [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Dept. de Engenharia Eletrica], Emails: ra611191@feb.unesp.br, edson.joserl@uol.com.br, leo@feb.unesp.br

2009-07-01

A model of Unit Commitment to hydrothermal systems that includes the costs of start/stop of generators is proposed. These costs has been neglected in a good part of the programming models for operation of hydrothermal systems (pre-dispatch). The impact of the representation of costs in total production costs is evaluated. The proposed model is solved by a hybrid methodology, which involves the use of genetic algorithms (to solve the entire part of the problem) and sequential quadratic programming methods. This methodology is applied to the solution of an IEEE test system. The results emphasize the importance of representation of the start/stop in the generation schedule.

Optimal stochastic reactive power scheduling in a microgrid considering voltage droop scheme of DGs and uncertainty of wind farms

International Nuclear Information System (INIS)

Khorramdel, Benyamin; Raoofat, Mahdi

2012-01-01

Distributed Generators (DGs) in a microgrid may operate in three different reactive power control strategies, including PV, PQ and voltage droop schemes. This paper proposes a new stochastic programming approach for reactive power scheduling of a microgrid, considering the uncertainty of wind farms. The proposed algorithm firstly finds the expected optimal operating point of each DG in V-Q plane while the wind speed is a probabilistic variable. A multi-objective function with goals of loss minimization, reactive power reserve maximization and voltage security margin maximization is optimized using a four-stage multi-objective nonlinear programming. Then, using Monte Carlo simulation enhanced by scenario reduction technique, the proposed algorithm simulates actual condition and finds optimal operating strategy of DGs. Also, if any DGs are scheduled to operate in voltage droop scheme, the optimum droop is determined. Also, in the second part of the research, to enhance the optimality of the results, PSO algorithm is used for the multi-objective optimization problem. Numerical examples on IEEE 34-bus test system including two wind turbines are studied. The results show the benefits of voltage droop scheme for mitigating the impacts of the uncertainty of wind. Also, the results show preference of PSO method in the proposed approach. -- Highlights: ► Reactive power scheduling in a microgrid considering loss and voltage security. ► Stochastic nature of wind farms affects reactive power scheduling and is considered. ► Advantages of using the voltage droop characteristics of DGs in voltage security are shown. ► Power loss, voltage security and VAR reserve are three goals of a multi-objective optimization. ► Monte Carlo method with scenario reduction is used to determine optimal control strategy of DGs.

Development of the Optimum Operation Scheduling Model of Domestic Electric Appliances for the Supply-Demand Adjustment in a Power System

Science.gov (United States)

Ikegami, Takashi; Iwafune, Yumiko; Ogimoto, Kazuhiko

The high penetration of variable renewable generation such as Photovoltaic (PV) systems will cause the issue of supply-demand imbalance in a whole power system. The activation of the residential power usage, storage and generation by sophisticated scheduling and control using the Home Energy Management System (HEMS) will be needed to balance power supply and demand in the near future. In order to evaluate the applicability of the HEMS as a distributed controller for local and system-wide supply-demand balances, we developed an optimum operation scheduling model of domestic electric appliances using the mixed integer linear programming. Applying this model to several houses with dynamic electricity prices reflecting the power balance of the total power system, it was found that the adequate changes in electricity prices bring about the shift of residential power usages to control the amount of the reverse power flow due to excess PV generation.

Multi-objective stochastic scheduling optimization model for connecting a virtual power plant to wind-photovoltaic-electric vehicles considering uncertainties and demand response

International Nuclear Information System (INIS)

Ju, Liwei; Li, Huanhuan; Zhao, Junwei; Chen, Kangting; Tan, Qingkun; Tan, Zhongfu

2016-01-01

Highlights: • Our research focuses on virtual power plant. • Electric vehicle group and demand response are integrated into virtual power plant. • Stochastic chance constraint planning is applied to overcome uncertainties. • A multi-objective stochastic scheduling model is proposed for virtual power plant. • A three-stage hybrid intelligent solution algorithm is proposed for solving the model. - Abstract: A stochastic chance-constrained planning method is applied to build a multi-objective optimization model for virtual power plant scheduling. Firstly, the implementation cost of demand response is calculated using the system income difference. Secondly, a wind power plant, photovoltaic power, an electric vehicle group and a conventional power plant are aggregated into a virtual power plant. A stochastic scheduling model is proposed for the virtual power plant, considering uncertainties under three objective functions. Thirdly, a three-stage hybrid intelligent solution algorithm is proposed, featuring the particle swarm optimization algorithm, the entropy weight method and the fuzzy satisfaction theory. Finally, the Yunnan distributed power demonstration project in China is utilized for example analysis. Simulation results demonstrate that when considering uncertainties, the system will reduce the grid connection of the wind power plant and photovoltaic power to decrease the power shortage punishment cost. The average reduction of the system power shortage punishment cost and the operation revenue of virtual power plant are 61.5% and 1.76%, respectively, while the average increase of the system abandoned energy cost is 40.4%. The output of the virtual power plant exhibits a reverse distribution with the confidence degree of the uncertainty variable. The proposed algorithm rapidly calculates a global optimal set. The electric vehicle group could provide spinning reserve to ensure stability of the output of the virtual power plant. Demand response could

Influence of hydrothermal processing on functional properties and grain morphology of finger millet.

Science.gov (United States)

Dharmaraj, Usha; Meera, M S; Reddy, S Yella; Malleshi, Nagappa G

2015-03-01

Finger millet was hydrothermally processed followed by decortication. Changes in color, diameter, density, sphericity, thermal and textural characteristics and also some of the functional properties of the millet along with the grain morphology of the kernels after hydrothermal processing and decortication were studied. It was observed that, the millet turned dark after hydrothermal processing and color improved over native millet after decortication. A slight decrease in grain diameter was observed but sphericity of the grains increased on decortication. The soft and fragile endosperm turned into a hard texture and grain hardness increased by about 6 fold. Hydrothermal processing increased solubility and swelling power of the millet at ambient temperature. Pasting profile indicated that, peak viscosity decreased significantly on hydrothermal processing and both hydrothermally processed and decorticated millet exhibited zero breakdown viscosity. Enthalpy was negative for hydrothermally processed millet and positive for decorticated grains. Microscopic studies revealed that the orderly structure of endosperm changed to a coherent mass after hydrothermal processing and the different layers of seed coat get fused with the endosperm.

Effects of a shortened depreciation schedule on the investment costs for combined heat and power; TOPICAL

International Nuclear Information System (INIS)

Kranz, Nicole; Worrell, Ernst

2001-01-01

We investigate and compare several generic depreciation methods to assess the effectiveness of possible policy measures with respect to the depreciation schedules for investments in combined heat and power plants in the United States. We assess the different depreciation methods for CHP projects of various sizes (ranging from 1 MW to 100 MW). We evaluate the impact of different depreciation schedules on the tax shield, and the resulting tax savings to potential investors. We show that a shorter depreciation cycle could have a substantial impact on the cost of producing power, making cogeneration more attractive. The savings amount to approximately 6-7 percent of capital and fixed operation and maintenance costs, when changing from the current system to a 7 year depreciation scheme with switchover from declining balance to straight line depreciation. Suggestions for further research to improve the analysis are given

Deterministic and stochastic approach for safety and reliability optimization of captive power plant maintenance scheduling using GA/SA-based hybrid techniques: A comparison of results

International Nuclear Information System (INIS)

Mohanta, Dusmanta Kumar; Sadhu, Pradip Kumar; Chakrabarti, R.

2007-01-01

This paper presents a comparison of results for optimization of captive power plant maintenance scheduling using genetic algorithm (GA) as well as hybrid GA/simulated annealing (SA) techniques. As utilities catered by captive power plants are very sensitive to power failure, therefore both deterministic and stochastic reliability objective functions have been considered to incorporate statutory safety regulations for maintenance of boilers, turbines and generators. The significant contribution of this paper is to incorporate stochastic feature of generating units and that of load using levelized risk method. Another significant contribution of this paper is to evaluate confidence interval for loss of load probability (LOLP) because some variations from optimum schedule are anticipated while executing maintenance schedules due to different real-life unforeseen exigencies. Such exigencies are incorporated in terms of near-optimum schedules obtained from hybrid GA/SA technique during the final stages of convergence. Case studies corroborate that same optimum schedules are obtained using GA and hybrid GA/SA for respective deterministic and stochastic formulations. The comparison of results in terms of interval of confidence for LOLP indicates that levelized risk method adequately incorporates the stochastic nature of power system as compared with levelized reserve method. Also the interval of confidence for LOLP denotes the possible risk in a quantified manner and it is of immense use from perspective of captive power plants intended for quality power

Decommissioning strategy and schedule for a multiple reactor nuclear power plant site

Energy Technology Data Exchange (ETDEWEB)

Monteiro, Deiglys Borges; Moreira, Joao M.L.; Maiorino, Jose Rubens, E-mail: deiglys.monteiro@ufabc.edu.br, E-mail: joao.moreira@ufabc.edu.br, E-mail: joserubens.maiorino@ufabc.edu.br [Universidade Federal do ABC (CECS/UFABC), Santo Andre, SP (Brazil). Centro de Engenharia, Modelagem e Ciencias Aplicadas

2015-07-01

The decommissioning is an important part of every Nuclear Power Plant life cycle gaining importance when there are more than one plant at the same site due to interactions that can arise from the operational ones and a decommissioning plant. In order to prevent undesirable problems, a suitable strategy and a very rigorous schedule should implemented and carried. In this way, decommissioning tasks such as fully decontamination and dismantling of activated and contaminated systems, rooms and structures could be delayed, posing as an interesting option to multiple reactor sites. The present work aims to purpose a strategy and a schedule for the decommissioning of a multiple reactor site highlighting the benefits of delay operational tasks and constructs some auxiliary services in the site during the stand by period of the shutdown plants. As a case study, will be presented a three-reactor site which the decommissioning process actually is in planning stage and that should start in the next decade. (author)

Decommissioning strategy and schedule for a multiple reactor nuclear power plant site

International Nuclear Information System (INIS)

Monteiro, Deiglys Borges; Moreira, Joao M.L.; Maiorino, Jose Rubens

2015-01-01

The decommissioning is an important part of every Nuclear Power Plant life cycle gaining importance when there are more than one plant at the same site due to interactions that can arise from the operational ones and a decommissioning plant. In order to prevent undesirable problems, a suitable strategy and a very rigorous schedule should implemented and carried. In this way, decommissioning tasks such as fully decontamination and dismantling of activated and contaminated systems, rooms and structures could be delayed, posing as an interesting option to multiple reactor sites. The present work aims to purpose a strategy and a schedule for the decommissioning of a multiple reactor site highlighting the benefits of delay operational tasks and constructs some auxiliary services in the site during the stand by period of the shutdown plants. As a case study, will be presented a three-reactor site which the decommissioning process actually is in planning stage and that should start in the next decade. (author)

Strategic Maintenance Scheduling of an Offshore Wind Farm in a Deregulated Power System

Directory of Open Access Journals (Sweden)

Peyman Mazidi

2017-03-01

Full Text Available This paper proposes a model for strategic maintenance scheduling of offshore wind farms (SMSOWF in a deregulated power system. The objective of the model is to plan the maintenance schedules in a way to maximize the profit of the offshore wind farm. In addition, some network constraints, such as transmission lines capacity, and wind farm constraints, such as labor working shift, wave height limit and wake effect, as well as unexpected outages, are included in deterministic and stochastic studies. Moreover, the proposedmodel provides theability to incorporate information from condition monitoring systems. SMSOWF is formulated through a bi-level formulation and then transformed into a single-level through Karush–Kuhn–Tucker conditions. The model is validated through a test system, and the results demonstrate applicability, advantages and challenges of harnessing the full potential of the model.

Combined Rate and Power Allocation with Link Scheduling in Wireless Data Packet Relay Networks with Fading Channels

OpenAIRE

Subhrakanti Dey; Minyi Huang

2007-01-01

We consider a joint rate and power control problem in a wireless data traffic relay network with fading channels. The optimization problem is formulated in terms of power and rate selection, and link transmission scheduling. The objective is to seek high aggregate utility of the relay node when taking into account buffer load management and power constraints. The optimal solution for a single transmitting source is computed by a two-layer dynamic programming algorithm which leads to optimal ...

Optimization of Temperature Schedule Parameters on Heat Supply in Power-and-Heat Supply Systems

Directory of Open Access Journals (Sweden)

V. A. Sednin

2009-01-01

Full Text Available The paper considers problems concerning optimization of a temperature schedule in the district heating systems with steam-turbine thermal power stations having average initial steam parameters. It has been shown in the paper that upkeeping of an optimum network water temperature permits to increase an energy efficiency of heat supply due to additional systematic saving of fuel. 

Staffing, overtime, and shift scheduling project

International Nuclear Information System (INIS)

Lewis, P.M.

1989-01-01

Recent events at the Peach Bottom nuclear power plant have demonstrated the need to establish a quantifiable basis for assessing the safety significance of long work hours on nuclear power plant operators. The incidents at TMI-2, Chernobyl, and Bhopal, which all occurred during the late evening/night shift, further highlight the importance of the relationship between shift scheduling and performance. The objective of this project is to estimate, using statistical analysis on data from the nuclear industry, the effects on safety of staffing levels, overtime, and shift scheduling for operators and maintenance personnel. Regarding staffing levels, the Nuclear Regulatory Commission (NRC) currently has no explicit regulation concerning the minimum acceptable levels of staffing in a plant that has an operating license. The NRC has no systematic method for collecting data on the number of licensed operators on the operating crews. In 1982 the NRC recommended that plants write into their technical specifications a model policy on overtime. Currently, 77 nuclear power plant units have the model policy or a modification of it written into their technical specifications; 33 units have no policy on overtime. The model policy sets limits on overtime for safety related personnel, although these limits can be exceeded with plant manger approval. The US nuclear power industry has three types of shift schedules: (1) forward-rotating 8-hour/day shift schedules, (2) backward-rotating 8-hour/day schedules, and (3) 12-hour/day schedules

Recommendations for NRC policy on shift scheduling and overtime at nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Lewis, P.M.

1985-07-01

This report contains the Pacific Northwest Laboratory's (PNL's) recommendations to the US Nuclear Regulatory Commission (NRC) for an NRC policy on shift scheduling and hours of work (including overtime) for control room operators and other safety-related personnel in nuclear power plants. First, it is recommended that NRC make three additions to its present policy on overtime: (1) limit personnel to 112 hours of work in a 14-day period, 192 hours in 28 days, and 2260 hours in one year; exceeding these limits would require plant manager approval; (2) add a requirement that licensees obtain approval from NRC if plant personnel are expected to exceed 72 hours of work in a 7-day period, 132 hours in 14 days, 228 hours in 28 days, and 2300 hours in one year; and (3) make the policy a requirement, rather than a nonbinding recommendation. Second, it is recommended that licensees be required to obtain NRC approval to adopt a routine 12-hour/day shift schedule. Third, it is recommended that NRC add several nonbinding recommendations concerning routine 8-hour/day schedules. Finally, because additional data can strengthen the basis for future NRC policy on overtime, five methods are suggested for collecting data on overtime and its effects. 44 refs., 10 tabs.

Recommendations for NRC policy on shift scheduling and overtime at nuclear power plants

International Nuclear Information System (INIS)

Lewis, P.M.

1985-07-01

This report contains the Pacific Northwest Laboratory's (PNL's) recommendations to the US Nuclear Regulatory Commission (NRC) for an NRC policy on shift scheduling and hours of work (including overtime) for control room operators and other safety-related personnel in nuclear power plants. First, it is recommended that NRC make three additions to its present policy on overtime: (1) limit personnel to 112 hours of work in a 14-day period, 192 hours in 28 days, and 2260 hours in one year; exceeding these limits would require plant manager approval; (2) add a requirement that licensees obtain approval from NRC if plant personnel are expected to exceed 72 hours of work in a 7-day period, 132 hours in 14 days, 228 hours in 28 days, and 2300 hours in one year; and (3) make the policy a requirement, rather than a nonbinding recommendation. Second, it is recommended that licensees be required to obtain NRC approval to adopt a routine 12-hour/day shift schedule. Third, it is recommended that NRC add several nonbinding recommendations concerning routine 8-hour/day schedules. Finally, because additional data can strengthen the basis for future NRC policy on overtime, five methods are suggested for collecting data on overtime and its effects. 44 refs., 10 tabs

The power of reordering for online minimum makespan scheduling

OpenAIRE

Englert, Matthias; Özmen, Deniz; Westermann, Matthias

2014-01-01

In the classic minimum makespan scheduling problem, we are given an input sequence of jobs with processing times. A scheduling algorithm has to assign the jobs to m parallel machines. The objective is to minimize the makespan, which is the time it takes until all jobs are processed. In this paper, we consider online scheduling algorithms without preemption. However, we do not require that each arriving job has to be assigned immediately to one of the machines. A reordering buffer with limited...

Load frequency control of three area interconnected hydro-thermal ...

African Journals Online (AJOL)

user

hydrothermal reheat power system by the use of Artificial Intelligent and PI Controller. ... form of Kinetic Energy stored in generator prime mover set, which results the ... A control strategy is needed that not only maintains constancy of frequency ...

Realistic Scheduling Mechanism for Smart Homes

Directory of Open Access Journals (Sweden)

Danish Mahmood

2016-03-01

Full Text Available In this work, we propose a Realistic Scheduling Mechanism (RSM to reduce user frustration and enhance appliance utility by classifying appliances with respective constraints and their time of use effectively. Algorithms are proposed regarding functioning of home appliances. A 24 hour time slot is divided into four logical sub-time slots, each composed of 360 min or 6 h. In these sub-time slots, only desired appliances (with respect to appliance classification are scheduled to raise appliance utility, restricting power consumption by a dynamically modelled power usage limiter that does not only take the electricity consumer into account but also the electricity supplier. Once appliance, time and power usage limiter modelling is done, we use a nature-inspired heuristic algorithm, Binary Particle Swarm Optimization (BPSO, optimally to form schedules with given constraints representing each sub-time slot. These schedules tend to achieve an equilibrium amongst appliance utility and cost effectiveness. For validation of the proposed RSM, we provide a comparative analysis amongst unscheduled electrical load usage, scheduled directly by BPSO and RSM, reflecting user comfort, which is based upon cost effectiveness and appliance utility.

The applicability of knowledge-based scheduling to the utilities industry

International Nuclear Information System (INIS)

Yoshimoto, G.; Gargan, R. Jr.; Duggan, P.

1992-01-01

The Electric Power Research Institute (EPRI), Nuclear Power Division, has identified the three major goals of high technology applications for nuclear power plants. These goals are to enhance power production through increasing power generation efficiency, to increase productivity of the operations, and to reduce the threats to the safety of the plant. Our project responds to the second goal by demonstrating that significant productivity increases can be achieved for outage maintenance operations based on existing knowledge-based scheduling technology. Its use can also mitigate threats to potential safety problems by means of the integration of risk assessment features into the scheduler. The scheduling approach uses advanced techniques enabling the automation of the routine scheduling decision process that previously was handled by people. The process of removing conflicts in scheduling is automated. This is achieved by providing activity representations that allow schedulers to express a variety of different scheduling constraints and by implementing scheduling mechanisms that simulate kinds of processes that humans use to find better solutions from a large number of possible solutions. This approach allows schedulers to express detailed constraints between activities and other activities, resources (material and personnel), and requirements that certain states exist for their execution. Our scheduler has already demonstrated its benefit to improving the shuttle processing flow management at Kennedy Space Center. Knowledge-based scheduling techniques should be examined by utilities industry researchers, developers, operators and management for application to utilities planning problems because of its great cost benefit potential. 4 refs., 4 figs

Flower-like CuO synthesized by CTAB-assisted hydrothermal method

Indian Academy of Sciences (India)

Administrator

and crystalline structure, the control of the shape and size of the semiconductors ... hydrothermal process using copper threads as precursor and pointed out ... 2.3 Instrumentation. Power X-ray .... Measurement of Tianjin University. References.

A bi-level stochastic scheduling optimization model for a virtual power plant connected to a wind–photovoltaic–energy storage system considering the uncertainty and demand response

International Nuclear Information System (INIS)

Ju, Liwei; Tan, Zhongfu; Yuan, Jinyun; Tan, Qingkun; Li, Huanhuan; Dong, Fugui

2016-01-01

Highlights: • Our research focuses on Virtual Power Plant (VPP). • Virtual Power Plant consists of WPP, PV, CGT, ESSs and DRPs. • Robust optimization theory is introduced to analyze uncertainties. • A bi-level stochastic scheduling optimization model is proposed for VPP. • Models are built to measure the impacts of ESSs and DERPs on VPP operation. - Abstract: To reduce the uncertain influence of wind power and solar photovoltaic power on virtual power plant (VPP) operation, robust optimization theory (ROT) is introduced to build a stochastic scheduling model for VPP considering the uncertainty, price-based demand response (PBDR) and incentive-based demand response (IBDR). First, the VPP components are described including the wind power plant (WPP), photovoltaic generators (PV), convention gas turbine (CGT), energy storage systems (ESSs) and demand resource providers (DRPs). Then, a scenario generation and reduction frame is proposed for analyzing and simulating output stochastics based on the interval method and the Kantorovich distance. Second, a bi-level robust scheduling model is proposed with a double robust coefficient for WPP and PV. In the upper layer model, the maximum VPP operation income is taken as the optimization objective for building the scheduling model with the day-ahead prediction output of WPP and PV. In the lower layer model, the day-ahead scheduling scheme is revised with the actual output of the WPP and PV under the objectives of the minimum system net load and the minimum system operation cost. Finally, the independent micro-grid in a coastal island in eastern China is used for the simulation analysis. The results illustrate that the model can overcome the influence of uncertainty on VPP operations and reduce the system power shortage cost by connecting the day-ahead scheduling with the real-time scheduling. ROT could provide a flexible decision tool for decision makers, effectively addressing system uncertainties. ESSs could

Optimal stochastic coordinated scheduling of proton exchange membrane fuel cell-combined heat and power, wind and photovoltaic units in micro grids considering hydrogen storage

International Nuclear Information System (INIS)

Bornapour, Mosayeb; Hooshmand, Rahmat-Allah; Khodabakhshian, Amin; Parastegari, Moein

2017-01-01

Highlights: •Stochastic model is proposed for coordinated scheduling of renewable energy sources. •The effect of combined heat and power is considered. •Hydrogen storage is considered for fuel cells. •Maximizing profits of micro grid is considered as objective function. •Considering the uncertainties of problem lead to profit increasing. -- Abstract: Nowadays, renewable energy sources and combined heat and power units are extremely used in micro grids, so it is necessary to schedule these units to improve the performance of the system. In this regard, a stochastic model is proposed in this paper to schedule proton exchange membrane fuel cell-combined heat and power, wind turbines, and photovoltaic units coordinately in a micro grid while considering hydrogen storage. Hydrogen storage strategy is considered for the operation of proton exchange membrane fuel cell-combined heat and power units. To consider stochastic generation of renewable energy source units in this paper, a scenario-based method is used. In this method, the uncertainties of electrical market price, the wind speed, and solar irradiance are considered. This stochastic scheduling problem is a mixed integer- nonlinear programming which considers the proposed objective function and variables of coordinated scheduling of PEMFC-CHP, wind turbines and photovoltaic units. It also considers hydrogen storage strategy and converts it to a mixed integer nonlinear problem. In this study a modified firefly algorithm is used to solve the problem. This method is examined on modified 33-bus distributed network as a MG for its performance.

Artificial intelligence approaches to astronomical observation scheduling

Science.gov (United States)

Johnston, Mark D.; Miller, Glenn

1988-01-01

Automated scheduling will play an increasing role in future ground- and space-based observatory operations. Due to the complexity of the problem, artificial intelligence technology currently offers the greatest potential for the development of scheduling tools with sufficient power and flexibility to handle realistic scheduling situations. Summarized here are the main features of the observatory scheduling problem, how artificial intelligence (AI) techniques can be applied, and recent progress in AI scheduling for Hubble Space Telescope.

Load frequency control of three area interconnected hydro-thermal ...

African Journals Online (AJOL)

This paper present analysis on dynamic performance of Load Frequency Control (LFC) of three area interconnected hydrothermal reheat power system by the use of Artificial Intelligent and PI Controller. In the proposed scheme, control methodology developed using conventional PI controller, Artificial Neural Network ...

A Practical Framework to Study Low-Power Scheduling Algorithms on Real-Time and Embedded Systems

Directory of Open Access Journals (Sweden)

Jian (Denny Lin

2014-05-01

Full Text Available With the advanced technology used to design VLSI (Very Large Scale Integration circuits, low-power and energy-efficiency have played important roles for hardware and software implementation. Real-time scheduling is one of the fields that has attracted extensive attention to design low-power, embedded/real-time systems. The dynamic voltage scaling (DVS and CPU shut-down are the two most popular techniques used to design the algorithms. In this paper, we firstly review the fundamental advances in the research of energy-efficient, real-time scheduling. Then, a unified framework with a real Intel PXA255 Xscale processor, namely real-energy, is designed, which can be used to measure the real performance of the algorithms. We conduct a case study to evaluate several classical algorithms by using the framework. The energy efficiency and the quantitative difference in their performance, as well as the practical issues found in the implementation of these algorithms are discussed. Our experiments show a gap between the theoretical and real results. Our framework not only gives researchers a tool to evaluate their system designs, but also helps them to bridge this gap in their future works.

Hydrothermal Processes

Science.gov (United States)

German, C. R.; von Damm, K. L.

2003-12-01

What is Hydrothermal Circulation?Hydrothermal circulation occurs when seawater percolates downward through fractured ocean crust along the volcanic mid-ocean ridge (MOR) system. The seawater is first heated and then undergoes chemical modification through reaction with the host rock as it continues downward, reaching maximum temperatures that can exceed 400 °C. At these temperatures the fluids become extremely buoyant and rise rapidly back to the seafloor where they are expelled into the overlying water column. Seafloor hydrothermal circulation plays a significant role in the cycling of energy and mass between the solid earth and the oceans; the first identification of submarine hydrothermal venting and their accompanying chemosynthetically based communities in the late 1970s remains one of the most exciting discoveries in modern science. The existence of some form of hydrothermal circulation had been predicted almost as soon as the significance of ridges themselves was first recognized, with the emergence of plate tectonic theory. Magma wells up from the Earth's interior along "spreading centers" or "MORs" to produce fresh ocean crust at a rate of ˜20 km3 yr-1, forming new seafloor at a rate of ˜3.3 km2 yr-1 (Parsons, 1981; White et al., 1992). The young oceanic lithosphere formed in this way cools as it moves away from the ridge crest. Although much of this cooling occurs by upward conduction of heat through the lithosphere, early heat-flow studies quickly established that a significant proportion of the total heat flux must also occur via some additional convective process (Figure 1), i.e., through circulation of cold seawater within the upper ocean crust (Anderson and Silbeck, 1981). (2K)Figure 1. Oceanic heat flow versus age of ocean crust. Data from the Pacific, Atlantic, and Indian oceans, averaged over 2 Ma intervals (circles) depart from the theoretical cooling curve (solid line) indicating convective cooling of young ocean crust by circulating seawater

Comparison on electrically pumped random laser actions of hydrothermal and sputtered ZnO films

International Nuclear Information System (INIS)

Wang, Canxing; Jiang, Haotian; Li, Yunpeng; Ma, Xiangyang; Yang, Deren

2013-01-01

Random lasing (RL) in polycrystalline ZnO films is an intriguing research subject. Here, we have comparatively investigated electrically pumped RL behaviors of two metal-insulator-semiconductor structured devices using the hydrothermal and sputtered ZnO films as the semiconductor components, i.e., the light-emitting layers, respectively. It is demonstrated that the device using the hydrothermal ZnO film exhibits smaller threshold current and larger output optical power of the electrically pumped RL. The morphological characterization shows that the hydrothermal ZnO film is somewhat porous and is much rougher than the sputtered one, suggesting that in the former stronger multiple light scattering can occur. Moreover, the photoluminescence characterization indicates that there are fewer defects in the hydrothermal ZnO film than in the sputtered one, which means that the photons can pick up larger optical gain through stimulated emission in the hydrothermal ZnO film. Therefore, it is believed that the stronger multiple light scattering and larger optical gain contribute to the improved performance of the electrically pumped RL from the device using the hydrothermal ZnO film

18 CFR 420.41 - Schedule of water charges.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Schedule of water charges. 420.41 Section 420.41 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Charges; Exemptions § 420.41 Schedule of water...

Techno-economic analysis of solar integrated hydrothermal liquefaction of microalgae

International Nuclear Information System (INIS)

Pearce, Matthew; Shemfe, Mobolaji; Sansom, Christopher

2016-01-01

Highlights: • Hydrothermal liquefaction and concentrated solar power provide integrated biofuel technology. • Heat kinetics and energy efficiency Aspen plus modelling of CSP and HTL. • Microalgae biofuel minimum fuel sales price of $1.23/kg. - Abstract: Integration of Hydrothermal Liquefaction (HTL) of microalgae biomass with concentrated solar power thermal processing (CSP) for bio-oil production is a potential processing pathway for energy efficient generation of renewable biofuels. Solar HTL infrastructure avoids additional bolt-on components of conventional solar parabolic trough systems used for electricity production including heat transfer fluids, counter current heat exchangers, fluid transfer interconnectivity and electrical power control systems. The absence of such capital intensive additional equipment considerably reduces the production costs of solar HTL biofuels compared to electricity generation from conventional CSP power systems. An economic and market appraisal of variance and system economic resilience is presented. It is hypothesised that the combination of nutrient recycling with HTL/CSP unification has the potential for economically sustainable microalgae bio-oil production. A microalgae biofuel minimum fuel sales price of $1.23/kg has been modelled. Further experimental work would be able to validate this integrated model.

Delay consequencies in the construction time-schedule of nuclear power plants in relation to its safety and quality

International Nuclear Information System (INIS)

Recalde, J.A.

1991-01-01

An important delay in the construction time-schedule of a Nuclear Power Plant affects its safety and quality. This mainly occurs as a consequence of four reasons: discontinuity of the personnel working for the project; discontinuities of project suppliers; new safety and quality concepts; long-term storage. This work analyses each of the above reasons so as to foresee countermeasures to garantee the non deterioration of a Nuclear Power Plant. (author)

A SCHEDULING SCHEME WITH DYNAMIC FREQUENCY CLOCKING AND MULTIPLE VOLTAGES FOR LOW POWER DESIGNS

Institute of Scientific and Technical Information of China (English)

Wen Dongxin; Wang Ling; Yang Xiaozong

2007-01-01

In this letter, a scheduling scheme based on Dynamic Frequency Clocking (DFC) and multiple voltages is proposed for low power designs under the timing and the resource constraints.Unlike the conventional methods at high level synthesis where only voltages of nodes were considered,the scheme based on a gain function considers both voltage and frequency simultaneously to reduce energy consumption. Experiments with a number of DSP benchmarks show that the proposed scheme achieves an effective energy reduction.

Combined Rate and Power Allocation with Link Scheduling in Wireless Data Packet Relay Networks with Fading Channels

Directory of Open Access Journals (Sweden)

Subhrakanti Dey

2007-08-01

Full Text Available We consider a joint rate and power control problem in a wireless data traffic relay network with fading channels. The optimization problem is formulated in terms of power and rate selection, and link transmission scheduling. The objective is to seek high aggregate utility of the relay node when taking into account buffer load management and power constraints. The optimal solution for a single transmitting source is computed by a two-layer dynamic programming algorithm which leads to optimal power, rate, and transmission time allocation at the wireless links. We further consider an optimal power allocation problem for multiple transmitting sources in the same framework. Performances of the resource allocation algorithms including the effect of buffer load control are illustrated via extensive simulation studies.

Short term scheduling of multiple grid-parallel PEM fuel cells for microgrid applications

Energy Technology Data Exchange (ETDEWEB)

El-Sharkh, M.Y.; Rahman, A.; Alam, M.S. [Dept. of Electrical and Computer Engineering, University of South Alabama, Mobile, AL 36688 (United States)

2010-10-15

This paper presents a short term scheduling scheme for multiple grid-parallel PEM fuel cell power plants (FCPPs) connected to supply electrical and thermal energy to a microgrid community. As in the case of regular power plants, short term scheduling of FCPP is also a cost-based optimization problem that includes the cost of operation, thermal power recovery, and the power trade with the local utility grid. Due to the ability of the microgrid community to trade power with the local grid, the power balance constraint is not applicable, other constraints like the real power operating limits of the FCPP, and minimum up and down time are therefore used. To solve the short term scheduling problem of the FCPPs, a hybrid technique based on evolutionary programming (EP) and hill climbing technique (HC) is used. The EP is used to estimate the optimal schedule and the output power from each FCPP. The HC technique is used to monitor the feasibility of the solution during the search process. The short term scheduling problem is used to estimate the schedule and the electrical and thermal power output of five FCPPs supplying a maximum power of 300 kW. (author)

Complexing and hydrothermal ore deposition

CERN Document Server

Helgeson, Harold C

1964-01-01

Complexing and Hydrothermal Ore Deposition provides a synthesis of fact, theory, and interpretative speculation on hydrothermal ore-forming solutions. This book summarizes information and theory of the internal chemistry of aqueous electrolyte solutions accumulated in previous years. The scope of the discussion is limited to those aspects of particular interest to the geologist working on the problem of hydrothermal ore genesis. Wherever feasible, fundamental principles are reviewed. Portions of this text are devoted to calculations of specific hydrothermal equilibriums in multicompone

Prospects for energy recovery during hydrothermal and biological processing of waste biomass.

Science.gov (United States)

Gerber Van Doren, Léda; Posmanik, Roy; Bicalho, Felipe A; Tester, Jefferson W; Sills, Deborah L

2017-02-01

Thermochemical and biological processes represent promising technologies for converting wet biomasses, such as animal manure, organic waste, or algae, to energy. To convert biomass to energy and bio-chemicals in an economical manner, internal energy recovery should be maximized to reduce the use of external heat and power. In this study, two conversion pathways that couple hydrothermal liquefaction with anaerobic digestion or catalytic hydrothermal gasification were compared. Each of these platforms is followed by two alternative processes for gas utilization: 1) combined heat and power; and 2) combustion in a boiler. Pinch analysis was applied to integrate thermal streams among unit processes and improve the overall system efficiency. A techno-economic analysis was conducted to compare the feasibility of the four modeled scenarios under different market conditions. Our results show that a systems approach designed to recover internal heat and power can reduce external energy demands and increase the overall process sustainability. Copyright © 2016 Elsevier Ltd. All rights reserved.

PRACTICAL IMPLICATIONS OF LOCATION-BASED SCHEDULING

DEFF Research Database (Denmark)

Andersson, Niclas; Christensen, Knud

2007-01-01

The traditional method for planning, scheduling and controlling activities and resources in construction projects is the CPM-scheduling, which has been the predominant scheduling method since its introduction in the late 1950s. Over the years, CPM has proven to be a very powerful technique...... that will be used in this study. LBS is a scheduling method that rests upon the theories of line-of-balance and which uses the graphic representation of a flowline chart. As such, LBS is adapted for planning and management of workflows and, thus, may provide a solution to the identified shortcomings of CPM. Even...

Genome-resolved metagenomics reveals that sulfur metabolism dominates the microbial ecology of rising hydrothermal plumes

Science.gov (United States)

Anantharaman, K.; Breier, J. A., Jr.; Jain, S.; Reed, D. C.; Dick, G.

2015-12-01

Deep-sea hydrothermal plumes occur when hot fluids from hydrothermal vents replete with chemically reduced elements and compounds like sulfide, methane, hydrogen, ammonia, iron and manganese mix with cold, oxic seawater. Chemosynthetic microbes use these reduced chemicals to power primary production and are pervasive throughout the deep sea, even at sites far removed from hydrothermal vents. Although neutrally-buoyant hydrothermal plumes have been well-studied, rising hydrothermal plumes have received little attention even though they represent an important interface in the deep-sea where microbial metabolism and particle formation processes control the transformation of important elements and impact global biogeochemical cycles. In this study, we used genome-resolved metagenomic analyses and thermodynamic-bioenergetic modeling to study the microbial ecology of rising hydrothermal plumes at five different hydrothermal vents spanning a range of geochemical gradients at the Eastern Lau Spreading Center (ELSC) in the Western Pacific Ocean. Our analyses show that differences in the geochemistry of hydrothermal vents do not manifest in microbial diversity and community composition, both of which display only minor variance across ELSC hydrothermal plumes. Microbial metabolism is dominated by oxidation of reduced sulfur species and supports a diversity of bacteria, archaea and viruses that provide intriguing insights into metabolic plasticity and virus-mediated horizontal gene transfer in the microbial community. The manifestation of sulfur oxidation genes in hydrogen and methane oxidizing organisms hints at metabolic opportunism in deep-sea microbes that would enable them to respond to varying redox conditions in hydrothermal plumes. Finally, we infer that the abundance, diversity and metabolic versatility of microbes associated with sulfur oxidation impart functional redundancy that could allow it to persist in the dynamic settings of hydrothermal plumes.

Tail-robust scheduling using Limited Processor Sharing.

NARCIS (Netherlands)

Nair, J.K.; Wierman, A.; Zwart, A.P.

2010-01-01

From a rare events perspective, scheduling disciplines that work well under light (exponential) tailed workload distributions do not perform well under heavy (power) tailed workload distributions, and vice versa, leading to fundamental problems in designing schedulers that are robust to

Hydrothermal liquefaction of biomass

DEFF Research Database (Denmark)

Toor, Saqib; Rosendahl, Lasse; Rudolf, Andreas

2011-01-01

This article reviews the hydrothermal liquefaction of biomass with the aim of describing the current status of the technology. Hydrothermal liquefaction is a medium-temperature, high-pressure thermochemical process, which produces a liquid product, often called bio-oil or bi-crude. During...... the hydrothermal liquefaction process, the macromolecules of the biomass are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive and can recombine into larger ones. During this process, a substantial part of the oxygen in the biomass is removed...... by dehydration or decarboxylation. The chemical properties of bio-oil are highly dependent of the biomass substrate composition. Biomass constitutes of various components such as protein; carbohydrates, lignin and fat, and each of them produce distinct spectra of compounds during hydrothermal liquefaction...

Decision support tool for Virtual Power Players: Hybrid Particle Swarm Optimization applied to Day-ahead Vehicle-To-Grid Scheduling

DEFF Research Database (Denmark)

Soares, João; Valle, Zita; Morais, Hugo

2013-01-01

This paper presents a decision support Tool methodology to help virtual power players (VPPs) in the Smart Grid (SGs) context to solve the day-ahead energy ressource scheduling considering the intensive use of Distributed Generation (DG) and Vehicle-To-Grid (V2G). The main focus is the application...... of a new hybrid method combing a particle swarm approach and a deterministic technique based on mixedinteger linear programming (MILP) to solve the day-ahead scheduling minimizing total operation costs from the aggregator point of view. A realistic mathematical formulation, considering the electric network...... constraints and V2G charging and discharging efficiencies is presented. Full AC power flow calculation is included in the hybrid method to allow taking into account the network constraints. A case study with a 33-bus distribution network and 1800 V2G resources is used to illustrate the performance...

Economic power schedule and transactive energy through an intelligent centralized energy management system for a DC residential distribution system

DEFF Research Database (Denmark)

Yue, Jingpeng; Hu, Zhijian; Li, Chendan

2017-01-01

Direct current (DC) residential distribution systems (RDS) consisting of DC living homes will be a significant integral part of future green transmission. Meanwhile, the increasing number of distributed resources and intelligent devices will change the power flow between the main grid...... (CEMS), but also a control approach to implement and ensure DG output voltages to various DC buses in a DC RDS. Based on data collection, prediction and a certain objectives, the expert system in a CEMS can work out the optimization schedule, after this, the voltage droop control for steady voltage...... is aligned with the command of the unit power schedule. In this work, a DC RDS is used as a case study to demonstrate the process, the RDS is associated with unit economic models, and a cost minimization objective is proposed that is to be achieved based on the real-time electrical price. The results show...

Minimization of Load Variance in Power Grids—Investigation on Optimal Vehicle-to-Grid Scheduling

DEFF Research Database (Denmark)

Tan, Kang Miao; Ramachandaramurthy, Vigna K.; Yong, Jia Ying

2017-01-01

-to-grid optimization algorithm is implemented and tested in MATLAB software (R2013a, MathWorks, Natick, MA, USA). The performance of the optimization algorithm depends heavily on the setting of the target load, power grid load and capability of the grid-connected electric vehicles. Hence, the performance...... of the proposed algorithm under various target load and electric vehicles’ state of charge selections were analysed. The effectiveness of the vehicle-to-grid scheduling to implement the appropriate peak load shaving and load levelling services for the grid load variance minimization is verified under various...

Initial examination of the effects of overtime and shift scheduling on nuclear power plant safety performance

International Nuclear Information System (INIS)

Baker, K.; Olson, J.; Montgomery, J.

1990-01-01

The research reported here uses currently available data to begin to document overtime and shift scheduling practices in the nuclear industry and assess their safety consequences. Overtime and the 12-hour shift schedule have been found to affect employee fatigue and human error in other industries but neither of these practices have been systematically researched within the nuclear industry. Overtime has long been a standard practice in the nuclear industry and, recently, several licensees have adopted a 12-hour shift schedule for control room operations crews. Although 12-hour shifts have certain benefits for the employer and employee alike (e.g., can require fewer total employees and provide longer periods of time-off) there is some concern that the 12-hour shift may produce greater employee fatigue. Moreover, the 12-hour shift may exacerbate the negative effect of overtime. The potential effect of human error in the nuclear industry for the health and safety of both nuclear power plant workers and the general public requires that these practices be assessed. Data on overtime practices was obtained from the International Brotherhood of Electrical Workers (IBEW) for plants covered by the bargaining unit - approximately 63% of the total number of operating plants. Information on operator shift schedule was collected from all operating plants in 1987 by the NRC. The research produced fairly strong evidence that greater amounts of overtime worked by operators is associated with a greater number of operational problems

Hydrothermal Growth of Polyscale Crystals

Science.gov (United States)

Byrappa, Kullaiah

In this chapter, the importance of the hydrothermal technique for growth of polyscale crystals is discussed with reference to its efficiency in synthesizing high-quality crystals of various sizes for modern technological applications. The historical development of the hydrothermal technique is briefly discussed, to show its evolution over time. Also some of the important types of apparatus used in routine hydrothermal research, including the continuous production of nanosize crystals, are discussed. The latest trends in the hydrothermal growth of crystals, such as thermodynamic modeling and understanding of the solution chemistry, are elucidated with appropriate examples. The growth of some selected bulk, fine, and nanosized crystals of current technological significance, such as quartz, aluminum and gallium berlinites, calcite, gemstones, rare-earth vanadates, electroceramic titanates, and carbon polymorphs, is discussed in detail. Future trends in the hydrothermal technique, required to meet the challenges of fast-growing demand for materials in various technological fields, are described. At the end of this chapter, an Appendix 18.A containing a more or less complete list of the characteristic families of crystals synthesized by the hydrothermal technique is given with the solvent and pressure-temperature (PT) conditions used in their synthesis.

Distribution of hydrothermal fluid around the ore body in the subseafloor of the Izena hydrothermal field

Science.gov (United States)

Toki, T.; Otake, T.; Ishibashi, J. I.; Matsui, Y.; Kawagucci, S.; Kato, H.; Fuchida, S.; Miyahara, R.; Tsutsumi, A.; Kawakita, R.; Uza, H.; Uehara, R.; Shinjo, R.; Nozaki, T.; Kumagai, H.; Maeda, L.

2017-12-01

From 16th November to 15th December 2016, D/V Chikyu drilled the sea bottom around hydrothermal fields at HAKUREI site in the Izena Hole, Okinawa Trough. Site C9025, C9026, C9027, C9028, and C9032 are located along the transect line from the top of the northern mound of HAKUREI site to the eastward, and Site C9030 for the control site is located about 500 m northwest of the mound. Mg concentrations have generally been used to estimate mixing ratios between hydrothermal end-member and seawater in samples from hydrothermal vents. Higher Mg concentrations, however, were detected in the interstitial water than that of seawater, which could be due to artificially dissolution of Mg-bearing minerals that had formed in in-situ environments, when the cored sediments had become cool after their recovery on ship. Similar features were observed with regard to sulfate concentrations, and it suggests that these chemical species are not suitable to estimate quantitatively the contribution of hydrothermally-derived components. In some layers, chloride concentrations were different from that of seawater, indicating that hydrothermal fluids that had been suffered from phase separation flowed into the layers. The deviation, however, was positive or negative relative to that of seawater for an influence of brine or vapor phase, respectively. Therefore chloride concentrations are also not suitable to evaluate a quantitative contribution of hydrothermal end-member. On the other hand, K and B showed only enrichments relative to the seawater, and their highest concentrations are consistent with the reported hydrothermal end-members of each species at HAKUREI site. Using the concentrations of K and B can be evaluated for an influence of hydrothermal components. Furthermore, the headspace gas data are useful in the layers of sulfide minerals and silicified rocks, even though the interstitial waters could not be obtained because of their hardness. Based on these indices, hydrothermal fluids

Radiogeochemical features of hydrothermal metasomatic formations

International Nuclear Information System (INIS)

Plyushchev, E.V.; Ryabova, L.A.; Shatov, V.V.

1978-01-01

Considered are the most general peculiarities of uranium and thorium distributions in hydrothermal-metasomatic formations of three levels of substance formation: 1) in hydrothermal minerals; 2) in natural associations of these minerals (in the altered rocks, metasomatites, ores, etc.); 3) ordened series of zonally and in stage conjugated hydrothermal-metasomatic formations. Statistically stable recurrence of natural combinations of hydrothermal-metasomatic formations points out conjugation of their formation in the directed evolution in the general hydrothermal process. Series of metasomatic formations, the initial members of which are potassium metasomatites, mostly result in accumulation up to industrial concentrations of radioactive elements in final members of these formations. Development of midlow-temperature propylitic alterations in highly radiative rocks causes the same accumulation

Interaction between daily load demand curve and management of hydro-thermal generation system

International Nuclear Information System (INIS)

Granelli, G.; Montagna, M.; Pasini, G.; Innorta, M.; Marannino, P.

1993-01-01

The influence that the behaviour of the daily load demand curve has on the management of a hydro-thermal generation system is considered. The aim of this paper is to show the improvements that can be achieved by suitable load management techniques capable of flattening the load demand curve. The analysis is carried out by using a hydro-thermal scheduling program and a thermal unit dynamic dispatch procedure. The possibility of properly re-committing the available thermal units is also taken into account. The economical and technical convenience of shutting down less economical thermal units operating near the lower generations limits is verified. Finally, some considerations are made about the possible use of the thermal generation incremental costs as a tool for planning the end users' kWh prices, even in the short term. The results refer to a system with characteristics similar to those of the Italian one. In determining the daily load demand curves, the characteristics of load demand in Italy as well as in other European countries are taken into account

New tool for integration of wind power forecasting into power system operation

DEFF Research Database (Denmark)

Gubina, Andrej F.; Keane, Andrew; Meibom, Peter

2009-01-01

The paper describes the methodology that has been developed for transmission system operators (TSOs) of Republic of Ireland, Eirgrid, and Northern Ireland, SONI the TSO in Northern Ireland, to study the effects of advanced wind power forecasting on optimal short-term power system scheduling....... The resulting schedules take into account the electricity market conditions and feature optimal reserve scheduling. The short-term wind power prediction is provided by the Anemos tool, and the scheduling function, including the reserve optimisation, by the Wilmar tool. The proposed methodology allows...... for evaluation of the impacts that different types of wind energy forecasts (stochastic vs. deterministic vs. perfect) have on the schedules, and how the new incoming information via in-day scheduling impacts the quality of the schedules. Within the methodology, metrics to assess the quality of the schedules...

Dynamic Sleep Scheduling on Air Pollution Levels Monitoring with Wireless Sensor Network

Directory of Open Access Journals (Sweden)

Gezaq Abror

2018-01-01

Full Text Available Wireless Sensor Network (WSN can be applied for Air Pollution Level Monitoring System that have been determined by the Environmental Impact Management Agency which is  PM10, SO2, O3, NO2 and CO. In WSN, node system is constrained to a limited power supply, so that the node system has a lifetime. To doing lifetime maximization, power management scheme is required and sensor nodes should use energy efficiently. This paper proposes dynamic sleep scheduling using Time Category-Fuzzy Logic (Time-Fuzzy Scheduling as a reference for calculating time interval for sleep and activated node system to support power management scheme. This research contributed in power management design to be applied to the WSN system to reduce energy expenditure. From the test result in real hardware node system, it can be seen that Time-Fuzzy Scheduling is better in terms of using the battery and it is better in terms of energy consumption too because it is more efficient 51.85% when it is compared with Fuzzy Scheduling, it is more efficient 68.81% when it is compared with Standard Scheduling and it is more efficient 85.03% when compared with No Scheduling.

Cost effective shift schedules enhance utility operations

International Nuclear Information System (INIS)

Coleman, R.M.

1995-01-01

This article describes how new shift scheduling concepts can save utility operations millions of dollars every year and yet maintain safety and improve employee morale. The key to scheduling is to define and match the work load. This includes discretionary as well as daily, weekly, and yearly core work loads. In most power plants the overall work load (including maintenance, operations, materials handling, etc.) on day shift is greater than on other shifts, hence an unbalanced schedule would be appropriate

Seawater bicarbonate removal during hydrothermal circulation

Science.gov (United States)

Proskurowski, G. K.; Seewald, J.; Sylva, S. P.; Reeves, E.; Lilley, M. D.

2013-12-01

High temperature fluids sampled at hydrothermal vents represent a complex alteration product of water-rock reactions on a multi-component mixture of source fluids. Sources to high-temperature hydrothermal samples include the 'original' seawater present in the recharge limb of circulation, magmatically influenced fluids added at depth as well as any seawater entrained during sampling. High-temperature hydrothermal fluids are typically enriched in magmatic volatiles, with CO2 the dominant species, characterized by concentrations of 10's-100's of mmol/kg (1, 2). Typically, the high concentration of CO2 relative to background seawater bicarbonate concentrations (~2.3 mmol/kg) obscures a full analysis of the fate of seawater bicarbonate during high-temperature hydrothermal circulation. Here we present data from a suite of samples collected over the past 15 years from high-temperature hydrothermal vents at 9N, Endeavour, Lau Basin, and the MAR that have endmember CO2 concentrations less than 10 mmol/kg. Using stable and radiocarbon isotope measurements these samples provide a unique opportunity to examine the balance between 'original' seawater bicarbonate and CO2 added from magmatic sources. Multiple lines of evidence from multiple hydrothermal settings consistently points to the removal of ~80% of the 'original' 2.3 mmol/kg seawater bicarbonate. Assuming that this removal occurs in the low-temperature, 'recharge' limb of hydrothermal circulation, this removal process is widely occurring and has important contributions to the global carbon cycle over geologic time. 1. Lilley MD, Butterfield DA, Lupton JE, & Olson EJ (2003) Magmatic events can produce rapid changes in hydrothermal vent chemistry. Nature 422(6934):878-881. 2. Seewald J, Cruse A, & Saccocia P (2003) Aqueous volatiles in hydrothermal fluids from the Main Endeavour Field, northern Juan de Fuca Ridge: temporal variability following earthquake activity. Earth and Planetary Science Letters 216(4):575-590.

Magnetohydrodynamics MHD Engineering Test Facility ETF 200 MWe power plant. Conceptual Design Engineering Report CDER. Volume 3: Costs and schedules

Science.gov (United States)

1981-01-01

The estimated plant capital cost for a coal fired 200 MWE electric generating plant with open cycle magnetohydrodynamics is divided into principal accounts based on Federal Energy Regulatory Commision account structure. Each principal account is defined and its estimated cost subdivided into identifiable and major equipment systems. The cost data sources for compiling the estimates, cost parameters, allotments, assumptions, and contingencies, are discussed. Uncertainties associated with developing the costs are quantified to show the confidence level acquired. Guidelines established in preparing the estimated costs are included. Based on an overall milestone schedule related to conventional power plant scheduling experience and starting procurement of MHD components during the preliminary design phase there is a 6 1/2-year construction period. The duration of the project from start to commercial operation is 79 months. The engineering phase of the project is 4 1/2 years; the construction duration following the start of the man power block is 37 months.

A Bilevel Scheduling Approach for Modeling Energy Transaction of Virtual Power Plants in Distribution Networks

Directory of Open Access Journals (Sweden)

F. Nazari

2017-03-01

Full Text Available By increasing the use of distributed generation (DG in the distribution network operation, an entity called virtual power plant (VPP has been introduced to control, dispatch and aggregate the generation of DGs, enabling them to participate either in the electricity market or the distribution network operation. The participation of VPPs in the electricity market has made challenges to fairly allocate payments and benefits between VPPs and distribution network operator (DNO. This paper presents a bilevel scheduling approach to model the energy transaction between VPPs and DNO.  The upper level corresponds to the decision making of VPPs which bid their long- term contract prices so that their own profits are maximized and the lower level represents the DNO decision making to supply electricity demand of the network by minimizing its overall cost. The proposed bilevel scheduling approach is transformed to a single level optimizing problem using its Karush-Kuhn-Tucker (KKT optimality conditions. Several scenarios are applied to scrutinize the effectiveness and usefulness of the proposed model. 

Planning and Scheduling for Environmental Sensor Networks

Science.gov (United States)

Frank, J. D.

2005-12-01

Environmental Sensor Networks are a new way of monitoring the environment. They comprise autonomous sensor nodes in the environment that record real-time data, which is retrieved, analyzed, integrated with other data sets (e.g. satellite images, GIS, process models) and ultimately lead to scientific discoveries. Sensor networks must operate within time and resource constraints. Sensors have limited onboard memory, energy, computational power, communications windows and communications bandwidth. The value of data will depend on when, where and how it was collected, how detailed the data is, how long it takes to integrate the data, and how important the data was to the original scientific question. Planning and scheduling of sensor networks is necessary for effective, safe operations in the face of these constraints. For example, power bus limitations may preclude sensors from simultaneously collecting data and communicating without damaging the sensor; planners and schedulers can ensure these operations are ordered so that they do not happen simultaneously. Planning and scheduling can also ensure best use of the sensor network to maximize the value of collected science data. For example, if data is best recorded using a particular camera angle but it is costly in time and energy to achieve this, planners and schedulers can search for times when time and energy are available to achieve the optimal camera angle. Planning and scheduling can handle uncertainty in the problem specification; planners can be re-run when new information is made available, or can generate plans that include contingencies. For example, if bad weather may prevent the collection of data, a contingent plan can check lighting conditions and turn off data collection to save resources if lighting is not ideal. Both mobile and immobile sensors can benefit from planning and scheduling. For example, data collection on otherwise passive sensors can be halted to preserve limited power and memory

Chemical environments of submarine hydrothermal systems

Science.gov (United States)

Shock, Everett L.

1992-01-01

Perhaps because black-smoker chimneys make tremendous subjects for magazine covers, the proposal that submarine hydrothermal systems were involved in the origin of life has caused many investigators to focus on the eye-catching hydrothermal vents. In much the same way that tourists rush to watch the spectacular eruptions of Old Faithful geyser with little regard for the hydrology of the Yellowstone basin, attention is focused on the spectacular, high-temperature hydrothermal vents to the near exclusion of the enormous underlying hydrothermal systems. Nevertheless, the magnitude and complexity of geologic structures, heat flow, and hydrologic parameters which characterize the geyser basins at Yellowstone also characterize submarine hydrothermal systems. However, in the submarine systems the scale can be considerably more vast. Like Old Faithful, submarine hydrothermal vents have a spectacular quality, but they are only one fascinating aspect of enormous geologic systems operating at seafloor spreading centers throughout all of the ocean basins. A critical study of the possible role of hydrothermal processes in the origin of life should include the full spectrum of probable environments. The goals of this chapter are to synthesize diverse information about the inorganic geochemistry of submarine hydrothermal systems, assemble a description of the fundamental physical and chemical attributes of these systems, and consider the implications of high-temperature, fluid-driven processes for organic synthesis. Information about submarine hydrothermal systems comes from many directions. Measurements made directly on venting fluids provide useful, but remarkably limited, clues about processes operating at depth. The oceanic crust has been drilled to approximately 2.0 km depth providing many other pieces of information, but drilling technology has not allowed the bore holes and core samples to reach the maximum depths to which aqueous fluids circulate in oceanic crust. Such

Hydrothermal synthetic strategies of inorganic semiconducting nanostructures.

Science.gov (United States)

Shi, Weidong; Song, Shuyan; Zhang, Hongjie

2013-07-07

Because of their unique chemical and physical properties, inorganic semiconducting nanostructures have gradually played a pivotal role in a variety of research fields, including electronics, chemical reactivity, energy conversion, and optics. A major feature of these nanostructures is the quantum confinement effect, which strongly depends on their size, shape, crystal structure and polydispersity. Among all developed synthetic methods, the hydrothermal method based on a water system has attracted more and more attention because of its outstanding advantages, such as high yield, simple manipulation, easy control, uniform products, lower air pollution, low energy consumption and so on. Precise control over the hydrothermal synthetic conditions is a key to the success of the preparation of high-quality inorganic semiconducting nanostructures. In this review, only the representative hydrothermal synthetic strategies of inorganic semiconducting nanostructures are selected and discussed. We will introduce the four types of strategies based on exterior reaction system adjustment, namely organic additive- and template-free hydrothermal synthesis, organic additive-assisted hydrothermal synthesis, template-assisted hydrothermal synthesis and substrate-assisted hydrothermal synthesis. In addition, the two strategies based on exterior reaction environment adjustment, including microwave-assisted and magnetic field-assisted hydrothermal synthesis, will be also described. Finally, we conclude and give the future prospects of this research area.

Porosity evolution in Icelandic hydrothermal systems

Science.gov (United States)

Thien, B.; Kosakowski, G.; Kulik, D. A.

2014-12-01

Mineralogical alteration of reservoir rocks, driven by fluid circulation in natural or enhanced hydrothermal systems, is likely to influence the long-term performance of geothermal power generation. A key factor is the change of porosity due to dissolution of primary minerals and precipitation of secondary phases. Porosity changes will affect fluid circulation and solute transport, which, in turn, influence mineralogical alteration. This study is part of the Sinergia COTHERM project (COmbined hydrological, geochemical and geophysical modeling of geotTHERMal systems, grant number CRSII2_141843/1) that is an integrative research project aimed at improving our understanding of the sub-surface processes in magmatically-driven natural geothermal systems. These are typically high enthalphy systems where a magmatic pluton is located at a few kilometers depth. These shallow plutons increase the geothermal gradient and trigger the circulation of hydrothermal waters with a steam cap forming at shallow depth. Field observations suggest that active and fossil Icelandic hydrothermal systems are built from a superposition of completely altered and completely unaltered layers. With help of 1D and 2D reactive transport models (OpenGeoSys-GEM code), we investigate the reasons for this finding, by studying the mineralogical evolution of protoliths with different initial porosities at different temperatures and pressures, different leaching water composition and gas content, and different porosity geometries (i.e. porous medium versus fractured medium). From this study, we believe that the initial porosity of protoliths and volume changes due to their transformation into secondary minerals are key factors to explain the different alteration extents observed in field studies. We also discuss how precipitation and dissolution kinetics can influence the alteration time scales.

Improved Low Power FPGA Binding of Datapaths from Data Flow Graphs with NSGA II -based Schedule Selection

Directory of Open Access Journals (Sweden)

BHUVANESWARI, M. C.

2013-11-01

Full Text Available FPGAs are increasingly being used to implement data path intensive algorithms for signal processing and image processing applications. In High Level Synthesis of Data Flow Graphs targeted at FPGAs, the effect of interconnect resources such as multiplexers must be considered since they contribute significantly to the area and switching power. We propose a binding framework for behavioral synthesis of Data Flow Graphs (DFGs onto FPGA targets with power reduction as the main criterion. The technique uses a multi-objective GA, NSGA II for design space exploration to identify schedules that have the potential to yield low-power bindings from a population of non-dominated solutions. A greedy constructive binding technique reported in the literature is adapted for interconnect minimization. The binding is further subjected to a perturbation process by altering the register and multiplexer assignments. Results obtained on standard DFG benchmarks indicate that our technique yields better power aware bindings than the constructive binding approach with little or no area overhead.

Application of hydrothermally crystallized coal ashes for waste water treatment, 2

Energy Technology Data Exchange (ETDEWEB)

Kato, Yasuhiko; Kakimoto, Kohji; Ogawa, Hiroaki; Tomari, Masao; Sakamoto, Eiji; Asahara, Teruzo

1986-11-01

To provide an application of combustion coal ash, hydrothermal reaction of fly ash (FA) and clinker ash (CA) is performed and an investigation is carried out to determine the capability of the P type zeolite produced from these ashes to adsorb heavy metal ions. Hydrothermal reaction of FA and CA at 95 - 100 deg C is conducted with various concentrations of sodium hydroxide for various reaction times. Both types of ash are found to easily undergo crystallization to form P type zeolite (PZ) and hydroxy sodalite (HS) when treated with a sodium hydroxide solution (sodium hydroxide/coal ash = 10 v/w) for 18 hours. The FA-PZ and CA-PZ produced by the hydrothermal treatment have degrees of crystallinity in the range of 40 - 60 percent. It is seen that the degree of crystallinity gradually increases with increasing treatment time. The crystallinity of hydrothermally treated coal ash is also shown to have good correlation with the base substitution capacity and the maximum adsorption of ammonium ion. Furthermore, they are shown to effectively adsorb metal ions, in particular those of lead, cadmium and strontium. It is suggested that they may serve as an enrichment agent for low-level radioactive nuclides produced in nuclear power plants. They also seem to have the possibility of serving as a metal elution preventive for industrial wastes of some special types. (Nogami, K.).

Technology for planning and scheduling under complex constraints

Science.gov (United States)

Alguire, Karen M.; Pedro Gomes, Carla O.

1997-02-01

Within the context of law enforcement, several problems fall into the category of planning and scheduling under constraints. Examples include resource and personnel scheduling, and court scheduling. In the case of court scheduling, a schedule must be generated considering available resources, e.g., court rooms and personnel. Additionally, there are constraints on individual court cases, e.g., temporal and spatial, and between different cases, e.g., precedence. Finally, there are overall objectives that the schedule should satisfy such as timely processing of cases and optimal use of court facilities. Manually generating a schedule that satisfies all of the constraints is a very time consuming task. As the number of court cases and constraints increases, this becomes increasingly harder to handle without the assistance of automatic scheduling techniques. This paper describes artificial intelligence (AI) technology that has been used to develop several high performance scheduling applications including a military transportation scheduler, a military in-theater airlift scheduler, and a nuclear power plant outage scheduler. We discuss possible law enforcement applications where we feel the same technology could provide long-term benefits to law enforcement agencies and their operations personnel.

Optimal Power Scheduling for an Islanded Hybrid Microgrid

DEFF Research Database (Denmark)

Hernández, Adriana Carolina Luna; Aldana, Nelson Leonardo Diaz; Savaghebi, Mehdi

2016-01-01

model, wherein the disconnection of the load and not charging the battery when there is surplus of energy are penalized while physical constraints and requirements for a feasible deployment in the real system are considered. The proposed scheduling scheme is tested using a real-time control platform (d...

Dynamics of the Yellowstone hydrothermal system

Science.gov (United States)

Hurwitz, Shaul; Lowenstern, Jacob B.

2014-01-01

The Yellowstone Plateau Volcanic Field is characterized by extensive seismicity, episodes of uplift and subsidence, and a hydrothermal system that comprises more than 10,000 thermal features, including geysers, fumaroles, mud pots, thermal springs, and hydrothermal explosion craters. The diverse chemical and isotopic compositions of waters and gases derive from mantle, crustal, and meteoric sources and extensive water-gas-rock interaction at variable pressures and temperatures. The thermal features are host to all domains of life that utilize diverse inorganic sources of energy for metabolism. The unique and exceptional features of the hydrothermal system have attracted numerous researchers to Yellowstone beginning with the Washburn and Hayden expeditions in the 1870s. Since a seminal review published a quarter of a century ago, research in many fields has greatly advanced our understanding of the many coupled processes operating in and on the hydrothermal system. Specific advances include more refined geophysical images of the magmatic system, better constraints on the time scale of magmatic processes, characterization of fluid sources and water-rock interactions, quantitative estimates of heat and magmatic volatile fluxes, discovering and quantifying the role of thermophile microorganisms in the geochemical cycle, defining the chronology of hydrothermal explosions and their relation to glacial cycles, defining possible links between hydrothermal activity, deformation, and seismicity; quantifying geyser dynamics; and the discovery of extensive hydrothermal activity in Yellowstone Lake. Discussion of these many advances forms the basis of this review.

Scheduling for energy and reliability management on multiprocessor real-time systems

Science.gov (United States)

Qi, Xuan

Scheduling algorithms for multiprocessor real-time systems have been studied for years with many well-recognized algorithms proposed. However, it is still an evolving research area and many problems remain open due to their intrinsic complexities. With the emergence of multicore processors, it is necessary to re-investigate the scheduling problems and design/develop efficient algorithms for better system utilization, low scheduling overhead, high energy efficiency, and better system reliability. Focusing cluster schedulings with optimal global schedulers, we study the utilization bound and scheduling overhead for a class of cluster-optimal schedulers. Then, taking energy/power consumption into consideration, we developed energy-efficient scheduling algorithms for real-time systems, especially for the proliferating embedded systems with limited energy budget. As the commonly deployed energy-saving technique (e.g. dynamic voltage frequency scaling (DVFS)) will significantly affect system reliability, we study schedulers that have intelligent mechanisms to recuperate system reliability to satisfy the quality assurance requirements. Extensive simulation is conducted to evaluate the performance of the proposed algorithms on reduction of scheduling overhead, energy saving, and reliability improvement. The simulation results show that the proposed reliability-aware power management schemes could preserve the system reliability while still achieving substantial energy saving.

Coordination between Generation and Transmission Maintenance Scheduling by Means of Multi-agent Technique

Science.gov (United States)

Nagata, Takeshi; Tao, Yasuhiro; Utatani, Masahiro; Sasaki, Hiroshi; Fujita, Hideki

This paper proposes a multi-agent approach to maintenance scheduling in restructured power systems. The restructuring of electric power industry has resulted in market-based approaches for unbundling a multitude of service provided by self-interested entities such as power generating companies (GENCOs), transmission providers (TRANSCOs) and distribution companies (DISCOs). The Independent System Operator (ISO) is responsible for the security of the system operation. The schedule submitted to ISO by GENCOs and TRANSCOs should satisfy security and reliability constraints. The proposed method consists of several GENCO Agents (GAGs), TARNSCO Agents (TAGs) and a ISO Agent(IAG). The IAG’s role in maintenance scheduling is limited to ensuring that the submitted schedules do not cause transmission congestion or endanger the system reliability. From the simulation results, it can be seen the proposed multi-agent approach could coordinate between generation and transmission maintenance schedules.

Scheduling the scheduling task : a time management perspective on scheduling

NARCIS (Netherlands)

Larco Martinelli, J.A.; Wiers, V.C.S.; Fransoo, J.C.

2013-01-01

Time is the most critical resource at the disposal of schedulers. Hence, an adequate management of time from the schedulers may impact positively on the scheduler’s productivity and responsiveness to uncertain scheduling environments. This paper presents a field study of how schedulers make use of

Fluid transfer and vein thickness distribution in high and low temperature hydrothermal systems at shallow crustal level in southern Tuscany (Italy

Directory of Open Access Journals (Sweden)

Francesco Mazzarini

2014-06-01

Full Text Available Geometric analysis of vein systems hosted in upper crustal rocks and developed in high and low temperature hydrothermal systems is presented. The high temperature hydrothermal system consists of tourmaline-rich veins hosted within the contact aureole of the upper Miocene Porto Azzurro pluton in the eastern Elba Island. The low temperature hydrothermal system consists of calcite-rich veins hosted within the Oligocene sandstones of the Tuscan Nappe, exposed along the coast in southern Tuscany. Vein thickness distribution is here used as proxy for inferring some hydraulic properties (transmissivity of the fluid circulation at the time of veins’ formation. We derive estimations of average thickness of veins by using the observed distributions. In the case of power law thickness distributions, the lower the scaling exponent of the distribution the higher the overall transmissivity. Indeed, power law distributions characterised by high scaling exponents have transmissivity three order of magnitude lower than negative exponential thickness distribution. Simple observations of vein thickness may thus provides some clues on the transmissivity in hydrothermal systems.

A Heuristic Task Scheduling Algorithm for Heterogeneous Virtual Clusters

Directory of Open Access Journals (Sweden)

Weiwei Lin

2016-01-01

Full Text Available Cloud computing provides on-demand computing and storage services with high performance and high scalability. However, the rising energy consumption of cloud data centers has become a prominent problem. In this paper, we first introduce an energy-aware framework for task scheduling in virtual clusters. The framework consists of a task resource requirements prediction module, an energy estimate module, and a scheduler with a task buffer. Secondly, based on this framework, we propose a virtual machine power efficiency-aware greedy scheduling algorithm (VPEGS. As a heuristic algorithm, VPEGS estimates task energy by considering factors including task resource demands, VM power efficiency, and server workload before scheduling tasks in a greedy manner. We simulated a heterogeneous VM cluster and conducted experiment to evaluate the effectiveness of VPEGS. Simulation results show that VPEGS effectively reduced total energy consumption by more than 20% without producing large scheduling overheads. With the similar heuristic ideology, it outperformed Min-Min and RASA with respect to energy saving by about 29% and 28%, respectively.

Economic power schedule and transactive energy through an intelligent centralized energy management system for a DC residential distribution system

DEFF Research Database (Denmark)

Yue, Jingpeng; Hu, Zhijian; Li, Chendan

2017-01-01

and the demand side. The utilization of distributed generation (DG) requires an economic operation, stability, and an environmentally friendly approach in the whole DC system. This paper not only presents an optimization schedule and transactive energy (TE) approach through a centralized energy management system...... is aligned with the command of the unit power schedule. In this work, a DC RDS is used as a case study to demonstrate the process, the RDS is associated with unit economic models, and a cost minimization objective is proposed that is to be achieved based on the real-time electrical price. The results show...... that the proposed framework and methods will help the targeted DC residential system to reduce the total cost and reach stability and efficiency....

ESR dating of submarine hydrothermal activities using barite in sulfide deposition

Science.gov (United States)

Toyoda, S.; Fujiwara, T.; Ishibashi, J.; Isono, Y.; Uchida, A.; Takamasa, A.; Nakai, S.

2012-12-01

The temporal change of submarine hydrothermal activities has been an important issue in the aspect of the evolution of hydrothermal systems which is related with ore formation (Urabe, 1995) and biological systems sustained by the chemical species arising from hydrothermal activities (Macdonald et al., 1980). Determining the ages of the hydrothermal deposit will provide essential information on such studies. Dating methods using disequilibrium between radioisotopes such as U-Th method (e.g. You and Bickle, 1998), 226}Ra-{210Pb and 228}Ra-{228Th method (e.g. Noguchi et al., 2011) have been applied to date submarine hydrothermal deposits. ESR (electron spin resonance) dating method is commonly applied to fossil teeth, shells, and quartz of Quaternay period where the natural accumulated dose is obtained from the intensities of the ESR signals which are created by natural radiation. The natural dose is divided by the dose rate to the mineral/sample to deduce the age. Okumura et al., (2010) made the first practical application of ESR (electron spin resonance) dating technique to a sample of submarine hydrothermal barite (BaSO4) to obtain preliminary ages, where Kasuya et al. (1991) first pointed out that barite can be used for ESR dating. Knowing that ESR dating of barite is promising, in this paper, we will present how we have investigated each factor that contributes ESR dating of barite in submarine hydrothermal sulfide deposition. (1) The best ESR condition for measuring the SO3- signal in barite is with the microwave power of 1mW and modulation amplitude of 0.1mT. (2) As results of heating experiments, the signal was found to be stable for the dating age range of several thousands. (3) 226Ra replacing Ba in barite is the source of the radiation. The amount of radioactive elements in sulfide mineral surrounding barite is negligible. (4) The external radiation from the sea water is negligible even in the submarine hydrothermal area where the radiation level is much

Optimal scheduling of coproduction with a storage

International Nuclear Information System (INIS)

Ravn, H.F.; Rygard, J.M.

1993-02-01

We consider the problem of optimal scheduling of a system with combined heat and heat (CHP) units and a heat storege. The purpose of the heat storage is to permit a partial decoupling of the variations in the demand for heat and electrical power. We formulate the problem of optimal scheduling as that of minimizing the total costs over the planning period. The heat demand from the district heating system and the ''shadow prices'' for the electrical power system are taken as externally given parameters. The resulting model is solved by dynamic programming. We describe implementation details and we give examples of result of the optimization. (au) (12 refs.)

The Guaymas Basin hiking guide to hydrothermal mounds, chimneys and microbial mats: complex seafloor expressions of subsurface hydrothermal circulation

Directory of Open Access Journals (Sweden)

Andreas eTeske

2016-02-01

Full Text Available The hydrothermal mats, mounds and chimneys of the southern Guaymas Basin are the surface expression of complex subsurface hydrothermal circulation patterns. In this overview we document the most frequently visited features of this hydrothermal area with photographs, temperature measurements, and selected geochemical data; many of these distinct habitats await characterization of their microbial communities and activities. Microprofiler deployments on microbial mats and hydrothermal sediments show their steep geochemical and thermal gradients at millimeter-scale vertical resolution. Mapping these hydrothermal features and sampling locations within the southern Guaymas Basin suggest linkages to underlying shallow sills and heatflow gradients. Recognizing the inherent spatial limitations of much current Guaymas Basin sampling calls for a wider survey of the entire spreading region.

Schedule of the nuclear program

International Nuclear Information System (INIS)

Heigl, F.

1977-01-01

The lecure tries to explain the main phases which must be passed to establish nuclear power plants, the feasibility phase, preconstruction and construction phase. Each phase consists of a lot of activities which are commented. Further the lecture tries to give some ideas of durances and dependence between the phases or activities to get a complete time schedule of the realization of a nuclear power project. (HP) [de

Modelling of hydrothermal characteristics of centrifugal nozzles

International Nuclear Information System (INIS)

Yarkho, A.A.; Omelchenko, M.P.; Borshchev, V.A.

1990-01-01

Presented for the first time is a method of recalculating the hydrothermal characteristics of centrifugal nozzles obtained in laboratory conditions for full-scale nozzles. From the experimental hydrothermal characteristics of nozzles observed in the laboratory it is allowed to calculate the hydrothermal characteristics of any other centrifugal nozzle whose diameter and dimensionless geometric characteristic are known

Nuclear Power Prospects

International Nuclear Information System (INIS)

Cintra do Prado, L.

1966-01-01

The present trend is to construct larger plants: the average power of the plants under construction at present, including prototypes, is 300 MW(e), i.e. three times higher than in the case of plants already in operation. Examples of new large-scale plants ares (a) Wylfa, Anglesey, United Kingdom - scheduled power of 1180 MW(e) (800 MW to be installed by 1967), to be completed in 1968; (b) ''Dungeness B'', United Kingdom - scheduled power of 1200 MW(e); (c) second unit for United States Dresden power plant - scheduled power of 715 MW(e) minimum to almost 800 MW(e). Nuclear plants on the whole serve the same purpose as conventional thermal plants

Study on the hydrothermal treatment of Shenhua coal

Energy Technology Data Exchange (ETDEWEB)

Zhicai Wang; Hengfu Shui; Zhanning Pei; Jinsheng Gao [Anhui University of Technology, Ma' anshan (China). School of Chemistry and Chemical Engineering

2008-04-15

In this paper, the hydrothermal treatment of Shenhua coal was carried out under 0.1 MPa (initial pressure) nitrogen and different temperature. Effects of hydrothermal treatment on the structure and the hydro-liquefaction activity of Shenhua coal were investigated by the ultimate and proximate analyses, the FTIR measurements and TG analyses of hydrothermally treated coals, and the characterizations of extraction and swelling properties, and the batch hydro-liquefaction of treated coal were also carried out. The results indicate that hydrothermal treatment above 200{sup o}C can increase the hydrogen content of treated coal and decrease the yield of volatiles and the content of ash, especially a large amount of CO and CH{sub 4} are found in gas products obtained by the hydrothermal treatment above 250{sup o}C. Hydrothermal treatment disrupts the weak covalent bond such as ether, ester and side-chain substituent by hydrolysis and pyrolysis, and changes the distribution of H-bond in coal. The swelling ratio and the Soxhlet extraction yield of treated coal decrease with the increase of hydrothermal treatment temperature. The conversion of liquefaction and the yield of CS{sub 2}/NMP mixed solvent extraction at ambient temperature are enhanced by hydrothermal treatment at 300{sup o}C. Therefore hydrogen donation reactions and the rupture of non-covalent bond and weak covalent bonds present in the process of hydrothermal treatment resulting in the changes of structure and reactivity of Shenhua coal. The results show that the hydro-liquefaction activity of Shenhua coal can be improved by hydrothermal pretreatment between 250{sup o}C and 300{sup o}C. 15 refs., 5 figs., 4 tabs.

Reconstruction of Ancestral Hydrothermal Systems on Mount Rainier Using Hydrothermally Altered Rocks in Holocene Debris Flows and Tephras

Science.gov (United States)

John, D. A.; Breit, G. N.; Sisson, T. W.; Vallance, J. W.; Rye, R. O.

2005-12-01

Mount Rainier is the result of episodic stages of edifice growth during periods of high eruptive activity and edifice destruction during periods of relative magmatic quiescence over the past 500 kyr. Edifice destruction occurred both by slow erosion and by catastrophic collapses, some of which were strongly influenced by hydrothermal alteration. Several large-volume Holocene debris-flow deposits contain abundant clasts of hydrothermally altered rocks, most notably the 4-km3 clay-rich Osceola Mudflow which formed by collapse of the northeast side and upper 1000+ m of the edifice about 5600 ya and flowed >120 km downstream into Puget Sound. Mineral assemblages and stable isotope data of hydrothermal alteration products in Holocene debris-flow deposits indicate formation in distinct hydrothermal environments, including magmatic-hydrothermal, steam-heated (including a large fumarolic component), magmatic steam (including a possible fumarolic component), and supergene. The Osceola Mudflow and phreatic components of coeval tephras contain the highest-temperature and inferred most deeply formed alteration minerals; assemblages include magmatic-hydrothermal quartz-alunite, quartz-topaz, quartz-pyrophyllite and quartz-illite (all +pyrite), in addition to steam-heated opal-alunite-kaolinite and abundant smectite-pyrite. In contrast, the Paradise lahar, which formed by a collapse of the surficial upper south side of the edifice, contains only steam-heated assemblages including those formed largely above the water table from condensation of fumarolic vapor (opal-alunite-jarosite). Younger debris-flow deposits on the west side of the volcano (Round Pass lahar and Electron Mudflow) contain only smectite-pyrite alteration, whereas an early 20th century rock avalanche on Tahoma Glacier also contains magmatic-hydrothermal alteration that is exposed in the avalanche headwall of Sunset Amphitheater. Mineralogy and isotopic composition of the alteration phases, geologic and

Application of Hydrothermal and Non-Hydrothermal TiO2 Nanoporous Materials as New Adsorbents for Removal of Heavy Metal Ions from Aqueous System

Directory of Open Access Journals (Sweden)

Mansoor Anbia

2016-06-01

Full Text Available Hydrothermal and non-hydrothermal spherical TiO2 nanoporous with crystalline framework were prepared by sol-gel method. The Crystalline structures, morphologies and surface texturing of materials were determined by X-ray diffraction (XRD, scanning electron microscopy (SEM and N2 adsorption-desorption isotherms. The Hydrothermal spherical TiO2 nanoporous was found to have a narrow and strong pore size distribution peaks with average of 37.8 Å and pore volume of 0.41 cm3/g and the (Brunauer–Emmett–TellerBET specific surface area of 365 m2/g. Hydrothermal and non-hydrothermal spherical TiO2 nanoporous have been used as adsorbent to study of the adsorption behavior of Pb(II, Co(II and Ni(II ions from aqueous system in a batch system. Effect of equilibrium time on adsorption Pb(II, Co(II and Ni(II ions on these adsorbent was studied The results show that the shaking time 0.5 to 10h has no serious effect on the percentage of ions removal, and the adsorption is fast in all cases. The maximum uptake capacities of Hydrothermal and non-hydrothermal spherical TiO2 nanoporous was calculated. Both hydrothermal and non-hydrothermal TiO2 nanoporous materials were found to have very good potential as new adsorbents in removal of these ions. In batch systems the maximum uptake capacities of Pb(II, Ni(II and Co(II on the hydrothermal and non-hydrothermal TiO2 nanoporous materials was Co(II > Pb(II > Ni(II and Co(II > Ni(II > Pb(II, respectively.

Evaluation of utility monitoring and preoperational hydrothermal modeling at three nuclear power plant sites

International Nuclear Information System (INIS)

Marmer, G.J.; Policastro, A.J.

1977-01-01

This paper evaluates the preoperational hydrothermal modeling and operational monitoring carried out by utilities as three nuclear-power-plant sites using once-through cooling. Our work was part of a larger study to assess the environmental impact of operating plants for the Nuclear Regulatory Commission (NRC) and the suitability of the NRC Environmental Technical Specifications (Tech Specs) as set up for these plants. The study revealed that the plume mappings at the Kewaunee, Zion, and Quad Cities sites were generally satisfactory in terms of delineating plume size and other characteristics. Unfortunately, monitoring was not carried out during the most critical periods when largest plume size would be expected. At Kewaunee and Zion, preoperational predictions using analytical models were found to be rather poor. At Kewaunee (surface discharge), the Pritchard Model underestimated plume size in the near field, but grossly overestimated the plume's far-field extent. Moreover, lake-level variations affected plume dispersion, yet were not considered in preoperational predictions. At Zion (submerged discharge) the Pritchard Model was successful only in special, simple cases (single-unit operation, no stratification, no reversing currents, no recirculation). Due to neglect of the above-mentioned phenomena, the model underpredicted plume size. At Quad Cities (submerged discharge), the undistorted laboratory model predicted plume dispersion for low river flows. These low flow predictions appear to be reasonable extrapolations of the field data acquired at higher flows

Scheduling algorithms for saving energy and balancing load

Energy Technology Data Exchange (ETDEWEB)

Antoniadis, Antonios

2012-08-03

In this thesis we study problems of scheduling tasks in computing environments. We consider both the modern objective function of minimizing energy consumption, and the classical objective of balancing load across machines. We first investigate offline deadline-based scheduling in the setting of a single variable-speed processor that is equipped with a sleep state. The objective is that of minimizing the total energy consumption. Apart from settling the complexity of the problem by showing its NP-hardness, we provide a lower bound of 2 for general convex power functions, and a particular natural class of schedules called s{sub crit}-schedules. We also present an algorithmic framework for designing good approximation algorithms. For general convex power functions our framework improves the best known approximation-factor from 2 to 4/3. This factor can be reduced even further to 137/117 for a specific well-motivated class of power functions. Furthermore, we give tight bounds to show that our framework returns optimal s{sub crit}-schedules for the two aforementioned power-function classes. We then focus on the multiprocessor setting where each processor has the ability to vary its speed. Job migration is allowed, and we again consider classical deadline-based scheduling with the objective of energy minimization. We first study the offline problem and show that optimal schedules can be computed efficiently in polynomial time for any convex and non-decreasing power function. Our algorithm relies on repeated maximum flow computations. Regarding the online problem and power functions P(s) = s{sup {alpha}}, where s is the processor speed and {alpha} > 1 a constant, we extend the two well-known single-processor algorithms Optimal Available and Average Rate. We prove that Optimal Available is {alpha}{sup {alpha}}-competitive as in the single-processor case. For Average Rate we show a competitive factor of (2{alpha}){sup {alpha}}/2 + 1, i.e., compared to the single

Ideas and perspectives: hydrothermally driven redistribution and sequestration of early Archaean biomass - the "hydrothermal pump hypothesis"

Science.gov (United States)

Duda, Jan-Peter; Thiel, Volker; Bauersachs, Thorsten; Mißbach, Helge; Reinhardt, Manuel; Schäfer, Nadine; Van Kranendonk, Martin J.; Reitner, Joachim

2018-03-01

Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic). In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga Dresser Formation (Pilbara Craton, Western Australia). Catalytic hydropyrolysis (HyPy) of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. This distribution ( ≤ n-C18) is very similar to that observed in HyPy products of recent bacterial biomass, which was used as reference material, whereas it differs markedly from the unimodal distribution of abiotic compounds experimentally formed via Fischer-Tropsch-type synthesis. We therefore propose that the organic matter in the Archaean chert veins has a primarily microbial origin. The microbially derived organic matter accumulated in anoxic aquatic (surface and/or subsurface) environments and was then assimilated, redistributed and sequestered by the hydrothermal fluids (hydrothermal pump hypothesis).

Best Speed Fit EDF Scheduling for Performance Asymmetric Multiprocessors

Directory of Open Access Journals (Sweden)

Peng Wu

2017-01-01

Full Text Available In order to improve the performance of a real-time system, asymmetric multiprocessors have been proposed. The benefits of improved system performance and reduced power consumption from such architectures cannot be fully exploited unless suitable task scheduling and task allocation approaches are implemented at the operating system level. Unfortunately, most of the previous research on scheduling algorithms for performance asymmetric multiprocessors is focused on task priority assignment. They simply assign the highest priority task to the fastest processor. In this paper, we propose BSF-EDF (best speed fit for earliest deadline first for performance asymmetric multiprocessor scheduling. This approach chooses a suitable processor rather than the fastest one, when allocating tasks. With this proposed BSF-EDF scheduling, we also derive an effective schedulability test.

Energy landscapes shape microbial communities in hydrothermal systems on the Arctic Mid-Ocean Ridge.

Science.gov (United States)

Dahle, Håkon; Økland, Ingeborg; Thorseth, Ingunn H; Pederesen, Rolf B; Steen, Ida H

2015-07-01

Methods developed in geochemical modelling combined with recent advances in molecular microbial ecology provide new opportunities to explore how microbial communities are shaped by their chemical surroundings. Here, we present a framework for analyses of how chemical energy availability shape chemotrophic microbial communities in hydrothermal systems through an investigation of two geochemically different basalt-hosted hydrothermal systems on the Arctic Mid-Ocean Ridge: the Soria Moria Vent field (SMVF) and the Loki's Castle Vent Field (LCVF). Chemical energy landscapes were evaluated through modelling of the Gibbs energy from selected redox reactions under different mixing ratios between seawater and hydrothermal fluids. Our models indicate that the sediment-influenced LCVF has a much higher potential for both anaerobic and aerobic methane oxidation, as well as aerobic ammonium and hydrogen oxidation, than the SMVF. The modelled energy landscapes were used to develop microbial community composition models, which were compared with community compositions in environmental samples inside or on the exterior of hydrothermal chimneys, as assessed by pyrosequencing of partial 16S rRNA genes. We show that modelled microbial communities based solely on thermodynamic considerations can have a high predictive power and provide a framework for analyses of the link between energy availability and microbial community composition.

Optimal hydro scheduling and offering strategies considering price uncertainty and risk management

International Nuclear Information System (INIS)

Catalão, J.P.S.; Pousinho, H.M.I.; Contreras, J.

2012-01-01

Hydro energy represents a priority in the energy policy of Portugal, with the aim of decreasing the dependence on fossil fuels. In this context, optimal hydro scheduling acquires added significance in moving towards a sustainable environment. A mixed-integer nonlinear programming approach is considered to enable optimal hydro scheduling for the short-term time horizon, including the effect of head on power production, start-up costs related to the units, multiple regions of operation, and constraints on discharge variation. As new contributions to the field, market uncertainty is introduced in the model via price scenarios and risk management is included using Conditional Value-at-Risk to limit profit volatility. Moreover, plant scheduling and pool offering by the hydro power producer are simultaneously considered to solve a realistic cascaded hydro system. -- Highlights: ► A mixed-integer nonlinear programming approach is considered for optimal hydro scheduling. ► Market uncertainty is introduced in the model via price scenarios. ► Risk management is included using conditional value-at-risk. ► Plant scheduling and pool offering by the hydro power producer are simultaneously considered. ► A realistic cascaded hydro system is solved.

Attitudes of the general public and electric power company employees toward nuclear power generation

International Nuclear Information System (INIS)

Komiyama, Hisashi

1997-01-01

We conducted an awareness survey targeted at members of the general public residing in urban areas and in areas scheduled for construction of nuclear power plants as well as employees of electric power company in order to determine the awareness and attitude structures of people residing near scheduled construction sites of nuclear power plants with respect to nuclear power generation, and to examine ways of making improvements in terms of promoting nuclear power plant construction sites. Analysis of those results revealed that there are no significant differences in the awareness and attitudes of people residing in urban areas and in areas near scheduled construction sites. On the contrary, a general sense of apprehension regarding the construction of nuclear power plants was observed common to both groups. In addition, significant differences in awareness and attitudes with respect to various factors were determined to exist between members of the general public residing in urban areas and scheduled construction sites and employees of electric power company. (author)

Using the principles of circadian physiology enhances shift schedule design

International Nuclear Information System (INIS)

Connolly, J.J.; Moore-Ede, M.C.

1987-01-01

Nuclear power plants must operate 24 h, 7 days a week. For the most part, shift schedules currently in use at nuclear power plants have been designed to meet operational needs without considering the biological clocks of the human operators. The development of schedules that also take circadian principles into account is a positive step that can be taken to improve plant safety by optimizing operator alertness. These schedules reduce the probability of human errors especially during backshifts. In addition, training programs that teach round-the-clock workers how to deal with the problems of shiftwork can help to optimize performance and alertness. These programs teach shiftworkers the underlying causes of the sleep problems associated with shiftwork and also provide coping strategies for improving sleep and dealing with the transition between shifts. When these training programs are coupled with an improved schedule, the problems associated with working round-the-clock can be significantly reduced

Hydrothermal treatment followed by enzymatic hydrolysis and hydrothermal carbonization as means to valorise agro- and forest-based biomass residues.

Science.gov (United States)

Wikberg, Hanne; Grönqvist, Stina; Niemi, Piritta; Mikkelson, Atte; Siika-Aho, Matti; Kanerva, Heimo; Käsper, Andres; Tamminen, Tarja

2017-07-01

The suitability of several abundant but underutilized agro and forest based biomass residues for hydrothermal treatment followed by enzymatic hydrolysis as well as for hydrothermal carbonization was studied. The selected approaches represent simple biotechnical and thermochemical treatment routes suitable for wet biomass. Based on the results, the hydrothermal pre-treatment followed by enzymatic hydrolysis seemed to be most suitable for processing of carbohydrate rich corn leaves, corn stover, wheat straw and willow. High content of thermally stable components (i.e. lignin) and low content of ash in the biomass were advantageous for hydrothermal carbonization of grape pomace, coffee cake, Scots pine bark and willow. Copyright © 2017 Elsevier Ltd. All rights reserved.

Scheduling Non-Preemptible Jobs to Minimize Peak Demand

Directory of Open Access Journals (Sweden)

Sean Yaw

2017-10-01

Full Text Available This paper examines an important problem in smart grid energy scheduling; peaks in power demand are proportionally more expensive to generate and provision for. The issue is exacerbated in local microgrids that do not benefit from the aggregate smoothing experienced by large grids. Demand-side scheduling can reduce these peaks by taking advantage of the fact that there is often flexibility in job start times. We focus attention on the case where the jobs are non-preemptible, meaning once started, they run to completion. The associated optimization problem is called the peak demand minimization problem, and has been previously shown to be NP-hard. Our results include an optimal fixed-parameter tractable algorithm, a polynomial-time approximation algorithm, as well as an effective heuristic that can also be used in an online setting of the problem. Simulation results show that these methods can reduce peak demand by up to 50% versus on-demand scheduling for household power jobs.

Power Constrained High-Level Synthesis of Battery Powered Digital Systems

DEFF Research Database (Denmark)

Nielsen, Sune Fallgaard; Madsen, Jan

2003-01-01

We present a high-level synthesis algorithm solving the combined scheduling, allocation and binding problem minimizing area under both latency and maximum power per clock-cycle constraints. Our approach eliminates the large power spikes, resulting in an increased battery lifetime, a property...... of utmost importance for battery powered embedded systems. Our approach extends the partial-clique partitioning algorithm by introducing power awareness through a heuristic algorithm which bounds the design space to those of power feasible schedules. We have applied our algorithm on a set of dataflow graphs...

Market Power in Hydro-Thermal Supply

International Nuclear Information System (INIS)

Edin, Karl-Axel

2006-12-01

Despite having had a deregulated electricity market in Sweden for over ten years we still need to increase our understanding as to how deregulated electricity markets actually work and how possible problems are to be solved. One question that is always in focus is if the competition between generators in the Nordic electricity market really works the way it was intended. Many argue that the concentration in ownership of generation plants already has gone too far. Together with joint ownership in nuclear facilities and barriers for entrance, critics say that this has resulted in higher electricity prices than necessary. In this report different methods to (ex ante) study potential possibilities for generating firms to influence the electricity price (market power) and (ex post) discover possible manipulation through analysing the spot price and other observed factors on the electricity market are analysed. The purpose of the longer underlying paper is to give a comprehensive treatment of the electricity market with storage, i.e. hydro power, with an auction market organisation and to test the models on the Nordic market in order to explore the explanatory power of auction market theory and the theory of contestable market. The main theoretical effort in the paper concerns auction theory with inventories. The paper develops an inter-temporal auction model of a thermal-hydro power market. Parallel to the derivation of the basic equations a numerical model is developed in order to illustrate the results of the model. Section 2 of the present paper summarizes the basic equations (derived in the longer paper) for an inter-temporal auction thermal-hydro market. Section 3 contains the illustrations of solutions to equations for some stylized markets. In section 4 the auction model is tested on the Nordic market

Home Appliance Load Scheduling with SEMIAH

DEFF Research Database (Denmark)

Jacobsen, Rune Hylsberg; Ghasem Azar, Armin; Zhang, Qi

2015-01-01

The European research project SEMIAH aims at designing a scalable infrastructure for residential demand response. This paper presents the progress towards a centralized load scheduling algorithm for controlling home appliances taking power grid constraints and satisfaction of consumers into account....

Optimal Scheduling of Domestic Appliances via MILP

Directory of Open Access Journals (Sweden)

Zdenek Bradac

2014-12-01

Full Text Available This paper analyzes a consumption scheduling mechanism for domestic appliances within a home area network. The aim of the proposed scheduling is to minimize the total energy price paid by the consumer and to reduce power peaks in order to achieve a balanced daily load schedule. An exact and computationally efficient mixed-integer linear programming (MILP formulation of the problem is presented. This model is verified by several problem instances. Realistic scenarios based on the real price tariffs commercially available in the Czech Republic are calculated. The results obtained by solving the optimization problem are compared with a simulation of the ripple control service currently used by many domestic consumers in the Czech Republic.

A Hierarchical Algorithm for Integrated Scheduling and Control With Applications to Power Systems

DEFF Research Database (Denmark)

Sokoler, Leo Emil; Dinesen, Peter Juhler; Jørgensen, John Bagterp

2016-01-01

The contribution of this paper is a hierarchical algorithm for integrated scheduling and control via model predictive control of hybrid systems. The controlled system is a linear system composed of continuous control, state, and output variables. Binary variables occur as scheduling decisions in ...

Coordinated scheduling for the downlink of cloud radio-access networks

KAUST Repository

Douik, Ahmed S.

2015-09-11

This paper addresses the coordinated scheduling problem in cloud-enabled networks. Consider the downlink of a cloud-radio access network (CRAN), where the cloud is only responsible for the scheduling policy and the synchronization of the transmit frames across the connected base-stations (BS). The transmitted frame of every BS consists of several time/frequency blocks, called power-zones (PZ), maintained at fixed transmit power. The paper considers the problem of scheduling users to PZs and BSs in a coordinated fashion across the network, by maximizing a network-wide utility under the practical constraint that each user cannot be served by more than one base-station, but can be served by one or more power-zones within each base-station frame. The paper solves the problem using a graph theoretical approach by introducing the scheduling graph in which each vertex represents an association of users, PZs and BSs. The problem is formulated as a maximum weight clique, in which the weight of each vertex is the benefit of the association represented by that vertex. The paper further presents heuristic algorithms with low computational complexity. Simulation results show the performance of the proposed algorithms and suggest that the heuristics perform near optimal in low shadowing environments. © 2015 IEEE.

Whole Algae Hydrothermal Liquefaction Technology Pathway

Energy Technology Data Exchange (ETDEWEB)

Biddy, M.; Davis, R.; Jones, S.

2013-03-01

This technology pathway case investigates the feasibility of using whole wet microalgae as a feedstock for conversion via hydrothermal liquefaction. Technical barriers and key research needs have been assessed in order for the hydrothermal liquefaction of microalgae to be competitive with petroleum-derived gasoline-, diesel-, and jet-range hydrocarbon blendstocks.

Distributed and Cooperative Link Scheduling for Large-Scale Multihop Wireless Networks

Directory of Open Access Journals (Sweden)

Swami Ananthram

2007-01-01

Full Text Available A distributed and cooperative link-scheduling (DCLS algorithm is introduced for large-scale multihop wireless networks. With this algorithm, each and every active link in the network cooperatively calibrates its environment and converges to a desired link schedule for data transmissions within a time frame of multiple slots. This schedule is such that the entire network is partitioned into a set of interleaved subnetworks, where each subnetwork consists of concurrent cochannel links that are properly separated from each other. The desired spacing in each subnetwork can be controlled by a tuning parameter and the number of time slots specified for each frame. Following the DCLS algorithm, a distributed and cooperative power control (DCPC algorithm can be applied to each subnetwork to ensure a desired data rate for each link with minimum network transmission power. As shown consistently by simulations, the DCLS algorithm along with a DCPC algorithm yields significant power savings. The power savings also imply an increased feasible region of averaged link data rates for the entire network.

Distributed and Cooperative Link Scheduling for Large-Scale Multihop Wireless Networks

Directory of Open Access Journals (Sweden)

Ananthram Swami

2007-12-01

Full Text Available A distributed and cooperative link-scheduling (DCLS algorithm is introduced for large-scale multihop wireless networks. With this algorithm, each and every active link in the network cooperatively calibrates its environment and converges to a desired link schedule for data transmissions within a time frame of multiple slots. This schedule is such that the entire network is partitioned into a set of interleaved subnetworks, where each subnetwork consists of concurrent cochannel links that are properly separated from each other. The desired spacing in each subnetwork can be controlled by a tuning parameter and the number of time slots specified for each frame. Following the DCLS algorithm, a distributed and cooperative power control (DCPC algorithm can be applied to each subnetwork to ensure a desired data rate for each link with minimum network transmission power. As shown consistently by simulations, the DCLS algorithm along with a DCPC algorithm yields significant power savings. The power savings also imply an increased feasible region of averaged link data rates for the entire network.

Day-ahead distributed energy resource scheduling using differential search algorithm

DEFF Research Database (Denmark)

Soares, J.; Lobo, C.; Silva, M.

2015-01-01

The number of dispersed energy resources is growing every day, such as the use of more distributed generators. This paper deals with energy resource scheduling model in future smart grids. The methodology can be used by virtual power players (VPPs) considering day-ahead time horizon. This method...... considers that energy resources are managed by a VPP which establishes contracts with their owners. The full AC power flow calculation included in the model takes into account network constraints. This paper presents an application of differential search algorithm (DSA) for solving the day-ahead scheduling...

Analysis of Sleep-Mode Downlink Scheduling Operations in EPON Systems

DEFF Research Database (Denmark)

Yan, Ying; Dittmann, Lars

2011-01-01

Energy management strategy has been considered as an important component in the future Ethernet Passive Optical Networks (EPONs). In this paper, a sleeping mode operation is studied, and a downlink packet scheduling scheme is analyzed to preserve energy consumption and maintain the required Qo......S. This paper proposes a novel sleep-mode downlink packet scheduling scheme in order to enhance the sleep control function. Simulation results confirm that the proposed approach offers effective power management on the basis of the traffic conditions. The trade-off between network performances and the power...

Hydrothermal crystallization of zirconia and zirconia solid solutions

International Nuclear Information System (INIS)

Pyda, W.; Haberko, K.; Bucko, M.M.

1991-01-01

Zirconia as well as yttria-zirconia and calcia-zirconia solid-solution powders were crystallized under hydrothermal conditions from (co)precipitated hydroxides. The morphology of the power particles is strongly dependent on the crystallization conditions. The powders crystallized in a water solution of Na, K, and Li hydroxides show elongated particles of much larger sizes than those which result from the process carried out in pure water or a water solution of Na, K, or Li chlorides. The shapes of the latter particles are isometric. In this paper the growth mechanism of the elongated particles is suggested

Ge/Si Ratios as a Tracer of Hydrothermal Activity in the Nepal Himalaya

Science.gov (United States)

Evans, M. J.; Derry, L. A.

2001-12-01

Advection of deep-seated crustal rocks, high internal heat production, and rapid erosion of the thrust wedge result in steep thermal gradients in the crystalline rocks of the Himalayan front. Meteoric water circulation within these rocks produces geothermal activity in the deeply-incised river valleys near the Main Central Thrust shear zone. The springs have measured temperatures up to 70° C and TDS up to 8000 mg/L and drive significant anomalies in river chemistry. We have carried out a detailed study of the role of hot springs in the Narayani River basin of central Nepal (area 35,000 km2), the major drainage of the central Nepal Himalaya and a major tributary to the Ganges. In order to quantify the fluxes of heat and solutes from geothermal systems in the Narayani basin, the hydrothermal fluid flux must be estimated. As part of an ongoing effort to investigate the use of germanium-silicon systematics, we measured Ge/Si ratios in main stem, tributary and hot spring waters of the Narayani basin. While Ge/Si ratios in tributaries are similar to non-polluted world rivers (Iceland (9 to 150 μ mol/mol). The high Ge/Si ratios in the hot springs may reflect Rayleigh fractionation as low Ge/Si quartz is precipitated. The wide disparity in stream vs. hydrothermal values makes Ge/Si a valuable tool for quantifying hydrothermal fluid flux by mass balance. We can use a hydrothermal fluid flux estimate derived from the chemical mass balance to estimate convective heat loss in the Narayani basin. Preliminary estimates in the Marsyandi River yield a thermal power output rate of 200 MW, comparable with geothermal fields in the Taupo Volcanic Zone and when distributed over the spring affected area, yield a hydrothermal heat flow (160 mW/m2) comparable to continental heat flow and hydrothermal heat loss in the geothermal belt across Tibet. Fluxes of solutes and heat carried by Himalayan hot springs appear to be significant for Himalayan river chemistry and for thermal models of

Car painting process scheduling with harmony search algorithm

Science.gov (United States)

Syahputra, M. F.; Maiyasya, A.; Purnamawati, S.; Abdullah, D.; Albra, W.; Heikal, M.; Abdurrahman, A.; Khaddafi, M.

2018-02-01

Automotive painting program in the process of painting the car body by using robot power, making efficiency in the production system. Production system will be more efficient if pay attention to scheduling of car order which will be done by considering painting body shape of car. Flow shop scheduling is a scheduling model in which the job-job to be processed entirely flows in the same product direction / path. Scheduling problems often arise if there are n jobs to be processed on the machine, which must be specified which must be done first and how to allocate jobs on the machine to obtain a scheduled production process. Harmony Search Algorithm is a metaheuristic optimization algorithm based on music. The algorithm is inspired by observations that lead to music in search of perfect harmony. This musical harmony is in line to find optimal in the optimization process. Based on the tests that have been done, obtained the optimal car sequence with minimum makespan value.

Energy Efficient Real-Time Scheduling Using DPM on Mobile Sensors with a Uniform Multi-Cores

Directory of Open Access Journals (Sweden)

Youngmin Kim

2017-12-01

Full Text Available In wireless sensor networks (WSNs, sensor nodes are deployed for collecting and analyzing data. These nodes use limited energy batteries for easy deployment and low cost. The use of limited energy batteries is closely related to the lifetime of the sensor nodes when using wireless sensor networks. Efficient-energy management is important to extending the lifetime of the sensor nodes. Most effort for improving power efficiency in tiny sensor nodes has focused mainly on reducing the power consumed during data transmission. However, recent emergence of sensor nodes equipped with multi-cores strongly requires attention to be given to the problem of reducing power consumption in multi-cores. In this paper, we propose an energy efficient scheduling method for sensor nodes supporting a uniform multi-cores. We extend the proposed T-Ler plane based scheduling for global optimal scheduling of a uniform multi-cores and multi-processors to enable power management using dynamic power management. In the proposed approach, processor selection for a scheduling and mapping method between the tasks and processors is proposed to efficiently utilize dynamic power management. Experiments show the effectiveness of the proposed approach compared to other existing methods.

Hydrothermal and alkaline hydrothermal pretreatments plus anaerobic digestion of sewage sludge for dewatering and biogas production: Bench-scale research and pilot-scale verification.

Science.gov (United States)

Li, Chunxing; Wang, Xingdong; Zhang, Guangyi; Yu, Guangwei; Lin, Jingjiang; Wang, Yin

2017-06-15

To test the feasibility and practicability of the process combing hydrothermal pretreatment for dewatering with biogas production for full utilization of sewage sludge, hydrothermal/alkaline hydrothermal pretreatments and in turn anaerobic digestion of the filtrates obtained after dewatering the pretreated sludge were performed at bench- and pilot-scales. The hydrothermal temperature fell within the range of 140 °C-220 °C and the pretreatment time varied from 30 min to 120 min. For the alkaline hydrothermal pretreatment the pH value of the sludge was adjusted to 9.0-11.0 by adding Ca(OH) 2 . The results showed that the dewaterability of the sewage sludge was improved with increasing pretreatment temperature but the impact of the pretreatment time was not significant. The addition of Ca(OH) 2 gave better performance on the subsequent mechanical dewatering of the pretreated sludge compared to pure hydrothermal pretreatment, and the higher the pH value was, the better the dewaterability of the pretreated sludge was. The conditions of 180 °C/30 min and 160 °C/60 min/pH = 10.0 (for hydrothermal and alkaline hydrothermal pretreatments, respectively) resulted in relatively good results in the theoretical energy balance, which were verified in the pilot-scale tests. Based on the data from the pilot tests, the alkaline hydrothermal process realized self-sufficiency in energy at the cost of a proper amount of CaO. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Application of Artificial Intelligence to Astronomical Scheduling Problems

Science.gov (United States)

Johnston, Mark D.

1993-01-01

As artificial intelligence (AI) technology has moved from the research laboratory into more and more widespread use, one of the leading applications in astronomy has been to high-profile observation scheduling. The Spike scheduling system was developed by the Space Telescope Science Institute (STScI) for the purpose of long-range scheduling of Hubble Space Telescope (HST). Spike has been in daily operational use at STScI since well before HST launch in April 1990. The system has also been adapted to schedule other missions: one of these missions (EUVE) is currently operational, while another (ASTRO-D) will be launched in February 1993. Some other future space astronomy missions (XTE, SWAS, and AXAF) are making tentative plans to use Spike. Spike has proven to be a powerful and flexible scheduling framework with applicability to a wide variety of problems.

Uplink multi-cluster scheduling with MU-MIMO for LTE-advanced with carrier aggregation

DEFF Research Database (Denmark)

Wang, Hua; Nguyen, Hung Tuan; Rosa, Claudio

2012-01-01

-Advanced requirements and are being considered as part of LTE Release 10. In this paper, some of the physical layer enhancement techniques for LTE-Advanced have been studied including carrier aggregation (CA), uplink multi-cluster scheduling, and uplink multi-user multiple-input multiple-output (MU-MIMO) transmission....... A system-level simulation was conducted to investigate the performance gains that can be achieved in uplink CA with multi-cluster scheduling and MU-MIMO. Simulation results show that with proper separation between power-limited and non-power-limited LTE-A users, multi-cluster scheduling with CA has similar...

Oil drilling rig diesel power-plant fuel efficiency improvement potentials through rule-based generator scheduling and utilization of battery energy storage system

International Nuclear Information System (INIS)

Pavković, Danijel; Sedić, Almir; Guzović, Zvonimir

2016-01-01

Highlights: • Isolated oil drilling rig microgrid power flows are analyzed over 30 days. • Rule-based diesel generator scheduling is proposed to reduce fuel consumption. • A battery energy storage is parameterized and used for peak load leveling. • The effectiveness of proposed hybrid microgrid is verified by simulations. • Return-of-investment might be expected within 20% of battery system lifetime. - Abstract: This paper presents the development of a rule-based energy management control strategy suitable for isolated diesel power-plants equipped with a battery energy storage system for peak load shaving. The proposed control strategy includes the generator scheduling strategy and peak load leveling scheme based on current microgrid active and reactive power requirements. In order to investigate the potentials for fuel expenditure reduction, 30 days-worth of microgrid power flow data has been collected on an isolated land-based oil drilling rig powered by a diesel generator power-plant, characterized by highly-variable active and reactive load profiles due to intermittent engagements and disengagements of high-power electric machinery such as top-drive, draw-works and mud-pump motors. The analysis has indicated that by avoiding the low-power operation of individual generators and by providing the peak power requirements (peak shaving) from a dedicated energy storage system, the power-plant fuel efficiency may be notably improved. An averaged power flow simulation model has been built, comprising the proposed rule-based power flow control strategy and the averaged model of a suitably sized battery energy storage system equipped with grid-tied power converter and state-of-charge control system. The effectiveness of the proposed rule-based strategy has been evaluated by means of computer simulation analysis based on drilling rig microgrid active and reactive power data recorded during the 30 day period. The analysis has indicated that fuel consumption of

Fuzzy generation scheduling for a generation company (GenCo) with large scale wind farms

International Nuclear Information System (INIS)

Siahkali, H.; Vakilian, M.

2010-01-01

Wind power is a promising alternative in power generation because of its tremendous environmental and social benefits. Generation scheduling (GS) is more important in a power system integrating wind farms. Unlike conventional power generation sources, wind power generators supply intermittent power because of uncertainty in resource. This paper presents a fuzzy approach to the generation scheduling problem of a GenCo considering uncertainties in parameters or constraints such as load, reserve and available wind power generation. The modeling of constraints is an important issue in power system scheduling. A fuzzy optimization approach is an approach that can be used to obtain the generation scheduling under an uncertain environment. In this paper, a fuzzy optimization-based method is developed to solve power system GS problem with fuzzy objective and constraints. The crisp formulation of this GS problem is firstly defined and is rearranged by introduction of a membership function of some constraints and objective function. Then, this fuzzy optimization problem is converted to a crisp optimization and solved using GAMS software by mixed integer nonlinear programming. Employing the fuzzy optimization GS, it is expected that in practice a higher profit would be achieved in the operation and cost management of a real power system with large scale wind farms in different level of constraints' satisfaction. The proposed approach is applied to a sample system (including six conventional units and two wind farms) and the results are compared with the results of crisp solution. This approach is also applied to a larger test case to demonstrate the robustness of this fuzzy optimization method.

Combined hydrothermal liquefaction and catalytic hydrothermal gasification system and process for conversion of biomass feedstocks

Science.gov (United States)

Elliott, Douglas C.; Neuenschwander, Gary G.; Hart, Todd R.

2017-09-12

A combined hydrothermal liquefaction (HTL) and catalytic hydrothermal gasification (CHG) system and process are described that convert various biomass-containing sources into separable bio-oils and aqueous effluents that contain residual organics. Bio-oils may be converted to useful bio-based fuels and other chemical feedstocks. Residual organics in HTL aqueous effluents may be gasified and converted into medium-BTU product gases and directly used for process heating or to provide energy.

Hydrothermal decomposition of actinide(IV oxalates: a new aqueous route towards reactive actinide oxide nanocrystals

Directory of Open Access Journals (Sweden)

Walter Olaf

2016-01-01

Full Text Available The hydrothermal decomposition of actinide(IV oxalates (An= Th, U, Pu at temperatures between 95 and 250 °C is shown to lead to the production of highly crystalline, reactive actinide oxide nanocrystals (NCs. This aqueous process proved to be quantitative, reproducible and fast (depending on temperature. The NCs obtained were characterised by X-ray diffraction and TEM showing their size to be smaller than 15 nm. Attempts to extend this general approach towards transition metal or lanthanide oxalates failed in the 95–250 °C temperature range. The hydrothermal decomposition of actinide oxalates is therefore a clean, flexible and powerful approach towards NCs of AnO2 with possible scale-up potential.

Anhydrite precipitation in seafloor hydrothermal systems

Science.gov (United States)

Theissen-Krah, Sonja; Rüpke, Lars H.

2016-04-01

The composition and metal concentration of hydrothermal fluids venting at the seafloor is strongly temperature-dependent and fluids above 300°C are required to transport metals to the seafloor (Hannington et al. 2010). Ore-forming hydrothermal systems and high temperature vents in general are often associated with faults and fracture zones, i.e. zones of enhanced permeabilities that act as channels for the uprising hydrothermal fluid (Heinrich & Candela, 2014). Previous numerical models (Jupp and Schultz, 2000; Andersen et al. 2015) however have shown that high permeabilities tend to decrease fluid flow temperatures due to mixing with cold seawater and the resulting high fluid fluxes that lead to short residence times of the fluid near the heat source. A possible mechanism to reduce the permeability and thereby to focus high temperature fluid flow are mineral precipitation reactions that clog the pore space. Anhydrite for example precipitates from seawater if it is heated to temperatures above ~150°C or due to mixing of seawater with hydrothermal fluids that usually have high Calcium concentrations. We have implemented anhydrite reactions (precipitation and dissolution) in our finite element numerical models of hydrothermal circulation. The initial results show that the precipitation of anhydrite efficiently alters the permeability field, which affects the hydrothermal flow field as well as the resulting vent temperatures. C. Andersen et al. (2015), Fault geometry and permeability contrast control vent temperatures at the Logatchev 1 hydrothermal field, Mid-Atlantic Ridge, Geology, 43(1), 51-54. M. D. Hannington et al. (2010), Modern Sea-Floor Massive Sulfides and Base Metal Resources: Toward an Estimate of Global Sea-Floor Massive Sulfide Potential, in The Challenge of Finding New Mineral Resources: Global Metallogeny, Innovative Exploration, and New Discoveries, edited by R. J. Goldfarb, E. E. Marsh and T. Monecke, pp. 317-338, Society of Economic Geologists

Al-doped SnO2 nanocrystals from hydrothermal systems

International Nuclear Information System (INIS)

Jin Haiying; Xu Yaohua; Pang Guangsheng; Dong Wenjun; Wan Qiang; Sun Yan; Feng Shouhua

2004-01-01

Nanoparticles of Al-doped SnO 2 have been hydrothermally synthesized. The influences of the hydrothermal reaction time, the molar ratio of Sn/Al as well as the pH value of the solution have been studied. During the hydrothermal synthesis, the particle's core is rich in Sn and the surface is rich in Al. The Al-rich surface prevents the particles from further growing up either in the hydrothermal condition or during the calcination at 600 deg. C for a short period of time. The optimal hydrothermal synthesis condition of the nanoparticles is pH 5, Sn/Al=4:1 and 12 h at 160 deg. C. The products have been studied by XRD, TEM and 27 Al solid-state NMR

Non-traditional Stable Isotope Systematics of Seafloor Hydrothermal Systems

Science.gov (United States)

Rouxel, O. J.

2009-05-01

Seafloor hydrothermal activity at mid-ocean ridges is one of the fundamental processes controlling the chemistry of the oceans and the altered oceanic crust. Past studies have demonstrated the complexity and diversity of seafloor hydrothermal systems and have highlighted the importance of subsurface environments in controlling the composition of hydrothermal fluids and mineralization types. Traditionally, the behavior of metals in seafloor hydrothermal systems have been investigated by integrating results from laboratory studies, theoretical models, mineralogy and fluid and mineral chemistry. Isotope ratios of various metals and metalloids, such as Fe, Cu, Zn, Se, Cd and Sb have recently provided new approaches for the study of seafloor hydrothermal systems. Despite these initial investigations, the cause of the isotopic variability of these elements remains poorly constrained. We have little understanding of the isotope variations between vent types (black or white smokers) as well as the influence of source rock composition (basalt, felsic or ultrabasic rocks) and alteration types. Here, I will review and present new results of metal isotope systematics of seafloor hydrothermal systems, in particular: (1) determination of empirical isotope fractionation factors for Zn, Fe and Cu-isotopes through isotopic analysis of mono-mineralic sulfide grains lining the internal chimney wall in contact with hydrothermal fluid; (2) comparison of Fe- and Cu-isotope signatures of vent fluids from mid- oceanic and back-arc hydrothermal fields, spanning wide ranges of pH, temperature, metal concentrations and contributions of magmatic fluids enriched in SO2. Ultimately, the use of complementary non-traditional stable isotope systems may help identify and constrain the complex interactions between fluids,minerals, and organisms in seafloor hydrothermal systems.

Hydrothermal systems and volcano geochemistry

Science.gov (United States)

Fournier, R.O.

2007-01-01

The upward intrusion of magma from deeper to shallower levels beneath volcanoes obviously plays an important role in their surface deformation. This chapter will examine less obvious roles that hydrothermal processes might play in volcanic deformation. Emphasis will be placed on the effect that the transition from brittle to plastic behavior of rocks is likely to have on magma degassing and hydrothermal processes, and on the likely chemical variations in brine and gas compositions that occur as a result of movement of aqueous-rich fluids from plastic into brittle rock at different depths. To a great extent, the model of hydrothermal processes in sub-volcanic systems that is presented here is inferential, based in part on information obtained from deep drilling for geothermal resources, and in part on the study of ore deposits that are thought to have formed in volcanic and shallow plutonic environments.

Ideas and perspectives: hydrothermally driven redistribution and sequestration of early Archaean biomass – the “hydrothermal pump hypothesis”

Directory of Open Access Journals (Sweden)

J.-P. Duda

2018-03-01

Full Text Available Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic. In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga Dresser Formation (Pilbara Craton, Western Australia. Catalytic hydropyrolysis (HyPy of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. This distribution ( ≤  n-C18 is very similar to that observed in HyPy products of recent bacterial biomass, which was used as reference material, whereas it differs markedly from the unimodal distribution of abiotic compounds experimentally formed via Fischer–Tropsch-type synthesis. We therefore propose that the organic matter in the Archaean chert veins has a primarily microbial origin. The microbially derived organic matter accumulated in anoxic aquatic (surface and/or subsurface environments and was then assimilated, redistributed and sequestered by the hydrothermal fluids (hydrothermal pump hypothesis.

An EV Charging Scheduling Mechanism Based on Price Negotiation

Directory of Open Access Journals (Sweden)

Baocheng Wang

2018-05-01

Full Text Available Scheduling EV user’s charging behavior based on charging price and applying renewable energy resources are the effective methods to release the load pressure of power grids brought about by the large-scale popularity of electric vehicles (EVs. This paper presents a novel approach for EV charging scheduling based on price negotiation. Firstly, the EV charging system framework based on price negotiation and renewable energy resources is discussed. Secondly, the price negotiation model is presented, including the initial price models and the conditions of transactions. Finally, an EV charging scheduling mechanism based on price negotiation (CSM-PN, including the price adjustment strategies of both the operator and EV users is proposed to seek a final transaction during multi-round price negotiation. Simulation results show that this novel approach can effectively improve the charging station operator’s income, reduce the EV users’ costs, and balance the load of the power grid while improving the efficiency of the EV charging system.

Modeling of the fault-controlled hydrothermal ore-forming systems

International Nuclear Information System (INIS)

Pek, A.A.; Malkovsky, V.I.

1993-07-01

A necessary precondition for the formation of hydrothermal ore deposits is a strong focusing of hydrothermal flow as fluids move from the fluid source to the site of ore deposition. The spatial distribution of hydrothermal deposits favors the concept that such fluid flow focusing is controlled, for the most part, by regional faults which provide a low resistance path for hydrothermal solutions. Results of electric analog simulations, analytical solutions, and computer simulations of the fluid flow, in a fault-controlled single-pass advective system, confirm this concept. The influence of the fluid flow focusing on the heat and mass transfer in a single-pass advective system was investigated for a simplified version of the metamorphic model for the genesis of greenstone-hosted gold deposits. The spatial distribution of ore mineralization, predicted by computer simulation, is in reasonable agreement with geological observations. Computer simulations of the fault-controlled thermoconvective system revealed a complex pattern of mixing hydrothermal solutions in the model, which also simulates the development of the modern hydrothermal systems on the ocean floor. The specific feature of the model considered, is the development under certain conditions of an intra-fault convective cell that operates essentially independently of the large scale circulation. These and other results obtained during the study indicate that modeling of natural fault-controlled hydrothermal systems is instructive for the analysis of transport processes in man-made hydrothermal systems that could develop in geologic high-level nuclear waste repositories

MANAGING THE LOAD SCHEDULE OF THE ADMINISTRATIVE BUILDING TAKING INTO ACCOUNT EMERGING RISKS WHEN CONNECTING THE KINETIC ENERGY STORAGE TO THE POWER SUPPLY SYSTEM

Directory of Open Access Journals (Sweden)

S. Yu. Shevchenko

2017-12-01

Full Text Available Purpose. The purpose of the paper is to analyze load schedules of the administrative building and develop a structural scheme for connecting the kinetic energy storage in the power supply system of this building, which will allow using it as a consumer regulator, as well as a theoretical study of the risks that arise. Methodology. To conduct the research, the theory of designing internal electrical networks of buildings, the theory of plotting electric load graphs, methods of the theory of electromechanical systems and for analyzing the risk system, the T. Saati method of hierarchies were used. Results. The structure of kinetic energy storage (KES connection to the power supply system of the administrative building is developed and the structural diagram of the KES proposed for installation is given, the average daily winter and summer load schedules are presented, a set of groups and subgroups of risks and their influence on the work of the power supply system of the building are connected with the connection of the KES. Originality. For the first time, the application of the kinetic energy storage in the power supply system of the building with the analysis of emerging risks is considered, which makes it possible to improve the reliability of the developed system and the efficiency of load regulation. Practical value. The application of the proposed scheme will make it possible to use administrative buildings as load regulators of the external power supply system, and also effectively manage the load in the internal power supply system of the building.

Hydrothermal alteration in oceanic ridge volcanics: A detailed study at the Galapagos Fossil Hydrothermal Field

Science.gov (United States)

Ridley, W.I.; Perfit, M.R.; Josnasson, I.R.; Smith, M.F.

1994-01-01

The Galapagos Fossil Hydrothermal Field is composed of altered oceanic crust and extinct hydrothermal vents within the eastern Galapagos Rift between 85??49???W and 85??55???W. The discharge zone of the hydrothermal system is revealed along scarps, thus providing an opportunity to examine the uppermost mineralized, and highly altered interior parts of the crust. Altered rocks collected in situ by the submersible ALVIN show complex concentric alteration zones. Microsamples of individual zones have been analysed for major/minor, trace elements, and strontium isotopes in order to describe the complex compositional details of the hydrothermal alteration. Interlayered chlorite-smectite and chlorite with disequilibrium compositions dominate the secondary mineralogy as replacement phases of primary glass and acicular pyroxene. Phenocrysts and matrix grains of plagioclase are unaffected during alteration. Using a modification of the Gresens' equation we demonstrate that the trivalent rare earth elements (REEs) are relatively immobile, and calculate degrees of enrichment and depletion in other elements. Strontium isotopic ratios increase as Sr concentrations decrease from least-altered cores to most-altered rims and cross-cutting veins in individual samples, and can be modeled by open system behaviour under low fluid-rock ratio (< 10) conditions following a period of lower-temperature weathering of volcanics within the rift zone. The complex patterns of element enrichment and depletion and strontium isotope variations indicate mixing between pristine seawater and ascending hot fluids to produce a compositional spectrum of fluids. The precipitation of base-metal sulfides beneath the seafloor is probably a result of fluid mixing and cooling. If, as suggested here, the discharge zone alteration occurred under relatively low fluid-rock ratios, then this shallow region must play an important role in determining the exit composition of vent fluids in marine hydrothermal systems

Constraint-based job shop scheduling with ILOG SCHEDULER

NARCIS (Netherlands)

Nuijten, W.P.M.; Le Pape, C.

1998-01-01

We introduce constraint-based scheduling and discuss its main principles. An approximation algorithm based on tree search is developed for the job shop scheduling problem using ILOG SCHEDULER. A new way of calculating lower bounds on the makespan of the job shop scheduling problem is presented and

Chemical reaction path modeling of hydrothermal processes on Mars: Preliminary results

Science.gov (United States)

Plumlee, Geoffrey S.; Ridley, W. Ian

1992-01-01

Hydrothermal processes are thought to have had significant roles in the development of surficial mineralogies and morphological features on Mars. For example, a significant proportion of the Martian soil could consist of the erosional products of hydrothermally altered impact melt sheets. In this model, impact-driven, vapor-dominated hydrothermal systems hydrothermally altered the surrounding rocks and transported volatiles such as S and Cl to the surface. Further support for impact-driven hydrothermal alteration on Mars was provided by studies of the Ries crater, Germany, where suevite deposits were extensively altered to montmorillonite clays by inferred low-temperature (100-130 C) hydrothermal fluids. It was also suggested that surface outflow from both impact-driven and volcano-driven hydrothermal systems could generate the valley networks, thereby eliminating the need for an early warm wet climate. We use computer-driven chemical reaction path calculation to model chemical processes which were likely associated with postulated Martian hydrothermal systems.

The chemistry of hydrothermal magnetite: a review

Science.gov (United States)

Nadoll, Patrick; Angerer, Thomas; Mauk, Jeffrey L.; French, David; Walshe, John

2014-01-01

Magnetite (Fe3O4) is a well-recognized petrogenetic indicator and is a common accessory mineral in many ore deposits and their host rocks. Recent years have seen an increased interest in the use of hydrothermal magnetite for provenance studies and as a pathfinder for mineral exploration. A number of studies have investigated how specific formation conditions are reflected in the composition of the respective magnetite. Two fundamental questions underlie these efforts — (i) How can the composition of igneous and, more importantly, hydrothermal magnetite be used to discriminate mineralized areas from barren host rocks, and (ii) how can this assist exploration geologists to target ore deposits at greater and greater distances from the main mineralization? Similar to igneous magnetite, the most important factors that govern compositional variations in hydrothermal magnetite are (A) temperature, (B) fluid composition — element availability, (C) oxygen and sulfur fugacity, (D) silicate and sulfide activity, (E) host rock buffering, (F) re-equilibration processes, and (G) intrinsic crystallographic controls such as ionic radius and charge balance. We discuss how specific formation conditions are reflected in the composition of magnetite and review studies that investigate the chemistry of hydrothermal and igneous magnetite from various mineral deposits and their host rocks. Furthermore, we discuss the redox-related alteration of magnetite (martitization and mushketovitization) and mineral inclusions in magnetite and their effect on chemical analyses. Our database includes published and previously unpublished magnetite minor and trace element data for magnetite from (1) banded iron formations (BIF) and related high-grade iron ore deposits in Western Australia, India, and Brazil, (2) Ag–Pb–Zn veins of the Coeur d'Alene district, United States, (3) porphyry Cu–(Au)–(Mo) deposits and associated (4) calcic and magnesian skarn deposits in the southwestern United

The BGU/CERN solar hydrothermal reactor

CERN Document Server

Bertolucci, Sergio; Caspers, Fritz; Garb, Yaakov; Gross, Amit; Pauletta, Stefano

2014-01-01

We describe a novel solar hydrothermal reactor (SHR) under development by Ben Gurion University (BGU) and the European Organization for Nuclear Research CERN. We describe in broad terms the several novel aspects of the device and, by extension, of the niche it occupies: in particular, enabling direct off-grid conversion of a range of organic feedstocks to sterile useable (solid, liquid) fuels, nutrients, products using only solar energy and water. We then provide a brief description of the high temperature high efficiency panels that provide process heat to the hydrothermal reactor, and review the basics of hydrothermal processes and conversion taking place in this. We conclude with a description of a simulation of the pilot system that will begin operation later this year.

Base hydrolysis and hydrothermal processing of PBX-9404

International Nuclear Information System (INIS)

Flesner, R.L.; Spontarelli, T.; Dell'Orco, P.C.; Sanchez, J.A.

1994-01-01

Base hydrolysis in combination with hydrothermal processing has been proposed as an environmentally acceptable alternative to open burning/open detonation for degradation and destruction of high explosives. In this report, the authors examine gaseous and aqueous products of base hydrolysis of the HMX-based plastic bonded explosive, PBX-9404. They also examined products from the subsequent hydrothermal treatment of the base hydrolysate. The gases produced from hydrolysis of PBX-9404 are ammonia, nitrous oxide, and nitrogen. Major aqueous products are sodium formate, acetate, nitrate, and nitrite, but not all carbon products have been identified. Hydrothermal processing of base hydrolysate destroyed up to 98% of the organic carbon in solution, and higher destruction efficiencies are possible. Major gas products detected from hydrothermal processing were nitrogen and nitrous oxide

Bacterial Diets of Primary Consumers at Hydrothermal Vents

Science.gov (United States)

Govenar, B.; Shank, T. M.

2008-12-01

Chemical energy produced by mixing hydrothermal fluids and seawater supports dense biological communities on mid-ocean ridges. The base of the food web at deep-sea hydrothermal vents is formed by chemolithoautotrophic bacteria that use the energy from the oxidation of reduced chemicals to fix inorganic carbon into simple sugars. With the exception of a few species that have chemolithoautotropic bacterial symbionts, most of the vent-endemic macrofauna are heterotrophs that feed on free-living bacteria, protists, and other invertebrates. The most abundant and diverse group of primary consumers in hydrothermal vent communities belong to the Gastropoda, particularly the patellomorph limpets. Gastropod densities can be as high as 2000 individuals m-2, and there can be as many as 13 species of gastropods in a single aggregation of the siboglinid tubeworm Riftia pachyptila and more than 40 species along the East Pacific Rise. Some gastropods are ubiquitous and others are found in specific microhabitats, stages of succession, or associated with different foundation species. To determine the mechanisms of species coexistence (e.g. resource partitioning or competition) among hydrothermal vent primary consumers and to track the flow of energy in hydrothermal vent communities, we employed molecular genetic techniques to identify the gut contents of four species of co-occurring hydrothermal vent gastropods, Eulepetopsis vitrea, Lepetodrilus elevatus, Lepetodrilus ovalis and Lepetodrilus pustulosus, collected from a single diffuse-flow hydrothermal vent site on the East Pacific Rise. Unique haplotypes of the 16S gene that fell among the epsilon-proteobacteria were found in the guts of every species, and two species had gut contents that were similar only to epsilon-proteobacteria. Two species had gut contents that also included haplotypes that clustered with delta-proteobacteria, and one species had gut contents that clustered with alpha- proteobacteria. Differences in the diets

Organic sulfur metabolisms in hydrothermal environments.

Science.gov (United States)

Rogers, Karyn L; Schulte, Mitchell D

2012-07-01

Sulfur is central to the metabolisms of many organisms that inhabit extreme environments. While biotic and abiotic cycling of organic sulfur compounds has been well documented in low-temperature anaerobic environments, cycling of organic sulfur in hydrothermal environments has received less attention. Recently published thermodynamic data have been used to estimate aqueous alkyl thiol and sulfide activities in deep-sea hydrothermal systems. Here we use geochemical mixing models to predict fluid compositions that result from mixing end-member hydrothermal fluid from the East Pacific Rise with bottom seawater. These fluid compositions are combined with estimates of methanethiol and dimethylsulfide activities to evaluate energy yields for potential organic sulfur-based metabolisms under hydrothermal conditions. Aerobic respiration has the highest energy yields (over -240 kJ/mol e⁻) at lower temperature; however, oxygen is unlikely to persist at high temperatures, restricting aerobic respiration to mesophilic communities. Nitrite reduction to N₂ has the highest energy yields at higher temperatures (greater than ∼40 °C). Nitrate and nitrite reduction to ammonium also yield significant energy (up to -70 kJ/mol e⁻). Much lower, but still feasible energy yields are calculated for sulfate reduction, disproportionation, and reduction with H₂. Organic compound family and the activity of methanethiol and dimethylsulfide were less important than metabolic strategy in determining overall energy yields. All metabolic strategies considered were exergonic within some portion of the mixing regime suggesting that organic sulfur-based metabolisms may be prevalent within deep-sea hydrothermal vent microbial communities. © 2012 Blackwell Publishing Ltd.

Voltammetric Investigation Of Hydrothermal Iron Speciation

Directory of Open Access Journals (Sweden)

Charlotte eKleint

2016-05-01

Full Text Available Hydrothermal vent fluids are highly enriched in iron (Fe compared to ambient seawater, and organic ligands may play a role in facilitating the transport of some hydrothermal Fe into the open ocean. This is important since Fe is a limiting micronutrient for primary production in large parts of the world`s surface ocean. We have investigated the concentration and speciation of Fe in several vent fluid and plume samples from the Nifonea vent field, Coriolis Troughs, New Hebrides Island Arc, South Pacific Ocean using competitive ligand exchange - adsorptive cathodic stripping voltammetry (CLE - AdCSV with salicylaldoxime (SA as the artificial ligand. Our results for total dissolved Fe (dFe in the buoyant hydrothermal plume samples showed concentrations up to 3.86 µM dFe with only a small fraction between 1.1% and 11.8% being chemically labile. Iron binding ligand concentrations ([L] were found in µM level with strong conditional stability constants up to log K[L],Fe3+ of 22.9. Within the non-buoyant hydrothermal plume above the Nifonea vent field, up to 84.7% of the available Fe is chemically labile and [L] concentrations up to 97 nM were measured. [L] was consistently in excess of Felab, indicating that all available Fe is being complexed, which in combination with high Felab values in the non-buoyant plume, signifies that a high fraction of hydrothermal dFe is potentially being transported away from the plume into the surrounding waters, contributing to the global oceanic Fe budget.

Real-time Energy Resource Scheduling considering a Real Portuguese Scenario

DEFF Research Database (Denmark)

Silva, Marco; Sousa, Tiago; Morais, Hugo

2014-01-01

The development in power systems and the introduction of decentralized gen eration and Electric Vehicles (EVs), both connected to distribution networks, represents a major challenge in the planning and operation issues. This new paradigm requires a new energy resources management approach which...... scheduling in smart grids, considering day - ahead, hour - ahead and real - time scheduling. The case study considers a 33 - bus distribution network with high penetration of distributed energy resources . The wind generation profile is base d o n a rea l Portuguese wind farm . Four scenarios are presented...... taking into account 0, 1, 2 and 5 periods (hours or minutes) ahead of the scheduling period in the hour - ahead and real - time scheduling...

Energy-driven scheduling algorithm for nanosatellite energy harvesting maximization

Science.gov (United States)

Slongo, L. K.; Martínez, S. V.; Eiterer, B. V. B.; Pereira, T. G.; Bezerra, E. A.; Paiva, K. V.

2018-06-01

The number of tasks that a satellite may execute in orbit is strongly related to the amount of energy its Electrical Power System (EPS) is able to harvest and to store. The manner the stored energy is distributed within the satellite has also a great impact on the CubeSat's overall efficiency. Most CubeSat's EPS do not prioritize energy constraints in their formulation. Unlike that, this work proposes an innovative energy-driven scheduling algorithm based on energy harvesting maximization policy. The energy harvesting circuit is mathematically modeled and the solar panel I-V curves are presented for different temperature and irradiance levels. Considering the models and simulations, the scheduling algorithm is designed to keep solar panels working close to their maximum power point by triggering tasks in the appropriate form. Tasks execution affects battery voltage, which is coupled to the solar panels through a protection circuit. A software based Perturb and Observe strategy allows defining the tasks to be triggered. The scheduling algorithm is tested in FloripaSat, which is an 1U CubeSat. A test apparatus is proposed to emulate solar irradiance variation, considering the satellite movement around the Earth. Tests have been conducted to show that the scheduling algorithm improves the CubeSat energy harvesting capability by 4.48% in a three orbit experiment and up to 8.46% in a single orbit cycle in comparison with the CubeSat operating without the scheduling algorithm.

Biosphere in 3.5 Ga submarine hydrothermal system

Energy Technology Data Exchange (ETDEWEB)

Ueno, Yuichiro [Tokyo Univ. (Japan). Dept. of Earth Science and Astronomy

2003-04-01

Abundant organic matter (kerogen) was identified in {approx}3.5 Ga hydrothermal silica dikes from the North Pole area in the Pilbara craton, Western Australia. The silica dikes developed in the uppermost 1000 m of the ancient oceanic crust. Thus, they would have been deposited in the 3.5 Ga sub-seafloor hydrothermal system. The carbon and nitrogen isotopic compositions of the kerogen were analyzed in this study. Their highly {sup 13}C-depleted isotopic compositions ({delta}{sup 13}C = -38 to -33 per mille) strongly suggest that they are originally derived from biologically produced organic matter. The remarkable similarity of the {delta}{sup 13}C values between the kerogen and modern hydrothermal vent organisms may suggest that the kerogen was derived from chemoautotrophic organisms. This idea is also consistent with their nitrogen isotopic compositions ({delta}{sup 15}N = -4 to +4 per mille). The silica dikes consist mainly of fine-grained silica with minor pyrite and sphalerite. These mineral assemblages indicate that the silica dike was deposited from relatively low-temperature (probably less than 150degC) reducing hydrothermal fluid. Thus, anaerobic thermophilic/hyperthermophilic organisms could have survived in the hydrothermal fluid, which formed the silica dikes. Therefore, it is plausible that a chemoautotrophic-based biosphere (possibly methanogenesis) probably existed in the Early Archean sub-seafloor hydrothermal system. (author)

Impact of hydrothermalism on the ocean iron cycle.

Science.gov (United States)

Tagliabue, Alessandro; Resing, Joseph

2016-11-28

As the iron supplied from hydrothermalism is ultimately ventilated in the iron-limited Southern Ocean, it plays an important role in the ocean biological carbon pump. We deploy a set of focused sensitivity experiments with a state of the art global model of the ocean to examine the processes that regulate the lifetime of hydrothermal iron and the role of different ridge systems in governing the hydrothermal impact on the Southern Ocean biological carbon pump. Using GEOTRACES section data, we find that stabilization of hydrothermal iron is important in some, but not all regions. The impact on the Southern Ocean biological carbon pump is dominated by poorly explored southern ridge systems, highlighting the need for future exploration in this region. We find inter-basin differences in the isopycnal layer onto which hydrothermal Fe is supplied between the Atlantic and Pacific basins, which when combined with the inter-basin contrasts in oxidation kinetics suggests a muted influence of Atlantic ridges on the Southern Ocean biological carbon pump. Ultimately, we present a range of processes, operating at distinct scales, that must be better constrained to improve our understanding of how hydrothermalism affects the ocean cycling of iron and carbon.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'. © 2016 The Author(s).

rights reserved Geophysical Identification of Hydrothermally Altered ...

African Journals Online (AJOL)

ADOWIE PERE

the pole to the magnetic data aided in mapping of various hydrothermally altered structures that may favour gold mineralisation. The interpretation of the aero data set has enhanced a lot of ... water serves as a concentrating, transporting and depositing agent through faults (structures) to the earth's surface. Hydrothermal ...

Comparison of microbial communities associated with three Atlantic ultramafic hydrothermal systems.

Science.gov (United States)

Roussel, Erwan G; Konn, Cécile; Charlou, Jean-Luc; Donval, Jean-Pierre; Fouquet, Yves; Querellou, Joël; Prieur, Daniel; Bonavita, Marie-Anne Cambon

2011-09-01

The distribution of Archaea and methanogenic, methanotrophic and sulfate-reducing communities in three Atlantic ultramafic-hosted hydrothermal systems (Rainbow, Ashadze, Lost City) was compared using 16S rRNA gene and functional gene (mcrA, pmoA and dsrA) clone libraries. The overall archaeal community was diverse and heterogeneously distributed between the hydrothermal sites and the types of samples analyzed (seawater, hydrothermal fluid, chimney and sediment). The Lost City hydrothermal field, characterized by high alkaline warm fluids (pH>11; Tphylum and Methanopyrales order were also retrieved from the Rainbow and Ashadze hydrothermal fluids. However, the methanogenic Methanococcales was the most widely distributed hyper/thermophilic archaeal group among the hot and acidic ultramafic-hosted hydrothermal system environments. Most of the lineages detected are linked to methane and hydrogen cycling, suggesting that in ultramafic-hosted hydrothermal systems, large methanogenic and methanotrophic communities could be fuelled by hydrothermal fluids highly enriched in methane and hydrogen. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Short-term hydro-thermal-wind complementary scheduling considering uncertainty of wind power using an enhanced multi-objective bee colony optimization algorithm

International Nuclear Information System (INIS)

Zhou, Jianzhong; Lu, Peng; Li, Yuanzheng; Wang, Chao; Yuan, Liu; Mo, Li

2016-01-01

Highlights: • HTWCS system is established while considering uncertainty of wind power. • An enhanced multi-objective bee colony optimization algorithm is proposed. • Some heuristic repairing strategies are designed to handle various constraints. • HTWCS problem with economic/environment objectives is solved by EMOBCO. - Abstract: This paper presents a short-term economic/environmental hydro-thermal-wind complementary scheduling (HTWCS) system considering uncertainty of wind power, as well as various complicated non-linear constraints. HTWCS system is formulated as a multi-objective optimization problem to optimize conflictive objectives, i.e., economic and environmental criteria. Then an enhanced multi-objective bee colony optimization algorithm (EMOBCO) is proposed to solve this problem, which adopts Elite archive set, adaptive mutation/selection mechanism and local searching strategy to improve global searching ability of standard bee colony optimization (BCO). Especially, a novel constraints-repairing strategy with compressing decision space and a violation-adjustment method are used to handle various hydraulic and electric constraints. Finally, a daily scheduling simulation case of hydro-thermal-wind system is conducted to verify feasibility and effectiveness of the proposed EMOBCO in solving HTWCS problem. The simulation results indicate that the proposed EMOBCO can provide lower economic cost and smaller pollutant emission than other method established recently while considering various complex constraints in HTWCS problem.

Hydrothermal processing of actinide contaminated organic wastes

International Nuclear Information System (INIS)

Worl, A.; Buelow, S.J.; Le, L.A.; Padilla, D.D.; Roberts, J.H.

1997-01-01

Hydrothermal oxidation is an innovative process for the destruction of organic wastes, that occurs above the critical temperature and pressure of water. The process provides high destruction and removal efficiencies for a wide variety of organic and hazardous substances. For aqueous/organic mixtures, organic materials, and pure organic liquids hydrothermal processing removes most of the organic and nitrate components (>99.999%) and facilitates the collection and separation of the actinides. We have designed, built and tested a hydrothermal processing unit for the removal of the organic and hazardous substances from actinide contaminated liquids and solids. Here we present results for the organic generated at the Los Alamos National Laboratory Plutonium Facility

Refinery scheduling

Energy Technology Data Exchange (ETDEWEB)

Magalhaes, Marcus V.; Fraga, Eder T. [PETROBRAS, Rio de Janeiro, RJ (Brazil); Shah, Nilay [Imperial College, London (United Kingdom)

2004-07-01

This work addresses the refinery scheduling problem using mathematical programming techniques. The solution adopted was to decompose the entire refinery model into a crude oil scheduling and a product scheduling problem. The envelope for the crude oil scheduling problem is composed of a terminal, a pipeline and the crude area of a refinery, including the crude distillation units. The solution method adopted includes a decomposition technique based on the topology of the system. The envelope for the product scheduling comprises all tanks, process units and products found in a refinery. Once crude scheduling decisions are Also available the product scheduling is solved using a rolling horizon algorithm. All models were tested with real data from PETROBRAS' REFAP refinery, located in Canoas, Southern Brazil. (author)

Hydrothermal processing of inorganic components of Hanford tank sludge

International Nuclear Information System (INIS)

Oldenborg, R.; Buelow, S.J.; Dyer, R.B.; Anderson, G.; Dell'Orco, P.C.; Funk, K.; Wilmanns, E.; Knutsen, K.

1994-09-01

Hydrothermal Processing (HTP) is an attractive approach for the treatment of Hanford tank sludge. Hydrothermal Processing refers to a waste treatment technique in which an aqueous waste stream is fed through a chemical reactor at elevated temperatures and pressures to effect desired chemical transformations and separations. Transformations such as organic and nitrate destruction and sludge reformulation have been demonstrated at pilot scale using simulants of Hanford tank wastes. At sufficiently high temperatures and pressures organics and nitrates are destroyed in seconds, producing primarily simple products such as CO 3 2- , H 2 O, N 2 , N 2 O and OH - , and sludges are reduced in volume and reformulated as rapid settling oxides amenable to downstream separation, or in some cases reformulated as soluble products. This report describes the hydrothermal dissolution of chromium and chromium oxide; the hydrothermal oxidation of chromium with nitrate; hydrothermal dissolution of aluminum-bearing sludges; the solubility of aluminum compounds in caustic hydrothermal media; experimental techniques for the study of solubility and phase behavior; optical cell studies of basic aluminate solution solubilities; and high temperature, low density salt solubility in the packed-bed flow apparatus

Nuclear power. Volume 2: nuclear power project management

International Nuclear Information System (INIS)

Anon.

1980-01-01

The following topics are discussed: review of nuclear power plants; licensing procedures; safety analysis; project professional services; quality assurance and project organization; construction, scheduling and operation; construction, scheduling and operation; nuclear fuel handling and fuel management; and plant cost management. 116 references, 115 figures, 33 tables

Day-Ahead Probabilistic Model for Scheduling the Operation of a Wind Pumped-Storage Hybrid Power Station: Overcoming Forecasting Errors to Ensure Reliability of Supply to the Grid

Directory of Open Access Journals (Sweden)

Jakub Jurasz

2018-06-01

Full Text Available Variable renewable energy sources (VRES, such as solarphotovoltaic (PV and wind turbines (WT, are starting to play a significant role in several energy systems around the globe. To overcome the problem of their non-dispatchable and stochastic nature, several approaches have been proposed so far. This paper describes a novel mathematical model for scheduling the operation of a wind-powered pumped-storage hydroelectricity (PSH hybrid for 25 to 48 h ahead. The model is based on mathematical programming and wind speed forecasts for the next 1 to 24 h, along with predicted upper reservoir occupancy for the 24th hour ahead. The results indicate that by coupling a 2-MW conventional wind turbine with a PSH of energy storing capacity equal to 54 MWh it is possible to significantly reduce the intraday energy generation coefficient of variation from 31% for pure wind turbine to 1.15% for a wind-powered PSH The scheduling errors calculated based on mean absolute percentage error (MAPE are significantly smaller for such a coupling than those seen for wind generation forecasts, at 2.39% and 27%, respectively. This is even stronger emphasized by the fact that, those for wind generation were calculated for forecasts made for the next 1 to 24 h, while those for scheduled generation were calculated for forecasts made for the next 25 to 48 h. The results clearly show that the proposed scheduling approach ensures the high reliability of the WT–PSH energy source.

Hydrothermal influence on nearshore sediments of Kos Island, Aegean Sea

Science.gov (United States)

Megalovasilis, Pavlos; Godelitsas, Athanasios

2015-04-01

The Kos-Nisyros volcanic centre is a long-active, Plio-Pleistocene magmatic system in the subduction zone along the easternmost edge of the active Hellenic volcanic arc in the Aegean Sea. Although today there are signs of relative quiescence in volcanic activity, active onshore fumaroles and shallow-sea hydrothermal vents persist on, amongst others, the island of Kos. The present study explores the large-scale imprint of hydrothermally sourced heavy metals and nutrients on the island's coastal marine environment, based on geochemical data collected in September 2007 from hydrothermal waters and surficial nearshore sediments (Kos is severely influenced by ongoing submarine hydrothermal activity, and confirm that shallow-water sediment Fe, Mn, Zn and Pb levels are substantially higher than those of other islands along the Hellenic volcanic arc, and even exceed those of some deep-water hydrothermal vents in other world regions. Evidently, there may be significant metallic sulphide deposits of hydrothermal origin at depth beneath Kos.

On Multiple Users Scheduling Using Superposition Coding over Rayleigh Fading Channels

KAUST Repository

Zafar, Ammar

2013-02-20

In this letter, numerical results are provided to analyze the gains of multiple users scheduling via superposition coding with successive interference cancellation in comparison with the conventional single user scheduling in Rayleigh blockfading broadcast channels. The information-theoretic optimal power, rate and decoding order allocation for the superposition coding scheme are considered and the corresponding histogram for the optimal number of scheduled users is evaluated. Results show that at optimality there is a high probability that only two or three users are scheduled per channel transmission block. Numerical results for the gains of multiple users scheduling in terms of the long term throughput under hard and proportional fairness as well as for fixed merit weights for the users are also provided. These results show that the performance gain of multiple users scheduling over single user scheduling increases when the total number of users in the network increases, and it can exceed 10% for high number of users

Two-Stage Multi-Objective Collaborative Scheduling for Wind Farm and Battery Switch Station

Directory of Open Access Journals (Sweden)

Zhe Jiang

2016-10-01

Full Text Available In order to deal with the uncertainties of wind power, wind farm and electric vehicle (EV battery switch station (BSS were proposed to work together as an integrated system. In this paper, the collaborative scheduling problems of such a system were studied. Considering the features of the integrated system, three indices, which include battery swapping demand curtailment of BSS, wind curtailment of wind farm, and generation schedule tracking of the integrated system are proposed. In addition, a two-stage multi-objective collaborative scheduling model was designed. In the first stage, a day-ahead model was built based on the theory of dependent chance programming. With the aim of maximizing the realization probabilities of these three operating indices, random fluctuations of wind power and battery switch demand were taken into account simultaneously. In order to explore the capability of BSS as reserve, the readjustment process of the BSS within each hour was considered in this stage. In addition, the stored energy rather than the charging/discharging power of BSS during each period was optimized, which will provide basis for hour-ahead further correction of BSS. In the second stage, an hour-ahead model was established. In order to cope with the randomness of wind power and battery swapping demand, the proposed hour-ahead model utilized ultra-short term prediction of the wind power and the battery switch demand to schedule the charging/discharging power of BSS in a rolling manner. Finally, the effectiveness of the proposed models was validated by case studies. The simulation results indicated that the proposed model could realize complement between wind farm and BSS, reduce the dependence on power grid, and facilitate the accommodation of wind power.

Spontaneous and Widespread Electricity Generation in Natural Deep-Sea Hydrothermal Fields.

Science.gov (United States)

Yamamoto, Masahiro; Nakamura, Ryuhei; Kasaya, Takafumi; Kumagai, Hidenori; Suzuki, Katsuhiko; Takai, Ken

2017-05-15

Deep-sea hydrothermal vents discharge abundant reductive energy into oxidative seawater. Herein, we demonstrated that in situ measurements of redox potentials on the surfaces of active hydrothermal mineral deposits were more negative than the surrounding seawater potential, driving electrical current generation. We also demonstrated that negative potentials in the surface of minerals were widespread in the hydrothermal fields, regardless of the proximity to hydrothermal fluid discharges. Lab experiments verified that the negative potential of the mineral surface was induced by a distant electron transfer from the hydrothermal fluid through the metallic and catalytic properties of minerals. These results indicate that electric current is spontaneously and widely generated in natural mineral deposits in deep-sea hydrothermal fields. Our discovery provides important insights into the microbial communities that are supported by extracellular electron transfer and the prebiotic chemical and metabolic evolution of the ocean hydrothermal systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrothermal systems in small ocean planets.

Science.gov (United States)

Vance, Steve; Harnmeijer, Jelte; Kimura, Jun; Hussmann, Hauke; Demartin, Brian; Brown, J Michael

2007-12-01

We examine means for driving hydrothermal activity in extraterrestrial oceans on planets and satellites of less than one Earth mass, with implications for sustaining a low level of biological activity over geological timescales. Assuming ocean planets have olivine-dominated lithospheres, a model for cooling-induced thermal cracking shows how variation in planet size and internal thermal energy may drive variation in the dominant type of hydrothermal system-for example, high or low temperature system or chemically driven system. As radiogenic heating diminishes over time, progressive exposure of new rock continues to the current epoch. Where fluid-rock interactions propagate slowly into a deep brittle layer, thermal energy from serpentinization may be the primary cause of hydrothermal activity in small ocean planets. We show that the time-varying hydrostatic head of a tidally forced ice shell may drive hydrothermal fluid flow through the seafloor, which can generate moderate but potentially important heat through viscous interaction with the matrix of porous seafloor rock. Considering all presently known potential ocean planets-Mars, a number of icy satellites, Pluto, and other trans-neptunian objects-and applying Earth-like material properties and cooling rates, we find depths of circulation are more than an order of magnitude greater than in Earth. In Europa and Enceladus, tidal flexing may drive hydrothermal circulation and, in Europa, may generate heat on the same order as present-day radiogenic heat flux at Earth's surface. In all objects, progressive serpentinization generates heat on a globally averaged basis at a fraction of a percent of present-day radiogenic heating and hydrogen is produced at rates between 10(9) and 10(10) molecules cm(2) s(1).

Coupling hydrothermal liquefaction and anaerobic digestion for energy valorization from model biomass feedstocks.

Science.gov (United States)

Posmanik, Roy; Labatut, Rodrigo A; Kim, Andrew H; Usack, Joseph G; Tester, Jefferson W; Angenent, Largus T

2017-06-01

Hydrothermal liquefaction converts food waste into oil and a carbon-rich hydrothermal aqueous phase. The hydrothermal aqueous phase may be converted to biomethane via anaerobic digestion. Here, the feasibility of coupling hydrothermal liquefaction and anaerobic digestion for the conversion of food waste into energy products was examined. A mixture of polysaccharides, proteins, and lipids, representing food waste, underwent hydrothermal processing at temperatures ranging from 200 to 350°C. The anaerobic biodegradability of the hydrothermal aqueous phase was examined through conducting biochemical methane potential assays. The results demonstrate that the anaerobic biodegradability of the hydrothermal aqueous phase was lower when the temperature of hydrothermal processing increased. The chemical composition of the hydrothermal aqueous phase affected the anaerobic biodegradability. However, no inhibition of biodegradation was observed for most samples. Combining hydrothermal and anaerobic digestion may, therefore, yield a higher energetic return by converting the feedstock into oil and biomethane. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modeling the individual plants for the planning of the energetic operation of the national interconnected power system; Uma modelagem a usinas individualizadas para o planejamento da operacao energetica do sistema interligado nacional

Energy Technology Data Exchange (ETDEWEB)

Marques, T.C.; Cruz Junior, G.; Vinhal, C. [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Escola de Engenharia Eletrica e de Computacao], Emails: thyago@eeec.ufg.br, gcruz@eeec.ufg.br, vinhal@eeec.ufg.br

2009-07-01

This paper presents an operational policy for the mid term hydrothermal scheduling of the Brazilian Interconnected Power System (BIPS) based on the individual representation of the hydro and thermo power plants, the detailed representation of the plants' features and the indirect representation of the inflow stochasticity through a forecasting model. These characteristics differs the operational policy which is in use nowadays in BIPS, which is based on four interconnected subsystems represented by composite reservoirs. Several case studies are presented to evaluate the performance of the operational policy, from the simple case with a single hydro plant system to the complete case of the whole BIPS under real conditions. For this last case an operational adjustment procedure was implemented to assure the market attendance considering interchange constraints between the subsystems. (author)

Large-scale in situ heater tests for hydrothermal characterization at Yucca Mountain

International Nuclear Information System (INIS)

Buscheck, T.A.; Wilder, D.G.; Nitao, J.J.

1993-01-01

To safely and permanently store high-level nuclear waste, the potential Yucca Mountain repository site must mitigate the release and transport of radionuclides for tens of thousands of years. In the failure scenario of greatest concern, water would contact a waste package, accelerate its failure rate, and eventually transport radionuclides to the water table. Our analyses indicate that the ambient hydrological system will be dominated by repository-heat-driven hydrothermal flow for tens of thousands of years. In situ heater tests are required to provide an understanding of coupled geomechanical-hydrothermal-geochemical behavior in the engineered and natural barriers under repository thermal loading conditions. In situ heater tests have been included in the Site Characterization Plan in response to regulatory requirements for site characterization and to support the validation of process models required to assess the total systems performance at the site. Because of limited time, some of the in situ tests will have to be accelerated relative to actual thermal loading conditions. We examine the trade-offs between the limited test duration and generating hydrothermal conditions applicable to repository performance during the entire thermal loading cycle, including heating (boiling and dry-out) and cooldown (re-wetting). For in situ heater tests to be applicable to actual repository conditions, a minimum heater test duration of 6-7 yr (including 4 yr of full-power heating) is required

Hydrothermal processing of radioactive combustible waste

International Nuclear Information System (INIS)

Worl, L.A.; Buelow, S.J.; Harradine, D.; Le, L.; Padilla, D.D.; Roberts, J.H.

1998-01-01

Hydrothermal processing has been demonstrated for the treatment of radioactive combustible materials for the US Department of Energy. A hydrothermal processing system was designed, built and tested for operation in a plutonium glovebox. Presented here are results from the study of the hydrothermal oxidation of plutonium and americium contaminated organic wastes. Experiments show the destruction of the organic component to CO 2 and H 2 O, with 30 wt.% H 2 O 2 as an oxidant, at 540 C and 46.2 MPa. The majority of the actinide component forms insoluble products that are easily separated by filtration. A titanium liner in the reactor and heat exchanger provide corrosion resistance for the oxidation of chlorinated organics. The treatment of solid material is accomplished by particle size reduction and the addition of a viscosity enhancing agent to generate a homogeneous pumpable mixture

Hydrothermal Liquefaction of Biomass

Energy Technology Data Exchange (ETDEWEB)

Elliott, Douglas C.

2010-12-10

Hydrothermal liquefaction technology is describes in its relationship to fast pyrolysis of biomass. The scope of work at PNNL is discussed and some intial results are presented. HydroThermal Liquefaction (HTL), called high-pressure liquefaction in earlier years, is an alternative process for conversion of biomass into liquid products. Some experts consider it to be pyrolysis in solvent phase. It is typically performed at about 350 C and 200 atm pressure such that the water carrier for biomass slurry is maintained in a liquid phase, i.e. below super-critical conditions. In some applications catalysts and/or reducing gases have been added to the system with the expectation of producing higher yields of higher quality products. Slurry agents ('carriers') evaluated have included water, various hydrocarbon oils and recycled bio-oil. High-pressure pumping of biomass slurry has been a major limitation in the process development. Process research in this field faded away in the 1990s except for the HydroThermal Upgrading (HTU) effort in the Netherlands, but has new resurgence with other renewable fuels in light of the increased oil prices and climate change concerns. Research restarted at Pacific Northwest National Laboratory (PNNL) in 2007 with a project, 'HydroThermal Liquefaction of Agricultural and Biorefinery Residues' with partners Archer-Daniels-Midland Company and ConocoPhillips. Through bench-scale experimentation in a continuous-flow system this project investigated the bio-oil yield and quality that could be achieved from a range of biomass feedstocks and derivatives. The project was completed earlier this year with the issuance of the final report. HydroThermal Liquefaction research continues within the National Advanced Biofuels Consortium with the effort focused at PNNL. The bench-scale reactor is being used for conversion of lignocellulosic biomass including pine forest residue and corn stover. A complementary project is an international

Treatment of urban sludge by hydrothermal carbonization.

Science.gov (United States)

Xu, Xiwei; Jiang, Enchen

2017-08-01

Urban sludge was treated by Hydrothermal carbonization (HTC). The effect of hydrothermal carbonization temperature, mixing with or without catalysts on solid products yield, heavy metal contents, turbidity and COD value was evaluated. The result showed solid products yield decreased from 92.04% to 52.65% when the temperature increased from 180 to 300°C. And the Cu, Zn, and Pb contents under exchangeable states decreased and reached discharge standard. Addition of FeCl 3 or Al(OH) 3 resulted in a significant increase in the exchangeable states of Zn, Pb, Cr, and Cd and decrease in their residual states. The turbidity and COD value of hydrothermal liquid decreased from 450° to 175°, and 13 to 6.8g/L, with increasing hydrothermal temperature. Comparison with HTC, solid productivity from low-temperature pyrolysis is higher. The exchangeable states of Cu, Zn, and Cr exceeded the limiting values. Our results show HTC can facilitate transforming urban sludge into no-pollution and energy-rich products. Copyright © 2017 Elsevier Ltd. All rights reserved.

A derived heuristics based multi-objective optimization procedure for micro-grid scheduling

Science.gov (United States)

Li, Xin; Deb, Kalyanmoy; Fang, Yanjun

2017-06-01

With the availability of different types of power generators to be used in an electric micro-grid system, their operation scheduling as the load demand changes with time becomes an important task. Besides satisfying load balance constraints and the generator's rated power, several other practicalities, such as limited availability of grid power and restricted ramping of power output from generators, must all be considered during the operation scheduling process, which makes it difficult to decide whether the optimization results are accurate and satisfactory. In solving such complex practical problems, heuristics-based customized optimization algorithms are suggested. However, due to nonlinear and complex interactions of variables, it is difficult to come up with heuristics in such problems off-hand. In this article, a two-step strategy is proposed in which the first task deciphers important heuristics about the problem and the second task utilizes the derived heuristics to solve the original problem in a computationally fast manner. Specifically, the specific operation scheduling is considered from a two-objective (cost and emission) point of view. The first task develops basic and advanced level knowledge bases offline from a series of prior demand-wise optimization runs and then the second task utilizes them to modify optimized solutions in an application scenario. Results on island and grid connected modes and several pragmatic formulations of the micro-grid operation scheduling problem clearly indicate the merit of the proposed two-step procedure.

Large-scale Wind Power integration in a Hydro-Thermal Power Market

OpenAIRE

Trøtscher, Thomas

2007-01-01

This master thesis describes a quadratic programming model used to calculate the spot prices in an efficient multi-area power market. The model has been adapted to Northern Europe, with focus on Denmark West and the integration of large quantities of wind power. In the model, demand and supply of electricity are equated, at an hourly time resolution, to find the spot price in each area. Historical load values are used to represent demand which is assumed to be completely inelastic. Supply i...

Distributed Hybrid Scheduling in Multi-Cloud Networks using Conflict Graphs

KAUST Repository

Douik, Ahmed

2017-09-07

Recent studies on cloud-radio access networks assume either signal-level or scheduling-level coordination. This paper considers a hybrid coordinated scheme as a means to benefit from both policies. Consider the downlink of a multi-cloud radio access network, where each cloud is connected to several base-stations (BSs) via high capacity links, and, therefore, allows for joint signal processing within the cloud transmission. Across the multiple clouds, however, only scheduling-level coordination is permitted, as low levels of backhaul communication are feasible. The frame structure of every BS is composed of various time/frequency blocks, called power-zones (PZs), which are maintained at a fixed power level. The paper addresses the problem of maximizing a network-wide utility by associating users to clouds and scheduling them to the PZs, under the practical constraints that each user is scheduled to a single cloud at most, but possibly to many BSs within the cloud, and can be served by one or more distinct PZs within the BSs’ frame. The paper solves the problem using graph theory techniques by constructing the conflict graph. The considered scheduling problem is, then, shown to be equivalent to a maximum-weight independent set problem in the constructed graph, which can be solved using efficient techniques. The paper then proposes solving the problem using both optimal and heuristic algorithms that can be implemented in a distributed fashion across the network. The proposed distributed algorithms rely on the well-chosen structure of the constructed conflict graph utilized to solve the maximum-weight independent set problem. Simulation results suggest that the proposed optimal and heuristic hybrid scheduling strategies provide appreciable gain as compared to the scheduling-level coordinated networks, with a negligible degradation to signal-level coordination.

Water column imaging on hydrothermal vent in Central Indian Ridge

Science.gov (United States)

Koh, J.; Park, Y.

2017-12-01

Water column imaging with Multibeam echosounder systems (MBES) is recently becoming of increasing interest for oceanographic studies. Especially gas bubbles and hot water exposed from hydrothermal vents make acoustic impedance anomalies in cold seawater, water column imaging is very useful for the researchers who want to detect some kinds of hydrothermal activity. We conducted a hydrothermal exploration program, called "INVENT17", using the MBES system, KONGBERG EM122 (12kHz, 1°×1°), mounted on R/V ISABU and we deployed other equipments including video guided hydraulic grab, tow-yo CTD and general CTD with MAPR (Miniature Autonomous Plume Recorder) in 2017. First, to evaluate its capabilities of detection of hydrothermal vent, the surveys using the MBES were conducted at the Solitaire Field, previously identified hydrothermal area of the Central Indian Ridge. The bathymetric data obtained from MBES provided information about detailed morphology of seafloor, but we were not able to achieve the information from the water column imaging data. But the clue of existence of active hydrothermal vent was detected through the values of ΔNTU, dEh/dt, and OPR gained from MAPR, the data means that the hydrothermal activity affects 100m from the seafloor. It could be the reason that we can't find the hydrothermal activity because the range resolution of water column imaging is pretty rough so that the size of 100m-scaled activity has low possibility to distinguish from seafloor. The other reason is there are no sufficient objects to cause strong scattering like as CO2 bubbles or droplets unlike in the mid-Okinawa Trough. And this suggests that can be a important standard to identify properties of hydrothermal vent sites depending on the presence of scattering objects in water mass. To justify this, we should perform more chemical analysis of hot water emanating from hydrothermal vent and collected several bottles of water sample to do that.

Hydrothermal Carbonization of Seaweed For Advanced Biochar Production

Directory of Open Access Journals (Sweden)

Prakoso Tirto

2018-01-01

Full Text Available Seaweed such as Eucheuma Cottonii is a potential source of biomaterialIts high moisture content makes it suitable for hydrothermal conversion process since it doesn’t need to utilize dry feedstock. The aim of this study is to convert the biomass of red seaweed Eucheuma Cottonii into alternative fuels and high value biomaterials using hydrothermal process. The hydrothermal process seaweed Eucheuma Cottonii produce two types of products, liquid product and char (solid. This research focus on the char product. The char from hydrothermal process was then activated using the tubular furnace. The yield for activated char is 7.5 % and results of SEM analysis of activated char showed the formation of allotropes carbon include carbon micro spheres, carbon micro fibres and graphene. These structures have encountered application in a wide range of technological fields, such as adsorption, catalysis, hydrogen storage or electronics.

Solidification of glass powder by a hydrothermal hot-pressing technique

International Nuclear Information System (INIS)

Nishioka, Mamoru; Yanagisawa, Kazumichi; Yamasaki, Nakamichi

1986-01-01

A borosilicate glass powder was solidified with a NaOH solution or distilled water by the hydrothermal hot-pressing technique. The effect of hydrothermal conditions on the compressive strength was investigated, and the densification mechanism of the glass powder during the hydrothermal hot-pressing was discussed in terms of isothermal shrinkage. The glass powder was successfully solidified by hydrothermal hot-pressing at a reaction temperature lower than that of an ordinary pressure sintering. The solidified body obtained in the presence of distilled water (10 wt%) at 280 deg C had a high compressive strength of about 2300 kg/cm 2 . The analysis of initial densification process of the glass powder in hydrothermal hot-pressing with Murray's rate equation revealed that the densification proceeds both by viscous flow and by rearrangement process. Analysis of the shrinkage rates with a rate equation of hydrothermal reaction suggested that the dissolution of particles into solution controlled the initial densification of the glass powder, and that the alkaline metal acted as a catalyst. (author)

Effect of hydrothermal treatment of coal on its associative structure

Energy Technology Data Exchange (ETDEWEB)

Shui Heng-fu; Wang Zhi-cai; Wang Gao-qiang; Niu Min-feng [Anhui University of Technology, Maanshan (China). School of Chemistry & Chemical Engineering

2006-10-15

4 bituminous coals with different ranks were thermally and hydrothermally treated under different conditions, and the raw and treated coals were extracted with carbon disulfide/N-2-pyrrolidinone (CS{sub 2}/NMP) mixed solvent (1:1 by volume). It is found that the extraction yields of the thermal or hydrothermal treated coals at proper conditions increase in different extent. The increments of extraction yields for hydrothermal treated coals are higher than those of thermal treated coals. FT-IR shows that the adsorption peaks at 3410 cm{sup -1} attributed to OH group for the hydrothermal treated coals decrease, suggesting the dissociation of the coal aggregation structure due to the breakage of hydrogen bonds, resulting in the increase of extraction yields for the treated coals. For higher rank coal, the removal of minerals and the dissociation of {pi}-cation association after hydrothermal treatment of coal may be responsible for the increase of extraction yield. In addition, the mechanism of hydrothermal treatment of coal was discussed. 15 refs., 2 figs., 5 tabs.

Hydrothermal industrialization: direct heat development. Final report

Energy Technology Data Exchange (ETDEWEB)

1982-05-01

A description of hydrothermal resources suitable for direct applications, their associated temperatures, geographic distribution and developable capacity are given. An overview of the hydrothermal direct-heat development infrastructure is presented. Development activity is highlighted by examining known and planned geothermal direct-use applications. Underlying assumptions and results for three studies conducted to determine direct-use market penetration of geothermal energy are discussed.

Microwave-assisted hydrothermal synthesis of lead zirconate fine powders

Directory of Open Access Journals (Sweden)

Apinpus Rujiwatra

2011-01-01

Full Text Available A rapid synthesis of lead zirconate fine powders by microwave-assisted hydrothermal technique is reported. The influences of type of lead precursor, concentration of potassium hydroxide mineraliser, applied microwave power and irradiation time are described. The synthesised powders were characterised by powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopic microanalysis and light scattering technique. The merits of the microwave application in reducing reaction time and improving particle mono-dispersion and size uniformity as well as the drawbacks, viz. low purity of the desired phase and increasing demand of mineraliser, are discussed in relation to conventional heating method.

EFFECTS OF HEAT-FLOW AND HYDROTHERMAL FLUIDS FROM ...

African Journals Online (AJOL)

Volcanic intrusions and hydrothermal activity have modified the diagenetic minerals. In the Ulster Basin, UK, most of the authigenic mineralization in the Permo-Triassic sandstones pre-dated tertiary volcanic intrusions. The hydrothermal fluids and heat-flow from the volcanic intrusions did not affect quartz and feldspar ...

Mineralogy and geological significance of hydrothermal deposits from the Okinawa Trough

Science.gov (United States)

Zhang, Xia; Zhai, Shikui; Yu, Zenghui; Wang, Shujie; Cai, Zongwei

2018-04-01

The study of hydrothermal deposits in the Okinawa Trough can help us to uncover the hydrothermal mineralization characteristics in the back-arc basin during the early expanding stage. Mineralogy and geological significance of hydrothermal deposits from both the middle and southern trough are studied in this paper. First of all, using optical microscope to confirm the mineral compositions, characteristics of crystal shape, paragenetic relationship and minerals crystallization order. Then the minerals chemical composition were analyzed in virtue of electron microprobe. On these basis, the paragenetic sequence and the mineralization characteristics of the hydrothermal deposits were discussed. The results show that the hydrothermal deposit from the mid-Okinawa Trough belongs to Zn-Cu-rich type, consisting dominantly of sulfide minerals such as sphalerite, chalcopyrite, pyrite, etc. The minerals crystallization order is first generation pyrite(PyI)-sphalerite-chalcopyrite-galena-second generation pyrite(PyII)-amorphous silica. While the deposit from the southern Okinawa Trough is Ba-Zn-Pb-rich type mainly composing of barite, sphalerite, galena, etc. The minerals crystallization order is barite-pyrite-sphalerite-tetrahedrite-galena-chalcopyrite-amorphous silica. Hydrothermal fluid temperature in the mid-Okinawa Trough undergoes a process from high to low, which is high up to 350 °C in the early stage, but decreasing gradually with the evolution of hydrothermal fluid. On the contrary, the hydrothermal activity in the southern Okinawa Trough is low temperature dominated, but the mineralization environment is unstable and the fluid temperature changes drastically during the period of hydrothermal activity.

System-level power optimization for real-time distributed embedded systems

Science.gov (United States)

Luo, Jiong

Power optimization is one of the crucial design considerations for modern electronic systems. In this thesis, we present several system-level power optimization techniques for real-time distributed embedded systems, based on dynamic voltage scaling, dynamic power management, and management of peak power and variance of the power profile. Dynamic voltage scaling has been widely acknowledged as an important and powerful technique to trade off dynamic power consumption and delay. Efficient dynamic voltage scaling requires effective variable-voltage scheduling mechanisms that can adjust voltages and clock frequencies adaptively based on workloads and timing constraints. For this purpose, we propose static variable-voltage scheduling algorithms utilizing criticalpath driven timing analysis for the case when tasks are assumed to have uniform switching activities, as well as energy-gradient driven slack allocation for a more general scenario. The proposed techniques can achieve closeto-optimal power savings with very low computational complexity, without violating any real-time constraints. We also present algorithms for power-efficient joint scheduling of multi-rate periodic task graphs along with soft aperiodic tasks. The power issue is addressed through both dynamic voltage scaling and power management. Periodic task graphs are scheduled statically. Flexibility is introduced into the static schedule to allow the on-line scheduler to make local changes to PE schedules through resource reclaiming and slack stealing, without interfering with the validity of the global schedule. We provide a unified framework in which the response times of aperiodic tasks and power consumption are dynamically optimized simultaneously. Interconnection network fabrics point to a new generation of power-efficient and scalable interconnection architectures for distributed embedded systems. As the system bandwidth continues to increase, interconnection networks become power/energy limited as

Analysis of Sleep-Mode Downlink Scheduling Operations in EPON Systems

OpenAIRE

Yan, Ying; Dittmann, Lars

2011-01-01

Energy management strategy has been considered as an important component in the future Ethernet Passive Optical Networks (EPONs). In this paper, a sleeping mode operation is studied, and a downlink packet scheduling scheme is analyzed to preserve energy consumption and maintain the required QoS. This paper proposes a novel sleep-mode downlink packet scheduling scheme in order to enhance the sleep control function. Simulation results confirm that the proposed approach offers effective power ma...

Hydrothermal liquefaction of biomass

DEFF Research Database (Denmark)

Toor, Saqib; Rosendahl, Lasse; Hoffmann, Jessica

2014-01-01

Biomass is one of the most abundant sources of renewable energy, and will be an important part of a more sustainable future energy system. In addition to direct combustion, there is growing attention on conversion of biomass into liquid en-ergy carriers. These conversion methods are divided...... into biochemical/biotechnical methods and thermochemical methods; such as direct combustion, pyrolysis, gasification, liquefaction etc. This chapter will focus on hydrothermal liquefaction, where high pressures and intermediate temperatures together with the presence of water are used to convert biomass...... into liquid biofuels, with the aim of describing the current status and development challenges of the technology. During the hydrothermal liquefaction process, the biomass macromolecules are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive...

Optimal joint scheduling of electrical and thermal appliances in a smart home environment

International Nuclear Information System (INIS)

Shirazi, Elham; Zakariazadeh, Alireza; Jadid, Shahram

2015-01-01

Highlights: • Thermal appliances are scheduled based on desired temperature and energy prices. • A discomfort index has been introduced within the home energy scheduling model. • Appliances are scheduled based on activity probability and desired options. • Starting probability depends on the social random factor and consumption behavior. - Abstract: With the development of home area network, residents have the opportunity to schedule their power usage in the home by themselves aiming at reducing electricity expenses. Moreover, as renewable energy sources are deployed in home, a home energy management system needs to consider both energy consumption and generation simultaneously to minimize the energy cost. In this paper, a smart home energy management model has been presented in which electrical and thermal appliances are jointly scheduled. The proposed method aims at minimizing the electricity cost of a residential customer by scheduling various type of appliances considering the residents consumption behavior, seasonal probability, social random factor, discomfort index and appliances starting probability functions. In this model, the home central controller receives the electricity price information, environmental factors data as well as the resident desired options in order to optimally schedule appliances including electrical and thermal. The scheduling approach is tested on a typical home including variety of home appliances, a small wind turbine, photovoltaic panel, combined heat and power unit, boiler and electrical and thermal storages over a 24-h period. The results show that the scheduling of different appliances can be reached simultaneously by using the proposed formulation. Moreover, simulation results evidenced that the proposed home energy management model exhibits a lower cost and, therefore, is more economical.

The hydrothermal evolution of the Kawerau geothermal system, New Zealand

Science.gov (United States)

Milicich, S. D.; Chambefort, I.; Wilson, C. J. N.; Charlier, B. L. A.; Tepley, F. J.

2018-03-01

Hydrothermal alteration zoning and processes provide insights into the evolution of heat source(s) and fluid compositions associated with geothermal systems. Traditional petrological techniques, combined with hydrothermal alteration studies, stable isotope analyses and geochronology can resolve the nature of the fluids involved in hydrothermal processes and their changes through time. We report here new findings along with previous unpublished works on alteration patterns, fluid inclusion measurements and stable isotope data to provide insights into the thermal and chemical evolution of the Kawerau geothermal system, New Zealand. These data indicate the presence of two hydrothermal events that can be coupled with chronological data. The earlier period of hydrothermal activity was initiated at 400 ka, with the heat driving the hydrothermal system inferred to be from the magmatic system that gave rise to rhyolite lavas and sills of the Caxton Formation. Isotopic data fingerprint fluids attributed to this event as meteoric, indicating that the magma primarily served as a heat source driving fluid circulation, and was not releasing magmatic fluids in sufficient quantity to affect the rock mineralogy and thus inferred fluid compositions. The modern Kawerau system was initiated at 16 ka with hydrothermal eruptions linked to shallow intrusion of magma at the onset of activity that gave rise to the Putauaki andesite cone. Likely associated with this later event was a pulse of magmatic CO2, resulting in large-scale deposition of hydrothermal calcite enriched in 18O. Meteoric water-dominated fluids subsequently overwhelmed the magmatic fluids associated with this 18O-rich signature, and both the fluid inclusion microthermometry and stable isotope data reflect a change to the present-day fluid chemistry of low salinity, meteoric-dominated waters.

Joint Scheduling for Dual-Hop Block-Fading Broadcast Channels

KAUST Repository

Zafar, Ammar

2012-09-16

In this paper, we propose joint user-and-hop scheduling over dual-hop block-fading broadcast channels in order to exploit multi-user diversity gains and multi-hop diversity gains all together. To achieve this objective, the first and second hops are scheduled opportunistically based on the channel state information and as a prerequisite we assume that the relay, which is half-duplex and operates using decode-and-forward, is capable of storing the received packets from the source until the channel condition of the destined user becomes good to be scheduled. We formulate the joint scheduling problem as maximizing the weighted sum of the long term achievable rates by the users under a stability constraint, which means that on the long term the rate received by the relay should equal the rate transmitted by it, in addition to constant or variable power constraints. We show that this problem is equivalent to a single-hop broadcast channel by treating the source as a virtual user with an optimal priority weight that maintains the stability constraint. We show how to obtain the source weight either off-line based on channel statistics or on real-time based on channel measurements. Furthermore, we consider special cases including the maximum sum rate scheduler and the proportional fair scheduler. We demonstrate via numerical results that our proposed joint scheduling scheme enlarges the rate region as compared with a scheme that employs multi-user scheduling alone.

Ensuring the Reliable Operation of the Power Grid: State-Based and Distributed Approaches to Scheduling Energy and Contingency Reserves

Science.gov (United States)

Prada, Jose Fernando

Keeping a contingency reserve in power systems is necessary to preserve the security of real-time operations. This work studies two different approaches to the optimal allocation of energy and reserves in the day-ahead generation scheduling process. Part I presents a stochastic security-constrained unit commitment model to co-optimize energy and the locational reserves required to respond to a set of uncertain generation contingencies, using a novel state-based formulation. The model is applied in an offer-based electricity market to allocate contingency reserves throughout the power grid, in order to comply with the N-1 security criterion under transmission congestion. The objective is to minimize expected dispatch and reserve costs, together with post contingency corrective redispatch costs, modeling the probability of generation failure and associated post contingency states. The characteristics of the scheduling problem are exploited to formulate a computationally efficient method, consistent with established operational practices. We simulated the distribution of locational contingency reserves on the IEEE RTS96 system and compared the results with the conventional deterministic method. We found that assigning locational spinning reserves can guarantee an N-1 secure dispatch accounting for transmission congestion at a reasonable extra cost. The simulations also showed little value of allocating downward reserves but sizable operating savings from co-optimizing locational nonspinning reserves. Overall, the results indicate the computational tractability of the proposed method. Part II presents a distributed generation scheduling model to optimally allocate energy and spinning reserves among competing generators in a day-ahead market. The model is based on the coordination between individual generators and a market entity. The proposed method uses forecasting, augmented pricing and locational signals to induce efficient commitment of generators based on firm

Can Life Begin on Enceladus? A Perspective from Hydrothermal Chemistry.

Science.gov (United States)

Deamer, David; Damer, Bruce

2017-09-01

Enceladus is a target of future missions designed to search for existing life or its precursors. Recent flybys of Enceladus by the Cassini probe have confirmed the existence of a long-lived global ocean laced with organic compounds and biologically available nitrogen. This immediately suggests the possibility that life could have begun and may still exist on Enceladus. Here we will compare the properties of two proposed sites for the origin of life on Earth-hydrothermal vents on the ocean floor and hydrothermal volcanic fields at the surface-and ask whether similar conditions could have fostered the origin of life on Enceladus. The answer depends on which of the two sites would be more conducive for the chemical evolution leading to life's origin. A hydrothermal vent origin would allow life to begin in the Enceladus ocean, but if the origin of life requires freshwater hydrothermal pools undergoing wet-dry cycles, the Enceladus ocean could be habitable but lifeless. These arguments also apply directly to Europa and indirectly to early Mars. Key Words: Enceladus-Hydrothermal vents-Hydrothermal fields-Origin of life. Astrobiology 17, 834-839.

Hydrothermal carbonization and torrefaction of grape pomace: a comparative evaluation.

Science.gov (United States)

Pala, Mehmet; Kantarli, Ismail Cem; Buyukisik, Hasan Baha; Yanik, Jale

2014-06-01

Grape pomace was treated by hydrothermal carbonization (sub-critical water, 175-275°C) and torrefaction (nitrogen atmosphere, 250 and 300°C), with mass yield of solid product (char) ranging between 47% and 78%, and energy densification ratio to 1.42-1.15 of the original feedstock. The chars were characterised with respect to their fuel properties, morphological and structural properties and combustion characteristics. The hydrothermal carbonization produced the char with greater energy density than torrefaction. The chars from torrefaction were found to be more aromatic in nature than that from hydrothermal carbonization. Hydrothermal carbonization process produced the char having high combustion reactivity. Most interesting was the finding that aqueous phase from hydrothermal carbonization had antioxidant activity. The results obtained in this study showed that HTC appears to be promising process for a winery waste having high moisture content. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cuprous oxide thin films grown by hydrothermal electrochemical deposition technique

International Nuclear Information System (INIS)

Majumder, M.; Biswas, I.; Pujaru, S.; Chakraborty, A.K.

2015-01-01

Semiconducting cuprous oxide films were grown by a hydrothermal electro-deposition technique on metal (Cu) and glass (ITO) substrates between 60 °C and 100 °C. X-ray diffraction studies reveal the formation of cubic cuprous oxide films in different preferred orientations depending upon the deposition technique used. Film growth, uniformity, grain size, optical band gap and photoelectrochemical response were found to improve in the hydrothermal electrochemical deposition technique. - Highlights: • Cu 2 O thin films were grown on Cu and glass substrates. • Conventional and hydrothermal electrochemical deposition techniques were used. • Hydrothermal electrochemical growth showed improved morphology, thickness and optical band gap

TVA's nuclear power plant experience

International Nuclear Information System (INIS)

Willis, W.F.

1979-01-01

This paper reviews TVA's nuclear power plant design and construction experience in terms of schedule and capital costs. The completed plant in commercial operation at Browns Ferry and six additional plants currently under construction represent the nation's largest single commitment to nuclear power and an ultimate investment of $12 billion by 1986. The presentation is made in three separate phases. Phase one will recapitulate the status of the nuclear power industry in 1966 and set forth the assumptions used for estimating capital costs and projecting project schedules for the first TVA units. Phase two describes what happened to the program in the hectic early 1979's in terms of expansion of scope (particularly for safety features), the dramatic increase in regulatory requirements, vendor problems, stretchout of project schedules, and unprecedented inflation. Phase three addresses the assumptions used today in estimating schedules and plant costs for the next ten-year period

Hydrothermal dolomite reservoir facies in the Sinian Dengying Fm, central Sichuan Basin

Directory of Open Access Journals (Sweden)

Yuqiang Jiang

2017-07-01

Full Text Available The Upper Sinian Dengying Fm is the focus of natural gas exploration in the central part of the Sichuan Basin (central Sichuan Basin in recent years. Especially, epigenic karstification and its resulted reservoir-seepage spaces have always been the focal points in researches. Based on the petrographic characteristics of drilling cuttings and core samples, and through experimental analysis by using trace elements, isotopes, and cathodoluminescence, the Dengying Fm dolomite was demonstrated to have matrix recrystallized dolomite (MRD, filled saddle dolomite (FSD (the mean homogenization temperature of inclusion: 178.5 °C, high concentrations of Fe & Mn, slightly positive 87Sr/86Sr value and hydrothermal minerals combination (including sphalerite, galena, pyrite, and quartz, etc.. Thus, it was proposed that hydrothermal dolomite reservoir facies (HDRF exist in the Dengying Fm dolomite, in other words, the dolomite reservoir is composed of hydrothermal dissolved pores, intercrystalline pores of hydrothermal origin, hydrothermal caverns and expanded fractures, and was formed due to the reworking of hydrothermal fluid on tight matrix dolomite. Identification marks are presented in terms of petrography and geochemistry so that hydrothermal dolomite reservoir facies can be effectively recognized and identified. It is concluded that the development of hydrothermal dolomite reservoir facies in this area are preliminary controlled by deep and large basement faults and the strength of hydrothermal fluids.

Impact-generated Hydrothermal Activity at the Chicxulub Crater

Science.gov (United States)

Kring, D. A.; Zurcher, L.; Abramov, O.

2007-05-01

Borehole samples recovered from PEMEX exploration boreholes and an ICDP scientific borehole indicate the Chicxulub impact event generated hydrothermal alteration throughout a large volume of the Maya Block beneath the crater floor and extending across the bulk of the ~180 km diameter crater. The first indications of hydrothermal alteration were observed in the crater discovery samples from the Yucatan-6 borehole and manifest itself in the form of anhydrite and quartz veins. Continuous core from the Yaxcopoil-1 borehole reveal a more complex and temporally extensive alteration sequence: following a brief period at high temperatures, impact- melt-bearing polymict breccias and a thin, underlying unit of impact melt were subjected to metasomatism, producing alkali feldspar, sphene, apatite, and magnetite. As the system continued to cool, smectite-series phyllosilicates appeared. A saline solution was involved. Stable isotopes suggest the fluid was dominated by a basinal brine created mostly from existing groundwater of the Yucatan Peninsula, although contributions from down-welling water also occurred in some parts of the system. Numerical modeling of the hydrothermal system suggests circulation occurred for 1.5 to 2.3 Myr, depending on the permeability of the system. Our understanding of the hydrothermal system, however, is still crude. Additional core recovery projects, particularly into the central melt sheet, are needed to better evaluate the extent and duration of hydrothermal alteration.

Hydrothermal contamination of public supply wells in Napa and Sonoma Valleys, California

International Nuclear Information System (INIS)

Forrest, M.J.; Kulongoski, J.T.; Edwards, M.S.; Farrar, C.D.; Belitz, K.; Norris, R.D.

2013-01-01

Highlights: ► We analyzed the geochemistry of 44 public supply wells in Napa and Sonoma Valleys. ► We investigated mixing of groundwater with hydrothermal fluids. ► We used multivariate statistical analyses and modeling to characterize wells. ► We found that nine public supply wells contained 14–30% hydrothermal fluids. ► Some contaminated wells contain potentially harmful concentrations of As, F and B. - Abstract: Groundwater chemistry and isotope data from 44 public supply wells in the Napa and Sonoma Valleys, California were determined to investigate mixing of relatively shallow groundwater with deeper hydrothermal fluids. Multivariate analyses including Cluster Analyses, Multidimensional Scaling (MDS), Principal Components Analyses (PCA), Analysis of Similarities (ANOSIM), and Similarity Percentage Analyses (SIMPER) were used to elucidate constituent distribution patterns, determine which constituents are significantly associated with these hydrothermal systems, and investigate hydrothermal contamination of local groundwater used for drinking water. Multivariate statistical analyses were essential to this study because traditional methods, such as mixing tests involving single species (e.g. Cl or SiO 2 ) were incapable of quantifying component proportions due to mixing of multiple water types. Based on these analyses, water samples collected from the wells were broadly classified as fresh groundwater, saline waters, hydrothermal fluids, or mixed hydrothermal fluids/meteoric water wells. The Multivariate Mixing and Mass-balance (M3) model was applied in order to determine the proportion of hydrothermal fluids, saline water, and fresh groundwater in each sample. Major ions, isotopes, and physical parameters of the waters were used to characterize the hydrothermal fluids as Na–Cl type, with significant enrichment in the trace elements As, B, F and Li. Five of the wells from this study were classified as hydrothermal, 28 as fresh groundwater, two as

Instructions, multiple schedules, and extinction: Distinguishing rule-governed from schedule-controlled behavior.

Science.gov (United States)

Hayes, S C; Brownstein, A J; Haas, J R; Greenway, D E

1986-09-01

Schedule sensitivity has usually been examined either through a multiple schedule or through changes in schedules after steady-state responding has been established. This study compared the effects of these two procedures when various instructions were given. Fifty-five college students responded in two 32-min sessions under a multiple fixed-ratio 18/differential-reinforcement-of-low-rate 6-s schedule, followed by one session of extinction. Some subjects received no instructions regarding the appropriate rates of responding, whereas others received instructions to respond slowly, rapidly, or both. Relative to the schedule in operation, the instructions were minimal, partially inaccurate, or accurate. When there was little schedule sensitivity in the multiple schedule, there was little in extinction. When apparently schedule-sensitive responding occurred in the multiple schedule, however, sensitivity in extinction occurred only if differential responding in the multiple schedule could not be due to rules supplied by the experimenter. This evidence shows that rule-governed behavior that occurs in the form of schedule-sensitive behavior may not in fact become schedule-sensitive even though it makes contact with the scheduled reinforcers.

Hydrothermal activity at slow-spreading ridges: variability and importance of magmatic controls

Science.gov (United States)

Escartin, Javier

2016-04-01

Hydrothermal activity along mid-ocean ridge axes is ubiquitous, associated with mass, chemical, and heat exchanges between the deep lithosphere and the overlying envelopes, and sustaining chemiosynthetic ecosystems at the seafloor. Compared with hydrothermal fields at fast-spreading ridges, those at slow spreading ones show a large variability as their location and nature is controlled or influenced by several parameters that are inter-related: a) tectonic setting, ranging from 'volcanic systems' (along the rift valley floor, volcanic ridges, seamounts), to 'tectonic' ones (rift-bounding faults, oceanic detachment faults); b) the nature of the host rock, owing to compositional heterogeneity of slow-spreading lithosphere (basalt, gabbro, peridotite); c) the type of heat source (magmatic bodies at depth, hot lithosphere, serpentinization reactions); d) and the associated temperature of outflow fluids (high- vs.- low temperature venting and their relative proportion). A systematic review of the distribution and characteristics of hydrothermal fields along the slow-spreading Mid-Atlantic Ridge suggests that long-lived hydrothermal activity is concentrated either at oceanic detachment faults, or along volcanic segments with evidence of robust magma supply to the axis. A detailed study of the magmatically robust Lucky Strike segment suggests that all present and past hydrothermal activity is found at the center of the segment. The association of these fields to central volcanos, and the absence of indicators of hydrothermal activity along the remaining of the ridge segment, suggests that long-lived hydrothermal activity in these volcanic systems is maintained by the enhanced melt supply and the associated magma chamber(s) required to build these volcanic edifices. In this setting, hydrothermal outflow zones at the seafloor are systematically controlled by faults, indicating that hydrothermal fluids in the shallow crust exploit permeable fault zones to circulate. While

Microwave hydrothermal synthesis and upconversion properties of Yb3+/Er3+ doped YVO4 nanoparticles.

Science.gov (United States)

Kshetri, Yuwaraj K; Regmi, Chhabilal; Kim, Hak-Soo; Lee, Soo Wohn; Kim, Tae-Ho

2018-05-18

Yb 3+ and Er 3+ doped YVO 4 (Yb 3+ /Er 3+ :YVO 4 ) nanoparticles with highly efficient near-infrared to visible upconversion properties have been synthesized by microwave hydrothermal process. Uniform-sized Yb 3+ /Er 3+ :YVO 4 nanoparticles were synthesized within 1 h at 140 °C which is relatively faster than the conventional hydrothermal process. Under 980 nm laser excitation, strong green and less strong red emissions are observed which are attributed to 2 H 11/2 , 4 S 3/2 to 4 I 15/2 and 4 F 9/2 to 4 I 15/2 transitions of Er 3+ respectively. The emission intensity is found to depend strongly on the concentration of Yb 3+ . The quadratic dependence of upconversion intensity on the excitation power indicates that the upconversion process is governed by two-photon absorption process.

Microwave hydrothermal synthesis and upconversion properties of Yb3+/Er3+ doped YVO4 nanoparticles

Science.gov (United States)

Kshetri, Yuwaraj K.; Regmi, Chhabilal; Kim, Hak-Soo; Wohn Lee, Soo; Kim, Tae-Ho

2018-05-01

Yb3+ and Er3+ doped YVO4 (Yb3+/Er3+:YVO4) nanoparticles with highly efficient near-infrared to visible upconversion properties have been synthesized by microwave hydrothermal process. Uniform-sized Yb3+/Er3+:YVO4 nanoparticles were synthesized within 1 h at 140 °C which is relatively faster than the conventional hydrothermal process. Under 980 nm laser excitation, strong green and less strong red emissions are observed which are attributed to 2H11/2, 4S3/2 to 4I15/2 and 4F9/2 to 4I15/2 transitions of Er3+ respectively. The emission intensity is found to depend strongly on the concentration of Yb3+. The quadratic dependence of upconversion intensity on the excitation power indicates that the upconversion process is governed by two-photon absorption process.

Effects of iron-containing minerals on hydrothermal reactions of ketones

Science.gov (United States)

Yang, Ziming; Gould, Ian R.; Williams, Lynda B.; Hartnett, Hilairy E.; Shock, Everett L.

2018-02-01

Hydrothermal organic transformations occurring in geochemical processes are influenced by the surrounding environments including rocks and minerals. This work is focused on the effects of five common minerals on reactions of a model ketone substrate, dibenzylketone (DBK), in an experimental hydrothermal system. Ketones play a central role in many hydrothermal organic functional group transformations, such as those converting hydrocarbons to oxygenated compounds; however, how these minerals control the hydrothermal chemistry of ketones is poorly understood. Under the hydrothermal conditions of 300 °C and 70 MPa for up to 168 h, we observed that, while quartz (SiO2) and corundum (Al2O3) had no detectable effect on the hydrothermal reactions of DBK, iron-containing minerals, such as hematite (Fe2O3), magnetite (Fe3O4), and troilite (synthetic FeS), accelerated the reaction of DBK by up to an order of magnitude. We observed that fragmentation products, such as toluene and bibenzyl, dominated in the presence of hematite or magnetite, while use of troilite gave primarily the reduction products, e.g., 1, 3-diphenyl-propane and 1, 3-diphenyl-2-propanol. The roles of the three iron minerals in these transformations were further explored by (1) control experiments with various mineral surface areas, (2) measuring H2 in hydrothermal solutions, and (3) determining hydrogen balance among the organic products. These results suggest the reactions catalyzed by iron oxides (hematite and magnetite) are promoted mainly by the mineral surfaces, whereas the sulfide mineral (troilite) facilitated the reduction of ketone in the reaction solution. Therefore, this work not only provides a useful chemical approach to study and uncover complicated hydrothermal organic-mineral interactions, but also fosters a mechanistic understanding of ketone reactions in the deep carbon cycle.

Low-Complexity Scheduling and Power Adaptation for Coordinated Cloud-Radio Access Networks

KAUST Repository

Douik, Ahmed; Dahrouj, Hayssam; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

2017-01-01

In practical wireless systems, the successful implementation of resource allocation techniques strongly depends on the algorithmic complexity. Consider a cloud-radio access network (CRAN), where the central cloud is responsible for scheduling

Coastal submarine hydrothermal activity off northern Baja California

International Nuclear Information System (INIS)

Vidal, V.M.V.; Vidal, F.V.; Isaacs, J.D.; Young, D.R.

1978-01-01

In situ observations of submarine hydrothermal activity have been conducted in Punta Banda. Baja Califronia, Mexico, approximately 400 m from the coast and at a seawater depth of 30 m. The hydrothermal activity occurs within the Agua Blanca Fault, a major transverse structure of Northern Baja California. Hot springwater samples have been collected and analyzed. Marked differences exist between the submarine hot springwater, local land hot springwaters, groundwater, and local seawater. SiO 2 , HCO 3 , Ca, K, Li, B, Ba, Rb, Fe, Mn, As, and Zn are enriched in the submarine hot springwater, while Cl, Na, So 4 2 , Mg, Cu, Ni, Cd, Cr, and perhaps Pb are depleted in relation to average and local seawater values. Very high temperatures, at the hydrothermal vents, have been recorded (102 0 C at 4-atm pressure). Visible gaseous emanations rich in CH 4 and N 2 coexist with the hydrothermal solutions. Metalliferous deposits, pyrite, have been encountered with high concentrations of Fe, S, Si, Al, Mn, Ca, and the volatile elements As, Hg, Sb, and Tl, X ray dispersive spectrometry (1500-ppm detection limit). X ray diffraction, and scanning electron microscopy of the isolated metalliferous precipitates indicate that the principal products of precipitation are pyrite and gypsum accompanied by minor amounts of amorphous material containing Si and Al. Chemical analyses and XRD of the reference control rocks of the locality (volcanics) versus the hydrothermally altered rocks indicate that high-temperature and high-pressure water-rock interactions can in part explain the water chemistry characteristics of the submarine hydrothermal waters. Their long residence time, the occurrence of an extensive marine sedimentary formation, their association with CH 4 and their similarities with connate waters of oil and gas fields suggest that another component of their genesis could be in cation exchange reactions within deeply buried sediments of marine origin

Schedules of Controlled Substances: Temporary Placement of 4-Fluoroisobutyryl Fentanyl into Schedule I. Temporary scheduling order.

Science.gov (United States)

2017-05-03

The Administrator of the Drug Enforcement Administration is issuing this temporary scheduling order to schedule the synthetic opioid, N-(4-fluorophenyl)-N-(1-phenethylpiperidin-4-yl)isobutyramide (4-fluoroisobutyryl fentanyl or para-fluoroisobutyryl fentanyl), and its isomers, esters, ethers, salts and salts of isomers, esters, and ethers, into schedule I pursuant to the temporary scheduling provisions of the Controlled Substances Act. This action is based on a finding by the Administrator that the placement of 4-fluoroisobutyryl fentanyl into schedule I of the Controlled Substances Act is necessary to avoid an imminent hazard to the public safety. As a result of this order, the regulatory controls and administrative, civil, and criminal sanctions applicable to schedule I controlled substances will be imposed on persons who handle (manufacture, distribute, reverse distribute, import, export, engage in research, conduct instructional activities or chemical analysis, or possess), or propose to handle, 4-fluoroisobutyryl fentanyl.

Application of 3D model in the schedule management of nuclear power plant construction

International Nuclear Information System (INIS)

Nian Fayang

2009-01-01

While 3D technology has been widely used in engineering design, the 3D model of engineering design also includes information that can be used to construction. By the visual interface, the 3D model can be used in different aspects of construction. By linking the 3D model with the construction schedule, the 4D model can be created, through which the visual manage of the construction schedule can be achieved. (authors)

76 FR 40306 - Harmonizing Schedule I Drug Requirements

Science.gov (United States)

2011-07-08

... an amphetamine, narcotic, or any habit-forming drug, are not medically qualified to operate a... of the 1984 Act also grants the Secretary broad power in carrying out motor carrier safety statutes...: Controlled substances on the DEA Schedule I, amphetamines, narcotics, or other habit-forming drugs. Section...

Guidelines of Decommissioning Schedule Establishment

Energy Technology Data Exchange (ETDEWEB)

Oh, Jae Yong; Yun, Taesik; Kim, Younggook; Kim, Hee-Geun [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

Decommissioning has recently become an issue highlighted in Korea due to the Permanent Shutdown (PS) of Kori-1 plant. Since Korea Hydro and Nuclear Power (KHNP) Company decided the PS of Kori-1 instead of further continued operation, Kori-1 will be the first decommissioning plant of the commercial reactors in Korea. Korean regulatory authority demands Initial Decommissioning Plan (IDP) for all the plants in operation and under construction. In addition, decommissioning should be considered for the completion of the life cycle of NPPs. To date, Korea has no experience regarding decommissioning of the commercial reactor and a lot of uncertainties will be expected due to its site-specific factors. However, optimized decommissioning process schedule must be indispensable in the safety and economic efficiency of the project. Differed from USA, Korea has no experience and know-hows of the operation and site management for decommissioning. Hence, in Korea, establishment of decommissioning schedule has to give more weight to safety than precedent cases. More economical and rational schedule will be composed by collecting and analyzing the experience data and site-specific data and information as the decommissioning progresses. In a long-range outlook, KHNP having capability of NPP decommissioning will try to decommissioning business in Korea and foreign countries.

Scheduling Parallel Jobs Using Migration and Consolidation in the Cloud

Directory of Open Access Journals (Sweden)

Xiaocheng Liu

2012-01-01

Full Text Available An increasing number of high performance computing parallel applications leverages the power of the cloud for parallel processing. How to schedule the parallel applications to improve the quality of service is the key to the successful host of parallel applications in the cloud. The large scale of the cloud makes the parallel job scheduling more complicated as even simple parallel job scheduling problem is NP-complete. In this paper, we propose a parallel job scheduling algorithm named MEASY. MEASY adopts migration and consolidation to enhance the most popular EASY scheduling algorithm. Our extensive experiments on well-known workloads show that our algorithm takes very good care of the quality of service. For two common parallel job scheduling objectives, our algorithm produces an up to 41.1% and an average of 23.1% improvement on the average response time; an up to 82.9% and an average of 69.3% improvement on the average slowdown. Our algorithm is robust even in terms that it allows inaccurate CPU usage estimation and high migration cost. Our approach involves trivial modification on EASY and requires no additional technique; it is practical and effective in the cloud environment.

Scheduling techniques in the Request Oriented Scheduling Engine (ROSE)

Science.gov (United States)

Zoch, David R.

1991-01-01

Scheduling techniques in the ROSE are presented in the form of the viewgraphs. The following subject areas are covered: agenda; ROSE summary and history; NCC-ROSE task goals; accomplishments; ROSE timeline manager; scheduling concerns; current and ROSE approaches; initial scheduling; BFSSE overview and example; and summary.

18 CFR 154.202 - Filings to initiate a new rate schedule.

Science.gov (United States)

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Filings to initiate a new rate schedule. 154.202 Section 154.202 Conservation of Power and Water Resources FEDERAL ENERGY... contain a notice of the interdependence. (b) If a new service, facility, or rate is specifically...

Effect of hydrothermal process for inorganic alumina sol on crystal structure of alumina gel

Directory of Open Access Journals (Sweden)

K. Yamamura

2016-09-01

Full Text Available This paper reports the effect of a hydrothermal process for alumina sol on the crystal structure of alumina gel derived from hydrothermally treated alumina sol to help push forward the development of low temperature synthesis of α-Al2O3. White precipitate of aluminum hydroxide was prepared with a homogeneous precipitation method using aluminum nitrate and urea in aqueous solution. The obtained aluminum hydroxide precipitate was peptized by using acetic acid at room temperature, which resulted in the production of a transparent alumina sol. The alumina sol was treated with a hydrothermal process and transformed into an alumina gel film by drying at room temperature. Crystallization of the alumina gel to α-Al2O3 with 900 °C annealing was dominant for a hydrothermal temperature of 100 °C and a hydrothermal time of 60 min, as production of diaspore-like species was promoted with the hydrothermal temperature and time. Excess treatments with hydrothermal processes at higher hydrothermal temperature for longer hydrothermal time prevented the alumina gel from being crystallized to α-Al2O3 because the excess hydrothermal treatments promoted production of boehmite.

Hydrothermal treatment of coprecipitated YSZ powders

International Nuclear Information System (INIS)

Arakaki, Alexander Rodrigo; Yoshito, Walter Kenji; Ussui, Valter; Lazar, Dolores Ribeiro Ricci

2009-01-01

Zirconia stabilized with 8.5 mol% yttria (YSZ) were synthesized by coprecipitation and resulting gels were hydrothermally treated at 200°C and 220 PSI for 4, 8 and 16 hours. Products were oven dried at 70°C for 24 hours, uniaxially pressed as pellets and sintered at 1500 °C for 1 hour. Powders were characterized for surface area with N 2 gas adsorption, X-ray diffraction, laser diffraction granulometric analysis and scanning and transmission electronic microscopy. Density of ceramics was measured by an immersion method based on the Archimedes principle. Results showed that powders dried at 70°C are amorphous and after treatment has tetragonal/cubic symmetry. Surface area of powders presented a significant reduction after hydrothermal treatment. Ceramics prepared from hydrothermally treated powders have higher green density but sintered pellets are less dense when compared to that made with powders calcined at 800°C for 1 hour due to the agglomerate state of powders. Solvothermal treatment is a promising procedure to enhance density. (author)

Radionuclides in hydrothermal systems as indicators of repository conditions

International Nuclear Information System (INIS)

Wollenberg, H.A.; Flexser, S.; Smith, A.R.

1990-11-01

Hydrothermal systems in tuffaceous and older sedimentary rocks contain evidence of the interaction of radionuclides in fluids with rock matrix minerals and with materials lining fractures, in settings somewhat analogous to the candidate repository site at Yucca Mountain, NV. Earlier studies encompassed the occurrences of U and Th in a ''fossil'' hydrothermal system in tuffaceous rock of the San Juan Mountains volcanic field, CO. More recent and ongoing studies examine active hydrothermal systems in calderas at Long Valley, CA and Valles, NM. At the Nevada Test Site, occurrences of U and Th in fractured and unfractured rhyolitic tuff that was heated to simulate the introduction of radioactive waste are also under investigation. Observations to date suggest that U is mobile in hydrothermal systems, but that localized reducing environments provided by Fe-rich minerals and/or carbonaceous material concentrate U and thus attenuate its migration. 11 refs., 6 figs., 1 tab

Geochemical constraints on chemolithoautotrophic reactions in hydrothermal systems

Science.gov (United States)

Shock, Everett L.; McCollom, Thomas; Schulte, Mitchell D.

1995-06-01

Thermodynamic calculations provide the means to quantify the chemical disequilibrium inherent in the mixing of redeuced hydrothermal fluids with seawater. The chemical energy available for metabolic processes in these environments can be evaluated by taking into account the pressure and temperature dependence of the apparent standard Gibbs free energies of reactions in the S-H2-H2O system together with geochemical constraints on pH, activities of aqueous sulfur species and fugacities of H2 and/or O2. Using present-day mixing of hydrothermal fluids and seawater as a starting point, it is shown that each mole of H2S entering seawater from hydrothermal fluids represents about 200,000 calories of chemical energy for metabolic systems able to catalyze H2S oxidation. Extrapolating to the early Earth, which was likely to have had an atmosphere more reduced than at present, shows that this chemical energy may have been a factor of two or so less. Nevertheless, mixing of hydrothermal fluids with seawater would have been an abundant source of chemical energy, and an inevitable consequence of the presence of an ocean on an initially hot Earth. The amount of energy available was more than enough for organic synthesis from CO2 or CO, and/or polymer formation, indicating that the vicinity of hydrothermal systems at the sea floor was an ideal location for the emergence of the first chemolithoautotrophic metabolic systems.

Hybrid Scheduling/Signal-Level Coordination in the Downlink of Multi-Cloud Radio-Access Networks

KAUST Repository

Douik, Ahmed

2016-03-28

In the context of resource allocation in cloud- radio access networks, recent studies assume either signal-level or scheduling-level coordination. This paper, instead, considers a hybrid level of coordination for the scheduling problem in the downlink of a multi-cloud radio- access network, so as to benefit from both scheduling policies. Consider a multi-cloud radio access network, where each cloud is connected to several base-stations (BSs) via high capacity links, and therefore allows joint signal processing between them. Across the multiple clouds, however, only scheduling-level coordination is permitted, as it requires a lower level of backhaul communication. The frame structure of every BS is composed of various time/frequency blocks, called power- zones (PZs), and kept at fixed power level. The paper addresses the problem of maximizing a network-wide utility by associating users to clouds and scheduling them to the PZs, under the practical constraints that each user is scheduled, at most, to a single cloud, but possibly to many BSs within the cloud, and can be served by one or more distinct PZs within the BSs\\' frame. The paper solves the problem using graph theory techniques by constructing the conflict graph. The scheduling problem is, then, shown to be equivalent to a maximum- weight independent set problem in the constructed graph, in which each vertex symbolizes an association of cloud, user, BS and PZ, with a weight representing the utility of that association. Simulation results suggest that the proposed hybrid scheduling strategy provides appreciable gain as compared to the scheduling-level coordinated networks, with a negligible degradation to signal-level coordination.

An Arrival and Departure Time Predictor for Scheduling Communication in Opportunistic IoT

Science.gov (United States)

Pozza, Riccardo; Georgoulas, Stylianos; Moessner, Klaus; Nati, Michele; Gluhak, Alexander; Krco, Srdjan

2016-01-01

In this article, an Arrival and Departure Time Predictor (ADTP) for scheduling communication in opportunistic Internet of Things (IoT) is presented. The proposed algorithm learns about temporal patterns of encounters between IoT devices and predicts future arrival and departure times, therefore future contact durations. By relying on such predictions, a neighbour discovery scheduler is proposed, capable of jointly optimizing discovery latency and power consumption in order to maximize communication time when contacts are expected with high probability and, at the same time, saving power when contacts are expected with low probability. A comprehensive performance evaluation with different sets of synthetic and real world traces shows that ADTP performs favourably with respect to previous state of the art. This prediction framework opens opportunities for transmission planners and schedulers optimizing not only neighbour discovery, but the entire communication process. PMID:27827909

An Arrival and Departure Time Predictor for Scheduling Communication in Opportunistic IoT.

Science.gov (United States)

Pozza, Riccardo; Georgoulas, Stylianos; Moessner, Klaus; Nati, Michele; Gluhak, Alexander; Krco, Srdjan

2016-11-04

In this article, an Arrival and Departure Time Predictor (ADTP) for scheduling communication in opportunistic Internet of Things (IoT) is presented. The proposed algorithm learns about temporal patterns of encounters between IoT devices and predicts future arrival and departure times, therefore future contact durations. By relying on such predictions, a neighbour discovery scheduler is proposed, capable of jointly optimizing discovery latency and power consumption in order to maximize communication time when contacts are expected with high probability and, at the same time, saving power when contacts are expected with low probability. A comprehensive performance evaluation with different sets of synthetic and real world traces shows that ADTP performs favourably with respect to previous state of the art. This prediction framework opens opportunities for transmission planners and schedulers optimizing not only neighbour discovery, but the entire communication process.

Direct catalytic hydrothermal liquefaction of spirulina to biofuels with hydrogen

Science.gov (United States)

Zeng, Qin; Liao, Hansheng; Zhou, Shiqin; Li, Qiuping; Wang, Lu; Yu, Zhihao; Jing, Li

2018-01-01

We report herein on acquiring biofuels from direct catalytic hydrothermal liquefaction of spirulina. The component of bio-oil from direct catalytic hydrothermal liquefaction was similar to that from two independent processes (including liquefaction and upgrading of biocrude). However, one step process has higher carbon recovery, due to the less loss of carbons. It was demonstrated that the yield and HHV of bio-oil from direct catalytic algae with hydrothermal condition is higher than that from two independent processes.

Genetic diversity of archaea in deep-sea hydrothermal vent environments.

Science.gov (United States)

Takai, K; Horikoshi, K

1999-08-01

Molecular phylogenetic analysis of naturally occurring archaeal communities in deep-sea hydrothermal vent environments was carried out by PCR-mediated small subunit rRNA gene (SSU rDNA) sequencing. As determined through partial sequencing of rDNA clones amplified with archaea-specific primers, the archaeal populations in deep-sea hydrothermal vent environments showed a great genetic diversity, and most members of these populations appeared to be uncultivated and unidentified organisms. In the phylogenetic analysis, a number of rDNA sequences obtained from deep-sea hydrothermal vents were placed in deep lineages of the crenarchaeotic phylum prior to the divergence of cultivated thermophilic members of the crenarchaeota or between thermophilic members of the euryarchaeota and members of the methanogen-halophile clade. Whole cell in situ hybridization analysis suggested that some microorganisms of novel phylotypes predicted by molecular phylogenetic analysis were likely present in deep-sea hydrothermal vent environments. These findings expand our view of the genetic diversity of archaea in deep-sea hydrothermal vent environments and of the phylogenetic organization of archaea.

The development of stochastic process modeling through risk analysis derived from scheduling of NPP project

International Nuclear Information System (INIS)

Lee, Kwang Ho; Roh, Myung Sub

2013-01-01

There are so many different factors to consider when constructing a nuclear power plant successfully from planning to decommissioning. According to PMBOK, all projects have nine domains from a holistic project management perspective. They are equally important to all projects, however, this study focuses mostly on the processes required to manage timely completion of the project and conduct risk management. The overall objective of this study is to let you know what the risk analysis derived from scheduling of NPP project is, and understand how to implement the stochastic process modeling through risk management. Building the Nuclear Power Plant is required a great deal of time and fundamental knowledge related to all engineering. That means that integrated project scheduling management with so many activities is necessary and very important. Simulation techniques for scheduling of NPP project using Open Plan program, Crystal Ball program, and Minitab program can be useful tools for designing optimal schedule planning. Thus far, Open Plan and Monte Carlo programs have been used to calculate the critical path for scheduling network analysis. And also, Minitab program has been applied to monitor the scheduling risk. This approach to stochastic modeling through risk analysis of project activities is very useful for optimizing the schedules of activities using Critical Path Method and managing the scheduling control of NPP project. This study has shown new approach to optimal scheduling of NPP project, however, this does not consider the characteristic of activities according to the NPP site conditions. Hence, this study needs more research considering those factors

The development of stochastic process modeling through risk analysis derived from scheduling of NPP project

Energy Technology Data Exchange (ETDEWEB)

Lee, Kwang Ho; Roh, Myung Sub [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

2013-10-15

There are so many different factors to consider when constructing a nuclear power plant successfully from planning to decommissioning. According to PMBOK, all projects have nine domains from a holistic project management perspective. They are equally important to all projects, however, this study focuses mostly on the processes required to manage timely completion of the project and conduct risk management. The overall objective of this study is to let you know what the risk analysis derived from scheduling of NPP project is, and understand how to implement the stochastic process modeling through risk management. Building the Nuclear Power Plant is required a great deal of time and fundamental knowledge related to all engineering. That means that integrated project scheduling management with so many activities is necessary and very important. Simulation techniques for scheduling of NPP project using Open Plan program, Crystal Ball program, and Minitab program can be useful tools for designing optimal schedule planning. Thus far, Open Plan and Monte Carlo programs have been used to calculate the critical path for scheduling network analysis. And also, Minitab program has been applied to monitor the scheduling risk. This approach to stochastic modeling through risk analysis of project activities is very useful for optimizing the schedules of activities using Critical Path Method and managing the scheduling control of NPP project. This study has shown new approach to optimal scheduling of NPP project, however, this does not consider the characteristic of activities according to the NPP site conditions. Hence, this study needs more research considering those factors.

Human reliability and plant operating efficiency: Are 12-hour work schedules cause for concern?

International Nuclear Information System (INIS)

Baker, T.L.

1992-01-01

Since the introduction of 12-h shifts to the US nuclear power industry only 8 yr ago, compressed workweek schedules have proliferated among operations departments at a phenomenal rate. Many plants that continue to use 8-h shifts during normal operations routinely change to scheduled 12-h shifts during refueling or maintenance outages. The most critical issue in the use of extended work shifts is whether alertness, physical stamina, or mental performance are compromised to the point of reducing safety or efficiency of nuclear power plant operation. Laboratory and field research sponsored by the National Institute of Occupational Safety and Health suggests that alertness, measured by self-ratings, and mental performance, measured by computer-based performance tests, are impaired on 12-h shifts compared with 8-h shifts. In contrast to these findings, plant operating efficiency and operator performance have been rated as improved in two field studies conducted in operating nuclear power plants (Fast Flux Test Facility, Washington and Ontario Hydro, Canada). A recent Electric Power Research Institute review of nuclear industry experience with 12-h shifts also suggests an overwhelmingly positive rating of 12-h schedules from both control room operators and management

Multi-agent system for energy resource scheduling of integrated microgrids in a distributed system

International Nuclear Information System (INIS)

Logenthiran, T.; Srinivasan, Dipti; Khambadkone, Ashwin M.

2011-01-01

This paper proposes a multi-agent system for energy resource scheduling of an islanded power system with distributed resources, which consists of integrated microgrids and lumped loads. Distributed intelligent multi-agent technology is applied to make the power system more reliable, efficient and capable of exploiting and integrating alternative sources of energy. The algorithm behind the proposed energy resource scheduling has three stages. The first stage is to schedule each microgrid individually to satisfy its internal demand. The next stage involves finding the best possible bids for exporting power to the network and compete in a whole sale energy market. The final stage is to reschedule each microgrid individually to satisfy the total demand, which is the addition of internal demand and the demand from the results of the whole sale energy market simulation. The simulation results of a power system with distributed resources comprising three microgrids and five lumped loads show that the proposed multi-agent system allows efficient management of micro-sources with minimum operational cost. The case studies demonstrate that the system is successfully monitored, controlled and operated by means of the developed multi-agent system. (author)

Multi-agent system for energy resource scheduling of integrated microgrids in a distributed system

Energy Technology Data Exchange (ETDEWEB)

Logenthiran, T.; Srinivasan, Dipti; Khambadkone, Ashwin M. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)

2011-01-15

This paper proposes a multi-agent system for energy resource scheduling of an islanded power system with distributed resources, which consists of integrated microgrids and lumped loads. Distributed intelligent multi-agent technology is applied to make the power system more reliable, efficient and capable of exploiting and integrating alternative sources of energy. The algorithm behind the proposed energy resource scheduling has three stages. The first stage is to schedule each microgrid individually to satisfy its internal demand. The next stage involves finding the best possible bids for exporting power to the network and compete in a whole sale energy market. The final stage is to reschedule each microgrid individually to satisfy the total demand, which is the addition of internal demand and the demand from the results of the whole sale energy market simulation. The simulation results of a power system with distributed resources comprising three microgrids and five lumped loads show that the proposed multi-agent system allows efficient management of micro-sources with minimum operational cost. The case studies demonstrate that the system is successfully monitored, controlled and operated by means of the developed multi-agent system. (author)

Fractionation of boron isotopes in Icelandic hydrothermal systems

International Nuclear Information System (INIS)

Aggarwal, J.K.

1995-01-01

Boron isotope ratios have been determined in a variety of different geothermal waters from hydrothermal systems across Iceland. Isotope ratios from the high temperature meteoric water recharged systems reflect the isotope ratio of the host rocks without any apparent fractionation. Seawater recharged geothermal systems exhibit more positive δ 1 1B values than the meteoric water recharged geothermal systems. Water/rock ratios can be assessed from boron isotope ratios in the saline hydrothermal systems. Low temperature hydrothermal systems also exhibit more positive δ 1 1B than the high temperature systems, indicating fractionation of boron due to absorption of the lighter isotope onto secondary minerals. Fractionation of boron in carbonate deposits may indicate the level of equilibrium attained within the systems. (author). 14 refs., 2 figs

Versatile hydrothermal synthesis of one-dimensional composite structures

Science.gov (United States)

Luo, Yonglan

2008-12-01

In this paper we report on a versatile hydrothermal approach developed to fabricate one-dimensional (1D) composite structures. Sulfur and selenium formed liquid and adsorbed onto microrods as droplets and subsequently reacted with metallic ion in solution to produce nanoparticles-decorated composite microrods. 1D composites including ZnO/CdS, ZnO/MnS, ZnO/CuS, ZnO/CdSe, and FeOOH/CdS were successfully made using this hydrothermal strategy and the growth mechanism was also discussed. This hydrothermal strategy is simple and green, and can be extended to the synthesis of various 1D composite structures. Moreover, the interaction between the shell nanoparticles and the one-dimensional nanomaterials were confirmed by photoluminescence investigation of ZnO/CdS.

VALORAGUA: A model for the optimal operating strategy of mixed hydrothermal generating systems

International Nuclear Information System (INIS)

1992-01-01

To provide assistance to its developing Member States in carrying out integrated power system expansion analysis, the International Atomic Energy Agency (IAEA) has developed the computer model called WASP (Wien Automatic System Planning Package). The WASP model has proven to be very useful for this purpose and is accepted worldwide as a sound tool for electricity planning. Notwithstanding its many advantages, certain shortcomings of the methodology have been noticed, in particular with regard to representation of hydroelectric power plants. In order to overcome these shortcomings, the IAEA decided to acquire the computer model called VALORAGUA, developed by the Electricidade de Portugal (EDP), for optimizing the operating strategy of a mixed hydro-thermal power system. This program, when used together with WASP, would allow economic optimization of hydro-thermal power systems with a large hydro component. The objective of the present document is to assist in the use of the VALORAGUA model and its auxiliary codes, as well as to clarify the interconnection between VALORAGUA and the WASP-III model. This report is organized into five main chapters. The first chapter serves as an introduction to all remaining chapters. Chapter 2 defines the input data needed for every component of the electric power system. Chapter 3 presents the output variables of the model within the standard output tables that can be produced by VALORAGUA. Chapter 4 describes in detail all the input data needed by each program. It also includes the list of computer input data corresponding to the example described in Chapter 5, which is used to illustrate the execution of the VALORAGUA modules. Description of how to prepare the hydro data for the WASP-III model from the results obtained with the VALORAGUA model is given in Appendix A. Some auxiliary programs of the VALORAGUA model system, developed by EDP to help the user with the input data preparation, are described in Appendix B. Refs, figs and

Hydrothermal conversion of biomass

NARCIS (Netherlands)

Knezevic, D.

2009-01-01

This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of

Dynamic Appliances Scheduling in Collaborative MicroGrids System

Science.gov (United States)

Bilil, Hasnae; Aniba, Ghassane; Gharavi, Hamid

2017-01-01

In this paper a new approach which is based on a collaborative system of MicroGrids (MG’s), is proposed to enable household appliance scheduling. To achieve this, appliances are categorized into flexible and non-flexible Deferrable Loads (DL’s), according to their electrical components. We propose a dynamic scheduling algorithm where users can systematically manage the operation of their electric appliances. The main challenge is to develop a flattening function calculus (reshaping) for both flexible and non-flexible DL’s. In addition, implementation of the proposed algorithm would require dynamically analyzing two successive multi-objective optimization (MOO) problems. The first targets the activation schedule of non-flexible DL’s and the second deals with the power profiles of flexible DL’s. The MOO problems are resolved by using a fast and elitist multi-objective genetic algorithm (NSGA-II). Finally, in order to show the efficiency of the proposed approach, a case study of a collaborative system that consists of 40 MG’s registered in the load curve for the flattening program has been developed. The results verify that the load curve can indeed become very flat by applying the proposed scheduling approach. PMID:28824226

Project management with dynamic scheduling baseline scheduling, risk analysis and project control

CERN Document Server

Vanhoucke, Mario

2013-01-01

The topic of this book is known as dynamic scheduling, and is used to refer to three dimensions of project management and scheduling: the construction of a baseline schedule and the analysis of a project schedule's risk as preparation of the project control phase during project progress. This dynamic scheduling point of view implicitly assumes that the usability of a project's baseline schedule is rather limited and only acts as a point of reference in the project life cycle.

Consensus based scheduling of storage capacities in a virtual microgrid

DEFF Research Database (Denmark)

Brehm, Robert; Top, Søren; Mátéfi-Tempfli, Stefan

2017-01-01

We present a distributed, decentralized method for coordinated scheduling of charge/discharge intervals of storage capacities in a utility grid integrated microgrid. The decentralized algorithm is based on a consensus scheme and solves an optimisation problem with the objective of minimising......, by use of storage capacities, the power flow over a transformer substation from/to the utility grid integrated microgrid. It is shown that when using this coordinated scheduling algorithm, load profile flattening (peak-shaving) for the utility grid is achieved. Additionally, mutual charge...

Comparison of genetic algorithm and harmony search for generator maintenance scheduling

International Nuclear Information System (INIS)

Khan, L.; Mumtaz, S.; Khattak, A.

2012-01-01

GMS (Generator Maintenance Scheduling) ranks very high in decision making of power generation management. Generators maintenance schedule decides the time period of maintenance tasks and a reliable reserve margin is also maintained during this time period. In this paper, a comparison of GA (Genetic Algorithm) and US (Harmony Search) algorithm is presented to solve generators maintenance scheduling problem for WAPDA (Water And Power Development Authority) Pakistan. GA is a search procedure, which is used in search problems to compute exact and optimized solution. GA is considered as global search heuristic technique. HS algorithm is quite efficient, because the convergence rate of this algorithm is very fast. HS algorithm is based on the concept of music improvisation process of searching for a perfect state of harmony. The two algorithms generate feasible and optimal solutions and overcome the limitations of the conventional methods including extensive computational effort, which increases exponentially as the size of the problem increases. The proposed methods are tested, validated and compared on the WAPDA electric system. (author)

Hydrothermal decomposition of liquid crystal in subcritical water

International Nuclear Information System (INIS)

Zhuang, Xuning; He, Wenzhi; Li, Guangming; Huang, Juwen; Lu, Shangming; Hou, Lianjiao

2014-01-01

Highlights: • Hydrothermal technology can effectively decompose the liquid crystal of 4-octoxy-4'-cyanobiphenyl. • The decomposition rate reached 97.6% under the optimized condition. • Octoxy-4'-cyanobiphenyl was mainly decomposed into simple and innocuous products. • The mechanism analysis reveals the decomposition reaction process. - Abstract: Treatment of liquid crystal has important significance for the environment protection and human health. This study proposed a hydrothermal process to decompose the liquid crystal of 4-octoxy-4′-cyanobiphenyl. Experiments were conducted with a 5.7 mL stainless tube reactor and heated by a salt-bath. Factors affecting the decomposition rate of 4-octoxy-4′-cyanobiphenyl were evaluated with HPLC. The decomposed liquid products were characterized by GC-MS. Under optimized conditions i.e., 0.2 mL H 2 O 2 supply, pH value 6, temperature 275 °C and reaction time 5 min, 97.6% of 4-octoxy-4′-cyanobiphenyl was decomposed into simple and environment-friendly products. Based on the mechanism analysis and products characterization, a possible hydrothermal decomposition pathway was proposed. The results indicate that hydrothermal technology is a promising choice for liquid crystal treatment

NASA scheduling technologies

Science.gov (United States)

Adair, Jerry R.

1994-01-01

This paper is a consolidated report on ten major planning and scheduling systems that have been developed by the National Aeronautics and Space Administration (NASA). A description of each system, its components, and how it could be potentially used in private industry is provided in this paper. The planning and scheduling technology represented by the systems ranges from activity based scheduling employing artificial intelligence (AI) techniques to constraint based, iterative repair scheduling. The space related application domains in which the systems have been deployed vary from Space Shuttle monitoring during launch countdown to long term Hubble Space Telescope (HST) scheduling. This paper also describes any correlation that may exist between the work done on different planning and scheduling systems. Finally, this paper documents the lessons learned from the work and research performed in planning and scheduling technology and describes the areas where future work will be conducted.

Hydrothermal stability of microporous silica and niobia-silica membranes

NARCIS (Netherlands)

Boffa, V.; Blank, David H.A.; ten Elshof, Johan E.

2008-01-01

The hydrothermal stability of microporous niobia–silica membranes was investigated and compared with silica membranes. The membranes were exposed to hydrothermal conditions at 150 and 200 °C for 70 h. The change of pore structure before and after exposure to steam was probed by single-gas permeation

Two-Dimensional NMR Evidence for Cleavage of Lignin and Xylan Substituents in Wheat Straw Through Hydrothermal Pretreatment and Enzymatic Hydrolysis

Science.gov (United States)

Daniel J. Yelle; Prasad Kaparaju; Christopher G. Hunt; Kolby Hirth; Hoon Kim; John Ralph; Claus Felby

2012-01-01

Solution-state two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy of plant cell walls is a powerful tool for characterizing changes in cell wall chemistry during the hydrothermal pretreatment process of wheat straw for second-generation bioethanol production. One-bond 13C-1H NMR correlation spectroscopy, via...

75 FR 42831 - Proposed Collection; Comment Request for Form 1065, Schedule C, Schedule D, Schedule K-1...

Science.gov (United States)

2010-07-22

.../or continuing information collections, as required by the Paperwork Reduction Act of 1995, Public Law... Income, Credits, Deductions and Other Items), Schedule L (Balance Sheets per Books), Schedule M-1 (Reconciliation of Income (Loss) per Books With Income (Loss) per Return)), Schedule M-2 (Analysis of Partners...

Geologic evolution of the Lost City Hydrothermal Field

Science.gov (United States)

Denny, Alden R.; Kelley, Deborah S.; Früh-Green, Gretchen L.

2016-02-01

The Lost City Hydrothermal Field (LCHF) is a novel serpentinite-hosted vent field located on the Atlantis Massif southern wall. Results of 2 m resolution bathymetry, side scan, and video and still imagery, integrated with direct submersible observations provide the first high-resolution geologic map of the LCHF. These data form the foundation for an evolutionary model for the vent system over the past >120,000 years. The field is located on a down-dropped bench 70 m below the summit of the massif. The bench is capped by breccia and pelagic carbonate deposits underlain by variably deformed and altered serpentinite and gabbroic rocks. Hydrothermal activity is focused at the 60 m tall, 100 m across, massive carbonate edifice "Poseidon," which is venting 91°C fluid. Hydrothermal activity declines south and west of the Poseidon complex and dies off completely at distances greater than 200 m. East of Poseidon, the most recent stage of hydrothermal flow is characterized by egress of diffuse fluids from narrow fissures within a low-angle, anastomosing mylonite zone. South of the area of current hydrothermal activity, there is evidence of two discrete previously unrecognized relict fields. Active venting sites defined by carbonate-filled fissures that cut the carbonate cap rock at the summit of the massif mark the present-day northernmost extent of venting. These spatial relationships reflect multiple stages of field development, the northward migration of venting over time, and the likely development of a nascent field at the massif summit.

Robust Optimization-Based Generation Self-Scheduling under Uncertain Price

Directory of Open Access Journals (Sweden)

Xiao Luo

2011-01-01

Full Text Available This paper considers generation self-scheduling in electricity markets under uncertain price. Based on the robust optimization (denoted as RO methodology, a new self-scheduling model, which has a complicated max-min optimization structure, is set up. By using optimal dual theory, the proposed model is reformulated to an ordinary quadratic and quadratic cone programming problems in the cases of box and ellipsoidal uncertainty, respectively. IEEE 30-bus system is used to test the new model. Some comparisons with other methods are done, and the sensitivity with respect to the uncertain set is analyzed. Comparing with the existed uncertain self-scheduling approaches, the new method has twofold characteristics. First, it does not need a prediction of distribution of random variables and just requires an estimated value and the uncertain set of power price. Second, the counterpart of RO corresponding to the self-scheduling is a simple quadratic or quadratic cone programming. This indicates that the reformulated problem can be solved by many ordinary optimization algorithms.

Distal transport of dissolved hydrothermal iron in the deep South Pacific Ocean.

Science.gov (United States)

Fitzsimmons, Jessica N; Boyle, Edward A; Jenkins, William J

2014-11-25

Until recently, hydrothermal vents were not considered to be an important source to the marine dissolved Fe (dFe) inventory because hydrothermal Fe was believed to precipitate quantitatively near the vent site. Based on recent abyssal dFe enrichments near hydrothermal vents, however, the leaky vent hypothesis [Toner BM, et al. (2012) Oceanography 25(1):209-212] argues that some hydrothermal Fe persists in the dissolved phase and contributes a significant flux of dFe to the global ocean. We show here the first, to our knowledge, dFe (Pacific Ocean, where dFe of 1.0-1.5 nmol/kg near 2,000 m depth (0.4-0.9 nmol/kg above typical deep-sea dFe concentrations) was determined to be hydrothermally derived based on its correlation with primordial (3)He and dissolved Mn (dFe:(3)He of 0.9-2.7 × 10(6)). Given the known sites of hydrothermal venting in these regions, this dFe must have been transported thousands of kilometers away from its vent site to reach our sampling stations. Additionally, changes in the size partitioning of the hydrothermal dFe between soluble (Pacific Rise only leaks 0.02-1% of total Fe vented into the abyssal Pacific, this dFe persists thousands of kilometers away from the vent source with sufficient magnitude that hydrothermal vents can have far-field effects on global dFe distributions and inventories (≥3% of global aerosol dFe input).

Hydrothermal systems on Mars: an assessment of present evidence

Science.gov (United States)

Farmer, J. D.

1996-01-01

Hydrothermal processes have been suggested to explain a number of observations for Mars, including D/H ratios of water extracted from Martian meteorites, as a means for removing CO2 from the Martian atmosphere and sequestering it in the crust as carbonates, and as a possible origin for iron oxide-rich spectral units on the floors of some rifted basins (chasmata). There are numerous examples of Martian channels formed by discharges of subsurface water near potential magmatic heat sources, and hydrothermal processes have also been proposed as a mechanism for aquifer recharge needed to sustain long term erosion of sapping channels. The following geological settings have been identified as targets for ancient hydrothermal systems on Mars: channels located along the margins of impact crater melt sheets and on the slopes of ancient volcanoes; chaotic and fretted terranes where shallow subsurface heat sources are thought to have interacted with ground ice; and the floors of calderas and rifted basins (e.g. chasmata). On Earth, such geological environments are often a locus for hydrothermal mineralization. But we presently lack the mineralogical information needed for a definitive evaluation of hypotheses. A preferred tool for identifying minerals by remote sensing methods on Earth is high spatial resolution, hyperspectral, near-infrared spectroscopy, a technique that has been extensively developed by mineral explorationists. Future efforts to explore Mars for ancient hydrothermal systems would benefit from the application of methods developed by the mining industry to look for similar deposits on Earth. But Earth-based exploration models must be adapted to account for the large differences in the climatic and geological history of Mars. For example, it is likely that the early surface environment of Mars was cool, perhaps consistently below freezing, with the shallow portions of hydrothermal systems being dominated by magma-cryosphere interactions. Given the smaller

Collaborative Distributed Scheduling Approaches for Wireless Sensor Network

Science.gov (United States)

Niu, Jianjun; Deng, Zhidong

2009-01-01

Energy constraints restrict the lifetime of wireless sensor networks (WSNs) with battery-powered nodes, which poses great challenges for their large scale application. In this paper, we propose a family of collaborative distributed scheduling approaches (CDSAs) based on the Markov process to reduce the energy consumption of a WSN. The family of CDSAs comprises of two approaches: a one-step collaborative distributed approach and a two-step collaborative distributed approach. The approaches enable nodes to learn the behavior information of its environment collaboratively and integrate sleep scheduling with transmission scheduling to reduce the energy consumption. We analyze the adaptability and practicality features of the CDSAs. The simulation results show that the two proposed approaches can effectively reduce nodes' energy consumption. Some other characteristics of the CDSAs like buffer occupation and packet delay are also analyzed in this paper. We evaluate CDSAs extensively on a 15-node WSN testbed. The test results show that the CDSAs conserve the energy effectively and are feasible for real WSNs. PMID:22408491

Sort-Mid tasks scheduling algorithm in grid computing.

Science.gov (United States)

Reda, Naglaa M; Tawfik, A; Marzok, Mohamed A; Khamis, Soheir M

2015-11-01

Scheduling tasks on heterogeneous resources distributed over a grid computing system is an NP-complete problem. The main aim for several researchers is to develop variant scheduling algorithms for achieving optimality, and they have shown a good performance for tasks scheduling regarding resources selection. However, using of the full power of resources is still a challenge. In this paper, a new heuristic algorithm called Sort-Mid is proposed. It aims to maximizing the utilization and minimizing the makespan. The new strategy of Sort-Mid algorithm is to find appropriate resources. The base step is to get the average value via sorting list of completion time of each task. Then, the maximum average is obtained. Finally, the task has the maximum average is allocated to the machine that has the minimum completion time. The allocated task is deleted and then, these steps are repeated until all tasks are allocated. Experimental tests show that the proposed algorithm outperforms almost other algorithms in terms of resources utilization and makespan.

Analysis of Issues for Project Scheduling by Multiple, Dispersed Schedulers (distributed Scheduling) and Requirements for Manual Protocols and Computer-based Support

Science.gov (United States)

Richards, Stephen F.

1991-01-01

Although computerized operations have significant gains realized in many areas, one area, scheduling, has enjoyed few benefits from automation. The traditional methods of industrial engineering and operations research have not proven robust enough to handle the complexities associated with the scheduling of realistic problems. To address this need, NASA has developed the computer-aided scheduling system (COMPASS), a sophisticated, interactive scheduling tool that is in wide-spread use within NASA and the contractor community. Therefore, COMPASS provides no explicit support for the large class of problems in which several people, perhaps at various locations, build separate schedules that share a common pool of resources. This research examines the issue of distributing scheduling, as applied to application domains characterized by the partial ordering of tasks, limited resources, and time restrictions. The focus of this research is on identifying issues related to distributed scheduling, locating applicable problem domains within NASA, and suggesting areas for ongoing research. The issues that this research identifies are goals, rescheduling requirements, database support, the need for communication and coordination among individual schedulers, the potential for expert system support for scheduling, and the possibility of integrating artificially intelligent schedulers into a network of human schedulers.

Additive effects of acetic acid upon hydrothermal reaction of amylopectin

International Nuclear Information System (INIS)

Sugano, Motoyuki; Katoh, Harumi; Komatsu, Akihiro; Kobayashi, Hiroshi; Okado, Kohta; Kakuta, Yusuke; Hirano, Katsumi

2012-01-01

It is well known that over 0.8 kg kg −1 of starch is consisted of amylopectin (AP). In this study, production of glucose for raw material of ethanol by hydrothermal reaction of AP as one of the model compound of food is discussed. Further, additive effects of acetic acid upon hydrothermal reactions of AP are also investigated. During hydrothermal reaction of AP, production of glucose occurred above 453 K, and the glucose yield increased to 0.48 kg kg −1 at 473 K. Upon hydrothermal reaction of AP at 473 K, prolongation of the holding time was not effective for the increase of the glucose yield. Upon hydrothermal reaction of AP at 473 K for 0 s, the glucose yield increased significantly by addition between 0.26 mol L −1 and 0.52 mol L −1 of acetic acid. However, the glucose yield decreased and the yield of the other constituents increased with the increases of concentration of acetic acid from 0.65 mol L −1 to 3.33 mol L −1 . It was considered that hydrolysis of AP to yield glucose was enhanced due to the increase of the amount of proton derived from acetic acid during hydrothermal reaction with 0.52 mol L −1 of acetic acid. -- Highlights: ► Glucose production by hydrothermal reaction of amylopectin (AP) at 473 K. ► Glucose yield increased to 0.48 kg kg -1 at 473 K. ► Prolongation of holding time was not effective for glucose yield. ► Glucose yield increased significantly by acetic acid (0.26–0.52 mol L-1) addition. ► Hydrolysis of AP to glucose was enhanced due to increase of proton from acetic acid.

Optimal distribution of reactivity excess in a system of reactors operating at a variable loading schedule

International Nuclear Information System (INIS)

Bolsunov, A.A.; Zagrebaev, A.M.; Naumov, V.I.

1979-01-01

Considered is the task of reactivity excess distribution optimization in the system of reactors for the purpose of minimazing the summary power production losses at the fixed loading schedule. Mathematical formulation of the task is presented. Given are the curves, characterizing the dependence of possible degree of the reactor power drop on reactivity excees for non-stationary Xe poisoning at different nominal density of neutron flux. Analyzing the results, it is concluded that in case, when the reactors differ only in neutron flux density the reactor with lower neutron flux density should be involved in the variable operation schedule first as the poisoning of this reactor will be less, and therefore, the losses of the system power production will be less. It is advisable to reserve the reactivity excess in the reactor with greater power or in the reactor with higher burnup rate. It is stressed that the obtained results of the optimization task solution point out the possibility of obtaining the certain ecomonic effect and permit to correct the requirements on mobility of separate power units at system approach to NPP operation in a variable loading schedule

Hydrothermal processing of transuranic contaminated combustible waste

International Nuclear Information System (INIS)

Buelow, S.J.; Worl, L.; Harradine, D.; Padilla, D.; McInroy, R.

2001-01-01

Experiments at Los Alamos National Laboratory have demonstrated the usefulness of hydrothermal processing for the disposal of a wide variety of transuranic contaminated combustible wastes. This paper provides an overview of the implementation and performance of hydrothermal treatment for concentrated salt solutions, explosives, propellants, organic solvents, halogenated solvents, and laboratory trash, such as paper and plastics. Reaction conditions vary from near ambient temperatures and pressure to over 1000degC and 100 MPa pressure. Studies involving both radioactive and non-radioactive waste simulants are discussed. (author)

Dynamic Hierarchical Sleep Scheduling for Wireless Ad-Hoc Sensor Networks

Directory of Open Access Journals (Sweden)

Chih-Yu Wen

2009-05-01

Full Text Available This paper presents two scheduling management schemes for wireless sensor networks, which manage the sensors by utilizing the hierarchical network structure and allocate network resources efficiently. A local criterion is used to simultaneously establish the sensing coverage and connectivity such that dynamic cluster-based sleep scheduling can be achieved. The proposed schemes are simulated and analyzed to abstract the network behaviors in a number of settings. The experimental results show that the proposed algorithms provide efficient network power control and can achieve high scalability in wireless sensor networks.

Dynamic hierarchical sleep scheduling for wireless ad-hoc sensor networks.

Science.gov (United States)

Wen, Chih-Yu; Chen, Ying-Chih

2009-01-01

This paper presents two scheduling management schemes for wireless sensor networks, which manage the sensors by utilizing the hierarchical network structure and allocate network resources efficiently. A local criterion is used to simultaneously establish the sensing coverage and connectivity such that dynamic cluster-based sleep scheduling can be achieved. The proposed schemes are simulated and analyzed to abstract the network behaviors in a number of settings. The experimental results show that the proposed algorithms provide efficient network power control and can achieve high scalability in wireless sensor networks.

Simulating Electrochemistry of Hydrothermal Vents on Enceladus and Other Ocean Worlds

Science.gov (United States)

Barge, L. M.; Krause, F. C.; Jones, J. P.; Billings, K.; Sobron, P.

2017-12-01

Gradients generated in hydrothermal systems provide a significant source of free energy for chemosynthetic life, and may play a role in present-day habitability on ocean worlds such as Enceladus that are thought to host hydrothermal activity. Hydrothermal vents are similar in some ways to typical fuel cell devices: redox/pH gradients between seawater and hydrothermal fluid are analogous to the oxidant and fuel reservoirs; conductive natural mineral deposits are analogous to electrodes; and, in hydrothermal chimneys, the porous chimney wall can function as a separator or ion-exchange membrane. Electrochemistry, founded on quantitative study of redox and other chemical disequilibria as well as the chemistry of interfaces, is uniquely suited to studying these systems. We have performed electrochemical studies to better understand the catalytic potential of seafloor minerals and vent chimneys, using samples from a black smoker vent chimney as an initial demonstration. Fuel cell experiments with electrodes made from black smoker chimney material accurately simulated the redox reactions that occur in a geological setting with this particular catalyst. Similar methods with other geo-catalysts (natural or synthetic) could be utilized to test which redox reactions or metabolisms could be driven in other hydrothermal systems, including putative vent systems on other worlds.

Accelerating exact schedulability analysis for fixed-priority pre-emptive scheduling

NARCIS (Netherlands)

Hang, Y.; Jiale, Z.; Keskin, U.; Bril, R.J.

2010-01-01

The schedulability analysis for fixed-priority preemptive scheduling (FPPS) plays a significant role in the real-time systems domain. The so-called Hyperplanes Exact Test (HET) [1] is an example of an exact schedulability test for FPPS. In this paper, we aim at improving the efficiency of HET by

Elemental geochemical records of seafloor hydrothermal activities in the sediments from the Okinawa Trough

Institute of Scientific and Technical Information of China (English)

ZHAI Shikui; YU Zenghui; DU Tongjun

2007-01-01

The major and minor element contents in the sediment core H9 from the hydrothermal fields of the Okinawa Trough show a sharp change at the depth of 80 cm. The elements enriched in the upper 80 cm core are those enriched in the hydrothermal deposits and in the surface sediments recovered from the hydrothermal fields in the trough, which indicates the input of hydrothermal materials. Comparing with other hydrothermal sediments from Mid-ocean Ridges or the Lau Basin, the degree of the enrichment of elements iron, copper, cobalt, and nickel is relatively low. However, the enrichment of elements manganese, lead, arsenic, antimony and mercury is remarkable. The average contents of these elements in the upper 80 cm core sediments are three to six times those in the lower section, and 3 ~ 12 times those in the surface sediments which are not influenced by hydrothermal activities. Hydrothermal activities have contributed significant manganese, lead, arsenic, antimony and mercury to the sediments, and these elements are distinct indicators for the hydrothermal activity in the Okinawa Trough. The significant enrichment of these elements in Core H9 upward from the depth 80 cm indicates the start or the significant enhancing of the hydrothermal activity in this area at about 5 740 aB. P. The average accumulation rate of manganese during this period is about 40 461 μg/( cm2 · ka), which is similar to the hydrothermal sediments in the Lau Basin or the East Pacific Rise.

Numerical Simulation of a Non-volcanic Hydrothermal System Caused by Formation of a High Permeability Fracture Zone

Science.gov (United States)

Oka, Daisuke; Ehara, Sachio; Fujimitsu, Yasuhiro

2010-05-01

Because in the Japanese islands the earth crust activity is very active, a disposal stratum for high-level radioactive waste produced by reprocessing the spent nuclear fuel from nuclear power plants will be selected in the tectonically stable areas in which the waste can be disposed underground safely for a long term and there is no influence of earthquakes, seismic activities, volcanic activities, upheaval, sedimentation, erosion, climate and global sea level change and so on, which causes the risk of the inflow of the groundwater to destroy the disposal site or the outflow to the ground surface. However, even if the disposal stratum in such condition will be chosen, in case that a new high permeability fracture zone is formed by the earthquake, and a new hydrothermal system may be formed for a long term (thousands or millions years) and the system may affect the disposal site. Therefore, we have to understand the feature of the non-volcanic hydrothermal system through the high permeability fracture zone. We estimated such influence by using HYDROTHERM Ver2.2 (Hayba & Ingebritsen, 1994), which is a three-dimensional numerical reservoir simulator. The model field is the northwestern part of Kego Fault, which was formed by a series of earthquakes called "the 2005 Fukuoka Prefecture Western Offshore Earthquakes" (the main shock of Mjma 7.0 on 20 March 2005) in Kyushu, Japan. The results of the numerical simulations show the development of a low temperature hydrothermal system as a new fracture zone is formed, in case that there is no volcanic heat source. The results of the simulations up to 100,000 years after formation of the fracture zone show that the higher heat flow and the wider and more permeable fracture zone accelerate the development of the hydrothermal system in the fracture zone. As a result of calculation of up to10 million years, we clarified the evolutional process of the non-volcanic hydrothermal system through the high permeability fracture zone. At

Sharing Data for Production Scheduling Using the ISA-95 Standard

Energy Technology Data Exchange (ETDEWEB)

Harjunkoski, Iiro, E-mail: iiro.harjunkoski@de.abb.com; Bauer, Reinhard [ABB Corporate Research, Industrial Software and Applications, Ladenburg (Germany)

2014-10-21

In the development and deployment of production scheduling solutions, one major challenge is to establish efficient information sharing with industrial production management systems. Information comprising production orders to be scheduled, processing plant structure, product recipes, available equipment, and other resources are necessary for producing a realistic short-term production plan. Currently, a widely accepted standard for information sharing is missing. This often leads to the implementation of costly custom-tailored interfaces, or in the worst case the scheduling solution will be abandoned. Additionally, it becomes difficult to easily compare different methods on various problem instances, which complicates the re-use of existing scheduling solutions. In order to overcome these hurdles, a platform-independent and holistic approach is needed. Nevertheless, it is difficult for any new solution to gain wide acceptance within industry as new standards are often refused by companies already using a different established interface. From an acceptance point of view, the ISA-95 standard could act as a neutral data-exchange platform. In this paper, we assess if this already widespread standard is simple, yet powerful enough to act as the desired holistic data exchange for scheduling solutions.

Sharing Data for Production Scheduling Using the ISA-95 Standard

International Nuclear Information System (INIS)

Harjunkoski, Iiro; Bauer, Reinhard

2014-01-01

In the development and deployment of production scheduling solutions, one major challenge is to establish efficient information sharing with industrial production management systems. Information comprising production orders to be scheduled, processing plant structure, product recipes, available equipment, and other resources are necessary for producing a realistic short-term production plan. Currently, a widely accepted standard for information sharing is missing. This often leads to the implementation of costly custom-tailored interfaces, or in the worst case the scheduling solution will be abandoned. Additionally, it becomes difficult to easily compare different methods on various problem instances, which complicates the re-use of existing scheduling solutions. In order to overcome these hurdles, a platform-independent and holistic approach is needed. Nevertheless, it is difficult for any new solution to gain wide acceptance within industry as new standards are often refused by companies already using a different established interface. From an acceptance point of view, the ISA-95 standard could act as a neutral data-exchange platform. In this paper, we assess if this already widespread standard is simple, yet powerful enough to act as the desired holistic data exchange for scheduling solutions.

Sharing data for production scheduling using the ISA-95 standard

Directory of Open Access Journals (Sweden)

Iiro eHarjunkoski

2014-10-01

Full Text Available In the development and deployment of production scheduling solutions one major challenge is to establish efficient information sharing with industrial production management systems. Information comprising production orders to be scheduled, processing plant structure, product recipes, available equipment and other resources are necessary for producing a realistic short-term production plan. Currently, a widely-accepted standard for information sharing is missing. This often leads to the implementation of costly custom-tailored interfaces, or in the worst case the scheduling solution will be abandoned. Additionally, it becomes difficult to easily compare different methods on various problem instances, which complicates the re-use of existing scheduling solutions. In order to overcome these hurdles, a platform-independent and holistic approach is needed. Nevertheless, it is difficult for any new solution to gain wide acceptance within industry as new standards are often refused by companies already using a different established interface. From an acceptance point of view, the ISA-95 standard could act as a neutral data-exchange platform. In this paper, we assess if this already widespread standard is simple, yet powerful enough to act as the desired holistic data-exchange for scheduling solutions.

Comparative study on microwave and conventional hydrothermal pretreatment of bamboo sawdust: Hydrochar properties and its pyrolysis behaviors

International Nuclear Information System (INIS)

Dai, Leilei; He, Chao; Wang, Yunpu; Liu, Yuhuan; Yu, Zhenting; Zhou, Yue; Fan, Liangliang; Duan, Dengle

2017-01-01

Highlights: • Two pretreatments affect differently the hydrochar properties and its pyrolysis behaviors. • Hydrochar by conventional hydrothermal pretreatment shows higher thermal stability. • Microwave hydrothermal pretreatment removes more acetyl. • Hydrochar by microwave hydrothermal pretreatment produces more glucopyranose and less acids. - Abstract: Comparative study on microwave and conventional hydrothermal pretreatment of bamboo sawdust was carried out in this study. Microwave and conventional hydrothermal pretreatment both improved the hydrochar properties and its pyrolysis behaviors. Proximate and elemental analyses show that the properties of hydrochar from microwave hydrothermal pretreatment are better than conventional hydrothermal pretreatment in terms of calorific value and oxygen content except for 150 °C. Microwave hydrothermal pretreatment removes more acetyl groups in hemicellulose compared to conventional hydrothermal pretreatment, which may be attributed to the hot spot effect of microwave irradiation. The peaks of thermogravimetric and derivative thermogravimetric curves of pretreated samples always shifted to higher temperature region. Also, the conventional hydrothermal pretreated samples are more thermally stable than those by microwave heating. In addition, the glucopyranose content in pyrolysis vapors of microwave hydrothermal pretreated bamboo sawdust (190 °C) was 9.82% higher than that from conventional hydrothermal pretreated bamboo sawdust. However, the acids content from microwave hydrothermal pretreated bamboo sawdust (150 °C) was 4.12% lower. In this regard, microwave hydrothermal pretreatment is more suitable for upgrading the pyrolysis oil quality than conventional hydrothermal pretreatment.

A multi-objective optimization of the active and reactive resource scheduling at a distribution level in a smart grid context

DEFF Research Database (Denmark)

Sousa, Tiago; Morais, Hugo; Vale, Zita

2015-01-01

In the traditional paradigm, the large power plants supply the reactive power required at a transmission level and the capacitors and transformer tap changer were also used at a distribution level. However, in a near future will be necessary to schedule both active and reactive power...... at a distribution level, due to the high number of resources connected in distribution levels. This paper proposes a new multi-objective methodology to deal with the optimal resource scheduling considering the distributed generation, electric vehicles and capacitor banks for the joint active and reactive power...... scheduling. The proposed methodology considers the minimization of the cost (economic perspective) of all distributed resources, and the minimization of the voltage magnitude difference (technical perspective) in all buses. The Pareto front is determined and a fuzzy-based mechanism is applied to present...

A Two-Stage Stochastic Mixed-Integer Programming Approach to the Smart House Scheduling Problem

Science.gov (United States)

Ozoe, Shunsuke; Tanaka, Yoichi; Fukushima, Masao

A “Smart House” is a highly energy-optimized house equipped with photovoltaic systems (PV systems), electric battery systems, fuel cell cogeneration systems (FC systems), electric vehicles (EVs) and so on. Smart houses are attracting much attention recently thanks to their enhanced ability to save energy by making full use of renewable energy and by achieving power grid stability despite an increased power draw for installed PV systems. Yet running a smart house's power system, with its multiple power sources and power storages, is no simple task. In this paper, we consider the problem of power scheduling for a smart house with a PV system, an FC system and an EV. We formulate the problem as a mixed integer programming problem, and then extend it to a stochastic programming problem involving recourse costs to cope with uncertain electricity demand, heat demand and PV power generation. Using our method, we seek to achieve the optimal power schedule running at the minimum expected operation cost. We present some results of numerical experiments with data on real-life demands and PV power generation to show the effectiveness of our method.

Hydrothermal Synthesis of Analcime from Kutingkeng Formation Mudstone

Science.gov (United States)

Hsiao, Yin-Hsiu; Chen, Kuan-Ting; Ray, Dah-Tong

2015-04-01

In southwest of Taiwan, the foothill located in Tainan-Kaohsiung city is the exposed area of Pliocene strata to early Pleistocene strata. The strata are about a depth of five thousand, named as Kutigkeng Formation. The outcrop of Kutigkeng Formation is typical badlands, specifically called 'Moon World.' It is commonly known as no important economic applications of agricultural land. The mineral compositions of Kutingkeng Formation are quartz, clay minerals and feldspar. The clay minerals consist of illite, clinochlore and swelling clays. To study how the phase and morphology of analcime formed by hydrothermal synthesis were affected, analcime was synthesized from the mudstone of Kutinkeng Formation with microwave hydrothermal reaction was investigated. The parameters of the experiment were the reaction temperature, the concentration of mineralizer, solids/liquid ratio and time. The sodium silicate (Na2SiO3) were used as mineralizer. The results showed that the analcime could be synthesized by hydrothermal reaction above 180° from Kutinkeng Formation mudstone samples. At the highest temperature (240°) of this study, the high purity analcime could be produced. When the concentration of Na2SiO3=3~6M, analcime could be synthesized at 240°. The best solids/liquid ratio was approximate 1 to 5. The hydrothermal reaction almost was completed after 4 hours.

Effects of hydrothermal post-treatment on microstructures and morphology of titanate nanoribbons

International Nuclear Information System (INIS)

Yu Huogen; Yu Jiaguo; Cheng Bei; Zhou Minghua

2006-01-01

Titanate nanoribbons were prepared via a hydrothermal treatment of rutile-type TiO 2 powders in a 10 M NaOH solution at 200 deg. C for 48 h. The as-prepared titanate nanoribbons were then hydrothermally post-treated at 150 deg. C for 12-36 h. The titanate nanoribbons before and after hydrothermal post-treatment were characterized with FESEM, XRD, TEM, UV-VIS and nitrogen adsorption-desorption isotherms. The results showed that the hydrothermal post-treatment not only promoted the phase transformation from titanate to anatase TiO 2 , but also was beneficial to the removal of Na + ions remained in the titanate nanoribbons. After hydrothermal post-treatment, the TiO 2 samples retained the one-dimensional structure feature of the titanate nanoribbons and showed an obvious increase in the specific surface area and the pore volume

Hydrothermal Processes in the Archean - New Insights from Imaging Spectroscopy

NARCIS (Netherlands)

Ruitenbeek, F.J.A. van

2007-01-01

The aim of this research was to gain new insights in fossil hydrothermal systems using airborne imaging spectroscopy. Fossil submarine hydrothermal systems in Archean greenstone belts and other geologic terranes are important because of their relationship with volcanic massive sulfide (VMS) mineral

Vein networks in hydrothermal systems provide constraints for the monitoring of active volcanoes.

Science.gov (United States)

Cucci, Luigi; Di Luccio, Francesca; Esposito, Alessandra; Ventura, Guido

2017-03-10

Vein networks affect the hydrothermal systems of many volcanoes, and variations in their arrangement may precede hydrothermal and volcanic eruptions. However, the long-term evolution of vein networks is often unknown because data are lacking. We analyze two gypsum-filled vein networks affecting the hydrothermal field of the active Lipari volcanic Island (Italy) to reconstruct the dynamics of the hydrothermal processes. The older network (E1) consists of sub-vertical, N-S striking veins; the younger network (E2) consists of veins without a preferred strike and dip. E2 veins have larger aperture/length, fracture density, dilatancy, and finite extension than E1. The fluid overpressure of E2 is larger than that of E1 veins, whereas the hydraulic conductance is lower. The larger number of fracture intersections in E2 slows down the fluid movement, and favors fluid interference effects and pressurization. Depths of the E1 and E2 hydrothermal sources are 0.8 km and 4.6 km, respectively. The decrease in the fluid flux, depth of the hydrothermal source, and the pressurization increase in E2 are likely associated to a magma reservoir. The decrease of fluid discharge in hydrothermal fields may reflect pressurization at depth potentially preceding hydrothermal explosions. This has significant implications for the long-term monitoring strategy of volcanoes.

Chemistry of a serpentinization-controlled hydrothermal system at the Lost City hydrothermal vent field

Science.gov (United States)

Ludwig, K. A.; Kelley, D. S.; Butterfield, D. A.; Nelson, B. K.; Karson, J. A.

2003-12-01

The Lost City Hydrothermal Field (LCHF), at 30° N near the Mid-Atlantic Ridge, is an off-axis, low temperature, high-pH, ultramafic-hosted vent system. Within the field, carbonate chimneys tower up to 60 m above the seafloor, making them the tallest vent structures known. The chemistry of the vent structures and fluids at the LCHF is controlled by reactions between seawater and ultramafic rocks beneath the Atlantis massif. Mixing of warm alkaline vent fluids with seawater causes precipitation of calcium carbonate and growth of the edifaces, which range from tall, graceful pinnacles to fragile flanges and colloform deposits. Geochemical and petrological analyses of the carbonate rocks reveal distinct differences between the active and extinct structures. Actively venting chimneys and flanges are extremely porous, friable formations composed predominantly of aragonite and brucite. These structures provide important niches for well-developed microbial communities that thrive on and within the chimney walls. Some of the active chimneys may also contain the mineral ikaite, an unstable, hydrated form of calcium carbonate. TIMS and ICP-MS analyses of the carbonate chimneys show that the most active chimneys have low Sr isotope values and that they are low in trace metals (e.g., Mn, Ti, Pb). Active structures emit high-pH, low-Mg fluids at 40-90° C. The fluids also have low Sr values, indicating circulation of hydrothermal solutions through the serpentinite bedrock beneath the field. In contrast to the active structures, extinct chimneys are less porous, are well lithified, and they are composed predominantly of calcite that yields Sr isotopes near seawater values. Prolonged lower temperature seawater-hydrothermal fluid interaction within the chimneys results in the conversion of aragonite to calcite and in the enrichment of some trace metals (e.g., Mn, Ti, Co, Zn). It also promotes the incorporation of foraminifera within the outer, cemented walls of the carbonate

Generalized gain scheduling for deloaded wind turbine operation

DEFF Research Database (Denmark)

Venne, Philippe; Guillaud, X.; Teodorescu, Remus

2010-01-01

to regulate both power production and rotor speed under any wind speed conditions. In this paper, a novel controller for deloaded wind turbine operation is presented. This controller is made possible by a Cp table inversion procedure allowing generalized gain scheduling for linearization of the pitch response......The ability to produce less power than what is available from a wind source, a condition known as deloaded operation, is needed for a wind turbine to reproduce synchronous machine behavior in terms of inertial response and frequency droop regulation. Deloaded operation requires the ability...

Spatial Distribution of Viruses Associated with Planktonic and Attached Microbial Communities in Hydrothermal Environments

Science.gov (United States)

Nunoura, Takuro; Kazama, Hiromi; Noguchi, Takuroh; Inoue, Kazuhiro; Akashi, Hironori; Yamanaka, Toshiro; Toki, Tomohiro; Yamamoto, Masahiro; Furushima, Yasuo; Ueno, Yuichiro; Yamamoto, Hiroyuki; Takai, Ken

2012-01-01

Viruses play important roles in marine surface ecosystems, but little is known about viral ecology and virus-mediated processes in deep-sea hydrothermal microbial communities. In this study, we examined virus-like particle (VLP) abundances in planktonic and attached microbial communities, which occur in physical and chemical gradients in both deep and shallow submarine hydrothermal environments (mixing waters between hydrothermal fluids and ambient seawater and dense microbial communities attached to chimney surface areas or macrofaunal bodies and colonies). We found that viruses were widely distributed in a variety of hydrothermal microbial habitats, with the exception of the interior parts of hydrothermal chimney structures. The VLP abundance and VLP-to-prokaryote ratio (VPR) in the planktonic habitats increased as the ratio of hydrothermal fluid to mixing water increased. On the other hand, the VLP abundance in attached microbial communities was significantly and positively correlated with the whole prokaryotic abundance; however, the VPRs were always much lower than those for the surrounding hydrothermal waters. This is the first report to show VLP abundance in the attached microbial communities of submarine hydrothermal environments, which presented VPR values significantly lower than those in planktonic microbial communities reported before. These results suggested that viral lifestyles (e.g., lysogenic prevalence) and virus interactions with prokaryotes are significantly different among the planktonic and attached microbial communities that are developing in the submarine hydrothermal environments. PMID:22210205

Duration of hydrothermal treatment and peeling of 'Murcott' tangor

Directory of Open Access Journals (Sweden)

Ana Luiza Pinheiro

2011-12-01

Full Text Available Hydrothermal treatment facilitates the peeling of 'Pera' sweet orange fruit and does not alter its quality. The aim of this work was to adapt the technology of peeling for the use of hydrothermal treatment in 'Murcott' tangor and to evaluate its influence in the CO2 production and the physicochemical, microbiologic and sensorial characteristics of fruits. The peeling time, the yield of marketable fruits and the internal temperature of fruits during the treatment were also evaluated. The hydrothermal treatment consisted of placing the fruits in a water-bath at 50 ºC for 5, 10, 15, 20, 25 and 30 min. Fruits were peeled by first opening a gap in the peduncle region with a knife and then manually removing the flavedo and albedo. Fruits were stored at 5 ºC for six days. Hydrothermal treatment caused changes in the fruits' CO2 production for only the first few hours after processing. Internal fruit temperature after 30 min of treatment reached 35 ºC. There were no changes in the physicochemical and microbiologic characteristics of the fruits. The treatment did not change the flavor, improved the fruits' appearance, decreased the peeling time of the treated fruits by 57 % and increased the yield of marketable fruits. In conclusion, the hydrothermal treatment accomplished from 5 to 30 min at 50 ºC can be used as part of the peeling process for 'Murcott' tangor.

Microgrid optimal scheduling considering impact of high penetration wind generation

Science.gov (United States)

Alanazi, Abdulaziz

The objective of this thesis is to study the impact of high penetration wind energy in economic and reliable operation of microgrids. Wind power is variable, i.e., constantly changing, and nondispatchable, i.e., cannot be controlled by the microgrid controller. Thus an accurate forecasting of wind power is an essential task in order to study its impacts in microgrid operation. Two commonly used forecasting methods including Autoregressive Integrated Moving Average (ARIMA) and Artificial Neural Network (ANN) have been used in this thesis to improve the wind power forecasting. The forecasting error is calculated using a Mean Absolute Percentage Error (MAPE) and is improved using the ANN. The wind forecast is further used in the microgrid optimal scheduling problem. The microgrid optimal scheduling is performed by developing a viable model for security-constrained unit commitment (SCUC) based on mixed-integer linear programing (MILP) method. The proposed SCUC is solved for various wind penetration levels and the relationship between the total cost and the wind power penetration is found. In order to reduce microgrid power transfer fluctuations, an additional constraint is proposed and added to the SCUC formulation. The new constraint would control the time-based fluctuations. The impact of the constraint on microgrid SCUC results is tested and validated with numerical analysis. Finally, the applicability of proposed models is demonstrated through numerical simulations.

Kinetics of the hydrothermal treatment of tannin for producing carbonaceous microspheres.

Science.gov (United States)

Braghiroli, F L; Fierro, V; Izquierdo, M T; Parmentier, J; Pizzi, A; Celzard, A

2014-01-01

Aqueous solutions of condensed tannins were submitted to hydrothermal carbonization (HTC) in a stainless steel autoclave, and the kinetics of hydrothermal carbon formation was investigated by changing several parameters: amount of tannin (0.5; 1.0; 1.5; 2.0 g in 16 mL of water), HTC temperature (130, 160, 180 and 200°C) and reaction times (from 1 to 720 h). The morphology and the structure of the tannin-based hydrothermal carbons were studied by TEM, krypton adsorption at -196°C and helium pycnometry. These materials presented agglomerated spherical particles, having surface areas ranging from 0.6 to 10.0 m(2) g(-1). The chemical composition of the hydrothermal carbons was found to be constant and independent of reaction time. HTC kinetics of tannin were determined and shown to correspond to first-order reaction. Temperature-dependent measurements led to an activation energy of 91 kJ mol(-1) for hydrothermal conversion of tannin into carbonaceous microspheres separable by centrifugation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Levulinic acid from orange peel waste by hydrothermal carbonization (HTC)

NARCIS (Netherlands)

Puccini, Monica; Licursi, Domenico; Stefanelli, Eleonora; Vitolo, Sandra; Galletti, Anna Maria Raspolli; Heeres, Hero Jan

2016-01-01

With the awareness of the need for optimal and sustainable use of natural resources, hydrothermal treatment of biomass and biomass waste for energy and resource recovery has received increasing attention. The hydrothermal carbonization (HTC) of a biomass is achieved using water as the reaction

Web Publishing Schedule

Science.gov (United States)

Section 207(f)(2) of the E-Gov Act requires federal agencies to develop an inventory and establish a schedule of information to be published on their Web sites, make those schedules available for public comment. To post the schedules on the web site.

Understanding the Compositional Variability of the Major Components of Hydrothermal Plumes in the Okinawa Trough

Directory of Open Access Journals (Sweden)

Zhigang Zeng

2018-01-01

Full Text Available Studies of the major components of hydrothermal plumes in seafloor hydrothermal fields are critical for an improved understanding of biogeochemical cycles and the large-scale distribution of elements in the submarine environment. The composition of major components in hydrothermal plume water column samples from 25 stations has been investigated in the middle and southern Okinawa Trough. The physical and chemical properties of hydrothermal plume water in the Okinawa Trough have been affected by input of the Kuroshio current, and its influence on hydrothermal plume water from the southern Okinawa Trough to the middle Okinawa Trough is reduced. The anomalous layers of seawater in the hydrothermal plume water columns have higher K+, Ca2+, Mn2+, B3+, Ca2+/SO42-, and Mn2+/Mg2+ ratios and higher optical anomalies than other layers. The Mg2+, SO42-, Mg2+/Ca2+, and SO42-/Mn2+ ratios of the anomalous layers are lower than other layers in the hydrothermal plume water columns and are consistent with concentrations in hydrothermal vent fluids in the Okinawa Trough. This suggests that the chemical variations of hydrothermal plumes in the Tangyin hydrothermal field, like other hydrothermal fields, result in the discharge of high K+, Ca2+, and B3+ and low Mg2+ and SO42- fluid. Furthermore, element ratios (e.g., Sr2+/Ca2+, Ca2+/Cl− in hydrothermal plume water columns were found to be similar to those in average seawater, indicating that Sr2+/Ca2+ and Ca2+/Cl− ratios of hydrothermal plumes might be useful proxies for chemical properties of seawater. The hydrothermal K+, Ca2+, Mn2+, and B3+ flux to seawater in the Okinawa Trough is about 2.62–873, 1.04–326, 1.30–76.4, and 0.293–34.7 × 106 kg per year, respectively. The heat flux is about 0.159–1,973 × 105 W, which means that roughly 0.0006% of ocean heat is supplied by seafloor hydrothermal plumes in the Okinawa Trough.

Large-scale in situ heater tests for hydrothermal characterization at Yucca Mountain

International Nuclear Information System (INIS)

Buscheck, T.A.; Wilder, D.G.; Nitao, J.J.

1993-01-01

To safely and permanently store high-level nuclear-waste, the potential Yucca Mountain repository site must mitigate the release and transport of radionuclides for tens of thousands of years. In the failure scenario of greatest concern, water would contact a waste package, accelerate its failure rate, and eventually transport radionuclides to the water table. Our analysis indicate that the ambient hydrological system will be dominated by repository-heat-driven hydrothermal flow for tens of thousands of years. In situ heater tests are required to provide an understanding of coupled geomechanical-hydrothermal-geochemical behavior in the engineered and natural barriers under repository thermal loading conditions. In situ heater tests have been included in the Site Characterization Plan in response to regulatory requirements for site characterization and to support the validation of process models required to assess the total systems performance at the site. The success of the License Application (LA) hinges largely on how effectively we validate the process models that provide the basis for performance assessment. Because of limited time, some of the in situ tests will have to be accelerated relative to actual thermal loading conditions. We examine the trade-offs between the limited test duration and generating hydrothermal conditions applicable to repository performance during the entire thermal loading cycle, including heating (boiling and dry-out) and cooldown (re-wetting). For in situ heater tests duration of 6-7 yr (including 4 yr of full-power heating) is required. The parallel use of highly accelerated, shorter-duration tests may provide timely information for the LA, provided that the applicability of the test results can be validated against ongoing nominal-rate heater tests

Basin-scale transport of hydrothermal dissolved metals across the South Pacific Ocean.

Science.gov (United States)

Resing, Joseph A; Sedwick, Peter N; German, Christopher R; Jenkins, William J; Moffett, James W; Sohst, Bettina M; Tagliabue, Alessandro

2015-07-09

Hydrothermal venting along mid-ocean ridges exerts an important control on the chemical composition of sea water by serving as a major source or sink for a number of trace elements in the ocean. Of these, iron has received considerable attention because of its role as an essential and often limiting nutrient for primary production in regions of the ocean that are of critical importance for the global carbon cycle. It has been thought that most of the dissolved iron discharged by hydrothermal vents is lost from solution close to ridge-axis sources and is thus of limited importance for ocean biogeochemistry. This long-standing view is challenged by recent studies which suggest that stabilization of hydrothermal dissolved iron may facilitate its long-range oceanic transport. Such transport has been subsequently inferred from spatially limited oceanographic observations. Here we report data from the US GEOTRACES Eastern Pacific Zonal Transect (EPZT) that demonstrate lateral transport of hydrothermal dissolved iron, manganese, and aluminium from the southern East Pacific Rise (SEPR) several thousand kilometres westward across the South Pacific Ocean. Dissolved iron exhibits nearly conservative (that is, no loss from solution during transport and mixing) behaviour in this hydrothermal plume, implying a greater longevity in the deep ocean than previously assumed. Based on our observations, we estimate a global hydrothermal dissolved iron input of three to four gigamoles per year to the ocean interior, which is more than fourfold higher than previous estimates. Complementary simulations with a global-scale ocean biogeochemical model suggest that the observed transport of hydrothermal dissolved iron requires some means of physicochemical stabilization and indicate that hydrothermally derived iron sustains a large fraction of Southern Ocean export production.

SiC-dopped MCM-41 materials with enhanced thermal and hydrothermal stabilities

International Nuclear Information System (INIS)

Wang, Yingyong; Jin, Guoqiang; Tong, Xili; Guo, Xiangyun

2011-01-01

Graphical abstract: Novel SiC-dopped MCM-41 materials were synthesized by adding silicon carbide suspension in the molecular sieve precursor solvent followed by in situ hydrothermal synthesis. The dopped materials have a wormhole-like mesoporous structure and exhibit enhanced thermal and hydrothermal stabilities. Highlights: → SiC-dopped MCM-41 was synthesized by in situ hydrothermal synthesis of molecular sieve precursor combined with SiC. → The dopped MCM-41 materials show a wormhole-like mesoporous structure. → The thermal stability of the dopped materials have an increment of almost 100 o C compared with the pure MCM-41. → The hydrothermal stability of the dopped materials is also better than that of the pure MCM-41. -- Abstract: SiC-dopped MCM-41 mesoporous materials were synthesized by the in situ hydrothermal synthesis, in which a small amount of SiC was added in the precursor solvent of molecular sieve before the hydrothermal treatment. The materials were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, N 2 physical adsorption and thermogravimetric analysis, respectively. The results show that the thermal and hydrothermal stabilities of MCM-41 materials can be improved obviously by incorporating a small amount of SiC. The structure collapse temperature of SiC-dopped MCM-41 materials is 100 o C higher than that of pure MCM-41 according to the differential scanning calorimetry analysis. Hydrothermal treatment experiments also show that the pure MCM-41 will losses it's ordered mesoporous structure in boiling water for 24 h while the SiC-dopped MCM-41 materials still keep partial porous structure.

Preservation of iron(II) by carbon-rich matrices in a hydrothermal plume

Energy Technology Data Exchange (ETDEWEB)

Toner, Brandy M.; Fakra, Sirine C.; Manganini, Steven J.; Santelli, Cara M.; Marcus, Matthew A.; Moffett, James W.; Rouxel, Olivier; German, Christopher R.; Edwards, Katrina J.

2008-09-20

Hydrothermal venting associated with mid-ocean ridge volcanism is globally widespread. This venting is responsible for a dissolved iron flux to the ocean that is approximately equal to that associated with continental riverine runoff. For hydrothermal fluxes, it has long been assumed that most of the iron entering the oceans is precipitated in inorganic forms. However, the possibility of globally significant fluxes of iron escaping these mass precipitation events and entering open-ocean cycles is now being debated, and two recent studies suggest that dissolved organic ligands might influence the fate of hydrothermally vented metals. Here we present spectromicroscopic measurements of iron and carbon in hydrothermal plume particles at the East Pacific Rise mid-ocean ridge. We show that organic carbon-rich matrices, containing evenly dispersed iron(II)-rich materials, are pervasive in hydrothermal plume particles. The absence of discrete iron(II) particles suggests that the carbon and iron associate through sorption or complexation. We suggest that these carbon matrices stabilize iron(II) released from hydrothermal vents in the region, preventing its oxidation and/or precipitation as insoluble minerals. Our findings have implications for deep-sea biogeochemical cycling of iron, a widely recognized limiting nutrient in the oceans.

Effects of hydrothermal treatment of sewage sludge on pyrolysis and steam gasification

International Nuclear Information System (INIS)

Moon, Jihong; Mun, Tae-Young; Yang, Won; Lee, Uendo; Hwang, Jungho; Jang, Ensuk; Choi, Changsik

2015-01-01

Highlights: • Hydrothermal treatment (HT) is energy efficient and increases fuel energy density. • Pyrolysis and steam gasification were performed with sewage sludge before/after HT. • Product gases resembled those from wood chips, particularly at high temperature. • HT increases sludge lignin content, possibly enhancing methane yield of product gas. • HT can improve sewage sludge for use as an alternative to biomass and fossil fuels. - Abstract: Hydrothermal treatment is a promising option for pretreatment drying of organic waste, due to its low energy consumption and contribution to increasing fuel energy density. In this study, the characteristics of hydrothermally treated sewage sludge were investigated, and pyrolysis and steam gasification were performed with the sludge before and after hydrothermal treatment. The overall composition of product gases from treated sludge was similar to that obtained from steam gasification of wood chips, particularly under high-temperature conditions. In addition, the increase in lignin content of sewage sludge following hydrothermal treatment could help enhance methane yield in product gas during pyrolysis and steam gasification. The findings suggest that hydrothermal treatment is an appropriate method for improving sewage sludge for use as an alternative to biomass and fossil fuels

Technique-economic feasibility of improvements of the hydrothermal behavior of houses of social interest in the province of San Juan, Argentina; Factibilidad tecnica-economica de mejoras del comportamiento higrotermico de viviendas de interes social en la provincia de San Juan, Argentina

Energy Technology Data Exchange (ETDEWEB)

Girini, H. R.; Navas, R. F.; Romarion, R. R.; Girini, M. R.

2008-07-01

Applying software of hydrothermal atmosphere simulation, one looks for to evaluate technique and economically different changes from design that produce improvements of the hydrothermal behavior of houses of social interest, allowing to select the most advisable changes. To make small changes of design that mean improvements of the behavior and the power efficiency and to evaluate them technically and economically. Based on developments of own programs computer science in varied regime, that allow the weekly hydrothermal simulation, monthly and annual of the climate with the determination of the different heat flows from that and atmosphere as much in winter as in summer is put under. Results: Significant improvements in the power efficiency of houses can be obtained, with favorable economic indices and low initial investments. (Author)

Shift scheduling limits for the nuclear industry NRC policy and recommendations

International Nuclear Information System (INIS)

Koontz, J.; Morisseau, D.; Lewis, P.

1985-01-01

A study on shift scheduling and use of overtime and their effects on human performance in nuclear and non-nuclear industries was conducted. An analysis of the literature, current practices, and federal policy on shift scheduling resulted in human factors recommendations for limiting hours of work in the nuclear industry for nuclear power plant personnel conducting safety related functions. Recommended limits on total hours of work were developed by a panel of experts for both 8-hour and 12-hour daily shift schedules for weekly, biweekly, monthly, and annual work periods. The study results are particularly applicable to control room operators but should also be considered for other personnel where performance degradation due to fatigue could directly affect safe plant operations

Schedule Matters: Understanding the Relationship between Schedule Delays and Costs on Overruns

Science.gov (United States)

Majerowicz, Walt; Shinn, Stephen A.

2016-01-01

This paper examines the relationship between schedule delays and cost overruns on complex projects. It is generally accepted by many project practitioners that cost overruns are directly related to schedule delays. But what does "directly related to" actually mean? Some reasons or root causes for schedule delays and associated cost overruns are obvious, if only in hindsight. For example, unrealistic estimates, supply chain difficulties, insufficient schedule margin, technical problems, scope changes, or the occurrence of risk events can negatively impact schedule performance. Other factors driving schedule delays and cost overruns may be less obvious and more difficult to quantify. Examples of these less obvious factors include project complexity, flawed estimating assumptions, over-optimism, political factors, "black swan" events, or even poor leadership and communication. Indeed, is it even possible the schedule itself could be a source of delay and subsequent cost overrun? Through literature review, surveys of project practitioners, and the authors' own experience on NASA programs and projects, the authors will categorize and examine the various factors affecting the relationship between project schedule delays and cost growth. The authors will also propose some ideas for organizations to consider to help create an awareness of the factors which could cause or influence schedule delays and associated cost growth on complex projects.

Hydrothermal response to a volcano-tectonic earthquake swarm, Lassen, California

Science.gov (United States)

Ingebritsen, Steven E.; Shelly, David R.; Hsieh, Paul A.; Clor, Laura; P.H. Seward,; Evans, William C.

2015-01-01

The increasing capability of seismic, geodetic, and hydrothermal observation networks allows recognition of volcanic unrest that could previously have gone undetected, creating an imperative to diagnose and interpret unrest episodes. A November 2014 earthquake swarm near Lassen Volcanic National Park, California, which included the largest earthquake in the area in more than 60 years, was accompanied by a rarely observed outburst of hydrothermal fluids. Although the earthquake swarm likely reflects upward migration of endogenous H2O-CO2 fluids in the source region, there is no evidence that such fluids emerged at the surface. Instead, shaking from the modest sized (moment magnitude 3.85) but proximal earthquake caused near-vent permeability increases that triggered increased outflow of hydrothermal fluids already present and equilibrated in a local hydrothermal aquifer. Long-term, multiparametric monitoring at Lassen and other well-instrumented volcanoes enhances interpretation of unrest and can provide a basis for detailed physical modeling.

Subcritical hydrothermal conversion of organic wastes and biomass. Reaction pathways

Directory of Open Access Journals (Sweden)

Alejandro Amadeus Castro Vega

2007-01-01

Full Text Available Hydrothermal conversion is a procedure which emulates organic matter’s natural conversion into bio-crude having physical and chemical properties analogous to petroleum. The artificial transformation of biomass requi- res previous knowledge of the main reaction routes and product availability. The main component of biomass (depolymerisation by hydrolysis is presented in hydrothermal cellulose conversion, producing oligosaccharides which exhibit dehydration and retro-aldol condensation reactions for transforming into furfurals and carboxylic acids. Other biomass components (such as lignin, proteins, and fat esters present both hydrolysis and pyrolysis reaction routes. As long as biomass mainly contains carbohydrates, subcritical hydrothermal conversion products and their wastes will be fundamentally analogous to those displaying cellulose. These substances have added- value by far surpassing raw material’s acquisition cost. When the main hydrothermal conversion products’ O/C, H/C molar ratios as reported in literature are plotted, an evolutionary tralectory for conversion products appears to be closely or even overlapped with fossil fuels’ geological evolution.

Dynamic behavior of Kilauea Volcano and its relation to hydrothermal systems and geothermal energy

Science.gov (United States)

Kauhikaua, Jim; Moore, R.B.; ,

1993-01-01

Exploitation of hydrothermal systems on active basaltic volcanoes poses some unique questions about the role of volcanism and hydrothermal system evolution. Volcanic activity creates and maintains hydrothermal systems while earthquakes create permeable fractures that, at least temporarily, enhance circulation. Magma and water, possibly hydrothermal water, can interact violently to produce explosive eruptions. Finally, we speculate on whether volcanic behavior can be affected by high rates of heat extraction.

Hydrothermal metallurgy for recycling of slag and glass

International Nuclear Information System (INIS)

Tanaka, Toshihiro; Yoshikawa, Takeshi; Hirai, Nobumitsu; Katsuyama, Shigeru

2009-01-01

The authors have applied hydrothermal reactions to develop recycling processing of slag or glass. As an example, under hydrothermal conditions such as 200 300 deg. C and 30 40MPa with H 2 O, powders made of glass can be sintered to become solidified glass materials containing about 10mass% H 2 O. When the glass containing H 2 O is heated again under normal pressure, the glass expands releasing H 2 O to make porous microstructure. H 2 O starts to emit just above the glass transition temperature. Therefore, when we have a glass with low glass transition temperature, we can make low temperature foaming glass. The SiO 2 -Na 2 O-B 2 O 3 glass is a candidate to be such a foaming glass. In this paper, we describe our recent trial on the fabrication of the low temperature foaming glass by using hydrothermal reaction.

Effect of hydrothermal treatment on some properties of Shenhua coal

Energy Technology Data Exchange (ETDEWEB)

Wang Zhi-cai; Shui Heng-fu; Zhang De-xiang; Gao Jin-sheng [East China University of Science and Technology, Shanghai (China). College of Resource and Environmental Engineering

2006-10-15

Effects of hydrothermal treatment on swelling, extraction and liquefaction behavior of Shenhua coal were studied through analyses of element content, ash content, volatile content and IR spectrum of treated coal. The results indicate that hydrogenation of coal is distinctly carried out in the process of hydrothermal pre-treatment and the hydrogen content of treated coal is more than that of raw coal. The contents of ash and volatile matters of treated coal are lower than those of raw coal. With the increase of treatment temperature the volatile content of the hydrothermal treated coal decreases and the ash content of treated coal increases. CO{sub 2} is main gas product and unvaries with the temperature changing, whereas CO and CH{sub 4} are formed when the temperature is above 250{sup o}C and increase with the temperature during hydrothermal treatment. Hydrothermal treatment is not in favor of coal swelling and the swelling ratio of treated coal decreases with the increase of treatment temperature. The swelling ratio of extraction residue by CS{sub 2}/NMP mixed solvent in NMP solvent is lower than that of the corresponding raw coal. The CS{sub 2}/NMP mixed solvent extraction yields of coal treated at appropriate temperature are higher than that of raw coal, but the extraction yields of treated coal obtained by n-hexane, toluene and THF successive Soxhelt extraction are lower. Hydrothermal treatment at 250-300{sup o}C can increase the conversion of treated coal in direct hydro-liquefaction. The gas + oil yield of treated coal is lower than that of raw coal and the preasphaltene yield of treated coal is much higher. IR spectra of treated coals show that the forms of non-covalent bonds are changed by hydrothermal treatment, and the hydrolysis of ester and ether bonds and the pyrolysis of aromatic side chains also maybe occur at high treatment temperature. 21 refs., 3 figs., 4 tabs.

Hydrothermal synthesis, characterization and luminescent ...

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 39; Issue 4. Hydrothermal synthesis, characterization and luminescent properties of lanthanide-doped NaLaF 4 nanoparticles. JIGMET LADOL HEENA KHAJURIA SONIKA KHAJURIA ... Keywords. Citric acid; X-ray diffraction; down-conversion emission; energy transfer.

Electricity usage scheduling in smart building environments using smart devices.

Science.gov (United States)

Lee, Eunji; Bahn, Hyokyung

2013-01-01

With the recent advances in smart grid technologies as well as the increasing dissemination of smart meters, the electricity usage of every moment can be detected in modern smart building environments. Thus, the utility company adopts different price of electricity at each time slot considering the peak time. This paper presents a new electricity usage scheduling algorithm for smart buildings that adopts real-time pricing of electricity. The proposed algorithm detects the change of electricity prices by making use of a smart device and changes the power mode of each electric device dynamically. Specifically, we formulate the electricity usage scheduling problem as a real-time task scheduling problem and show that it is a complex search problem that has an exponential time complexity. An efficient heuristic based on genetic algorithms is performed on a smart device to cut down the huge searching space and find a reasonable schedule within a feasible time budget. Experimental results with various building conditions show that the proposed algorithm reduces the electricity charge of a smart building by 25.6% on average and up to 33.4%.

Organization of the construction and schedule of realization

International Nuclear Information System (INIS)

Szerovay, Antal; Vogel, Oszkar

1988-01-01

The four units of the Paks nuclear power plant with all the auxiliary and service facilities were constructed between 1974 and 1987. Major features of building activities, types of buildings classified according to the connection between the facility and the technology are listed. Processes and structures applied to the construction of the main reactor building are mentioned emphasizing the importance of up-to-date building methods. To move the large equipment into the reactor building Potain cranes of 400 Mp were used. As a result of adequate schedule the auxiliary buildings could be used as preparatory buildings during the construction of the plant. The energy and material supply, the schedule of the construction works are discussed. (V.N.) 6 refs.; 5 figs

Development of a compact nuclear power station engineering simulator

International Nuclear Information System (INIS)

Jian Jianfeng; Yang Yanhua; Lin Meng; Hu Rui

2003-01-01

The compact nuclear power plant project simulator is developed based on the Chashma nuclear power plant. This simulator consists of simulation computation code, data communication module and human-machine interface. This paper discusses the design and implementation of the simulator from such aspect as computer system, hydrothermal model, programming language, human-machine interface and data communication in details

Synthesis of ZrO2 nanoparticles by hydrothermal treatment

International Nuclear Information System (INIS)

Machmudah, Siti; Widiyastuti, W.; Prastuti, Okky Putri; Nurtono, Tantular; Winardi, Sugeng; Wahyudiono,; Kanda, Hideki; Goto, Motonobu

2014-01-01

Zirconium oxide (zirconia, ZrO 2 ) is the most common material used for electrolyte of solid oxide fuel cells (SOFCs). Zirconia has attracted attention for applications in optical coatings, buffer layers for growing superconductors, thermal-shield, corrosion resistant coatings, ionic conductors, and oxygen sensors, and for potential applications including transparent optical devices and electrochemical capacitor electrodes, fuel cells, catalysts, and advanced ceramics. In this work, zirconia particles were synthesized from ZrCl 4 precursor with hydrothermal treatment in a batch reactor. Hydrothermal treatment may allow obtaining nanoparticles and sintered materials with controlled chemical and structural characteristics. Hydrothermal treatment was carried out at temperatures of 150 – 200°C with precursor concentration of 0.1 – 0.5 M. Zirconia particles obtained from this treatment were analyzed by using SEM, PSD and XRD to characterize the morphology, particle size distribution, and crystallinity, respectively. Based on the analysis, the size of zirconia particles were around 200 nm and it became smaller with decreasing precursor concentration. The increasing temperature caused the particles formed having uniform size. Zirconia particles formed by hydrothermal treatment were monoclinic, tetragonal and cubic crystal

Multi-Channel Scheduling for Fast Convergecast in Wireless Sensor Networks

NARCIS (Netherlands)

Durmaz, O.; Ghosh, A.; Krishnamachari, B.; Chintalapudi, K.

We explore the following fundamental question - how fast can information be collected from a wireless sensor network? We consider a number of design parameters such as, power control, time and frequency scheduling, and routing. There are essentially two factors that hinder efficient data collection

Production of lightweight refractory material by hydrothermal process

International Nuclear Information System (INIS)

Sulejmani, Ramiz B.

2002-01-01

Many different processes of production of lightweight refractories are well known over the World. Traditional production of lightweight refractories is by addition of combustibles or by a special frothing process. This work is concerned with hydrothermal of lightweight refractories from rice husk ash. The rice husk ash, used in present investigations were from Kocani region, R. Macedonia. The chemical analysis of the rice husk ash shows that it contains 91,8 - 93,7% SiO 2 and some alkaline and alkaline earth oxides. Microscopic and X - ray diffraction examinations of the rice husk ash have shown that it is composed of cristobalite, tridimite and amorphous silica. The composition of the mixture for lightweight refractory brick production is 93,4% rice husk ash and 6,6% Ca(OH) 2 . The mixtures were well mixed, moistened and pressed at 5 - 10 MPa. The hydrothermal reactions between calcium hydroxide and rice husk ash over the temperature range 80 - 160 o C were investigated. The period of autoclave treatment was from 2 to 72 h. After the hydrothermal treatment of the samples, the mineralogical composition, bulk density, density, cold crushing strength, porosity, refractoriness and thermal expansion were examined. Analysing the properties of the obtained samples it can be concluded that from rice husk ash and calcium hydroxide under hydrothermal condition it is possible to obtain lightweight acid refractory material with high quality.(Author)

Some genetic aspects of hydrothermal uranium deposits in the Bakulja granitoide (Serbia)

International Nuclear Information System (INIS)

Jelenkovic, Rade

1998-01-01

This paper discusses the influence of temperature and the way of hydrothermal fluids flow in function of both the degree of tectonized granitoid and the origin of solutions, and partly the processes accompanying mineralization expressed through physico-chemical, mineralogical and mechanical alterations of the mother rock. It has been concluded that heat energy exchange is in function of: 1) petrochemical characteristic of a rock the hydrothermal fluids flow through; 2) degree of tectonization of the surrounding mineralized rocks; 3) volume and morphology of the fissured-porous space; 4) form of uranium bonding in mineral carriers; 5) degree of uranium leaching in hydrothermal solutions; 6) the way of hydrothermal fluids flow, and 7) coefficient of heat exchange expressed by distribution of heat energy within a fluid-rock system. It has also been established that contraction of granite volume results from physico-chemical processes that take place within a granitoid-hydrothermal fluid system and its quantification has been carried out. (Author)

Heat flux from magmatic hydrothermal systems related to availability of fluid recharge

Science.gov (United States)

Harvey, M. C.; Rowland, J.V.; Chiodini, G.; Rissmann, C.F.; Bloomberg, S.; Hernandez, P.A.; Mazot, A.; Viveiros, F.; Werner, Cynthia A.

2015-01-01

Magmatic hydrothermal systems are of increasing interest as a renewable energy source. Surface heat flux indicates system resource potential, and can be inferred from soil CO2 flux measurements and fumarole gas chemistry. Here we compile and reanalyze results from previous CO2 flux surveys worldwide to compare heat flux from a variety of magma-hydrothermal areas. We infer that availability of water to recharge magmatic hydrothermal systems is correlated with heat flux. Recharge availability is in turn governed by permeability, structure, lithology, rainfall, topography, and perhaps unsurprisingly, proximity to a large supply of water such as the ocean. The relationship between recharge and heat flux interpreted by this study is consistent with recent numerical modeling that relates hydrothermal system heat output to rainfall catchment area. This result highlights the importance of recharge as a consideration when evaluating hydrothermal systems for electricity generation, and the utility of CO2 flux as a resource evaluation tool.

Sort-Mid tasks scheduling algorithm in grid computing

Directory of Open Access Journals (Sweden)

Naglaa M. Reda

2015-11-01

Full Text Available Scheduling tasks on heterogeneous resources distributed over a grid computing system is an NP-complete problem. The main aim for several researchers is to develop variant scheduling algorithms for achieving optimality, and they have shown a good performance for tasks scheduling regarding resources selection. However, using of the full power of resources is still a challenge. In this paper, a new heuristic algorithm called Sort-Mid is proposed. It aims to maximizing the utilization and minimizing the makespan. The new strategy of Sort-Mid algorithm is to find appropriate resources. The base step is to get the average value via sorting list of completion time of each task. Then, the maximum average is obtained. Finally, the task has the maximum average is allocated to the machine that has the minimum completion time. The allocated task is deleted and then, these steps are repeated until all tasks are allocated. Experimental tests show that the proposed algorithm outperforms almost other algorithms in terms of resources utilization and makespan.

Collaborative Distributed Scheduling Approaches for Wireless Sensor Network

Directory of Open Access Journals (Sweden)

Zhidong Deng

2009-10-01

Full Text Available Energy constraints restrict the lifetime of wireless sensor networks (WSNs with battery-powered nodes, which poses great challenges for their large scale application. In this paper, we propose a family of collaborative distributed scheduling approaches (CDSAs based on the Markov process to reduce the energy consumption of a WSN. The family of CDSAs comprises of two approaches: a one-step collaborative distributed approach and a two-step collaborative distributed approach. The approaches enable nodes to learn the behavior information of its environment collaboratively and integrate sleep scheduling with transmission scheduling to reduce the energy consumption. We analyze the adaptability and practicality features of the CDSAs. The simulation results show that the two proposed approaches can effectively reduce nodes’ energy consumption. Some other characteristics of the CDSAs like buffer occupation and packet delay are also analyzed in this paper. We evaluate CDSAs extensively on a 15-node WSN testbed. The test results show that the CDSAs conserve the energy effectively and are feasible for real WSNs.

Development of an improved installation procedure and schedule of RVI modularization for APR1400

International Nuclear Information System (INIS)

Ko, Do Young

2011-01-01

The construction technology for reactor vessel internals (RVI) modularization is one of the most important factors to be considered in reducing the construction period of nuclear power plants. For RVI modularization, gaps between the reactor vessel (RV) core-stabilizing lug and the core support barrel (CSB) snubber lug must be measured using a remote method from outside the RV. In order to measure RVI gaps remotely at nuclear power plant construction sites, certain core technologies must be developed and verified. These include a remote measurement system to measure the gaps between the RV core-stabilizing lug and the CSB snubber lug, an RVI mockup to perform the gap measurement tests, and a new procedure and schedule for RVI installation. A remote measurement system was developed previously, and a gap measurement test was completed successfully using the RVI mockup. We also developed a new procedure and schedule for RVI installation. This paper presents the new and improved installation procedure and schedule for RVI modularization. These are expected to become core technologies that will allow us to shorten the construction period by a minimum of two months compared to the existing installation procedure and schedule

Optimal household appliances scheduling under day-ahead pricing and load-shaping demand response strategies

NARCIS (Netherlands)

Paterakis, N.G.; Erdinç, O.; Bakirtzis, A.G.; Catalao, J.P.S.

2015-01-01

In this paper, a detailed home energy management system structure is developed to determine the optimal dayahead appliance scheduling of a smart household under hourly pricing and peak power-limiting (hard and soft power limitation)-based demand response strategies. All types of controllable assets

Optimal residential smart appliances scheduling considering distribution network constraints

Directory of Open Access Journals (Sweden)

Yu-Ree Kim

2016-01-01

Full Text Available As smart appliances (SAs are more widely adopted within distribution networks, residential consumers can contribute to electricity market operations with demand response resources and reduce their electricity bill. However, if the schedules of demand response resources are determined only by the economic electricity rate signal, the schedule can be unfeasible due to the distribution network constraints. Furthermore, it is impossible for consumers to understand the complex physical characteristics and reflect them in their everyday behaviors. This paper introduces the concept of load coordinating retailer (LCR that deals with demand responsive appliances to reduce electrical consumption for the given distribution network constraints. The LCR can play the role of both conventional retailer and aggregated demand response provider for residential customers. It determines the optimal schedules for the aggregated neighboring SAs according to their types within each distribution feeder. The optimization algorithms are developed using Mixed Integer Linear Programming, and the distribution network is solved by the Newton–Raphson AC power flow.

Improved human performance through appropriate work scheduling

International Nuclear Information System (INIS)

Morisseau, D.S.; Lewis, P.M.; Persensky, J.J.

1987-01-01

The Nuclear Regulatory Commission (NRC) has had a policy, Generic Letter 82-12, on hours of work since 1982. The policy states that licensees should establish controls to prevent situations where fatigue could reduce the ability of operating personnel to perform their duties safely (USNRC 1982). While that policy does give guidance on hours of work and overtime, it does not address periods of longer than 7 days or work schedules other than the routine 8-hour day, 40-hour week. Recognizing that NRC policy could provide broader guidance for shift schedules and hours of overtime work, the Division of Human Factors Safety conducted a project with Pacific Northwest Laboratories (PNL) to help the NRC better understand the human factors principles and issues concerning hours of work so that the NRC could consider updating their policy as necessary. The results of this project are recommendations for guidelines and limits for periods of 14 days, 28 days, and 1 year to take into account the cumulative effects of fatigue. In addition, routine 12-hour shifts are addressed. This latter type of shift schedule has been widely adopted in the petroleum and chemical industries and several utilities operating nuclear power plants have adopted it as well. Since this is the case, it is important to consider including guidelines for implementing this type of schedule. This paper discusses the bases for the PNL recommendations which are currently being studied by the NRC

Hydrothermal plume anomalies over the southwest Indian ridge: magmatic control

Science.gov (United States)

Yue, X.; Li, H.; Tao, C.; Ren, J.; Zhou, J.; Chen, J.; Chen, S.; Wang, Y.

2017-12-01

Here we firstly reported the extensive survey results of the hydrothermal activity along the ultra-slow spreading southwest Indian ridge (SWIR). The study area is located at segment 27, between the Indomed and Gallieni transform faults, SWIR. The seismic crustal thickness reaches 9.5km in this segment (Li et al., 2015), which is much thicker than normal crustal. The anomaly thickened crust could be affected by the Crozet hotspot or highly focused melt delivery from the mantle. The Duanqiao hydrothermal field was reported at the ridge valley of the segment by Tao et al (2009). The Deep-towed Hydrothermal Detection System (DHDS) was used to collect information related with hydrothermal activity, like temperature, turbidity, oxidation-reduction potential (ORP) and seabed types. There are 15 survey lines at the interval of 2 to 3 km which are occupied about 1300 km2 in segment 27. After processing the raw data, including wiping out random noise points, 5-points moving average processing and subtracting the ambient, we got anomalous Nephelometric Turbidity Units values (ΔNTU). And dE/dt was used to identify the ORP anomalous as the raw data is easily influenced by electrode potentials drifting (Baker et al., 2016). According to the results of water column turbidity and ORP distributions, we confirmed three hydrothermal anomaly fields named A1, A2 and A3. The three fields are all located in the western part of the segment. The A1 field lies on the ridge valley, west side of Duanqiao field. The A2 and A3 field lie on the northern and southern of the ridge valley, respectively. We propose that recent magmatic activity probably focus on the western part of segment 27.And the extensive distribution of hydrothermal plume in the segment is the result of the discrete magma intrusion. References Baker E T, et al. How many vent fields? New estimates of vent field populations on ocean ridges from precise mapping of hydrothermal discharge locations. EPSL, 2016, 449:186-196. Li J

Free-living nematode species (Nematoda) dwelling in hydrothermal sites of the North Mid-Atlantic Ridge

Science.gov (United States)

Tchesunov, Alexei V.

2015-12-01

Morphological descriptions of seven free-living nematode species from hydrothermal sites of the Mid-Atlantic Ridge are presented. Four of them are new for science: Paracanthonchus olgae sp. n. (Chromadorida, Cyatholaimidae), Prochromadora helenae sp. n. (Chromadorida, Chromadoridae), Prochaetosoma ventriverruca sp. n. (Desmodorida, Draconematidae) and Leptolaimus hydrothermalis sp. n. (Plectida, Leptolaimidae). Two species have been previously recorded in hydrothermal habitats, and one species is recorded for the first time in such an environment. Oncholaimus scanicus (Enoplida, Oncholaimidae) was formerly known from only the type locality in non-hydrothermal shallow milieu of the Norway Sea. O. scanicus is a very abundant species in Menez Gwen, Lucky Strike and Lost City hydrothermal sites, and population of the last locality differs from other two in some morphometric characteristics. Desmodora marci (Desmodorida, Desmodoridae) was previously known from other remote deep-sea hydrothermal localities in south-western and north-eastern Pacific. Halomonhystera vandoverae (Monhysterida, Monhysteridae) was described and repeatedly found in mass in Snake Pit hydrothermal site. The whole hydrothermal nematode assemblages are featured by low diversity in comparison with either shelf or deep-sea non-hydrothermal communities. The nematode species list of the Atlantic hydrothermal vents consists of representatives of common shallow-water genera; the new species are also related to some shelf species. On the average, the hydrothermal species differ from those of slope and abyssal plains of comparable depths by larger sizes, diversity of buccal structures, presence of food content in the gut and ripe eggs in uteri.

Research on wind power grid-connected operation and dispatching strategies of Liaoning power grid

Science.gov (United States)

Han, Qiu; Qu, Zhi; Zhou, Zhi; He, Xiaoyang; Li, Tie; Jin, Xiaoming; Li, Jinze; Ling, Zhaowei

2018-02-01

As a kind of clean energy, wind power has gained rapid development in recent years. Liaoning Province has abundant wind resources and the total installed capacity of wind power is in the forefront. With the large-scale wind power grid-connected operation, the contradiction between wind power utilization and peak load regulation of power grid has been more prominent. To this point, starting with the power structure and power grid installation situation of Liaoning power grid, the distribution and the space-time output characteristics of wind farm, the prediction accuracy, the curtailment and the off-grid situation of wind power are analyzed. Based on the deep analysis of the seasonal characteristics of power network load, the composition and distribution of main load are presented. Aiming at the problem between the acceptance of wind power and power grid adjustment, the scheduling strategies are given, including unit maintenance scheduling, spinning reserve, energy storage equipment settings by the analysis of the operation characteristics and the response time of thermal power units and hydroelectric units, which can meet the demand of wind power acceptance and provide a solution to improve the level of power grid dispatching.

Heavy metals from Kueishantao shallow-sea hydrothermal vents, offshore northeast Taiwan

Science.gov (United States)

Chen, Xue-Gang; Lyu, Shuang-Shuang; Garbe-Schönberg, Dieter; Lebrato, Mario; Li, Xiaohu; Zhang, Hai-Yan; Zhang, Ping-Ping; Chen, Chen-Tung Arthur; Ye, Ying

2018-04-01

Shallow water hydrothermal vents are a source of heavy metals leading to their accumulation in marine organisms that manage to live under extreme environmental conditions. This is the case at Kueishantao (KST) shallow-sea vents system offshore northeast Taiwan, where the heavy metal distribution in vent fluids and ambient seawater is poorly understood. This shallow vent is an excellent natural laboratory to understand how heavy and volatile metals behave in the nearby water column and ecosystem. Here, we investigated the submarine venting of heavy metals from KST field and its impact on ambient surface seawater. The total heavy metal concentrations in the vent fluids and vertical plumes were 1-3 orders of magnitude higher than the overlying seawater values. When compared with deep-sea hydrothermal systems, the estimated KST end-member fluids exhibited much lower concentrations of transition metals (e.g., Fe and Mn) but comparable concentrations of toxic metals such as Pb and As. This may be attributed to the lower temperature of the KST reaction zone and transporting fluids. Most of the heavy metals (Fe, Mn, As, Y, and Ba) in the plumes and seawater mainly originated from hydrothermal venting, while Cd and Pb were largely contributed by external sources such as contaminated waters (anthropogenic origin). The spatial distribution of heavy metals in the surface seawater indicated that seafloor venting impacts ambient seawater. The measurable influence of KST hydrothermal activity, however, was quite localized and limited to an area of heavy metals emanating from the yellow KST hydrothermal vent were: 430-2600 kg Fe, 24-145 kg Mn, 5-32 kg Ba, 10-60 kg As, 0.3-1.9 kg Cd, and 2-10 kg Pb. This study provides important data on heavy metals from a shallow-sea hydrothermal field, and it helps to better understand the environmental impact of submarine shallow hydrothermal venting.

Exploration Method Development for hydrothermal plume hunting by XCTD

Science.gov (United States)

Kitagawa, Y.; Ikeda, M.; Kadoshima, K.; Koizumi, Y.; Nakano, J.; Asakawa, E.; Sumi, T.

2017-12-01

J-MARES (Research and Development Partnership for Next Generation Technology of Marine Resources Survey, JAPAN) has been designing a low-cost and high-efficiency exploration system for seafloor hydrothermal massive sulfide deposits in "Cross-ministerial Strategic Innovation Promotion Program (SIP)" granted by the Cabinet Office, Government of Japan since 2014. We proposed hydrothermal plume hunting by XCTD (eXpendables Conductivity, Temperature and Depth). We applied this method to an area of interest more than 100km x 100km over Okinawa Trough, including some known seafloor massive sulfide deposits. Generally, hydrothermal plume exploration has been by ship mounted with MBES (Multi Beam Echo Sounder) or AUV with sound anomaly observation. However, these methods have to charter the sophisticated ship costly. On the other hand, throw-in type water quality meters (eg. XCTD and XBT) can be low-cost and easily operable. Moreover, that can make a quick look at seawater temperature and conductivity even in rough waters.Firstly, we confirmed XCTD probes position on the seafloor by ROV mounted deep-sea high vision camera. As a result of the test, probes swept downstream about 40 m in horizontal distance from throwing positions with about 1,600m in water depth. Following the previous test results, we had performed to the next test that confirmed detection range of hydrothermal plume at the chimney of North Mound in Izena Cauldron, so we had caught anomaly of seawater temperature and conductivity successfully which could be possibly derived from hydrothermal activities. Although averaged seawater temperature at a depth of 1500 m or more was about 3.95 degrees C, near the chimney was about 4.93 degrees C. The temperature anomalies originated from the hydrothermal plumes could be distributed at most 30m in horizontal distance and became smaller away from the chimney. Moreover, temperature anomaly mass of sea water tended to move upward in depth with distance away from the

29 CFR 825.203 - Scheduling of intermittent or reduced schedule leave.

Science.gov (United States)

2010-07-01

... leave intermittently or on a reduced leave schedule for planned medical treatment, then the employee... 29 Labor 3 2010-07-01 2010-07-01 false Scheduling of intermittent or reduced schedule leave. 825... OF LABOR OTHER LAWS THE FAMILY AND MEDICAL LEAVE ACT OF 1993 Employee Leave Entitlements Under the...

ATLAS construction schedule

CERN Multimedia

Kotamaki, M

The goal during the last few months has been to freeze and baseline as much as possible the schedules of various ATLAS systems and activities. The main motivations for the re-baselining of the schedules have been the new LHC schedule aiming at first collisions in early 2006 and the encountered delays in civil engineering as well as in the production of some of the detectors. The process was started by first preparing a new installation schedule that takes into account all the new external constraints and the new ATLAS staging scenario. The installation schedule version 3 was approved in the March EB and it provides the Ready For Installation (RFI) milestones for each system, i.e. the date when the system should be available for the start of the installation. TCn is now interacting with the systems aiming at a more realistic and resource loaded version 4 before the end of the year. Using the new RFI milestones as driving dates a new summary schedule has been prepared, or is under preparation, for each system....

Enhanced bioactivity and biocompatibility of nanostructured hydroxyapatite coating by hydrothermal annealing

International Nuclear Information System (INIS)

Hahn, Byung-Dong; Lee, Jeong-Min; Park, Dong-Soo; Choi, Jong-Jin; Ryu, Jungho; Yoon, Woon-Ha; Choi, Joon-Hwan; Lee, Byoung-Kuk; Kim, Jong-Woo; Kim, Hyoun-Ee; Kim, Seong-Gon

2011-01-01

The crystallinity of hydroxyapatite (HA) coatings prepared by aerosol deposition may be increased by heating in air or low-temperature hydrothermal processing. From the X-ray diffraction and Fourier transform infrared spectroscopy results, it was revealed that the crystallinity of the HA coatings significantly increased after the post-annealing. Transmission electron microscopy showed that the conventional furnace heating induced the substantial growth of the HA crystallites, whereas the hydrothermal treatment did not bring about any remarkable change in the HA crystallite size, which remained below 20 nm. The bioactivity of the HA coatings was estimated by the acellular simulated body fluid immersion test. After immersion for 7 days, newly-precipitated apatite crystals were only observed on the surfaces of the samples hydrothermally treated at 170 and 190 deg. C. In addition, the alkaline phosphatase activity of MC3T3-E1 preosteoblast cells cultured on the hydrothermally treated samples was significantly higher than those on the as-deposited coating and conventional furnace heated samples. The enhanced bioactivity and excellent biological in vitro cellular response of the hydrothermally treated samples were attributed to their nanostructured nature and high degree of crystallinity.

Sulfur metabolizing microbes dominate microbial communities in Andesite-hosted shallow-sea hydrothermal systems.

Directory of Open Access Journals (Sweden)

Yao Zhang

Full Text Available To determine microbial community composition, community spatial structure and possible key microbial processes in the shallow-sea hydrothermal vent systems off NE Taiwan's coast, we examined the bacterial and archaeal communities of four samples collected from the water column extending over a redoxocline gradient of a yellow and four from a white hydrothermal vent. Ribosomal tag pyrosequencing based on DNA and RNA showed statistically significant differences between the bacterial and archaeal communities of the different hydrothermal plumes. The bacterial and archaeal communities from the white hydrothermal plume were dominated by sulfur-reducing Nautilia and Thermococcus, whereas the yellow hydrothermal plume and the surface water were dominated by sulfide-oxidizing Thiomicrospira and Euryarchaeota Marine Group II, respectively. Canonical correspondence analyses indicate that methane (CH(4 concentration was the only statistically significant variable that explains all community cluster patterns. However, the results of pyrosequencing showed an essential absence of methanogens and methanotrophs at the two vent fields, suggesting that CH(4 was less tied to microbial processes in this shallow-sea hydrothermal system. We speculated that mixing between hydrothermal fluids and the sea or meteoric water leads to distinctly different CH(4 concentrations and redox niches between the yellow and white vents, consequently influencing the distribution patterns of the free-living Bacteria and Archaea. We concluded that sulfur-reducing and sulfide-oxidizing chemolithoautotrophs accounted for most of the primary biomass synthesis and that microbial sulfur metabolism fueled microbial energy flow and element cycling in the shallow hydrothermal systems off the coast of NE Taiwan.

Sulfur metabolizing microbes dominate microbial communities in Andesite-hosted shallow-sea hydrothermal systems.

Science.gov (United States)

Zhang, Yao; Zhao, Zihao; Chen, Chen-Tung Arthur; Tang, Kai; Su, Jianqiang; Jiao, Nianzhi

2012-01-01

To determine microbial community composition, community spatial structure and possible key microbial processes in the shallow-sea hydrothermal vent systems off NE Taiwan's coast, we examined the bacterial and archaeal communities of four samples collected from the water column extending over a redoxocline gradient of a yellow and four from a white hydrothermal vent. Ribosomal tag pyrosequencing based on DNA and RNA showed statistically significant differences between the bacterial and archaeal communities of the different hydrothermal plumes. The bacterial and archaeal communities from the white hydrothermal plume were dominated by sulfur-reducing Nautilia and Thermococcus, whereas the yellow hydrothermal plume and the surface water were dominated by sulfide-oxidizing Thiomicrospira and Euryarchaeota Marine Group II, respectively. Canonical correspondence analyses indicate that methane (CH(4)) concentration was the only statistically significant variable that explains all community cluster patterns. However, the results of pyrosequencing showed an essential absence of methanogens and methanotrophs at the two vent fields, suggesting that CH(4) was less tied to microbial processes in this shallow-sea hydrothermal system. We speculated that mixing between hydrothermal fluids and the sea or meteoric water leads to distinctly different CH(4) concentrations and redox niches between the yellow and white vents, consequently influencing the distribution patterns of the free-living Bacteria and Archaea. We concluded that sulfur-reducing and sulfide-oxidizing chemolithoautotrophs accounted for most of the primary biomass synthesis and that microbial sulfur metabolism fueled microbial energy flow and element cycling in the shallow hydrothermal systems off the coast of NE Taiwan.

Comparative assessment of five potential sites for hydrothermal magma systems: geochemistry

Energy Technology Data Exchange (ETDEWEB)

White, A.F.

1980-08-01

A brief discussion is given of the geochemical objectives and questions that must be addressed in such an evaluation. A summary of the currently published literature that is pertinent in answering these questions is presented for each of the five areas: The Geysers-Clear Lake region, Long Valley, Rio Grand Rift, Roosevelt Hot Springs, and the Salton Trough. The major geochemical processes associated with proposed hydrothermal sites are categorized into three groups for presentation: geochemistry of magma and associated volcanic rocks, geochemistry of hydrothermal solutions, and geochemistry of hydrothermal alteration. (MHR)

Selective oxidation of propylene to acrolein by hydrothermally synthesized bismuth molybdates

DEFF Research Database (Denmark)

Schuh, Kirsten; Kleist, Wolfgang; Høj, Martin

2014-01-01

Hydrothermal synthesis has been used as a soft chemical method to prepare bismuth molybdate catalysts for the selective oxidation of propylene to acrolein. All obtained samples displayed a plate-like morphology, but their individual aspect ratios varied with the hydrothermal synthesis conditions...... of nitric acid during hydrothermal synthesis enhanced both propylene conversion and acrolein yield, possibly due to a change in morphology. Formation of β-Bi2Mo2O9 was not observed under the applied conditions. In general, the catalytic performance of all samples decreased notably after calcination at 550...

Hydrothermal Disintegration and Extraction of Different Microalgae Species

Directory of Open Access Journals (Sweden)

Michael Kröger

2018-02-01

Full Text Available For the disintegration and extraction of microalgae to produce lipids and biofuels, a novel processing technology was investigated. The utilization of a hydrothermal treatment was tested on four different microalgae species (Scenedesmus rubescens, Chlorella vulgaris, Nannochloropsis oculata and Arthorspira platensis (Spirulina to determine whether it has an advantage in comparison to other disintegration methods for lipid extraction. It was shown, that hydrothermal treatment is a reasonable opportunity to utilize microalgae without drying and increase the lipid yield of an algae extraction process. For three of the four microalgae species, the extraction yield with a prior hydrothermal treatment elevated the lipid yield up to six times in comparison to direct extraction. Only Scenedesmus rubescens showed a different behaviour. Reason can be found in the different cell wall of the species. The investigation of the differences in cell wall composition of the used species indicate that the existence of algaenan as a cell wall compound plays a major role in stability.

Characteristics of Biochar Obtained by Hydrothermal Carbonization of Cellulose for Renewable Energy

OpenAIRE

Daegi Kim; Kunio Yoshikawa; Ki Young Park

2015-01-01

The effect of hydrothermal carbonization on the properties of cellulose present in lignocellulosic biomass was investigated for converting it into a renewable energy resource with high energy recovery efficiency. The biochar obtained from cellulose subjected to hydrothermal carbonization showed a significant increase in its carbon content and a calorific value. 13C NMR spectroscopy showed that when raw cellulose was subjected to hydrothermal carbonization above 220 °C, the resulting biochar h...

Distributed Estimation, Coding, and Scheduling in Wireless Visual Sensor Networks

Science.gov (United States)

Yu, Chao

2013-01-01

In this thesis, we consider estimation, coding, and sensor scheduling for energy efficient operation of wireless visual sensor networks (VSN), which consist of battery-powered wireless sensors with sensing (imaging), computation, and communication capabilities. The competing requirements for applications of these wireless sensor networks (WSN)…

Hydrothermal germination models: Improving experimental efficiency by limiting data collection to the relevant hydrothermal range

Science.gov (United States)

Hydrothermal models used to predict germination response in the field are usually parameterized with data from laboratory experiments that examine the full range of germination response to temperature and water potential. Inclusion of low water potential and high and low-temperature treatments, how...

Providing frequency regulation reserve services using demand response scheduling

International Nuclear Information System (INIS)

Motalleb, Mahdi; Thornton, Matsu; Reihani, Ehsan; Ghorbani, Reza

2016-01-01

Highlights: • Proposing a market model for contingency reserve services using demand response. • Considering transient limitations of grid frequency for inverter-based generations. • Price-sensitive scheduling of residential batteries and water heaters using dynamic programming. • Calculating the profits of both generation companies and demand response aggregators. - Abstract: During power grid contingencies, frequency regulation is a primary concern. Historically, frequency regulation during contingency events has been the sole responsibility of the power utility. We present a practical method of using distributed demand response scheduling to provide frequency regulation during contingency events. This paper discusses the implementation of a control system model for the use of distributed energy storage systems such as battery banks and electric water heaters as a source of ancillary services. We present an algorithm which handles the optimization of demand response scheduling for normal operation and during contingency events. We use dynamic programming as an optimization tool. A price signal is developed using optimal power flow calculations to determine the locational marginal price of electricity, while sensor data for water usage is also collected. Using these inputs to dynamic programming, the optimal control signals are given as output. We assume a market model in which distributed demand response resources are sold as a commodity on the open market and profits from demand response aggregators as brokers of distributed demand response resources can be calculated. In considering control decisions for regulation of transient changes in frequency, we focus on IEEE standard 1547 in order to prevent the safety shut-off of inverter-based generation and further exacerbation of frequency droop. This method is applied to IEEE case 118 as a demonstration of the method in practice.

Clean Coal Power at Toms Creek

International Nuclear Information System (INIS)

Schmid, M.R.