Search results for "Operation"

Technical and economical assessment of distributed electrochemical storages for load shifting applications: An Italian case study

2016

Time-of-use (TOU) energy cost management involves the use of energy storage systems (ESSs) by customers to reduce their electricity bills. The ESS is charged during off-peak time periods, when electricity energy prices are low, and discharged during times when on-peak energy prices are applied. This article addresses the question whether it is economically viable to install medium-scale distributed ESSs designed to lower the electricity cost for a customer-side application, assuming flexible electricity tariffs. The technical/economical evaluation is carried out referring to lithium-ion (Li-ion), sodium sulfur (NaS) and vanadium redox battery (VRB) technologies, performing a parametric anal…

Optimal Management of Human Resources in Transhipment Container Ports

2014

Human resources allocation plays a key role in Transhipment Maritime Container Terminals to achieve high levels of productivity and provide high quality services to shipping companies. The deep interest of container terminals in this issue can be supported by optimization methods. In this work, an optimization model is proposed to determine the optimal daily allocation of crane operators and trailer drivers. Different requirements are taken into account for permanent staff, external workers and personnel shortfall. Since workforce undermanning is a crucial factor for both shipping companies and container terminals, we aim to show that personnel shortfalls and operation delays can be signifi…

Polymer/Perovskite Amplifying Waveguides for Active Hybrid Silicon Photonics

2015

The emission properties of hybrid halide perovskites are exploited to implement a stable and very low power operation waveguide optical amplifier integrated in a silicon platform. By optimizing its design with a poly(methyl methacrylate) (PMMA) encapsulation, this novel photonic device presents a net gain of around 10 dB cm−1 and 3–4 nm linewidth with an energy threshold as low as 2 nJ pulse−1 and exhibiting no degradation after one year. This work was supported by Generalitat Valenciana (Project No. ISIC/2012/008), the Universitat Jaume I (Project No. 12I361.01/1), Spanish MINECO (Projects Nos. MAT2013-47192-C3-1-R and TEC2014-53727-C2-1-R) and EU-NAVOLCHI (Project No. 288869).

TeO2-ZnO-La2O3 tellurite glass system investigation for mid-infrared robust optical fibers manufacturing

2021

Abstract TeO2-ZnO-La2O3 (TZL) ternary glasses were investigated in order to manufacture step-index optical fibers with low optical losses in the near- and mid-infrared ranges and superior mechanical properties. To identify appropriate TZL glass compositions for optical fibers manufacturing, the whole vitreous domain of the ternary diagram was explored by characterizing bulk samples from thermal and optical point of view. Investigations were focused on understanding how the refractive index evolves as a function of the composition. For this, several parameters were analyzed such as density, molar volume, oxygen packing density, molar refractivity, polarizability and optical basicity. Finally…

Shakedown optimum design of reinforced concrete framed structures

1994

Structures subjected to variable repeated loads can undergo the shakedown or adaptation phenomenon,-which prevents them from collapse but may cause lack of serviceability, for the plastic deformations developed, although finite, as shakedown occurrence postulates, may exceed some maximum values imposed by external ductility criteria. This paper is devoted to the optimal design of reinforced concrete structures, subjected to variable and repeated loads. For such structures the knowledge of the actual values taken by the plastic deformations, at shakedown occurrence, is a crucial issue. An approximate assessment of such plastic deformations is needed, which is herein provided in the shape of …

OPTIMUM DESIGN OF REINFORCED CONCRETE STRUCTURES UNDER VARIABLE LOADINGS

1987

Abstract This paper presents a method for optimal design of reinforced concrete (RC) structures, subjected to quasi-static variable loads and accounting for cross-sections limited ductility requirements. It consists of a very simple refinement procedure to be applied in the classical Optimal Shakedown Design, (OSD), which leads to a strengthened structure satisfying the requisite that the actual plastic relative rotations, developed at a specified set of critical sections as a result of a variable repeated loading program, do not exceed given upper limits. This strengthened design is a safe but not strictly optimal design and is obtained using the simple rule that the steel reinforcement ar…

Scope Oriented Thermoeconomic analysis of energy systems. Part II: Formation Structure of Optimality for robust design

2010

This paper represents the Part II of a paper in two parts. In Part I the fundamentals of Scope Oriented Thermoeconomics have been introduced, showing a scarce potential for the cost accounting of existing plants; in this Part II the same concepts are applied to the optimization of a small set of design variables for a vapour compression chiller. The method overcomes the limit of most conventional optimization techniques, which are usually based on hermetic algorithms not enabling the energy analyst to recognize all the margins for improvement. The Scope Oriented Thermoeconomic optimization allows us to disassemble the optimization process, thus recognizing the Formation Structure of Optimal…

Optimal design of CHCP plants in the civil sector by Thermoeconomics

2007

The optimization of design and operation of trigeneration plants for civil applications is a very complex task, because of the large number of internal and external variables affecting the energetic and economic results that may be achieved. Further, energy-saving and profit-oriented optimization processes usually lead to different solutions, in terms of plant lay-out, optimal size of components and operation strategy. Thermoeconomic methodologies are very effective theoretical structures for the optimization of industrial energy-systems characterised by regular energy-demand profiles; however, they are hard to use when approaching civil applications and energy systems in unsteady operating…

OPTIMAL POWER FLOW IN ISLANDED MICROGRIDS

In this thesis, studies about OPF in islanded MGs have been carried out. First, an original formulation and solution approach for the OPF problem in islanded distribution systems is proposed. The methodology is well suited for AC microgrids and can be envisioned as a new hierarchical control structure comprising only two levels: primary and tertiary regulation, the latter also providing iso-frequency operating points for all units and optimized droop parameters for primary regulation. The OPF provides a minimum losses operating point for which voltage drops are limited and power sharing is carried out according to the most adequate physical properties of the infrastructure thus giving rise …

Energy-Efficient Resource Allocation and User Scheduling for Collaborative Mobile Clouds With Hybrid Receivers

2016

In this paper, we study the resource allocation and user scheduling algorithm for minimizing the energy cost of data transmission in the context of OFDMA collaborative mobile cloud (CMC) with simultaneous wireless information and power transfer (SWIPT) receivers. The CMC, which consists of several collaborating MTs offers one potential solution for downlink con- tent distribution and for the energy consumption reduction at the terminal side. Meanwhile, as RF signal can carry both informa- tion and energy simultaneously, the induced SWIPT has gained much attention for energy efficiency design of mobile nodes. Previous work on the design of CMC system mainly focused on the cloud formulation o…