594 research outputs found

    Ultracapacitors for port crane applications: Sizing and techno-economic analysis

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    The use of energy storage with high power density and fast response time at container terminals (CTs) with a power demand of tens of megawatts is one of the most critical factors for peak reduction and economic benefits. Peak shaving can balance the load demand and facilitate the participation of small power units in generation based on renewable energies. Therefore, in this paper, the economic efficiency of peak demand reduction in ship to shore (STS) cranes based on the ultracapacitor (UC) energy storage sizing has been investigated. The results show the UC energy storage significantly reduce the peak demand, increasing the load factor, load leveling, and most importantly, an outstanding reduction in power and energy cost. In fact, the suggested approach is the start point to improve reliability and reduce peak demand energy consumption

    Single cell box girder bridges of deformable cross-section.

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    SIGLEAvailable from British Library Document Supply Centre- DSC:DX82780 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    Differentially Private All-Pairs Shortest Distances for Low Tree-Width Graphs

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    In this paper, we present a polynomial time algorithm for the problem of differentially private all pair shortest distances over the class of low tree-width graphs. Our result generalizes the result of Sealfon 2016 for the case of trees to a much larger family of graphs. Furthermore, if we restrict to the class of low tree-width graphs, the additive error of our algorithm is significantly smaller than that of the best known algorithm for this problem, proposed by Chen et. al. 2023

    The relation characteristics of personality of managers working in Iran University of Medical Sciences with success and desirable job

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    Background: Several studies suggest the existence of an effective relationship between individuals' characteristics and important factors such as occupational and organizational performance, job satisfaction, organizational commitment, and etc. This study was designed based on the dimensions of personality (introversion/extroversion) of managers of Iran University of Medical Sciences at three levels (executive, middle and senior) with their career success rate. Methods: This was a cross-sectional descriptive study, whose population was all managers of Iran University of Medical Sciences. To collect data, two valid and reliable questionnaires were used. The first questionnaire assessed personality characteristics of each director, and the second measured occupational success. Related tests such as Pearson correlation test and independent comparison (independent t-test) at a significance level of 0.05 were used for data analysis. Results: Findings revealed no significant relationship between variables of introversion and extroversion and occupational success among the senior managers, (p > 0.05). However, there was a direct but incomplete relationship between introversion and extroversion, which correlated with job success among middle and executives managers. Conclusion: It seems that in all three levels of managers, if the managers communicated more with employees and if the subject of communication was more of executive nature, the correlation rate would increase between extroversion and introversion with job success variables. Therefore, it is suggested to give attention to organizational interaction and communication, and contingency variables such as organization condition, structure, formality and complexity

    A finite-difference formulation of elastic rod for the design of actively bent structures

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    A discrete formulation of elastic rod has been tailored for the particular design task of geometric modelling, form finding and analysis of actively bent structural systems. The rod element is fully described by using vector based quantities, hence making it easy to implement and be suitable for explicit resolution methods such as the Dynamic Relaxation (DR). From this point of view, the model under consideration aims to provide a natural enhancement, of existing DR schemes of elastic rods, primarily formulated for analysis/design of stressed spline structures with isotropic cross-section, whilst, the proposed formulation allows for the general case of initially straight rods with anisotropic cross-section and torsionalstiffness effects, to be taken into consideration. In order to avoid numerical conditioning problems, the method adopts a reduced Degrees of Freedom approach, however, the design limitations usually involved with such an approach, are ‘removed’ by adopting the Bishop theory of framed curves, hence making it possible to reduce to only three (translations) the Degrees of Freedom to be explicitly computed by numerical integration of the corresponding acceleration terms

    Form finding and structural analysis of actively bent timber grid shells

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    Grid shells are efficient structural systems covering large open spaces with relatively small amount of materials. Also, post forming techniques allow realization of geometrically complex (free-form) shapes by means of standard connection systems. However, due to complexity of the analysis–design process, they are rarely utilized in construction design. In this paper, a ‘facilitating’ numerical framework is introduced in which, for a given continuous reference shape, a geometrically similar discrete model is found by implementation of a six degree of freedom formulation of the Dynamic Relaxation method, to handle members bending and torsional stiffness. A grid cutting pattern algorithm is introduced, as well as methods to numerically simulate the double-layer construction technique and a novel (single-node) cylindrical joint model. The methods are extensively tested and validated on a range of structures, from ‘simple’ single-rod cases to more complex, actively bent, grid shell frameworks

    Intelligent energy management based on SCADA system in a real Microgrid for smart building applications

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    Energy management is one of the main challenges in Microgrids (MGs) applied to Smart Buildings (SBs). Hence, more studies are indispensable to consider both modeling and operating aspects to utilize the upcoming results of the system for the different applications. This paper presents a novel energy management architecture model based on complete Supervisory Control and Data Acquisition (SCADA) system duties in an educational building with an MG Laboratory (Lab) testbed, which is named LAMBDA at the Electrical and Energy Engineering Department of the Sapienza University of Rome. The LAMBDA MG Lab simulates in a small scale a SB and is connected with the DIAEE electrical network. LAMBDA MG is composed of a Photovoltaic generator (PV), a Battery Energy Storage System (BESS), a smart switchboard (SW), and different classified loads (critical, essential, and normal) some of which are manageable and controllable (lighting, air conditioning, smart plugs operating into the LAB). The aim of the LAMBDA implementation is making the DIAEE smart for energy saving purposes. In the LAMBDA Lab, the communication architecture consists in a complex of master/slave units and actuators carried out by two main international standards, Modbus (industrial serial standard for electrical and technical monitoring systems) and Konnex (an open standard for commercial and domestic building automation). Making the electrical department smart causes to reduce the required power from the main grid. Hence, to achieve the aims, results have been investigated in two modes. Initially, the real-time mode based on the SCADA system, which reveals real daily power consumption and production of different sources and loads. Next, the simulation part is assigned to shows the behavior of the main grid, loads and BESS charging and discharging based on energy management system. Finally, the proposed model has been examined in different scenarios and evaluated from the economic aspect

    Clinical Features and Differential Diagnoses in Laryngeal Mucoepidermoid Carcinoma

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    Mucoepidermoid carcinoma is the most common malignant tumor of salivary glands. However, it is a rare entity in larynx. Laryngeal cases are frequently misdiagnosed with other malignancies and they are under-reported. So, recognizing the clinical and histological features of this tumor is essential. Laryngeal mucoepidermoid carcinoma can arise in supraglottis, glottis and subglottis. Generally, it presents as a submucosal mass; therefore, progressive symptoms without any identifiable lesion in laryngoscopy must be well considered. The prognosis is somehow dependent on the histological features. In high-grade tumors, recurrence is more common and radical surgery with radiotherapy is recommended. In this paper, we provide a thorough literature review on mucoepidermoid carcinoma in the larynx. The most important distinguishing features of mucoepidermoid carcinoma and its two major differential diagnoses (squamous cell carcinoma and adenosquamous carcinoma) are clearly stated and pitfalls in true diagnosis of this tumor are discussed

    La métaplasie malpighienne dans le carcinome papillaire de la thyroïde

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    Introduction : la métaplasie malpighienne est rare au niveau de la thyroïde. Elle peut être associée à un processus pathologique tumoral ou inflammatoire.Matériels et méthodes : les auteurs se proposent de rapporter une observation de métaplasie malpighienne de la thyroïde associée à un carcinome papillaire diagnostiqué au service d’Anatomie et de Cytologie pathologiques du CHU Farhat Hached de Sousse et d’en discuter la pathogénie de cette métaplasie, ses circonstances de survenue et ses difficultés diagnostiques.Résultats : il s’agissait d’une fille âgée de 9 ans ayant consulté pour un nodule de la thyroïde. Une cytoponction de ce nodule était pratiquée et avait montré la présence de cellules tumorales d’un carcinome papillaire. Une thyroïdectomie totale avec curage triangulaire fonctionnel a été réalisée. L’examen anatomo-pathologique de la pièce a confirmé la présence d’un carcinome papillaire de la thyroïde avec présence au voisinage de la tumeur de plages de cellules malpighiennes d’allure non tumorale.Conclusion : bien que rare, la métaplasie malpighienne peut se voir dans la thyroïde. Elle doit être distinguée d’un carcinome épidermoïde de la thyroïde par la recherche systématique, devant tout foyer de métaplasie malpighienne, des signes de malignité.Mots clés : métaplasie malpighienne, carcinome papillaire, glande thyroïde

    Biosorption and recovery of copper and zinc from aqueous solutions by nonliving biomass of marine brown algae of Sargassum sp.

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    In this study, the biosorption properties of a pre-treated nonliving biomass of marine brown algae of Sargassum species in the removal of Cu 2+ and Zn2+ ions were investigated. Kinetics, equilibrium isotherms, recovery of metals and regeneration of the Sargassum biomass were carried out under different laboratory conditions using batch reactor. Biosorption of Cu2+ and Zn2+ was rapidly occurred onto Sargassum biomass and most of the sorbed metal was bound in less than 60 min. The removal performance for Zn2+ by the biomass was found more than Cu2+, with maximum uptake values of 1.914 and 1.314 mg g-1 dry weight biomass for Zn2+ and Cu2+, respectively. Optimum biosorption pH value of Cu2+ and Zn2+ was determined as 5 at lab temperature. At the optimal condition, metal ion uptake increased with initial Cu2+ and Zn2+ concentration upto 200 and 500 mg L-1, respectively. The Cu2+ and Zn 2+ uptake by Sargassum biomass was best described by pseudo-second order rate equation. The results showed that the Freundlich isotherm model was suitable for describing the passive biosorption of Cu2+ and Zn 2+ by the dead biomass of Sargassum. Removal of the biosorbed Cu 2+ and Zn2+ from Sargassum biomass was successfully achieved by eluting with 0.1 M HNO3 for 15 min and a high degree of metal recovery was observed. For optimum operation in the subsequent metal uptake cycle, regeneration of the Sargassum biomass was efficiently performed by 0.1 M CaCl2 for 15 min. In repeated use of biomass experiment, the Cu2+ and Zn2+ uptake capacity of Sargassum biomass was approximately retained and no significant biomass change took place after three biosorption-desorption cycles. © 2006 Asian Network for Scientific Information
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