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Abstract

Corrosion inhibition of steel by Polyurethane Extract-primer (PEP) containing plant leaf extracts was compared with Polyurethane Conventional primer (PCP) containing zinc phosphate and zinc chromate as inhibitors. The primers were investigated using gasometric technique in 5 °C steps of temperature increase from 25 to 50 °C in 1.0 M HCl as corrodent. The PEP of 34.24 percent actives compared with PCP of 56.35 percent actives gave the same inhibition efficiencies of 82.4%. Extract primers of low percent active concentration were more effective and less expensive than that of conventional primers.

Open access

Abstract

During service, notched designed components such as steam generators in the nuclear power plant usually experience fatigue damage at elevated temperatures, due to the repeated cyclic loadings during start-up and shut-down operations. Under such extreme conditions, the durability of these components is highly-affected. Besides, to assess the fatigue life of these components, a reliable determination of the local stress-strain at the notch-tips is needed. In this work, the maximum strains of circumferentially notched cylindrical specimens were calculated using the most commonly known analytical methods, namely Neuber's rule, modified Neuber's rule, Glinka's rule, and linear rule, with notch root radius of 1.25, 2.5, and 5 mm, made of modified 9Cr–1Mo steel at 550 °C, and subjected to nominal stress amplitudes of ±124.95, ±149.95, and ±174.95 MPa. The calculated local strains were compared to those obtained from Finite Element Analysis (FEA). It was found that all the analytical approximations provided unreliable local strains at the notch-tips, resulting in an overestimation or underestimation of the fatigue life. Therefore, a mathematical model that predicts the fatigue lives for 9Cr–1Mo steel at elevated temperature was proposed in terms of the applied stress amplitude and the fatigue stress concentration factor. The calculated fatigue lifetimes using the proposed model are found to be in good agreement with those obtained experimentally from the literature with relative errors, when the applied stress amplitude is ±149.95 MPa, are of 1.97%,–8.67%, and 13.54%, for notch root radii of 1.25, 2.5, and 5 mm, respectively.

Open access

Abstract

This paper presents a realization of fractional-order Band pass-filter (FOBF) based on the concepts of fractional order inductors and fractional order capacitors. The FOBF is designed and implemented using both simulation and hardware approaches. The proposed filter order is considered up to second order or less with any real positive number. One of the cases is considered when α ≤ 1 and β ≥ 1. In the second case, the filter is designed when β ≤ 1 and α ≥ 1. In order to calculate the optimal filter parameters, the modified Particle Swarm Optimization (mPSO) algorithm has been utilized for coefficient tuning. Also, a generalized approach to design any second order FOBF is discussed in this work. The realization and performance assessment have been carried out in simulation environment as well as in lab experiment with field programmable analog array (FPAA) development board. The experimental results indicate the value of efforts to realize the fractional filter.

Open access

Abstract

For the last few decades, the power sector has been restructuring throughout the world, and because of this, congestion is bound to take place in the network. Congestion can lead to market failure, violate transmission capability limits and high electricity prices, and end up threatening the power systems’ reliability and security. Increased congestion may also lead to unexpected price differences in power markets leading to market power. In a deregulated power market (DPM), the independent system operator (ISO)’s fundamental challenge is to preserve the power market’s reliability and safety by improving market efficiency when the network is congested. Therefore, congestion management (CM) is essential in DPM and is the key to the power system. This paper carries out a congestion management methods survey to bring together all recent publications in the DPM. It aims to help readers summarize progressive CM methods, along with traditional CM methods that have been discussed so far. In this paper, we have carried out a comparative survey of the various well-known CM methods.

Open access

Abstract

Flow-like landslides are a serious geologic hazard that can cause life and property loss all over the world. Mudflow is a kind of debris flow that has been classified as a non-Newtonian flow. The Smoothed particle hydrodynamics method (SPH) is a powerful tool for modeling fluids, such as debris/mudflows, which can be described in terms of local interactions of their constituent parts. In this paper, the Herschel-Buckley rheology model and SPH are used to simulate free-surface mudflow under the gate. The run-out distance and velocity of mudflow during the time are calculated with numerical simulation and compared with the laboratory result. Our results indicate the rate of increase of run-out and viscosity in the computer model is more than the experimental model and it is because of friction that is assumed to be zero. In the computer simulation, friction is exactly zero but in the experimental model, it could be measured and assumed zero. Finally, Abacus had a good result and can be used for mudflow simulation and protection of run-out distance and viscosity.

Open access

Abstract

In this study, the relationship between the structure of the supporting frame and cells is addressed.

The possible arrangements of the four primary structural elements – foundation, walls and pillars, slabs, roof – in global form as well as in a single cell are looked at. The types of connections of each support member to the support elements below are examined. In line with this, the layout and possible structure of the foundation, and the possible layout of walls and pillars as well as slab is reviewed. The main possibilities for structural design of the roof structure are outlined.

Using the concepts of cells, and arrangement and division of cells there is given some applications. The different building types that can be interpreted using arrangement of cells as well as some applications are shown.

Open access

Freund Vilmos munkássága a Fővárosi Középítési Bizottmányban

A 175 éve született építész életművének egy máig nem kutatott fejezete

The Work by Vilmos Freund in the Metropolitan Commission of Public Architecture

An Unresearched Chapter of the Work of an Architect Born 175 Years Ago
Építés - Építészettudomány
Author: Jeney András

Freund Vilmos (1846 1920), Gottfried Semper tanítványa a dualizmus korabeli Budapest egyik igen termékeny építőművésze volt. Több mint félszáz épületet alkotott a fővárosban. Főleg olasz neoreneszánsz stílusban tervezte meg épületeit. 1900 után már szinte egyáltalán nem alkotott építészként. Építészi tapasztalata megszerzését követően, 1891 körül egyre aktívabb szakmapolitikai tevékenységbe kezdett. Tanulmányunk ismerteti a Fővárosi Középítési Bizottmány szerepét, majd Freund itt végzett munkáját mutatja be, beszédeinek nagyrészt az egykorú Fővárosi Közlönyben megjelent szó szerinti rögzítése alapján. Először a gyakor lati, technológiai ügyek terén tett felszólalásait ismertetjük. Itt többek között kiviláglik Freund útburkolatokkal kapcsolatos komoly tudása, és az, hogy figyelemmel kísérte azon útvonalak állapotát, ahol általa tervezett paloták álltak. Ezt követik a más építészek plánumaival és épületeivel kapcsolatos megszólalásai. A vele egykorú vagy nála fiatalabb alkotók műveivel kapcsolatos javaslatait, illetve véleményét ismerhetjük meg. Végül pedig a „legizgalmasabb” témát, a városrendezés terén elhangzott hozzászólásait tárgyaljuk. Meglepő, hogy néhány, városképileg igen meghatározó épület létrejöttében vagy megépült formájuknak kialakításában is szerepe volt. Például az új tőzsdepalota kezdeményezését és Szabadság térre helyezését két másik építész (Hauszmann Alajos és Quittner Zsigmond) mellett ő kezdeményezte. A piaristák Duna-korzón álló épületének megjelenésére is hatással volt. Freund az igen jelentős építészeti életművén kívül a szakmapolitikai tevékenységével is figyelemre méltót alkotott Budapesten.

Vilmos Freund (1846–1920) was a prominent Hungarian architect who lived during the period of the Austro-Hungarian Empire. He was a student of Gottfried Semper. The majority of the buildings by Freund were built in Budapest. His most preferred style was the Italian Neo-Renaissance. From about 1891 he had an architectural political carrier too. After 1900 he radically reduced the number of his designing work. This study is written about his work in the Metropolitan Commission of Public Architecture (Fővárosi Középítési Bizottmány). His speeches in this commission survived until today as word-by-word recordings published in the old bulletins. The first chapter deals with his speeches in relation to practical, technological affairs for example the paving of the roads of Budapest. He reported his opinion of the designs by other architects, this is the topic of the second chapter. Finally, we can read about his speeches about the great city planning actions. It is interesting that several buildings of Budapest were constructed because he and a few of his colleges initiated them.

Open access

Abstract

Quantum dots (QDs) or semiconductor nanocrystals are luminous materials with unique optical properties that can be fine-tuned by varying the size of the material. Chalcogenide QDs show strong quantum confinements effects owing to the fact that the exciton Bohr radius is much larger than the particle size, and tunable energy bandgap leads to widespread technological interest in near-infrared optical devices. In this communication, one dimensional Cu2SnS3 and PbSexS1-x QDs is modeled by a particle in a box model which was used to compute energies and density of states. The density of states and the energy level of QDs are determined as a function of the strengths of the potential walls of the inner box. The results exhibit that the density of states decreases exponentially with an increase in the energy level of QDs. The density of states at lower energy levels is more significant than what is observed in higher energy levels.

Open access

Abstract

Natural and man-made disasters are vital issues that led to the increasing number of migrants, many of them stayed displaced for decades this requires more permanent dwellings. The main aim of the study is to investigate the impact of the bottom-up construction method on developing migrant’s shelters energy and thermal comfort performance. Dynamic simulation tool Indoor Climate and Energy (IDA ICE 4.8) has been used to assess nine different scenarios. The results quantified that the annually delivered energy and thermal comfort accepted hours of proposed scenario nine (S9) is better compared to base-case scenario one (S1) by 63% kWh and 4,215 h respectively. Methodologies and results of this paper can be adopted and applied for various places of the world affected by migration issue.

Open access

Abstract

Impacts of autonomous truck’s passes on pavement have been analyzed in this research. Two types of lateral positioning namely zero wander and uniform wander along with a super single wide tire and a dual tire have been analyzed with variable traffic speeds in ABQUS. The study concludes with the results in favor of usage of a super single wide tire under a uniform wander mode. The highest amount of pavement damage in terms of maximum rut depth is caused by the dual wheel assembly moving under a zero-wander mode. The magnitude of rut depth increases by a factor of two when a dual tire assembly is used instead of a wide tire assembly. At a uniform wander mode, rut depth increases by 0.2 mm for every 10 km/h decrease in traffic speed within 90 km/h to 70 km/h range.

Open access