Browse

21 - 30 of 97 items :

  • Energy Engineering x
  • Engineering x
  • Introductions and Overviews x
Clear All
Evaluation of Pile’s Buckling Under Axial Load by B-Spline Method and Comparison With Finite Element Method and Exact Solution

Abstract

Although various analytical and numerical methods have been proposed by researchers to solve equations, but use of numerical tools with low volume calculations and high accuracy instead of other numerical methods with high volume calculations is inevitable in the analysis of engineering equations. In this paper, B-Spline spectral method was used to study buckling equations of the piles. Results were compared with the calculated amounts of the exact solution and finite element method. Uniform horizontal reaction coefficient has been used in most of proposed methods for analyzing buckling of the pile on elastic base. In reality, soil horizontal reaction coefficient is nonlinear along the pile. So, in this research by using B-Spline method, buckling equation of the pile with nonlinear horizontal reaction coefficient of the soil was investigated. It is worth mentioning that B-Spline method had not been used for buckling of the pile.

Open access
Experimental Evaluation of the Effect of Water-Cement Ratio on Compressive, Abrasion Strength, Hydraulic Conductivity Coefficient and Porosity of Nano-Silica Concretes

Abstract

Dams are considered as strategic structures due to their initial role in economic system of the country, therefore, they are expected to be fully functional and powerful. Nano technology could be an effective factor of abrasion and compressive strength, porosity and hydraulic conductivity coefficient of the concrete, thus more scientific research is essential to be carried out on these types of concrete due to their quite modern and high technology. In the current study, the effects of water-cement ratio on compressive and abrasion strength, porosity and hydraulic conductivity coefficient of concrete was investigated. The constructed concrete samples with 4% Nano-silica and water-cement ratios of 0.35 to 0.55 were tested. Other design features remained fixed in all concrete samples. The compressive strength of block samples of 150×150×150 mm were assessed in terms of time lasting 7, 28 and 90 days. The abrasion strength of the identical block samples were tested after 28 days. The hydraulic conductivity coefficient of cylindrical shape samples with the diameter 150 mm and height of 300 mm were experimented after 28 days. The results of the experiments indicated that by reducing the water-cement ratio from 0.55 to 0.35, the compressive strength increased 37.13, 40.14 and 38.22% for 7, 28 and 90 days age samples respectively and abrasion strength of concrete increased 38.22% and the hydraulic conductivity coefficient (m/s) and depth of penetration (mm) of the concrete decreased from 27.76×10−15 and 2.756 to 1.5×10−15 and 0.784 respectively. In addition porosity decreased from 12.76 to 11.22%.

Open access
LOD2 Building Generation Experiences and Comparisons

Abstract

The VOLTA project is a RISE Marie-Curie action designed to realize Research & Innovation (R&I) among intersectoral partners to exchange knowledge, methods and workflows in the geospatial field. To accomplish its objectives, the main R&I activities of VOLTA are divided in four interlinked Work Packages with two transversal ones responsible for knowledge transfer & training as well as dissemination of the project results. The research activities and knowledge transfer are performed with a series of secondments between partners. The consortium is composed of 13 partners from academic & research institutions, industrial partners and national mapping agencies. The Romanian National Center of Cartography is part of this research project and in this article the achievements of the secondment at Bruno Kessler Foundation in Trento (Italy) are given. The main goal of the exchange was to generate level of detail - LOD2 building models in an automated manner from photogrammetric point clouds and without any ancillary data. To benchmark existing commercial solutions for the realization of LOD2 building models, we tested Building Reconstruction. This program generates LOD2 models starting from building footprints, digital terrain model (DTM) and digital surface model (DSM). The presented work examined a research and a commercial-based approach to reconstruct LOD2 building models from point clouds. The full paper will report all technical details of the work with insight analyses and comparisons.

Open access
Mining Activity and its Remains - The Possibilities of Obtaining, Analysing and Disseminating of Various Data on the Example of Miedzianka, Lower Silesia, Poland

Abstract

The article presents comprehensive documentation of the situation of post-mining Miedzianka village (former town), which is located in Lower Silesia, in south-western Poland. Due to the long-term expansive mining exploitation since the 14th century, over time Miedzianka was completely destroyed and depopulated, thus nowadays, only a few inhabitants live there. The basis for the conducted research area were changes in land and urban structure that have been occurring for centuries in connection with mining operation of copper and uranium. The authors focused on presenting the changes using archival cartographic documentation, land surveying measurements and 3D modelling. That data allowed to determine on the ground specific sites related to mining operations, discover old urban buildings, performing their 3D models and finding places potentially threatened by continuous and discontinuous deformations. The combination of all the data allowed to present the full situation that occurred in Miedzianka.

Open access
A Review of Fiber Synergy in Hybrid Fiber Reinforced Concrete

Abstract

Fibre reinforced concrete (FRC) presently utilized as a part of special structures subjected to dynamic loads for example airport pavements, expressways overlays, bridge decks and machine foundations. In most cases, FRC contains just a single kind of fibre. The utilization of at least two kinds of fibres in an appropriate mix can possibly improve the mechanical properties of concrete and result in performance synergy. The audit demonstrates that the blend of fibre allows a more powerful control of the dynamic crack development. This review analyses the components for synergistic impacts that gives direction on the fiber and matrix choice.

Open access
Updating Geospatial Data by Creating a High Resolution Digital Surface Model

Abstract

Smart Cities are no longer just an aspiration, they are a necessity. For a city to be smart, accurate data collection or improvement the existing ones is needed, also an infrastructure that allows the integration of heterogeneous geographic information and sensor networks at a common technological point. Over the past two decades, laser scanning technology, also known as LiDAR (Light Detection and Ranging), has become a very important measurement method, providing high accuracy data and information on land topography, vegetation, buildings, and so on. Proving to be a great way to create Digital Terrain Models. The digital terrain model is a statistical representation of the terrain surface, including in its dataset the elements on its surface, such as construction or vegetation. The data use in the following article is from the LAKI II project “Services for producing a digital model of land by aerial scanning, aerial photographs and production of new maps and orthophotomaps for approximately 50 000 sqKm in 6 counties: Bihor, Arad, Hunedoara, Alba, Mures, Harghita including the High Risk Flood Zone (the border area with the Republic of Hungary in Arad and Bihor)”, which are obtained through LiDAR technology with a point density of 8 points per square meter. The purpose of this article is to update geospatial data with a higher resolution digital surface model and to demonstrate the differences between a digital surface models obtain by aerial images and one obtain by LiDAR technology. The digital surface model will be included in the existing geographic information system of the city Marghita in Bihor County, and it will be used to help develop studies on land use, transport planning system and geological applications. It could also be used to detect changes over time to archaeological sites, to create countur lines maps, flight simulation programs, or other viewing and modelling applications.

Open access
The Use of Laser Scanning and Unmanned Aerial Vehicles in Construction Surveying in the Light of Legal Regulations in Poland

Abstract

Construction surveying consist in overall surveying works performed at every stage of the construction and use of a building structure. The surveyor participates in the processes of designing, direct implementation, maintenance and use, as well as demolition of a building structure. Advanced surveying techniques, such as laser scanning and UAV photogrammetry, are being increasingly used to perform the surveyor’s tasks. The aim of this research paper was to analyze the Polish legal regulations for the possibilities of applying the above-mentioned techniques to carry out the surveying works which are subject to the obligatory submission to public administration authorities. The primary focus was placed on the type of the works associated with construction surveying. The conducted research studies confirmed the lack of appropriate guidelines that would clearly define the scope and method of using laser scanning and UAV photogrammetry in construction surveying. At the same time, it was demonstrated that both these techniques of spatial data acquisition were sufficiently accurate to perform plane and vertical land surveys pursuant to the legal acts currently in force in Poland, and they can be used at selected stages of construction surveying. Finally, the authors proposed some solutions that would make it easier for the surveyors to use laser scanning and UAV photogrammetry in standard surveying works.

Open access
Using Cuttlebone Powder to Produce Green Concrete

Abstract

Limestone has been commonly used in concrete for several decades. Moreover, calcium carbonate was used as a portion of cement content. Therefore cuttlebone powder, which is composed of a naturally occurring crystal form of calcium carbonate named aragonite, was used in concrete as a substitution of a portion of cement content in this research program for the first time. It led to the production of green concrete which is a type of concrete causes less harm to environment. 3, 5 and 7 percent of cement were substituted with cuttlebone powder. For this purpose, 4 concrete mix designs included 36 cubes, 4 cylinders and 4 prisms were casted. Results showed that weight of the specimens with cuttlebone powder was lower than control specimen. Moreover, by adding cuttlebone powder to concrete, slump increased. Although compressive and tensile strengths of the specimens with cuttlebone powder were lower than control specimen, but the specimen with 3% cuttlebone powder had adequate strength. Besides, three-point flexural strength of the concrete with 3% cuttlebone powder was higher than control specimen. It seems that by reducing water content of the specimen with cuttlebone powder to have similar slump to the control specimen, better performance of concrete can be achieved. So, this natural material can be used instead of a portion of cement to produce green concrete.

Open access
Air Exchange Rate in Air Quality Assurance – A Case Study

Abstract

The goals of this paper are to estimate some parameters – indoor temperature and ventilation rate - necessary to determine the heat load demand for ventilation in the amphitheatre named ‘A TALPOSI’-Faculty of Buildings Engineering- with a number of at the most 120 occupants. The study presented in this paper is made when in the amphitheatre it is necessary to assure a comfortable temperature by a permanent functioning of the heating system. The number of air exchanges necessary in the amphitheatre in the natural ventilation process, more exactly, to assure a minimum air exchanges, is imposed by the requirements for the assurance of physiologic comfort in the amphitheatre for the time interval when it is occupied by students. The inner air debit should cover the harmful emissions in the amphitheatre. By the help of these calculated (measured) parameters we have calculated the heat load for ventilation. In the end, with the data obtained from calculations and measurements we find ourselves in the situation of establishing the size of the heat exchanger corresponding to the room, to heat the fresh air taken from outside and send it inside the amphitheatre. The measurements are made with the TESTO apparatus of the faculty. The minimum requirements to assure the thermal comfort are: to achieve a minimum internal temperature θi (t) higher than (or equal to) the normal indoor temperature associated to this space and to assure the air quality, the air exchange rate. The authors want to highlight by this study the necessity and importance of the control on the number of air exchanges in rooms with a high number of occupants and overall, the control of the fresh air debits. The fact that the focus is more and more on heat loss cuts in rooms by tightening closing elements gives birth to the necessity of control of the ventilation system with effects on the consumption of mechanical energy.

Open access
Control and Optimization Against Earthquake by Using Genetic Algorithm

Abstract

In this paper, controlling and optimizing against the earthquake by using genetic algorithm is investigated. In this paper, a new approach for selecting optimal accelerograph and scaling them for dynamic time history analysis is presented by the binary genetic algorithm and natural numbers, in order to achieve the mean response spectrum, which has a proper matching and a short distance with the target spectrum and indicates the expected earthquake of the site. Because of the difference in the nature of accelerograph and the scale coefficients, the genetic algorithm presented in this paper, is hybrid (has two chromosomes). The proposed algorithm is capable of constructing a new generation of people from a series of infinitesimal earth movement records, in a process where natural selection, mating, mutation takes place, and creates a new generation of people and continues this process until a person with desirable qualities is obtained. One of the most important factors in the accuracy and efficiency of these programs is the correct estimation of their parameters. If these parameters are correctly calculated, the difference between the mean response spectrum and the spectrum of the plot will be greatly reduced. Due to the relatively large number of these parameters, the use of trial and error-based methods largely relies on user skills, the proposed hybrid genetic algorithm program can overcome this defect. The program has two genomes that run simultaneously and provide close answers to the optimal answer. The program itself is able to provide the user with a range of optimal coefficients and crossing values and mutations of each chromosome.

Open access