Browsing by Issue Date, starting with "2011"

Now showing 1 - 20 of 689

Access status: Open Access ,
Modelling of amplitude-selective-damping valves
(2011) Gołdasz, Janusz P.
The so-called amplitude-selective-damping (ASD) valving is a relatively new approach for modifying the output of a hydraulic shock absorber. In the automotive industry ASD valves are known to improve isolation from road inputs. During more aggressive maneuvers the systems maintains the performance of a standard (non-ASD) shock absorber. In the paper, the author derives and analyzes a fairly complete state-space model of an exemplary piston-side ASD valve. The model includes key geometric and performance characteristics of the valve. The results are shown in the form of phase plane plots of force-displacement diagrams, respectively, for a twin-tube shock absorber configuration of choice.
Access status: Open Access ,
A new composition theorem for Sp-weighted pseudo almost periodic functions and applications to semilinear differential equations
(2011) Zhao, Zhi-Han; Chang, Yong-Kui; N'Guérékata, G. M.
In this paper, we establish a new composition theorem for $S^p$-weighted pseudo almost periodic functions under weaker conditions than the Lipschitz ones currently encountered in the literatures. We apply this new composition theorem along with the Schauder's fixed point theorem to obtain new existence theorems for weighted pseudo almost periodic mild solutions to a semilinear differential equation in a Banach space.
Access status: Open Access ,
Zmienność litologiczna osadów ilasto-krzemionkowych z obszaru IOM (strefa rozłamowa Clarion-Clipperton; E Pacyfik)
(Wydawnictwa AGH, 2011) Maciąg, Łukasz; Kotliński, Ryszard A.; Borówka, Ryszard K.
Authors presented geospatial variability of selected sedimentological, mineralogical and diagenetical features of clayey-siliceous sediments from Interoceanmetal deposit area (eastern Pacific, Clarion-Clipperton fracture zone). Changes of environmental conditions essential to geological and palaeogeographical situation into C-C zone, and also their importance to forming processes of Fe/Mn oxide concentrations have been described. Research studies on sediments, classified to the uppermost part of Clipperton FCl IV Formation (pliocene-holocene), show unimodal distribution of samples, poor sorting and mean grain size of siliceous clayey muds amount to x = 6,83 phi. Some qualitative/quantitative changes into the mineral composition of the clay 0,004 / 0,002 mm subfractions (clay minerals from kaolinite/illite/chlorite/smectite groups), perpendicular variability of some Radiolaria/Diatomeae species and also micronodules amount depletion during burial processes have been confirmed. Environmental conditions into the C-C zone enable to form economically attractive depositional fields covered by polymetallic nodules that constitute potential ore sources of Mn, Ni, Co, Cu and other metals in the future.
Access status: Open Access ,
PDC single cutter : the effects of depth of cut and RPM under simulated borehole conditions
(2011) Majidi, Reza; Miska, Stefan; Tammineni, Sandeep
While the weight on bit (WOB) and rotary speed (RPM) are perhaps the most important drilling parameters affecting the rate of penetration, limited information are available about the fundamental mechanisms of rock destruction and the effect of cutting speed and the depth of cut during the cutting process. Experiments were carried out in a high-pressure facility with a 13 mm single PDC cutter to cut Carthage Marble and Indiana Limestone samples with depths of cut in the range of 0.02-0.12 inch and rotary speeds from 30 to 180 RPM at atmospheric and pressurized conditions. Our previous experimentations showed that an increase in the confining pressure as small as 150 PSI could significantly increase the Mechanical Specific Energy (MSE) of the cutting process and reduce the efficiency by half. Recently performed atmospheric and pressurized single cutter tests, showed that a minimum depth of cut was required to efficiently drill the rock samples. MSE required to cut the rock, reached a minimum at depths of cut greater than 0.08 inches for both Indiana Limestone and Carthage Marble samples. Most promising were the results that showed a decrease in MSE at high rotational speeds (RPM 100) and atmospheric pressure, possibly indicating a change in rock failure mechanism. A mathematical model was derived from the balance of forces acting at the PDC cutter that constitutes a single linear relation between the cutting force and the normal force. The characteristic line acts as an indication of bit-rock interaction and can be used to detect the formation and cutter dullness. The model was verified using the experimental data from the single cutter tests. Such observations and analysis provide useful insights into the physics of cutter-rock interaction and are valuable to the improvements of drilling practices selection (WOB, rotary speed, etc) and the rates of penetration.
Access status: Metadata only ,
Organizacja morskich badań geofizycznych na przykładzie projektu »BalticPipe«
(Wydawnictwa AGH, 2011) Hac, Benedykt; Gajewski, Juliusz; Gajewski, Lucjan; Nowak, Jarosław Robert; Szefler, Kazimierz
Exploration of raw minerals on sea bottom using specialised research vessels, equipped in devices (multibeam echosounders, side scan sonars, subbottom profilers, etc.) for geophysical investigations, in its organizational aspects does not essentially differ from other activities aimed at investigation of surface sea bottom sediments. This information concerning sea bottom is also necessary for preparatory work before laying pipelines, power and telecommunication cables, and building hydraulic engineering constructions. The organization of geophysical investigations in the sea named in the title of the paper, aimed at gaining knowledge on sea bottom structure along a planned pipeline, is a good tool to demonstrate the way how to prepare and to carry out exploration of raw materials on the sea bottom, using acoustic methods.
Access status: Open Access ,
Możliwości wykorzystania Dolnej Wisły do celów transportowych
(Wydawnictwa AGH, 2011) Bolt, Adam; Jerzyło, Patrycja
The water transport is cheapest, safest and least troublesome for the natural environment. Restoring the regular goods navigation will result behind himself in the revitalization existing and construction of new infrastructure handling-logistic of inland commercial ports. Creating the transport policy, it is necessary to remember that the water transport is the most ecological type of transport. He is producing the 10% of the emissions of gases expelled to the atmosphere by the equivalent wheeled transport scarcely. His energy consumption is a 30% of the energy consumption of the wheeled transport. A characterization of the Lower Vistula was included in the article, concept of development of the watercourse at the part Bydgoszcz - Gdańsk. Barriers hindering the development of the water transport and argumentation speaking for the activation of watercourses in Poland are presented. An alternative transport was described for carriages of cargo overland. The Lower Vistula constitutes the very important length for the inland waterway shipping. He constitutes the part of international E40 watercourses and E70 as well as Gdańsk and Gdynia can fulfill the transport important function for bulk goods or in containers at the part from the center of Poland to ports. The presented watercourse of the Vistula, as the chain in the all-Polish transport network with using container terminals on existing wharves in the Port Gdańsk and with new terminal in Bydgoszcz.
Access status: Open Access ,
Analiza przemieszczeń poprzecznie obciążonej grupy pali w ośrodku liniowo sprężystym o cechach losowych
(Wydawnictwa AGH, 2011) Bauer, Jerzy; Puła, Wojciech; Wyjadłowski, Marek; Schleiss, Monika
A probabilistic analysis of limit serviceability state of a pile groups is presented in the paper. Pile heads are interconnected and loaded by a horizontal force. Interaction of piles and subsoil is modelled by a set of springs using classical method called Kx generator. Applying the response surface method for the displacement data calculated from the resulting static model, the reliability indices and sensitivity coefficients are computed for assumed variability of random Young's modulus and random thickness of upper soil layer.
Access status: Open Access ,
Modelowanie numeryczne stanu naprężenia w sąsiedztwie przodka wyrobiska ścianowego z uwzględnieniem obecności metanu
(Wydawnictwa AGH, 2011) Florkowska, Lucyna; Walaszczyk, Jan
Knowing the state of stress within rock mass near the exploitation area is a crucial element of planning mining works, especially in areas containing methane, which often happens in case of coal exploitation. One of the solutions to this problem is numerical modeling. This paper presents a method of estimating the changes of the state of stress around long wall exploitation area, based on MES numerical simulation. Mathematical model used here, treating coal as porous compressible medium, considers the presence of methane within rock mass and its flow caused by exploitation. It allows to observe both the changes of the state of stress and of methane porous pressure within rock mass. The results obtained were compared to the results of methane pressure tests available in literature.
Access status: Open Access ,
Decorative layers on silicon bronzes
(2011) Muskała, Karolina; Nadolski, Maciej; Derda, Anna
Decorative coatings artificially obtained on the surfaces of copper castings, commonly called artificial patinas in opposition to natural patinas, allow for adjusting the colour, the gloss, and the colour intensity of a casting to the customer demands. A decorative coating is a part of the artistic casting and the key element to the impression exerted by a sculpture. The colour, the type, and quality of a decorative coating depend on the author's intention, so that an artistic foundry should deal successfully with a variety of demands. Beside exerting the strictly artistic impression, patinas have one more goal to achieve - it is the corrosion protection. Natural patinas arising nowadays are characterised by Iow quality, irregular thickness, numerous cracks, and the dull taupe-brown colour. Therefore there exists need of generating decorative coatings in a controlled way. The present work is aimed to determine the influence of mechanical abrasive working applied to the surfaces of BK331 silicon bronze castings on the quality and durability of the obtained decorative coating for given recipes for patinating solutions.
Access status: Open Access ,
Concept of production facilities layout in company Alumin, s.r.o. Slovakia
(AGH University of Science and Technology Press, 2011) Straka, Martin
The aim of part of the solution layout processing company is an analysis of the existing system of distribution of production equipment company, identification of material flows and showing the possibility of modifying the layout of production facilities in compliance with capacity, safety and quality requirements for production.
Access status: Open Access ,
Small and low-cost mobile mapping systems
(2011) Kolecki, Jakub
Nowadays acquisition of large amount of data for various mapping applications like creation of a terrain, building or a building part models is performed mainly using laser scanners or photogrammetric methods. From early nineties we observe more intensive development of a mobile mapping systems integrating various types of cameras not only with positioning systems like GPS, but also with inertial measurements units (IMU) and other geo-referencing sensors. Such mobile mapping devices have obviously very high prices, are large-sized and have usually very high weight. There are however some lightweight constructions basing on alternative solutions other then those met in expensive commercial systems. The researches conducted among many institutions in the world show that such systems may be in fact constructed using relatively inexpensive devices, available on the market. The accuracy demands could be satisfied for a bulk of mapping applications. This paper addresses the topic of low-cost mobile mapping systems. First of all a few examples of such systems will be presented, and then more detailed overview of geo-referencing technologies will be given.
Access status: Open Access ,
Wyznaczanie wartości naprężeń poziomych wokół wyrobisk górniczych za pomocą metody różnicy azymutów
(Wydawnictwa AGH, 2011) Pawelus, Daniel
The paper presents the azimuths difference method. This innovative method can be used to estimate numerical quantity of the perpendicular and parallel horizontal stress around underground excavations. The azimuths difference method has importance for the process of improvement of mining support stability. In situ stress measurements and horizontal stress field in the Rudna mine were described. Calculations of the horizontal stress were carried out for underground excavations in the »Rudna Północna« mining region by the azimuths difference method.
Access status: Open Access ,
Analiza przestrzenna wzbogacalności popiołożużli z wykorzystaniem metod geostatystycznych
(Wydawnictwa AGH, 2011) Namysłowska-Wilczyńska, Barbara; Skorupska, Bożena; Wieniewski, Andrzej
Spatial analyses were carried out to develop a 3D geostatistical model of the spatial variation in the technological parameters of an ash-slags heap connected with the operation of the power utilities located near Świecie (Toruń). Tank A filled with ash-slags was the subject of geostatistical studies. The spatial variation of recoverability e' (defined as the amount of carbon kg recovered from 1 ton of ash- slags), was analyzed. The variation of these parameters in the horizontal and vertical extents of the ash-slags heap was subjected to structural (variographic) analysis using the directional variogram function. The parameters of geostatistical models approximating the directional variogram recoverability e' were the basis for the estimation. Averages Z* and corresponding standard estimation deviations delta/k were estimated for the particular depths of the tank using (3D) ordinary (block) kriging. Thanks to the application of the geostatistical methods to describe the parameters of the waste material (treated as an anthropogenic deposit) databases containing complete valuable input information for a project aimed at utilizing the deposited material were created.
Access status: Open Access ,
Transport wody rurociągami szybowymi w instalacjach chłodzenia powietrza w podziemnych wyrobiskach górniczych
(Wydawnictwa AGH, 2011) Filek, Krzysztof
A control of thermal hazard in underground mines is connected with cooling equipment utilization, Heat received from cooled air in excavations can be used on a surface. This article applies to problem of warm water transport from mine, with special consideration its pressure and temperature. The algebric equations of pressure distribution were shown and differential equations of temperature distribution in water lines were derived. Two numerical examples, which represented discussed problem, were solved - their results were presented in form of diagrams in two pictures.
Access status: Open Access ,
Wpływ energii formowania na kształt kolumn wykonywanych metodą wymiany dynamicznej
(Wydawnictwa AGH, 2011) Kanty, Piotr; Kwiecień, Sławomir
Driven stone columns formed with the use of dynamic replacement method is one of many geoengineering methods, widely used to strengthen the cohesive and/or organic soils under the linear and cubature objects. It is based on ramming of the aggregate into weak soil using drops of high energy in the specified grid of points. Despite apparent simplicity, the method may pose some problems in practice. They may be caused by inadequate choice of the drop energy during the soil reinforcement which influences the diameter and the length of the columns. In extreme cases the columns may be too short or there may appear a total soil replacement. For these reasons the authors of the paper decided to carry out a series of laboratory tests which aimed at determining the influence of the drop energy on the shape of the columns. The research was carried out on the test stand that allowed the observation of the formation process of a rammed column. Its dimensions were adjusted so as to reflect the real dimensions in scale 1:10. In order to carry out the observations of the processes intervening during the rammed column formation the experiments were filmed and photographed. Three following variations of reinforcement were analysed: by using a relatively constant but low (column z. 2), constant and maximal in the carried research (column z. 3) and gradually increasing (column z. 1) energy. The obtained columns differed in shape. The whole is preceded by a short information about the dynamic replacement method.
Access status: Open Access ,
Geotourism during excursions in the northeastern part of The Gorce National Park
(2011) Tyrkiel-Barmuta, Maria
The Gorce Mountains National Park is located on the southern part of the Małopolska Province in Poland. Despite the lack of spectacular geological attractions it is a very good site to promote Earth Sciences knowledge and especially to educate in geology. The example of the on-day excursion going along the touristic trails within The Gorce Mountains National Park is being described in the presented paper. The author described great diversity of the geological and geomorphological elements, presenting educational values.
Access status: Open Access ,
The possibilities and chances of the Project Energy Complex Kovin - new coal mine and power plant
(Wydawnictwa AGH, 2011) Radunović, Milan; Kecman, Obrad; Mihajlović, Tanja; Schlenstedt, Jörg; Denke, Peter; Đurić, Dušan
Project Energy Complex Kovin refers to future coal mining and power plant construction. Coal from a Kovin deposit is in all parameters of quality suitable for burning in power plants and commercial use. Over the past 15 years in the »unprotected« part of the deposit there is a test pit with an experimental underwater coal mining method to collect data and examine the possibilities of this method in large-scale and reserves adequate for the construction of power plants. This paper presents the activities, activities that are in progress and highlights of the project.
Access status: Open Access ,
Surowce mineralne oceanów
(Wydawnictwa AGH, 2011) Piestrzyński, Adam
The work consists of a mineral deposits characteristics occurring in the World Ocean, based on genetic classification. The following type of the mineral deposits have been discussed: sedimentary biogenic, chemical, and placer as well as hydrothermal types. Localization and an economic importance of all deposits types listed in the text has also been presented.
Access status: Open Access ,
Problemy właściwej interpretacji wyników analiz układów konstrukcja-podłoże gruntowe
(Wydawnictwa AGH, 2011) Fedorowicz, Lidia; Fedorowicz, Jan; Kadela, Marta
In this paper description of the structure-subsoil systems concern their numerical behaviour obtained in basic engineering models during progressive failure process: - for the whole system structure-subsoil, or only - for structure that co-operates with subsoil. The above analyses present an attempt to provide an answer to the question - when the numerical calculation model (with the basic Coulomb-Mohr constitutive description) assure adequate evaluation of a hazard for: 1) loss of bearing capacity for the whole system structure-subsoil; with mode of failure, 2) progressive rigidity degradation of the road structure co-operating with subsoil; where the progressive failure, durability and load capacity are directly connected.
Access status: Open Access ,
Scheduling jobs with linear model of simultaneous ageing and learning effects
(2011) Janiak, Adam; Lichtenstein, Maciej; Rusoń, Agata
In the paper, we introduce some new scheduling model in which learning and aging effects are both considered simultaneously. In this model the actual processing time of the jobs depends only on its position in a schedule and can be described by the piecewise linear function. For single-processor problem with introduced model, we show that the problem of minimizing the makespan criterion for independent jobs with release dates is strongly NP-hard, but some special cases of this problem are polynomially solvable. Based on those special cases, we propose 4 heuristic algorithms and we experimentally examine their usefulness for solving the general problem.