Browsing by Issue Date, starting with "2011"

Now showing 1 - 20 of 685

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 ,
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 ,
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 ,
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.
Access status: Open Access ,
Porównanie postaci konstrukcyjnych koła zabierakowego pojazdów koparki wielonaczyniowej
(Wydawnictwa AGH, 2011) Rusiński, Eugeniusz; Smolnicki, Tadeusz; Przybyłek, Grzegorz
Driving centres of surface mining crawlers are high loaded elements. These elements are also strongly abraded. Therefore the mining machine requires frequent replacement of the wearied elements. Driving centre should allow for such replacement, and also meet certain strength requirements. Three versions of the wheel drive mechanism of the Bucket Wheel Excavator have been presented. Geometric forms of various construction solutions have been also shown in the paper. Apart from this, boundary conditions have been identified to carry out the numerical analysis with the use of FEM. Finally, advantages and disadvantages of proposed solutions have been presented.
Access status: Open Access ,
The Ngorongoro Crater as the biggest geotouristic attraction of the Gregory Rift (Northern Tanzania, Africa) - geological heritage
(2011) Żaba, Jerzy; Gaidzik, Krzysztof
The Ngorongoro Crater is the largest unflooded and not destroyed collapse volcanic caldera of the shield volcano on Earth. It attracts many visitors each year not only because of the undoubted wealth of the wildlife and breathtaking views, but also due to the geotouristic attractiveness of this definite location. The Crater is in fact a specific example of geological processes, relevant to the development of planet Earth. In a relatively small area one can observe rocks of different types and ages: Precambrian igneous and metamorphic rocks, volcanic rocks formed in the Pliocene, Pleistocene, and even nowadays, as well as sedimentary rocks, up to those currently forming within the caldera floor. The origin and development of the Ngorongoro volcano, and lately caldera, is closely related to the activity ofrifting processes occurring along the Gregory Rift, belonging to the East African Rift System. It represents one of the three arms of the Afar triple junction associated with the located here hotspot. Due to the geotouristic attractiveness, as well as a richness of living nature and archaeological sites with discoveries of our ancestors, which illustrate an important stage in the history of mankind, the area of the Ngorongoro Crater was designated a UNESCO World Cultural and Natural Heritage Site.
Access status: Open Access ,
ISO 19113:2002 with reference to digital terrain models
(2011) Kulesza, Łukasz
The ISO 19113:2002 standard establishes the principles for quantifying the quality of geographic data and specifies components for reporting quality information. It also provides an approach to organizing information about data quality. According to it, the issue of quality is a multifactor problem and includes such elements like: completeness, logical consistency, positional accuracy, temporal accuracy, thematic accuracy. Its principles are applicable to digital geographic data, however they can be extended to many other forms of geographic data such as maps, charts and textual documents. For data users it answers a crucial question whether or not specific geographic data is of sufficient quality for their particular application. Additionally it may be used for describing quality requirements. Digital Terrain Models (DTM) are a very important information layer in GIS applications. Multiple spatial analyses are being held with the usage of DTM starting from simple queries, through map analysis derived from DTM: slope and aspect maps and finally finding application in complex modelling of environmental phenomenon. Recently more and more attention is paid to the GIS analysis credibility, which makes the quality issues and data sets accuracy more important then ever. Owing to fact that quality is an extensive concept, one criterion assessment cannot be applied to every possible situation. Domain of the problem as well as the goals of specific application need to be recognized and the acquired knowledge must be confronted with the information regarding possessed data. It is in connection with the reliability and fitness to use issue which states that every certain DTM is appropriate only for some set of applications, and the user must be aware of that. It is important for the user to have the sense of purpose. Whether a DTM is of sufficient quality for particular application depends on the data itself and on the purpose of its usage. In current work an attempt was made to discuss the issues regarding DTM quality in the light of guidelines included in ISO 19113:2002 Standard. Practical example of quality assessment of few chosen DTM obtained from different sources was introduced.
Access status: Open Access ,
Existence and uniqueness theorem for a Hammerstein nonlinear integral equation
(2011) Khachatryan, A. Kh.; Khachatryan, Kh. A.
The existence of a solution, as well as some properties of the obtained solution for a Hammerstein type nonlinear integral equation have been investigated. For a certain class of functions the uniqueness theorem has also been proved.
Access status: Restricted ,
Materiały do ćwiczeń projektowych z budownictwa ogólnego
(Dolnoślaskie Wydawnictwo Edukacyjne, 2011) Schabowicz, Krzysztof; Gorzelańczyk, Tomasz
Access status: Open Access ,
Influence of drilling direction on wellbore stresses
(2011) Knez, Dariusz; Megao, Eddie; Knez, Janusz; Śliwa, Tomasz
The transposed in-situ stress state relative to the borehole coordinate system (Cartesian borehole coordinate system) and the total stress component at the borehole wall (cylindrical coordinate system) exhibits cyclic behaviour with respect to drilling direction of borehole with respect to delta/H, Beta. On the other hand, with varying borehole inclination, a, the stress either increases or decreases with increasing a angles. Consequently the effective maximum, delta1 and average, delta2 principal stresses exhibits the same behaviour. It can be concluded generally that the effective principal stress state of a wellbore would vary in a cyclic behaviour and would have a maximum and minimum stress points. From these observations, it is obvious that in any situation, optimal combinations of alpha and Beta will have to be established before drilling is commenced in order to optimise stability of the borehole.
Access status: Open Access ,
The equality case in some recent convexity inequalities
(2011) Maksa, Gyula; Páles, Zsolt
In this paper, we investigate a functional equation related to some recently introduced and investigated convexity type inequalities.