bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cementing Light & Tight: A CBM Cementing Story
Authors: Kumar Animesh , Kumar Anjani 
Published: November 2013

Abstract
The CBM process is an amalgam of oilfield and coal-mining practices that have merged and often require the investigation of parameters that were previously ignored. Production of coal bed methane (CBM) in a short time has become an important industry, providing an abundant, clean-burning fuel in an age when concerns about pollution and fuel shortages preoccupy the thoughts of many Indians.
This paper excerpts the successful use of high strength & low density cement slurry used for primary and remedial cementing jobs in Coal Bed Methane wells in the Raniganj block of Eastern India.
Cement is placed as a sheath across coal seams in coal bed methane wells primarily for hydraulic isolation and to support the casing. Designing a cement job for coal seam wells requires contemplating factors beyond those considered in cementing conventional oil & gas wells.
The successful cementing job in coal seams faces several challenges, viz. cement invasion into coal seams, losses during jobs, low fracture gradient and low formation temperature. Since, most of the CBM wells need to fracture the cement sheath between casing and formation, thus the set cement should not only have high compressive strength, but high tensile strength as well.
The unique advantages of high strength & low density cement slurries are: Reduced density to take care of low fracture gradient of coal seams.Prevent invasion and loss circulation.Eliminate the need for stage cementing.High compressive strength.
The paper also explains the importance of flush-type spacer for better hole cleaning. It is also be used to cure loss circulation zones.
This paper shares case histories and best practices developed for successful cementing operations in CBM wells; and experience of designing, simulating and real time data acquisition.
With the application of real time data acquisition, downhole ECDs (equivalent circulating densities) of fluids can be monitored and kept in check.
A General Model to Monitor the Risk of a Failure to a Means of Transport in Service
Authors: Tomaszek Henryk , Kaleta Ryszard , Zieja Mariusz 
Published: November 2013

Abstract A model to monitor the risk of a failure/damage (undesirable event) to a means of transport has been outlined in the paper, with findings presented in [2] applied. Destructive processes such as the wear-and-tear, fatigue, and ageing, which arise in the course of the system’s (here: the means of transport) service are most fundamental factors that make health/maintenance status thereof deteriorate. A relationship that describes the probability of an undesirable event (failure) against the system’s service life has been formulated. The rate at which undesirable events may occur, i.e. the failure rate, has also been defined. What results from derived relationships is the statement that failure rates are functions of time the system remains in service. With the permissible risk level assumed, there is a chance to determine the permissible time of failsafe operation.
Pulsacje napięcia wyjściowego jako źródło informacji diagnostycznych o komutatorowych prądnicach prądu stałego
Authors: Gębura Andrzej , Radoń Tomasz 
Published: November 2013

Streszczenie W pracy omówiono wybrane problemy eksploatacyjne komutatorowych prądnic prądu stałego. Omówiono pewne aspekty komutacji oraz wpływ zjawisk fizycznych na kształtowanie się składowej pulsacji napięcia wyjściowego komutatorowych prądnic prądu stałego. Składowa pulsacji jest wypadkową wielu zjawisk fizycznych, w związku z tym - zgodnie z wiedzą zawartą w literaturze specjalistycznej - jest rozdzielana na kilka składowych. Omówiono każdą z nich, systematyzując dostępną w literaturze wiedzę teoretyczną, jednocześnie weryfikując ją z wynikami własnych badań laboratoryjnych. Szczególną uwagę zwrócono na zjawiska komutacji - omówiono objawy nieprawidłowości, możliwości ich wykrywania i przeciwdziałania. Omówiono również pewne zjawiska towarzyszące zmianom w charakterze pulsacji podczas zwarć lub przerw w uzwojeniach w tworniku lub stojanie - wskazano na możliwość diagnozowania tych elementów prądnic za pomocą analizy parametrów składowych pulsacji.
Możliwości diagnozowania systemów nawigacji inercjalnej na bazie analizy wartości błędów Schulera
Authors: Szelmanowski Andrzej 
Published: November 2013

StreszczenieW artykule omówiono błędy czujników inercjalnych wykorzystywanych w systemach odniesienia kursu i pionu AHRS (ang. Attitude and Heading Reference Systems) i systemach nawigacji inercjalnej INS (ang. Inertial Navigation Systems) w zakresie prędkości kątowych i przyspieszeń liniowych. Przedstawiono zależności matematyczne określające ich wpływ na błędy wyliczanych parametrów pilotażowo-nawigacyjnych (takich jak prędkości liniowe i współrzędne pozycji nawigacyjnej) obrazowanych m.in. w nahełmowych systemach celowniczych. Przedstawiono problemy diagnozowania systemów nawigacji inercjalnej, zarówno tych najnowocześniejszych (np. centrali TOTEM-3000 z czujnikami laserowymi, stosowanej na śmigłowcu W-3PL GŁUSZEC), integrowanych na bazie cyfrowej szyny danych MIL-1553B lub ARINC-429, jak i „starszych” rozwiązań konstrukcyjnych (np. układów IKW-1 i IKW-8 stosowanych na samolotach Su-22). Podano metody badań torów przetwarzania sygnałów z czujników inercjalnych oraz wytyczne dla komputerowego systemu oceny stanu technicznego systemów nawigacji inercjalnej z przedłużanym resursem technicznym.
Feasibility to Diagnose Inertial Navigation Systems Through Analysis of Schuler Errors
Authors: Szelmanowski Andrzej 
Published: November 2013

Abstract The paper is intended to discuss errors in measurements of angular velocity and linear acceleration by means of electronic inertial sensors incorporated into the Attitude and Heading Reference Systems (AHRS) as well as Inertial Navigation Systems (INS). The mathematical equations are found out to establish how these errors affect deviations of flight parameters (such as linear speed and coordinates of the aircraft position indicated by navigation systems) that are calculated from the measurements and imaged e.g. in helmetmounted cueing systems. Some issues related to diagnostics of inertial navigation systems are addressed as well, both the most recent ones (e.g. the TOTEM-3000 central station with laser sensors installed on-board of the W-3PL GŁUSZEC helicopter) integrated via digital data buses MIL-1553B or ARINC-429 as well as more outdated solutions, such as IKW-1 and IKW-8 system used for Su-22 aircrafts. The methods of examination of the data processing paths for signals received from inertial sensors are presented with guidelines for development of the computer system for assessment of technical condition exhibited by systems of inertial navigation with prolonged technical resource.
Diagnostics and Technical Status Monitoring of Electric Fuel Pumps for Aircrafts
Authors: Tokarski Tomasz , Gębura Andrzej 
Published: November 2013

Abstract The paper outlines selected operational problems associated with electric fuel pumps that are indispensable to build-up positive pressure upstream the plunger pump of turbojet engines. Any failure of that electric pump may lead to suction of air into the plunger pump and eventually the engine flameout. Comparison is made between two electric drives for fuel pumps: a three phase 115/208 VG, 400 Hz AC drive and a 26V DC drive. Attention is paid to serviceability of pumps and capacities of the AFIT to diagnose and monitor technical status of electric fuel pumps.
Vision-Guided Control Algorithms for Micro Aerial Vehicles
Authors: Wijaszka Mirosław 
Published: November 2013

AbstractThis study presents an image analysis method used in the vision guided control system for Micro Air Vehicles (MAVs). The paper describes a hypothetical model of a MAV located in the GPS-denied unknown environment, somewhere indoors. The model keeps moving autonomously following ‘the track’ marked with corners and other feature points recorded with a monocular camera pointed at the far end of a corridor and slightly tilted down at the angle β (20° - 30°). The flight stability and control are provided with an on-board autopilot that maintains zero pitch and roll angles and constant altitude. The image analysis has been based on the real-time computer vision library - OpenCV (Open Source Computer Vision library - http://opencv.willowgarage.com).
Numerical Simulation of Underground Mining Exploitation Influence Upon Terrain Surface / Modelowanie Numeryczne Wpływu Podziemnej Eksploatacji Górniczej Na Powierzchnię Terenu
Authors: Tajduś Krzysztof 
Published: November 2013

Abstract
Underground mining exploitation may result in mining damages to building objects located on a terrain surface. Considering high harmfulness of this phenomenon, the scientists from all over the world have tried to describe impact of underground exploitation on deformations of terrain surface and objects located thereon. The first theories, based on the Gaussian distribution, have emerged in the 1950s and are in use until now. Later on, in connection with development of computational techniques, their availability and numerical methods, a possibility of numerical computations use for forecasting of deformations has emerged. These methods, when suitable numerical models are adopted, enable to include higher number of factors influencing the results being obtained. When constructing numerical model, particular attention should be paid on selection of: appropriate geometry of model, proper constitutive model describing behavior of rock and soil layers, adequate values of rock mass parameters prior to execution of mining exploitation, and after it. The author presented in this article part of these problems, based on own experience.
Study of Ground Response Curve (GRC) Based on a Damage Model / Badanie Krzywej Odpowiedzi Gruntu (Grc) W Oparciu O Model Pękania Skał
Authors: Molladavoodi H. 
Published: November 2013

Abstract
Analysis of stresses and displacements around underground openings is necessary in a wide variety of civil, petroleum and mining engineering problems. In addition, an excavation damaged zone (EDZ) is generally formed around underground openings as a result of high stress magnitudes even in the absence of blasting effects. The rock materials surrounding the underground excavations typically demonstrate nonlinear and irreversible mechanical response in particular under high in situ stress states. The dominant cause of irreversible deformations in brittle rocks is damage process.
One of the most widely used methods in tunnel design is the convergence-confinement method (CCM) for its practical application. The elastic-plastic models are usually used in the convergence-confinement method as a constitutive model for rock behavior. The plastic models used to simulate the rock behavior, do not consider the important issues such as stiffness degradation and softening. Therefore, the use of damage constitutive models in the convergence-confinement method is essential in the design process of rock structures. In this paper, the basic concepts of continuum damage mechanics are outlined. Then a numerical stepwise procedure for a circular tunnel under hydrostatic stress field, with consideration of a damage model for rock mass has been implemented. The ground response curve and radius of excavation damage zone were calculated based on an isotropic damage model. The convergence-confinement method based on damage model can consider the effects of post-peak rock behavior on the ground response curve and excavation damage zone. The analysis of results show the important effect of brittleness parameter on the tunnel wall convergence, ground response curve and excavation damage radius.
Evolution of the Structure and Mechanical Strength of a Coal Particle During Combustion in the Atmosphere of Air and the Mixture of Oxygen and Carbon Dioxide / Ewolucja Struktury Oraz Wytrzymałości Mechanicznej Ziarna Węgla Podczas Spalania W Atmosferze Powietrza Oraz Mieszaninie Tlenu I Dwutlenku Węgla
Authors: Pełka Piotr , Golański Grzegorz , Wieczorek Paweł 
Published: November 2013

Abstract
The research was conducted on the basis of four different types of hard coal and one type of brown coal. There are typical coals commonly used as fuel in Polish CFB boilers. The combustion process was conducted at a temperature of 850°C and the atmosphere of ambient air as well as in the mixture of oxygen and carbon dioxide in different proportions. The research was carried out using specially prepared cubical coal particles with measurements of 15×15mm and also 10×10 mm. The change of the mechanical properties was analyzed based on three parameters, i.e. compression strength, Vickers hardness and fracture toughness. The analysis was supplemented by microscopic images of the surface of the particles using an atomic force microscope. The results obtained clearly indicated the mechanical changes of the coal during its combustion, particularly at the moment of ignition of the char. Moreover, the results correlate very well with the processes of coal comminution that have been described by other authors (Basu, 1999; Chirone et al., 1991) during combustion in the circulating fluidized bed and also explain the sudden change of susceptibility to erosion in the conditions with and without combustion. The measured values can be used as strength parameters in the modelling of the mass loss of coal particles in conditions of circulating fluidized bed combustor that are hard to describe.
Estimating Volume of Roof Fall in the Face of Longwall Mining by Using Numerical Methods / Estymacja Objętości Zawału Stropu W Rejonie Przodka Ścianowego W Oparciu O Metody Numeryczne
Authors: Saeedi Gholamreza , Shahriar Korosh , Rezai Bahram 
Published: November 2013

Abstract
Dilution is one of many challenges confronting professionals in mining and milling, and is perhaps one of the oldest. Longwall mining is one of the mining methods that is often affected by out-of-seam dilution (OSD). In this method, roof falls play a significant role in increasing OSD in the prop-free front of the face area. Thus, estimating the volume of roof fall can be extremely helpful to assess dilution of the run of mine coal without a sampling process. This paper presents the effect of exposed area geometry on potential roof falls using the 2D numerical modelling program FLAC. In this respect, a half-prolate ellipsoid was considered as the low stress level or plasticity zone under yield tension which roof material fall. Since FLAC software does not show roof falls in prop-free front of the face, a series of two-dimensional numerical models are developed using UDEC software. The comparison of the results of two numerical models clearly indicates that volumes of roof fall obtained by means of these methods are in good agreement with each other.
Results from Dealing with Rock and Gas Outburst Prevention in The Czech Republic / Efekty Działań Mających Na Celu Zapobieganie Wybuchom Skał I Gazu, Podejmowanych W Republice Czeskiej
Authors: Hudeček Vlastimil , Zapletal Pavel , Stoniš Milan , Sojka Radislav 
Published: November 2013

Abstract
In the Czech Republic, the prevention of rock and gas outbursts is carried out in the course of driving mine workings in seams and in sandstone and conglomerate beds classified into a category with the highest degree of rock and gas outburst hazard. It is a case of active methods that aim at prevention of rock and gas outbursts by creating a protection zone in front of and in sides of mine workings being driven and passive methods that mitigate the effects of outbursts (Hudeček et al., 2009, 2010).
In this article, authors present recommendations and proposals for changes in rock and gas outburst prevention. These proposed changes should reflect in increased efficiency in coping with this anomalous geomechanical events.
Determination of the Friction Work of a Link Chain Interworking with a Sprocket Drum / Wyznaczenie Pracy Tarcia Łańcucha Ogniwowego We Współdziałaniu Z Bębnem Łańcuchowym
Authors: Sobota Piotr 
Published: November 2013

Abstract
The significant abrasive wear of sprocket drum teeth and seats bottoms is observed during the exploitation of longwall scraper conveyors. For this reason, it is important to determine friction work in sliding conditions of the horizontal link on the tooth seat bottom and on the tooth flank and friction work in the joint of links in the context of such nodes’ abrasive wear. The different construction variants of sprocket drums can be compared by determining friction work in the sliding positions of the horizontal link on the drum. The determination of the losses of the power transmitted is a requisite condition in such situation for determining the efficiency values of chain meshing. The friction work of the friction couple of a sprocket drum - link chain consists of friction work of the horizontal link in the places where it contacts with the seat bottom Ag and the tooth flank Af and friction work in the joints of a horizontal link in the contact place with vertical links: in the front joint Ap and the rear joint At. The article presents dependencies enabling to determine the value of such work for specific geometric relations between the chain and the drum and different friction conditions. The curves of relative friction work and the values of total friction work on the seat bottom, on the tooth flank and in a front and rear joint of links are presented for examples of friction conditions.
Analysis of Methods Used for Assessing Damage Risk of Buildings Under the Influence of Underground Exploitation in the Light of World’s Experience – Part 1 / Analiza Metod Oceny Zagrożenia Obiektów Budowlanych Eksploatacją Podziemną W Świetle Doświadczeń Światowych – Część 1
Authors: Malinowska Agnieszka 
Published: November 2013

Abstract
Methods used for evaluating damage risk of buildings threatened with continuous strains generated by underground exploitation have been addressed in this paper. The main emphasis was put on methods thanks to which the degree of damage of a large group of structural objects could be approximated. The investigations were focused on the origin of those methods, especially the assumed criteria. The final stage of theoretical study was a comparative analysis of presented methods, thanks to which the basic differences between assumptions to those methods as well as the main advantages and disadvantages could be enumerated. Then the damage risk of buildings was evaluated with selected methods. The obtained results were compared with actual data registered in those objects. This enabled the authors to practically evaluate the adaptability of those methods to the underground exploitation conditions in Poland. The first part of the paper is devoted to the presentation of methods and theoretical anaysis of their shortcomings and advantages, followed by the results of analyses performed on actual data.
Evaluation of Blasting Patterns Using Operational Research Models / Ocena Planów Prac Strzałowych W Oparciu O Metody Badań Operacyjnych
Authors: Monjezi Masoud , Farzaneh Farhad , Asadi Ahmad 
Published: November 2013

Abstract
Blasting is one of the most important operations, which has a great technical and economical effect on the mining projects. Criteria such as fragmentation (operation ultimate objective) and ground vibration, flyrock, airblast, etc. (operation side effects) should be considered in the assessment of blasting operation. A suitable pattern should be able to provide both reasonable (required) fragmentation and blasting side effects. In order to evaluate blasting performance, operational research models such as multi attribute decision making technique (MADM) can be applied. Technique for order preference by similarity to an ideal solution (TOPSIS), a branch of MADM, is a strong method for pattern ranking. The other quantitative method which is applied in the evaluation of systems’ efficiency is data envelopment analysis (DEA) model. In this paper, an attempt has been made to develop a new hybrid MADM model for selecting the most appropriate blasting pattern in Chadormalu iron mine, Iran. In this regard, DEA method was utilized to select the efficient blast patterns thereafter TOPSIS was used to recognize the most suitable pattern amongst the selected patterns by DEA method. It was concluded that the patterns J, G and B are the most appropriate patterns for blasting operations in the Chadormalu iron mine.
Measurement of Small Values of Hydrostatic Pressure with the Compensation of Atmospheric Pressure Influence / Pomiar Małych Wartości Ciśnienia Hydrostatycznego Z Kompensacją Wpływu Ciśnienia Atmosferycznego
Authors: Broda Krzysztof , Filipek Wiktor 
Published: November 2013

Abstract
Knowledge of pressure distribution (or differential pressure ) determines the fluid flow description through the porous medium. In the case of big Reynolds numbers it is not difficult, but for laminar flows (i.e. for Re numbers Bear, 1988; Duckworth, 1983; Troskolański, 1957) from the scope 0.01 to 3) this description is virtually impossible on the basis of the tools available on the market. The previous study (Broda & Filipek, 2012) focused on the difficulty of measurement in the case of small differences of pressure and suggested a new original method for the measurement. A new unit for the measurement was constructed consisting of two separate measurement containers. Then the measurements were conducted, which necessitated temperature stabilization of the device and compensation of the atmospheric pressure influence on the measurement process.
This paper presents the results of the continuation of research concerning the methods and equipment for the measurement of very small pressure differences. The paper includes also the experience gained from the new measurement unit, which was presented in figures 1-5 subsequently presenting the concept of measurement of small values of hydrodynamic pressure with compensation of atmospheric pressure influence fig. 1; illustration presenting the state corresponding to the case of the lack of flow through the tested item fig 2; state corresponding to the fluid flow through the tested item fig. 3; then the description of the measurement of pressure drop on the tested item fig. 4 and the measurement methodology (relations (1) - (20)). Picture of the measurement unit and its components - fig. 5.
Furthermore, the authors present an exemplary measurement series and focus on the method of measurement and data processing - tables 1-8 and figures 6-8.
Table 4 presents the comparison of the measurement unit used in the previous research (Broda & Filipek, 2012) and the new one - presented in the paper. It should be noted that the structure has been simplified and the measurement accuracy has increased.
Measurement of biofunctional muscle activity of the maxillofacial area in the treatment of mesial occlusion with myofunctional apparatus
Authors: Lykhota K.N. , Kochin A.V. , Petrychenko A.V. , Mocanu S.I. 
Published: November 2013

Abstract
The paper presents measurements of electromyographic (EMG) parameters in the study of 63 patients, aged 9-12 years during their treatment of dentoalveolar form mesial occlusion with myofunctional equipment. After treatment, the EMG figures closer to the norm.