This paper discusses the results of gravimetric and magnetic investigations carried out on the Hans Glacier (Hansbreen) in the area of the Hornsund Fiord in Spitsbergen. These pilot investigations were performed in profiles running across to the extension of the glacier. Analysis of the magnetic measurements permits the supposition that in the base of the glacier there are amphibolites assigned to the Skålfjellet series, one of the oldest links of the metamorphic complex in Spitsbergen. Fig. 3 shows the behaviour of the amphibolites determined from the qualitative and quantitative properties of the anomalies ΔT. This paper also determined the thickness of the glacier in a cross-section 1.5 km distant from its front. From interpretation of the gravity anomaly, thickness varies between several and more than 100 m, taking the highest values in the central part of the glacier.
In this article results of diagnostic investigations of separately excited DC motor were presented. In diagnostics were applied a Fourier analysis method based on the fast Fourier transform (FFT) and a recognition method using Bayes classifier. In training process a set of the most important frequencies has been determined for which differences of corresponding signals in two states are the largest. Three categories of signals have been recognized in identification process: faultless state, state of the rotor broken one coil and state of the rotor shorted three coils
Evolution of many high technologies such as microelectronics, microsystem technology and nanotechnology involves design, application and testing of technical structures, whose size is being decreased continuously. Scanning probe microscopes (SPM) are therefore increasingly used as diagnostic and measurement instruments. Consequently the demand for standardized calibration routines for this kind of equipment rises. Up to now, there has been no in generally accepted guideline on how to perform SPM calibration procedure. In this article we discuss calibration scheme and focus on several critical aspects of SPM characterization e.g. the determination of the static and dynamic physical properties of the cantilever, the influence factors which need to be considered when plotting a scheme for the calibration of the force and displacement sensitivity.
Buckling and postbuckling response of thin-walled composite plates investigated experimentally and determinated analytically and numerically is compared. Real dimension specimens of composite plates weakened by cut-out subjected to uniform compression in laboratory buckling tests have been modelled in the finite element method and examined analytically based on P-w2 and P-w3 methods. All results were obtained during the experimental investigations and the numerical FEM analysis of a thin-walled composite plate made of a carbon-epoxy laminate with a symmetrical eight-layer arrangement of [90/-45/45/0]s. The instrument used for this purpose was a numerical ABAQUS® program.
The stability of gateroads is one of the key factors for the mining process of hard coal by a longwall system. Wrong designed and applied the gateroad support at the stage of drilling, may adversely affect the functionality of the gateroad and the safety of the crew throughout its existence.
The article presents the results of the underground tests and observations such as: convergence of the gateroad, stratification and the fractured zone range in the roof rocks, carried out in four longwall gateroads at the stage of their drilling.
The obtained test results were the basis for the assessment of the possibility of using a convergence control method in the design of the gateroad support. The method is based on three interdependent relationships, such as: Ground Reaction Curve (GRC), Longitudinal Displacement Profile (LDP), and a Support Characteristic Curve (SCC). All calculations were performed using numerical modeling in the Phase2 program, based on the finite element method (FEM).
Measurements of the hardening process of the selected self-setting sands are presented in the hereby paper. Moulding sands were prepared
on the matrix of „Szczakowa” sand of the Sibelco Company. Two resins: phenol-formaldehyde-furfuryl (FF/AF) and urea-formaldehydefurfuryl
(MF/AF) were used for making moulding sands. – Methylbenzene-sulphonic acid was applied as a hardener for the moulding sand
on FF/AF resin, while paratoluene-sulphonic acid for the moulding sand on MF/AF resin. Both hardeners were used in two concentrations:
low – the so-called ‘slow’ hardener and high - ‘fast’ hardener. During investigations, the courses of the hardening process were
determined, more accurately changes of the velocity of the ultrasound wave passage through the moulding sand cL = f(t) and changes of
the moulding sand hardening degree versus time, Sx = f(t). In addition, the kinetics of the hardening process was determined.
Measurements were performed on the research stand for ultrasound investigations.
The article presents research results of physico-chemical and environmental issues for the dust generated during dedusting of the
installation for the processing and preparation of moulding sand with bentonite. Particular attention was paid to the content of heavy
metals and emission of gases from the BTEX group, which is one of the determinants of the moulding sands harmfulness for the
environment. The analysis of heavy metals in the test samples indicate that there is an increase of the content of all metals in the dust
compared to the initial mixture of bentonite. The most significant (almost double) increase observed for zinc is probably related to the
adsorption of this element on the dust surface by contact with the liquid metal. The study showed, that dust contained more than 20% of
the amount of montmorillonite and had a loss on ignition at a similar level. The addition of 1% of dust to the used moulding sand results in
almost 30% increase in the total volume of gases generated in casting processes and nearly 30% increase of the benzene emission.
Measurements of the hardening process course of the selected self-hardening moulding sands with the reclaimed material additions to the matrix, are presented in the hereby paper. Moulding sands were produced on the „Szczakowa” sand (of the Sibelco Company) as the matrix of the main fraction FG 0,40/0,32/0,20, while the reclaim was added to it in amounts of 20, 50 and 70%. Regeneration was performed with a horizontal mechanical regenerator capacity of 10 t/h. In addition, two moulding sands, one on the fresh sand matrix another on the reclaimed matrix, were prepared for comparison. Highly-fluid urea-furfuryl resin was used as a binder, while paratoluensulphonic acid as a hardener. During investigations the hardening process course was determined, it means the wave velocity change in time: cL = f(t). The hardening process kinetics was also assessed (dClx/dt = f(t)). Investigations were carried out on the research stand for ultrasound tests. In addition strength tests were performed.
The effects of filling the core box cavity and sand compaction in processes of core production by blowing methods (blowing, shooting)
depend on several main factors. The most important are: geometrical parameters of cavity and complexity of its shape, number,
distribution and shape of blowing holes feeding sands as well as the venting of a technological cavity. Values of individual parameters are
selected according to various criteria, but mostly they should be adjusted to properties of the applied core sand.
Various methods developed by several researchers, including the authors own attempts, allow to assess core sands properties on the basis
of special technological tests projecting the process into a laboratory scale. The developed criteria defining a degree or a filling ability
factor provide a better possibility of assessing the core sand behavior during flowing and core box filling, which indicate the value and
structure of the obtained compacting decisive – after hardening – for strength and permeability. The mentioned above aspects are analyzed
– on the basis of authors’ own examinations - in the hereby paper.
Shape memory alloys are characterised by interesting properties, i.e. shape memory effect and pseudoelasticity, which enable their increasing application. Thermomechanical aspects of martensitic and reverse transformations in TiNi shape memory alloy subjected to tension tests were investigated. The stress-strain characteristics obtained during the tests were completed by the temperature characteristics. The temperature changes were calculated on the basis of thermograms determined by an infrared camera. Taking advantages from the infrared technique, the temperature distributions on the specimen’s surface were found. Heterogeneous temperature distributions, related to the nucleation and development of the new martensite phase, were registered and analysed. A significant temperature increase, up to 30 K, was registered during the martensitic transformation. The similar effects of the heterogeneous temperature distribution were observed during unloading, while the reverse transformation, martensite into austenite took place, accompanied by significant temperature decrease.
The paper presents an estimation of liquefaction susceptibility of some soils from the coast of the Marmara Sea, which was heavily
striken by the Kocaeli earthquake in 1999. Firstly, the results of field investigations are summarized. Then, the results of laboratory investigations of physical and mechanical properties of the soils collated from the sites investigated are presented. The mechanical properties relate to the compaction/liquefaction model of saturated soils. This model is briefly outlined, then respective experimental procedures dealing with its calibration described, and values of material parameters listed. Liquefaction potential of investigated soils is analysed using standard procedures, based on the grain size distribution curves and SPTs. Finally, the simulation of pore-pressure generation and onset of liquefaction of Turkish soils is carried out, using the compaction/liquefaction model. Discussion of some standard empirical procedures of estimation of liquefaction potential of saturated soils, conducted from the analytical point of view, is also presented.
The paper deals with experimental investigations of a set of metal "2-delta" gaskets of different depth. The gaskets were examined under assembly conditions, i.e. placed in their seats and loaded with the compressive assembly force with no operating pressure applied to the closure. The electric resistance wire strain gauges were used to measure the circumferential and axial strains at the inner cylindrical surface of the gaskets. The plastic deformations of the contact surface of the seats were measured after disassembly of the closures. The material tests were carried out to determine real mechanical properties of materials applied for the gaskets and the seats. The results of experiment were compared with the analytical approach. The plastic deformations were taken into account in the analytical solution of the contact region between the gasket and the seats. The results of experiment and analytical approach were verified by FEM calculations, which take into account linear hardening of the material, friction and contact effects.
This article presents a case study of a large wedge failure. It took place during excavation of the last bench of storage cavern with an approximate dimension of 80 m long having a depth of 8 m. The adopted intervention followed a structured approach, which included immediate rock support, geotechnical and geological investigations in the failure zone and design modifications. Back analyses of the failure zone were also carried out to assess design parameters with observed geological conditions. Re assessment in the failure zone was carried out using modified design parameters, which included shorter benches, rock support installation schemes such as longer rock bolts, reinforced ribs of shotcrete and reduced construction advances. Geotechnical monitoring in and around failure zone were carried out for recording any alarming movements in the rock mass. Initially, geotechnical monitoring was carried out in the recently excavated zone of the cavern on a daily basis. Based on continuous monitoring data for at least one week, the frequency of subsequent monitoring can be decided. In most cases the deformation of rock mass was considerably less than the alarming values which were calculated based on detailed design for different rock classes. The paper discusses the failure, investigation, cause, assessment and remedial measures to complete the construction of cavern.
At the end of August 2012 the Polish Parliament enacted the Act on State Marine Accident Investigation Commission, which regulates its organization and operation. The Act transposed, within its regulation, Directive 2009/18/EC of the European Parliament and of the Council of 23 April 2009 establishing the fundamental principles governing the investigation of accidents in the maritime transport sector and is based on the Code of the International Standards and Recommended Practices for a Safety Investigation into a Marine Casualty or Marine Incident (Casualty Investigation Code), issued by the International Maritime Organization (IMO) together with amendments to the SOLAS Convention. The purpose of the Directive, as well as the Casualty Investigation Code, is to improve maritime safety and the prevention of pollution by ships by facilitating the expeditious holding of safety investigations and proper analysis of marine casualties and incidents in order to determine their causes. The EU Parliament obliged, through the Directive, the EU Member States to ensure that the safety investigations are conducted under the responsibility of an impartial permanent investigative body, endowed with the necessary powers, and by suitably qualified investigators, competent in matters relating to marine casualties and incidents. This impartial permanent investigative body had been named in Poland: Państwowa Komisja Badania Wypadków Morskich [the State Marine accident Investigation Commission] and began its operation in May 2013 upon the appointment, by the Minister of Transport, Construction and Maritime Economy, of the third one of five statutory members of the Commission. Since the beginning of its activity the Commission has initiated 77 safety investigations, prepared and adopted 272 resolutions, published 53 safety reports and issued more than 30 safety recommendations. The establishment and activity of the Commission leads to greater awareness of casualty causation and has a positive impact on the level of maritime safety.
Field investigations concerning screw piles and columns have been carried out for the “Bearing capacity and work in the soil of screw piles” research project, financed by the Polish Ministry of Science and Higher Education – project No N N506 369234. The tests of three instrumented screw piles were conducted together with CPTU tests and measurements of pile installation parameters (especially torque). The objectives of field investigations and the entire research project include discovering how screw piles work in the soil, locating and describing the correlations between CPTU results and rotation resistance during pile auger installation and next establishing correlations between CPTU results, rotation resistance and the bearing capacity of this kind of piles. The paper describes the investigation procedure and the basic results of tests carried out in the first of a series of sites.
The paper deals with experimental investigations of a set of metal wave-ring gaskets of different thickness and different assembly interference. The gaskets were examined under assembly conditions, i.e. pressed in their seats with no operating pressure applied. The electric resistance wire strain gauges were used to measure the circumferential and axial strains at the inner surface of the gaskets. The traces of contact at the working surface of the gaskets were measured after disassembly the gaskets from their seats. The material tests were carried out to determine the real mechanical properties of materials applied for the gaskets and the seats. The results of experiment were verified by FEM calculations and compared with the analytical approach based on the simplified shell model proposed for the gasket.