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The continuous development of human society from a technical-economic point of view is closely related to the increase in energy consumption. However, this implies the rapid depletion of existing fossil fuels and an accelerated increase in global pollution. At the moment, to counteract these impediments, one of the most important sources that can be used for the purpose of energy production, without having a negative impact on the environment, is hydrogen. Due to the fact that, when mixed with air, hydrogen can generate potentially explosive atmospheres, it is necessary to adopt and apply protective measures aimed at ensuring an acceptable level of protection in accordance with current regulations. These measures materialize mainly through the use of appropriately protected technical equipment in locations where potentially explosive atmospheres generated by the presence of hydrogen are possible. Some of these equipment's are provided with non-metallic casings on which the type of protection of the respective equipment depends. That is why, in order to demonstrate the ability of the non-metallic materials that make up the equipment casings, to maintain the specific type of protection after exposure to extreme, positive and negative temperatures, it is of particular importance to determine the thermal endurance of the respective casings by performing laboratory tests. This paper highlights the importance of determining the thermal endurance in the case of equipment with non-metallic casings and non-metallic parts of the casings intended to be used in potentially explosive atmospheres generated by hydrogen, as well as the method and equipment required to perform laboratory tests for its determination. [ABSTRACT FROM AUTHOR]

‘Pyrotechnic article’ are products that contain explosive substances or an explosive mixture of substances designed to produce heat, sound, light, gas or smoke or a combination of such effects.Depending on the purpose for which they were made, pyrotechnic articles are used for entertainment purposes (fireworks), for the stage including film or television productions as well as for technical purposes.Due to the constituent substances, the pyrotechnic articles have a low or high risk level depending on the type and category of the pyrotechnic article, the quantities of explosive substances they contain, the visual and aural effects they produce during functioning etc.These specific characteristics of pyrotechnic articles, represent the criteria for "making available on the market" of these products, in the sense of being used by the general public or by people with specialized knowledge.For those who use them but those who are near pyrotechnic articles also during operation (persons, people with specialized knowledge, public) to be safe, these types of products must be subject to some evaluation / verification processes.The paper presents specific methods for testing fireworks, by which the conformity / non-conformity with the essential security requirements applicable can be highlighted, which leads to the possibility / impossibility of making available on the market these products.Also, are presented the results obtained in carrying out specific laboratory tests, concrete situations found during the tests and same factors that may influence the safe functioning of the pyrotechnic articles.Several factors that can influence the safe functioning of pyrotechnic articles are storage conditions related to temperature and humidity, transport conditions related to vibration. [ABSTRACT FROM AUTHOR]

The snow/sun shed is a proven mitigation technique effective in stopping progressive permafrost thawing beneath embankment side-slopes. However, safety concerns and highconstruction expenses have prevented the widespread use of snow/sun sheds for embankment protection. To find a better low-cost deployable system that still uses the same cooling principles than the snow/sun shed, a new mitigation technique was tested at Laval University. A series of half pipes were applied on a small-scale embankment slope in a cold room set at -20°C. The temperatures measured in the embankment slope at 0.22 m below the soil surface are: 1) -5.2°C lower compared to the reference embankment when the half-pipes extremities were left open to air circulation; 2) -4.6°C lower when the inlets of the half-pipes were sealed with mineral wool (to simulate snow clogging); 3) -4.2°C when both extremities were sealed with mineral wool. In terms of heat fluxes, the three configurations of half pipe cover tested were between 1.7 to 1.8 times more effective at extracting heat than the reference embankment. Finally, implementing this mitigation technique on the slopes of a road embankment has the potential to induce a significant cooling of soil temperatures. [ABSTRACT FROM AUTHOR]

Open pit reclamation is the final phase of mining activity to which every owner of the mining company is obliged. The selection of the target concept of the direction of decommissioning and reclamation of such excavation must be preceded by an analysis of the most optimal effects resulting from socio-economic and technical-environmental needs. The main research area on which research is being conducted is the sand open pit in the final phase of operation, whose excavations are simultaneously recultivated by their full backfilling with allochthone post-mining material (Carboniferous clastic compact rocks) from almost all hard coal mines in the Upper Silesian Coal Basin in Poland. Observations carried out on the research field selected by the authors indicate that due to the still dynamic situation resulting from the specificity of this object, the current approach with regard to the scope of laboratory and model tests is insufficient. Based on these conclusions, the authors proposed a modification and extension of the scope of laboratory tests supporting the stage of numerical modeling. A unified scheme of research activities verified in the laboratory scale was prepared, allowing for the selection of the underground water management method so that the environmental effects of mining exploitation and subsequent reclamation of the open pit would be as least onerous as possible over a long period of time. [ABSTRACT FROM AUTHOR]

The determination of bitumen dosages for asphalt mixtures using empirical or semiempirical methods (the specific surface method being the most well-known) no longer meets national or international technical standards. Most countries require the use of methods for determining the optimum binder content by laboratory tests grouped, usually, on several levels according to the Marshall or Superpave mix design. Romanian technical standards in this field are European and national standards, which unequivocally impose well established limits for each constituent and each characteristic of the prepared asphalt mixture, the mix design method approached being the Marshall one. These Romanian standards have been adopted in the last years and the results obtained in specialized laboratories contradict, in many cases, the values imposed by the current technical standards. The paper presents a series of laboratory tests performed to determine the optimum bitumen content for the production of an asphalt concrete for the wearing course. The tests highlight the fact that, regardless of the grading, it is difficult to achieve all the required physical and mechanical characteristics, starting from rangimg the bitumen content within the limits imposed by the Romanian technical standards. The mentioned laboratory tests are part of a broader research to be carried out in the next period of time and the authors wish to collaborate with other specialists for a possible revision of the Romanian standards requirements in this field. [ABSTRACT FROM AUTHOR]

Conveyor belts operated on belt conveyors are subjected to a variety of loads that lead to damage. Belts undergo wear in a process that depends on the type of conveyor, its length, the material transported and the working site [2, 3, 5, 8]. Laboratory evaluation of a conveyor belt's lifetime requires determining a number of its properties, such as tensile strength, longitudinal and transverse elongation strength, delamination strength, shear strength, flammability, and resistance to low temperatures, as well as rubber cover tensile strength, abrasion resistance, aging resistance, etc. The methods for measuring the above mentioned properties, as well as the required limit values for the properties, are standardized. However, a group of belt properties has not yet been standardized, although they have a fundamental importance for belt lifetime. Tests performed for many years in operating conditions show that the majority of belts undergo wear and are disassembled from the conveyor as a result of damage caused by punctures and cuts [4, 8, 9, 10]. Therefore, an assumption may be made that the resistance of conveyor belts to punctures and longitudinal cuts are among the most important criteria for the evaluation of their lifetime, which in turn remains a key factor affecting the costs related to the operation of belt conveyors. According to analyses performed in mining plants, the share of the costs of conveyor transportation is estimated to be between 8% and 30% of the production cost, depending on the type of a mine. These costs include both the cost of electricity and the costs related to the wear and replacement of belt conveyor elements, especially of conveyor belts. The aim of this paper is to present the results of research into conveyor belts, which may be implemented in mining industry to lower the costs of operating a conveyor transportation system [11, 12]. [ABSTRACT FROM AUTHOR]

A conveyor belt in regular operation is negatively influenced by a number of factors. This negative influence is the result of coming in direct contact with the transported material, which frequently causes serious damage and reduces belt lifetime. The scale and type of this damage depends on many factors, such as a belt's physical and mechanical properties and its design. The properties of the transported material and the design of the feed point are also of considerable importance [4]. When the damage is caused not only to the carrying cover, but also to the belt core, it becomes a threat to the operation of the belt conveyor. Therefore, research into safe operating conditions for conveyor belts remains of crucial importance. This paper presents the results of tests which allow defining the influence of conveyor belt design on the belt's wear and tear, in particular on punctures. Laboratory tests of conveyor belt puncture resistance were performed according to a method developed at Wroclaw University of Science and Technology [6, 10]. Belt puncture resistance was determined using a method based on calculating mean impact energy and critical energy. The tested belts had equal nominal tensile strength of 2000 kN/m, but were of different design and comprised cores made of different materials. [ABSTRACT FROM AUTHOR]

Twenty years after finishing the dam Čunovo on river Danube about 15 km beneath Bratislava were after regular controls gradually exclude from system some observation boreholes. There were realised new investigation boreholes. The main reason of these boreholes was verification of the soil characteristics in depth where the periodical changing of water in Danube and in reservoir had negative influence on the permeability characteristics. One of the most important factors of safety is filtration stability of granular soils. In boreholes was periodically measured the velocity of groundwater and from results analysed the safety of soils below the protective dam. Results after 2010 showed that the filtration stability of soils was decreased. Several theoretical criteria of filtration stability were applied for validation of experimental results. The paper will put the focus on field and laboratory analysing of the soil investigation. Comprehensive assessment of theoretical knowledge relating to the soil degradation by hydrodynamic influence of groundwater and results of field measurement was recommended preparing the construction of sealing cut-of-wall interferes in depth at minimum 20 m below the ground surface. [ABSTRACT FROM AUTHOR]

Loess and loess-like sediments cover almost 10 % of the area of Slovakia. A major problem in geotechnical practice encountered in loess deposits are structural collapses caused by loading and water content changes. Collapsible soils are unsaturated soils that undergo a large volume change upon saturation. Loess deposits represent a difficult ground conditions in civil engineering and they can often cause large differential settlements that reduce the serviceability of the structures. Determination of degree of collapsibility coefficient is important to prevent structural damage. Loess is a fine grained silty soil, windblown type of unconsolidated aggradation transported by wind. The collapsible soil is composed of silt and sand grains covered by clay/carbonate films, connected by clay/carbonate bridges and clay buttresses. The methods for collapsibility evaluating of loess in Slovakia and clasification of collapssible soils are disscussed in the paper. Conditions and criteria for soil collapse such as genesis, silt content, clay content, degree of saturation, liquid limit and bulk density are analysed in the paper. This work analyzes experimental results obtained in laboratory and field testining performed in loess sediments near the Trnava city in Slovakia. Evoluation of constrained modulus from field tests is discussed. [ABSTRACT FROM AUTHOR]

Controlling waste tires became a growing problem in the world because it represents a special solid waste that is difficult to manage. Many stockpiles of scrap tires are located in urban areas resulting in environmental problems and public health issues. Applying recycled waste tires to highway constructions is an alternative that can be used to reduce the problem. In this case, the rubber from waste tires is reduced to smaller pieces and introduced into asphalt in order to produce asphalt rubber. However, the asphalt rubber composition depends on some variables that must be studied and quantified in the laboratory. Asphalt rubber requires batching blending and reaction time associated with blending rubber and conventional asphalt to produce asphalt rubber. The ideal blending of these materials is dependent on the combination of the most important variables such as the amount of rubber, the reaction time and the temperature of reaction. This paper's goal is to optimize, in the laboratory, the asphalt rubber produced by continuous blend process. The rubber from waste tires was reduced by ambient grinding and the conventional asphalt used was the CAP- 50/70, currently applied in Brazilian mixes. In order to obtain the desired asphalt rubber, nine asphalt rubbers were produced, with different variables (amount of rubber, reaction time, and temperature reaction). The asphalt rubber properties were measured through these standard tests: (i) penetration; (ii) softening point; (iii) resilience; and (iv) apparent viscosity using a Brookfield viscometer. In addition, the microstructure of the asphalt rubbers was evaluated by Scanning Electron Microscopy (SEM). The results showed that the optimum asphalt rubber to produce asphalt mixtures is: 17% amount of rubber; 90 minutes of reaction time at 180°C (356°F). [ABSTRACT FROM AUTHOR]

This paper presents the outcome of experimental laboratory testing of geotechnical parameters of soils specimen with various lime content and their comparison (e. g. California Bearing Ratio, compaction characteristics). Stabilization of soils using admixtures and soil improvement by lime in geotechnical design is discussed. In order to illustrate clay improvements, three of the most frequently types of clays in Slovakia were used for experimental study and the content of lime varied from 0 to 4 %. Results of the laboratory investigation with the soil treated and the changes of mechanical properties due to lime addition as far as the results from the field lime treatment are analyzed in the paper. Some case studies on ground improvement by lime from Slovakia are presented. The correlations, tables and graphs based on the empirical relationship between the value of California Bearing Ratio and modulus of elasticity which are used in geotechnical practice are discussed in the paper. Significant differences were observed in determination of the derived values of elasticity modulus using empirical correlations and the values determined by laboratory testing. [ABSTRACT FROM AUTHOR]

Failure by internal erosion is produced by the transport of soil particles within a soil stratum, at the interface of soil strata, or at the interface between the soil and the structure. Increasing of flood risks due to global climatic changes in the last 20 years have a large negative influence on the stability of protective dykes or opening of deep excavation pits in Quarternary soils with high ground water level. Hydrostatic or hydrodynamic load of ground water on soil particles finally results in progressive erosion, leading to collapse of the soil structure. Research at the Department of Geotechnics was focused on problems connected with filtration stability of non-cohesive soils in Slovak region. The paper present the results of laboratory tests verified in field conditions. The results were also compared with other international research. [ABSTRACT FROM AUTHOR]

The object of this work was perfomed laboratory tests and their subsequent evaluation to determine the deformational properties materials of the dump. Samples, that were tested in the laboratory, come from coal mine Bílina in Northern Bohemia. It is necessary to established the properties of these materials of dump and especially during the increase heights for reliable analysis of the behavior of the dump bodies. The construction of the internal dumps is associated with increased risk of slope instabilities and deformations during the increase heights of these dumps. This paper presents the results of laboratory tests materials of the dumps. Were carried out basic tests, direct shear tests and oedometer tests. On the basis of laboratory tests can determine the basic parameters and strain parameters of the materials of the dumps characteristic for coal mine in Bílina. These deformational parameters then are used as input parameters in mathematical modeling of stability of the dumps with the use of advanced constitutive models. Materials forming the dumps in a coal mine in Bílina are usually clay and claystone. A characteristic feature of these clays is the total high porosity associated with collapse behavior. During the storage the materials of the dumps are also changing the strength parameters of these materials. [ABSTRACT FROM AUTHOR]

This article discusses a study which examined debris flow at Hsia-Hsinkai Tribe in Liugui, Taiwan, on August 8, 2009. The study used the techniques of in-situ investigation, close-range photogrammetry, laboratory tests, stereographic projection and slope stability analysis in the examination. It revealed an internal friction angle of the aggrading soil materials. It employed a stereographic projection method to analyze the outcrops found on site.

The objective of this study is to evaluate the effectiveness of chemical material for the stabilization of very soft dredge material. An experimental set up is designed and implemented to test mud samples in Yildiz Technical University Geotechnical Laboratory. A specially designed plexiglass test tanks are used to evaluate improvement process of the samples. The determination of the geotechnical parameters of Halic Mud in its natural state and as well as mixed with fly ash and cement admixtures. In order to investigate the effects of chemical admixtures to Halic Mud, fly ash and cement admixtures are added to very soft mud specimens at ranges 5% , 10% and 20% respectively. Atterberg limit tests, Seepage induced consolidation test, Vane shear test are performed to determine the effects of chemical admixtures. Specimens are cured for 7, 14, 28 and 35 days. In order to evaluate the improvement process at each curing period, tests are repeated. Based on results obtained it can be concluded that the very soft Halic Mud can be successfully stabilized by the combined action of cement and fly ash admixtures. [ABSTRACT FROM AUTHOR]