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Volume 67 (2020): Issue 4 (December 2020)

Volume 67 (2020): Issue 3 (September 2020)

Volume 67 (2020): Issue 2 (June 2020)

Volume 67 (2020): Issue 1 (March 2020)

Volume 66 (2019): Issue 4 (December 2019)

Volume 66 (2019): Issue 3 (December 2019)

Volume 66 (2019): Issue 2 (June 2019)

Volume 66 (2019): Issue 1 (March 2019)

Volume 65 (2018): Issue 4 (December 2018)

Volume 65 (2018): Issue 3 (September 2018)

Volume 65 (2018): Issue 2 (September 2018)

Volume 65 (2018): Issue 1 (March 2018)

Volume 64 (2017): Issue 4 (December 2017)

Volume 64 (2017): Issue 3 (September 2017)

Volume 64 (2017): Issue 2 (July 2017)

Volume 64 (2017): Issue 1 (March 2017)

Volume 63 (2016): Issue 4 (December 2016)

Volume 63 (2016): Issue 3 (September 2016)

Volume 63 (2016): Issue 2 (July 2016)

Volume 63 (2016): Issue 1 (May 2016)

Journal Details
Format
Journal
eISSN
1854-7400
First Published
30 Mar 2016
Publication timeframe
4 times per year
Languages
English

Search

Volume 64 (2017): Issue 4 (December 2017)

Journal Details
Format
Journal
eISSN
1854-7400
First Published
30 Mar 2016
Publication timeframe
4 times per year
Languages
English

Search

5 Articles

Original scientific paper

Open Access

Use of a Combination of Vertical and Horizontal Boreholes in Massive Blasting of Benches in the Surface Quarry Rodež

Published Online: 04 Apr 2018
Page range: 189 - 198

Abstract

Abstract

This article deals with the extraction of minerals (limestone/marl/flysch) in the quarry Rodež, which is located in western Slovenia. During the extraction of minerals in a quarry, drilling and blasting of benches are used. The focus of the article is on the analysis of the parameters related to drilling and blasting in surface excavations when using a combination of explosions and introducing horizontal wells along with vertical holes in the bench. On the basis of the analysis of basic parameters through a combination of drilling horizontal wells and charging those with the ammonal + Anfex explosive, analyses of effects of seismic disturbances on potentially affected buildings have also been conducted. The article is connected to and deals exclusively with the basic parameters of drilling and blasting, with the introduction of horizontal drilling and with the analysis of seismic measurements of threatened buildings in accordance with the German standard German Institute for Standardisation (DIN) 4150 during the use of a new method of blasting.

Keywords

  • quarry
  • blasting
  • seismic measurements
  • DIN 4150
Open Access

The effect of protective atmosphere on decarburisation of the heat-treated surface of steel

Published Online: 04 Apr 2018
Page range: 199 - 204

Abstract

Abstract

In heat-treating furnaces, many different types of protective atmospheres are used. This article researches the effect of protective atmospheres on the quality of the surface layer of bolts during the process of heating to reach the temperature of hardening. For this research, we produced specimens that were annealed in the furnace with two different types of protective atmosphere, i.e. in atmospheres of endothermic gas and nitrogen. After hardening and tempering, we measured the hardness of the specimens and investigated the microstructure. We measured the hardness profile from the surface to the inside of the product. We found that the hardness of the surface of the tested product was lower while using protective atmosphere of nitrogen due to the occurrence of ferrite. The depth of the decarburised layer in this atmosphere reached up to 70 mm, where predominantly there was a microstructure of ferrite on the surface, and then, with depth, an increasingly mixed microstructure of ferrite and martensite was found. The depth of the decarburised layer for sample treated in endothermic gas was minimal (i.e. 10 mm) on the surface.

Keywords

  • heat treatment
  • protective atmosphere
  • decarburisation
  • endothermic gas
  • nitrogen
  • microstructure
Open Access

Geotechnical Site Investigation Using S-waves with Implications for Ground Motion Analysis

Published Online: 04 Apr 2018
Page range: 205 - 219

Abstract

Abstract

Evaluation results of shear wave attenuation-based ground motion restricted by fracture orientation and rheology, from among those of an extended experimental study, are presented herein. The issues of competence of fractured bedrock dynamically disturbed multilaterally are assessed. Disturbance is primarily modelled by Sh and Sv stimulation, given fracture orientation, while subjected to direct fracture stress regime conditions varying in time. Hence, directionalities of polarisation and stress are taken into consideration simultaneously following simple site-specific non-erodetic approach. Comparison of spectral curves and spectral ratio curves of attenuation with respect to variations of direction and stress emphasise the amplification of the ‘seismic response’ in one direction compared to the other, i.e. vertical vs. horizontal, in terms of weighing possibilities of or predicting structural integrity against failure. The composite analyses of multiple spectral curves not only enable determination of the orientation of the fracture set/s in space but also allow inferring the nature of more amplified response perpendicular to the crack surface compared to that of a response parallel to the crack surface.

Keywords

  • site investigation
  • attenuation examination
  • ground motions
  • S-wave evaluation
  • seismic amplification
Open Access

Methodology for preliminary assessment of the radioactivity in natural waters

Published Online: 04 Apr 2018
Page range: 221 - 226

Abstract

Abstract

This article presents the results of a preliminary assessment of the radioactivity of natural waters and the isotope analysis of drinking water. It describes the methods for the radiochemical preparation of water samples, which include concentration of uranium isotopes from water samples, extraction from impeding radionuclides and preparation of electrically countable samples. The results of violation of radioactive equilibrium between the isotopes 234U/238U and the several factors affecting this process in water samples have been obtained. It is clear from the obtained result that 234U isotope concentration in groundwater is higher than that in surface water.

Keywords

  • natural water
  • isotope analysis
  • radiochemical preparation
  • concentration of uranium isotopes
  • extraction
  • countable sample
  • violation of radioactive equilibrium
  • isotope concentration
Open Access

Interpretation of high resolution airborne magnetic data (HRAMD) of Ilesha and its environs, Southwest Nigeria, using Euler deconvolution method

Published Online: 04 Apr 2018
Page range: 227 - 241

Abstract

Abstract

Interpretation of high resolution aeromagnetic data of Ilesha and its environs within the basement complex of the geological setting of Southwestern Nigeria was carried out in the study. The study area is delimited by geographic latitudes 7°30′–8°00′N and longitudes 4°30′–5°00′E. This investigation was carried out using Euler deconvolution on filtered digitised total magnetic data (Sheet Number 243) to delineate geological structures within the area under consideration. The digitised airborne magnetic data acquired in 2009 were obtained from the archives of the Nigeria Geological Survey Agency (NGSA). The airborne magnetic data were filtered, processed and enhanced; the resultant data were subjected to qualitative and quantitative magnetic interpretation, geometry and depth weighting analyses across the study area using Euler deconvolution filter control file in Oasis Montag software. Total magnetic intensity distribution in the field ranged from –77.7 to 139.7 nT. Total magnetic field intensities reveal high-magnitude magnetic intensity values (high-amplitude anomaly) and magnetic low intensities (low-amplitude magnetic anomaly) in the area under consideration. The study area is characterised with high intensity correlated with lithological variation in the basement. The sharp contrast is enhanced due to the sharp contrast in magnetic intensity between the magnetic susceptibilities of the crystalline and sedimentary rocks. The reduced-to-equator (RTE) map is characterised by high frequencies, short wavelengths, small size, weak intensity, sharp low amplitude and nearly irregular shaped anomalies, which may due to near-surface sources, such as shallow geologic units and cultural features. Euler deconvolution solution indicates a generally undulating basement, with a depth ranging from −500 to 1000 m. The Euler deconvolution results show that the basement relief is generally gentle and flat, lying within the basement terrain.

Keywords

  • aeromagnetic
  • anomaly
  • basement complex
  • data
  • Euler deconvolution
  • lithology
5 Articles

Original scientific paper

Open Access

Use of a Combination of Vertical and Horizontal Boreholes in Massive Blasting of Benches in the Surface Quarry Rodež

Published Online: 04 Apr 2018
Page range: 189 - 198

Abstract

Abstract

This article deals with the extraction of minerals (limestone/marl/flysch) in the quarry Rodež, which is located in western Slovenia. During the extraction of minerals in a quarry, drilling and blasting of benches are used. The focus of the article is on the analysis of the parameters related to drilling and blasting in surface excavations when using a combination of explosions and introducing horizontal wells along with vertical holes in the bench. On the basis of the analysis of basic parameters through a combination of drilling horizontal wells and charging those with the ammonal + Anfex explosive, analyses of effects of seismic disturbances on potentially affected buildings have also been conducted. The article is connected to and deals exclusively with the basic parameters of drilling and blasting, with the introduction of horizontal drilling and with the analysis of seismic measurements of threatened buildings in accordance with the German standard German Institute for Standardisation (DIN) 4150 during the use of a new method of blasting.

Keywords

  • quarry
  • blasting
  • seismic measurements
  • DIN 4150
Open Access

The effect of protective atmosphere on decarburisation of the heat-treated surface of steel

Published Online: 04 Apr 2018
Page range: 199 - 204

Abstract

Abstract

In heat-treating furnaces, many different types of protective atmospheres are used. This article researches the effect of protective atmospheres on the quality of the surface layer of bolts during the process of heating to reach the temperature of hardening. For this research, we produced specimens that were annealed in the furnace with two different types of protective atmosphere, i.e. in atmospheres of endothermic gas and nitrogen. After hardening and tempering, we measured the hardness of the specimens and investigated the microstructure. We measured the hardness profile from the surface to the inside of the product. We found that the hardness of the surface of the tested product was lower while using protective atmosphere of nitrogen due to the occurrence of ferrite. The depth of the decarburised layer in this atmosphere reached up to 70 mm, where predominantly there was a microstructure of ferrite on the surface, and then, with depth, an increasingly mixed microstructure of ferrite and martensite was found. The depth of the decarburised layer for sample treated in endothermic gas was minimal (i.e. 10 mm) on the surface.

Keywords

  • heat treatment
  • protective atmosphere
  • decarburisation
  • endothermic gas
  • nitrogen
  • microstructure
Open Access

Geotechnical Site Investigation Using S-waves with Implications for Ground Motion Analysis

Published Online: 04 Apr 2018
Page range: 205 - 219

Abstract

Abstract

Evaluation results of shear wave attenuation-based ground motion restricted by fracture orientation and rheology, from among those of an extended experimental study, are presented herein. The issues of competence of fractured bedrock dynamically disturbed multilaterally are assessed. Disturbance is primarily modelled by Sh and Sv stimulation, given fracture orientation, while subjected to direct fracture stress regime conditions varying in time. Hence, directionalities of polarisation and stress are taken into consideration simultaneously following simple site-specific non-erodetic approach. Comparison of spectral curves and spectral ratio curves of attenuation with respect to variations of direction and stress emphasise the amplification of the ‘seismic response’ in one direction compared to the other, i.e. vertical vs. horizontal, in terms of weighing possibilities of or predicting structural integrity against failure. The composite analyses of multiple spectral curves not only enable determination of the orientation of the fracture set/s in space but also allow inferring the nature of more amplified response perpendicular to the crack surface compared to that of a response parallel to the crack surface.

Keywords

  • site investigation
  • attenuation examination
  • ground motions
  • S-wave evaluation
  • seismic amplification
Open Access

Methodology for preliminary assessment of the radioactivity in natural waters

Published Online: 04 Apr 2018
Page range: 221 - 226

Abstract

Abstract

This article presents the results of a preliminary assessment of the radioactivity of natural waters and the isotope analysis of drinking water. It describes the methods for the radiochemical preparation of water samples, which include concentration of uranium isotopes from water samples, extraction from impeding radionuclides and preparation of electrically countable samples. The results of violation of radioactive equilibrium between the isotopes 234U/238U and the several factors affecting this process in water samples have been obtained. It is clear from the obtained result that 234U isotope concentration in groundwater is higher than that in surface water.

Keywords

  • natural water
  • isotope analysis
  • radiochemical preparation
  • concentration of uranium isotopes
  • extraction
  • countable sample
  • violation of radioactive equilibrium
  • isotope concentration
Open Access

Interpretation of high resolution airborne magnetic data (HRAMD) of Ilesha and its environs, Southwest Nigeria, using Euler deconvolution method

Published Online: 04 Apr 2018
Page range: 227 - 241

Abstract

Abstract

Interpretation of high resolution aeromagnetic data of Ilesha and its environs within the basement complex of the geological setting of Southwestern Nigeria was carried out in the study. The study area is delimited by geographic latitudes 7°30′–8°00′N and longitudes 4°30′–5°00′E. This investigation was carried out using Euler deconvolution on filtered digitised total magnetic data (Sheet Number 243) to delineate geological structures within the area under consideration. The digitised airborne magnetic data acquired in 2009 were obtained from the archives of the Nigeria Geological Survey Agency (NGSA). The airborne magnetic data were filtered, processed and enhanced; the resultant data were subjected to qualitative and quantitative magnetic interpretation, geometry and depth weighting analyses across the study area using Euler deconvolution filter control file in Oasis Montag software. Total magnetic intensity distribution in the field ranged from –77.7 to 139.7 nT. Total magnetic field intensities reveal high-magnitude magnetic intensity values (high-amplitude anomaly) and magnetic low intensities (low-amplitude magnetic anomaly) in the area under consideration. The study area is characterised with high intensity correlated with lithological variation in the basement. The sharp contrast is enhanced due to the sharp contrast in magnetic intensity between the magnetic susceptibilities of the crystalline and sedimentary rocks. The reduced-to-equator (RTE) map is characterised by high frequencies, short wavelengths, small size, weak intensity, sharp low amplitude and nearly irregular shaped anomalies, which may due to near-surface sources, such as shallow geologic units and cultural features. Euler deconvolution solution indicates a generally undulating basement, with a depth ranging from −500 to 1000 m. The Euler deconvolution results show that the basement relief is generally gentle and flat, lying within the basement terrain.

Keywords

  • aeromagnetic
  • anomaly
  • basement complex
  • data
  • Euler deconvolution
  • lithology

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