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Sample records for h-13 die steel

  1. Mechanism of improvement on strength and toughness of H13 die steel by nitrogen

    International Nuclear Information System (INIS)

    Li, Jing-Yuan; Chen, Yu-Lai; Huo, Jian-Hua

    2015-01-01

    The mechanism of nitrogen addition to AISI H13 die steel is proposed and supported using thermodynamic calculations in addition to observed changes in precipitate, microstructure, crystal structure, and macroproperties. The results indicate that the average impact toughness ak of the novel nitrogen H13 steel is maximally 17.6 J cm −2 and minimally 13.4 J cm −2 . These values result in die steel that reaches premium grade and approximate the superior grade as specified in NADCA#207-2003, additionally the hardness is improved 3–5HRC. Experimental findings indicate that the residual V(C,N) particles undissolved during nitrogen H13 steel austenitizing by quenching helps to suppress growth of original austenitic crystal grains, this in turn results in finer martensitic structures after quenching. In the subsequent tempering process all N atoms are dissolved in the solid state matrix a result of C atoms displacing N atoms in V(C,N). Solid dissolution of N atoms produces a distorted lattice of Fe matrix which results in an increase in the hardness of the steel. Additionally this displacement reaction is important for slow growth of secondary particles in nitrogen H13 steel during the tempering process which helps to increase impact toughness compared to its nitrogen-free counterpart given the same condition of heat-treatment

  2. Laser Surface Modification of H13 Die Steel using Different Laser Spot Sizes

    Science.gov (United States)

    Aqida, S. N.; Naher, S.; Brabazon, D.

    2011-05-01

    This paper presents a laser surface modification process of AISI H13 tool steel using three sizes of laser spot with an aim to achieve reduced grain size and surface roughness. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 tool steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, overlap percentage and pulse repetition frequency (PRF). Metallographic study and image analysis were done to measure the grain size and the modified surface roughness was measured using two-dimensional surface profilometer. From metallographic study, the smallest grain sizes measured by laser modified surface were between 0.51 μm and 2.54 μm. The minimum surface roughness, Ra, recorded was 3.0 μm. This surface roughness of the modified die steel is similar to the surface quality of cast products. The grain size correlation with hardness followed the findings correlate with Hall-Petch relationship. The potential found for increase in surface hardness represents an important method to sustain tooling life.

  3. Precipitation Behavior of Carbides in H13 Hot Work Die Steel and Its Strengthening during Tempering

    Directory of Open Access Journals (Sweden)

    Angang Ning

    2017-02-01

    Full Text Available The properties of carbides, such as morphology, size, and type, in H13 hot work die steel were studied with optical microscopy, transmission electron microscopy, electron diffraction, and energy dispersive X-ray analysis; their size distribution and quantity after tempering, at different positions within the ingot, were analyzed using Image-Pro Plus software. Thermodynamic calculations were also performed for these carbides. The microstructures near the ingot surface were homogeneous and had slender martensite laths. Two kinds of carbide precipitates have been detected in H13: (1 MC and M6C, generally smaller than 200 nm; and (2 M23C6, usually larger than 200 nm. MC and M6C play the key role in precipitation hardening. These are the most frequent carbides precipitating at the halfway point from the center of the ingot, and the least frequent at the surface. From the center of the ingot to its surface, the size and volume fraction of the carbides decrease, and the toughness improves, while the contribution of the carbides to the yield strength increases.

  4. Improved Life of Die Casting Dies of H13 Steel by Attaining Improved Mechanical Properties and Distortion Control During Heat Treatment

    Energy Technology Data Exchange (ETDEWEB)

    J. F. Wallace; D. Schwam

    1998-10-01

    The ultimate goal of this project is to increase die casting die life by using fast enough quenching rates to obtain good toughness and fatigue resistance in premium grade H-13 steel dies. The main tasks of the project were to compile a database on physical and mechanical properties of H-13; conduct gas quenching experiments to determine cooling rates of dies in difference vacuum furnaces; measure the as-quenched distortion of dies and the residual stresses; generate finite element analysis models to predict cooling rates, distortion, and residual stress of gas quenched dies; and establish rules and create PC-based expert system for prediction of cooling rates, distortion, and residual stress in vacuum/gas quenched H-13 dies. Cooling curves during gas quenching of H-13 blocks and die shapes have been measured under a variety of gas pressure. Dimensional changes caused by the gas quenching processes have been determined by accurate mapping of all surfaces with coordinate measuring machines before and after the quench. Residual stresses were determined by the ASTM E837 hole-drilling strain gage method. To facilitate the computer modeling work, a comprehensive database of H-13 mechanical and physical properties has been compiled. Finite element analysis of the heat treated shapes has been conducted using the TRAST/ABAQUS codes. There is a good fit between the predicted and measured distortion contours. However, the magnitude of the predicted distortion and residual stresses does not match well the measured values. Further fine tuning of the model is required before it can be used to predict distortion and residual stress in a quantitative manner. This last step is a prerequisite to generating rules for a reliable expert system.

  5. Improved life of die casting dies of H13 steel by attaining improved mechanical properties and distortion control during heat treatment. Year 1 report, October 1994--September 1995

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, J.F.; Schwam, D. [Case Western Reserve Univ., Cleveland, OH (United States)

    1995-03-01

    Optimum heat treatment of dies (quenching) is critical in ensuring satisfactory service performance: rapid cooling rates increase the thermal fatigue/heat checking resistance of the steel, although very fast cooling rates can also lead to distortion and lower fracture toughness, increasing the danger of catastrophic fracture. Goal of this project is to increase die life by using fast enough quenching rates (> 30 F/min ave cooling rate from 1750 to 550 F, 1/2 in. below working surfaces) to obtain good toughness and fatigue resistance in Premium grade H-13 steel dies. An iterative approach of computer modeling validated by experiment was taken. Cooling curves during gas quenching of H-13 blocks and die shapes were measured under 2, 5, and 7.5 bar N2 and 4 bar Ar. Resulting dimensional changes and residual stresses were determined. To facilitate the computer modeling work, a database of H-13 mechanical and physical properties was compiled. Finite element analysis of the heat treated shapes was conducted. Good fit of modeled vs measured quenched rates was demonstrated for simple die shapes. The models predict well the phase transformation products from the quench. There is good fit between predicted and measured distortion contours; however magnitude of predicted distortion and residual stresses does not match well the measured values. Further fine tuning of the model is required.

  6. Effects of heat treatment on mechanical properties of h13 steel

    Science.gov (United States)

    Guanghua, Yan; Xinmin, Huang; Yanqing, Wang; Xingguo, Qin; Ming, Yang; Zuoming, Chu; Kang, Jin

    2010-12-01

    Heat treatment on the mechanical properties of H13 hot working die steel for die casting is discussed. The H13 steel for die casting was treated by different temperatures of vacuum quenching, tempering, and secondary tempering to investigate its mechanical properties. Strength, plasticity, hardness, and impact toughness of the H13 hot working die steel for die casting were measured. Microstructure, grain size, and carbide particle size after heat treatment have a great impact on the mechanical properties of H13 hot working die steel for die casting. The microstructure of the H13 was analyzed by scanning electron microscopy (SEM) and by a metallographic microscope. It is found that H13 exhibits excellent mechanical properties after vacuum quenching at 1050°C and twice tempering at 600°C.

  7. Thermally-Induced Crack Evaluation in H13 Tool Steel

    Directory of Open Access Journals (Sweden)

    Hassan Abdulrssoul Abdulhadi

    2017-11-01

    Full Text Available This study reported the effect of thermal wear on cylindrical tool steel (AISI H13 under aluminum die-casting conditions. The AISIH13 steels were immersed in the molten aluminum alloy at 700 °C before water-quenching at room temperature. The process involved an alternating heating and cooling of each sample for a period of 24 s. The design of the immersion test apparatus stylistically simulated aluminum alloy dies casting conditions. The testing phase was performed at 1850, 3000, and 5000 cycles. The samples were subjected to visual inspection after each phase of testing, before being examined for metallographic studies, surface crack measurement, and hardness characteristics. Furthermore, the samples were segmented and examined under optical and Scanning Electron Microscopy (SEM. The areas around the crack zones were additionally examined under Energy Dispersive X-ray Spectroscopy (EDXS. The crack’s maximum length and Vickers hardness profiles were obtained; and from the metallographic study, an increase in the number of cycles during the testing phase resulted in an increase in the surface crack formation; suggesting an increase in the thermal stress at higher cycle numbers. The crack length of Region I (spherically shaped was about 47 to 127 µm, with a high oxygen content that was analyzed within 140 µm from the surface of the sample. At 700 °C, there is a formation of aluminum oxides, which was in contact with the surface of the H13 sample. These stresses propagate the thermal wear crack length into the tool material of spherically shaped Region I and cylindrically shape Region II, while hardness parameters presented a different observation. The crack length of Region I was about 32% higher than the crack length of Region II.

  8. Influence of cooling rate on phase formation in spray-formed H13 tool steel

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, K.M. [Industrial Technology Department, Idaho National Laboratory, Idaho Falls, ID 83415-2050 (United States)], E-mail: kevin.mchugh@inl.gov; Lin, Y.; Zhou, Y.; Lavernia, E.J. [Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616 (United States)

    2008-03-25

    Spray forming is an effective way to process many tool steels into near-net-shape molds, dies, and related tooling. The general approach involves depositing atomized droplets onto a refractory pattern in order to image the pattern's features. The pattern is removed and the die insert is mounted in a standard mold base or holding block. This approach results in significant cost and lead-time savings compared to conventional machining. Spray-formed dies perform well in many industrial forming operations, oftentimes exhibiting extended die life compared to conventional dies of the same material and design. Care must be exercised when spray forming tool steel dies to minimize porosity and control the nature and distribution of phases and residual stresses. Selection of post-deposition heat treatment is important to tailor the die's properties (hardness, strength, impact energy, etc.) for a particular application. This paper examines how the cooling rate during spray processing and heat treatment of H13 tool steel influences phase formation. Porosity and hardness were evaluated over a range of deposit cooling rates and residual stresses were evaluated for a die in the as-deposited condition. Finally, the performance of spray-formed dies during production runs in forging, extrusion, and die casting is described.

  9. Influence of cooling rate on phase formation in spray-formed H13 tool steel

    International Nuclear Information System (INIS)

    McHugh, K.M.; Lin, Y.; Zhou, Y.; Lavernia, E.J.

    2008-01-01

    Spray forming is an effective way to process many tool steels into near-net-shape molds, dies, and related tooling. The general approach involves depositing atomized droplets onto a refractory pattern in order to image the pattern's features. The pattern is removed and the die insert is mounted in a standard mold base or holding block. This approach results in significant cost and lead-time savings compared to conventional machining. Spray-formed dies perform well in many industrial forming operations, oftentimes exhibiting extended die life compared to conventional dies of the same material and design. Care must be exercised when spray forming tool steel dies to minimize porosity and control the nature and distribution of phases and residual stresses. Selection of post-deposition heat treatment is important to tailor the die's properties (hardness, strength, impact energy, etc.) for a particular application. This paper examines how the cooling rate during spray processing and heat treatment of H13 tool steel influences phase formation. Porosity and hardness were evaluated over a range of deposit cooling rates and residual stresses were evaluated for a die in the as-deposited condition. Finally, the performance of spray-formed dies during production runs in forging, extrusion, and die casting is described

  10. Atomic diffusion in laser surface modified AISI H13 steel

    Science.gov (United States)

    Aqida, S. N.; Brabazon, D.; Naher, S.

    2013-07-01

    This paper presents a laser surface modification process of AISI H13 steel using 0.09 and 0.4 mm of laser spot sizes with an aim to increase surface hardness and investigate elements diffusion in laser modified surface. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, pulse repetition frequency (PRF), and overlap percentage. The hardness properties were tested at 981 mN force. Metallographic study and energy dispersive X-ray spectroscopy (EDXS) were performed to observe presence of elements and their distribution in the sample surface. Maximum hardness achieved in the modified surface was 1017 HV0.1. Change of elements composition in the modified layer region was detected in the laser modified samples. Diffusion possibly occurred for C, Cr, Cu, Ni, and S elements. The potential found for increase in surface hardness represents an important method to sustain tooling life. The EDXS findings signify understanding of processing parameters effect on the modified surface composition.

  11. Modeling the Spray Forming of H13 Steel Tooling

    Science.gov (United States)

    Lin, Yaojun; McHugh, Kevin M.; Zhou, Yizhang; Lavernia, Enrique J.

    2007-07-01

    On the basis of a numerical model, the temperature and liquid fraction of spray-formed H13 tool steel are calculated as a function of time. Results show that a preheated substrate at the appropriate temperature can lead to very low porosity by increasing the liquid fraction in the deposited steel. The calculated cooling rate can lead to a microstructure consisting of martensite, lower bainite, retained austenite, and proeutectoid carbides in as-spray-formed material. In the temperature range between the solidus and liquidus temperatures, the calculated temperature of the spray-formed material increases with increasing substrate preheat temperature, resulting in a very low porosity by increasing the liquid fraction of the deposited steel. In the temperature region where austenite decomposition occurs, the substrate preheat temperature has a negligible influence on the cooling rate of the spray-formed material. On the basis of the calculated results, it is possible to generate sufficient liquid fraction during spray forming by using a high growth rate of the deposit without preheating the substrate, and the growth rate of the deposit has almost no influence on the cooling rate in the temperature region of austenite decomposition.

  12. The effect of deep cryogenic treatments on the mechanical properties of an AISI H13 steel

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, Marcos, E-mail: marcosperezrd@gmail.com; Belzunce, Francisco Javier

    2015-01-29

    Cryogenic treatments are considered a good way to reduce the retained austenite content and improve the performance of tool steels. Four different heat treatments, two of which included a deep cryogenic stage, were applied in this study to an H13 tool steel, subsequently determining its mechanical properties by means of tensile, hardness and fracture toughness tests. Furthermore, scanning electron microscopy and X-ray diffraction analysis were performed to gain an insight into the microstructural evolution of these heat treatments during all the stages. It was concluded that the application of a deep cryogenic treatment to H13 steel induces higher thermal stresses and structural defects, producing a dispersed network of fine carbides after the subsequent tempering stages, which were responsible for a significant improvement in the fracture toughness of this steel without modifying other mechanical properties. Although the application of a deep cryogenic treatment reduces the retained austenite content, there is a minimum innate content which cannot be transformed by heat treatment. Nevertheless, this austenite is hence believed to be stable enough and should not transform during the normal service life of forging dies.

  13. The effect of deep cryogenic treatments on the mechanical properties of an AISI H13 steel

    International Nuclear Information System (INIS)

    Pérez, Marcos; Belzunce, Francisco Javier

    2015-01-01

    Cryogenic treatments are considered a good way to reduce the retained austenite content and improve the performance of tool steels. Four different heat treatments, two of which included a deep cryogenic stage, were applied in this study to an H13 tool steel, subsequently determining its mechanical properties by means of tensile, hardness and fracture toughness tests. Furthermore, scanning electron microscopy and X-ray diffraction analysis were performed to gain an insight into the microstructural evolution of these heat treatments during all the stages. It was concluded that the application of a deep cryogenic treatment to H13 steel induces higher thermal stresses and structural defects, producing a dispersed network of fine carbides after the subsequent tempering stages, which were responsible for a significant improvement in the fracture toughness of this steel without modifying other mechanical properties. Although the application of a deep cryogenic treatment reduces the retained austenite content, there is a minimum innate content which cannot be transformed by heat treatment. Nevertheless, this austenite is hence believed to be stable enough and should not transform during the normal service life of forging dies

  14. CHARACTERIZATION OF NEW TOOL STEEL FOR ALUMINUM EXTRUSION DIES

    OpenAIRE

    José Britti Bacalhau; Fernanda Moreno Rodrigues; Rafael Agnelli Mesquita

    2014-01-01

    Aluminum extrusion dies are an important segment of application on industrial tools steels, which are manufactured in steels based on AISI H13 steel. The main properties of steels applied to extrusion dies are: wear resistance, impact resistance and tempering resistance. The present work discusses the characteristics of a newly developed hot work steel to be used on aluminum extrusion dies. The effects of Cr and Mo contents with respect to tempering resistance and the Al addition ...

  15. Laser Cladding of CPM Tool Steels on Hardened H13 Hot-Work Steel for Low-Cost High-Performance Automotive Tooling

    Science.gov (United States)

    Chen, J.; Xue, L.

    2012-06-01

    This paper summarizes our research on laser cladding of high-vanadium CPM® tool steels (3V, 9V, and 15V) onto the surfaces of low-cost hardened H13 hot-work tool steel to substantially enhance resistance against abrasive wear. The results provide great potential for fabricating high-performance automotive tooling (including molds and dies) at affordable cost. The microstructure and hardness development of the laser-clad tool steels so obtained are presented as well.

  16. Effects of Rare Earth on the Microstructure and Impact Toughness of H13 Steel

    OpenAIRE

    Gao, Jinzhu; Fu, Paixian; Liu, Hongwei; Li, Dianzhong

    2015-01-01

    Studies of H13 steel suggest that under appropriate conditions, additions of rare-earth metals (REM) can significantly enhance mechanical properties, such as impact toughness. This improvement is apparently due to the formation of finer and more dispersive RE inclusions and grain refinement after REM additions. In this present work, the microstructure evolution and mechanical properties of H13 steel with rare earth additions (0, 0.015, 0.025 and 0.1 wt.%) were investigated. The grain size, ...

  17. Evaluation of the mechanical properties of Niobium modified cast AISI H 13 hot work tool steel

    International Nuclear Information System (INIS)

    Noorian, A.; Kheirandish, Sh.; Saghafian, H.

    2010-01-01

    In this research, the effects of partially replacing of vanadium and molybdenum with niobium on the mechanical properties of AISIH 13 hot-work tool steel have been studied. Cast samples made of the modified new steel were homogenized and austenitized at different conditions, followed by tempering at the specified temperature ranges. Hardness, red hardness, three point bending test and Charpy impact test were carried out to evaluate the mechanical properties together with characterizing the microstructure of the modified steel using scanning electron microscope. The results show that niobium addition modifies the cast structure of Nb-alloyed steel, and increases its maximum hardness. It was found that bending strength; bending strain, impact strength, and red hardness of the modified cast steel are also higher than those of the cast H13 steel, and lower than those of the wrought H13 steel.

  18. Effects of advanced laser processing on the microstructure and residual stresses of H13 tool steel

    NARCIS (Netherlands)

    Trojan, Karel; Ocelík, Václav; Ganev, Nikolaj; Němeček, Stanislav; Čapek, Jiří

    2017-01-01

    The aim of this paper is to describe the effects of laser processing on the microstructure and residual stresses of laser cladded H13 tool steel on the classical construct steel S355 substrate. This research paper concludes that in this case of laser cladding, phase transformation and not shrinkage

  19. Partial substitution of vanadium by niobium in AISI H13 steel

    International Nuclear Information System (INIS)

    Itman Filho, A.; Balancin, O.

    1987-01-01

    The aim of this work was to study the tempering resistence in conditions of use of the AISI H13 steel, after partial substitution of vanadium by niobium. Four alloys of this steel were elaborated and in three of them the niobim was added in the contents of 0,2; 0,5 and 1,0%. Metallographic techniques were performed to compare qualitatively the niobium effect in several processing and thermal analisys of the steels. Grain size measurements were made after austenitization of the steels, hardness measurements in prepared samples were made after quenching and tempering, tensile testing at elevated temperature was investigated and yield strength, reduction of area after steel breaking and elongation were calculated. After these studies it was possible to certify that the partial substitution of vanadium by niobium did not alter significantly the basic mechanical properties of the AISI H13. (Author) [pt

  20. Some mechanical properties of borided AISI H13 and 304 steels

    International Nuclear Information System (INIS)

    Taktak, Sukru

    2007-01-01

    In the present study, mechanical properties of borides formed on AISI H13 hot work tool and AISI 304 stainless steels have been investigated. Both steels have high chromium content and have a widespread use in the engineering application. Boriding treatment was carried out in slurry salt bath consisting of borax, boric acid, and ferrosilicon at temperature range of 800-950 deg. C for 3, 5, and 7 h. X-ray diffraction analysis of boride layers on the surface of steels revealed various peaks of FeB, Fe 2 B, CrB, and Ni 3 B. Metallographic studies showed that the boride layer has a flat and smooth morphology in the 304 steel while H13 steel was a ragged morphology. The characterization of the boride layer is also carried out by means of the micro-hardness, surface roughness, adhesion, and fracture toughness studies

  1. CHARACTERIZATION OF NEW TOOL STEEL FOR ALUMINUM EXTRUSION DIES

    Directory of Open Access Journals (Sweden)

    José Britti Bacalhau

    2014-06-01

    Full Text Available Aluminum extrusion dies are an important segment of application on industrial tools steels, which are manufactured in steels based on AISI H13 steel. The main properties of steels applied to extrusion dies are: wear resistance, impact resistance and tempering resistance. The present work discusses the characteristics of a newly developed hot work steel to be used on aluminum extrusion dies. The effects of Cr and Mo contents with respect to tempering resistance and the Al addition on the nitriding response have been evaluated. From forged steel bars, Charpy impact test and characterization via EPMA have been conducted. The proposed contents of Cr, Mo, and Al have attributed to the new VEX grade a much better tempering resistance than H13, as well as a deeper and harder nitrided layer. Due to the unique characteristics, this new steel provides an interesting alternative to the aluminum extrusion companies to increase their competitiveness.

  2. Evaluation of carbon diffusion in heat treatment of H13 tool steel under different atmospheric conditions

    Directory of Open Access Journals (Sweden)

    Maziar Ramezani

    2015-04-01

    Full Text Available Although the cost of the heat treatment process is only a minor portion of the total production cost, it is arguably the most important and crucial stage on the determination of material quality. In the study of the carbon diffusion in H13 steel during austenitization, a series of heat treatment experiments had been conducted under different atmospheric conditions and length of treatment. Four austenitization atmospheric conditions were studied, i.e., heat treatment without atmospheric control, heat treatment with stainless steel foil wrapping, pack carburization heat treatment and vacuum heat treatment. The results showed that stainless steel foil wrapping could restrict decarburization process, resulting in a constant hardness profile as vacuum heat treatment does. However, the tempering characteristic between these two heat treatment methods is different. Results from the gas nitrided samples showed that the thickness and the hardness of the nitrided layer is independent of the carbon content in H13 steel.

  3. Effects of advanced laser processing on the microstructure and residual stresses of H13 tool steel

    OpenAIRE

    Trojan, Karel; Ocelík, Václav; Ganev, Nikolaj; Němeček, Stanislav; Čapek, Jiří

    2017-01-01

    The aim of this paper is to describe the effects of laser processing on the microstructure and residual stresses of laser cladded H13 tool steel on the classical construct steel S355 substrate. This research paper concludes that in this case of laser cladding, phase transformation and not shrinkage is likely to be a dominant effect on the formation of compressive residual stresses along the clad. Furthermore, martensitic structure and unequal concentration of alloying elements was observed on...

  4. Thermomechanical modelling of laser surface glazing for H13 tool steel

    Science.gov (United States)

    Kabir, I. R.; Yin, D.; Tamanna, N.; Naher, S.

    2018-03-01

    A two-dimensional thermomechanical finite element (FE) model of laser surface glazing (LSG) has been developed for H13 tool steel. The direct coupling technique of ANSYS 17.2 (APDL) has been utilised to solve the transient thermomechanical process. A H13 tool steel cylindrical cross-section has been modelled for laser power 200 W and 300 W at constant 0.2 mm beam width and 0.15 ms residence time. The model can predict temperature distribution, stress-strain increments in elastic and plastic region with time and space. The crack formation tendency also can be assumed by analysing the von Mises stress in the heat-concentrated zone. Isotropic and kinematic hardening models have been applied separately to predict the after-yield phenomena. At 200 W laser power, the peak surface temperature achieved is 1520 K which is below the melting point (1727 K) of H13 tool steel. For laser power 300 W, the peak surface temperature is 2523 K. Tensile residual stresses on surface have been found after cooling, which are in agreement with literature. Isotropic model shows higher residual stress that increases with laser power. Conversely, kinematic model gives lower residual stress which decreases with laser power. Therefore, both plasticity models could work in LSG for H13 tool steel.

  5. Influence of the ion nitriding temperature in the wear resistance of AISI H13 tool steel

    International Nuclear Information System (INIS)

    Heck, Stenio Cristaldo; Fernandes, Frederico Augusto Pires; Pereira, Ricardo Gomes; Casteletti, Luiz Carlos; Totten, George Edward

    2010-01-01

    The AISI H13 tool steel for hot work is the most used in its category. This steel was developed for injection molds and extrusion of hot metals as well as for conformation in hot presses and hammers. Plasma nitriding can improve significantly the surface properties of these steels, but the treatments conditions, such as temperature, must be optimized. In this work the influence of nitriding treatment temperature on the wear behavior of this steel is investigated. Samples of AISI H13 steel were quenched and tempered and then ion nitrided in the temperatures of 450, 550 and 650 deg C, at 4mbar pressure, during 5 hours. Samples of the treated material were characterized by optical microscopy, Vickers microhardness, x-ray analysis and wear tests. Plasma nitriding formed hard diffusion zones in all the treated samples. White layers were formed in samples treated at 550 deg C and 650 deg C. The treatment temperature of 450 deg C produced the highest hardness. Treatment temperature showed great influence in the diffusion layer thickness. X-ray analysis indicated the formation of the Fe_3N, Fe_4N and CrN phases for all temperatures, but with different concentrations. Nitriding increased significantly the AISI H13 wear resistance. (author)

  6. Tribological evaluation of surface modified H13 tool steel in warm forming of Ti–6Al–4V titanium alloy sheet

    OpenAIRE

    Wang, Dan; Li, Heng; Yang, He; Ma, Jun; Li, Guangjun

    2014-01-01

    The H13 hot-working tool steel is widely used as die material in the warm forming of Ti–6Al–4V titanium alloy sheet. However, under the heating condition, severe friction and lubricating conditions between the H13 tools and Ti–6Al–4V titanium alloy sheet would cause difficulty in guaranteeing forming quality. Surface modification may be used to control the level of friction force, reduce the friction wear and extend the service life of dies. In this paper, four surface modification methods (c...

  7. Toolpath strategy for cutter life improvement in plunge milling of AISI H13 tool steel

    Science.gov (United States)

    Adesta, E. Y. T.; Avicenna; hilmy, I.; Daud, M. R. H. C.

    2018-01-01

    Machinability of AISI H13 tool steel is a prominent issue since the material has the characteristics of high hardenability, excellent wear resistance, and hot toughness. A method of improving cutter life of AISI H13 tool steel plunge milling by alternating the toolpath and cutting conditions is proposed. Taguchi orthogonal array with L9 (3^4) resolution will be employed with one categorical factor of toolpath strategy (TS) and three numeric factors of cutting speed (Vc), radial depth of cut (ae ), and chip load (fz ). It is expected that there are significant differences for each application of toolpath strategy and each cutting condition factor toward the cutting force and tool wear mechanism of the machining process, and medial axis transform toolpath could provide a better tool life improvement by a reduction of cutting force during machining.

  8. Evaluation of carbon diffusion in heat treatment of H13 tool steel under different atmospheric conditions

    OpenAIRE

    Ramezani, Maziar; Pasang, Timotius; Chen, Zhan; Neitzert, Thomas; Au, Dominique

    2015-01-01

    Although the cost of the heat treatment process is only a minor portion of the total production cost, it is arguably the most important and crucial stage on the determination of material quality. In the study of the carbon diffusion in H13 steel during austenitization, a series of heat treatment experiments had been conducted under different atmospheric conditions and length of treatment. Four austenitization atmospheric conditions were studied, i.e., heat treatment without atmospheric contro...

  9. Designing Pulse Laser Surface Modification of H13 Steel Using Response Surface Method

    Science.gov (United States)

    Aqida, S. N.; Brabazon, D.; Naher, S.

    2011-01-01

    This paper presents a design of experiment (DOE) for laser surface modification process of AISI H13 tool steel in achieving the maximum hardness and minimum surface roughness at a range of modified layer depth. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 tool steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, overlap percentage and pulse repetition frequency (PRF). The response surface method with Box-Behnken design approach in Design Expert 7 software was used to design the H13 laser surface modification process. Metallographic study and image analysis were done to measure the modified layer depth. The modified surface roughness was measured using two-dimensional surface profilometer. The correlation of the three laser processing parameters and the modified surface properties was specified by plotting three-dimensional graph. The hardness properties were tested at 981 mN force. From metallographic study, the laser modified surface depth was between 37 μm and 150 μm. The average surface roughness recorded from the 2D profilometry was at a minimum value of 1.8 μm. The maximum hardness achieved was between 728 and 905 HV0.1. These findings are significant to modern development of hard coatings for wear resistant applications.

  10. Hardness of H13 Tool Steel After Non-isothermal Tempering

    Science.gov (United States)

    Nelson, E.; Kohli, A.; Poirier, D. R.

    2018-04-01

    A direct method to calculate the tempering response of a tool steel (H13) that exhibits secondary hardening is presented. Based on the traditional method of presenting tempering response in terms of isothermal tempering, we show that the tempering response for a steel undergoing a non-isothermal tempering schedule can be predicted. Experiments comprised (1) isothermal tempering, (2) non-isothermal tempering pertaining to a relatively slow heating to process-temperature and (3) fast-heating cycles that are relevant to tempering by induction heating. After establishing the tempering response of the steel under simple isothermal conditions, the tempering response can be applied to non-isothermal tempering by using a numerical method to calculate the tempering parameter. Calculated results are verified by the experiments.

  11. Laser surface modification of Yttria Stabilized Zirconia (YSZ) thermal barrier coating on AISI H13 tool steel substrate

    Science.gov (United States)

    Reza, M. S.; Aqida, S. N.; Ismail, I.

    2018-03-01

    This paper presents laser surface modification of plasma sprayed yttria stabilized zirconia (YSZ) coating to seal porosity defect. Laser surface modification on plasma sprayed YSZ was conducted using 300W JK300HPS Nd: YAG laser at different operating parameters. Parameters varied were laser power and pulse frequency with constant residence time. The coating thickness was measured using IM7000 inverted optical microscope and surface roughness was analysed using two-dimensional Mitutoyo Surface Roughness Tester. Surface roughness of laser surface modification of YSZ H-13 tool steel decreased significantly with increasing laser power and decreasing pulse frequency. The re-melted YSZ coating showed higher hardness properties compared to as-sprayed coating surface. These findings were significant to enhance thermal barrier coating surface integrity for dies in semi-solid processing.

  12. An investigation of improved strength and toughness of ausformed H13 steel

    International Nuclear Information System (INIS)

    Cha, Yong Chul; Yoon, Han Sang

    1986-01-01

    The effect of ausforming for AISI H13 steel was studied. Plastic deformation of metastable austenite increased the hardness and strength of the subsequently formed martensite. The increases in yield and tensile strength were proportional to the degree of austenite deformation without sacrifice of toughness, and large deformation (60%) resulted in significant increase in impact value. Furthermore, temper resistance up to 500 deg C, that is, consequent improvement in elevated-temperature strength property was demonstrated. These results can be interpreted as being attributed to the formation of cellular substructures which were fixed by alloy carbides. (Author)

  13. Cavitation resistance of 45 and 2H13 steels laser enriched with silicon carbides and hafnium

    International Nuclear Information System (INIS)

    Skodo, M.; Giren, B.; Cenian, A.

    1999-01-01

    Cavitation resistance of 45 and H13 steels with surface layers enriched with Hf and SiC compounds was investigated. All contamination elements were spread over the samples surfaces and subsequently alloyed with core material by CO 2 laser beam. Cavitation tests carried out at the rotating disk facility revealed multiple - 5 to 10 times - increase of erosion resistance of the processed materials during the incubation period of the destruction. This effect was found not to be decisively linked to obtained microhardness changes. (author)

  14. Microstructure and corrosion behaviour of pulsed plasma-nitrided AISI H13 tool steel

    International Nuclear Information System (INIS)

    Basso, Rodrigo L.O.; Pastore, Heloise O.; Schmidt, Vanessa; Baumvol, Israel J.R.; Abarca, Silvia A.C.; Souza, Fernando S. de; Spinelli, Almir; Figueroa, Carlos A.; Giacomelli, Cristiano

    2010-01-01

    The effect of pulsed plasma nitriding temperature and time on the pitting corrosion behaviour of AISI H13 tool steel in 0.9% NaCl solutions was investigated by cyclic polarization. The pitting potential (E pit ) was found to be dependent on the composition, microstructure and morphology of the surface layers, whose properties were determined by X-ray diffraction and scanning electron microscopy techniques. The best corrosion protection was observed for samples nitrided at 480 o C and 520 o C. Under such experimental conditions the E pit -values shifted up to 1.25 V in the positive direction.

  15. Conversion electron Moessbauer spectroscopy of plasma immersion ion implanted H13 tool steel

    International Nuclear Information System (INIS)

    Terwagne, G.; Hutchings, R.

    1994-01-01

    Conversion electron Moessbauer spectroscopy (CEMS) has been used to investigate nitride formation in AISI-H13 tool steel after treatment by plasma immersion ion implantation (PI 3 ) at 350 C. With only slight variation in the plasma conditions, it is possible to influence the kinetics of nitride precipitation so as to obtain nitrogen concentrations that range from those associated with ε-Fe 2 N through ε-Fe 3 N to γ'-Fe 4 N. The CEMS results enable a more definite identification of the nitrides than that obtained by glancing-angle X-ray diffraction and nuclear reaction analysis alone. (orig.)

  16. Conversion electron Mössbauer spectroscopy of plasma immersion ion implanted H13 tool steel

    Science.gov (United States)

    Terwagne, G.; Collins, G. A.; Hutchings, R.

    1994-12-01

    Conversion electron Mössbauer spectroscopy (CEMS) has been used to investigate nitride formation in AISI-H13 tool steel after treatment by plasma immersion ion implantation (PI3) at 350 °C. With only slight variation in the plasma conditions, it is possible to influence the kinetics of nitride precipitation so as to obtain nitrogen concentrations that range from those associated with ɛ-Fe2N through ɛ-Fe3N to γ'-Fe4N. The CEMS results enable a more definite identification of the nitrides than that obtained by glancing-angle X-ray diffraction and nuclear reaction analysis alone.

  17. Effects of Rare Earth on the Microstructure and Impact Toughness of H13 Steel

    Directory of Open Access Journals (Sweden)

    Jinzhu Gao

    2015-03-01

    Full Text Available Studies of H13 steel suggest that under appropriate conditions, additions of rare-earth metals (REM can significantly enhance mechanical properties, such as impact toughness. This improvement is apparently due to the formation of finer and more dispersive RE inclusions and grain refinement after REM additions. In this present work, the microstructure evolution and mechanical properties of H13 steel with rare earth additions (0, 0.015, 0.025 and 0.1 wt.% were investigated. The grain size, inclusions and fracture morphology were systematically studied by means of optical microscopy (OM, scanning electron microscopy (SEM and transmission electron microscopy (TEM. The results indicate that REM addition of 0.015 wt.% can result in good improvement of performance compared to the REM additions of 0.025 wt.% and 0.1 wt.%. It is found that the impact toughness is significantly enhanced with the addition of 0.015% REM, which can be improved 90% from 10 J to 19 J. Such an addition of REM can result in a huge volume fraction of finer and more dispersive inclusions which are extremely good to toughness.

  18. Two dimensional finite element thermal model of laser surface glazing for H13 tool steel

    Science.gov (United States)

    Kabir, I. R.; Yin, D.; Naher, S.

    2016-10-01

    A two dimensional (2D) transient thermal model with line-heat-source was developed by Finite Element Method (FEM) for laser surface glazing of H13 tool steel using commercial software-ANSYS 15. The geometry of the model was taken as a transverse circular cross-section of cylindrical specimen. Two different power levels (300W, 200W) were used with 0.2mm width of laser beam and 0.15ms exposure time. Temperature distribution, heating and cooling rates, and the dimensions of modified surface were analysed. The maximum temperatures achieved were 2532K (2259°C) and 1592K (1319°C) for laser power 300W and 200W respectively. The maximum cooling rates were 4.2×107 K/s for 300W and 2×107 K/s for 200W. Depths of modified zone increased with increasing laser power. From this analysis, it can be predicted that for 0.2mm beam width and 0.15ms time exposer melting temperature of H13 tool steel is achieved within 200-300W power range of laser beam in laser surface glazing.

  19. Structural properties of H13 tool steel parts produced with use of selective laser melting technology

    International Nuclear Information System (INIS)

    Šafka, J; Ackermann, M; Voleský, L

    2016-01-01

    This paper deals with establishing of building parameters for 1.2344 (H13) tool steel processed using Selective Laser Melting (SLM) technology with layer thickness of 50 µm. In the first part of the work, testing matrix of models in the form of a cube with chamfered edge were built under various building parameters such as laser scanning speed and laser power. Resulting models were subjected to set of tests including measurement of surface roughness, inspection of inner structure with aid of Light Optical Microscopy and Scanning Electron Microscopy and evaluation of micro-hardness. These tests helped us to evaluate an influence of changes in building strategy to the properties of the resulting model. In the second part of the work, mechanical properties of the H13 steel were examined. For this purpose, the set of samples in the form of “dog bone” were printed under three different alignments towards the building plate and tested on universal testing machine. Mechanical testing of the samples should then reveal if the different orientation and thus different layering of the material somehow influence its mechanical properties. For this type of material, the producer provides the parameters for layer thickness of 30 µm only. Thus, our 50 µm building strategy brings shortening of the building time which is valuable especially for large models. Results of mechanical tests show slight variation in mechanical properties for various alignment of the sample. (paper)

  20. Modelling of Tool Wear and Residual Stress during Machining of AISI H13 Tool Steel

    Science.gov (United States)

    Outeiro, José C.; Umbrello, Domenico; Pina, José C.; Rizzuti, Stefania

    2007-05-01

    Residual stresses can enhance or impair the ability of a component to withstand loading conditions in service (fatigue, creep, stress corrosion cracking, etc.), depending on their nature: compressive or tensile, respectively. This poses enormous problems in structural assembly as this affects the structural integrity of the whole part. In addition, tool wear issues are of critical importance in manufacturing since these affect component quality, tool life and machining cost. Therefore, prediction and control of both tool wear and the residual stresses in machining are absolutely necessary. In this work, a two-dimensional Finite Element model using an implicit Lagrangian formulation with an automatic remeshing was applied to simulate the orthogonal cutting process of AISI H13 tool steel. To validate such model the predicted and experimentally measured chip geometry, cutting forces, temperatures, tool wear and residual stresses on the machined affected layers were compared. The proposed FE model allowed us to investigate the influence of tool geometry, cutting regime parameters and tool wear on residual stress distribution in the machined surface and subsurface of AISI H13 tool steel. The obtained results permit to conclude that in order to reduce the magnitude of surface residual stresses, the cutting speed should be increased, the uncut chip thickness (or feed) should be reduced and machining with honed tools having large cutting edge radii produce better results than chamfered tools. Moreover, increasing tool wear increases the magnitude of surface residual stresses.

  1. Structural properties of H13 tool steel parts produced with use of selective laser melting technology

    Science.gov (United States)

    Šafka, J.; Ackermann, M.; Voleský, L.

    2016-04-01

    This paper deals with establishing of building parameters for 1.2344 (H13) tool steel processed using Selective Laser Melting (SLM) technology with layer thickness of 50 µm. In the first part of the work, testing matrix of models in the form of a cube with chamfered edge were built under various building parameters such as laser scanning speed and laser power. Resulting models were subjected to set of tests including measurement of surface roughness, inspection of inner structure with aid of Light Optical Microscopy and Scanning Electron Microscopy and evaluation of micro-hardness. These tests helped us to evaluate an influence of changes in building strategy to the properties of the resulting model. In the second part of the work, mechanical properties of the H13 steel were examined. For this purpose, the set of samples in the form of “dog bone” were printed under three different alignments towards the building plate and tested on universal testing machine. Mechanical testing of the samples should then reveal if the different orientation and thus different layering of the material somehow influence its mechanical properties. For this type of material, the producer provides the parameters for layer thickness of 30 µm only. Thus, our 50 µm building strategy brings shortening of the building time which is valuable especially for large models. Results of mechanical tests show slight variation in mechanical properties for various alignment of the sample.

  2. Surface modification of AISI H13 tool steel by laser cladding with NiTi powder

    Science.gov (United States)

    Norhafzan, B.; Aqida, S. N.; Chikarakara, E.; Brabazon, D.

    2016-04-01

    This paper presents laser cladding of NiTi powder on AISI H13 tool steel surface for surface properties enhancement. The cladding process was conducted using Rofin DC-015 diffusion-cooled CO2 laser system with wavelength of 10.6 µm. NiTi powder was pre-placed on H13 tool steel surface. The laser beam was focused with a spot size of 90 µm on the sample surface. Laser parameters were set to 1515 and 1138 W peak power, 18 and 24 % duty cycle and 2300-3500 Hz laser pulse repetition frequency. Hardness properties of the modified layer were characterized by Wilson Hardness tester. Metallographic study and chemical composition were conducted using field emission scanning electron microscope and energy-dispersive X-ray spectrometer (EDXS) analysis. Results showed that hardness of NiTi clad layer increased three times that of the substrate material. The EDXS analysis detected NiTi phase presence in the modified layer up to 9.8 wt%. The metallographic study shows high metallurgical bonding between substrate and modified layer. These findings are significant to both increased hardness and erosion resistance of high-wear-resistant components and elongating their lifetime.

  3. An investigation of phase transformation and crystallinity in laser surface modified H13 steel

    Science.gov (United States)

    Aqida, S. N.; Brabazon, D.; Naher, S.

    2013-03-01

    This paper presents a laser surface modification process of AISI H13 tool steel using 0.09, 0.2 and 0.4 mm size of laser spot with an aim to increase hardness properties. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 tool steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, overlap percentage and pulse repetition frequency (PRF). X-ray diffraction analysis (XRD) was conducted to measure crystallinity of the laser-modified surface. X-ray diffraction patterns of the samples were recorded using a Bruker D8 XRD system with Cu K α ( λ=1.5405 Å) radiation. The diffraction patterns were recorded in the 2 θ range of 20 to 80°. The hardness properties were tested at 981 mN force. The laser-modified surface exhibited reduced crystallinity compared to the un-processed samples. The presence of martensitic phase was detected in the samples processed using 0.4 mm spot size. Though there was reduced crystallinity, a high hardness was measured in the laser-modified surface. Hardness was increased more than 2.5 times compared to the as-received samples. These findings reveal the phase source of the hardening mechanism and grain composition in the laser-modified surface.

  4. Parametric Investigation of Diode and CO2 Laser in Direct Metal Deposition of H13 Tool Steel on Copper Substrate

    OpenAIRE

    M. Khalid Imran; Syed Masood; Milan Brandt; Sudip Bhattacharya; Jyotirmoy Mazumder

    2011-01-01

    In the present investigation, H13 tool steel has been deposited on copper alloy substrate using both CO2 and diode laser. A detailed parametric analysis has been carried out in order to find out optimum processing zone for coating defect free H13 tool steel on copper alloy substrate. Followed by parametric optimization, the microstructure and microhardness of the deposited clads have been evaluated. SEM micrographs revealed dendritic microstructure in both clads. However,...

  5. Tribological evaluation of surface modified H13 tool steel in warm forming of Ti–6Al–4V titanium alloy sheet

    Directory of Open Access Journals (Sweden)

    Wang Dan

    2014-08-01

    Full Text Available The H13 hot-working tool steel is widely used as die material in the warm forming of Ti–6Al–4V titanium alloy sheet. However, under the heating condition, severe friction and lubricating conditions between the H13 tools and Ti–6Al–4V titanium alloy sheet would cause difficulty in guaranteeing forming quality. Surface modification may be used to control the level of friction force, reduce the friction wear and extend the service life of dies. In this paper, four surface modification methods (chromium plating, TiAlN coating, surface polishing and nitriding treatment were applied to the H13 surfaces. Taking the coefficient of friction (CoF and the wear degree as evaluation indicators, the high-temperature tribological behavior of the surface modified H13 steel was experimentally investigated under different tribological conditions. The results of this study indicate that the tribological properties of the TiAlN coating under dry friction condition are better than the others for a wide range of temperature (from room temperature to 500 °C, while there is little difference of tribological properties between different surface modifications under graphite lubricated condition, and the variation law of CoF with temperature under graphite lubricated is opposite to that under the dry friction.

  6. Modeling of the flow stress for AISI H13 Tool Steel during Hard Machining Processes

    Science.gov (United States)

    Umbrello, Domenico; Rizzuti, Stefania; Outeiro, José C.; Shivpuri, Rajiv

    2007-04-01

    In general, the flow stress models used in computer simulation of machining processes are a function of effective strain, effective strain rate and temperature developed during the cutting process. However, these models do not adequately describe the material behavior in hard machining, where a range of material hardness between 45 and 60 HRC are used. Thus, depending on the specific material hardness different material models must be used in modeling the cutting process. This paper describes the development of a hardness-based flow stress and fracture models for the AISI H13 tool steel, which can be applied for range of material hardness mentioned above. These models were implemented in a non-isothermal viscoplastic numerical model to simulate the machining process for AISI H13 with various hardness values and applying different cutting regime parameters. Predicted results are validated by comparing them with experimental results found in the literature. They are found to predict reasonably well the cutting forces as well as the change in chip morphology from continuous to segmented chip as the material hardness change.

  7. Modeling of the flow stress for AISI H13 Tool Steel during Hard Machining Processes

    International Nuclear Information System (INIS)

    Umbrello, Domenico; Rizzuti, Stefania; Outeiro, Jose C.; Shivpuri, Rajiv

    2007-01-01

    In general, the flow stress models used in computer simulation of machining processes are a function of effective strain, effective strain rate and temperature developed during the cutting process. However, these models do not adequately describe the material behavior in hard machining, where a range of material hardness between 45 and 60 HRC are used. Thus, depending on the specific material hardness different material models must be used in modeling the cutting process. This paper describes the development of a hardness-based flow stress and fracture models for the AISI H13 tool steel, which can be applied for range of material hardness mentioned above. These models were implemented in a non-isothermal viscoplastic numerical model to simulate the machining process for AISI H13 with various hardness values and applying different cutting regime parameters. Predicted results are validated by comparing them with experimental results found in the literature. They are found to predict reasonably well the cutting forces as well as the change in chip morphology from continuous to segmented chip as the material hardness change

  8. Direct Metal Deposition of H13 Tool Steel on Copper Alloy Substrate: Parametric Investigation

    Science.gov (United States)

    Imran, M. Khalid; Masood, S. H.; Brandt, Milan

    2015-12-01

    Over the past decade, researchers have demonstrated interest in tribology and prototyping by the laser aided material deposition process. Laser aided direct metal deposition (DMD) enables the formation of a uniform clad by melting the powder to form desired component from metal powder materials. In this research H13 tool steel has been used to clad on a copper alloy substrate using DMD. The effects of laser parameters on the quality of DMD deposited clad have been investigated and acceptable processing parameters have been determined largely through trial-and-error approaches. The relationships between DMD process parameters and the product characteristics such as porosity, micro-cracks and microhardness have been analysed using scanning electron microscope (SEM), image analysis software (ImageJ) and microhardness tester. It has been found that DMD parameters such as laser power, powder mass flow rate, feed rate and focus size have an important role in clad quality and crack formation.

  9. Optimization and Simulation of SLM Process for High Density H13 Tool Steel Parts

    Science.gov (United States)

    Laakso, Petri; Riipinen, Tuomas; Laukkanen, Anssi; Andersson, Tom; Jokinen, Antero; Revuelta, Alejandro; Ruusuvuori, Kimmo

    This paper demonstrates the successful printing and optimization of processing parameters of high-strength H13 tool steel by Selective Laser Melting (SLM). D-Optimal Design of Experiments (DOE) approach is used for parameter optimization of laser power, scanning speed and hatch width. With 50 test samples (1×1×1cm) we establish parameter windows for these three parameters in relation to part density. The calculated numerical model is found to be in good agreement with the density data obtained from the samples using image analysis. A thermomechanical finite element simulation model is constructed of the SLM process and validated by comparing the calculated densities retrieved from the model with the experimentally determined densities. With the simulation tool one can explore the effect of different parameters on density before making any printed samples. Establishing a parameter window provides the user with freedom for parameter selection such as choosing parameters that result in fastest print speed.

  10. The relationship of cutting force with hole quality in drilling process of AISI H13 steel

    Directory of Open Access Journals (Sweden)

    Tekaüt İsmail

    2017-01-01

    Full Text Available The harmony of the drilling machine-cutting tool-work piece is very important for producing the machine part with the ideal dimensions. For this purpose in this study, the effect of cutting forces on hole quality (surface roughness, diameter deviation and circular deviation was investigated by 14 mm diameter uncoated and (AlCrN monolayer coated carbide drills for drilling AISI H13 hot work tool steel on vertical machining center. Four different cutting speeds (60, 75, 90 and 108 m / min and three different feed rates (0.15, 0.20 and 0.25 mm / rev were used in the experiments. Cutting forces have been found to be effective in improving hole quality. Better hole quality has obtained with coated drills than uncoated drills in experiments. It has been observed that coated drills have the effect of improving the hole quality due to the operation with less cutting force and better chip evacuation.

  11. Effect of the Ultrasonic Nanocrystalline Surface Modification (UNSM on Bulk and 3D-Printed AISI H13 Tool Steels

    Directory of Open Access Journals (Sweden)

    In-Sik Cho

    2017-11-01

    Full Text Available A comparative study of the microstructure, hardness, and tribological properties of two different AISI H13 tool steels—classified as the bulk with no heat treatment steel or the 3D-printed steel—was undertaken. Both samples were subjected to ultrasonic nanocrystalline surface modification (UNSM to further enhance their mechanical properties and improve their tribological behavior. The objective of this study was to compare the mechanical properties and tribological behavior of these tool steels since steel can exhibit a wide variety of mechanical properties depending on different manufacturing processes. The surface hardness of the samples was measured using a micro-Vickers hardness tester. The hardness of the 3D-printed AISI H13 tool steel was found to be much higher than that of the bulk one. The surface morphology of the samples was characterized by electron backscattered diffraction (EBSD in order to analyze the grain size and number of fractions with respect to the misorientation angle. The results revealed that the grain size of the 3D-printed AISI H13 tool steel was less than 0.5 μm, whereas that of the bulk tool steel was greater than 4 μm. The number of fractions of the bulk tool steel was about 0.5 μm at a low misorientation angle, and it decreased gradually with increasing misorientation angle. The low-angle grain boundary (LAGB and high-angle grain boundary (HAGB of the bulk sample were about 21% and 79%, respectively, and those of the 3D-printed sample were about 8% and 92%, respectively. Moreover, the friction and wear behavior of the UNSM-treated AISI H13 tool steel specimen was better than those of the untreated one. This study demonstrated the capability of 3D-printed AISI H13 tool steel to exhibit excellent mechanical and tribological properties for industrial applications.

  12. Microstructure and phase transformations in laser clad CrxSy/Ni coating on H13 steel

    Science.gov (United States)

    Lei, Yiwen; Sun, Ronglu; Tang, Ying; Niu, Wei

    2015-03-01

    Laser cladding was carried out onto H13 steel with preplaced NiCrBSi+Ni/MoS2 powders using CO2 laser under the optimized experimental parameters of laser power 2 kW, scanning velocity 6 mm/s and laser beam diameter 3 mm. An X-ray diffractometer and scanning electron microscope with energy dispersive spectroscopy were applied to analyze the microstructure and phase compositions of the coating. Thermodynamic calculation was performed with Thermo-Calc software on the basis of a commercially available Ni-based Alloys' database. The experimental results show that MoS2 decomposed and S reacted with Cr to form nonstoichiometric CrxSy during the laser cladding process. The coating consists of spherical CrxSy particles, primary γ-Ni dendrite, interdendritic eutectic (γ-Ni+NiMo) and precipitated NiMo. The precipitated NiMo was fine and uniformly distributed in primary γ-Ni dendrite. The calculated results and experimental data indicate that the solidification process in the coating during laser cladding process was liquid→liquid+CrxSy→ liquid+CrxSy+γ-Ni→liquid+CrxSy+γ-Ni+ eutectic (γ-Ni+NiMo). A solid state phase transformation (fine and uniformly distributed NiMo precipitated from γ-Ni) occurred after the solidification process. The calculations agree well with the experimental data and it is helpful to understand the phase transformation and microstructure evolution in the coating.

  13. Temperature and composition profile during double-track laser cladding of H13 tool steel

    Science.gov (United States)

    He, X.; Yu, G.; Mazumder, J.

    2010-01-01

    Multi-track laser cladding is now applied commercially in a range of industries such as automotive, mining and aerospace due to its diversified potential for material processing. The knowledge of temperature, velocity and composition distribution history is essential for a better understanding of the process and subsequent microstructure evolution and properties. Numerical simulation not only helps to understand the complex physical phenomena and underlying principles involved in this process, but it can also be used in the process prediction and system control. The double-track coaxial laser cladding with H13 tool steel powder injection is simulated using a comprehensive three-dimensional model, based on the mass, momentum, energy conservation and solute transport equation. Some important physical phenomena, such as heat transfer, phase changes, mass addition and fluid flow, are taken into account in the calculation. The physical properties for a mixture of solid and liquid phase are defined by treating it as a continuum media. The velocity of the laser beam during the transition between two tracks is considered. The evolution of temperature and composition of different monitoring locations is simulated.

  14. The Characteristics and Generating Mechanism of Large Precipitates in Ti-Containing H13 Tool Steel

    Science.gov (United States)

    Xie, You; Cheng, Guoguang; Chen, Lie; Zhang, Yandong; Yan, Qingzhong

    2017-02-01

    The characteristics of large precipitates in H13 tool steel with 0.015wt% Ti were studied. The result shows that three types of phases larger than 1 μm exist in the as-cast ingot, that is, (Ti, V) (C, N) type phase, (V, Mo, Cr)C type phase and sulfide. (Ti, V) (C, N) type phase could be further classified as the homogeneous Ti-rich one and the Ti-V-rich one in which Ti/V ratio gradually changes. (V, Mo, Cr)C type phase contains the V-rich one and the Mo-Cr-rich one. The compositional characteristics in all of them have little relation with the cutting position or cooling rate. The precipitating process could be well described through calculation by Thermo-Calc software. During solidification, the primary phase (Ti, V)(C, N) first starts to precipitate in the form of Ti-rich carbonitride. With the development of solidification, the ratio of Ti decreases and that of V increases. Then the primary phase Ti-V-rich (Ti, V)(C, N) and V-rich (V, Mo, Cr)C appears successively. Mo-Cr-rich (V, Mo, Cr)C phase does not precipitate until the solidification process reaches to the end. Sulfide precipitates before (V, Mo, Cr)C type phase and it could act as the nucleus of (V, Mo, Cr)C.

  15. Optimization of Composition and Heat Treating of Die Steels for Extended Lifetime; FINAL

    International Nuclear Information System (INIS)

    David Schwam; John F, Wallace; Quanyou Zhou

    2002-01-01

    An ''average'' die casting die costs fifty thousand dollars. A die used in making die cast aluminum engine blocks can cost well over one million dollars. These costs provide a strong incentive for extension of die life. While vacuum quenched Premium Grade H13 dies have become the most widely used in the United States, tool makers and die casters are constantly searching for new steels and heat treating procedures to extend die life. This project was undertaken to investigate the effects of composition and heat treating on die life and optimize these parameters

  16. Determination of type, magnitude and direction of residual stresses generated in the welding of AISI H-13 steel with the hole drilling method

    International Nuclear Information System (INIS)

    Mejia; I; Maldonado, C; Bedolla, A; Velez, M; Medina, A; Bejar, L

    2006-01-01

    AISI H-13 steel is considered to be a highly ultra resistant steel because its resistance to stress surpasses 1380 MPa. This steel is widely used in tools that heavily used, especially under high temperatures, such as: awls, molds for pressing, extrusion dies, extrusion tools from heat impact, tools for producing screws, bolts, rivets and taps, molds for centrifugal smelting, tools for presses with shaped pieces, knives for hot cutting, among others. The weldability of AISI H-13 steel is generally poor, but it is possible if the proper precautions are taken. Cracking is perhaps the factor that most limits the weldability of AISI H-13 steel. The tendency to crack during welding for this type of steel occurs in the base metal and the zone close to the supporting material (cold cracking). The interlayer covering technique is used in the repair, welding and recovery of pieces of high alloy steels in order to avoid cracking and to lower the residual stresses generated by obstructed contraction and martensitic transformation. This work defined the type, magnitude and direction of residual stresses at different distances starting from the center of the welded union on the 25.4 mm thick AISI H-13 steel sheet. The welding was carried out in a test piece with Y-Groove geometry following JIS Z 3158 standard, using the SMAW process and an AISI 312 stainless steel interlayer between the base metal and the supporting metal. The hole-drilling method was used to measure the type, magnitude and direction of residual stresses using extensometric gauge rosette CEA-06-062UM-120 and CEA-06-062RE-120 following the guidelines established by ASTM E 837 standard. Based on the relaxed deformations that were measured, the type, magnitude and direction of residual stresses were determined with the H-DRILL residual stress program for biaxial condition. The results indicate that under these welding conditions the residual strains at different distances from the welded union are from stress and

  17. High Power Picosecond Laser Surface Micro-texturing of H13 Tool Steel and Pattern Replication onto ABS Plastics via Injection Moulding

    Science.gov (United States)

    Otanocha, Omonigho B.; Li, Lin; Zhong, Shan; Liu, Zhu

    2016-03-01

    H13 tool steels are often used as dies and moulds for injection moulding of plastic components. Certain injection moulded components require micro-patterns on their surfaces in order to modify the physical properties of the components or for better mould release to reduce mould contamination. With these applications it is necessary to study micro-patterning to moulds and to ensure effective pattern transfer and replication onto the plastic component during moulding. In this paper, we report an investigation into high average powered (100 W) picosecond laser interactions with H13 tool steel during surface micro-patterning (texturing) and the subsequent pattern replication on ABS plastic material through injection moulding. Design of experiments and statistical modelling were used to understand the influences of laser pulse repetition rate, laser fluence, scanning velocity, and number of scans on the depth of cut, kerf width and heat affected zones (HAZ) size. The characteristics of the surface patterns are analysed. The process parameter interactions and significance of process parameters on the processing quality and efficiency are characterised. An optimum operating window is recommended. The transferred geometry is compared with the patterns generated on the dies. A discussion is made to explain the characteristics of laser texturing and pattern replication on plastics.

  18. A Method Based on Semi-Solid Forming for Eliminating Coarse Dendrites and Shrinkage Porosity of H13 Tool Steel

    Directory of Open Access Journals (Sweden)

    Yifeng Guo

    2018-04-01

    Full Text Available A method called forging solidifying metal (FSM, which is applied for eliminating coarse dendrites and shrinkage porosity defects of ferrous alloys was proposed based on semi-solid forming technology (SSF. To verify its feasibility, the effects of liquid fraction (FL on the microstructure of the deformed H13 steel were investigated experimentally. The coarse dendrites structure still existed and cracks appeared when the 0.1/s 50% FSM method was carried out at ~20% FL. What is significantly different from that is, the elimination of the coarse dendrites structure and shrinkage porosity defects became more significant, when this method was conducted at the end of solidification (FL < 10%. The microstructure of H13 steel was significantly refined and also became dense in such condition.

  19. Effect of cryogenic treatment on microstructure, mechanical and wear behaviors of AISI H13 hot work tool steel

    Science.gov (United States)

    Koneshlou, Mahdi; Meshinchi Asl, Kaveh; Khomamizadeh, Farzad

    2011-01-01

    This paper focuses on the effects of low temperature (subzero) treatments on microstructure and mechanical properties of H13 hot work tool steel. Cryogenic treatment at -72 °C and deep cryogenic treatment at -196 °C were applied and it was found that by applying the subzero treatments, the retained austenite was transformed to martensite. As the temperature was decreased more retained austenite was transformed to martensite and it also led to smaller and more uniform martensite laths distributed in the microstructure. The deep cryogenic treatment also resulted in precipitation of more uniform and very fine carbide particles. The microstructural modification resulted in a significant improvement on the mechanical properties of the H13 tool steel.

  20. Effect of coatings obtanied by sputtering of chromium catode on the corrosion resistance of AISI H13 steel

    International Nuclear Information System (INIS)

    Sandoval, A; Peña, D; Piratoba, U

    2013-01-01

    Corrosion resistance of coatings obtained by sputtering a chromium target were evaluated. The films were deposited on substrates of disk-shaped AISI H13 steel. By means of potentiodynamic polarization curves were able to determine the current density vs. potential for the coated and uncoated substrate and the difference in the corrosion potential Ecorr. All samples with coating showed an increase in Ecorr respect to substrate. The electrochemical tests were conducted in an electrolytic solution of 3% NaCl

  1. Microstructure and Mechanical Properties of Laser Clad and Post-cladding Tempered AISI H13 Tool Steel

    Science.gov (United States)

    Telasang, Gururaj; Dutta Majumdar, Jyotsna; Wasekar, Nitin; Padmanabham, G.; Manna, Indranil

    2015-05-01

    This study reports a detailed investigation of the microstructure and mechanical properties (wear resistance and tensile strength) of hardened and tempered AISI H13 tool steel substrate following laser cladding with AISI H13 tool steel powder in as-clad and after post-cladding conventional bulk isothermal tempering [at 823 K (550 °C) for 2 hours] heat treatment. Laser cladding was carried out on AISI H13 tool steel substrate using a 6 kW continuous wave diode laser coupled with fiber delivering an energy density of 133 J/mm2 and equipped with a co-axial powder feeding nozzle capable of feeding powder at the rate of 13.3 × 10-3 g/mm2. Laser clad zone comprises martensite, retained austenite, and carbides, and measures an average hardness of 600 to 650 VHN. Subsequent isothermal tempering converted the microstructure into one with tempered martensite and uniform dispersion of carbides with a hardness of 550 to 650 VHN. Interestingly, laser cladding introduced residual compressive stress of 670 ± 15 MPa, which reduces to 580 ± 20 MPa following isothermal tempering. Micro-tensile testing with specimens machined from the clad zone across or transverse to cladding direction showed high strength but failure in brittle mode. On the other hand, similar testing with samples sectioned from the clad zone parallel or longitudinal to the direction of laser cladding prior to and after post-cladding tempering recorded lower strength but ductile failure with 4.7 and 8 pct elongation, respectively. Wear resistance of the laser surface clad and post-cladding tempered samples (evaluated by fretting wear testing) registered superior performance as compared to that of conventional hardened and tempered AISI H13 tool steel.

  2. Method of treating tool steel die materials

    International Nuclear Information System (INIS)

    Cook, C.S.; Damon, S.

    1981-01-01

    In a method of hardening pilger dies to provide a hard case containing residual compressive stresses and tough body, the tool steel die is heated to the austenitizing temperature range, followed by selectively removing heat from the die at a predetermined faster rate in the direction of the desired case than the rate of heat removal from the balance of the die, and thereafter tempering the die. The invention provides a fully hardened and tempered case on the working surface of the die and a tough body in the balance of the die, usually of lower hardness. (author)

  3. Effect of laser absorption on picosecond laser ablation of Cr12MoV mold steel, 9Cr18 stainless steel and H13A cemented carbide

    Science.gov (United States)

    Wu, Baoye; Liu, Peng; Wang, Xizhao; Zhang, Fei; Deng, Leimin; Duan, Jun; Zeng, Xiaoyan

    2018-05-01

    Due to excellent properties, Cr12MoV mold steel, 9Cr18 stainless steel and H13A cemented carbide are widely used in industry. In this paper, the effect of absorption of laser light on ablation efficiency and roughness have been studied using a picosecond pulse Nd:YVO4 laser. The experimental results reveal that laser wavelength, original surface roughness and chemical composition play an important role in controlling ablation efficiency and roughness. Firstly, higher ablation efficiency with lower surface roughness is achieved on the ablation of 9Cr18 at 532, comparing with 1064 nm. Secondly, the ablation efficiency increases while the Ra of the ablated region decreases with the decrease of original surface roughness on ablation of Cr12MoV mold steel at 532 nm. Thirdly, the ablation efficiency of H13A cemented carbide is much higher than 9Cr18 stainless steel and Cr12MoV mold steel at 1064 nm. Scanning electron microscopy images reveals the formation of pores on the surface of 9Cr18 stainless steel and Cr12MoV mold steel at 532 nm while no pores are formed at 1064 nm. As to H13A cemented carbide, worm-like structure is formed at 1064 nm. The synergetic effects of the heat accumulation, plasma shielding and ablation threshold on laser ablation efficiency and machining quality were analyzed and discussed systematically in this paper.

  4. Milled Die Steel Surface Roughness Correlation with Steel Sheet Friction

    DEFF Research Database (Denmark)

    Berglund, J.; Brown, C.A.; Rosén, B.-G.

    2010-01-01

    This work investigates correlations between the surface topography ofmilled steel dies and friction with steel sheet. Several die surfaces were prepared by milling. Friction was measured in bending under tension testing. Linear regression coefficients (R2) between the friction and texture...

  5. The thermal fatigue resistance of vermicular cast iron coupling with H13 steel units by cast-in process

    International Nuclear Information System (INIS)

    Wang, Chengtao; Zhou, Hong; Lin, Peng Yu; Sun, Na; Guo, Qingchun; Zhang, Peng; Yu, Jiaxiang; Liu, Yan; Wang, Mingxing; Ren, Luquan

    2010-01-01

    This paper focuses on improving the thermal fatigue resistance on the surface of vermicular cast iron coupling with inserted H13 steel blocks that had different cross sections, by cast-in processing. The microstructure of bionic units was examined by scanning electron microscope. Micro-hardness and thermal fatigue resistance of bionic samples with varied cross sections and spacings were investigated, respectively. Results show that a marked metallurgical bonding zone was produced at interface between the inserted H13 steel block and the parent material - a unique feature of the bionic structure in the vermicular cast iron samples. The micro-hardness of the bionic samples has been significantly improved. Thermal resistance of the samples with the circular cross section was the highest and the bionics sample with spacing of 2 mm spacing had a much longer thermal fatigue life, thus resulting in the improvement for the thermal fatigue life of the bionic samples, due to the efficient preclusion for the generation and propagation of crack at the interface of H13 block and the matrix.

  6. Influence of Powder Bed Preheating on Microstructure and Mechanical Properties of H13 Tool Steel SLM Parts

    Science.gov (United States)

    Mertens, R.; Vrancken, B.; Holmstock, N.; Kinds, Y.; Kruth, J.-P.; Van Humbeeck, J.

    Powder bed preheating is a promising development in selective laser melting (SLM), mainly applied to avoid large thermal stresses in the material. This study analyses the effect of in-process preheating on microstructure, mechanical properties and residual stresses during SLM of H13 tool steel. Sample parts are produced without any preheating and are compared to the corresponding parts made with preheating at 100°, 200°, 300°, and 400°C. Interestingly, internal stresses at the top surface of the parts evolve from compressive (-324MPa) without preheating to tensile stresses (371MPa) with preheating at 400°C. Nevertheless, application of powder bed preheating results in a more homogeneous microstructure with better mechanical properties compared to H13 SLM parts produced without preheating. The fine bainitic microstructure leads to hardness values of 650-700Hv and ultimate tensile strength of 1965MPa, which are comparable to or even better than those of conventionally made and heat treated H13 tool steel.

  7. Influence of Thermal Homogenization Treatment on Structure and Impact Toughness of H13 ESR Steel

    Institute of Scientific and Technical Information of China (English)

    MA Dang-shen; ZHOU Jian; CHEN Zai-zhi; ZHANG Zhong-kan; CHEN Qi-an; LI De-hui

    2009-01-01

    The as-cast microstrueture of H13 ESR ingot and the influence of high temperature diffusion treatment on the structure and impact toughness have been investigated. The results show that the dendrite arm spacing gradually becomes wide from the surface to the center of ingot, and the large primary carbide particles always exist in interdendritic segregation areas; by means of high temperature diffusion treatment of ingot prior to hot forging, the banded segregation is nearly eliminated, the annealed structure is more uniform and the isotropic properties have been improved remarkably.

  8. Wear and Adhesive Failure of Al2O3 Powder Coating Sprayed onto AISI H13 Tool Steel Substrate

    Science.gov (United States)

    Amanov, Auezhan; Pyun, Young-Sik

    2016-07-01

    In this study, an alumina (Al2O3) ceramic powder was sprayed onto an AISI H13 hot-work tool steel substrate that was subjected to sanding and ultrasonic nanocrystalline surface modification (UNSM) treatment processes. The significance of the UNSM technique on the adhesive failure of the Al2O3 coating and on the hardness of the substrate was investigated. The adhesive failure of the coating sprayed onto sanded and UNSM-treated substrates was investigated by a micro-scratch tester at an incremental load. It was found, based on the obtained results, that the coating sprayed onto the UNSM-treated substrate exhibited a better resistance to adhesive failure in comparison with that of the coating sprayed onto the sanded substrate. Dry friction and wear property of the coatings sprayed onto the sanded and UNSM-treated substrates were assessed by means of a ball-on-disk tribometer against an AISI 52100 steel ball. It was demonstrated that the UNSM technique controllably improved the adhesive failure of the Al2O3 coating, where the critical load was improved by about 31%. Thus, it is expected that the application of the UNSM technique to an AISI H13 tool steel substrate prior to coating may delay the adhesive failure and improve the sticking between the coating and the substrate thanks to the modified and hardened surface.

  9. Effect of biomimetic non-smooth unit morphology on thermal fatigue behavior of H13 hot-work tool steel

    Science.gov (United States)

    Meng, Chao; Zhou, Hong; Cong, Dalong; Wang, Chuanwei; Zhang, Peng; Zhang, Zhihui; Ren, Luquan

    2012-06-01

    The thermal fatigue behavior of hot-work tool steel processed by a biomimetic coupled laser remelting process gets a remarkable improvement compared to untreated sample. The 'dowel pin effect', the 'dam effect' and the 'fence effect' of non-smooth units are the main reason of the conspicuous improvement of the thermal fatigue behavior. In order to get a further enhancement of the 'dowel pin effect', the 'dam effect' and the 'fence effect', this study investigated the effect of different unit morphologies (including 'prolate', 'U' and 'V' morphology) and the same unit morphology in different sizes on the thermal fatigue behavior of H13 hot-work tool steel. The results showed that the 'U' morphology unit had the optimum thermal fatigue behavior, then the 'V' morphology which was better than the 'prolate' morphology unit; when the unit morphology was identical, the thermal fatigue behavior of the sample with large unit sizes was better than that of the small sizes.

  10. Characterization of an AISI H-13 steel for work in hot

    International Nuclear Information System (INIS)

    Godinez, J.; Robles, E.

    1998-01-01

    Two materials were acquired which elaborated through secondary refining processes known as electroslag refusing (ESR) and electric arc in vacuum refusing (VAR) were acquired. These materials were thermically treated, for subsequently to determine their mechanical properties in longitudinal and transversal directions with respect to rolling direction, moreover they were characterized through scanning electron microscopy and X-ray diffraction determining microstructure, carbides and non-metallic inclusions. The results of the mechanical essays allowed to evaluate the fracture toughness to this steel by the Barsom and Rolfe method. (Author)

  11. Characterization of an AISI H-13 steel for work in hot; Caracterizacion del acero H-13 AISI para trabajado en caliente

    Energy Technology Data Exchange (ETDEWEB)

    Godinez, J.; Robles, E. [Instituto Nacional de Investigaciones Nucleares, Departamento de Sintesis y Caracterizacion de Materiales, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1998-07-01

    Two materials were acquired which elaborated through secondary refining processes known as electroslag refusing (ESR) and electric arc in vacuum refusing (VAR) were acquired. These materials were thermically treated, for subsequently to determine their mechanical properties in longitudinal and transversal directions with respect to rolling direction, moreover they were characterized through scanning electron microscopy and X-ray diffraction determining microstructure, carbides and non-metallic inclusions. The results of the mechanical essays allowed to evaluate the fracture toughness to this steel by the Barsom and Rolfe method. (Author)

  12. Interface bonding of NiCrAlY coating on laser modified H13 tool steel surface

    Science.gov (United States)

    Reza, M. S.; Aqida, S. N.; Ismail, I.

    2016-06-01

    Bonding strength of thermal spray coatings depends on the interfacial adhesion between bond coat and substrate material. In this paper, NiCrAlY (Ni-164/211 Ni22 %Cr10 %Al1.0 %Y) coatings were developed on laser modified H13 tool steel surface using atmospheric plasma spray (APS). Different laser peak power, P p, and duty cycle, DC, were investigated in order to improve the mechanical properties of H13 tool steel surface. The APS spraying parameters setting for coatings were set constant. The coating microstructure near the interface was analyzed using IM7000 inverted optical microscope. Interface bonding of NiCrAlY was investigated by interfacial indentation test (IIT) method using MMT-X7 Matsuzawa Hardness Tester Machine with Vickers indenter. Diffusion of atoms along NiCrAlY coating, laser modified and substrate layers was investigated by energy-dispersive X-ray spectroscopy (EDXS) using Hitachi Tabletop Microscope TM3030 Plus. Based on IIT method results, average interfacial toughness, K avg, for reference sample was 2.15 MPa m1/2 compared to sample L1 range of K avg from 6.02 to 6.96 MPa m1/2 and sample L2 range of K avg from 2.47 to 3.46 MPa m1/2. Hence, according to K avg, sample L1 has the highest interface bonding and is being laser modified at lower laser peak power, P p, and higher duty cycle, DC, prior to coating. The EDXS analysis indicated the presence of Fe in the NiCrAlY coating layer and increased Ni and Cr composition in the laser modified layer. Atomic diffusion occurred in both coating and laser modified layers involved in Fe, Ni and Cr elements. These findings introduce enhancement of coating system by substrate surface modification to allow atomic diffusion.

  13. Analysis of the Forces in Micromilling of Hardened AISI H13 Steel with Different Grain Sizes Using the Taguchi Methodology

    Directory of Open Access Journals (Sweden)

    Carlos Henrique Lauro

    2014-05-01

    Full Text Available The micromachining process has been applied to the free form and micromolds markets. This has occurred due to the growth in demand for microcomponents. However, micromachining of hardened steels is a challenge due to the reduction in tool life and the increase of the surface roughness when compared with the macromachining process. This paper focused on the analysis of micromilling forces on hardened AISI H13 steel with different grain sizes. Experimental tests were carried out on workpieces with different austenitic grain sizes and a hardness of 46 HRC. Micro-end-mill cutters with a diameter of 0.5 mm and (TiAlN coatings were applied in the milling of workpieces of 11 × 11 mm. The input parameters were two radial depths of cut, two cutting speeds, and two feed rates. The influence of the input parameters on the response cutting force was analyzed using the Taguchi method. Finally, considering the large grain size, the cutting forces in the x-, y-, and z-axes direction were small.

  14. Experimental investigation and modelling of surface roughness and resultant cutting force in hard turning of AISI H13 Steel

    Science.gov (United States)

    Boy, M.; Yaşar, N.; Çiftçi, İ.

    2016-11-01

    In recent years, turning of hardened steels has replaced grinding for finishing operations. This process is compared to grinding operations; hard turning has higher material removal rates, the possibility of greater process flexibility, lower equipment costs, and shorter setup time. CBN or ceramic cutting tools are widely used hard part machining. For successful application of hard turning, selection of suitable cutting parameters for a given cutting tool is an important step. For this purpose, an experimental investigation was conducted to determine the effects of cutting tool edge geometry, feed rate and cutting speed on surface roughness and resultant cutting force in hard turning of AISI H13 steel with ceramic cutting tools. Machining experiments were conducted in a CNC lathe based on Taguchi experimental design (L16) in different levels of cutting parameters. In the experiments, a Kistler 9257 B, three cutting force components (Fc, Ff and Fr) piezoelectric dynamometer was used to measure cutting forces. Surface roughness measurements were performed by using a Mahrsurf PS1 device. For statistical analysis, analysis of variance has been performed and mathematical model have been developed for surface roughness and resultant cutting forces. The analysis of variance results showed that the cutting edge geometry, cutting speed and feed rate were the most significant factors on resultant cutting force while the cutting edge geometry and feed rate were the most significant factor for the surface roughness. The regression analysis was applied to predict the outcomes of the experiment. The predicted values and measured values were very close to each other. Afterwards a confirmation tests were performed to make a comparison between the predicted results and the measured results. According to the confirmation test results, measured values are within the 95% confidence interval.

  15. The effects of annealing temperature and cooling rate on carbide precipitation behavior in H13 hot-work tool steel

    International Nuclear Information System (INIS)

    Kang, Minwoo; Park, Gyujin; Jung, Jae-Gil; Kim, Byung-Hoon; Lee, Young-Kook

    2015-01-01

    Highlights: • Unexpected Mo carbides formed during slow cooling from low annealing temperatures. • Mo carbides formed during the migration of Mo for a transition of Cr-rich carbide. • Mo carbides were precipitated at the boundaries of M 7 C 3 carbides and ferrite grains. • Annealing conditions for the precipitation of Mo carbides were discussed. - Abstract: The precipitation behavior of H13 hot-work tool steel was investigated as a function of both annealing temperature and cooling rate through thermodynamic calculations and microstructural analyses using transmission and scanning electron microscope and a dilatometer. The V-rich MC carbide and Cr-rich M 7 C 3 and M 23 C 6 carbides were observed in all annealed specimens regardless of annealing and cooling conditions, as expected from an equilibrium phase diagram of the steel used. However, Mo-rich M 2 C and M 6 C carbides were unexpectedly precipitated at a temperature between 675 °C and 700 °C during slow cooling at a rate of below 0.01 °C/s from the annealing temperatures of 830 °C and below. The solubility of Mo in both M 7 C 3 and ferrite reduces with decreasing temperature during cooling. Mo atoms diffuse out of both M 7 C 3 and ferrite, and accumulate locally at the interface between M 7 C 3 and ferrite. Mo carbides were form at the interface of M 7 C 3 carbides during the transition of Cr-rich M 7 C 3 to stable M 23 C 6

  16. Effect of Heat Treatment on Microstructure and Mechanical Properties of Laser Additively Manufactured AISI H13 Tool Steel

    Science.gov (United States)

    Chen, ChangJun; Yan, Kai; Qin, Lanlan; Zhang, Min; Wang, Xiaonan; Zou, Tao; Hu, Zengrong

    2017-11-01

    The effect of heat treatment on microstructure and mechanical properties (microhardness, wear resistance and impact toughness) of laser additively manufactured AISI H13 tool steel was systemically investigated. To understand the variation of microstructure and mechanical properties under different heat treatments, the as-deposited samples were treated at 350, 450, 550, 600 and 650 °C/2 h, respectively. Microstructure and phase transformation were investigated through optical microscopy, scanning electron microscope and transmission electron microscope. The mechanical properties were characterized by nanoindentation tests, Charpy tests and high-temperature wear tests. The microstructure of as-deposited samples consisted of martensite, ultrafine carbides and retained austenite. After the tempering treatment, the martensite was converted into tempered martensite and some fine alloy carbides which precipitated in the matrix. When treated at 550 °C, the greatest hardness and nanohardness were 600 HV0.3 and 6119.4 MPa due to many needle-like carbides precipitation. The value of hardness increased firstly and then decreased when increasing the temperature. When tempered temperatures exceeded 550 °C, the carbides became coarse, and martensitic matrix recrystallized at the temperature of 650 °C. The least impact energy was 6.0 J at a temperature of 550 °C. Samples tempered at 550 °C had larger wear volume loss than that of others. Wear resistances of all samples under atmospheric condition at 400 °C showed an oxidation mechanism.

  17. Investigation of plume dynamics during picosecond laser ablation of H13 steel using high-speed digital holography

    Science.gov (United States)

    Pangovski, Krste; Otanocha, Omonigho B.; Zhong, Shan; Sparkes, Martin; Liu, Zhu; O'Neill, William; Li, Lin

    2017-02-01

    Ablation of H13 tool steel using pulse packets with repetition rates of 400 and 1000 kHz and pulse energies of 75 and 44 μ {J}, respectively, is investigated. A drop in ablation efficiency (defined here as the depth per pulse or μ {m}{/}μ {J}) is shown to occur when using pulse energies of E_{{pulse}} > 44 μ {J}, accompanied by a marked difference in crater morphology. A pulsed digital holographic system is applied to image the resulting plumes, showing a persistent plume in both cases. Holographic data are used to calculate the plume absorption and subsequently the fraction of pulse energy arriving at the surface after traversing the plume for different pulse arrival times. A significant proportion of the pulse energy is shown to be absorbed in the plume for E_{{pulse}} > 44 μ {J} for pulse arrival times corresponding to {>}1 MHz pulse repetition rate, shifting the interaction to a vapour-dominated ablation regime, an energetically costlier ablation mechanism.

  18. Tool Wear and Formation Mechanism of White Layer When Hard Milling H13 Steel under Different Cooling/Lubrication Conditions

    Directory of Open Access Journals (Sweden)

    Song Zhang

    2014-04-01

    Full Text Available The present work aims at revealing the formation mechanism of white layer and understanding the effects of tool wear and cooling/lubrication condition on white layer when hard milling H13 steel with coated cutting tools. Hard milling experiments were carried out, and tool wear and its effect on formation of white layer were investigated. Compared to dry cutting condition, CMQL (cryogenic minimum quantity lubrication technique can obviously reduce tool wear and prolong tool life owing to its good cooling and lubrication properties. The optical images of the subsurface materials indicate that the formation of white layer is related to tool wear; moreover, the thickness of white layer increases with the increase of tool wear. SEM (scanning electron microscope images and XRD (X-ray diffraction analysis confirm that the formation of white layer is mainly due to the mechanical effect rather than the thermal effect. It also proves that white layer is partly decreased or can be totally eliminated by optimizing process parameters under CMQL cutting condition. CMQL technique has the potential to be used for achieving prolonged tool life and enhanced surface integrity.

  19. Influence of the nitriding and TiAlN/TiN coating thickness in the mechanical properties of a duplex treated H13 steel

    International Nuclear Information System (INIS)

    Torres, Ricardo D.; Soares, Paulo; Suzuki, Luciane Y.; Lepienski, Carlos M.

    2010-01-01

    AISI H13 die steel substrates were low pressure gas nitrided in three different nitriding cases. In the nitriding case A, the surface hardness was around 12 GPa and the nitriding thickness was around 40 μm. In the nitriding case B, the hardness was the same as in case A, but the nitriding thickness was around 70 μm. Finally, in the nitriding case C, the nitriding thickness was the same as in case B, but hardness profile showed a different behavior. In case C, the surface hardness was the same as case A and B. But the hardness increases as one move away from the surface showing the highest hardness at 15 "m from the sample surface. The XRD results showed that the nitriding cases microstructure is composed mainly by the diffusion layer with small amount of Cr_2N precipitates. These nitrided samples were subsequently coated with TiAlN using cathodic arc evaporation in two thicknesses of 3 and 7 μm. These samples were characterized with respect to phase chemistry, adhesion, hardness, elastic modulus and scratch tests. The phase chemistry determined through XRD revealed that coating was mostly Ti_0_._7Al_0_._3N with some peaks of TiN which comes from the adhesion layer that was deposited prior to the deposition of TiAlN. The instrumented hardness performed in the coated samples showed that the coating system hardness changes with the nitriding cases when the coating thickness is 3 μm. On the other hand, the nitriding characteristics do not influence the coating hardness with thickness of 7 μm. In addition, the 7 μm thick coating is harder than the 3 μm thick coating. In the last part of this work, TiAlN was deposited in the AISI H13 substrate without nitriding; it was found that the hardness in this condition is higher than the nitrided/coated samples. The worn area, probed by the scratch test, was smaller for the TiAlN deposited over AISI H13 without the nitriding layer. (author)

  20. Mechanism of generation of large (Ti,Nb,V)(C,N)-type precipitates in H13 + Nb tool steel

    Science.gov (United States)

    Xie, You; Cheng, Guo-guang; Chen, Lie; Zhang, Yan-dong; Yan, Qing-zhong

    2016-11-01

    The characteristics and generation mechanism of (Ti,Nb,V)(C,N) precipitates larger than 2 μm in Nb-containing H13 bar steel were studied. The results show that two types of (Ti,Nb,V)(C,N) phases exist—a Ti-V-rich one and an Nb-rich one—in the form of single or complex precipitates. The sizes of the single Ti-V-rich (Ti,Nb,V)(C,N) precipitates are mostly within 5 to 10 μm, whereas the sizes of the single Nb-rich precipitates are mostly 2-5 μm. The complex precipitates are larger and contain an inner Ti-V-rich layer and an outer Nb-rich layer. The compositional distribution of (Ti,Nb,V)(C,N) is concentrated. The average composition of the single Ti-V-rich phase is (Ti0.511V0.356Nb0.133)(C x N y ), whereas that for the single Nb-rich phase is (Ti0.061V0.263Nb0.676)(C x N y ). The calculation results based on the Scheil-Gulliver model in the Thermo-Calc software combining with the thermal stability experiments show that the large phases precipitate during the solidification process. With the development of solidification, the Ti-V-rich phase precipitates first and becomes homogeneous during the subsequent temperature reduction and heat treatment processes. The Nb-rich phase appears later.

  1. 激光熔覆TiC-H13涂层的微结构及耐腐蚀性能的研究%Study on Microstructure and Electrochemical Corrosion Resistance of Laser Cladding TiC-H13 Steel Composite Coating

    Institute of Scientific and Technical Information of China (English)

    杨倩; 黄宛真; 孔凡志

    2016-01-01

    TiC-H 13 cladding layer was produced by laser cladding on H 13 steel substrate.The effects of TiC on microstructure and electrochemical corrosion behavior of TiC-H13 layer were studied by SEM,EDS,TEM and anodic polarization curve.The results show that good metallurgical bonding is formed between the TiC-H 13 cladding layer and H 13 steel substrate.The new phase of TiC is formed in the laser cladding layer.Compared with H13 steel,the TiC-H13 cladding layer demonstrates much higher corrosion potential and the lower corrosion current,which exhibites significantly higher corrosion resistant.%以H13钢为基体,通过激光熔覆TiC-H13混合粉末获得熔覆层,考察TiC的加入对TiC-H13熔覆层的微观结构以及耐腐蚀性能的影响.采用SEM、EDS和TEM对熔覆层内的微观组成和物相进行表征,利用电化学阳极极化曲线研究熔覆层的耐腐蚀性能.结果表明:TiC-H13粉末和H13钢基体可以形成良好的熔覆层,熔覆层与基体紧密结合,熔覆层中形成新物相TiC.与H13钢相比,TiC-H 13熔覆层的腐蚀电位明显升高,腐蚀电流明显降低,耐腐蚀性能得到显著提高.

  2. Improvement of Tribological Performance of AISI H13 Steel by Means of a Self-Lubricated Oxide-Containing Tribo-layer

    Science.gov (United States)

    Cui, Xianghong; Jin, Yunxue; Chen, Wei; Zhang, Qiuyang; Wang, Shuqi

    2018-03-01

    A self-lubricated oxide-containing tribo-layer was induced to form by continuously adding particles of MoS2, Fe2O3 or their mixtures onto sliding interfaces of AISI H13 and 52100 steels. The artificial tribo-layer was always noticed to form continuously and cover the worn surface (termed as cover-type), whereas the original tribo-layer spontaneously formed with no additive was usually discontinuous and inserted into the substrate (termed as insert-type). Clearly, the cover-type and insert-type tribo-layers exactly corresponded to low and high wear rates, respectively. For the mixed additives of Fe2O3 + MoS2, the protective tribo-layers presented a load-carrying capability and lubricative function, which are attributed to the existence of Fe2O3 and MoS2. Hence, the wear rates and friction coefficients of H13 steel were markedly reduced.

  3. Effect of Energy Input on the Characteristic of AISI H13 and D2 Tool Steels Deposited by a Directed Energy Deposition Process

    Science.gov (United States)

    Park, Jun Seok; Park, Joo Hyun; Lee, Min-Gyu; Sung, Ji Hyun; Cha, Kyoung Je; Kim, Da Hye

    2016-05-01

    Among the many additive manufacturing technologies, the directed energy deposition (DED) process has attracted significant attention because of the application of metal products. Metal deposited by the DED process has different properties than wrought metal because of the rapid solidification rate, the high thermal gradient between the deposited metal and substrate, etc. Additionally, many operating parameters, such as laser power, beam diameter, traverse speed, and powder mass flow rate, must be considered since the characteristics of the deposited metal are affected by the operating parameters. In the present study, the effect of energy input on the characteristics of H13 and D2 steels deposited by a direct metal tooling process based on the DED process was investigated. In particular, we report that the hardness of the deposited H13 and D2 steels decreased with increasing energy input, which we discuss by considering microstructural observations and thermodynamics.

  4. Optimization of Minimum Quantity Lubricant Conditions and Cutting Parameters in Hard Milling of AISI H13 Steel

    OpenAIRE

    The-Vinh Do; Quang-Cherng Hsu

    2016-01-01

    As a successful solution applied to hard machining, the minimum quantity lubricant (MQL) has already been established as an alternative to flood coolant processing. The optimization of MQL parameters and cutting parameters under MQL condition are essential and pressing. The study was divided into two parts. In the first part of this study, the Taguchi method was applied to find the optimal values of MQL condition in the hard milling of AISI H13 with consideration of reduced surface roughness....

  5. Effects of Deep Cryogenic Treatment on the Wear Resistance and Mechanical Properties of AISI H13 Hot-Work Tool Steel

    Science.gov (United States)

    Çiçek, Adem; Kara, Fuat; Kıvak, Turgay; Ekici, Ergün; Uygur, İlyas

    2015-11-01

    In this study, a number of wear and tensile tests were performed to elucidate the effects of deep cryogenic treatment on the wear behavior and mechanical properties (hardness and tensile strength) of AISI H13 tool steel. In accordance with this purpose, three different heat treatments (conventional heat treatment (CHT), deep cryogenic treatment (DCT), and deep cryogenic treatment and tempering (DCTT)) were applied to tool steel samples. DCT and DCTT samples were held in nitrogen gas at -145 °C for 24 h. Wear tests were conducted on a dry pin-on-disk device using two loads of 60 and 80 N, two sliding velocities of 0.8 and 1 m/s, and a wear distance of 1000 m. All test results showed that DCT improved the adhesive wear resistance and mechanical properties of AISI H13 steel. The formation of small-sized and uniformly distributed carbide particles and the transformation of retained austenite to martensite played an important role in the improvements in the wear resistance and mechanical properties. After cleavage fracture, the surfaces of all samples were characterized by the cracking of primary carbides, while the DCT and DCTT samples displayed microvoid formation by decohesion of the fine carbides precipitated during the cryo-tempering process.

  6. Flank wears Simulation by using back propagation neural network when cutting hardened H-13 steel in CNC End Milling

    Science.gov (United States)

    Hazza, Muataz Hazza F. Al; Adesta, Erry Y. T.; Riza, Muhammad

    2013-12-01

    High speed milling has many advantages such as higher removal rate and high productivity. However, higher cutting speed increase the flank wear rate and thus reducing the cutting tool life. Therefore estimating and predicting the flank wear length in early stages reduces the risk of unaccepted tooling cost. This research presents a neural network model for predicting and simulating the flank wear in the CNC end milling process. A set of sparse experimental data for finish end milling on AISI H13 at hardness of 48 HRC have been conducted to measure the flank wear length. Then the measured data have been used to train the developed neural network model. Artificial neural network (ANN) was applied to predict the flank wear length. The neural network contains twenty hidden layer with feed forward back propagation hierarchical. The neural network has been designed with MATLAB Neural Network Toolbox. The results show a high correlation between the predicted and the observed flank wear which indicates the validity of the models.

  7. Flank wears Simulation by using back propagation neural network when cutting hardened H-13 steel in CNC End Milling

    International Nuclear Information System (INIS)

    Al Hazza, Muataz Hazza F; Adesta, Erry Y T; Riza, Muhammad

    2013-01-01

    High speed milling has many advantages such as higher removal rate and high productivity. However, higher cutting speed increase the flank wear rate and thus reducing the cutting tool life. Therefore estimating and predicting the flank wear length in early stages reduces the risk of unaccepted tooling cost. This research presents a neural network model for predicting and simulating the flank wear in the CNC end milling process. A set of sparse experimental data for finish end milling on AISI H13 at hardness of 48 HRC have been conducted to measure the flank wear length. Then the measured data have been used to train the developed neural network model. Artificial neural network (ANN) was applied to predict the flank wear length. The neural network contains twenty hidden layer with feed forward back propagation hierarchical. The neural network has been designed with MATLAB Neural Network Toolbox. The results show a high correlation between the predicted and the observed flank wear which indicates the validity of the models

  8. Electrochemical and wear behavior of niobium-vanadium carbide coatings produced on AISI H13 tool steel through thermo-reactive deposition/diffusion

    International Nuclear Information System (INIS)

    Castillejo Nieto, Fabio Enrique; Olaya Flores, Jhon Jairo; Alfonso Orjuela, Jose Edgar

    2016-01-01

    We deposited of niobium-vanadium carbide coatings on tool steel AISI H13 using the thermo-reactive substrates deposition/diffusion (TRD) technique. The carbides were obtained using salt baths composed of molten borax, ferroniobium, vanadium and aluminum, by heating this mixture at 1020°C for 4 hours. The coatings were characterized morphologically via electron microscopy scanning (SEM), the chemical surface composition was determined through X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX); the crystal structure was analyzed using x-ray diffraction (XRD), the mechanical properties of the coatings were evaluated using nano-indentation, The tribological properties of the coatings obtained were determined using a Pin-on-disk tribometer and the electrochemical behavior was studied through potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the hardness of the coated steel increased four times with respect to uncoated steel, and the electrochemical test established that the corrosion current is lower by one order of magnitude for coated steel

  9. Optimization of Minimum Quantity Lubricant Conditions and Cutting Parameters in Hard Milling of AISI H13 Steel

    Directory of Open Access Journals (Sweden)

    The-Vinh Do

    2016-03-01

    Full Text Available As a successful solution applied to hard machining, the minimum quantity lubricant (MQL has already been established as an alternative to flood coolant processing. The optimization of MQL parameters and cutting parameters under MQL condition are essential and pressing. The study was divided into two parts. In the first part of this study, the Taguchi method was applied to find the optimal values of MQL condition in the hard milling of AISI H13 with consideration of reduced surface roughness. The L9 orthogonal array, the signal-to-noise (S/N ratio and analysis of variance (ANOVA were employed to analyze the effect of the performance characteristics of MQL parameters (i.e., cutting fluid type, pressure, and fluid flow on good surface finish. In the results section, lubricant and pressure of MQL condition are determined to be the most influential factors which give a statistically significant effect on machined surfaces. A verifiable experiment was conducted to demonstrate the reliability of the results. In the second section, the optimized MQL parameters were applied in a series of experiments to find out cutting parameters of hard milling. The Taguchi method was also used to optimize the cutting parameters in order to obtain the best surface roughness. The design of the experiment (DOE was implemented by using the L27 orthogonal array. Based on an analysis of the signal-to-noise response and ANOVA, the optimal values of cutting parameters (i.e., cutting speed, feed rate, depth-of-cut and hardness of workpiece were introduced. The results of the present work indicate feed rate is the factor having the most effect on surface roughness.

  10. Medium carbon vanadium steels for closed die forging

    International Nuclear Information System (INIS)

    Jeszensky, Gabor; Plaut, Ronald Lesley

    1993-01-01

    This work analyses the medium carbon micro alloyed vanadium potential for closed die forged production. The steels reach the mechanical resistance requests during cooling after forging, eliminating the subsequent thermal treatment. Those steels also present good fatigue resistance and machinability. The industrial scale experiments are also reported

  11. Comparison of surface roughness and chip characteristics obtained under different modes of lubrication during hard turning of AISI H13 tool work steel.

    Science.gov (United States)

    Raj, Anil; Wins, K. Leo Dev; Varadarajan, A. S.

    2016-09-01

    Surface roughness is one of the important parameters, which not only affects the service life of a component but also serves as a good index of machinability. Near Dry Machining, methods (NDM) are considered as sustainable alternative for workshops trying to bring down their dependence on cutting fluids and the hazards associated with their indiscriminate usage. The present work presents a comparison of the surface roughness and chip characteristics during hard turning of AISI H13 tool work steel using hard metal inserts under two popular NDM techniques namely the minimal fluid application and the Minimum Quantity Lubrication technique(MQL) using an experiment designed based on Taguchi's techniques. The statistical method of analysis of variance (ANOVA) was used to determine the relative significance of input parameters consisting of cutting speed, feed and depth of cut on the attainable surface finish and the chip characteristics. It was observed that the performance during minimal fluid application was better than that during MQL application.

  12. An experimental analysis of process parameters to manufacture micro-channels in AISI H13 tempered steel by laser micro-milling

    Science.gov (United States)

    Teixidor, D.; Ferrer, I.; Ciurana, J.

    2012-04-01

    This paper reports the characterization of laser machining (milling) process to manufacture micro-channels in order to understand the incidence of process parameters on the final features. Selection of process operational parameters is highly critical for successful laser micromachining. A set of designed experiments is carried out in a pulsed Nd:YAG laser system using AISI H13 hardened tool steel as work material. Several micro-channels have been manufactured as micro-mold cavities varying parameters such as scanning speed (SS), pulse intensity (PI) and pulse frequency (PF). Results are obtained by evaluating the dimensions and the surface finish of the micro-channel. The dimensions and shape of the micro-channels produced with laser-micro-milling process exhibit variations. In general the use of low scanning speeds increases the quality of the feature in both surface finishing and dimensional.

  13. The Influence of Temperature on the Frictional Behavior of Duplex-Coated Die Steel Rubbing Against Forging Brass

    Science.gov (United States)

    Ebrahimzadeh, I.; Ashrafizadeh, F.

    2015-01-01

    Improvement of die life under hot forging of brass alloys is considered vital from both economical and technical points of view. One of the best methods for improving die life is duplex coatings. In this research, the influence of temperature on the tribological behavior of duplex-coated die steel rubbing against forging brass was investigated. The wear tests were performed on a pin-on-disk machine from room temperature to 700 °C; the pins were made in H13 hot work tool steel treated by plasma nitriding and by PVD coatings of TiN-TiAlN-CrAlN. The disks were machined from a two-phase brass alloy too. The results revealed that the friction coefficient of this tribosystem went through a maximum at 550 °C and decreased largely at 700 °C. Furthermore, the formation of Cr2O3 caused the reduction of friction coefficient at 700 °C. PVD coatings proved their wear resistance up to 550 °C, well above the working temperature of the brass forging dies.

  14. Kinetics of steel heavy ingot formation in dies of semicontinuous-casting machines

    International Nuclear Information System (INIS)

    Tsukerman, V.Ya.; Marchenko, I.K.

    1986-01-01

    Formation kinetics of round section ingot of up to 0.67 m in diameter was analyzed in dies of semicontinuous-casting machines on casting of the most usable assortment steels: medium-carbon low-alloyed and chromium-nickel stainless steels. It is established that solidification coefficient decreases in direct proportion to ingot diameter. Value of different-thickness ingot skin at die outlet is in direct proportion to a casted steel overheating temperature, ingot diameter and inversely proportional to the number and diameter of holes in a ladder nozzle and square root of ingot drawing rate

  15. Effect of Heat Treatment on the Microstructure and Mechanical Properties of Nitrogen-Alloyed High-Mn Austenitic Hot Work Die Steel

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2017-03-01

    Full Text Available In view of the requirements for mechanical properties and service life above 650 °C, a high-Mn austenitic hot work die steel, instead of traditional martensitic hot work die steel such as H13, was developed in the present study. The effect of heat treatment on the microstructure and mechanical properties of the newly developed work die steel was studied. The results show that the microstructure of the high-Mn as-cast electroslag remelting (ESR ingot is composed of γ-Fe, V(C,N, and Mo2C. V(C,N is an irregular multilateral strip or slice shape with severe angles. Most eutectic Mo2C carbides are lamellar fish-skeleton-like, except for a few that are rod-shaped. With increasing solid solution time and temperature, the increased hardness caused by solid solution strengthening exceeds the effect of decreased hardness caused by grain size growth, but this trend is reversed later. As a result, the hardness of specimens after various solid solution heat treatments increases first and then decreases. The optimal combination of hardness and austenitic grain size can be obtained by soaking for 2 h at 1170 °C. The maximum Rockwell hardness (HRC is 47.24 HRC, and the corresponding austenite average grain size is 58.4 μm. When the solid solution time is 3 h at 1230 °C, bimodality presented in the histogram of the austenite grain size as a result of further progress in secondary recrystallization. Compared with the single-stage aging, the maximum impact energy of the specimen after two-stage aging heat treatment was reached at 16.2 J and increased by 29.6%, while the hardness decreased by 1–2 HRC. After two-stage aging heat treatment, the hardness of steel reached the requirements of superior grade H13, and the maximum impact energy was 19.6% higher than that of superior grade H13, as specified in NADCA#207-2003.

  16. Study the effect of elevated dies temperature on aluminium and steel round deep drawing

    International Nuclear Information System (INIS)

    Lean, Yeong Wei; Azuddin, M.

    2016-01-01

    Round deep drawing operation can only be realized by expensive multi-step production processes. To reduce the cost of processes while expecting an acceptable result, round deep drawing can be done at elevated temperature. There are 3 common problems which are fracture, wrinkling and earing of deep drawing a round cup. The main objective is to investigate the effect of dies temperature on aluminium and steel round deep drawing; with a sub-objective of eliminate fracture and reducing wrinkling effect. Experimental method is conducted with 3 different techniques on heating the die. The techniques are heating both upper and lower dies, heating only the upper dies, and heating only the lower dies. 4 different temperatures has been chosen throughout the experiment. The experimental result then will be compared with finite element analysis software. There is a positive result from steel material on heating both upper and lower dies, where the simulation result shows comparable as experimental result. Heating both upper and lower dies will be the best among 3 types of heating techniques. (paper)

  17. Production of High Quality Die Steels from Large ESR Slab Ingots

    Science.gov (United States)

    Geng, Xin; Jiang, Zhou-hua; Li, Hua-bing; Liu, Fu-bin; Li, Xing

    With the rapid development of manufacture industry in China, die steels are in great need of large slab ingot of high quality and large tonnage, such as P20, WSM718R and so on. Solidification structure and size of large slab ingots produced with conventional methods are not satisfied. However, large slab ingots manufactured by ESR process have a good solidification structure and enough section size. In the present research, the new slab ESR process was used to produce the die steels large slab ingots with the maximum size of 980×2000×3200mm. The compact and sound ingot can be manufactured by the slab ESR process. The ultra-heavy plates with the maximum thickness of 410 mm can be obtained after rolling the 49 tons ingots. Due to reducing the cogging and forging process, the ESR for large slab ingots process can increase greatly the yield and production efficiency, and evidently cut off product costs.

  18. Effect of Heat Treatment on the Structure and Properties of Die Steel 70Kh3G2FTR

    Science.gov (United States)

    Krylova, S. E.; Kletsova, O. A.; Gryzunov, V. I.; Fot, A. P.; Tavtilov, I. Sh.

    2018-01-01

    The effect of heat treatment parameters on the properties and structural and phase composition of a promising die steel 70Kh3G2FTR for hot deformation is studied. The temperature-and-stress state of a hammer die under a heat treatment is simulated.

  19. Medium carbon vanadium steels for closed die forging; Acos de medio carbono microligados ao vanadio para forjaria em matriz fechada

    Energy Technology Data Exchange (ETDEWEB)

    Jeszensky, Gabor; Plaut, Ronald Lesley

    1994-12-31

    This work analyses the medium carbon micro alloyed vanadium potential for closed die forged production. The steels reach the mechanical resistance requests during cooling after forging, eliminating the subsequent thermal treatment. Those steels also present good fatigue resistance and machinability. The industrial scale experiments are also reported 16 refs., 21 figs.

  20. Research on Oxidation Wear Behavior of a New Hot Forging Die Steel

    Science.gov (United States)

    Shi, Yuanji; Wu, Xiaochun

    2018-01-01

    Dry sliding tests for the hot forging die steel DM were performed in air under the test temperature at 400-700 °C and the time of 0.5-4 h by a UMT-3 high-temperature wear tester. The wear behavior and characteristics were studied systematically to explore the general characters in severe oxidation conditions. The results showed that a mild-to-severe oxidation wear transition occurred with an increase in the test temperature and duration. The reason was clarified as the unstable M6C carbides coarsening should be responsible for the severe delamination of tribo-oxide layer. More importantly, an intense oxidation wear with lower wear rates was found when the experimental temperature reaches 700 °C or after 4 h of test time at 600 °C, which was closely related to the degradation behavior during wear test. Furthermore, a new schematic diagram of oxidation wear of DM steel was proposed.

  1. Structural materialization of stainless steel molds and dies by the low temperature high density plasma nitriding

    Directory of Open Access Journals (Sweden)

    Aizawa Tatsuhiko

    2015-01-01

    Full Text Available Various kinds of stainless steels have been widely utilized as a mold substrate material for injection molding and as a die for mold-stamping and direct stamping processes. Since they suffered from high temperature transients and thermal cycles in practice, they must be surface-treated by dry and wet coatings, or, by plasma nitriding. Martensitic stainless steel mold was first wet plated by the nickel phosphate (NiP, which was unstable at the high temperature stamping condition; and, was easy to crystalize or to fracture by itself. This issue of nuisance significantly lowered the productivity in fabrication of optical elements at present. In the present paper, the stainless steel mold was surface-treated by the low-temperature plasma nitriding. The nitrided layer by this surface modification had higher nitrogen solute content than 4 mass%; the maximum solid-solubility of nitrogen is usually 0.1 mass% in the equilibrium phase diagram. Owing to this solid-solution with high nitrogen concentration, the nitrided layer had high hardness of 1400 Hv within its thickness of 40 μm without any formation of nitrides after 14.4 ks plasma nitriding at 693 K. This nitrogen solid-solution treated stainless steel had thermal resistivity even at the mold-stamping conditions up to 900 K.

  2. Finite element modelling of chain-die forming for ultra-high strength steel

    Science.gov (United States)

    Majji, Raju; Xiang, Yang; Ding, Scott; Yang, Chunhui

    2017-10-01

    There has been a high demand for weight reduction in automotive vehicles while maintaining passenger safety. A potential steel material to achieve this is Ultra High Strength Steel (UHSS). As a high strength material, it is difficult to be formed with desired profiles using traditional sheet metal forming processes such as Cold Roll Forming. To overcome this problem, a potentially alternative solution is Chain-die Forming (CDF), recently developed. The basic principal of the CDF is to fully combine roll forming and bending processes. The main advantage of this process is the elongated deformation length that significantly increases effective roll radius. This study focuses on identifying issues with the CDF by using CAD modelling, Motion Analysis and Finite Element Analysis (FEA) to devise solutions and construct a more reliable process in an optimal design sense. Some attempts on finite element modelling and simulation of the CDF were conducted using relatively simple models in literature and the research was still not sufficient enough for optimal design of a typical CDF for UHSS. Therefore two numerical models of Chain-die Forming process are developed in this study, including a) one having a set of rolls similar to roll forming but with a large radius, i.e., 20 meters; and b) the other one with dies and punch segments similar to a typical CDF machine. As a case study, to form a 60° channel with single pass was conducted using these two devised models for a comparison. The obtained numerical results clearly show the CDF could generate less residual stress, low strain and small springback of a single pass for the 60° UHSS channel. The design analysis procedure proposed in this study could greatly help the mechanical designers to devise a cost-effective and reliable CDF process for forming UHSS.

  3. Preliminary heat treatment of 4KhM2Fch die steel

    International Nuclear Information System (INIS)

    Leonidov, V.M.; Berezkin, Y.A.; Nikitenko, E.V.

    1986-01-01

    To improve the machinability and preparation of the structure for hardening, die steels are given a preliminary treatment which provides a reduction in hardness as a result of separation in the structure of the carbide and ferrite phases, coagulation of the carbides, and acquisition by them of a granular form and also the obtaining of fine grains and a uniform distribution of the structural constituents. The microstructure was evaluated after etching in 4% nital on an MIM-8M microscope. The 4KhM2Fch steel was given a preliminary heat treatment of normalize and anneal. It was concluded that for 4KhM2Fch steel a preliminary heat treatment of normalizing from 950 0 C with a hold of 1.5-2 h, annealing at 750-760 0 C with a hold of 2-3 h, cooling to the isothermal temperature of 670-680 0 C with a hold of 3-4 h, and further air cooling is recommended. The structure after such a heat is granular pearlite with a rating 1-2 and a hardness of 220-250 HB

  4. Effect of Contact Time on Interface Reaction between Aluminum Silicon (7% and 11% Alloy and Steel Dies SKD 61

    Directory of Open Access Journals (Sweden)

    Bambang Suharno

    2010-10-01

    Full Text Available Die soldering (die sticking is a defect of metal casting in which molten metal “welds” to the metallic die mold surface during casting process. Die soldering is the result of an interface reaction between the molten aluminum and the die material. Aluminum alloy with 7 and 11% silicon and SKD 61 die steel are the most common melt and die material used in aluminum die casting. This research is done to study the morphology and the characteristics of the formed AlxFeySiz intermetallic layer during interface reaction at dipping test. The samples of as-anneal SKD 61 tool steel was dipped into the molten of Al-7%Si held at temperature 680oC and into molten Al-11%Si held at temperature 710oC with the different contact time of 10 minutes; 30 minutes; and 50 minutes. The research results showed that the interface reaction can form a compact intermetallic layer with AlxFey phase and a broken intermetallic layer with AlxFeySiz phase on the surface of SKD 61 tool steel. The increasing of the contact time by the immersion of material SKD 61 tool steel in both of molten Al-7%Si and Al-11%Si will increase the thickness of the AlxFeySiz intermetallic layer until an optimum point and then decreasing. The micro hardness of the AlxFeySiz intermetallic layer depends on the content of the iron. Increasing of the iron content in intermetallic layer will increase the micro hardness of the AlxFeySiz. This condition happened because the increasing of Fe content will cause forming of intermetallic AlxFeySiz phase becomes quicker.

  5. An Experiment Study on Surface Roughness in High Speed Milling NAK80 Die Steel

    Directory of Open Access Journals (Sweden)

    Su Fa

    2016-01-01

    Full Text Available The paper introduces that the high speed milling experiments on NAK80 die steel was carried out on the DMU 60 mono BLOCK five axis linkage high speed CNC machining center tool by the TiAlN coated tools, in order to research the effect of milling parameters on surface roughness Ra. The results showed that the Ra value increased with the decrease of milling speed vc, increased with the axial depth of milling ap, and feed per tooth fz and radial depth of milling ae. On the basis of the single factor experiment results, the mathematics model for between surface roughness and milling parameters were established by linear regression analysis.

  6. The Analysis of Force Parameters in Drawing Process of High Carbon Steel Wires in Conventional and Hydrodynamic Dies

    Directory of Open Access Journals (Sweden)

    Suliga M.

    2017-12-01

    Full Text Available The paper analyzes force parameters in the process of multistage drawing of steel wires in conventional and hydrodynamic dies. The drawing process of the wire rod with a diameter of 5.5 mm for wires with a diameter of 1.70 mm was performed in 12 drafts with the usage of the multistage drawbench Koch KGT with the speed range of 5-25 m/s.

  7. Effect of triangular texture on the tribological performance of die steel with TiN coatings under lubricated sliding condition

    Science.gov (United States)

    Chen, Ping; Xiang, Xin; Shao, Tianmin; La, Yingqian; Li, Junling

    2016-12-01

    The friction and wear of stamping die surface can affect the service life of stamping die and the quality of stamping products. Surface texturing and surface coating have been widely used to improve the tribological performance of mechanical components. This study experimentally investigated the effect of triangular surface texture on the friction and wear properties of the die steel substrate with TiN coatings under oil lubrication. TiN coatings were deposited on a die steel (50Cr) substrate through a multi-arc ion deposition system, and then triangular surface texturing was fabricated by a laser surface texturing. The friction and wear test was conducted by a UMT-3 pin-on-disk tribometer under different sliding speeds and different applied loads, respectively. The adhesion test was performed to evaluate the effectiveness of triangular texturing on the interfacial bonding strength between the TiN coating and the die steel substrate. Results show that the combination method of surface texturing process and surface coating process has excellent tribological properties (the lowest frictional coefficient and wear volume), compared with the single texturing process or the single coating process. The tribological performance is improved resulting from the high hardness and low elastic modulus of TiN coatings, and the generation of hydrodynamic pressure, function of micro-trap for wear debris and micro-reservoirs for lubricating oil of the triangular surface texture. In addition, the coating bonding strength of the texturing sample is 3.63 MPa, higher than that of the single coating sample (3.48 MPa), but the mechanisms remain to be further researched.

  8. Formability of dual-phase steels in deep drawing of rectangular parts: Influence of blank thickness and die radius

    Science.gov (United States)

    López, Ana María Camacho; Regueras, José María Gutiérrez

    2017-10-01

    The new goals of automotive industry related with environment concerns, the reduction of fuel emissions and the security requirements have driven up to new designs which main objective is reducing weight. It can be achieved through new materials such as nano-structured materials, fibre-reinforced composites or steels with higher strength, among others. Into the last group, the Advance High Strength Steels (AHSS) and particularly, dual-phase steels are in a predominant situation. However, despite of their special characteristics, they present issues related to their manufacturability such as springback, splits and cracks, among others. This work is focused on the deep drawing processof rectangular shapes, a very usual forming operation that allows manufacturing several automotive parts like oil pans, cases, etc. Two of the main parameters in this process which affect directly to the characteristics of final product are blank thickness (t) and die radius (Rd). Influence of t and Rd on the formability of dual-phase steels has been analysed considering values typically used in industrial manufacturing for a wide range of dual-phase steels using finite element modelling and simulation; concretely, the influence of these parameters in the percentage of thickness reduction pt(%), a quite important value for manufactured parts by deep drawing operations, which affects to its integrity and its service behaviour. Modified Morh Coulomb criteria (MMC) has been used in order to obtain Fracture Forming Limit Diagrams (FFLD) which take into account an important failure mode in dual-phase steels: shear fracture. Finally, a relation between thickness reduction percentage and studied parameters has been established fordual-phase steels, obtaining a collection of equations based on Design of Experiments (D.O.E) technique, which can be useful in order to predict approximate results.

  9. Thermal Fatigue of Die-Casting Dies: An Overview

    Directory of Open Access Journals (Sweden)

    Abdulhadi Hassan A.

    2016-01-01

    Full Text Available Coupled studies by experimental and numerical simulations are necessary for an increased understanding of the material behaviour as related to the interaction between the thermal and mechanical conditions. This paper focus on the mechanisms of thermal fatigue in the failure of dies and cores used in the die casting of aluminum alloys. The thermal fatigue resistance is expressed by two crack parameters which are the average maximum crack and the average cracked area. Samples of various types of H13 steel were compared with a standard H13 steel by testing under identical thermal fatigue cycles. To determine the thermal constraint developed in the sample during the test, a finite difference technique was used to obtain the temperature distribution, based on temperature measurements at the boundaries. The resulting stresses and strains were computed, and the strain calculated at the edge or weakest point of the sample was used to correlate the number of cycles to crack initiation. As the strain at the edge increased, the number of cycles to failure decreased. The influence of various factors on thermal fatigue behavior was studied including austenitizing temperature, surface condition, stress relieving, casting, vacuum melting, and resulfurization. The thermal fatigue resistance improved as the austenitizing temperature increased from 1750 to 2050ºF.

  10. Experimental studies on improving the performance of electrochemical machining of high carbon, high chromium die steel using jet patterns

    Directory of Open Access Journals (Sweden)

    V. Sathiyamoorthy

    2014-03-01

    Full Text Available Electrochemical machining (ECM is a non-traditional process used mainly to cut hard or difficult-to-cut metals, where the application of a more traditional process is not convenient. Stiff market competition and ever-growing demand for better, durable and reliable products has brought about a material revolution, which has greatly expanded the families of difficult-to-machine materials namely highcarbon,high-chromium die steel; stainless steel and superalloys. This investigation attempts to analyze the effect of electrolyte distribution on material removal rate (MRR and surface roughness (SR on electrochemical machining of high-carbon, high-chromium die steel using NaCl aqueous solution. Three electrolyte jet patterns namely straight jet in circular, inclined jet in circular and straight jet in spiral were used for this experimentation. The results reveal that electrolyte distribution significantly improves the performance of ECM and the straight jet in spiral pattern performs satisfactorily in obtaining better MRR and surface roughness.

  11. Interlocking multi-material components made of structured steel sheets and high-pressure die cast aluminium

    Science.gov (United States)

    Senge, S.; Brachmann, J.; Hirt, G.; Bührig-Polaczek, A.

    2017-10-01

    Lightweight design is a major driving force of innovation, especially in the automotive industry. Using hybrid components made of two or more different materials is one approach to reduce the vehicles weight and decrease fuel consumption. As a possible way to increase the stiffness of multi-material components, this paper presents a process chain to produce such components made of steel sheets and high-pressure die cast aluminium. Prior to the casting sequence the steel sheets are structured in a modified rolling process which enables continuous interlocking with the aluminium. Two structures manufactured by this rolling process are tested. The first one is a channel like structure and the second one is a channel like structure with undercuts. These undercuts enable the formation of small anchors when the molten aluminium fills them. The correlation between thickness reduction during rolling and the shape of the resulting structure was evaluated for both structures. It can be stated that channels with a depth of up to 0.5 mm and a width of 1 mm could be created. Undercuts with different size depending on the thickness reduction could be realised. Subsequent aluminium high-pressure die casting experiments were performed to determine if the surface structure can be filled gap-free with molten aluminium during the casting sequence and if a gap-free connection can be achieved after contraction of the aluminium. The casting experiments showed that both structures could be filled during the high-pressure die casting. The channel like structure results in a gap between steel and aluminium after contraction of the cast metal whereas the structure with undercuts leads to a good interlocking resulting in a gap-free connection.

  12. Economical surface treatment of die casting dies to prevent soldering in high pressure casting

    International Nuclear Information System (INIS)

    Fraser, D.T.; Jahedi, M.Z.

    2001-01-01

    This paper describes the use of a gas oxidation treatment of H13 tool steel to develop a compact iron oxide layer at the surface of core pins to prevent soldering in high pressure die casting. The performance of oxide layers in the protection of die steel against soldering during high pressure die casting was tested in a specially designed die using removable core pins and Al-11 Si-3 Cu casting alloy. The gas oxidation treatment can be applied at low temperatures and to large areas of the die surface. In addition this process is very cost effective compared to other coating processes such as physical vapour deposition (PVD), or thermo-reactive diffusion (TRD) coatings. This work demonstrated that surface treatment producing pure magnetite (Fe 3 O 4 ) layers are more protective than oxide layers containing a combination of Fe 3 O 4 (magnetite) and Fe 3 O 3 (haematite). The magnetite layer acts as a barrier between the die steel/casting alloy interface and prevents the formation of inter-metallic phases. Optical microscopy and scanning electron microscope were used to determine the thickness of the oxide layer, while X-ray diffraction was performed to determine the oxide phase structure

  13. Morphology and Performance of 5Cr5MoV Casting Die Steel in the Process of Surfacing

    Science.gov (United States)

    Song, Yulai; Kong, Xiangrui; Yang, Pengcong; Fu, Hongde; Wang, Xuezhu

    2017-12-01

    To investigate the microstructures and mechanical properties of the deposited metal on surface of die steel, two layer of weld-seam were prepared on the surface of 5Cr5MoV die steel by arc surfacing. The surface microstructures and microhardness were characterized by scanning electron microscopy, energy dispersive spectrometer and Vickers microhardness tester, respectively. The effect of load on the abrasion resistance and wear mechanism of the base metal and surfacing metal was studied by pin-on-disk tribometer. The results showed that martensite and retained austenite exist in weld-seam, both of them grow up in the form of dendrites and equiaxed grains and microhardness reach 774.2HV. The microstructures of the quenching zone mainly consist of martensite and retained austenite, while tempered martensite is the dominant phase in partial quenching zone. The abrasion resistance of the surfacing metal is superior to the base metal based on the results of wear test. The wear rates of surfacing metal and base metal raise with the increase of load. The wear rates of base metal raise extremely when the load reach 210N. Both of two kinds of materials have the similar wear mechanism, namely, abrasive wear at low load, oxidative wear and adhesive wear at high load.

  14. Multi-field coupling finite element analysis for determining the influence of temperature field on die service life during precision-forming process of steel synchronizer ring

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jun; Luo, Shan-Ming; Li, Feng-Qiang; Xu, Chen-Bing [Xiamen University of Technology, Xiamen (China)

    2017-07-15

    Failure analysis shows that increased die temperature caused by severe plastic deformation of material and heat conduction between hot billet and cavity significantly affects the distortion of gear cavity in steel synchronizer ring forging process. The forging process of steel synchronizer ring and die temperature distribution under different forging conditions are analyzed through finite element method. Simulation results show that severe plastic deformation occurs in the gear cavity. The improvement of lubrication condition results in decreased die temperature. When the initial billet temperature is high, the die temperature is also high. Increasing forging speed in a certain range facilitates the die temperature decrease. The distribution of die temperature in synthetic forming technology is more reasonable than that of one step forging. The synthetic forming technology is adopted in production to reduce the effects of severe plastic deformation caused by die temperature. The ejection mechanism and control system of the double disc friction press are improved to reduce the contact time between the hot billet and cavity. Experimental results show that synthetic forming technology is reasonable, and that the die service life is prolonged.

  15. Multi-field coupling finite element analysis for determining the influence of temperature field on die service life during precision-forming process of steel synchronizer ring

    International Nuclear Information System (INIS)

    Zhao, Jun; Luo, Shan-Ming; Li, Feng-Qiang; Xu, Chen-Bing

    2017-01-01

    Failure analysis shows that increased die temperature caused by severe plastic deformation of material and heat conduction between hot billet and cavity significantly affects the distortion of gear cavity in steel synchronizer ring forging process. The forging process of steel synchronizer ring and die temperature distribution under different forging conditions are analyzed through finite element method. Simulation results show that severe plastic deformation occurs in the gear cavity. The improvement of lubrication condition results in decreased die temperature. When the initial billet temperature is high, the die temperature is also high. Increasing forging speed in a certain range facilitates the die temperature decrease. The distribution of die temperature in synthetic forming technology is more reasonable than that of one step forging. The synthetic forming technology is adopted in production to reduce the effects of severe plastic deformation caused by die temperature. The ejection mechanism and control system of the double disc friction press are improved to reduce the contact time between the hot billet and cavity. Experimental results show that synthetic forming technology is reasonable, and that the die service life is prolonged.

  16. Plastohydrodynamic drawing and coating of stainless steel wire using a tapered bore die of no metal to metal contact

    Science.gov (United States)

    Hasan, S.; Basmage, O.; Stokes, J. T.; Hashmi, M. S. J.

    2018-05-01

    A review of wire coating studies using plasto-hydrodynamic pressure shows that most of the works were carried out by conducting experiments simultaneously with simulation analysis based upon Bernoulli's principle and Euler and Navier-Stokes (N-S) equations. These characteristics relate to the domain of Computational Fluid Dynamics (CFD) which is an interdisciplinary topic (Fluid Mechanics, Numerical Analysis of Fluid flow and Computer Science). This research investigates two aspects: (i) simulation work and (ii) experimentation. A mathematical model was developed to investigate the flow pattern of the molten polymer and pressure distribution within the wire-drawing dies, assessment of polymer coating thickness on the coated wires and speed of coating on the wires at the outlet of the drawing dies, without deploying any pressurizing pump. In addition to a physical model which was developed within ANSYS™ environment through the simulation design of ANSYS™ Workbench. The design was customized to simulate the process of wire-coating on the fine stainless-steel wires using drawing dies having different bore geometries such as: stepped parallel bore, tapered bore and combined parallel and tapered bore. The convergence of the designed CFD model and numerical and physical solution parameters for simulation were dynamically monitored for the viscous flow of the polypropylene (PP) polymer. Simulation results were validated against experimental results and used to predict the ideal bore shape to produce a thin coating on stainless wires with different diameter. Simulation studies confirmed that a specific speed should be attained by the stainless-steel wires while passing through the drawing dies. It has been observed that all the speed values within specific speed range did not produce a coating thickness having the desired coating characteristic features. Therefore, some optimization of the experimental set up through design of experiments (Stat-Ease) was applied to

  17. Effect of Various Heat Treatment Processes on Fatigue Behavior of Tool Steel for Cold Forging Die

    Science.gov (United States)

    Jin, S. U.; Kim, S. S.; Lee, Y. S.; Kwon, Y. N.; Lee, J. H.

    Effects of various heat treatment processes, including "Q/T (quenching and tempering)", "Q/CT/T (Quenching, cryogenic treatment and tempering)", "Q/T (quenching and tempering) + Ti-nitriding" and "Q/CT/T (Cryogenic treatment and tempering) + Ti-nitriding", on S-N fatigue behavior of AISI D2 tool steel were investigated. The optical micrographs and Vicker's hardness values at near surface and core area were examined for each specimen. Uniaxial fatigue tests were performed by using an electro-magnetic resonance fatigue testing machine at a frequency of 80 Hz and an R ratio of -1. The overall resistance to fatigue tends to decrease significantly with Ti-nitriding treatment compared to those for the general Q/T and Q/CT/T specimens. The reduced resistance to fatigue with Ti-nitriding is discussed based on the microstructural and fractographic analyses.

  18. Effects of mechanical strain amplitude on the isothermal fatigue behavior of H13

    Science.gov (United States)

    Zeng, Yan; Zuo, Peng-peng; Wu, Xiao-chun; Xia, Shu-wen

    2017-09-01

    Isothermal fatigue (IF) tests were performed on H13 tool steel subjected to three different mechanical strain amplitudes at a constant temperature to determine the effects of mechanical strain amplitude on the microstructure of the steel samples. The samples' extent of damage after IF tests was compared by observation of their cracks and calculation of their damage parameters. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to observe the microstructure of the samples. Cracks were observed to initiate at the surface because the strains and stresses there were the largest during thermal cycling. Mechanical strain accelerated the damage and softening of the steel. A larger mechanical strain caused greater deformation of the steel, which made the precipitated carbides easier to gather and grow along the deformation direction, possibly resulting in softening of the material or the initiation of cracks.

  19. Surface quality analysis of die steels in powder-mixed electrical discharge machining using titan powder in fine machining

    Directory of Open Access Journals (Sweden)

    Banh Tien Long

    2016-06-01

    Full Text Available Improving the quality of surface molds after electrical discharge machining is still being considered by many researchers. Powder-mixed dielectric in electrical discharge machining showed that it is one of the processing methods with high efficiency. This article reports on the results of surface quality of mold steels after powder-mixed electrical discharge machining using titanium powder in fine machining. The process parameters such as electrode material, workpiece material, electrode polarity, pulse on-time, pulse off-time, current, and titanium powder concentration were considered in the research. These materials are most commonly used with die-sinking electrical discharge machining in the manufacture of molds and has been selected as the subject of research: workpiece materials were SKD61, SKT4, and SKD11 mold steels, and electrode materials were copper and graphite. Taguchi’s method is used to design experiments. The influence of the parameters on surface roughness was evaluated through the average value and ratio (S/N. Results showed that the parameters such as electrical current, electrode material, pulse on-time, electrode polarity, and interaction between the electrode materials with concentration powder mostly influence surface roughness and surface roughness at optimal parameters SRopt = 1.73 ± 0.39 µm. Analysis of the surface layer after powder-mixed electrical discharge machining using titanium powder in optimal conditions has shown that the white layer with more uniform thickness and increased hardness (≈861.0 HV, and amount and size of microscopic cracks, is reduced. This significantly leads to the increase in the quality of the surface layer.

  20. Study on the Surface Microstructure of a Modified STD61 Steel Mold Used for the Die Casting Process

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ha-Young; Lee, Seung-Joon; Kang, Minwoo; Lee, Suk-Jin; Lee, Young-Kook [Yonsei University, Seoul (Korea, Republic of); Yang, Won Jon [Korea Institute of Materials Science, Changwon (Korea, Republic of); Jeong, Jae Suk; Kim, Byung-Hoon [Doosan Heavy Industries and Construction, Changwon (Korea, Republic of)

    2016-09-15

    The surface microstructure and crack formation of an aluminum die-casting mold were investigated. The mold was made of a modified STD61 steel, and was used for more than 165,000 cycles. The mold surface consisted of four layers; an oxidized layer, a decarburized layer, a network carbide layer and a tempered martensite matrix. The depth down to the hardest network carbide layer was ⁓200 μm. Inside the matrix, M{sub 3}C transition carbides were dissolved so that solute C joined pre-existing M{sub 2}3C{sub 6} and MC carbides to make them coarse. About 60% of thermal fatigue cracks had a depth less than 200 μm due to the hard network carbide layer, which obstructed the propagation of cracks. Cracks of over 200 μm were filled with oxide wedges of Al and Si which was which flown from the molten alloy as well as the Fe oxide.

  1. Die casting copper motor rotors: mold materials and processing for cost-effective manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Peters, D.T.; Cowie, J.G.; Brush, E.F. Jr.

    2000-07-01

    This project seeks to demonstrate mold materials for copper pressure die-casting that are cost-effective and practical for production use in die-casting copper motor rotors. The incorporation of die-cast copper for conductor bars and end rings of the induction motor in place of aluminum would result in attractive improvements in motor energy efficiency through reductions in motor losses ranging from 15% to 20%. Die-cast motor rotors are produced in aluminum today because rotor fabrication by pressure die-casting is an established practice. Lack of a durable and cost-effective mold material has been the technical barrier preventing manufacture of the die-cast copper rotor. This project tested H-13 steel die inserts that establish the baseline. Nickel-, tungsten-, and molybdenum-based high temperature alloys were extensively tested. Results indicate that substantially extended die life is possible using high temperature die materials, pre-heated and operated at elevated temperatures. Pre-heating and high operating temperatures were shown to be critical in extending the die life by decreasing the cyclic stresses associated with thermal expansion. Extended die life provides the opportunity for economically viable copper motor rotor die-casting. (orig.)

  2. Evaluation of interlocking bond strength between structured 1.0338 steel sheets and high pressure die cast AlMg5Si2

    Science.gov (United States)

    Senge, S.; Brachmann, J.; Hirt, G.; Bührig-Polaczek, A.

    2018-05-01

    Multi-material components open up new possibilities for functional design. Such components combine beneficial physical properties of different materials in a single component as for instance chemical resistance, high strength or low density. The challenge is a reliable bond between both materials to enable a long term usage. This paper deals with a form closure connection to ensure a solid connection between steel strips and high pressure die cast aluminium. Two different sizes of channel structures with width ratios of 1.0 and 1.35 are produced on a steel sheet. An ensuing flat rolling pass is performed to create undercuts with a width of up to 50 µm, enabling an interlocking of the molten aluminium in the concluding casting process. For both rolling processes the resulting geometry is analysed depending on the thickness reduction. In a subsequent high pressure die casting process, aluminium is applied resulting in a complete form filling for the coarser structure. Comparing structures with and without undercuts, only structures suited with undercuts remain gap-free after solidification contraction. The finer structure could not be filled completely; nevertheless these structures result in shear strength of up to 45 MPa transversal to the channel-direction.

  3. Steel

    International Nuclear Information System (INIS)

    Zorev, N.N.; Astafiev, A.A.; Loboda, A.S.; Savukov, V.P.; Runov, A.E.; Belov, V.A.; Sobolev, J.V.; Sobolev, V.V.; Pavlov, N.M.; Paton, B.E.

    1977-01-01

    Steels also containing Al, N and arsenic, are suitable for the construction of large components for high-power nuclear reactors due to their good mechanical properties such as good through-hardening, sufficiently low brittleness conversion temperature and slight displacement of the latter with neutron irradiation. Defined steels and their properties are described. (IHOE) [de

  4. die rol van die unieverdedigingsmag in die onderdrukking van die

    African Journals Online (AJOL)

    agv regeringsoptrede nie.39. Siotsom. In die geskiedenis van die Unieverdedigings- mag word die gebeure random die 1914-staking oorskadu deur die Rebellie en Suid-Afrika se deelname aan die Eerste Wereldoorlog. Tog was dit 'n belangrike mylpaal in die geskiedenis van die organisasie, omdat dit sy eerste optrede ...

  5. Structure of a Wear-Resistant Medium-Carbon Steel After Hot Deformation in Hammer Dies and Heat Treatment

    Science.gov (United States)

    Knyazyuk, T. V.; Petrov, S. N.; Ryabov, V. V.; Khlusova, E. I.

    2018-01-01

    The structure of model specimens and articles fabricated from medium-carbon high-strength steels is studied for developing modes of forming of working members of tilling machines with cutting edges thinned without the expensive operation of electromachining. The effect of the temperature of heating of billets on the grain size of austenite is determined. The kinetics of recrystallization is studied in the temperature, rate and strain ranges typical for hot forming. A quantitative crystallographic analysis of the microstructure is performed by the EBSD technique. The degrees of distortion of the crystal lattices of structural components and the mean sizes of martensite blocks are determined.

  6. Harmony search optimization in dimensional accuracy of die sinking EDM process using SS316L stainless steel

    Science.gov (United States)

    Deris, A. M.; Zain, A. M.; Sallehuddin, R.; Sharif, S.

    2017-09-01

    Electric discharge machine (EDM) is one of the widely used nonconventional machining processes for hard and difficult to machine materials. Due to the large number of machining parameters in EDM and its complicated structural, the selection of the optimal solution of machining parameters for obtaining minimum machining performance is remain as a challenging task to the researchers. This paper proposed experimental investigation and optimization of machining parameters for EDM process on stainless steel 316L work piece using Harmony Search (HS) algorithm. The mathematical model was developed based on regression approach with four input parameters which are pulse on time, peak current, servo voltage and servo speed to the output response which is dimensional accuracy (DA). The optimal result of HS approach was compared with regression analysis and it was found HS gave better result y giving the most minimum DA value compared with regression approach.

  7. Effect of changing polarity of graphite tool/ Hadfield steel workpiece couple on machining performances in die sinking EDM

    Directory of Open Access Journals (Sweden)

    Özerkan Haci Bekir

    2017-01-01

    Full Text Available In this study, machining performance ouput parameters such as machined surface roughness (SR, material removal rate (MRR, tool wear rate (TWR, were experimentally examined and analyzed with the diversifying and changing machining parameters in (EDM. The processing parameters (input par. of this research are stated as tool material, peak current (I, pulse duration (ton and pulse interval (toff. The experimental machinings were put into practice by using Hadfield steel workpiece (prismatic and cylindrical graphite electrodes with kerosene dielectric at different machining current, polarity and pulse time settings. The experiments have shown that the type of tool material, polarity (direct polarity forms higher MRR, SR and TWR, current (high current lowers TWR and enhances MRR, TWR and pulse on time (ton=48□s is critical threshold value for MRR and TWR were influential on machining performance in electrical discharge machining.

  8. Die binding van die konfessie

    Directory of Open Access Journals (Sweden)

    P. J. Coetzee

    1970-05-01

    Full Text Available Ons moet waak teen twee uiterstes. Aan die een kant het die dogma as onversoenlike vyand die dogmatisme en aan die ander kant die antidogmatisme — dit hou enersyds die gevaar in van verabsolutering (oorskatting, en ander- syds die gevaar van relativisme (onderskatting.

  9. Die Region braucht die Kultur - die Kultur braucht die Region

    OpenAIRE

    Klemm, Ulrich

    1995-01-01

    Die Region braucht die Kultur - die Kultur braucht die Region. - In: Region in Aktion - oder: Region im Abseits? - Boxberg-Wölchingen : Eigenständige Regionalentwicklung Baden-Württemberg, 1995. - S. 25 f.

  10. Emission factors of the iron and steel sector for the emission reporting; Emissionsfaktoren zur Eisen- und Stahlindustrie fuer die Emissionsberichterstattung

    Energy Technology Data Exchange (ETDEWEB)

    Hensmann, Michael; Haardt, Sebastian; Ebert, Dominik [Betriebsforschungsinstitut VDEh-Institut fuer Angewandte Forschung GmbH, Duesseldorf (Germany)

    2012-10-15

    The German Umweltbundesamt (UBA) records emission factors of important groups of emitters of the iron- and steelmaking industry in a central database named ''Zentrales System Emissionen'' (ZSE) since 1990. This data is being used for calculations of emission inventories. The main purposes are the generation of forecasts, calculating emissions of other plants and the appraisal of potential measures for reduction of pollution. This makes it possible to identify and appraise future problems and measures. Because of steadily increasing requirements to data quality and quality assurance, it became necessary to update the ZSE with characteristical emission data in order to give a representative view of relevant stages in the iron- and steelmaking industry with respect to emissions. In 2008, the VDEh-Betriebsforschungsinstitut (BFI) was assigned to determine up-to-date emission factors for the following relevant stages in the iron- and steelmaking industry: - sintering plant - coking plant - blast furnace - steel making (differentiated between oxygen and electric steel making) - production of rolled steel Due to a wide diversity of data quality, a consecutive project to determine the corresponding uncertainty of the emission factors was integrated into the ongoing project. This is necessary to create reliable forecasts of emissions and to meet national and international duties of reporting. The project was supported by 18 companies of the German iron- and steelmaking industry. A total of 40 relevant sources of emissions were identified within the five stages of steelmaking and taken into consideration. The emission data for documenting organic and inorganic components of harmful gas, heavy metals and air borne dusts in the ZSE was taken from the reports of emissions 2008 of the supporting companies and made up for a total of 63 plants. Due to a wide variety of data quality the emissions of point sources and diffuse sources are treated separately. While

  11. A study on die wear model of warm and hot forgings

    Science.gov (United States)

    Kang, J. H.; Park, I. W.; Jae, J. S.; Kang, S. S.

    1998-05-01

    Factors influencing service lives of tools in warm and hot forging processes are wear, mechanical fatigue, plastic deformation and thermal fatigue, etc. Wear is the predominant factor for tool failure among these. To predict tool life by wear, Archard's model where hardness is considered as constant or function of temperature is generally applied. Usually hardness of die is a function of not only temperature but operating time of die. To consider softening of die by repeated operation it is necessary to express hardness of die by a function of temperature and time. In this study wear coefficients were measured for various temperatures and heat treatment for H13 tool steel. Also by experiment of reheating of die, die softening curves were obtained. From experimental results, relationships between tempering parameters and hardness were established to investigate effects of hardness decrease by the effect of temperatures and time. Finally modified Archard's wear model in which hardness is considered to be a function of main tempering curve was proposed. And finite element analyses were conducted by adopting suggested wear model. By comparisons of simulations and real profiles of worn die, proposed wear model was verified.

  12. Die nabyheid van die Koninkryk

    Directory of Open Access Journals (Sweden)

    W.J. Snyman

    1963-03-01

    Full Text Available Vanweë die belangrikheid daarvan volg hier ’n breër bespreking van die proefskrif van dr. Tjaart van der Walt oor die nabyheid van die Koninkryk as wat in ’n gewone resensie kan geskied. Die vraagstuk wat onder oë gesien word is so oud as die kerk en die teologie, soms minder en soms meer op die voorgrond. Tans kan gesê word, staan dit in die middelpunt. Daarby is dit nie maar ’n akademiese vraagstuk nie, maar ’n vraagstuk waarvoor elke nadenkende leser van die Skrif te staan kom.

  13. Analysis and modeling of hot extrusion die for its service life enhancement

    Science.gov (United States)

    Akhtar, Syed Sohail

    Aluminum extrusion finds extensive application in the construction, automobile and aerospace industries. High pressures, elevated temperatures, complex and intricate section geometries lead to repeated mechanical and thermal stresses in the die and affiliated tooling. Product rework and rejects can be traced back to various defects spread over the die life cycle: die design, die manufacture and heat treatment, process parameters, inprocess die maintenance/correction and, billet type and quality. Therefore, improved and efficient service life of die and related tooling used in the extrusion press is one the most important factors in maximizing productivity and minimizing cost for ensuring the economical efficiency of an aluminum extrusion plant. How often a die has to be scrapped and replaced with a new one directly contributes to the commercial viability of producing a certain profile. The focus of the current work is on three distinct yet inter-related studies pertaining to the improvement of aluminum extrusion die. Study-A (Die Failure Analysis) is an investigation of various modes and critical failure types based on industrial data (Chapter-2 ), examination of failed dies and finite element simulation for identification of critical process parameters and design features in die fatigue-life (Chapter-3). In Study-B (Die Surface Hardening Treatment), two-stage controlled gas nitriding process for H13 steel is evaluated, both experimentally and numerically, in terms of nitrided case morphology and properties (Chapter-4) followed by experimental and numerical investigation of the effects of repeated nitriding (Chapter-5), pre-nitriding surface preparation (Chapter-6) and die profile geometry (Chapter-7) on nitriding performance in regard to die service life. In Study-C (Effect of Billet Quality on Die Life), the effect of billet quality and related influencing extrusion parameters on the die service life is investigated based on industrial data and some regression

  14. 3D thermal model of laser surface glazing for H13 tool steel

    Science.gov (United States)

    Kabir, I. R.; Yin, D.; Naher, S.

    2017-10-01

    In this work a three dimensional (3D) finite element model of laser surface glazing (LSG) process has been developed. The purpose of the 3D thermal model of LSG was to achieve maximum accuracy towards the predicted outcome for optimizing the process. A cylindrical geometry of 10mm diameter and 1mm length was used in ANSYS 15 software. Temperature distribution, depth of modified zone and cooling rates were analysed from the thermal model. Parametric study was carried out varying the laser power from 200W-300W with constant beam diameter and residence time which were 0.2mm and 0.15ms respectively. The maximum surface temperature 2554°K was obtained for power 300W and minimum surface temperature 1668°K for power 200W. Heating and cooling rates increased with increasing laser power. The depth of the laser modified zone attained for 300W power was 37.5µm and for 200W power was 30µm. No molten zone was observed at 200W power. Maximum surface temperatures obtained from 3D model increased 4% than 2D model presented in author's previous work. In order to verify simulation results an analytical solution of temperature distribution for laser surface modification was used. The surface temperature after heating was calculated for similar laser parameters which is 1689°K. The difference in maximum surface temperature is around 20.7°K between analytical and numerical analysis of LSG for power 200W.

  15. Die topkwark

    Directory of Open Access Journals (Sweden)

    R. Tegen

    1998-07-01

    Full Text Available ’n Oorsig van die belangrikheid van die onlangs ontdekte topkwark by Fermilab in Chicago word gegee. Daar word aangetnon dat die topkwark belangrik is in fisika van die Oerknal, oftewel "Big Bang", en in die Standaard Model van Elementêredeeltjie-fisika. Toepaslike literatuur vir verdere studie kan van die lys van verwysings in hierdie kort, nietegniese artikel, nagegaan word.

  16. Micro-Bulges Investigation on Laser Modified Tool Steel Surface

    Directory of Open Access Journals (Sweden)

    Fauzun Fazliana

    2017-01-01

    Full Text Available This paper presents micro-bulges investigation on laser modified tool steel. The aim of this study is to understand the effect of laser irradiance and interaction time on surface morphology configuration. An Nd:YAG laser system with TEM00 pulse processing mode was used to modify the samples. Metallographic study shows samples were analyzed for focal position effect on melted pool size, angle of peaks geometry and laser modified layer depth. Surface morphology were analyzed for surface roughness. Laser modified layer shows depth ranged between 42.22 and 420.12 μm. Angle of peak bulge was found to be increase with increasing peak power. The maximum roughness, Ra, achieved in modified H13 was 21.10 μm. These findings are significant to enhance surface properties of laser modified steel and cast iron for dies and high wear resistance applications.

  17. Die funksie van die belydenis in die struktuur van die kerk en die ...

    African Journals Online (AJOL)

    Ter wille van die argument wat in hierdie voordrag na vore gebring word, word vier sodanige konstituerende elemente van die kerklike struktuur onderskei, te wete die belydenis, die teologie, die verkondi- ging (meer bepaald die prediking) en die kerkorde (kerkwet volgens ons terminologie). Ons gaan nou elkeen hiervan ...

  18. Die posisie van die Helper in die sending

    Directory of Open Access Journals (Sweden)

    I. J. van der Walt

    1972-05-01

    Full Text Available Gedurende die aanvangsjare van die sending het die helper ’n onmisbare funksie vervul. Hulle het die onherbergsame binnelande geken, waardevolle kontakpunte vir die sendelinge geopen en hulle mense geestelik help voorlig en voorberei.

  19. [Circulation of the influenza A virus of H13 serosubtype among seagulls in the Northern Caspian (1979-1985)].

    Science.gov (United States)

    Iamnikova, S S; Kovtun, T O; Dmitriev, G A; Aristova, V A; Krivonosov, G A; Rusanov, G M; Konechnyĭ, A G; L'vov, D K

    1989-01-01

    The results of seven-year ecologo-virological studies (1979-1985) of Laridae colonies on the island Zhemchuzhnyi, northern Kaspian Sea, showed annual isolation of influenza A viruses. Altogether, 95 hemagglutinating agent have been isolated. Strains with 4 different combinations of surface antigens were identified: H5N2, H13N2, H13N3, H13N6. The possibility of transovarial transmission is confirmed by the fact of isolation of an influenza virus strain A/black-headed herring gull/Astrakhan/458/85 (H13N6) from a nestling having no contacts with the environment. Simultaneous circulation of influenza A viruses (in 1983--H13N2 and H13N6, in 1985.--H13N3 and H13N6) and the presence in the virion of neuraminidase of human influenza virus (N2) allow to consider the isolates to be natural recombinants.

  20. DIE GESKIEDENIS VAN DIE PERSONEELFUNKSIE IN DIE SA ...

    African Journals Online (AJOL)

    stel (kortdiensstelsel). Met die uitbreek van die oorlog in 1939 het die. Unieverdedigingsmag uit 40% Staandemag en. 60% aktiewe Burgermag bestaan. Op 22 Sept. 1939 is magtiging aan die Aktiewe Burgermag- eenhede verleen om vrywilligers vir die duur van die oorlog te aanvaar. Agv beswaar dat die Verdedigingswet.

  1. Die Formatestadt

    OpenAIRE

    Günter Trojan

    2013-01-01

    Zu Zeiten von DV oder VHS (wer kennt das eigentlich noch?) war die Welt noch in Ordnung: Da hatte man eine Kassette in der Hand und wenn das passende Gerät gefunden wurde konnte man das Video auch abspielen. Günter Trojan diskutiert die Geschichte und Gegenwart unterschiedlicher Videoformate ...

  2. Die Formatestadt

    Directory of Open Access Journals (Sweden)

    Günter Trojan

    2013-06-01

    Full Text Available Zu Zeiten von DV oder VHS (wer kennt das eigentlich noch? war die Welt noch in Ordnung: Da hatte man eine Kassette in der Hand und wenn das passende Gerät gefunden wurde konnte man das Video auch abspielen. Günter Trojan diskutiert die Geschichte und Gegenwart unterschiedlicher Videoformate ...

  3. Reparation of damaged forging dies

    Directory of Open Access Journals (Sweden)

    Vukić Lazić

    2015-03-01

    Full Text Available The forging dies are in exploitation exposed to elevated temperatures and variable impact loads, both compressive and shear. Steels for manufacturing of these tools must endure those loads while maintaining mechanical properties and being resistant to wear and thermal fatigue. For those reasons, the alloyed steels are used for making the forging dies, though they have less weldability, because alloying increases proneness to hardening. Any reparatory hard facing (HF of the damaged dies would require the specially adjusted technology to the particular piece. In this paper reparatory hard facing of dies used for forging pieces in the automobile industry is considered. Prior to reparatory hard facing of the real tools, numerous experimental hard facings on models were performed. All the model hard facings were done on the same steels which were used for production of the real forging dies. To define the optimal hard facing technology one needs to derive the optimal combination of the adequate heat treatment(s, to select the proper filler metals and the welding procedure. The established optimal HF technology was applied to real forging dies whose service life was further monitored in conditions of exploitation

  4. LongerLife products increase the sustainability. Is corrosion protection ecologically useful for steel components?; LongerLife-Produkte erhoehen die Nachhaltigkeit. Ist Korrosionsschutz von Stahlbauteilen oekologisch sinnvoll?

    Energy Technology Data Exchange (ETDEWEB)

    Rogall, Armin Dietmar [Fachhochschule Dortmund (Germany). Fachbereich Architektur

    2011-07-01

    The installation of hot-dip galvanized construction units means sustainable acting. Since corrosion protection by hot-dip galvanizing can be particularly named sustainable due to its longevity, its environmental careful production, its recycling ability and life extension of steel components. Particularly the reduction of the maintenance cycles and utilization costs accompanying with a slightly higher initial investment makes the hot-dip galvanizing a sustainable system. Steel components which are treated with galvanization and colour coating, have a maintenance-free life span of more than 80 years.

  5. Isolation of H13N2 influenza A virus from turkeys and surface water.

    Science.gov (United States)

    Sivanandan, V; Halvorson, D A; Laudert, E; Senne, D A; Kumar, M C

    1991-01-01

    This is the first report of the isolation of H13N2 avian influenza virus (AIV) subtype from domestic turkeys. This subtype was also isolated from nearby surface water. The observation of large numbers of gulls in close association with turkeys on range before the virus isolations suggests that this virus subtype was transmitted from gulls to range turkeys. Turkey flocks infected by this virus subtype did not show any clinical signs of the disease, although seroconversion did occur. The H13N2 isolates were found to be non-pathogenic in chickens.

  6. Imaging the water snowline in a protostellar envelope with H13CO+

    Science.gov (United States)

    van 't Hoff, Merel L. R.; Persson, Magnus V.; Harsono, Daniel; Taquet, Vianney; Jørgensen, Jes K.; Visser, Ruud; Bergin, Edwin A.; van Dishoeck, Ewine F.

    2018-05-01

    Context. Snowlines are key ingredients for planet formation. Providing observational constraints on the locations of the major snowlines is therefore crucial for fully connecting planet compositions to their formation mechanism. Unfortunately, the most important snowline, that of water, is very difficult to observe directly in protoplanetary disks because of the close proximity of this snowline to the central star. Aims: Based on chemical considerations, HCO+ is predicted to be a good chemical tracer of the water snowline because it is particularly abundant in dense clouds when water is frozen out. This work aims to map the optically thin isotopolog H13CO+ toward the envelope of the low-mass protostar NGC 1333-IRAS2A, where the snowline is at a greater distance from the star than in disks. Comparison with previous observations of H218O show whether H13CO+ is indeed a good tracer of the water snowline. Methods: NGC 1333-IRAS2A was observed using the NOrthern Extended Millimeter Array (NOEMA) at 0.''9 resolution, targeting the H13CO+ J = 3 - 2 transition at 260.255 GHz. The integrated emission profile was analyzed using 1D radiative transfer modeling of a spherical envelope with a parametrized abundance profile for H13CO+. This profile was validated with a full chemical model. Results: The H13CO+ emission peaks 2'' northeast of the continuum peak, whereas H218O shows compact emission on source. Quantitative modeling shows that a decrease in H13CO+ abundance by at least a factor of six is needed in the inner 360 AU to reproduce the observed emission profile. Chemical modeling indeed predicts a steep increase in HCO+ just outside the water snowline; the 50% decrease in gaseous H2O at the snowline is not enough to allow HCO+ to be abundant. This places the water snowline at 225 AU, further away from the star than expected based on the 1D envelope temperature structure for NGC 1333-IRAS2A. In contrast, DCO+ observations show that the CO snowline is at the expected

  7. The induction furnace as a melting facility in steel production. Pt. 1. Features of induction furnaces used in steel production; Der Induktionsofen als Schmelzaggregat fuer die Stahlerzeugung. T. 1. Merkmale von Induktionsoefen in der Stahlerzeugung

    Energy Technology Data Exchange (ETDEWEB)

    Chaabet, Mohamed; Doetsch, Erwin [ABP Induction Systems GmbH, Dortmund (Germany)

    2011-12-15

    Global steel output has now been growing extremely rapidly for a prolonged time; in the past ten years alone, annual production has risen from 851 million t/a (in 2001) to 1417 million t/a (2010), as a result, primarily, of growth in China. Electric steel production using the electric arc furnace as the classical melting facility is around 45 % world-wide, with a rising trend (but excluding the special case of China, where oxygen-route steel holds a 90 % share of production). Following the development of induction technology and inverter outputs of over 40 MW for crucible furnaces with capacities of above 65 t, the induction furnace is now available as an alternative electrical melting installation for use in smaller mini steel mills. The benefits of this technology can be found in high feed-material efficiencies and low environmental and workplace burdens, in addition to the absence of electrode costs and the only modest demands made on the power-supply grid. These features of the induction furnace and their special significance for steel production are examined in Part 1 of this article. The second part of the article then focuses on examples of the use of induction furnaces in the steelmaking plant. (orig.)

  8. (1 H, 13 C and 31 P) NMR of phosphonic acid derivatives

    International Nuclear Information System (INIS)

    Campos, Valdevino; Costa, Valentim E. Uberti

    1991-01-01

    In the last years the development of phosphates analogues in the medical and agricultural pesticides has being very expressive. 1 H, 13 C and mainly 31 P NMR are used for stereochemical and conformational analysis, and reactivity studies on the compounds resulting from those chemical processes

  9. Die funksie van die skeppingstradisie in die boek Jeremia

    African Journals Online (AJOL)

    gedeeites voor wat sterk ooreenkomste toon met die beskrywings van die skep pingsgebeure in die boek Jeremia. • Volgpns Von Rad (1957:144-146) het daar wel 'n groep bestaan wat belange ge- had liet by die oorlewering van die skeppingstradisies. Dit was waarskynlik die. Sadokitiese priesters wat om twee redes aan ...

  10. Tribological and Wear Performance of Nanocomposite PVD Hard Coatings Deposited on Aluminum Die Casting Tool

    Directory of Open Access Journals (Sweden)

    Jose Mario Paiva

    2018-02-01

    Full Text Available In the aluminum die casting process, erosion, corrosion, soldering, and die sticking have a significant influence on tool life and product quality. A number of coatings such as TiN, CrN, and (Cr,AlN deposited by physical vapor deposition (PVD have been employed to act as protective coatings due to their high hardness and chemical stability. In this study, the wear performance of two nanocomposite AlTiN and AlCrN coatings with different structures were evaluated. These coatings were deposited on aluminum die casting mold tool substrates (AISI H13 hot work steel by PVD using pulsed cathodic arc evaporation, equipped with three lateral arc-rotating cathodes (LARC and one central rotating cathode (CERC. The research was performed in two stages: in the first stage, the outlined coatings were characterized regarding their chemical composition, morphology, and structure using glow discharge optical emission spectroscopy (GDOES, scanning electron microscopy (SEM, and X-ray diffraction (XRD, respectively. Surface morphology and mechanical properties were evaluated by atomic force microscopy (AFM and nanoindentation. The coating adhesion was studied using Mersedes test and scratch testing. During the second stage, industrial tests were carried out for coated die casting molds. In parallel, tribological tests were also performed in order to determine if a correlation between laboratory and industrial tests can be drawn. All of the results were compared with a benchmark monolayer AlCrN coating. The data obtained show that the best performance was achieved for the AlCrN/Si3N4 nanocomposite coating that displays an optimum combination of hardness, adhesion, soldering behavior, oxidation resistance, and stress state. These characteristics are essential for improving the die mold service life. Therefore, this coating emerges as a novelty to be used to protect aluminum die casting molds.

  11. Tribological and Wear Performance of Nanocomposite PVD Hard Coatings Deposited on Aluminum Die Casting Tool.

    Science.gov (United States)

    Paiva, Jose Mario; Fox-Rabinovich, German; Locks Junior, Edinei; Stolf, Pietro; Seid Ahmed, Yassmin; Matos Martins, Marcelo; Bork, Carlos; Veldhuis, Stephen

    2018-02-28

    In the aluminum die casting process, erosion, corrosion, soldering, and die sticking have a significant influence on tool life and product quality. A number of coatings such as TiN, CrN, and (Cr,Al)N deposited by physical vapor deposition (PVD) have been employed to act as protective coatings due to their high hardness and chemical stability. In this study, the wear performance of two nanocomposite AlTiN and AlCrN coatings with different structures were evaluated. These coatings were deposited on aluminum die casting mold tool substrates (AISI H13 hot work steel) by PVD using pulsed cathodic arc evaporation, equipped with three lateral arc-rotating cathodes (LARC) and one central rotating cathode (CERC). The research was performed in two stages: in the first stage, the outlined coatings were characterized regarding their chemical composition, morphology, and structure using glow discharge optical emission spectroscopy (GDOES), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. Surface morphology and mechanical properties were evaluated by atomic force microscopy (AFM) and nanoindentation. The coating adhesion was studied using Mersedes test and scratch testing. During the second stage, industrial tests were carried out for coated die casting molds. In parallel, tribological tests were also performed in order to determine if a correlation between laboratory and industrial tests can be drawn. All of the results were compared with a benchmark monolayer AlCrN coating. The data obtained show that the best performance was achieved for the AlCrN/Si₃N₄ nanocomposite coating that displays an optimum combination of hardness, adhesion, soldering behavior, oxidation resistance, and stress state. These characteristics are essential for improving the die mold service life. Therefore, this coating emerges as a novelty to be used to protect aluminum die casting molds.

  12. Die regsposisie van die gemolesteerde kind 1

    Directory of Open Access Journals (Sweden)

    P.J. Schabort

    1991-03-01

    Full Text Available Hoe reik die reg uit na die seksueel gemolesteerde kind? As na die reg in wye verband gekyk word, sou dit alie wetgewing en alle gemeneregsbeginsels en alle regsprosedures insluit waardeur die Staat poog om molestering te voorkom en die gemolesteerde kind in beskerming te neem. Dit le baie wyd en sou byvoorbeeld die maatreels insluit van die Kindenvet 33 van 1960; die Wet op Egskeiding 70 van 1979; die Wet op Kindersorg 74 van 1983; die Wet op die Status van Kinders 82 van 1987 en die Wet op Bemiddeling in Sekere Egskeidingsaangeleenthede 24 van 1987. Eersdaags sal dit moontlik ook ’n Manifes vir die Regte van Kinders insluit wat vermoedelik geskoei sal wees op die W O se Konvensie vir die Regte van die Kind (1989 w a arv an die RSA tan s nog nie ’n ondertekenaar is nie.

  13. THE DEVELOPMENT OF TECHNOLOGY OF THE CORE THERMO-MECHANICALLY HARDENED REINFORC-ING STEEL OF GRADE A700HW OF DIE-ROLLED SECTION NO 12, 14, 16 PRODUCTION ACCORDING TO REQUIREMENT OF FINNISH STANDARDS SFST1216 IN CONDITIONS OF SMALL-SECTION MILL 320 OF RUP «BMZ»

    Directory of Open Access Journals (Sweden)

    A. V. Rusalenko

    2009-01-01

    Full Text Available The development of technology of the core thermomechanically hardened reinforcing steel of grade А700HW of die-rolled section No 12, 14, 16 production according to requirement of Finnish standards SFST1216 in conditions of small-section mill 320 of RUP «BMZ» is given.

  14. H12CN and H13CN excitation analysis in the circumstellar outflow of R Sculptoris

    Science.gov (United States)

    Saberi, M.; Maercker, M.; De Beck, E.; Vlemmings, W. H. T.; Olofsson, H.; Danilovich, T.

    2017-03-01

    Context. The 12CO/13CO isotopologue ratio in the circumstellar envelope (CSE) of asymptotic giant branch (AGB) stars has been extensively used as the tracer of the photospheric 12C/13C ratio. However, spatially-resolved ALMA observations of R Scl, a carbon rich AGB star, have shown that the 12CO/13CO ratio is not consistent over the entire CSE. Hence, it can not necessarily be used as a tracer of the 12C/13C ratio. The most likely hypothesis to explain the observed discrepancy between the 12CO/13CO and 12C/13C ratios is CO isotopologue selective photodissociation by UV radiation. Unlike the CO isotopologue ratio, the HCN isotopologue ratio is not affected by UV radiation. Therefore, HCN isotopologue ratios can be used as the tracer of the atomic C ratio in UV irradiated regions. Aims: We aim to present ALMA observations of H13CN(4-3) and APEX observations of H12CN(2-1), H13CN(2-1, 3-2) towards R Scl. These new data, combined with previously published observations, are used to determine abundances, ratio, and the sizes of line-emitting regions of the aforementioned HCN isotopologues. Methods: We have performed a detailed non-LTE excitation analysis of circumstellar H12CN(J = 1-0, 2-1, 3-2, 4-3) and H13CN(J = 2-1, 3-2, 4-3) line emission around R Scl using a radiative transfer code based on the accelerated lambda iteration (ALI) method. The spatial extent of the molecular distribution for both isotopologues is constrained based on the spatially resolved H13CN(4-3) ALMA observations. Results: We find fractional abundances of H12CN/H2 = (5.0 ± 2.0) × 10-5 and H13CN/H2 = (1.9 ± 0.4) × 10-6 in the inner wind (r ≤ (2.0 ± 0.25) ×1015 cm) of R Scl. The derived circumstellar isotopologue ratio of H12CN/H13CN = 26.3 ± 11.9 is consistent with the photospheric ratio of 12C/13C 19 ± 6. Conclusions: We show that the circumstellar H12CN/H13CN ratio traces the photospheric 12C/13C ratio. Hence, contrary to the 12CO/13CO ratio, the H12CN/H13CN ratio is not affected by UV

  15. Improved Method for the Isolation of Biosurfactant Glycolipids from Rhodococcus sp. Strain H13A

    OpenAIRE

    Bryant, Frank O.

    1990-01-01

    An improved method for the isolation of the biosurfactant glycolipids from Rhodococcus sp. strain H13A by using XM 50 diafiltration and isopropanol precipitation was devised. This procedure was advantageous since it removes protein coisolated when the glycolipids are obtained by organic extraction and silicic acid chromatography. The protein apparently does not contribute any biosurfactant characteristics to the glycolipids. The deacylated glycolipid backbone included only a disaccharide.

  16. Die rol van die blanke werker in die motivering van die swart werker

    Directory of Open Access Journals (Sweden)

    G. J. Oosthuizen

    1980-11-01

    Opsomming Die motivering van die Swart werker kan nie in die huidige situasie in isolasie bestudeer word nie, omdat die Blanke werker steeds in die bestuursposisie is en daarom die motivering van die Swart werker kan beïnvloed. Hierdie ondersoek was daarop gerig om die rol van die Blanke werker in die motivering van die Swart werker nader te ondersoek. Die houding en die leierskapsbenadering van die Blanke werker teenoor die Swart werker is gemeet, asook die behoeftes wat volgens die Blanke werker by die Swart werker bestaan, bevredig is, of nie bestaan nie. Die behoeftes van Swart werkers, soos deur hulleself gesien, is ook ondersoek. Ten opsigte van sekere aspekte is beduidende verskille gevind.

  17. Interferometric imaging of Titan's HC$_3$N, H$^{13}$CCCN and HCCC$^{15}$N

    OpenAIRE

    Cordiner, M. A.; Nixon, C. A.; Charnley, S. B.; Teanby, N. A.; Molter, E. M.; Kisiel, Z.; Vuitton, V.

    2018-01-01

    We present the first maps of cyanoacetylene isotopologues in Titan's atmosphere, including H$^{13}$CCCN and HCCC$^{15}$N, detected in the 0.9 mm band using the Atacama Large Millimeter/submillimeter array (ALMA) around the time of Titan's (southern winter) solstice in May 2017. The first high-resolution map of HC$_3$N in its $v_7=1$ vibrationally excited state is also presented, revealing a unique snapshot of the global HC$_3$N distribution, free from the strong optical depth effects that adv...

  18. Comparative Investigation on Tool Wear during End Milling of AISI H13 Steel with Different Tool Path Strategies

    Science.gov (United States)

    Adesta, Erry Yulian T.; Riza, Muhammad; Avicena

    2018-03-01

    Tool wear prediction plays a significant role in machining industry for proper planning and control machining parameters and optimization of cutting conditions. This paper aims to investigate the effect of tool path strategies that are contour-in and zigzag tool path strategies applied on tool wear during pocket milling process. The experiments were carried out on CNC vertical machining centre by involving PVD coated carbide inserts. Cutting speed, feed rate and depth of cut were set to vary. In an experiment with three factors at three levels, Response Surface Method (RSM) design of experiment with a standard called Central Composite Design (CCD) was employed. Results obtained indicate that tool wear increases significantly at higher range of feed per tooth compared to cutting speed and depth of cut. This result of this experimental work is then proven statistically by developing empirical model. The prediction model for the response variable of tool wear for contour-in strategy developed in this research shows a good agreement with experimental work.

  19. Die hervertolking van die paradigma in verband met die ...

    African Journals Online (AJOL)

    Kerkorde van De Mist en die Algemene Reglement van 1816, wat onderskeidelik vir die Kaapse Kerk en die .... Een van die eerstes was Sam Freiherr von Pufendorf (1632-1694) wat in sy werk De habitu religionis ..... Koning was weer aan bewind (vgl Diepenhorst sj:74w; De Visser 1926/1927 lll:202w). 43.1 JD Janssen ...

  20. die heidelbergse kategismus en die kategesemateriaal van die ned

    African Journals Online (AJOL)

    subjek, objek, leerstof en die metodiek van die senior kategese. Bloemfontein: Algemene Jeugkommissie Sondagskoolboekhandel. de rAAd oer ned ger kerken in Zuid AfrikA. 1921. De zevende vergadering: handelinge. 1925. De negende vergadering: handelinge. de villierS, d. W. 1957. Die Kategese in die Ned. Geref.

  1. die sinodale verband van die nederduitse gereformeerde kerk in die

    African Journals Online (AJOL)

    Liezel

    Strauss. Die sinodale verband van die Nederduitse Gereformeerde Kerk. 122 die Vrystaatse Sinode anti-veranderingsgesind of eerder gesond-behoudend of gereformeerd-gematig? Veral as dit .... howe) in moeilike omstandighede gebring is (NG Kerk in die OVS 1865-1912:5). In 'n brief op 8 Augustus 1864 ontken Ds.

  2. Die kerkregtelike posisie van die ouderling en diaken in die ...

    African Journals Online (AJOL)

    ... drie dekades die Kerkreg gevestig as 'n selfstandige vak in die teologiese curriculum, maar ook 'n baie groot rol gespeel daarin dat die beginsels van die kerk like reg beter begryp word. Naas sy wetenskaplike bydrae word met eweveel genoegdoening gedink aan sy bcsondere persoonlikheid, sy werkvermoe, sy humor-.

  3. Spark Plasma Co-Sintering of Mechanically Milled Tool Steel and High Speed Steel Powders.

    Science.gov (United States)

    Pellizzari, Massimo; Fedrizzi, Anna; Zadra, Mario

    2016-06-16

    Hot work tool steel (AISI H13) and high speed steel (AISI M3:2) powders were successfully co-sintered to produce hybrid tool steels that have properties and microstructures that can be modulated for specific applications. To promote co-sintering, which is made difficult by the various densification kinetics of the two steels, the particle sizes and structures were refined by mechanical milling (MM). Near full density samples (>99.5%) showing very fine and homogeneous microstructure were obtained using spark plasma sintering (SPS). The density of the blends (20, 40, 60, 80 wt % H13) was in agreement with the linear rule of mixtures. Their hardness showed a positive deviation, which could be ascribed to the strengthening effect of the secondary particles altering the stress distribution during indentation. A toughening of the M3:2-rich blends could be explained in view of the crack deviation and crack arrest exerted by the H13 particles.

  4. Riglyne vir die onderwys.

    Directory of Open Access Journals (Sweden)

    J. L. du Plooy

    1960-03-01

    Full Text Available In die afgelope vyftig jaar sedert die Unie tot stand gekom het, is veel op die gebied van onderwys tot stand gebring. Dit is heel natuurlik dat ’n mens sou vra: Wat van die toekoms?

  5. Die partypolitiek en die toekoms van die Afrikaanse volkskultuur

    Directory of Open Access Journals (Sweden)

    A.P. Treurnicht

    1970-03-01

    Full Text Available Reeds in 1853 het die Zuid Afrikaan hom soos volg uitgelaat: „Dis ’n dwaling wat ons reeds meermale bestry het dat ons as Britse onderdane verplig sou wees, om die Britse nasionaliteit ons s’n te maak. Die Kolonis van Hollandse oorsprong kan geen Engelsman word nie, en moet ook geen Nederlander wil wees nie. Wanneer hy weet om sy standpunt te waardeer, dan sal hy as verligte kolonis die grondtrekke van die Engelse volkskarakter met dié van die Nederlandse harmonies leer verenig en daardeur word wat hy as Kapenaar moet word.”

  6. The synthesis of Org 3770 labelled with 3H, 13C and 14C

    International Nuclear Information System (INIS)

    Kaspersen, F.M.; Rooij, F.A.M. van; Sperling, E.G.M.; Wieringa, J.H.

    1989-01-01

    The syntheses of 1,2,3,4,10,14b-hexahydro-2-methylpyrazino[2,1-a]pyrido[2,3-c][2]benazepine (Org 3770) labelled with 3 H (and 2 H), 13 C and 14 C are described. Tritiated Org 3770 was prepared either by exchange under alkaline conditions with tritiated water or catalytic reductive dehalogenation of a chloro analogue with 3 H 2 . 13 C-labelled material was obtained in a seven-step synthesis starting from 13 C-labelled benzene whereas 14 C-Org 3770 was prepared in a three-step synthesis starting with 14 CO 2 . All labelled compounds were analyzed by TLC, HPLC, MS and NMR. (author)

  7. 1H-13C NMR-based profiling of biotechnological starch utilization

    DEFF Research Database (Denmark)

    Sundekilde, Ulrik K.; Meier, Sebastian

    2016-01-01

    Starch is used in food-and non-food applications as a renewable and degradable source of carbon and energy. Insight into the chemical detail of starch degradation remains challenging as the starch constituents amylose and amylopectin are homopolymers. We show that considerable molecular detail...... of starch fragmentation can be obtained from multivariate analysis of spectral features in optimized 1H-13C NMR spectroscopy of starch fragments to identify relevant features that distinguish processes in starch utilization. As a case study, we compare the profiles of starch fragments in commercial beer...... samples. Spectroscopic profiles of homooligomeric starch fragments can be excellent indicators of process conditions. In addition, differences in the structure and composition of starch fragments have predictive value for down-stream process output such as ethanol production from starch. Thus, high...

  8. Die Voortrekker-Monument

    Directory of Open Access Journals (Sweden)

    Gerard Moerdyk

    1938-03-01

    Full Text Available Die Eeufeesjaar is vir die Afrikaner ’n tydperk van besieling. Nog nooit sedert die ontstaan van ons volk het een enkele gebeurtenis soveel nasietrots gewek as die honderdjarige herdenking van die Groot Trek. Vir die eerste keer in ons geskiedenis voel ons ons nie meer Kapenaars, Vrystaters, Natalers, en Transvalers nie, maar Afrikaners, saamgesnoer deur die tradisies van ’n selfstandige kultuurvolk. Wanneer die klimaks van die Ossewatrek met die hocksteenlegging van die Voortrekker-Monument bereik word, sal die besieling nie uitsterf nie, die krag wat geskep is sal bly voortgroei tot ’n onweerstaanbare mag. Die Afrikaner sal homself vind, en as die Monument na sowat vyf jaar onthul word, sal die saad wat in hierdie jaar gesaai is, tot voile rypheid gekom het. Dan sal die Monument self tot die volk spreek; intussen egter, is dit wenslik, nee noodsaaklik selfs, om die Monument aan die Afrikaners te verklaar, om ‘n uiteensetting te gee van die noodsaaklikheid van so ’n Monument, sowel as om die motief te verduidelik wat as inspirasie gedien het vir die ontwerpdaar van.

  9. Die Britse owerheid en die onderwys op Heidelberg gedurende die ...

    African Journals Online (AJOL)

    The establishment of Christian National Education (CNE) Schools stimulated the concept of mother tongue education. Oor die klaskamerpraktyk en die werklike gehalte van onderrig tydens die kampskooltydperk is daar min bekend. Heidelberg wat na 1902 in 'n belangrike onderwyssentrum in Transvaal ontwikkel het, het ...

  10. Die belangrikste kenmerk van die diereproduksie- bedrywe oor die ...

    African Journals Online (AJOL)

    digdhede teen 1980 uit 'n kudde van 30 rnilj.skape ge- produseer moet word. Tweedens sal die faktore ... die Republiek van Suid-Mrika teen 1980 in totaal 28 milj. sal wees. Indien die produsente dit as 'n ..... Appendix Table 4 in Digestive Physiology and nutrition of ruminants Vol. 3 Ed. and Publ. D.C. Church, Oregon State ...

  11. DIE ROL VAN DIE TAALWETENSKAP IN DIE ONTWIKKELING VAN ...

    African Journals Online (AJOL)

    aanslag op die sogenaamde "Intentional Fallacy", heelwat verder. n. Mens sou hier eintlik ook op die invloed van Lacan se toepassing van. De Sacs sure op Freud moet wys, en op Macherey se Theory of Literary. Production. Barthes is naamlik besig om repressie teen te werk, en die teks as produksieproses in stede van ...

  12. Development of materials for the rapid manufacture of die cast tooling

    Science.gov (United States)

    Hardro, Peter Jason

    The focus of this research is to develop a material composition that can be processed by rapid prototyping (RP) in order to produce tooling for the die casting process. Where these rapidly produced tools will be superior to traditional tooling production methods by offering one or more of the following advantages: reduced tooling cost, shortened tooling creation time, reduced man-hours for tool creation, increased tool life, and shortened die casting cycle time. By utilizing RP's additive build process and vast material selection, there was a prospect that die cast tooling may be produced quicker and with superior material properties. To this end, the material properties that influence die life and cycle time were determined, and a list of materials that fulfill these "optimal" properties were highlighted. Physical testing was conducted in order to grade the processability of each of the material systems and to optimize the manufacturing process for the downselected material system. Sample specimens were produced and microscopy techniques were utilized to determine a number of physical properties of the material system. Additionally, a benchmark geometry was selected and die casting dies were produced from traditional tool materials (H13 steel) and techniques (machining) and from the newly developed materials and RP techniques (selective laser sintering (SLS) and laser engineered net shaping (LENS)). Once the tools were created, a die cast alloy was selected and a preset number of parts were shot into each tool. During tool creation, the manufacturing time and cost was closely monitored and an economic model was developed to compare traditional tooling to RP tooling. This model allows one to determine, in the early design stages, when it is advantageous to implement RP tooling and when traditional tooling would be best. The results of the physical testing and economic analysis has shown that RP tooling is able to achieve a number of the research objectives, namely

  13. Wêreldmededingendheid en die tegnologie

    Directory of Open Access Journals (Sweden)

    C. W. I. Pistorius

    1996-07-01

    Full Text Available Afgesien van die interne uitdagings wat die Heropbou- en Ontwikkelingsprogram (HOP aan Suid-Afrika bied, moet die land ook tred hou met die veranderende globale omgewing, spesifiek die toenemende belangrikheid van ekonomiese sekuriteit as komponent van nasionale sekuriteit. Die konsep van mededingendheid vergestalt die doelwit wat nagestreef moet word ten einde die ontluikende globale ekonomiese stryd aan te durf. As ’n belangrike drywer van ekonomiese welvaart is tegnologie een van die belangrikste sleutels tot internasionale mededingendheid. Tegnologiese innovasie is die proses wat as hefboom hiervoor gebruik moet word. Dit is egter nodig dat tegnologie, en spesifiek die proses van tegnologiese innovasie, formeel en gestruktureerd bestuur moet word, sowel op nasionale as firmavlak. Op nasionale vlak is die voorsiene Nasionale Innovasiestelsel beslis ’n stap in die regte rigting.

  14. die ontstaan en die ontwikkeling van die skoolkadette-stelsel in die rsa

    African Journals Online (AJOL)

    toe algemene diensplig ingestel is. Die diens- plig het intussen sy volle beslag gekry en in. Weermagkringe het die gedagte posgevat dat skoolkadette. 'n deeglike ondersoek vereis ten einde die skoolgaande seun vir sy komende nasionale diensplig te orienteer. Tydens kadetopleldlng leer die seuns al die fynere kunsles ...

  15. Van die Gasredakteur

    African Journals Online (AJOL)

    cherish and teach.'1. Die Fakulteit Geneeskunde van die Universiteit van die Oranje-Vrystaat het pragtig gegroei ge- durende die eerste 21 jaar van sy bestaan. Die entoesiasme, doelgerigtheid, harde werk en inisia- tiewe van 'n groot aantal persone was hiervoor verantwoordelik. 'If we see a bit more clearly than they, it is ...

  16. Halfkrone vir die Nagmaal

    African Journals Online (AJOL)

    Owner

    die omgewing van Velddrif en Laaiplek, ook noordwaarts verby Lambertsbaai tot by. Doringbaai en Strandfontein. “Haar seeverhale is Sussie (Kotze) se belangrikste bydrae tot die Afrikaanse letterkunde”, sê Kotzé-Myburgh in die voorwoord van die versamelbundel. Die leser word herinner aan Kotze se debuutroman, ...

  17. Affordable uniform isotope labeling with 2H, 13C and 15N in insect cells

    International Nuclear Information System (INIS)

    Sitarska, Agnieszka; Skora, Lukasz; Klopp, Julia; Roest, Susan; Fernández, César; Shrestha, Binesh; Gossert, Alvar D.

    2015-01-01

    For a wide range of proteins of high interest, the major obstacle for NMR studies is the lack of an affordable eukaryotic expression system for isotope labeling. Here, a simple and affordable protocol is presented to produce uniform labeled proteins in the most prevalent eukaryotic expression system for structural biology, namely Spodoptera frugiperda insect cells. Incorporation levels of 80 % can be achieved for 15 N and 13 C with yields comparable to expression in full media. For 2 H, 15 N and 2 H, 13 C, 15 N labeling, incorporation is only slightly lower with 75 and 73 %, respectively, and yields are typically twofold reduced. The media were optimized for isotope incorporation, reproducibility, simplicity and cost. High isotope incorporation levels for all labeling patterns are achieved by using labeled algal amino acid extracts and exploiting well-known biochemical pathways. The final formulation consists of just five commercially available components, at costs 12-fold lower than labeling media from vendors. The approach was applied to several cytosolic and secreted target proteins

  18. Applications of stable isotopes of 2H, 13C and 15N to clinical problems

    International Nuclear Information System (INIS)

    Klein, P.D.; Szczepanik, P.A.; Hachey, D.L.

    1974-01-01

    The function of the Argonne Program is to provide synthetic, analytical instrumental capability in a core facility for the clinical investigator who needs to use 2 H, 13 C, or 15 N labelled compounds for metabolic or clinical research on pregnant women, newborn infants, young children, or for mass screening. To carry out such application development, there were six stages which were recurrent steps in every application. Five fundamental strategies should be adopted to establish the use of stable isotopes in clinical work. The instrument required for measurements was a combined gas chromatograph-mass spectrometer, and its use was schematically illustrated. Some of the successful experiences with compounds labelled by stable isotopes, such as deuterium labelled chenodeoxycholic acid, and respective 13 C and 15 N-labelled glycine were described. Deutrium labelled bile acid enabled easy and safe determination of the size of the bile acid pool and the replacement rate, providing clearer diagnoses for cholestatic liver disease and gallstones. 13 C and 15 N labelled compounds were used in clinical studies, of children with genetic disorders of amino acid metabolism, i.e., non ketotic hyperflycinemia, B 12 -responsive methyl malonic acidemia, and Lesch-Nyhan syndrome. 15 N-labelled glycine was also studied in a child with Lesch-Nyhan syndrome. (Mukohata, S.)

  19. Cutting Temperature Investigation of AISI H13 in High Speed End Milling

    Directory of Open Access Journals (Sweden)

    Muhammad Riza

    2016-10-01

    Full Text Available Heat produced at the tool-chip interface during high speed milling operations have been known as a significant factor that affect to tool life and workpiece geometry or properties. This paper aims to investigate cutting temperature behaviours of AISI H13 (48 HRC under high speed machining circumstances during pocketing. The experiments were conducted on CNC vertical machining centre by using PVD coated carbide insert. Milling processes were done at cutting speeds 150, 200 and 250 m/min and feed rate were 0.05, 0.1 and 0.15 mm/tooth. Depths of cut applied were 0.1, 0.15 and 0.2 mm. Tool path method applied in this experiment was contour in. Results presented in this paper indicate that by increasing cutting speed the cutting temperature is lower than low cutting speed. However, by decreasing feed rate leads to cutting temperature low. Cutting temperature phenomena at the corner of pocket milling were also investigated. The phenomena showed that cutting temperature tends to decrease a moment when cutter comes to the corner of pocket and turning point of tool path and increase extremely a moment before leaving the corner and turning point.

  20. Die teologie in gesprek met die ekonomie

    African Journals Online (AJOL)

    (1723-1790) sy vertrekpunt neem, ontwikkel, as oorwinnaars uit die Franse Revolu .... Die onmiddellike sukses van Adam Smith se 'Wealth of Nations' was .... alle vorme van sosialisme niks anders as 'kommunisme' (Wassenaar 1977:12) nie.

  1. Dimensional and material characteristics of direct deposited tool steel by CO II laser

    Science.gov (United States)

    Choi, J.

    2006-01-01

    Laser aided direct metalimaterial deposition (DMD) process builds metallic parts layer-by-layer directly from the CAD representation. In general, the process uses powdered metaUmaterials fed into a melt pool, creating fully dense parts. Success of this technology in the die and tool industry depends on the parts quality to be achieved. To obtain designed geometric dimensions and material properties, delicate control of the parameters such as laser power, spot diameter, traverse speed and powder mass flow rate is critical. In this paper, the dimensional and material characteristics of directed deposited H13 tool steel by CO II laser are investigated for the DMD process with a feedback height control system. The relationships between DMD process variables and the product characteristics are analyzed using statistical techniques. The performance of the DMD process is examined with the material characteristics of hardness, porosity, microstructure, and composition.

  2. Die dogmatiese binding van die prediking

    African Journals Online (AJOL)

    genoemde probleemstelling wat ons homileties na riglyne wil soek, sonder die pretensie dat finale oplossings gevind sal word. Om hierdie probleem te ontleed is dit nodig om eers kortliks 'n begripsbepaling van die begrippe dogma, binding en prediking te maak. Vanuit die begripsbepaling kan ons dan probeer vasstel wat ...

  3. DIE PERSOON VAN VREDE IN DIE SENDING

    African Journals Online (AJOL)

    aan dat 'n lewe onder die gesag van God tot volle vrede lei: “In coming under the rule of Yahweh, moreover, life was made whole and safe.” Dit is spesifiek in die tempel waar die volheid van God se vrede ondervind word (1997:662):. The temple is indeed the place where Israel entered into Yahweh's full zone of shalom.

  4. n Oorsig van die huidige stand van navorsing oor die

    African Journals Online (AJOL)

    Test

    7 Jun 2011 ... Die eerste maal wat dit as deel van die teks van 1 Johannes aangehaal word, is in die. 4de eeu in 'n Latynse teks, Liber Apologeticus (hf 4). Eers aan die einde van die 16de eeu is dit in 'n amptelike Katolieke uitgawe van die Vulgaat ingesluit. Die doel van die Johannesbriewe. Waarom is die Briewe ...

  5. Die Ware Buch und die Philologie

    Directory of Open Access Journals (Sweden)

    Bernhard Hurch

    2017-10-01

    Full Text Available Die im 19. Jahrhundert sich verändernden Produktionsbedingungen für Druckwerke (Buchdruck, Satz, Papier, Bindung wirkten katalysierend auf die Fachkonstitution und Institutionalisierung der Philologien. Hier steht der tatsächliche Buchmarkt im Vordergrund der Darstellung, das Käuferpublikum und die Voraussetzungen des Vertriebs. Dazu gehören auch die Rezension als entstehende Textsorte und die rasch arbeitenden Rezensionsorgane. F.-R. Hausmann wurde in den letzten Jahren unentbehrlicher Mitarbeiter dieses im Rahmen des Grazer Schuchardt-Projekts "Netzwerk des Wissens" angesiedelten Ansatzes.

  6. Perdeuteration and methyl-selective 1H, 13C-labeling by using a Kluyveromyces lactis expression system

    International Nuclear Information System (INIS)

    Miyazawa-Onami, Mayumi; Takeuchi, Koh; Takano, Toshiaki; Sugiki, Toshihiko; Shimada, Ichio; Takahashi, Hideo

    2013-01-01

    The production of stable isotope-labeled proteins is critical in structural analyses of large molecular weight proteins using NMR. Although prokaryotic expression systems using Escherichia coli have been widely used for this purpose, yeast strains have also been useful for the expression of functional eukaryotic proteins. Recently, we reported a cost-effective stable isotope-labeled protein expression using the hemiascomycete yeast Kluyveromyces lactis (K. lactis), which allow us to express exogenous proteins at costs comparable to prokaryotic expression systems. Here, we report the successful production of highly deuterated (>90 %) protein in the K. lactis system. We also examined the methyl-selective 1 H, 13 C-labeling of Ile, Leu, and Val residues using commonly used amino acid precursors. The efficiency of 1 H- 13 C-incorporation varied significantly based on the amino acid. Although a high level of 1 H- 13 C-incorporation was observed for the Ile δ1 position, 1 H, 13 C-labeling rates of Val and Leu methyl groups were limited due to the mitochondrial localization of enzymes involved in amino acid biosynthesis and the lack of transporters for α-ketoisovalerate in the mitochondrial membrane. In line with this notion, the co-expression with branched-chain-amino-acid aminotransferase in the cytosol significantly improved the incorporation rates of amino acid precursors. Although it would be less cost-effective, addition of 13 C-labeled valine can circumvent problems associated with precursors and achieve high level 1 H, 13 C-labeling of Val and Leu. Taken together, the K. lactis system would be a good alternative for expressing large eukaryotic proteins that need deuteration and/or the methyl-selective 1 H, 13 C-labeling for the sensitive detection of NMR resonances

  7. Inhibitor efficiency in long-time protection of steel tanks for the chemical surface preparation against local corrosion by process solutions containing hydrochloric acid; Inhibitorwirksamkeit beim Langzeitschutz von Stahlbehaeltern fuer die chemische Oberflaechenvorbereitung gegen oertliche Korrosion durch salzsaeurehaltige Prozessloesungen

    Energy Technology Data Exchange (ETDEWEB)

    Stieglitz, U.; Schulz, W.D. [Institut fuer Korrosionsschutz Dresden GmbH, Gostritzer Str. 61-63, D-01217 Dresden (Germany)

    2004-02-01

    The efficiency of prevailing acid inhibitors is examined by age hardening heavy tank-steel plates in technically usual hot-galvanizing solutions for 1000 hours. With acid inhibitors local corrosion emerged as shallow pit formation first and foremost in hydrochlorid acid pickles (20 g/l HCl) at ambient temperature as well as in cleaners containing hydrochloric acid (10-30 g/l HCl) at 40 C when other conditions also applied. Above all, local corrosion was produced if the inhibitor concentration became too low (0.2 g/l) in connection with a minimum hydrochloric acid concentration (10-30 g/l). However, oxidizing agents like iron(III)-ions (5-10 g/l), atmospheric oxygen and free chlorine (100-1000 mg/l) lead to local corrosion, too. Local corrosion did not emerge in rinse baths (2-10 g/l HCl) and fluxing material solutions of zinc chloride and ammonium chloride (pH value: 2.0-5.5). Here uniform corrosion developed. Acid inhibitors turned out to be very effective against uniform corrosion in the examined long-time period (inhibiting values up to 99%). (Abstract Copyright [2004], Wiley Periodicals, Inc.) [German] Die Wirksamkeit handelsueblicher Saeureinhibitoren wird durch eine Auslagerung von Grobblechen aus Behaelterstahl ueber 1000 Stunden in technisch gebraeuchlichen Loesungen der Feuerverzinkung untersucht. Oertliche Korrosion ist als Muldenkorrosion in Gegenwart von Saeureinhibitoren vor allem in Salzsaeurebeizen (20 g/l HCl) bei Raumtemperatur und in salzsaeurehaltigen Reinigern (10-30 g/l HCl) bei 40 C aufgetreten, wenn Zusatzbedingungen erfuellt sind. Oertliche Korrosion wird vorwiegend durch eine Unterschreitung der Inhibitorkonzentration (0,2 g/l) in Verbindung mit einer minimalen Salzsaeurekonzentration (10-30 g/l) ausgeloest. Aber auch Oxidationsmittel wie Eisen(III)-Ionen (5-10 g/l), Luftsauerstoff und freies Chlor (100-1000 mg/l) fuehren zu oertlicher Korrosion. In Spuelbaedern (2-10 g/l HCl) und Flussmittelloesungen aus Zinkchlorid und Ammoniumchlorid (p

  8. Wear characterization of a tool steel surface modified by melting and gaseous alloying

    International Nuclear Information System (INIS)

    Rizvi, S.A.

    1999-01-01

    Hot forging dies are subjected to laborious service conditions and so there is a need to explore means of improving die life to increase productivity and quality of forgings. Surface modification in order to produce wear resistant surface is an attractive method as it precludes the need to use expensive and highly alloyed steels. In this study, a novel, inexpensive surface modification technique is used to improve the tri biological properties of an H13 tool steel. Surface melting was achieved using a tungsten heat source and gaseous alloying produced under a shield of argon, carbon dioxide, carbon dioxide-argon mixture and nitrogen gases. The change in wear behaviour was compared through micro-hardness indentation measurements and using a dry sliding pin-on-plate wear testing machine. This study shows superior wear behaviour of the modified surfaces when compared to the untreated surfaces. The increase in wear resistance is attributed to the formation of carbides when surfaces are melted under a carbon dioxide shield. However, in the case of nitrogen and argon gaseous alloying, an increase in wear resistance can be attributed to an increase in surface hardness which in turn effects surface deformation behaviour. (author)

  9. Die vrede van Münster / Westfale en die betekenis daarvan vir die ...

    African Journals Online (AJOL)

    In die Suid-Afrikaanse kerkgeskiedenis egter is die Vrede van Münster as epogmakende gebeure tot dusver nie net in die algemeen verwaarloos nie, maar boonop is die direkte verband tussen hierdie sentrale historiese baken aan die een kant en aan die ander kant die vestiging van die VOC se verversingspos aan die ...

  10. Tegnologie en die mens

    African Journals Online (AJOL)

    omgewingsbesoedeling, volgend op industrialisasie en verstedeliking, gee uit- ing tot krete van wanhoop en frustrasie. Die maatskaplike ontwrigting agv outomatisasie het die begrippe van vervreemding en naam- loosheid op die voorgrond van sosiale be- wustheid geplaas. • Die Neutrale Siening. Tegnologie was nag. 34.

  11. GODSBEELDE IN DIE LITURGIE

    African Journals Online (AJOL)

    15 Mei 2010 ... Biezeveld, de Boer, Brümmer, Muis. 2001; Brown 2006; Durand 2007). ... Wanneer sal hy weer in God se teenwoordigheid verskyn (vers 3)? Dié vraag is vol onsekerheid. (Schuman 2004:8). Sy onsekerheid ... God se volk en die enkeling in die geskiedenis het al die trou van God ervaar waarop die digter ...

  12. Die ontwikkeling van die bestuursmotiveringsvraelys (BMV

    Directory of Open Access Journals (Sweden)

    A. S. Engelbrecht

    1991-06-01

    Full Text Available The development of the Managerial Motivation Questionnaire (MMQ: Several criticisms of the psychometric suitability of existing measures of managerial motivation are reported in the literature. This study aimed at developing a new psychometrically sound instrument, the Managerial Motivation Questionnaire (MMQ. This was done on the basis of a comprehensive study of the literature on managerial motivation and the role-motivation theory. The preliminary MMQ was systematically shortened and refined until the final MMQ of 98 items was composed. This was based on social desirability and semantic appraisal, item analysis and factor analysis of the questionnaire. The results indicate that it was possible to develop a final MMQ that was relatively free of social desirability. It further demonstrated satsifactory internal consistencies on two samples (a = 0/90, N = 360; a = 0/91, N = 535, where all subscale items were found to be relatively pure measures of the isolated factors. Although some evidence was found providing support for the reliability of the MMQ, a need for further research on the construct validity of managerial motivation still exists. Opsomming In die literatuur word verskeie punte van kritiek teen die psigometriese geskiktheid van bestaande meetinstrumente van bestuursmotivering gerapporteer. Die doelstelling van hierdie studie was dus om aan die hand van die konseptuele omiyning van bestuursmotivering, en die rolmotiveringsteorie as algemene verwysingsraamwerk, 'n nuwe psigometries aanvaarbare meetinstrument, die Bestuursmotiveringsvraelys (BMV, te ontwikkel. Op grond van sosiale wenslikheids- en semantiese beoordeling, itemontleding en faktorontleding van die voorlopige BMV is die vraelys stelselmatig verkort en verfyn totdat die finale BMV van 98 items saamgestel is. Die resultate dui daarop dat hierdie studie wel daarin geslaag het om 'n finale BMV te ontwikkel wat relatief vry van sosiale wenslikheid is, bevredigende interne

  13. Varswateralge en die ekonomie

    Directory of Open Access Journals (Sweden)

    W. E. Scott

    1988-03-01

    Full Text Available Die artikel bespreek die ekonomiese belong wat varswateralge alreeds het en hul moontlike verdere ontginning in die toekoms. Sowel gewenste as ongewenste aspekte word oorweeg en hoofsaaklik met voorbeelde uit Suid-Afrika geïllustreer. Die oormatige ontwikkeling van ongewenste alge in varswater verlaag die watergehalte dear verskeie chemiese veranderinge, wat kan wissel van smake en geure tot die produksie van verbindings wat gesondheidsgevare vir mens of dier inhou. Verwydering van ongewenste alge dra aansienlik by tot die koste van waterbehandeling. Oormatige alggroei belemmer ontspanningsgebruike en kan eiendomswaardes langs rivier- en damoewers beïnvloed.

  14. Prediking aan die hand van die metafoor van fiksieskryf

    African Journals Online (AJOL)

    p1243322

    HTS 64(3) 2008 siening van die self en waarheid. In die pre-moderne paradigma kan die dominante metafoor verstaan word aan die hand van 'n spieël wat die lig uit 'n transendente oorsprong weerkaats, terwyl die moderne paradigma uitgedruk word met die metafoor van 'n lamp wat 'n eie, oorspronklike lig binne die self.

  15. e .Kuraioriufn. DIE W ETENSKAPLIKE BETEKENIS VAN DIE W ERK

    African Journals Online (AJOL)

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    ENGELBRECHT ver antwoordelik vir die Ou-Testamentiese vakke en Hebreeus. Die aan stelling van 'n derde professor het noodsaaklik geword, want dit sou. 85 .... De .Spreuken ran 5a/o?no omvat die nuwe vertaling en die ekse gese van die eerste 24 hoofstukke van die Spreukeboek. Die geskoold- heid in die Semitiese ...

  16. Die dialogiese prinsipe

    Directory of Open Access Journals (Sweden)

    J. J. de Klerk

    1981-08-01

    Full Text Available Met die dialogiese prinsipe word daardie beginsel bedoel, waarin die tweerigtingverkeer of kommunikasie onder, of met, of deur die mense op 'n heel besondere gesprekmatige wyse gere�l word. Tot die wese van die dialogiese prinsipe behoort "als Grundvoraussetzung das Ernstnehmen des Gesprachspartners und das darin enthaltene zuhoren-konnen. Dialog ist also etwas anderes als Disput oder Diskussion. Er setzt gegenseitiges Vertrauen und Hochachtung voraus."

  17. Die sestienpersoonlikheidsfaktorvraelys as hulpmiddel by die takseersentrum

    Directory of Open Access Journals (Sweden)

    J. C. D. Augustyn

    1988-05-01

    Full Text Available The 16PF Personality Test as an aid to the assessment centre Assessment centres still remains costly and thime consuming. This study investigates the reduction of time and costs by the use of the 16 PF Personality Test as a method for measuring management dimensions. Promising results were obtained with a relatively small sample for the prediction of initiative and perseverance. Significant multiple correlations were also found for three criteria of management success. Further research may establish the use of the 16 PF as an aid to management assessment and thereby reduce the costs and time involved in assessment centres. Opsomming Takseersentrums se grootste probleem is gelee in die koste en tyd wat dit behels. Hierdie studie ondersoek die moontlikheid om beide te verminder deur die aanwending van die 16 PF Persoonlikheidsvraelys vir die meting van bestuursdimensies. Belowende resultate is met 'n relatiewe klein steekproef bevind ten opsigte van die voorspelling van inisiatiefen deursettingsvermoe. Beduidende meervoudige korrelasies is ook ten opsigte van drie kriteria van bestuursukses bevind. Verdere navorsing kan die gebruik van die 16 PF as hulpmiddel by bestuursevaluering vestig en sodoende die tydsduur en koste van takseersentrums verminder.

  18. DIE GESKIEDENIS VAN AFDELING LOGISTIEK

    African Journals Online (AJOL)

    1 Aug 1978 ... dan ook aangebied, Agv die probleem wat ont- staan het met die gebrek aan goedgekeurde poste vir die Afdeling en as gevolg van die ver- wagte vertraging met die ondersoek van die. DOS-span, het die Afdeling Logistiek en Afde- ling Personeel oorleg gepleeg en laasgenoemde het ingestem dat die ...

  19. Challenges in Special Steel Making

    Science.gov (United States)

    Balachandran, G.

    2018-02-01

    Special bar quality [SBQ] is a long steel product where an assured quality is delivered by the steel mill to its customer. The bars have enhanced tolerance to higher stress application and it is demanded for specialised component making. The SBQ bars are sought for component making processing units such as closed die hot forging, hot extrusion, cold forging, machining, heat treatment, welding operations. The final component quality of the secondary processing units depends on the quality maintained at the steel maker end along with quality maintained at the fabricator end. Thus, quality control is ensured at every unit process stages. The various market segments catered to by SBQ steel segment is ever growing and is reviewed. Steel mills need adequate infrastructure and technological capability to make these higher quality steels. Some of the critical stages of processing SBQ and the critical quality maintenance parameters at the steel mill in the manufacture has been brought out.

  20. Die relevansie van die boek Prediker

    African Journals Online (AJOL)

    ook in die dogmatiek te bespeur is nie. 'n Vinnige oorsig oor die teksverwysings van. 'n paar wydgelese dogmatiekhandboeke kan dit bevestig. In Karl Barth se omvang- ryke Kirchliche Dogmatik word Prediker slegs vyf en dertig maal aangehaal en slegs sewe maal word teksgedeeltes bespreek. Emil Brunner haal Prediker ...

  1. P. J. N. Smal, Die Universalisme in die Psalms. Academisch ...

    African Journals Online (AJOL)

    Test

    dat die historiese element in Israel se Godsopenbaring en daarmee die insig in sy betekenis te kort gedoen word. Die betekenis van die studie vir die historia revelationis is daardeur gering; as duidelike „tydlose” sistematisering van Outestamentiese gegewens oor die betrokke onder- werpe, soos die laaste hoofstuk, bl.

  2. DIE ONTVC'ERP VAN 'N SENDINGBELEID IN DIE HUIDIGE ...

    African Journals Online (AJOL)

    Test

    DIE ONTVC'ERP VAN 'N SENDINGBELEID IN DIE. HUIDIGE SITUASIE. Sending is 'n deel van die vervulling van die apostoliese opdrag van die kerk. Dit geskied op grond van en in gehoorsaamheid aan Gods. \\C'oord. Teologiese besinning is daarom die eerste en grondliggende vereiste by die ontwerp van 'n ...

  3. DIE PLEK VAN SANG EN MUSIEK IN DIE PROTESTANTSE ...

    African Journals Online (AJOL)

    Test

    Sy moet hierdie opdrag uitvoer deur mid del van die Prediking d.w.s. deur middel van die Woord-vorm, maar ook deur die bediening van die sakramente, dws. deur middel van die vorm van die Daad. Maar nou wil God nie hê dat die Kerk slegs één maal die Evangelie sal predik en die mense sal doop om hulle daarna.

  4. Packaged die heater

    Science.gov (United States)

    Spielberger, Richard; Ohme, Bruce Walker; Jensen, Ronald J.

    2011-06-21

    A heater for heating packaged die for burn-in and heat testing is described. The heater may be a ceramic-type heater with a metal filament. The heater may be incorporated into the integrated circuit package as an additional ceramic layer of the package, or may be an external heater placed in contact with the package to heat the die. Many different types of integrated circuit packages may be accommodated. The method provides increased energy efficiency for heating the die while reducing temperature stresses on testing equipment. The method allows the use of multiple heaters to heat die to different temperatures. Faulty die may be heated to weaken die attach material to facilitate removal of the die. The heater filament or a separate temperature thermistor located in the package may be used to accurately measure die temperature.

  5. Die radio in Afrika

    Directory of Open Access Journals (Sweden)

    S. de Villiers

    1966-03-01

    Full Text Available Omvang van radio-uitsendings in en na Afrika. — Redes vir die versnelde tempo van uitbreiding. — Radio as die geskikste massa-kommunikasiemiddel vir Afrika. — Faktore wat die verspreiding bemoeilik. — Skouspelagtige toename in luistertalle.Toe Plinius, wat in die jaar 79 oorlede is, in sy „Historia Naturalis” verklaar het dat daar altyd iets nuuts uit Afrika afkomstig is, kon hy nouliks voorsien het dat die „iets" negentien eeue later in die lug sou setel wat hierdie reuse-vasteland oorspan — ’n Babelse spraakverwarring en ’n ongekende, verbete woorde-oorlog in die etergolwe, onder meer daarop bereken om die harte en hoofde van derduisendes te verower.

  6. Die Erfindung des Manuskripts

    DEFF Research Database (Denmark)

    Benne, Christian

    Die Entstehung der literarischen Moderne ging seit dem 18. Jahrhundert damit einher, dass die Anzahl literarischer Manuskripte ebenso wuchs wie deren Bedeutung. Der Buchdruck hatte die Handschrift keineswegs überflüssig gemacht, sondern provozierte im Gegenteil einen neuen, am Autographen...

  7. Die begrafnisdíens

    African Journals Online (AJOL)

    Num 20: 1; Jos 24: 30; Hand 5: 5 - 11). Selfs van die ... Gebruike rondom die begrafnis het van geslag tot geslag gewissel. De Vaux ... der geskied deur die hoorders 'te onderrig, te vermaan, te vertroos en te bestraf, soos dit in elke geval ..... gehandhaaf hoef te word, veral in die lig van die feit dat die predikant die kerklike.

  8. Die gebruik van parallelplaatreologie vir die bepaling van die intrinsieke viskositeit van poli-etileentereftalaat

    Directory of Open Access Journals (Sweden)

    O. C. Vorster

    2005-09-01

    Full Text Available Die bepaling van die intrinsieke viskositeit van poli-etileentereftalaat word bemoeilik deur die feit dat daar tans slegs twee metodes in gebruik is. In die eerste metode word die bepaling deur middel van oplossingsviskometrie gedoen, maar die toksisiteit van die oplosmiddel, asook die tydperk wat dit neem om die bepaling te doen, is ’n probleem. Die tweede metode word beperk deur die kompleksiteit en beskikbaarheid van die apparatuur in Suid-Afrika. In hierdie studie word ’n alternatiewe metode, gebaseer op parallelplaatreologie, voorgestel wat albei hierdie probleme oorkom en die resultate sodoende verkry, word vergelyk met dié wat met bestaande metodes verkry is.

  9. Die invloed van die neo-marxistiese kultuuranalise op die Wêreldraad van Kerke en die Gereformeerde Kerke van Nederland

    Directory of Open Access Journals (Sweden)

    J. M. Vorster

    1979-05-01

    Full Text Available Toe die studente dwarsoor die VSA en Europa in die laat sestigerjare ’n plotselinge en radikale verset openbaar het teen die bestaande orde, het hulle die deur geopen vir ’n nuwe mededinger om die hart van die Westerse kultuur. Dit is die nou reeds bekende neo-Marxisme. Sedertdien het hierdie jongeling sy voetspore op vele vlakke van die Westerse kultuur gelaat.

  10. Multi criteria decision making of machining parameters for Die Sinking EDM Process

    Directory of Open Access Journals (Sweden)

    G. K. Bose

    2015-04-01

    Full Text Available Electrical Discharge Machining (EDM is one of the most basic non-conventional machining processes for production of complex geometries and process of hard materials, which are difficult to machine by conventional process. It is capable of machining geometrically complex or hard material components, that are precise and difficult-to-machine such as heat-treated tool steels, composites, super alloys, ceramics, carbides, heat resistant steels etc. The present study is focusing on the die sinking electric discharge machining (EDM of AISI H 13, W.-Nr. 1.2344 Grade: Ovar Supreme for finding out the effect of machining parameters such as discharge current (GI, pulse on time (POT, pulse off time (POF and spark gap (SG on performance response like Material removal rate (MRR, Surface Roughness (Ra & Overcut (OC using Square-shaped Cu tool with Lateral flushing. A well-designed experimental scheme is used to reduce the total number of experiments. Parts of the experiment are conducted with the L9 orthogonal array based on the Taguchi methodology and significant process parameters are identified using Analysis of Variance (ANOVA. It is found that MRR is affected by gap current & Ra is affected by pulse on time. Moreover, the signal-to-noise ratios associated with the observed values in the experiments are determined by which factor is most affected by the responses of MRR, Ra and OC. These experimental data are further investigated using Grey Relational Analysis to optimize multiple performances in which different levels combination of the factors are ranked based on grey relational grade. The analysis reveals that substantial improvement in machining performance takes place following this technique.

  11. Results obtained so far with the production of turbine and valve casings made of the new 9% Cr cast steel types G-X 12 CrMoWVNbN 10 11 and G-X 12 CrMoVNbN 91; Erfahrungsbericht ueber die Herstellung von Turbinen- und Ventilgehaeusen aus den neuen 9% Cr-Stahlgusssorten G-X 12 CrMoWVNbN 10 1 1 und G-X 12 CrMoVNbN 91

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, F.; Buberl, A.; Hanus, R. [VOEST-ALPINE STAHL LINZ GmbH, Linz (Austria); Cerjak, H. [Technische Univ., Graz (Austria)

    1996-12-31

    In the course of production start-up of new 9-10% Cr cast steel types, and application of R and D results to practice, the following examinations and modifications have been performed: 1. Reduction of average chromium content from 10.5 to 9.5% in order to suppress delta ferrite segregation, and adjustment of austenite and ferrite stabilizing alloying constituents. 2. Analysis of typical defects in castings, and modification of casting and feeding techniques in compliance with the saturation behaviour of the new 9-10% Cr steels. These measures achieved a reduction of feeding-based flaws (shrinkage) in the last few cast pieces. 3. The good weldability was proven of the new 9-10% Cr steels by means of welding tests and crack-free production and construction welds made in cast pieces. (orig./MM) [Deutsch] Im Zuge der Produktionsaufnahme neuer 9-10% Cr-Stahlgusssorten und der Ueberleitung der F and E Ergebnisse in die betriebliche Praxis wurden folgende Untersuchungen und Anpassungen vorgenommen: 1. Um die Deltaferritausscheidung zu unterdruecken, wurde der mittlere Chromgehalt von 10,5 auf 9,5% abgesenkt und die austenit- und ferritstabilisierenden Legierungselemente besser angepasst. 2. Die Analyse typischer Fehlererscheinungen an Gussstuecken machten eine Anpassung der Giess- und Speisungstechnik an das Saettigungsverhalten der neuen 9-10% Cr-Staehle erforderlich. Diese Massnahmen fuehrten zu einer Verringerung der Speisungsfehler (Lunker) bei den zuletzt abgegossenen Gussstuecken. 3. Bei Schweissversuchen und an Gussstuecken rissfrei ausgefuehrten Fertigungs- und Konstruktionsschweissungen konnte die gute Schweisseignung der neuen 9-10% Cr-Staehle nachgewiesen werden. (orig./MM)

  12. die pers as bron oor die geskiedenis van die eerste vrydeidsoorlog

    African Journals Online (AJOL)

    dood agv wonde wat hy tydens die slag opgedoen het. Dit was vir die Britse volk onaanvaarbaar dat slegs twee Boere gedood is nadat daar tussen. 20 000 en 30 000 rondtes op die Boere afgevuur is. Die pers kon net nie die ware syfers publiseer nie, want dit sou na 'n onwaarheid Iyk. Het die. Britse volk egter die Boere ...

  13. die impak van metodologie op die verstaan van die nuwe testament

    African Journals Online (AJOL)

    voorbeeld eers een maal deur die bril van die vorm- en redaksiekritiek na die Evangelies gekyk het, dink jy vir altyd anders oor hulle tot- standkoming. Inderdaad, nuwe metodes lei tot nuwe perspektiewe! Dit is dan ook waar die fokus van hierdie artikel val: die impak van metodologie op die verstaan van die Nuwe ...

  14. Verskuiwing in die moraal?

    Directory of Open Access Journals (Sweden)

    S.P. van der Walt

    1974-03-01

    Full Text Available Modewoorde het ons deesdae oorgenoeg in die Christelike sedeleer en hulle kan nogal verwarring stig. U moet my vergun om met u te spreek oor een so ’n modewoord nl „verskuiwing’’ in die moraal. Dis nogal ’n mooi woord, wat so dikwels gebruik word op baie terreine en tog meer wil aandui as maar net ’n veranderde sienswyse, ’n wysiging in opvattinge of nuwe riglyne wat al gangbaar geword het in die praktyk. Die begrip wil eintlik die ewolusionêre gang beklemtoon, want dit is dan eintlik net die ou norme wat effens anders bekyk word of nie meer so nou geneem of dik onderstreep word nie. Die verskuiwing beteken dan dat alles nog dieselfde bly, net die posisie of plek het verander. Verskuiwing beteken tog plekverandering of plekwisseling en dan sekerlik nie in die sin dat die plekke ver uitmekaar lê nie. Verskuiwing beteken net maar vlak langs die vorige te staan kom. As dit dan ’n beter plek is, is dit ewolusie, ontwikkeling, verbetering.

  15. Wear of Shaped Surfaces of PVD Coated Dies for Clinching

    Directory of Open Access Journals (Sweden)

    Miroslav Džupon

    2017-11-01

    Full Text Available A clinching method that uses a simple toolset consisting of a punch and a die, is utilized for joining lightweight materials. This paper is aimed at investigating the wear of the die cavity of a clinching tool. A clinching tool with a specially shaped cavity was used for joining thin hot-dip galvanized steel sheets. Various types of physical vapour deposition (PVD coatings such as ZrN, CrN and TiCN were deposited on the shaped surface of the die using Lateral Rotating Arc-Cathodes technology. Hot-dip galvanized steel sheets were used for testing the clinching tool. The material properties of PVD coatings that were deposited on the shaped part of the clinching die were evaluated. Finite Element Analysis was used to localize the area of the shaped part of the die and the part of surface area of the cylindrical die cavity of ϕ 5.0 mm, in which high contact pressure values were predicted. The prediction of the start of the wear cycle was verified experimentally by the clinching of 300 samples of hot-dip galvanized steel sheets. Unlike the CrN and ZrN coatings, the TiCN coating remained intact on the entire surface of the die.

  16. oor die inhoud en boodskap van die heidelbergse kategismus

    African Journals Online (AJOL)

    Smit. Oor die Inhoud en Boodskap van die Heidelbergse Kategismus. 52. Uiteraard sal dié tema saamhang met die bedoelinge agter die opstel van die Kategismus. Ook die vraag na moontlike bedoelinge of motiewe is egter 'n ingewikkelder vraag as wat miskien gedink mag word. Uiteraard was daar agter elke kategismus ...

  17. Thomas Erastus oor die struktuur van die gemeenskap'^

    African Journals Online (AJOL)

    óók aansprake en regte het, is die opvatting dat sowel die burgerlike gemeenskap as die kerk 'n perfecta societas sibi sufficiens is, nié werklik aanvaar nie. Die Middeleeuse gemeenskap was die corpus christianum,. 'n gemeenskap wat nie deur fisiese of politieke grense beperk was nie. Sy grense het gelê waar die grense ...

  18. die doel en wese van opvoedende onderwys en die implikasies

    African Journals Online (AJOL)

    Oaar moet onderskei word tussen die doelstellings van opvoedende onderwys en die einddoel wat bereik word deur die nastrewing van hierdie doelstellings. Gunter praat van die naderliggende doelstellings (1981, b1.105). \\/at die enddoel van opvoedende onderwys bet ref, gaan die meeste opvoedkundi ges akkoord dat ...

  19. Effect of the Die Temperature and Blank Thickness on the Formability of a Laser-Welded Blank of a Boron Steel Sheet with Removing Al-Si Coating Layer

    Directory of Open Access Journals (Sweden)

    M. S. Lee

    2014-05-01

    Full Text Available Reducing carbon emissions has been a major focus in the automobile industry to address various environmental issues. In particular, studies on parts comprised of high strength sheets and light car bodies are ongoing. Accordingly, this study examined the use of boron steel, which is commonly used in high strength sheets. Boron steel is a type of sheet used for hot stamping parts. Although it has high strength, the elongation is inferior, which reduces its crash energy absorption capacity. To solve this problem, two sheets of different thickness were welded so the thin sheet would absorb crash energy and the thick sheet would work as a support. Boron steel, however, may show weakening at the welding spot due to the Al-Si coating layer used to prevent oxidation from occurring during the welding process. Therefore, a certain part of the coating layer of a double-thickness boron steel sheet that is welded in the hot stamping process is removed through laser ablation, and the formability of the hot-work was examined.

  20. İKİ FARKLI SIVI ORTAMDA NİTRÜRLENMİŞ H13 ÇELİĞİNİN AŞINMA DAVRANIŞI

    Directory of Open Access Journals (Sweden)

    HATEM AKBULUT

    2005-01-01

    Full Text Available Bu çalışmada, H13 sıcak iş takım çeliği ve bu çelikierin yüzey lerinin sertleştirilmesi amacıyla kullanılan prosesler hakkında bilgi verilmiş; ekonomik, yararlı ve basit bir termokimyasal yöntenı olan sıvı tuz ortamında nitrürleme prosesi üzerinde durulmuştur. Sanayide kullanılan sıvı nitrürleme proseslerinden Su rsuJf Prosesi ve Tufftride Prosesi ile 570 oc ve 550 °C'de 2 ve 2,5 saat nitrürlenen H13 (DlN 1.2344 çelik numuneler üzerinde metalografik incelemeler., sertlik testleri, aşınma testleri ve XRD faz analizleri yapılm•ş ve hangi prosesin ne şekilde uygulandığında çelik yüzeyinin maksimum aşınma direnci gösterdiği belirlenmeye çalışılmıştır. Sonuç olarak Tufftride Prosesi ile 570 °C'de 2,5 saat b o y unca nitrürlenen numuneden maksimum yüzey sertliği (1086 HVN ve maksimum beyaz tabaka (15 JJ.m ve difüzyon tabakası (195 JJ.. m kalınlıkları elde edilmiştir. Anahtar Kelime/er- Sursulf, Tufftride, nitrürleme. Abstract - In this study, s ome info rmation is given about Hl3 hot working tool steel and processes used for surface hardening of these steels; salt batb nitriding process which is an econo mical and effective thermochemical nitriding process is studied. H13 (DI N 1.2344 saınples are nitrided for 2 and 2,5 hours at 550 oc and 570 oc by Tufftride and Sursulf Process which are salt bath nitriding proc esses and used in indu � try. Hardness tests, XRD phase analyses, wearıng tests and metallographic examination are applied on nitrided samples. As a result, maximum surface hardness (1086 HVN and maximum white layer thickness (15 J.Lm and diffusion zone thickness (195 ıım are obtained from the sample whicb is nitrided by Tufftride for 2,5 hours at 570 oc. Keywords - Sursulf, Tufftride, nitriding. H. AKBULUT, E. BENGÜ, Sakarya Üniv. Fen Bil. Enst. Met. ve Malz. Müh. Bölümü, SAKARYA I. GİRİŞ Günümüzde demir esaslı malzemelerin yüzeylere: korozyon, darbe, a

  1. Benchmark fragment-based 1H, 13C, 15N and 17O chemical shift predictions in molecular crystals†

    Science.gov (United States)

    Hartman, Joshua D.; Kudla, Ryan A.; Day, Graeme M.; Mueller, Leonard J.; Beran, Gregory J. O.

    2016-01-01

    The performance of fragment-based ab initio 1H, 13C, 15N and 17O chemical shift predictions is assessed against experimental NMR chemical shift data in four benchmark sets of molecular crystals. Employing a variety of commonly used density functionals (PBE0, B3LYP, TPSSh, OPBE, PBE, TPSS), we explore the relative performance of cluster, two-body fragment, and combined cluster/fragment models. The hybrid density functionals (PBE0, B3LYP and TPSSh) generally out-perform their generalized gradient approximation (GGA)-based counterparts. 1H, 13C, 15N, and 17O isotropic chemical shifts can be predicted with root-mean-square errors of 0.3, 1.5, 4.2, and 9.8 ppm, respectively, using a computationally inexpensive electrostatically embedded two-body PBE0 fragment model. Oxygen chemical shieldings prove particularly sensitive to local many-body effects, and using a combined cluster/fragment model instead of the simple two-body fragment model decreases the root-mean-square errors to 7.6 ppm. These fragment-based model errors compare favorably with GIPAW PBE ones of 0.4, 2.2, 5.4, and 7.2 ppm for the same 1H, 13C, 15N, and 17O test sets. Using these benchmark calculations, a set of recommended linear regression parameters for mapping between calculated chemical shieldings and observed chemical shifts are provided and their robustness assessed using statistical cross-validation. We demonstrate the utility of these approaches and the reported scaling parameters on applications to 9-tertbutyl anthracene, several histidine co-crystals, benzoic acid and the C-nitrosoarene SnCl2(CH3)2(NODMA)2. PMID:27431490

  2. Benchmark fragment-based (1)H, (13)C, (15)N and (17)O chemical shift predictions in molecular crystals.

    Science.gov (United States)

    Hartman, Joshua D; Kudla, Ryan A; Day, Graeme M; Mueller, Leonard J; Beran, Gregory J O

    2016-08-21

    The performance of fragment-based ab initio(1)H, (13)C, (15)N and (17)O chemical shift predictions is assessed against experimental NMR chemical shift data in four benchmark sets of molecular crystals. Employing a variety of commonly used density functionals (PBE0, B3LYP, TPSSh, OPBE, PBE, TPSS), we explore the relative performance of cluster, two-body fragment, and combined cluster/fragment models. The hybrid density functionals (PBE0, B3LYP and TPSSh) generally out-perform their generalized gradient approximation (GGA)-based counterparts. (1)H, (13)C, (15)N, and (17)O isotropic chemical shifts can be predicted with root-mean-square errors of 0.3, 1.5, 4.2, and 9.8 ppm, respectively, using a computationally inexpensive electrostatically embedded two-body PBE0 fragment model. Oxygen chemical shieldings prove particularly sensitive to local many-body effects, and using a combined cluster/fragment model instead of the simple two-body fragment model decreases the root-mean-square errors to 7.6 ppm. These fragment-based model errors compare favorably with GIPAW PBE ones of 0.4, 2.2, 5.4, and 7.2 ppm for the same (1)H, (13)C, (15)N, and (17)O test sets. Using these benchmark calculations, a set of recommended linear regression parameters for mapping between calculated chemical shieldings and observed chemical shifts are provided and their robustness assessed using statistical cross-validation. We demonstrate the utility of these approaches and the reported scaling parameters on applications to 9-tert-butyl anthracene, several histidine co-crystals, benzoic acid and the C-nitrosoarene SnCl2(CH3)2(NODMA)2.

  3. Die tug oor ampsdraers tydens die doleansie van 1886

    Directory of Open Access Journals (Sweden)

    J. Visser

    1986-06-01

    Full Text Available In art 29 van die Nederlandse Geloofsbelydenis word bely: “Die merktekens om die ware Kerk te ken is die volgende: As die Kerk die suiwere prediking van die evangelie uitoefen, as dit die suiwer bediening van die sakramente gebruik soos Christus dit ingestel het, as die kerklike tug gebruik word om die sondes te straf.” Dit spreek vanself dat wanneer ampsdraers, aan wie Christus sy kudde toevertrou het (Hand 20 : 28, met leer en /of lewenswandel in sonde volhard en nie daarin met tug gestuit word nie, word die ware kerk nie gebou nie maar afgebreek. 0ns sal later in hierdie artikel aantoon hoedanig die suiwer tug oor ampsdraers, veral leertug, tydens die Doleansie tot skade van die kerk van Christus agterweë gebly het.

  4. Die metafoor by Breyten Breytenbach

    African Journals Online (AJOL)

    Owner

    23 Jun 2009 ... metafories, of spesifiek verwysend, te werk gegaan is. Tyd sou mens die hoofmotief van die bundel noem, tyd en geheue wat verbygaan: 1 en 2; en die einde van die storie wat gekom het: “fluit-fluit my storie is uit”. (Die tema van verbygaan word weer opgeneem in 8 en 9: die stories wat nooit meer gehoor ...

  5. IRAN IN DIE INTERNASIONALE MAGSTRYD

    African Journals Online (AJOL)

    In die verband kan genoem word dat die Russe nog grotendeels gebruik maak van 'n metode waarvolgens water in die oliestratum gepomp word om 'n opwaartse druk van ru-olie te verseker; een nadeel hiervan is dat die water mettertyd deur die oliehoudende laag ontsnap en agv die drukverlies isvoortgesette ontginning.

  6. Die singulation method

    Science.gov (United States)

    Swiler, Thomas P.; Garcia, Ernest J.; Francis, Kathryn M.

    2013-06-11

    A method is disclosed for singulating die from a semiconductor substrate (e.g. a semiconductor-on-insulator substrate or a bulk silicon substrate) containing an oxide layer (e.g. silicon dioxide or a silicate glass) and one or more semiconductor layers (e.g. monocrystalline or polycrystalline silicon) located above the oxide layer. The method etches trenches through the substrate and through each semiconductor layer about the die being singulated, with the trenches being offset from each other around at least a part of the die so that the oxide layer between the trenches holds the substrate and die together. The trenches can be anisotropically etched using a Deep Reactive Ion Etching (DRIE) process. After the trenches are etched, the oxide layer between the trenches can be etched away with an HF etchant to singulate the die. A release fixture can be located near one side of the substrate to receive the singulated die.

  7. Ontsporing van die regstaatsbegrip en sy konsekwensies vir die afrikanervolk

    Directory of Open Access Journals (Sweden)

    N. G.S. Van der Walt

    1966-03-01

    Full Text Available Die opvatting van die suiwere regstaat bring sy vraagstukke mee wanneer dit in verband gebring word met die leer van die soewereiniteit in eie kring. Laasgenoemde leer wortel in die geloof dat God die mens roep tot diens aan Hom, en dat die mens vry moet wees om ten opsigte van alle lewensaspekte God na die hoogste mate te kan dien. Hierdie verskeidenheid van aspekte is deur dr. A. Kuyper en sy volgelinge gesistemati- seer tot menslike verbande en lewenskringe, elk met ’n be- paalde sfeer waarin ander kringe nie mag inmeng nie. Elkeen is dan soewerein binne sy eie kring. Met verwysing na die staat is dan gespreek van die staatstaak as synde die hand- hawing van die reg, en omdat die staat in toenemende mate hom veral in die latere tyd ook besig gehou het met bedrywig- hede wat nouliks as van juridiese aard beskou kan word, is daar die onderskeid gemaak tussen die primêre en sekundêre taak van die staat. Die sistematiek van die wetsidee, deur prof. Dooyeweerd ontwikkel, waar die staat sy bestemmingsfunksie in die regsaspek vind, het vanselfsprekend geen plek vir so 'n dualistiese staatstaak nie, en die oplossing is deur sommige daarin gesoek om sulke staatsoptrede te vertolk as hebbende wel betrekking op die regsgemeenskap of die regsverkeer. Staatsondernemings soos paaie, spoorweë, spellingreëling, ens. word dan beskou as noodsaaklik vir die instandhouding van die regsgemeenskap en regsverkeer. Tereg wys A. M. Donner1 daarop dat so ’n vertolking eintlik neerkom op ’n oorspanning van die regsbegrip. Hy self sien dan die staatstaak in vrede- of orde-handhawing, wat in die eerste plaas wel regshandha- wing veronderstel. Onder orde word dan alles verstaan wat noodsaaklik is vir die gladde verkeer in die ontwikkelingsgang van die regsgemeenskap. Die wese van die staat het dan vol- gens hom te doen met reg, maar sy taak is meer as suiwere regshandhawing. Wat onrus verwek en die orde versteur, moet uit die openbare lewe verwyder word, en die

  8. Die sterwende kindjie

    Directory of Open Access Journals (Sweden)

    J.T. De Jongh van Arkel

    1983-09-01

    Full Text Available The thought of a child dying appears as an antithesis and thus the feelings evoked by the dying child are stronger than when older persons are dying. Around the child’s death bed there is no place for detached spectators and all become involved in caring for and supporting him. Caregivers also have a supporting responsibility towards the members of the child’s family.

  9. Analise van die Tswanaraaisel

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    S. A. Swanepoel

    1984-05-01

    Full Text Available ’n Strukturele, stilistiese en funksionele bcskrywing van die Twanaraaisel bring mee dat daar aan die volgende aspekte aandag gegee moet word: •\tWat is ’n raaisel en lioe word dit in Tswana genoem. •\tTot watter studiegebied en literere genre hoort die raaisel en watter subvorme kan vir Tswana onderskei word. •\tHoe sien die struktuur van Tswanaraaisels daar uit. •\tDeur wie, waar, wanneer en hoe word Tswanaraaisels voorgedra. •\tWatter stilistiese kenmcrke kan in Tswanaraaisels onderskei word. •\tWatter funksies vervul raaisels in ’n Tswanagcmeenskap.

  10. The Angry Dying Patient.

    Science.gov (United States)

    Houston, Robert E.

    1999-02-01

    Over 25 years ago, Kubler-Ross identified anger as a predictable part of the dying process. When the dying patient becomes angry in the clinical setting, all types of communication become strained. Physicians can help the angry dying patient through this difficult time by using 10 rules of engagement. When physicians engage and empathize with these patients, they improve the patient's response to pain and they reduce patient suffering. When physicians educate patients on their normal responses to dying and enlist them in the process of family reconciliation, they can impact the end-of-life experience in a positive way.

  11. Die brein soos beskou deur die Grieke en Romeine

    Directory of Open Access Journals (Sweden)

    Francois P. Retief

    2015-02-01

    Full Text Available In Ou Egipte is mummifikasie met uitgebreide reseksie of uitsnyding van organe geassosieer, maar geen kennis is geneem van die morfologie van die brein nie. Griekse skrywers van die sesde en vyfde eeue v.C. het die brein aanvanklik gesien as die setel van intelligensie, die orgaan van sensoriese waarneming en gedeeltelik die oorsprong van sperma. Pneuma het ’n belangrike rol in breinfunksie gespeel. Hippokrates was die eerste om die brein te beskryf as ’n dubbele orgaan, wat met harsingvlies (meninges bedek, funksioneel van pneuma afhanklik en vertolker van begrip is. Tydgenote soos Plato, Aristoteles en Diokles het tot die beskrywing bygedra, maar laasgenoemde twee het beweer dat die hart die middelpunt van intelligensie is en nie die brein nie. Gedurende die laaste helfte van die vierde eeu v.C. is disseksie van die menslike liggaam tydelik aan die mediese skool van Alexandrië toegelaat en het dit tot merkwaardige vooruitgang in die begrip van die menslike anatomie en fisiologie gelei. Herofilus en Erasistratus het uitstekende beskrywings van die struktuur en funksie van die brein gegee wat eers in die tweede eeu n.C. deur Galenus geëwenaar is.

  12. Damascus steel ledeburite class

    Science.gov (United States)

    Sukhanov, D. A.; Arkhangelsky, L. B.; Plotnikova, N. V.

    2017-02-01

    Discovered that some of blades Damascus steel has an unusual nature of origin of the excess cementite, which different from the redundant phases of secondary cementite, cementite of ledeburite and primary cementite in iron-carbon alloys. It is revealed that the morphological features of separate particles of cementite in Damascus steels lies in the abnormal size of excess carbides having the shape of irregular prisms. Considered three hypotheses for the formation of excess cementite in the form of faceted prismatic of excess carbides. The first hypothesis is based on thermal fission of cementite of a few isolated grains. The second hypothesis is based on the process of fragmentation cementite during deformation to the separate the pieces. The third hypothesis is based on the transformation of metastable cementite in the stable of angular eutectic carbide. It is shown that the angular carbides are formed within the original metastable colony ledeburite, so they are called “eutectic carbide”. It is established that high-purity white cast iron is converted into of Damascus steel during isothermal soaking at the annealing. It was revealed that some of blades Damascus steel ledeburite class do not contain in its microstructure of crushed ledeburite. It is shown that the pattern of carbide heterogeneity of Damascus steel consists entirely of angular eutectic carbides. Believe that Damascus steel refers to non-heat-resistant steel of ledeburite class, which have similar structural characteristics with semi-heat-resistant die steel or heat-resistant high speed steel, differing from them only in the nature of excess carbide phase.

  13. Variable H13CO+ Emission in the IM Lup Disk: X-Ray Driven Time-dependent Chemistry?

    Science.gov (United States)

    Cleeves, L. Ilsedore; Bergin, Edwin A.; Öberg, Karin I.; Andrews, Sean; Wilner, David; Loomis, Ryan

    2017-07-01

    We report the first detection of a substantial brightening event in an isotopologue of a key molecular ion, HCO+, within a protoplanetary disk of a T Tauri star. The H13CO+ J=3-2 rotational transition was observed three times toward IM Lup between 2014 July and 2015 May with the Atacama Large Millimeter/submillimeter Array. The first two observations show similar spectrally integrated line and continuum fluxes, while the third observation shows a doubling in the disk-integrated J=3-2 line flux compared to the continuum, which does not change between the three epochs. We explore models of an X-ray active star irradiating the disk via stellar flares, and find that the optically thin H13CO+ emission variation can potentially be explained via X-ray-driven chemistry temporarily enhancing the HCO+ abundance in the upper layers of the disk atmosphere during large or prolonged flaring events. If the HCO+ enhancement is indeed caused by an X-ray flare, future observations should be able to spatially resolve these events and potentially enable us to watch the chemical aftermath of the high-energy stellar radiation propagating across the face of protoplanetary disks, providing a new pathway to explore ionization physics and chemistry, including electron density, in disks.

  14. DIE SUID-AFRIKAANSE JEUG IN VOORTREKKERTYDPERK

    African Journals Online (AJOL)

    dien. Die planke en velie moes keer dat die assegaaie die mense tref. Voor die geveg het die vrouens en groter dogters koeels gegiet. Tydens die geveg het die seuns gehelp skiet terwyl die vrouens en dogters die gewere vir die mans gelaai het. Van die dogters soos Nellie. Botha (11 jaar oud) en haar sussie Fya (15 jaar.

  15. Die uitbouing van die Bybelse kanon in antieke Judaïsme en die ...

    African Journals Online (AJOL)

    31 Jul 2015 ... die oer-Christelike boodskap tot by sy Ou Testamentiese wortels, die geskrifte van Israel wat cum grano salis die 'Bybel' van die oer-Christendom geword het en die blywende verwysingspunt van die Christelike boodskap is. Erkenning. Hierdie artikel is vertaal na Afrikaans deur Prof. Jan G. van der Watt.

  16. Die opleiding van bedryfsielkundiges aan die universiteit van Fort Hare

    Directory of Open Access Journals (Sweden)

    W. Botha

    1977-11-01

    Full Text Available Die Departement Bedryfsielkunde aan die Universiteit van Fort Hare is 'n relatiewe jong departement en het eers in 1965 tot stand gekom. Voor hierdie datum is Bedryfsielkunde as 'n kort kursus deur die departement van suiwer Sielkunde aangebied en een van die destydse dosente, Dr. W. Backer, het die inisiatief geneem om 'n selfstandige departement van Bedryfsielkunde in die Fakulteit van Ekonomiese Wetenskappe op die been te bring.

  17. Oor die Bybel in die Afrikaanse digkuns

    African Journals Online (AJOL)

    another. As a matter of fact, the development of Afri kaans, the instrument of the poet, has been significantly influenced the Afrikaans translation of the Bible. Belie ... ook gesê het: Saam met ons literatuur, so oud as hy is. Die eerste Afrikaanse digter by wie ons omvattende Bybelse invloed kry, is. Totius, een van ons vroegste ...

  18. calvyn oor die leiding van die heilige gees in die verklaring van die

    African Journals Online (AJOL)

    Mittel alters, bis er zur Ruhe kommt bei den kanonischen Schriften der. Urzeit der christlichen Ära (Barth ... (ego tamen dimoveri non possum ab amore compendii, CO 10, 403). Deur die boodskap van die .... Idem ergo spiritus qui per os prophetarum loquutus est, in corda nostra penetret necesse est, ut persuadeat fideliter ...

  19. KERKWEES IN DIE

    African Journals Online (AJOL)

    Acta Theologica is an accredited South. African journal publishing ... SciELO South Africa. REDAKSIE/ ... 'n persoon belydenis van geloof af wat instemming met die betrokke kerk se ...... Ek was na my ongeluk buite aksie en op Clarens. 'n Mede-lid ...... Die “formation of new confessions, change to current confessions, and.

  20. Dying with dignity

    OpenAIRE

    S P Kalantri

    2003-01-01

    The concept of dignity has beeen one of the ambiguous concepts in biomedical ethics. Thus the ambiguous nature of this concept has been extended to what it means to die with dignity. This research work is an investigation into the complexity in the understanding of "dying with dignity" in Applied Ethics.

  1. The day Madiba died

    African Journals Online (AJOL)

    8 Apr 2016 ... shibien en ma is nie happy nie. Susan Gaigher se allegoriese fanta- sie- oftewel wetenskapsfiksieverhale. “Martine se teepot” (46–55) en “Maslow”. (56–67) is verfrissend. Gaigher is een van die min skrywers in die bundel wat 'n kenmerkende en oorspronklike stem laat klink. 'n Mens sal 'n Gaigher-verhaal.

  2. Die entwicklung, die metamorphose, die entstehung: Die konzepte des organismus von Aristoteles bis Darwin

    Directory of Open Access Journals (Sweden)

    Kamerer Eva

    2009-01-01

    Full Text Available (nemački In diesem Aufsatz versuche ich, die Elemente verschiedener Konzepte des Organismus in der Philosophie und in der Wissenschaft zu analysieren. Die Deutungen des Organismus und der Einheit der Natur bei Aristoteles, Kant und Goethe werden als ein Beispiel der Bewegung von einem finalistischen zum antifinalistischen Bild der Natur verstanden.

  3. Paradigmas en progressie in die teologie: *n Perspektief op die ...

    African Journals Online (AJOL)

    Die metodologie as besinningsterrein word egter al belangriker. Gedurende die tweede week van April 1988 het teoloë van dwarsoor Suid-. Afrika by die nuwe gebou van die Raad vir Geesteswetenskaplike Navorsing in. Pretoria byeen gekom vir 'n kongres van amper drie dae met die tema Paradigma.'> 476. ISSN 0259 ...

  4. die korrelasie tussen die gemiddelde daaglikse toename van ...

    African Journals Online (AJOL)

    'n Regressielyn is uit die gegewens bereken deur 'n beswaarde regressieanaliese en die 80 persent-voorspellings- bande is bepaal. Die punte wat ver buite die normale ver- spreidingsband geval hetkon almal met goeie rede as abnor- maal beskou word (sien tabel 1) en is nie ingesluit by die statistiese berekenings nie.

  5. amp' van die ouderling in die Nuwe Testament

    African Journals Online (AJOL)

    Jesus self het geen kerk gestig nie en daarom, veral omdat die Jesus-beweging inter mums ten opsigte van die Joodse godsdiens van sy tyd tot stand gekom het, het ...... Die klem val dus nie op die npoTCTT0fievo<; se rang of outoriteit nie, maar op sy pastorale funksie in die huishouding of huisgemeente (kyk Reicke.

  6. 1H, 13C and 15N chemical shift assignments of the thioredoxin from the obligate anaerobe Desulfovibrio vulgaris Hildenborough.

    Science.gov (United States)

    Garcin, Edwige B; Bornet, Olivier; Pieulle, Laetitia; Guerlesquin, Françoise; Sebban-Kreuzer, Corinne

    2011-10-01

    Thioredoxins are ubiquitous key antioxidant enzymes which play an essential role in cell defense against oxidative stress. They maintain the redox homeostasis owing to the regulation of thiol-disulfide exchange. In the present paper, we report the full resonance assignments of (1)H, (13)C and (15)N atoms for the reduced and oxidized forms of Desulfovibrio vulgaris Hildenborough thioredoxin 1 (Trx1). 2D and 3D heteronuclear NMR experiments were performed using uniformly (15)N-, (13)C-labelled Trx1. Chemical shifts of 97% of the backbone and 90% of the side chain atoms were obtained for the oxidized and reduced form (BMRB deposits with accession number 17299 and 17300, respectively).

  7. Tool steel ion beam assisted nitrocarburization

    International Nuclear Information System (INIS)

    Zagonel, L.F.; Alvarez, F.

    2007-01-01

    The nitrocarburization of the AISI-H13 tool steel by ion beam assisted deposition is reported. In this technique, a carbon film is continuously deposited over the sample by the ion beam sputtering of a carbon target while a second ion source is used to bombard the sample with low energy nitrogen ions. The results show that the presence of carbon has an important impact on the crystalline and microstructural properties of the material without modification of the case depth

  8. Die toekoms en ons roeping

    Directory of Open Access Journals (Sweden)

    S. du Toit

    1954-03-01

    Full Text Available Om te weet wat ons roeping in die toekoms sal wees, moet ons eers besef wat in ons eie tyd aan die gang is en langs watter lyne die dinge beweeg. Dit is ons plig om te let op die tekens van die tye in die lig van die profetiese Woord. En dan wil ons dadelik beklemtoon dat ons in Suid-Afrika nie in die waan moet lewe dat ons hier onbekommerd en onaangetas deur die wêreldgebeure ons roeping en bestemming kan uitwerk nie.

  9. Die Hervormde Teologiese Studies na vyftig jaar

    African Journals Online (AJOL)

    INLEIDEND. In die tweede helfte van die jaar 1943 het die Hervormde Teologiese Studies die eerste maal verskyn. Dit was die produk van lang besinning en beplanning. Die dryfkrag agter die totstandkoming was prof dr S P Engeibrecht, 'n man wie se idealisme en toewyding aan die kerk groot dinge vir die kerk en ook die ...

  10. Spark Plasma Co-Sintering of Mechanically Milled Tool Steel and High Speed Steel Powders

    Directory of Open Access Journals (Sweden)

    Massimo Pellizzari

    2016-06-01

    Full Text Available Hot work tool steel (AISI H13 and high speed steel (AISI M3:2 powders were successfully co-sintered to produce hybrid tool steels that have properties and microstructures that can be modulated for specific applications. To promote co-sintering, which is made difficult by the various densification kinetics of the two steels, the particle sizes and structures were refined by mechanical milling (MM. Near full density samples (>99.5% showing very fine and homogeneous microstructure were obtained using spark plasma sintering (SPS. The density of the blends (20, 40, 60, 80 wt % H13 was in agreement with the linear rule of mixtures. Their hardness showed a positive deviation, which could be ascribed to the strengthening effect of the secondary particles altering the stress distribution during indentation. A toughening of the M3:2-rich blends could be explained in view of the crack deviation and crack arrest exerted by the H13 particles.

  11. Die owerheidsinmenging met betrekking tot kerklike tughandelinge.

    Directory of Open Access Journals (Sweden)

    L. Roeleveld

    1982-06-01

    Full Text Available Volgens art 29 NGB is die merktekens van die ware kerk die suiwere prediking van die Evangelie, die suiwere bediening van die Sakramente en die gebruik van die kerklike tug. Art. 32 NGB spreek uit dat die Kerkorde nie mag afwyk van wat Christus ingestel het nie. Menslike vindinge en wette om die gewetens te bind en te dwing, moet daarom verwerp word. Die ekskommunikasie of die ban moet toegepas word volgens die Woord van God.

  12. Pentateugtradisies in die boek Hosea

    African Journals Online (AJOL)

    om te bepaal of die verwysing na 'n gebeure te doen het met die verre verlede of met die .... Hosea 2:1-2 JHWH se trou aan sy beloftes. ... dat huile na Egipte sal terugkeer. Die presiese bedoeiing van die woorde 'huile sal terugkeer na Egipte' is omstre- de. Kommentatore soos Rudolph meen dat dit verstaan moet word as ...

  13. Die begrafnisdíens

    African Journals Online (AJOL)

    (De Vaux 1961:108). Was die begrafnis 'n familie of 'n kerklike aangeleentheid? Hierdie vraag word nie in die Bybel beantwoord nie. Abraham het sy vrou begrawe (Gen 23: 19-. 20). Isak en Ismael ..... ver gekom om die begrafnis 'n kerklike aangeleentheid te maak nie. Hierdie stap .... trou aan die sorg van God. * Die kerk ...

  14. Metodes in die Christelike etiek

    African Journals Online (AJOL)

    The basic question in Christian ethics is not primarily. 'What should I do?' The basic question is rather ' ... should therefore be accepted as being part of the method used in Christian ethics. 1. INLEIDEND ..... aan die kant van die onderdrukte' verkondig word, word die Christen opgeroep om horn te skaar aan die kant van die ...

  15. Aircraft Steels

    Science.gov (United States)

    2009-02-19

    component usage. PH 13-8Mo is a precipitation-hardenable martensitic stainless steel combining excellent corrosion resistance with strength. Custom 465 is...a martensitic , age-hardenable stainless steel capable of about 1,724 MPa (250 ksi) UTS when peak-aged (H900 condition). Especially, this steel can...NOTES 14. ABSTRACT Five high strength steels (4340, 300M, AerMet 100, Ferrium S53, and Hy-Tuf) and four stainless steels (High Nitrogen, 13

  16. Die teologiese skool in die P.U.K vir C.H.O.: met die betekenis van die teologiese skool vir die Christelike wetenskap

    Directory of Open Access Journals (Sweden)

    F. Postma

    1944-03-01

    Full Text Available Die Teologiese Skool van die Gereformeerde Kerk gedink op 29 November 1944 sy vyf-en-sewentigjarige bestaan.Die Raad en Senaat van die P.U.K. vir C.H.O. wil ook langs hierdie weg die Teologiese Skool van harte gelukwens en die versekering gee dat daar by die outoriteite van die P.U.K. ’n diepgevoelde dankbaarheid heers dat hierdie inrigting sovele jare deur onse God en Vader gedra en gespaar is.

  17. Brittle Fracture Behaviors of Large Die Holders Used in Hot Die Forging

    Directory of Open Access Journals (Sweden)

    Weifang Zhang

    2017-05-01

    Full Text Available Brittle fracture of large forging equipment usually leads to catastrophic consequences. To avoid this kind of accident, the brittle fracture behaviors of a large die holder were studied by simulating the practical application. The die holder is used on the large die forging press, and it is made of 55NiCrMoV7 hot-work tool steel. Detailed investigations including mechanical properties analysis, metallographic observation, fractography, transmission electron microscope (TEM analysis and selected area electron diffraction (SAED were conducted. The results reveal that the material generated a large quantity of large size polyhedral M23C6 (M: Fe and Cr mainly and elongated M3C (M: Fe mainly carbides along the martensitic lath boundaries when the die holder was recurrently tempered and water-cooled at 250 °C during the service. The large size carbides lead to the material embrittlement and impact toughness degradation, and further resulted in the brittle fracture of the die holder. Therefore, the operation specification must be emphasized to avoid the die holder being cooled by using water, which is aimed at accelerating the cooling.

  18. New trends in cold-chamber die casting machine design

    Directory of Open Access Journals (Sweden)

    R. Dańko

    2015-07-01

    Full Text Available Larger and larger proportions of aluminium castings, especially those produced by the die casting process, can be observed during recent years in the automotive industry, house-hold articles and others. In case of the automotive industry, apart from the traditional elements produced by the die pressure method such as engine blocks or crank shaft bedplates, aluminium is displacing steel from structural parts of cars (‘body in white’. The current state and development directions of the structural solutions of cold-chamber die castings are analysed in this paper. These solutions drive the prospective development of these machines and die casting technology. The focus is mainly on essential functional systems such as: hydraulic drives of closing and locking units, as well as pressing in die machines of known companies present on the European market.

  19. Die Frage nach Gerechtigkeit.

    Directory of Open Access Journals (Sweden)

    Martin Jäggle

    2014-07-01

    Full Text Available ENGLISH: In the first part six stages in the author’s path of life are described, which have influenced his engagement with justice. The second part gives an insight into his religious educational work, in which the issue of justice was especially significant on the example of ‘religion in the context of migration’ and of the ecumenic initiative ‘lebens.werte.schule’ (school worth living. The vision of the Kingdom of God and the necessity of participation become apparent. DEUTSCH: Im ersten Teil werden sechs Stationen am Lebensweg des Autors beschrieben, die seine Auseinandersetzung mit Gerechtigkeit geprägt haben. Der zweite Teil gibt Einblick in seine religionspädagogische Arbeit, in der die Frage nach Gerechtigkeit besonders bedeutsam war am Beispiel ‚Religion im Kontext Migration‘ und der ökumenischen Initiative ‚lebens.werte.schule‘. Die Vision vom Reich Gottes und die Notwendigkeit von Partizipation werden dabei deutlich.

  20. Die EG-Kabotageverordnung

    OpenAIRE

    Basedow, Jürgen

    1990-01-01

    Die EG-Kabotageverordnung : e. Schritt zur Verwirklichung d. Dienstleistungsfreiheit im Straßengüterverkehr / Jürgen Basedow ; Ansgar Held. - In: Europäische Zeitschrift für Wirtschaftsrecht. 1. 1990. S. 305-308

  1. Die Bibliothek des Bezirksmuseums Josefstadt

    Directory of Open Access Journals (Sweden)

    Maria Ettl

    2015-01-01

    Josefstadt in Wien werden die Herkunft der Bibliotheksbestände und die beengte Raumsituation beschrieben. Abschließend wird auf die Erfassung der Medien mittels der Bibliothekssoftware „Biblioweb“ eingegangen.

  2. Die verband tussen die sielkundige kontrak en organisasieverbondenheid

    Directory of Open Access Journals (Sweden)

    K. J. Stanz

    1999-06-01

    Full Text Available The relationship between the psychological contract and organisational commitment. The aim of this study is to design a measuring instrument with acceptable metric characteristics for the strength of the psychological contract within the South African context, and to determine empirically the relation between the strength of the psychological contract and organisational commitment. The Dhammanungune Model served as foundation for the design of the Strength of the Psychological Contract Questionnaire which consists of two scales namely, a needs expectation scale and a needs fulfilment expectation scale. The items of each scale have been formulated in the manner that ensures that the respondent reacts consecutively to two instructions namely, (a the level of the expectation and (b the importance of the expectation. This questionnaire was administered together with the Organisational Commitment Questionnaire to two population groups within the military environment. The Pearson Product Moment Correlation was calculated between the strength of the psychological contract and organisational commitment and the significance of the correlations was evaluated. Opsomming Die doel van die studie is om 'n meetinstrument met aanvaarbare metriese eienskappe vir die sterkte van die sielkundige kontrak vir Suid-Afrikaanse omstandighede te ontwerp en om empirics die verband tussen die sterkte van die sielkundige kontrak en organisasieverbondenheid te bepaal. Die sterkte van die sielkundige kontrak vraelys is op grond van die Dhammanungune-model ontwerp en het uit twee skale naamlik, die behoefteverwagting- en vervullingsverwagtingskale bestaan. Items vir eike skaal is sodanig geformuleer dat die respondent agteropeenvolgens op twee instruksies naamlik (a die vlak van die verwagting en (b die belangrikheid van die verwagting moet reageer. Die vraelys is saam met die organisasieverbondenheidsvraelys op twee populasies uit 'n militere omgewing toegepas. Die Pearson

  3. Die postpolitische Stadt

    Directory of Open Access Journals (Sweden)

    Erik Swyngedouw

    2013-12-01

    Full Text Available Die Polis ist tot, es lebe die kreative Stadt! Während die Stadt, zumindest in Teilen des städtischen Raums, blüht und gedeiht, scheint die Polis im idealisierten griechischen Sinn dem Untergang geweiht; in diesem Verständnis ist sie der Ort der öffentlichen politischen Auseinandersetzung und demokratischen Unterhandlung und somit eine Stätte (oft radikaler Abweichung und Unstimmigkeit, an der die politische Subjektivierung buchstäblich ihren Platz hat. Diese Figur einer entpolitisierten (oder postpolitischen und postdemokratischen Stadt im Spätkapitalismus bildet das Leitmotiv des vorliegenden Beitrags. Ich lehne mich dabei an Jacques Rancière, Slavoj Žižek, Chantal Mouffe, Mustafa Dikeç, Alain Badiou und andere Kritiker jenes zynischen Radikalismus an, der dafür gesorgt hat, dass eine kritische Theorie und eine radikale politische Praxis ohnmächtig und unfruchtbar vor jenen entpolitisierenden Gesten stehen, die in der polizeilichen Ordnung des zeitgenössischen neoliberalen Spätkapitalismus als Stadtentwicklungspolitik [urban policy] und städtische Politik [urban politics] gelten. Ziel meiner Intervention ist es, das Politische wieder in den Mittelpunkt der zeitgenössischen Debatten über das Urbane zu stellen. [...

  4. Effect of continuous and pulsed currents on microstructural evolution of stainless steel joined by TIG welding; Einfluss des Einsatzes von Dauerstrom und Impulsstrom auf die Mikrostrukturentwicklung bei durch das WIG-Schweissverfahren gefuegtem rostfreiem Stahl

    Energy Technology Data Exchange (ETDEWEB)

    Durgutlu, Ahmet; Findik, Tayfun; Guelenc, Behcet [Gazi Univ., Ankara (Turkey). Dept. of Metallurgy and Materials Engineering; Cevik, Bekir [Duezce Univ. (Turkey). Dept. of Welding Technology; Kaya, Yakup; Kahraman, Nizamettin [Karabuek Univ. (Turkey). Dept. of Manufacturing Engineering

    2015-07-01

    In this study, AISI 316L series austenitic stainless steel sheets were joined by tungsten inert gas welding method in continuous and pulsed currents. Regarding microstructural investigation and hardness values of weld metal, samples were welded to investigate the effect of current type on grain structures of weld metal. Results showed that samples welded by using pulsed current had considerable different properties compared to the samples welded by using continuous current. While the weld metals of joinings obtained by using continuous current displayed a coarse-grained and columnar structure, weld metals obtained by using pulsed current had a finer-grained structure. It was also found that hardness values of samples, which were welded with continuous and pulsed current, were quite different.

  5. Die histologie en ultrastruktuur van die hepatopankreas van die bloukurper Oreochromis mossambicus

    Directory of Open Access Journals (Sweden)

    M. M. Nel

    1990-07-01

    Full Text Available Die histologie en ultrastruktuur van die hepatopankreas van die bloukurper Oreochromis mossambicus word beskryf. ’n Dun bindweefselkapsel omring die lewer. Die hepatosietrangskikking vertoon as lobules, met die koorde van hepatosiete wat vanaf ’n sentrale vene uitradieer en met mekaar anastomaseer. Indiwiduele lewerlohules vertoon nie duidelike grense nie, maar enkele duidelike triades word wel in die lewer van O. mossambicus aangetref. Die hepatosiete bevat ’n enkele ronde kern met ’n duidelike nukleolus en die growwe endoplasmiese retikula kom in twee of meer rye om die kerne en teen die selgrense van die hepatosiete voor. Die ander sitoplasmiese organelle kom verspreid in die hepatosietsitoplasma voor. Die eksokriene pankreasselle is om die portale venes gesetel. Die kerne van hierdie selle is rond en is hasaal in die kubies- tot silindervormige selle gelee. ’n Goedontwikkelde growwe endoplasmiese retikulum — vesikulêr, tubulêr en sirkulêr in vorm — en sektretoriese granules wat apikaal in die sel gelee is, kom voor.

  6. Die teologiese arbeid van Antonius HJ Gunneweg

    African Journals Online (AJOL)

    En dis 'n klein treetjie van klagte na aanklag en na protes teen die gode, die heersers wat die mens vernietig deur hom oor sy ware lewe te bedrieg. Die ideologie eis dan ook dienooreenkomstig die bevryding en emansipasie van die mens van die gode en van God (1983: 118—119). Volgens die Jahwis is dit die slang wat, ...

  7. Research on the Effects of the Movable Die and its Counter Force on Sheet Hydroforming

    International Nuclear Information System (INIS)

    Zhou, Li X.; Zhang, Shi H.; Wang, Ben X.

    2007-01-01

    An improved Sheet Hydro-forming process was proposed, which was investigated in Institute of Metal Research, Chinese Academy of Sciences. ASAME system and FEM are used to analyze the forming process to explain some results that were found in the experiment. In the simulation, the effect of the movable die on the maximum principal stress is investigated in detail by using the FEM code LS-DYNA. For this case, the movable die changes the distribution of the maximum principal stress. For the sheet hydroforming without the movable die, the principal stress near the shoulder of the movable die arrives to the maximum value when t=0.0033s suddenly. But for the sheet hydroforming with the movable die, the maximum principal stress still lies in the die radius. The principal stress near the shoulder of the movable die is smaller. At the last stage contacting with the die, for the case without the movable die, the maximum principal stress near the shoulder of movable die is larger than that of the sheet hydroforming with the movable die. Moreover, the stress distribution near the shoulder of movable die for the case without the movable die is complicated. It is instable and very easy to occur wrinkling. The movable die delays the maximum thickness strain to the contacting die stage. So the formability of sheet metal can be remarkably improved by adopting the movable die. On a certain extent, the uniform distribution of thickness can be realized by increasing the counterforce of movable die. The minimum thickness reduction moves outside which is very helpful for the uniform thickness distribution. In this paper, two kinds of materials, soft steel and stainless steel, were investigated

  8. Die benutting van vraelyste met die oog op meer effektiewe ...

    African Journals Online (AJOL)

    UPuser

    effektiewe stresbeheer as een van die temas te hanteer. Op grond van die navorsing deur onder andere Lawson (1985) en Taylor (1999) sou ek graag die proses van differensiasie2 ook by genoemde lys voeg as tema vir bespreking tydens huweliksvoorbereiding. 2 Differensiasie kan beskryf word as die losmaakproses ...

  9. die aard van wetgewende diskresies by die suid-afrikaanse ...

    African Journals Online (AJOL)

    Administrator

    In enige moderne demokrasie is daar een of ander vorm van skeiding van magte tussen die wetgewende, uitvoerende en regsprekende gesag. Hierdie skeiding van magte, die sogenaamde trias politica, kan sover teruggevoer word as 1215, met die ondertekening van die Magna Carta deur Koning John van Engeland.

  10. die doeltreffendheid van die afrikaanse woordelys en spelreels

    African Journals Online (AJOL)

    sluiting by die reel vir die verdubbeling van medeklinkers na 'n kort, be- klemtoonde klinker, woorde soos ballet, ballon, terras, terrein, dissipel en dissipline slegs met een konsonant na die eerste vokaal gespel moes word, omdat daardie voorafgaande vokaal onbeklemtoon is. Ook hierdie uit- sondering op die reel word ...

  11. Die aanspraak op Goddelike steun in 'n konfliksituasie volgens die ...

    African Journals Online (AJOL)

    laws, and ethical or political principles. A synchronic investigation of relevant Old ... die toneel gebring met die vraag: 'aan wie se kant is God' (vgl bv The road to. Damascus 1979:6)? Volgens .... betrekking tot die Ou Testament: Hoe moet ons vasstel wie se kant God nou regtig kies, of wie veg aan die kant van God en wie ...

  12. Effect of heat treatment on the characteristics of tool steel deposited by the directed energy deposition process

    Science.gov (United States)

    Park, Jun Seok; Lee, Min-Gyu; Cho, Yong-Jae; Sung, Ji Hyun; Jeong, Myeong-Sik; Lee, Sang-Kon; Choi, Yong-Jin; Kim, Da Hye

    2016-01-01

    The directed energy deposition process has been mainly applied to re-work and the restoration of damaged steel. Differences in material properties between the base and the newly deposited materials are unavoidable, which may affect the mechanical properties and durability of the part. We investigated the effect of heat treatment on the characteristics of tool steel deposited by the DED process. We prepared general tool steel materials of H13 and D2 that were deposited onto heat-treated substrates of H13 and D2, respectively, using a direct metal tooling process. The hardness and microstructure of the deposited steel before and after heat treatment were investigated. The hardness of the deposited H13 steel was higher than that of wrought H13 steel substrate, while that of the deposited D2 was lower than that of wrought D2. The evolution of the microstructures by deposition and heat treatment varied depending on the materials. In particular, the microstructure of the deposited D2 steel after heat treatment consisted of fine carbides in tempered martensite and it is expected that the deposited D2 steel will have isotropic properties and high hardness after heat treatment.

  13. The FAQUIRE Approach: FAst, QUantitative, hIghly Resolved and sEnsitivity Enhanced 1H, 13C Data.

    Science.gov (United States)

    Farjon, Jonathan; Milande, Clément; Martineau, Estelle; Akoka, Serge; Giraudeau, Patrick

    2018-02-06

    The targeted analysis of metabolites in complex mixtures is a challenging issue. NMR is one of the major tools in this field, but there is a strong need for more sensitive, better-resolved, and faster quantitative methods. In this framework, we introduce the concept of FAst, QUantitative, hIghly Resolved and sEnsitivity enhanced (FAQUIRE) NMR to push forward the limits of metabolite NMR analysis. 2D 1 H, 13 C 2D quantitative maps are promising alternatives for enhancing the spectral resolution but are highly time-consuming because of (i) the intrinsic nature of 2D, (ii) the longer recycling times required for quantitative conditions, and (iii) the higher number of scans needed to reduce the level of detection/quantification to access low concentrated metabolites. To reach this aim, speeding up the recently developed QUantItative Perfected and pUre shifted HSQC (QUIPU HSQC) is an interesting attempt to develop the FAQUIRE concept. Thanks to the combination of spectral aliasing, nonuniform sampling, and variable repetition time, the acquisition time of 2D quantitative maps is reduced by a factor 6 to 9, while conserving a high spectral resolution thanks to a pure shift approach. The analytical potential of the new Quick QUIPU HSQC (Q QUIPU HSQC) is evaluated on a model metabolite sample, and its potential is shown on breast-cell extracts embedding metabolites at millimolar to submillimolar concentrations.

  14. Advanced cold rolled steels for automotive applications

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, H. [ThyssenKrupp Steel AG, Eberhardstrasse 12, 44145 Dortmund (Germany); Mattissen, D.; Schaumann, T.W. [ThyssenKrupp Steel AG, Duisburg (Germany)

    2006-09-15

    Advanced multiphase steels offer a great potential for bodies-in-white through their combination of formability and achievable component strength levels. They are first choice for strength and crash-relevant parts of challenging geometry. The intensive development of high-strength multiphase steels by ThyssenKrupp has led to hot dip galvanizing concepts with an outstanding forming potential. Hot rolled, hot dip galvanized complex phase steels are currently produced in addition to cold rolled DP and RA steels. New continuously annealed grades with tensile strength levels of up to 1000 MPa in combination with sufficient ductility for applications mainly in the field of structural automobile elements make use of the classic advantages of microalloying as well as the principles of DP and TRIP steels. Further improvement of properties will be reached by the new class of high manganese alloyed steels. (Abstract Copyright [2006], Wiley Periodicals, Inc.) [German] Fortschrittliche Multiphasen-Staehle eroeffnen wegen der inzwischen erreichbaren Kombination aus Umformbarkeit und Bauteilfestigkeit ein enormes Potenzial fuer Rohkarosserien. Sie stellen eine erste Wahl dar, wenn es um Festigkeit und um Crashsicherheit geht und besondere Anforderungen an die Bauteilgeometrien gestellt werden. Bei ThyssenKrupp hat die Entwicklung hochfester Multiphasen-Staehle in Verbindung mit dem Feuerverzinken zur Realisierung von Blechhalbzeugen gefuehrt, die hervorragend formbar sind. Es werden heute feuerverzinkte Komplexphasenstaehle neben den bewaehrten kaltgewalzten Dualphasen(DP) - und Retained Austenit(RA)-Staehlen produziert. Die neuen kontinuierlich gegluehten Stahlvarianten mit Festigkeiten bis zu 1000 MPa in Kombination mit der bei Strukturbauteilen im Automobilbau geforderten Duktilitaet nutzen sowohl die klassischen Vorteile des Mikrolegierens aus und dazu die Prinzipien, die man bei DP- und TRIP-Staehlen anwendet. Eine weitere Verbesserung des Eigenschaftsprofils wird mit dem

  15. Steel making

    CERN Document Server

    Chakrabarti, A K

    2014-01-01

    "Steel Making" is designed to give students a strong grounding in the theory and state-of-the-art practice of production of steels. This book is primarily focused to meet the needs of undergraduate metallurgical students and candidates for associate membership examinations of professional bodies (AMIIM, AMIE). Besides, for all engineering professionals working in steel plants who need to understand the basic principles of steel making, the text provides a sound introduction to the subject.Beginning with a brief introduction to the historical perspective and current status of steel making together with the reasons for obsolescence of Bessemer converter and open hearth processes, the book moves on to: elaborate the physiochemical principles involved in steel making; explain the operational principles and practices of the modern processes of primary steel making (LD converter, Q-BOP process, and electric furnace process); provide a summary of the developments in secondary refining of steels; discuss principles a...

  16. Die huwelik as identiteitsmerker in die Ou Testament

    African Journals Online (AJOL)

    p1243322

    Gen 2:18). Uit die woorde van Genesis 2:24 dat man en vrou een sal wees, lei die derde formulier af dat dit “getuig dat die huwelik 'n allesinsluitende gemeenskap is ..... die formule gebruik word: “Hier volg die vertelling oor X se nageslag.” (Gen ..... verwys daarna as “intertwining the principal value concepts of tradition”.

  17. Narratiwiteit en die Ou Testament

    African Journals Online (AJOL)

    INLEIDING. Die literêre benadering tot die Ou-Testamentiese narratiewe word algemeen as 'n alternatiewe paradigma in die Bybelwetenskappe aanvaar. Oor die filosofiese uit- gangspunte wat hierdie nuwe paradigma ten grondslag lê, bestaan daar egter nog weinig eenstemmigheid. Heelwat probleme van filosofiese en ...

  18. Eksistensialisme in die Franse letterkunde

    Directory of Open Access Journals (Sweden)

    A. A. Teurlinckx

    1966-03-01

    Full Text Available Nooit sou die Franse jeug — en die van Europa en verder — in dié mate deur die eksistensialisme be'invloed gewees het nie, indien hierdie filosofie in wysgerige traktate sou begrawe gelê het. Die eksistensialiste het die koning van die filosofiese verhaal, Voltaire, met sukses op sy Candide- en Zadig-pad gevolg en hulle teorieë in letterkundige werke, ver- hale, romans en ook toneelstukke kwytgeraak, wat baie gelees is en waaruit ook ander literatore kragte en inspirasie geput het. Omrede daarvan is daar inderdaad baie eksistensialisme in die Franse letterkunde, maar ’n eintlike eksistensialistiese letterkunde was daar nie, en ’n Eksistensialistiese Letterkun­ dige skool het nooit bestaan nie. Ook sit hierdie eksistensialiste nie langs dieselfde vuur nie. Die Christelike eksistensialis Gabriel Marcel het op 21 April van hierdie jaar uitgevaar teen die „Sartriane” na aanleiding van die opvoering van Les Paravents, Die W indskerms van Jean Genêt in ’n Paryse staatsondersteunde teater. „Mens mag seker wees”, skryf Marcel in Les Nouvelles Littéraires, „dat die hele sartriaanse parogie sal skreeu: groot meesterwerk”. Voortgaande op sy distansiëring kan die literêre eksistensialiste in drie groepe ingedeel word: 1. Die Sartriane; 2. Die Christelike Eksistensialiste; 3. Die Onafhanklikes.

  19. Assisted Dying in Canada.

    Science.gov (United States)

    Schuklenk, Udo

    This paper makes an affirmative ethical case in favour of the decriminalization of assisted dying in Canada. It then proceeds to defending the affirmative case against various slippery-slope arguments that are typically deployed by opponents of assisted dying. Finally, a recent case of questionable professional conduct by anti-euthanasia campaigners cum academics is flagged as a warning to all of us not to permit the quality of the professional debate to deteriorate unacceptably, despite the personal emotional investments involved on all sides of the debate.

  20. Genome and proteome analysis of 7-7-1, a flagellotropic phage infecting Agrobacterium sp H13-3

    Directory of Open Access Journals (Sweden)

    Kropinski Andrew M

    2012-05-01

    Full Text Available Abstract Background The flagellotropic phage 7-7-1 infects motile cells of Agrobacterium sp H13-3 by attaching to and traveling along the rotating flagellar filament to the secondary receptor at the base, where it injects its DNA into the host cell. Here we describe the complete genomic sequence of 69,391 base pairs of this unusual bacteriophage. Methods The sequence of the 7-7-1 genome was determined by pyro(454sequencing to a coverage of 378-fold. It was annotated using MyRAST and a variety of internet resources. The structural proteome was analyzed by SDS-PAGE coupled electrospray ionization-tandem mass spectrometry (MS/MS. Results Sequence annotation and a structural proteome analysis revealed 127 open reading frames, 84 of which are unique. In six cases 7-7-1 proteins showed sequence similarity to proteins from the virulent Burkholderia myovirus BcepB1A. Unique features of the 7-7-1 genome are the physical separation of the genes encoding the small (orf100 and large (orf112 subunits of the DNA packaging complex and the apparent lack of a holin-lysin cassette. Proteomic analysis revealed the presence of 24 structural proteins, five of which were identified as baseplate (orf7, putative tail fibre (orf102, portal (orf113, major capsid (orf115 and tail sheath (orf126 proteins. In the latter case, the N-terminus was removed during capsid maturation, probably by a putative prohead protease (orf114.

  1. Complete genome sequencing of Agrobacterium sp. H13-3, the former Rhizobium lupini H13-3, reveals a tripartite genome consisting of a circular and a linear chromosome and an accessory plasmid but lacking a tumor-inducing Ti-plasmid.

    Science.gov (United States)

    Wibberg, Daniel; Blom, Jochen; Jaenicke, Sebastian; Kollin, Florian; Rupp, Oliver; Scharf, Birgit; Schneiker-Bekel, Susanne; Sczcepanowski, Rafael; Goesmann, Alexander; Setubal, Joao Carlos; Schmitt, Rüdiger; Pühler, Alfred; Schlüter, Andreas

    2011-08-20

    Agrobacterium sp. H13-3, formerly known as Rhizobium lupini H13-3, is a soil bacterium that was isolated from the rhizosphere of Lupinus luteus. The isolate has been established as a model system for studying novel features of flagellum structure, motility and chemotaxis within the family Rhizobiaceae. The complete genome sequence of Agrobacterium sp. H13-3 has been established and the genome structure and phylogenetic assignment of the organism was analysed. For de novo sequencing of the Agrobacterium sp. H13-3 genome, a combined strategy comprising 454-pyrosequencing on the Genome Sequencer FLX platform and PCR-based amplicon sequencing for gap closure was applied. The finished genome consists of three replicons and comprises 5,573,770 bases. Based on phylogenetic analyses, the isolate could be assigned to the genus Agrobacterium biovar I and represents a genomic species G1 strain within this biovariety. The highly conserved circular chromosome (2.82 Mb) of Agrobacterium sp. H13-3 mainly encodes housekeeping functions characteristic for an aerobic, heterotrophic bacterium. Agrobacterium sp. H13-3 is a motile bacterium driven by the rotation of several complex flagella. Its behaviour towards external stimuli is regulated by a large chemotaxis regulon and a total of 17 chemoreceptors. Comparable to the genome of Agrobacterium tumefaciens C58, Agrobacterium sp. H13-3 possesses a linear chromosome (2.15 Mb) that is related to its reference replicon and features chromosomal and plasmid-like properties. The accessory plasmid pAspH13-3a (0.6 Mb) is only distantly related to the plasmid pAtC58 of A. tumefaciens C58 and shows a mosaic structure. A tumor-inducing Ti-plasmid is missing in the sequenced strain H13-3 indicating that it is a non-virulent isolate. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Die afrikaner en sy pers*

    Directory of Open Access Journals (Sweden)

    G. D. Scholtz

    1963-03-01

    Full Text Available Die versoek w at van u inrigting tot my gekom het om buitengewone professor in die Persw etenskap te word, was vir my deels vererend, m aar deels het dit my in 'n moeilike posisie gestel. Dit was vir my vererend, om dat dit gekom het van 'n universiteit m et wie se Christelik- Nasionale koers ek my ten voile kan vereenselwig. Dit was dan ook vir my vererend, om dat ek daardeur in staat gestel kan w ord om die volk w aartoe ek behoort, op 'n vir my nuwe terrein te dien. As sodanig is dit vir my im m ers m oontlik om ook ’n beskeie bydrae te lewer tot die geestelike vorm ing van die jeug van ons volk. Dit het my m oeilik geval om, w aar ek reeds die m iddeljarige leeftyd bereik het, nou vir die eerste maal as dosent op te tree, aangesien ek daarvan in die verlede nie die m inste kennis en ervaring opgedoen het nie. As joernalis rig ek my im m ers tot die breë publiek deur middel van die pen. As dosent m oet ek my deur middel van die mond tot die studente rig. Dit lê voor die hand dat die eise w at so aan my gestel word, totaal anders is as dié waar- aan ek oor 'n tydperk van m eer as 'n kw arteeu as joer­ nalis gewoond geraak het.

  3. Die vestiging van die Kerk in Natal, die Vrystaat en Transvaal na ...

    African Journals Online (AJOL)

    as eerste predikant van die Voortrekkers laat orden en bevestig. Daama het verskeie kerksake van tyd tot tyd aandag geniet. Met betrekking tot die bevestiging van huwelike stel Retief 'n meer ordelike reëling daar, naamlik dat die gebooie van voomemende egpa- re van nou af drie maal in die kerk afgekondig moes wrord ...

  4. Die skool en die onderwyser as faktore in die geestesgesondheid van die kind*

    Directory of Open Access Journals (Sweden)

    B. C. Schutte

    1961-03-01

    Full Text Available Ons hou geestesgesondheidsweke, stig beroepsentrums, samel geld in om mense wat geestelik siek is te genees, klae oor die tekort aan psigiaters, kliniese sielkundiges, bedryfsielkundiges, voorligters, skoolpsigoloë,ens. ’n Karige kwarteeu gelede het ons aan al hierdie dinge slegs akademiese aandag gewy. In hierdie kursus wordverskeie tipes kinders bespreek en geleer hoe om hulle probleme te benader.

  5. When Somebody Dies

    Science.gov (United States)

    ... bottle became useless. The container is gone, but what's inside — the water — remains. The part of a person that's left after the body dies is often called the "soul" or "spirit." Some people believe the soul is the part ...

  6. Die Kunst des Scheiterns

    DEFF Research Database (Denmark)

    Juul, Jesper

    2014-01-01

    Menschen haben von Kindesbeinen an das Verlangen, Erfolge zu erzielen und Kompetenz zu erreichen. Computerspieler entscheiden sich jedoch fortlaufend für eine Aktivität, die oft und wiederholt zum Verlieren führen muss und ein taubes Gefühl der Unfähigkeit erzeugt. Im Kino, im Theatersaal und bei...

  7. Modelle in die onderrig van fisika

    Directory of Open Access Journals (Sweden)

    J. J. A. Smit

    1998-07-01

    Full Text Available Die rol van modelle in die onderrig van fisika is sedert die vroeë tagtigerjare erken. In die onderrig word die absent op die kwantitaiewe aspekte van die vak geplaas, terwyl die kwatitatiewe aspekte min aandag kry.

  8. DIE SAGD - SY ONTSTAAN EN ONTWIKKELING

    African Journals Online (AJOL)

    31 Okt 1977 ... stelling van 'n higiene afdeling het in 'n belang- rike behoefte voorsien. Die pligte van die SAGO het dus op hierdie stadium die ondersoek van soldate, die sanita- sie van kampe, die verpleging van pasiente in militere hospitale en die opleiding van lede be- hels. 'n Hoogtepunt was die opening van die.

  9. Dimensional control of die castings

    Science.gov (United States)

    Karve, Aniruddha Ajit

    The demand for net shape die castings, which require little or no machining, is steadily increasing. Stringent customer requirements are forcing die casters to deliver high quality castings in increasingly short lead times. Dimensional conformance to customer specifications is an inherent part of die casting quality. The dimensional attributes of a die casting are essentially dependent upon many factors--the quality of the die and the degree of control over the process variables being the two major sources of dimensional error in die castings. This study focused on investigating the nature and the causes of dimensional error in die castings. The two major components of dimensional error i.e., dimensional variability and die allowance were studied. The major effort of this study was to qualitatively and quantitatively study the effects of casting geometry and process variables on die casting dimensional variability and die allowance. This was accomplished by detailed dimensional data collection at production die casting sites. Robust feature characterization schemes were developed to describe complex casting geometry in quantitative terms. Empirical modeling was utilized to quantify the effects of the casting variables on dimensional variability and die allowance for die casting features. A number of casting geometry and process variables were found to affect dimensional variability in die castings. The dimensional variability was evaluated by comparisons with current published dimensional tolerance standards. The casting geometry was found to play a significant role in influencing the die allowance of the features measured. The predictive models developed for dimensional variability and die allowance were evaluated to test their effectiveness. Finally, the relative impact of all the components of dimensional error in die castings was put into perspective, and general guidelines for effective dimensional control in the die casting plant were laid out. The results of

  10. Die transvaalse ontwerp-ordonnansie oor die onderwys

    Directory of Open Access Journals (Sweden)

    J. C. Coetzee

    1952-03-01

    Full Text Available In ’n Buitengewone Provinsiale Koerant van die Provinsie Transvaal is onder datum 25 Junie 1952 gepubliseer ’n „Ontwerp-Ordonnansie tot samevatting en wysiging van die Wette betreffende die Sentrale Beheer van die Onderwys, die Plaaslike Beheer van Skole, Godsdiensonderrig in Openbare Skole, Taal en die Onderwys, Onderwyspersoneel, Verpligte Onderwys, Toelating van Leerlinge tot Skole, Klasse of Inrigtings, Openbare Onderwys, Private Skole, Onderwys vir Kleurlinge en Asiate en Onderwys vir Naturelle, en om vir sake in verband daarmee voorsiening te maak” .

  11. DIE HEDENDAAGSE SIENING VAN DIE NORMERING VAN DUITS ...

    African Journals Online (AJOL)

    v a k t a a l k w a l i £ i k a s i e s ) neem d i e I n s t i t u t t a l l e take waar ter u i t b r e i d i n g van kennis van die Duitse taal in die buiteland. Sedert 1964 publiseer die. Institut die tydskrif Deutsch als Fremdsprache met die bylae Sprachpraxis, asook 'n handboek met die titel Deutsch - eln Lehrbuch Eur Auslander (Duits.

  12. Navigating "Assisted Dying".

    Science.gov (United States)

    Schipper, Harvey

    2016-02-01

    Carter is a bellwether decision, an adjudication on a narrow point of law whose implications are vast across society, and whose impact may not be realized for years. Coupled with Quebec's Act Respecting End-of-life Care it has sharply changed the legal landscape with respect to actively ending a person's life. "Medically assisted dying" will be permitted under circumstances, and through processes, which have yet to be operationally defined. This decision carries with it moral assumptions, which mean that it will be difficult to reach a unifying consensus. For some, the decision and Act reflect a modern acknowledgement of individual autonomy. For others, allowing such acts is morally unspeakable. Having opened the Pandora's Box, the question becomes one of navigating a tolerable societal path. I believe it is possible to achieve a workable solution based on the core principle that "medically assisted dying" should be a very rarely employed last option, subject to transparent ongoing review, specifically as to why it was deemed necessary. My analysis is based on 1. The societal conditions in which have fostered demand for "assisted dying", 2. Actions in other jurisdictions, 3. Carter and Quebec Bill 52, 4. Political considerations, 5. Current medical practice. Leading to a series of recommendations regarding. 1. Legislation and regulation, 2. The role of professional regulatory agencies, 3. Medical professions education and practice, 4. Public education, 5. Health care delivery and palliative care. Given the burden of public opinion, and the legal steps already taken, a process for assisted-dying is required. However, those legal and regulatory steps should only be considered a necessary and defensive first step in a two stage process. The larger goal, the second step, is to drive the improvement of care, and thus minimize assisted-dying.

  13. Investigations of the oxidation-induced service life of chromium steels for high temperature fuel cell application (SOFC); Untersuchungen zur oxidationsbedingten Lebensdauer von Chromstaehlen fuer die Anwendung in der Hochtemperaturbrennstoffzelle (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Ertl, S.T.

    2006-08-17

    The increasing energy consumption of future automobiles should be covered by a solid oxide fuel cell (SOFC) used as an additional energy supply (auxiliary power unit). The application of a SOFC with about 5 kW power in cars requires small size, low weight and an economic fabrication. To achieve this goal the interconnector and the metallic anode substrate (depending on an alternative concept of construction) should be manufactured out of thin Crofer22APU, a high chromium ferritic steel. The scale formation mechanisms on Crofer22APU sheets, wires and powder metallurgical produced foils of different thicknesses were investigated in several atmospheres of water vapour/hydrogen at 800 and 900 C, simulating the anode conditions. For scale characterization a number of conventional analysis techniques such as optical metallography, scanning electron microscopy and X-ray diffraction were used in combination with deflection testing in monofacial oxidation and two-stage oxidation studies using {sup 18}O and H{sub 2} {sup 18}O tracer. With these results a theoretical model for the determination of lifetime was developed for Crofer22APU components in simulated anode gas. It was found that the lifetime at a given temperature depends not only on the surface-to-volume ratio, but also on the geometry of the component (e.g. sheet or wire). The critical Cr content required for breakaway oxidation depends on microcrack formation in the surface oxide scale, which occurs on ridges of a sheet during thermal cycling. The development of a metallic interconnector and a metallic anode substrate requires measures to avoid interdiffusion between the alloy and the bordering nickel-YSZ (yttrium stabilized zirconia) cermet of the anode, or depending on the conception of the stack, the bordering nickel-YSZ cermet of the anode functional layer. Therefore the suitability of preoxidation layers after different preoxidation conditions was tested. It was found that the inhibition of the interdiffusion

  14. The Study on Weldability of Boron Steel and Hot-Stamped Steel by Using Laser Heat Source (Ⅲ) - Comparison on Laser Weldability of Boron Steel and Hot -Stamped Steel-

    Energy Technology Data Exchange (ETDEWEB)

    Choi, So Young; Kim, Jong Do [Korea Maritime and Ocean University, Busan (Korea, Republic of); Kim, Jong Su [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2015-01-15

    This study was conducted to compare the laser weldability of boron steel and hot-stamped steel. In general, boron steel is used in the hot-stamping process. Hot-stamping is a method for simultaneously forming and cooling boron steel in a press die after heating it to the austenitizing temperature. Hot-stamped steel has a strength of 1500 MPa or more. Thus, in this study, the laser weldability of boron steel and that of hot-stamped steel were investigated and compared. A continuous wave disk laser was used to produce butt and lap joints. In the butt welding, the critical cooling speed at which full penetration was obtained in the hot-stamped steel was lower than that of boron steel. In the lap welding, the joint widths were similar regardless of the welding speed when full penetration was obtained.

  15. The Study on Weldability of Boron Steel and Hot-Stamped Steel by Using Laser Heat Source (Ⅲ) - Comparison on Laser Weldability of Boron Steel and Hot -Stamped Steel-

    International Nuclear Information System (INIS)

    Choi, So Young; Kim, Jong Do; Kim, Jong Su

    2015-01-01

    This study was conducted to compare the laser weldability of boron steel and hot-stamped steel. In general, boron steel is used in the hot-stamping process. Hot-stamping is a method for simultaneously forming and cooling boron steel in a press die after heating it to the austenitizing temperature. Hot-stamped steel has a strength of 1500 MPa or more. Thus, in this study, the laser weldability of boron steel and that of hot-stamped steel were investigated and compared. A continuous wave disk laser was used to produce butt and lap joints. In the butt welding, the critical cooling speed at which full penetration was obtained in the hot-stamped steel was lower than that of boron steel. In the lap welding, the joint widths were similar regardless of the welding speed when full penetration was obtained

  16. Influencia del tiempo de nitruración en baño de sales en el comportamiento tribológico de un acero de herramientas AISI H13

    Directory of Open Access Journals (Sweden)

    Castro, G.

    2007-12-01

    Full Text Available Tribological high temperature characteristics of a H13 tool steel treated by salt bath have been studied. AISI H13 steel samples were nitrided by a sursulf bath, varying nitriding time from 1 to 24 h. Optical microscopy and micro-hardness deep profile through the nitrided layer were performed for each nitriding time. Standard pin-on-disk wear tests were conducted at high temperature. Sliding distance was varied from 150 m to 900 m. It has been observed that friction coefficient does not change with nitriding time and wear rate varies as a function of the sliding distance due to the presence of different wear mechanisms. For short sliding distances, the wear mechanisms that contribute to the total wear were plastic deformation and abrasion, whereas for greater sliding distances the mechanisms that control wear behaviour were oxidation and abrasion.

    Se han investigado las características tribológicas a alta temperatura de un acero de herramientas para trabajo en caliente nitrurado en baño de sales sursulf. Se ha variado el tiempo de nitruración desde 1 hasta 24 h, para analizar su influencia en la microestructura obtenida y en el comportamiento frente al desgaste. Se han realizado ensayos de desgaste a alta temperatura y se ha evaluado la ratio de desgaste y el coeficiente de fricción. Se ha observado que el coeficiente de fricción no varía con el tiempo de nitruración y que la ratio de desgaste varía con la distancia de deslizamiento debido a la presencia de distintos mecanismos de desgaste, pero es independiente del tiempo de nitruración. Así, para distancias de ensayo cortas, los mecanismos de desgaste que contribuyen al desgaste total son deformación plástica y abrasión, mientras que para mayores distancias de deslizamiento los mecanismos observados son oxidación y abrasión.

  17. Characteristics of Pilger Die Materials for Nuclear Zirconium Alloy Tubes

    International Nuclear Information System (INIS)

    Park, Ki Bum; Kim, In Kyu; Park, Min Young; Kahng, Jong Yeol; Kim, Sun Doo

    2011-01-01

    KEPCO Nuclear Fuel Company's (KEPCO NF) tube manufacturing facility, Techno Special Alloy (TSA) Plant, has started cold pilgering operation since 2008. It is obvious that the cold pilgering process is one of the key processes controlling the quality and the characteristics of the tubes manufactured, i.e. nuclear zirconium alloy tube in KEPCO NF. Cold pilgering is a rolling process for forming metal tubes in which diameter and wall thickness are reduced in a number of forming steps, using ring dies at outside of the tube and a curved mandrel at inside to reduce tube cross sections by up to 90 percent. The OD size of tube is reduced by a pair of dies, and ID size and wall thickness is controlled simultaneously by mandrel. During the cold pilgering process, both tools are the critical components for providing qualified tube. Development of pilger die and mandrel has been a significant importance in the zirconium tube manufacturing and a major goal of KEPCO NF. The objective of this study is to evaluate the life time of pilger die during pilgering. Therefore, a comparison of the heat treatment and mechanical properties of between AISI 52100 and AISI H13 materials was made in this study

  18. Die historiese betroubaarheid van die aartsvadervertellinge. 'n Beknopte bespreking van die huidige debat na aanleiding van die jongste publikasie

    Directory of Open Access Journals (Sweden)

    W. Vosloo

    1982-08-01

    Full Text Available Die afgelope twintig jaar was daar �n toenemende belangstelling in die aartsvadervertellinge in Genesis. Benewens die talle tydskrifartikels het skrywers soos die volgende ook boeke oor die onderwerp die lig laat sien: A. Parrot (1962, W. M. Clark (1964, R. Kilian (1966, R. E. Clements (1967, N. Lohfink (1967, H. Weidemann (1968, R. Martin-Achard (1969, T. L. Thompson (1974, J. van Seters (1975, J. P. Fokkelman (1975, C. Westermann (1976, R. Rendtorff (1977, J. Bright (1977, W. McKane (1979 en A. R. Millard en D. J. Wiseman (1980.

  19. 'n Kwalitatiewe ondersoek na die invloed van aspekte van die ...

    African Journals Online (AJOL)

    S Blignaut

    ISSN 0378-5254 Journal of Family Ecology and Consumer Sciences, Vol 26: No1, 1998. 15 ...... van byvoorbeeld die televisie en gedrukte media 'n invloed op die .... fashion promotion and advertising. New York. ... Consumer behaviour to-.

  20. Modeling the Mechanical Performance of Die Casting Dies

    Energy Technology Data Exchange (ETDEWEB)

    R. Allen Miller

    2004-02-27

    The following report covers work performed at Ohio State on modeling the mechanical performance of dies. The focus of the project was development and particularly verification of finite element techniques used to model and predict displacements and stresses in die casting dies. The work entails a major case study performed with and industrial partner on a production die and laboratory experiments performed at Ohio State.

  1. N HERSIENING VAN DIE AFRIKAANSE VERTALING VAN DIE ...

    African Journals Online (AJOL)

    Test

    vergewe. Dit sou in orde gewees het as daar gestaan het, ReMomë- j^onta^is hepta?ds. wat die grieks is vir sewentig maal sewe. Die uitdrukking. heMom&ontabis heptd sien hoogswaarskynlik op Gen. 4 : 24 (LXX) waar. Lameg meedeel dat hy sewe-en-sewentig-maal gewreek sal word. Daar sit die Afr. Vert, die uitdrukking ...

  2. Effect of Surface Modification on Corrosion Resistance of Uncoated and DLC Coated Stainless Steel Surface

    Science.gov (United States)

    Scendo, Mieczyslaw; Staszewska-Samson, Katarzyna

    2017-08-01

    Corrosion resistance of 4H13 stainless steel (EN-X46Cr13) surface uncoated and coated with an amorphous hydrogenated carbon (a-C:H) film [diamond-like carbon (DLC)] in acidic chloride solution was investigated. The DLC films were deposited on steel surface by a plasma deposition, direct current discharge (PDCD) method. The Fourier transform infrared (FTIR) was used to determine the chemical groups existing on DLC films. The surface of the specimens was observed by a scanning electron microscope (SEM). The tribological properties of the both materials were examined using a ball-on disk tribometer. The microhardness (HV) of diamond-like carbon film increased over five times in relation to the 4H13 stainless steel without of DLC coating. Oxidation kinetic parameters were determined by gravimetric and electrochemical methods. The high value of polarization resistance indicates that the DLC film on substrate was characterized by low electrical conductivity. The corrosion rate of 4H13 stainless steel with of DLC film decreased about eight times in relation to uncoated surface of 4H13 stainless steel.

  3. VizieR Online Data Catalog: L1157-B1 DCN (2-1) and H13CN (2-1) datacubes (Busquet+,

    Science.gov (United States)

    Busquet, G.; Fontani, F.; Viti, S.; Codella, C.; Lefloch, B.; Benedettini, M.; Ceccarellli, C.

    2017-06-01

    IRAM NOEMA observations of DCN(2-1) and H13CN(2-1) towa brightest bow-shock B1 of the L1157 molecular outflow. All data cubes are provided in fits format smoothed to a velocity resolution of 0.5km/s. (2 data files).

  4. Film Presentation: Die Urknallmaschine

    CERN Multimedia

    Carolyn Lee

    2010-01-01

    Die Urknallmaschine, an Austrian film by Gerd Baldauf, narrated by Norbert Frischauf (Alpha Österreich - ORF, 2009).  In CERN’s gigantic complex particles are accelerated to almost the speed of light, brought to collision and made to divide into even smaller particles. Public opinion of CERN’s research is also divided. Sceptics fear that black holes may be created. Might the goal to study the origin of the world lead to its destruction? The Austrian researcher Norbert Frischauf worked at CERN for many years. With his guidance it is possible to explore the world’s largest research centre, get a glimpse of the fascinating work the scientists do there and take a crash course in particle physics. Die Urknallmaschine will be presented on Friday, 25 June from 13:00 to 14:00 in the Main Auditorium. Language: German

  5. Dying for security

    Directory of Open Access Journals (Sweden)

    Buchan, Bruce

    2011-01-01

    Full Text Available If political statements and media coverage are any guide, it seems Australians today are dying for security. At no other moment in our history has the spectre of war and terrorism so haunted popular, political and scholarly perceptions of Australia’s colonial past and of its geopolitical future. And yet, debates over colonial war or genocide and contemporary terrorism have been conducted in more or less complete isolation. In this article I argue that our contemporary obsession with ‘security’ is premised on the perennial threat of ‘insecurity’. This is the problem of in/security, and it has played a central role in the development of Western political thought. More importantly, its formulation in Western political thought provided a powerful justification for the violence of the early decades of Australia’s colonisation during which Indigenous Australians could also be said to have been dying for security.

  6. Dying for Security

    Directory of Open Access Journals (Sweden)

    Bruce Buchan

    2011-03-01

    Full Text Available If political statements and media coverage are any guide, it seems Australians today are dying for security. At no other moment in our history has the spectre of war and terrorism so haunted popular, political and scholarly perceptions of Australia’s colonial past and of its geopolitical future. And yet, debates over colonial war or genocide and contemporary terrorism have been conducted in more or less complete isolation. In this article I argue that our contemporary obsession with ‘security’ is premised on the perennial threat of ‘insecurity’. This is the problem of in/security, and it has played a central role in the development of Western political thought. More importantly, its formulation in Western political thought provided a powerful justification for the violence of the early decades of Australia’s colonisation during which Indigenous Australians could also be said to have been dying for security.

  7. N HERSIENING VAN DIE AFRIKAANSE VERTALING VAN DIE ...

    African Journals Online (AJOL)

    Test

    aangetoon het, 'n huis in Kapernaum gehad en hierdie geskiedenis speel in Kapernaum of daar digby af. Jesus en sy dissipele het namelik, volgens 6:35 geland by Gennesaret, net suid van Kapernaum Die gevolgtrekking word ondersteun deur Joh. 6:17 waarvolgens die dissi pele na die spysiging op Kapernaum gevaar ...

  8. 'n Verkenning van die soorte vennootskappe in die Amerikaanse reg ...

    African Journals Online (AJOL)

    In die Amerikaanse literatuur word talle verwysings gevind na die vennootskap in mynbou ("mining partnership"), familievennootskap ("family partnership", vennootskap in vaste eiendom ("partnership in real estate") en vennootskap vir boerdery ("farming partnership"). Hierdie onderskeiding is primer gebaseer op die tipe ...

  9. Geslagsverskille in die ouditiewe ontlokte potensiaal van die brein

    Directory of Open Access Journals (Sweden)

    Anita D Stuart

    2006-10-01

    Full Text Available Gender differences in the auditory evoked potential of the brain. Based on literature indications of an association between temperament characteristics and the evoked potential of the brain, and indications of gender differences in certain temperament traits, the purpose of this study was to ascertain whether evoked responses also differentiated between the genders. A sample of 81 male and 210 female students was randomly selected. Two auditory evoked potential procedures were applied. The results indicated statistically significant differences in evoked potential responses between the genders. The results are interpreted against the background of sensory and neurological sources of the evoked potential responses and linked to the neurophysiological foundations of temperament. Opsomming: Gegrond op aanduidings in die literatuur van ’n assosiasie tussen temperamentskenmerke en die ontlokte potensiaal van die brein, sowel as aanduidings van geslagsverskille in sekere temperamentstrekke, was die doel van die huidige studie om te bepaal of ontloktepotensiaal-response ook tussen die geslagte onderskei. ’n Steekproef van 81 manlike en 210 vroulike studente is ewekansig geselekteer. Twee ouditiewe ontloktepotensiaal- prosedures is toegepas. Die resultate het op statisties beduidende verskille tussen die geslagte gedui. Die bevindinge word teen die agtergrond van die sensoriese en neurologiese oorsprong van ontloktepotensiaal–response geïnterpreteer en verbind aan die neurofisiologiese verankering van temperament.

  10. Die 'postmoderne' stempel in die Nuwe-Testamentiese hermeneutiek

    African Journals Online (AJOL)

    georiënteerde teorie en kritiek wat volgens Moore opbou tot 'n herhaling binne. Bybelnavorsing. Dit het reeds by Immanuel Kant begin. Sedert Kant is dit proble- maties cm die objek van kennis te beskou as iets wat kennis objektief in sigself bevat. Objektiwisme is prys gegee. Dialektiek het in die plek daarvan gekom. Die.

  11. duele verse sowel as die somtotaal die leser

    African Journals Online (AJOL)

    27 Jan 2006 ... selfs 'n landkaart afgedruk) terwyl dit ter- selfdertyd ver bo die lokale uitstyg. Die digter is sterk bewus van sy omgewing, geskiedenis en tradisies, maar veral van die algemene menslike kondisie wat binne hierdie referensiekader vergestalt word. Hy gebruik 'n bekende historiese slagveld as bundeltitel (en ...

  12. Die Leben Einsteins eine Reise durch die Geschichte der Physik

    CERN Document Server

    Fiami

    2005-01-01

    Jeder kennt die Namen Einstein, Newton oder Galilei. aber was weiss man über sie? Hier ein Porträt Einsteins anhand von sechs Meilensteinen aus der Geschichte der Physik. Einstein tritt auf als Protagonist in verschiedenen Epochen und bei verschiedenen Entdeckungen, die die Welt verändert haben.

  13. DIE KONINGSBEDE AS ELEMENT IN DIE KRONINGSRITUEEL. By ...

    African Journals Online (AJOL)

    Test

    Die offerfees te Gibeon was 'n plegtigheid, waaraan geheel Israel deelgeneem het. Die duisend. "brandoffers" wat sowel Kon. as Kron. vermeld, sal wel opgevat moet word as „brandoffers en dankoffers", sodat daar vir die aanwesiges. *n groot feesmaaltyd aangerig is, vgl. I Kon. 3:15. n Sodanige maal- tyd verbind vors en ...

  14. Ruimtelike beplanning: die rol van die stads - en streeksbeplanner ...

    African Journals Online (AJOL)

    Ruimtelike beplanning: die rol van die stads - en streeksbeplanner in die saw. R Erasmus. Abstract. Since 1978 regional and town planners are employed in the SADF on a permanent basis as well as in the capacity of national service men. These men are all academically qualified and as such satisfy a need that developed ...

  15. n opinie oor die behaviouristiese siening versus die fenomenologie ...

    African Journals Online (AJOL)

    verband die eksperimente van Pavlov, Thorndike,. Skinner, Tolmann en Hull.) Fenomenologie. Die fenomenologie is 'n essensie-openbarende denkrigting. Dit impliseer'n denkende soektog na dit wat 'n besondere verskynsel of werklikheid maak juis dit wat dit is en nie iets anders nie. In die fenomenologiese antropologie ...

  16. An assessment of the performance of the immunity system in iron and steel workers exposed to hazardous industrial factors. Pt. 2. Regulation of immuno-deficiencies in iron and steel workers suffering from chronic bronchitis. Die Beurteilung der Leistung des Immunsystems bei Huettenarbeitern unter Einwirkung schaedlicher industrieller Faktoren. T. 2. Regulierung von Immundefiziten bei Erzhuettenarbeitern mit chronischer Bronchitis

    Energy Technology Data Exchange (ETDEWEB)

    Scheller, S.; Czuba, Z.; Krol, W.; Nikodemowicz, E.; Aleksandrowicz, J.; Zydowicz, G. (Inst. for Microbiology, Medical Academy, Zabrze-Rokitnica (Poland)); Shani, J. (Univ. of South California, School of Pharmacy, Los Angeles, CA (USA)); Malinowska, B. (Sanatorium for Lung Diseases and Tuberculosis, Bystra Slaska (Poland))

    1991-05-01

    147 iron and steel workers suffering from chronic bronchitis underwent a 24 days climatic treatment. A local antibacterial treatment was empolyed as well as local and systemic regulation of the immunosystem. Significant immuno-deficiencies were found in the patients concerned. EEP in an isotonic saline solution was applied locally by means of inhalations as a remedy with antibacterial and immunotropic effects. The systematic immunotherapy was carried out by administering Propolin tablets, Dolomit, Methindol (Indomethazin), Biostymina, and Decaris (Levamisole). After the treatment we stated a favorable change of several parameters. (orig.).

  17. Die Vier Typen von Projektmanagern

    DEFF Research Database (Denmark)

    Lund Pedersen, Carsten; Ritter, Thomas

    2018-01-01

    Bevor Sie einem Mitarbeiter die Leitung eines Projekts anvertrauen, sollten Sie sich über dessen Managementstil klar werden. Passt dieser nicht zur Art des Vorhabens, wird er scheitern. So treffen Sie die richtige Wahl....

  18. Die historiese Jesus as wondenverker

    African Journals Online (AJOL)

    Biblical Association, te wete 'The social sciences and second Testament exegesis'. John Pilch is die leier van die Society of Biblical Literature se 'Social sciences and ..... Hollenbach, P 1982. ... Stauffer, E 1982. Jesus ... London: Collins.

  19. Precision die design by the die expansion method

    CERN Document Server

    Ibhadode, A O Akii

    2009-01-01

    This book presents a new method for the design of the precision dies used in cold-forging, extrusion and drawing processes. The method is based upon die expansion, and attempts to provide a clear-cut theoretical basis for the selection of critical die dimensions for this group of precision dies when the tolerance on product diameter (or thickness) is specified. It also presents a procedure for selecting the minimum-production-cost die from among a set of design alternatives. The mathematical content of the book is relatively simple and will present no difficulty to those who have taken basic c

  20. Die Dokter-Pasient Rolverwantskap

    African Journals Online (AJOL)

    17 Aug 1974 ... en as sodanig 'n ral sped in die persoon se siektegedrag en uiteindelike patroon van hulpsoeke. SIEKEROL EN SOSIALISERING IN DIE. PASIENTROL ..... more cumulative, resulting in a more gradual social and professional maturation.' Vit die voorafgaande word dit duidelik dat Dewy se pragmatiese ...

  1. prosesseringsmetodes op die voedingswaarde van

    African Journals Online (AJOL)

    gebring is, kon geen betekenisvolle verskille tussen die drie monsters gevind word nie. Volgens Opstvedt (1976) kan ME waardes ook dien as 'n kriteria van proteien- kwaliteit, hoofsaaklik a.g.v. die verhoogde stikstofuit- skeiding in die urine wat sal plaasvind a.g.v. beskadiging van aminosure. De Groote (1968) het gevind ...

  2. DIE SAW SE ROL IN SWA

    African Journals Online (AJOL)

    wei die verdediging van die landsgrense teen 'n vyand wat die orde, gesag, vrede, stabiliteit en welvaart in Suidwes-Afrika en die Republiek van. Suid-Afrika wil vernietig. Hierdie oorlog moet nie ge'lsoleerd gesien word nie, maar in perspektief geplaas word teen die agtergrond van 'n nag groter konflik, naamlik die van die ...

  3. Die Subjektiewe en Objektiewe doelwitte van Arbeid

    Directory of Open Access Journals (Sweden)

    T. H. Veldsman

    1982-11-01

    Die artikel gee aandag aan die subjektiewe en objektiewe doelwitte van arbeid. Hul plek en funksie binne 'n voorgestelde geïntegreerde motiveringsmodel word eerstens aangedui. Vervolgens word die verwantskap tussen die twee doelwitte uitgelig, gevolg deur 'n bespreking van die aard van die objektiewe doel. Laastens word die invloed van moderne arbeid op hierdie doelwitte uitgestippel.

  4. DIE EKSISTENSIEFILOSOFIE VAN KARL JASPERS. ENKELE ...

    African Journals Online (AJOL)

    Test

    Kierkegaard en Nietzsche, Max Weber en Dilthey, om maar enkeles te noem, en 5.) Jaspers se persoonlike beskouing oor die roe ping en die taak van die Filosofie, sy aanvoeling van die filosofiese problematiek en sy grondhouding teenoor die eksistensiële verbonden- hede. Die woord van Fichte, naamlik dat die Filosofie ...

  5. Dying with dignity.

    Science.gov (United States)

    Madan, T N

    1992-08-01

    Death is a theme of central importance in all cultures, but the manner in which it is interpreted varies from society to society. Even so, traditional cultures, including Christian, Hindu and Jain religious traditions, exhibited a positive attitude to death and did not look upon it in a dualistic framework of good vs bad, or desirable vs undesirable. Nor was pessimism the dominant mood in their thinking about death itself. A fundamental paradigm shift occurred in the West in the eighteenth century when death was desacralized and transformed into a secular event amenable to human manipulation. From those early beginnings, dying and death have been thoroughly medicalized and brought under the purview of high technology in the twentieth century. Once death is seen as a problem for professional management, the hospital displaces the home, and specialists with different kinds and degrees of expertise take over from the family. Everyday speech and the religious idiom yield place to medical jargon. The subject (an ageing, sick or dying person) becomes the object of this make-believe yet real world. As the object of others' professional control, he or she loses the freedom of self-assessment, expression and choice. Or, he or she may be expected to choose when no longer able to do so. Thus, not only freedom but dignity also is lost, and lawyers join doctors in crisis manipulation and perpetuation. Although the modern medical culture has originated in the West, it has gradually spread to all parts of the world, subjugating other kinds of medical knowledge and other attitudes to dying and death.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Sal die ‘ewolusie’ vanaf biologie na lewenswetenskappe ‘uitsterwing’ van die vakgebied voorkom?

    Directory of Open Access Journals (Sweden)

    Johanna G. Ferreira

    2012-03-01

    Full Text Available In hierdie artikel word die wysiging van die skoolvak van ‘biologie’ na ‘lewenswetenskappe’ bespreek, asook die gepaardgaande en verwagte implikasies van die verandering. Die vraag word gestel of die beoogde wysiging wel noemenswaardig is en of dit enigsins ‘n verskil aan die dalende belangstelling in die lewenswetenskappe op tersiêre vlak sal maak. Die wysigings in die nuwe kurrikula verhoog die relevansie van die vakinhoud vir leerders en vir die gemeenskap, maar sekere kwessies kry nie aandag nie. Voorstelle word gemaak om die kurrikulum te wysig en onderrigmetodes aan te pas om die nodige vaardighede by leerders te vestig.

  7. enkele fasette van die problematiek van die akademikus by die skryf

    African Journals Online (AJOL)

    Om verskeie redes het dit van die allergrootste belong geword dot 'n his- tories korrekte, wetenskaplike weerga- we van bogenoemde gebeure opge- teken moet word. Die sluier, in sommige gevalle am logiese redes toegepas, moes eenvoudig gelig word am gebeure wat die gewone man op stroot in Suid-Afrika dikwels ...

  8. Die Defects and Die Corrections in Metal Extrusion

    Directory of Open Access Journals (Sweden)

    Sayyad Zahid Qamar

    2018-05-01

    Full Text Available Extrusion is a very popular and multi-faceted manufacturing process. A large number of products for the automotive, aerospace, and construction sectors are produced through aluminum extrusion. Many defects in the extruded products occur because of the conditions of the dies and tooling. The problems in dies can be due to material issues, design and manufacturing, or severe usage. They can be avoided by maintaining the billet quality, by controlling the extrusion process parameters, and through routine maintenance. Die problems that occur on a day-to-day basis are mostly repairable and are rectified through various types of die correction operations. These defects and repair operations have not been reported in detail in the published literature. The current paper presents an in-depth description of repairable die defects and related die correction operations in metal extrusion. All major die defects are defined and classified, and their causes, preventive measures, and die correction operations are described. A brief frequency-based statistical study of die defects is also carried out to identify the most frequent die corrections. This work can be of direct benefit to plant engineers and operators and to researchers and academics in the field of metal extrusion.

  9. Die hermeneutiek van gereformeerde kerkreg

    Directory of Open Access Journals (Sweden)

    Andries le Roux du Plooy

    2012-10-01

    Full Text Available Die artikel het op die belangrikheid en noodsaaklikheid van ‘n hermeneutiek vir die gereformeerde kerkreg gefokus. Die kerkregtelike dokument wat besonderlik ter sake was, is die kerkorde van die Gereformeerde kerke in Suid-Afrika, met sy besondere band met die Dordtse kerkorde van 1618 en 1619. Agtereenvolgens is aandag gegee aan die volgende aspekte soos (1 die eiesoortige aard van ‘n kerkorde as ‘n teologiese dokument en teks, in onderskeiding van regsdokumente; (2 die aard van die hermeneutiek van kerkreg; (3 enkele teorieë oor die interpretasie of uitleg van tekste, veral regstekste en (4 normatiewe vooronderstellings en reëls vir die interpretasie en verstaan van die teks en artikels van die kerkorde asook besluite van kerklike vergaderinge. Die gevolgtrekking was dat weinig indringende navorsing gedoen is oor die saak van hermeneutiek vir kerkreg, hoewel dit noodsaaklik is. Duidelike hermeneutiese reëls is gesuggereer en verduidelik, wat sou kon meehelp dat kerke en kerklike vergaderinge die artikels van die kerkorde asook besluite en reglemente wat daarop berus het, kan interpreteer en toepas. The hermeneutics of reformed church polity. The article focused on the importance and urgency of a design for reformed hermeneutics on church polity. The Church Order referred to in the article is the Church Order of the Reformed Churches in South Africa, which are closely related to the Church Order of Dordt of 1618 and 1619. The following aspects received attention namely (1  the unique character of a Church Order, in comparison to and distinguished from legal documents and statutes; (2 the character and nature of hermeneutics of church polity; (3 theories of interpretation in the common law tradition and their relevance to church polity and (4 normative presuppositions and marks for the interpretation and understanding of the text and articles of the Church Order, as well as the resolutions of church assemblies. It was found that

  10. Die verband tussen lokus van beheer en die werks prestasie van swart bemarkers in die lewensversekeringsbedryf

    Directory of Open Access Journals (Sweden)

    E. L. Coetzer

    1997-06-01

    Full Text Available The relationship between locus of control and the work performance of black marketers in the life assurance industry. The aim of the study was to establish the relationship between locus of control and the work performance of black marketers in the life assurance industry. These constructs were selected by virtue of the lack of empirical research regarding the assumed relationship between them. The Locus of Control Scale of Schepers (1995 was used for measuring locus of control. Work performance was measured by the commission earned per month by the marketer, the number of policies generated by the marketer, as well as the percentage of lapsed policies. The relevant measurements were obtained in respect of a sample of 149 black marketing personnel. The results indicated a modest but statistically significant relationship between external locus of control and the work performance of black marketers. Opsomming Die doel van die studie was om die verband tussen lokus van beheer en die werksprestasie van swart bemarkers in die lewensversekeringsbedryf te bepaal. Hierdie konstrukte is gekies op grond van die gebrek aan empiriese navorsing rakende die veronderstelde verband tussen genoemde konstrukte. Die Lokus van Beheer-vraelys van Schepers (1995 is in die meting van lokus van beheer gebruik. Werksprestasie is aan die hand van kommissie per maand verdien, aantal polisse gegenereer deur 'n bemarker en die persentasie vervalde polisse, gemeet. Die tersaaklike metinge is verkry ten opsigte van 'n steekproef van 149 swart bemarkers. Die resultate toon 'n klein, dog statisties beduidende verband tussen eksterne lokus van beheer en die werksprestasie van swart bemarkers in die lewensversekeringsbedryf.

  11. Is die ortodoksie se verstaan van die sondeval belemmerend vir die gesprek tussen teologie en natuurwetenskap?

    Directory of Open Access Journals (Sweden)

    Johan Buitendag

    2012-11-01

    Full Text Available In hierdie artikel is betoog dat die Gereformeerde Ortodoksie se begrip van die sondeval ’n  belemmering  was  vir  die  gesprek  tussen  teologie  en  natuurwetenskap.  Die  rede hiervoor was dat dit ten eerste ’n bepaalde verstaan van liniêre tyd nahou en ten tweede dat dit ’n bonatuurlike ingryp veronderstel het. Albei hierdie aspekte het die debat onnodig problematiseer. Die argument is ontwikkel deur eerstens die probleem te definieer, gevolg deur ’n uiteensetting van die standpunte van Augustinus en Calvyn onderskeidelik oor die sondeval. As ’n heuristiese sleutel is die konsepte van infralapsarisme en supralapsarisme aangewend om die tema te ontleed. Die artikel is afgesluit met die oortuiging dat die imago Dei ’n beliggaamde menslike persoon is wat biologies in die geskiedenis in terme van selfbewussyn en morele verantwoordelikheid ontluik het. Is the Orthodoxy’s notion of the Fall inhibitory for the dialogue between theology and science? In this article it was argued that the Reformed Orthodoxy’s interpretation of the Fall had become an impediment in the dialogue between theology and science. The reason was that it assumed firstly a specific understanding of linear time and secondly a metaphysical intervention. Both events were unnecessarily problematising the debate. The argument was deployed by stating the problem, followed by an exposition of the views of Augustine and Calvin on the Fall. As a heuristic key, the concepts of infralapsarism and supralapsarism were applied respectively to analyse the topic. The article concluded with the conviction that the imago Dei is an embodied human person that had biologically emerged in history as a center of self-awareness, and moral responsibility.

  12. Sedimentêre omgewings van die Inhaca-eilandstelsel met spesiale verwysing na die petrografiese en geochemiese eienskappe van die sedimente spesiale verwysing na die petrografiese en geochemiese eienskappe van die sedimente

    Directory of Open Access Journals (Sweden)

    Marieke Peché

    2011-09-01

    Full Text Available Die Inhaca-eilandstelsel is geleë langs die suidooskus van Mosambiek. Die oostekant van die stelsel grens aan die Indiese Oseaan en die westekant aan die Baai van Maputo. Hierdie eilandstelsel bestaan uit Inhaca- en Portugese eiland, asook ’n groep sandbanke wat van die noordlike punt van Inhaca na Portugese eiland strek. Die doel van hierdie studie is om die verskillende moderne en oer-sedimentêre omgewings op die eilandstelsel te identifiseer en te beskryf, die invloed van getye en golfaksie op die moderne sedimentêre omgewing vas te stel en die geochemiese en petrografiese samestelling van die geologiese eenhede te bepaal.

  13. Die Face Engineering based Springback Compensation Strategy and Implementation

    International Nuclear Information System (INIS)

    Tang, Arthur; Lee Wing; He, Jeanne; Xu Jinbo; Liu Kesu; Chen Chinchun

    2005-01-01

    Springback or shape change has been one of the major challenges in sheet metal fabrication, particularly with increase application of high strength steel (HSS) and aluminum alloys in automotive stamping. Springback, an elastic material recovery after the unloading of stamping tools, causes variations and inconsistencies of final part dimensions. Minor or mild springback usually can be corrected in the re-strike process. Excessive springback must be corrected so the part will be produced within the given design tolerance and dimension. The commonly used Spring Forward approaches and shape compensations such as over-crown and over-bending are proven effective to alleviate excessive springback. To enhance these approaches, a new strategy of Die Face Engineering (DFE) based processing is proposed to quickly and easily to achieve the maximum allowable compensation using the under cut (or die lock) as the primary criteria. The implementation of the die face compensation through iterative FEA calculation, automatic surface mapping, projection and manual morphing are crucial to meet production environment requirements in terms of generating NC quality CAD surfaces of the compensated or morphed die face. In this paper, the strategy of the die face compensation with the consideration of the under cut criteria is presented. The implementation of various processes to enable user to perform the die face compensation task in a production environment is also discussed. Finally, two examples are shown to demonstrate the implementation of the proposed springback compensation scheme based on the combined CAE/CAD methodology

  14. Die vangnet van die woord: forensies-linguistiese getuienis in 'n ...

    African Journals Online (AJOL)

    Een van die redes daarvoor is waarskynlik die gepaardgaande sleurwerk verbonde aan die verwerking van die betrokke taaldata — iets wat egter deur die onlangse meteoriese vooruitgang in tegnologiese tegnieke op die agtergrond geskuif is en nuwe moontlikhede na vore laat kom het. In die lig van die kompleksiteit van ...

  15. het om die Woord van God aan die gemeente te bedien. A. D. P ont ...

    African Journals Online (AJOL)

    Test

    Sizoo vertel met die vlotheid van die ervare skrywer en die ver antwoordelikheid van die wetenskaplike ... Maar in stiptelike trou aan die feitelikheid, verlaat die skrywer hom uitsluitlik op die outentieke bronne om ... de leser; in sy rykdom van gegewens en wetenskaplike betroubaarheid kan dit met vrug gelees word deur die ...

  16. Die invloed van herbivorie en vuur op die oorlewing van sekere meerjarige kruide langs die Sabierivier, Kruger Nasionale Park

    Directory of Open Access Journals (Sweden)

    H. Myburgh

    2012-03-01

    Full Text Available Die groot vloede wat in die jaar 2000 in die Kruger Nasionale Park plaasgevind het, het dierivieroewerplantegroei versteur. Dit het die geleentheid gebied om heinings op te rig langsdie Sabierivier om herbivore uit sekere gebiede uit te sluit en sodoende die herstel van die rivieroewerekosisteme te monitor.

  17. Die heelal en sy onstaan (II

    Directory of Open Access Journals (Sweden)

    D. J. Van Rooy

    1952-03-01

    Full Text Available Ons kennis en wetenskap van die hemelliggame word volkome bepaal deur die lig wat ons van hulle ontvang, d.w.s. as ons die feite wat die Bybel daaromtrent meedeel, buite rekening laat.

  18. Nanostructure and Properties of Corrosion Resistance in C+Ti Multi-Ion-Implanted Steel

    Institute of Scientific and Technical Information of China (English)

    张通和; 吴瑜光; 刘安东; 张旭; 王晓妍

    2003-01-01

    The corrosion and pitting corrosion resistance of C+ Ti dual and C+Ti+C ternary implanted H13 steel were studied by using a multi-sweep cyclic voltammetry and a scanning electron microscope. The effects of phase formation on corrosion and pitting corrosion resistance were explored. The x-ray diffraction analysis shows that the nanometer-sized precipitate phases consist of compounds of Fe2 Ti, TiC, Fe2C and Fe3 C in dual implanted layer and even in ternary implanted layer. The passivation layer consists of these nanometer phases. It has been found that the corrosion and pitting corrosion resistance of dual and ternary implanted H13 steel are improved extremely. The corrosion resistance of ternary implanted layer is better than that of dual implantations and is enhanced with the increasing ion dose. When the ion dose of Ti is 6 × 1017/cm2 in the ternary implantation sample, the anodic peak current density is 95 times less than that of the H13 steel. The pitting corrosion potential of dual and ternary implantation samples is in the range from 55mV to 160mV which is much higher than that of the H13 steel. The phases against the corrosion and pitting corrosion are nanometer silkiness phases.

  19. Use of niobium to substitute vanadium in the steel for hot work AISI H3

    International Nuclear Information System (INIS)

    Branco, J.R.T.; Jesus, B.G. de

    1984-01-01

    Experimental results on austenitic grain size, quenching hardness and response to tempering measured on a H13 tool steel modified by niobium additions are described. It is shown that the replacement of 25 and 50% percent of the total vanadium by 0,05% of niobium does not change the response to quenching and tempering. (Author) [pt

  20. Versoening tussen leerders: Is parallelmediumskole die antwoord op die rassismeprobleem?

    OpenAIRE

    Du Plessis, Elize; Marais, Petro

    2017-01-01

    Die Suid-Afrikaanse Grondwet stel dit duidelik dat enige vorm van diskriminasie nie toegelaat mag word nie. In ons skole beteken dit dat elke leerder ʼn reg het op goeie opvoeding en ʼn veilige skoolomgewing. Die fokus van hierdie navorsing is gerig op bestaande parallelmediumskole. Die uiteindelike vraagstuk is dus hoe multikulturele onderwys bevorder word en hoe rassisme aangespreek kan word? As teoretiese raamwerk is Kohlsberg se kognitiewe ontwikkelingsbenadering en Whitehouse se univerele ...

  1. Die ontmaskering van die bose: Eksegetiese perspektiewe op ...

    African Journals Online (AJOL)

    p1243322

    2 Yarbro Collins (1983) bied tans nog die beste agtergrond vir 'n besinning oor geweld in ..... John's grammatical howlers are intentionally designed to alert listerners ..... 26 In die Nuwe Testament word Paul se snydende opmerking teenoor die Korintiërs as ..... rnt g0r`m nh8 ldfhrs`}m du sg}u fg}u + n2sh d/m sg>}} e`ql`jdh.

  2. Accurate defect die placement and nuisance defect reduction for reticle die-to-die inspections

    Science.gov (United States)

    Wen, Vincent; Huang, L. R.; Lin, C. J.; Tseng, Y. N.; Huang, W. H.; Tuo, Laurent C.; Wylie, Mark; Chen, Ellison; Wang, Elvik; Glasser, Joshua; Kelkar, Amrish; Wu, David

    2015-10-01

    Die-to-die reticle inspections are among the simplest and most sensitive reticle inspections because of the use of an identical-design neighboring-die for the reference image. However, this inspection mode can have two key disadvantages: (1) The location of the defect is indeterminate because it is unclear to the inspector whether the test or reference image is defective; and (2) nuisance and false defects from mask manufacturing noise and tool optical variation can limit the usable sensitivity. The use of a new sequencing approach for a die-to-die inspection can resolve these issues without any additional scan time, without sacrifice in sensitivity requirement, and with a manageable increase in computation load. In this paper we explore another approach for die-to-die inspections using a new method of defect processing and sequencing. Utilizing die-to-die double arbitration during defect detection has been proven through extensive testing to generate accurate placement of the defect in the correct die to ensure efficient defect disposition at the AIMS step. The use of this method maintained the required inspection sensitivity for mask quality as verified with programmed-defectmask qualification and then further validated with production masks comparing the current inspection approach to the new method. Furthermore, this approach can significantly reduce the total number of defects that need to be reviewed by essentially eliminating the nuisance and false defects that can result from a die-to-die inspection. This "double-win" will significantly reduce the effort in classifying a die-to-die inspection result and will lead to improved cycle times.

  3. Die pastorale sielkundige as diakonale pastor

    Directory of Open Access Journals (Sweden)

    A. J. Smuts

    1985-08-01

    Full Text Available In die bedieningspatroon van die Ned. Geref. Kerk het die pastorale sielkundige die afgelope aantal jare steeds meer op die voorgrond begin tree. Hy is egter 'n problematiese figuur, wie se identiteit van meer as een kant onder bespreking is. In ander lande, selfs in die VSA waar die kerk veel gebruik maak van die sielkunde, is dit moeilik om 'n presiese parallel vir hom te vind. Sowel binne as buite die kerk word hy deur sommige bevraagteken. Daarom is dit noodsaaklik om vanuit die teologie te kyk na die werk wat hy doen.

  4. Passivation condition of carbon steel in bentonite/sand mixture

    International Nuclear Information System (INIS)

    Taniguchi, Naoki; Kawakami, Susumu

    2002-03-01

    It is essential to understand the corrosion type of carbon steel under the repository conditions for the lifetime assessment of carbon steel overpack used for geological isolation of high-level radioactive waste. According to the previous study, carbon steel is hard to passivate in buffer material assuming a chemical condition range of groundwater in Japan. However, concrete support will be constructed around the overpack in the case of repository in the soft rock system and groundwater having a higher pH may infiltrate to buffer material. There is a possibility that the corrosion type of carbon steel will be influenced by the rise of the pH in groundwater. In this study, anodic polarization experiments were performed to understand the passivation condition of carbon steel in buffer material saturated with water contacted with concrete. An ordinary concrete an a low-alkalinity concrete were used in the experiment. The results of the experiments showed that the carbon steel can passivate under the condition that water having pH > 13 infiltrate to the buffer material assuming present property of buffer material. If the low-alkalinity concrete is selected as the support material, passivation can not occur on carbon steel overpack. The effect of the factors of buffer material such as dry density and mixing ratio of sand on the passivation of carbon steel was also studied. The results of the study showed that the present property of buffer material is enough to prevent passivation of carbon steel. (author)

  5. A low temperature aluminizing treatment of hot work tool steel

    Energy Technology Data Exchange (ETDEWEB)

    Matijevic, B., E-mail: bozidar.matijevic@fsb.hr [University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Zagreb (Croatia)

    2010-07-01

    Conventional aluminizing processes by pack cementation are typically carried out at elevated temperatures. A low temperature powder aluminizing technology was applied to hot tool steel H13. The aluminizing treating temperature was from 550 to 620°C. Effects of temperature and time on the microstructure and phase evolution were investigated. Also, the intermetallic layer thickness was measured in the aluminized layer of a steel substrate. The cross-sectional microstructures, the aluminized layer thickness and the oxide layer were studied. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), glow discharge optical spectroscopy (GDOS) were applied to observe the cross-sections and the distribution of elements. (author)

  6. A low temperature aluminizing treatment of hot work tool steel

    International Nuclear Information System (INIS)

    Matijevic, B.

    2010-01-01

    Conventional aluminizing processes by pack cementation are typically carried out at elevated temperatures. A low temperature powder aluminizing technology was applied to hot tool steel H13. The aluminizing treating temperature was from 550 to 620°C. Effects of temperature and time on the microstructure and phase evolution were investigated. Also, the intermetallic layer thickness was measured in the aluminized layer of a steel substrate. The cross-sectional microstructures, the aluminized layer thickness and the oxide layer were studied. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), glow discharge optical spectroscopy (GDOS) were applied to observe the cross-sections and the distribution of elements. (author)

  7. Digilanid C by die behandeling van hartlyers

    NARCIS (Netherlands)

    Snyman, Hendrik Willem

    1942-01-01

    In die voorafgaande word 'n literatuur studie oor die ontwikkeling en huidige stand van die chemie en farmakologie van die Digitalis purpurea en Digitalis lanata gegee, waarin spesiaal gelet word op die chemiese samestelling en farmakologiese aktiwiteit van die Digitalis lanata glikoside. Daarna

  8. HISTORIESE OORSIG VAN DIE ONTSTAAN EN ONTWIKKELING ...

    African Journals Online (AJOL)

    In 1933 belas Rykskanselier. Hitler vir. Goering, Minister van Lugvaart, in die geheim met die skepping van die Luftwaffe. Die basis in Rusland is gesluit en toekomstige vlieeniers is nou in die geheim na Italie waar hulle elke aspek van moderne oorlog- voering oefen en die Blitzkrieg-gedagte, deur op ondersteuning van 'n.

  9. EUNUG IN DIE ANTIEKE NABYE OOSTE

    African Journals Online (AJOL)

    rang. In Assiries beteken die woord “hoof-eunug”. Soos reeds vermeld (by 2), vorm die eunug 'n belangrike deel van die Assiriese burokrasie. Dokumente dui aan ... rang in die Babiloniese weermag, en so 'n amptenaar het saam met die rabsag ..... baie laat, in die inter-testamentêre periode, gebruik is vir 'n gekastreerde.

  10. Die Transition zur pflegenden Tochter

    Directory of Open Access Journals (Sweden)

    Dagmar Dräger

    2004-11-01

    Full Text Available Das Buch aus der Reihe „Studien zur Gesundheits- und Pflegewissenschaft“ beschreibt den theoretischen Hintergrund, das methodische Vorgehen und die Ergebnisse einer biografischen Untersuchung, die sich dem Übergang von der Tochter zur pflegenden Tochter widmete. Grundlage der Publikation ist die Dissertation (2002 der Autorin. Mit der Berücksichtigung biographischer und familiärer Hintergründe wird eine neue Perspektive in der Forschung zu pflegenden Angehörigen eingenommen.

  11. Maintaining Low Voiding Solder Die Attach for Power Die While Minimizing Die Tilt

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, Randy; Peterson, Kenneth A.

    2015-10-01

    This paper addresses work to minimize voiding and die tilt in solder attachment of a large power die, measuring 9.0 mm X 6.5 mm X 0.1 mm (0.354” x 0.256” x 0.004”), to a heat spreader. As demands for larger high power die continue, minimizing voiding and die tilt is of interest for improved die functionality, yield, manufacturability, and reliability. High-power die generate considerable heat, which is important to dissipate effectively through control of voiding under high thermal load areas of the die while maintaining a consistent bondline (minimizing die tilt). Voiding was measured using acoustic imaging and die tilt was measured using two different optical measurement systems. 80Au-20Sn solder reflow was achieved using a batch vacuum solder system with optimized fixturing. Minimizing die tilt proved to be the more difficult of the two product requirements to meet. Process development variables included tooling, weight and solder preform thickness.

  12. Tool steels

    DEFF Research Database (Denmark)

    Højerslev, C.

    2001-01-01

    On designing a tool steel, its composition and heat treatment parameters are chosen to provide a hardened and tempered martensitic matrix in which carbides are evenly distributed. In this condition the matrix has an optimum combination of hardness andtoughness, the primary carbides provide...... resistance against abrasive wear and secondary carbides (if any) increase the resistance against plastic deformation. Tool steels are alloyed with carbide forming elements (Typically: vanadium, tungsten, molybdenumand chromium) furthermore some steel types contains cobalt. Addition of alloying elements...... serves primarily two purpose (i) to improve the hardenabillity and (ii) to provide harder and thermally more stable carbides than cementite. Assuming proper heattreatment, the properties of a tool steel depends on the which alloying elements are added and their respective concentrations....

  13. Neurokognitiewe integrasie en die leerproses

    Directory of Open Access Journals (Sweden)

    Du Preez, Johan J.

    1991-12-01

    Full Text Available The purpose of this article, "Neuro-cognitive integration and the learning process'; is to find principles and strategies for the development of brain potential and the optimal integration of subject matter. Eight neuro-cognitive systems are identified and their importance to the integration of subject matter is emphasized. These systems are cortical energy, coding, planning and controlling, as well as the verbal sequential, non-verbal holistic, physical-motor, social effective and the subconscious. The relevant principles and strategies can serve as basis for mainstream and special education, guidance as well as psychotherapy. Die doe! met hierdie artikel is om beginsels en strategiee te vind om breinpotensiaal te ontsluit en leerstof optimaal te integreer. Aan die hand van 'n neurokognitiewe model word 'n aantal beginsels en strategiee bespreek en die verband met die leerproses word aangetoon. Agt neurokognitiewe sisteme is gei'dentifiseer en die belangrike rot wat dit speel ten opsigte van die integrasie van leerstof word beklemtoon. Genoemde sisteme sluit die volgende in: kortikale energie, kodering, beplanning en kontrolering, asook die verbaal-sekwensiele, nieverbaal-holistiese, fisiek-motoriese, sosio-affektiewe en die subbewuste. Genoemde beginsels en strategiee kan oak dien as grondslag vir hoofstroomonderwys, spesialiseringsonderwys, voorligting sowel as psigoterapie.

  14. Numerical optimization of die geometry in open die forging

    DEFF Research Database (Denmark)

    Christiansen, Peter; Hattel, Jesper Henri; Bay, Niels

    2013-01-01

    This paper deals with numerical optimization of open die forging of large metallic ingots made by casting implying risk of defects, e.g. central pores. Different material hardening properties and die geometries are combined in order to investigate, which geometry gives rise to maximum closure...

  15. die geskiedenis van die saw gedenkteken te fort klapperkop militere ...

    African Journals Online (AJOL)

    As gevolg van enige optrede, op enige plek, te enige tyd, deur enige vyand van die RSA of deur enige terroris(te), insurgent(e) of ander persoon of persone wat die RSA en sy volkere kwaadgesind is. h. Binne twee jaar (vyfhondred-en-dertig dae) nadat hy/sy met 'n ongeskiktheids- pensioen uit diens getree het agv siekte,.

  16. Die adversatiewe stelsel van bewyslewering en die beste belang ...

    African Journals Online (AJOL)

    MJM Venter

    weeg. Hierdie vraag word teen die agtergrond daarvan beoordeel dat veral dispute ..... restructuring family into the highly polarized positions of court-based dispute resolution.16. Talle alternatiewe om tekortkominge in die adversatiewe proses te ..... De Jong M "Mediation and Other Appropriate Forms of Alternative Dispute.

  17. Die teologiese debat: Die waarde of betekenis daarvan

    African Journals Online (AJOL)

    Ego vero hoc libro non contuli sed asservi et assero, ac penes nullum vo- lo esse iudicium, sed omnibus suadeo, ut praestent obsequium. (M Luther, De servo arbitrio, 1525). 1. INLEIDING. In ons dae is dit hoe mode om oor alles debat te voer. Een van die towerwoorde van ons tyd, veral op die politiek-staatkundige terrein, ...

  18. Die konteks vir die keuse van geriefsvoedsel van bepaalde ...

    African Journals Online (AJOL)

    Seugnet

    70. Die konteks vir die keuse van geriefsvoedsel van bepaalde beroepsvroue *. Martha Kok en Priscilla Botha. ABSTRACT. The purpose of this research is to understand and describe the context in which career women choose, purchase and use convenience food (CF). A person is rarely isolated from or unaffected by.

  19. Die vlugtige taal van vergeet: Die metafoor by Breyten Breytenbach ...

    African Journals Online (AJOL)

    From his first book of poetry, die ysterkoei moet sweet (“the iron cow must sweat”, 1964), till his most recent one, die windvanger (“the windcatcher”, 2007), metaphor has been a central means towards the creation of meaning for Breytenbach. This article will investigate the use of metaphor particularly in this recent book.

  20. Pylstertmotte (Lepidoptera: Sphingidae van die Nasionale Krugerwildtuin

    Directory of Open Access Journals (Sweden)

    M. A. van den Berg

    1975-07-01

    Full Text Available 'n Totaal van 42 spesies van pylstertmotte is in die Nasionale Krugerwildtuin versamel. Die bekendste hiervan is die patatrusper (Herse convolvuli (L en die dood-skedelmot (Acherontia atropos (L. Die volgende spesies wat versamel is, se voorkoms is nog nie voorheen vir die Republiek van Suid-Afrika aangemeld nie nl. Pemba flavillacea (Walk., Praedora plagiata (R. &J., Leptoclanis basalis (Walk., Polyptychus calcareus (R. &J., Polyptychus compar (R. &J., Nephele aequivalens (Walk., Nephele peneus (Cram., Hippotion roseipennis (Butler en Xenosphingia jansei (Jord.. Die verspreiding van Oligographa juniperi (Bsd. wat langs die kusgebiede van Natal en die Oos-Kaap aangetrefword, is op verskeie plekke in die Krugerwildtuin versamel.

  1. Statues Also Die

    Directory of Open Access Journals (Sweden)

    Pierre-Philippe Fraiture

    2016-10-01

    Full Text Available “African thinking,” “African thought,” and “African philosophy.” These phrases are often used indiscriminately to refer to intellectual activities in and/or about Africa. This large field, which sits at the crossroads between analytic philosophy, continental thought, political philosophy and even linguistics is apparently limitless in its ability to submit the object “Africa” to a multiplicity of disciplinary approaches. This absence of limits has far-reaching historical origins. Indeed it needs to be understood as a legacy of the period leading to African independence and to the context in which African philosophy emerged not so much as a discipline as a point of departure to think colonial strictures and the constraints of colonial modes of thinking. That the first (self-appointed exponents of African philosophy were Westerners speaks volumes. Placide Tempels but also some of his predecessors such as Paul Radin (Primitive Man as Philosopher, 1927 and Vernon Brelsford (Primitive Philosophy, 1935 were the first scholars to envisage this extension of philosophy into the realm of the African “primitive.” The material explored in this article – Statues Also Die (Marker, Resnais, and Cloquet, Bantu Philosophy (Tempels, The Cultural Unity of Negro Africa (Cheikh Anta Diop, and It For Others (Duncan Campbell - resonates with this initial gesture but also with the ambition on part of African philosophers such as VY Mudimbe to challenge the limits of a discipline shaped by late colonialism and then subsequently recaptured by ethnophilosophers. Statues Also Die is thus used here as a text to appraise the limitations of African philosophy at an early stage.  The term “stage,” however, is purely arbitrary and the work of African philosophers has since the 1950s often been absorbed by an effort to retrieve African philosophizing practices before, or away from, the colonial matrix. This activity has gained momentum and has been

  2. Die faktore gemeenskaplik aan die selfondersoekvraelys van Holland en die nuwe Suid-Afrikaanse beroepsbelangstellingsvraelys

    Directory of Open Access Journals (Sweden)

    C. Swanevelder

    1992-06-01

    Full Text Available The factors common to the Self Directed Search of Holland (SDS and the new South African Vocational Interest Inventory (SAVII. The new South African Vocational Interest Inventory was locally developed with the purpose to create a single vocational interest inventory for all population groups in the RSA. In this study the common factors underlying the SDS and the SAVII were determined with the aid of interbattery factor analysis. The results indicate that there are six common factors underlying the two instruments for both the standard nine boys and girls, and that these factors agree with the six factors built into the SDS by Holland. Opsomming Die nuwe Suid-Afrikaanse Beroepsbelangstellingsvraelys (SABBV is plaaslik ontwikkel met die doel om 'n enkele beroepsbelangstellingsvraelys vir alle bevolkingsgroepe binne die RSA, daar te stel. In hierdie studie is daar ondersoek ingestel na die gemeenskaplike faktore onderliggend aan die SABBV en die Selfondersoekvraelys (SOV van Holland met behulp van 'n interbatteryfaktorontleding. Daar is bevind dat daar ses gemeenskaplike faktore onderliggend aan die twee instrumente is vir sowel standerd nege seuns as dogters, en dat hierdie faktore ooreenstem met die ses faktore wat deur Holland in die SOV ingebou is.

  3. Awareness of Dying Preface

    Directory of Open Access Journals (Sweden)

    Barney G. Glaser, PhD, Hon. PhD

    2015-12-01

    Full Text Available Recently The New York Times reported: “VERY ILL CHILDREN TOLD OF DISEASE; Leukemia Patients at N.I.H. Not Shielded From Truth. . . . A child should always be told the truth, even when he has an incurable disease such as leukemia, according to two researchers who interviewed 51 children hospitalized at the National Cancer Institute, Bethesda, Maryland, for treat¬ment of leukemia.” This kind of news item reflects the growing concern among researchers and public about matters which touch on morality as much as on the technical aspects of medi¬cine. The rapidly increasing proportion of elderly people in the American population presents a range of personal and social questions; not the least is how they view their newly won longevity (often including anticipated years of chronic disease as well as their attitudes toward death. In consequence, many geriatric specialists are beginning to study American attitudes toward death, while others, spurred on by what seems a sense-less prolonging of life within hospital walls by medical tech¬nology run wild, are raising questions about death and dying in American life.

  4. Die Parlamentswahlen 2008 in Malaysia

    DEFF Research Database (Denmark)

    Reher, Stefanie; Knirsch, Thomas

    2008-01-01

    aus diversen Parteien bestehende Oppositionsbündnis erfuhr überraschend eine klare Stärkung. Während die aus der UMNO und 13 weiteren Koalitionären bestehende BN unter dem Motto „Sicherheit, Frieden, Wohlstand” für Premier Badawi warb, führten die Oppositionsparteien DAP, PAS und PRK – letztere unter...

  5. In diens van die Kompanjie

    African Journals Online (AJOL)

    was ook siektes WQl Jit onvoldoende of ondoel- treffende voeding, eentonige kos en ontoerei- kende geneesmiddels voortgespruit het, terwyl behoorlike versorging dikwels ontbreek he!. Doodsoorsake tydens die seereis het voartge- vloei uit ongelukke aan boord, beperkte ruimte vir die bemanning en geringe vars lug, ...

  6. Die Mythen von der Globalisierung

    DEFF Research Database (Denmark)

    Nell, Phillip; Schmitt, Jan; Decreton, Benoit

    2017-01-01

    Der Wissensstand über den Grad und die Art der Globalisierung ist viel niedriger als angenommen. Daraus entstehen Fehleinschätzungen.......Der Wissensstand über den Grad und die Art der Globalisierung ist viel niedriger als angenommen. Daraus entstehen Fehleinschätzungen....

  7. n hoofstuk in die (outo)biografie van die predikant (pastor?) 1 ...

    African Journals Online (AJOL)

    biografie van die dominee (pastor?), spreek om verskeie redes boekdele. Die gebruik van die onbepaalde lidwoord is eerstens 'n bevestiging dat die artikel slegs 'n verdere bydrae (hoofstuk) tot die bestaande en steeds voortgaande gesprek (boek) oor die biografie van die dominee is (Heitink 2001). Tweedens plaas ek ...

  8. die krag van simbole en rites in die liturgie 1. probleemstelling

    African Journals Online (AJOL)

    uitroepe vervang met die drie keer Kyrie eleison, die drie maal Christe eleison en die drie keer Kyrie eleison-uitroepe (Albrecht 1989:43). Op die lang duur het die uitroep dus heeltemal losgeraak van die gebede en het dit 'n selfstandige liturgiese element geword (Van Rongen. 1990:35). Die Reformasie met sy nadruk op ...

  9. Vanaf die Fermat-punte na die De Villiers-punte van ’n driehoek

    Directory of Open Access Journals (Sweden)

    Michael de Villiers

    2010-01-01

    Full Text Available Hierdie artikel beskryf die ontdekking van die sogenaamde De Villiers-punte van ’n driehoek die bewyse wat betrokke is, en trek die historiese oorsprong terug na die Fermat-punte van ’n driehoek, die swaartepunt van ’n driehoek, en ’n nuttige veralgemening van die Fermat-punte van ’n driehoek.

  10. Montessori-skole: die ander kant

    Directory of Open Access Journals (Sweden)

    Monica Viljoen

    1995-03-01

    Full Text Available Na aanleiding van die artikel “Die invloed van die New Age-beweging op die onderwysagenda van die toekoms” deur Lien van Niekerk en Corinne Meier van die Departement Historiese Opvoedkunde van Unisa (vgl. Koers, 59 (1 1994:69-84 wil ek graag ’n ander sy van Montessori-skole onder die aandag van Koers lesers bring.

  11. Mediamonitering in die bestuur van korporatiewe beeld

    OpenAIRE

    2012-01-01

    M.Comm. Die waarde van hierdie ondersoek hou verband met die bemarking van 'n onderneming en die handhawing van 'n mededingende voordeel deur die projektering van 'n positiewe beeld (Anon., 1995a:92; Bateman & Zeithaml, 1993:75; Caminiti, 1992:50; Kotler & Armstrong, 1991:240). Hierdie aspek neem toe in belangrikheid soos wat die besigheidsmilieu in Suid-Afrika verander, veral wat betref die toetrede van buitelandse maatskappye tot die Suid-Afrikaanse mark.

  12. Structural changes of radial forging die surface during service under thermo-mechanical fatigue

    International Nuclear Information System (INIS)

    Nematzadeh, Fardin; Akbarpour, Mohammad Reza; Kokabi, Amir Hosein; Sadrnezhaad, Seyed Khatiboleslam

    2009-01-01

    Radial forging is one of the modern open die forging techniques and has a wide application in producing machine parts. During operation at high temperatures, severe temperature change associated with mechanical loads and the resultant wearing of the die surface lead to intense variation in strain on the die surface. Therefore, under this operating condition, thermo-mechanical fatigue (TMF) occurs on the surface of the radial forging die. TMF decreases the life of the die severely. In the present research, different layers were deposited on a 1.2714 steel die by SMAW and GTAW, with a weld wire of UDIMET 520. The microstructure of the radial forging die surface was investigated during welding and service using an optical microscope and scanning electron microscope. The results revealed that, after welding, the structure of the radial forging die surface includes the γ matrix with a homogeneous distribution of fine semi-spherical carbides. The weld structure consisted mostly of columnar dendrites with low grain boundaries. Also, microstructural investigation of the die surface during operation showed that the weld structure of the die surface has remained without any considerable change. Only dendrites were deformed and broken. Moreover, grain boundaries of the dendrites were revealed during service.

  13. Minimum Requirements of Flagellation and Motility for Infection of Agrobacterium sp. Strain H13-3 by Flagellotropic Bacteriophage 7-7-1

    Science.gov (United States)

    Yen, Jiun Y.; Broadway, Katherine M.

    2012-01-01

    The flagellotropic phage 7-7-1 specifically adsorbs to Agrobacterium sp. strain H13-3 (formerly Rhizobium lupini H13-3) flagella for efficient host infection. The Agrobacterium sp. H13-3 flagellum is complex and consists of three flagellin proteins: the primary flagellin FlaA, which is essential for motility, and the secondary flagellins FlaB and FlaD, which have minor functions in motility. Using quantitative infectivity assays, we showed that absence of FlaD had no effect on phage infection, while absence of FlaB resulted in a 2.5-fold increase in infectivity. A flaA deletion strain, which produces straight and severely truncated flagella, experienced a significantly reduced infectivity, similar to that of a flaB flaD strain, which produces a low number of straight flagella. A strain lacking all three flagellin genes is phage resistant. In addition to flagellation, flagellar rotation is required for infection. A strain that is nonmotile due to an in-frame deletion in the gene encoding the motor component MotA is resistant to phage infection. We also generated two strains with point mutations in the motA gene resulting in replacement of the conserved charged residue Glu98, which is important for modulation of rotary speed. A change to the neutral Gln caused the flagellar motor to rotate at a constant high speed, allowing a 2.2-fold-enhanced infectivity. A change to the positively charged Lys caused a jiggly motility phenotype with very slow flagellar rotation, which significantly reduced the efficiency of infection. In conclusion, flagellar number and length, as well as speed of flagellar rotation, are important determinants for infection by phage 7-7-1. PMID:22865074

  14. Filosofiese tendense in die wordinggeskiedenis van ons verstaan van die fisiese natuur

    Directory of Open Access Journals (Sweden)

    D. F. M. Strauss

    2006-09-01

    Full Text Available Die ontstaan van ’n lang tradisie van natuurwetenskaplike denke is in antieke Griekeland te vind – die bakermat van die Westerse beskawing en die bron van geartikuleerde rasionele besinning. Die vroegste fases van die Griekse kultuur het reeds geboorte geskenk aan ’n teoretiese nadenke oor die heelal. Die Pythagoreërs is veral bekend vir hul klem op die verklaringskrag van getalsverhoudinge. In hul tese dat “alles getal is” het hulle egter slegs rasionale getalle (breuke erken en gevolglik uiteindelik vasgeloop in die ontdekking van irrasionale getalle wat tot die geometrisering van die Griekse wiskunde gelei het en tegelyk die bedding gevorm het van waaruit ’n magtige tradisie van ruimte-metafisika gegroei het wat die hele middeleeuse tydperk omspan het. Die vermeende statiese syn is in die mees ekstreme geval – die skool van Parmenides en die argumente van Zeno teen veelheid en beweging – tot in die uiteindelike antinomiese konsekwensies daarvan deurdink. Dit was egter eers die vroeg-moderne tyd – die voorgangers en nakomelinge van Galilei – wat naas getal en ruimte ’n waardering ontwikkel het vir die verklaringskrag van beweging (vergelyk die klassieke meganistiese wêreldbeeld van die heelal as ’n meganisme van stofdeeltjies in beweging. Maar ook hierdie meganistiese reduksie (waardeur alle fisiese verskynsels herlei is tot die beweging van al of niegelade massapunte sou uiteindelik misluk omdat dit nie van die onomkeerbaarheid van fisiese prosesse rekenskap kon gee nie. Gevolglik beliggaam eers die fisika van die 20ste eeu ’n erkenning van die deurslaggewend-stempelende rol van energie-werking (dus van die fisiese aspek in die aard van stoflike dinge en prosesse. Die artikel word afgesluit met ’n vlugtige verduideliking van die implikasies van die voorafgaande argumentasie vir ’n benadering van die misterie van die bestaan van materie.

  15. Energy Saving Melting and Revert Reduction Technology: Improved Die Casting Process to Preserve the Life of the Inserts

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam, PI; Xuejun Zhu, Sr. Research Associate

    2012-09-30

    The goal of this project was to study the combined effects of die design, proper internal cooling and efficient die lubricants on die life. The project targeted improvements in die casting insert life by: Optomized Die Design for Reduced Surface Temperature: The life of die casting dies is significantly shorter when the die is exposed to elevated temperature for significant periods of time. Any die operated under conditions leading to surface temperature in excess of 1050oF undergoes structural changes that reduce its strength. Optimized die design can improve die life significantly. This improvement can be accomplished by means of cooling lines, baffles and bubblers in the die. A key objective of the project was to establish criteria for the minimal distance of the cooling lines from the surface. This effort was supported with alloys and machining by BohlerUddeholm, Dunn Steel, HH Stark and Rex Buckeye. In plant testing and evaluation was conducted as in-kind cost share at St. Clair Die Casting. The Uddeholm Dievar steel evaluated in this program showed superior resistance to thermal fatigue resistance. Based on the experimental evidence, cooling lines could be placed as close as 0.5" from the surface. Die Life Extension by Optimized Die Lubrication: The life of die casting dies is affected by additions made to its surface with the proper lubricants. These lubricants will protect the surface from the considerable temperature peaks that occur when the molten melt enters the die. Dies will reach a significantly higher temperature without this lubricant being applied. The amount and type of the lubricant are critical variables in the die casting process. However, these lubricants must not corrode the die surface. This effort was supported with alloys and machining by BohlerUddeholm, Dunn Steel, HH Stark and Rex Buckeye. In plant testing and evaluation was conducted as in-kind cost share at St. Clair Die Casting. Chem- Trend participated in the program with die

  16. Tribological Behavior of Laser Textured Hot Stamping Dies

    Directory of Open Access Journals (Sweden)

    Andre Shihomatsu

    2016-01-01

    Full Text Available Hot stamping of high strength steels has been continuously developed in the automotive industry to improve mechanical properties and surface quality of stamped components. One of the main challenges faced by researchers and technicians is to improve stamping dies lifetime by reducing the wear caused by high pressures and temperatures present during the process. This paper analyzes the laser texturing of hot stamping dies and discusses how different surfaces textures influence the lubrication and wear mechanisms. To this purpose, experimental tests and numerical simulation were carried out to define the die region to be texturized and to characterize the textured surface topography before and after hot stamping tests with a 3D surface profilometer and scanning electron microscopy. Results showed that laser texturing influences the lubrication at the interface die-hot sheet and improves die lifetime. In this work, the best texture presented dimples with the highest diameter, depth, and spacing, with the surface topography and dimples morphology practically preserved after the hot stamping tests.

  17. Die identifisering van maatstawwe vir die navorsingsprestasie van akademici

    Directory of Open Access Journals (Sweden)

    H. A. Labuschagne

    1990-06-01

    Full Text Available Identification of criteria for academic research performance. At South African universities, the achievement of objectives is usually measured in terms of so-called "process criteria" (e.g. pass rates, instead of performance criteria which reflect the quality of academic personnel. Stimulated by the need to identify valid indices of research performance, as a component of academic performance, this study investigated the dimensionality of several criteria, identified from empirical and literature studies. It was found that various valid criteria could be represented by six constructs, viz.: the stature of the researcher as scientist; scientific contributions; enhancement of own profession; community development; participation in research projects; and giving advice to persons or institutions outside the university. Opsomming By Suid-Afrikaanse universiteite word doelwitbereiking gewoonlik aan die hand van sogenaamde "prosesmaat-stawwe" (bv. slaagsyfers in plaas van prestasiemaatstawwe wat die gehalte van akademiese personeel weerspieel, gemeet. Na aanleiding van 'n behoefte aan die identifisering van geldige rigtingwysers vir navorsingsprestasie as 'n komponent van akademiese prestasie, is daar ondersoek ingestel na die dimensionaliteit van verskillende maatstawwe wat vooraf deur middel van empiriese- en literatuurstudies geidentifiseer is. Daar is gevind dat verskeie geldige maatstawwe deur ses konstrukte verteenwoordig word, te wete: die statuur van die navorser as wetenskaplike, wetenskaplike bydraes, uitbouing van eie professie, gemeenskapsontwikkeling, deelname aan navorsingsprojekte en advieslewering aan persone of instellings buite die Universiteit.

  18. Vibrational spectra and structure of icosahedral anion of monocarba-closo-dodecaborane [CB11H12]- and its nido-derivative: [CB10H13]-

    International Nuclear Information System (INIS)

    Kononova, E.G.; Bukalov, S.S.; Lejtes, L.A.; Lysenko, K.A.; Ol'shevskaya, V.A.

    2003-01-01

    Raman and IR spectra of cesium salts of monocarborane anions [closo-CB 11 H 12 ] - and [nido-CB 10 H 13 ] - were recorded, assignment of frequencies being provided. Quantum-chemical calculation of geometry of the closo-polyhedrons [B 12 H 12 ] 2- and [CB 11 H 12 ] - along with that of frequencies and forms of normal vibrations of the latter was made. Comparison of structural and spectral characteristics in the series of isoelectronic closo-polyhedrons [B 12 H 12 ] 2- , [CB 11 H 12 ] - and p-C 2 B 10 H 12 , as well as those of the closo- and nido structures, was made [ru

  19. DEVELOPMENT OF THE DOPING MATRIX FOR CREATION OF THE BELORUSSIAN INSTRUMENTAL STEELS ON THE BASIS OF STEEL 70K(Y7A PRODUCED BY RUP “BMZ” (view and investigation

    Directory of Open Access Journals (Sweden)

    D. M. Kukuj

    2004-01-01

    Full Text Available Theoretical and practical aspects of production of the Belorussian instrumental steels on the base of the steel of type 70K are considered. The ways of working out of the alloy complex for receiving of the die steels in the conditions of RUP “BMZ” are shown.

  20. Die toepassing van die K3-model op die televisieteks Colour TV

    African Journals Online (AJOL)

    “OIL's approach to investigating the coloured market took place in the form of ethnographic research which ... communication strategies” (Botha 2010: 14). ... Op grond van die waarnemings, onderhoude en vraelyste het OIL tot die volgende ..... hold onto your nearest and dearest because this is going to be a kwaai mix bag.

  1. Steel alloys

    International Nuclear Information System (INIS)

    Bloom, E.E.; Stiegler, J.O.; Rowcliffe, A.F.; Leitnaker, J.M.

    1977-01-01

    The invention deals with a fuel element for fast breeder reactors. It consits essentially of a uranium oxide, nitride, or carbide or a mixture of these fuels with a plutonium or thorium oxide, nitride, or carbide. The fuel elements are coated with an austenitic stainless steel alloy. Inside the fuel elements, vacancies or small cavities are produced by neutron effects which causes the steel coating to swell. According to the invention, swelling is prevented by a modification of type 304, 316, 321, or 12 K 72HV commercial steels. They consist mainly of Fe, Cr, and Ni in a ratio determined by a temary diagram. They may also contain 1.8 to 2.3% by weight of Mo and a fraction of Si (0.7 to 2% by weight) and Ti(0.10 to 0.5% by weight) to prevent cavity formation. They are structurally modified by cold working. (IHOE) [de

  2. Die kliniese kindersielkundige as diagnostikus1

    Directory of Open Access Journals (Sweden)

    D. J. W. Strümpfer

    1961-03-01

    Full Text Available Die benaming „Kliniese Kindersielkunde” is nog onbekend en gevolglik betreklik onbemind. Dit is in 1951 die eerste keer gebruik. Die werk van die Kliniese Kindersielkunde is egter so oud as die werk van die algemene Kliniese Sielkunde, waarvan die geskiedenis gewoonlik teruggevoer word tot die begin van sielkundige toetsing vroeg in die tagtigerjare. Tot ’n aansienlike mate is hierdie vroeë werk op kinders uitgevoer, bv. dié van Galton en later die van Binet en Simon. Witmer het in 1896 die eerste sielkundige kliniek geopen en het ook die term „Kliniese Sielkunde” ingevoer; die meerderheid van sy pasiënte was egter ook kinders. Tot voor die Tweede Wêreldoorlog was klinies-sielkundige werk hoofsaaklik op kinders toegespits. Sedertdien het die kliniese sielkundige tot ’n belangrike mate toegetree tot die gebied van die diagnose en terapie van psigiese afwykings by volwassenes, tot so ’n mate dat in die gedagtes en geskrifte van baie werkers die terrein van die Kliniese Sielkunde byna tot werk met volwassenes beperk word.

  3. James Henry Greathead en die Londense Moltrein

    Directory of Open Access Journals (Sweden)

    Laurence Wright

    2017-07-01

    Full Text Available Die artikel ondersoek die oorsprong en vroeë geskiedenis van die toestel genaamd die ‘Greathead Skild’, ‘n belangrike nuwigheid in Viktoriaanse ingenieurwetenskap, wat van deurslaggewende belang was in die konstruksie van die Londense Moltrein. Die doel is om die basis te ontleed waarop, baie jare later, ‘n Suid-Afrikaanse ingenieur wye openbare erkenning in die vorm van ‘n standbeeld vir die ‘ontwerp’ van die Skild geniet het. Uit die perspektief van kulturele studies beskou, hoe moet ons uitvinding verstaan, gegewe dat ander briljante ingenieurs ook betrokke was? Hierdie vraag word ontleed met die gebruik van die konsep ‘extelligence’ (Stewart and Cohen 1997, in samehang met ander kontemporêre en geskiedkundige weergawes, insluitend Greathead se eie rekord van sy prestasies in die verrigtinge van die Instituut van Siviele Ingenieurs en voorgelê in The City and South London Railway (1896, onder redaksie van James Forrest. Hierdie artikel is die eerste keer as referaat aangebied by die konferensie oor ‘Nuuthede en Innovasie in die Negentiende Eeu’ aan die Noordwes-Universiteit, Mei 2016.

  4. DIE NAAM “NEDERDUITSE GEREFORMEERDE KERK”

    African Journals Online (AJOL)

    P.J. Strauss. DIE NAAM “NEDERDUITSE. GEREFORMEERDE KERK”. ABSTRACT. An investigation into the name of the Dutch Reformed Church (DRC) reveals that it is a reformed church in the ... P.J. Strauss, Fakulteit Teologie, Universiteit van die Vrystaat, Suid‑Afrika. ..... Dit is so omdat die staat en sy howe die reg in die ...

  5. Abstraksie en veralgemening in die Wiskunde

    Directory of Open Access Journals (Sweden)

    B.C. Strydom

    1967-03-01

    Full Text Available Wanneer ek tot u spreek oor abstraksie en veralgemening in die Wiskunde, wil ek u aandag vestig op die belangrikheid daarvaan vir die Wiskunde, maar u terselfdertyd daarop wys dat die wiskundige hom nie langs hierdie weg heeltemal van die werklikheid kan losmaak nie.

  6. Die Dankesrede bei der Preisverleihung

    Directory of Open Access Journals (Sweden)

    Elenmari Pletikos Olof

    2012-12-01

    Full Text Available Festliche Preisverleihungen sind Gelegenheiten, bei denen von den Preisträgerneine kurze Rede erwartet wird. Obwohl die Dankesrede eine kleinere Randgattung innerhalb des epideiktischen Genres ist, steht sie im Mittelpunkt des Ereignisses. Rhetorikhandbücher geben zahlreiche Ratschläge, wie eine gute Festrede vorbereitet werden soll, um zu unterhalten, zu bewegen und zu belehren. Ziel dieser Untersuchung ist es festzustellen, welche Eigenschaften der Dankesrede die Zuhörer als erwünscht oder unerwünscht wahrnehmen und welche Charakteristika am meisten zur Qualität festlicher Dankesreden beitragen. Das Korpus der gesprochenen Texte bilden 30 Dankesreden anlässlich kroatischer Preisverleihungen in den Bereichen Schauspiel, Sport, Musik, Fernsehen, Literatur und Wirtschaft. Die Audio-Aufnahmen der Dankesreden wurden einer Gruppe von Hörern zur Bewertung in folgenden Kategorien vorgelegt: interessant, geistreich, hoher Sprachstil, feierlich, emotiv, persönlich, originell, bescheiden, vorbereitet und spontan. Zusätzlich wurde zu jeder Rede die offene Frage gestellt, was dem Zuhörer an der Rede gefallen oder nicht gefallen habe. Die Resultate der Perzeptionsanalye lassen erkennen, dass die Interessantheit einer Rede mit der Eigenschaft des Geistreichen, des Originellen, des Emotionalen und des Persönlichen in Verbindung gebracht wird und die Eigenschaft des Festlichen im Wesentlichen nur mit dem hohen Sprachstil und der Vorbereitetheit des Textes korreliert. Einige Eigenschaften können sowohl erwünscht als auch unerwünscht sein, z. B. Dialekt, Persönliches und Kürze. Die besten Dankesreden haben Eigenschaften, die im Grunde schwer miteinander zu verbinden sind: Einerseits soll der Text vorbereitet sein (hoher Stil, Wortwahl, Figuren, Originalität der Geschichte, Humor, andererseits wird bei der Ausführung Spontaneität (Aufrichtigkeit, Emotionalität, Persönlichkeit erwartet.

  7. Author: T Bekker DIE MOONTLIKE REGSHERVORMING VAN DIE ...

    African Journals Online (AJOL)

    RV

    So ver terug as die vroeë twintigste eeu het die Appèlhof in Cassiem v Standard. Bank of SA Ltd,1 .... 838; Capital Building Society v De Jager 1963 3 SA 381 (T); Smit v Walles 1985 2 SA 189 (T). 196-198. 18 ...... moeilik kon regverdig.97. Ons howe het tot op hede gehuiwer om 'n algemene plig van goeie trou ten aansien.

  8. High pressure die casting of Fe-based metallic glass

    Science.gov (United States)

    Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András

    2016-01-01

    Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications. PMID:27725780

  9. High pressure die casting of Fe-based metallic glass.

    Science.gov (United States)

    Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András

    2016-10-11

    Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications.

  10. High pressure die casting of Fe-based metallic glass

    Science.gov (United States)

    Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András

    2016-10-01

    Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications.

  11. Quantenfische die Stringtheorie und die Suche nach Weltformel

    CERN Document Server

    Lüst, Dieter

    2011-01-01

    Lässt sich das Verhalten aller Dinge, von den kleinsten Teilchen bis zum Universum, einheitlich beschreiben? Der heißeste Kandidat für die Entwicklung einer Weltformel, die alle physikalischen Phänomene erklären kann, ist die Stringtheorie. Sollte sie sich als richtig erweisen, so würde das unser Verständnis über den Ursprung der Naturgesetze dramatisch verändern. Denn das von uns beobachtete Universum wäre dann vermutlich eine winzige Blase in einem viel größeren Gebilde, dem Multiversum. Um die Stringtheorie und die Idee des Multiversums plausibel zu machen, greift der international bekannte theoretische Physiker Dieter Lüst auf ein Modell zurück: das Leben von Fischen in einem Teich. Eines Tages gelingt es den Fischen, die kleinsten Teilchen zu identifizieren, aus denen alles im Fischteich besteht - eingeschlossen sie selbst. Sie nennen diese Urbausteine Quantenfische, da ihr Verhalten nahelegt, dass sie auch eine Art von Lebewesen sind. Doch der ersten folgt eine weitere Entdeckung der Fisch...

  12. Die rol van persoonlikheidstrekke in die weerstand teen stres

    Directory of Open Access Journals (Sweden)

    Sonja V. R. van Oudtshoorn

    1988-05-01

    Full Text Available The role of personality characteristics in resistance to stress: A study was conducted to establish whether certain personality characteristics contribute to resistance to stress. Rescue brigadesmen, performing dangerous rescue operations in the goldmining industry, served as basis for the study. The sample consisted of 63 current, 56 ex- and 50 non-brigadesmen. Results indicate that brigadesmen, on the basis of their personality structure, are better equipped to cope with stress. Scores on the 16PF show that they have a lower level of interpersonal anxiety (Factor Q4 and that they are more practical (Factor I, emotionally stable (Factor C, and conscientious (Factor G. These findings support existing knowledge of the 16PF. Opsomming Ten einde vas te stel ofdaar sekere persoonlikheidstrekke bestaan wat bydra tot weerstand teen stres, is 'n studie uitgevoer met reddingspanlede, wat lewensgevaarlike reddingsdiens in die goudmynbedryf verrig, as ondersoekgroep. Die streekproefhet uit 63 huidige, 56 oud-reddingspanlede en 50 amptenare, wat nog nooit aan die span behoort het nie, bestaan. Dit blyk dat reddingspanlede, op grond van hulle persoonlikheidstruktuur, beter toegerus is om stres te hanteer. Tellings op die 16PF toon dat hulle oor 'n laervlakvan interpersoonlike angs beskik, (Faktor Q4, dat hulle meer prakties (Faktor I, emosioneel stabiel (Faktor C en konsensieus is (Faktor G. Hierdie bevindinge sluit aan by die reeds bestaande kennis oor die 16PF.

  13. Materials Processing Research and Development

    Science.gov (United States)

    2001-11-01

    interface between a Ti-6Al-4V workpiece and H13 tool steel die for various combinations of lubricants and workpiece-die temperatures. The ring test was...attaching a type-K thermocouple to the sample. The samples at 400 °C were heated using band heaters attached to H13 tool steel dies, with the...Ring Tests The ring tests were performed on a 200 kip servo-hydraulic press between H13 tool steel dies heated to the prescribed die temperatures of

  14. Hegelian Steel

    DEFF Research Database (Denmark)

    Kjær, Poul F.

    2015-01-01

    Even in our globalized world the notion of national economies remain incredibly strong, just as a considerable part of the literature on transnational governance and globalization continue to rely on a zero-sum perspective concerning the relationship between the national and the transnational. De...... of the European steel industry....

  15. Nuwe patogene in die voedselbedryf

    Directory of Open Access Journals (Sweden)

    M. M. Ehlers

    1996-07-01

    Full Text Available ’n “Nuwe generasie” voedselpatogene het die afgelope jare hul verskyning gemaak en kan 'n ernstige gevaar vir die voedselbedryf inhou. Hierdie organismes is uiters aanpasbaar en bestaande voedselprosesseringstegnieke, veral die verkoeling van voedsel, is nie altyd volkome effektief om hul groei te voorkom nie. Clostridium botulinum tipe E, enterotoksigeniese Eschsrichia coli. Listeria monocytogenes en Aeromonas hydrophila is in staat om in voedsel by 5 °C te groei. Campylobacter jejuni en Brucella kan weer by 5 °C oorleef en 'n derde groep organismes, naamlik Salmonella, Staphylococcus aureus, Vibrio parahaemolyticus en Vibrio vulnificus kan by temperature tussen 5 °C en 12 °C groei en hul teenwoordigheid is ’n aanduiding dat die koueketting verbreek is.

  16. Die Last mit der Lust

    Directory of Open Access Journals (Sweden)

    Lutz Sauerteig

    2004-03-01

    Full Text Available Robert Jütte legt mit Lust ohne Last eine umfassende, allgemeinverständliche und spannend zu lesende Geschichte der Empfängnisverhütung von der Antike bis in die unmittelbare Gegenwart vor.

  17. pastorale begeleiding aan die persoon met dissosiatiewe ...

    African Journals Online (AJOL)

    psychological or pastoral by nature. Effective assistance to the person ... INLEIDING. Volgens die kriteria in die DSM-IV2 (Diagnostic and statistical manual of mental disorders, 4th edition) van die APA (American Psychiatric. Association 1995) ...

  18. The efficient ones; Die Leistungsfaehigen

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2000-06-01

    The increase of output of a solar system where vacuum tube collectors replace flatbed collectors is difficult to calculate exactly. The formula for the calculation of efficiency is the basis of such calculations. Due to evacuation and better insulation the heat loss of vacuum tube collectors is smaller than that of flatbed collectors. This is also evident in the fact that the efficiency curve decreases less steeply as the temperature difference increases. Efficiency remains relatively high. Up to now vacuum tube collectors have been a niche product but more and more companies now sell these efficient collectors.(orig.). [German] Wie stark sich die Leistung der Solaranlage verbessert, wenn man Vakuumroehrenkollektoren (VRK) statt Flachkollektoren einsetzt, laesst sich nur schwer berechnen. Grundlage ist stets die Wirkungsgradformel. Aufgrund der Evakuierung und dadurch besseren Isolierung weisen die VRK deutlich geringere Waermeverluste auf als Flachkollektoren. Dies drueckt sich auch dadurch aus, dass die Wirkungsgradkurve mit wachsender Temperaturdifferenz {delta}{theta} deutlich flacher abfaellt. Der Wirkungsgrad bleibt relativ hoch. Als Hightech-Produkt hatte der Vakuumroehrenkollektor bisher eine typische Marktnische besetzt. Doch immer mehr Anbieter entscheiden sich fuer die Vermarktung dieser leistungsfaehigen Kollektoren. (orig.)

  19. Uitdagings in die onderrig van evolusie in die lewenswetenskappeklaskamer

    Directory of Open Access Journals (Sweden)

    Josef J. de Beer

    2013-02-01

    Full Text Available In hierdie artikel skryf die outeurs oor navorsing wat hulle gedoen het oor onderwysers se siening van die onderrig van evolusie, wat in 2008 as ’n tema in lewenswetenskappe in Suid-Afrikaanse skole ingesluit is. Hierdie vernuwing in die kurrikulum is met gemengde reaksies begroet. Terwyl sommige onderwysers dit met entoesiasme onderrig, is baie gekant teen die onderrig van evolusie. Die artikel is gebaseer op ’n navorsingsprojek waarby 255 onderwysers betrek is. Vraelyste is gebruik om kwalitatiewe data, wat vir diskoers ontleed is, in te samel. Die diskoers van die onderwysers het getoon dat ’n groot getal van hulle nie hul onderrigopdrag kan versoen met hul geloof nie en konsepte oor evolusie as ‘feite’ verduidelik, maar seker maak dat evolusie as ’n teorie gediskrediteer word. Dit het verreikende implikasies vir sowel onderwyseropleiding as kurrikulumontwikkeling. Konseptuele veranderingsteorie word as ’n lens gebruik om na hierdie problematiek te kyk. Challenges in the teaching of evolution in the life sciences classroom. In this article the authors report on research that was conducted about teachers’ views on evolution, which was introduced as a theme in the school life sciences curriculum in 2008. This innovation in the curriculum has been met with mixed reactions. Whereas some teachers embrace this new theme, many teachers are opposed to the teaching of evolution. The article reports on an inquiry that was conducted amongst 255 teachers and in which survey questionnaires were used to collect qualitative data, which was analysed for its discourse. The discourse of the teachers shows that many of them cannot reconcile their religious faith with their teaching and that they may teach the ‘facts’ of evolution, but make sure that they discredit evolution as a theory. This raises serious concerns about teacher education and curriculum development. The authors examine these issues through the lens of conceptual change

  20. die kasteel••de goede hoop" (1921.1923): die verhaal van in ...

    African Journals Online (AJOL)

    3. TWEE. KOMITEE-VERGADERINGS. BESLUITE a. Doel en samestelling van die komitee. Op 12 Desember 1921 stuur die Sekretans yap Verdediging uitnodigings aan sekere amptelike instansies en ander behingstd1endes waarin hy die redes vir die wenslikheid van 'n komitee en die werksaamhede uitecnsit en die ge-.

  1. Chrístologie: Die historiese Jesus en die kerugmatiese Christus by ...

    African Journals Online (AJOL)

    dige Here van sy kerk. Die Christelike teologie en die kerk het dus nie 'n ander oprsprong as wat die Christologiese belydenis van die oer-Christendom het nie, naamlik die paasgebeure. Schmithals (1972b:77) wil kerk en teologie aanmoedig om hierdie oorsprong in gedagte te hou en om goed te besef dat die Christus-.

  2. PROF DR FELIX V. lATEGAN: Die Boer se Roer. Die Groot ...

    African Journals Online (AJOL)

    PROF DR FELIX V. lATEGAN: Die Boer se. Roer. Die Groot Geweerboek van Suid-. Afrika. Tafelberg. Uitgewers. Kaapstad, pp. 209, bibliografie, register. Sonder die Boer en sy roer is die geskiede:lis van ons land feitlik ondenkbc:wr en dit is clan ook vo/kome juis gesien dat die skrywer van hierdie baanbrekerswerk die ...

  3. Die Energiesicherheit Europas in Bezug auf Erdgas und die Auswirkungen einer Kartellbildung im Gassektor

    OpenAIRE

    Krämer, Luis-Martín

    2011-01-01

    Die Dissertation untersucht die aktuelle Sicherheit der europaeischen Erdgasversorgung. Sie beruecksichtigt zudem die moeglichen Auswirkungen einer Kartellbildung auf die europaeische Gasversorgungssicherheit. Die Arbeit besteht aus einer detaillierten empirischen Studie und darauf aufbauender Szenarioanalyse. Hierzu wird auf den Interdependenzansatz von Robert O. Keohane und Joseph Nye zurueckgegriffen. Zur Darstellung des komplexen Themenbereichs wird auf die Darstellungspraxis der Dichten ...

  4. Paulus as vredemaker. Oor die resepsie van die Brief aan Filemon ...

    African Journals Online (AJOL)

    7 Jul 2015 ... Inleiding. Die woord 'vrede' kom net een maal in die Filemonbrief voor, en wel in die aanhef van die brief. Kommentatore merk egter gereeld op dat 'n mens nie daaruit moet aflei dat dié begrip onbelangrik vir die verstaan van die brief is nie. Om een voorbeeld te noem: Barth en Blanke. (2002) skryf as volg:.

  5. Die berekening van vloeiing in ’n roterende annulus deur die metode van kunsmatige saamdrukbaarheid

    Directory of Open Access Journals (Sweden)

    H. Grobler

    1987-03-01

    Full Text Available Die vloeiing van ’n onsaamdrukbare, viskeuse vloeier word ondersoek aan die hand van die numeriese oplossing van die gediskretiseerde Navier-Stokes- en kontinuiteitsbeheervergelykings. In die besonder word vloeiing in ’n annulus bestaande uit twee koaksiale silinders wat elk ten opsigte van die ander kan roteer, en met ’n voorgeskrewe drukval oor die lengte van die silinder, beskou. Die oplossings word bereken deur die toepassing van Chorin se metode van kunsmatige saamdrukbaarheid, waarin die tydonafhanklike beheervergelykings getransformeer word na tydafhanklike hulpvergelykings deur die invoering van ’n kunsmatige toestandsvergelyking. Die oplossing van die hulpvergelykings konvergeer na ’n stasionêre oplossing, wat ooreenstem met die oplossing van die oorspronklike tydonafhanklike beheervergelykings. Die gedrag van die vloeier, wanneer ten voile ontwikkelde laminêre vloeiing bereik word, is met sukses bereken. ’n Eenvoudige model vir die bepaling van ontwikkeling van vloeiing langs die annulus vir enige gegewe invloeisnelheidsprofiel word voorgestel. Die berekende resultate stem ooreen met die resultate wat uit die fisika van die probleem verwag word.

  6. Problems in steel industry for power engineering

    International Nuclear Information System (INIS)

    Dolbenko, E.T.; Kryanin, I.R.

    1979-01-01

    The main problems of steel industry in power engineering are considered. The effect of charge materials upon steel quality is analyzed. Radical dicision of the problem is the ensurance of power engineering plants with high quality original charge materials, which are quite pure according to impurities such as: iron melted from metallized charge or prereduced pellets. The usage of such materials considerably improves the complex of technological and service properties and structure of large responsible products: vessels of the reactor core, especially large shafts and others. For the most responsible power engineering dies it is necessary to smelt steel of 150-200 tons and above. The main direction of steel melting industry is quality steel melting in large 150-200 tons arc furnaces which are equipped with magnetic stirrer installations. It is marked that the branch of power engineering is equipped with unique installations of out-of-furnace steel refining. It is shown that further increase in the metal quality is possible when vacuum and electroslag technique of melting is used. It permits to reduce considerably the amount of sulphur, gases, nonmetallic inclusions, to increase the metal density, to remove zonal segregation in large steel ingots. The main problem in the field of usage of material, produced by new melting methods is the expansion of the product nomenclature and the development of technical conditions, reflecting the increase in material properties as a result of new technique application. Importance of development and introduction of new automation and testing methods in metallurgical processes is marked

  7. Die kritiek van tradisie en die tradisie van kritiek in die Geesteswetenskappe. 'n Rekonstruksie van die debat tussen Habermas en Gadamer

    OpenAIRE

    Duvenage, Pieter

    2013-01-01

    In hierdie bydrae word die bekende debat (1967-1971) tussen Jürgen Habermas en Hans-Georg Gadamer gerekonstrueer. Die debat word hier in noue samehang met die kwessie van die geesteswetenskappe gelees. Die bydrae val in vier dele uiteen. In die eerste afdeling word Habermas se opening tot die debat in vyf onderafdelings uiteengesit. Dit gaan hier oor Gadamer se verdediging van tradisie en Habermas se kritiek op die begrip (1.1). In antwoord op Gadamer se begrip van tradisie ontwerp Habermas s...

  8. Enkele opmerkings oor die intrinsieke waarde van die Latynse teks van Kodeks Bezae as herstelbron vir die Griekse teks van die Nuwe Testament

    Directory of Open Access Journals (Sweden)

    G. J.C. Jordaan

    1985-05-01

    Full Text Available Een van die belangrikste oud-Latynse vertalings word gevind in Kodeks Bezae, ’n vyfde-eeuse manuskrip van die vier Evangelies. Kodeks Bezae bevat ’n Griekse teks (D en ’n Latynse teks (d van die Evangelies langs mekaar, die Latynse teks in ’n lettertipe wat baie aan die Griekse majuskelskrif herinner. Wat hierdie dokument so merkwaardig maak, is die feit dat dit die enigste manuskrip is wat ’n Griekse Evangelie-teks uit die Westerse teksfamilie bevat.

  9. An overview of high thermal conductive hot press forming die material development

    Directory of Open Access Journals (Sweden)

    A.R. Zulhishamuddin

    2015-12-01

    Full Text Available Most of the automotive industries are using high strength steel components, which are produced via hot press forming process. This process requires die material with high thermal conductivity that increases cooling rate during simultaneous quenching and forming stage. Due to the benefit of high quenching rate, thermal conductive die materials were produced by adding carbide former elements. This paper presents an overview of the modification of alloying elements in tool steel for high thermal conductivity properties by transition metal elements addition. Different types of manufacturing processes involved in producing high thermal conductive materials were discussed. Methods reported were powder metallurgy hot press, direct metal deposition, selective laser melting, direct metal laser sintering and spray forming. Elements likes manganese, nickel, molybdenum, tungsten and chromium were proven to increase thermal conductivity properties. Thermal conductivity properties resulted from carbide network presence in the steel microstructure. To develop feasible and low cost hot press forming die material, casting of Fe-based alloy with carbide former composition can be an option. Current thermal conductivity properties of hot press forming die material range between 25 and 66 W/m.K. The wide range of thermal conductivity varies the mechanical properties of the resulting components and lifetime of HPF dies.

  10. Die gebruik van die mite in Die werfbobbejaan van Alexander Strachan

    Directory of Open Access Journals (Sweden)

    E. M.M. Klopper

    1996-05-01

    Full Text Available The use of myths in Die werfbobbejaan by Alexander Strachan This article focuses on the rote of Zulu myths in Alexander Strachan’s novel Die werfbobbejaan. It lakes as point of departure sources on mythology like Cuddon (1991, Baldick (1990, Grimal (1969, Levi-Strauss (1979 and Jung (1969. Die werfbobbejaan essentially recounts the story of a man (the adventurer, the academic, the writer, the hunter who also is the central character in Strachan's two preceding novels. Die werfbobbejaan focuses on the completion of an individuation process in the life of the central character, a process already begun in the preceding two novels and which in this novel finally culminates in the confrontation between hunter and baboon. The completion of this process is facilitated by the African milieu of Zululand where people give meaning to their existence by means of myths, and where no distinction is made between the mythic and rational modes of experiencing reality.

  11. (C6H13N)2BiI5: A One-Dimensional Lead-Free Perovskite-Derivative Photoconductive Light Absorber.

    Science.gov (United States)

    Zhang, Weichuan; Tao, Kewen; Ji, Chengmin; Sun, Zhihua; Han, Shiguo; Zhang, Jing; Wu, Zhenyue; Luo, Junhua

    2018-04-16

    Lead-free organic-inorganic hybrid perovskites have recently attracted intense interest as environmentally friendly, low-cost, chemically stable light absorbers. Here, we reported a new one-dimensional (1D) zigzag chainlike light-absorbing hybrid material of (C 6 H 13 N) 2 BiI 5 , in which the corner-sharing octahedral bismuth halide chains are surrounded by organic cations of tetramethylpiperidinium. This unique zigzag 1D hybrid perovskite-derivative material shows a narrow direct band gap of 2.02 eV and long-lived photoluminescence, which is encouraging for optoelectronic applications. Importantly, it behaves as a typical semiconducting material and displays obvious photoresponse in the visible-light range. This work opens a potential pathway for the further application of 1D lead-free hybrids.

  12. Structure and equilibria of Ca 2+-complexes of glucose and sorbitol from multinuclear ( 1H, 13C and 43Ca) NMR measurements supplemented with molecular modelling calculations

    Science.gov (United States)

    Pallagi, A.; Dudás, Cs.; Csendes, Z.; Forgó, P.; Pálinkó, I.; Sipos, P.

    2011-05-01

    Ca 2+-complexation of D-glucose and D-sorbitol have been investigated with the aid of multinuclear ( 1H, 13C and 43Ca) NMR spectroscopy and ab initio quantum chemical calculations. Formation constants of the forming 1:1 complexes have been estimated from one-dimensional 13C NMR spectra obtained at constant ionic strength (1 M NaCl). Binding sites were identified from 2D 1H- 43Ca NMR spectra. 2D NMR measurements and ab initio calculations indicated that Ca 2+ ions were bound in a tridentate manner via the glycosidic OH, the ethereal oxygen in the ring and the OH on the terminal carbon for the α- and β-anomers of glucose and for sorbitol simultaneous binding of four hydroxide moieties (C1, C2, C4 and C6) was suggested.

  13. Die rol van die onderwys in die handhawing en uitbouing van ons volkskultuur

    Directory of Open Access Journals (Sweden)

    G.J. Jordaan

    1970-03-01

    Full Text Available Op die oog af lyk dit ’n baie maklike onderwerp, maar hoe meer 'n mens daaroor nadink hoe ingewikkelder en omvangryker word die implikasies wat verband hou. Dit is veral so omdat dit hier voor alles gaan om eerste fundamentele uitgangspunte, dit wil sê, om lewens- en wêreldbeskouing. Dit geld van albei komponente — van onderwys sowel as van kultuur.

  14. Die vraag na ’n nuwe belydenisskrif

    Directory of Open Access Journals (Sweden)

    J. H. van Wyk

    1974-05-01

    Full Text Available Die mees bekende reformatoriese belydenisskrifte dateer uit die sestiende en sewentiende eeue (E 16—17 en is dus almal 300 tot 400 jaar oud: Die Galliese Konfessie 1559, die Nederlandse Geloofsbelydenis 1561, die Heidelbergse Kategismus 1563, die 39 Articles 1563, die Tweede Helvietiese Konfessie 1566, die Dordtse Leerreëls 1619, die Westminsterse Konfessie 1646.

  15. as by die huisbesoek. HP WOLMARANS. PROF. DR. SP ...

    African Journals Online (AJOL)

    Test

    van 'n evangeüedienaar wat alles fei! gehad het vir die werk en werk kring waartoe God hom geroep het. Hy is dan ook werklik die eerste grondlegger van die gemeente in Zoutpansberg en die man wat dit opgewerk het. Die geskiedenis van Hofmeyer is die geskiedenis van die kerk- vereniging en die redes waarom die ...

  16. Die krisis van ongeloof in Numeri 13-14

    African Journals Online (AJOL)

    Die ver- haal gebruik die aanloklikheid van die land as 'n submotief om 'n groter drama uit te beeld: die konflik tussen Israel en sy God. ISSN 0259 9422 ... In aansluiting by Eksodus 34 laat die liefde en trou van die Here aan Horn die ...... langs die weg van die tema van veertig jaar dat 'de hoofdstukken 13-14 een sleutel-.

  17. Wear mechanisms of Al2O3/TiC/Mo/Ni ceramic wire-drawing dies

    International Nuclear Information System (INIS)

    Deng Jianxin; Yang Xuefeng; Wang Jinghai

    2006-01-01

    Al 2 O 3 /TiC/Mo/Ni ceramic composites were produced by hot-pressing for the use of wire drawing dies. The fundamental properties of these ceramic die materials were examined. Wire drawing tests were carried out on the 65Mn steel wire with these ceramic dies. Finite element method (FEM) was used as a means of numerically evaluating stress and its distribution inside the ceramic drawing dies. Worn bore surfaces of the ceramic drawing dies were examined by scanning electron microscopy (SEM). The wear mechanisms of the ceramic drawing dies were investigated. Detailed observations and analyses of the die wear surface have revealed that the most common failure of the ceramic drawing die is the wear at its approach zone. FEM analysis showed that the compressive stresses on both sides of the corners at the approach zone are higher than those of other parts of the ceramic drawing die. Abrasive and adhesive wear were found to be the predominant wear mechanisms through the whole approach zone owing to the greater compressive stresses. Examination of the center bore surface at the die bearing zone of the ceramic drawing dies demonstrated that the wear occurred by light abrasive, no adhesion wear was observed

  18. Der Nahostkonflikt und die Medien

    Directory of Open Access Journals (Sweden)

    Carola Richter

    2014-06-01

    Full Text Available Diese Einführung in eine Themenausgabe zu den vielfältigen Rollen der Medien im Nahostkonflikt skizziert die Probleme, die sich für Medien und Journalisten als Akteure im Konflikt, Adressaten der Konfliktparteien und Anlass für Konflikt durch ihre Berichterstattung ergeben. Das Konfliktgebiet Israel und Palästina ist sowohl für Forschung über Auslandsbericht-erstattung, über transnationale Agenda Building- und Public Diplomacy-Prozesse als auch über mediensystemische Entwicklungen in Besatzer- und Besatzungsgebieten interessant. Der Artikel gibt einen Überblick über das Feld und führt dabei in die in der Themenausgabe präsentierten empirischen Studien zum Nahostkonflikt und den Medien ein.

  19. DIE VRYWILLIGERSMAGTE VAN GRIEKWALAND-WES

    African Journals Online (AJOL)

    teen gekant was, is dit op 15 Oktober 1880 by die Kaapkolonie ingelyf.9. Gedurende sy kortstondige bestaan van minder as 'n dekade lank het die kroonkolonie Griekwa- land-Wes met talle finansiele, ekonomiese, so- siale en ander probleme te doen gehad. Een van die ernstige probleme was die bedreiging wat.

  20. Die Gereformeerde Ekumeniese Sinode en Sending 1984

    African Journals Online (AJOL)

    opvatting. Indien 'n mens al die kerke wat aan die Gereformeerde. Ekumeniese Sinode (GES) behoort een vir een sendingmatig sal be- studeer, sal daar waarskynlik 'n sterk differensiasie tussen sommige kerke aan die lig kom. Die GES kan dus nie verantwoordelik gehou word vir individuele kerke se sendingopvatting nie.

  1. voorgeskiedenis tot die stigting van 'n unieverdedigingsmag

    African Journals Online (AJOL)

    gesien nie en toe die wetsontwerp op 23 Februa- rie 1912 deur Smuts in sy hoedanigheid as Mi- nister van Verdediging ingedien is, het Beyers heelwat kritiek daarop gehad. Beyers het be- weer dat dit op vergaderings geblyk het dat die volk wou he Engeland moet steeds die verdedi- ging waarneem aangesien die Unie ...

  2. Moderne diskoerse in die teologie vandag

    Directory of Open Access Journals (Sweden)

    J.H. van Wyk

    2013-05-01

    Full Text Available In hierdie artikel word aandag gevra vir enkele moderne diskoerse in die teologie vandag. Volgens die outeur staan die vrae oor God, Jesus, die mens en die aarde in die sentrum van belangstelling en oorheers dit in ’n groot mate die teologiese debat. Die opkoms van die moderne aggressiewe ateïsme, die wetenskaplike navorsing oor die historiese Jesus, die groeiende vrae oor die mens en die menslike samelewing, asook die dreigende ekologiese krisis op aarde, sorg vir nuwe debatte van ongekende omvang. Die outeur bespreek hierdie debatte oorsigtelik, met kritiek waar nodig, en sluit af met enkele rigtingwysers van wat hy as ‘goeie teologie’ verstaan. In this article attention is paid to some modern discourses in theology today. According to the author the questions about God, Jesus, man and the earth are in the centre of interest and to a large extent dominate the theological debate. The rise of modern aggressive atheism, the scientific research on the historic Jesus, the growing questions about man and human society as well as the threatening ecological crisis on earth, provide new discourses of unparalleled magnitude. The author provides a broad summary of these discourses, with criticism where necessary, and concludes with some indicators of his view what can be called ‘good theology’.

  3. DIE BEPERKING VAN MULTIOVULASIES IN KARAKOELOOIE NA ...

    African Journals Online (AJOL)

    Die geboorte van meer as 2 lammers per ooi is egter ongewens in die Karakoelbedryf aangesien dit aanleiding gee tot kleiner pelse veral wanneer voedingstoestande nie opti- maal is nie. In stoetteling is selfs tweelinge nie gewens nie, aangesien die ware fenotipiese waarde van die lammers nie in tweelinge te voorskyn ...

  4. Calvyn en die kerklike orde: Enkele opmerkings

    African Journals Online (AJOL)

    Om dié saak verder te belig word ook van die latere uitsprake van Calvyn in hierdie verband in berekening gebring. Met hierdie beperkte studie word dus in die eerste plek die feit in herinnering geroep dat dit vanjaar 450 jaar gelede is dat Calvyn se. Institusie die eerste maal in Basel verskyn het. Terselfdertyd word hier-.

  5. Leerteoretiese basis van die andragogie

    Directory of Open Access Journals (Sweden)

    C. J. A. Simpson

    1991-06-01

    Full Text Available Learning theory basis of andragogy. A cursory glance at andragogy creates the impression that humanistic learning theory plays an all encompassing role in the learner centered approach andragogy espouses. A closer look, however, reveals that Knowles (1973, after having made an intensive study of learning theory, created an extensive framework within which human resource development can take place. The fact that Knowles attracted critique from different areas, led to a need to ascertain the role different learning theories, if any, played in the emergence of andragogy. Having looked at the assumptions displayed by the andragogical approach, as well as a comparison of different learning theories and their connection with andragogy, it became clear that andragogy contains elements of various learning theories in an adapted way. These adaptations resulted in an approach to adult education in which learners are given the opportunity to be part of the learning process in such a way that they themselves contribute to the development which takes place. Opsomming Met 'n eerste oogopslag wil dit voorkom asof humanistiese leerteorie 'n oorheersende rol in die leerdergesentreerde benadering van andragogie speel. By nadere ondersoek blyk dit egter dat Knowles (1973, na 'n deeglike studie van verskillende leerteoretiese beginsels, 'n omvangryke raamwerk geskep het waarbinne, aan die hand van verskeie aangepaste leerteoretiese beginsels, menslike hulpbronontwikkeling kan plaasvind. As gevolg van die feit dat Knowles vanuit verskillende oorde kritiek op die lyf geloop het, is besluit om die rol wat verskillende leerteorieë in andragogie speel, te bestudeer. Dit blyk dat andragogie nie net elemente van verskillende leerteorieë bevat nie, maar dat toepaslike aspekte van die teoriee wat ondersoek is, benut en aangepas is om 'n geintegreerde benadering te bewerkstellig waarin veral volwassene-leerders by leergeleenthede en hulle selfontwikkeling betrek word.

  6. Die «ASEAN-Wirtschaftsgemeinschaft»

    DEFF Research Database (Denmark)

    Juego, Bonn

    2014-01-01

    Seit dem Ende der 1990er-Jahre verfolgt die ASEAN die Vision einer politischen, wirtschaftlichen und sozialen Gemeinschaft. Doch wie realistisch ist die Umsetzung eines solch ambitionierten Vorhabens vor dem Hintergrund der enormen Heterogenität der Region? ASEAN vereint Staaten auf...... Entwicklungsstufen, wie sie unterschiedlicher kaum sein können. Der Autor, Bonn Juego, nimmt die ASEAN Vision 2020 sowie die Debatten, die diesbezüglich in den einzelnen Ländern geführt werden, unter die Lupe. Er geht dem Potenzial des ASEANAnsatzes zu sozialer Teilhabe und wirtschaftlicher Verteilungsgerechtigkeit...

  7. Die pastorale begeleiding van predikante van die Nederduitse ...

    African Journals Online (AJOL)

    21 Jan 2013 ... Stone, M.F., 1999, Coaching, counselling & mentoring: How to choose & use the right technique to boost employee performance, AMACOM, New York. Strydom, W.A., 2011, 'Pastoraat aan getraumatiseerde kinders in die intensiewesorgeenheid: 'n Gestalt benadering', DD tesis, Universiteit van Suid-. Afrika ...

  8. 'n Begronde bedieningsmodel vir die diakonia van die gemeente

    African Journals Online (AJOL)

    15 Feb 2012 ... At first, various angles of approach to the research on ministry in ... Lingenfelter 2005; Armour & Browning 2000) en daarmee saam die ...... Grobler, A.B. & Van der Walt, A.L., 2008, 'An assessment of the management skills.

  9. Die ontwikkeling van menslike potensiaal in die Republiek van Suid ...

    African Journals Online (AJOL)

    Erna Kinsey

    Dit het dus ook te doen met lewenstandaard, aangesien lewenstandaard `n bepalende faktor is met betrekking tot die optimale ontwikkeling van menslike potensiaal. Ander minder materiële aspekte van menslike potensiaal het te doen met menslike vryheid, waaronder vryheid van spraak, beweging en keuse ter sake is.

  10. UIT DIE VOORGESKIEDENIS VAN DIE SUID-AFRIKAANSE VLOOT ...

    African Journals Online (AJOL)

    20 van 1898 van die Kaapkolonie, getiteld The Navy Contribution. Act, i898 is a.m. ... as a contribution towards the annual expenditure by the ...... The above are inclusive of all allowances for lodging and provisions. Petty Officer Ins ...... that system we can retain full constitutional control not only in theory but also complete ...

  11. Die Korallenfauna des Perm von Timor und die permische Vereisung

    NARCIS (Netherlands)

    Gerth, H.

    1926-01-01

    Bei den zahlreichen Rekonstruktionen der klimatologischen Verhältnisse, die man für das Ende des Palaeozoikums gemacht hat, ist man fast immer von der Kohlenbildung, der Florenverbreitung und den Vereisungserscheinungen ausgegangen. Der marinen Tierwelt hat man bei der Behandlung dieser Fragen meist

  12. Numerical investigation of the effect of friction conditions to increase die life

    Science.gov (United States)

    Mutlu, M. O.; Guleryuz, C. G.; Parlar, Z.

    2017-02-01

    The standard die materials in aluminium extrusion offer good mechanical properties like high tempering resistance, high strength and ductility. On the other hand, they struggle with the problem of sliding wear. As a result, there is a growing interest in using surface treatment techniques to increase the wear resistance of extrusion dies. In this study, it is aimed to observe the effects of the different friction conditions on material flow and contact pressure in extrusion process. These friction conditions can be obtained with the application of a variety of surface treatment. In this way, it is expected to decrease the friction force on the die bearing area and to increase the homogeneity of the material flow which will result in the increase of the quality of the extrudate as well as the improvement of the process economically by extending die life. For this purpose, an extrusion process is simulated with a finite element software. A die made of 1.2344 hot work tool steel-commonly used die material for aluminium extrusion process- has been modelled and Al 1100 alloy used as billet material. Various friction factor values defined on the die surface under the same process parameters and effects of changing frictional conditions on the die and the extrusion process have been discussed.

  13. [Dying with cancer: Hollywood lessons].

    Science.gov (United States)

    Niemeyer, Fernanda; Kruse, Maria Henriqueta Luce

    2013-12-01

    The study attempts to understand how dying from cancer is portrayed by five movies produced in Hollywood between 1993 and 2006. Based on the cultural studies and their post-structuralism version and supported by the notions of discourse and subjectivity, as proposed by philosopher Michel Foucault, we suggest one of the possible readings of the movie picture corpus. We assess how the movie picture discourse acts as a cultural pedagogy that produces ways of seeing dying with cancer: immortalizing the healthy body image, silencing death, taking care of the dead body and, finally, accepting death. Our proposal is intended to stimulate reflections that may contribute to care and education in nursing.

  14. Existential Needs among the Dying

    DEFF Research Database (Denmark)

    Moestrup, Lene

    meaning making. Methods: The key research question is: 1. What kind of existential needs are central to dying cancer patients and their relatives during the terminal phase in Danish hospices? Exploring this highly sensitive and complex research area entails substantial ethical responsibility during data...... based and practice relevant knowledge about the complexity of existential considerations and needs among dying cancer patients and their relatives in a secularized society as Denmark. Existential needs are seen as a multidimensional concept that encompasses religious, spiritual and secular existential...

  15. ’n Etiek van liefde: Die etiese perspektiewe van die Heidelbergse Kategismus

    Directory of Open Access Journals (Sweden)

    Koos Vorster

    2013-06-01

    Full Text Available Hierdie artikel behandel die etiese perspektiewe van die Heidelbergse Kategismus – een van die prominente belydenisskrifte in die gereformeerde tradisie. Die etiese relevansie is ingebed in die konfessie se verklaring van die tien gebooie. Die artikel verduidelik dat die etiek van die Heidelbergse Kategismus ten diepste ’n karakteretiek is en dat dit gelowiges oproep tot ’n etiek van liefde. Hierdie liefde sluit in liefde vir die verbondsgemeenskap, die bediening van die Woord, die heiligheid van God en die waardigheid van mense, die gemeenskap van die gelowiges, gesag, die lewe, die huwelik, privaatbesit en arbeid asook waarheid en geregtigheid. As gevolg van die sinekdogeekarakter van die wet is hierdie etiek van liefde vandag baie relevant. This article deals with the ethical relevance of one of the prominent confessions in the reformed tradition, namely the Heidelberg Cathechism. The ethical relevance lies in the confession’s elucidation of the ten commandments and its application to moral conduct. The article explains that the ethics of the Heidelberg Catechism is essentially a virtue ethics calling for an ethics of love. This love should include love for the covenantal communion, ministry of the Word, the holiness of God and the dignity of people, the communion of the saints, authority, life, marriage, private property and labour, and truth and justice. Due to the synecdochical character of the ten commandments this ethics of love is highy relevant in the present times.

  16. Improved design and durability of aluminum die casting horizontal shot sleeves

    Science.gov (United States)

    Birceanu, Sebastian

    The design and performance of shot sleeves is critical in meeting the engineering requirements of aluminum die cast parts. Improvement in shot sleeve materials have a major impact on dimensional stability, reproducibility and quality of the product. This investigation was undertaken in order to improve the life of aluminum die casting horizontal shot sleeves. Preliminary pin tests were run to evaluate the soldering, wash-out and thermal fatigue behavior of commercially available materials and coatings. An experimental rig was designed and constructed for shot sleeve configuration evaluation. Fabrication and testing of experimental shot sleeves was based upon preliminary results and manufacturing costs. Three shot sleeve designs and materials were compared to a reference nitrided H13 sleeve. Nitrided H13 is the preferred material for aluminum die casting shot sleeves because of wear resistance, strength and relative good soldering and wash-out resistance. The study was directed towards damage evaluation on the area under the pouring hole. This area is the most susceptible to damage because of high temperatures and impingement of molten aluminum. The results of this study showed that tungsten and molybdenum had the least amount of soldering and wash-out damage, and the best thermal fatigue resistance. Low solubility in molten aluminum and stability of intermetallic layers are main factors that determine the soldering and wash-out behavior. Thermal conductivity and thermal expansion coefficient directly influence thermal fatigue behavior. TiAlN nanolayered coating was chosen as the material with the best damage resistance among several commercial PVD coatings, because of relatively large thickness and simple deposition conditions. The results show that molybdenum thermal sprayed coating provided the best protection against damage under the pouring hole. Improved bonding is however required for life extension of the coating. TiAlN PVD coating applied on H13 nitrided

  17. Die Freunde im und die Freude am Fernsehen

    Directory of Open Access Journals (Sweden)

    Amina Ovcina Cajacob

    2012-09-01

    Full Text Available Das Ziel der vorliegenden Arbeit besteht darin, die Wirkungen von Popstars und Popbands auf Jugendliche (13- bis 17-Jährige zu erforschen. Im Mittelpunkt der Interessen steht die Frage, welche Wirkungen aus der Rezeption von Musiksendungen (bzw. Videoclips von Musiksendern entstehen und welche Charakteristika innerhalb der aufgebauten Beziehungen zu den Stars bemerkbar sind. Andererseits wurden die Unterschiede und Parallelen zwischen parasozialen Beziehungen zu den Stars und orthosozialen Beziehungen aufgezeigt. Im Zusammenhang mit der empirischen Untersuchung bezieht sich die Autorin auf den Uses-and-Gratifications-Approach, wobei die bedürfnissbefriedigenden Wirkungen von Musikkanälen und den dazu gehörigen Popstars im Mittelpunkt stehen. Mit Hilfe des Uses-and-Gratifications-Approach wird angenommen, dass das Konsumieren der Musiksendungen und der Musikstars von den Jugendlichen gezielt zur Befriedigung bestimmter Bedürfnisse eingesetzt wird.The objective of this study is to explore the effects of pop stars on adolescents (aged between 13 and 17. The focus of interest is the question what effect music channels (i.e. video clips from music channels produce and what characteristics are noticeable from the formed relationship between adolescents and pop stars. On the other side, parallels and differences have been drawn between the para-social relationships to pop stars and ortho-social relationships. In connection with empirical study, the author also refers to Uses-and Gratification-Approach where the need satisfying effects of music channels and pop stars are in focus. With the help of Uses-and Gratification-Approach it will be assumed, that aim of watching music channels and therefore pop stars will be pointed toward the gratification of specific needs.

  18. Metallic Reinforcement of Direct Squeeze Die Casting Aluminum Alloys for Improved Strength and Fracture Resistance

    Energy Technology Data Exchange (ETDEWEB)

    D. Schwam: J.F. Wallace: Y. Zhu: J.W. Ki

    2004-10-01

    The utilization of aluminum die casting as enclosures where internal equipment is rotating inside of the casting and could fracture requires a strong housing to restrain the fractured parts. A typical example would be a supercharger. In case of a failure, unless adequately contained, fractured parts could injure people operating the equipment. A number of potential reinforcement materials were investigated. The initial work was conducted in sand molds to create experimental conditions that promote prolonged contact of the reinforcing material with molten aluminum. Bonding of Aluminum bronze, Cast iron, and Ni-resist inserts with various electroplated coatings and surface treatments were analyzed. Also toughening of A354 aluminum cast alloy by steel and stainless steel wire mesh with various conditions was analyzed. A practical approach to reinforcement of die cast aluminum components is to use a reinforcing steel preform. Such performs can be fabricated from steel wire mesh or perforated metal sheet by stamping or deep drawing. A hemispherical, dome shaped casting was selected in this investigation. A deep drawing die was used to fabricate the reinforcing performs. The tendency of aluminum cast enclosures to fracture could be significantly reduced by installing a wire mesh of austenitic stainless steel or a punched austenitic stainless steel sheet within the casting. The use of reinforcements made of austenitic stainless steel wire mesh or punched austenitic stainless steel sheet provided marked improvement in reducing the fragmentation of the casting. The best strengthening was obtained with austenitic stainless steel wire and with a punched stainless steel sheet without annealing this material. Somewhat lower results were obtained with the annealed punched stainless steel sheet. When the annealed 1020 steel wire mesh was used, the results were only slightly improved because of the lower mechanical properties of this unalloyed steel. The lowest results were

  19. Die WTO in Hongkong: Zwischenergebnisse einer "Entwicklungsrunde"

    OpenAIRE

    Küblböck, Karin; Six, Clemens

    2006-01-01

    Die sechste Ministerkonferenz der Welthandelsorganisation (WTO), die von 13. bis 18. Dezember 2005 in Hongkong stattfand, war mit dem Anspruch angetreten, die Agenda der Doha-Entwicklungsrunde, also die B erücksichtigung der Interessen und ökonomischen Bedürfnisse der Entwicklungsländer und insbesondere der am wenigsten entwickelten Staaten, um wesentliche Schritte im Hinblick auf einen erfolgreichen Abschluss voranzubringen. Die Ergebnisse sind vor dem Hintergrund des Anspruches dieser Verha...

  20. Chirurgie in die Grieks-Romeinse era

    Directory of Open Access Journals (Sweden)

    François P. Retief

    2006-09-01

    Full Text Available In die Grieks-Romeinse era het mediese behandeling kenmerkend uit drie elemente bestaan, naamlik regimen (dieet en gesonde leefwyse, geneesmiddels en chirurgie – laasgenoemde alleen toegepas indien regimen en geneesmiddels onsuksesvol was. Bewyse van primitiewe chirurgie dateer terug na die Bronstydperk, en in Homerus se eposse is heelwat vermelding van die chirurgiese hantering van oorlogswonde, met tussenkoms van die gode. Met die koms van empiriese geneeskunde in die 5de eeu v.C. het chirurgie in die Hippokratiese Corpus prominent gefigureer met beduidende bydraes in veral die ortopediese veld en hoofbeserings. Uitbouing van anatomiese en fisiologiese kennis, gebaseer op disseksie van menslike kadawers in Alexandrië vanaf die laat 4de eeu v.C., het chirurgie ’n hupstoot gegee. Teen die Romeinse era vanaf die 2de eeu v.C. het snykundetegnieke (en -instrumente beduidend verbeter, maar is steeds oorwegend deur Griekse geneeshere beoefen. Van geneeshere is steeds verwag om al drie bovermelde terapeutiese modaliteite te bemeester, maar chirurgie het meer aansien verwerf en daar is al meer in onderafdelings van chirurgie soos oogheelkunde, vrouesiektes en verloskunde, blaaskwale en mond- en keelsnykunde gespesialiseer. Militêre geneeskunde was in die Romeinse Ryk ’n belangrike aktiwiteit, en het veral traumachirurgie uitgebou. Betreding van die buik- en toraksholtes was nie meer noodwendig fataal nie, en veeartsenykunde het tot stand gekom. Die eerste beduidende chirurgiehandboek ná die Hippokratiese Corpus is in die 1ste eeu n.C. deur Celsus opgestel. Vanaf die 3de eeu het die chirurgieberoep min vordering gemaak, die beroepstaal het mettertyd van Grieks na Latyn verander en kundigheid is later veral deur Islam-geneeshere na die Middeleeue en later oorgedra.

  1. Bevordering van transformerende leer: Die skryf van ’n reflektiewe joernaal in die Natuurwetenskappe

    Directory of Open Access Journals (Sweden)

    Erna R. du Toit

    2012-03-01

    Full Text Available Die doel van die artikel is om aan te toon hoe die skryf van ’n reflektiewe joernaal in die Natuurwetenskappe die perspektiewe en denke van onderwysstudente kan transformeer en/of leer kan bevorder. Die studie maak voorspraak vir die gebruik van ’n reflektiewe joernaal as ’n instrument vir studente om betekenis te gee aan die leeromgewing vanuit verskillende perspektiewe deur te leer in praktyk. ’n Kwalitatiewe navorsingsmetode is gevolg om die inskrywings in ’n joernaal te analiseer aan die hand van bepaalde indikatore. Die bevindinge toon dat die meeste studente na die praktykervaring positief was en sommiges het tot ander perspektiewe vanweë hul ervaring gekom.

  2. Die invloed van drie kruisbestuiwers op die saadinhoud van Minneola tangelo (Citrus parodist x C reticulata

    Directory of Open Access Journals (Sweden)

    H. J. Esterhuizen

    1991-07-01

    Full Text Available Die invloed van verskillende kruisbestuiwers (Clementine, Empress en Valencia op die gemiddelde saadinhoud van Minneo­la tangelo is ondersoek. Clementine en Empress as kruisbestuiwers het die grootste invloed op die gemiddelde saadinhoud van die vrugte gehad, terwyl dié van Valencia nie noemenswaardig was nie. Die gemiddelde saadinhoud van die vrugte het afgeneem met toename in afstand vanaf die kruisbestuiwer. Indien ’n beperking op die afstand tussen kultivar en kruisbestuiwer geplaas word, sal ’n groter persentasie vrugte aan uitvoerstandaarde ten opsigte van saadinhoud voldoen.

  3. DIE ROL VAN DIE SUID-AFRIKAANSE WEERMAG IN NATUUR- EN ...

    African Journals Online (AJOL)

    sedert die vroeg 1900's deur die Weermag be- heer. In 1967 was dit die eerste militere terrein wat tot privaatnatuurreservaat verklaar is. Vhembe bestaan uit 4 hoofplantgemeenskappe nl. rivieraewerbos, vloedvlaktes, ranteveld en die sandveldplato. Wildsoorte op die terrein sl!Jit rooibokke, bosbokke, waterbokke, koedoes,.

  4. Die era van Suid-Afrika se militere hoogbloei met die ...

    African Journals Online (AJOL)

    4 Jun 1976 ... Die Toyota 1200 bakkie is geadverteer met die woorde 'Hier kom die pantserbakkie', teen die agtergrond van 'n olifant tenk.32. Daar is ook 'n betrekking deur Thorold en van Wyk geadverteer waar militere opleiding 'n voorvereiste was.33. Daar was ook films wat weermag en polisie gebasseer is wat in die ...

  5. Riglyne vir ‘n omvattende verrykingsprogram vir die bevordering van die geestesgesondheid

    Directory of Open Access Journals (Sweden)

    Antoinette Gmeiner

    1997-12-01

    Full Text Available In Suid-Afrika, met die snelle veranderinge in die politiek, ekonomie, lewenstyl en tegnologiese vooruitgang, gepaard met die geweld tans in die land, is die lewenskwaliteit van mense so bemvloed dat produktiwiteit en gedrag benadeel is. *Please note: This is a reduced version of the abstract. Please refer to PDF for full text.

  6. Etíese perspektiewe vir die bantering van konflik in die mediese ...

    African Journals Online (AJOL)

    mits versagtende omstandighede nie aangevoer kan word nie. Die howe oefen dan ook alleen sy regterlike funksie uit oor 'n konkrete geskil wat van daadwerklike belang vir die werklike partye is (Strauss 1982:14). Die hof laat hom lei deur die maatstaf van goeie sedes, die boni mores. Regter Mostert se verduideliking in ...

  7. ontwikkeling van die gemenereg in die lig van artikels 39(2)

    African Journals Online (AJOL)

    Administrator

    'n Mens kan met reg vra of die ius connubiorum van Brouwer en die Law of. Husband and Wife van ... AD 560 (Geheime Raad) 563. 5 Sien vir besonderhede Hahlo en Kahn SA Legal System and its Background 304. ..... Die Franse chemikus, Antoine Lavoisier, is in 1794 tydens die Franse revolusie tereggestel. Terwyl die ...

  8. Die wonders in Johannes 6 verklaar aan die hand van 'n ...

    African Journals Online (AJOL)

    Maar die Evangelie van Johannes gee self 'n aanduiding van wat die intensie van die geskrif is, te wete Johannes 20: 30-31: Jesus het nog baie ander wondertekens, wat nie in hierdie boek beskrywe is nie, voor sy dissipels gedoen. Maar hierdie wonder tekens is beskrywe sodat julle kan glo dat Jesus die Christus is, die.

  9. Mechanical characteristics of a tool steel layer deposited by using direct energy deposition

    Science.gov (United States)

    Baek, Gyeong Yun; Shin, Gwang Yong; Lee, Eun Mi; Shim, Do Sik; Lee, Ki Yong; Yoon, Hi-Seak; Kim, Myoung Ho

    2017-07-01

    This study focuses on the mechanical characteristics of layered tool steel deposited using direct energy deposition (DED) technology. In the DED technique, a laser beam bonds injected metal powder and a thin layer of substrate via melting. In this study, AISI D2 substrate was hardfaced with AISI H13 and M2 metal powders for mechanical testing. The mechanical and metallurgical characteristics of each specimen were investigated via microstructure observation and hardness, wear, and impact tests. The obtained characteristics were compared with those of heat-treated tool steel. The microstructures of the H13- and M2-deposited specimens show fine cellular-dendrite solidification structures due to melting and subsequent rapid cooling. Moreover, the cellular grains of the deposited M2 layer were smaller than those of the H13 structure. The hardness and wear resistance were most improved in the M2-deposited specimen, yet the H13-deposited specimen had higher fracture toughness than the M2-deposited specimen and heat-treated D2.

  10. How Tycho Brahe really died

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland; Petersen, Lars

    2001-01-01

    In 2001 we commemorate the 4th centenary of the death of Tycho Brahe, perhaps the first great scientists in a modern sense.This famous Danish astronomer died in Prague on the 24th of October 1601, eleven days after he had attended a banquet at the Bohemian count of Rosenberg. Tycho was too courte...

  11. Die Suche nach den Gottesteilchen

    CERN Multimedia

    2007-01-01

    2008 wird der größte jemals gebaute Teilchenbeschleuniger in Betrieb genommen Anlässlich des Mathematik-Jahres 2008 hat der Experimentalphysiker der Universität Hamburg und der designierte Generaldirektor des europäischen Zentrums für Teilchenphysik CERN in Genf, Rolf-Dieter Heuer, die Bedeutung des Dialogs zwischen Naturwissenschaftlern und Philosophen hervorgehoben.

  12. When a major star dies

    International Nuclear Information System (INIS)

    Joubert, G.

    1988-01-01

    Astrologers are slowly learning what happens when a star dies. On the night of 23-24 February 1987, the light of an exploding star - a supernova with the name SN 1987A - reached the earth. In this article this astrological event of the century are discussed, and its importance for astrologers

  13. polisemie in die woordeboek - 'n

    African Journals Online (AJOL)

    mous items, the problem of monosemic prototype categories vs. polysemous prototype categories, ...... bv. te make met kulturele norme vir die drink van warm vloeistowwe. ..... (en nie bv. teen ander soorte water of ander soorte chemiese middele nie) gede- ...... INLIGTING VERSKAF TE WORD (EN VERW AG DIT AS SODA-.

  14. Die verhouding tussen kerk en staat: Enkele modelle met verwysing ...

    African Journals Online (AJOL)

    ook ingaan op die vraag na die reg tot opstand teen die gesag van die staat soos dit in hierdie modelle beantwoord word. Ons wil eindig by die vraag na 'n teologiese model wat geskik is vir ons dag. 1. DIE TEOLOGIESE MODEL VAN DIE ROOMS-KATOLIEKE. KERK. Die Rooms-Katolieke Kerk se opvatting word bepaal ...

  15. die rol van kleurlinge in suid afrika se militere verlede

    African Journals Online (AJOL)

    die geval, want hierdie volks- groep het 'n lang en kleurryke historiese verbin- tenis met die miltere verlede van Suid-Afrika. Die feit dat die Kleurlinge nou op die drumpel staan van 'n nuwe tydvak in die staatkundige ontwikke- ling van die Republiek van Suid-Afrika, beteken ook nie dat hulle vir die eerste maal ten nouste.

  16. Die stand van wiskundeonderwys in Afrikaanse skole

    Directory of Open Access Journals (Sweden)

    Gerrit Stols

    2012-03-01

    Full Text Available Hoërordedenkvaardighede is noodsaaklike basiese vaardighede vir die een-en-twintigste eeu aangesien rekenaars berekeninge en algoritmes baie vinniger en akkurater kan doen as mense. Dit beteken dat skole leerders moet toerus om logies te dink, patrone te ontdek, bewyse te lewer, asook om nieroetineprobleme op te los. Hierdie fasette wat as hoërordedenke geklassifiseer word, is die kern van wiskundige denke en ontwikkeling. Suid-Afrika neem aan verskeie internasionaal vergelykende studies deel. Met behulp van hierdie vergelykende studies kan bepaal word hoe die Afrikaanse wiskundeleerders in Suid-Afrika se prestasie met dié van leerders in ander lande vergelyk en ook wat die tekortkominge in die wiskundeonderwys is. Volgens die 2003-TIMSS-uitslae is die probleem in Afrikaanse skole juis dié vrae wat hoërordedenke vereis. Dit beteken dat die Afrikaanse skole ’n doelbewuste poging sal moet aanwend om hoërordedenke te ontwikkel. Die 1999-TIMSS-videostudie toon dat die lande wat die beste presteer, soos Japan, tydens onderrig meer tyd wy aan die ontwikkeling van begripsvorming en aan die oplos van moeiliker probleme. Die fokus in die presterende lande is op die ontwikkeling van hoërordedenke deur probleemoplossing. Daar word dus minder tyd afgestaan aan herhaling van roetine- of soortgelyke oefeninge wat ’n rekenaar ook kan doen. Die omgekeerde hiervan is ’n tipiese verskynsel in Afrikaanse skole, waar ’n onderwyser byvoorbeeld een of meer voorbeelde op die bord doen waarna die leerders ’n hele aantal soortgelyke roetine-oefeninge doen.

  17. Tribological properties of ion-implanted steels

    International Nuclear Information System (INIS)

    Iwaki, Masaya

    1987-01-01

    The tribological properties such as surface hardness, friction and wear have been studied for low carbon steels and tool steels implanted with many types of ion including metallic elements. The hardness measured by Vickers or Knoop hardness testers as a function of normal load is dependent on the implanted species, fluence and substrate. The friction coefficients measured by Bowden-Leben type of friction tests or detected during wear tests also depend on the implantation conditions. The improvement in the wear resistance, which is most important for industrial use of implanted materials, has been investigated for AISI H13 prehardened and tool steels implanted with nitrogen and boron ions. The relationship between hardness, friction and wear is discussed in comparison with the microcharacteristics such as composition and chemical bonding states measured by means of secondary ion mass spectrometry and X-ray photoelectron spectroscopy. It is concluded that the increase in hardness and/or the decrease in friction coefficient play(s) an important role in improving the wear resistance, and the relationship between relative wear volume and relative hardness is correlated for boron and nitrogen implantation. (orig.)

  18. 2D 1H -13C Heteronuclear Shift Correlation Of 2a - Hydroxy Aiantolactone From Pulicaria Undulata C.A. Mey

    Directory of Open Access Journals (Sweden)

    A. Rustaiyan

    1992-07-01

    Full Text Available We have reported recently the isolation and characterization of several sesquiterpene lactones from Pulicaria undulata (1."nThe lactones were isolated from an Et20 - Petrol (1:3 fraction by different chromatographic techniques including HPLC (RP 8, MeOH - H2O, 13:7."nIn this way three eudesmanolides 1 - 3, a guaianolide 4, a nor -guaianolide 5, as well as the pseudoguaianolide 6 and the xanthanolide 7 were isolated. One of the eudesmanolides (2a - hydroxy aiantolactone, 1, was present as the main component."nSuch lactones being known as biologically active substances, we have decided to describe for the first time a detailed interpretation of proton, 1H -NMR, 13C - NMR and 2D lH -13C - heteronuclear shift correlation spectra of 2a - hydroxy aiantolactone. The stereochemistry of C - 2 , C - 7 and C - 8 was determined by the NOESY experiments, H - 7 and H - 8 are in the a configuration and H - 2 is in the b configuration.

  19. Structural investigation of 18-crown-6 complexes of Tri organotin carboxylate by 1H, 13C, 19F and 119Sn nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Foladi, S.; Yousefi, M.; Mohammadpour Ammini, M. M.

    2002-01-01

    Single crystal structure determination of several 18-crown 6 complexes of orga nation derivatives reveals formation of aqua complex through hydrogen bonding to 18-crown-6, which is an important feature in their structure. In the majority of those studies, mono- and dichloro organotin have been used for complexation of them with crown ethers. In the present work, several 18-crown 6 complexes of tri organotin acetate[(C 6 H 5 ) 3 SnOCOCX 3 ] 2 , 18 C6 ], X=F, Cl, and H, have been prepared. The Lewis acidity of tin moiety in tri organotin carboxylate have been tailored by replacing hydrogen atoms of acetate group with chlorine and fluorine and influence of them in the formation of aqua complex with 18 C6 have been studied by infrared. 1 H, 13 C, 19 F and 119 Sn nuclear magnetic resonance spectroscopes. The effects of coordinating and non-coordinating solvent in status of structure in solution have been explored

  20. Genomic analysis of a 1 Mb region near the telomere of Hessian fly chromosome X2 and avirulence gene vH13

    Directory of Open Access Journals (Sweden)

    Chen Ming-Shun

    2006-01-01

    Full Text Available Abstract Background To have an insight into the Mayetiola destructor (Hessian fly genome, we performed an in silico comparative genomic analysis utilizing genetic mapping, genomic sequence and EST sequence data along with data available from public databases. Results Chromosome walking and FISH were utilized to identify a contig of 50 BAC clones near the telomere of the short arm of Hessian fly chromosome X2 and near the avirulence gene vH13. These clones enabled us to correlate physical and genetic distance in this region of the Hessian fly genome. Sequence data from these BAC ends encompassing a 760 kb region, and a fully sequenced and assembled 42.6 kb BAC clone, was utilized to perform a comparative genomic study. In silico gene prediction combined with BLAST analyses was used to determine putative orthology to the sequenced dipteran genomes of the fruit fly, Drosophila melanogaster, and the malaria mosquito, Anopheles gambiae, and to infer evolutionary relationships. Conclusion This initial effort enables us to advance our understanding of the structure, composition and evolution of the genome of this important agricultural pest and is an invaluable tool for a whole genome sequencing effort.

  1. Die naslaanpotensiaal van lemmakandidate vir ʼn ...

    African Journals Online (AJOL)

    Kate H

    Afrikaans-woordeboek in die gedrukte medium plaas welbekende tradisionele beperkinge op die leksikograaf, waarvan die vernaamste dié op ruimte is. Gegee die konteks, teikengebruiker, gebruikersituasie en funksie van die woordeboek moet ...

  2. Influence of the supporting die structures on the fracture strength of all-ceramic materials.

    Science.gov (United States)

    Yucel, Munir Tolga; Yondem, Isa; Aykent, Filiz; Eraslan, Oğuz

    2012-08-01

    This study investigated the influence of the elastic modulus of supporting dies on the fracture strengths of all-ceramic materials used in dental crowns. Four different types of supporting die materials (dentin, epoxy resin, brass, and stainless steel) (24 per group) were prepared using a milling machine to simulate a mandibular molar all-ceramic core preparation. A total number of 96 zirconia cores were fabricated using a CAD/CAM system. The specimens were divided into two groups. In the first group, cores were cemented to substructures using a dual-cure resin cement. In the second group, cores were not cemented to the supporting dies. The specimens were loaded using a universal testing machine at a crosshead speed of 0.5 mm/min until fracture occurred. Data were statistically analyzed using two-way analysis of variance and Tukey HSD tests (α = 0.05). The geometric models of cores and supporting die materials were developed using finite element method to obtain the stress distribution of the forces. Cemented groups showed statistically higher fracture strength values than non-cemented groups. While ceramic cores on stainless steel dies showed the highest fracture strength values, ceramic cores on dentin dies showed the lowest fracture strength values among the groups. The elastic modulus of the supporting die structure is a significant factor in determining the fracture resistance of all-ceramic crowns. Using supporting die structures that have a low elastic modulus may be suitable for fracture strength tests, in order to accurately reflect clinical conditions.

  3. a studyof faecal of faecal coliform die coliform die coliform die-off

    African Journals Online (AJOL)

    eobe

    COLIFORM DIE-OFF IN SEWAGE SLUDGE DRYING BED. OFF IN SEWAGE SLUDGE ..... This method was used to measure evaporation from the bed because of .... thermometer with external sensor probe, model No. ST-9283A/B/C and a ...

  4. Die spel van assosiasies in en om 'Die verlossing van die beeld' van Breyten Breytenbach

    Directory of Open Access Journals (Sweden)

    P.A. du Toit

    2005-07-01

    Full Text Available The play of association in and around 'The liberation of the image' by Breyten Breytenbach This analysis focuses on the conjunction of memory and imagination, which is an important impulse in, and key to, Breytenbach’s work. The play with language and with associations, the foregrounding, in the short story, “Die verlossing van die beeld” (Breytenbach, 1983 with its metafictional title and apparently divergent motifs (rain/water, watch, onion, the death and burial of a grandfather acts, as it were, as an invitation to the reader to become a co-player. The reader ventures on a search for traces, intertextual links within the Breytenbach oeuvre and for already acknowledged influences such as Surrealism (which in turn casts some light on the strange title of the story and the Eastern philosophies such as Zen and the even older Taoism. The analysis also takes into account the context in which “Mouroir” was written, namely Breytenbach’s term in prison (1975-1982. Seeing that the writer had to hand in his manuscripts to the jail authorities regularly, he might have decided, consciously or by intuition, to hide some thoughts and feelings behind a screen or a mask, in, for example in “Die verlossing van die beeld”, a lighter tone and irony.

  5. Die Romeinse nastrewing van onsterflikheid deur middel van memoria

    Directory of Open Access Journals (Sweden)

    D. R. Fouché

    1985-05-01

    Full Text Available Benewens die omvangryke en nasionale manifestasies van die oorspronklike onsterflikheidsgedagte in die Romeinse gemeenskap, vind ons by die Romein op kleiner skaal in groepe of indiwidueel ’n strewe na onsterflikheid langs die weg van memoria. Soos aangetoon sal word, verskil die pogings van die verskillende groepe radikaal van mekaar, hoewel die strewe en einddoel dieselfde bly, naamlik om deur die daarstelling van memoria op die gebied van woord of daad onsterflikheid te bekom.

  6. Corrosion resistant steel

    International Nuclear Information System (INIS)

    Zubchenko, A.S.; Borisov, V.P.; Latyshev, V.B.

    1980-01-01

    Corrosion resistant steel for production of sheets and tubes containing C, Mn, Cr, Si, Fe is suggested. It is alloyed with vanadium and cerium for improving tensile properties and ductility. The steel can be melted by a conventional method in electric-arc or induction furnaces. The mentioned steel is intended to be used as a substitute for nickel-bearing austenitic steels

  7. Professionalisme met verwysing na die posisie van bedryfsielkunde en die bedryfsielkundige in Suid-Afrika

    Directory of Open Access Journals (Sweden)

    A. van der Merwe

    1981-11-01

    Bedryfsielkunde, as relatief jong maar snelgroeiende wetenskap, word aan die hand van ses kriteria vir 'n professie evalueer. Resultate in hierdie verband dui in die algemeen daarop dat die vakgebied alreeds vir 'n aantal jare in 'n oorgangsfase tot ‘n volwaardige professie is en dat daar in hierdie proses reeds ver op die professionele kontinuum gevorder is. Verdere onder-soeke ten opsigte van professionele opleiding, die statutêre organisering van Bedryfsielkunde asook 'n professionele kode en vereniging vir die Bedryfsielkunde word bepleit ten einde die professionele posisie van die vakgebied volledig te konsolideer.

  8. Plasma nitriding of steels

    CERN Document Server

    Aghajani, Hossein

    2017-01-01

    This book focuses on the effect of plasma nitriding on the properties of steels. Parameters of different grades of steels are considered, such as structural and constructional steels, stainless steels and tools steels. The reader will find within the text an introduction to nitriding treatment, the basis of plasma and its roll in nitriding. The authors also address the advantages and disadvantages of plasma nitriding in comparison with other nitriding methods. .

  9. Process Optimization of EDM Cutting Process on Tool Steel using Zinc Coated Electrode

    Directory of Open Access Journals (Sweden)

    Hanizam H.

    2017-01-01

    Full Text Available In WEDM machining process, surface finish quality depends on intensity and duration of spark plasma. Electrode wire diameter has significant effect on the spark intensity and yet the studies on this matter still less. Therefore, the main objectives of this studies are to compare the different diameters of zinc coated and uncoated brass electrode on H13 tool steel surface roughness. The experiments were conducted on Sodick VZ300L WEDM and work piece material of tool steel AISI H13 block. Electrode of zinc coated brass with diameters of 0.1 mm, 0.2 mm, 0.25 mm and uncoated brass 0.2 mm were used. The surface roughness of cutting was measured using the SUR-FTEST SJ-410 Mitutoyo, surface roughness tester. The results suggest that better surface roughness quality can be achieved through smaller electrode wire diameter. The zinc coated improves flushing ability and sparks intensity resulting in better surface finish of H13 tool steel. New alloys and coating materials shall be experimented to optimized the process further.

  10. Killing, letting die and euthanasia.

    Science.gov (United States)

    Husak, D N

    1979-12-01

    Medical ethicists debate whether or not the moral assessment of cases of euthanasia should depend on whether the patient is 'killed' or 'allowed to die'. The usual presupposition is that a clear distinction between killing and letting die can be drawn so that this substantive question is not begged. I contend that the categorisation of cases of instances of killing rather than as instances of letting die depends in part on a prior moral assessment of the case. Hence is it trivially rather than substantively true that the distinction has moral significance. But even if a morally neutral (ie non-question begging) distinction could be drawn, its application to the euthanasia controversy is problematic. I illustrate the difficulties of employing this distinction to reach moral conclusions by critically discussing Philippa Foot's recent treatment of euthanasia. I conclude that even if an act of euthanasia is an instance of killing, and there exists a prima facie moral duty not to kill, and no more stringent duty overrides this duty, one still cannot determine such an act to be morally impermissible.

  11. Killing, letting die and euthanasia.

    Science.gov (United States)

    Husak, D N

    1979-01-01

    Medical ethicists debate whether or not the moral assessment of cases of euthanasia should depend on whether the patient is 'killed' or 'allowed to die'. The usual presupposition is that a clear distinction between killing and letting die can be drawn so that this substantive question is not begged. I contend that the categorisation of cases of instances of killing rather than as instances of letting die depends in part on a prior moral assessment of the case. Hence is it trivially rather than substantively true that the distinction has moral significance. But even if a morally neutral (ie non-question begging) distinction could be drawn, its application to the euthanasia controversy is problematic. I illustrate the difficulties of employing this distinction to reach moral conclusions by critically discussing Philippa Foot's recent treatment of euthanasia. I conclude that even if an act of euthanasia is an instance of killing, and there exists a prima facie moral duty not to kill, and no more stringent duty overrides this duty, one still cannot determine such an act to be morally impermissible. PMID:541821

  12. Die ausbildung von wertbedeutungen im schuljugendalter*

    Directory of Open Access Journals (Sweden)

    Siegfried Heusinger

    1978-12-01

    Full Text Available Die folgenden Darlegungen stützen sich auf Untersuchungsergebnisse des Verlassers zur Sprachentwicklung in der Ontogenese. Angeregt wurde die UnterSuchung durch die besonders in den letzten Jahren in mehreren Ländern verstärkt erhobenen Forderungen, nicht nur die Sprache des Klein­ kindes, sondern vornehmlich den Entwicklungsstand der Schülersprache auf den einzelnen Klassenstufen zu erforschen und den Prozeß der Sprachentwicklung des Schülers genauer zu bestimmen. Die Forderungen sind (so z. B. in der DDR durch das Bestreben motiviert, weitere wissenschaftliche Voraussetzungen für die Verbesserung der muttersprachlichen Bildung und Erzliehung zu schaffen. Es geht also vor allem um Bedürfnisse des Muttersprachunterrichts, die aus der gesellschaftlichen Bedeutung der Sprache überhaupt und den steigenden Anforderungen an die gesellschaftliche Kommunikation insbesondere erwachsen.

  13. NORMERING IN DIE AFRIKAANSE RADIO- EN TELEVISIEDIENS ...

    African Journals Online (AJOL)

    soortnaam plus soortnaam" kan albei komponente in Engels. 'n hoofletter kry, in Afrikaans slegs die eerste lid. Vergelyk Cash. Sale,. Kontantultverkoping. Uit 'n reklame-oogpunt Is die Engelse model bulgsamer, funksioneler en doelmatiger as ...

  14. [Die Gründung...] / Anders Henriksson

    Index Scriptorium Estoniae

    Henriksson, Anders

    2004-01-01

    Rets.: Karsten Brüggemann. Die Gründung der Republik Estland und das Ende des "Einen und unteilbaren Russland" : die Petrograder Front des Russischen Bürgerkrieges, 1918-1920. Wiesbaden : Harrassowitz, 2002

  15. Properties of powder metallurgy steel forgings

    International Nuclear Information System (INIS)

    Crowson, A.; Anderson, F.E.

    1977-01-01

    The effects of processing variables on the mechanical properties of heat-treated powder metallurgy (P/M) steel forgings were determined. Prealloyed 4600 steel powder blended with graphite to yield 4640 was compacted into preforms and hot forged in a warm, closed die. Variables studied were preform density, method of lubrication, preform sintering (time, temperature and atmosphere), forging pressure (20 and 40 tsi) and temperature (1850 0 F, 2000 0 F and 2200 0 F), and forging ratio (0.75 and 0.95). Relationships between interconnected porosity and total porosity for the various preform densities were determined. High density compacts required higher sintering temperatures due to the restricted mobility of the reducing gases in the pores. Die wall lubrication was comparable to admixed lubrication, and it simplified powder mixing and preform sintering operations. Forgings with densities from 99 to 99.8 percent of theoretical density were attained with a forging pressure of 20 to 40 tsi and preform temperatures of 2000 0 F and above. At forging conditions which resulted in forgings with acceptable mechanical properties, complete die fill was accomplished at a forging ratio of 0.95, whereas incomplete die fill resulted at a forging ratio of 0.75. The response of P/M forgings to heat treatment was comparable to that for wrought materials, and the resultant tensile and yield strengths were equivalent to the strength values described for wrought 4640 steel in AMS specification 6317B. In addition, ductility and impact properties of P/M forgings with near theoretical density (99.5+ percent) were comparable to bar stock forgings

  16. Die uitbeelding van die vrou in Huisgenoot (1963 en 2013: ’n Multimodale diskoersanalise

    Directory of Open Access Journals (Sweden)

    Susann H. Marais

    2017-05-01

    Full Text Available Die standpunt dat die mens en die media in ’n verhouding van wedersydse beïnvloeding staan, sowel as die studie wat die kulturele konseptualisering van vroulikheid in twee Huisgenoot-uitgawes (1953 en 2003 ondersoek, geld as uitgangspunt vir dié studie. Hierdie studie het ten doel om te bepaal of daar ’n verskil is in die uitbeelding van die vrou in die Huisgenoot uitgawes van onderskeidelik 1963 en 2013. Volgens navorsing werk die visuele beeld en geskrewe teks saam om ’n boodskap oor te dra. Multimodale diskoersanalise (MDA word juis gebruik om beide visuele beeld en geskrewe teks te bestudeer. Sodoende word die metode van intersemiotiese komplementariteit binne MDA in hierdie studie gebruik. Die studie kom tot die gevolgtrekking dat die uitbeelding van die ideale vrou se verantwoordelikhede uitgebrei is, maar dat die vrou se rol tóg tot sekere ruimtes beperk word, soos die sigbaarheid van die moeder-stereotipe weerspieël.

  17. Die waarde van voorafopleiding deur die ouer vir pedo-oudiometrie by drie- en vierjarige kleuters

    Directory of Open Access Journals (Sweden)

    Merisa Lodewyckx

    1981-11-01

    Full Text Available Die verkryging van akkurate, betroubare inligting aangaande die gehoorvermoë van jong kinders is van besondere belang vir die oudioloog, maar word dikwels bemoeilik aangesien die kleuter nie goeie samewerking bied in die vreemde pedo-oudiometriese situasie nie. Die oplossing hiervoor is grootliks geleë in die opleiding van die kind voor formele  gehoortoetsing en meer spesifiek  opleiding tuis deur die ouer. Die doel van hierdie studie was om 'n voorbereidende program op te stel wat die ouer tuis met die kind kan uitvoer, voordat formele  toetsing plaasvind. Die waarde en effek van hierdie program in die pedo-oudiometriese situasie is geevalueer by 'n groep drie- en vierjarige kleuters. Resultate dui daarop dat laer en meer akkurate drempels, 'n korter toetstydperk, verminderde angs en beter samewerking verkry is by die kleuters wat vooraf  opleiding ontvang het. Die opleidingsprogram kan dus in die kliniese praktyk benut word as voorafopleiding  vir pedo-oudiometrie.

  18. Die woordeboek vir meganiese ingenieurs: Vorderingsverslag

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1990-07-01

    Full Text Available Die komitee van die Nasionale Vakterminologiediens (NVD wat ’n woordeboek vir meganiese ingenieurswese saamstel en in Januarie 1986 met sy werksaamhede begin het, maak goeie vordering. Die dag-tot-dag-werk word deur 'n redaksiekomitee behartig wat twee keer maandeliks vergader en uit verteenwoordigers van universiteite, SAVD, YSKOR, SABS en ander instansies bestaan.

  19. Die Reformdiskussion in der senegalesischen Sprachplanungs- politik

    African Journals Online (AJOL)

    Die Reformdiskussion in der senegalesischen Sprachplanungspolitik 13 hatten afrikanische Bildungspolitiker und Kulturtheoretiker (Senghor, Nkrumah, Kenyatta, etc.) sehr früh die Rolle der Sprache und Bildung in einem zukünftigen souveränen afrikanischen Staat anerkannt. Die damals geführten staatsrechtlichen ...

  20. Taalgesindhede en die onderrig van Afrikaans

    Directory of Open Access Journals (Sweden)

    Barbara Bosch

    2013-02-01

    Full Text Available In die onderrig aan en aanleer van Afrikaans deur nie-moedertaalsprekers behoort daar in 'n multi-kulturele omgewing met taalgesindhede rekening gehou te word: die taalaanleerder se gesindheid teenoor en stereotipiese sienswyses van die sprekers van die teikentaal en die teikentaal self beinvloed die sukses van die verskil/ende stadia van die aanleerproses. Hierdie beinvloeding vind plaas omdat gesindhede motivering beinvloed en as sosio-affektiewe filter in die taalaanleerproses kan optree. Die implikasies van heersende gesindhede teenoor Afrikaans vir die onderrig en aanleer van die taal in 'n multitalige situasie word indringend bespreek. In the teaching of Afrikaans to and the acquisition of the language by non-mother tongue speakers in a multi-lingual environment, cognizance should be taken of prevailing attitudes: the attitudes of the learner towards the target language and his/her stereotypical perceptions of the target language and its speakers which influence the success of the language learning process in various stages. This influence takes place because attitudes affect motivation and can also act as a socio-ajjective filter in the language acquisition process. The implications of existing attitudes towards Afrikaans for the teaching and acquisition of the language in a multi-lingual situation are discussed in depth.

  1. Die ontwerp van ʼn Afrikaanse taakgebaseerde rekenaaronderrig ...

    African Journals Online (AJOL)

    Kate H

    gelewer word, is om die moontlike ontwerp van ʼn taakgebaseerde rekenaarprogram vir die kursus. Beginner Afrikaans Vlak 1 te ... to transfer the required amount of credits back to their home universities. The Language Centre ..... 3.1.1 Die tweeledige kanaal-aanname (“dual channel assumption”). Hierdie aanname ...

  2. Leibniz und die Psychophysik des Gehirns

    NARCIS (Netherlands)

    S. Tuinen (Sjoerd)

    2011-01-01

    textabstract1. Das Gehirn als Medium allen Denkens Die Probleme der Philosophie sind laut Deleuze niemals von sich aus philosophisch. Bereits eine Antwort auf die Frage Was ist Philosophie? setzt ein nicht-philosophisches 'Bild des Denkens' voraus, eine Art absoluten Hintergrund, in den die

  3. uniform van die staatspresidentswag - herkoms en tradisie

    African Journals Online (AJOL)

    A blue uniform was inter alia proposed in 1980 but finally rejected by the Prime Minister in 1984. Instructions were issued to put forth new ideas. All the arguments in ..... In 1896 Is die rang van kommandant van die Staatsartlllerie verhoog tot die van lultenant-kolonel. Henning Pretorlus, father and first commandant of the.

  4. Straatsburg en artikel 2 van die dordtse kerkorde

    Directory of Open Access Journals (Sweden)

    L. F. Schulze

    1966-03-01

    Full Text Available In art. 2 K.O. word daar vier soorte kerklike dienste on dcrskei, nl. „dié van die bedienaars van die Woord, dié van die professore aan die teologiese skool, die van die ouderlinge, en dié van die diakens”.

  5. Die skrywer. Esta Steyn. Kaapstad: Tafelberg, 2012. 214 pp. ISBN ...

    African Journals Online (AJOL)

    ningsromans in Duits, is die Christelike ele- mente en die humor. Die straatslim Anabella wat twee plaaswerkers aansê om nie die Here se naam te misbruik nie, toon kenmerke van die heldin in 'n Afrikaanse liefdesverhaal. Hierdie roman sal byval vind by lesers wat. Esta Steyn se vorige romans geniet het. Die humor in die ...

  6. Study of the impact of multiple weld repairs and associated stress-relief annealing on mechanical properties at elevated temperatures of large components made of the low-alloy steel 16Mo3; Untersuchung der Auswirkungen von mehrfachen Schweissreparaturen und damit verbundenen Spannungsarmgluehungen an Grossbauteilen aus 16Mo3 auf die Warmfestigkeitseigenschaften

    Energy Technology Data Exchange (ETDEWEB)

    Giller, Madeleine; Lehmann, Katrin [Siemens AG, Berlin (Germany). Energy Sector, Products, Gas Turbines

    2013-07-01

    This paper is related to 16Mo3, a low-alloy steel typical in the manufacture of large welded steel casings of heavy-duty gas turbine engines. The usual practice in manufacturing is to stress relieve these housings after fabrication welding. If, however, weld imperfections are detected by non-destructive testing, weld repairs are performed, followed by additional stress-relief heat treatments. The methods applied were used to detect possible embrittlement by secondary carbide precipitation and to finally draw conclusions on material changes. The critical area of a weld is the heat affected zone. In this area a worsening of the stress condition in connection with a change in carbide precipitation and thus a decrease in creep rupture strength occurs. A concrete alloy composition and heat treatment adapted to the precipitation behavior are important, because they determine the type, amount and distribution of the resulting carbides. (orig.)

  7. Studie: Die Generation Y und deren organisatorische Implikationen

    OpenAIRE

    Klein, Helmut

    2016-01-01

    Die vorliegende Studie betrifft die Gen. Y und ihre spezifischen Anforderungen an die Unternehmensorganisation. Im Ergebnis einer durchgeführten Befragung ist festzuhalten, dass die Gen. Y die Kernkompetenzen eines Managers verstärkt einfordert und eine hohe Betreuungsintensität verlangt. Dies hat Auswirkungen auf die Führungsspanne, Planung und Kontrolle von Aufgaben, die Gestaltung der vertikalen und horizontalen Prozesse sowie die Zusammensetzung von Teamarbeitsformen. Projektarbeit sowie ...

  8. Die lewensvatbaarheid van 'n slaghuisfranchise / deur Johan Smit

    OpenAIRE

    Smit, Johan

    2009-01-01

    Die Suid-Afrikaanse rooivleisindustrie is lomp en wyd. Een van die redes vir hierdie toedrag van sake is die verskeie rolspelers in die industrie. 'n Moontlike oplossing vir hierdie probleem is die vertikale integrasie-sisteem gerugsteun deur 'n lewensvatbare franchise in die kleinhandelsektor. Die studie fokus op die lewensvatbaarheid van 'n slaghuisfranchise. Daar moet egter ook bepaal word of 'n slaghuis wei gefranchise kan word, voordat die lewensvatbaarheid van 'n slaghuisfranchise be...

  9. Paleontologie en die Suid-Afrikaanse samelewing vandag

    OpenAIRE

    Durand, JF

    2013-01-01

    Die huidige oënskynlike ondersteuning van paleontologie deur die regering en die insluiting en beklemtoning van evolusie in die skoolleerplan word bespreek in die lig van sekere politieke ontwikkelings wat oor die laaste twee dekades in Suid-Afrika plaasgevind het. Dit sluit die regering se ondersteuning van paleontologiese ontdekkings in die media, die ontwikkeling van fossielterreine en paleotoerisme in. Ondanks hierdie positiewe inisiatiewe gedy paleontologie nie in Suid-Afrika nie en is d...

  10. DIE PLEK VAN ISRAEL IN ONS TEOLOGIES-KERKLIKE ...

    African Journals Online (AJOL)

    Test

    as 'n volk in daardie sin aangemerk kon word, en in die O.T. Israel dan ook 'n paar maal, teen die reël wat ons as beginnende studente geleer het,. 1) Die leser vind hier die lesing, deur die skrywer op 29 Februarie 1956 vir die Predikante- vergadering te Pretoria gehou. Die formulering van die titel was van die skriba van.

  11. Artikel 2 van die Nederlandse Geloofsbelydenis as geloofsvooronderstelling in die gesprek tussen wetenskap en geloof

    Directory of Open Access Journals (Sweden)

    Jan A. Erasmus

    2014-09-01

    Full Text Available Artikel 2 van die Nederlandse Geloofsbelydenis bely dat God deur twee middele geken word, te wete deur middel van die skepping, onderhouding en regering van die wêreld (waaronder die wetenskap en deur die heilige en goddelike Woord (die Bybel. Hierdie belydenis is van groot belang vir die gesprek tussen Wetenskap en Teologie. In hierdie artikel word gepoog om die verskille, maar ook die ooreenkomste tussen hierdie twee middele van openbaring uit te lig, elkeen tot sy reg te laat kom, maar hulle ook in balans met mekaar te stel. Die wyse waarop te werk gegaan word, is die volgende: eers word gestel wat vooronderstellings is, asook die plek wat vooronderstellings in die beoefening van wetenskap sowel as geloof inneem. Daarna word nagevors watter perspektiewe artikel 2 van die Nederlandse Geloofsbelydenis as geloofsvooronderstelling vir die wetenskaps- en teologiebeoefening respektiewelik bied. Hieruit word ’n aantal gevolgtrekkings gemaak wat kan help om die problematiek in die wetenskap-geloofsgesprek op te los. Die kernbevinding van hierdie artikel is die volgende: Vanweë die verskil in die aard en die doel tussen Bybelfeite en wetenskaplike navorsingsresultate kan en sal klaarblyklike harmonieprobleme tussen die Skrif en die wetenskap ontstaan. Hierdie is egter slegs klaarblyklike probleme, omdat ’n verrekening van die verskil in die aard en die bedoeling van die wetenskapresultate en die Bybelfeite hierdie probleem sal oplos. Article 2 of the Belgic Confession as faith presupposition in the science-faith debate. Article 2 of the Belgic Confession confesses that God can be known by two means: firstly by studying the creation, preservation and government of the universe (i.e. science and secondly by studying the Word of God (the Bible. This confession is very important for the discussion between science and faith. In this article the similarities, but also the differences between these two means of revelation are researched. The aim is to

  12. On electrical resistivity of AISI D2 steel during various stages of cryogenic treatment

    Science.gov (United States)

    Lomte, Sachin Vijay; Gogte, Chandrashekhar Laxman; Peshwe, Dilip

    2012-06-01

    The effect of dislocation densities and residual stresses is well known in tool steels. Measurement of electrical resistivity in order to monitor dislocation densities or residual stresses has seldom been used in investigating the effect of cryogenic treatment on tool steels. Monitoring residual stresses during cryogenic treatment becomes important as it is directly related to changes due to cryogenic treatment of tool steels. For high carbon high chromium (HCHC- AISI D2) steels, not only wear resistance but dimensional stability is an important issue as the steels are extensively used in dies, precision measuring instruments. This work comprises of study of measurement of electrical resistivity of AISI D2 steel at various stages of cryogenic treatment. Use of these measurements in order to assess the dimensional stability of these steels is discussed in this paper.

  13. Die wet is evangelie: Die Heidelbergse Kategismus steeds aktueel na 450 jaar

    Directory of Open Access Journals (Sweden)

    Piet Strauss

    2013-09-01

    Full Text Available In die denke van Martin Luther bestaan daar spanning tussen die wet van God en die evangelie. Vir Luther is liefde die eie werk en die wet die vreemde werk van God. Daarteenoor integreer of versoen Johannes Calvyn God se wet met die evangelie. Hy vertolk die openingswoorde van die wet byvoorbeeld as liefdevol en bevrydend en daarom evangelies. Calvyn beskou die wet as die manier waarop ’n Christen sy liefde vir God uitleef en sy dankaarheid teenoor God vir sy verlossing betoon. Calvyn se siening oor die verhouding tussen die wet en die evangelie het ’n betekenisvolle invloed op die Heidelbergse Kategismus se formulering ten opsigte van hierdie saak. Volgens die Kategismus is die wet evangelie, of die vorm wat die evangelie in die lewe van die mens aanneem. In the thought of Martin Luther tension exists between the law of God and the gospel. Luther regards love as the own work of God and the law as something strange to the Lord. John Calvin, however, integrates Gods law and the gospel to the extent that the opening words of the ten commandments are regarded as words of love and redemption and therefore evangelical. To Calvin the law becomes the way in which a converted Christian lives and shows his gratitude to God for his salvation. Calvin’s view on the relationship between law and gospel had a significant influence on the way in which the Heidelberg Cathecism formulates these two concepts. For the Cathecism the law is gospel or the form in which the gospel takes shape in human life.

  14. Die impak van die verbond op 'n paradigma vir pastoraat: research ...

    African Journals Online (AJOL)

    Die verbond het 'n meer omvattende impak op pastorale sorg as ander paradigmas. Genoemde stelling word in hierdie artikel beredeneer. Daar word aangetoon dat die inhoud wat aan die gelowige gekommunikeer word, asook die tegnieke wat gebruik word, deur 'n verbondmatige paradigma vir pastorale sorg be?nvloed ...

  15. Die rol van kapitaal in die ekonomiese groei en ontwikkeling van onderontwikkelde gebiede*

    Directory of Open Access Journals (Sweden)

    F. J. du Plessis

    1961-03-01

    Full Text Available In die teorie oor ekonomiese groei speel kapitaal ’n besonder prominente rol. Kapitaal met die daarby behorende tegnologiese ontwikkeling, word beskou as die belangrikste enkele faktor verantwoordelik vir die bereiking en instandhouding van ’n „ten voile ontwikkelde” volkshuishouding.

  16. Die taak van akademiese geletterdheid/hede binne die konteks van ...

    African Journals Online (AJOL)

    Opsomming. Die vestiging van Akademiese Geletterdheid by tersiêre instansies in Suid-Afrika het gegroei uit die besef dat 'n goedontwikkelde akademiese taalvermoë essensieel is vir akademiese prestasie. Gepubliseerde literatuur getuig van die belangrike verskuiwings wat oor die afgelope aantal dekades plaasgevind ...

  17. Ek wil hier graag van die geleentheid gebruik maak am die ...

    African Journals Online (AJOL)

    die wildlewe am van die jagters nie eers mel- ding te maak nie en in Lucas se werk kan hulle ure van genot deurbring. Wat ons veral in Lucas se publikasie interes- seer is sy deelname aan die agste grensoor~' log (1850-1853), sy aantekeninge in verband met die slag by Berea (20 Oesember 1852) en sy indrukke van ...

  18. Die dinamika van die beperkte drie-deeltjie-probleem in sterrekunde

    Directory of Open Access Journals (Sweden)

    Keegan D. Anderson

    2011-09-01

    Full Text Available Die beperkte drie-deeltjie-probleem is een van die oudste probleme in klassieke fisika en is alvir ongeveer die afgelope honderd jaar bestudeer. Die probleem is nie oplosbaar op ‘n geslote analitiese wyse nie, alhoewel ’n oneindige reeks oplossing bestaan.

  19. Die reg van die homoseksuele ouer om beheer en toesig oor 'n kind ...

    African Journals Online (AJOL)

    Administrator

    regtens seëvier sodat die grondwetlike verbod op onbillike diskriminasie teen mense op grond van hul seksuele georiënteerdheid so .... gerig teen die homoseksueel self en die homoseksuele daad wat hy/sy beoefen, maar dat daar ook gediskrimineer ..... Die Uniform Marriage and Divorce Act,. 60 aangeneem in verskeie ...

  20. Die huwelik in die eerste-eeuse Mediterreense wêreld (III): Jesus en ...

    African Journals Online (AJOL)

    p1243322

    30 Jan 2007 ... description of what marriage, betrothal, adultery, divorce and ..... egbreuk teen wie? Wanneer daar in ag geneem word dat 'n man in die eerste- eeuse Mediterreense wêreld nie egbreuk teenoor sy vrou kon pleeg nie (kyk ... volg egbreuk teen die vrou in die huwelik beteken – al het die vrou owerspel.