The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jörg Schwedes - One of the best experts on this subject based on the ideXlab platform.
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breaking characteristics of different materials and their effect on stress intensity and stress number in stirred media mills
Powder Technology, 2002Co-Authors: Arno Kwade, Jörg SchwedesAbstract:The comminution process in stirred media mills is determined mainly by the number of stress events in the grinding chamber and by the intensity acting at these stress events. For a certain stress intensity, a certain relation between the product Fineness and the number of stress events exists. Since the product of stress number and stress intensity is a measure for the specific energy, for each stress intensity, a certain relation between product Fineness and specific energy also exists. The effect of stress intensity, stress number and specific energy on the product Fineness is determined by the breakage characteristic of the material. With respect to the breakage characteristic, two main groups can be distinguished: firstly, deagglomeration and disintegration and secondly, grinding of crystalline materials. Among others, the breakage characteristics determine how strongly the specific energy consumption is affected by the stress intensity.
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comminution of ceramics in stirred media mills and wear of grinding beads
Powder Technology, 1999Co-Authors: M Becker, Jörg SchwedesAbstract:Abstract Experimental investigations on the comminution of fused corundum and silicon carbide show that comminution and wear behaviour of ceramic grinding beads are affected by the structural constitution of grinding beads. For grinding beads composed of large primary particles, the achievable product Fineness seems to be limited by the size of the primary particles. For the grinding beads composed of small primary particles, the product Fineness is not limited by the size of the primary particles. The relation between specific energy requirement and product Fineness is essentially affected by the amount of grinding bead wear. The wear of grinding beads is determined by the structure and the hardness of beads as well as by the hardness and the shape of the feed particles.
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motion and stress intensity of grinding beads in a stirred media mill part 2 stress intensity and its effect on comminution
Powder Technology, 1996Co-Authors: Arno Kwade, Lutz Blecher, Jörg SchwedesAbstract:Experimental investigations concerning the comminution of limestone in a stirred media mill have been carried out. The results show that the circumferential velocity of the stirrer discs as well as the density and the size of the grinding beads affect the specific energy consumption necessary to achieve the required product Fineness. The influence of these three operating parameters on the comminution result can be fully described by the stress intensity of the grinding beads. Therefore, specific energy consumption and stress intensity of the grinding beads are the comprehensive influencing variables on the comminution of limestone in stirred media mills. It is expected that this relationship is also valid for the comminution of other materials in stirred media mills. For a fixed specific energy input, an optimum stress intensity exists, for which the finest product is achieved. With increasing specific energy input, and therefore increasing product Fineness, the optimum stress intensity decreases. Since the specific energy is proportional to the product of stress intensity and stress frequency, the comminution result can also be correlated to the stress frequency and the stress intensity. With increasing stress intensity, the stress frequency required for a certain product Fineness decreases.
Arno Kwade - One of the best experts on this subject based on the ideXlab platform.
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effect of important precipitation process parameters on the redispersion process and the micromechanical properties of precipitated silica
Chemical Engineering & Technology, 2009Co-Authors: Carsten Schilde, T Gothsch, Kerstin Quarch, Matthias Kind, Arno KwadeAbstract:In the past, the importance of the industrial mass production of high-quality products and specialty chemicals by precipitation increased rapidly. In the industry, usually larger aggregates are produced and in order to produce colloidal systems with the desired properties, a more or less intense dispersion of the precipitated particles is necessary. The micromechanical properties such as the maximum indentation force, the plastic and elastic deformation energy, and the strength can give information on the product and the efficiency of the dispersion process. Generally, the temperature, as one of the most important parameters of the semi-batch precipitation process of silica, was varied in order to change the structure, the primary particle size, the aggregate size, and the primary particle interactions in the aggregates. Dispersion of the precipitated silica in a stirred media mill and a dissolver show that the higher the precipitation temperature, the higher is the product Fineness and, thus, the smaller is the strength of the aggregates. The reason for this effect is the increase of the primary particle size and the decrease of the solid bonds with increasing precipitation temperature. Because of higher stress intensities, the product Fineness in a stirred media mill is considerably higher than in the dissolver. In principal, the maximum achievable product Fineness and the energy efficiency of the dispersion process increase with decreasing particle strength and maximum indentation force. Besides the maximum indentation force, the maximum achievable product Fineness and the energy efficiency of the dispersion process increase with increasing quotient of plastic and elastic deformation energy.
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breaking characteristics of different materials and their effect on stress intensity and stress number in stirred media mills
Powder Technology, 2002Co-Authors: Arno Kwade, Jörg SchwedesAbstract:The comminution process in stirred media mills is determined mainly by the number of stress events in the grinding chamber and by the intensity acting at these stress events. For a certain stress intensity, a certain relation between the product Fineness and the number of stress events exists. Since the product of stress number and stress intensity is a measure for the specific energy, for each stress intensity, a certain relation between product Fineness and specific energy also exists. The effect of stress intensity, stress number and specific energy on the product Fineness is determined by the breakage characteristic of the material. With respect to the breakage characteristic, two main groups can be distinguished: firstly, deagglomeration and disintegration and secondly, grinding of crystalline materials. Among others, the breakage characteristics determine how strongly the specific energy consumption is affected by the stress intensity.
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motion and stress intensity of grinding beads in a stirred media mill part 2 stress intensity and its effect on comminution
Powder Technology, 1996Co-Authors: Arno Kwade, Lutz Blecher, Jörg SchwedesAbstract:Experimental investigations concerning the comminution of limestone in a stirred media mill have been carried out. The results show that the circumferential velocity of the stirrer discs as well as the density and the size of the grinding beads affect the specific energy consumption necessary to achieve the required product Fineness. The influence of these three operating parameters on the comminution result can be fully described by the stress intensity of the grinding beads. Therefore, specific energy consumption and stress intensity of the grinding beads are the comprehensive influencing variables on the comminution of limestone in stirred media mills. It is expected that this relationship is also valid for the comminution of other materials in stirred media mills. For a fixed specific energy input, an optimum stress intensity exists, for which the finest product is achieved. With increasing specific energy input, and therefore increasing product Fineness, the optimum stress intensity decreases. Since the specific energy is proportional to the product of stress intensity and stress frequency, the comminution result can also be correlated to the stress frequency and the stress intensity. With increasing stress intensity, the stress frequency required for a certain product Fineness decreases.
Das A. - One of the best experts on this subject based on the ideXlab platform.
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Study on physiological comfort of fabrics made up of structurally modified friction-spun yarns: Part I - vapour transmission
National Institute of Science Communication and Information Resources, 2010Co-Authors: Singh K. V. P., Chatterjee A., Das A.Abstract:The effect of sheath fibre proportion, fibre Fineness, and yarn Fineness on physiological comfort related properties such as air permeability, water vapour permeability and thermal conductivity of Dref-III friction-spun yarn fabrics has been studied with an objective to analyse the feasibility of modified yarns for apparel end use. Samples have been prepared using polyester filament fibre as core, viscose staple fibre as secondary core and water soluble polyvinyl alcohol as sheath. It is observed that the structural modification of yarn influences the comfort related properties, effecting the vapour transmission behavior
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Study on physiological comfort of fabrics made up of structurally modified friction-spun yarns: Part I – Vapour transmission
'CSIRO Publishing', 2010Co-Authors: Singh K. V. P., Chatterjee A., Das A.Abstract:31-37The effect of sheath fibre proportion, fibre Fineness, and yarn Fineness on physiological comfort related properties such as air permeability, water vapour permeability and thermal conductivity of Dref-III friction-spun yarn fabrics has been studied with an objective to analyse the feasibility of modified yarns for apparel end use. Samples have been prepared using polyester filament fibre as core, viscose staple fibre as secondary core and water soluble polyvinyl alcohol as sheath. It is observed that the structural modification of yarn influences the comfort related properties, effecting the vapour transmission behavior
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Study on physiological comfort of fabrics made up of structurally modified friction-spun yarns: Part II – Liquid transmission
'CSIRO Publishing', 2010Co-Authors: Singh K. V. P., Chatterjee A., Das A.Abstract:134-138Dref III friction-spun yarn has been structurally modified using polyester filament fibre as core, viscose staple fibre as secondary core and water soluble poly (vinyl alcohol) as sheath. The yarn is then treated with hot water to wash out PVA in the sheath, leaving the twistless viscose staple fibres on the surface. Effect of sheath fibre proportion, fibre Fineness and yarn Fineness on physiological comfort related properties affecting the liquid transmission behaviour, such as wickability and water absorbency, has been studied. It is observed that the structural modification of yarn influences the liquid transmission behaviour of fabric. All the three factors studied significantly affect the liquid transmission behaviour of the fabric
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Study on physiological comfort of fabrics made up of structurally modified friction-spun yarns: Part II - liquid transmission
National Institute of Science Communication and Information Resources, 2010Co-Authors: Singh K. V. P., Chatterjee A., Das A.Abstract:Dref III friction-spun yarn has been structurally modified using polyester filament fibre as core, viscose staple fibre as secondary core and water soluble poly (vinyl alcohol) as sheath. The yarn is then treated with hot water to wash out PVA in the sheath, leaving the twistless viscose staple fibres on the surface. Effect of sheath fibre proportion, fibre Fineness and yarn Fineness on physiological comfort related properties affecting the liquid transmission behaviour, such as wickability and water absorbency, has been studied. It is observed that the structural modification of yarn influences the liquid transmission behaviour of fabric. All the three factors studied significantly affect the liquid transmission behaviour of the fabric
Shuhua Liu - One of the best experts on this subject based on the ideXlab platform.
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influence of Fineness on hydration kinetics of supersulfated cement
Thermochimica Acta, 2015Co-Authors: Shuhua Liu, Lu Wang, Yuxin Gao, Wan TangAbstract:Abstract Hydration heat evolution rate and quantity of supersulfated cements (SSCs) with three different specific surface areas (335 m 2 /kg, 445 m 2 /kg and 518 m 2 /kg) were measured at 25 °C by isothermal calorimetry. The hydration heat evolution quantity of SSCs improves with the increase of cement Fineness, but is much lower than that of ordinary Portland cement. The hydration of supersulfated cement is accelerated by the elevated Fineness, and the hydration process of supersulfated cement after induction period was divided into three periods, nucleation and crystal growth (NG), phase boundary reaction (I), and diffusion (D), which are well simulated through Krstulovic–Dabic model. The connecting points of NG process and I process, I process and D process both decrease with the increase of Fineness which shows that the second exothermic peak is in advance. I process also decreases with the increase of Fineness, which indicates that I process is accelerated by Fineness. The hydration of supersulfated cement is sensitive to Fineness, especially for the specific surface area reaching up to 518 m 2 /kg.
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Influence of Fineness on the cementitious properties of steel slag
Journal of Thermal Analysis and Calorimetry, 2014Co-Authors: Shuhua LiuAbstract:In this paper, the influence of Fineness on the cementitious properties of steel slag and the properties of cement containing steel slag with different Finenesses were investigated. The results show that increasing the Fineness can significantly enhance the early as well as the late cementitious properties of steel slag. However, the early hydrations of cement and steel slag tend to hinder each other especially in the case of large steel slag replacement and high Fineness of steel slag. Therefore, increasing Fineness of steel slag cannot improve the early cementitious properties of the cement containing steel slag. At 28 days, the hydrations of steel slag and cement tend to promote each other. Increasing the Fineness of steel slag enhances the late cementitious properties of the cement containing steel slag significantly.
Singh K. V. P. - One of the best experts on this subject based on the ideXlab platform.
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Study on physiological comfort of fabrics made up of structurally modified friction-spun yarns: Part I - vapour transmission
National Institute of Science Communication and Information Resources, 2010Co-Authors: Singh K. V. P., Chatterjee A., Das A.Abstract:The effect of sheath fibre proportion, fibre Fineness, and yarn Fineness on physiological comfort related properties such as air permeability, water vapour permeability and thermal conductivity of Dref-III friction-spun yarn fabrics has been studied with an objective to analyse the feasibility of modified yarns for apparel end use. Samples have been prepared using polyester filament fibre as core, viscose staple fibre as secondary core and water soluble polyvinyl alcohol as sheath. It is observed that the structural modification of yarn influences the comfort related properties, effecting the vapour transmission behavior
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Study on physiological comfort of fabrics made up of structurally modified friction-spun yarns: Part I – Vapour transmission
'CSIRO Publishing', 2010Co-Authors: Singh K. V. P., Chatterjee A., Das A.Abstract:31-37The effect of sheath fibre proportion, fibre Fineness, and yarn Fineness on physiological comfort related properties such as air permeability, water vapour permeability and thermal conductivity of Dref-III friction-spun yarn fabrics has been studied with an objective to analyse the feasibility of modified yarns for apparel end use. Samples have been prepared using polyester filament fibre as core, viscose staple fibre as secondary core and water soluble polyvinyl alcohol as sheath. It is observed that the structural modification of yarn influences the comfort related properties, effecting the vapour transmission behavior
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Study on physiological comfort of fabrics made up of structurally modified friction-spun yarns: Part II – Liquid transmission
'CSIRO Publishing', 2010Co-Authors: Singh K. V. P., Chatterjee A., Das A.Abstract:134-138Dref III friction-spun yarn has been structurally modified using polyester filament fibre as core, viscose staple fibre as secondary core and water soluble poly (vinyl alcohol) as sheath. The yarn is then treated with hot water to wash out PVA in the sheath, leaving the twistless viscose staple fibres on the surface. Effect of sheath fibre proportion, fibre Fineness and yarn Fineness on physiological comfort related properties affecting the liquid transmission behaviour, such as wickability and water absorbency, has been studied. It is observed that the structural modification of yarn influences the liquid transmission behaviour of fabric. All the three factors studied significantly affect the liquid transmission behaviour of the fabric
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Study on physiological comfort of fabrics made up of structurally modified friction-spun yarns: Part II - liquid transmission
National Institute of Science Communication and Information Resources, 2010Co-Authors: Singh K. V. P., Chatterjee A., Das A.Abstract:Dref III friction-spun yarn has been structurally modified using polyester filament fibre as core, viscose staple fibre as secondary core and water soluble poly (vinyl alcohol) as sheath. The yarn is then treated with hot water to wash out PVA in the sheath, leaving the twistless viscose staple fibres on the surface. Effect of sheath fibre proportion, fibre Fineness and yarn Fineness on physiological comfort related properties affecting the liquid transmission behaviour, such as wickability and water absorbency, has been studied. It is observed that the structural modification of yarn influences the liquid transmission behaviour of fabric. All the three factors studied significantly affect the liquid transmission behaviour of the fabric