The development of new metal powders for the selective laser sintering process is considered unde... more The development of new metal powders for the selective laser sintering process is considered underlining the importance of an integrated approach considering powder metal technologies, the specific manufacturing process and some empirical correlations that have been found in the field. Some relevant physical parameters, flow rate, density and thermal conductivity are considered, together with some elementary thermophysical requirements of the process. The corresponding sintered body properties are presented, with in mind testing procedures in the field of sintered metals. Industrial and developing processes of powder production-divided in primary and secondary powder treatments-are reviewed, with the aim of identifying improved or tailored production routes for industrial powders for this rapid prototyping technique. Examples of applications of laboratory developed powders are given, together with the properties of the laser sintered bodies.
Http Dx Doi Org 10 1080 13642819308217947, Aug 20, 2006
Abstract The entropy approach to viscosity proposed by Adam and Gibbs underlines an exponential i... more Abstract The entropy approach to viscosity proposed by Adam and Gibbs underlines an exponential influence of the entropy difference between solid and liquid on the (undercooled) melt viscosity. We propose to consider two different trends for the specific heat difference between solid and liquid as for pure metallic melts and glass-forming metallic melts, which both support a discontinuity at the ideal glass transition temperature like the well-known empirical Vogel-Fulcher equation. In particular we check for two glass- ...
The development of new metal powders for the selective laser sintering process is considered unde... more The development of new metal powders for the selective laser sintering process is considered underlining the importance of an integrated approach considering powder metal technologies, the specific manufacturing process and some empirical correlations that have been found in the field. Some relevant physical parameters, flow rate, density and thermal conductivity are considered, together with some elementary thermophysical requirements of the process. The corresponding sintered body properties are presented, with in mind testing procedures in the field of sintered metals. Industrial and developing processes of powder production-divided in primary and secondary powder treatments-are reviewed, with the aim of identifying improved or tailored production routes for industrial powders for this rapid prototyping technique. Examples of applications of laboratory developed powders are given, together with the properties of the laser sintered bodies.
The possibility of obtaining metal(M)-oxide(RO) nanocomposites by solid state reduction reactions... more The possibility of obtaining metal(M)-oxide(RO) nanocomposites by solid state reduction reactions of "MO" oxides with a suitable reductant "R" was recently established [1]. Reduction of Fe203 has been obtained by reductants such as A1, B, Cr, and Si [2]. The resulting powders are (Fe)-(oxide) nanocomposites. The toughening of ceramics by ductile reinforcements, for example by metal-oxide composites, are being increasingly considered [3]. In the present work, a study of the kinetics of formation of tx-A12Oa-Fe nanocomposites by room temperature ball ...
Acta otorhinolaryngologica Italica : organo ufficiale della Società italiana di otorinolaringologia e chirurgia cervico-facciale
Capacity and temporal characteristics of auditory short-term memory have been investigated throug... more Capacity and temporal characteristics of auditory short-term memory have been investigated through a simple multi-tonal sequence paradigm in five normally hearing subjects. They were required to judge whether the tonal sequence contained or not a tone probe following the sequence. Performance was evaluated relative to the sequence length (2, 4, 6 stimuli) and sequence-probe interval (1, 3, 6 s.). The subjects' performance has been proven to be mainly dependent on the number of the sequence components (90% of the explained variance), while sequence-probe interval represents a factor of minor weight. Furthermore, a strong recency effect has been shown for the last sequence component, extending to the preceding components in dependence of the sequence-probe interval. Contrasting to studies on the verbal short-term memory, a primary effect has been not demonstrated. As these results reflect the typical effects of auditory short-term memory, it is likely that memory tests based on si...
This paper presents some practical considerations on finishing of parts made by direct metal lase... more This paper presents some practical considerations on finishing of parts made by direct metal laser sintering (DMLS). The main process capabilities limitations of this promising rapid tooling technique are in fact in the surface roughness of the produced parts. This fact hinders the introduction of DMLS as a widely employed industrial process, especially for what concerns the production of moulds and inserts and allows their use only as preseries tools in injection moulding of plastics, since the requirements for preseries tools are worse than ...
Abstract: Two of the key factors in the densification of powders properties in sintering processe... more Abstract: Two of the key factors in the densification of powders properties in sintering processes-the green body density and green body strength-are studied with the purpose of giving appropriate empirical modeling of the laser sintering of uncoated metal powders. Some proposals for the characterisation of technological properties of powders for selective laser sintering of uncoated powders are discussed in this framework for establishing possible standards for the development of new or improved powders. Methods for the ...
The development of new metal powders for the selective laser sintering process is considered unde... more The development of new metal powders for the selective laser sintering process is considered underlining the importance of an integrated approach considering powder metal technologies, the specific manufacturing process and some empirical correlations that have been found in the field. Some relevant physical parameters, flow rate, density and thermal conductivity are considered, together with some elementary thermophysical requirements of the process. The corresponding sintered body properties are presented, with in mind testing procedures in the field of sintered metals. Industrial and developing processes of powder production-divided in primary and secondary powder treatments-are reviewed, with the aim of identifying improved or tailored production routes for industrial powders for this rapid prototyping technique. Examples of applications of laboratory developed powders are given, together with the properties of the laser sintered bodies.
Http Dx Doi Org 10 1080 13642819308217947, Aug 20, 2006
Abstract The entropy approach to viscosity proposed by Adam and Gibbs underlines an exponential i... more Abstract The entropy approach to viscosity proposed by Adam and Gibbs underlines an exponential influence of the entropy difference between solid and liquid on the (undercooled) melt viscosity. We propose to consider two different trends for the specific heat difference between solid and liquid as for pure metallic melts and glass-forming metallic melts, which both support a discontinuity at the ideal glass transition temperature like the well-known empirical Vogel-Fulcher equation. In particular we check for two glass- ...
The development of new metal powders for the selective laser sintering process is considered unde... more The development of new metal powders for the selective laser sintering process is considered underlining the importance of an integrated approach considering powder metal technologies, the specific manufacturing process and some empirical correlations that have been found in the field. Some relevant physical parameters, flow rate, density and thermal conductivity are considered, together with some elementary thermophysical requirements of the process. The corresponding sintered body properties are presented, with in mind testing procedures in the field of sintered metals. Industrial and developing processes of powder production-divided in primary and secondary powder treatments-are reviewed, with the aim of identifying improved or tailored production routes for industrial powders for this rapid prototyping technique. Examples of applications of laboratory developed powders are given, together with the properties of the laser sintered bodies.
The possibility of obtaining metal(M)-oxide(RO) nanocomposites by solid state reduction reactions... more The possibility of obtaining metal(M)-oxide(RO) nanocomposites by solid state reduction reactions of "MO" oxides with a suitable reductant "R" was recently established [1]. Reduction of Fe203 has been obtained by reductants such as A1, B, Cr, and Si [2]. The resulting powders are (Fe)-(oxide) nanocomposites. The toughening of ceramics by ductile reinforcements, for example by metal-oxide composites, are being increasingly considered [3]. In the present work, a study of the kinetics of formation of tx-A12Oa-Fe nanocomposites by room temperature ball ...
Acta otorhinolaryngologica Italica : organo ufficiale della Società italiana di otorinolaringologia e chirurgia cervico-facciale
Capacity and temporal characteristics of auditory short-term memory have been investigated throug... more Capacity and temporal characteristics of auditory short-term memory have been investigated through a simple multi-tonal sequence paradigm in five normally hearing subjects. They were required to judge whether the tonal sequence contained or not a tone probe following the sequence. Performance was evaluated relative to the sequence length (2, 4, 6 stimuli) and sequence-probe interval (1, 3, 6 s.). The subjects' performance has been proven to be mainly dependent on the number of the sequence components (90% of the explained variance), while sequence-probe interval represents a factor of minor weight. Furthermore, a strong recency effect has been shown for the last sequence component, extending to the preceding components in dependence of the sequence-probe interval. Contrasting to studies on the verbal short-term memory, a primary effect has been not demonstrated. As these results reflect the typical effects of auditory short-term memory, it is likely that memory tests based on si...
This paper presents some practical considerations on finishing of parts made by direct metal lase... more This paper presents some practical considerations on finishing of parts made by direct metal laser sintering (DMLS). The main process capabilities limitations of this promising rapid tooling technique are in fact in the surface roughness of the produced parts. This fact hinders the introduction of DMLS as a widely employed industrial process, especially for what concerns the production of moulds and inserts and allows their use only as preseries tools in injection moulding of plastics, since the requirements for preseries tools are worse than ...
Abstract: Two of the key factors in the densification of powders properties in sintering processe... more Abstract: Two of the key factors in the densification of powders properties in sintering processes-the green body density and green body strength-are studied with the purpose of giving appropriate empirical modeling of the laser sintering of uncoated metal powders. Some proposals for the characterisation of technological properties of powders for selective laser sintering of uncoated powders are discussed in this framework for establishing possible standards for the development of new or improved powders. Methods for the ...
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Papers by Fabio Miani