P. Regenfuss, A. Streek, L. Hartwig, S. Klötzer, Th. Brabant, M. Horn, R. Ebert and H. Exner
The purpose of the paper is the elucidation of certain mechanisms of laser material processing in general and laser micro sintering in particular. One major intention is to…
Abstract
Purpose
The purpose of the paper is the elucidation of certain mechanisms of laser material processing in general and laser micro sintering in particular. One major intention is to emphasize the synergism of the various effects of q‐switched laser pulses upon metal and ceramic powder material and to point out the non‐equilibrium character of reaction steps.
Design/methodology/approach
Recent results and observations, obtained in development of “laser micro sintering,” are surveyed and analyzed. By breaking down the overall process into relevant steps and considering their possible kinetics, an approach is made towards interpreting specific phenomena of laser micro sintering. Thermodynamics upon heating of the material as well as its photo‐electronic response to the incident radiation are considered.
Findings
The findings corroborate a model whereby short pulses of high intensity provide non‐equilibrium pressure conditions at the location of incidence, that allow for the melting of metal powder with an almost immediate expansion of a plasma and/or vapor bulb. Thereby the molten material is condensed and propelled towards the substrate. A final boiling eruption after each pulse is the reason for the morphology of the laser micro‐sintered surfaces and can prevent oxidation when the process is conducted under normal atmosphere. In sintering of ceramics, the short pulsed and intensive radiation increases the chance to excite the material even with photon energies below the bandgap value and it lowers the risk of running into a destructive avalanche.
Research limitations/implications
Owing to the stochastic character of the respective sintering event, that is initiated by each individual pulse, the gathered data are not suitable yet for the formulation of an exact quantitative function between sintering behavior and laser parameters.
Practical implications
The qualitative findings yield a good rule of thumb for the choice of parameters in laser sintering on a micrometer scale and the model is conducive for advanced interpretation of other phenomena in laser material processing besides sintering.
Originality/value
The kinetics and thermodynamics of laser sintering with q‐switched pulses are approached by a qualitative explanation. The heterogeneous and non‐equilibrium character of the processes is taken into account; this character is often neglected by researchers in the area.
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P. Regenfuss, L. Hartwig, S. Klötzer, R. Ebert, Th. Brabant, T. Petsch and H. Exner
Examples are given for the technical applicability of a novel development of selective laser sintering called “laser micro sintering”.
Abstract
Purpose
Examples are given for the technical applicability of a novel development of selective laser sintering called “laser micro sintering”.
Design/methodology/approach
Together with a specific method to produce powder layers, the controlled application of pulsed radiation for the processing of sub‐μm grained metal powders was exploited to produce micro‐tools with a heretofore unattained structural resolution.
Findings
High resolution micro bodies are displayed. Instruments could be generated which proved to fulfil their designation as grip bits for micro manipulators. The micro‐bodies can be generated detachably from or firmly fixed to the construction substrate. The material of the generated bodies withstands the traction forces when used as an injection mold for polymer casts.
Research limitations/implications
Densities and structural resolutions can still be improved especially with a newly updated version of the equipment. Laser micro sintering of materials, other than metal (e.g. ceramics), has still to be developed. The introduction of the equipment and the technique into the market is on its way.
Practical implications
Micro‐tools can be generated with an overall structural resolution of 30 μm and with all the advantages of a freedom technique.
Originality/value
The paper informs the technical community on a new novel modification of the freeform technique selective laser sintering, demonstrating the solution of some problems that have hampered the progress of metal laser into resolution ranges below 100 μm. It also supplies evidence for the technical applicability.
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Lucila Sánchez Boado, Raquel Maria Fretes and Luis Alberto Brumovsky
The purpose of this study was to evaluate in vivo the bioavailability of the Ilex paraguariensis polyphenols due to total polyphenols and changes in antioxidant capacity (AOC) in…
Abstract
Purpose
The purpose of this study was to evaluate in vivo the bioavailability of the Ilex paraguariensis polyphenols due to total polyphenols and changes in antioxidant capacity (AOC) in human plasma after an acute intake of 300 ml of an infusion of yerba maté (YM) for 120 minutes. Also, we evaluated the variation of plasma protein or plasma uric acid after the acute intake of YM infusion.
Design/methodology/approach
Seventeen healthy young volunteers participated in the determining plasma of total polyphenols concentration (TPC, Folin-Ciocalteu method), plasma AOC for ferric reducing antioxidant power (FRAP) and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid diammonium salt [ABTS] methods), plasmatic uric acid and plasma total protein over the 120 minutes test.
Findings
It was found that the bioavailability of YM polyphenols during 120 minutes was 49.3 ± 11.9 per cent, the TPC was increased to 6.0 ± 1.5 per cent, the plasma AOC was increased by FRAP 8.3 ± 3.3 per cent and by ABTS 6.0 ± 2.0 per cent and no significant variation of plasma protein or plasma uric acid was found.
Practical implications
Maté polyphenols has a thrifty effect on the natural antioxidant defenses of the body, which are beneficial to human health.
Originality/value
There was no information on the bioavailability of polyphenols in YM infusions prepared in its traditional form as “hot mate”.
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This chapter draws upon the ongoing gaps and injustices in Western water policy and law, exploring its paucity in recognition of Indigenous Water rights. Exacerbated by National…
Abstract
This chapter draws upon the ongoing gaps and injustices in Western water policy and law, exploring its paucity in recognition of Indigenous Water rights. Exacerbated by National Water legislation and ongoing colonial racism, notions of ‘ownership’ of water resources that are licenced through the Crown represent a site where a paradigm shift is needed to dismiss the myth of aqua nullius and secure Aboriginal Water rights (Marshall, 2017). The Gunditjmara success in obtaining United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage listing of the Budj Bim eel traps and the Yarra River (Wilip-gin Birrarung murron) Protection Act (2017) are two examples that illustrate recognition of Aboriginal connections to water, but at the same time reveal weaknesses in Australian water policy. Sustainable Indigenous culture requires legal, social and cultural recognition and enactment of Aboriginal Water rights.
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Chih-Hui Shieh, I-Ling Ling and Yi-Fen Liu
As a smart service, location-based advertising (LBA) integrates advanced technologies to deliver personalized messages based on a user’s real-time geographic location and needs…
Abstract
Purpose
As a smart service, location-based advertising (LBA) integrates advanced technologies to deliver personalized messages based on a user’s real-time geographic location and needs. However, research has shown that privacy concerns threaten the diffusion of LBA. This research investigates how privacy-related factors (i.e. LBA type, privacy self-efficacy (PSE) and consumer generation) impact consumers’ value-in-use and their intention to use LBA.
Design/methodology/approach
This study developed and examined an LBA value-in-use framework that integrates the role of LBA type, consumers’ PSE and consumer generation into the technology acceptance model (TAM). Data were collected through two experiments in the field with a total of 374 consumers. The proposed relationships were tested using PROCESS modeling.
Findings
The results reveal that pull (vs push) LBA causes higher value-in-use in terms of perceived usefulness and perceived ease of use, leading to greater usage intention. Further, the differences in the mediated relationship between pull- and push-LBA are larger among consumers of low PSE (vs high PSE) and Generation Z (vs other generations). The findings suggest that the consumer value-in-use brought about by LBA diminishes when using push-LBA for low PSE and Generation Z consumers.
Originality/value
This research is the first to integrate the privacy-related interactions of LBA type and consumer characteristics into TAM to develop a TAM-based LBA value-in-use framework. This study contributes to the literature on service value-in-use, smart services and LBA by clarifying the boundary conditions that determine the effectiveness of LBA in enhancing consumers’ value-in-use.
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Melanie Sauerland, Svenja Mehlkopf, Alana C Krix and Anna Sagana
– The purpose of this paper is to test how modifying one’s alibi statement interacts with exposure to deceptive interrogation techniques.
Abstract
Purpose
The purpose of this paper is to test how modifying one’s alibi statement interacts with exposure to deceptive interrogation techniques.
Design/methodology/approach
In all, 90 participants walked about a university building for 15 minutes and either stole an envelope from a staff pigeonhole (guilty condition) or put the envelope there along the way (innocent condition). Subsequently, participants were asked to provide an alibi for the past 15 minutes. Guilty and half of the innocent participants were instructed to omit that they had been in the vicinity of the pigeonholes. The rest of the innocent participants were asked to tell the truth. Several days later, participants were questioned about six statements taken from their alibis, three of which contained altered information.
Findings
As expected, participants were largely blind to our alterations, with detection rates ranging from 1 to 36 percent. Contrary to cognitive load predictions, detection rates did not vary as a function of truthfulness. Rather, guilty participants were less likely to detect alterations than innocents.
Research limitations/implications
Memory distrust and guilty suspects’ aim to keep a low profile might be possible explanations for these findings.
Practical implications
It is recommended that law enforcement officers and other legal practitioners refrain from using deceptive interrogation techniques and such techniques that can cause inconsistencies in suspects’ reports. Researcher should make it their task to educate these professional groups about the natural occurrence of memory related, non-deceptive inconsistencies in successive statements.
Originality/value
This research uses a new methodology to study the effect of deceptive interrogation techniques on both innocent and guilty suspects. The findings are relevant for legal practitioners and researchers.
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Deborah Agostino, Michela Arnaboldi and Martina Dal Molin
Public networks studies have widely diffused in recent years, but scant attention has been devoted to network change. By endorsing the notion of critical crossroads to describe a…
Abstract
Purpose
Public networks studies have widely diffused in recent years, but scant attention has been devoted to network change. By endorsing the notion of critical crossroads to describe a crucial turning point for the network survival, the purpose of this paper is to investigate how and why a goal-directed network changes, considering both the benefits and the constraints of the change.
Design/methodology/approach
This study adopts a longitudinal case study based upon an interventionist research approach (Jönsson and Lukka, 2006), with the researchers being immersed in the network life of a group of Italian public universities over a period of 17 years.
Findings
This paper proposes an empirical derived framework about network evolution that identifies two different types of crossroads (i.e. resource-driven crossroads and management driven) as drivers for network evolution. The main determinant behind these crisis situation were found in the heterogeneity of the network actors and, while overcoming the crossroads, informal sub-networks were found emerging.
Originality/value
This study enlarges current public network literature by focusing specifically on how and why networks change, an aspect underinvestigated by current literature.