Mathematical model of welding parameters for rapid prototyping using robot welding

Rapid Prototyping is a relatively new technology that allows the creation of prototypes in a very short period of time compared with traditional manufacturing techniques. First, a model of the prototype is drawn, using a computer aided design program, which is then mathematically ‘sliced’ and used to build the prototype layer by layer, using material such as paper, resins, or thermoplastics, depending on the process. The main disadvantage of these processes is that they do not allow metal as a raw material. Rapid Prototyping using Robot welding is another approach that overcomes this problem by using a welding robot that deposits metal. As the success of the final component quality depends very much on the welding parameters, it is important to automate their calculation. To automate the task of determining the welding parameters and to generate welded components with consistent quality, a very simple mathematical algorithm was created. The tests carried out to gather the necessary information to generate this model, the mathematical model itself, the limitations of the equations, and the tests to check their feasibility are described. At the time the work was carried out, the authors were in the welding Engineering Groups, SIMS, Cranfield University, Cranfield, Beds. MK43 0SY, UK. Dr Ribeiro is now in the Department of Industrial Electronics, University of Minho, 4800 Guimarães, Portugal and Professor Norrish is in the Faculty of Engineering, University of Wollongong, Wollongong, NSW 2522, Australia. Manuscript received 12 May 1997; in final form 20 June 1997

Chewing gum moderates multi-task induced shifts in stress, mood, and alertness: A re-examination

The finding that chewing gum can moderate stress and mood changes following a multi-task cognitive stressor (Scholey, Haskell, Robertson, Kennedy, Milne, and Wetherell, 2009) was re-examined. In a repeated measures cross-over design, thirty participants completed a 20-minute multi-tasking stressor on consecutive days, both with and without chewing gum. Both prior to and post stressor, participants provided salivary cortisol samples and self-rated measures of stress, state anxiety, calmness, contentedness, and alertness. Contrary to Scholey et al. (2009), chewing gum failed to attenuate both salivary cortisol levels and the increase in self-rated stress. Self-rated anxiety, calmness, and contentedness were not impacted by chewing gum. This suggests that the stress effects reported by Scholey et al. may be constrained by particular features of that study (e.g. morning testing). However, consistent with Scholey et al. (2009), chewing gum was shown to increase alertness following the stressor. The mechanisms underpinning heightened alertness are unclear; however, such increases may be linked to greater cerebral activity following the chewing of gum (Fang Li, Lu, Gong, and Yew, 2005)

An Improved Implementation and Abstract Interface for Hybrid

Hybrid is a formal theory implemented in Isabelle/HOL that provides an interface for representing and reasoning about object languages using higher-order abstract syntax (HOAS). This interface is built around an HOAS variable-binding operator that is constructed definitionally from a de Bruijn index representation. In this paper we make a variety of improvements to Hybrid, culminating in an abstract interface that on one hand makes Hybrid a more mathematically satisfactory theory, and on the other hand has important practical benefits. We start with a modification of Hybrid's type of terms that better hides its implementation in terms of de Bruijn indices, by excluding at the type level terms with dangling indices. We present an improved set of definitions, and a series of new lemmas that provide a complete characterization of Hybrid's primitives in terms of properties stated at the HOAS level. Benefits of this new package include a new proof of adequacy and improvements to reasoning about object logics. Such proofs are carried out at the higher level with no involvement of the lower level de Bruijn syntax.Comment: In Proceedings LFMTP 2011, arXiv:1110.668

La relación personal en el tratamiento de la diversidad

El autor centra su aportación en diferentes características de los organismos vivos, para incorporarlas a las perspectivas interpretativas y operativas, y de los métodos actuales de intervención educativa. En el texto también se trata el enfoque positivo desde la dimensión técnica y no «voluntarista», teniendo en cuenta que los especialistas que adoptan la perspectiva del enfoque positivo dan mucha importancia al tema de la calidad de vida.L'autor centra la seva aportació en diferents característiques dels organismes vius, per incorporar- les a les perspectives interpretatives i operatives, i dels mètodes actuals d'intervenció educativa. Al text també es tracta l'enfocament positiu des de la seva dimensió tècnica i no «voluntarista», tenint en compte que els especialistes que adopten la perspectiva de l'enfocament positiu donen molta importància al tema de la qualitat de vida.The author focuses on the different characteristics of the alive organisms in order to include them into the interpretative and operative views of the current methods of educational intervention. He also deals with the positive focus, from the technical and «no voluntary» dimension, taking into account that those specialists having this kind of view do emphasize a lot on the quality of life issue

Cognitive facilitation following intentional odor exposure

This paper reviews evidence that, in addition to incidental olfactory pollutants, intentional odor delivery can impact cognitive operations both positively and negatively. Evidence for cognitive facilitation/interference is reviewed alongside four potential explanations for odor-induced effects. It is concluded that the pharmacological properties of odors can induce changes in cognition. However, these effects can be accentuated/attenuated by the shift in mood following odor exposure, expectancy of cognitive effects, and cues to behavior via the contextual association with the odor. It is proposed that greater consideration is required in the intentional utilization of odors within both industrial and private locations, since differential effects are observed for odors with positive hedonic qualities

Water activity in liquid food systems : A molecular scale interpretation

Water activity has historically been and continues to be recognised as a key concept in the area of food science. Despite its ubiquitous utilisation, it still appears as though there is confusion concerning its molecular basis, even within simple, single component solutions. Here, by close examination of the well-known Norrish equation and subsequent application of a rigorous statistical theory, we are able to shed light on such an origin. Our findings highlight the importance of solute-solute interactions thus questioning traditional, empirically based “free water” and “water structure” hypotheses. Conversely, they support the theory of “solute hydration and clustering” which advocates the interplay of solute-solute and solute-water interactions but crucially, they do so in a manner which is free of any estimations and approximations

A formalized general theory of syntax with bindings

We present the formalization of a theory of syntax with bindings that has been developed and refined over the last decade to support several large formalization efforts. Terms are defined for an arbitrary number of constructors of varying numbers of inputs, quotiented to alpha-equivalence and sorted according to a binding signature. The theory includes a rich collection of properties of the standard operators on terms, such as substitution and freshness. It also includes induction and recursion principles and support for semantic interpretation, all tailored for smooth interaction with the bindings and the standard operators

The diagnostic yield of cardiac screening in first-degree relatives of sudden arrhythmic death syndrome or unexplained cardiac arrest probands: A systematic review of the literature

Background: First-degree relatives of Sudden Arrhythmic Death Syndrome (SADS) or Unexplained Cardiac Arrest (UCA) are recommended to undergo clinical evaluation for potential inherited cardiac conditions (ICC). However, data on the yield of family screening in these populations remains scarce. Aim of review: This systematic review aimed to explore the diagnostic yield of clinical screening of first-degree relatives of SADS or UCA probands. A secondary aim was to compare the diagnostic yield of adult-aged and pediatric-aged relatives. Key scientific concepts of review: Included studies described the clinical cardiac screening and yield of first-degree relatives of SADS and UCA probands. Quality of selected studies was assessed using a modified Joanna Briggs Institute checklist. 14 studies met inclusion criteria for this review, together including 1646 first-degree relatives of SADS probands and 656 first-degree relatives of UCA probands. Overall diagnostic yield described ranged from 0 to 32 %. The combined mean diagnostic yield of SADS relatives did not differ significantly from that of relatives of UCA probands. Three studies described outcomes of clinical screening in pediatric relatives, with an overall reported yield of 9.4 % ± 3.4 %, not significantly different from adult populations. Whilst there is a clear indication for clinical screening of first-degree relatives following SADS or an UCA, a lack of well-designed large population-based studies means that the evidence base is not robust. The yield in reported literature varies considerably, with no difference between SADS and UCA cohorts and a similar yield in pediatric and adult relatives. This supports screening for all first-degree relatives regardless of age

How phyllosilicate mineral structure affects fault strength in Mg-rich fault systems

The clay mineralogy of fault gouges has important implications for the frictional properties of faults, often identified as a major factor contributing to profound fault weakness. This work compares the frictional strength of a group of Mg‐rich minerals common in the Mg‐Al‐Si‐O compositional space (talc, saponite, sepiolite, and palygorskite) by conducting triaxial frictional tests with water or argon as pore fluid. The studied minerals are chemically similar but differ in their crystallographic structure. Results show that fibrous Mg‐rich phyllosilicates are stronger than their planar equivalents. Frictional strength in this group of minerals is highly influenced by strength of the atomic bonds, continuity of water layers within the crystals, and interactions of mineral surfaces with water molecules, all of which are dictated by crystal structure. The formation and stability of the minerals studied are mainly controlled by small changes in pore fluid chemistry, which can lead to significant differences in fault strength