Search results for "void"
showing 10 items of 435 documents
Robotic path planning for non-destructive testing – A custom MATLAB toolbox approach
2016
AbstractThe requirement to increase inspection speeds for non-destructive testing (NDT) of composite aerospace parts is common to many manufacturers. The prevalence of complex curved surfaces in the industry provides motivation for the use of 6 axis robots in these inspections. The purpose of this paper is to present work undertaken for the development of a KUKA robot manipulator based automated NDT system. A new software solution is presented that enables flexible trajectory planning to be accomplished for the inspection of complex curved surfaces often encountered in engineering production. The techniques and issues associated with conventional manual inspection techniques and automated s…
Combinatorial Gray codes for classes of pattern avoiding permutations
2007
The past decade has seen a flurry of research into pattern avoiding permutations but little of it is concerned with their exhaustive generation. Many applications call for exhaustive generation of permutations subject to various constraints or imposing a particular generating order. In this paper we present generating algorithms and combinatorial Gray codes for several families of pattern avoiding permutations. Among the families under consideration are those counted by Catalan, Schr\"oder, Pell, even index Fibonacci numbers and the central binomial coefficients. Consequently, this provides Gray codes for $\s_n(\tau)$ for all $\tau\in \s_3$ and the obtained Gray codes have distances 4 and 5.
Changes in Stress, Coping Styles, and Life Satisfaction between the First and Second Waves of the COVID-19 Pandemic: A Longitudinal Cross-Lagged Stud…
2021
In this study, we aimed to explain the interplay mechanism between stress, life satisfaction, and coping styles among university students. A cohort study was performed during the first (wave 1; W1) and second (wave 2; W2) waves of the Coronavirus disease 2019 (COVID-19) pandemic. The total sample included 231 university students, of which 59.31% were women. The Satisfaction with Life Scale (SWLS), Perceived Stress Scale (PSS), and Coping Inventory for Stressful Situations (CISS) were included in one online survey. Stress, emotion-oriented, and avoidance-oriented coping styles increased from W1 to W2 of the COVID-19 pandemic, while life satisfaction and task-oriented coping decreased. The pa…
Developmental dynamics between children’s externalizing problems, task-avoidant behavior, and academic performance in early school years: A 4-year fo…
2015
This longitudinal study investigated the associations among children’s externalizing problems, task-avoidant behavior, and academic performance in early school years. The participants were 586 children (43% girls, 57% boys). Data pertaining to externalizing problems (teacher ratings) and task-avoidant behaviors (mother and teacher ratings) were gathered, and the children were tested yearly on their academic performance in Grades 1–4. The results were similar for both genders. The analyses supported a mediation model: high externalizing problems in Grades 1 and 2 were linked with low academic performance in Grades 3 and 4 through increases in task-avoidant behavior in Grades 2 and 3. The res…
How and When Do Leaders Influence Employees' Well-Being? Moderated Mediation Models for Job Demands and Resources
2019
Following the call of recent reviews on leadership and well-being, the purpose of this study is to examine how and when two contrasting leadership styles, transformational leadership (TFL) and passive-avoidant leadership (PAL), are related to employees’ anxiety and thereby either promote or inhibit employees’ well-being. Using the prominent job demands-resources (JD-R) model as a theoretical framework, we propose that the relationship between leadership behavior and anxiety is mediated by organizational job demands, namely, role ambiguity (RA), and job resources, namely, team climate for learning (TCL), as well as moderated by autonomy as important job characteristic. A sample of 501 knowle…
Using genetically-defined rodent strains for the identification of hippocampal traits relevant for two-way avoidance behavior: a non-invasive approach
1989
Genetically-defined rodent strains permit the identification of hippocampal traits which are of functional relevance for the performance of two-way avoidance behavior. This is exemplified here by analyzing the relationship between infrapyramidal mossy fibers (a tiny projection terminating upon the basal dendrites of hippocampal pyramidal neurons) and two-way avoidance learning in about 800 animals. The necessary steps include 1) identification of structural traits sensitive to selective breeding for extremes in two-way avoidance, 2) testing the robustness of the associations found by studying individual and genetical correlations between hippocampal traits and behavior, 3) establishing caus…
Effect of different mixing and placement methods on the quality of MTA apical plug in simulated apexification model
2017
Background It is necessary apical plug material to exhibit proper adaptation with the root canal walls. Presence of voids at the interface between the root canal wall and this material result in micro leakage, which might have a relationship with post treatment disease. The aim of the present study was to evaluate the effect of different mixing (manual and ultrasonic) and placement (manual and manual in association with indirect ultrasonic) method of Mineral Trioxide Aggregate (MTA) on the void count and dimension in the apical plug in natural teeth with simulated open apices. Material and methods Eighty human maxillary central incisors were selected. After simulation of the open apex model…
Influence of resin viscosity and vacuum level on mechanical performance of sandwich structures manufactured by vacuum bagging
2010
The choice of process parameters is critical in optimizing the mechanical properties of sandwich structures produced using the vacuum bagging technique. The aim of this paper is to analyze how the viscosity of the resin/curing agent system and the vacuum level influence the morphology and the mechanical behavior of sandwich beams with composite faces (epoxy resin and glass fiber fabric named COMBI 900) and a PVC foam core. Four different sandwich structures were produced by varying the viscosity of the epoxy resin/curing agent at constant maximum vacuum pressure. Three further structures were manufactured by varying the strength of the vacuum with the resin viscosity maintained constant at …
Il mutuo fondiario e la violazione del limite di importo massimo finanziabile: “scotismo” e onnipotenza delle etichette
2023
Il commento analizza una sentenza della Sezioni Unite e affronta il tema delle conseguenze civilistiche dell’erogazione di un mutuo fondiario in misura superiore rispetto al limite di importo massimo finanziabile, stabilito dalla Banca d’Italia in forza dell’art. 38, comma 2, T.U.B. La pronuncia si presenta di grande interesse perché correttamente esclude che il superamento di tale limite possa comportare la nullità del contratto di finanziamento, pervenendo a conclusioni in larga parte condivisibili tanto sui presupposti quanto sulle caratteristiche della nullità per violazione di norme imperative. Non altrettanto fondata si rivela, invece, l’ulteriore conclusione contraria al riconoscimen…
Avoiding patterns in irreducible permutations
2016
We explore the classical pattern avoidance question in the case of irreducible permutations, <i>i.e.</i>, those in which there is no index $i$ such that $\sigma (i+1) - \sigma (i)=1$. The problem is addressed completely in the case of avoiding one or two patterns of length three, and several well known sequences are encountered in the process, such as Catalan, Motzkin, Fibonacci, Tribonacci, Padovan and Binary numbers. Also, we present constructive bijections between the set of Motzkin paths of length $n-1$ and the sets of irreducible permutations of length $n$ (respectively fixed point free irreducible involutions of length $2n$) avoiding a pattern $\alpha$ for $\alpha \in \{13…