La cartographie de potentiel est couramment utilisée afin de détecter les zones de corrosion à risque dans les ouvrages en béton armé. Cette méthode utilise une électrode de référence positionnée à la surface du béton afin de mesurer la différence de potentiel entre un point à la surface du béton et une connexion au réseau d'armatures. Toutefois, il existe deux inconvénients majeurs à cette technique : la connexion au treillis d'armatures qui nécessite d'y avoir accès et la vérification de sa continuité électrique dans la zone de mesure. Dans le but de ne plus être soumis à ces inconvénients, une nouvelle méthode est proposée. Au lieu de se connecter au treillis, une seconde électrode de référence est utilisée, elle aussi positionnée à la surface du béton étudié. Cette configuration de mesure ne donne plus des potentiels électriques, mais des gradients de potentiel entre les deux électrodes de mesure. Par la mise en place de simulations numériques et d'essais expérimentaux, cette configuration de mesure est étudiée. En ce qui concerne le travail expérimental, deux dalles de béton armé de 3x3x0,15m ont été coulées afin d'être proche des conditions rencontrées sur site. Ensuite que des zones corrodées, dont la taille est contrôlée, sont créées de manière accélérée à l'aide d'un dispositif de migration de chlorures. L'épaisseur d'enrobage de la dalle ayant une influence sur les mesures, il a été choisi de couler deux dalles. La première dalle comporte un treillis dont l'épaisseur d'enrobage est constante alors que la seconde dalle possède une épaisseur d'enrobage variable. En ce qui concerne la modélisation, une étude paramétrique utilisant la méthode des éléments finis est réalisée. Cette modélisation permet l'étude de l'influence de nombreux paramètres tels que la résistivité, la taille de la zone corrodée, l'épaisseur d'enrobage, le procédé de mesure, etc. C'est l'analyse des courants d'échange, mais aussi des cartographies de potentiels et de gradients de potentiel qui permettent la corrélation entre les résultats expérimentaux et de simulation. C'est alors qu'il est possible de conclure sur la faisabilité de cette méthode et de ses avantages par comparaison avec la mesure classique. / Half-cell potential mapping is commonly used to detect corrosion risks in reinforced concrete structures. This method uses a reference electrode positioned on the surface of concrete for measuring potential difference by using a voltmeter connected to the reinforcement. However, there are two major drawbacks in the implementation of this method: the necessity to make an electrical connection to the reinforcement and the electrical continuity of this reinforcement. In order to overcome these disadvantages, a new method is proposed. Instead of using electrical connection to rebar, a second reference electrode is used, also positioned on the surface. These two electrodes configuration gives the electrical potential gradient on the concrete surface. By performing both experimental work and numerical modelling this method configuration is tested. For experimental work, two reinforced concrete slabs (3x3x0.15 meter sized) were cast to be close to actual structural conditions. The corroded areas are created with an accelerated method, using the migration of chloride ions. Corrosion size and localisation are controlled during the experiment. The thickness of the concrete cover has an influence on the measures, for this reason in the first slab reinforcement depth is fixed, while it is variable in the second slab. Concerning modelling, a parametric study using a finite element model is performed. This model allows the study of the influence of several parameters such as resistivity, corroded area size, concrete cover and also the measurement process. It is the analysis of the corrosion current, as well as potential mapping that allows the correlation between the experimental and modelling results. Discussion of both results concludes on the feasibility of this method and confirms its benefits compared to the usual half-cell potential mapping.

The selfie has become the currency of today; boldly stating: I was here, this is how I felt, and, most importantly, I exist. This has become our self-reflection. Exploring the self-portrait, as have countless artists of the past, Johnny Shield uses the various selfies as reference for his sculptural works - both empty vessels and sculptural busts. Made from glass these fragile objects are all doomed to break. You, the viewer, are witnessing a truly damned object: the central portrait uneasily rests on a pedestal that is actively electrolytically corroding. While on display, this pedestal will lean more and more precariously, ultimately spilling the glass portrait onto the ground. By participating in the legacy of self-portraiture but producing a self-destructive object, Johnny is simultaneously endorsing and condemning the sacredness of the art object, the selfie, as well as the practice of glorifying the artist.

Toxic leaders are a serious problem, but shockingly, there is no standard detection tool that is both efficient and accurate. Compounding the problem are the various definitions and descriptions used to operationalize toxic leadership. This research sought to align the literature, offer a concise definition, and assess the domains indicative of toxic leadership through two conceptually compatible studies. Study 1 involved development of a toxic leader threat detection scale. Results using a variable-centered approach indicated that follower perceptions (n = 357) of leader empathy (4-item scale; α = .93) and the need for achievement recognition (4-item scale; α = .83) significantly predicted the egoistic dominance behaviors (5-item scale; α = .93) employed by toxic leaders (R2 = .647, p < .001). Using a person-centered approach, the scale scores also revealed latent clusters of distinct behavioral patterns, representing significantly different toxic leader threat levels (low, medium, and high). Study 2 assessed whether followers (n = 357), without access to behavioral information, would infer toxic characteristics simply from a leader’s physical appearance. Participants perceived images of male leaders (η2 = .131) with masculine facial structures (η2 = .596) as most likely to behave aggressively, while feminine facial structures (η2 = .400) and female images (η2 = .104) created the highest perceptions of empathy. The subjects also selected male leaders with masculine faces (η2 = .044; η2 = .015) as more likely to desire recognition, but with an inverse relationship (η2 = .073) such that feminine looking males earned the lowest scores. Overall, these results supported the idea that empathy and the need for achievement recognition create an “ego gone wild” condition and, not only can we measure the behavioral tendencies of toxic leaders, but perhaps we can “see” them as well.

<p>Tidigare forskning pekar på att psykologiska faktorer påverkar hur individen rekryteras till en sekt. Förförståelsen inför denna intervjustudie var att det skulle kunna finnas ett behov av ett rehabiliteringscentrum i Sverige, och frågeställningen gällde vilka behov som föreligger hos en individ som lämnar en destruktiv sekt sett utifrån professionella hjälpares perspektiv. 14 personer deltog, psykiatriker, präster, politiker, terapeuter och psykologer. Resultatet visade att det finns olika anledningar till att individer rekryteras in i en sekt liksom till att de lämnar den. Resultatet visade också att det föreligger ett hjälpbehov hos individer som lämnar sekter och gemensamma svar för alla respondenter var att det behövs: (1) samtal, (2) gemenskap, (3) någon som lyssnar.</p>

<p>To be able to ensure quality, efficiency and safety in nuclear reactors, non-destructive evaluations (NDE) are performed. The moulding technique, which has been studied in this project, is an NDE method used to verify surface breaking cracks at various objects in reactor vessels.</p><p>The idea of moulding is to receive a copy of the replicated surface for microscopic analysis. Within forensic science the moulding technique is used at crime scenes to collect evidence and tie suspects to crimes. Underwater moulding, however, is a newly developed technique and WesDyne TRC is a pioneer in offering services within moulding for underwater purposes.</p><p>This project was initiated by WesDyne TRC to further their knowledge within the moulding technology. In the project, studies have been made at three important parameters effect on cast quality using three different polymer compounds. Problems during moulding, such as crack detection failures and bubbles in the casts, raise the question whether the underwater moulding technique can be trusted to detect cracks.</p><p>Results from the experiments led to a greater insight into the problem with receiving high quality casts during underwater moulding. Only if a satisfactory cast is made, the moulding method can be trusted to detect defects down to the detection target in both dry and wet environment.</p><p>To increase the surface quality of underwater casts a suggestion for mould design and a recommended moulding method was developed. In addition, one of the polymer compounds approved for use, turned out not to be suitable for underwater moulding.</p>

Tidigare forskning pekar på att psykologiska faktorer påverkar hur individen rekryteras till en sekt. Förförståelsen inför denna intervjustudie var att det skulle kunna finnas ett behov av ett rehabiliteringscentrum i Sverige, och frågeställningen gällde vilka behov som föreligger hos en individ som lämnar en destruktiv sekt sett utifrån professionella hjälpares perspektiv. 14 personer deltog, psykiatriker, präster, politiker, terapeuter och psykologer. Resultatet visade att det finns olika anledningar till att individer rekryteras in i en sekt liksom till att de lämnar den. Resultatet visade också att det föreligger ett hjälpbehov hos individer som lämnar sekter och gemensamma svar för alla respondenter var att det behövs: (1) samtal, (2) gemenskap, (3) någon som lyssnar.

The focus of this thesis is to derive analytical tools for the design of infrared nondestructive tests in single and multi layer material bodies. This requires the predetermination of the parameters of the experiment such that the infrared image has the required resolution for defect detection. Inverse heat conduction in single and multi-layer materials is investigated to determine the required frequency of excitation in order to obtain a desired temperature at the observation point. We use analytical quadrupole representation to derive a polynomial relation to estimate the frequency of the periodic excitation as a function of the temperature amplitude at a given observation point within the body. The formula includes characteristic geometric and material parameters of the system. The polynomial formula can be an e ective design tool for quick frequency predetermination in the design of non-destructive testing experiments with infrared thermography. The convergence and accuracy of the formula is assessed by comparison with the analytical thermal quadrupole solution and experimental results. We also investigate the e ect of the nite length of the material domain in order to establish the range of applicability of a simpli ed formula based on semi-in nite domain assumption. The e ect of nite length is investigated analytically by using (i) Fourier series which accounts for transients and (ii) Time varying solution associated to the steady state solution when a purely periodic excitation is applied. These results are also compared with numerical solution obtained with commercial nite element software ANSYSTM.

Time of Flight Diffraction (TOFD) is one of the most accurate ultrasonic methods for crack detection and sizing in pipeline girth welds. Its performance, however, is limited by the temporal resolution of the signal. In this thesis, we develop a signal processing method based on autoregressive spectral extrapolation to improve the temporal resolution of ultrasonic signals. The original method cannot be used in industrial applications since its performance is highly dependent on selection of a number of free parameters. This method is modified by optimizing its various steps and limiting the number of free parameters, and an automated algorithm for selection of values for the remaining free parameters is proposed based on the analysis of a large set of synthetic signals. The performance of the final algorithm is evaluated using experimental data; it is shown that the uncertainty in crack sizing accuracy can be reduced by as much as 80%. Furthermore, the proposed method is shown to be capable of resolving overlapping echoes; therefore, smaller cracks that have echoes that are not clearly resolved in the raw signal, can be detected and sized in the enhanced signal.

Time of Flight Diffraction (TOFD) is one of the most accurate ultrasonic methods for crack detection and sizing in pipeline girth welds. Its performance, however, is limited by the temporal resolution of the signal. In this thesis, we develop a signal processing method based on autoregressive spectral extrapolation to improve the temporal resolution of ultrasonic signals. The original method cannot be used in industrial applications since its performance is highly dependent on selection of a number of free parameters. This method is modified by optimizing its various steps and limiting the number of free parameters, and an automated algorithm for selection of values for the remaining free parameters is proposed based on the analysis of a large set of synthetic signals. The performance of the final algorithm is evaluated using experimental data; it is shown that the uncertainty in crack sizing accuracy can be reduced by as much as 80%. Furthermore, the proposed method is shown to be capable of resolving overlapping echoes; therefore, smaller cracks that have echoes that are not clearly resolved in the raw signal, can be detected and sized in the enhanced signal.

In certain industries, quality testing is crucial, to make sure that the components being manufactured do not contain any defects. One method to detect these defects is to heat the specimen being inspected and then to study the cooling process using infrared thermography. The explorations of non-destructive testing using thermography is at an early stage and therefore the purpose of this thesis is to analyse some of the existing techniques and to propose improvements. A test specimen containing several different defects was designed specifically for this thesis. A flash lamp was used to heat the specimen and a high-speed infrared camera was used to study both the spatial and temporal features of the cooling process. An algorithm was implemented to detect anomalies and different parameter settings were evaluated. The results show that the proposed method is successful at finding the searched for defects, and also outperforms one of the old methods.