Microstructural effects on the mechanical properties of carburized low-alloy steels

This study examined the effects of composition and initial microstructure on the physical, metallurgical, and mechanical properties of carburized SAE 8620 and PS-18 steels. Testing was performed on 8620 and PS-18 steels in the as-received and normalized conditions. Hardenability testing was conducted prior to additional heat treatments. Size and shape distortion, residual stress, retained austenite, and effective case depth measurements were obtained for specimens subjected to a carburizing heat treatment. Specimens subjected to a core thermal cycle heat treatment were tested to determine the tensile and Charpy impact properties of the core material of carburized components. Despite differences between the as-received and normalized materials prior to carburizing, testing revealed that normalizing did not have a significant effect on the properties of the carburized or core thermal cycle heat treated materials. PS-18 had a higher hardenability, effective case depth, and ultimate tensile strength and a lowerCharpy impact toughness than 8620

One-operator two-machine flow shop scheduling with setup times for machines and total completion time objective

In a manufacturing environment, when a worker or a machine switches from one type of operation to another, a setup time may be required. I propose a scheduling model with one operator and two machines. In this problem, a single operator completes a set of jobs requiring operations in a two-machine flow shop. The operator can perform only one operation at a time. When one machine is in use, the other is idle. Whenever the operator changes machine, a setup time is required. We consider the objective of total completion time. I formulate the problem as a linear integer programming with \u27 O\u27(\u27n\u273) 0-1 variables and \u27 O\u27(\u27n\u272) constraints. I also introduce some classes of valid inequalities. To obtain the exact solutions, Branch-and-Bound, Cut-and-Branch, Branch-and-Cut algorithms are used. For larger size problems, some heuristic procedures are proposed and the computational results are compared

Using sensor ontologies to create reasoning-ready sensor data for real-time hazard monitoring in a spatial decision support system

In order to protect at-risk communities and critical infrastructure, hazard managers use sensor networks to monitor the landscapes and phenomena associated with potential hazards. This strategy can produce large amounts of data, but when investigating an often unstructured problem such as hazard detection it can be beneficial to apply automated analysis routines and artificial intelligence techniques such as reasoning. Current sensor web infrastructure, however, is not designed to support this information-centric monitoring perspective. A generalized methodology to transform typical sensor data representations into a form that enables these analysis techniques has been created and is demonstrated through an implementation that bridges geospatial standards for sensor data and descriptions with an ontology-based monitoring environment. An ontology that describes sensors and measurements so they may be understood by an SDSS has also been developed. These tools have been integrated into a monitoring environment, allowing the hazard manager to thoroughly investigate potential hazards

e-PARTICIPATORY COMMUNITY BASED APPROACH ON LANDSLIDE PREPAREDNESS AND MITIGATION

IImu pengetahuan merupakan indikator penting dalam menentukan keberkesanan susun atur strategi bagi menangani kejadian tanah runtuh. Pengetahuan untuk mengenal pasti tanda-tanda awal tanah runtuh adalah perlu bagi mereka yang tinggal terutamanya di kawasan-kawasan berisiko tinggi. Knowledge is an important indicator in an effective landslide mitigation strategy. Knowledge has to be acquired by people living in high risk areas for landslide occurrence such that they will be able to identify early signs of landslides

Uptake of sensor data in emergency management

While disasters are becoming larger, more complex and more frequent, traditional emergency management response capacities are not increasing at the same rate. Sensor capabilities could fill this gap by providing improved situational awareness, or intelligence, for emergency managers. Data from sensors is increasing exponentially in quality and quantity while the cost of capturing and processing these data is decreasing. This creates immense opportunities to bring sensor data into emergency management practices. Unfortunately, not all sensors are created equal. The accuracy, precision, presentation and timeliness of data varies depending on the source, the way the product is structured and who produces it. It is therefore difficult for emergency managers to incorporate sensor data into decision making, particularly when they have not seen the data type before, and do not know where it originated, or how to use. This thesis researches how data product creators can tailor products to increase the likelihood of their product being incorporated in emergency management decision making. It focuses on the issue of data product uptake, which is inclusion of data products in decision making processes. This issue has been poorly covered in the existing literature. This thesis synthesises literature from a range of disciplines then designs and conducts three targeted studies to build upon this knowledge. The first study compares four international data systems which use the same data source but make different choices in the design of their products, this then provides examples of the impacts of these design choices. The second study looks at disaster inquiries in Australia to consider how sensor data has been used in decision making in the past, and what lessons have been learnt from these experiences. The third study surveys Australian emergency managers to collect their views on what products they use, trust and what factors lead to that trust. The results from these studies combine to create a comprehensive collection of design choices available to data product creators. This collection covers not just technical choices like accuracy, but also presentational and data policy choices, to create a more holistic picture of how creators can influence their products. The collection is then presented in a framework which, if applied throughout product development, would be expected to increase uptake of sensor data in emergency management decision making. Design choices and user-oriented design processes are emphasised as a crucially important yet poorly-examined aspect of data uptake in emergency management. This thesis finds that trust is key to whether emergency managers use a product or not, and that trust is created through a series of design choices which can be grouped into quality, reputation, maturity and data policy

The Art and Science of Data-Driven Journalism

Journalists have been using data in their stories for as long as the profession has existed. A revolution in computing in the 20th century created opportunities for data integration into investigations, as journalists began to bring technology into their work. In the 21st century, a revolution in connectivity is leading the media toward new horizons. The Internet, cloud computing, agile development, mobile devices, and open source software have transformed the practice of journalism, leading to the emergence of a new term: data journalism. Although journalists have been using data in their stories for as long as they have been engaged in reporting, data journalism is more than traditional journalism with more data. Decades after early pioneers successfully applied computer-assisted reporting and social science to investigative journalism, journalists are creating news apps and interactive features that help people understand data, explore it, and act upon the insights derived from it. New business models are emerging in which data is a raw material for profit, impact, and insight, co-created with an audience that was formerly reduced to passive consumption. Journalists around the world are grappling with the excitement and the challenge of telling compelling stories by harnessing the vast quantity of data that our increasingly networked lives, devices, businesses, and governments produce every day. While the potential of data journalism is immense, the pitfalls and challenges to its adoption throughout the media are similarly significant, from digital literacy to competition for scarce resources in newsrooms. Global threats to press freedom, digital security, and limited access to data create difficult working conditions for journalists in many countries. A combination of peer-to-peer learning, mentorship, online training, open data initiatives, and new programs at journalism schools rising to the challenge, however, offer reasons to be optimistic about more journalists learning to treat data as a source

2015, UMaine News Press Releases

This is a catalog of press releases put out by the University of Maine Division of Marketing and Communications between January 2, 2015 and December 31, 2015

Caractérisation des phases pré-et post-rupture d'éboulements rocheux de taille intermédiaire : Apport des enregistrements sismiques.

Mid-size rockfalls (10^3-10^5 m^3) represent a substantial hazard in mountainous areas, because of relative high rate of occurrence and destructive power. Consequently, few protection means can be applied, emphasizing the need for monitoring techniques and early warning prior to the collapse. After the rupture, quantitative information on therockfall propagation phase is scarce, owing to their suddenness and location in steep and rugged slopes. In this thesis work, an experimental approach is proposed to derive valuable information from seismic records during rockfall pre-rupture and post-rupture phases.The first part of this work aims at testing the applicability of the ambient vibration technique to monitor unstable rock compartments dynamic response during the pre-rupture phase. This technique {commonly employed in civil engineering for structural health monitoring{ reveals the resonant frequencies of a structure, a decrease in frequencyrevealing potential damage. A previous case study of an unstable limestone compartment brought to light a ~30% decrease in fundamental resonant frequency (f1) two weeks before the collapse, interpreted as a loss in contact stiffness with the adjacent rock mass.Following this innovative work, we selected and instrumented five prone-to-fall medium size rock compartments located in the Occidental Alps, showing various geological contexts (limestones, argillite and shale-sandstone series), deformation patterns and failure mechanisms. Ambient vibrations recorded on-site revealed characteristic seismic noise features. Spectral peaks were observed and attributed to resonant frequencies of the rock compartments, the fundamental resonant frequency (f1) showing clear polarization parallel to the line of maximum slope gradient and perpendicular to the main bounding fracture observed at most of the sites. Similar findings were made for an unstable rock compartment located in a volcanic caldera characterized by rapid morphological changes and intense rockfall activity. The dynamic response of the rear fracture network was explored, showing that spectralcontent of seismic noise is controlled by the caldera structure in the 0.5-5 Hz range. The direction of vibration is polarized perpendicularly to the fractures, while vibration amplitudes appear linked to compartment uncoupling from the rock massif. In this case, the physical origin of seismic noise amplification may be due to complex 2D or 3D resonance effects.For four alpine sites, the fundamental frequency f1 was monitored over more than one year and showed fluctuations clearly correlated with temperature oscillations. The thermal control over f1 is highly complex, showing both positive and negative correlations depending on site morphology and destructuration as well as on the studied oscillations periods (daily or seasonal). No change in fundamental frequency resulting from damage was observed over this time span. One site, characterized by intense rock fracturing and a deep-open rear fracture, showed high f1 sensitivity to temperature changes. Thermomechanical numerical simulations revealed that both material contraction-dilation and thermal dependency of the elastic modulus control f1 fluctuations. In addition, high amplitude seasonal f1 oscillations were explained by ice formation in the rear fracture. A criterion was developed to separate thermal-induced f1 fluctuations from damage effects, under the hypothesis that thermal sensitivity of a rock compartment increases towards failure.The second part of this work relates to the post-rupture phase of rockfalls. The seismic records generated by two mid-size rockfalls (one natural, one provoked) that occurred in the same place were analyzed, showing complex envelope and spectrogram features. Both events showed close magnitude, duration and spectral content. The seismic signals of the provoked event were calibrated using video shots, allowing estimation of fallen material velocity during the successive propagation phases. The seismic signal appeared mainly controlled by the propagation phase, two dominant seismic pulses being related to (1) the ground impact of fallen material after free-fall, and (2) the kinematics of one individual _10 m3 rock block. These two pulses are characterized by similar low frequency content but very different particle motions. The discrete element technique was tested to simulate the provoked rockfall propagation. The initial velocity field, the resolution of the topography model and contact laws parameterization were found of critical importance for matching the observed propagation characteristics.Les éboulements rocheux de volume intermédiaire (103-105 m3) posent un problème sérieux dans les régions montagneuses en raison de leur fréquence d'occurrence relativement élevée et de leur fort pouvoir destructeur. En conséquence, il est difficile de mener des travaux de protection pour réduire l'aléa, ce qui souligne le besoin de techniques de suivi et d'alerte précoce avant la rupture. Après l'éboulement, peu d'informations quantitatives sont disponibles sur la phase de propagation en raison de la soudaineté du phénomène et de sa localisation dans des pentes raides et difficiles d'accès. Dans ce travail de thèse, une approche expérimentale est proposée pour extraire des informations à partir d'enregistrements de signaux sismiques durant les phases pré- et post-rupture d'éboulements. La première partie de ce travail vise à tester la pertinence des vibrations ambiantes pour le suivi temporel de la réponse dynamique de compartiments rocheux lors de la phase pré-rupture. Cette technique -couramment employée en génie civil pour le suivi de l'intégrité des structures- permet d'extraire les fréquences de résonance d'une structure, dont la décroissance peut traduire l'endommagement. Une étude antérieure menée sur une colonne calcaire instable a montré une décroissance d'environ 30% de la fréquence fondamentale de résonance (f1) environ deux semaines avant la rupture, interprétée comme une diminution de la rigidité du contact avec le massif stable adjacent. Afin d'évaluer l'applicabilité de cette méthode dans d'autres contextes, cinq compartiments rocheux instables de volume intermédiaire ont été sélectionnés et instrumentés dans les Alpes occidentales dans des géologies variées (calcaires, pélites, alternance grès-schistes), pour différents mécanismes de déformation et de rupture (glissement en pied, basculement, glissement composé). Les vibrations ambiantes enregistrées sur les compartiments instables montrent des pics spectraux, contrairement aux massifs adjacents. Ces pics sont attribués aux fréquences de résonance des compartiments, dont la fréquence fondamentale (f1) montre une polarisation préférentielle perpendiculaire à la fracture arrière présente sur la plupart des sites.La réponse dynamique d'un compartiment instable situé sur le rebord d'une caldera volcanique (cratère Bory, Piton de la Fournaise, La Réunion) et relié à un réseau de fracturation arrière étendu a été investiguée. Sur le compartiment instable, les caractéristiques du bruit de fond (fréquence de résonance, polarisation) sont comparables avec celles observées sur les sites alpins. A l'intérieur du cratère, la structure et la fracturation contrôlent le contenu spectral du bruit de fond, dans la gamme de fréquences 0,5-5 Hz. La direction de vibration préférentielle est orientée perpendiculairement aux fractures et les amplitudes semblent liées au degré de découplage avec le massif rocheux. Dans ce cas d'étude, l'origine physique de la résonance observée au sein du cratère pourrait être due à des effets de résonance 2D ou 3D.Pour quatre sites d'étude, la fréquence fondamentale (f1) a été suivie sur une période supérieure à un an et montre des fluctuations corrélées avec les variations de température. Le contrôle de f1 par la température est complexe, des corrélations positives ou négatives pouvant être observées selon la morphologie du site, la déstructuration et la période d'étude (journalière ou saisonnière). En revanche, il n'a pas été observé de changement de fréquence fondamentale du à de l'endommagement. La plus forte sensibilité de f1 aux variations de température a été observée sur un compartiment caractérisé par une fracturation intense et séparé du massif par une fracture arrière subverticale largement ouverte. Dans ce cas, les simulations thermo-mécaniques montrent que la contraction-dilatation du matériau et la dépendance de son module élastique à la température permettent d'expliquer les fluctuations de f1. Lors des périodes hivernales, la très forte augmentation de f1 est due à la formation de glace dans la fracture arrière. Par la suite, un critère a été développé en vue discriminer les fluctuations de f1 d'origine thermique et celles induites par de l'endommagement, en faisant l'hypothèse que la sensibilité thermique d'un compartiment instable augmente vers la rupture.La seconde partie de ce travail a pour objectif d'étudier le lien entre la phase post-rupture des éboulements et les signaux sismiques générés. Pour cela, les enregistrements de deux éboulements de volume intermédiaire {un naturel, l'autre provoqué{ survenus au même lieu et à quelques mois d'intervalle ont été analysés. L'enveloppe des signauxsismiques montre une forme complexe avec des signaux émergents et des pulses d'énergie, tandis que le spectrogramme présente une forme triangulaire caractéristique de sources en mouvement et/ou de processus d'entraînement de matériau. Les éboulements naturel et provoqué ont une magnitude, une durée et un contenu spectral comparables. Les signaux sismiques de l'éboulement provoqué ont été calibrés à l'aide de vidéos, permettantd'estimer la vitesse de propagation. Le signal sismique apparait contrôlé principalement par la phase de propagation, les deux pulses dominant le signal étant liés à (1) l'impact de la masse sur le sol après la phase de chute libre et (2) la cinématique d'un bloc isolé de volume ~10 m3. Ces deux pulses sont caractérisés par des contenus spectraux similaires à basse fréquence, mais des polarisations du mouvement très différentes. La méthode des éléments discrets a été testée pour simuler la propagation de l'éboulement déclenché, montrant que le champ initial de vitesses, la résolution du modèle topographique et les paramètres des lois de contact sont les paramètres clés contrôlant le modèle de propagation

Federal Register

Daily publication of the U.S. Office of the Federal Register contains rules and regulations, proposed legislation and rule changes, and other notices, including "Presidential proclamations and Executive Orders, Federal agency documents having general applicability and legal effect, documents required to be published by act of Congress, and other Federal agency documents of public interest" (p. ii). Table of Contents starts on page iii