325 research outputs found
Should Representation Elections Be Governed by Principles or Expediency?
Should the National Labor Relations Board\u27 set aside representation elections because one or more parties has tried to influence the voting with misrepresentation of facts or law? Although the Board is responsible for ensuring fair elections, in Midland National Life Insurance Co. it embraced a rule inconsistent with this statutory responsibility, rejecting the Hollywood Ceramics Co. rule and narrowly limiting Board review of campaign misrepresentations. This Article examines the Midland standard in light of the Board\u27s statutory duty to protect the right of employees to a free and fair choice of collective bargaining representatives. The Article reviews the historical development of the Board\u27s approach to the regulation of election campaign misrepresentations, criticizes the Board\u27s abnegation of its duty to ensure an employee\u27s free choice by its adoption of the Midland rule, and suggests a more flexible standard to be used in the review of campaign misrepresentations that would protect the rights of employees without involving the Board in the minutiae of representative election campaigning
The occurrence of faults in the Bunter Sandstone Formation of the UK Sector of the Southern North Sea and the potential impact on storage capacity
The Triassic Bunter Sandstone Formation of the Southern North Sea is believed to have significant potential to store CO2 for climate change mitigation [1]. It has fair to good reservoir properties and a seal is provided by the mudstones of the Triassic Haisborough Group. It has been folded into domes and periclines (henceforth Bunter domes) by the post depositional late Triassic to Tertiary movement of the underlying evaporites of the Zechstein Group. These domes have been identified as targets for CO2 storage as they are very large and at least some of them have the ability to retain buoyant fluids, demonstrated by the presence of gas fields in some domes [2], [3], [4], [5] (though the majority of the formation is saline water-bearing). However, faults have been identified within the Haisborough Group cap rock directly above a number of the Bunter domes. The faults are thought to have formed as result of extensional stresses exerted during dome formation. They may have an impact on storage site security, as they could act as migration pathways for CO2 out of the storage site and therefore limit the number of Bunter domes that could be utilised for storage of CO2. This study considers the occurrence of faults in the cap rock above the Bunter domes and the potential impact on static capacity estimates
Deformation induced disordered nanocristalline FeAl studied by advanced transmission electron microscopy methods
Nanokristalline intermetallische Werkstoffe stoßen aufgrund ihrer oft unerwarteten Eigenschaften auf zunehmendes wissenschaftliches Interesse. In der vorliegenden Arbeit wurde nanokristallines intermetallisches FeAl durch Verformung der B2 geordneten Fe-45at.%Al Legierung mittels Hochdrucktorsion hergestellt. Die resultierende Struktur besteht aus nanoskaligen Körnern mit hohen Versetzungsdichten und unregelmäßigen Korngrenzen. Für die detaillierte Charakterisierung wurden Beugungsmodus und Abbildungsmodus im Transmissionelektronenmikroskop kombiniert. Die komplexen Bildkontraste der verformungsinduzierten Nanokörner erfordern die Entwicklung neuer Analysemethoden. Hier wird eine Methode für Profilanalyse aus Feinbereichsbeugungsbildern (PASAD) vorgestellt, die lokal aufgelöste quantitative Analyse von Nanomaterialien erlaubt. PASAD wird erfolgreich auf nanokristalline Strukturen angewendet, die sich bei der Verformung von FeAl ausbilden. Es zeigt sich das unerwartete Resultat, dass sich die Größe der kohärenten Streuvolumina (CSD) mit zunehmendem Verformungsgrad nicht ändert. Durch Anwendung von PASAD auf eine Kippserie von Beugungsbildern wird eine Methode entwickelt, die erlaubt die mittlere Größe und Form der CSD in 3D zu bestimmen. Es zeigt sich, dass die CSD in der Torsionsebene elongiert sind. Es wurde in der Literatur berichtet, dass Verformung die Ordnung in FeAl zerstört. Im Gegensatz dazu wird in der vorliegenden Arbeit gezeigt, dass die Entordnung nicht vollständig ist, da nach der Verformung chemisch geordnete Nanodomänen vorhanden sind (ca. 2 nm). Eine thermische Behandlung führt zu Ordnungseinstellung, Erholung sowie der Neuordnung der Korngrenzen. Um diese Prozesse genauer zu untersuchen, werden die Größe der Ordnungsdomänen, die Größe der CSD und die Korngröße beim Aufheizen gemessen. Durch die thermische Behandlung reduziert sich die Korngröße um einen Faktor 2, wobei gleichzeitig die Größe der CSD um einen Faktor 2 und die Größe der Ordnungsdomänen um einen Faktor 15 anwachsen. Basierend auf der Vergröberung der Ordnungsdomänen wird ein Modell für die Ordnungseinstellung entwickelt und an die Resultate von dynamischer Differenzkalorimetrie angepasst. Das Modell erlaubt die Bestimmung der Leerstellendichte, der Leerstellen-Wanderungsenthalpie und des Leerstellen-Wanderungsvolumens. Durch gezieltes Ausheilen von Proben, die mittels Hochdrucktorsion verformt wurden, ohne zu entlasten, wird die Leerstellendichte bestimmt und mit jener nach Entlastung verglichen. Dabei wird eine Reduktion der Leerstellendichte beim Entlasten bestätigt.Bulk nanocrystalline intermetallic materials receive increasing scientific interest since they often show novel properties. In the present work intermetallic FeAl was made nanocrystalline by high pressure torsion deformation of a B2 ordered Fe-45at.%Al alloy. The resulting structures consist of nanoscaled grains with high defect densities and highly irregular grain boundaries. For their detailed characterization transmission electron microscopy studies combining imaging and diffraction are used. The complex image contrasts of deformation induced nanograins necessitate the development of new analysis techniques. A method yielding profile analysis from selected area electron diffraction patterns (PASAD) is worked out allowing a quantitative analysis of nanomaterials on a local scale. PASAD is applied successfully to analyse small nanocrystalline regions that are formed in FeAl during deformation showing the unexpected result that the coherently scattering domain (CSD) size is not changing as a function of strain. By applying PASAD to tilt series of diffraction patterns, a new method is derived that allows the determination of the average size and morphology of the CSD in 3D. It is shown that the average CSD is elongated in the shear plane. It was reported in the literature that in FeAl the long-range order is lost during deformation. In contrast, the present work shows that the disorder is not complete since it is revealed that chemically ordered nanodomains of about 2 nm are observed after deformation. Thermal annealing leads to the recurrence of the order, the recovery of dislocations and the rearrangement of grain boundaries. To study these processes, the ordered domain size, the CSD size and the grain size are monitored during annealing. The analysis yields the surprising result that during annealing the grain size is reduced by a factor of 2, while the CSD size increases by a factor of 2 and the ordered domain size by a factor of 15. Based on the coarsening of the chemically ordered nanodomains a model for the reordering process is developed and fitted to the results from differential scanning calorimetry. The model allows to determine the vacancy concentration, the vacancy migration enthalpy and the vacancy migration volume. Finally, by annealing of specimens deformed by high pressure torsion without unloading, i.e. maintaining the hydrostatic pressure, the vacancy concentration is determined and compared to that after unloading, thus confirming the occurrence of vacancy relaxation during unloading
Ordnungseinstellungen in nanokristallinem FeAl untersucht mit Transmissionselektronenmikroskopie und dynamischer Differenzkalorimetrie
Aus geordneten Fe-45at%Al-Einkristallen wurde durch Hochdruck-Torsions-Verformung nanokristallines entordnetes FeAl hergestellt. Die Rückkehr der chemischen Ordnung nach Temperaturbehandlung wurde systematisch mit Transmissionselektronenmikroskpie sowie dynamischer Differenzkalorimetrie untersucht. Mittels Modellierung der Ordnungseinstellung wurde das Kalorimetriesignal erfolgreich simuliert. Aus der Anpassung der modellierten Kurve an die experimentelle Kurve war es möglich wichtige physikalische Parameter wie die Leerstellenwanderungsenthalpie und die Leerstellenkonzentration von FeAl zu ermitteln. Die ermittelten Parameter stimmen gut mit Werten aus der Literatur überein. Die Leerstellenkonzentration ist für nanokristalline Materialien die durch Hochverformung hergestellt wurden sehr hoch und ist daher experimentell nur schwer zugänglich. Die in dieser Arbeit vorgestellte Methode, Parameter mittels Anpassung an ein Kalorimetriesignal zu bestimmen, stellt sich daher als sehr vielversprechend heraus
Thomas Sanders, Ernest Tucker, Gary Hamburg, eds., The Russian-Muslim confrontation in the Caucasus
This is a most extraordinary book at least on two counts. First, academics in the humanities, unlike their colleagues in sciences and medicine, are usually known to be staunch individualists who are extremely shy of cooperating, not to say of sharing information and ideas, with others. This book is a rare exception, being the result of such collaboration. Second, it contains not one but two narratives – translations of sources from the two sides of a conflict – in “an experiment in listening ..
Thomas Sanders, Ernest Tucker, Gary Hamburg, eds., The Russian-Muslim confrontation in the Caucasus
This is a most extraordinary book at least on two counts. First, academics in the humanities, unlike their colleagues in sciences and medicine, are usually known to be staunch individualists who are extremely shy of cooperating, not to say of sharing information and ideas, with others. This book is a rare exception, being the result of such collaboration. Second, it contains not one but two narratives – translations of sources from the two sides of a conflict – in “an experiment in listening ..
Comment se débarrasser d’un échec
RésuméL’article présente une lettre inédite du prince Mihail Semenovič Voroncov au maréchal Auguste-Frédéric-Louis Viesse de Marmont dans laquelle Voroncov apporte sa version personnelle de la campagne qu’il a menée en 1845 dans le Caucase, campagne connue dans l’historiographie russe comme l’« expédition de Dargo » (darginskaja ekspedicija). Après l’énorme échec que fut cette expédition, le prince se trouvait dans une position très difficile : tandis qu’officiellement la campagne était célébrée comme une victoire, officieusement les autorités russes imputaient à Voroncov la responsabilité de la défaite. Dans l’incapacité de faire connaître sa propre version des événements, le prince le fit dans cette lettre à un ami.AbstractHow to disengage oneself from a defeat : A letter from Prince Vorontsov to Maréchal Marmont.This article presents a hithereto unpublished letter from Prince Mikhail Semenovich Vorontsov to Maréchal Auguste-Frédéric-Louis Wiesse de Marmont which brings Vorontsov’s personal version of what happened in his campaign of 1845 in the Caucasus, known in Russian historiography as the “Dargo Expedition” (darginskaia ekspeditsiia). Following the colossal failure of this expedition Vorontsov found himself in an impossible position : While officially the expedition was celebrated as a success, unofficially the Russian authorities put the responsibility for the defeat on Vorontsov. Unable to voice his own version, the prince did so in this letter to a friend
Size effect in polymer-supported ultrathin metallic glass films
Although metallic glasses (MGs) exhibit a unique combination of mechanical and chemical properties, their application as structural or functional materials is hindered by the lack of ductility which leads to catastrophic brittle-like fracture. When the size of a MG sample is reduced below some critical value, typically of the order of a few hundred nanometers, then considerable ductility can be observed. However, this size effect was demonstrated so far mostly by nanomechanical testing inside a transmission electron microscope using samples prepared by focused ion beam (FIB) milling. Whether the ductile-like behavior of submicrometer-sized metallic glasses is a real “intrinsic” size effect or it is rather caused by extrinsic factors like sample shape, ion beam effect or parameters of the testing setup is currently a subject of extensive discussions in the community.
In this contribution the tensile properties of thin film Pd82Si18 MGs grown by sputter deposition on a polymer substrate are considered. The integrity of the MG films during stretching was monitored by in-situ measurements of the electrical resistance. An overview of electro-mechanical behavior of considered films is demonstrated in Fig. 1.The 250, 100, and 60 nm thick films fail in a brittle manner at 2% strain through propagation of long cracks perpendicularly to the straining direction. The rapid crack propagation in these films results in rapid increase of in-situ resistance signal. The size effect on the deformation behavior appears when the film thickness drops below 15 nm. The 7 nm thick films with the same composition show a crack-free deformation up to a strain of 7%. Even at higher strains no brittle-like failure but rather short and isolated cracks are observed. Cyclic tensile loading revealed extreme fracture resistance of ultrathin amorphous films showing no cracks after 30000 stretching cycles with a strain amplitude of 3%. Since all tests are performed at ambient conditions on films deposited using an industrially scalable process, the demonstrated size effect can be directly utilized for applications, such as protective coatings, nanoelectromechanical devices or half-transparent conductive layers for flexible electronics.
Please click Additional Files below to see the full abstract
Direct observation of nanocrystal-induced enhancement of tensile ductility in a metallic glass composite
Bulk metallic glasses (BMGs) have attracted wide interest, but their successful application is hindered by their low ductility at room temperature. Therefore, the use of composites of a BMG matrix with crystalline secondary phases has been proposed to overcome this drawback. In the present work we demonstrate the fabrication of a tailored BMG nanocomposite containing a high density of monodisperse nanocrystals with a size of around 20 nm using a combination of mechanical and thermal treatment of Cu36Zr48Al8Ag8 well below the crystallization temperature. Direct observations of the interaction of the nanocrystals with a shear band during in situ deformation in a transmission electron microscope demonstrate that the achieved nanocomposite has the potential to inhibit catastrophic fracture in tension. This demonstrates that a sufficient number of nanoscale structural heterogeneities can be a route towards BMG composites with superior mechanical properties
High pressure torsion of nickel powders obtained by electrodeposition
A new synthesis route for the production of bulk nanostructured materials is presented.
Fine Ni powder was made by selected appropriate electrolysis conditions. A
compact material with an average grain size below 40 nm was obtained by subsequent
cold pressing. Then, using the high pressure torsion (HPT) deformation technique dense
bulk nanocrystalline Ni was achieved. The detailed structural investigations of the asprepared
and HPT deformed Ni powder, including X-ray diffraction (XRD) and transmission
electron microscopy (TEM), reveal in both cases the presence of a face centered
cubic (FCC) phase without presence of any oxides. Coherently scattering domain size
measurements by XRD show a value of 24 nm for the as-deposited powder and an even
smaller value of 13.5 nm after HPT deformation. In addition, optical emission spectroscopy
was employed to determine the impurity content of the obtained nanostructured
material, showing a relatively low content of 0.9 % carbon and oxygen. The microhardness
increased after deformation from (1.5 ± 0.08) GPa for the as-deposited Ni powder
to (6.6 ± 0.2) GPa for the HPT deformed Ni powder.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2061
- …