A survey of instrumented indentation studies on metallic glasses

2004 ◽  
Vol 19 (1) ◽  
pp. 46-57 ◽  
Author(s):  
C.A. Schuh ◽  
T.G. Nieh
Keyword(s):  
Metallic Glasses ◽  
Structural Changes ◽  
Shear Banding ◽  
Depth Sensing ◽  
Future Directions ◽  
Fundamental Physics ◽  
New Approach ◽  
The Past ◽  
Rate Dependent

The development of instrumented nanoindentation equipment has occurred concurrently with the discovery of many new families of bulk metallic glass during the past decade. While indentation testing has long been used to assess the mechanical properties of metallic glasses, depth-sensing capabilities offer a new approach to study the fundamental physics behind glass deformation. This article is a succinct review of the research to date on the indentation of metallic glasses. In addition to standard hardness measurements, the onset of plasticity in metallic glasses is reviewed as well as the role of shear banding in indentation, structural changes beneath the indenter, and rate-dependent effects measured by nanoindentation. The article concludes with perspectives about the future directions for nanocontact studies on metallic glasses.

On Future Directions in Pathology

1982 ◽  
Vol 40 ◽  
pp. 274-277
Author(s):  
Benjamin F. Trump ◽  
Irene K. Berezesky ◽  
Raymond T. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clinical Pathology ◽  
Future Directions ◽  
Diagnostic Pathology ◽  
The Past ◽  
Transmission Electron ◽  
Organ Systems ◽  
The Many

The role of electron microscopy and associated techniques is assured in diagnostic pathology. At the present time, most of the progress has been made on tissues examined by transmission electron microscopy (TEM) and correlated with light microscopy (LM) and by cytochemistry using both plastic and paraffin-embedded materials. As mentioned elsewhere in this symposium, this has revolutionized many fields of pathology including diagnostic, anatomic and clinical pathology. It began with the kidney; however, it has now been extended to most other organ systems and to tumor diagnosis in general. The results of the past few years tend to indicate the future directions and needs of this expanding field. Now, in addition to routine EM, pathologists have access to the many newly developed methods and instruments mentioned below which should aid considerably not only in diagnostic pathology but in investigative pathology as well.

Reform in the Rail and Electricity sectors in Russia: Restructuring, Competition and the Ministry for Antimonopoly Policy

2003 ◽  
Vol 53 (4) ◽  
pp. 339-362 ◽  
Author(s):  
R. Pittman
Keyword(s):  
Russian Federation ◽  
Structural Changes ◽  
International Experience ◽  
State Ownership ◽  
The Past ◽  
The Russian Federation ◽  
The Government ◽  
And Control ◽  
Two Sectors

The Russian Federation is in the process of making major structural changes to its railway and electricity sectors. Both sectors will be at least partly vertically disintegrated, with the aim of creating competition in the “upstream” sector while maintaining state ownership and control of the monopoly “grid”. This paper examines the details of reform and restructuring in the context of the international experience with reform and restructuring in these two sectors, and considers the role of the Ministry for Antimonopoly Policy in reform, both in the past as an “advocate for competition” within the government, and in the future as the guarantor of non-discriminatory access to the grids by non-integrated upstream producers.

Women in the history of linguistics

2020 ◽  
pp. 1-30
Author(s):  
Wendy Ayres-Bennett ◽  
Helena Sanson
Keyword(s):  
Language Acquisition ◽  
Central Section ◽  
Future Directions ◽  
The Past ◽  
Early Stages ◽  
Challenges And Opportunities ◽  
History Of Linguistics ◽  
History Of ◽  
Role Of Women

This Introduction outlines the need for a ‘true history’ (Lerner 1976) of the role of women in the history of linguistics, which considers them on their own terms, and challenges categories and concepts devised for traditional male-dominated accounts. We start by considering what research has already been conducted in the field, before exploring some of the reasons for the relative dearth of studies. We outline some of the challenges and opportunities encountered by women who wished to study the nature of language and languages in the past. The geographical and chronological scope of this volume is then discussed. In a central section we examine some of the major recurring themes in the volume. These include attitudes towards women’s language, both positive and negative; women and language acquisition and teaching; and women as creators of new languages and scripts. We further explore women as authors, dedicatees, or intended readers of metalinguistic texts, as interpreters and translators, and as contributors to the linguistic documentation and maintenance. We consider how women supported male relatives and colleagues in their endeavours, sometimes in invisible ways, before reviewing the early stages of their entry into institutionalized contexts. The chapter concludes with a brief section on future directions for research.

scholarly journals Atomic-scale viscoplasticity mechanisms revealed in high ductility metallic glass films

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hosni Idrissi ◽  
Matteo Ghidelli ◽  
Armand Béché ◽  
Stuart Turner ◽  
Sébastien Gravier ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Metallic Glasses ◽  
Shear Banding ◽  
Atomic Scale ◽  
Microscopy Imaging ◽  
Rate Dependent ◽  
Imaging And Spectroscopy ◽  
Shear Transformation Zones ◽  
The Impact ◽  
Glass Films

Abstract The fundamental plasticity mechanisms in thin freestanding Zr65Ni35 metallic glass films are investigated in order to unravel the origin of an outstanding strength/ductility balance. The deformation process is homogenous until fracture with no evidence of catastrophic shear banding. The creep/relaxation behaviour of the films was characterized by on-chip tensile testing, revealing an activation volume in the range 100–200 Å3. Advanced high-resolution transmission electron microscopy imaging and spectroscopy exhibit a very fine glassy nanostructure with well-defined dense Ni-rich clusters embedded in Zr-rich clusters of lower atomic density and a ~2–3 nm characteristic length scale. Nanobeam electron diffraction analysis reveals that the accumulation of plastic deformation at room-temperature correlates with monotonously increasing disruption of the local atomic order. These results provide experimental evidences of the dynamics of shear transformation zones activation in metallic glasses. The impact of the nanoscale structural heterogeneities on the mechanical properties including the rate dependent behaviour is discussed, shedding new light on the governing plasticity mechanisms in metallic glasses with initially heterogeneous atomic arrangement.

scholarly journals The Asian Rice Sector at a Crossroads

2020 ◽  
Vol 65 (4) ◽  
Author(s):  
Samarendu Mohanty
Keyword(s):  
Structural Changes ◽  
Special Focus ◽  
Asian Countries ◽  
Recent Past ◽  
Nutrition Security ◽  
The Past ◽  
Asian Rice ◽  
Rice Area ◽  
Key Issues

This paper examined the trend in Asian rice production, role of rice in human nutrition and documents structure of rice market in major Asian Countries, by analyzing supply demand and trade scenarios for the fast five decades. Country wise data from FAOSTAT and WTO were collected for the past five decades, to analyze key issues related to rice sector with special focus on rice markets in Asia. Rice Area and production has been increased significantly at higher rate than the population growth rate in Asia over the past fifty years. This resulted in increase of per capita availability of rice and contributed significantly to nutrition security. However, there are wide imbalances in supply-demand across Asian countries. Thus rice trade has become a major global economic activity in the recent past. The structural changes in global rice markets are discussed in detail in the paper.

scholarly journals Simultaneous improvement of plasticity and strength of metallic glasses by tailoring residual stress: Role of stress gradient on shear banding

2021 ◽  
Vol 197 ◽  
pp. 109246
Author(s):  
Lei Zhao ◽  
Dongxue Han ◽  
Shuai Guan ◽  
Xianzheng Lu ◽  
Kangcheung Chan ◽  
...  
Keyword(s):  
Residual Stress ◽  
Metallic Glasses ◽  
Shear Banding ◽  
Stress Gradient

Fewer butterflies seen by community scientists across the warming and drying landscapes of the American West

Science ◽  
2021 ◽  
Vol 371 (6533) ◽  
pp. 1042-1045
Author(s):  
M. L. Forister ◽  
C. A. Halsch ◽  
C. C. Nice ◽  
J. A. Fordyce ◽  
T. E. Dilts ◽  
...  
Keyword(s):  
Climate Change ◽  
American West ◽  
Climate Change Impacts ◽  
Western United States ◽  
New Approach ◽  
The Past ◽  
Biotic Response ◽  
Insect Populations ◽  
Annual Reduction

Uncertainty remains regarding the role of anthropogenic climate change in declining insect populations, partly because our understanding of biotic response to climate is often complicated by habitat loss and degradation among other compounding stressors. We addressed this challenge by integrating expert and community scientist datasets that include decades of monitoring across more than 70 locations spanning the western United States. We found a 1.6% annual reduction in the number of individual butterflies observed over the past four decades, associated in particular with warming during fall months. The pervasive declines that we report advance our understanding of climate change impacts and suggest that a new approach is needed for butterfly conservation in the region, focused on suites of species with shared habitat or host associations.

Cabozantinib plus immunotherapy combinations in metastatic renal cell and urothelial carcinoma

2021 ◽  
pp. 00-00
Author(s):  
Luis Meza ◽  
Jasnoor Malhotra ◽  
Crystal Favorito ◽  
Sumanta K Pal
Keyword(s):  
Urothelial Carcinoma ◽  
Renal Cell ◽  
Progressive Disease ◽  
Treatment Options ◽  
Future Directions ◽  
The Past ◽  
Metastatic Urothelial Carcinoma ◽  
Novel Approaches

Treatment options for metastatic renal cell carcinoma (mRCC) and metastatic urothelial carcinoma (mUC) have increased dramatically over the past decade. However, even when novel approaches have proven to be effective as monotherapy, many patients still develop progressive disease, and different strategies are needed to increase clinical response and quality of life. Strategies combining targeted therapy (TT) and immunotherapy (IO) have emerged as a way to shorten the gap between responders and nonresponders to monotherapy and have reported promising results. In this review, we discuss the current role of cabozantinib in combination with IO agents in the treatment of metastatic RCC and UC and go over future directions in the field.

scholarly journals Nanoscale strength distribution in amorphous versus crystalline metals

2010 ◽  
Vol 25 (12) ◽  
pp. 2251-2263 ◽  
Author(s):  
C.E. Packard ◽  
O. Franke ◽  
E.R. Homer ◽  
C.A. Schuh
Keyword(s):  
Yield Point ◽  
Metallic Glasses ◽  
Structural Changes ◽  
Thermal Fluctuations ◽  
Strength Distribution ◽  
Future Research ◽  
Transformation Zone ◽  
Crystalline Materials ◽  
Plastic Yield

Low-load nanoindentation can be used to assess not only the plastic yield point, but the distribution of yield points in a material. This paper reviews measurements of the so-called nanoscale strength distribution (NSD) on two classes of materials: crystals and metallic glasses. In each case, the yield point has a significant spread (10–50% of the mean normalized stress), but the origins of the distribution are shown to be very different in the two materials classes. In crystalline materials the NSD can arise from thermal fluctuations and is attended by significant rate and temperature dependence. In metallic glasses well below their glass-transition temperature, the NSD is reflective of fluctuations in the sampled structure and is not very sensitive to rate or temperature. Computer simulations using shear transformation zone dynamics are used to separate the effects of thermal and structural fluctuations in metallic glasses, and support the latter as dominating the NSD of those materials at low temperatures. Finally, the role of the NSD as a window on structural changes due to annealing or prior deformation is discussed as a direction for future research on metallic glasses in particular.

scholarly journals New Insights Into the Role of Aberrant Hippocampal Neurogenesis in Epilepsy

2021 ◽  
Vol 12 ◽  
Author(s):  
Peng Chen ◽  
Fuchao Chen ◽  
Yue Wu ◽  
Benhong Zhou
Keyword(s):  
Molecular Mechanisms ◽  
Wide Spectrum ◽  
Hippocampal Neurogenesis ◽  
Adult Hippocampal Neurogenesis ◽  
Future Directions ◽  
The Past ◽  
The Central Nervous System ◽  
Spontaneous Recurrent Seizures ◽  
Patients With Epilepsy

Data accumulated over the past four decades have confirmed that adult hippocampal neurogenesis (HN) plays a key role in the wide spectrum of hippocampal pathology. Epilepsy is a disorder of the central nervous system characterized by spontaneous recurrent seizures. Although neurogenesis in persistent germinative zones is altered in the adult rodent models of epilepsy, the effects of seizure-induced neurogenesis in the epileptic brain, in terms of either a pathological or reparative role, are only beginning to be explored. In this review, we described the most recent advances in neurogenesis in epilepsy and outlooked future directions for neural stem cells (NSCs) and epilepsy-in-a-dish models. We proposed that it may help in refining the underlying molecular mechanisms of epilepsy and improving the therapies and precision medicine for patients with epilepsy.

Sign in / Sign up

Export Citation Format

Share Document