bluuebunny/crossref_metadata_2025 huggingface dataset:
Revealing the Strain-Hardening Mechanisms of Advanced High-Mn Steels by Multi-Scale Microstructure Characterization
Authors: Gutierrez-Urrutia Iván , Marceau Ross , Herbig Michael , Raabe Dierk
Published: May 2014

We have investigated the strain-hardening mechanisms across the relevant scales in a Fe-22Mn-0.6C (wt.%) twinning induced plasticity steel by multi-scale microstructure characterization. The approach makes use of electron microscopy techniques such as electron channeling contrast imaging (ECCI) to characterize microstructure features at the micro/nanoscale, and atomic-scale investigations of partitioning behavior across interfaces and solid solution/clustering effects by atom probe tomography (APT). The contribution of most relevant microstructure features to strain hardening is analyzed.
The Mechanical and Deformation Behavior of TWIP Steel Prepared by Directional Solidification
Authors: Wang Dan , wang kun , Shi Zi Mu , Han Fu Sheng
Published: May 2014

A directionally solidified TWIP steel (Fe-25Mn-2.5Al-2.5Si) was prepared by liquid metal cooling technology. The microstructure and mechanical behavior were examined and compared with usually solidified samples. The directionally solidified TWIP steel shows a typical columnar grain structure, and the maximum true stress and true strain along the longitudinal direction of the sample are 1060MPa and 71% respectively. As a comparison, the usually solidified samples shows an equiaxed grain microstructure with the maximum true stress and true strain of only 994MPa and 58%, respectively. Moreover, the two solidification modes also lead to very different strain hardening behavior, particularly in the changes of strain hardening rate with strain. This suggests that the grain boundary plays a key role in the mechanical properties of TWIP steels, and changing the grain boundaries can be effective to improve the comprehensive mechanical properties of TWIP steels.
Thermodynamic and Kinetic Calculation of Non-Equilibrium Microstructure Design of TRIP Steel
Authors: He Yan Lin , Zhu Na Qiong , Zheng Wei Sen , Lu Xiao Gang , Li Lin
Published: May 2014

The non-equilibrium microstructure of Fe-C-Mn-Si TRIP steel is designed bythermodynamic and kinetic calculation. The upper limit of bainitic transformation temperature iscalculated and compared to that characterized by CCT curve determination. s M temperature isdetermined based on thermodynamics of martensitic transformation and sublattice model. Thecalculation is conducted via TQ6-patch in Thermo-Calc software. Comparison between thecalculations and experiments reveals the relationship between non-equilibrium phase compositionand heat treatment parameters which can be utilized to achieve the elaborate design of alloy and heattreatment for super TRIP steel.
Surface Roughness and Friction in Hot Rolling of Stainless Steels
Authors: Jiang Zheng Yi , Wei Dong Bin , Cheng Xia Wei , Gao X. , Zhang J.W. , Huang Jun Xia , Zhang Ai Wen , Shi X. , Jiao S.H.
Published: May 2014

An experimental method was developed to examine oxidations of austenitic and martensitic stainless steels. The results show that the surface roughness along both rolling and transverse directions decreases with an increase of reduction. When the reheating time is increased, the average thickness of oxide scales of stainless steels increases, which results in relatively rough surface after hot rolling. The effects of oxide scale on the friction condition and surface roughness transfer in hot rolling depend on the oxide scale generated during reheating. The calculated surface roughness is close to the experimental results, which verifies the developed FEM model.
Semi-Solid Processing of Powder Steels in Cryogenically-Cooled Die
Authors: Masek Bohuslav , Aišman David , Rubešová Kateřina , Jirková Hana
Published: May 2014

By processing steels in the semi-solid state it is possible to achieve unconventional structures even with commonly used steels. This can be demonstrated on X210Cr12 tool steel. After semi-solid state processing, 96% of the microstructure can consist of metastable austenite. In the microstructure, there are polyhedral grains embedded in a ledeburitic network. A combination of semi-solid state processing and rapid solidification is a new method for modifying the microstructure more substantially. In the present experiment, two tool steels, CPM 15V and CPM S30V, were processed by an unconventional method. Since the steels are made by powder metallurgy, their initial structure contains globular carbides in ferritic matrix. Both materials have high levels of carbon and alloying elements, namely vanadium and chromium. The unconventional processing was carried out by mini-thixoforming which enables the use of a small amount of metal. After heating into the semi-solid region, the material was rapidly forced by lateral extrusion into a cavity of a metal die where rapid solidification and rapid cooling took place. Two cooling schedules were employed. In the first case, the die was at room temperature, whereas in the second one it was pre-cooled to-196°C using liquid nitrogen. Since the test sample was cooled from both sides and its thickness was 3 mm, immensely high cooling rates were achieved. The influence of the cooling rate was also noticeable in the microstructures containing high fractions of metastable austenite, martensite and carbides.
Effects of Austenite Conditioning and Transformation Temperature on the Bainitic Microstructure in Linepipe Steels
Authors: Regier R.W. , Reguly A. , Matlock David K. , Choi J.K. , Speer John G.
Published: May 2014

Low carbon bainitic steels are important in applications such as linepipe, and the details of the bainite microstructure control strength and toughness. The transformation of austenite to bainitic ferrite has been widely researched over the years, although recent use of electron backscatter diffraction techniques has provided opportunity to advance the characterization of various crystallographic aspects. In recent work, microstructures were characterized in a base steel containing 0.04 C and 1.7 Mn (wt. pct.) and two additional steels having modest carbon and manganese variations to influence the transformation behavior, with an interest in the MA (martensite-austenite) constituent and characteristics of the bainite developed at different transformation temperatures. Effects of austenite conditioning were also examined, as these steels contained an addition of 0.04 wt. pct. Nb. Microstructural details including crystallographic characteristics assessed using EBSD are presented, along with comments related to the implications of the results.
Optimization of Mechanical Properties of High Strength TRIP Steels
Authors: Li Lin , Gao Yi , He Yan Lin , Shi Wei , Zhang Mei , Lu Xiao Gang
Published: May 2014

Traditional TRIP steels have been developed for several decades, however, when thestrength reaches 1000MPa, the elongation rate is difficult to be raised over 20%. In the light ofthermodynamics, phase diagram of TRIP steel containing rather high amount of Al is optimized andthe attractive function of Al, which largely increases carbon solubility in austenite is found. As highercarbon content leads to higher stability of austenite and better TRIP effect of TRIP steel, newcomposition of high strength TRIP steel with high amount Al is designed as well as heat treatmentprocesses. The newly developed TRIP steel exhibits superior mechanical properties and the productof its strength and plasticity is higher than 30000 MPa%, i.e., the target of the mechanical propertiesof 3th generation automotive steel.
The Development and Application of High-Performance Ultra-High Strength Stainless Steel Subject to Marine Environment
Authors: Liu Zhen Bao , Liang Jian Xiong , Zhang Xiu Li , Yang Zhi Yong , Sun Guo Qiang
Published: May 2014

An alloy chemical composition of a new ultra-high strength stainless has been successfully designed through strengthening mechanisms of carbide and intermetallic compounds. The forging round bar with diameter of 200 mm has been manufactured by means of ultra-high purity smelting and the whole process technologies of micro-unit refinement and phase change control. It was revealed that the developed steel assumes tensile strength of 1960MPa, elongation of 13.5%, fracture toughness KIC greater than 90MPa·m1/2, and KISCC greater 60MPa·m1/2. Based on the microstructural observation and phase identification, it was found that the M2C and the Laves phase were precipitated in the martensitic laths and a small amount of austenite phase was retained in between the Martensitic lath interfaces, which were related to the improved strength and toughness of the developed steel. Furthermore, it was indicated that the steel also presents high fatigue properties and good high-temperature mechanical properties. The corrosion resistance of the steel is equivalent to that of 15-5PH stainless steel but much better than that of the Aermet100 steel under the condition of the marine atmosphere and sea water immersion. This developed steel can be applied in marine corrosive environment without the surface protection and thus can save the expensive maintenance costs and avoid environmental pollution. Based on the promising properties, it was concluded that the developed steel has wide application prospects in the fields of aviation, aerospace, ships, advanced machinery, and advanced machinery manufacturing and other high-tech.
Effect of Martensite Fraction on Void Nucleation Behavior and Ductility in DP Steels
Authors: Maeda Daisuke , Kawano Osamu
Published: May 2014

Void nucleation behavior of ferrite/martensite dual phase steels varying martensite fraction was investigated. As easily recognized, void fraction was increased with strain induced, and more voids were nucleated in the sample with higher martensite fraction. On the other hands, void fraction at ductile fracture was decreased with increasing martensite fraction. Void nucleation was observed to occur due to the fracture of martensite in DP steels. In the sample with high martensite fraction, many micro voids were nucleated at initial deformation with small strain and lead to ductile fracture. Inter-voids distance at the fracture was almost same among the DP steels with various martensite fractions. It is considered that the most effective factor on ductile fracture of DP steels was not 2nd phase fraction but the distance between 2nd phases which caused micro voids.
Temperature and Stress State Influence on Mechanical Properties and Damage Evolution of Dual-Phase Steels
Authors: Martinez Mayerling , Chottin Jerôme , Hug Eric
Published: May 2014

Dual Phase steels are increasingly selected for structural applications including parts in automotive industry because of their interesting mechanical properties and their good formability. This work presents an experimental analysis of the evolution of microstructure of a DP1000 alloy submitted to thermomechanical loadings. Monotonous tensile tests were performed at various plastic strain levels up to fracture for temperatures ranging between 25 °C and 440 °C. A strong degradation of the mechanical properties is observed for temperatures higher than 275 °C. The evolution with plastic strains and temperature of the microstructure was studied by scanning and transmission electron microscopy. Different microstructure parameters such as volume fraction of martensite and carbide precipitation were taken into account in order to understand the mechanical behavior of DP1000 steels tested in this temperature range. The microstructural observations indicate that diminution of carbon in martensite, due to its diffusion to form carbides, could partially explain the drop in mechanical properties at around 275 °C.
A Numerical Model for Predicting the Zener-Hollomon Parameter in the Friction Stir Processing of AZ31B
Authors: Ammouri Ali H. , Kheireddine Ali H. , Hamade Ramsey
Published: May 2014

Grain size determines to a large degree the mechanical properties of the friction stir processed (FSP) material. Developed in this work is a numerical (FEM) based-model for predicting values of the Zener-Hollomon parameter (Z-parameter) as function of input process parameters during friction stir processing of AZ31B. Prediction of Z values is desirable given that direct relations exist between the Z-parameter and the average grain size in the dynamically recrystallized zone (DRX). For this purpose, utilized in this work is a robust finite element model with a suitable constitutive equation and boundary conditions the results of which have been previously validated against published experimental data. A virtual test matrix constituting of 16 cases (4 spindle speed, N, x 4 feed, f) was run. Based on resulting state variables of strain rates and temperatures at a representative point within the stir zone, a statistically-validated power equation model was developed that relates Z-parameter values to input parameters of speed and feed. The results of the numerically developed power equation were validated against experimental results. This model can be readily used in future control frameworks to FSP produce AZ31B sheets of a predefined target grain size.
Assessment of Hydrogen Uptake and Permeation in AHSSs
Authors: Pang Xin , Fazeli Fateh , Attard Michael , Shi Chao
Published: May 2014

This study aims to develop novel experimental procedure that quantifies response of AHSSs with different microstructures, deformation status, and strength levels to hydrogen. The capacity for trapped hydrogen, kinetics of hydrogen absorption and loss, and hydrogen mobility are measured and analyzed by permeation tests. The experimental findings are discussed in terms of microstructural features for an interstitial free (IF) and a dual phase (DP) steels. Further, the density of trap sites and its effect on effective diffusivity of hydrogen in the steel are analyzed by means of a diffusion model.
Role of Microstructure in Susceptibility to Hydrogen Embrittlement of X70 Microalloyed Steel
Authors: Hejazi Daniel , Saleh Ahmed A. , Haq Ayesha , Dunne Druce , Calka Andrzej , Gazder Azdiar , Pereloma Elena V.
Published: May 2014

The effect of phases and steel processing on hydrogen uptake (diffusible and residual), surface and internal damage were evaluated using optical and scanning electron microscopy. The results have shown the fastest formation of blisters in ferrite-pearlite microstructure of strip, followed by equaixed ferrite-pearlite microstructure in normalised condition, then by ferrite-bainite microstructure. No blistering was observed in heat affected zone samples for up to 24 hrs charging. Analysis of hydrogen-induced cracking using electron back scattering diffraction has revealed that crack propagation has predominantly intragranular character without a clear preference on {001}, {110}, {112} and {123} planes and is independent of the steel microstructure and prior processing.
Complex Microstructural Banding of Continuously Cooled Carbide-Free Bainitic Steels
Authors: Morales-Rivas Lucia , Roelofs Hans , Hasler Stephan , Garcia-Mateo Carlos , Caballero Francisca G.
Published: May 2014

Chemical segregation of alloying elements during solidification of steel grades leads to development of a banded microstructure, causing a degree of anisotropy that can be detrimental to the mechanical behavior under service conditions. It is well-known that the presence of strongly orientated martensite bands in carbide-free bainitic microstructures, associated to inhomogeneous Mn redistribution during solidification, leads to a remarkable deterioration in toughness in advanced high strength bainitic steels. In this study, while bands were clearly visible on light optical micrographs of continuously cooled carbide-free bainitic steels, scanning electron microscopy examination revealed only a gradual transition between matrix and bands, both with a granular bainitic structure. Electron backscatter diffraction was used to quantify the bainitic packet size and volume fraction of martensite/austenite constituent between and within the bands, after a process of optimization of the analysis settings in order to minimize the inherent difficulties linked to sub-micrometric and minority phase indexation. The quantitative microstructural results showed negligible morphological differences between bainitic structure bands and matrix, only solute segregation of Cr and Mo was detected by energy-dispersive X-ray spectroscopy within bands, which must be responsible for a stronger resistance against metallographic etching in those regions.
Effects of Coarsening of Cementite in Pearlite before Austenitization on Formation of BWING and Mechanical Property in a Steel
Authors: Sakamoto Tatsuaki , Konishi Sanae , Nakanishi Yuta , Nakai Kiyomichi , Kobayashi Sengo
Published: May 2014

Effect of pre-treatment before austenitization on mechanical property in a steel has been investigated. Pre-treatment was done at 500°C for 600, 1200 and 1800s before austenitization at 1440°C for 120s. This pre-treatment was performed in order to introduce dislocation network into austenite, which acts as nucleation site for “bainite laths within austenite grain (BWING)”. BWING was formed with isothermal holding at 500°C for 10s after austenitization. Micro-Vickers hardness is measured in a steel with and without pre-treatment. The steel with appropriate pre-treatment exhibits high hardness, because large amounts of BWINGs are formed. In the case of cementites in pearlite being coarsened and the distance between cementites becoming large, dislocation network is apt to be introduced into γ. The dislocation network acts as nucleation site for BWING, resulting in the suppression of formation of intergranular bainite. BWINGs strengthen the steel.
L’espace public en partage. Expériences conflictuelles de l’espace et marginalisation
Authors: Margier Antonin
Published: May 2014

L’exclusion dans les espaces publics est souvent interprétée comme le résultat de politiques urbaines revanchistes visant à attirer touristes et classes supérieures aux dépens des personnes marginalisées. Autour de l’analyse d’usages conflictuels de l’espace public dans un quartier montréalais, cet article explore l’hypothèse selon laquelle l’exclusion prendrait aujourd’hui de nouvelles formes. Dans cette perspective, nous nous intéressons aux conditions de l’investissement des positions sociospatiales et aux diverses expériences de l’espace, afin de saisir les mécanismes de l’exclusion dans les espaces publics. Nous montrons alors comment les stratégies d’appropriation des espaces publics par les riverains, et leur utilisation comme une extension du « chez-soi » participent d’une transformation des valeurs spatiales et de l’émergence d’une « dispersion douce » à l’encontre des personnes marginalisées. Cet article vise ainsi à montrer comment de nouvelles formes de pouvoir, moins visibles que le revanchisme ou la tolérance-zéro, se font jour dans la production des espaces publics, notamment à travers le contrôle des références topologiques.
Équité environnementale et distribution spatiale de la végétation à l’intérieur et autour des îlots résidentiels à Montréal : une double iniquité ?
Authors: Apparicio Philippe , Pham Thi-Thanh-Hiên , Séguin Anne-Marie , Landry Shawn M.
Published: May 2014

De récentes études ont montré que la végétation urbaine est inégalement distribuée au sein de plusieurs métropoles nord-américaines : certains quartiers plus défavorisés ou à forte concentration ethnique présenteraient des niveaux de couverture végétale plus limités. L’objectif de cet article est de vérifier l’existence d’iniquités environnementales en termes d’accès à la végétation urbaine sur le territoire de l’ancienne ville de Montréal pour les personnes à faible revenu et les minorités visibles. Six indicateurs de végétation à l’intérieur et autour des îlots résidentiels (à 250 et 500 m) sont construits à l’aide d’images satellites QuickBird. Puis, ces indicateurs sont mis en relation avec des données socioéconomiques au moyen de plusieurs analyses statistiques (corrélation, test de Student (test t), analyse de variance et analyse de régression). Les résultats démontrent que la population à faible revenu et, dans une moindre mesure, celle des minorités visibles résident dans des environnements où la végétation est moins présente. Finalement, l’utilisation combinée d’indicateurs de végétation à l’intérieur et autour de l’îlot permet de démontrer l’existence d’une double iniquité dans certains secteurs urbains.
Mobilité et lutte contre la pollution atmosphérique
Authors: Gobert Julie
Published: May 2014

Dans un but de développement économique des territoires, les pouvoirs publics sont amenés, en France, à favoriser le « capital mobilité » des individus pour leur donner le moyen d’accéder au marché du travail et à un ensemble de ressources et de services. Toutefois, il est également nécessaire de réguler les problèmes liés à l’automobilité et aux nuisances environnementales qui lui sont inhérentes. Les politiques publiques de transport ont de ce fait évolué : la notion de « droit à la mobilité » se dissout peu à peu au profit d’objectifs plus complexes de développement durable. Ce dilemme entre enjeux économiques, sociaux et environnementaux pose la question des inégalités environnementales, particulièrement quand il s’agit de mettre en place une zone à basse émission sur les grandes agglomérations, comme cela est prévu dans la loi du Grenelle II sous le nom de zone d’actions prioritaires pour l’air (ZAPA). Au regard d’une enquête de terrain menée sur une intercommunalité de Seine-Saint-Denis, en amont de la mise en place d’une ZAPA, nous avons cherché à mieux connaître l’impact d’une telle mesure et les possibles répercussions en termes d’inégalités.
Organisateurs communautaires et développement des communautés
Authors: Parent1 Andrée-Anne , Roy Manon , Lavoie Colette , Gauthier André , O’Neill Michel , Simard Paule
Published: May 2014

La stratégie de soutien au développement des communautés, mise de l’avant par les instances québécoises de santé publique depuis près de dix ans, propose au réseau de la santé et des services sociaux d’intervenir selon une logique sociale territoriale. Comme les organisateurs communautaires de Centres de santé et de services sociaux (CSSS) portent ces interventions au niveau local, nous nous sommes intéressés à l’influence de cette stratégie sur leur pratique. Cet article résume les résultats d’une recherche doctorale menée au CSSS de la Vieille-Capitale, obtenus grâce à la mise en place d’un groupe de pratique réflexif pour les organisateurs communautaires.
Une approche innovante en développement des communautés
Authors: Bourque Denis , Mercier Clément
Published: May 2014

Cet article décrit et analyse l’approche d’animation territoriale dans une perspective de développement durable (ATDD) élaborée dans la région de Lanaudière depuis le début des années 2000. Nous présentons la démarche d’abord en la contextualisant et en la décrivant dans ses principales caractéristiques. Nous situons cette approche dans le contexte plus général de ce type de pratiques s’inscrivant dans le développement des communautés, et en dégageons quelques grands défis et perspectives pour l’intervention et la recherche. Enfin, nous formulons quelques hypothèses explicatives quant aux défis pour la pérennisation d’une telle approche.
On the “very Brink between Time and Eternity”: Truth, Charity, and Last Dying Speeches in England, c. 1660–1700
Authors: McKenzie Andrea
Published: May 2014

Late seventeenth-century England witnessed not only the rise of the coffee-house, the newspaper, and party politics, but also a proliferation of printed accounts of treason trials and executions, exposing hearers and readers to opposing religious and political truth claims. Such last dying words, spoken as they were on the “very Brink between Time and Eternity,” were equally compelling and controversial, dividing opinion along partisan and confessional lines. This study builds on recent scholarship emphasizing the dynamism of the Restoration public sphere and the degree to which the gallows was a contested space. It argues that the pamphlet wars over the meaning, veracity, and authenticity of the last dying speeches of late seventeenth-century condemned traitors, while largely overlooked by scholars of the Restoration crisis, have much to tell us about larger, shared preoccupations and mentalities. This article will focus in particular on two powerful contemporary credos which constrained and shaped the actions of authorities, malefactors, and pamphleteers alike: the equation of freedom of speech with liberty and Protestantism on the one hand and the association of charity with the good death, credibility, and truth, on the other.
Equitable Claims and Future Considerations: Road Building and Colonization in Early Ontario, 1850–1890
Authors: Murray Derek
Published: May 2014

In the 1850s, the government of Canada West initiated a project to colonize a vast “waste land” known as the Ottawa-Huron Tract. Resettlement was encouraged through the building of a network of colonization roads and the offer of free grant lots along the roads. In the backwoods, where topography defied the logic of the grid, the placement and maintenance of roads was crucial, not only for convenience, but for survival. Analysing the process whereby settlers and the state negotiated road construction projects, this article reveals an emerging local democratic culture in which frustration with bureaucracy often meant more to community formation than did social status, religion, or ethnicity. In a series of letters and petitions sent to the colonization roads administration from 1863 to 1888, residents of Brudenell, Ontario, articulated a vision of resettlement in which the state played a supporting rather than determining role. While much has been written about the failure of intensive commercial agriculture on the Precambrian Shield, settlers succeeded in building communities and, sometimes, in channelling government resources toward local initiatives.
Canada’s Invisible Nationality Policy: Creating Ethnicity, Managing Populations, Imagining a Nation
Authors: Efremkin Evgeny
Published: May 2014

This article explores the process of national identity construction at Canadian borders in the 1930s. Based on the examination of customs declaration forms (transatlantic ship manifests) of arriving passengers at the port of Quebec in the first half of the 1930s, as well as Royal Canadian Mountain Police (RCMP) files, I suggest that the Canadian bureaucracy, informed by social Darwinist views of race and ethnicity, and the Anglophone bourgeois concern over modernization brought upon by the forces of industrialization and urbanization, developed an elaborate system of categorization of Canada’s population according to prescribed criteria of ethnicity, nationality, and race. Utilizing critical discourse analysis, I argue that in efforts to “know” and control its growing population, the Canadian state developed a rigid, albeit an invisible nationality policy. Although there was never an official nationality policy in place in Canada in the 1930s, public officials, the media, and security agencies not only operated with an acute awareness of national and ethno-racial differences in the society, but also worked to reinforce such divisions in attempts to maintain the social order and the cultural, social, and economic status quo. In this work, I imply that border officials were directly responsible for constructing specific representations of Canada’s ethnic populations, all within the context of an impending need to control the population of a rapidly modernizing society, where the Canadian community had to be made “knowable,” familiar, and recognizable in the official discourse.
Visions of Friendship and Equality: Representations of African Women in Missionary Propaganda in Interwar Britain
Authors: Hughes Rebecca C.
Published: May 2014

During the interwar years, British evangelical women began to promote African women as worthy of friendship and equality. These representations differed not only from Victorian images of African women, but also those popularized by interwar secular writers. This article argues that the two most prolific female missionary writers of the interwar period, Mabel Shaw and Cicely Hooper, promoted these positive images while working as educators of African women. As feminists, these evangelicals valued African women, and as adherents of fulfillment theology popularized in ecumenical missionary discourse, they admired features of African culture that they believed were divinely inspired. By the late 1920s, these missionary women generated even more favourable images of African women, as they feared Western materialism was disintegrating African home life. Thus, this article demonstrates the liminal position of missionary women tethered to audiences in Britain, Africa, and the growing ecumenical Church. It also points to the importance of the interwar years as a key period in which ideas about race, gender, and culture were being reworked. While these missionary women did not erase boundaries of difference between themselves and African women, they invited Britons to join them in building cross-cultural, cross-racial friendships.
African Canadian Anti-Discrimination Activism and the Transnational Civil Rights
Movement, 1945–1965
Authors: Waters Rosanne
Published: May 2014

Several recent historical works have challenged interpretations of the civil rights
movement in the United States as a strictly domestic story by considering its connections to
anti-racist struggles around the world. Adding a Canadian dimension to this approach, this
article considers linkages between African Canadian anti-discrimination activism in the
1950s and early 1960s and African American civil rights organizing. It argues that Canadian
anti-discrimination activists were interested in and influenced by the American movement.
They followed American civil rights campaigns, adapted relevant ideas, and leveraged the
prominent American example when pressing for change in their own country. African Canadian
activists and organizations also impacted the American movement through financial and moral
support. This article contributes to the study of African Canadian history, Canadian human
rights history, and the American civil rights movement by emphasizing the local origins of
anti-discrimination activism in Canada, while also arguing that such efforts are best
understood when contextualized within a broader period of intensive global anti-racist
activism that transcended national borders.
The Whale and the Region: Orca Capture and Environmentalism in the New Pacific Northwest
Authors: Colby Jason
Published: May 2014

Although the orca is today widely recognized as a cultural and ecological icon of the Pacific Northwest, historians have ignored the impact of killer whale capture on the development of the region’s environmental values and identity. Between 1964 and 1976, the waters in southern British Columbia and Washington State were the world’s principal source of captive killer whales. The display of orcas by the region’s aquariums transformed human perceptions of this marine predator, and soon aquariums around the world were placing orders for Pacific Northwest killer whales. Yet the expanding capture and export of orcas in the late 1960s and early 1970s raised troubling ecological and moral questions for the region’s human residents. In the context of shifting attitudes toward cetaceans and rising environmental awareness throughout North America, Pacific Northwesters on both sides of the border increasingly viewed orcas as symbols of their region’s shared ecological concerns. The transnational nature of the region’s killer whale pods helped spur not only ecological reflection but also transborder cooperation among activists, scientists, and government officials to study and eventually protect the species. In the process, the shifting human relations with orcas helped redefine the Pacific Northwest.
Using Laponite to Deliver BMP‐2 for Bone Tissue Engineering – In Vitro, Chorioallantoic Membrane Assay and Murine Subcutaneous Model Validation
Authors: Marshall Karen M. , Wojciechowski Jonathan P. , Echalier Cécile , Callens Sebastien J. P. , Yang Tao , Øvrebø Øystein , Zhou Kun , Jayawarna Vineetha , Kanczler Janos M. , Stevens Molly M. , Dawson Jonathan I. , Oreffo Richard O.C.
Published: July 2024

Fracture non‐union occurs due to various factors, leading to the development of potentially substantial bone defects. While autograft and allograft are the current gold standards for non‐union fractures, challenges related to availability and immune rejection highlight the need for improved treatments. A strategy in bone tissue engineering is to harness growth factors to induce an effect on cells to change their phenotype, behavior and initiate signaling pathways which lead to increased matrix deposition and tissue formation. Bone morphogenetic protein‐2 (BMP‐2) is a potent osteogenic growth factor however, given its rapid clearance time in vivo, there is a specific therapeutic window for efficacy while avoiding potential deleterious side‐effects. It is demonstrated that a Laponite nanoclay coating on a 3D printable and bioresorbable poly(caprolactone) trimethacrylate‐based resin enables binding of BMP‐2, decreases the rate of release, enabling reduced concentrations to be used while enhancing osteoinduction in both in vitro and in vivo models.
Optomechanical Cavities Based on Epitaxial GaP on Nominally (001)‐Oriented Si
Authors: Mouriño Paula , Mercadé Laura , Sinusía Lozano Miguel , Resta Raquel , Griol Amadeu , Ben Saddik Karim , Barrigón Enrique , Fernández‐Garrido Sergio , García Basilio Javier , Martínez Alejandro , Gómez Víctor J.
Published: July 2024

Gallium Phosphide (GaP) has recently received considerable attention as a suitable material for building photonic integrated circuits due to its remarkable optical and piezoelectric properties. Usually, GaP is grown epitaxially on III–V substrates to keep its crystallinity and later transferred to silicon wafers for further processing. Here, an alternative promising route for the fabrication of optomechanical (OM) cavities on GaP epitaxially grown on nominally (001)‐oriented Si is introduced by using a two‐step process consisting of a low‐temperature etching of GaP followed by selective etching of the underneath silicon. The low‐temperature (–30 °C) during the dry‐etching of GaP hinders the lateral etching rate, preserving the pattern with a deviation between the design and the pattern in the GaP layer lower than 5%, avoiding the complex process of transferring and bonding a GaP wafer to a silicon‐on‐insulator wafer. To demonstrate the quality and feasibility of the proposed fabrication route, suspended OM cavities are fabricated and experimentally characterized. The cavities exhibit optical quality factors between 103 and 104 at telecom wavelengths, and localized mechanical resonances ≈3.1 GHz with quality factors ≈63 when measured at room temperature. These results suggest a simple and low‐cost way to build GaP‐based photonic devices directly integrated on industry‐standard Si(001) photonic wafers.
Intraparticle Electron Transfer for Long‐Lasting Tumor Chemodynamic Therapy
Authors: Yu Jing , Yan Hongmeng , Zhao Fan , Ying Yao , Li Wangchang , Li Juan , Zheng Jingwu , Qiao Liang , Yang Wei , Che Shenglei
Published: July 2024

Chemodynamic therapy (CDT) is a novel tumor treatment method by using hydroxyl radicals (•OH) to kill cancer cells. However, its therapeutic effects are strictly confined by the short lifespan of •OH and reduced •OH generation speed. Herein, an effective CDT is achieved by both improving •OH lifetime and long‐lasting generating •OH through intraparticle electron transfer within heterogeneous nanoparticles (NPs). These heterogeneous NPs are composed of evenly distributed Cu and Fe3O4 (CFO NPs) with large interaction interfaces, and electrons tend to transfer from Cu to Fe3O4 for the appearance of ≡Cu2+ and increase in ≡Fe2+. The generated ≡Cu2+ can interact with GSH, which prolongs the lifespan of •OH, produces ≡Cu+ for higher speed •OH generation with H2O2, and induces cell ferroptosis for tumor therapy. The improved ≡Fe2+ can also improve the •OH release under H2O2 until Cu is depleted. As a result, a sustainable •OH generation is achieved to promote cell apoptosis for effective tumor therapy. Since H2O2 and GSH are only overexpressed at tumor, and CFO NPs can degrade in the tumor microenvironment, these NPs are with high biosafety and can be metabolized by urine. This work provides a novel biomaterial for effective cancer CDT through intraparticle electron transfer.
Base‐Catalyzed Decarboxylative Amination of In‐Situ Generated Ortho‐Quinone Methides: Synthesis of Benzyl Amines
Authors: Ranjan Sahoo Sushree , Subba Parbat , Singh Vinod K.
Published: July 2024

In this paper, a direct access to benzylic amines from in‐situ generated ortho‐quinone methides (o‐QMs) and isocyanate/isothiocyanate via decarboxylation is described. This base‐catalyzed methodology has high functional group tolerance and shows a wide range of substrate scopes, where H2O as a nucleophile for isocyanate/isothiocyanate for product formation. The products are insensitive to air and moisture, which makes this synthetic strategy more efficient for the construction of various benzyl amine derivatives.
Redox‐gesteuertes Entkleben von Muschel‐inspirierten Haftklebstoffen: Effizienzsteigerung durch funktionales Design
Authors: Neubert Tilmann J. , Walter Keven , Schröter Carolin , Guglielmotti Victoria , Hinrichs Karsten , Reinicke Stefan , Taden Andreas , Balasubramanian Kannan , Börner Hans G.
Published: July 2024

Auf dem Weg zur Kreislaufwirtschaft ermöglichen abschaltbare Haftklebstoffe (engl. pressure sensitive adhesives, PSA) Zugang zu Wiederverwertbarkeitsstrategien in der Mikroelektronik. Zwei PSAs wurden aus einem tetravalenten Thiol‐Sternpolyester synthetisiert, der Thiol‐Catechol‐Verknüpfungen (thiol‐catechol‐connectivity, TCC) mit dem biobasierten DiDopa‐Bischinon (BY*Q) oder dem fossilbasierten Bischinon A (BQA) bildet. Die PSAs ermöglichen das Entkleben durch Oxidation der TCC‐Catechole zu Chinonen. Die Ablösungseffizienz hängt von den Interaktionsmoden ab, die aus den unterschiedlichen chemischen Strukturen der beiden TCC‐Motive folgen. BY*Q‐TCC‐PSA zeigt beim Entkleben einen außergewöhnlichen Verlust von 99 % seiner ursprünglichen Scherfestigkeit von ca. 2 MPa in Glas‐auf‐Glas‐Verklebungen. Für BQA‐TCC‐PSA wurde ein Verlust der Scherfestigkeit von nur ca. 60 % festgestellt, unabhängig vom ursprünglichen Wert, der bis auf ca. 7 MPa eingestellt werden konnte. Die Effizienz der Ablösung von BY*Q‐TCC‐PSA nach der TCC‐Oxidation konnte mit dem Verlust synergetischer Wechselwirkungen in Verbindung gebracht werden. Dabei verändern sich die Eigenschaften des Bulk‐Klebstoffs weniger stark als im nur auf Catecholen basierenden BQA‐Analogon.
MnO2@Al‐BDC nanocomposite as adsorbent of remarkable high efficiency toward iron remediation from wastewaters
Authors: Said Mohamed I. , Sayed Marwa , Aly Aref A. M. , Atef Muhammad
Published: July 2024

Global environmental problems, especially those related to water contamination brought on by rapid industrialization and economic growth, are among the most dangerous threats facing humanity today. In this research work, Al3+ based metal–organic framework with 1,4‐benzenedicarboxylic acid (H2BDC) linker has been synthesized by a simple and economic coprecipitation method. The obtained Al‐BDC MOF was utilized as an adsorbent for sequestering iron from wastewater, but only 54.0% of iron concentration was eliminated after 120 min. To boost the removal efficiency, modification of the Al‐BDC MOF was carried out. MnO2@Al‐BDC nanocomposite was prepared and applied as a nanoadsorbent for iron remediation from water. The adsorption capability of Al‐BDC MOF was greatly enhanced by facile modification. The adsorption efficiency reached 97.0% using 35.0 mg of the nanocomposite after 120 min compared to 54.0% iron removal using the un‐modified MOF. The effect of pH of the medium was then studied using MnO2@Al‐BDC nanocomposite. The best elimination efficacy of iron was accomplished at pH ~ 2.2. The adsorption of iron on the surface of MnO2@Al‐BDC nanocomposite attains 97.0% (120 min) using a 35.0 mg dose of adsorbent and reaches 98.7% utilizing a 50.0 mg dose of adsorbent. In contrast, at pH = 9.2, the removal efficiency drops to 90.0% (after 120 min, 35.0 mg adsorbent). The adsorption capability was examined also using a variety of iron concentrations, i.e., 2.5, 5.0, and 7.5 mg/L where the adsorption efficiency dropped notably upon increasing the concentration. It dropped from 96.3% to 87.0% using 35.0 mg of MnO2@Al‐BDC nanocomposite at 90 min. The newly developed adsorbent showed a pronounced efficiency for Fe3+ removal against real samples collected from different water sources. Ultimately, this research introduces a novel MnO2@Al‐BDC nanocomposite, synthesized through a simple and economical coprecipitation method, to address water contamination by iron. The innovation lies in the significant enhancement of iron elimination efficiency, from 54.0% with unmodified Al‐BDC MOF to 97.0% with the MnO2@Al‐BDC nanocomposite.
An effective CaenorhabditiselegansCRISPR training module for high school and undergraduate summer research experiences in molecular biology
Authors: Herrera Sandoval Carmen , Borchers Christopher , Aoki Scott T
Published: July 2024

Engaging in research experiences as a high school or undergraduate student interested in science, technology, engineering, and mathematics (STEM) is pivotal for their academic and professional development. A structured teaching framework can help cultivate a student's curiosity and passion for learning and research. In this study, an eight‐week training program was created to encompass fundamental molecular biology principles and hands‐on laboratory activities. This curriculum focuses on using clustered regularly interspaced short palindromic repeats (CRISPR) gene editing in the Caenorhabditis elegans model organism. Through pre‐ and post‐program assessments, enhancements in students' molecular biology proficiency and enthusiasm for scientific exploration were observed. Overall, this training module demonstrated its accessibility and ability to engage inexperienced students in molecular biology and gene editing methodologies.
Influence of phosphates on phase formation in alkali‐activated MgO‐Al2O3‐SiO2‐P2O5 cements
Authors: Reed Titus , Mauro John C. , Gevaudan Juan Pablo
Published: July 2024

The impact of phosphates on phase formation in low Ca alkali‐activated materials (AAMs) is investigated using a polymer‐assisted sol‐gel process to fabricate MgO‐Al2O3‐SiO2‐P2O5 cement precursors covering a broad range of compositions activated with sodium hydroxide. X‐ray diffraction and magic angle spinning‐nuclear magnetic resonance are used to examine the crystalline and amorphous phases that form over 470 days of curing (35°C, 90% relative humidity). The results confirm that Al is preferentially incorporated into hydrotalcite‐like layered double hydroxides (LDH) over zeolites. Zeolites form when more Al is present than can be incorporated into the LDH. Little evidence of phosphate incorporation into aluminosilicate networks (such as zeolites or disordered aluminosilicate hydrate) was observed. The phosphates present in the precursor favor reaction with sodium to form water‐soluble sodium phosphate phases. In most cases, the remainder of the phosphates become adsorbed to the surface of other phases and are not intercalated into the LDH, though at high phosphate concentrations (26.6 wt. % P2O5) and extended curing times (470 days), phosphates are observed to intercalate into LDH phases. These results provide preliminary evidence that phosphates are compatible with low Ca AAMs, which is consequential as there is a growing interest in both the use of AAM and phosphate‐based corrosion inhibiter in steel‐reinforced concrete.
Comparative structural study on axonemal and cytoplasmic dyneins
Authors: Zimmermann Noemi , Ishikawa Takashi
Published: July 2024

Axonemal dyneins are the driving force of motile cilia, while cytoplasmic dyneins play an essential role in minus‐end oriented intracellular transport. Their molecular structure is indispensable for an understanding of the molecular mechanism of ciliary beating and cargo transport. After some initial structural analysis of cytoplasmic dyneins, which are easier to manipulate with genetic engineering, using X‐ray crystallography and single‐particle cryo‐electron microscopy, a number of atomic and pseudo‐atomic structural analyses of axonemal dyneins have been published. Currently, several structures of dyneins in the post‐power stroke conformation as well as a few structures in the pre‐power stroke conformation are available. It will be worth systematically comparing conformations of dynein motor proteins from different sources and at different states, to understand their role in biological function. In this review, we will overview published high‐ and intermediate‐resolution structures of cytoplasmic and axonemal dyneins, compare the high‐resolution structures of their core motor domains and overall tail conformations at various nucleotide states, and discuss their force generation mechanism.
Spider Silk‐Inspired Hyaluronic Acid‐Based Hydrogels with Superior Self‐Healing Capability and Enhanced Strength
Authors: Yang Kaidan , Zhou Ding , Wang Yachao , Chen Ruina , Dong Qi , Xiao Pu , Zhou Yingshan , Zhang Jing
Published: July 2024

Hyaluronic acid hydrogels are promising materials for diverse applications, yet their potential is hampered by limitations such as low self‐healing efficiency and insufficient mechanical strength. Inspired by the heterogeneous structures of spider silk, we introduce a novel dual dynamically crosslinked network hydrogel. This hydrogel comprises an acylhydrazone‐crosslinked network, utilizing aldehyde hyaluronic acid (AHA) and 3,3′‐dithiobis (propionohydrazide) (DTP) as a first network, and a secondary network formed by hydrogen bonds‐crosslinked network between tannic acid (TA) and silk fibroin (SF) with β‐sheet formation. The hydrogel exhibits exceptional self‐healing ability due to the dynamic and reversible nature of Schiff base bonds, disulfide bonds, and hydrogen bonds, achieving complete healing within 5 minutes. Additionally, the spider silk‐inspired heterogeneous structures enhance mechanical properties. Furthermore, the incorporation of TA provides enhances adhesion, as well as remarkable antibacterial and antioxidant properties. This innovative hyaluronic acid‐based hydrogel, inspired by spider silk, offers a promising avenue to fortify both the mechanical strength and self‐healing capabilities of hydrogels, thus expanding opportunities for applications in tissue engineering and biomedicine.