scholarly journals Silver Hardening via Hypersonic Impacts

MRS Advances ◽  
2018 ◽  
Vol 3 (8-9) ◽  
pp. 493-498 ◽  
Author(s):  
Eliezer Fernando Oliveira ◽  
Pedro Alves da Silva Autreto ◽  
Douglas Soares Galvão
Keyword(s):  
Rigid Wall ◽  
Strengthening Mechanism ◽  
Research Area ◽  
Single Step ◽  
High Impact ◽  
Step Method ◽  
Silver Nanocubes ◽  
Active Research ◽  
Dynamics Simulations ◽  
The Impact

ABSTRACTThe search for new ultra strong materials has been a very active research area. With relation to metals, a successful way to improve their strength is by the creation of a gradient of nanograins (GNG) inside the material. Recently, R. Thevamaran et al. [Science v354, 312-316 (2016)] propose a single step method based on high velocity impact of silver nanocubes to produce high-quality GNG. This method consists of producing high impact collisions of silver cubes at hypersonic velocity (∼400 m/s) against a rigid wall. Although they observed an improvement in the mechanical properties of the silver after the impact, the GNG creation and the strengthening mechanism at nanoscale remain unclear. In order to gain further insights about these mechanisms, we carried out fully atomistic molecular dynamics simulations (MD) to investigate the atomic conformations/rearrangements during and after high impact collisions of silver nanocubes at ultrasonic velocity. Our results indicate the co-existence of polycrystalline arrangements after the impact formed by core HCP domains surrounded by FCC ones, which could also contribute to explain the structural hardening.

scholarly journals E-Mail Usage in South Pacific Distance Education

2005 ◽  
pp. 1034-1039
Author(s):  
Jonathan Frank ◽  
Janet Toland ◽  
Karen D. Schenk
Keyword(s):  
Learning Styles ◽  
Research Area ◽  
Web Based ◽  
Group Interactions ◽  
Face To Face ◽  
Web Based Learning ◽  
Active Research ◽  
The Impact ◽  
E Mail ◽  
Active Research Area

The impact of cultural diversity on group interactions through technology is an active research area. Current research has found that a student’s culture appears to influence online interactions with teachers and other students (Freedman & Liu, 1996). Students from Asian and Western cultures have different Web-based learning styles (Liang & McQueen, 1999), and Scandinavian students demonstrate a more restrained online presence compared to their more expressive American counterparts (Bannon, 1995). Differences were also found across cultures in online compared to face-to-face discussions (Warschauer, 1996). Student engagement, discourse, and interaction are valued highly in “western” universities. With growing internationalization of western campuses, increasing use of educational technology both on and off campus, and rising distance learning enrollments, intercultural frictions are bound to increase.

scholarly journals E-Mail Usage in South Pacific Distance Education

2011 ◽  
pp. 2325-2332
Author(s):  
Jonathan Frank ◽  
Janet Toland ◽  
Karen D. Schenk
Keyword(s):  
Learning Styles ◽  
Research Area ◽  
Web Based ◽  
Group Interactions ◽  
Face To Face ◽  
Web Based Learning ◽  
Active Research ◽  
The Impact ◽  
E Mail ◽  
Active Research Area

The impact of cultural diversity on group interactions through technology is an active research area. Current research has found that a student’s culture appears to influence online interactions with teachers and other students (Freedman & Liu, 1996). Students from Asian and Western cultures have different Web-based learning styles (Liang & McQueen, 1999), and Scandinavian students demonstrate a more restrained online presence compared to their more expressive American counterparts (Bannon, 1995). Differences were also found across cultures in online compared to face-to-face discussions (Warschauer, 1996). Student engagement, discourse, and interaction are valued highly in “western” universities. With growing internationalization of western campuses, increasing use of educational technology both on and off campus, and rising distance learning enrollments, intercultural frictions are bound to increase.

Urea homogeneous nucleation mechanism is solvent dependent

2015 ◽  
Vol 179 ◽  
pp. 291-307 ◽  
Author(s):  
Matteo Salvalaglio ◽  
Marco Mazzotti ◽  
Michele Parrinello
Keyword(s):  
Finite Size ◽  
Single Step ◽  
Crystal Nucleation ◽  
Primary Role ◽  
Nucleation Process ◽  
Polymorphic Transitions ◽  
Dynamics Simulations ◽  
A Minor ◽  
Energy Surfaces ◽  
The Impact

The composition of the mother phase plays a primary role in crystallization processes, affecting both crystal nucleation and growth. In this work, the influence of solvents on urea nucleation has been investigated by means of enhanced sampling molecular dynamics simulations. We find that, depending on the solvent, the nucleation process can either follow a single-step or a two-step mechanism. While in methanol and ethanol a single-step nucleation process is favored, in acetonitrile a two-step process emerges as the most likely nucleation pathway. We also find that solvents have a minor impact on polymorphic transitions in the early stages of urea nucleation. The impact of finite size effects on the free energy surfaces is systematically considered and discussed in relation to the simulation setup.

scholarly journals Impact Resistance of Bendable Concrete Reinforced with Grids and Containing PVA Solution

2021 ◽  
Vol 11 (5) ◽  
pp. 7709-7713
Author(s):  
S. Abd Al Kareem ◽  
I. F. Ahmed
Keyword(s):  
Compressive Strength ◽  
Building Materials ◽  
Elastic Fiber ◽  
Impact Resistance ◽  
Research Area ◽  
Steel Mesh ◽  
Portland Limestone Cement ◽  
Reinforced Cement ◽  
Active Research ◽  
The Impact

The development of new building materials, able of absorbing more energy is an active research area. Engineering Cementitious Composite (ECC) is a class of super-elastic fiber-reinforced cement composites characterized by high ductility and tight crack width control. The use of bendable concrete produced from Portland Limestone Cement (PLC) may lead to an interest in new concrete mixes. Impact results of bendable concrete reinforced with steel mesh and polymer fibers will provide data for the use of this concrete in areas subject to impact loading. The experimental part consisted of compressive strength and impact resistance tests along with a result comparison with unreinforced concrete. Concrete samples, with dimensions of 100×100×100mm (cubes), and 500×500×50mm (slabs), were poured and were treated at ages of 28, 56, and 90 days. The compressive strength increased by 36.11%, 45.5%, and 52.4% respectively, whereas the impact resistance for samples reinforced with steel mesh and polypropylene fibers gave superior results to the conventional mixes.

scholarly journals Personal Assistants for Human Organizations

2009 ◽  
pp. 514-540 ◽  
Author(s):  
Steven Okamoto ◽  
Katia Sycara ◽  
Paul Scerri
Keyword(s):  
Organizational Performance ◽  
New Technology ◽  
Organizational Structures ◽  
Research Area ◽  
Intelligent Software ◽  
Personal Assistant ◽  
Active Research ◽  
Personal Assistants ◽  
And Performance ◽  
The Impact

Intelligent software personal assistants are an active research area with the potential to revolutionize the way that human organizations operate, but there has been little research quantifying how they will impact organizational performance or how organizations will or should adapt in response. In this chapter we develop a computational model of the organization to evaluate the impact different proposed assistant abilities have on the behavior and performance of the organization. By varying the organizational structures under consideration, we can identify which abilities are most beneficial, as well as explore how organizations may adapt to best leverage the new technology. The results indicate that the most beneficial abilities for hierarchical organizations are those that improve load balancing through task allocation and failure recovery, while for horizontal organizations the most beneficial abilities are those that improve communication. The results also suggest that software personal assistant technology will facilitate more horizontal organizations.

Palladium-Catalyzed Cascade Reactions for Annulative π -Extension of Indoles to Carbazoles through C–H Bond Activation

2020 ◽  
Vol 24 (22) ◽  
pp. 2612-2633
Author(s):  
Enakshi Dinda ◽  
Samir Kumar Bhunia ◽  
Ranjan Jana
Keyword(s):  
Bond Activation ◽  
Photophysical Properties ◽  
Underlying Mechanism ◽  
Direct Conversion ◽  
Cascade Reactions ◽  
Research Area ◽  
Single Step ◽  
Palladium Catalyzed ◽  
Pharmaceutical Industries ◽  
Active Research

The annulative π-extension (APEX) reactions through C-H bond activation has tremendous potential to access fused aromatic systems from relatively simple aromatic compounds in a single step. This state-of-the-art technique has the ability to streamline the synthesis of functionalized materials useful in material science, biomedical research, agroand pharmaceutical industries. Furthermore, C-H activation strategy does not require prefunctionalization steps, which allows for the late-stage modification of the functional molecule with requisite molecular properties. Owing to their unique photophysical properties, carbazoles are widely used in photovoltaic cells, biomedical imaging, fluorescent polymer, etc. It is also ubiquitously found in many natural products, agrochemicals and privileged medicinal scaffolds. Hence, direct conversion of easily accessible indole to carbazole remains an active research area. In the last decades, significant advancement has been made to access carbazole moiety directly from indole through cascade C-H activation. The underlying mechanism behind this cascade π-extension strategy is the facile electrophilic metalation at the C-3 position of the indole moiety, 1,2- migration and electro cyclization. In this review, we will discuss recent literature reports for the palladium-catalyzed π-extension of indole to carbazole moiety through C-H bond activation.

Departure of the Expert Systems Project Champion

2005 ◽  
pp. 797-801
Author(s):  
Janice C. Sipior
Keyword(s):  
Learning Styles ◽  
Research Area ◽  
Web Based ◽  
Group Interactions ◽  
Face To Face ◽  
Online Interactions ◽  
Web Based Learning ◽  
Active Research ◽  
The Impact ◽  
Active Research Area

The impact of cultural diversity on group interactions through technology is an active research area. Current research has found that a student’s culture appears to influence online interactions with teachers and other students (Freedman & Liu, 1996). Students from Asian and Western cultures have different Web-based learning styles (Liang & McQueen, 1999), and Scandinavian students demonstrate a more restrained online presence compared to their more expressive American counterparts (Bannon, 1995). Differences were also found across cultures in online compared to face-to-face discussions (Warschauer, 1996). Student engagement, discourse, and interaction are valued highly in “western” universities. With growing internationalization of western campuses, increasing use of educational technology both on and off campus, and rising distance learning enrollments, intercultural frictions are bound to increase.

Piezoelectric β-polymorph formation of new textiles by surface modification with coating process based on interfacial interaction on the conformational variation of poly (vinylidene fluoride) (PVDF) chains

2020 ◽  
Vol 91 (3) ◽  
pp. 31301
Author(s):  
Nabil Chakhchaoui ◽  
Rida Farhan ◽  
Meriem Boutaldat ◽  
Marwane Rouway ◽  
Adil Eddiai ◽  
...  
Keyword(s):  
High Efficiency ◽  
Vinylidene Fluoride ◽  
Research Work ◽  
Research Area ◽  
Interfacial Interaction ◽  
Tetraethyl Orthosilicate ◽  
Poly Vinylidene Fluoride ◽  
Carbon Nanofillers ◽  
The Impact ◽  
Advanced Applications

Novel textiles have received a lot of attention from researchers in the last decade due to some of their unique features. The introduction of intelligent materials into textile structures offers an opportunity to develop multifunctional textiles, such as sensing, reacting, conducting electricity and performing energy conversion operations. In this research work nanocomposite-based highly piezoelectric and electroactive β-phase new textile has been developed using the pad-dry-cure method. The deposition of poly (vinylidene fluoride) (PVDF) − carbon nanofillers (CNF) − tetraethyl orthosilicate (TEOS), Si(OCH2CH3)4 was acquired on a treated textile substrate using coating technique followed by evaporation to transform the passive (non-functional) textile into a dynamic textile with an enhanced piezoelectric β-phase. The aim of the study is the investigation of the impact the coating of textile via piezoelectric nanocomposites based PVDF-CNF (by optimizing piezoelectric crystalline phase). The chemical composition of CT/PVDF-CNC-TEOS textile was detected by qualitative elemental analysis (SEM/EDX). The added of 0.5% of CNF during the process provides material textiles with a piezoelectric β-phase of up to 50% has been measured by FTIR experiments. These results indicated that CNF has high efficiency in transforming the phase α introduced in the unloaded PVDF, to the β-phase in the case of nanocomposites. Consequently, this fabricated new textile exhibits glorious piezoelectric β-phase even with relatively low coating content of PVDF-CNF-TEOS. The study demonstrates that the pad-dry-cure method can potentially be used for the development of piezoelectric nanocomposite-coated wearable new textiles for sensors and energy harvesting applications. We believe that our study may inspire the research area for future advanced applications.

Purification of Urokinase from Complex Mixtures Using Immobilized Monoclonal Antibody Against Urokinase Light Chain

1983 ◽  
Vol 49 (01) ◽  
pp. 024-027 ◽  
Author(s):  
David Vetterlein ◽  
Gary J Calton
Keyword(s):  
Monoclonal Antibody ◽  
Light Chain ◽  
Culture Media ◽  
Biological Fluids ◽  
Single Step ◽  
High Yield ◽  
Step Method ◽  
Commercial Preparation ◽  
E Coli ◽  
Tissue Culture Media

SummaryThe preparation of a monoclonal antibody (MAB) against high molecular weight (HMW) urokinase light chain (20,000 Mr) is described. This MAB was immobilized and the resulting immunosorbent was used to isolate urokinase starting with an impure commercial preparation, fresh urine, spent tissue culture media, or E. coli broth without preliminary dialysis or concentration steps. Monospecific antibodies appear to provide a rapid single step method of purifying urokinase, in high yield, from a variety of biological fluids.

Document Image Quality Assessment with Relaying Reference to Determine Minimum Readable Resolution for Compression

2020 ◽  
Vol 2020 (9) ◽  
pp. 323-1-323-8
Author(s):  
Litao Hu ◽  
Zhenhua Hu ◽  
Peter Bauer ◽  
Todd J. Harris ◽  
Jan P. Allebach
Keyword(s):  
Image Quality ◽  
Quality Assessment ◽  
Image Quality Assessment ◽  
Research Area ◽  
Input Image ◽  
Quality Score ◽  
Document Image ◽  
Digital Cameras ◽  
Active Research ◽  
Traditional Approaches

Image quality assessment has been a very active research area in the field of image processing, and there have been numerous methods proposed. However, most of the existing methods focus on digital images that only or mainly contain pictures or photos taken by digital cameras. Traditional approaches evaluate an input image as a whole and try to estimate a quality score for the image, in order to give viewers an idea of how “good” the image looks. In this paper, we mainly focus on the quality evaluation of contents of symbols like texts, bar-codes, QR-codes, lines, and hand-writings in target images. Estimating a quality score for this kind of information can be based on whether or not it is readable by a human, or recognizable by a decoder. Moreover, we mainly study the viewing quality of the scanned document of a printed image. For this purpose, we propose a novel image quality assessment algorithm that is able to determine the readability of a scanned document or regions in a scanned document. Experimental results on some testing images demonstrate the effectiveness of our method.

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