Ultrathin PbTiO3 nanowires can have switchable straight or vortex polarization configurations depending on their termination and strain. PbO termination and tensile strain favor straight polarization while TiO2 termination and compressive strain favor vortex polarization. The static and optical dielectric permittivity is significantly enhanced along the axial direction but reduced in other directions due to depolarizing fields. Nanowires with vortex polarization are expected to have particularly large dielectric permittivity.
Theory of phonon-assisted luminescence: application to h-BNClaudio Attaccalite
In this talk, I present a theory of phonon-assisted luminescence in terms of non-equilibrium Green's functions and time-dependent perturbation theory. This theory is then applied to the phonon-assisted luminescence in hexagonal boron nitride
Los días 22 y 23 de junio de 2016 organizamos en la Fundación Ramón Areces un simposio internacional sobre 'Materiales bidimensionales: explorando los límites de la física y la ingeniería'. En colaboración con el Massachusetts Institute of Technology (MIT), científicos de este prestigioso centro de investigación mostraron las propiedades únicas de materiales como el grafeno, de solo un átomo de espesor, y al mismo tiempo más resistente que el acero y mucho más ligero.
Theory of phonon-assisted luminescence: application to h-BNClaudio Attaccalite
In this talk, I present a theory of phonon-assisted luminescence in terms of non-equilibrium Green's functions and time-dependent perturbation theory. This theory is then applied to the phonon-assisted luminescence in hexagonal boron nitride
Los días 22 y 23 de junio de 2016 organizamos en la Fundación Ramón Areces un simposio internacional sobre 'Materiales bidimensionales: explorando los límites de la física y la ingeniería'. En colaboración con el Massachusetts Institute of Technology (MIT), científicos de este prestigioso centro de investigación mostraron las propiedades únicas de materiales como el grafeno, de solo un átomo de espesor, y al mismo tiempo más resistente que el acero y mucho más ligero.
The 2015 Millennial Majority Workforce: Study ResultsElance-oDesk
Millennials will be the largest generation in the U.S. workforce as of 2015. Yet businesses have a difficult time hiring members of this youngest professional generation. Disjoints abound as the nation’s workforce shifts -- millions of jobs remain unfilled while many millennials struggle to build careers. This study reveals changes in how we work, generational differences, and the critical role millennials play for businesses as we move forward.
Magnetism and magnetic interactions in graphene and graphiteOleg Yazyev
Invited talk D32.00004
Focus Session D32: Spin Dependent Physics in Organic Materials and Graphene
March meeting of the American Physical Society, Pittsburgh
March 16-20, 2009
An automated and user-friendly optical tweezers for biomolecular investigat...Dr. Pranav Rathi
An automated and user-friendly optical tweezers for biomolecular investigations; a versatile, automated, fast, precise and user friendly optical tweezers capable of doing verity of biomolecular experiments.
Slides of my talk at IISc Bangalore on nanomechanics and finite element analysis for statics and dynamics of nanoscale structures such as carbon nanotube, graphene, ZnO nanotube and BN nano sheet.
Jay amrit kapitza resistance at niobiumsuperfluid he interfacesthinfilmsworkshop
Heat removal from SRF cavity walls to superfluid (HeII) plays a decisive on the thermo-magnetic stability and therefore on the performance of these cavities. The two main parameters are the thermal conductivity of Niobium and the thermal boundary resistance (Kapitza resistance) at the Niobium/superfluid He interface. Here we shall focus mainly on the Kapitza resistance .Theoretical models shall be present to demonstrate that the Kapitza resistance is anomalous at the Niobium/HeII interface, justifying the empirical experimental approach. Various sets of data shall be presented for polycrystalline and single crystal Niobium having different surface morphologies and bulk purities. The impact of surface impurities and dislocations on the Kapitza resistance shall be discussed. New analysis shall be present showing an intrinsic limit to the Kapitza resistance due to interactions between phonons (heat carriers) in He-II and the nanoscale surface roughness of Niobium surface. Potential future experiments shall be proposed.
Brandt - Superconductors and Vortices at Radio Frequency Magnetic Fieldsthinfilmsworkshop
Superconductors and Vortices at Radio Frequency Magnetic Fields (Ernst Helmut Brandt - 50')
Speaker: Ernst Helmut Brandt - Max Planck Institute for Metals Research, D-70506 Stuttgart, Germany | Duration: 50 min.
Abstract
After an introduction to superconductivity and Abrikosov vortices, the statics and dynamics of pinned and unpinned vortices in bulk and thin film superconductors is presented. Particular interesting is the case of Niobium, which has a Ginzburg-Landau parameter near 0.71, the boundary between type-I and type-II superconductors. This causes the appearance of a so called type-II/1 state in which the vortex lattice forms round or lamellar domains that are surrounded by ideally superconducting Meissner state. This state has been observed by decoration experiments and by small-angle neutron scattering.
Also considered are the ac losses caused at the surface of clean superconductors, in particular Niobium, in the Meissner state, when no vortices have yet penetrated. The linear ac response is then xpressed by a complex resistivity or complex magnetic penetration depth, or by a surface impedance. At higher amplitudes, several effects can make the response nonlinear and increase the ac losses.
In particular, at sharp edges or scratches of a rough surface the magnetic field is strongly enhanced by demagnetization effects and the induced current may reach its depairing limit, leading to the nucleation of short vortex segments. Strong ac losses appear when such vortex segments oscillate. In high-quality microwave cavities the nucleation of vortices has thus to be avoided. Once nucleated, some vortices may remain in the superconductor even when the applied magnetic field goes through zero. This phenomenon of flux-trapping is caused by weak pinning in the bulk or by surface pinning.
Science Cafe Discovers a New Form of Alternative EnergyEngenuitySC
These are the slides from the May Science Cafe featuring Dr. MVS Chandrashekhar. During this cafe he discussed his work with graphene a new, clean energy source.
Multiscale methods for next generation graphene based nanocomposites is proposed. This approach combines atomistic finite element method and classical continuum finite element method.
I gave 1 hour seminar at ANSTO (Australian Nuclear Science and Technology Organization) to introduce my approach to magnetism. I see myself as an experimental physicist who is studying magnetism by using neutron scattering techniques. Throughout my career, I had learned local structure analysis (PDF), magnetic structural analysis, and inelastic neutron scattering technique to investigate superconductor, multiferroics, antiferromagnets, helimagnets, and frustrated magnets. I was trying to explain my approach to magnetism as an experiment physicist to both professional scientists and novices.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
Le nuove frontiere dell'AI nell'RPA con UiPath Autopilot™UiPathCommunity
In questo evento online gratuito, organizzato dalla Community Italiana di UiPath, potrai esplorare le nuove funzionalità di Autopilot, il tool che integra l'Intelligenza Artificiale nei processi di sviluppo e utilizzo delle Automazioni.
📕 Vedremo insieme alcuni esempi dell'utilizzo di Autopilot in diversi tool della Suite UiPath:
Autopilot per Studio Web
Autopilot per Studio
Autopilot per Apps
Clipboard AI
GenAI applicata alla Document Understanding
👨🏫👨💻 Speakers:
Stefano Negro, UiPath MVPx3, RPA Tech Lead @ BSP Consultant
Flavio Martinelli, UiPath MVP 2023, Technical Account Manager @UiPath
Andrei Tasca, RPA Solutions Team Lead @NTT Data
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
A tale of scale & speed: How the US Navy is enabling software delivery from l...sonjaschweigert1
Rapid and secure feature delivery is a goal across every application team and every branch of the DoD. The Navy’s DevSecOps platform, Party Barge, has achieved:
- Reduction in onboarding time from 5 weeks to 1 day
- Improved developer experience and productivity through actionable findings and reduction of false positives
- Maintenance of superior security standards and inherent policy enforcement with Authorization to Operate (ATO)
Development teams can ship efficiently and ensure applications are cyber ready for Navy Authorizing Officials (AOs). In this webinar, Sigma Defense and Anchore will give attendees a look behind the scenes and demo secure pipeline automation and security artifacts that speed up application ATO and time to production.
We will cover:
- How to remove silos in DevSecOps
- How to build efficient development pipeline roles and component templates
- How to deliver security artifacts that matter for ATO’s (SBOMs, vulnerability reports, and policy evidence)
- How to streamline operations with automated policy checks on container images
The Metaverse and AI: how can decision-makers harness the Metaverse for their...Jen Stirrup
The Metaverse is popularized in science fiction, and now it is becoming closer to being a part of our daily lives through the use of social media and shopping companies. How can businesses survive in a world where Artificial Intelligence is becoming the present as well as the future of technology, and how does the Metaverse fit into business strategy when futurist ideas are developing into reality at accelerated rates? How do we do this when our data isn't up to scratch? How can we move towards success with our data so we are set up for the Metaverse when it arrives?
How can you help your company evolve, adapt, and succeed using Artificial Intelligence and the Metaverse to stay ahead of the competition? What are the potential issues, complications, and benefits that these technologies could bring to us and our organizations? In this session, Jen Stirrup will explain how to start thinking about these technologies as an organisation.
Essentials of Automations: The Art of Triggers and Actions in FMESafe Software
In this second installment of our Essentials of Automations webinar series, we’ll explore the landscape of triggers and actions, guiding you through the nuances of authoring and adapting workspaces for seamless automations. Gain an understanding of the full spectrum of triggers and actions available in FME, empowering you to enhance your workspaces for efficient automation.
We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdf
Polarization, strain induced phase transitions and dielectric response in ultrathin PbTiO3 nanowires
1. Polarization, strain induced phase
transitions and dielectric response in
ultrathin PbTiO3 nanowires
G. Pilania and R. Ramprasad
Chemical, Materials & Biomolecular Engineering
Institute of Materials Science
University of Connecticut
APS March Meeting 2012, Boston, MA
Session J32: Focus Session: Dielectric, Ferroelectric, and Piezoelectric
Oxides - Domain Structures and Switching
Tuesday, February 28, 2012
http://www.ims.uconn.edu/~rampi/
2. Ferroelectric Nanostructures: Applications!
Information Storage Energy Storage
1 2
Emax = εEB
2
Polymer matrix!
J. M. Gregg, Nature Nanotech. 3, 380 - 381 (2008) !
Ferroelectric nanoparticles!
W. Lee et al. Nature Nanotech. 3, 402–407 (2008)! Kim et al. ACS Nano, 3, 2581–2592, 2009!
3. Ultrathin PbTiO3 Nanowires Do
Have Sharp {001} Facets!
Surface Energies ! BaTiO3 nanorod! PbTiO3 nanorod!
(in eV per surface cell)!
Urban et al. Am. Chem. H. Deng et al., J. Mater. Chem.!
R. I. Eglitis, D. Vanderbilt, PRB 76, 155439 (2007)! Soc. 2002, 124, 1186! 2009, 19, 976–982!
4. Ultrathin PbTiO3 Nanowires: Model Details
!
(2x2) PbO-terminated !
Nanowire!
c!
c! [001]!
(2x2) TiO2-terminated !
Nanowire!
G. Pilania and R. Ramprasad, Phys. Rev. B 82, 155442 (2010)!
5. Ground State Polarization in
PbTiO3 Nanowires
c tetragonal Bulk Fa
c!
Fa Fa
Fa
acubic Bulk
c (Å)
P
Fv c!
P
P
Fa=Ferroelectric (axial)!
P=Paraelectric!
Fv=Ferroelectric (vortex)!
(1x1)! (2x2)! (3x3)! (4x4)!
9. Effect of axial strain
PbTiO3 nanowires display switchable rectilinear (axial)
and non-rectilinear (vortex) polarization configurations!
10. Dielectric Permittivity"
PbTiO3 Nanowires
!
(4x4) TiO2-terminated ! (4x4) PbO-terminated !
Nanowire! Nanowire!
Vacuum + Nanowire
Composite
G. Pilania and R. Ramprasad, J. Materials Science 2012
(Special issue: Recent Advances in First Principles Computations in Materials Research )
11. A hybrid approach:"
DFPT + Effective Medium Theory!
α cell = ηV α wire
ε ii − 1
α= Polarizability !∝
1+ (ε ii − 1)Pi
Acell
Vcell
1
Awire
Vwire Pz = 0 Px,y =
2
Axial Off-axis
⎛ ε ii − 1 ⎞ ⎛ ε ii − 1 ⎞
wire
(ε ii − 1) = ηV (ε − 1) ⎜ ε + 1 ⎟ = ηV ⎜ ε wire 1 ⎟
wire
ii ⎝ ii ⎠ ⎝ ii + ⎠
12. DFPT + Effective Medium Theory
ηV ηV
Vary volume fraction occupied by wire
in the supercell by changing size of
the supercell!
15. Summary!
Polarization States in PbTiO3 Nanowires
u Ultra-thin PbTiO3 nanowires display switchable rectilinear (axial) and non-
rectilinear (vortex) polarization configurations.!
u PbO-termination and axial tensile strain favor axial polarization state.!
u TiO2-termination and axial compressive strain favor axial polarization state.!
Dielectric Permittivity of PbTiO3 Nanowires
u Static and optical dielectric permittivity along the axial direction gets
enhanced significantly.!
u Permittivity along the off-axis directions is reduced, owing to the
depolarizing field.!
u Nanowires with exotic vortex polarization states are expected to have a larger
dielectric permittivity.!