16 research outputs found
Selected Papers from Experimental Stress Analysis 2020
This Special Issue consists of selected papers from the Experimental Stress Analysis 2020 conference. Experimental Stress Analysis 2020 was organized with the support of the Czech Society for Mechanics, Expert Group of Experimental Mechanics, and was, for this particular year, held online in 19–22 October 2020. The objectives of the conference included identification of current situation, sharing professional experience and knowledge, discussing new theoretical and practical findings, and the establishment and strengthening of relationships between universities, companies, and scientists from the field of experimental mechanics in mechanical and civil engineering. The topics of the conference were focused on experimental research on materials and structures subjected to mechanical, thermal–mechanical, and dynamic loading, including damage, fatigue, and fracture analyses. The selected papers deal with top-level contemporary phenomena, such as modern durable materials, numerical modeling and simulations, and innovative non-destructive materials’ testing
Metal Additive Manufacturing – State of the Art 2020
Additive Manufacturing (AM), more popularly known as 3D printing, is transforming the industry. AM of metal components with virtually no geometric limitations has enabled new product design options and opportunities, increased product performance, shorter cycle time in part production, total cost reduction, shortened lead time, improved material efficiency, more sustainable products and processes, full circularity in the economy, and new revenue streams. This Special Issue of Metals gives an up-to-date account of the state of the art in AM
Wings in Orbit: Scientific and Engineering Legacies of the Space Shuttle, 1971-2010
The Space Shuttle is an engineering marvel perhaps only exceeded by the station itself. The shuttle was based on the technology of the 1960s and early 1970s. It had to overcome significant challenges to make it reusable. Perhaps the greatest challenges were the main engines and the Thermal Protection System. The program has seen terrible tragedy in its 3 decades of operation, yet it has also seen marvelous success. One of the most notable successes is the Hubble Space Telescope, a program that would have been a failure without the shuttle's capability to rendezvous, capture, repair, as well as upgrade. Now Hubble is a shining example of success admired by people around the world. As the program comes to a close, it is important to capture the legacy of the shuttle for future generations. That is what "Wings In Orbit" does for space fans, students, engineers, and scientists. This book, written by the men and women who made the program possible, will serve as an excellent reference for building future space vehicles. We are proud to have played a small part in making it happen. Our journey to document the scientific and engineering accomplishments of this magnificent winged vehicle began with an audacious proposal: to capture the passion of those who devoted their energies to its success while answering the question "What are the most significant accomplishments?" of the longestoperating human spaceflight program in our nation s history. This is intended to be an honest, accurate, and easily understandable account of the research and innovation accomplished during the era
Forum Bildverarbeitung 2016
Bildverarbeitung spielt in vielen Bereichen der Technik zur schnellen und berührungslosen Datenerfassung eine Schlüsselrolle. Der vorliegende Tagungsband des „Forums Bildverarbeitung“, das am 1. und 2. Dezember 2016 in Karlsruhe als Veranstaltung des Karlsruher Instituts für Technologie und des Fraunhofer-Instituts für Optronik, Systemtechnik und Bildauswertung stattfand, enthält die Aufsätze der eingegangenen Beiträge. Darin wird über aktuelle Trends und Lösungen der Bildverarbeitung berichtet
Laser powder bed fusion-centred approach to enable local drug delivery from a cementless hip stem
ENGLISH ABSTRACT: Periprosthetic joint infection (PJI) resulting from colonisation of implant surfaces by pathogenic bacteria
and subsequent biofilm formation is a devastating complication following total hip arthroplasty. It
significantly reduces a patient’s quality of life and, in severe cases, can result in amputation or mortality.
Treatment of PJI is associated with a substantial burden on healthcare and economic resources. The
importance of research towards innovations in PJI prevention and treatment is emphasised.
Local delivery of antimicrobial drugs is an effective approach to prevent and treat PJI as it enables high
local drug concentrations while avoiding systemic side effects. Current practice is considered sub-optimal
and appreciable research exists on the improvement of local drug delivery strategies. For cementless hip
stems the focus tends to be on coatings and conditioning of the external implant surface. A significant
research gap exists between external and internal drug delivery strategies where ‘internal’ refers to the
incorporation of reservoir structures within the implant. Therefore, a prototype strategy utilising the
internal volume of a cementless stem for a reservoir from which an antimicrobial drug can be delivered
directly to the implant surface was investigated. The challenge of fabricating a cementless hip stem with
intricate internal geometries can be effectively addressed through metal additive manufacturing (MAM).
Industry is steadily incorporating MAM into process chains as the main production technology for the
fabrication of high-value functional components. Laser powder bed fusion (LPBF) was applied in this
study as MAM technology to fabricate a Ti6Al4V ELI demonstrator cementless hip stem with local drug
delivery functionality. This required an interdisciplinary approach, for which a problem solving
framework has been synthesised to aid in process chain development from an LPBF-centred perspective. The overall problem was decomposed into integrated partial and single problems which were
systematically investigated through literature study and experimentation. An LPBF-centred solution was
developed for the direct integration of permeable structures in a dense part using an in-process assembly
method. Different levels of porosity were induced into permeable thin walls according to a systematically
identified window for ranges of the process parameters, laser power and scanning speed. This resulted in
tailorable release profiles for the model antibiotic vancomycin from an aqueous formulation. Released
vancomycin retained its antibiotic efficacy against Staphylococcus aureus Xen 36 (methicillin sensitive)
and Staphylococcus aureus Xen 31 (methicillin resistant), representing two of the most frequent pathogens
in PJI. Solutions for single problems were recomposed for integrated solutions to partial problems, and
subsequently for an overall prototype solution. The overall solution cementless hip stem prototype
effectively prevented surface colonisation by Staphylococcus aureus Xen 31, confirming the efficacy of
the developed local drug delivery strategy. These results were used to inductively refine the LPBF-centred
interdisciplinary problem solving framework.
The original contribution of the research corresponds to the experimentation and framework development
phases respectively. This involves the systematic investigation of LPBF to enable local drug delivery and
an LPBF-centred approach for interdisciplinary problem solving. Lastly, it contributes to the advancement
of LPBF by demonstrating the application efficacy of the prototype solution.AFRIKAANSE OPSOMMIMG: Periprostetiese gewrigsinfeksie (PJI) as ‘n gevolg van implantaatoppervlak kolonisasie deur patogeniese
bakterieë en biofilm formasie is ’n ernstige komplikasie na totale heupartroplastiek. Dit verlaag ’n pasiënt
se lewenskwaliteit merkwaardig en kan in ernstige gevalle lei tot amputasie of sterfte. Behandeling van
PJI word geassosieer met ’n substansiële las op gesondheids- en ekonomiese middele. Die belangrikheid
van navorsing vir innovasies in PJI voorkoming en behandeling word benadruk.
Lokale toediening van antimikrobiese medikamente is ‘n effektiewe benadering om PJI te voorkom en te
behandel deurdat hoë lokale antimikrobiese konsentrasies gehandhaaf kan word sonder sistemiese newe-
effekte. Huidige praktyk word beskou as suboptimaal en veel navorsing bestaan vir die verbetering van
lokale toedieningsstrategieë. Vir ongesementeerde heupstamme is die fokus op bedekkings en
kondisionering van die eksterne implantaatoppervlak. ’n Beduidende gaping bestaan tussen eksterne en
interne lokale toedieningsstrategieë waar ‘intern’ verwys na die inkorporasie van reservoirstrukture binne
die implantaat. Daarom was ’n prototipestrategie vir die benutting van die interne volume van ’n
ongesementeerde heupstam vir ’n reservoir waar vanuit medikamente direk na die implantaatoppervlak
toegedien kan word ondersoek. Die uitdaging om ’n ongesementeerde heupstam met ingewikkelde interne
geometrieë te vervaardig kan effektief aangespreek word deur metaal toevoegingsvervaardiging (MAM).
ndustrie is stelselmatig besig om MAM in proseskettings te inkorporeer as die hoof produksietegnologie
vir die vervaardiging van hoë-waarde funksionele komponente. Laser poeierbed fusie (LPBF) is toegepas
in hierdie studie as MAM-tegnologie om ’n Ti6Al4V ELI demonstrasie ongesementeerde heupstam met
lokale medikament toedieningsfunksie te vervaardig. Dit het ’n interdissiplinêre benadering vereis
waarvoor ’n probleemoplossingsraamwerk gesintetiseer was om die proseskettingontwikkeling vanuit ’n
LPBF-gesentreerde perspektief te ondersteun.
Die algehele probleem was opgebreek in geïntegreerde deel- en enkelprobleme wat sistematies ondersoek
was deur literatuur studie en eksperimentasie. ’n LPBF-gesentreerde oplossing was ontwikkel vir die
direkte integrasie van poreuse strukture in ’n digte part met ’n in-proses monteermetode. Verskeie vlakke
van porositeit was geïnduseer in deurlaatbare dun wande volgens ’n stelselmatige geïdentifiseerde venster
vir waardes vir die prosesparameters laser sterkte en skandeer spoed. Dit het geresulteer in aanpasbare
vrystellingsprofiele vir die modelantibiotika vankomisien vanuit ’n wateroplossing. Vrygestelde
vankomisien het antibiotiese effektiwiteit behou teen Staphylococcus aureus Xen 36 (metisillien sensitief)
en Staphylococcus aureus Xen 31 (metisillien weerstandig), verteenwoordigend van twee van die mees
frekwente patogene in PJI.
Oplossings vir enkelprobleme was geherkombineer tot geïntegreerde oplossings vir deelprobleme, en
gevolglik vir ’n algehele prototipe-oplossing. Die algehele oplossing ongesementeerde heupstam prototipe
het oppervlakkolonisasie deur Staphylococcus aureus Xen 31 effektief verhoed wat die funksionaliteit van
die ontwikkelde lokale medikament toedieningsstrategie bevestig. Die resultate was induktief gebruik om
die LPBF-gesentreerde interdissplinêre probleemoplossingsraamwerk te verfyn.
Die oorspronklike bydrae van die navorsing korrespondeer respektiewelik tot die eksperimentele- en
raamwerkontwikkelingsfases. Dit betrek die sistematiese ondersoek van LPBF om lokale
medikamenttoediening te bewerkstellig en ’n LPBF-gesentreerde raamwerk vir interdissiplinêre
probleemoplossing. Laastens dra dit by tot die bevordering van LPBF deur die toepassingseffektiwiteit
van die prototipe-oplossing te demonstreer.Doctora
Safety and Reliability - Safe Societies in a Changing World
The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management
- mathematical methods in reliability and safety
- risk assessment
- risk management
- system reliability
- uncertainty analysis
- digitalization and big data
- prognostics and system health management
- occupational safety
- accident and incident modeling
- maintenance modeling and applications
- simulation for safety and reliability analysis
- dynamic risk and barrier management
- organizational factors and safety culture
- human factors and human reliability
- resilience engineering
- structural reliability
- natural hazards
- security
- economic analysis in risk managemen