10,134 research outputs found
A method for in situ SEM fracture studies of brittle materials using the double torsion technique : application to nuclear graphite
No full textThis work concerned the design and development of a miniature double torsion (DT) testing rig, for use inside the chamber of a scanning electron microscope, to perform in situ loading studies of brittle materials using the DT fracture mechanics specimen. The in situ performance of the system inside the SEM was highly satisfactory, while still providing free rotation of the attached stepper motor. Crack growth rates of down to 19nm/s were directly observed in PMMA specimens. It was concluded that the technique displayed merit in its ability to contribute to the knowledge base of slow cracking and damage development in brittle materials, with the advantage being that the gearing ratios of the current device resulted in slower specimen loading rates, which were more controlled, than reported previously
Data-driven assessment of technical skills in minimally invasive surgery
No full textThis thesis explores the integration of data-driven assessment into minimally invasive surgical (MIS) training. By embedding force-, motion-, and time-based metrics into simulation curricula, it aims to provide objective, individualized feedback and enable competency-based progression. Across the studies, more than 50,000 performances were analyzed, making this one of the largest datasets on MIS skill development. Part I (Chapter 2) reviews 35 studies on data-driven tools for laparoscopic training. Although validity evidence has steadily grown, implementation into curricula remains inconsistent. Metrics and targeted skills varied widely, with most systems focused on motion analysis while domains such as tissue handling and safe force application were underrepresented. Part II examines the application of data-driven assessment in laparoscopic training. A pilot study (Chapter 3) showed that the Lapron box simulator could differentiate novices from experts and support autonomous at-home training, with all participants reaching proficiency. A multicenter prospective cohort (Chapter 4) used regression-based learning curves to visualize progress, identifying both underperforming residents and those ready for advancement, laying the foundation for individualized training. Chapter 5 compared assessment methods for progression from basic to advanced suturing, finding good skill transfer but highlighting the need to align tools with training goals. Chapter 6 showed that haptic exploration before training improved tissue handling, supporting inclusion of sensory elements. Prediction and retention were addressed in Chapters 7 and 8. From early performance data, the required number of repetitions to reach proficiency could be predicted after only three attempts, enabling personalized schedules. A retention study showed significant deterioration after four months, emphasizing the need for maintenance training. Part III extends these principles to advanced and robotic MIS. Chapter 9 introduced a TaTME training platform with force and torque sensors. Skills improved, but excessive force remained common, stressing the need for repetitive training with feedback. Chapter 10 surveyed European surgeons on steerable laparoscopic instruments (SLI). While interest was high, routine use was limited by concerns about learning curves, safety, cost, and sustainability. Chapter 11 presented a reusable, modular SLI prototype that combined robust mechanics with improved reusability. Robotic training was the focus of Chapters 12–15. Chapter 12 validated force and motion metrics for robotic tissue handling. Chapter 13 showed that experts transferred skills seamlessly between laparoscopy and robotics, while novices and intermediates did not, underlining the need for structured training. Chapter 14, using ex vivo cholecystectomy, demonstrated that robotic training led to higher OSATS scores, fewer errors, and greater motion efficiency, with participants also reporting better ergonomics. Chapter 15 introduced PoLaRS, a portable, robot-independent VR simulator, which showed comparable outcomes to the da Vinci Skills Simulator while offering affordability and accessibility. General discussion This thesis highlights the transformative role of data-driven assessment in MIS education. Validated metrics enable real-time feedback, detailed learning curve analysis, and early detection of underperforming trainees. Compared with traditional methods, this approach supports deliberate practice, peer benchmarking, and flexible, remote training. Artificial intelligence and machine learning promise further advances, such as adaptive feedback and predictive modeling. Ultimately, data-driven, competency-based curricula provide a scalable and personalized framework for surgical training, improving skill acquisition, standardization, and patient safety
‘Cleanroom’ in SEM
No full textTo allow researchers to fabricate micro- and nano-devices on a small scale, without having to use complex cleanroom facilities, a single tool is proposed in which a variety of typical cleanroom techniques and processes is combined. This ‘cleanroom’ in SEM tool, based on a scanning electron microscope (SEM), integrates several add-on tools, such as a miniature plasma source for sputtering and cleaning purposes, a miniature thermal evaporator for metal deposition, and facilities to enable in-situ selective atomic layer deposition. The cleanroom techniques and processes selected for integration in the ‘cleanroom’ in SEM tool are discussed, and the design and fabrication of the add-on tools are presented. Finally the proofs of principle of the plasma source, evaporator and in-situ selective ALD process are experimentally demonstrated.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.ImPhys/Microscopy Instrumentation & TechniquesImPhys/Charged Particle Optic
SEM-EDX hyperspectral data analysis for the study of soil aggregates
No full textScanning electron microscopy coupled with microanalysis (SEM-EDX) is an important analytical tool for the morphological and chemical characterization of different types of materials. In many applications, SEM-EDX elemental maps are usually used and processed as images, thus flattening and reducing the spectroscopic information contained in EDX hyperspectral data cubes. The exploitation of the full hyperspectral dataset could be indeed very useful for the study of complex matrices like soil. In order to maximize the information attainable by SEM-EDX data cubes analysis, the software package “Datamuncher Gamma” was implemented and applied to study soil aggregates. By using this approach, different phases (silicates, aluminosilicates, Ca-carbonates, Ca-phosphates, organic matter, iron oxides) inside soil aggregates were successfully identified and segmented. The advantages of this method over the common ROI imaging approach are presented. Finally, this method was used to compare different aggregates in a Cr-polluted soil and understand their possible pedological history. The present method can be used for the analysis of every type of SEM-EDX data cubes, allowing its application to different types of samples and fields of study.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Matthias Alfel
Altre libertà : pratiche performative e comportamentali nella poesia visuale italiana degli anni Sessanta e Settanta
No full textIl saggio a più mani (Zanchetti, Colombo, Giuranna, Sem) indaga e legge le esperienze di azione poetica e di performance sviluppate dalle neoavanguardie verbovisuali italiane degli anni Sessanta e Settanta a partire da una riformulazione delle parole in libertà futuriste.
In particolare si mettono in luce le esperienze propriamente performative di poeti e artisti quali Balestrini, Caruso, Costa, Xerra, Sarenco, Niccolai, Oberto, Parmiggiani, Vicinelli e di poeti come Chiari, Marchetti e Mosconi nei loro rapporti con il contesto internazionale di Fluxus. Da non dimenticare anche figure come La Rocca, Vaccari e Patella, anche per la loro produzione filmica.
Il saggio si sofferma poi su alcune figure specifiche: Arrigo Lora-Totino, Adriano Spatola, Eugenio Miccini, Maurizio Nannucci ed Emilio Villa.
L’ultima parte del saggio – Emilio Villa: “par l’art sonore” – è stata scritta da Davide Colombo. Si tratta di un approfondimento sul poeta e critico d’arte Emilio Villa: per Villa l’operazione poetica è un’azione sul verbum che conduce a una nuova e originaria percezione del phonos. Il saggio analizza la sperimentazione linguistica di Villa sia nei testi poetici sia nei testi dedicati agli artisti negli anni Cinquanta e Sessanta. In particolare si analizza come il tema del fonema venga sviluppato fino a sperimentazioni performative di poesia sonora durante gli anni Settanta.Many word-image experiments in late XXth Century art take their starting point from the historical precedent of the liberation of the poetic words pointed out by Marinetti in his manifesto Wireless Imagination and Words in Freedom (1913). The different practices in Italian visual poetry contributed to the very first development of conceptual art and performance art, going beyond the narrow limits of « sound-poetry » and « action-poetry » in strict sense. The authors of this essay, coordinated by G. Zanchetti, focus on some actions by a small number of artists and poets who played a key role in this field of expression in the Sixties and the Seventies: Martino Oberto, Ketty La Rocca, Franco Vaccari, Luca Patella, Adriano Spatola, Eugenio Miccini and Maurizio Nannucci. Two sections of the article are devoted to the work by Arrigo Lora-Totino as an author, editor and performer and to the inspirational and groundbreaking role of the poet Emilio Villa even in this kind of practices
Sensitivity of secondary electron yields and SEM images to scattering parameters in MC simulations
No full textIn the simulation of secondary electron yields (SEY) and secondary electron microscopy (SEM) images, there is always the question: are we using the correct scattering cross-sections?. The three scattering processes of interest are quasi-elastic phonon scattering, elastic Mott scattering and inelastic scattering using the dielectric function model. We have artificially scaled the scattering cross-sections, such that the probability for events associated with a particular model is either increased or decreased. The influence of this adjustment on the calculated SEYs and simulated SEM images is then evaluated. At first we have investigated the influence on the calculated SEY of pure and infinitely thick silicon. We have observed that the influence of the acoustic phonon scattering cross-sections is seen all the way up to the incident primary electron energy of 10 keV. We have extended the analysis to the simulation of SEM images of three dimensional rough lines of PMMA located on a silicon substrate. We conclude that the scaling of the scattering cross-sections affects the contrast of the SEM images, but not the roughness characterization of the lines, i.e. the 3σ of the line edge roughness (LER), correlation length and roughness exponent.Accepted Author ManuscriptImPhys/Charged Particle Optic
Cleanroom in an SEM
No full textThe work described in the doctoral thesis aims to enhance the functionality of a scanning electron microscope (SEM) by integrating miniaturized versions of cleanroom tools used in microfabrication. The thesis presents the integration of substrate heating, in-situ thermal atomic layer deposition (ALD), sputtering, and thermal evaporation within the SEM. These techniques are expected to enable fast and efficient fabrication of proof-of-concept devices with minimal resources. The thesis also discusses the challenges, limitations, and future work of the integrated cleanroom processes in SEM.ImPhys/Hagen grou
Author-suggested reviewers are more likely to give favorable scores.
No full textThe point is the mean and the error bars are the standard errors of the mean (SEM). For comparison across means, the asterisk indicates the statistical significance of a two-sample t test where "***", "**", and "*" represent p p p < 0.1, respectively.</p
Estimating Step Heights from Top-Down SEM Images
No full textScanning electron microscopy (SEM) is one of the most common inspection methods in the semiconductor industry and in research labs. To extract the height of structures using SEM images, various techniques have been used, such as tilting a sample, or modifying the SEM tool with extra sources and/or detectors. However, none of these techniques focused on extraction of height information directly from top-down images. In this work, using Monte Carlo simulations, we studied the relation between step height and the emission of secondary electrons (SEs) resulting from exposure with primary electrons at different energies. It is found that part of the SE signal, when scanning over a step edge, is determined by the step height rather than the geometry of the step edge. We present a way to quantify this, arriving at a method to determine the height of structures from top-down SEM images. The method is demonstrated on three different samples using two different SEM tools, and atomic force microscopy is used to measure the step height of the samples. The results obtained are in qualitative agreement with the results from the Monte Carlo simulations.ImPhys/Charged Particle Optic
Author-suggested reviewers produce reviewers that are judged as lower quality by editors.
No full textThe point is the mean and the error bars are the standard errors of the mean (SEM). For comparison across means, the asterisk indicates the statistical significance of a two-sample t test where "***", "**", and "*" represent p p p < 0.1, respectively.</p
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