Implementation and Evaluation of Novel Buildstyles in Fused Deposition Modeling (FDM)

Previous investigations have shown that the optimization of extrusion dynamics in .conjunction with the buildstyle pattern is of paramount importance to increase part quality in Fused Deposition Modeling (FDM). Recently domain decomposition and space filling curves have been introduced for slice generation in FDM [1]. The current work focuses on the implementations of fractal-like buildstyle .patterns using. Simulated Annealing [2, 3], Lin-Kernighan algorithms [4] and Construction Procedures based on Nearest Neighbor Heuristics [5]. These computational optimization procedures are able to generate filling patterns that allow the continuous deposition of a single road to fill arbitrary shaped domains. The necessary software modules to produce arbitrary threedimensional artifacts have been developed and are evaluated with respect to part quality and build time.Mechanical Engineerin

Application of the "risk of ambulatory disability" (RoAD) score in a "real-world" single-center multiple sclerosis cohort.

Survival analysis of reaching EDSS ≥4.0 based on RoAD score ≥4 (dashed line) and <4 (solid line) by Cox regression analysis. (A) Unadjusted regression analysis. (B) Regression controlled for sex and immunotherapy groups, and the trajectory of treatment changes during follow-up

Reliable brain morphometry from contrast-enhanced T1w-MRI in patients with multiple sclerosis.

Brain morphometry is usually based on non-enhanced (pre-contrast) T1-weighted MRI. However, such dedicated protocols are sometimes missing in clinical examinations. Instead, an image with a contrast agent is often available. Existing tools such as FreeSurfer yield unreliable results when applied to contrast-enhanced (CE) images. Consequently, these acquisitions are excluded from retrospective morphometry studies, which reduces the sample size. We hypothesize that deep learning (DL)-based morphometry methods can extract morphometric measures also from contrast-enhanced MRI. We have extended DL+DiReCT to cope with contrast-enhanced MRI. Training data for our DL-based model were enriched with non-enhanced and CE image pairs from the same session. The segmentations were derived with FreeSurfer from the non-enhanced image and used as ground truth for the coregistered CE image. A longitudinal dataset of patients with multiple sclerosis (MS), comprising relapsing remitting (RRMS) and primary progressive (PPMS) subgroups, was used for the evaluation. Global and regional cortical thickness derived from non-enhanced and CE images were contrasted to results from FreeSurfer. Correlation coefficients of global mean cortical thickness between non-enhanced and CE images were significantly larger with DL+DiReCT (r = 0.92) than with FreeSurfer (r = 0.75). When comparing the longitudinal atrophy rates between the two MS subgroups, the effect sizes between PPMS and RRMS were higher with DL+DiReCT both for non-enhanced (d = -0.304) and CE images (d = -0.169) than for FreeSurfer (non-enhanced d = -0.111, CE d = 0.085). In conclusion, brain morphometry can be derived reliably from contrast-enhanced MRI using DL-based morphometry tools, making additional cases available for analysis and potential future diagnostic morphometry tools

The Keck Cosmic Web Imager: a capable new integral field spectrograph for the W. M. Keck Observatory

The Keck Cosmic Web Imager (KCWI) is a new facility instrument being developed for the W. M. Keck Observatory and funded for construction by the Telescope System Instrumentation Program (TSIP) of the National Science Foundation (NSF). KCWI is a bench-mounted spectrograph for the Keck II right Nasmyth focal station, providing integral field spectroscopy over a seeing-limited field up to 20"x33" in extent. Selectable Volume Phase Holographic (VPH) gratings provide high efficiency and spectral resolution in the range of 1000 to 20000. The dual-beam design of KCWI passed a Preliminary Design Review in summer 2011. The detailed design of the KCWI blue channel (350 to 700 nm) is now nearly complete, with the red channel (530 to 1050 nm) planned for a phased implementation contingent upon additional funding. KCWI builds on the experience of the Caltech team in implementing the Cosmic Web Imager (CWI), in operation since 2009 at Palomar Observatory. KCWI adds considerable flexibility to the CWI design, and will take full advantage of the excellent seeing and dark sky above Mauna Kea with a selectable nod-and-shuffle observing mode. In this paper, models of the expected KCWI sensitivity and background subtraction capability are presented, along with a detailed description of the instrument design. The KCWI team is lead by Caltech (project management, design and implementation) in partnership with the University of California at Santa Cruz (camera optical and mechanical design) and the W. M. Keck Observatory (program oversight and observatory interfaces)

Dissertatio Inavgvralis Ivridica De Concvrsv Cedentis Et Cessionarii, Secvndvm Diversa Ivris Romani Principia, Et Vsvm Hodiernvm Forensem

Gießen, Univ., Jur. Diss., 1750Qvam Praeside Deo Immortali Ex Decreto Illvstris Ivrisconsvltorvm Ordinis In Academia Lvdoviciana Pro Licentia Svmmos in Vtroquve Ivre Honores Et Privilegia Doctoralia Rite Capessendi Ad Diem Avg. MDCCL. Publicae Ervditorvm Censvrae Exhibet Ioannes Christophorvs Pistor GiessensisEnth. 5 Gedichte der BeiträgerVorlageform des Erscheinungsvermerks: Giessae, Typis Ioannis Iacobi Bravn, Acad. Typogr

Thermo-mechanical Analysis of Parts Fabricated via Fused Deposition Modeling (FDM)

The quality of Fused Deposition Modeling parts that are built using the standard parallel road approach depends significantly on the orientation of the slices. In this study the expansion coefficient, tensile strength and elastic. modulus of FDM parts made from ABS were determined experimentally. The parts were built using the standard toolpath (parallel roads) with a uni directional stacking sequence. The results were used to determine the thermo-mechanical properties for an.individual slice. Classical lamination theory was applied to predict properties and stiffness of matrix parts with arbitrarily oriented stacking sequences. The results of these predictions are compared with experimental results for a quasi-isotropic stacking sequence.Mechanical Engineerin

Basic Mechanism of Surface Topography Evolution in Electron Beam Based Additive Manufacturing

This study introduces and verifies a basic mechanism of surface topography evolution in electron beam additive manufacturing (E-PBF). A semi-analytical heat conduction model is used to examine the spatio-temporal evolution of the meltpool and segment the build surface according to the emerging persistent meltpool domains. Each persistent domain is directly compared with the corresponding melt surface, and exhibits a characteristic surface morphology and topography. The proposed underlying mechanism of topography evolution is based on different forms of material transport in each distinct persistent domain, driven by evaporation and thermocapillary convection along the temperature gradient of the emerging meltpool. This effect is shown to be responsible for the upper bound of the standard process window in E-PBF, where surface bulges form. Based on this mechanism, process strategies to prevent the formation of surface bulges for complex geometries are proposed