Mixed Reality-based Process Control of Automatic Printed Circuit Board Assembly Lines

A mixed reality (MR)-based concept for supporting and optimizing the way operators work with automatic printed circuit board (PCB) assembly lines, is proposed. In order to enhance the work process’ interface, users are outfitted with a head-mounted display (HMD), so they can both actively access process relevant machine data and passively receive system notifications in a heads-up display (HUD), instead of having to manually query the terminal of the machine of interest at its very location. This approach was implemented and tested in a field study with one of the assembly lines of an electronics manufacturing services (EMS)-company. 30 staff members were recruited as test subjects and 90% of them appreciated the system deployment, due to its noticeable additional benefits compared to the status quo

Augmented reality-based training of the PCB assembly process

In this paper we propose an augmented reality (AR) based assistance system for reliably teaching the assembly process of printed circuit boards (PCB) to workers by using a smart glass running a self-developed software. The system is operated freehand by looking at QR-Codes and highlights a component’s retrieval location and installation point in the user’s field of vision by using four markers. A study executed in a production line of an Electronics Manufacturing Services (EMS)- company resulted in an errorless performance of each individual participant who was equipped with the system. This paper describes the related work, concept and implementation of the software as well as the conducted study and its results. Finally a conclusion summarizes the success of the system and hints at future work

Site symmetry and crystal symmetry: a spherical tensor analysis

The relation between the properties of a specific crystallographic site and the properties of the full crystal is discussed by using spherical tensors. The concept of spherical tensors is introduced and the way it transforms under the symmetry operations of the site and from site to site is described in detail. The law of spherical tensor coupling is given and illustrated with the example of the electric dipole and quadrupole transitions in x-ray absorption spectroscopy. The main application of the formalism is the reduction of computation time in the calculation of the properties of crystals by band structure methods. The general approach is illustrated by the examples of substitutional chromium in spinel and substitutional vanadium in garnet.Comment: 27 pages, 3 figure

Large characteristic lengths in 3D chiral elastic metamaterials

Three-dimensional (3D) chiral mechanical metamaterials enable behaviors not accessible in ordinary materials. In particular, a coupling between displacements and rotations can occur, which is symmetry-forbidden without chirality. In this work, we solve three open challenges of chiral metamaterials. First, we provide a simple analytical model, which we use to rationalize the design of the chiral characteristic length. Second, using rapid multi-photon multi-focus 3D laser microprinting, we manufacture samples with more than 105 micrometer-sized 3D chiral unit cells. This number surpasses previous work by more than two orders of magnitude. Third, using analytical and numerical modeling, we realize chiral characteristic lengths of the order of ten unit cells, changing the sample-size dependence qualitatively and quantitatively. In the small-sample limit, the twist per axial strain is initially proportional to the sample side length, reaching a maximum at the characteristic length. In the thermodynamic limit, the twist per axial strain is proportional to the square of the characteristic length. We show that chiral micropolar continuum elasticity can reproduce this behavior

Selection and optimization of a suitable pretreatment method for miscanthus and poplar raw material

Miscanthus and poplar are very promising second‐generation feedstocks due to the high growth rates and low nutrient demand. The aim of the study was to develop a systematic approach for choosing suitable pretreatment methods evaluated with the modified severity factor (log R$^{"}$$_{o}$). Optimal pretreatment results in a high delignification grade, low cellulose solubilization and increased accessibility for enzymatic hydrolysis while revealing minimal log R$^{"}$$_{o}$ values. In order to do so, several reaction approaches were compared. Acid‐catalyzed organosolv processing carried out for miscanthus and poplar revealed the highest delignification grade leading to a relatively high glucose yield after enzymatic saccharification. In both cases, a design of experiments approach was used to study the influence of relevant parameters. Modeling the data resulted in the identification of optimum pretreatment conditions for miscanthus with concentrations of 0.16% H$_{2}$SO$_{4}$ and 50% EtOH at 185°C for a retention time of 60 min. Experimental validation of these conditions revealed an even higher delignification degree (88%) and glucose yield (85%) than predicted. 0.19% H$_{2}$SO$_{4}$ and 50% EtOH were determined as optimum concentrations, 182°C and 48 min identified as optimum pretreatment conditions for poplar; the delignification degree was 84% and the resulting glucose yield 70%

Multiparameter RNA and Codon Optimization: A Standardized Tool to Assess and Enhance Autologous Mammalian Gene Expression

Autologous expression of recombinant human proteins in human cells for biomedical research and product development is often hampered by low expression yields limiting subsequent structural and functional analyses. Following RNA and codon optimization, 50 candidate genes representing five classes of human proteins – transcription factors, ribosomal and polymerase subunits, protein kinases, membrane proteins and immunomodulators – all showed reliable, and 86% even elevated expression. Analysis of three representative examples showed no detrimental effect on protein solubility while unaltered functionality was demonstrated for JNK1, JNK3 and CDC2 using optimized constructs. Molecular analysis of a sequence-optimized transgene revealed positive effects at transcriptional, translational, and mRNA stability levels. Since improved expression was consistent in HEK293T, CHO and insect cells, it was not restricted to distinct mammalian cell systems. Additionally, optimized genes represent powerful tools in functional genomics, as demonstrated by the successful rescue of an siRNA-mediated knockdown using a sequence-optimized counterpart. This is the first large-scale study addressing the influence of multiparameter optimization on autologous human protein expression

Electrooxidation of formic acid on gold : An ATR-SEIRAS study of the role of adsorbed formate

Funding from the DGI (Spanish Ministry of Education and Science) through Projects CTQ2009-07017 and PLE2009-0008 is gratefully acknowledged. M.E.-E. acknowledges an FPI fellowship from the Spanish Ministry of Science and Innovation and an accommodation grant at the Residencia de Estudiantes from the Madrid City Council. C. V.-D. acknowledges a JAE-Doc fellowship from CSIC.Peer reviewedPostprin

Characterization of the manganese sites in manganese redox enzymes: Catalase and superoxide dismutase.

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30701/1/0000346.pd