Utjecaj nečistoća na otpor električnih kontakata

Influence of surface cleaning methods on contact materials as well as on the contact resistance of stationary and sliding electrical contacts was investigated. Two cleaning methods were studied: cleaning with fluorochlorohydrogencarbon (FCHC) and low temperature cleaning in reductive plasma. Contact materials for professional electronics were investigated. Dependence of the contact resistance on contact force was measured. All measurements were performed with a computer controlled system, constructed and developed in our laboratory.Ispitivane su metode čišćenja površina kontaktnih materijala i kontaktni otpor mirnih i kliznih električnih priključaka za profesionalnu elektroniku. Proučavano je čišćenje fluoroklorougljikovodikom i niskotemperaturno čišćenje u reducirajućoj plazmi. Mjerena je ovisnost kontaktnog otpora o pritisku. Sva su mjerenja načinjena pomoću sustava vodenog računalom, razvijenog u našem laboratoriju

Utjecaj nečistoća na otpor električnih kontakata

Influence of surface cleaning methods on contact materials as well as on the contact resistance of stationary and sliding electrical contacts was investigated. Two cleaning methods were studied: cleaning with fluorochlorohydrogencarbon (FCHC) and low temperature cleaning in reductive plasma. Contact materials for professional electronics were investigated. Dependence of the contact resistance on contact force was measured. All measurements were performed with a computer controlled system, constructed and developed in our laboratory.Ispitivane su metode čišćenja površina kontaktnih materijala i kontaktni otpor mirnih i kliznih električnih priključaka za profesionalnu elektroniku. Proučavano je čišćenje fluoroklorougljikovodikom i niskotemperaturno čišćenje u reducirajućoj plazmi. Mjerena je ovisnost kontaktnog otpora o pritisku. Sva su mjerenja načinjena pomoću sustava vodenog računalom, razvijenog u našem laboratoriju

Vortex migration in protoplanetary disks

We consider the radial migration of vortices in two-dimensional isothermal gaseous disks. We find that a vortex core, orbiting at the local gas velocity, induces velocity perturbations that propagate away from the vortex as density waves. The resulting spiral wave pattern is reminiscent of an embedded planet. There are two main causes for asymmetries in these wakes: geometrical effects tend to favor the outer wave, while a radial vortensity gradient leads to an asymmetric vortex core, which favors the wave at the side that has the lowest density. In the case of asymmetric waves, which we always find except for a disk of constant pressure, there is a net exchange of angular momentum between the vortex and the surrounding disk, which leads to orbital migration of the vortex. Numerical hydrodynamical simulations show that this migration can be very rapid, on a time scale of a few thousand orbits, for vortices with a size comparable to the scale height of the disk. We discuss the possible effects of vortex migration on planet formation scenarios.Comment: 13 pages, 13 figures, accepted for publication in Ap

Comparative Life Cycle Assessment Of Conventionally Manufactured And Additive Remanufactured Electric Bicycle Motors

In a circular economy, remanufacturing is crucial in reducing the use of primary raw materials and energy compared to new production. However, poor availability of non-standardized wear components can prevent remanufacturing. Additive manufacturing is a promising alternative to conventional manufacturing or spare part purchase for those wear components required for remanufacturing. However, there is uncertainty regarding the environmental impact of using additive manufacturing for remanufacturing. This paper compares conventional and additive spare parts manufacturing to evaluate the potential environmental savings of remanufacturing electric bicycle motors. Therefore, a reference motor was selected, and its manufacturing processes were modeled in SimaPro using the ecoinvent 3.8 Life Cycle Assessment database and the latest knowledge on processing and manufacturing processes. The results show that conventional production of electric bicycle motors has a climate warming potential of around 28 kg CO2-eq. Additive remanufacturing of electric bicycle motors at the end of their life cycle offers significant environmental savings potential. The extent of savings depends on the condition of the used electric bicycle motor and, accordingly, the number of components that need to be replaced. According to the IPCC method for the electric bicycle motor investigated, the study estimates that approximately 90.4 % savings potential can be achieved in terms of Global Warming Potential

Cold Sprayed Tungsten Armor for Tokamak First Wall

Harnessing nuclear fusion is a challenging task, in particular because of the demands put on the used materials. In tokamaks, future energy sources, the inner-most chambers are to be coated with dense coatings of W, or W-Cr-based alloys. So far, the attempts for such coatings formation by other methods failed due to oxidation, high porosity, insufficient adhesion, high specific surface, or even insufficient thickness below 10 mu m. Cold spraying seems a promising technology for the task. In our study, we demonstrate the first successful fabrication of thick pure W coatings. W-Cr and W-Cr-Ti coatings were further prepared without oxidation of the metals. All coatings exhibited high hardness levels, good interface quality with three tested substrates and, importantly, a promising potential for formation of stable Cr2WOx phases

What’s the Meaning of Superhuman Performance in Today’s NLU?

In the last five years, there has been a significant focus in Natural Language Processing (NLP) on developing larger Pretrained Language Models (PLMs) and introducing benchmarks such as SuperGLUE and SQuAD to measure their abilities in language understanding, reasoning, and reading comprehension. These PLMs have achieved impressive results on these benchmarks, even surpassing human performance in some cases. This has led to claims of superhuman capabilities and the provocative idea that certain tasks have been solved. In this position paper, we take a critical look at these claims and ask whether PLMs truly have superhuman abilities and what the current benchmarks are really evaluating. We show that these benchmarks have serious limitations affecting the comparison between humans and PLMs and provide recommendations for fairer and more transparent benchmarks.</p

Meditation and Cardiovascular Health: What is the Link?

Meditation as a form of body–mind interaction for primary and secondary prevention in cardiovascular disease has been discussed critically in the past. However, data that aimed to link this intervention to a reduction of various aspects of cardiovascular disease, rendering it a potential part of a cost-effective treatment approach in patients at risk, remain scarce and inconclusive. This article aims to provide an overview of currently available evidence in the literature and the potential impact of meditation on cardiovascular health. However, the data highlighted in this article cannot render with certainty directly reproducible effects of meditation on patients’ cardiovascular disease profiles. Meditation may be suggested only as an additional link in the chain of primary and secondary prevention until future research provides sufficient data on this topic

Validation of Novel Molecular Imaging Targets Identified by Functional Genomic mRNA Profiling to Detect Dysplasia in Barrett’s Esophagus

SIMPLE SUMMARY: Barrett’s esophagus (BE) is the precursor of esophageal adenocarcinoma (EAC). Dysplastic BE (DBE), including low-grade dysplasia (LGD) and high-grade dysplasia (HGD), shows a higher progression risk to EAC compared to non-dysplastic BE (NDBE). If LGD or HGD is detected, more intensive endoscopic surveillance or endoscopic treatment is recommended. This results in a significantly improved prognosis compared to EACs treated by surgery and/or chemoradiotherapy. However, the miss rates for detecting DBE by endoscopy remain high. Fluorescence molecular endoscopy (FME) can fill this gap by targeting the tumor-specific expression of proteins. This study aimed to identify target proteins suitable for FME. We identified SPARC, SULF1, PKCι, and DDR1 as promising imaging targets for FME to differentiate DBE from NDBE tissue. We are also the first to develop near-infrared fluorescent tracers, SULF1-800CW and SPARC-800CW, for the endoscopic imaging of DBE tissue. ABSTRACT: Barrett’s esophagus (BE) is the precursor of esophageal adenocarcinoma (EAC). Dysplastic BE (DBE) has a higher progression risk to EAC compared to non-dysplastic BE (NDBE). However, the miss rates for the endoscopic detection of DBE remain high. Fluorescence molecular endoscopy (FME) can detect DBE and mucosal EAC by highlighting the tumor-specific expression of proteins. This study aimed to identify target proteins suitable for FME. Publicly available RNA expression profiles of EAC and NDBE were corrected by functional genomic mRNA (FGmRNA) profiling. Following a class comparison between FGmRNA profiles of EAC and NDBE, predicted, significantly upregulated genes in EAC were prioritized by a literature search. Protein expression of prioritized genes was validated by immunohistochemistry (IHC) on DBE and NDBE tissues. Near-infrared fluorescent tracers targeting the proteins were developed and evaluated ex vivo on fresh human specimens. In total, 1976 overexpressed genes were identified in EAC (n = 64) compared to NDBE (n = 66) at RNA level. Prioritization and IHC validation revealed SPARC, SULF1, PKCι, and DDR1 (all p < 0.0001) as the most attractive imaging protein targets for DBE detection. Newly developed tracers SULF1-800CW and SPARC-800CW both showed higher fluorescence intensity in DBE tissue compared to paired non-dysplastic tissue. This study identified SPARC, SULF1, PKCι, and DDR1 as promising targets for FME to differentiate DBE from NDBE tissue, for which SULF1-800CW and SPARC-800CW were successfully ex vivo evaluated. Clinical studies should further validate these findings