695 research outputs found
Determination of measurement uncertainty by Monte Carlo simulation
Modern coordinate measurement machines (CMM) are universal tools to measure
geometric features of complex three-dimensional workpieces. To use them as
reliable means of quality control, the suitability of the device for the
specific measurement task has to be proven. Therefore, the ISO 14253 standard
requires, knowledge of the measurement uncertainty and, that it is in
reasonable relation with the specified tolerances. Hence, the determination of
the measurement uncertainty, which is a complex and also costly task, is of
utmost importance. The measurement uncertainty is usually influenced by several
contributions of various sources. Among those of the machine itself, e.g.,
guideway errors and the influence of the probe and styli play an important
role. Furthermore, several properties of the workpiece, such as its form
deviations and surface roughness, have to be considered. Also the environmental
conditions, i.e., temperature and its gradients, pressure, relative humidity
and others contribute to the overall measurement uncertainty. Currently, there
are different approaches to determine task-specific measurement uncertainties.
This work reports on recent advancements extending the well-established method
of PTB's Virtual Coordinate Measuring Machine (VCMM) to suit present-day needs
in industrial applications. The VCMM utilizes numerical simulations to
determine the task-specific measurement uncertainty incorporating broad
knowledge about the contributions of, e.g., the used CMM, the environment and
the workpiece
Scientific Approaches and Methodology to Determine the Value of Data as an Asset and Use Case in the Automotive Industry
From a theoretical perspective data does not constitute a traditional business asset. Existing valuation approaches are either sector specific or still unexplored. In modern businesses the value-adding use and monetization of existing âbig dataâ represents one of the greatest potentials in the context of digital transformation. This paper aims at reviewing methods and developing an integrated methodology for the value determination of data in general and for use in the manufacturing industry in particular. Therefore, the general state of research in data value assessment is investigated by a broad literature analysis. Based on the identified general principles, methodological requirements for data value determination are compiled. A new methodology for data evaluation is developed and applied to four use cases coming from the automotive industry. The results show that the methodology can be used in different contexts and thus enables managers to explore the most promising use cases for data-driven business
What Users Think about the Differences between Caffeine and Illicit/Prescription Stimulants for Cognitive Enhancement
Pharmacological cognitive enhancement (CE) is a topic of increasing public awareness. In the scientific literature on student use of CE as a study aid for academic performance enhancement, there are high prevalence rates regarding the use of caffeinated substances (coffee, caffeinated drinks, caffeine tablets) but remarkably lower prevalence rates regarding the use of illicit/prescription stimulants such as amphetamines or methylphenidate. While the literature considers the reasons and mechanisms for these different prevalence rates from a theoretical standpoint, it lacks empirical data to account for healthy students who use both, caffeine and illicit/prescription stimulants, exclusively for the purpose of CE. Therefore, we extensively interviewed a sample of 18 healthy university students reporting non-medical use of caffeine as well as illicit/prescription stimulants for the purpose of CE in a face-to-face setting about their opinions regarding differences in general and morally-relevant differences between caffeine and stimulant use for CE. 44% of all participants answered that there is a general difference between the use of caffeine and illicit/prescription stimulants for CE, 28% did not differentiate, 28% could not decide. Furthermore, 39% stated that there is a moral difference, 56% answered that there is no moral difference and one participant was not able to comment on moral aspects. Participants came to their judgements by applying three dimensions: medical, ethical and legal. Weighing the medical, ethical and legal aspects corresponded to the students' individual preferences of substances used for CE. However, their views only partly depicted evidence-based medical aspects and the ethical issues involved. This result shows the need for well-directed and differentiated information to prevent the potentially harmful use of illicit or prescription stimulants for CE
A reservoir trap for antiprotons
We have developed techniques to extract arbitrary fractions of antiprotons
from an accumulated reservoir, and to inject them into a Penning-trap system
for high-precision measurements. In our trap-system antiproton storage times >
1.08 years are estimated. The device is fail-safe against power-cuts of up to
10 hours. This makes our planned comparisons of the fundamental properties of
protons and antiprotons independent from accelerator cycles, and will enable us
to perform experiments during long accelerator shutdown periods when background
magnetic noise is low. The demonstrated scheme has the potential to be applied
in many other precision Penning trap experiments dealing with exotic particles.Comment: Article by the BASE-collaboration at CERN. Results from the
Antiproton physics run 2014. Submitted to International Journal of Mass
Spectrometry, 8th of April 201
Unusual infections: Femoral abscess due to Nocardia abscessus in a patient suffering from metastatic peripheral bronchial carcinoma and hygienic consequences
During the course of a peripheral bronchial carcinoma with pulmonary and cerebral metastases a femoral abscess developed in a 49 year-old patient after radio- and chemotherapy. A bacterial strain, which was isolated four times from a deep wound of the left thigh was tentatively identified as a member of the genus Nocardia on the basis of selected phenotypic and chemotaxonomic characteristics. The isolate was confirmed to belong to Nocardia abscessus by 16S rRNA gene sequencing. This species had previously been described as the causative agent of soft tissue infections. Although rare, nocardia soft tissue infections as complication of systemic nocardiosis are typical air born infections of immuncompromised patients and need specific attention. Infection prevention can be realized by restriction of soil and aerosol (builder's dust) together with antibiotic intervention (oral administration of trimethoprim/sulfamethoxazole)
Environmental Effects on Temperature Stress Resistance in the Tropical Butterfly Bicyclus Anynana
BACKGROUND: The ability to withstand thermal stress is considered to be of crucial importance for individual fitness and species' survival. Thus, organisms need to employ effective mechanisms to ensure survival under stressful thermal conditions, among which phenotypic plasticity is considered a particularly quick and effective one. METHODOLOGY/PRINCIPAL FINDINGS: In a series of experiments we here investigate phenotypic adjustment in temperature stress resistance following environmental manipulations in the butterfly Bicyclus anynana. Cooler compared to warmer acclimation temperatures generally increased cold but decreased heat stress resistance and vice versa. In contrast, short-time hardening responses revealed more complex patterns, with, e.g., cold stress resistance being highest at intermediate hardening temperatures. Adult food stress had a negative effect on heat but not on cold stress resistance. Additionally, larval feeding treatment showed interactive effects with adult feeding for heat but not for cold stress resistance, indicating that nitrogenous larval resources may set an upper limit to performance under heat stress. In contrast to expectations, cold resistance slightly increased during the first eight days of adult life. Light cycle had marginal effects on temperature stress resistance only, with cold resistance tending to be higher during daytime and thus active periods. CONCLUSIONS/SIGNIFICANCE: Our results highlight that temperature-induced plasticity provides an effective tool to quickly and strongly modulate temperature stress resistance, and that such responses are readily reversible. However, resistance traits are not only affected by ambient temperature, but also by, e.g., food availability and age, making their measurement challenging. The latter effects are largely underexplored and deserve more future attention. Owing to their magnitude, plastic responses in thermal tolerance should be incorporated into models trying to forecast effects of global change on extant biodiversity
Control of a tower crane by means of algorithmic differentiation
Deriving Euler-Lagrangian equations of motion for sophisticated mechanical systems symbolically often results in complex and large expressions. Based on algorithmic differentiation we present an alternative
to the direct implementation of this equations. The Lagrangian provides the starting point for deriving the equations of motion and not necessarily has to be given explicitly. Algorithms containing loops or other control structures will work as well. We will demonstrate the usage of this alternative differentiation method on the system of a tower crane. Experimental results will complete this proposal
Time Travel Gamification of Learning and Training: From Theoretical Concepts to Practical Applications
Gamification is considered the systematic anticipation and design of affective experiences. It is not erroneously reduced to the usage of game-typical elements in another context. The human experiences in focus are varying forms of virtual time travel. In a time travel exploratory game, players return virtually to the past for gaining insights and, possibly, finding artifacts bring back to the present time. This works well for environmental education studying, by way of illustration, the worldwide ocean warming over several decades. Time travel prevention games go even further. Players who visit the past get an opportunity to impact their fate. This works well in application areas such as crime prevention and industrial accident prevention. Dynamic time travel prevention games are a recently developed game type in which the past changes dynamically to support the playerâs chances of successfully completing the mission. The authors present original concepts and technologies and demonstrate running applications
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