1,141 research outputs found
Design Principles for Leveraging Sustainability in Business Modelling Tools
Sustainability has become increasingly important to business research and practice. Approaches that support fundamental changes in behaviour to act economically, ecologically and socially are required. Modelling and analysing business models can contribute to this, for example by generating new ideas and enabling innovation as well as improving and evaluating current businesses. Although, the interest in business model innovation is booming, and software tools for business model development hold great promise for supporting business model innovation, there is only limited support and guidance for a tool-support that enables a satisfactory consideration of sustainability. Furthermore, there is currently a lack of comprehensive knowledge concerning which features can contribute to this consideration, and how they can be implemented. In this article, we report on the results of design science research (DSR) study that develops a set of design principles for reflecting sustainability in business models, which are refined and evaluated in several cycles. Our findings can support practitioners in (re-)designing tools, selecting and innovating business models, and—for researchers—can serve as a step towards more advances theories regarding software tools for sustainability in business modelling as well as for creating new business model ideas
Functionality Investigations of Dry-Lubricated Molybdenum Trioxide Cylindrical Roller Thrust Bearings
In addition to using conventional lubricants, such as oil and grease, rolling bearings can also be used with a dry lubricant. For example, the use of dry lubricant systems is necessary when the application of oils or greases is not possible (e.g., at high temperatures or in aerospace applications). The requirements of a solid lubricant are to reduce friction and wear of mechanical contact partners. In this work, a molybdenum-based coating system was applied by means of physical vapor deposition (PVD). The coating system consists of a molybdenum (Mo) reservoir with molybdenum trioxide (MoO3) as the top layer. The MoO3, which is particularly important for the run-in and the lubricating effect, is intended to continuously regenerate from the reservoir via tribo-oxidation. To determine the friction and wear behavior, cylindrical roller thrust bearings were used. Experiments demonstrated that the lubrication system is effective and that the frictional behavior has been improved. On the one hand, the frictional torque of the rolling bearings has been considerably reduced and, on the other, significantly extended operating times have been determined compared to unlubricated reference experiments. Simultaneously, material analyses have been carried out by means of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The investigations showed that the MoO3 was transferred to uncoated bearing components. This improved the tribological behavior and reduced abrasive and adhesive wear
Sequelae of premature birth in young adults
Background and Purpose
Qualitative studies about the abnormalities appreciated on routine magnetic resonance imaging (MRI) sequences in prematurely born adults are lacking. This article aimed at filling this knowledge gap by (1) qualitatively describing routine imaging findings in prematurely born adults, (2) evaluating measures for routine image interpretation and (3) investigating the impact of perinatal variables related to premature birth.
Methods
In this study two board-certified radiologists assessed T1-weighted and FLAIR-weighted images of 100 prematurely born adults born very preterm (VP <32 weeks) and/or at very low birth weight (VLBW <1500 g) and 106 controls born at full term (FT) (mean age 26.8 ± 0.7 years). The number of white matter lesions (WML) was counted according to localization. Lateral ventricle volume (LVV) was evaluated subjectively and by measurements of Evans’ index (EI) and frontal-occipital-horn ratio (FOHR). Freesurfer-based volumetry served as reference standard. Miscellaneous incidental findings were noted as free text.
Results
The LVV was increased in 24.7% of VP/VLBW individuals and significantly larger than in FT controls. This was best identified by measurement of FOHR (AUC = 0.928). Ventricular enlargement was predicted by low gestational age (odds ratio: 0.71, 95% CI 0.51–0.98) and presence of neonatal intracranial hemorrhage (odds ratio: 0.26, 95% CI 0.07–0.92). The numbers of deep and periventricular WML were increased while subcortical WMLs were not.
Conclusion
Enlargement of the LVV and deep and periventricular WMLs are typical sequelae of premature birth that can be appreciated on routine brain MRI. To increase sensitivity of abnormal LVV detection, measurement of FOHR seems feasible in clinical practice
Investigation of the Hardness Development of Molybdenum Coatings under Thermal and Tribological Loading
The increasing global demand for innovative and environmentally friendly lubricants can be met through the use of solid lubricants. By switching from conventional lubricants such as various oils or grease to solid lubricants, new scopes of application can also be opened up. The main requirements for solid lubricants are a reduction in the coefficient of friction (CoF) and an increase in wear resistance. Due to the favourable material properties, molybdenum (Mo) coatings fulfil the tribological requirements and are therefore promising solid lubricants which can be applied via physical vapour deposition (PVD). In this work, the impact of substrate temperature on the hot hardness of deposited Mo coatings was determined. The specimen with the highest hot hardness was then tribologically examined both at the micro and nano level. Through an analysis of the wear tracks by means of nanoindentation and scanning electron microscopy (SEM), it was possible to detect the influence of the tribological load separately from that of the thermal loads. The results showed that the tribological load influenced the Mo coating by significantly increasing its hardness. This was achieved due to the work hardening of the Mo layer leading to an increase in the wear resistance of the coating
A Comparison of Two Shallow Water Models with Non-Conforming Adaptive Grids: classical tests
In an effort to study the applicability of adaptive mesh refinement (AMR)
techniques to atmospheric models an interpolation-based spectral element
shallow water model on a cubed-sphere grid is compared to a block-structured
finite volume method in latitude-longitude geometry. Both models utilize a
non-conforming adaptation approach which doubles the resolution at fine-coarse
mesh interfaces. The underlying AMR libraries are quad-tree based and ensure
that neighboring regions can only differ by one refinement level.
The models are compared via selected test cases from a standard test suite
for the shallow water equations. They include the advection of a cosine bell, a
steady-state geostrophic flow, a flow over an idealized mountain and a
Rossby-Haurwitz wave. Both static and dynamics adaptations are evaluated which
reveal the strengths and weaknesses of the AMR techniques. Overall, the AMR
simulations show that both models successfully place static and dynamic
adaptations in local regions without requiring a fine grid in the global
domain. The adaptive grids reliably track features of interests without visible
distortions or noise at mesh interfaces. Simple threshold adaptation criteria
for the geopotential height and the relative vorticity are assessed.Comment: 25 pages, 11 figures, preprin
Personal Dosimetry in Pulsed Photon Fields with the Dosepix Detector
First investigations regarding dosimetric properties of the hybrid,
pixelated, photon-counting Dosepix detector in a pulsed photon field (RQR8) for
the personal dose equivalent are presented. The influence
quantities such as pulse duration and dose rate were varied, and their
responses were compared to the legal limits provided in PTB-A 23.2. The
variation of pulse duration at a nearly constant dose rate of 3.7Sv/h shows
a flat response around 1.0 from 3.6s down to 2ms. A response close to
1.0 is achieved for dose rates from 0.07mSv/h to 35Sv/h for both pixel
sizes. Above this dose rate, the large pixels (220m edge
length) are below the lower limit. The small pixels (55m edge
length) stay within limits up to 704Sv/h. The count rate linearity is
compared to previous results, confirming the saturating count rate for high
dose rates.Comment: 6 pages, 3 figures. This work has been submitted to the IEEE for
possible publication. Copyright may be transferred without notice, after
which this version may no longer be accessibl
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Assessment of interactions between 205 breast cancer susceptibility loci and 13 established risk factors in relation to breast cancer risk, in the Breast Cancer Association Consortium.
BACKGROUND: Previous gene-environment interaction studies of breast cancer risk have provided sparse evidence of interactions. Using the largest available dataset to date, we performed a comprehensive assessment of potential effect modification of 205 common susceptibility variants by 13 established breast cancer risk factors, including replication of previously reported interactions. METHODS: Analyses were performed using 28 176 cases and 32 209 controls genotyped with iCOGS array and 44 109 cases and 48 145 controls genotyped using OncoArray from the Breast Cancer Association Consortium (BCAC). Gene-environment interactions were assessed using unconditional logistic regression and likelihood ratio tests for breast cancer risk overall and by estrogen-receptor (ER) status. Bayesian false discovery probability was used to assess the noteworthiness of the meta-analysed array-specific interactions. RESULTS: Noteworthy evidence of interaction at ≤1% prior probability was observed for three single nucleotide polymorphism (SNP)-risk factor pairs. SNP rs4442975 was associated with a greater reduction of risk of ER-positive breast cancer [odds ratio (OR)int = 0.85 (0.78-0.93), Pint = 2.8 x 10-4] and overall breast cancer [ORint = 0.85 (0.78-0.92), Pint = 7.4 x 10-5) in current users of estrogen-progesterone therapy compared with non-users. This finding was supported by replication using OncoArray data of the previously reported interaction between rs13387042 (r2 = 0.93 with rs4442975) and current estrogen-progesterone therapy for overall disease (Pint = 0.004). The two other interactions suggested stronger associations between SNP rs6596100 and ER-negative breast cancer with increasing parity and younger age at first birth. CONCLUSIONS: Overall, our study does not suggest strong effect modification of common breast cancer susceptibility variants by established risk factors
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