Dry rotary swaging–approaches for lubricant free process design Böhmermann, Florian; Hasselbruch, Henning; Herrmann, Marius ...
International journal of precision engineering and manufacturing-green technology,
10/2015, Letnik:
2, Številka:
4
Journal Article
Odprti dostop
Rotary swaging is an incremental cold forming process and allows for the cost effective manufacture of cylindrical light weight components such as rods or hollow shafts. The process has a widespread ...use particularly in the automotive industry for example for the manufacture of axles and steering spindles. Besides the generation of desired geometries, rotary swaging offers the advantage of improved work piece material properties due to strain hardening and furthermore the generation of variable wall thicknesses for hollow shafts, and therefore an optimal use of material resources. Nowadays rotary swaging is carried out under the use of extensive amounts of lubricant. Main functions of the lubricant are the cooling of work piece and tools, washing out of wear particles from the forming zone and process lubrication in general. Before further processing, remaining lubricant mandatorily needs to be cleaned off the work piece, increasing the costs per unit significantly. Thus, an enhancement of rotary swaging towards a lubricant free process, i.e. a dry rotary swaging, is seen to be highly innovative, both under economic and ecological aspects. However, a lubricant free process design exhibits considerably modified frictional conditions, compared to a conventional process layout. This leads to changes in the power.
Body size, coupled with abundance and taxonomy, may help to understand the mechanisms shaping community structure. Since the body size of fish is closely related to their trophic niche, size ...diversity (based on individual body size) of fish communities may capture intraspecific variations in fish trophic niches that are not detected by species diversity. Thus, the relationship between size diversity and species diversity may help to integrate variation at both intraspecific and interspecific levels. We studied the relationship between species diversity and size diversity as a measure of the degree of overlap in size among species and thereby the potential overlap in niches in a community. We hypothesized that the relationship between size diversity and species would be different across the European continent due to different levels of size overlap in fish communities. The data were derived from samplings of fish communities using standardised benthic gill nets in 363 lakes. At the continental scale, size diversity increased with species diversity; at the ecoregion scale, the slope of the relation changed across the continent, with the greatest mismatch occurring in northern Europe where communities comprised only one or a few species, but each of which exhibited a great range in size. There was an increase in slope towards the south with significant relations for four out of six ecoregions. The steeper size diversity‐species diversity slope at lower latitudes is attributable to a lower overlap in fish size and thus likely to finer niche separation. Our results also suggest that size diversity is not a strong surrogate for species diversity in European lake fish communities. Thus, particularly in fish communities composed of few species, measuring size diversity may help to detect potential functional variation which may be neglected by measuring species diversity alone.
The formation of related polymer/TiO sub(2) nanocomposites is studied using two alternative synthetic procedures. The triflic acid anhydride-catalyzed twin-polymerization (TP) of ( mu ...sub(4)-oxido)-hexakis( mu -furan-2-m ethoxo)-octakis(furan-2-methoxo)-tetratitanium (1) and ( mu sub(4)-oxido)-hexakis( mu -thiophene -2-methoxo)-octakis(thiophene-2-methoxo)-tetratitanium (2), is studied in comparison to the simultaneous polymerization (SP) of titantetraisopropylate Ti(OiPr) sub(4) with the corresponding furan- or thiophenemethanol, furfuryl alcohol (FA) and thienyl alcohol (TA), respectively. Both the TP of 1 and 2 produces nanostructured polyFA/TiO sub(2) or polyTA/TiO sub(2) hybrid materials. Interpenetrating inorganic/organic composite materials can be synthesized by twin- polymerization of ( mu sub(4)-oxido)-hexakis ( mu -furfuryloxo)-octakis(furfuryloxo)-tetra-titanium and ( mu sub(4)-oxido)-hexakis( mu -thiophene -2-methoxo)-octakis(thiophene-2-methoxo)-tetratitanium. The TiO sub(2) domains of the composite materials are 2-4 nm in dimension and are homogeneously distributed.
Amino-bisphosphonates and statins inhibit the mevalonate pathway, and may exert anti-tumor effects. The Wnt inhibitor dickkopf-1 (DKK-1) promotes osteolytic bone lesions by inhibiting osteoblast ...functions and has been implicated as an adverse marker in multiple cancers. We assessed the effects of mevalonate pathway inhibition on DKK-1 expression in osteotropic breast cancer.
Regulation of DKK-1 by bisphosphonates and statins was assessed in human breast cancer cell lines, and the role of the mevalonate pathway and downstream targets was analyzed. Moreover, the potential of breast cancer cells to modulate osteoblastogenesis via DKK-1 was studied in mC2C12 cells. Clinical relevance was validated by analyzing DKK-1 expression in the tissue and serum of women with breast cancer exposed to bisphosphonates.
DKK-1 was highly expressed in receptor-negative breast cancer cell lines. Patients with receptor-negative tumors displayed elevated levels of DKK-1 at the tissue and serum level compared to healthy controls. Zoledronic acid and atorvastatin potently suppressed DKK-1 in vitro by inhibiting geranylgeranylation of CDC42 and Rho. Regulation of DKK-1 was strongest in osteolytic breast cancer cell lines with abundant DKK-1 expression. Suppression of DKK-1 inhibited the ability of breast cancer cells to block WNT3A-induced production of alkaline phosphates and bone-protective osteoprotegerin in preosteoblastic C2C12 cells. In line with the in vitro data, treatment of breast cancer patients with zoledronic acid decreased DKK-1 levels by a mean of 60% after 12 months of treatment.
DKK-1 is a novel target of the mevalonate pathway that is suppressed by zoledronic acid and atorvastatin in breast cancer.
This article describes the development and eventual closing down of the research lab for inter-disciplinary problems in musical acoustics (Forschungslabor für akustisch-musikalische Grenzprobleme) at ...the Technical Centre for Radio and Television Broadcasting (RFZ) in Berlin-Adlershof. It discusses the design and building of the Subharchord electronic synthesizer, and the situation of that device within the social, economic and aesthetic contexts of the GDR. The instrument is presented as well as the background of the idea of subharmony. Finally, some musical works produced with the Subharchord in the lab are discussed. (Author abstract)
Luminous blue variables (LBVs) are massive stars caught in a post-main sequence phase, during which they lose a significant amount of mass. Since, on one hand, it is thought that the majority of ...massive stars are close binaries that will interact during their lifetime, and on the other, the most dramatic example of an LBV, η Car, is a binary, it would be useful to find other binary LBVs. We present here interferometric observations of the LBV HR Car done with the AMBER and PIONIER instruments attached to ESO’s Very Large Telescope Interferometer (VLTI). Our observations, spanning two years, clearly reveal that HR Car is a binary star. It is not yet possible to fully constrain the orbit, and the orbital period may lie between a few years and several hundred years. We derive a radius for the primary in the system and possibly also resolve the companion. The luminosity ratio in the H-band between the two components is changing with time, going from about 6 to 9. We also tentatively detect the presence of some background flux which remained at the 2% level until January 2016, but then increased to 6% in April 2016. Our AMBER results show that the emission line-forming region of Brγ is more extended than the continuum-emitting region as seen by PIONIER and may indicate some wind-wind interaction. Most importantly, we constrain the total masses of both components, with the most likely range being 33.6 M⊙ and 45 M⊙. Our results show that the LBV HR Car is possibly an η Car analog binary system with smaller masses, with variable components, and further monitoring of this object is definitively called for.
ABSTRACT Eta Carinae's spectroscopic events (periastron passages) in 2003, 2009, and 2014 differed progressively. He ii λ4687 and nearby N ii multiplet 5 have special significance because they ...respond to very soft X-rays and the ionizing UV radiation field (EUV). Hubble Space Telescope (HST)/STIS observations in 2014 show dramatic increases in both features compared to the previous 2009.1 event. These results appear very consistent with a progressive decline in the primary wind density, proposed years ago on other grounds. If material falls onto the companion star near periastron, the accretion rate may now have become too low to suppress the EUV.
Ultra-hot giant exoplanets receive thousands of times Earth’s
insolation
1
,
2
. Their high-temperature
atmospheres (>2,000 K) are ideal laboratories for studying extreme
planetary climates and ...chemistry
3
–
5
. Daysides
are predicted to be cloud-free, dominated by atomic species
6
and substantially hotter than
nightsides
5
,
7
,
8
. Atoms are expected to recombine into molecules over the
nightside
9
, resulting
in different day-night chemistry. While metallic elements and a large
temperature contrast have been observed
10
–
14
, no
chemical gradient has been measured across the surface of such an exoplanet.
Different atmospheric chemistry between the day-to-night
(“evening”) and night-to-day (“morning”) terminators
could, however, be revealed as an asymmetric absorption signature during
transit
4
,
7
,
15
. Here, we report the detection of an asymmetric
atmospheric signature in the ultra-hot exoplanet WASP-76b. We spectrally and
temporally resolve this signature thanks to the combination of high-dispersion
spectroscopy with a large photon-collecting area. The absorption signal,
attributed to neutral iron, is blueshifted by −11±0.7 km
s
-1
on the trailing limb, which can be explained by a combination
of planetary rotation and wind blowing from the hot dayside
16
. In contrast, no signal arises
from the nightside close to the morning terminator, showing that atomic iron is
not absorbing starlight there. Iron must thus condense during its journey across
the nightside.
Liberalization and Discovery Böhme-Mehner, Tatjana
Contemporary music review,
02/2011, Letnik:
30, Številka:
1
Journal Article
Recenzirano
The last years of the existence of the GDR were characterized by a kind of liberalization, which also affected the arts, and allowed an opening of possibilities to establish a more official ...electroacoustic culture. This culture is presented in this article in the context of its social conditions-in particular, the role of the GDR group in the CIME, the Theater im Palast and the final opening of the electronic studio at Akademie der Künste are discussed.
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