Investigation of the coating thickness of plasma-transferred arc deposition welded and cross wedge rolled hybrid parts

Most of today’s technical parts and components are made of monolithic materials. These mono-material components produced in established production processes reach their limits due to their respective material characteristics. Thus, a significant increase in production quality and efficiency can only be achieved by combining different materials in one part. Bulk forming of previously joined semi-finished products to net shape hybrid components that consist of two different materials is a promising method to produce parts with locally optimized characteristics. This new production process chain offers a number of advantages compared to conventional manufacturing technologies. Examples are the production of specific load-adapted forged parts with a high level of material utilization, an improvement of the joining zone caused by the following forming process and an easy to implement joining process due to the simple geometries of the semi-finished products. This paper describes the production process of hybrid steel parts, produced by combining a plasma-transferred arc deposition welding process with a subsequent cross wedge rolling process. This innovative process chain enables the production of hybrid parts. To evaluate the developed process chain, coating thickness of the billet is analysed before and after cross wedge rolling. It could be shown, that the forming process leads to an improvement of the coating, meaning a more homogeneous distribution along the main axis.     

Channel changes associated with two adjacent weirs on a regulated lowland alluvial river

Survey data from 1906 and 1988 for the lower River Murray, Australia, reveal changes in channel morphology associated with the construction of Locks 2 and 3 (1925–8), which form contiguous pools in the Valley and Gorge sections, respectively. Regulated annual flows are less than half the volume of natural flows, and the frequency of maximum flows has decreased. Upstream weirs have reduced the sediment supply to the study reach by 1.05 × 10⁶ tonnes per annum. The trap efficiencies of Pools 2 and 3 from 1906 to 1988 were 8 and 13% respectively, with retention channel of 80723 and 267470 tonnes. Responses over the past 60–70 years have differed between the pools-some channel characteristics have attained a new dynamic equilibrium and others have not. In Pool 3 the average bed slope has been reduced by 000004 (44%) and has attained equilibrium, but in Pool 2 the supply and redistribution of sediment have not been sufficient to reduce the bed slope. There are continuous areas of degradation and aggradation in Pool 3 but discontinuous areas in Pool 2, reflecting different stages in slope adjustment. Cross-sections have become wider and shallower in Pool 3 but narrower and deeper in Pool 2. These adjustments are influenced by local boundary conditions, floodplain morphology and the position of the study reach in the sequence of weirs. In general, the situation in the lower Murray does not conform to conventional models of the impact of regulation, which are based on data from upland dams. The Murray's gross morphology remains as a relict of the natural, semi-arid regime. Low contemporary stream energies and cohesive bank materials restrict the initiation of channel metamorphosis and prolong the time required for the completion of channel adjustment.     

Einflüsse von Mo,V, Nb,Ti, Zr und deren Karbiden auf die Korrosion und Wasserstoffaufnahme des Eisens in Schwefelsäure

Effects of Mo, V, Nb, Ti, Zr and their carbides on the corrosion and hydrogen uptake of iron in sulphuric acid The effects of Mo, V, Nb, Ti, Zr and their carbides on the corrosion and hydrogen uptake of iron in 1 M H₂SO₄/N₂/25°C were investigated by electrochemical and surface analytical methods using binary and ternary Fe-Me alloys with about 0.2 at.-%Me. Due to the experimental conditions, no protective surface layers formed. The transition metals were enriched at the iron surface only as a carbide or oxicarbide. Mo or Zr were not markedly enriched. The corrosion current density and the hydrogen activity were decreased only by Mo or Zr. Hydrogen permeation measurements were analysed in terms of the trapping theory. The average binding energy of shallow traps for hydrogen increases with increasing atomic radius of the substituted alloying elements in the order V, Mo, Ti, Nb and Zr. Correspondingly, the hydrogen diffusion coefficient (after saturation of the deep traps) decreases and the hydrogen solubility increases. The steadystate hydrogen permeation rate remains almost unaffected. The total hydrogen content is determined by the density of deep traps and thus mostly independent of the external hydrogen activity. The trapping effect of iron is strongly increased by dissolved Zr or Nb or in the presence of fine dispersed carbides as VC_x. The effect of coarse carbide particles at a lower density is small.     

Strategies for carbon dioxide emissions reductions: Residential natural gas efficiency,economic, and ancillary health impacts in Maryland

As part of its commitments to the Regional Greenhouse Gas Initiative (RGGI), the State of Maryland, USA, auctions emission permits to electric utilities, creating revenue that can be used to benefit consumers and the environment. This paper explores the CO₂ emissions reductions that may be possible by allocating some of that revenue to foster efficiency improvements in the residential sector’s use of natural gas. Since these improvements will require changes to the capital stock of houses and end use equipment, efficiency improvements may be accompanied by economic and ancillary health impacts, both of which are quantified in this paper.     

Between Promise and Threat

ZUSAMMENFASSUNG: Produktion und Verbrauch von Nahrungsmitteln sind traditionell mit weit reichenden ?ngsten verknüpft. Bezogen diese sich in vormodernen Gesellschaften vorrangig auf eine ausreichende Versorgung, sind sie in der modernen Industriegesellschaft eher auf die Qualit?t der Nahrungsmittel gerichtet. In diesem Zusammenhang spielten in der Nachkriegszeit Antibiotika eine zentrale Rolle. Der Aufsatz stellt die Einführung der Antibiotika in die westdeutsche Veterin?rmedizin, ihre frühe Diskussion als Konservierungsmittel und ihre wachsende Rolle als Wachstumsf?rderer dar. Vor dem Hintergrund einer zunehmend industrialisierten, auf Maximierung ausgerichteten Produktionspolitik werden die Rolle der Veterin?re, der Forschung und der wissenschaftlichen Experten sowie die Probleme der Regulierung des Antibiotikaeinsatzes in der Landwirtschaft diskutiert, die in die Entstehung eines unübersichtlichen grauen Marktes für Antibiotika und die Verlagerung ihres Einsatzes in die Therapie mündete. Besondere Aufmerksamkeit wird der Frage zugewandt, welche Rolle das Vertrauen und die ?ngste der Verbraucher in diesem Prozess spielten.     

Compression of the urethra by an arthrotic cyst

A case is presented of an osteoarthrotic cyst of the pubic symphysis with a diameter of 32 mm that caused urinating problems because of posterior dislocation and compression of the urethra. X-rays showed osteoarthrosis of the pubic symphysis, and the 56-year old woman had a history of separation of the pubic symphysis at the age of 28.