Improvement of accuracy in determining flow stress in hot upsetting tests

Knowledge of correct flow stress curves of steel at high temperatures is of essential importance for reliable plasto-mechanical simulations in materials processing and for an effective planning and designing of industrial hot forming schedules. Error considerations of flow curve determinations allow an estimation of the quality of flow curves. The experiments are performed on a computer controlled servo-hydraulic test maschine. Flow stress errors are calculated as a function of geometry deviations (due to thermal expansion, scaling, predeformation and inaccuracies in specimen geometry), temperature and strain rate deviations. The influence of friction and initial microstructure on flow curves have to be considered. Metal flow can be improved by using a suitable specimen geometry and lubricants. Thermal treatment before testing has to provide a microstructure, similar to the real structure of the material. Different initial microstructures (from varying thermal treatments) influence the overall magnitude of the flow stress curve. Using the flow stress data in a rolling simulation programme the effects on forming loads and torques are analysed.     

Influence of flow stress accuracy on the results of metal forming processes

During the determination of flow stress measuring errors in the range of ± 10% may easily occur. These measuring errors are transmitted to a greater or lesser extent to the FEM analysis. An evaluation of the influence of stress-strain curve errors in the FEM calculation of forming processes and its results was made using the ABAQUS programme package for the simulation of the rolling process and using the FINEL programme package for the simulation of the upsetting process. Both programmes describe force and equivalent stress with the same accuracy as the stress-strain curve does. Lateral and longitudinal flow behaviour appears relatively insensitive to measuring errors in the determination in the stress-strain curve, as does local strain. Attention should be payed, however, to the calculation of individual stress components. In these cases the errors may be compounded during the calculation.     

Polarization modulation-infrared reflection absorption spectroscopic mapping

Polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS) has been coupled with a stepwise mapping of the sample in order to characterize the molecular orientation across the surface. An optical setup has been developed to facilitate the PM-IRRAS mapping. With PM-IRRAS mapping used in conjunction with a common FT-IR spectrometer, the achievable lateral resolution of approximately 45 mum is energy-limited rather than diffraction-limited. PM-IRRAS mapping was used to study the molecular orientation of octadecanephosphonic acid (OPA) molecules attached on a microstructured aluminum oxide/gold surface. The spectroscopic map reveals that OPA is preferably spotty attached on the aluminum oxide surface. The attached molecules form a highly ordered film. A lower degree of ordering was found for phosphonic acid adsorbed on gold mainly in a tridentate bonding mode. Results demonstrate that PM-IRRAS mapping has a considerable potential for revealing inhomogenities within ultrathin films attached on a surface.     

Die Sanierung der stählernen Wagenhalle des Bornheimer Depots – Teil 1: Die konstruktive Ausbildung und Bewertung der Denkmalschutzwürdigkeit der beiden Stahlhallen und deren planerische Umgestaltung

The redevelopment of the iron tram shed from 1902 of the Bornheim tram depot in Frankfurt, Germany. There were two tram sheds dating from 1902 built in the rivet construction method on the grounds of the Bornheim tram depot in Frankfurt which as a whole is no longer required. The department for the protection of historical monuments classified the larger one of the two tram sheds, a building structure consisting of three naves, as a historical monument, thus corresponding to a report published by the ISIB (institute for welding technique & engineer's office Dr. Möll GmbH). The tram shed was bought by an investor who, in co‐operation with his architect, planned a modern shopping‐centre with the premise to conserve as much of the original building fabric as possible. The erection of an underground car park made the demolition of the tram shed inevitable. A concept of the ISIB was put into practice which recommended the deconstruction of the shed into transportable modules and to have them seen to by a company specialising in structural steelwork. Thereafter the concept recommended the application of a protective coating against steel corrosion and the installation of the necessary thermal insulation before rebuilding the tram shed at the same site but on top of the concrete roof slab of the underground car park.     

New concepts for lithium minerals processing

A new concept for the enrichment of lithium minerals is offering higher purity and higher yield by applying new processing technologies addressing the specific properties of the pegmatitic host rock. Additional value is created from high quality by-products which will improve the sustainability of mining activity and the overall cost base. Within the new concept, flotation may even be avoided where wet separation techniques are not applicable.Two innovative processing technologies have been integrated in the new concept: electrodynamic fragmentation and optical sorting. Detailed results of lab-technical tests show that the new process design can achieve highly selective liberation and separation processes. Optical and mineralogical analyses of the test products indicate a high benefit for commercial applications.     

Mortality, morbidity and costs attributable to smoking in Germany: update and a 10-year comparison

Objective

To assess the negative health consequences and associated costs of cigarette smoking in Germany in 2003 and to compare them with the respective results from 1993.

Methods

The number of deaths, years of potential life lost (YPLL), direct medical and indirect costs caused by active cigarette smoking in Germany in 2003 is estimated from a societal perspective. The method is similar to that applied by Welte et al, who estimated the cost of smoking in Germany in 1993. Therefore, a direct comparison of the results was possible. Methodological and data differences between these two publications and their effect on the results are analysed.

Results

In 2003, 114 647 deaths and 1.6 million YPLL were attributable to smoking. Total costs were €21.0 billion, with €7.5 billion for acute hospital care, inpatient rehabilitation care, ambulatory care and prescribed drugs; €4.7 billion for the indirect costs of mortality; and €8.8 billion for costs due to work loss days and early retirement. From 1993 to 2003, the proportionate mortality attributable to smoking remained relatively stable, rising from 13.0% to 13.4%. The smoking‐attributable deaths in men is lowered by 13.7% whereas that in women increased by 45.3%. Total real direct costs rose by 35.8%, and total real indirect costs declined by 7.1%, rendering an increase of 4.7% to real total costs. Accountable factors are changes in cigarette smoking prevalence and in disease‐specific mortality and morbidity, as well as a rise in general healthcare expenditure.

Conclusions

Despite the growing knowledge about the hazards of smoking, the smoking‐attributable costs increased in Germany. Further, female mortality attributable to smoking is much higher than it was in 1993.As a result of the devastating health consequences of smoking, many countries have implemented anti‐smoking measures. For example, Ireland and Italy banned smoking in all public buildings and at all workplaces, including pubs and restaurants. Several publications have shown that Germany is still rather friendly to the tobacco industry.¹ This is also supported by recent decisions not to implement a smoking ban or to prohibit smoking in all public places. However, Germany increased the tax on tobacco products three times since 2004, which decreased cigarette sales and smoking prevalence in the age group 12–17 years.^2,3The first cost‐of‐smoking study for Germany used 1993 as the reference year,⁴ and was published by some of us. Since then, three other studies have been published: one is by Ruff et al,⁵ which cannot be used for comparison because of a lack of methodological transparency, and two by Wegner et al,^6,7 which considered only indirect costs. Thus, costs of smoking can be compared with only the first study.This study presents the most recent estimate for both direct and indirect costs of cigarette smoking in Germany, based on the latest available data and referring to the year 2003. As a similar method was applied, costs of smoking can be directly compared between 1993 and 2003.     

Wachstum der Weltbevölkerung und nachhaltige Tragfähigkeit

Das globale Wachstum der Weltbev?lkerung und die Folgen der zunehmenden Verst?dterung lassen angesichts der weltweiten Verbreitung von Armut und Unterern?hrung die Frage nach den künftigen Grenzen der agraren Tragf?higkeit der Erde aufkommen. Das von den UN-Modellrechnungen, die in der vorliegenden Ver?ffentlichung im überblick vorgestellt werden, vorausberechnete weitere Bev?lkerungswachstum und der Fl?chenverbrauch durch die zunehmende Verst?dterung und Industrialisierung lassen die pro Kopf der Weltbev?lkerung für die Nahrungsmittelproduktion verfügbare Anbaufl?che bis zur Jahrhundertmitte deutlich schrumpfen. Hinzu kommen die gegenw?rtig nur schwer absehbaren Auswirkungen von Bodendegradation und Klimawandel auf die Produktion von Nahrungsmitteln. Ob es hinsichtlich der Tragf?higkeit eine mehr als theoretische Grenze für die Zahl an Menschen gibt, die auf der Erde unter optimalen Bedingungen ern?hrt werden k?nnen, ist umstritten. Trotz eines Rückgangs an agrarer Nutzfl?che pro Kopf geht die FAO in ihrer Prognose aktuell davon aus, dass das globale Angebot an Kalorien pro Kopf der Weltbev?lkerung bis 2030 gesteigert und die Anzahl von Unterern?hrung betroffener Menschen deutlich reduziert werden kann. Unter dem Aspekt der Nachhaltigkeit ist die Produktion von Nahrungsmitteln aber vor allem im Kontext der aktuellen Produktionsbedingungen und der Konkurrenz zu anderen Konsumbereichen zu betrachten und diesbezüglich ist nach Berechnungen des Global Footprint Networks, die hier herangezogen werden, bereits in den 1980er Jahren die Biokapazit?t der Erde für eine nachhaltige Entwicklung überschritten worden. Setzt sich die derzeitige Entwicklung fort, wird unter Einbeziehung des von der UN angenommenen globalen Bev?lkerungswachstums die Biokapazit?t der Erde bis 2050 um mehr als das Doppelte überschritten werden. Eingegangen: 9. Januar 2009; angenommen: 16. Januar 2009 http://www.bib-demographie.de     

Sea transport of bananas in containers – Parameter identification for a temperature model

Losses of product quality during the sea transport of bananas in containers are related to the emergence of hot spots. In order to analyze critical conditions, a spatial temperature profile was recorded ashore in a container loaded with banana pallets. The identification of a structured system model showed that it is possible to reduce the information on the measured temperature curves to a set of only two index values. These can be interpreted as factors for coupling to the air stream and for the amount of heat generated by biological processes per banana box. The width of gaps between pallets was identified as the major influence on the spatial temperature profile. Boxes from which the unwanted banana ripening heat cannot be channeled away by the cooling unit can be detected by the quotient of the index values.     

Identification and evaluation of volatile odor-active pollutants from different odor emission sources in the food industry

In order to elucidate the nature of different odor-emission sources in the food industry, odor-active pollutants of the exhaust air in the cooling gases from coffee bean roasting, the exhaust air of fish meal production, and the exhaust air of swine breeding were investigated. Knowledge of what pollutants are present in the odor emission and are responsible for the malodor is vital to the development of suitable adsorbers/absorbers and filters, and combinations of the same. Therefore, the objective of these investigations was to identify and evaluate the characteristic impact of compounds in the exhaust air of these odor-emission sources. The volatile compounds were collected by using a microprocessor-controlled gas sampler through sorbent tubes of Tenax TA. The adsorbed compounds were analyzed by thermal desorption into a cryotrap and subsequent gas chromatography separation, followed by simultaneous olfactometry and mass spectrometry. In cooling gases of the coffee bean roasting numerous compounds (up to 100) were identified of which only 22 were important for the characteristic odor. These compounds were aldehydes (2-methyl propanal, 2- and 3-methyl butanal, 2-furancarboxyaldehyde, 5-methyl-2-furancarboxyaldehyde), diketones (2,3-butandione, 2,3-pentandione), pyrazines, pyridine, acetic acid, and furanmethanol. Other compounds with low concentrations but with a very low odor threshold and, therefore, important for the total odor were 3-methyl butanoic acid and guaiacol. Up to 50 compounds were identified in the exhaust air of fish meal production, the most significant of these being trimethylamine. Trimethylamine, with a very low odor threshold (0.0025 g/l air) and the highest content (up to 60% in the total ion chromatogram, more than 100 g/l) in the exhaust air of fish meal production, was responsible for the characteristic fishy odor. Beside trimethylamine only a few compounds, e.g., sulfides (dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide), aldehydes (2-methyl propanal, 2- and 3-methyl butanal), ethanol, and guaiacol, played a secondary role for the total odor. In the exhaust air of the pig house up to 50 compounds were identified. Beside ammonia, the most important odor-active compounds were various carboxylic acids (acetic acid, butanoic acid, 3-methyl butanoic acid), sulfides (dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide), trimethylamine, and the intensive odor-active p-cresol and 4-ethylphenol.