EU‐Forschungsprojekt ESECMaSE – Teilprojekt Optimierung von Hochlochziegeln für Aussteifungswände

Unbewehrtes Ziegelmauerwerk hat sich in den letzten Jahrhunderten als geeigneter Baustoff in den mitteleuropäischen Erdbebenzonen bewährt. Erhöhte Anforderungen aus den Lastnormen waren der Anlaß für umfangreiche Untersuchungen zur Schubtragfähigkeit von Mauerwerk. Die Optimierung von Produkteigenschaften von Hochlochziegeln für schubbeanspruchtes Mauerwerk war dabei einer von mehreren Untersuchungsansätzen. Der Optimierungsprozeß wurde in dem von der Europäischen Kommission geförderten Forschungsprojekt ESECMaSE (Enhanced safety and efficient construction of masonry structures in Europe) durchgeführt. Dabei wurden sowohl Untersuchungen zur Optimierung der Materialzusammensetzung als auch eine Optimierung des Lochbildes vorgenommen. Als Optimierungsergebnis wurden Prototypen hergestellt und in statisch zyklischen Schubversuchen untersucht. Die wichtigsten Materialeigenschaften, insbesondere die Längsdruck‐ und Längszugfestigkeit wurden erheblich verbessert. Erste Ergebnisse von Schubversuchen zeigen jedoch, daß die Bedeutung der Längsdruckfestigkeit bei anisotropen Baustoffen wie Hochlochziegeln bisher deutlich überschätzt wird.     

Betriebsfestigkeit in der Fahrzeugentwicklung – von der Theorie zum Produkt

Durability Evaluation in the automotive engineering – from theory to product The procedures for durability evaluation in the automotive engineering are represented, especially the methods, load assumption, fatigue testing and the regulations for the release and quality control. By practical examples of the vehicle development from chassis, aggregate and body the procedure is described, in particular the used experimental and virtual simulation methods     

Elektronenstrahlschweißen an Atmosphäre – von der Entwicklung bis zum industriellen Einsatz

Non vacuum electron beam welding – from development to industrial application Attributable to the increasing degree of standardisation in many fields of industrial manufacturing, the saving of resources and thus the demand for light weight constructions and also the rapid development on the material sector have made joining tasks increasingly complex. This involves the joining method which must meet the metallurgical demands of the base materials to be welded and also the method’s profitability. In this connection, electron beam welding in atmosphere – NV‐EBW ‐ as a joining method is getting more and more important and is, from the side of the industry, becoming increasingly popular. NV‐EBW combines the many, well‐known advantages of electron beam welding in vacuum with the possibility to work under normal ambient pressure. With an equipment efficiency of more than 50 % and very high, achievable welding speeds of up to 60 m/min for aluminium materials, the electron beam in atmosphere is an efficient and profitable tool for welding. Under the direction of Professor U. Dilthey, the ISF has for many years and in close contact with industrial partners carried out research work in the field of the NV‐EBW technology. At that, elementary contribution to the development of rotationally‐symmetrical orifice assemblies and also to the testing and optimization of the method with regard to respective welding tasks has been carried out.     

ESCA – Untersuchungen zum Aufbau von Oxid-Schichten auf austenitischen Stählen nach Salpetersäurebeanspruchung.

ESCA – Investigations of the Passive Films Formed on Austenitic Stainless Steels in Nitric Acid By means of ESCA the composition and the thickness of passive films formed on austenitic stainless steels were investigated after the attack of nitric acid at various temperatures and acid concentrations. The outermost layers of the oxide film consist of SiO₂, then a layer rich of Cr-oxid follows, containing also some Mo in the four- and six-valent state. Ni does not contribute to the oxide film. Cr is also enriched in the metal just below the oxide film.     

Flussmittelfreies Hartlöten unter reaktiver Prozessgasatmosphäre – ein alternatives Verfahren zum Fügen von Aluminiumwerkstoffen

Flux‐free brazing under reactive process gas atmosphere – an alternative process for joining of aluminium materials Due to the high affinity of aluminium towards oxygen, joining of aluminium materials has ever been a challenge. In particular the efficiency of the process and the abandonment of fluxes during controlled atmosphere brazing have been within the focus of current research projects. The specific addition of reactive gases to the inert process gas atmosphere offers a suitable possibility of aluminium brazing without the use of fluxes. Under the application of hydrogen chloride the activation of the brazing and the workpiece surfaces is to be initiated, thus leading to dissolving the oxide layers. Moreover, the strongly reducing gas silane is used, which specifically removes oxygen and water residuals from the controlled atmosphere. Through a suitable controlled atmosphere brazing process the combination of both, reductive and activating additions, is to be used and tested upon their influence on the gas mixtures and materials used [1–5].     

Funktionalisierung der Oberfläche von Mikrostrukturen – Technologie und Anwendungen –. Functionalization of Microstructure Surfaces

Microtechnology enables the dimensioning and fabrication of cost‐effective novel platforms for bio diagnostics. By the employment of plasma technologies for specific adjustment of surface characteristics, custom‐designed platforms are feasible. For a fast and reliable adjustment of product properties, special test chips have been developed. The conclusions for this development and first products are presented in this article.     

Enhanced π–π Interactions of Nonfullerene Acceptors by Volatilizable Solid Additives in Efficient Polymer Solar Cells

Fine‐tuning of the nanoscale morphologies of the active layers in polymer solar cells (PSCs) through various techniques plays a vital role in improving the photovoltaic performance. However, for emerging nonfullerene (NF) PSCs, the morphology optimization of the active‐layer films empirically follows the methods originally developed in fullerene‐based blends and lacks systematic studies. In this work, two solid additives with different volatilities, SA‐4 and SA‐7, are applied to investigate their influence on the morphologies and photovoltaic performances of NF‐PSCs. Although both solid additives effectively promote the molecular packing of the NF acceptors, due to the higher volatility of SA‐4, the devices processed with SA‐4 exhibit a power conversion efficiency of 13.5%, higher than that of the control devices, and the devices processed with SA‐7 exhibit poor performances. Through a series of detailed morphological analyses, it is found that the volatilization of SA‐4 after thermal annealing is beneficial for the self‐assembly packing of acceptors, while the residuals due to the incomplete volatilization of SA‐7 have a negative effect on the film morphology. The results delineate the feasibility of applying volatilizable solid additives and provide deeper insights into the working mechanism, establishing guidelines for further material design of solid additives.     

Longitudinal compressive strength of masonry – Simplified calculation approach / Längsdruckfestigkeit von Mauerwerk – Vereinfachter Berechnungsansatz

For the structural analysis of the bending compression zone of masonry building elements, which are loaded under bending compression parallel to the bed joints, the longitudinal compressive strength of the masonry is required. According to the code, this value has until now been determined in laborious tests on masonry building elements or calculated analogously to the approach for the determination of the compressive strength perpendicular to the bed joints. In such a way, the actual failure mechanisms of masonry under compression loading parallel to the bed joints and relevant influential parameters for the longitudinal compressive strength however remain unconsidered. The article presents a proposal for the determination of minimum values of the longitudinal compressive strength of masonry in a simplified form for structural design purposes, which include consideration of both the relevant failure cases and also the significant influential parameters.     

Temperaturabhängigkeit des Verformungsverhaltens von Polytetrafluoräthylen-Schälfolie – Teil I: Versuche an ungekerbten Proben

Deformation behavior of polytetrafluoroethylene skived film as a function of temperature. Part I: Tests on unnotched samples . Polytetrafluoroethylene (PTFE) is suitable for use in anticorrosive linings of highly stressed chemical plant. The use of PTFE skived film which is cut to size and welded in place makes it possible to adapt lining techniques to the given geometric form of the steel parts to be lined. Considerable deformation of the PTFE skived film is necessary for such lining work, for example, at the intersection of a vessel body with a connecting pipe, at the crimp of a flange, etc. In order to avoid in such work nonuniformities and material damage such as cracks or overstraining, which leads to a tendency to crack when heated, and to avoid further processing difficulties as far as possible, the deformation behaviour under load of 4 mm thick PTFE skived film from four different manufacturers was studied in the tensile test at elevated temperatures between room temperature and 380°C. The film test not only yielded information about the material behaviour at temperatures of particularly good ductility, but also gave some idea of the similarities and differences between the properties of the PTFE skived films available on the market. Part I of this paper reports the test results obtained with unnotched test specimens and Part II will deal with the effects of notching. The conclusion derived from the present results is that pronounced deformations in PTFE skived film should be made at temperatures just under the crystalline melting point (327°C) and as near to it as possible since at this temperature the material is very ductile and shaping requires only small forces. Compared with deformation at room temperature, the shaping procedure becomes much less problematical even if PTFE skived film is heated to only 50…?100 °C.     

Untersuchungen zum Temperaturwechselverhalten von Gußeisen – Teil I: Einflußfaktoren auf das Temperaturwechselverhalten,experimentelle Untersuchungen und deren Ergebnisse

Test examining the temperature shift behaviour of cast iron – Part I: Influence on temperature shift behaviour experimental studies, and their results The first part of this article describes and discusses the most important influence on the temperature shift behaviour of cast iron materials. For some unalloyed and low – alloyed cast iron types the resistance to thermal shocks is measured using a test unit observing the temperature shift behaviour. Metallographic studies on tested materials round up the statements judging materials behaviour under thermal testing.     

Accidents in the U.S. and Europe: 1970–1980

This study compares certain demographic and accident characteristics among Western European countries and between Western Europe and the United States. The specific objectives of the study were to: (1) Identify various changes in fatalities and fatality rates experienced by each of eleven Western European Countries, by these countries as a whole, and by the United States from 1970 through 1980, with special attention given to the energy crisis and its aftermath from 1974 through 1980. (2) Determine whether there were statistically significant changes during the 1970–1980 time period in the traffic accident characteristics studied. The findings of this study are as follows: (1) During the decade studied. Western Europe as a whole experienced a fatality rate reduction per 10⁹ vehicle-kilometers traveled of 45.8% while the U.S. experienced a 29.1% reduction during this same period. (2) In Western Europe the age groups 0–14, 25–64 and over 64 and its road user groups pedestrians, bicyclists and motorcyclists and moped riders showed statistically significant improvements in the characteristics studied. The only U.S. group to experience a significant reduction in fatalities during this period was the age group 0–14; however the 1980 fatality rate per 10⁹ vehicle-kilometers of travel of 21.0 for the U.S., versus 34.8 for Western Europe, indicates that driving in the U.S. is still much safer.     

Plasmaborieren – Untersuchungen zum Einfluß der Glimmentladung beim Borieren in einer BCl3‐H2‐Ar‐Atmosphäre

Plasma Boriding – Influence of Glow Discharge Conditions Using a BCl₃‐H₂‐Ar‐Atmosphere The plasma boriding process using BCl₃‐H₂‐Ar‐atmosphere is analized by characterisation of glow discharge conditions using optical emission spectroscopy. Additional exhaust‐examination by mass spectrometry depending on treatment parameters contributes to the determination of the reaction mechanisms. Effects that have influence on plasma boriding using BCl₃ are investigated by comparison of the treatment results with the characterisation of the glow discharge. The etching mechanism on the substrate surface can be effectively reduced selecting optimised parameters. So the plasma boriding process using BCl₃‐precursor gets interesting for industrial application.     

Construction of Complex Co3O4@Co3V2O8 Hollow Structures from Metal–Organic Frameworks with Enhanced Lithium Storage Properties

A novel metal–organic‐framework‐engaged strategy is demonstrated for the preparation of multishelled Co₃O₄@Co₃V₂O₈ hybrid nanoboxes. This strategy relies on the unique reaction of zeolitic imidazolate framework‐67 with the vanadium source of vanadium oxytriisopropoxide. Benefitting from the synthetic versatility, a series of nanostructures can be realized including triple‐shelled and double‐shelled Co₃O₄@Co₃V₂O₈ nanoboxes and single‐shelled Co₃V₂O₈ nanoboxes. When evaluated as electrode materials for lithium‐ion batteries, these unique hollow structures demonstrate remarkable lithium storage properties. For example, the triple‐shelled Co₃O₄@Co₃V₂O₈ nanoboxes retain a high capacity of 948 mAh g^?1 after 100 cycles at 100 mA g^?1.     

Freestanding 1T‐MnxMo1–xS2–ySey and MoFe2S4–zSez Ultrathin Nanosheet‐Structured Electrodes for Highly Efficient Flexible Solid‐State Asymmetric Supercapacitors

Fabrication of hierarchical nanosheet arrays of 1T phase of transition‐metal dichalcogenides is indeed a critical task, but it holds immense potential for energy storage. A single‐step strategy is employed for the fabrication of stable 1T‐Mn_xMo_1–xS_2–ySe_y and MoFe₂S_4–zSe_z hierarchical nanosheet arrays on carbon cloth as positive and negative electrodes, respectively. The flexible asymmetric supercapacitor constructed with these two electrodes exhibits an excellent electrochemical performance (energy density of ≈69 Wh kg^?1 at a power density of 0.985 kW kg^?1) with ultralong cyclic stability of ≈83.5% capacity retention, after 10 000 consecutive cycles. Co‐doping of the metal and nonmetal boosts the charge storage ability of the transition‐metal chalcogenides following enrichment in the metallic 1T phase, improvement in the surface area, and expansion in the interlayer spacing in tandem, which is the key focus of the present study. This study explicitly demonstrates the exponential enhancement of specific capacity of MoS₂ following intercalation and doping of Mn and Se, and Fe₂S₃ following doping of Mo and Se could be an ideal direction for the fabrication of novel energy‐storage materials with high‐energy storage ability.