Comparison of waste silica fillers modified with various proadhesive compounds

Results are presented on the improvement of the degree of surface hydrophobization of post-fluorine waste silicas. Two types of waste silica were used, representing by-products of aluminium fluoride and hydrofluoric acid production, respectively. The silicas were subjected to surface modification to obtain appropriately active fillers for the production of rubber vulcanizates and urethane elastomers. To this end, proadhesive compounds were used including surfactants, silane and titanate coupling agents, and organic compounds with oxyethylene chains. The effects of the type of proadhesive compound used and its amount on the mechanical properties of Ker 1500 butadiene-styrene rubber vulcanizates and of urethane elastomers were examined.     

Waste cement dusts as fillers for rubber compounds

The possibility of substitution of expensive active fillers, e.g. carbon black, for the waste products which can play the role of these fillers, e.g. the waste cement dusts or the waste post-HF silica, were investigated. The physico-chemical properties of the investigated waste cement dusts and the waste post-HF silica, as well as the strength properties of the rubber compounds containing these as fillers, were determined. To increase the activity and chemical affinity with the rubber, the waste cement dusts and the waste post-HF silica were modified by the use of adhesion promoters, that is alkoxysilanes. It was found that it would be possible to partly substitute carbon black for the waste cement dusts and the waste post-HF silica. The mixture ratio of a compound which had these wastes and showed the optimum strength properties was proposed.     

General modelling method of power losses in transmission with parameter identification

There is rarely a general or standard method to calculate the overall efficiency of a complete vehicle gearbox. This paper aims to develop such method which can possibly be applied to different types of transmissions in a flexible way and provide a platform to compare several different products from different OEMs or suppliers in parallel.A number of standards and publications concerning the calculation of power losses specifically for one transmission component such as gears, roller bearings or specific phenomenon like oil churning are available in the literature. Different models from these sources are compared, selected and combined to obtain the resulting efficiency map of a complete gearbox system.This paper presents the calculation of such a combined efficiency map of a transmission for an electric vehicle through either the standard models (ISO14179) for industry transmissions or this new joint overall model. The comparisons of available experimental data and calculations show that the result of the joint overall model has a better proximity to the test results. Nevertheless, the uncertainties in the input parameters of the model strongly affect the calculated power loss and the resulting efficiency of the gearbox. Parameter studies are conducted to determine the most influential parameters in the joint overall model. Several selected parameters are identified through experimental overall efficiency maps by classic parameter identification method and algorithm. On the one hand, a much better proximity is achieved. On the other hand, the identified parameters indicate the optimization potential of the component losses for benchmarking of transmissions.     

Partition-based workload scheduling in living data warehouse environments

The demand for so-called living or real-time data warehouses is increasing in many application areas such as manufacturing, event monitoring and telecommunications. In these fields, users normally expect short response times for their queries and high freshness for the requested data. However, meeting these fundamental requirements is challenging due to the high loads and the continuous flow of write-only updates and read-only queries that might be in conflict with each other. Therefore, we present the concept of workload balancing by election (WINE), which allows users to express their individual demands on the quality of service and the quality of data, respectively. WINE exploits these information to balance and prioritize both types of transactions—queries and updates—according to the varying user needs. A simulation study shows that our proposed algorithm outperforms competing baseline algorithms over the entire spectrum of workloads and user requirements.     

Fundamental experiments as benchmark problems for modeling ultrasonic micro-impact processes

Many ultrasonic processes are based on the mechanical contact of oscillating parts. Within ultrasonic machining (drilling, milling, grinding) micro impacts lead to abrasion at the processed workpiece and hopefully do not damage the tool. In ultrasonic motors ideally neither part gets worn. Thus the appropriate design of contact partners as well as their kinematics is a substantial task during the development of such devices. A first step to optimize contact mechanics is to understand their behavior and dependencies on parameter variations, such as vibration amplitude and pre-stress of the impacting parts. For a detailed understanding models validated with convincing experimental data from measurements are absolutely essential. This paper focuses on simple vibro-impact experiments which can be used as benchmark data for future models. The setup of the experiment and first experimental investigations are described in detail.     

Dental Inlay and Onlay Construction by Iterative Laplacian Surface Editing

We propose a new method for automatic construction of inlays and onlays. Mesh models from a small tooth library are adapted to the remaining healthy surface of the patient's tooth. In the area above the cavity, the general morphology of the model tooth (fissures, cusp tips, etc) is preserved, but precisely adjusted to the intra‐oral situation. Our approach uses iterative Laplacian Surface Editing to deform the model tooth. This allows the automatic generation of highly individual, functional and anatomically correct inlays/onlays, without having to resort to a large library of different tooth shapes.     

Malting revisited: Germination of barley (Hordeum vulgare L.) is inhibited by both oxygen deficiency and high carbon dioxide concentrations

During malting, barley (Hordeum vulgare L.) seeds are germinated to promote the mobilisation of storage compounds. Germination is strongly influenced by O₂ and CO₂; however, any distinction between the particular effects is missing. Since, in this study, the ambient O₂ concentration was maintained when high CO₂ concentrations were applied, for the first time the impacts of CO₂ and of O₂ deficiency could be distinguished unambiguously.Germination was inhibited by both O₂ deficiency and high CO₂ (80%) concentrations, documented by the lack of any growth of coleoptiles and any increase of α-amylase and β-glucanase activity. In contrast, the related impacts of O₂ starvation and high CO₂ on fermentation differ strongly, demonstrated by quite different patterns of ethanol emission. Additionally, the stress metabolism - monitored by the means of GABA accumulation - was also differently impacted. The elucidation of the underlying, so far unknown, mechanisms will provide novel opportunities to improve malting.     

Copper-Catalyzed Dehydration of Primary Amides to Nitriles

Abstract  

In the present study we introduce a copper-catalyzed protocol for the dehydration of primary amides to their corresponding nitriles applying N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) as silylation reagent. For that purpose investigations of various reaction parameters (copper source, solvent, temperature, MSTFA and copper loading) have been carried out to find suitable reaction conditions. Simple copper(I) chloride (2.5 mol%) and MSTFA (2.0 equiv) in toluene allow for the straightforward synthesis of a variety of nitriles (15 examples).     

Sulfate determines the glucosinolate concentration of horseradish in vitro plants (Armoracia rusticana Gaertn., Mey. & Scherb.)

BACKGROUND: Horseradish plants (Armoracia rusticana) contain high concentrations of glucosinolates. Former studies have revealed that Armoracia plants cultivated in vitro have markedly lower glucosinolate concentrations than those grown in soils. Yet, these studies neglected that the sulfate concentration in the growth medium may have had a strong impact on glucosinolate metabolism. Accordingly, in this study horseradish in vitro plants were cultivated with differing sulfate concentrations and the glucosinolate concentrations were quantified by ion pair HPLC. RESULTS: Cultivation in 1.7 mmol L^?1 sulfate (as used in the prior studies) resulted in the accumulation of 16.2 µmol g^?1 DW glucosinolates, while the glucosinolate concentration increased to more than 23 µmol g^?1 DW when 23.5 mmol L^?1 sulfate was used in the medium. Correspondingly, the glucosinolate concentration decreased to 1.6 µmol g^?1 DW when sulfate concentration was lowered to 0.2 mmol L^?1. CONCLUSION: Since the glucosinolate accumulation in relation to the sulfate concentration follows a typical saturation curve, we deduce that the availability of sulfate determines the glucosinolate concentration in horseradish in vitro plants. © 2012 Society of Chemical Industry     

Polyoxymethylene composites with natural and cellulose fibres: Toughness and heat deflection temperature

Cellulose and abaca fibre reinforced polyoxymethylene (POM) composites were fabricated using an extrusion coating (double screw) compounding followed by injection moulding. The long cellulose or abaca fibres were dried online with an infrared dryer and impregnated fibre in matrix material by using a special extrusion die. The fibre loading in composites was 30 wt.%. The tensile properties, flexural properties, Charpy impact strength, falling weight impact strength, heat deflection temperature and dynamic mechanical properties were investigated for those composites. The fibre pull-outs, fibre matrix adhesion and cracks in composites were investigated by using scanning electron microscopy. It was observed that the tensile strength of composites was found to reduce by 18% for abaca fibre and increase by 90% for cellulose fibre in comparison to control POM. The flexural strength of composites was found to increase by 39% for abaca fibre and by 144% for cellulose fibre. Due to addition of abaca or cellulose fibre both modulus properties were found to increase 2-fold. The notched Charpy impact strength of cellulose fibre composites was 6-fold higher than that of control POM. The maximum impact resistance force was shorted out for cellulose fibre composites. The heat deflection temperature of abaca and cellulose fibre composites was observed to be 50 °C and 63 °C higher than for control POM respectively.