The effective hydrodynamic radius of single DNA-grafted colloids as measured by fast Brownian motion analysis

Optical tweezers accomplished with fast position detection enable one to carry out Brownian motion analysis of single DNA-grafted (grafting density: ∼1000 molecules per particle, molecular weight: 4000 bp) colloids in media of varying NaCl concentration. By that the effective hydrodynamic radius of the colloid under study is determined and found to be strongly dependent on the conformation of the grafted DNA chains. Our results compare well both with recent measurements of the pair interaction potential between DNA-grafted colloids (Kegler et al. Phys Rev Lett 2008; 100:118302) and with microfluidic studies (Gutsche et al. Microfluid Nanofluid 2006; 2:381-386). The observed scaling of the brush height with the ion concentration is in full accord with the theoretical predictions by Pincus, Zhulina, Birshtein and Borisov.     

Cost-benefit analysis for disruption prevention in low-volume assembly

Manufacturing companies face rising pressure due to increased competition. Traditionally, companies have merely concentrated on offering impeccable, cost-efficient products. Today, however, flexibility and on-time delivery are additional requirements to satisfy the customers. At the same time, disruptions in production, especially in low-volume assembly, still frequently occur, leading to economic losses and delayed customer deliveries. The approach proposed in this paper strives for improving the disruption situation in low-volume assemblies. A detailed disruption management methodology has been developed, aiming at realizing an efficient reduction of disruptions, while at the same time considering the specific characteristics of low-volume assembly. The methodology is supported by a catalog of pre-emptive measures. These measures are known to reduce the disruptions’ occurrence or to diminish their consequences. In general, the approach pursues the basic idea to implement particularly those measures, which have the best cost-benefit-ratio. Based on the analysis of the cost-benefit-ratio of each measure, the developed methodology aims at improving the disruption situation in assembly and thus providing a high on-time delivery rate. The usability of the methodology for the low-volume assembly context has been confirmed by assembly experts on the basis of an application of the methodology in an exemplary case study.     

Tomographic multiaxis-differential optical absorption spectroscopy observations of Sun-illuminated targets: a technique providing well-defined absorption paths in the boundary layer

A novel experimental procedure to measure the near-surface distribution of atmospheric trace gases by using passive multiaxis differential absorption optical spectroscopy (MAX-DOAS) is proposed. The procedure consists of pointing the receiving telescope of the spectrometer to nonreflecting surfaces or to bright targets placed at known distances from the measuring device, which are illuminated by sunlight. We show that the partial trace gas absorptions between the top of the atmosphere and the target can be easily removed from the measured total absorption. Thus it is possible to derive the average concentration of trace gases such as NO(2), HCHO, SO(2), H(2)O, Glyoxal, BrO, and others along the line of sight between the instrument and the target similar to the well-known long-path DOAS observations (but with much less expense). If tomographic arrangements are used, even two- or three-dimensional trace gas distributions can be retrieved. The basic assumptions of the proposed method are confirmed by test measurements taken across the city of Heidelberg.     

Elektrische Messung hoher Holzfeuchten bei Fichte

A newly developed active electrode MH 34 for measuring high moisture contents in softwoods was used to determine the moisture distribution in cross-sections of specimens taken from freshly felled spruce and to measure the moisture contents of individual samples. A comparison was made between these results and measurements of moisture content after oven-drying. A relatively accurate representation was possible of the moisture distrubution, especially in the transition zone between sapwood and heartwood. For high moisure content ranges the electrically determined moisture content of individual specimens deviated from that of overn-dry samples by up to 30%. For larger samples average values of the entire moisture range showed a deviation from the actual moisture content of about 13%.     

Current research trends and prospects among the various materials and designs used in lithium-based batteries

Increasing energy consumption, shortages of fossil fuels, and concerns about the environmental impact of energy use, especially emissions of carbon dioxide, give fresh impetus to the development of renewable energy sources. With the advent of renewable energy, it is now indispensable that efficient energy storage systems have to be developed. One of the most promising storage systems to be employed in stationary energy storage applications are lithium-based batteries (LIB), mainly due to their high energy density, high power, and nearly 100 % efficiency. Within the scope of this paper, we carry out a patent search using the patent database PatBase^® to assess the development status of LIB technology. The analysis of the generated patent sample reveals disproportionately high growth rates in LIB patent applications over the last years compared to other selected energy-related technologies. Breaking down patent application growth by the different components of LIB shows the principal drivers of growth. The purpose of this paper is to provide current research trends and prospects for the main LIB materials and designs.     

Silane-Grafted Isotactic Polypropylene Used as a Coupling Agent on Glass. Consequences on The Interfacial Adhesion

Functionalized isotactic polypropylenes have been synthetized in order to be used as coupling agents on glass fibers associated with a polypropylene matrix. This new way of interface toughening requires a grafting of such polymeric chains on the glass surface and a crystallization of these grafted chains at the same time in the same crystals as the polypropylene matrix (co-crystallization). Using a Ziegler-Natta polymerization, copolymers based on propene and two different types of dienes have been prepared. Such a synthesis allows one to change the functionality and the position of double bonds used to introduce the silane functions. A Speier hydrosilylation was used for this purpose with two kinds of silanes. Silane-functionalized oligopropenes were also prepared in order to compare the effect of the position of the silane functions on the glass/polypropylene adhesion: side chain or chain end positions. The characterization of these functionalized polypropylenes is described. Their ability to be grafted on a glass surface was checked by means of wetting measurements after extractions according to the hydrophobic nature of the polypropylene and the hydrophilic character of the glass. The co-crystallization of the pure and functionalized polypropylenes was demonstrated on blends. Two silane functionalized-PP were selected to study the glass fiber/PP adhesion by means of the microdroplet test.     

Direct free-form deformation of NC programs for surface reconstruction and form-error compensation

In this paper a new approach for manufacturing modified workpieces by milling is presented. In course of product development, several optimization iterations are often required, in which the shape of the workpiece is modified. Conventional method for manufacturing modified workpieces includes a time-consuming and error-prone step of reverse engineering, where the new CAD/CAM data is generated with respect to the measurement data of the manufactured workpiece. The new approach generates a continuous deformation function in order to approximate the discrete displacement vectors between the initial and the modified shapes, and applies this function on the original NC programs of the workpiece. Hence, it is possible to directly manufacture the modified shape. The process of reverse engineering can be eliminated so that manufacturing costs and the time from workpiece design to the production decrease significantly.