Optimizing the abrasive sanding process of rubberwood (Hevea brasiliensis)

The abrasive sanding process is the most labor-intensive operation in the Rubberwood furniture manufacturing industry. Although the machining properties of Rubberwood (Hevea brasiliensis) are well established, information on its abrasive sanding characteristics is sparse. This study was carried out to establish the optimal abrasive sanding regime for Rubberwood. The results suggest that the abrasive sanding process can be optimized when well machine-planed Rubberwood stocks are used. Further, it was found that when the machine surface quality was good, abrasive sanding with a two-level sequence of grit sizes was sufficient to produce an acceptable surface smoothness. The improved surface smoothness also minimized the coating film spread on the wood surface. This finding will serve as a useful benchmark for machine-planing and abrasive sanding processes in the high-volume Rubberwood furniture manufacturing industry.     

Development and function of embryonic central nervous system glial cells in Drosophila

Each abdominal neuromere of a Drosophila embryo contains about 60 glial cells [Kl?mbt C, Goodman CS (1991): Glia 4:205-213; Ito et al. (1995): Roux's Arch Dev Biol, 204:284-307]. Among these, the midline and longitudinal glia are described to some detail. The midline glia are located dorsally in the nerve cord ensheathing the two segmental commissures. They are required for the proper establishment of commissures. The longitudinal glia, the A and B glia, and the segment boundary cells (SBC) are covering the longitudinal connectives. The longitudinal glia prefigure longitudinal axon paths and appear capable of regulating the expression of neuronal antigens. In the following we summarize the knowledge on the function of these glial cells.     

Charakterisierung von Glas und Glasbeschichtung mittels oberflächensensibler Sondenverfahren

The presented results of investigations by surface and microanalytical methods confirm the suitability of electron beam and scanning probe techniques for process monitoring, support of process development and defect analyses in the glass industry. More and more glass and coating specialists use the high tech service provided by an external laboratory with its wide range of experience and knowledge.     

Abschätzung der Ausbreitung brennender Ölnebel in Gasströmungen hoher Geschwindigkeit

Kräftegleichgewicht an fliegenden Tropfen. Beschreibung der Einflüsse auf die Flugbahnen von Partikeln konstanter Masse. Widerstandsbeiwerte und Massenabnahmegeschwindigkeit bei angeströmten Tropfenschwärmen. Zur Abschätzung der Flugbahnen von Tropfen veränderlicher Masse und von brennenden Ölnebeln sowie deren Ausbreitung in Kanalströmungen. Folgerungen für die Betriebsparameter von Druckzerstäuberbrennern.     

Statistischer Größeneinfluß unter mehrachsiger Wechselbelastung

Statistical Size Effect Under Alternating Load The results of 41 series of tests with smooth cylindrical and notched specimens, subjected to uni- and multiaxial alternating loads (tensioncompression, torsion, rotating bending and combined torsion and bending), are compared with theoretically predicted data. The prediction are based on the ?Weakest-Link-Concept”?. Multiaxial stresses are included either by means of suitable strength criteria, or by a fracturemechanical consideration of a crack in a multidimensional stress field. For the evaluation of the experimental data the 2-parametric Weibull's equation was used. The experimental and theoretical results may deviate by less than 20%, when the ratio between the strength at cyclic torsion and cyclic bending ist taken into account in the function of survival probability [eqns. (2), (7)].     

Comparison of chromosomal damage induced by X-rays and Ar ions with an LET of 1840 keV/micrometer in G1 V79 cells

Wound healing in the adult is commonly compromised by excessive scar formation. In contrast, fetal wound healing is a regenerative process characterised by the conspicuous absence of scarring. Available evidence suggests that phenotypic differences between fetal and adult fibroblasts are important determinants of these distinct modes of tissue repair. In this context, a number of groups (including our own) have documented differences between fetal and adult fibroblasts with respect to such potentially relevant characteristics as migratory activity, motogenic response to cytokines and the synthesis of motility factors, cytokines and matrix macromolecules. The oral mucosa appears to be a privileged site in the adult in that it continues to display a fetal-like mode of wound healing. Data are presented in this review indicating that a subpopulation of gingival fibroblasts expresses several 'fetal-like' phenotypic characteristics. These observations are discussed in terms of both the continued expression of a fetal-like mode of wound healing in the oral mucosa and the possible differential involvement of distinct fibroblast subpopulations in the progression of periodontal disease.     

A measuring method for quick determination of local heat transfer coefficients in spray water cooling within the range of stable film boiling

Within the framework of research investigations described in this paper, a measuring method for the determination of heat transfer coefficients in the range of stable film boiling has been developed for water spray cooling in the secondary cooling zone of continuous casting machines. Based on investigations by ³), a water cooled test sample with a measuring field of 20 × 20 mm² was constructed. For this sample geometry, a special evaluation method has been developed which permits quick evaluation in on-line procedure. Result of measurements are sections for the heat transfer coefficient arising from different spray water distributions. On the one hand, these can be used as calculation figures for the determination of the solidification profile and the solidification rate. On the other hand, the measuring results serve as an assessment basis for nozzle constructions. Practical use of the measuring results confirms the usefulness of the measuring method on a laboratory scale. In addition, the validity of the measuring results has been demonstrated by comparing them with an unsteady state method in accordance with ²).     

Information processing for the analysis of metabolic pathways and inborn errors

Methods of biotechnology allow the analysis of molecular structures and molecular processes. Different molecular database systems are available which allow worldwide data access. Methods and concepts of bioinformatics are important for the analysis of these molecular data, which represent complex regulatory networks. The detection of metabolic diseases is one application of information systems, which represents molecular and medical data and allows the stimulation of metabolic processes. In this paper we present the architecture of our molecular information system.