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11. Thermoplastic foam injection moulding of sandwich structures with short fibre-reinforced skin layers.

Author

Loypetch, N, Tröltzsch, J, Nestler, D, Kroll, L, and Siengchin, S

Subjects
SANDWICH construction (Materials), BLOWING agents, INJECTION molding, THERMOPLASTIC composites, CORE materials, FOAM
Abstract

Sandwich structures, consisting of a short glass fibre–reinforced polypropylene film as skin layer and chemically blown polypropylene as the core material, were produced via injection moulding. The skin layers of the sandwich structures, which contain polypropylene as well as 30 wt% and 50 wt% of glass fibres namely polypropylene–glass fibres 30 and polypropylene–glass fibres 50 respectively, were produced by film extrusion using a coat hanger die. The properties of the films were investigated by dynamic mechanical analysis. Furthermore, the influence of different glass fibre contents in the skin layers and chemical blowing agent contents in the core material of sandwich structures was studied to compare them with the compact polypropylene and the polypropylene foams. The sandwich structures were characterized with regard to density, microstructure, weight reduction, surface roughness and bending properties. In general, distinctive reinforcement effect was achieved by use of the short glass fibre with the strong influence of processing direction of the film. For the sandwich structures, it was found that a good adhesion between the skin layers and the core material can be achieved during injection moulding. The microstructure and the bending properties of the sandwich structures depend on the glass fibre–reinforced film and the chemically blown core. It was found that the use of the skin layers led to lower cell intensity in the foam core. Nevertheless, a high modulus and strength to weight ratio could be accomplished by a high stiffness of the glass fibre–reinforced film and a low density of the chemically blown core. Additionally, it was found that the surface roughness of the films could be reduced due to processing in injection moulding. [ABSTRACT FROM AUTHOR]

Published
2021
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18. Methodical aspects of magnetic nanoparticle induced thermotherapy of glioblastoma recurrences on the basis of phase II data

Author

Niehoff, H., Wust, P., Nestler, D., Ulrich, F., Budach, V., and Maier-Hauff, K.M.

Subjects
ddc: 610, 610 Medical sciences, Medicine, neoplasms
Abstract

Objective: Efficacy enhancement of re-irradiation of glioblastoma recurrences by nanoparticle induced local thermotherapy seems to be a promising treatment option for patients with recurrent malignant glioma. The sensitizing effect of heat in treating cancer with chemo- and radiotherapy has been known[for full text, please go to the a.m. URL], 62. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgen (PNCH)

Published
2011

31. Continuous splitting of carbon fibre rovings.

Author

Mäder, Th, Trautmann, M., Nestler, D., and Wielage, B.

Subjects
CARBON fibers, ELECTRODES, ELECTROCHEMICAL cutting, ELECTRIC resistance, STRAINS & stresses (Mechanics)
Abstract

Carbon fibres are fabricated in bundles. A single roving contains a minimum of 1000 filaments. Certain applications demand thinner bundles or even single fibres. Single fibres can be used as tool electrodes in electrochemical machining processes. Thinner rovings are needed in sensor applications to raise the electrical resistance of the carbon fibre bundle used as strain sensor. Rovings with a lower filament count cannot be delivered by carbon fibre producers. A splitting technology is therefore needed. A continuous bundle splitting technique was developed. It uses mechanical means, liquid flow and variations in winding force and speed to separate the filaments. The impact of winding parameters and of the liquid flow on the splitting result was quantified in experiments with the developed splitting system. An automatic and continuous splitting of carbon fibre rovings was realised. Smaller bundles of carbon fibre filaments can be provided. There is a solution to satisfy the demand on finer carbon fibre rovings. [ABSTRACT FROM AUTHOR]

Published
2016
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41. Ablative performance of carbon-carbon nosetips in simulated re-entry environments

Author

Nestler, D. E

Subjects
Composite Materials
Abstract

A summary is presented of ablation performance data for carbon-carbon nosetip models obtained over a range of pressures from 10 to 168 atm. Two classes of tests are reviewed: (1) steady state, in which a constant environment is imposed on the model, and (2) ramp, in which the pressure is increased from 10 to 80 atmospheres to simulate re-entry pressure history. Comparison of arc test parameters with typical reentry vehicle parameters is included, to assess the adequacy of the test simulation. Based on this comparison, recommendations are made for facility developments which would yield improved simulation capability for reentry vehicle nosetip ablative performance.

Published
1977

46. Use of an electronic patient tracking system to facilitate clinical research in the emergency department

Author

Smith, V., Boggust, A., Russi, C., Nestler, D., and Hess, E.P.

Subjects
Emergency medicine -- Usage, Medical research -- Usage, Medicine, Experimental -- Usage, Clinical trials -- Usage, Hospitals -- Emergency service, Hospitals -- Usage, Health, Health care industry, Science and technology
Abstract

Introduction: Electronic patient tracking systems are commonly used in emergency departments (EDs) to facilitate patient care and monitor ED flow. We report the successful modification of an existing electronic patient tracking system to facilitate planning and conduct of a prospective cohort study. Methods: We extracted data from an existing ED registration database for patients with 'chest pain,' 'chest,' 'pressure,' 'tightness,' 'radiating,' or 'angina' registered as a chief complaint or final diagnosis. These synonyms were then used to generate a list of potentially eligible study participants over a 1-year period. We then implemented an automated notification system triggered by chief complaint data entered into the patient tracking database at the time of ED registration that simultaneously activated an electronic paging system and generated an email. Study coordinators then scanned the email list on a daily basis to determine the number of eligible participants and cross-referenced the list with completed case record forms to determine the number of potentially eligible, eligible enrolled and missed eligible patients. Analyses included descriptive statistics. Results: From July 1, 2007 to July 1, 2008 there were 3233 patients with a chest pain related synonym registered as a chief complaint. From November 1, 2008 to December 1, 2008 there were 257 automatically generated electronic notifications. Of these 257 notifications, 150 (58.4%) patients met eligibility criteria. One-hundred twenty-five (83.3%) eligible patients were enrolled, and 22 (14.7%) eligible patients were missed. Conclusion: We report the successful modification of an existing electronic patient tracking system to facilitate ED-based clinical research. Our system can be used to assess feasibility for prospective studies, generate real-time electronic notification of potentially eligible participants, and monitor enrollment. Keywords: electronic patient tracking, clinical research, study logistics

Published
2009

50. Untersuchungen zur Herstellung siliziumkarbidpartikelverstärkter Aluminiumpulver durch Hochenergiekugelmahlen

Author

Wielage, B., Nestler, D., Siebeck, S., and Podlesak, H.

Abstract

Die Herstellung von SiliziumkarbidAluminiumVerbundpulver stellt die erste Stufe der pulvermetallurgischen Herstellungsroute für partikelverstärkte Aluminiumwerkstoffe dar. Der Prozess der Verbundpulverausbildung beim Mahlen in einer Hochenergiekugelmühle und der Einfluss von Prozessparametern werden anhand der AlLegierung EN AW2017 mit 10 und 15 Vol. Siliziumkarbidteilchen der Kornfraktion <2 μm untersucht. Die Gefügeentwicklung des Pulvers wird materialografisch charakterisiert. Bestimmte Prozessparameter beeinflussen den Verbundpulverzustand zum Teil gegenläufig, so dass der erreichte Optimierungsstand als Kompromiss anzusehen ist. Lösungsvarianten für eine weitere Verbesserung werden aufgezeigt.The fabrication of aluminium siliconcarbide composite powder is the first step of the powder metallurgical production of particlereinforced aluminium material. This paper deals with the production of siliconcarbide reinforced aluminium matrix AA2017 composite powder through an high energy ball milling process by using simoloyer and planetary high energy mills. The Stages of composite powder formation during the highenergy ball milling process will be shown by means of materialographic studies and by micro hardness. Major factors of influence as well as typical problems are discussed.

Published
2010
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