Application of Wood Composites

This Special Issue "Application of Wood Composites" addresses various aspects of these important wood materials’ use. Topics include the mechanical processing of wood composites, including their cutting, milling, or sanding, incorporating current analysis of wood dust or grain size measurements and the composition of particles; scientific views on the influence of various adhesives in the creation process of wood composites and the analysis of their behavior in contact with various wood elements under different conditions; the analysis of input raw materials forming wood composites, including various wood species, but also non-wood lignocellulosic raw materials; and, last but not least, the analysis of bark, which in recent years has become an important and promising raw material involved in the construction of wood composites. The study of the development of the sliding table saw also suitably complements this Special Issue

NASA Tech Briefs Index, 1976

Abstracts of new technology derived from the research and development activities of the National Aeronautics and Space Administration are presented. Emphasis is placed on information considered likely to be transferrable across industrial, regional, or disciplinary lines. Subject matter covered includes: electronic components and circuits; electronic systems; physical sciences; materials; life sciences; mechanics; machinery; fabrication technology; and mathematics and information sciences

A systematic approach for integrated product, materials, and design-process design

Designers are challenged to manage customer, technology, and socio-economic uncertainty causing dynamic, unquenchable demands on limited resources. In this context, increased concept flexibility, referring to a designer s ability to generate concepts, is crucial. Concept flexibility can be significantly increased through the integrated design of product and material concepts. Hence, the challenge is to leverage knowledge of material structure-property relations that significantly affect system concepts for function-based, systematic design of product and materials concepts in an integrated fashion. However, having selected an integrated product and material system concept, managing complexity in embodiment design-processes is important. Facing a complex network of decisions and evolving analysis models a designer needs the flexibility to systematically generate and evaluate embodiment design-process alternatives. In order to address these challenges and respond to the primary research question of how to increase a designer s concept and design-process flexibility to enhance product creation in the conceptual and early embodiment design phases, the primary hypothesis in this dissertation is embodied as a systematic approach for integrated product, materials and design-process design. The systematic approach consists of two components i) a function-based, systematic approach to the integrated design of product and material concepts from a systems perspective, and ii) a systematic strategy to design-process generation and selection based on a decision-centric perspective and a value-of-information-based Process Performance Indicator. The systematic approach is validated using the validation-square approach that consists of theoretical and empirical validation. Empirical validation of the framework is carried out using various examples including: i) design of a reactive material containment system, and ii) design of an optoelectronic communication system.Ph.D.Committee Chair: Allen, Janet K.; Committee Member: Aidun, Cyrus K.; Committee Member: Klein, Benjamin; Committee Member: McDowell, David L.; Committee Member: Mistree, Farrokh; Committee Member: Yoder, Douglas P

DEVELOPMENT OF HUMAN TISSUES ON A CHIP FROM PLURIPOTENT STEM CELLS

The development of new microscale technologies aimed at generating human tissues and organs on a chip is emerging as a novel effective strategy to perform cost effective and multi-parametric assays for disease modeling investigations and screening specific therapeutic strategies, as broadly recognized from the scientific community, the major pharmaceutical companies and the governmental agencies. The generation of human organs on a chip, in which microscale technologies, such as microfluidics, are combined with cultured human cells in order to mimic whole living organ environment, offers a unique opportunity to study human physiology and pathophysiology, resembling in vivo conditions. This technological perspective could provide an effective solution to the current limitations of animal models, which result highly expensive and non predictive of human physiology, and conventional cell culture models that fail to recapitulate complex, organ-level disease processes. The possibility of developing direct organogenesis on a chip from human pluripotent stem cells, which have the potential to generate all cellular types of the human body, could overcome the limited availability of human primary cells, such as human hepatocytes or cardiomyocytes. Moreover, the recent generation of human induced pluripotent stem cells (hiPSCs) from adult somatic cells through the ectopic expression of defined transcription factors, provides a new effective tool to obtain populations of patient-specific stem cells with distinctive genetic diversity. This work is aimed at the development of functional human tissues on a chip from pluripotent stem cells, to be used in developing new in vitro disease models or drug screening and toxicity assays, more predictive than current animal models, overcoming issues related to primary cell sources recruitment. To this purpose, an integrated microscale system, based on the microfluidic technology, was developed, in order to derive functional cardiac and hepatic tissues on a chip, from human pluripotent stem cells, through the accurate delivery of chemical compounds and growth factors, within cellular microenvironment, and proper regulation of exogenous and endogenous factors, which are known to affect embryonic development in vivo. These functionally differentiated cells on a chip can be directly used for multi-parametric and large-scale drug screening or for developing micro-engineered human organ models. This last aspect also requires to design new technology for assisting in vitro assays and developing new therapeutic strategies or for screening among potential clinical cures. In particular, design of proper functional assays to test cellular responses to drugs or external stimuli, such as mechanical stress or hypoxia, in a physiologic or pathologic context has been addressed. Thanks to the development of a microfluidic gas exchanger for generating rapid depletion of oxygen content in culture medium, the role of acute hypoxia in calcium handling machinery of a cardiomyocytes population was investigated, mimicking early effects of ischemia on cardiac microenvironment. Moreover, the role of cyclic mechanical stress, which plays a crucial role in the investigation of new physiological and pathological responses to cell culture microenvironment, was analyzed in a human Duchenne Muscular Dystrophy (DMD) in vitro model, through a microfluidic-based cell stretching device accurately reproducing cyclic mechanical deformations along time. The combination of tissues development on a chip and micro-technology assisting for functional assay on a chip opens new and substantial perespective in generating a human in vitro model that properly resemble the physiological and pathophysiological behaviro of a tissues or organs within humna body

Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14

Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences