Process development for the assembly of microsystems with hot melt adhesives

In the assembly of microsystems, a reliable, precise, and fast joining process remains an open challenge. An approach using hot melt adhesives to join these micro parts is investigated within this article. A relevant issue with hot melt adhesives is introducing heat into the assembly process. This heat management can be achieved using either an active or passive concept. These concepts and their influence on process design are discussed. The realization of active heat management within a gripper is discussed in detail. Experimental results from an exemplary process show the applicability of the hybrid assembly process using hot melt adhesives.     

Cued repetition of self-directed behaviors in macaques (Macaca nemestrina).

Two macaques (Macaca nemestrina) were trained to perform 3 self-directed behaviors on signal and to repeat behaviors after a 'repeat' signal. The cognitive processes underlying the monkeys' repeat performance were evaluated via multiple repetitions of the repeat signal, extended delay periods between target behavior and repeat signal, and by transferring the repeat signal to novel behaviors. The monkeys seemed to use representations of their own past behaviors as a basis for repetition performance, but they mostly failed to correctly repeat target behaviors after extended delays and during transfer tasks. Implications for episodic memory abilities are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Texture as a reflection of microstructure

The perception of texture has been correlated to the microstructure of particulate whey protein gels. A full, two-level, factorial experimental design was used in which the processing conditions, pH, heating rate and addition of salt were used as design factors. The texture of the gels was analysed by a sensory panel, and the microstructure was analysed by light and electron microscopy. The microstructure was quantified by using different types of image analysis.

In this study of particulate whey protein gels, the test principles of analysing texture were divided into two groups: destructive tests and non-destructive tests. The microstructural parameters can also be divided into two groups: overall network dimensions (pore size and particle size) and strand characteristics. The texture as measured with destructive methods was sensitive to overall network dimensions, whereas texture as measured with non-destructive methods was sensitive to the strand characteristics of particulate protein gels.     

Efficient and inefficient aspects of residential energy behaviour: What are the policy instruments for change?

The empirical part of this study is based on a survey of 600 Swedish households and a number of interviews where questions about residential energy behaviour and possible policy instruments for change were raised. The study provides insight into current behavioural patterns and gives a bottom-up perspective on the realistic perspective potentials for change and ways to achieve them. Residential energy use accounts for a fifth of the total in Northern nations and patterns of behaviour may influence levels of energy use to the same extent as choice of appliances. The study revealed those behavioural patterns that are efficient and those that need to be improved for energy conservation. Several policy instruments for change were identified in the study and they include combinations of information, economic measures, administrative measures and more user friendly technology as well as equipment with sufficient esthetic quality. Policy instruments that have fostered energy efficient behaviour in Sweden include the massive information campaigns during the oil crises in the 1970s as well as energy labelling of appliances. Still, many households are “energy-unaware” and several energy efficient behaviours are motivated not by energy conservation concern but of a perceived lack of time. This shows that it is important to have a broad perspective in energy conservation, to evaluate trends and to use policy instruments timely to support or discourage them.     

Influence of cell shape and aggregate formation on the optical properties of flowing whole blood

We studied the influence of shape and secondary, or intercellular, organization on the absorption and scattering properties of red blood cells to determine whether these properties are of any practical significance for optical evaluation of whole blood and its constituents. A series of measurements of transmittance and reflectance of light from bovine blood in a flow cuvette was conducted with a 650-900-nm integrating sphere at shear rates of 0-1600 s(-1), from which the influence of cell orientation, elongation, and aggregate formation on the absorption (mu(a)) and the reduced scattering (mu(s)') coefficients could be quantified. Aggregation was accompanied by a decrease of 4% in mu(s)' compared with the value in randomly oriented single cells. Increasing the degree of cell alignment and elongation as a result of increasing shear rate reduced mu(s)' by 6% and mu(a) by 3%, evaluated at a shear rate of 1600 s(-1). Comparison with T-matrix computations for oblate- and prolate-shaped cells with corresponding elongation and orientation indicates that the optical properties of whole blood are determined by those of its individual cells, though influenced by a collective scattering factor that depends on the cell-to-cell organization. We demonstrate that cell morphological changes must be taken into consideration when one is conducting whole blood spectroscopy.     

The use of atomic force microscopy to measure the formation and development of chocolate bloom in pralines

Atomic force microscopy (AFM) has been used to study the surface of chocolate as well as the progress of chocolate bloom over time. Fresh chocolate was found to be relatively smooth but with deep holes. These could be pipes leading deep down into the body of the chocolate, perhaps reaching the filling. After storage for a few weeks, we observed the growth of small drops around these holes. With increasing time, these drops became larger and more structured. After further storage, a crystalline structure and bloom were revealed. These results suggest that bloom growth in pralines is a two-phase process, with drops initially forming on the surface and then bloom crystals nucleating and growing from them. Further, we deduced pipes leading down into the center of the chocolate through which the migration of filling fats can preferentially occur.     

Reflecting activities in product developing teams: conditions for improved project management processes

The study presented in this paper was designed to investigate the relationship between psychosocial aspects of project work and team-based activities that enable reflection upon project teams’ own practices. The study includes 144 project-active product developers in 20 Swedish manufacturing companies. Data were collected by means of a questionnaire survey. The main question addressed was how individual project members’ psychosocial work environment is related to participation and involvement in team-based reflecting activities. A further question was whether reflectivity in local project teams is related to improvement to overarching processes. The results show that three of the tested factors promote reflectivity in project teams, such as a high level of project work experience, a high level of time pressure, and extensive managerial support. It is also shown that reflecting activity at local project team level is associated with improvement to project management processes at a more general level.     

Raney Cobalt: An Effective and Recyclable Catalyst for the Pauson–Khand Reaction

Commercially available Raney cobalt is broadly applicable as a catalyst in intra‐ and intermolecular Pauson–Khand reactions (PKR). The activity of Raney cobalt compares favourably with that of previously described heterogeneous or heterogenised cobalt systems. The major reaction pathway appears to occur at the solid catalyst which can be efficiently separated and reused by filtration and/or exploiting its ferromagnetic properties.     

ALEMI: A Ten-Year History of Discussions of Alloying-Element Interactions with Migrating Interfaces

ALEMI is concerned with the interactions between Alloying Elements and Migrating Interfaces. A first meeting was held in conjunction with the 2000 TMS Fall Meeting in St. Louis, MO. About 22 attendees endorsed the principles contained in the invitation, which envisaged a more collaborative approach to the study of alloying element interactions with transformation interfaces, especially in alloy steels. The meetings were intended to be informal workshops emphasizing the sharing of ideas and plans for research. The development of a shared stock of alloys for research was planned, as well as the publication of summaries of discussions in an open, preferably archival, forum. Eight further meetings were held, often in conjunction with major conferences. An approximate equilibrium developed between discussions of theoretical matters and experimental results and methods. A remarkable number of those who attended the first meeting in St. Louis continued to participate. Research ideas were put forward, issues debated, collaborations fostered, and the science of transformation interfaces advanced.     

On the Symmetry Among the Diffusional Transformation Products of Austenite

Metallurgical and Materials Transactions A - Information on the diffusional transformation products of austenite in high-carbon steels is reviewed and supplemented with new microscopic studies. A...