Holographic Recording Materials Development

Organic photorefractive materials were evaluated for application in a reversible holographic memory system. Representative indigo and thioindigo derivatives and several stilbene derivatives were studied as well as 15, 16-dialkyldihydropyrene derivatives the following goals were achieved: (1) the successful writing of phase holograms in a thioindigo/polymer gel system, (2) the successful writing and erasing of phase holograms in a variety of indigo/polymer gel and indigo/solid polymer systems, and (3) the identification of indigoid dyes and 15, 16-dialkyldihydropyrene derivatives as materials potentially suitable for utilization in an operational system. Photochemical studies of the stilbene, indigo, thioindigo, and dialkyldihydropyrene derivatives in solution and in a variety of polymer matrix materials were conducted with the goal of optimizing the photorefractive behavior of the chemical system as a whole. The spectroscopic properties required of optimal photorefractive materials were identified, and it was shown that both the indigoid dyes and the dialkyldihydropyrenes closely match the required properties

PROCESS MODELING FOR FLUID-INTERFACE SUPPORTED RESIN PRINTING

The article details the latest design and implementation of a stereolithography (SLA) based technique, Fluid Interface Supported Printing (FISP). The FISP technique involves printing from a thin resin layer above a static, immiscible support fluid. The support fluid prevents deflection of overhanging geometry by providing a buoyant force equal to that of the gravitational force due to the minute density difference between the support fluid and cured resin. Complex curing and shrinkage dynamics are a primary knowledge gap. A COMSOL multiphysics simulation model was developed to simulate the curing process, including volumetric light intensity and optimized parameters for chemical reaction kinetics. The article presents a pathway for further enhancing and validating the simulation model.Mechanical Engineerin

Understanding informal payments in health care: motivation of health workers in Tanzania

<p>Abstract</p> <p>Background</p> <p>There is growing evidence that informal payments for health care are fairly common in many low- and middle-income countries. Informal payments are reported to have a negative consequence on equity and quality of care; it has been suggested, however, that they may contribute to health worker motivation and retention. Given the significance of motivation and retention issues in human resources for health, a better understanding of the relationships between the two phenomena is needed. This study attempts to assess whether and in what ways informal payments occur in Kibaha, Tanzania. Moreover, it aims to assess how informal earnings might help boost health worker motivation and retention.</p> <p>Methods</p> <p>Nine focus groups were conducted in three health facilities of different levels in the health system. In total, 64 health workers participated in the focus group discussions (81% female, 19% male) and where possible, focus groups were divided by cadre. All data were processed and analysed by means of the NVivo software package.</p> <p>Results</p> <p>The use of informal payments in the study area was confirmed by this study. Furthermore, a negative relationship between informal payments and job satisfaction and better motivation is suggested. Participants mentioned that they felt enslaved by patients as a result of being bribed and this resulted in loss of self-esteem. Furthermore, fear of detection was a main demotivating factor. These factors seem to counterbalance the positive effect of financial incentives. Moreover, informal payments were not found to be related to retention of health workers in the public health system. Other factors such as job security seemed to be more relevant for retention.</p> <p>Conclusion</p> <p>This study suggests that the practice of informal payments contributes to the general demotivation of health workers and negatively affects access to health care services and quality of the health system. Policy action is needed that not only provides better financial incentives for individuals but also tackles an environment in which corruption is endemic.</p

Design of integrated inductances based on ferromagnetic LTCC layers

A compliant LTCC material system was developed which allows the integration of soft magnetic layers with a relative permeability ranging from 200 to 300. On this basis, ultra low profile inductances can be fabricated for miniaturized dc - dc converters. Inductances can be buried into the LTCC substrate to give more room for the semiconductor chips on top, or they can be fabricated as very small size planar inductances or arrays of inductances as surface mountable devices. In both manners, significant size and cost reductions are achievable. A number of toroidal and planar spiral coil designs were characterized and analyzed. At a coil diameter below 2.8 mm and a total thickness of 300 m, inductance values of up to 4.7 H were achieved at frequencies of up to 3 MHz and maximum currents of 800 mA. Q - factors were measured in the range between 100 KHz and 100 MHz with help of an impedance analyzer. The coil design was optimized in terms of via hole placement, inner and oute r coil diameter, and the number of ferromagnetic layers. All devices show a pronounced inductance maximum as a function of current which is typical for the ferrite material used. since all inductances use the same magnetic substrate and there is no physical separation, the effect of magnetic flux crowding and coupling between adjacent coils was additionally investigated. Based on the measured parameters, the saturation induction and magnetic losses as a function of frequency and magnetic flux of the ferrite tapes were calculated

MEDEA A209 - Integrated Components for Access Networks (ICFAN) Schlussbericht

Available from TIB Hannover: F01B649+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman