Materials analysis of fluorocarbon films for MEMS applications

In this paper the results of the materials analysis of fluorocarbon (FC) films are presented. The properties of the fluorocarbon films are comparable to those of polytetrafluoroethylene (PTFE), better known under the trademarks such as teflon and fluon. The properties of PTFE are desirable for MEMS applications and enable new designs, new applications and new technological processing routes for microsystems. Therefore, FC films have a tremendous potential for MEMS applications. Furthermore, FC films can easily be deposited via spin coating, e-beam evaporation, in conventional reactive ion etchers and in plasma-enhanced deposition chambers using a carbonhydrotrifluoride plasma facilitating the use of the films for micro electro-mechanical structures. The films deposited in a reactive ion etcher are extremely chemical resistant. The X-ray photoelectron spectroscopy (XPS) analyses results are presente

Is maternity care in Scotland equitable? Results of a national maternity care survey

Objective High-quality maternity care is key to long-term improvements in population health. However, even within developed welfare systems, some mothers and babies experience poorer care and outcomes. This study aimed to explore whether women’s experiences of maternity care in Scotland differs by their physical or sociodemographic characteristics. Design Secondary analysis of the 2015 Scottish Maternity Care Experience Survey. The questionnaire was based on the Care Quality Commission English maternity survey. Setting National Health Service maternity care in Scotland. Participants The survey was distributed to 5025 women who gave birth in Scotland during February and March 2015 with 2036 respondents (41%). Main outcome measures The questionnaire explored aspects of care processes and interpersonal care experienced from the first antenatal contact (booking) to 6 weeks following the birth. The analysis investigated whether experiences were related to age, parity, deprivation, rurality, self-reported general health or presence of a health condition that limited daily activities. Analysis used mixed effect multilevel models incorporating logistic regression. Results There were associations between parity, age and deprivation with gestation at booking indicating that younger women, women from more deprived areas and multiparous women booked later. Women reporting generally poorer health were more likely to describe poorer care experiences in almost every domain including continuity, pain relief in labour, communication with staff, support and advice, involvement in decision making, confidence and trust and overall rating of care. Conclusions We found few differences in maternity care experience for women based on their physical or socioeconomic characteristics. Our findings indicate that maternity care in Scotland is generally equitable. However, the link between poorer general health after childbirth and poorer experience of maternity care is an important finding requiring further study

Multicomponent Approaches to Molecular Diversity & Complexity

Orru, R.V.A. [Promotor]Groen, M.B. [Promotor]Ruijter, E. [Copromotor

Characteristics of high quality ZnO thin films deposited by pulsed laser deposition

This paper show that under optimized deposition condition, films can be grown having a full width at half maximum (FWHM) value of the (002) x-ray diffraction (XRD) line a factor of 4 smaller than the previously published results using PLD and among the best reported so far by any technique. Under optimized conditions, c-axis oriented ZnO films having a FWHM value of the (002) XRD reflection line less than 15°, electrical resistivities around 5 × 10-2 Ω cm and optical transmittance higher than 85% in the visible region of the spectrum were obtained. Refractive index was around 1.98 and the Eg = 3.26 eV, values characteristic of very high quality ZnO thin films

Deemo: a new technology for the fabrication of microstructures

The recent innovations in dry etching make it a promising technology for the fabrications of micromoulds. The high aspect ratios, directional freedom, low roughness, high etch rates and high selectivity with respect to the mask material allow a versatile fabrication process of micromoulds for subsequent electroplating and embossing, as is demonstrated with the DEEMO process. DEEMO is an English acronym and stands for Dry Etching, Electroplating and Moulding

Demonstration of sustained and useful converter responses during balanced and unbalanced faults in microgrids

In large power grids where converter penetration is presently low and the network impedance is predominantly reactive, the required response from converters during faults is presently specified by phrases such as “maximum reactive output”. However, in marine and aero power systems most faults are unbalanced, the network impedance is resistive, and converter penetration may be high. Therefore a balanced reactive fault current response to an unbalanced fault may lead to over-voltages or over/under frequency events. Instead, this paper presents a method of controlling the converter as a balanced voltage source behind a reactance, thereby emulating the fault response of a synchronous generator (SG) as closely as possible. In this mode there is a risk of converter destruction due to overcurrent. A new way of preventing destruction but still providing fault performance as close to a SG as possible is presented. Demonstrations are presented of simulations and laboratory testing at the 10kVA 400V scale, with balanced and unbalanced faults. Currents can be limited to about 1.5pu while still providing appropriate unbalanced fault response within a resistive network

Integration of a mean-torque diesel engine model into a hardware-in-the-loop shipboard network simulation using lambda tuning

This study describes the creation of a hardware-in-the-loop (HIL) environment for use in evaluating network architecture, control concepts and equipment for use within marine electrical systems. The environment allows a scaled hardware network to be connected to a simulation of a multi-megawatt marine diesel prime mover, coupled via a synchronous generator. This allows All-Electric marine scenarios to be investigated without large-scale hardware trials. The method of closing the loop between simulation and hardware is described, with particular reference to the control of the laboratory synchronous machine, which represents the simulated generator(s). The fidelity of the HIL simulation is progressively improved in this study. First, a faster and more powerful field drive is implemented to improve voltage tracking. Second, the phase tracking is improved by using two nested proportional–integral–derivative–acceleration controllers for torque control, tuned using lambda tuning. The HIL environment is tested using a scenario involving a large constant-power load step. This provides a very severe test of the HIL environment, and also reveals the potentially adverse effects of constant-power loads within marine power systems