Non-contact measurement machine for freeform optics

The performance of high-precision optical systems using spherical optics is limited by aberrations. By applying aspherical and freeform optics, the geometrical aberrations can be reduced or eliminated while at the same time also reducing the required number of components, the size and the weight of the system. New manufacturing techniques enable creation of high-precision freeform surfaces. Suitable metrology (high accuracy, universal, non-contact, large measurement volume and short measurement time) is key in the manufacturing and application of these surfaces, but not yet available. In this thesis, the design, realization and testing of a new metrology instrument is described. This measurement machine is capable of universal, noncontact and fast measurement of freeform optics up to Ø500 mm, with an uncertainty of 30 nm (2s). A cylindrical scanning setup with an optical distance probe has been designed. This concept is non-contact, universal and fast. With a probe with 5 mm range, circular tracks on freeform surfaces can be measured rapidly with minimal dynamics. By applying a metrology frame relative to which the position of the probe and the product are measured, most stage errors are eliminated from the metrology loop. Because the probe is oriented perpendicular to the aspherical best-fit of the surface, the sensitivity to tangential errors is reduced. This allows for the metrology system to be 2D. The machine design can be split into three parts: the motion system, the metrology system and: the non-contact probe. The motion system positions the probe relative to the product in 4 degrees of freedom. The product is mounted on an air bearing spindle (??), and the probe is positioned over it in radial (r), vertical (z) and inclination (¿) direction by the R-stage, Z-stage and ¿- axis, respectively. The motion system provides a sub-micrometer repeatable plane of motion to the probe. The Z-stage is hereto aligned to a vertical plane of the granite base using three air bearings, to obtain a parallel bearing stage configuration. To minimize distortions and hysteresis, the stages have separate position and preload frames. Direct drive motors and high resolution optical scales and encoders are used for positioning. Mechanical brakes are applied while measuring a track, to minimize power dissipation and to exclude encoder, amplifier and EMC noise. The motors, brakes and weight compensation are aligned to the centres of gravity of the R and Zstage. Stabilizing controllers have been designed based on frequency response measurements. The metrology system measures the position of the probe relative to the product in the six critical directions in the plane of motion of the probe (the measurement plane). By focussing a vertical and horizontal interferometer onto the ¿-axis rotor, the displacement of the probe is measured relative to the reference mirrors on the upper metrology frame. Due to the reduced sensitivity in tangential direction at the probe tip, the Abbe criterion is still satisfied. Silicon Carbide is the material of choice for the upper metrology frame, due to its excellent thermal and mechanical properties. Mechanical and thermal analysis of this frame shows nanometer-level stabilities under the expected thermal loads. Simulations of the multi-probe method show capabilities of in process separation of the spindle reference edge profile and the spindle error motion with sub-nanometer uncertainty. The non-contact probe measures the distance between the ¿-axis rotor and the surface under test. A dual stage design is applied, which has 5 mm range, nanometer resolution and 5° unidirectional acceptance angle. This enables the R and Z-stage and ¿-axis to be stationary during the measurement of a circular track on a freeform surface. The design consists of a compact integration of the differential confocal method with an interferometer. The focussing objective is positioned by a flexure guidance with a voice coil actuator. A motion controller finds the surface and keeps the objective focused onto it with some tens of nanometers servo error. The electronics and software are designed to safely operate the 5 axes of the machine and to acquire the signals of all measurement channels. The electronics cabinet contains a real-time processor with many in and outputs, control units for all 5 axes, a safety control unit, a probe laser unit and an interferometry interface. The software consists of three main elements: the trajectory planning, the machine control and the data processing. Emphasis has been on the machine control, in order to safely validate the machine performance and perform basic data-processing. The performance of the machine assembly has been tested by stability, single track and full surface measurements. The measurements focus on repeatability, since this is a key condition before achieving low measurement uncertainty by calibration. The measurements are performed on a Ø100 mm optical flat, which was calibrated by NMi VSL to be flat within 7 nm rms. At standstill, the noise level of the metrology loop is 0.9 nm rms over 0.1 s. When measuring a single track at 1 rev/s, 10 revolutions overlap within 10 nm PV. The repeatability of three measurements of the flat, tilted by 13 µm, is 2 nm rms. The flatness measured by the uncalibrated machine matches the NMi data well. Ten measurements of the flat tilted by 1.6 mm repeat to 3.4 nm rms. A new non-contact measurement machine prototype for freeform optics has been developed. The characteristics desired for a high-end, single piece, freeform optics production environment (high accuracy, universal, non-contact, large measurement volume and short measurement time) have been incorporated into one instrument. The validation measurement results exceed the expectations, especially since they are basically raw data. Future calibrations and development of control and dataprocessing software will certainly further improve these results

NANOMEFOS (Nanometer Accuracy Non-contact Measurement of Free-form Optical Surfaces)

This paper describes a conceptual measurement machine design, aiming for universal and noncontact form measurement of free-form optical surfaces up to Ø 500 mm with an uncertainty of 30 nm (k = 2). This conceptual design is the result of a M.Sc. graduation assignment done within Eindhoven University of Technology (TU/e) in collaboration with TNO TPD. Recently a PhD study has started at TU/e called NANOMEFOS (Nanometer Accuracy Non-contact Measurement of Free-form Optical Surfaces), to further develop this concept. In this paper, first the requirements and current metrology methods with respect to these requirements will be discussed. Next, the machine concept and the calculation of the error budget will be explained. Finally, a short overview of the current design will be given

Patient, nursing and medical staff experiences and perceptions of the care of people with palliative esophagogastric cancer

Background: Esophagogastric cancer is the fifth most common malignancy and its incidence is increasing. The disease progresses quickly and five-year survival rates are poor. Treatment with palliative intent is provided for the majority of patients but there remains a lack of empirical evidence on the most effective service models to support esophagogastric cancer patients. Objectives: The overall objective of this systematic review was to synthesize the best available evidence on the experiences and perceptions of patients and health professionals with regard to the care of people diagnosed with palliative esophagogastric cancer. Inclusion criteria Types of participants: The review considered studies that included patients diagnosed with palliative esophagogastric cancer and any health professionals involved in the delivery of palliative care to this patient group in a hospital, home or community setting. Phenomena of interest: The review considered studies that investigated the experiences and perceptions of people diagnosed with palliative esophagogastric cancer and staff working with these people. Context: Studies that were carried out in any setting, including in-patient and outpatient areas, specialist cancer and non-specialist palliative care services and those were any patient were in receipt or had experiences of palliative care services were considered. All types of health practitioners delivering palliative care to esophagogastric cancer patients were considered. Types of studies: Studies that focused on qualitative data, including, but not limited to, designs such as phenomenology, grounded theory, ethnography, action research, feminist research and narrative approaches were considered. Mixed methods studies were considered in the review only if qualitative findings were reported separately. Search strategy: A three-step search strategy was utilized. A total 11 databases were searched for studies from 2000 onward, followed by hand searching of reference lists. Methodological quality: Methodological quality was assessed using the Joanna Briggs Institute Qualitative Assessment and Review Instrument critical appraisal tool (JBI-QARI). Data extraction: Qualitative findings were extracted using the JBI-QARI data extraction Instrument. Data synthesis: Qualitative research findings were pooled using a pragmatic meta-aggregative approach. Results: The review included two publications. There were 46 findings which were aggregated into four categories and one overall synthesized finding: “In addition to support for physical needs, patients need support that takes into account changing life situations to achieve the best quality of life.” Conclusions: The review shows that patients value services and support that addresses their complex, fluctuating and highly individual needs. No evidence was uncovered regarding how these services should be designed and delivered

NANOMEFOS (Nanometer Accuracy Non-contact Measurement of Free-form Optical Surfaces)

This paper describes a conceptual measurement machine design, aiming for universal and noncontact form measurement of free-form optical surfaces up to Ø 500 mm with an uncertainty of 30 nm (k = 2). This conceptual design is the result of a M.Sc. graduation assignment done within Eindhoven University of Technology (TU/e) in collaboration with TNO TPD. Recently a PhD study has started at TU/e called NANOMEFOS (Nanometer Accuracy Non-contact Measurement of Free-form Optical Surfaces), to further develop this concept. In this paper, first the requirements and current metrology methods with respect to these requirements will be discussed. Next, the machine concept and the calculation of the error budget will be explained. Finally, a short overview of the current design will be given

The complexity of shaping self-management in daily practice

_Background and context:_ Many countries are giving patients a more active role in health care, on both the individual and collective level. This paper focuses on one aspect of the participation agenda on the individual level: self-management. The paper explores self-management in practice, including the implications of the difficulties encountered. _Objective:_ to gain insight into the complexity of self-management practice. This is crucial for developing both self-management interventions and the participation policy agenda. _Methods:_ qualitative semi-structured interviews with experts (n=6) and patients with a chronic condition (n=20). _Results:_ in terms of level of involvement and type of activity, shaping self-management in practice depends on personal and social dynamics, patients’ ideas of the good life, and their interactions with care professionals. Clashes can arise when patients and professionals hold differing ideas, based on different values, about the level and type of patient involvement. _Discussion:_ The discussion on self-management should account for the fact that how we define self-management is very much a normative issue

The Effect of Carbohydrate Intake on Strength and Resistance Training Performance: A Systematic Review

High carbohydrate intakes are commonly recommended for athletes of various sports, including strength trainees, to optimize performance. However, the effect of carbohydrate intake on strength training performance has not been systematically analyzed. A systematic literature search was conducted for trials that manipulated carbohydrate intake, including supplements, and measured strength, resistance training or power either acutely or after a diet and strength training program. Studies were categorized as either (1) acute supplementation, (2) exercise-induced glycogen depletion with subsequent carbohydrate manipulation, (3) short-term (2–7 days) carbohydrate manipulation or (4) changes in performance after longer-term diet manipulation and strength training. Forty-nine studies were included: 19 acute, six glycogen depletion, seven short-term and 17 long-term studies. Participants were strength trainees or athletes (39 studies), recreationally active (six studies) or untrained (four studies). Acutely, higher carbohydrate intake did not improve performance in 13 studies and enhanced performance in six studies, primarily in those with fasted control groups and workouts with over 10 sets per muscle group. One study found that a carbohydrate meal improved performance compared to water but not in comparison to a sensory-matched placebo breakfast. There was no evidence of a dose-response effect. After glycogen depletion, carbohydrate supplementation improved performance in three studies compared to placebo, in particular during bi-daily workouts, but not in research with isocaloric controls. None of the seven short-term studies found beneficial effects of carbohydrate manipulation. Longer-term changes in performance were not influenced by carbohydrate intake in 15 studies; one study favored the higher- and one the lower-carbohydrate condition. Carbohydrate intake per se is unlikely to strength training performance in a fed state in workouts consisting of up to 10 sets per muscle group. Performance during higher volumes may benefit from carbohydrates, but more studies with isocaloric control groups, sensory-matched placebos and locally measured glycogen depletion are needed.publishedVersio

Development and performance demonstration of the NANOMEFOS non-contact measurement machine for freeform optics

This paper shows the machine concept, the realization and the test results of the completed NANOMEFOS non-contact measurement machine for freeform optics. The separate short metrology loop results in a stability at standstill of 0.9 nm rms over 0.1 s. Measurements of a tilted flat show a repeatability of 2-4 nm rms, depending on the applied tilt, and a flatness that agrees well with the NMi measurement