Chromatic confocal gauging for high precision dimensional metrology

Interest in the chromatic confocal microscope in the high precision dimensional metrology industry is growing rapidly. In fact, the chromatic confocal microscope offers a “stylus like” distance measurement applicable to various surface types. In addition, the chromatic confocal microscope can potentially compete in resolution with contact measurement probes, while significantly increasing the sampling rate to several kHz. Therefore, such technology is key to the Taylor Hobson Ltd. strategy. The work embodied in this thesis focuses on the design, development, and evaluation of a low cost and high resolution version of the chromatic confocal microscope. Both product are currently in pre-production phase. The low cost version the chromatic confocal microscope is designed to be a compact and cost effective system while exhibiting “state of the art” performances. In fact, the raw material cost of the system is below £500, this being achieved while exhibiting an optical head outer diameter of 8 mm, a working distance of more than 27 mm, and a resolution better than 100 nm over a measurement range exceeding 7 mm. The high resolution version of the chromatic confocal microscope is dedicated to precision. The aim of the design is to exhibit the highest achievable resolution while maintaining a measurement working distance exceeding 12 mm. By tailoring the chromatic dispersion to be appropriately low, a resolution of better than 10 nm is achieved. Both designs have been tailored within a few design cycles; this has been achieved through the development of two novel models, the spectral irradiance model and the measurement standard deviation model. The spectral irradiance model enables the analytical estimation of the chromatic confocal peak from only the optical parameters of the optical heads. Based on a geometric approach; this is more than 5 times more precise than the previously used model based on wave optics. Furthermore, by applying a fully integrated system design approach incorporating design, production, and test of optical systems, the resulting chromatic confocal system surpasses comparable commercially available chromatic confocal gauges in terms of cost, resolution, numerical aperture, range of measurement, and working distance. Such performance is further enhanced by the use of staircase diffractive surfaces. Staircase diffractive surfaces are special hybrid aspheric diffractive surfaces exhibiting insignificant manufacturing losses allowing the design to be only limited by the scalar diffraction theory used by ray tracing packages. In addition, staircase diffractive lenses permit the passively athermalisation of the optical head of the chromatic confocal microscope. The work encapsulated in this thesis extends the current understanding of the measurement environment impact on chromatic confocal gauges. This study includes the impact of the surface reflectivity, roughness, and slope onto the linearity of the chromatic confocal microscope. Using the previously described findings, methods to mitigate the linearity error induced by the surface roughness, reflectivity, and slope are presented and applied.Engineering and Physical Sciences Research Council (EPSRC) scholarshi

Speech output technologies in interventions for individuals with aphasia : a scoping review

Purpose: Due to the rapid advancements in computer technology, technology-based AAC interventions have become increasingly available for people with aphasia (PWA). Technology-based AAC interventions include speech generating devices (SGDs) and/or mobile technology applications or software programs that produce speech output upon selection of a message. The purpose of this scoping review is to outline the current research evidence related to the effectiveness of AAC interventions using speech output technologies for PWA; identify gaps in the current literature; and propose directions for future research. Methods: To be included in this review, studies had to meet the following inclusion criteria: (a) the study’s intervention variables were related to the implementation of AAC using SGDs and/or mobile technology applications or software programs that turn computers into SGDs; (b) the studies included dependent variables which related to a change in behavior observed secondary to AAC intervention using speech-output technologies (i.e., SGDs, AAC apps, talking word processors, etc.); (c) participants in the studies had a primary diagnosis of aphasia whose etiologies included, but were not limited to, stroke, TBI, and PPA (d) statistical data from group designs allowed for effect sizes to be calculated (i.e., Cohen’s d, Pearson’s product moment correlation coefficient r, partial eta-squared), and data from single-subject experimental designs allowed for Nonoverlap of All Pairs (NAP) to be calculated; (e) studies were published in peer reviewed journals, in English, and between the years 1990 and 2020. Results: Our search methods yielded 16 pre-experimental and experimental studies that met our inclusion criteria. Effect sizes for functional communication outcome measures as well as behaviors related to symbol identification, symbol combination, and navigation of the AAC system ranged from small to large for both single subject and group designs. Of the included experimental studies, only three were appraised as providing conclusive evidence. The remaining studies were appraised as providing preponderant (n = 2), suggestive (n = 2), and inconclusive (n = 2) evidence. Conclusion: Gaps in the research included limited data on generalization and maintenance across functional communication behaviors and communication environments. Future research must focus on discovering and understanding variables that lead to effective use of AAC strategies and techniques across communicative contexts and partners.Communication Sciences and Disorder

The Specific Growth Rate (SGR) Related to the Histology of Gonad and Liver of African Catfish (Clarias gariepinus) Supplemented with Curcumin and Thyroxine Hormone

This study used catfish Clarias gariepinus as an experimental animal, which given supplementation of curcumin and thyroxine hormone. The results showed that during the reproductive period there was an increase in body weight of female catfish in line with the development of the gonads. Through the histology of the gonads, it appeared that oocyte development occurs over time.  The results of liver histology showed a high activity of hepatocyte cells as indicated by the formation of vacuoles, as the storage site for vitellogenin, in their cytoplasm. Supplementation of curcumin and thyroxine was able to increase the specific growth rate of catfish, and the catfish group that given the combination treatment of curcumin supplementation (5 g.kg-1 of feed) with thyroxine hormone (0.1 mg.kg-1 of feed) showed the more optimal results

Production of Superior Pigs by Injecting the Sows with Gonadotropin Prior to Mating

Abstract. An experiment was conducted to produce superior pigs with improved growth phenotypes and survival during postnatal growth by injecting the sows with gonadotropin prior to mating.  The experiment consisted of 2 stages.  In the first stage, 12 sows were divided into 2 groups i.e., sows injected with NaCl0.95% as a control (NSO) and sows injected with PG600 (SO) prior to mating.  Parameters measured were growth phenotypes and survival at birth and during pre-weaning period.  In the second stage, 24 of weaned pigs (age 8 weeks) from the first stage were selected (6 males and 6 females from NSO group and 6 males and 6 females from SO group) to be used for measurement of growth performance.  The experimental pigs were raised and observed until the age of 28 weeks (7 month).  The body weights were measured monthly.  The results of the experiment showed that improvement of uterine environment by gonadotropin injection of the sows prior to mating dramatically improved birth weight with a very homogenous birth weight within litter size.  Improved birth weight and within-litter variation of birth weight improved pre-weaning growth performance and survival that finally dramatically increased weaning weight and total weight of weaned pigs per sow.  After weaning, pigs born to SO sows grew faster and had around 10 kg higher body weight as compared to control at the age of 7 month.   It was concluded that superior pigs could be produced by improving endogenous secretion of pregnant hormone during pregnancy. Key words: Birth weight, growth phenotypes, survival, prenatal growth, postnatal growth Abstrak. Penelitian ini dilakukan untuk menghasilkan anak-anak babi unggul dengan fenotipe pertumbuhan dan daya hidup yang lebih baik selama pertumbuhan pascalahir dengan cara menyuntik induk babi dengan gonadotropin sebelum pengawinan.  Penelitian terdiri atas dua tahapan.  Penelitian tahap pertama, 12 ekor induk babi dikelompokkan ke dalam 2 kelompok, 1) kelompok kontrol, yaitu induk yang disuntik dengan NaCl 0.95% (NSO) dan 2) kelompok yang disuntik dengan PG600 sebelum pengawinan (SO).  Parameter yang diukur ialah fenotipe pertumbuhan dan daya hidup anak pada saat lahir dan selama periode prasapih.  Tahap kedua, 24 anak babi lepas sapih dari percobaan tahap pertama (umur 8 minggu) dipilih (6 jantan dan 6 betinadari kelompok NSOdan 6 jantan dan 6 betina dari kelompok SO) untuk digunakan dalam pengukuran kinerja pertumbuhan pascasapih.  Babi percobaan dibesarkan dan diamati sampai umur 28 minggu (7 bulan).  Bobot badan diukur setiap bulan.  Hasil penelitian menunjukkan bahwa perbaikan lingkungan uterus dengan cara penyuntikan induk dengan gonadotropin sebelum pengawinan secara dramatis memperbaiki bobot lahir anak dengan bobot lahir per induk yang lebih seragam.  Perbaikan bobot lahir dan keseragaman bobot lahir memperbaiki kinerja pertumbuhan prasapih dan kelangsungan hidup anak yang pada akhirnya secara dramatis meningkatkan bobot sapih dan total bobot anak yang disapih per ekor induk.  Setelah penyapihan, anak babi yang dilahirkan oleh induk yang disuntik gonadotropin tumbuh lebih cepat dengan bobot badan yang lebih tinggi sekitar 10 kg dibandingkan dengan kontrol pada umur 7 bulan.  Disimpulkan bahwa anak babi unggul dapat dihasilkan melalui perbaikan sekresi endogen hormon kebuntingan selama kebuntingan. Kata kunci: Bobot lahir, fenotipe pertumbuhan, daya hidup, pertumbuhan prenatal, pertumbuhan pascalahi

Adjustable Functionalization of Hyper-Cross-Linked Polymers of Intrinsic Microporosity for Enhanced CO2 Adsorption and Selectivity over N2 and CH4

In this paper, we report the design, synthesis, and characterization of a series of hyper-cross-linked polymers of intrinsic microporosity (PIMs), with high CO2 uptake and good CO2/N2 and CO2/CH4 selectivity, which makes them competitive for carbon capture and biogas upgrading. The starting hydrocarbon polymers’ backbones were functionalized with groups such as −NO2, −NH2, and −HSO3, with the aim of tuning their adsorption selectivity toward CO2 over nitrogen and methane. This led to a significant improvement in the performance in the potential separation of these gases. All polymers were characterized via Fourier transform infrared (FTIR) spectroscopy and 13C solid-state NMR to confirm their molecular structures and isothermal gas adsorption to assess their porosity, pore size distribution, and selectivity. The insertion of the functional groups resulted in an overall decrease in the porosity of the starting polymers, which was compensated with an improvement in the final CO2 uptake and selectivity over the chosen gases. The best uptakes were achieved with the sulfonated polymers, which reached up to 298 mg g–1 (6.77 mmol g–1), whereas the best CO2/N2 selectivities were recorded by the aminated polymers, which reached 26.5. Regarding CH4, the most interesting selectivities over CO2 were also obtained with the aminated PIMs, with values up to 8.6. The reason for the improvements was ascribed to a synergetic contribution of porosity, choice of the functional group, and optimal isosteric heat of adsorption of the materials

Marine image pearls: Designed by man; created by nature

Over times immemorial, pearls have emerged as a symbol of perfec tion and of the highest spiritual ideals within most of the religions of the world. Pearls are also believed to possess certain physical properties that would prevent aging, ensure long life and also serve as an aphrodisiac

Metal-insulator-metal nanoresonators - Strongly confined modes for high surface sensitivity

Photonic and plasmonic refractive index sensors are able to detect increasingly smaller refractive index changes and concentrations of clinically relevant substances. They typically exploit optical resonances and aim to maximise the field overlap with the analyte in order to achieve high sensitivity. Correspondingly, they operate on the basis of maximizing the bulk sensitivity, which favours spatially extended modes. We note that this strategy, counter-intuitively, is not necessarily suitable for detecting biomolecules and one should focus on the surface sensitivity instead. Here, we show that by confining light tightly in metal-insulator-metal (MIM) nanoresonators, the surface sensitivity is significantly increased despite a clear decrease in bulk sensitivity. In particular, we experimentally show the operation of third order MIM resonators which support both extended surface plasmon polariton (SPP) modes and localized MIM modes. We are able to demonstrate that the MIM mode has a sensitivity of 55 nm/RIU to a 10 nm layer, which is approximately twice as high as that of the SPP mode. Overall, our work emphasizes the importance of the surface sensitivity over the more commonly used bulk sensitivity and it shows a novel approach for improving it. These insights are highly relevant for the design of next generation optical biosensors