Post-deposition ageing reactions of plasma derived polyterpenol thin films

Owing to the structural flexibility, uncomplicated processing and manufacturing capabilities, plasma polymers are the subject of active academic as well as industrial research. Polymer thin films prepared from non-synthetic monomers combine desirable optical and physical properties with biocompatibility and environmental sustainability. However, the ultimate expediency and implementation of such materials will dependent on the stability of these properties under varied environmental conditions. Polyterpenol thin films were manufactured at different deposition powers. Under ambient conditions, the bulk of ageing occurred within first 150h after deposition and was attributed to oxidation and volumetric relaxation. Films observed for further 12 months showed no significant changes in thickness or refractive index. Thermal degradation behaviour indicated thermal stability increased for the films manufactured at higher RF powers. Annealing the films to 405°C resulted in full degradation, with retention between 0.29 and 0.99%, indicating films' potential as sacrificial material.

Optimal dynamic inversion-based semi-active control of benchmark bridge using MR dampers

A new two-stage state feedback control design approach has been developed to monitor the voltage supplied to magnetorheological (MR) dampers for semi-active vibration control of the benchmark highway bridge. The first stage contains a primary controller, which provides the force required to obtain a desired closed-loop response of the system. In the second stage, an optimal dynamic inversion (ODI) approach has been developed to obtain the amount of voltage to be supplied to each of the MR dampers such that it provides the required force prescribed by the primary controller. ODI is formulated by optimization with dynamic inversion, such that an optimal voltage is supplied to each damper in a set. The proposed control design has been simulated for both phase-I and phase-II study of the recently developed benchmark highway bridge problem. The efficiency of the proposed controller is analyzed in terms of the performance indices defined in the benchmark problem definition. Simulation results demonstrate that the proposed approach generally reduces peak response quantities over those obtained from the sample semi-active controller, although some response quantities have been seen to be increasing. Overall, the proposed control approach is quite competitive as compared with the sample semi-active control approach.

The study of oxidation state of manganese in lead oxyhalide glasses by optical spectroscopy

Abstaract is not available.

Impact of low temperature storage on active and storage forms of folate in choy sum (Brassica rapa subsp parachinensis)

Choy sum (Brassica rapa subsp. parachinensis) is a dark green leafy vegetable that contains high folate (vitamin B9) levels comparable to spinach. Folate is essential for the maintenance of human health and is obtained solely through dietary means. Analysis of the edible portion of choy sum by both microbiological assay and LC-MS/MS indicated that total folate activity remained significantly unchanged over 3 weeks storage at 4 degrees C. Inedible fractions consisted primarily of outer leaves, which showed signs of rotting after 14d, and a combination of rotting and yellowing after 21 d, contributing to 20% and 40% of product removal, respectively. Following deconjugation of the folate present in choy sum to monoglutamate and diglutamate derivatives, the principal forms (vitamers) of folate detected in choy sum were 5-methyltetrahydrofolate and 5-formyl tetrahydrofolate, followed by tetrahydrofolate (THF), 5,10-methenyl-THF, and 10-formyl folic acid. During storage, a significant decline in 5-formyl-THF was observed, with a slight but not significant increase in the combined 5-methyl-THF derivatives. The decline in 5-formyl-THF in relation to the other folate vitamers present may indicate that 5-formyl-THF is being utilised as a folate storage reserve, being interconverted to more metabolically active forms of folate, such as 5-methyl-THF. Although folate vitamer profile changed over the storage period, total folate activity did not significantly change. From a human nutritional perspective this is important, as while particular folate vitamers (e.g. 5-methyl-THF) are necessary for maintaining vital aspects of plant metabolism, it is less important to the human diet, as humans can absorb and interconvert multiple forms of folate. The current trial indicates that it is possible to store choy sum for up to 3 weeks at 4 degrees C without significantly affecting total folate concentration of the edible portion. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.

Realization of first order optical systems using thin lensest

A first order optical system is investigated in full generality within the context of wave optics. The problem is reduced to a study of the ray transfer matrices. The simplest such systems correspond to axially symmetric propagation. Realization of such systems by centrally located lenses separated by finite distances is studied. It is shown that, contrary to the commonly held view, the set of first order systems that can be realized using axially symmetric thin lenses exhausts the entire SL(2, R) group; at most three lenses are needed to realize any element of this group. In particular, the inverse of free propagation can be so realized. Among anisotropic systems it is again shown that every element of the lens group Sp(4, R) can be realized using a finite number of thin lenses.

Very-high-Q inductor simulation for active tuned filters

Abstract is not available.

Investigation of surface activity and photoinduced diffusion of metals in solution deposited amorphous films of As2S3

Surface activity of solution deposited (SD) amorphous films of As2S3 has been investigated. Silver and copper are readily deposited on such films from appropriate aqueous ionic solutions. The metals diffuse into the films upon irradiation with energetic photons. Structure and properties of SD films have been investigated using electron microscopy, optical spectroscopy and differential scanning calorimetry. The amorphous films tend to crystallize upon metal diffusion. The stability of amorphous films, the deposition of metals on their active surfaces and the photo-induced diffusion may all be attributed to the presence or production of charged defects in amorphous chalcogenide films.

Improved optical character recognition by matched filtering

The effectiveness of linear matched filters for improved character discrimination in presence of random noise and poorly defined characters has been investigated. We have found that although the performance of the filter in presence of random noise is reasonably good (16 dB gain in signal-to-noise-ratio) its performance is poor when the unknown character is distorted (linear shift and rotation).

Paraxial Maxwell beams: transformation by general linear optical systems

Extending the work of earlier papers on the relativistic-front description of paraxial optics and the formulation of Fourier optics for vector waves consistent with the Maxwell equations, we generalize the Jones calculus of axial plane waves to describe the action of the most general linear optical system on paraxial Maxwell fields. Several examples are worked out, and in each case it is shown that the formalism leads to physically correct results. The importance of retaining the small components of the field vectors along the axis of the system for a consistent description is emphasized.

Circulating concentrations of leptin, ovarian follicle number, and oocyte lipid content and active mitochondria, in Zebu crossbred cows maintained on standard or improved nutrition

Zebu (Bos indicus) crossbred beef cows (Droughtmaster) were maintained long-term (16 months) on standard nutrition (SN) or improved nutrition (IN). Cows on IN had better body condition and greater (P<0.05) circulating concentrations of leptin than cows on SN (0.7±0.1n/ml and 1.7±0.1n/ml, respectively). There were no outstanding differences between SN and IN cows in basal number of ovarian follicles (≤4mm, 5-8mm, and≥9mm) and there were also no differences in number of oocytes recovered by oocyte pick-up. Cows on IN had a greater (P<0.05) number of total follicles after stimulation with FSH than cows on SN. Oocytes from cows on IN had greater (P<0.05) lipid content than cows on SN (-0.23±0.16 and 0.20±0.18 arbitrary units, respectively) and oocytes of the former cows also tended to have more active mitochondria, although this was not significant. Cows on IN showed a positive relationship (R2=0.31, P<0.05) between plasma leptin and oocyte lipid content. Lipids are utilized by oocytes during high energy consumptive processes including fertilization and early cleavage. The greater lipid content of oocytes from IN cows could therefore confer a reproductive advantage. The present study has shown relationships between nutrition, body condition, circulating leptin, and oocyte lipid content, but a clear cause-and-effect requires further investigation in the cow. © 2013 Elsevier B.V.

Stiffer Optical Tweezers through Real-Time Feedback Control

This thesis integrates real-time feedback control into an optical tweezers instrument. The goal is to reduce the variance in the trapped bead s position, -effectively increasing the trap stiffness of the optical tweezers. Trap steering is done with acousto-optic deflectors and control algorithms are implemented with a field-programmable gate array card. When position clamp feedback control is on, the effective trap stiffness increases 12.1-times compared to the stiffness without control. This allows improved spatial control over trapped particles without increasing the trapping laser power.

Stretching single DNA-molecules with temperature-stabilized optical tweezers

This thesis consists of two parts; in the first part we performed a single-molecule force extension measurement with 10kb long DNA-molecules from phage-λ to validate the calibration and single-molecule capability of our optical tweezers instrument. Fitting the worm-like chain interpolation formula to the data revealed that ca. 71% of the DNA tethers featured a contour length within ±15% of the expected value (3.38 µm). Only 25% of the found DNA had a persistence length between 30 and 60 nm. The correct value should be within 40 to 60 nm. In the second part we designed and built a precise temperature controller to remove thermal fluctuations that cause drifting of the optical trap. The controller uses feed-forward and PID (proportional-integral-derivative) feedback to achieve 1.58 mK precision and 0.3 K absolute accuracy. During a 5 min test run it reduced drifting of the trap from 1.4 nm/min in open-loop to 0.6 nm/min in closed-loop.

Multiangular Spectrometry and Optical Properties of Debris Covered Surfaces

Due to the recent development in CCD technology aerial photography is now slowly changing from film to digital cameras. This new aspect in remote sensing allows and requires also new automated analysis methods. Basic research on reflectance properties of natural targets is needed so that computerized processes could be fully utilized. For this reason an instrument was developed at Finnish Geodetic Institute for measurement of multiangular reflectance of small remote sensing targets e.g. forest understorey or asphalt. Finnish Geodetic Institute Field Goniospectrometer (FiGIFiGo) is a portable device that is operated by 1 or 2 persons. It can be reassembled to a new location in 15 minutes and after that a target's multiangular reflectance can be measured in 10 - 30 minutes (with one illumination angle). FiGIFiGo has effective spectral range approximately from 400 nm to 2000 nm. The measurements can be made either outside with sunlight or in laboratory with 1000 W QTH light source. In this thesis FiGIFiGo is introduced and the theoretical basis of such reflectance measurements are discussed. A new method is introduced for extraction of subcomponent proportions from reflectance of a mixture sample, e.g. for retrieving proportion of lingonberry's reflectance in observation of lingonberry-lichen sample. This method was tested by conducting a series of measurements on reflectance properties of artificial samples. The component separation method yielded sound results and brought up interesting aspects in targets' reflectances. The method and the results still need to be verified with further studies, but the preliminary results imply that this method could be a valuable tool in analysis of such mixture samples.

Active vibration suppression of non-linear beams using optimal dynamic inversion

Euler–Bernoulli beams are distributed parameter systems that are governed by a non-linear partial differential equation (PDE) of motion. This paper presents a vibration control approach for such beams that directly utilizes the non-linear PDE of motion, and hence, it is free from approximation errors (such as model reduction, linearization etc.). Two state feedback controllers are presented based on a newly developed optimal dynamic inversion technique which leads to closed-form solutions for the control variable. In one formulation a continuous controller structure is assumed in the spatial domain, whereas in the other approach it is assumed that the control force is applied through a finite number of discrete actuators located at predefined discrete locations in the spatial domain. An implicit finite difference technique with unconditional stability has been used to solve the PDE with control actions. Numerical simulation studies show that the beam vibration can effectively be decreased using either of the two formulations.

Can Nano Silicon Be Made Optically Active?

There has been a lot of effort to make Silicon optically active. In this work we examine two methods of generating nanocrystals of Silicon from bulk fragments. This approach of ours allows us to play with the shape of the nanocrystals and therefore the degeneracy of the conduction band minimum. We go on to examine whether similar sized particles with different shapes have the same physical properties, and finally whether Silicon may be rendered optically active by this route. While we do find that similar sized particles with different shapes may have different band gaps, this route of modifying the degeneracy of the conduction band minimum makes nano Si slightly optically active.