Broadband photon time of flight spectroscopy: advanced spectroscopic analysis for ensuring safety and performance of pharmaceutical tablets

We report on extended spectroscopic analysis of pharmaceutical tablets performed with broadband photon time-of-flight absorption/scaring spectroscopy. Precise monitoring of absorption and scattering spectra enables cost-efficient monitoring of key safety and performance parameters of the drugs

Wide-bandwidth diffused optical spectroscopy for pharmaceutical characterization

We report on considerable improvement in measurements precision of the ultra broadband photon time of flight absorption/scattering spectrometer. We illustrate outstanding performance of the instrument by performing highly precise evaluation of the chemical composition of pharmaceuticals

Transscleral visible/near-infrared spectroscopy for quantitative assessment of melanin in a uveal melanoma phantom of ex vivo porcine eyes

Optical spectroscopy has been used as a supplement to conventional techniques for analyzing and diagnosing cancer in many human organs. Because ocular tumors may be characterized by their different melanin content, we investigated the feasibility of using transscleral visible/near-infrared spectroscopy (Vis/NIRS) to estimate the quantity of melanin in a novel uveal melanoma phantom of ex vivo porcine eyes. The phantoms were made by injecting a freshly prepared suspension of 15% (wt/vol) gelatin, 10 mg/ml titanium dioxide (TiO2), and natural melanin, isolated from the ink sac of cuttlefish (Sepia officinalis), into the suprachoroidal space of 30 enucleated porcine eyes. The melanin concentrations used were 1 mg/ml, 2 mg/ml, and 3 mg/ml, with 10 eyes in each group. After gelation, the size and location of the phantoms were documented by B-scan ultrasonography and transillumination. Vis/NIRS recordings, covering the wavelength region from 550 to 1000 nm, were performed with two optical fibers separated by 6 mm to deliver and collect the light through the sclera. During all measurements, the exact pressure exerted by the fiber probe on the scleral surface was monitored by placing the eye on an electronic scale. Transscleral Vis/NIRS was performed across the phantom inclusion, as well as on the opposite (normal) side of each eye. A total of three consecutive measurements were carried out alternately on each side of the globe. The spectral data were analyzed using partial least squares regression. In the melanin concentration groups of 1 mg/ml (n = 10), 2 mg/ml (n = 10), and 3 mg/ml (n 10), the largest basal phantom diameters (mean +/- SD) were 14.9 +/- 1.6 mm, 14.6 +/- 1.5 mm, and 14.3 +/- 1.0 mm, respectively (p > 0.05). The largest phantom thicknesses (mean +/- SD) were 4.0 +/- 0.5 mm, 4.4 +/- 0.7 mm, and 4.5 +/- 0.5 mm, respectively (p > 0.05). Statistical regression modeling of the Vis/NIRS data revealed that it was possible to correctly classify the phantoms according to their melanin concentrations in 84.4% of cases. The correct classification rate for phantoms with the lowest (1 mg/ml) and highest (3 mg/ml) melanin concentrations was 99.2%. The study demonstrates that transscleral Vis/NIRS is a feasible and accurate method for predicting the content of melanin in choroidal lesions. (C) 2009 Elsevier Ltd. All rights reserved

Puoliaktiivisen jousituksen laajentaminen tieprofiilia ennakoivaksi

Generally, the design of a suspension system is always a compromise between vehicle handling and driving comfort. A semi-active suspension system offers a possibility to overcome this trade-off due to the nature and controllability of the system. A road profile preview is a look-ahead preview which is made possible with modern camera technology. The conventional semi-active suspension system damping is controlled in order to achieve optimal settings only for current conditions. By knowing the road profile beforehand, the suspension system could not only be adjusted, but proactively set to fit the current and oncoming driving events. This thesis acts as one of the first steps of a research project to examine the viability of including road profile preview to the semi-active suspension control. This work focuses on examining ways to integrate the preview signal to an existing Skyhook-controlled semi-active suspension damping system. An important part of this thesis is to develop the base control further without significant modifications in the core controller in order to maintain the robustness and stability of the original control. The existing, continuously controlled damping controller is used as a basis for the control system development. The thesis consists of model-in-the-loop simulations which are carried out in a Matlab/Simulink environment, where the development and testing of the system is executed as well. The simulations are carried out with the help of a multi-body vehicle model veDYNA. In order to apply the preview feature, two approaches are introduced. The first approach includes a simplified full vehicle model in order to continuously control the suspension system damping. The second approach concentrates on enhancing the system performance based on detected single events. The simulation results show that by maintaining the base control, the continuous preview approach provides only moderate improvements, if at all. Nevertheless, focusing on the detection and classification of single events seems to offer great potential for improvement. The event based approach offers an easily applicable, adjustable and realizable way to improve the performance of the semi-active suspension.Ajoneuvon jousituksen suunnittelu ja toteuttaminen on tavallisesti kompromissi ajoneuvon hallittavuuden ja ajomukavuuden suhteen. Puoliaktiivisessa jousituksessa vaimentimia säätämällä voidaan näitä vastakkaisia ominaisuuksia parantaa yhtäaikaisesti. Perinteinen puoliaktiivinen jousitus voidaan ajon aikana säätää ihanteelliseksi tilanteen mukaan. Ennakoivalla jousituksella voidaan ajonaikaisen säädön lisäksi huomioida tuleva ajotilanne lähestyvää tieprofiilia tarkkailemalla. Ennakointi voidaan toteuttaa nykyaikaisen kameratekniikan avulla. Tämä diplomityö on ennakoivan jousituksen käyttöönottoon liittyvän tutkimusprojektin ensimmäinen vaihe, jonka tavoitteena on tutkia ennakoivan puoliaktiivisen jousituksen hyötyjä ja toteuttamiskelpoisuutta. Tässä työssä keskitytään tutkimaan tapoja, joilla optiselta sensorilta saatava tieprofiili-tieto voidaan yhdistää puoliaktiivisen jousitusjärjestelmään, jota ohjataan Skyhook-periaatteen mukaan. Työn olennainen osa on käytössä olevan vaimentimenohjauksen edelleen kehittäminen ennakoivalle jousitukselle soveltuvaksi. Työn lähtökohtana on nykyinen jatkuvatoimisesti säädettävä vaimentimien ohjausjärjestelmä, jonka keskeisen ohjausstrategian muokkaaminen ei ole toivottavaa. Työ koostuu simulaatioista, jotka suoritettiin Matlab/Simulink-ympäristössä, jossa myös järjestelmän kehittäminen ja testaaminen suoritettiin. Ajoneuvosimulaatiot suoritettiin ajoneuvon dynaamiseen simulointiin kehitetyn veDYNA-monikappalemallin avulla. Ennakoivan ominaisuuden käyttöönottamista ja soveltamista varten tutkittiin kahta erilaista lähestymistapaa. Ensimmäisessä lähestymistavassa sovellettiin yksinkertaistettua ennakoivaa ajoneuvomallia, jonka avulla veDYNAmallin jousitusta ohjattiin jatkuvatoimisena. Toisessa lähestymistavassa jousituksen suorituskykyä pyrittiin parantamaan erottelemalla havaitut yksittäiset tieprofiilin muutokset ja soveltamalla ennakoivaa ohjausta vain yksittäistapauksiin. Simulointitulokset osoittivat, että jatkuvatoiminen ennakointi mahdollistaa vain kohtalaisia etuja tavanomaiseen järjestelmään nähden, kun alkuperäinen vaimentimien ohjausperiaate säilytettiin. Sen sijaan keskittymällä yksittäisten tieprofiilin äkillisten muutosten tunnistamiseen, voidaan nykyistä vaimentimien ohjausta tehostaa ja näin ollen parantaa ajoneuvon jousituksen suorituskykyä. Ennakoiva ja vain yksittäistapauksiin keskittyvä lisäosa voidaan helposti liittää nykyiseen ohjausjärjestelmään ilman suuria muutoksia

Near-infrared photon time-of-flight spectroscopy of turbid materials up to 1400 nm

Photon time-of-flight spectroscopy (PTOFS) is a powerful tool for analysis of turbid materials. We have constructed a time-of-flight spectrometer based on a supercontinuum fiber laser, acousto-optical tunable filtering, and an InP/InGaAsP microchannel plate photomultiplier tube. The system is capable of performing PTOFS up to 1400 nm, and thus covers an important region for vibrational spectroscopy of solid samples. The development significantly increases the applicability of PTOFS for analysis of chemical content and physical properties of turbid media. The great value of the proposed approach is illustrated by revealing the distinct absorption features of turbid epoxy resin. Promising future applications of the approach are discussed, including quantitative assessment of pharmaceuticals, powder analysis, and calibration-free near-infrared spectroscopy