Fluorescence Spectroscopy and Chemometrics in the Food Classification − a Review
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Comparison of Life-Cycle Analyses of Compact Fluorescent and Incandescent Lamps Based on Rated Life of Compact Fluorescent Lamp
Comparison of Life-Cycle Analyses of Compact Fluorescent and Incandescent Lamps Based on Rated Life of Compact Fluorescent Lamp Laurie Ramroth Rocky Mountain Institute February 2008 Image: Compact Fluorescent Lamp. From Mark Stozier on istockphoto. Abstract This paper addresses the debate over compact fluorescent lamps (CFLs) and incandescents through life-cycle analyses (LCA) conducted in the SimaPro1 life-cycle analysis program. It compares the environmental impacts of providing a given amount of light (approximately 1,600 lumens) from incandescents and CFLs for 10,000 hours. Special attention has been paid to recently raised concerns regarding CFLs—specifically that their complex manufacturing process uses so much energy that it outweighs the benefits of using CFLs, that turning CFLs on and off frequently eliminates their energy-efficiency benefits, and that they contain a large amount of mercury. The research shows that the efficiency benefits compensate for the added complexity in manufacturing, that while rapid on-off cycling of the lamp does reduce the environmental (and payback) benefits of CFLs they remain a net “win,” and that the mercury emitted over a CFL’s life—by power plants to power the CFL and by leakage on disposal—is still less than the mercury that can be attributed to powering the incandescent. RMI: Life Cycle of CFL and Incandescent 2 Heading Page Introduction................................................................................................................... 5 Background................................................................................................................... -
Fluorescent Light-Emitting Diode (LED) Microscopy for Diagnosis of Tuberculosis
Fluorescent light-emitting diode (LED) microscopy for diagnosis of tuberculosis —Policy statement— March 2010 Contents Abbreviations Executive summary 1. Background 2. Evidence for policy formulation 2.1 Synthesis of evidence 2.2 Management of declarations of interest 3. Summary of results 4. Policy recommendations 5. Intended audience References Abbreviations CI confidence interval GRADE grades of recommendation assessment, development and evaluation LED light-emitting diode STAG-TB Strategic and Technical Advisory Group for Tuberculosis TB tuberculosis WHO World Health Organization Executive summary Conventional light microscopy of Ziehl-Neelsen-stained smears prepared directly from sputum specimens is the most widely available test for diagnosis of tuberculosis (TB) in resource-limited settings. Ziehl-Neelsen microscopy is highly specific, but its sensitivity is variable (20–80%) and is significantly reduced in patients with extrapulmonary TB and in HIV-infected TB patients. Conventional fluorescence microscopy is more sensitive than Ziehl-Neelsen and takes less time, but its use has been limited by the high cost of mercury vapour light sources, the need for regular maintenance and the requirement for a dark room. Light-emitting diodes (LED) have been developed to offer the benefits of fluorescence microscopy without the associated costs. In 2009, the evidence for the efficacy of LED microscopy was assessed by the World Health Organization (WHO), on the basis of standards appropriate for evaluating both the accuracy and the effect of new TB diagnostics on patients and public health. The results showed that the accuracy of LED microscopy was equivalent to that of international reference standards, it was more sensitive than conventional Ziehl-Neelsen microscopy and it had qualitative, operational and cost advantages over both conventional fluorescence and Ziehl- Neelsen microscopy. -
Introduction 1
1 1 Introduction . ex arte calcinati, et illuminato aeri [ . properly calcinated, and illuminated seu solis radiis, seu fl ammae either by sunlight or fl ames, they conceive fulgoribus expositi, lucem inde sine light from themselves without heat; . ] calore concipiunt in sese; . Licetus, 1640 (about the Bologna stone) 1.1 What Is Luminescence? The word luminescence, which comes from the Latin (lumen = light) was fi rst introduced as luminescenz by the physicist and science historian Eilhardt Wiede- mann in 1888, to describe “ all those phenomena of light which are not solely conditioned by the rise in temperature,” as opposed to incandescence. Lumines- cence is often considered as cold light whereas incandescence is hot light. Luminescence is more precisely defi ned as follows: spontaneous emission of radia- tion from an electronically excited species or from a vibrationally excited species not in thermal equilibrium with its environment. 1) The various types of lumines- cence are classifi ed according to the mode of excitation (see Table 1.1 ). Luminescent compounds can be of very different kinds: • Organic compounds : aromatic hydrocarbons (naphthalene, anthracene, phenan- threne, pyrene, perylene, porphyrins, phtalocyanins, etc.) and derivatives, dyes (fl uorescein, rhodamines, coumarins, oxazines), polyenes, diphenylpolyenes, some amino acids (tryptophan, tyrosine, phenylalanine), etc. + 3 + 3 + • Inorganic compounds : uranyl ion (UO 2 ), lanthanide ions (e.g., Eu , Tb ), doped glasses (e.g., with Nd, Mn, Ce, Sn, Cu, Ag), crystals (ZnS, CdS, ZnSe, CdSe, 3 + GaS, GaP, Al 2 O3 /Cr (ruby)), semiconductor nanocrystals (e.g., CdSe), metal clusters, carbon nanotubes and some fullerenes, etc. 1) Braslavsky , S. et al . ( 2007 ) Glossary of terms used in photochemistry , Pure Appl. -
Photodegradation and Characterization of Poly(Ethylene Oxide) / Montmorillonite Composite Films
ECCM15 - 15 TH EUROPEAN CONFERENCE ON COMPOSITE MATERIALS, Venice, Italy, 24-28 June 2012 PHOTODEGRADATION AND CHARACTERIZATION OF POLY(ETHYLENE OXIDE) / MONTMORILLONITE COMPOSITE FILMS Patrícia C. Lombardo 1*, Alessandra L. Poli 1, Miguel G. Neumann 1, Carla C. Schmitt Cavalheiro 1 1Instituto de Química de São Carlos, Departmento de Físico Química, Universidade de São Paulo, Address Av. Trabalhador São-Carlense, 400 CP 780 São Carlos, SP CEP 13560-970 *[email protected] Keywords: Poly(ethylene oxide), montmorillonite, photodegradation Abstract Poly(ethylene oxide) (PEO) composites with different concentrations of SWy-1 montmorillonite clay were prepared by solution intercalation method. Thin films of composites obtained by solvent evaporation were exposed to UV-irradiation. The photodegradation was monitored by FTIR and the chain scission reaction was confirmed by measurement of average molecular weights using size exclusion chromatography (SEC) method. The rate of oxidation of PEO was much faster than that of composites (PEO/SWy-1). The SWy-1 clay can be considered as stabilizer against UV irradiation. The stabilization mode of the clay may be explained on the ability of SWy-1 not only scatter the incident light but also to absorb the UV light instead of the PEO, thus minimizing the degradation rate of composites. 1 Introduction Polymer-clay nanocomposites are a new class of materials derivate of clay nanoparticles dispersed in the polymer matrix and have at least one of its dimensions in the nanometer range. The polymer-clay nanocomposites can provide, at very low silicate contents, improvements in physicals, chemicals and mechanicals properties [1],[2] . When preparing a polymer-clay nanocomposite, the most commonly used clay is montmorillonite (MMT). -
Spatially Resolved Characterization of Cellulose Nanocrystal– Polypropylene Composite by Confocal Raman Microscopy
Spatially Resolved Characterization of Cellulose Nanocrystal– Polypropylene Composite by Confocal Raman Microscopy Umesh P. Agarwal,* Ronald Sabo, Richard S. Reiner, Craig M. Clemons, Alan W. Rudie USDA FS, Forest Products Laboratory, Madison, WI 53726 USA Raman spectroscopy was used to analyze cellulose nanocrystal (CNC) The CNCs can be incorporated as the load-bearing –polypropylene (PP) composites and to investigate the spatial distribution component in composites to enhance the properties of synthetic of CNCs in extruded composite filaments. Three composites were made and other polymer matrices. This will give rise to composites from two forms of nanocellulose (CNCs from wood pulp and the nano- with improved strength. Obtaining information on composition scale fraction of microcrystalline cellulose) and two of the three and structure of the CNC composite is essential for correlating composites investigated used maleated PP as a coupling agent. Raman maps, based on cellulose and PP bands at 1098 and 1460 cmÀ1, structure to mechanical properties. Research investigations are respectively, obtained at 1 lm spatial resolution showed that the CNCs needed to understand the physicochemical aspects of the were aggregated to various degrees in the PP matrix. Of the three CNCs, the polymer matrix, and their interactions. This is composites analyzed, two showed clear existence of phase-separated extremely valuable because such findings will allow new regions: Raman images with strong PP and absent/weak cellulose or vice experimental strategies for optimizing composite processing versa. For the third composite, the situation was slightly improved but a and production. In the present investigation, composites of PP clear transition interface between the PP-abundant and CNC-abundant containing 2 wt. -
Degradation of Polymer/Substrate Interfaces – an Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Approach
Degradation of polymer/substrate interfaces – an attenuated total reflection Fourier transform infrared spectroscopy approach THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Arijit Ghosh, B.Sc., M.Sc. Graduate Program in Chemistry The Ohio State University 2010 Master's Examination Committee: Heather C. Allen, Advisor Joshua E. Goldberger Gerald S. Frankel Copyright by Arijit Ghosh 2010 Abstract Organic coatings are extensively applied to protect metal structures from corrosion related damage. The durability of such polymer coated adhesively bonded joint structures depends upon the stability of the interfaces between the polymer and the substrate it is coated on. It is economically important to have a thorough understanding of how such interfaces react to a variety of aggressive media that are relevant to real life scenarios. In this thesis, attenuated total reflection Fourier transform infrared (ATR- FTIR) spectroscopy has been used to detect changes at the interfaces between poly (vinyl butyral-co-vinyl alcohol-co-vinyl acetate) (PVB) and ZnSe upon exposure to ozone, humidity and UV-B light. Also, the response of PVB-aluminum interfaces to liquid water has been studied and compared with the same for eponol (epoxy resin, diglycidyl ether of bisphenol A)-aluminum interfaces. In the presence of ozone, humidity and UV-B radiation, an increase in carbonyl group intensity was observed at the PVB-ZnSe interface indicating structural degradation of the polymer near the interface. However, such changes were not observed when PVB coated ZnSe samples were exposed to moisture and UV-B light in the absence of ozone showing that ozone is responsible for the observed structural deterioration. -
VASILIS G. GREGORIOU, Ph.D. Director and Chairman of the Board
VASILIS G. GREGORIOU, Ph.D. VASILIS G. GREGORIOU, Ph.D. Director and Chairman of the Board National Hellenic Research Foundation (NHRF) 48 Vassileos Constantinou Avenue 11635 Athens, Greece Tel.: +30 210.72.73.500 Fax. +30 210.72.46.618 PUBLICATIONS I. ΒOOKS 1. “Vibrational Spectroscopy of Biomolecules and Polymers” V.G. Gregoriou and M. Braiman, Editors, Taylor & Francis Co, New York, NY, (2006). 2. “Polymer Spectroscopy” V.G. Gregoriou Editor, Wiley-VCH, Weinheim, Germany (2004). 3. “Modern Infrared Spectroscopy: Principles and Applications” A.A. Christy, Y. Ozaki, and V.G. Gregoriou, Elsevier Science, Amsterdam, the Netherlands (2001). II. CHAPTERS IN BOOKS 1. “Fourier Transform Infrared Spectroscopy” V.G. Gregoriou and S.E. Rodman in “Characterization of Materials” J. Wiley & Sons, New York, NY (2004). 2. “Study of the Viscoelastic Behavior of Liquid Crystalline Polyurethanes Using Static and Dynamic FT-IR Spectroscopy” V.G. Gregoriou, S.E. Rodman, B.R. Nair and P.T. Hammond, in “Vibrational Spectroscopy of Polymers and Biomolecules” V.G. Gregoriou and M. Braiman Editors, Marcel Dekker, New York, NY p. 1-34 (2006). 3. “Vibrational Spectroscopy of Thin Organic Films” V.G. Gregoriou, and S.E. Rodman, in “Handbook of Vibrational Spectroscopy” P.R. Griffiths and J. Chalmers Editors, J. Wiley & Sons, New York, N.Y. Vol. 4, p. 2670-2693 (2002). Page 1 of 25 VASILIS G. GREGORIOU, Ph.D. 4. “Infrared Spectroscopy of Polymers” V.G. Gregoriou, in “Applied Polymer Science, 21rst Century”, C.W. Craver and J.D. Johnson, Editors, Elsevier Science, Amsterdam, The Netherlands, Chapter 35, p. 709 (2000). 5. “Dynamic Fourier Transform Infrared Spectroscopy of Liquid Crystals and Polymer Films” V.G. -
Characterisation of a Deep-Ultraviolet Light-Emitting Diode Emission Pattern Via Fluorescence
Characterisation of a deep-ultraviolet light-emitting diode emission pattern via fluorescence Mollie McFarlane* and Gail McConnell1 *[email protected] 1Department of Physics, University of Strathclyde, SUPA, Glasgow, U.K. November 2019 Abstract Recent advances in LED technology have allowed the development of high-brightness deep- UV LEDs with potential applications in water purification, gas sensing and as excitation sources in fluorescence microscopy. The emission pattern of an LED is the angular distribution of emission intensity and can be mathematically modelled or measured using a camera, although a general model is difficult to obtain and most CMOS and CCD cameras have low sensitivity in the deep-UV. We report a fluorescence-based method to determine the emission pattern of a deep-UV LED, achieved by converting 280 nm radiation into visible light via fluorescence such that it can be detected by a standard CMOS camera. We find that the emission pattern of the LED is consistent with the Lambertian trend typically obtained in planar LED packages to an accuracy of 99.6%. We also demonstrate the ability of the technique to distinguish between LED packaging types. arXiv:1911.11669v1 [physics.ins-det] 26 Nov 2019 1 1 Introduction Recent developments in light-emitting diode (LED) technology have produced deep-ultraviolet alu- minium gallium nitride (AlGaN) LEDs with wavelengths ranging between 220-280 nm emitting in the 100 mW range [1]. These LEDs have applications in sterilisation, water purification [2] and gas-sensing [3]. Deep-UV LEDs also have potential applications as excitation sources in fluorescence microscopy. In particular, 280 nm LEDs have an electroluminescence spectrum which overlaps well with the excitation spectrum of many fluorophores including semiconductor quantum dots, aromatic amino acids tryptophan and tyrosine [4] and even standard dyes such as eosin, rhodamine and DAPI [5] [6]. -
Exterior Lighting Guide for Federal Agencies
EXTERIOR LIGHTING GUIDE FOR FederAL AgenCieS SPONSORS TABLE OF CONTENTS The U.S. Department of Energy, the Federal Energy Management Program, page 02 INTRODUctiON page 44 EMERGING TECHNOLOGIES Lawrence Berkeley National Laboratory (LBNL), and the California Lighting Plasma Lighting page 04 REASONS FOR OUTDOOR Technology Center (CLTC) at the University of California, Davis helped fund and Networked Lighting LiGHtiNG RETROFitS create the Exterior Lighting Guide for Federal Agencies. Photovoltaic (PV) Lighting & Systems Energy Savings LBNL conducts extensive scientific research that impacts the national economy at Lowered Maintenance Costs page 48 EXTERIOR LiGHtiNG RETROFit & $1.6 billion a year. The Lab has created 12,000 jobs nationally and saved billions of Improved Visual Environment DESIGN BEST PRActicES dollars with its energy-efficient technologies. Appropriate Safety Measures New Lighting System Design Reduced Lighting Pollution & Light Trespass Lighting System Retrofit CLTC is a research, development, and demonstration facility whose mission is Lighting Design & Retrofit Elements page 14 EVALUAtiNG THE CURRENT to stimulate, facilitate, and accelerate the development and commercialization of Structure Lighting LIGHtiNG SYSTEM energy-efficient lighting and daylighting technologies. This is accomplished through Softscape Lighting Lighting Evaluation Basics technology development and demonstrations, as well as offering outreach and Hardscape Lighting Conducting a Lighting Audit education activities in partnership with utilities, lighting -
A Statistical Analysis on the Effect of Antioxidants on the Thermal-Oxidative Stability of Commercial Mass- and Emulsion-Polymerized ABS
polymers Article A Statistical Analysis on the Effect of Antioxidants on the Thermal-Oxidative Stability of Commercial Mass- and Emulsion-Polymerized ABS Rudinei Fiorio 1,* , Dagmar R. D’hooge 2,3,* , Kim Ragaert 1 and Ludwig Cardon 1 1 Centre for Polymer and Material Technologies, Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 915, 9052 Zwijnaarde, Belgium; [email protected] (K.R.); [email protected] (L.C.) 2 Laboratory for Chemical Technology, Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 914, 9052 Zwijnaarde, Belgium 3 Centre for Textiles Science and Engineering, Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 907, 9052 Zwijnaarde, Belgium * Correspondence: rudinei.fi[email protected] (R.F.); [email protected] (D.R.D.); Tel.: +32-092-945-830 (R.F.); +32-093-311-772 (D.R.D.) Received: 27 November 2018; Accepted: 20 December 2018; Published: 25 December 2018 Abstract: In the present work, statistical analysis (16 processing conditions and 2 virgin unmodified samples) is performed to study the influence of antioxidants (AOs) during acrylonitrile-butadiene-styrene terpolymer (ABS) melt-blending (220 ◦C) on the degradation of the polybutadiene (PB) rich phase, the oxidation onset temperature (OOT), the oxidation peak temperature (OP), and the yellowing index (YI). Predictive equations are constructed, with a focus on three commercial AOs (two primary: Irganox 1076 and 245; and one secondary: Irgafos 168) and two commercial ABS types (mass- and emulsion-polymerized). Fourier transform infrared spectroscopy (FTIR) results indicate that the nitrile absorption peak at 2237 cm−1 is recommended as reference peak to identify chemical changes in the PB content. -
Fluorescence of Tonic Water Introduction SCIENTIFIC Color Is a Result of the Interaction of Light with Matter
Fluorescence of Tonic Water Introduction SCIENTIFIC Color is a result of the interaction of light with matter. The color that a solution appears to the human eye can change depending on the nature of the light source used to illuminate it. Tonic water appears clear and colorless under normal classroom lights, but is brightly colored when exposed to an ultraviolet (black) light. Concepts • Fluorescence • Absorbance • Transmittance • Emission Materials Tonic water, 500 mL Visible light source—classroom lights work well Beaker, 600-mL Ultraviolet light source—black light Safety Precautions Do not look directly at the black light; its high-energy output can be damaging to eyes. Any food-grade item brought into the lab is con- sidered a laboratory chemical and may not be removed from the lab and later consumed. Wash hands thoroughly with soap and water before leaving the laboratory. Please review current Material Safety Data Sheets for additional safety, handling, and disposal informa- tion. Procedure 1. Pour approximately 500 mL of tonic water into the 600-mL beaker. Observe that the tonic water is clear and colorless. 2. Turn off all the lights and completely darken the room. Turn on the black light and shine it on the tonic water. Observe that the tonic water now appears fluorescent blue in color! Disposal Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. Tonic water may be rinsed down -
Use of Near-Infrared Spectroscopy to Determine the Composition of High-Density/Low-Density Polyethylene Blend Films
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Haverford College: Haverford Scholarship Haverford College Haverford Scholarship Faculty Publications Chemistry 1993 Use of Near-Infrared Spectroscopy to Determine the Composition of High-Density/Low-Density Polyethylene Blend Films Charles E. Miller Haverford College Follow this and additional works at: https://scholarship.haverford.edu/chemistry_facpubs Repository Citation Miller, Charles E. "Use of near-infrared spectroscopy to determine the composition of high-density/low- density polyethylene blend films." Applied spectroscopy 47.2 (1993): 222-228. This Journal Article is brought to you for free and open access by the Chemistry at Haverford Scholarship. It has been accepted for inclusion in Faculty Publications by an authorized administrator of Haverford Scholarship. For more information, please contact [email protected]. Use of Near-Infrared Spectroscopy to Determine the Composition of High-Density/Low-Density Polyethylene Blend Films CHARLES E. MILLER* MATFORSK, Norwegian Food Research Institute, Osloveien 1, N-1430 As Norway The ability of near-infrared (NIR) spectroscopy,combined with principal efficient quality assessment and process control for such component regression (PCR), to nondestructively determine the blend films requires the frequent, and preferably nondestruc- ratio of high-density polyethylene (HDPE) and low-density polyethylene tive, determination of the relative amounts of HDPE and (LDPE) in extruded films is demonstrated. Results indicate that the NIR LDPE. FT-IR reflectance and transmission spectroscopy7 spectrum in the region 2100 to 2500 nm can be used to determine the can be used to perform such thin film analyses. However, HDPE mass percentage of 60-80-~m-thick film samples to within 2.5%, over a range of 0 to 100%.