Physical Sciences and Mathematics Commons^™

Polymer Light Emitting Diodes, Frank E. Karasz, Bin Hu, Zhou Yang

Turkish Journal of Chemistry

Polyphenylene vinylene-based conjugated-nonconjugated alternating block copolymers form the active chromophores in a series of light emitting diodes (LEDs). The quantum efficiency and brightness of these devices can be improved by several orders of magnitude by incorporation of appropriate carrier transport layers and by rational choice of electrodes. Further improvements can be gained by blending of the active chromophores with high or low molecular weight species.

Novel Architectures Of Macromolecular Systems, Gerhard Wegner

Turkish Journal of Chemistry

An important thrust in modern macromolecular chemistry is to construct complex architectures either directly from monomer units, or to design macromolecules capable of forming a desired superstructure by self-organization. Chain-rigidity is an example of a structural principle leading to self organization depending on the aspect ratio of the molecular objects and their mutual interactions. These molecularly defined objects serve as the building blocks of systems for which ultrathin layers composed of hairy rod macromolecules (HRM) are an example. Depending on architectural details layered architectures of HRM are models for molecular nanocomposites, exhibit interesting optical, electrochemical, dielectric or barrier properties. They …

Analytical Applications Of Organic Conducting Polymer Electrodes, Nada F. Atta, George C. Russell, Z. Wang, N. Akmal, J.F. Rubinson, S.K. Lunsford, E. Karagözler, O. Y. Ataman, H. Zimmer, H.B. (Jr.) Mark, Ahmed Galal

Turkish Journal of Chemistry

Electrodes modified by he electrodeposition of conducting polymers were used for the detection and quantitative determination of some inorganic, organic, and biological molecules. Monomers used were five membered ring heterocycles or crown ethers and their derivatives. The polymer films were deposited on glassy carbon or platinum substrates. The resulting electrodes were used in the amperometric mode or in the potentiometric mode for flow injection and chromatographic analyses. The results showed that the proposed modified surface catalyzes the oxidation of organic and biological compounds. The detection of electroinactive inorganic anions, such as F^-, Cl^-, Br^-, NO_2^- and NO^-_3 was also possible …

Reduction Of Combustion Generated Pollution: Process Modifications And Energy Efficient Power Cycles, Janos M. Beer

Turkish Journal of Chemistry

Theoretical bases of combustion process modifications aimed at the reduction of pollutant emission are examined. It is shown, as an example, of how the minimization of emissions of nitrogen oxides leads to a design protocol that translates results of modeling and of bench scale experiments into guidelines for industrial design. The formation and emission of polycyclic aromatic compounds is also considered, because their formation is strongly favored in "low NO_x flames". In power generation the pollutant emission can be reduced effectively by the improvement of the ``heat rate,"i.e., the thermodynamic efficiency of the power cycle. Combined gas turbine-steam cycles which …

Synthesis And Characterization Of Complexes Of Co(Ii), Ni(Ii), Cd(Ii), Hg(Ii) And Pd(Ii) With Some N-Phenyl-N^{1}-2-[4-Phenyl-(Substituted) Thiazolyl]- Thioureas, B. Narayana, M. R. Gajendragad

Turkish Journal of Chemistry

The Synthesis and characterization of the complexes of Co(II), Ni(II), Pd(II), Cd(II) and Hg(II) with N-phenyl-N^{1}-2(-4-phenylthiazoly)thiourea (PPT) and N-phenyl-N^{1}-2-(4-methylphenylthiazolyl)-thiourea (PMPT) and Co(II), Cd(II), and Hg(II) complexes of N-phenyl-N^{1}-2-(4-p- chlorophenylthiazolyl) thiourea (PCPT) are included in this paper. Based on analytical results, electronic and infrared spectral data and magnetic susceptibility measurements, plausible structures have been proposed.

Factors Influencing The Angle Of Total Ii-Electron Energies Of Alternant Hydrocarbons, Lemi Türker

Turkish Journal of Chemistry

Within the framework of the Hückel molecular orbital theory, the topological factors affecting the angle of total \pi-electron energies of alternant hydrocarbons were investigated.

Spectrophotometric Determination Of The Pk_A Values Of Some Aminoacid Complexes Of Pentacyanoferrate(Ii) And Pentacyanoruthenate(Ii), Yakup Baran, Şebnem Baran, N. Kemal Tunali

Turkish Journal of Chemistry

The syntheses, pK_a and spectrospcopic characterization of [Fe(CN)_5(H_2O)]^{-3} and [Ru(CN)_5(H_2O)]^{-3} complexes of alanine(Ala), glycine(Gly), valine(Val), lysine(Lys), arginine(Arg) and cysteine(Cys) complexes were investigated in aqueous solution. The spectra of the complexes containing amino acid ligands were similar to that of [Fe(CN)_5(NH_3)]^{-3}. The pK_a values of the complexes were measured by spectrophotometric titration at 22^{\circ}C and \mu =0.100 M(NaClO_4).

Carbonic Anhydrase From Nicotiana Tabacum Leaves, Nazan Demi̇r, Yaşar Demi̇r

Turkish Journal of Chemistry

In this study, carbonic anhydrase (CA: carbonate hydrolyase; E.C.4.2.1.1) was purified from adult {\it Nicotiana tabacum} leaves and studied biochemically. The enzyme was purified twice times by using (NH$_4)_2SO_4 precipation and DEAE-cellulose column chromatography, and its activity was determined for two different substrates (CO_2 and p-nitrophenyl acetate). The enzyme obtained from the ion exchange column was purified 40.7 fold and the purity was controlled by 3\%-10\% discontinuous SDS-PAGE. The pH of the purified enzyme varied between 6.0 and 7.2, the optimum being 6.9. V_{max} and K_m values were calculated with p-nitrophenyl acetate (0.1524 mM, 0.5446 mM, respectively) as substrate. The …

Determination Of Ponceau 4r And Tartrazine In Various Food Samples By Derivative Spectrophotometric Methods, Sedat Sayar, Yüksel Özdemi̇r

Turkish Journal of Chemistry

Derivative spectrophotometric methods were originally developed for determining Ponceau 4R and Tartrazine in order to resolve their binary mixtures. The method permits the simultaneous determinations of these food colorants in various food samples. Recovery by derivative methods was nearly 100 \%.

Epr Spectroscopy Of Dog-Rose Polyphenoloxidase, Çiğdem Nuhoğlu, Fatih Ucun, Enise Ayyildiz, Y. Kemal Yoğurtçu, Halis Şaki̇roğlu, İrfan Küfrevi̇oğlu

Turkish Journal of Chemistry

Polyphenoloxidase(PPO) of dog-rose fruit was extracted and purified through (NH\4)\2SO\4 precipitation and dialysis. The optimum conditions for this purpose, i.e., pH and temperature, were determined with 4-methylcatechol optimum pH and temperature and found to be pH 8.5 and 20\ci, respectively. The inhibition effect of ascorbic acid was investigated and the I_{50} value was found to be 1.57\times10^{-4} M. The activity of dog-rose PPO was investigated by electron paramagnetic resonance (EPR) at different pH levels and temperatures. The optimum conditions obtained from both spectrophotometry and EPR were compared.

^1h Nmr, Infrared And Mass Spectrometry Of Di- And Tri-Organotin Derivatives Of 1-Nitroso-2-Naphthol, Saqib Ali, Muhammad Mazhar, Moazzam Hussain Bhatti, Sohail Mahmood, Abida Kalsoom

Turkish Journal of Chemistry

The di- and tri-organotin derivatives R\2SnL\2 and R\3SnL where R = CH\3, n--C\4H\9, C\6H\5, C\6H_{11} and C\6H\5CH\2 and L = 1-nitroso-2-naphthoxy were synthesized. These derivatives were characterized by elemental analysis, infrared, ^1H NMR and mass spectrometry.

Some Remarks On Solid State Polymerization, George Adler

Turkish Journal of Chemistry

No abstract provided.

Calculation Of Spreading Pressure Of Water On Cellulosic Films From Contact Angle Data, H. Yıldırım Erbi̇l

Turkish Journal of Chemistry

The correlations between the surface properties of the modified cellulose papers with their toner compatibility were investigated. The surface tension components of the cellulosic films, their interfacial tension with the liquid drops and the work of adhesion components were calculated using van Oss-Good's One-Liquid contact angle approach. The electron donor (or Lewis base) \gamma^- components of the cellulosic films were found to represent the main interactions with the the electron acceptor (acidic) \gamma^+ components of the contacting liquids. Allyl ketene dimer (AKD) grafting of the cellulose affected the surface properties; the higher the substitution of the hydroxyl group, the smaller …

A Quantum-Chemical Investigation On 5,5'-Bi(1h-1.2,4-Triazole)), A. A. İki̇zler, R. Abbasoğlu, N. Saltek, M. Şeri̇fova

Turkish Journal of Chemistry

The conformational analysis of flexible 5,5'-bi(1H-1,2,4-triazole) molecule containing various reaction centers has been performed by the semiempirical methods MNDO,AM1 and PM3, and the internal rotation barrier calculated. The most stable conformation of the molecule has been determined to be the planar trans conformation. According to the three methods, 5,5'-bi(1H-1,2,4-triazole) molecule (C) has been found to be relatively more stable than its tautomer 3,3'-bi(1H-1,2,4-triazole)(B) and to be less stable than its other tautomer 3,3'-bi(4H-1,2,4-triazole)(A). Moreover, the electronic properties of 5,5'-bi(1H-1,2,4-triazole) molecule and the effect of conformational changing on electronic and geometric properties have also been investigated. To determine the protonation sites …

The Reliability Of Jung-Biggs-Moorhead Method For Cholesterol Determination In The Presence Of Ergosterol, Lemi Türker, Şahinde Demi̇rci̇, Marjan Akdağ

Turkish Journal of Chemistry

In the present study, the reliability of Jung-Biggs-Moorhead method for cholesterol determination has been tested in the presence of another steroid, ergosterol. It was observed that presence of ergosterol interferes with the absorbance measurement of cholesterol. When both steroids are present in the sample maximum absorption wavelength are not shifted by the mutual interaction but absorbance values are changed considerably. Therefore this method may be used only for qualitative bu not quantitative analysis for cholesterol in the presence of ergosterol.

Synthesis And Characterisation Of Anhydrous Magnesium Phosphate Mg$_3$(Po$_4$)$_2$, A. Baykal, M. Kizilyalli, R. Kniep

Turkish Journal of Chemistry

The synthesis and characterization of anhydorus Mg_3(PO$_4)_2 was investigated. Mg_3(PO$_4)_2 is reported to have similar structural arrangements with Co_3(PO_4)_2 and \gamma-Zn_3(PO_4)_2 compounds. The sample was prepared by a new technique which is the reaction of MgCl_2.6H_2O and Na_3PO_4.12H_2O solutions at pH=5.1, which was adjusted by adding concentrated H_3PO_4 to the reaction mixture and heating the precipitated product at 600^{\circ}C untill constant weight. The purity of the product was checked by X-ray powder diffraction, IR, density measurement, SEM and DTA analysis. The monoclinic unit cell dimensions of product are a=7.605 (2), b=8.233 (3), c=5.080 (1)A^{\circ} and \beta= 94.19^{\circ} (3), which was …

Hydrolysis And Condensation Reactions Of Methacrylate-Modified Aluminum Alkoxides, Ertuğrul Arpaç, Efraim Avşar

Turkish Journal of Chemistry

The hydrolysis of aluminum tri-sec-butoxide and compounds obtained by substituting the larger functional groups for the present alkly groups in Al(O-sec-Bu)_3, and the reaction of these products with a polymerizable organic ligand, i.e. methacrylic acid, were studied together with the hydrolysis reactions of the final products. A good method of preparing high-tech materials and new composites uses organo-substituted silicon esters and/or alkoxides of various elements in a polycondensation process. Introducing a suitable organic network into the inorganic backbone gives desirable properties in new coating materials. The preparation of such materials is possible via the hydrolysis of metal alkoxides. Usually, different …

Restoring The Waters, Kathryn M. Mutz, Betsy Rieke, University Of Colorado Boulder. Natural Resources Law Center

Books, Reports, and Studies

64 p. : ill. (some col.) ; 28 cm

WATER RIGHTS TRANSFERS FOR INSTREAM FLOWS: Oregon Water Trust / Janet Neuman -- Trust water rights program, Washington / Janet Neuman -- Boulder Creek, Colorado / Carol Ellinghouse, Kathryn Mutz -- Lahontan Valley Wetlands, Nevada / David Yardas -- Conclusion : Challenges for water rights transfers -- PROTECTING AND RESTORING THE WATERS: Umatilla River Basin project, Oregon / Becky Hiers, Jim Cole, Jim Esget, Kathryn Mutz -- Trinity River Basin, California / Michelle Leighton Schwartz, Gregory Thomas -- Ash Meadows, Nevada / David Ledig, Kathryn Mutz -- Colorado River : Grand …

Wiyn Data Distribution And Archiving, Rob Seaman, Ted Von Hippel

Publications

The NOAO/IRAF Save the Bits archive has been operating for over three years at Kitt Peak National Observatory and at the National Solar Observatory's nighttime program. Since that time, the W. M. Keck Observatory and the Cerro Tololo Inter-American Observatory have also adopted the software. These first generation Save the Bits installations rely on Exabyte tapes as the archival medium, typically using pairs of drives to produce duplicate copies of the data for heightened protection against data loss. The upgrade of Save the Bits that is currently in progress to support writable CD-R drives is discussed. In addition to another …

Velocity–Space Drag And Diffusion In A Model, Two-Dimensional Plasma, Mark Anthony Reynolds, B.D. Fried, G.J. Morales

Publications

The quasilinear fluctuation integral is calculated for a two-dimensional, unmagnetized plasma ~composed of charged rods!, and is expressed in terms of Fokker–Planck coefficients. It is found that in two dimensions, the enhanced fluctuations generated by fast electrons lead to anomalously large transport coefficients. In particular, the effect of a small population of fast electrons is only weakly dependent on their density. In three dimensions, the effect of fast electrons is masked by the dominant approximation, but higher-order terms describe processes similar to those in two dimensions, and these terms can become significant for weakly stable plasmas. The differences between two …

Gdr In Superdeformed Nuclei, F. Camera, A. Bracco, A. Atac, R. Bark, I. G. Bearden, J. J. Gaardhoje, B. Herskind, M. Kmiecik, S. Leoni, M. Mattiuzzi, A. Maj, G. Turri

Publications

A search for the gamma decay of the Giant Dipole Resonance built on superdeformed nuclear configurations was made. The superdeformed states of the Eu-143 nucleus were populated using the reaction Pd-110(Cl-37, 4n)Eu-143 at a beam energy of 165 MeV. High energy gamma-rays were detected in 8 large BaF2 scintillators in coincidence with discrete transitions measured with part of the NORDBALL array (17 HPGe detectors and a 2 pi multiplicity filter). Spectra of high-energy gamma-rays gated by low-energy transitions from states fed by the superdeformed bands show an excess yield in the 7-10 MeV region with respect to those gated by …

Hausdorff Dimension Of Boundaries Of Self-Affine Tiles In R N, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

We present a new method to calculate the Hausdorff dimension of a certain class of fractals: boundaries of self-affine tiles. Among the interesting aspects are that even if the affine contraction underlying the iterated function system is not conjugated to a similarity we obtain an upper- and and lower-bound for its Hausdorff dimension. In fact, we obtain the exact value for the dimension if the moduli of the eigenvalues of the underlying affine contraction are all equal (this includes Jordan blocks). The tiles we discuss play an important role in the theory of wavelets. We calculate the dimension for a …

Optical Polarimetry, High–Resolution Spectroscopy And Ir Analysis Of The Chamaeleon I Dark Cloud, E. Covino, E. Palazzi, Bryan E. Penprase, H. E. Schwarz, L. Terranegra

Pomona Faculty Publications and Research

We present optical polarimetry and high resolution spectroscopy of a sample of stars toward the Chamaeleon I dark cloud. We use our polarimetry which includes 33 stars to study the wavelength dependence of the degree and position angle of polarization.

From our data we found, by interpretation of the various correlations between the polarimetry, photometry and IRAS fluxes, the following:
the probable presence of shocked molecular gas; a warm molecular CH component; small dust grains at the edges of the cloud, and larger grains in the central parts, which are causing the polarization.

Our results provide a consistent picture of …

Development Of A High-Speed Ultraviolet Spectrometer, Capable Of Real-Time No And Aromatic Hydrocarbon Detection In Vehicle Exhaust (Presentation), Peter J. Popp, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

The Influence Of Microstructure On The Thermal Degradation Behavior Of Poly(Vinyl Chloride), Hoang Vi Tran

Dissertations, Theses, and Masters Projects

No abstract provided.

Correspondence Between Environmental Gradients And The Assemblage Structure Of Littoral Fishes In The Tidal Portion Of Three Virginia Coastal Plain Rivers, Clifford Michael Wagner

Dissertations, Theses, and Masters Projects

No abstract provided.

Dichlorobis[1-Methyl-3-(Prop-2-Enyl)Imidazole-2(3h)-Thione-S]Zinc(Ii), Daniel J. Williams, Tuan A. Ly, Jeffrey W. Mudge, William T. Pennington, George L. Schimek

Faculty Articles

The title compd. is monoclinic, space group P21/n, with a 14.0082(8), b 10.803(1), c 14.581(1) Å, and β 116.625(8)°; Z = 4, dc = 1.50; R = 0.043,Rw = 0.044 for 1935 reflections. The crystal structure shows a discrete mol. structure with tetrahedral geometry around the Zn ion. The mean Zn-Cl and Zn-S distances are 2.259(7) and 2.372(4) Å, resp. Bond angles around the Zn ion range from 102.8(1) to 113.7(1)°. Ring distances and angles in the ligand compare favorably with literature values of analogous compds., and the mean C-S bond distance of 1.71(1) Å is close to the av. …

Yield-Per-Recruit Analysis And Management Strategies For Atlantic Croaker, Micropogonias Undulatus, In The Middle Atlantic Bight, Luiz R. Barbieri, Mark E. Chittenden, Cynthia M. Jones

OES Faculty Publications

The effect of different fishing mortality (F) and natural mortality (M), and age at first capture (t(c)) on yield-per-recruit of Atlantic croaker, Micropogonias undulatus, in the lower Chesapeake Bay and North Carolina were evaluated with the Beverton-Holt model. Independent of the level of M (0.20-0.35) or F (0.01-2.0) used in simulations, yield-per-recruit values for Chesapeake Bay were consistently higher at t((c)) = 1 and decreased continuously with increases in t(c) (2-5). Although maximum yield-per-recruit always occurred at the maximum level off (F=2.0), marginal increases in yield beyond F = 0.50-0.75 were negligible. Current F (F(CUR)) is estimated to be …

Destruction Of Chloropigments In Copepod Guts, A. B. Bochdansky, D. Deibel

OES Faculty Publications

In a recent account regarding the destruction of chloropigments within the guts of copepods, Head & Harris (1996) (H&H) presented valuable data on pigment destruction in copepods. However, in one of their main conclusions, the authors invoked 2 enzyme pools to explain the pattern of pigment destruction: one directly derived from copepods, the other one produced by the ingested algae. If this conclusion is correct, it would have tremendous impact on the interpretation of data collected by the gut pigment technique. Estimating ingestion rates of copepods in the field would be very difficult, if not impossible, if pigment destruction was …

Detection Of Harmful Algal Blooms Using Photopigments And Absorption Signatures: A Case Study Of The Florida Red Tide Dinoflagellate, Gymnodinium Breve, David F. Millie, Oscar M. Schofield, Gary J. Kirkpatrick, Geir Johnson, Patricia A. Tester, Btyan T. Vintard

OES Faculty Publications

The utility of photopigments and absorption signatures to detect and enumerate the red tide dinoflagellate, Gymnodinium breve, was evaluated in laboratory cultures and in natural assemblages. The carotenoid, gyroxanthindiester, was an adequate biomarker for G. breve biomass; water‐column concentrations corresponded with cell standing crops and chlorophyll a concentrations during bloom events in Sarasota Bay, Florida. Unlike other carotenoids, the relative abundance of gyroxanthin‐diester did not change throughout a range of physiological states in culture and the gyroxanthin‐diester: chlorophyll a ratio exhibited little variability in a natural assemblage during bloom senescence. Stepwise discriminant analysis indicated that wavelengths indicative of in vivo …