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2006

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Articles 121 - 150 of 592

Full-Text Articles in Chemistry

The Weekend Effect: The Science Suggests That We Are Embarking On An Expensive Policy Which Will Harm The Environment (Presentation), Donald H. Stedman Aug 2006

The Weekend Effect: The Science Suggests That We Are Embarking On An Expensive Policy Which Will Harm The Environment (Presentation), Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

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Scaling And The Smoluchowski Equations, Jerry Goodisman, J. Chaiken Aug 2006

Scaling And The Smoluchowski Equations, Jerry Goodisman, J. Chaiken

Chemistry - All Scholarship

The Smoluchowski equations, which describe coalescence growth, take into account combination reactions between a j-mer and a k-mer to form a (j+k)-mer, but not breakup of larger clusters to smaller ones. All combination reactions are assumed to be second order, with rate constants K jk. The K jk are said to scale if K λj,γk =λ μγ μK jk for j ≤ k. It can then be shown that, for large k, the number density or population of k-mers is given by Ak ae -bk, where A is a normalization constant (a function of a, …

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Application Of Scaling And Kinetic Equations To Helium Cluster Size Distributions: Homogeneous Nucleation Of A Nearly Ideal Gas, J. Chaiken, Jerry Goodisman, Oleg Komilov, J. Peter Toennies Aug 2006

Application Of Scaling And Kinetic Equations To Helium Cluster Size Distributions: Homogeneous Nucleation Of A Nearly Ideal Gas, J. Chaiken, Jerry Goodisman, Oleg Komilov, J. Peter Toennies

Chemistry - All Scholarship

A previously published model of homogeneous nucleation [Villarica et al., J. Chem. Phys. 98, 4610 (1993)] based on the Smoluchowski [Phys. Z. 17, 557 (1916)] equations is used to simulate the experimentally measured size distributions of 4He clusters produced in free jet expansions. The model includes only binary collisions and does not consider evaporative effects, so that binary reactive collisions are rate limiting for formation of all cluster sizes despite the need for stabilization of nascent clusters. The model represents these data very well, accounting in some cases for nearly four orders of magnitude in variation in abundance over …

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Multicentered Integrated Qm:Qm Methods For Weakly Bound Clusters: An Efficient And Accurate 2-Body:Many-Body Treatment Of Hydrogen Bonding And Van Der Waals Interactions, Gregory S. Tschumper Aug 2006

Multicentered Integrated Qm:Qm Methods For Weakly Bound Clusters: An Efficient And Accurate 2-Body:Many-Body Treatment Of Hydrogen Bonding And Van Der Waals Interactions, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

An efficient integrated QM:QM technique for the description of weakly bound clusters is presented. The computational technique described here takes advantage of the recently developed multicentered (MC) integrated QM:QM methods and reliably describes hydrogen bonding and van der Waals interactions by treating all 2-body interactions with a high-level QM method and the many-body interactions with a low-level QM method. Even for small clusters of He, Ne, HF, and water, the MC QM:QM methods are typically 1-3 orders of magnitude faster than the high-level method while introducing an error of less than 1% in the interaction energy. © 2006 Elsevier B.V. …

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Reversed-Phase Hplc Determination Of Citral In Locally Grown Lemon Grass Harvested At Different Season., Mahmoud Al-Shaer Aug 2006

Reversed-Phase Hplc Determination Of Citral In Locally Grown Lemon Grass Harvested At Different Season., Mahmoud Al-Shaer

Electronic Theses and Dissertations

A simple HPLC procedure for the quantitative determination of citral, the major fragrant component in the lemon grass, has been developed. The procedure involves a C-8 stationary phase using a 90:10 methanol: water pH 5 mobile phase containing 0.25% 1-octanesulfonic acid and an UV detector (set at 233 nm). The lemon grass leaves were harvested fresh at different times of the year and were soaked in methanol for 48 hours without any mechanical assistance to extract the citral and other methanol soluble components. The method showed good reproducibility with relative standard deviation of 2.8% and 10.8% for two different sets …

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Polyaniline And Its Derivatives For Environmental Analysis., Atogho Jude Abia Aug 2006

Polyaniline And Its Derivatives For Environmental Analysis., Atogho Jude Abia

Electronic Theses and Dissertations

Electrooxidation has been used to deposit thin film polyaniline as well as its derivative - thin film poly (ortho-phenylenediamine) (POPD) and poly (meta-phenylenediamine) (PMPD) on carbon electrodes, which are subsequently used to monitor the environmental heavy metal ions (Hg2+, Pb2+ ,Cd2+) through a rather unusual "blocking" of anodic stripping for these metals. Using Hg2+ as a model, its cyclic voltammogram for a modified glassy carbon electrode with the resultant polymer shows an enhanced cathodic peak that increases linearly with the analyte ion concentration. POPD also exhibits unique selective detection for organic species. Acetaminophen and …

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Determination Of Cholesterol In Foods By Flow Injection Analysis With Perroxyoxalate Chemiluminescence., Abisake Feleke Aug 2006

Determination Of Cholesterol In Foods By Flow Injection Analysis With Perroxyoxalate Chemiluminescence., Abisake Feleke

Electronic Theses and Dissertations

Cholesterol is an important biological molecule with many important functions. However, high serum cholesterol is a health hazard. Thus analysis of cholesterol is important and many analytical techniques have been developed. The objectives of the proposed research are to develop an economical, rapid method for the determination of total cholesterol with good selectivity and enhanced sensitivity. For evaluation of proposed flow injection analysis with peroxyoxalate chemiluminescence (FIA-POCL) method, figures of merit such as accuracy, precision, and linear dynamic range will be assessed. The proposed procedure was then applied to the determination of total cholesterol in foods. The procedure was linear …

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Tetrakis[2-(2-Pyridyl)Pyridinium] Tetra-Μ3-Iodo-Hexa-Μ2-Iodo-Dodecaiodohexabismuthate And Bis[Tris(2,2'-Bipyridine)Ruthenium(Ii)] Di-Μ4-Iodo-Octa-Μ2-Iodo-Dodecaiodohexabismuthate, Andrea M. Goforth, Meredith A. Tershansy, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye Aug 2006

Tetrakis[2-(2-Pyridyl)Pyridinium] Tetra-Μ3-Iodo-Hexa-Μ2-Iodo-Dodecaiodohexabismuthate And Bis[Tris(2,2'-Bipyridine)Ruthenium(Ii)] Di-Μ4-Iodo-Octa-Μ2-Iodo-Dodecaiodohexabismuthate, Andrea M. Goforth, Meredith A. Tershansy, Mark D. Smith, Leroy Peterson Jr., Hans-Conrad Zur Loye

Faculty Publications

Crystals of the title compounds were grown solvothermally in an ethanol-water solvent mixture using ruthenium triiodide, 2,2'-bipyridine and bismuth triiodide as starting materials. Tetrakis[2-(2-pyridyl)pyridinium] tetra-3-iodo-hexa-2-iodo-dodecaiodohexabismuthate, (C10H9N2)4[Bi6I22], crystallizes in the triclinic space group P and is the major reaction product. The asymmetric unit of this compound consists of half a centrosymmetric [Bi6I22]4- anion and two independent 2,2'-bipyridinium cations. The minor product of the reaction is bis[tris(2,2'-bipyridine)ruthenium(II)] di-4-iodo-octa-2-iodo-dodecaiodohexabismuthate, [Ru(C10H8N2)3] …

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Information Theoretical Approach To Single-Molecule Experimental Design And Interpretation, David Talaga Aug 2006

Information Theoretical Approach To Single-Molecule Experimental Design And Interpretation, David Talaga

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

We use Shannon's definition of information to develop a theory to predict a photon-counting-based single-molecule experiment's ability to measure the desired property. We treat three phenomena that are commonly measured on single molecules: spectral fluctuations of a solvatochromic dye; assignment of the azimuthal dipole angle; determination of a distance by fluorescence resonant energy transfer using Förster's theory. We consider the effect of background and other "imperfections" on the measurement through the decrease in information.

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Europium(Iii) Macrocyclic Complexes With Alcohol Pendant Groups As Chemical Exchange Saturation Transfer Agents, Mark Woods, Donald E. Woessner, Piyu Zhao, Azhar Pasha, Meng-Yin Yang, Ching-Hui Huang, Olga Vasalatiy, Janet R. Morrow, A. Dean Sherry Aug 2006

Europium(Iii) Macrocyclic Complexes With Alcohol Pendant Groups As Chemical Exchange Saturation Transfer Agents, Mark Woods, Donald E. Woessner, Piyu Zhao, Azhar Pasha, Meng-Yin Yang, Ching-Hui Huang, Olga Vasalatiy, Janet R. Morrow, A. Dean Sherry

Chemistry Faculty Publications and Presentations

Paramagnetic lanthanide(III) complexes that contain hyperfine-shifted exchangeable protons offer considerable advantages over diamagnetic molecules as chemical exchange saturation transfer (CEST) agents for MRI. As part of a program to investigate avenues to improve the sensitivity of such agents, the CEST characteristics of europium(III) macrocyclic complexes having appended hydroxyethyl groups were investigated. The CEST spectrum of the asymmetrical complex, EuCNPHC3+, shows five distinct peaks for each magnetically nonequivalent exchangeable proton in the molecule. The CEST spectra of this complex were fitted to NMR Bloch theory to yield exchange rates between each of six exchanging proton pools (five on the …

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Ferritin: Mechanistic Studies And Electron Transfer Properties, Bo Zhang Aug 2006

Ferritin: Mechanistic Studies And Electron Transfer Properties, Bo Zhang

Theses and Dissertations

Ferritins are ubiquitous iron storage proteins in living systems. Although much is known about the iron deposition process in ferritin and a mechanism has been developed, several important issues still remain unknown. One lingering question is the less than stoichiometric quantities of hydrogen peroxide detected in previous studies on animal ferritins. Extensive experimental data on identifying the species in competition for peroxide equivalents point to a surprising conclusion that H2O2 generated in the ferroxidase reaction is consumed by amine buffers that are commonly employed in in vitro ferritin studies, while non-nitrogen containing buffers, such as acetate, phosphate, and carbonate, do …

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Crystal And Molecular Structure Of Bis(8-Phenylmenthyl) 2-(2-Methyl-5-Oxo-3-Cyclohexen-1-Yl)Propandioate, C42H54O5• Ch3Cn, Dennis W. Bennett, Tasneem A. Siddiquee, Daniel T. Haworth, Subhabrata Chaudhury, William A. Donaldson Aug 2006

Crystal And Molecular Structure Of Bis(8-Phenylmenthyl) 2-(2-Methyl-5-Oxo-3-Cyclohexen-1-Yl)Propandioate, C42H54O5• Ch3Cn, Dennis W. Bennett, Tasneem A. Siddiquee, Daniel T. Haworth, Subhabrata Chaudhury, William A. Donaldson

Chemistry Faculty Research and Publications

The X-ray crystal structure of the title compound, as crystallized from acetonitrile-water was determined. The relative stereochemistry of the cyclohexenone ring with respect to the 8-phenylmenthyl esters was determined. The title compound crystallizes in the noncentrosymmetric space group P21, with a=8.9850(10) Å, b=15.575(3) Å, c=14.478(2) Å, β=94.61(2)°, and D calc=1.118 g cm−3 for Z=2.

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The Harmonic Oscillator, The Hermite Polynomial Solutions, Carl W. David Aug 2006

The Harmonic Oscillator, The Hermite Polynomial Solutions, Carl W. David

Chemistry Education Materials

The Hermite polynomial solution to the simple harmonic oscillator is discussed.

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The Harmonic Oscillator, The Ladder Operator Solutions, Carl W. David Aug 2006

The Harmonic Oscillator, The Ladder Operator Solutions, Carl W. David

Chemistry Education Materials

The ladder operator approach to the quantum mechanics of the simple harmonic oscillator is presented.

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Strychninium (S)-2-(2-Bromo­Phen­Oxy)Propanoate 1.4-Hydrate, Kraig A. Wheeler, Aaron M. Lineberry Aug 2006

Strychninium (S)-2-(2-Bromo­Phen­Oxy)Propanoate 1.4-Hydrate, Kraig A. Wheeler, Aaron M. Lineberry

Faculty Research and Creative Activity

In the title mol­ecular salt, C21H23N2O2+·C9H8BrO3−·1.4H2O, the components are linked by inter­molecular C—O−⋯H—+N and OW—H⋯O inter­actions.

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Pseudostationary Phase For Solid Phase Extraction, Qing Zhao Aug 2006

Pseudostationary Phase For Solid Phase Extraction, Qing Zhao

Masters Theses & Specialist Projects

A unique pseudostationary phase for Solid Phase Extraction is presented. This pseudostationary phase consists of surfactant, which is initially immobilized onto hydrophilic cation exchange resin. The surfactant chain through hydrophobic interactions extracts hydrophobic analytes in the same manner as conventional bonded alkyl moieties on silica based non-polar sorbents. Although hydrophobic analytes can be efficiently trapped on commercially available non-polar sorbents (i.e. Ci8 silica), organic solvents that are necessary to break strong hydrophobic interactions between the analytes and the sorbent are harmful. They are also incompatible for direct introduction into a reversed phase liquid chromatographic set up. In the presented approach, …

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Synthesis Of Lanthanum-Strontium Manganites By Oxalate-Precursor Co-Precipitation Methods In Solution And In Reverse Micellar Microemulsion, Vuk Uskoković, Miha Drofenik Aug 2006

Synthesis Of Lanthanum-Strontium Manganites By Oxalate-Precursor Co-Precipitation Methods In Solution And In Reverse Micellar Microemulsion, Vuk Uskoković, Miha Drofenik

Pharmacy Faculty Articles and Research

Nanostructured lanthanum–strontium manganites were synthesized using two different co-precipitation approaches, one in bulk solution, and the other in reverse micelles of CTAB/1-hexanol/water microemulsion. In both cases, precursor cations were precipitated by using oxalic acid. The properties of the materials synthesized by using these two methods were compared in order to reveal potential advantages of the microemulsion-assisted approach. The influence of the annealing conditions on the properties of synthesized manganites was investigated by using X-ray diffraction, transmission electron microscopy, differential thermal analysis, thermogravimetric analysis and magnetic measurements.

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The Impact Of Acid Mine Drainage On West Little Sugar Creek, Vigo Co., In, Jodie L. Gibson Aug 2006

The Impact Of Acid Mine Drainage On West Little Sugar Creek, Vigo Co., In, Jodie L. Gibson

All-Inclusive List of Electronic Theses and Dissertations

This study evaluates the degree and extent of contamination in West Little Sugar Creek by analyzing water chemistry in the stream during low and moderate flow conditions. West Little Sugar Creek is located in Vigo County, Indiana and has been severely impacted by AMD discharging from the abandoned Green Valley Mine site. Stream water is commonly acidic (as low as pH 2.4) with elevated concentrations of Fe and Al and elevated trace elements including Ni, Zn, Cu, Cd, Cr, Co, and others, many of which exceed local and/or national surface water quality standards. Amorphous Fe and Al precipitates also form …

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Investigation Of The Suitability Of The Biscatecholborate Anion As A Reductive Quencher For Photoexcited Ruthenium Polyphyridyl Complexes, Alper Yarasik Aug 2006

Investigation Of The Suitability Of The Biscatecholborate Anion As A Reductive Quencher For Photoexcited Ruthenium Polyphyridyl Complexes, Alper Yarasik

Chemistry & Biochemistry Theses - Archive

Ruthenium polypyridyl complexes [Ru(L-L)3]2+, (L-L = 1,10 - phenanthroline or 2,2'- bipyridine) which covalently linked to electron donor or acceptor units are frequently used in artificial photosystems because of their high emission quantum yields, long excited-state lifetimes, favorable redox properties and excellent chemical stability. The ruthenium dimer P, [(phen)2Ru(tatpp)Ru(phen)2][PF6]4, undergoes multiple photoreductions in the presence of donors such as triethylamine (TEA); however, large amount of donors (0.3 M) are required for efficient reductions. This explores the use of a anionic donor such as [B(cat)2]- with the hypothesis that ion-pairing will result in lower required concentration of the donor. Electrochemical data …

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Hybrid Atomistic-Coarse-Grained Treatment Of Multiscale Processes In Heterogeneous Materials: A Self-Consistent-Field Approach, Dennis J. Diestler, H. Zhou, Ruqiang Feng, Xiao Cheng Zeng Aug 2006

Hybrid Atomistic-Coarse-Grained Treatment Of Multiscale Processes In Heterogeneous Materials: A Self-Consistent-Field Approach, Dennis J. Diestler, H. Zhou, Ruqiang Feng, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

A treatment of multiscale quasistatic processes that combines an atomistic description of microscopic heterogeneous (“near”) regions of a material with a coarse-grained (quasicontinuum) description of macroscopic homogeneous (“far”) regions is presented. The hybrid description yields a reduced system consisting of the original atoms of the near regions plus pseudoatoms (nodes of the coarse-graining mesh) of the far regions, which interact through an effective many-body potential energy Veff that depends on the thermodynamic state. The approximate nature of Veff gives rise to “ghost forces,” which are reflected in spurious heterogeneities close to interfaces between near and far regions. The …

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Novel Approaches To Photoassisted Deposition Of Semiconductors And Nanocomposite Materials, Sashikala Somasundaram Aug 2006

Novel Approaches To Photoassisted Deposition Of Semiconductors And Nanocomposite Materials, Sashikala Somasundaram

Chemistry & Biochemistry Dissertations - Archive

This dissertation research begins with the use of TiO2-based photocatalysis for the reduction of metal ions with very negative reduction potentials. The indirect photocatalytic reduction of four metal ions: Cd2+, Zn2+, Mn2+, and Tl+ using formate radical anions generated in UV-irradiated aqueous TiO2 suspensions, is described. Using Tl+ as a model metal ion, a simple kinetics scheme was developed for the indirect reduction route, and the predictions from this model were shown to be in excellent agreement with experimental data. Titania-based photocatalysis was then used for the preparation of MSe/TiO2 "coupled" semiconductors. Heterogeneous photocatalysis using photoexcited TiO2 substrates was shown …

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Implications Of Mass Education On Chemistry Higher Education, Christine O'Connor Aug 2006

Implications Of Mass Education On Chemistry Higher Education, Christine O'Connor

Articles

The following paper discusses the implications of government policy for widening access and participation in third level institutes. The increase in ‘non-traditional’ students has been widely recognised on an international scale; however, some issues of inequality still exist. The ‘struggles’ associated with widening participation and the creation of a ‘new’ student type are discussed, with particular reference to chemistry education. A change is needed with regard to the pedagogical approach taken by staff in order to cater for a diverse student body comprising a broad range of learner types, and this must be supported both at departmental and institutional levels. …

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Water Solubility Characteristics Of Hydrophobically Modified Polyethyleneimines, Jennifer N. Williams Aug 2006

Water Solubility Characteristics Of Hydrophobically Modified Polyethyleneimines, Jennifer N. Williams

Browse all Theses and Dissertations

Commercially available polyethyleneimines varying in molecular weights and viscosities were synthetically modified in order to increase their hydrophobicity when dissolved in water. Used as additives for inkjet industry inks, these polymers have been designed to promote interaction between formulated inks and paper, while increasing the water-fastness of these water-soluble inks once they are dried on bond paper. Waterfastness, the ability of an ink to maintain print integrity once it becomes wet, as well as optical density, solubility, pH, molecular weight, polydispersity and viscosity are amongst the characteristics analyzed. The modifications of these polyethyleneimines (PEis) with alkyl bromides and alkyl epoxides …

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Nanostructured Layered Copper Hydroxy Dodecyl Sulfate: A Potential Fire Retardant For Poly(Vinyl Ester) (Pve), Everson Kandare, Grace Chigwada, Dongyan Wang, Charles A. Wilkie, Jeanne Hossenlopp Aug 2006

Nanostructured Layered Copper Hydroxy Dodecyl Sulfate: A Potential Fire Retardant For Poly(Vinyl Ester) (Pve), Everson Kandare, Grace Chigwada, Dongyan Wang, Charles A. Wilkie, Jeanne Hossenlopp

Chemistry Faculty Research and Publications

Composites of poly(vinyl ester) (PVE) with copper hydroxy dodecyl sulfate (CHDS) were prepared by thermal curing. The efficiency of the additive, CHDS, in reducing flammability is demonstrated via cone calorimetry and thermogravimetric analysis (TGA). The addition of 1-10% by mass of the CHDS additive resulted in significant increments in char formation (~4-11%) from thermogravimetric analysis (TGA). Incorporation of the CHDS into the polymer matrix at these low concentrations leads to substantial reductions in the total heat release (~20-30%) but no significant change in the peak heat release rate. The composite materials generally ignite more quickly, however, the flame extinguishes faster …

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4,4′-(1,1,1,3,3,3-Hexafluoro­Propane-2,2-Diyl)Bis­(Benzoyl Chloride), Cecilia Rodriguez De Barbarin, Sylvain Bernes, Javier Macossay-Torres, Patrick E. Cassidy Aug 2006

4,4′-(1,1,1,3,3,3-Hexafluoro­Propane-2,2-Diyl)Bis­(Benzoyl Chloride), Cecilia Rodriguez De Barbarin, Sylvain Bernes, Javier Macossay-Torres, Patrick E. Cassidy

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

In the structure of the title mol­ecule, C17H8Cl2F6O2, the dihedral angle between the least-squares planes of the benzene rings is 66.31 (15)°. The CF3 groups adopt an eclipsed conformation.

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Microwave Reflectometry As A Novel Diagnostic Tool For Detection Of Skin Cancers, Pratik Mehta, Kundan Chand, Deepak Narayanswamy, Daryl G. Beetner, R. Zoughi, William V. Stoecker Aug 2006

Microwave Reflectometry As A Novel Diagnostic Tool For Detection Of Skin Cancers, Pratik Mehta, Kundan Chand, Deepak Narayanswamy, Daryl G. Beetner, R. Zoughi, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

More than 1 000 000 people are diagnosed with skin cancer each year in the United States, and more than 10 000 people die from the disease. Methods such as visual inspection and dermoscopy are available for early detection of skin cancers, but improvement in accuracy is needed. This paper investigates the use of microwave reflectometry as a potential diagnostic tool for detection of skin cancers. Open-ended coaxial probes were used to measure microwave properties of skin. The influences of measurement parameters such as probe application pressure, power level, and variation in reflection properties of skin with location and hydration …

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Stable Isotope Compositions Of Organic Carbon And Contents Of Organic Carbon And Nitrogen Of Lacustrine Sediments From Sub-Arid Northern Tanzania, Ann Muzuka Jul 2006

Stable Isotope Compositions Of Organic Carbon And Contents Of Organic Carbon And Nitrogen Of Lacustrine Sediments From Sub-Arid Northern Tanzania, Ann Muzuka

Tanzania Journal of Science

The stable isotope compositions of organic carbon (OC), and contents of OC and nitrogen for four sediment cores recovered from lakes Makat (located in the Ngorongoro Crater), Ndutu and Masek (located in the Serengeti Plains) are used to document sources of organic matter (OM) and climatic changes in sub-arid northern Tanzania during the late Pleistocene-Holocene period. Accelerate mass spectrometer (AMS) 14C ages on total OM for sediments collected from the Ngorongoro Crater Lake indicate that the sedimentation rate is approximately 17 cm/ka. The δC values from the 20 cm long core (short core) show a downcore increase, whereas that of …

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Physico-Chemical And Grain Cooking Characteristics Of Selected Rice Cultivars Grown In Morogoro, N.B. Shayo, P. Mamiro, C. N. M. Nyaruhucha, T. Mamboleo Jul 2006

Physico-Chemical And Grain Cooking Characteristics Of Selected Rice Cultivars Grown In Morogoro, N.B. Shayo, P. Mamiro, C. N. M. Nyaruhucha, T. Mamboleo

Tanzania Journal of Science

A study was carried out at Sokoine University of Agriculture to characterize the local rice varieties grown in Morogoro Region basing on their physical-chemical characteristics and cooking quality parameters. Five cultivars of rice were analyzed and these included Kaling'anaula, Kihogo Red, Salama M17, Supa and Salama. The samples were collected from Crop museum, SUA. The chemical analysis was done to determine the proximate composition, gelatinization temperature and gel consistency as main determinants of cooking quality, sensory evaluation tests was done as determinants for consumer acceptance. The proximate composition results indicated protein content values between 7.94 and 9.46%, ash content between …

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The Lability Of Organic Groups In The Reaction Of 2-(2-Pyridyl)Phenyl(P-Ethoxyphenyl)Tellurium(Ii) With Palladium (Ii) And Platinum (Ii) Chlorides, S. A. Mbogo Jul 2006

The Lability Of Organic Groups In The Reaction Of 2-(2-Pyridyl)Phenyl(P-Ethoxyphenyl)Tellurium(Ii) With Palladium (Ii) And Platinum (Ii) Chlorides, S. A. Mbogo

Tanzania Journal of Science

Reaction between 2- (- pyridyl )phenyl(p-ethoxyphenyl)tellurium(II), RR'Te, and PdCl2 or PtCl2 are complex. The organic groups R and R' are labile, trans-metallation to form RM-groups (M=Pd, Pt) occurs. The solid phases isolated have well defined stoichiometries, eg R'TePdCl, R2R'TePtCl5 and these are discussed together with IR, 1H and 195Pt NMR data.

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The Origin Of Late Archaean Granitoids In The Sukumaland Greenstone Belt Of Northern Tanzania: Geochemical And Isotopic Constraints, M. A. H. Maboko, S. Manya Manya, M. Mwache Mwache, R. B. Pedersen, P. Torssander Jul 2006

The Origin Of Late Archaean Granitoids In The Sukumaland Greenstone Belt Of Northern Tanzania: Geochemical And Isotopic Constraints, M. A. H. Maboko, S. Manya Manya, M. Mwache Mwache, R. B. Pedersen, P. Torssander

Tanzania Journal of Science

Granitoids intruding the late Archaean sequences of the Sukumaland Greenstone Belt of northern Tanzania belong to two distinct geochemical suites. Suite 1 is characterised by Na2O/K2O > 1 (1.04 – 4.67), high Sr/Y (56 – 204) and Ba/Rb ratios (6.1 – 27.1) and low Rb/Sr ratios (0.08 - 0.25). The rocks are enriched in Sr (405 – 1264 ppm) and depleted in Yb (0.17 – 0.93 ppm) and Rb (56 – 132 ppm). On chondrite-normalised REE diagrams, the rocks display highly fractionated patterns characterised by relative LREE enrichment ((La/Yb)N = 23 – 128 and (Gd/Yb)N = 3.10 – 8.54) and lower …

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