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2013

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Articles 9931 - 9960 of 11462

Full-Text Articles in Physical Sciences and Mathematics

Mechanochemical Modification Method Used In The Development Of New Composite Materials Based On Epoxy Binder And Natural Minerals, Umida Ziyamukhamedova, Dilshod Djumabaev, Botirali Shaymardanov Jan 2013

Mechanochemical Modification Method Used In The Development Of New Composite Materials Based On Epoxy Binder And Natural Minerals, Umida Ziyamukhamedova, Dilshod Djumabaev, Botirali Shaymardanov

Turkish Journal of Chemistry

This article highlights the results of a mechanochemical modification method of epoxy composite materials and coatings on their base. It proves the mechanochemical activated components of composition to be the most acceptable for structuring when producing composite materials. It also states the increase of mechanical properties of epoxy heterocomposite coatings with mechanically activated particles by 25%-40%.

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Disposable Carbon Electrodes As An Alternative For The Direct Voltammetric Determination Of Alkyl Phenols From Water Samples, Iulia Gabriela David, Irinel Adriana Badea, Gabriel Lucian Radu Jan 2013

Disposable Carbon Electrodes As An Alternative For The Direct Voltammetric Determination Of Alkyl Phenols From Water Samples, Iulia Gabriela David, Irinel Adriana Badea, Gabriel Lucian Radu

Turkish Journal of Chemistry

Disposable sensors based on a pencil graphite electrode were described for detection of alkyl phenols. The performances of the disposable bare pencil graphite electrode (PGE) and PGE modified with carbon nanotubes, regarding the cyclic and differential pulse voltammetric determination of 4-nonylphenol, 4-octylphenol, and 4-tert-octylphenol, were compared. Some experimental variables of the electrode surface pretreatment and measurement parameters were optimized. Using a phosphate buffer solution (pH 7.40) as the supporting electrolyte, alkyl phenols gave a well-defined oxidation peak at about 700 mV vs. Ag/AgCl. The detection limits established for each alkyl phenol were: 0.25 \muM for 4-octylphenol, 0.42 \muM for 4-nonylphenol, …

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Synthesis, Characterization, And Swelling Behaviors Of A Ph-Responsive Cmc-G-Poly(Aa-Co-Amps) Superabsorbent Hydrogel, Yizhe Wang, Xiaoning Shi, Wenbo Wang, Aiqin Wang Jan 2013

Synthesis, Characterization, And Swelling Behaviors Of A Ph-Responsive Cmc-G-Poly(Aa-Co-Amps) Superabsorbent Hydrogel, Yizhe Wang, Xiaoning Shi, Wenbo Wang, Aiqin Wang

Turkish Journal of Chemistry

New superabsorbent hydrogels were synthesized through free radical graft copolymerization of partially neutralized acrylic acid (AA) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) onto carboxymethyl cellulose (CMC) backbones. The structure and morphology of the synthesized superabsorbent hydrogels were characterized by Fourier transform infrared spectroscopy and scanning electron microscope. The effect of the molar ratio of AMPS to AA, the APS concentration, and the CMC content on swelling ratio was optimized. The swelling properties in various pH solutions and saline solutions as well as the swelling kinetics were also evaluated. Results showed that the introduction of AMPS enhanced the swelling capacity, swelling rate, and …

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Synthesis, Characterization, And Antimicrobial Activity Of Some New Phosphorus Macrocyclic Compounds Containing Pyrazole Rings, Tarik El-Sayed Ali, Salah Abdel-Aziz Abdel-Ghaffar, Kamilia Mohamed El-Mahdy, Somaia Mohamed Abdel-Karim Jan 2013

Synthesis, Characterization, And Antimicrobial Activity Of Some New Phosphorus Macrocyclic Compounds Containing Pyrazole Rings, Tarik El-Sayed Ali, Salah Abdel-Aziz Abdel-Ghaffar, Kamilia Mohamed El-Mahdy, Somaia Mohamed Abdel-Karim

Turkish Journal of Chemistry

A simple synthetic method is reported for the preparation of some new phosphorus macrocycles in which the pyrazole rings are appended to a phosphorus atom. The methodology is based on the cyclocondensation reaction of bis(4-formylpyrazolyl) phosphine oxide(1a, 1b) with nitrogen nucleophiles that contain active terminal amino groups. The antimicrobial activities of the synthesized compounds were assayed.

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Ionic Liquid Mediated Synthesis, Reactions, And Insecticidal Activity Of 1-[(1h-Benzoimidazol-2-Yl)Amino]Spiro[Azetidine-4,4'-[4'H]Chroman]-2-Ones, Dr Kanti Sharma, Renuka Jain Jan 2013

Ionic Liquid Mediated Synthesis, Reactions, And Insecticidal Activity Of 1-[(1h-Benzoimidazol-2-Yl)Amino]Spiro[Azetidine-4,4'-[4'H]Chroman]-2-Ones, Dr Kanti Sharma, Renuka Jain

Turkish Journal of Chemistry

Ionic liquid mediated synthesis of novel heterocyclic compounds 1-[(1H-benzoimidazol-2-yl)amino]-2'-phenylspiro[azetidine- 4,4'-[4'H]chroman]-2-ones (3) and 1-[(1H-benzoimidazol-2-yl)amino]- 3-chloro-2'-phenylspiro[aze tidine-4,4'-[4'H] chroman]-2-ones (4) was accomplished by condensing substituted 2-hydrazino benzimidazole (1), flavanone (2), and acetyl chloride/chloroacetyl chloride in ionic liquid, [bmim]PF_6 with or without using catalyst in excellent yield (90%--95%). Further, compounds 3 and 4 were acylated with trifluoroacetic anhydride to give N-acylated products (5 and 10); 3 when treated with HCHO and (C_2H_5)_2NH gave Mannich bases (6) and with aldehydes afforded 3-arylidene-2-azetidinone (7). Compounds 4 underwent nucleophilic substitution with (i) KI (Finkelstein reaction) and (ii) phenols to give the corresponding iodo and phenoxy derivatives (8 …

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Synthesis And Evaluation Of Acetylcholineesterase Inhibitory Potential And Antioxidant Activity Of Benzothiazine Derivatives, Durre Shahwar, Uzma Sana, Naeem Ahmad Jan 2013

Synthesis And Evaluation Of Acetylcholineesterase Inhibitory Potential And Antioxidant Activity Of Benzothiazine Derivatives, Durre Shahwar, Uzma Sana, Naeem Ahmad

Turkish Journal of Chemistry

The aim of the present study was to synthesize and characterize benzothiazine derivatives prepared by using 2-aminothiophenol and saccharine and in vitro screen their enzyme inhibition and antioxidant potential. Nine different derivatives were prepared and their structures were confirmed by spectral studies (EIMS, ^1 H and ^{13}C NMR). Enzyme inhibition potential of the synthesized compounds was evaluated by Ellman's method, while antioxidant activity was determined by DPPH and FRAP assays. All the derivatives showed remarkable activity against acetylcholine esterase with IC_{50} values in the range of 35.9--122.0 \mu M. All other derivatives, except compound 4a, were inactive towards DPPH radical. …

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Synthesis And Antimicrobial Investigation Of Some 5h-Pyridazino[4,5-B]Indoles, İlker Avan, Alaetti̇n Güven, Kiymet Güven Jan 2013

Synthesis And Antimicrobial Investigation Of Some 5h-Pyridazino[4,5-B]Indoles, İlker Avan, Alaetti̇n Güven, Kiymet Güven

Turkish Journal of Chemistry

Synthesis and in vitro antimicrobial activities are reported for a series of 1,3,5-substituted 4-oxo-3,4-dihydro-5H-pyridazino[4,5-b]indole derivatives. Corresponding pyridazino[4,5-b]indoles were prepared from ethyl 3-formyl-1H-indole-2-carboxylate precursors and the functional group in question was installed with hydrazine and its derivatives. The purity and primary structures of pyridazino[4,5-b]indole were confirmed by IR, ^1 H NMR, and ^{13}C NMR spectroscopy and elemental analyses. All of the indoles were tested for in vitro antimicrobial activity against 8 isolates of bacteria and a fungus including Staphylococcus aureus NRRL B-767, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Proteus vulgaris NRRL-B123, Salmonella typhimurium NRRL B-4420, Bacillus subtilis NRRL 744, …

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Application Of Experimental Design On Determination Of Aluminum Content In Saline Samples By Adsorptive Cathodic Stripping Voltammetry, Si̇nan Yilmaz, Betül Öztürk, Durmuş Özdemi̇r, Ahmet Emi̇n Eroğlu, Fatma Ni̇l Ertaş Jan 2013

Application Of Experimental Design On Determination Of Aluminum Content In Saline Samples By Adsorptive Cathodic Stripping Voltammetry, Si̇nan Yilmaz, Betül Öztürk, Durmuş Özdemi̇r, Ahmet Emi̇n Eroğlu, Fatma Ni̇l Ertaş

Turkish Journal of Chemistry

Adsorptive cathodic stripping voltammetric determination of aluminum at ng mL^{-1} levels in salt samples based on the metal complexation with Calcon (1-(2-hydroxynaphthylazo)-2 naphthol-4-sulfonic acid) and the subsequent adsorptive deposition onto a hanging mercury drop electrode was studied. Central composite design was used as a design method. Several chemical and instrumental parameters (pH, ligand concentration, deposition time, deposition potential, and complexing time) were involved in the experimental design. Analytical parameters such as repeatability, linearity, and accuracy were also investigated and the detection limit was found as 0.32 ng mL^{-1}.

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Theoretical Study On The Addition Reaction Between Propadienylidene And Methyleneimine, Mengyuan Wang, Yungang Chen, Shanshan Ding, Yingde Wang, Qianchao Cao, Xiaojun Tan, Jinsong Gu Jan 2013

Theoretical Study On The Addition Reaction Between Propadienylidene And Methyleneimine, Mengyuan Wang, Yungang Chen, Shanshan Ding, Yingde Wang, Qianchao Cao, Xiaojun Tan, Jinsong Gu

Turkish Journal of Chemistry

The reaction mechanism between propadienylidene and methyleneimine was systematically investigated employing the second-order Møller--Plesset perturbation theory (MP2) method with the 6 -- 31 + G* basis set. Geometry optimization, vibrational analysis, and energy property of the involved stationary points on the potential energy surface were calculated. The energies of the different species were corrected by single point energy calculations at the CCSD (T) // MP2 / 6 -- 31 + G* level. From the surface energy profile, one important initial intermediate characterized by a 3-membered ring structure was located via a transition state firstly. After that, 3 different products possessing …

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Terpenoids, Essential Oil Composition, Fatty Acid Profile, And Biological Activities Of Anatolian Salvia Fruticosa Mill., Gülaçti Topçu, Mehmet Öztürk, Tuba Kuşman, Ayşe Asli Barla Demi̇rkoz, Ufuk Kolak, Ayhan Ulubelen Jan 2013

Terpenoids, Essential Oil Composition, Fatty Acid Profile, And Biological Activities Of Anatolian Salvia Fruticosa Mill., Gülaçti Topçu, Mehmet Öztürk, Tuba Kuşman, Ayşe Asli Barla Demi̇rkoz, Ufuk Kolak, Ayhan Ulubelen

Turkish Journal of Chemistry

The hexane and dichloromethane extracts, obtained by re-extraction of the methanol extract of Salvia fruticosa Mill., afforded 7 diterpenoids (carnosol, carnosic acid, carnosic acid 12-methyl ether, rosmadial, isorosmanol, ferruginol, and manool), 4 triterpenoids (\alpha -amyryltetracosanoate, oleanolic acid, ursolic acid, and erythrodiol), a steroid (3-acetylsitosterol), and a flavone (salvigenin). The galls (apples) of the collected plant were separately extracted with hexane to afford fatty acids composed mainly of oleic acid (29\%), palmitoleic acid (29\%), and stearic acid (23.20\%), which exhibited high anticholinesterase activity, particularly against BChE. The essential oil, obtained from the aerial parts of the plant, exhibited high AChE inhibitory …

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Poly(4-Vinylpyridine)-Supported Dual Acidic Ionic Liquid: An Environmentally Friendly Heterogeneous Catalyst For The One-Pot Synthesis Of 4,4'-(Arylmethylene)Bis(3-Methyl-1-Phenyl-1h-Pyrazol-5-Ols), Kaveh Parvanak Boroujeni, Pegah Shojaei Jan 2013

Poly(4-Vinylpyridine)-Supported Dual Acidic Ionic Liquid: An Environmentally Friendly Heterogeneous Catalyst For The One-Pot Synthesis Of 4,4'-(Arylmethylene)Bis(3-Methyl-1-Phenyl-1h-Pyrazol-5-Ols), Kaveh Parvanak Boroujeni, Pegah Shojaei

Turkish Journal of Chemistry

A poly(4-vinylpyridine)-supported Brønsted ionic liquid was easily prepared from its starting materials and used as a novel, highly efficient, and reusable heterogeneous catalytic system for the synthesis of 4,4'-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ols) from the condensation reaction between aromatic aldehydes and 2 equivalents of 3-methyl-l-phenyl-5-pyrazolone.

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A Kinetic Study Of Atom Transfer Radical Polymerization Of Styrene With Bis(2-Pyridyl)Ethylenedimethanimine Derivative Ligands, Hülya Arslan, Yasemi̇n Küçük, Ayfer Menteş, Meti̇n Hayri̇ Acar Jan 2013

A Kinetic Study Of Atom Transfer Radical Polymerization Of Styrene With Bis(2-Pyridyl)Ethylenedimethanimine Derivative Ligands, Hülya Arslan, Yasemi̇n Küçük, Ayfer Menteş, Meti̇n Hayri̇ Acar

Turkish Journal of Chemistry

Atom transfer radical polymerization (ATRP) of styrene was carried out with multidentate nitrogen-based ligands, namely N,N'-bis[phenyl(pyrid-2-yl)methylene] ethane-1,2-diamine (BPDA) and N,N'-bis[methyl(pyrid-2-yl)methylene] ethane-1,2-diamine (BMDA), and catalyst systems at catalyst/ligand molar ratios of 1/0.33, 1/0.5, 1/1, and 1/1.5 by using 2 different initiators, (1-bromoethyl)benzene (BEB) and ethyl-2-bromopropionate (EBP). Linear first-order kinetic plots were observed for ATRP of styrene upon using BPDA as a ligand with both initiators. Even though the linear slopes indicate that radical concentration remains constant during reactions, high molecular weights were obtained at low conversion and showed a linear relation thereafter. To investigate the molecular weight effect, reactions were also …

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A New Anthracene Derivative Of Calix[4]Arene As A Fluorescent Chemosensor, Özlem Şahi̇n, Mustafa Şahi̇n, Nuri̇ye Koçak, Mustafa Yilmaz Jan 2013

A New Anthracene Derivative Of Calix[4]Arene As A Fluorescent Chemosensor, Özlem Şahi̇n, Mustafa Şahi̇n, Nuri̇ye Koçak, Mustafa Yilmaz

Turkish Journal of Chemistry

A new anthracene derivative of calix[4]arene was synthesized as a highly fluorescent compound. This compound was examined for its fluorescent properties towards different metal ions (Li^+, Na^+, Mg^{2+}, Ca^{2+}, Ba^{2+}, Ni^{2+}, Cu^{2+}, Zn^{2+}, Pb^{2+}) by UV and fluorescence spectroscopy. On complexation by alkaline earth metal cations and transition metal cations, the fluorescence spectrum was quenched. In particular, Ca^{2+} caused greater than 98% quenching of the anthracene derivative of calix[4]arene.

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Synthesis Of 3,4-Diaryl-1-Phenyl-4,5-Dihydro-1h-Pyrazole-5-Carbonitriles Via 1,3-Dipolar Cycloaddition Reactions, Jayaroopa Prabhashankar, Vasanth Kumar Govindappa, Ajay Kumar Kariyappa Jan 2013

Synthesis Of 3,4-Diaryl-1-Phenyl-4,5-Dihydro-1h-Pyrazole-5-Carbonitriles Via 1,3-Dipolar Cycloaddition Reactions, Jayaroopa Prabhashankar, Vasanth Kumar Govindappa, Ajay Kumar Kariyappa

Turkish Journal of Chemistry

Nitrile imines generated by the oxidative dehydrogenation of aromatic aldehyde phenylhydrazones with chloramine-T as a catalytic dehydrogenating agent were trapped in situ by 4-methoxy cinnamonitrile to afford 3,4-diaryl-1-phenyl-4,5-dihydro-1H-pyrazole-5-carbonitrile in moderate to good yields. The structures of the cycloadducts were confirmed by spectral studies and elemental analysis.

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Biodegradability Of Degradable Mulching Film In A Laboratory-Controlled Composting Test, Xuemei Zhang, Yaxi Huang, Deqiang Li, Zicheng Wen, Baoxun Sui, Zhiyong Liu Jan 2013

Biodegradability Of Degradable Mulching Film In A Laboratory-Controlled Composting Test, Xuemei Zhang, Yaxi Huang, Deqiang Li, Zicheng Wen, Baoxun Sui, Zhiyong Liu

Turkish Journal of Chemistry

A series of degradable films was prepared, and 2 formulas of polyethylene (PE) films with the highest degradable performance were experimentally determined. These films contained 3.43% and 0.44% stearate, and were denoted as PE-3 and PE-4, respectively. Their biodegradability was studied in a laboratory-controlled composting test using ordinary PE film (OPEF) as a control. Contrast composting experiments indicated that the biodegradability of untreated samples was very low, and that the biodegradation rates of PE films after natural aging were significantly higher. FT-IR analysis showed that OPEF changed little after the composting experiment, and that PE-3 and PE-4 showed a carbonyl …

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Novel Flame Retardant Poly(Thiourea-Sulfone-Imide)S For High Temperature Applications: Synthesis And Characterization, Ghulam Waris, Humaira Masood Siddiqi, Lance Twyman, Rizwan Hussain, Zareen Akhter, Muhammad Saeed Butt Jan 2013

Novel Flame Retardant Poly(Thiourea-Sulfone-Imide)S For High Temperature Applications: Synthesis And Characterization, Ghulam Waris, Humaira Masood Siddiqi, Lance Twyman, Rizwan Hussain, Zareen Akhter, Muhammad Saeed Butt

Turkish Journal of Chemistry

The synthesis and polymerization of a novel diamine monomer, 1,1-(sulfonylbis (4,1-phenylene)) bis (thiourea) (SPT), with various aromatic dianhydrides were carried out. In addition, the fabrication of poly(thiourea-sulfone-imide)s (PTSIs) with noble thermal properties and flame retardancy was conducted. The structures of SPT and polymers were characterized by FT-IR, ^1H NMR, and ^{13}C NMR spectroscopy along with elemental analysis. Crystallinity, organosolubility, inherent viscosity, and gel permeation chromatographic measurements were taken as well. The amorphous nature was exhibited by PTSIs containing C=S and --SO_2- moieties in the backbone that were readily soluble in highly polar organic solvents. The inherent viscosities of PTSIs were …

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Large-Scale Cooperative Task Distribution On Peer-To-Peer Networks, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins Jan 2013

Large-Scale Cooperative Task Distribution On Peer-To-Peer Networks, Daniel R. Karrels, Gilbert L. Peterson, Barry E. Mullins

Faculty Publications

Large-scale systems are part of a growing trend in distributed computing, and coordinating control of them is an increasing challenge. This paper presents a cooperative agent system that scales to one million or more nodes in which agents form coalitions to complete global task objectives. This approach uses the large-scale Command and Control (C2) capabilities of the Resource Clustered Chord (RC-Chord) Hierarchical Peer-to-Peer (HP2P) design. Tasks are submitted that require access to processing, data, or hardware resources, and a distributed agent search is performed to recruit agents to satisfy the distributed task. This approach differs from others by incorporating design …

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Short Chain Fatty Acid Production By Probiotic Organisms In The Gastrointestinal Tract, Elyssa Rautiola Jan 2013

Short Chain Fatty Acid Production By Probiotic Organisms In The Gastrointestinal Tract, Elyssa Rautiola

Senior Honors Theses and Projects

Interest in determining the mechanism by which pro biotic bacteria in the gastrointestinal tract produce short chain fatty acids (SCFA) has increased over the past few years. This study uses gas chromatography and mass spectrometry to characterize lactate production in aerobic test tube cultures, aerobic bioreactor cultures, and anaerobic bioreactor cultures. To collect anaerobic bioreactor samples, a novel in vitro anaerobic model was developed. The pH and colony forming units of each bacterial sample was also measured in order to understand the correlation between lactate production and bacterial growth. The purpose of this study was to analyze production of SCFA …

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The Tilt Of The Boron Triangle In Tourmaline, Charles J. Badgerow Jan 2013

The Tilt Of The Boron Triangle In Tourmaline, Charles J. Badgerow

Senior Honors Theses and Projects

The tourmaline mineral group has a highly complex chemical composition and provides a wealth of information on Earth's processes. Past research has revealed numerous mysteries regarding the structure of the boron triangle within tourmaline, especially as it bonds to the Z- and Z'- cation sites. Although the Z- and Z' - are nominally the same site, the Z'-site has a greater effect on the stereochemistry of the boron triangle. Further, the Z' -site has a shorter bond-length with the boron triangle than the Z-site. We hypothesize that this variation affects the stereochemistry of the boron triangle, and have analyzed a …

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Synthesis Of 1-Pyrenyldiazomethane For Derivatization Of Short-Chain Fatty Acids, Mary E. Kalvaitis Jan 2013

Synthesis Of 1-Pyrenyldiazomethane For Derivatization Of Short-Chain Fatty Acids, Mary E. Kalvaitis

Senior Honors Theses and Projects

Use of I-pyrenyldiazomethane (PDAM) for derivatizing short-chain fatty acids (SCFA) is a successful way to analyze complex SCF A samples quickly and with minimal sample preparation. The costs associated with ordering PDAM from a commercial source can be high, typically more than $300 not including shipping costs. This project developed a simple two-step synthesis procedure that can be used in undergraduate chemistry laboratories. We found that the PDAM produced by this procedure is pure enough to use for our derivatization needs without further purification. This synthesis can be used to further explore the use of PDAM for fast and simple …

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Active Optimal Control Strategies For Increasing The Efficiency Of Photovoltaic Cells, Sharif Aljoaba Jan 2013

Active Optimal Control Strategies For Increasing The Efficiency Of Photovoltaic Cells, Sharif Aljoaba

Theses and Dissertations--Electrical and Computer Engineering

Energy consumption has increased drastically during the last century. Currently, the worldwide energy consumption is about 17.4 TW and is predicted to reach 25 TW by 2035. Solar energy has emerged as one of the potential renewable energy sources. Since its first physical recognition in 1887 by Adams and Day till nowadays, research in solar energy is continuously developing. This has lead to many achievements and milestones that introduced it as one of the most reliable and sustainable energy sources. Recently, the International Energy Agency declared that solar energy is predicted to be one of the major electricity production energy …

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Ricamar2013: Rilievi Per La Caratterizzazione Dell'ambiente Marino Nel Golfo Di Pozzuoli. Rapporto Sull'attivita 13 - 31 Maggio 2013, C. Carmisciano, M. Grassi, L. Cocchi, Giuseppe Masetti, M. Filippone, E. Ricci, M. Pratellesi, Roberta Ivaldi, Giovanni Iannaccone, Giovanna Berrino, Guiseppe De Natale, Giovanni Chiodini, Sefano Caliro, Lorenzo Dialti, Matteo Guideri, F. Muccini, Paolo Stefanelli, Giovanni Orsi, Valerio Iafolla, Francesco Italiano, Fabrizia Buongiorno, Salvatore Stramondo, Christian Bignami, Marco Polcari, Malvina Silvestri Jan 2013

Ricamar2013: Rilievi Per La Caratterizzazione Dell'ambiente Marino Nel Golfo Di Pozzuoli. Rapporto Sull'attivita 13 - 31 Maggio 2013, C. Carmisciano, M. Grassi, L. Cocchi, Giuseppe Masetti, M. Filippone, E. Ricci, M. Pratellesi, Roberta Ivaldi, Giovanni Iannaccone, Giovanna Berrino, Guiseppe De Natale, Giovanni Chiodini, Sefano Caliro, Lorenzo Dialti, Matteo Guideri, F. Muccini, Paolo Stefanelli, Giovanni Orsi, Valerio Iafolla, Francesco Italiano, Fabrizia Buongiorno, Salvatore Stramondo, Christian Bignami, Marco Polcari, Malvina Silvestri

Center for Coastal and Ocean Mapping

No abstract provided.

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Combining Angular And Spatial Information From Multibeam Backscatter Data For Improved Unsupervised Acoustic Seabed Segmentation, Alexandre C. Schimel, Yuri Rzhanov, Luciano E. Fonseca, M Mayer, Dirk Immenga Jan 2013

Combining Angular And Spatial Information From Multibeam Backscatter Data For Improved Unsupervised Acoustic Seabed Segmentation, Alexandre C. Schimel, Yuri Rzhanov, Luciano E. Fonseca, M Mayer, Dirk Immenga

Center for Coastal and Ocean Mapping

No abstract provided.

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Observations Of The Vertical Structure Of Tidal Currents In Two Inlets, Thomas C. Lippmann, James D. Irish, Jonathan Hunt Jan 2013

Observations Of The Vertical Structure Of Tidal Currents In Two Inlets, Thomas C. Lippmann, James D. Irish, Jonathan Hunt

Center for Coastal and Ocean Mapping

Observations of the vertical structure of broad band tidal currents were obtained at two energetic inlets. Each experiment took place over a 4 week period, the first at Hampton Inlet in southeastern New Hampshire, USA, in the Fall of 2011, and the second at New River Inlet in southern North Carolina, USA, in the spring of 2012. The temporal variation and vertical structure of the currents were observed at each site with 600 kHz and 1200 kHz RDI Acoustic Doppler Current Profilers (ADCP) deployed on low-profile bottom tripods in 7.5 and 12.5 m water depths near the entrance to Hampton …

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Bathymetric Terrain Model Of The Atlantic Margin For Marine Geological Investigations., Brian Andrews, Jason D. Chaytor, Uri S. Ten Brink, Daniel S. Brothers, James V. Gardner Jan 2013

Bathymetric Terrain Model Of The Atlantic Margin For Marine Geological Investigations., Brian Andrews, Jason D. Chaytor, Uri S. Ten Brink, Daniel S. Brothers, James V. Gardner

Center for Coastal and Ocean Mapping

Bathymetric terrain models of seafloor morphology are an important component of marine geological investigations. Advances in acquisition and processing technologies of bathymetric data have facilitated the creation of high-resolution bathymetric surfaces that approach the resolution of similar surfaces available for onshore investigations. These bathymetric terrain models provide a detailed representation of the Earth’s subaqueous surface and, when combined with other geophysical and geological datasets, allow for interpretation of modern and ancient geological processes. The purpose of the bathymetric terrain model presented in this report is to provide a high-quality bathymetric surface of the Atlantic margin of the United States that …

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Polybenzoxazine Aerogels: Synthesis, Characterization, Conversion To Porous Carbons, And Energetic Composites, Shruti Mahadik-Khanolkar Jan 2013

Polybenzoxazine Aerogels: Synthesis, Characterization, Conversion To Porous Carbons, And Energetic Composites, Shruti Mahadik-Khanolkar

Doctoral Dissertations

"Aerogels are nanoporous, low-density bulk objects, consisting of three-dimensional assemblies of nanoparticle. Structured similarly, polymeric aerogels are emerging as a mechanically strong alternative to traditional silica aerogels, which are fragile. Amongst polymeric aerogels, those based on polybenzoxazine (PBO - a type of phenolic resin), are extremely robust and comprise an economic alternative to resorcinol-formaldehyde aerogels, also a class of phenolic resins, as the main source of carbon aerogels. The drawback of the PBO chemistry has been the long (days) processing time at high-temperatures (>130 ºC). Herewith, we have developed an energy- and time-efficient process to PBO aerogels by inducing …

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Isocyanate-Derived Organic Aerogels: Polyurethanes, Polyureas, Polyamides And Polyimides, Chakkaravarthy Chidambareswarapattar Jan 2013

Isocyanate-Derived Organic Aerogels: Polyurethanes, Polyureas, Polyamides And Polyimides, Chakkaravarthy Chidambareswarapattar

Doctoral Dissertations

"Aerogels are 3D assemblies of nanoparticles with high open porosity and high surface area, and are pursued for their low density, low thermal conductivity, low dielectric constant and high acoustic attenuation. The foundation for those exceptional properties is their complex hierarchical solid framework (agglomerates of porous, fractal secondary nanoparticles). On the down side, however, aerogels are also fragile materials. The mechanical strength of silica aerogels has been improved by crosslinking the framework with organic polymers. The crosslinking polymer has been assumed to form a conformal coating on the surface of the skeletal framework bridging covalently the elementary building blocks. However, …

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Polarization And Opinion Analysis In An Online Argumentation System For Collaborative Decision Support, Ravi Santosh Arvapally Jan 2013

Polarization And Opinion Analysis In An Online Argumentation System For Collaborative Decision Support, Ravi Santosh Arvapally

Doctoral Dissertations

"Argumentation is an important process in a collaborative decision making environment. Argumentation from a large number of stakeholders often produces a large argumentation tree. It is challenging to comprehend such an argumentation tree without intelligent analysis tools. Also, limited decision support is provided for its analysis by the existing argumentation systems. In an argumentation process, stakeholders tend to polarize on their opinions, and form polarization groups. Each group is usually led by a group leader. Polarization groups often overlap and a stakeholder is a member of multiple polarization groups. Identifying polarization groups and quantifying a stakeholder's degree of membership in …

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Range Maps For Nebraska's Threatened And Endangered Species, Nebraska Natural Heritage Program Jan 2013

Range Maps For Nebraska's Threatened And Endangered Species, Nebraska Natural Heritage Program

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

This document includes maps and associated information on the ranges of Nebraska’s federal and state-listed species. The information is current as of January 2013. The information is updated as needed. Contact the Nebraska Game and Parks Commission to determine if a more current version is available. The species treated are as follows: American Burying Beetle (Nicrophorus americanus), Salt Creek Tiger Beetle (Cicindela nevadica lincolniana), Swift Fox (Vulpes velox), River Otter (Lutra canadensis), Southern Flying Squirrel (Glaucomys volans), Pallid Sturgeon (Scaphirhyncus albus), Topeka Shiner (Notropis topeka), Sturgeon Chub (Macrhybopsis gelida), Blacknose Shiner (Notropis heterolepis), Lake Sturgeon (Acipenser fulvescens), Northern Redbelly Dace …

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Reducing Communication Delay Variability For A Group Of Robots, Goncalo Martins Jan 2013

Reducing Communication Delay Variability For A Group Of Robots, Goncalo Martins

Electronic Theses and Dissertations

A novel architecture is presented for reducing communication delay variability for a group of robots. This architecture relies on using three components: a microprocessor architecture that allows deterministic real-time tasks; an event-based communication protocol in which nodes transmit in a TDMA fashion, without the need of global clock synchronization techniques; and a novel communication scheme that enables deterministic communications by allowing senders to transmit without regard for the state of the medium or coordination with other senders, and receivers can tease apart messages sent simultaneously with a high probability of success. This approach compared to others, allows simultaneous communications without …

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