Physical Sciences and Mathematics Commons^™

Fire Properties Of Polystyrene-Clay Nanocomposites, Jin Zhu, Alexander B. Morgan, Frank K. Lamelas, Charles A. Wilkie

Chemistry Faculty Research and Publications

Polystyrene−clay nanocomposites have been prepared using a bulk polymerization technique. Three new “onium” salts have been used to prepare the nanocomposites, two are functionalized ammonium salts while the third is a phosphonium salt. By TGA/FTIR, both ammonium and phosphonium treatments have been shown to degrade by a Hofmann elimination mechanism at elevated temperatures. TGA/FTIR showed that the phosphonium treatment is the most thermally stable treatment when compared to the two ammonium salts. The nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, strength and elongation at break, as a measure of the mechanical properties, thermogravimetric analysis, and cone calorimetry. The …

Electron Redistribution Of Aromatic Ligands In (Arene)Cr(Co)3 Complexes. Structural (Bond-Length) Changes As Quantitative Measures, P. Le Maguères, Sergey V. Lindeman, Jay K. Kochi

Chemistry Faculty Research and Publications

Arene ligands experience significant ring expansion upon coordination with chromium tricarbonyl, as established by precise X-ray crystallographic analyses of various (η⁶-arene)Cr(CO)₃ complexes. Such changes in ligand structures result from the charge (electron) redistribution, Ar⁺−Cr^-, upon arene coordination, since they are closely related to those found in the intermolecular 1:1 complexes of the corresponding series of arenes with nitrosonium cation (NO⁺). The latter are prototypical examples of charge-transfer complexes as described by Mulliken. As such, they show enhanced degrees of charge (electron) transfer that approach unity, which is confirmed by quantitative comparison …

Synthesis Of Cyclopropanes Via Organoiron Methodology: Preparation Of 2-(2′-Carboxy-3′-Ethylcyclopropyl)Glycine, Kamil Godula, William Donaldson

Chemistry Faculty Research and Publications

A route to 1,2,3-trisubstituted cyclopropanes has been developed. The relative stereochemistry at the three cyclopropane centers is established by nucleophilic attack on the pentadienyl ligand on the face opposite to iron and subsequent oxidatively induced reductive elimination with retention of configuration. This methodology was applied to the synthesis of 2-(2′-carboxy-3′-ethylcyclopropyl)glycines. The diastereomeric glycine dimethyl esters are separable as their diphenylmethylene imines.

The conformationally restricted glutamate analogs (2S,1′S,2′S,3′R)- and (2R,1′S,2′S,3′R)-ECCG's 5a and5b were prepared in five steps (17 and 15% yield, respectively) from (pentadienyl)Fe(CO) …

Photooxidation Of Polymeric-Inorganic Nanocomposites: Chemical, Thermal Stability And Fire Retardancy Investigations, Adams Tidjani, Charles A. Wilkie

Chemistry Faculty Research and Publications

Nanocomposites of polypropylene-graft-maleic anhydride/clay and polypropylene/clay were prepared by melt blending using two different approaches. X-Ray diffraction results showed an intercalated structure. Samples of nanocomposites were exposed to UV light under atmospheric oxygen and their photo-oxidative stability was studied using FTIR and UV spectroscopy. The consequences of this photo-oxidation on the thermal stability and fire retardant performance of the nanocomposites were also addressed from thermogravimetry analysis and Cone calorimetry.

Xps Characterization Of Friedel-Crafts Cross-Linked Polystyrene, Jiangqi Wang, Jianxin Du, Hongyang Yao, Charles A. Wilkie

Chemistry Faculty Research and Publications

The combination of a difunctional alkylating agent, either hydroxymethylbenzyl chloride or α,α′-dichloroxylene with polystyrene or high-impact polystyrene together with a Friedel-Crafts catalyst, 2-ethylhexyldiphenylphosphate, and an amine to react with hydrogen chloride has been studied by X-ray photoelectron spectroscopy. The results confirm what had been suggested from previous investigations using thermogravimetric analysis; cross-linking of the polymer occurs as the temperature is raised and the alcohol-containing alkylating agent gives a greater amount of cross-linking than does the dichloro compound.

Thermal Degradation Of Pvc In The Presence Of Polystyrene, Qiang Yao, Charles A. Wilkie

Chemistry Faculty Research and Publications

The thermal degradation of poly(vinyl chloride) (PVC) and blends of PVC with polystyrene has been studied using thermogravimetric analysis coupled to Fourier transform infrared spectroscopy. The degradation of PVC commences at weak links by an ionic pathway, but there is evidence to suggest the presence of a radical pathway at high temperatures. While there is some chemical interaction between PVC and polystyrene, the principal mode of stabilization is a physical process.

Automated Alignment By Hybrid Video And 3-D Video Moiré With Both Conventional And Parallel Processing, Barbara Garita, Hector Gutierrez, Ildiko Laszlo, Joel H. Blatt

Aerospace, Physics, and Space Science Faculty Publications

A problem common to automated assembly in manufacturing or in automated docking of spacecraft is angular and lateral alignment of components. A hybrid video system utilizing both conventional imaging and 3-D video moiré has been developed to automatically align a test target with three translational and two rotational degrees of freedom. Alignment was demonstrated via computer controlled translation and rotation stages. The video moiré system is operated in an error map mode, in which a structurally illuminated reference surface is used to chromakey the image of an identical structurally illuminated alignment target. The output is a moiré image generated by …

White Dwarfs In Common Proper Motion Binary Systems: Mass Distribution And Kinematics, Nicole M. Silvestri, Terry D. Oswalt, Matt A. Wood, Jonathan Allyn Smith, Iain Neill Reid, Edward M. Sión

Aerospace, Physics, and Space Science Faculty Publications

We present the mass distribution, gravitational redshifts, radial velocities, and space motions of white dwarf stars in common proper motion binary systems. The mass distribution we derive for the 41 DA white dwarfs in this study has a mean of 0.68 ± 0.04 M⊙. This distribution has a slightly higher mean and larger dispersion than most previous white dwarf studies. We hypothesize that this is due to a higher fraction of cool (average Teff ~ 10,000 K), hence old, white dwarfs in our sample. Our results indicate that samples made up of predominantly cool, old white dwarf stars tend to …

Evidence Of Different Magnetotail Responses To Small Solar Wind Pressure Pulses Depending On Imf Bz Polarity, Mark B. Moldwin, S. S. Mayerberger, Hamid K. Rassoul, Michael R. Collier, Ronald P. Lepping, James A. Slavin, Adam Szabo

Aerospace, Physics, and Space Science Faculty Publications

The response of the magnetotail to small flux rope associated pressure pulses depends on the IMF Bz polarity. Clear and large amplitude magnetotail reverse polarity South-then-North traveling compression regions (SN TCRs) are observed when the pressure pulse is associated with the northward IMF interval of the flux rope. These tail signatures correspond to small-scale (<10 minute duration) pulses of the solar wind dynamic pressure located in front of and within the small-scale flux ropes. Pressure pulses associated with IMF Bz southward are either absent or give rise to smaller amplitude compressions and less systematic lobe Bz rotations. These results suggest that the orientation of the IMF Bz plays a critical role in modulating the magnetotail response to solar wind dynamic pressure pulses.

Nebraska Summary 388: Fendt 918 Vario Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Nebraska Summary 391: Fendt 926 Vario Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Test 1790: 9300 T 24 Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1796: Case Ih Stx 275/New Holland Tj 275 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1797: Case Ih Stx 325/New Holland Tj 325 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Dialectics And The Dao: On Both, A And Non-A In Neutrosophy And Chinese Philosophy, Feng Liu, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

This paper introduces readers to a new approach to dialectical logic: neutrosophy. Specifically it proposes a multi-valued logic in which the statement “both A and Non-A,” historically rejected as logically incoherent, is treated as meaningful. This unity of opposites constitutes both the objective world and the subjective world –a view with deep roots in Buddhism and Daoism, including the I-Ching. This leads in turn to the presentation of a framework for the development of a contradiction oriented learning philosophy inspired by the Later Trigrams of King Wen in the I-Ching. We show that although A and Non-A are logically inconsistent, …

Test 1793: Massey Ferguson 2220 Diesel 12-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Nebraska Summary 389: Fendt 920 Vario Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Nebraska Summary 390: Fendt 924 Vario Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Tractor Test 1780a: White 8785, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Tractor Test 1795: White 8810, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Above‐Threshold Ionization As A Probe Of Multielectron Physics, L. D. Van Woerkom, M. J. Nando, M. A. Walker, G. D. Gillen, H. G. Muller

Physics

The study of above-threshold ionization (ATI) is now over 20 years old and much has been learned about the interaction of a single atomic electron with intense laser fields. The development of stable, high repetition rate ultrashort pulse laser systems has allowed experiments to probe intricate details of the ionization process using photoelectron and photoion spectroscopies. To date the overwhelming majority of data show that intense laser fields interact with only a single electron at a time to produce the well known features in electron kinetic energy spectra. We will present an overview of state-of-the-art experiments in ATI and show …

Intractability And Undecidability In Small Sets Of Wang Tiles, Adam Delisse

Inquiry: The University of Arkansas Undergraduate Research Journal

Imagine a never-ending checkerboard, red and black squares alternating forever in every direction. Now close your eyes, wait for a second, and open them again. There is still the checkerboard, but is it different? Has somebody moved the checkerboard over two squares? Four squares? One million squares? It still looks the same. This is the nature of periodic tilings. Wang tiles are squares, much like the red and black ones used on a checkerboard, except Wang tiles have colors on their edges instead of on the whole square. Also, Wang tiles can only be put edge-to-edge with each other where …

Numerical Ranges Of Composition Operators, Valentin Matache

Mathematics Faculty Publications

Composition operators on the Hilbert Hardy space of the unit disk are considered. The shape of their numerical range is determined in the case when the symbol of the composition operator is a monomial or an inner function fixing 0. Several results on the numerical range of composition operators of arbitrary symbol are obtained. It is proved that 1 is an extreme boundary point if and only if 0 is a fixed point of the symbol. If 0 is not a fixed point of the symbol 1 is shown to be interior to the numerical range. Some composition operators whose …

Iteration Of Λ-Complete Forcing Notions Not Collapsing Λ+, Andrzej Roslanowski

Mathematics Faculty Publications

We look for a parallel to the notion of “proper forcing” among λ-complete forcing notions not collapsing λ+. We suggest such a definition and prove that it is preserved by suitable iterations.

Path Integral Treatment For Spinless Relativistic Equation In The Two Component Theory, M. Merad, T. Boudjedaa, Lyazid Chetouani

Turkish Journal of Physics

In this paper we have set up a path integral formalism for Feshbach-Villars equation by using the fermionic Schwinger model for Pauli matrices which describe an isocharge symmetry. This choice is made in analogy with spin model and the coherent state representation is then used. We have also given a general method of treating the problem of vanishing scalar potential by reducing it the to non-relativistic case and then, via Foldy-Wouthuysen canonical transformation, an explicit solution is constructed. The free case and constant magnetic field interaction are explicitly exposed. In each cases the propagators are evaluated and the energy spectrum …

Vacuum Cryostat's Pressure Dependent Dark Conductivity Measurements On A-Si:H And A-Sin:H Films, İlker Ay, Hüseyi̇n Tolunay

Turkish Journal of Physics

The electrical properties of a-Si:( H ) and a- SiN ):( H ) films prepared by plasma deposition from SiH_4+NH_3 gas mixtures have been investigated. We observed anomalous peaks in the temperature dependent dark conductivity curves of annealed a-Si:H and a-SiN:H samples when the temperatures were increased from 90 K to room temperature at a constant heating rate. To study the surface adsorption effect, vacuum cryostat pressure dependence of these peaks are investigated. We have also studied the effect of nitrogen on these observed peaks in dark conductivity.

A Correlation Of Thin Lens Approximation To Thick Lens Design By Using Coddington Factors In Lens Design And Manufacturing, Ömer Faruk Farsakoğlu, D. Mehmet Zengi̇n, Hi̇kmet Kocabaş

Turkish Journal of Physics

The effect of Coddington factors on aberration functions has been analysed using thin lens approximation. Minimizing spherical aberrations of singlet lenses using Coddington factors in lens design depending on lens manufacturing is discussed. Notation of lens test plate pairs used in lens manufacturing is also presented in terms of Coddington shape factors.

Disk Clearing In The Young Binary Ak Sco, Eric L.N. Jensen

Physics & Astronomy Faculty Works

The pre-main-sequence spectroscopic binary AK Sco is surrounded by a circumbinary disk. Yet while this disk must be somewhat disturbed by the binary at its center, there is no evidence from current data that it has a cleared central hole like those seen in some young binaries, nor that accretion from the outer disk has been cut off. Indeed, most of its spectral and photometric diagnostics are indistinguishable from those of young single stars. Why doesn't this system show any evidence of disturbance of its disk? It may be that the center of the disk is indeed largely cleared, but …

Disks In Young Binary Systems: Unresolved Millimeter-Wave Observations, Eric L.N. Jensen

Physics & Astronomy Faculty Works

Observations at millimeter and submillimeter wavelengths are sensitive to the total mass of circumstellar and circumbinary dust in a multiple system, and in some cases single-dish observations can help constrain the location of disk material in spite of their lack of spatial resolution. Young binary stars show a great diversity of disk properties, with a large part of the variation accounted for by binary separation. Many of the closest binaries (those with separations a less than a few AU) harbor massive circumbinary disks. Binaries with a greater than or equal to 100 AU tend to have massive circumstellar disks. In …

Can Post T Tauri Stars Be Found? Yes!, Eric L.N. Jensen

Physics & Astronomy Faculty Works

I review the observational challenges of finding post T Tauri stars (PTTS), defined here as low-mass, pre-main-sequence stars with ages of 10(7)-10(8) yr. Such stars are difficult to find because they are less active than younger T Tauri stars, and they may not be associated with molecular gas. They are useful for studying the evolution of circumstellar disks and stellar activity between the 10(6)-yr ages of nearby star-forming regions and the main sequence. However, care must be taken in the search process so that the selection criteria used to locate such stars do not bias the sample used for subsequent …