Identification of Elastomers in Tire Sections by Total Thermal Analysis. II. White Sidewall Compounds of EPDM and Blends

1975 ◽  
Vol 48 (4) ◽  
pp. 631-639 ◽  
Author(s):  
A. K. Sircar ◽  
T. G. Lamond
Keyword(s):  
Thermal Analysis ◽  
Infrared Analysis ◽  
Endothermic Reaction ◽  
Close Correspondence ◽  
White Side ◽  
Side Walls ◽  
The Difference ◽  
Corroborative Evidence ◽  
The Many ◽  
Good Agreement

Abstract Total thermal analysis curves can identify all polymers in the blends of EPDM and other elastomers that are used for white side walls. DSC and DTG curves in nitrogen are most promising, while those in oxygen can be used as corroborative evidence. There is close correspondence between DSC and DTG peak temperatures for the elastomers that degrade by endothermic reaction (EPDM, CIIR). The difference in glass transition temperature of the many combinations is not big enough, but this also provides corroborative evidence. The method has been tried in analyzing white sidewalls from commercial tires and was found to give results in good agreement with infrared analysis in most cases.

Effects of boundary walls on the properties of settling spheres

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sadia Haider ◽  
Atta Ullah ◽  
Adnan Hamid
Keyword(s):  
Volume Fraction ◽  
Fluid Model ◽  
Solid Volume Fraction ◽  
Stokes Number ◽  
Particle Interactions ◽  
Kinetic Trap ◽  
Side Walls ◽  
Two Fluid Model ◽  
The Many ◽  
Good Agreement

Abstract Numerical Simulations are performed, using Eulerian two fluid model (TFM) to investigate the effects of solid volume fraction and no-slip side walls on the settling particles. It is found that average settling velocity decreases with increasing volume fraction for both gas-solid (GS) and liquid-solid (LS) systems, in good agreement with the Richardson-Zaki 1 − ϕ n ${\left(1-\phi \right)}^{n}$ law. It was also noted that average velocity is independent of the boundary condition for both gas-solid (GS) and liquid-solid (LS) systems. The root mean square value of the solid volume fraction shows the increasing trend with volume fraction, caused by the many particle interactions. Furthermore, no-slip sidewalls were found to damp the velocity fluctuations quantitively, while following the well-known ϕ 1 / 2 ${\phi }^{1/2}$ scaling with volume fraction. Side walls were found to act as kinetic trap for the particles, damping the fluctuation near the walls and plateauing in the mid plane. These simulations showed that the GS system shows the higher solid fraction fluctuations that the LS system at the same Reynolds number, mainly because of the higher collision frequency (higher Stokes number) among the particles.

Explaining the magnetism of gold

2017 ◽  
Author(s):  
Robson de Farias
Keyword(s):  
Gas Phase ◽  
Computational Study ◽  
Formation Enthalpy ◽  
Gold Atom ◽  
Orbital Energy ◽  
Knudsen Effusion ◽  
Energy Diagram ◽  
Unpaired Electrons ◽  
The Difference ◽  
Good Agreement

<p>In the present work, a computational study is performed in order to clarify the possible magnetic nature of gold. For such purpose, gas phase Au<sub>2</sub> (zero charge) is modelled, in order to calculate its gas phase formation enthalpy. The calculated values were compared with the experimental value obtained by means of Knudsen effusion mass spectrometric studies [5]. Based on the obtained formation enthalpy values for Au<sub>2</sub>, the compound with two unpaired electrons is the most probable one. The calculated ionization energy of modelled Au<sub>2</sub> with two unpaired electrons is 8.94 eV and with zero unpaired electrons, 11.42 eV. The difference (11.42-8.94 = 2.48 eV = 239.29 kJmol<sup>-1</sup>), is in very good agreement with the experimental value of 226.2 ± 0.5 kJmol<sup>-1</sup> to the Au-Au bond<sup>7</sup>. So, as expected, in the specie with none unpaired electrons, the two 6s<sup>1</sup> (one of each gold atom) are paired, forming a chemical bond with bond order 1. On the other hand, in Au<sub>2</sub> with two unpaired electrons, the s-d hybridization prevails, because the relativistic contributions. A molecular orbital energy diagram for gas phase Au<sub>2</sub> is proposed, explaining its paramagnetism (and, by extension, the paramagnetism of gold clusters and nanoparticles).</p>

Effect of leakage and blockage on the acoustic behavior of particle filters

2019 ◽  
Vol 67 (6) ◽  
pp. 483-492
Author(s):  
Seonghyeon Baek ◽  
Iljae Lee
Keyword(s):  
Transfer Matrix ◽  
Particle Filters ◽  
Acoustic Analysis ◽  
Transmission Loss ◽  
One Dimensional ◽  
Filter System ◽  
The Difference ◽  
The One ◽  
Analytical Approaches ◽  
Good Agreement

The effects of leakage and blockage on the acoustic performance of particle filters have been examined by using one-dimensional acoustic analysis and experimental methods. First, the transfer matrix of a filter system connected to inlet and outlet pipes with conical sections is measured using a two-load method. Then, the transfer matrix of a particle filter only is extracted from the experiments by applying inverse matrices of the conical sections. In the analytical approaches, the one-dimensional acoustic model for the leakage between the filter and the housing is developed. The predicted transmission loss shows a good agreement with the experimental results. Compared to the baseline, the leakage between the filter and housing increases transmission loss at a certain frequency and its harmonics. In addition, the transmission loss for the system with a partially blocked filter is measured. The blockage of the filter also increases the transmission loss at higher frequencies. For the simplicity of experiments to identify the leakage and blockage, the reflection coefficients at the inlet of the filter system have been measured using two different downstream conditions: open pipe and highly absorptive terminations. The experiments show that with highly absorptive terminations, it is easier to see the difference between the baseline and the defects.

Effect of Magnetic Fields on the Resistance and Microstructure of Al-Cu Alloy during Solidification Processing

2011 ◽  
Vol 287-290 ◽  
pp. 2916-2920
Author(s):  
Chun Yan Ban ◽  
Peng Qian ◽  
Xu Zhang ◽  
Qi Xian Ba ◽  
Jian Zhong Cui
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Turning Points ◽  
Probe Method ◽  
Solidification Processing ◽  
Ac Magnetic Field ◽  
Dc Magnetic Field ◽  
Cu Alloy ◽  
The Difference ◽  
Good Agreement

The resistance of Al-21%Cu alloy under no magnetic field, DC magnetic field and AC magnetic field from liquid to solid was measured by a four-probe method. The difference of resistance versus temperature curves (R-T curves) was analyzed. It is found that the R-T curves of Al-21%Cu alloy are monotone decreasing and have two obvious turning points. Under DC magnetic field, the liquidus and solidus temperatures of the alloy both decrease, while under AC magnetic field, the liquidus and solidus temperatures both increase. There is a good agreement between the microstructure of quenching sample and R-T curves. The mechanism of the effect of magnetic fields was discussed.

scholarly journals Grounding semantic transparency in context

Morphology ◽  
2021 ◽  
Author(s):  
Rossella Varvara ◽  
Gabriella Lapesa ◽  
Sebastian Padó
Keyword(s):  
Large Scale ◽  
Point Of View ◽  
Distributional Semantics ◽  
Semantic Transparency ◽  
Inclusion Measure ◽  
The Difference ◽  
Semantic Point ◽  
The Many ◽  
The Relationship

AbstractWe present the results of a large-scale corpus-based comparison of two German event nominalization patterns: deverbal nouns in -ung (e.g., die Evaluierung, ‘the evaluation’) and nominal infinitives (e.g., das Evaluieren, ‘the evaluating’). Among the many available event nominalization patterns for German, we selected these two because they are both highly productive and challenging from the semantic point of view. Both patterns are known to keep a tight relation with the event denoted by the base verb, but with different nuances. Our study targets a better understanding of the differences in their semantic import.The key notion of our comparison is that of semantic transparency, and we propose a usage-based characterization of the relationship between derived nominals and their bases. Using methods from distributional semantics, we bring to bear two concrete measures of transparency which highlight different nuances: the first one, cosine, detects nominalizations which are semantically similar to their bases; the second one, distributional inclusion, detects nominalizations which are used in a subset of the contexts of the base verb. We find that only the inclusion measure helps in characterizing the difference between the two types of nominalizations, in relation with the traditionally considered variable of relative frequency (Hay, 2001). Finally, the distributional analysis allows us to frame our comparison in the broader coordinates of the inflection vs. derivation cline.

Local atomic structure in tetragonal pure ZrO2nanopowders

2010 ◽  
Vol 43 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Leandro M. Acuña ◽  
Diego G. Lamas ◽  
Rodolfo O. Fuentes ◽  
Ismael O. Fábregas ◽  
Márcia C. A. Fantini ◽  
...  
Keyword(s):  
Tetragonal Phase ◽  
Local Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Structures ◽  
Crystallite Sizes ◽  
Exafs Study ◽  
The Difference ◽  
X Ray Absorption ◽  
Good Agreement

The local atomic structures around the Zr atom of pure (undoped) ZrO2nanopowders with different average crystallite sizes, ranging from 7 to 40 nm, have been investigated. The nanopowders were synthesized by different wet-chemical routes, but all exhibit the high-temperature tetragonal phase stabilized at room temperature, as established by synchrotron radiation X-ray diffraction. The extended X-ray absorption fine structure (EXAFS) technique was applied to analyze the local structure around the Zr atoms. Several authors have studied this system using the EXAFS technique without obtaining a good agreement between crystallographic and EXAFS data. In this work, it is shown that the local structure of ZrO2nanopowders can be described by a model consisting of two oxygen subshells (4 + 4 atoms) with different Zr—O distances, in agreement with those independently determined by X-ray diffraction. However, the EXAFS study shows that the second oxygen subshell exhibits a Debye–Waller (DW) parameter much higher than that of the first oxygen subshell, a result that cannot be explained by the crystallographic model accepted for the tetragonal phase of zirconia-based materials. However, as proposed by other authors, the difference in the DW parameters between the two oxygen subshells around the Zr atoms can be explained by the existence of oxygen displacements perpendicular to thezdirection; these mainly affect the second oxygen subshell because of the directional character of the EXAFS DW parameter, in contradiction to the crystallographic value. It is also established that this model is similar to another model having three oxygen subshells, with a 4 + 2 + 2 distribution of atoms, with only one DW parameter for all oxygen subshells. Both models are in good agreement with the crystal structure determined by X-ray diffraction experiments.

The paleomagnetism of Huronian red beds and Nipissing diabase; Post-Huronian Igneous Events and apparent polar path for the interval −2300 to −1500 Ma for Laurentia

1976 ◽  
Vol 13 (6) ◽  
pp. 749-773 ◽  
Author(s):  
J. L. Roy ◽  
P. L. Lapointe
Keyword(s):  
High Stability ◽  
Vertical Axis ◽  
Time Range ◽  
High Latitudes ◽  
Red Beds ◽  
Two Stage ◽  
Low Latitudes ◽  
The Many ◽  
Age Determinations ◽  
Good Agreement

Thermal, chemical, and alternating field (and two-stage) cleaning treatments of Huronian sediments and Nipissing diabase (which intrudes the sediments) from the Cobalt area yield five directions of magnetizations (A–E) of high stability; A, B, C, and E are found in the sediments, and C, D, and E in the diabase. It is suggested that magnetization B (337°, +52°; α95 = 8°; pole 158 °E, 67 °N) was acquired shortly after deposition of the Firstbrook beds [Formula: see text]; magnetization C (259°, +82°; α95 = 5°; pole 258 °E, 42 °N), found in both the diabase and sediments in contact with the diabase, was acquired during cooling following emplacement of the diabase [Formula: see text]; and magnetizations D and E, yielding poles at 264 °E, 15 °S and 000°, 09 °N respectively, were produced during the Hudsonian orogeny (−1850 to −1700 Ma). This interpretation resolves the previous inconsistencies between poles and age determinations. Good agreement between results from the Nipissing diabase and other igneous bodies indicate that widespread igneous events occurred in the time range approximately −2200 to −2100 Ma, immediately following deposition of Huronian sediments. This is referred to as 'Post-Huronian Igneous Events'. A proposed apparent polar path relative to Laurentia shows two distinct motions; for the 2300–1850 Ma interval, a latitudinal change (roughly along longitude 250° E) from high [Formula: see text] to low [Formula: see text] latitudes and, for the 1850–1500 Ma interval, a displacement along the present-day equator with first an eastward motion to about 000° longitude followed by a westward motion to 240° E longitude; the apex of the eastward excursion is given a date of [Formula: see text]. It is possible that this reflects a rotation of Laurentia about a vertical axis at the time of and following the Hudsonian orogeny. Subsequent uplift and cooling would explain the many overprinted stable magnetizations yielding poles distributed along the equator (track 4). Latitude maps indicate that Laurentia was in high latitudes from 2200–2000 Ma and in intermediate to low latitudes from 1900–1500 Ma.

scholarly journals THE METHOD OF INCREMENTS — A WAVEFUNCTION-BASED AB-INITIO CORRELATION METHOD FOR SOLIDS

2007 ◽  
Vol 21 (13n14) ◽  
pp. 2204-2214 ◽  
Author(s):  
BEATE PAULUS
Keyword(s):  
Experimental Data ◽  
Ab Initio ◽  
Ground State ◽  
Infinite System ◽  
Correlation Energy ◽  
Correlation Method ◽  
Many Body ◽  
Hartree Fock ◽  
The Many ◽  
Good Agreement

The method of increments is a wavefunction-based ab initio correlation method for solids, which explicitly calculates the many-body wavefunction of the system. After a Hartree-Fock treatment of the infinite system the correlation energy of the solid is expanded in terms of localised orbitals or of a group of localised orbitals. The method of increments has been applied to a great variety of materials with a band gap, but in this paper the extension to metals is described. The application to solid mercury is presented, where we achieve very good agreement of the calculated ground-state properties with the experimental data.

The derivation of the rotational potential function from atom–atom potentials. III. Borohydride compounds

1988 ◽  
Vol 66 (4) ◽  
pp. 791-793 ◽  
Author(s):  
David Smith
Keyword(s):  
Transition Temperature ◽  
Experimental Method ◽  
Potential Function ◽  
Ground Level ◽  
Potential Functions ◽  
The Difference ◽  
Level Degeneracy ◽  
Entropy Of Transition ◽  
Good Agreement

The rotational potential functions for the borohydride ion embedded in potassium and rubidium halides are derived from atom–atom potentials of the Buckingham (exp-6) type. The librational frequencies computed from the potential functions are in good agreement with the observed frequencies. The potential functions for rubidium and potassium borohydrides derived from the atom–atom potentials yield librational frequencies that are about 10% higher than the observed values. Since the entropy of transition for potassium and rubidium borohydrides is less than expected, there is a possibility that there is some ordering of the borohydride ions above the transition temperature. An experimental method is presented for studying the ordering of the borohydride ions based on the difference in the ground level degeneracy of a tetrahedral ion in ordered and disordered states.

Thermodynamical Calculations and Experimental Confirmation about the Mg-Al-Spinel Reaction Path in the Sol-Gel-Process

2006 ◽  
Vol 317-318 ◽  
pp. 135-138 ◽  
Author(s):  
Wilfried Wunderlich ◽  
Krupathi Vishista ◽  
Francis D. Gnanam ◽  
Daniel Doni Jayaseelan
Keyword(s):  
Thermal Analysis ◽  
Reaction Path ◽  
Sol Gel ◽  
Chemical Processing ◽  
Aluminium Isopropoxide ◽  
Spinel Formation ◽  
Sol Gel Process ◽  
Wet Chemical ◽  
Enthalpy Data ◽  
Good Agreement

The aim of this research is, to clarify which route the sol-gel-process is taking in the case of a Al-Mg-spinel slurry, in particular, whether the hydrolysis reaction or the spinel formation is faster and which of the intermediate hydroxide phases Al(OH)3, and Mg(OH)2, or MgO and Al2O3 or MgAl2O4H2O are formed during the spinel formation. The spinel-alloy was produced using the polymeric route during wet chemical processing. Aluminium-isopropoxide was hydrolyzed in order to form the boehmite-sol and then the same amount of magnesia was added and mixed. This sol precipitated as boehmite (AlOOH) and brucite (Mg(OH)2) after ageing for 12h as confirmed by differential thermal analysis (DTA), and differential thermal gravity (DTG) measurements. After that, the powders were subsequently annealed at 900oC for 3h in air and observed by TEM. Calculations using thermodynamic enthalpy data are in good agreement with the experiments and can be used to predict reaction paths in other system as well.

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