240 research outputs found
4-(3-EthÂoxy-4-hydroxyÂstyrÂyl)-1-methylÂpyridinium tosylÂate monohydrate
In the title compound, C16H18NO2
+·C7H7O3Sâ·H2O, the dihedral angle between the pyridyl and benzene rings of the pyridinium cation is 0.2â
(1)°. The benzene ring of the tosylÂate anion makes a dihedral angle of 4.8â
(2)° with the best mean plane of the pyridinium cation. The pyridinium cation and the tosylÂate anion are hydrogen bonded to the water molÂecule, and the crystal packing is further stabilized by interÂmolecular CâHâŻO and ÏâÏ interÂactions [centroidâcentroid separations of 3.648â
(3) and 3.594â
(2)â
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Corrosion Inhibition Studies of Mild Steel in Acid Medium Using Musa Acuminata Fruit Peel Extract
Abstract: The inhibition effect of unripe fruit peel extract of Musa acuminata (Cultivar variety -Nendran) (MNP) on corrosion of mild steel in 1 N HCl has been investigated by weight loss and electrochemical impedance spectroscopy (EIS) with various concentrations of the extract. The effect of temperature on the corrosion inhibition of mild steel in the temperature range of 30 °C -80 °C was carried out. The results indicate that MNP extract act as an effective inhibitor in the acid environment and is of mixed type inhibitor having efficiency as high as 96% at 2% inhibitor concentration. The inhibition efficiency of MNP extract increases with the increase of concentration but decreases with the increase in temperature. The inhibitor achieves its inhibition by physical adsorption of nutrients of the peel extract on the surface of the mild steel. The experimental data revealed that the adsorption occurred according to the Langmuir and Temkin adsorption isotherm
An electron paramagnetic resonance study of Pr_{0.6}Ca_{0.4}MnO_{3} across the charge ordering transition
We report the first electron paramagnetic resonance studies of single
crystals and powders of Pr_{0.6}Ca_{0.4}MnO_{3} in the 300-4.2 K range,
covering the charge ordering transition at ~ 240 K and antiferromagnetic
transition (T_N) at ~ 170 K. The asymmetry parameter for the Dysonian single
crystal spectra shows anomalous increase at T_{co}. Below T_{co} the g-value
increases continuously, suggesting a gradual strengthening of orbital ordering.
The linewidth undergoes a sudden increase at T_{co} and continues to increase
down to T_N. The intensity increases as the temperature is decreased till
T_{co} due to the renormalization of magnetic susceptibility arising from the
build up of ferromagnetic correlations. The value of the exchange constant, J,
is estimated to be 154 K.Comment: Uses Revtex3.
Cooling rate dependence of the antiferromagnetic domain structure of a single crystalline charge ordered manganite
The low temperature phase of single crystals of NdCaMnO
and GdCaMnO manganites is investigated by squid
magnetometry. NdCaMnO undergoes a charge-ordering
transition at =245K, and a long range CE-type antiferromagnetic state
is established at =145K. The dc-magnetization shows a cooling rate
dependence below , associated with a weak spontaneous moment. The
associated excess magnetization is related to uncompensated spins in the
CE-type antiferromagnetic structure, and to the presence in this state of
fully orbital ordered regions separated by orbital domain walls. The observed
cooling rate dependence is interpreted to be a consequence of the rearrangement
of the orbital domain state induced by the large structural changes occurring
upon cooling.Comment: REVTeX4; 7 pages, 4 figures. Revised 2001/12/0
Magnetoelectric effects of nanoparticulate Pb(Zr0.52Ti0.48)O3-NiFe2O4 composite films
We fabricated Pb(Zr0.52Ti0.48)O3-NiFe2O4 composite films consisting of
randomly dispersed NiFe2O4 nanoparticles in the Pb(Zr0.52Ti0.48)O3 matrix. The
structural analysis revealed that the crystal axes of the NiFe2O4 nanoparticles
are aligned with those of the ferroelectric matrix. The composite has good
ferroelectric and magnetic properties. We measured the transverse and
longitudinal components of the magnetoelectric voltage coefficient, which
supports the postulate that the magnetoelectric effect comes from direct stress
coupling between magnetostrictive NiFe2O4 and piezoelectric Pb(Zr0.52Ti0.48)O3
grains.Comment: 11 pages, 4 figure
Identifying the seeding signature in cloud particles from hydrometeor residuals
Cloud seeding experiments for modifying clouds and precipitation have been underway for nearly a century; yet practically all the attempts to link precipitation enhancement or suppression to the presence of seeding materials within clouds remain elusive. In 2019, the CloudâAerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) investigated residuals of cloud hydrometeors in seeded and non-seeded clouds with an airborne mini aerosol mass spectrometer (mAMS). The mAMS was utilized in conjunction with a counterflow virtual impactor (CVI) inlet with a cutoff diameter size of approximately 7â”m. The evaporated cloud droplets from the CVI inlet as cloud residuals were evaluated through the mAMS. The chlorine (Cl) associated with hygroscopic materials, i.e. calcium chloride (CaCl2) and potassium (K), which serve as the oxidizing agents in the flares, is found in relatively higher concentrations in the seeded clouds compared to the non-seeded clouds. In convective clouds, Cl and K as cloud residuals were found even at a vertical distance of 2.25âkm from the cloud base. Major findings from the seeding impact are an increase in the number concentration of small (<â20â”m) droplets and an indication of raindrop formation at 2.25âkm above the cloud base. It is demonstrated that the seed particle signature can be traced inside clouds along with the microphysical impacts.</p
Three-dimensional lanthanide-organic frameworks based on di-, tetra-, and hexameric clusters
Three-dimensional lanthanide-organic frameworks formulated as (CH3)2NH2[Ln(pydc)2] · 1/2H2O [Ln3+ ) Eu3+ (1a)
or Er3+ (1b); pydc2- corresponds to the diprotonated residue of 2,5-pyridinedicarboxylic acid (H2pydc)], [Er4(OH)4(pydc)4(H2O)3] ·H2O
(2), and [PrIII
2PrIV
1.25O(OH)3(pydc)3] (3) have been isolated from typical solvothermal (1a and 1b in N,N-dimethylformamide -
DMF) and hydrothermal (2 and 3) syntheses. Materials were characterized in the solid state using single-crystal X-ray diffraction,
thermogravimetric analysis, vibrational spectroscopy (FT-IR and FT-Raman), electron microscopy, and CHN elemental analysis.
While synthesis in DMF promotes the formation of centrosymmetric dimeric units, which act as building blocks in the construction
of anionic â
3{[Ln(pydc)2]-} frameworks having the channels filled by the charge-balancing (CH3)2NH2
+ cations generated in situ by
the solvolysis of DMF, the use of water as the solvent medium promotes clustering of the lanthanide centers: structures of 2 and 3
contain instead tetrameric [Er4(Ό3-OH)4]8+ and hexameric |Pr6(Ό3-O)2(Ό3-OH)6| clusters which act as the building blocks of the networks,
and are bridged by the H2-xpydcx- residues. It is demonstrated that this modular approach is reflected in the topological nature of
the materials inducing 4-, 8-, and 14-connected uninodal networks (the nodes being the centers of gravity of the clusters) with
topologies identical to those of diamond (family 1), and framework types bct (for 2) and bcu-x (for 3), respectively. The
thermogravimetric studies of compound 3 further reveal a significant weight increase between ambient temperature and 450 °C with
this being correlated with the uptake of oxygen from the surrounding environment by the praseodymium oxide inorganic core
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Track A Basic Science
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd
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