The effect of decationation of hydroxylated HNaY zeolites on their interaction with ethylene and propylene. hydrogen complexes, oligomeration and isotope exchange

1980 ◽  
Vol 45 (11) ◽  
pp. 3101-3115 ◽  
Author(s):  
Ludmila Kubelková ◽  
Jana Nováková ◽  
Zdeněk Dolejšek ◽  
Pavel Jírů
Keyword(s):  
Isotope Exchange ◽  
Decisive Role ◽  
Single Step ◽  
Hydroxyl Groups ◽  
Isotope Exchange Reaction ◽  
Factors Affecting ◽  
Step Mechanism ◽  
Formed Hydrogen ◽  
Lower Basicity ◽  
Multiple Step

The effect of decationation on the interaction of propylene and ethylene with the hydroxylated forms of HNaY zeolites has been studied. The compounds formed in the zeolite cavities were studied using their infrared spectra, the composition of the gaseous phase was followed by mass spectrometry. The results showed that among factors affecting the interaction with propylene properties of hydroxyl groups play the decisive role. With the increasing decationation of the zeolite the strength of the OH bond in the hydrogen complex of the large-cavity hydroxyls with propylene decreased and the rate of propylene oligomeration at 310 K as well as the isotope exchange rate of propylene-d6 with the zeolite hydroxyls at 570 K increased. The propylene isotope exchange reaction proceeded by the multiple-step mechanism. In the case of ethylene only the physical sorption with a non-specific character was observed at 310 K. The adsorbed amount increased with the increasing content of Na+ ions in the zeolite (with the decreasing decationation). A part of the adsorbed molecules formed hydrogen complexes with hydroxyls of large cavities. The observed lower weakening of the OH bond was in agreement with the lower basicity of ethylene if compared with propylene. The isotope exchange of ethylene-d4 with the zeolite hydroxyls proceeded by a single-step mechanism, it had an autocatalytic character and its rate was 70 times lower than that of the isotope exchange of propylene-d6 with OH.

THE PREDICTIVE CONTENT OF DISAGGREGATED NORMAL INCOME: An Empirical Study in the JSX

2003 ◽  
Vol 5 (3) ◽  
pp. 363 ◽  
Author(s):  
Slamet Sugiri
Keyword(s):  
Linear Regression ◽  
Regression Models ◽  
Stock Exchange ◽  
Manufacturing Firms ◽  
Single Step ◽  
Model Parameters ◽  
Linear Regression Models ◽  
Operating Income ◽  
Predictive Content ◽  
Multiple Step

The main objective of this study is to examine a hypothesis that the predictive content of normal income disaggregated into operating income and nonoperating income outperforms that of aggregated normal income in predicting future cash flow. To test the hypothesis, linear regression models are developed. The model parameters are estimated based on fifty-five manufacturing firms listed in the Jakarta Stock Exchange (JSX) up to the end of 1997.This study finds that empirical evidence supports the hypothesis. This evidence supports arguments that, in reporting income from continuing operations, multiple-step approach is preferred to single-step one.

scholarly journals One-Pot Hydrothermal Synthesis of Victoria Green (Ca3Cr2Si3O12) Nanoparticles in Alkaline Fluids and Its Colour Hue Characterisation

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 521
Author(s):  
Juan Carlos Rendón-Angeles ◽  
Zully Matamoros-Veloza ◽  
Jose Luis Rodríguez-Galicia ◽  
Gimyeong Seong ◽  
Kazumichi Yanagisawa ◽  
...  
Keyword(s):  
Near Infrared ◽  
Single Step ◽  
Spectral Space ◽  
Infrared Reflectance ◽  
Hydrothermal Preparation ◽  
Near Infrared Reflectance ◽  
One Pot ◽  
Factors Affecting ◽  
B Values ◽  
Alkaline Conditions

One-pot hydrothermal preparation of Ca3Cr2Si3O12 uvarovite nanoparticles under alkaline conditions was investigated for the first time. The experimental parameters selected for the study considered the concentration of the KOH solvent solution (0.01 to 5.0 M), the agitation of the autoclave (50 rpm), and the nominal content of Si4+ (2.2–3.0 mole). Fine uvarovite particles were synthesised at 200 °C after a 3 h interval in a highly concentrated 5.0 M KOH solution. The crystallisation of single-phase Ca3Cr2Si3O12 particles proceeded free of by-products via a one-pot process involving a single-step reaction. KOH solutions below 2.5 M and water hindered the crystallisation of the Ca3Cr2Si3O12 particles. The hydrothermal treatments carried out with stirring (50 rpm) and non-stirring triggered the crystallisation of irregular anhedral particles with average sizes of 8.05 and 12.25 nm, respectively. These particles spontaneously assembled into popcorn-shaped agglomerates with sizes varying from 66 to 156 nm. All the powders prepared by the present method exhibited CIE-L*a*b* values that correspond to the Victoria green colour spectral space and have a high near infrared reflectance property. The particle size and structural crystallinity are factors affecting the Victoria pigment optical properties, such as CIE-L*a*b* values, green tonality, and near-infrared reflectance.

Isotope exchange reaction on Li2ZrO3

1997 ◽  
Vol 250 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Atsushi Baba ◽  
Masabumi Nishikawa ◽  
Takanori Eguchi
Keyword(s):  
Exchange Reaction ◽  
Isotope Exchange ◽  
Isotope Exchange Reaction

Hydrogen isotope exchange between D2 and H2O catalyzed by platinum plate

1989 ◽  
Vol 67 (5) ◽  
pp. 857-861 ◽  
Author(s):  
Shin-Ichi Miyamoto ◽  
Tetsuo Sakka ◽  
Matae Iwasaki
Keyword(s):  
Kinetic Model ◽  
Exchange Reaction ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Hydrogen Adsorption ◽  
Platinum Catalyst ◽  
Isotope Exchange Reaction ◽  
Hydrogen Isotope Exchange ◽  
Supported Platinum

The reaction rate of hydrogen isotope exchange between D2 and H2O catalyzed by platinum plate is studied. The exchange reaction is described with the kinetic model which is the modification of that for the exchange reaction catalyzed by alumina-supported platinum catalyst. For the comparison of experimental results with this model relative amount of the number of sites for hydrogen adsorption was estimated from the initial rate of hydrogen isotope exchange between H2 and D2 on the same surface. The results show that the kinetic model is applicable for the plate catalyst if the number of the sites for hydrogen absorption, which is very sensitive to the surface state of the catalyst, was estimated not from the macroscopic surface area but from our scheme. Keywords: hydrogen isotope exchange reaction, platinum plate as catalyst.

scholarly journals Factors Affecting Unmet Need of Family Planning Among Married Tharu Women of Dang District, Nepal

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chet Kant Bhusal ◽  
Sigma Bhattarai
Keyword(s):  
Family Planning ◽  
Reproductive Health ◽  
Strategic Behavior ◽  
Universal Access ◽  
Unmet Need ◽  
Decisive Role ◽  
Secondary Level ◽  
Cross Sectional ◽  
Factors Affecting ◽  
Communication Program

Background. Increase in population plays a decisive role in providing universal access to reproductive health; however, there is very limited evidence about the reason of unmet need among marginalized and tribal communities such as Tharus. This study aimed to determine the factors affecting unmet need of family planning among married Tharu women of Dang, Nepal. Methods. Community-based cross-sectional household survey among 650 married Tharu women of age group 15-49 in October 2015 to April 2016 was conducted in Dang district, Nepal. Randomly 3 wards were selected from each Tulsipur municipality, Hekuli Village Development Committee, and Pawan Nagar VDC. Results. The mean age and parity were 30±7.31 and 2±0.69, respectively. Out of 650 women, 47% were using contraceptives. Westoff model was used for calculating total unmet need which is 49%, where unmet need for limiting and spacing was 27% and 22%, respectively. Hence after combining the current users and total unmet need, total demand for family planning was 96%. After adjustment, significant relation was observed between number of living sons ≥ 1 and unmet need of family planning (OR= 0.4; CI=0.2-0.8, p=0.01 ), similarly for women education; lower secondary level (OR=0.3; CI=0.1-0.6, p=0.01) and secondary (OR=0.1; CI=0.03-0.4, p=0.01); husband education, lower secondary level (OR=0.3; CI=0.1-0.6, p=0.01) and secondary (OR=0.4; CI= 0.2-0.9, p=0.04); and husband occupation, wage labor (OR=0.6; CI=0.4-0.99, p=0.05). In addition, having very good knowledge about method was also significantly associated (OR=0.49; CI= 0.2-0.97, p= 0.04). Conclusion. Unmet need of family planning was significantly higher among less than secondary educated women. It is also predisposed by spouse education, partner’s occupation, and number of living sons. This study concerns the need for all stake holders to focus on strategic behavior communication program regarding reproductive health.

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