Search results for "composition"

Thermal stability of PP with acetylated sisal fiber: Romero Garc�a kinetic method

2003

This work deals the effect of acetylated and non-acetylated sisal fiber 011 thermal degradation of polypropylene. Applying the R-G method at constant conversion levels of 0.1, 0.3, 0.5, 0.7 and 0.9 to thermograms of the ”PP/untreated sisal fiber” blend, E, values of 99, 213, 224, 187, and 145 kJ/mol were obtained, whereas they were 99, 299, 255, 205, 154 kJ/mol for the “PP/treated sisal fiber” blend. On the other hand, with the R-G method at constant temperature, activation energies within the range of 156-417 kJ/mol were obtained for the “PP/treated sisal fiber” blend and within the range of 126-344 kJ/mol for the “PP/untreated sisal fiber” blend. Additionally, the method establishes as do…

Structure of isotactic polypropylene–hydrogenated oligo(cyclopentadiene) (iPP–HOCP) blends Part II. HOCP-rich blends

2000

Abstract Blends of isotactic polypropylene (iPP) and hydrogenated oligo(cyclopentadiene) (HOCP) were investigated to gain structural information by means of both SAXS and SANS techniques. The composition range (from 30 to 60% w/w HOCP content) and the temperature range (between 25 and 160°C) were chosen in order to cover the miscibility gap in the phase diagram of the material system. In a previous report, blends lying outside the miscibility gap have been investigated and the corresponding SAXS patterns were interpreted in terms of a pseudo-two phase model. For the SAXS patterns, blends lying inside the miscibility gap are rather hard to be interpreted in terms of such a model. On the othe…

Oblicze demograficzne Opola na początku XXI wieku

2019

Opole jako stolica regionu, który w przeszłości zmieniał przynależność państwową i zasięg terytorialny, co skutkowało wielokrotnymi przesunięciami granic wewnętrznych i zewnętrznych oraz ulegał przemianom kulturowo-cywilizacyjnym, współcześnie doświadcza gwałtownych przeobrażeń społecznych. Jednym z głównych jego problemów jest niekorzystny przebieg procesów demograficznych na przełomie XX i XXI w., m.in. depopulacja. Aktualny obraz demograficzny miasta ukształtowało wiele czynników występujących w przeszłości, a zwłaszcza po zakończeniu II wojny światowej, których skutki miasto nadal odczuwa. Celem artykułu było ukazanie depopulacji wraz z towarzyszącymi jej negatywnymi zjawiskami i proces…

A simple approach towards one-dimensional mesoporous carbon with superior electrochemical capacitive activity.

2009

One-dimensional (1D) mesoporous carbons with highly ordered 3D interconnected pore structure and large-diameter pore size (10–20 nm) have been synthesized by a simple precursor-controlled thermolysis approach; such unique carbonaceous frameworks show superior capacitive behavior in electrochemical double-layer capacitors.

Determination of tocopherols in vegetable oils by CEC using methacrylate ester-based monolithic columns

2007

The separation and determination of tocopherols (Ts) in vegetable oils by CEC using methacrylate ester-based monolithic columns has been developed. The effects of pore size of the monolithic columns were studied, and the composition of mobile phase was optimized. The optimal pore size of the monolith was obtained with 12 wt% 1,4-butanediol in the polymerization mixture. Excellent resolution between tocopherols was achieved within 10 min analysis time with a 99:1 v/v MeOH-aqueous buffer containing 5 mM tris(hydroxymethyl)aminomethane at pH 8.0. The LODs were lower than 2.3 microg/mL, and interday and column-to-column reproducibilities at 25 microg/mL were better than 5.6%. Using a 93:7 v/v M…

Prevention, diagnosis, and treatment of obesity. 2016 position statement of the Spanish Society for the Study of Obesity.

2017

Spectra of Positrons Lifetimes in Choose Gel Drugs

2006

antiphlogistic drugs were investigated. The basic components in them were sodium salts of diclophenac and they difiered from one another with the chemical composition of other components. It was found that in all of the investigated spectra there occurred a component which testifled to the formation of positronium. The difierences in the values of ortho-Ps component lifetimes and their intensity can be attributed to the presence of ingredients modifying the efiects of the drug.

Chemistry, mineralogy and radioactivity inposidonia oceanicameadows from North-Western Sicily

2004

This paper presents measurements of major, minor, metal trace elements and radionuclides in sediments and in Posidonia oceanica samples from north-western Sicily (Italy). The mineralogical and chemical composition of sediments were determined by X-ray diffraction and X-ray fluorescence techniques, respectively. A flame atomic absorption spectrophotometry was used to measure concentrations of Cu, Zn, Cd and Pb in P. oceanica samples and in sediments. Specific activities of selected radionuclides have been determined by high-resolution gamma spectrometry. Standard statistical analysis was used to assess correlations between different elements and different sample types.

Multiconfigurational second-order perturbation study of the decomposition of the radical anion of nitromethane

2004

The doublet potential energy surfaces involved in the decomposition of the nitromethane radical anion (CH(3)NO(2) (-)) have been studied by using the multistate extension of the multiconfigurational second-order perturbation method (MS-CASPT2) in conjunction with large atomic natural orbital-type basis sets. A very low energy barrier is found for the decomposition reaction: CH(3)NO(2) (-)--[CH(3)NO(2)](-)--CH(3)+NO(2) (-). No evidence has been obtained on the existence of an isomerization channel leading to the initial formation of the methylnitrite anion (CH(3)ONO(-)) which, in a subsequent reaction, would yield nitric oxide (NO). In contrast, it is suggested that NO is formed through the …

Two Cases from Central America: Attitudes of Political Elites in Panama and Guatemala

2020

Panama and Guatemala represent two very different political experiences in the Central American region. Also their political elites show different patterns. The disparities in their recent histories, their economies, and their formal and informal institutions have impacted on their representation and composition of their elites. Both countries are characterized by the influence of economy on politics. However, while in Panama the wealth of the canal has contributed to political stability, in Guatemala the old oligarchies have preserved its power by preventing the strengthening of institutions. Nonetheless, in spite of the issues that affect each country, there may be some similarities. One …