Search Results
You are looking at 1 - 8 of 8 items for
- Author or Editor: P. Albert x
- Refine by Access: All Content x
Over 30 white and coloured titanium enamels of different origin were tested with a derivatograph. Thermoceram crucibles were used, which enabled the tests to be interrupted when a change was indicated by the DTA curve. The crucible was removed from the derivatograph, and the sample pulverized and studied by X-ray diffraction method. A major difference compared to previous observations was the fact that the exothermic peak indicating the anatase-rutile transformation was also found on the DTA curves of certain anatase-type enamels. With these enamels the temperature relating to the start of the transformation peak was regarded as the critical temperature, as at a temperature below this the enamel was stable, but above it unstable.
Abstract
The determination of Ir and Pt in rhodium neutron monitors was investigated via192Ir and199Au after neutron activation, via191Pt and194Au–196Au after proton activation. Ir was determined by instrumental NAA. A chemical separation of gold, with a yield measurement method by a radioactive tracer, was developed for platinum determination after neutron or proton irradiation.
Iris rich meadows have been introduced in the last couple of years as Iridetum sibiricae in Hungary, but have not been confirmed by studying sampling plots. It is a rare, edaphic, semi-natural edge vegetation of subcontinental climatic zone on alluvial surfaces. In our study characteristic species composition and vegetation structure integrated with ecological considerations are described. Analyses were carried out by phytosociological tables, chorographical types, relative ecological indicator values and social behaviour types. Most of the vegetation phenomena indicated in general descriptions and overviews are supported. This community is species rich, 3-layered vegetation with a multi-dominating species pool. High proportions of constant and accidental species, Molinietalia and indifferent coenological elements, Eurasian and European and sub-Mediterranean distribution types, competitors and specialists have large importance in this vegetation structure. Its life form strategy is based on the balance between hemicryptophytes and geophytes. Using ecological indicator values, habitat characteristics and phytogeographical status of the association had been revealed.
Formaldehyde and some fully n-methylated substances in boar seminal fluids
Short Communication
On the basis of recent observations it is supposed that seminal fluids may contain - mainly in hydroxymethyl groups - formaldehyde (HCHO) and quaternary ammonium compounds as potential HCHO generators, therefore, preliminary investigations were carried out for the identification of these compounds in pig seminal fluids using OPLC, HPLC and MALDI MS techniques. The fresh pig seminal fluid was frozen in liquid nitrogen, powdered and aliquots (0.25 g) were treated with 0.7 ml ethanolic dimedone solution. The suspension was centrifuged and the clear supernatant was used for analysis by OPLC or after dilution with HPLC or MALDI MS technique. After OPLC separation of formaldemethone the fully N-methylated compounds which are stayed on the start point were separated by OPLC using an other eluent system. It has been established that the HCHO is really a normal component of the pig seminal fluid, as well. It can be isolated and identified in dimedone adduct form. The measurable amount of HCHO depended on the concentration applied of dimedone. According to OPLC and MALDI MS investigations L-carnitine is the main quaternary ammonium compound in pig seminal fluid which can generate a protection of the sperm cells against environmental and other influences. Considerable differences have been found among individuals concerning concentrations of quaternary ammonium compounds in the seminal fluid of pigs.
Abstract
A novel nonlinear optical semi-organic single crystal of l-histidine methyl ester dihydrochloride was grown by slow evaporation solution growth method at an ambient temperature. The grown crystal was characterized by single crystal X-ray diffraction. Functional groups and the modes of vibrations were identified by FT–IR spectroscopy. The chemical composition of the crystal was confirmed by Energy dispersive X-ray analysis. The optical behavior of the crystal was examined by UV spectral analysis, which shows the absence of absorption between the wavelengths ranging from 230 to 1000 nm. The optical band gap of the grown crystal was estimated and is found to be 5.35 eV. The thermal behavior of the crystal was investigated by thermogravimetric and differential thermal analyses. The nonlinear optical property of the grown crystal was confirmed by the powder technique of Kurtz and Perry.
Different osmotic agents (OA), such as potassium acetate (CH3COOK), potassium carbonate (K2CO3) and ammonium nitrate (NH4NO3), have been examined as alternatives to the traditionally used calcium chloride (CaCl2) for osmotic distillation concentrating of clarified and pre-concentrated sour cherry (Prunus cerasus L.) juice. Comparison of the process performances based on the permeate fluxes has been carried out. Regarding the permeate flux results, simplified estimation of the overall mass transfer coefficient of the most effective osmotic agent and the reference (CaCl2) solution has been also performed. Furthermore, analytical methods such as total antioxidant activity (TAA) and total polyphenolic content (TPC) using spectrophotometric assays have been also carried out to evaluate the effect of the osmotic distillation on the valuable compounds content of concentrated sour cherry juice. CH3COOK was found to be the most effective, resulted more than 25% higher permeate flux during the sour cherry juice concentration. K2CO3 and NH4NO3 were less effective. The simplified mass transfer estimation showed that the CH3COOK is more effective only at near saturated concentrations compared to the CaCl2. Regarding the TAA and TPC contents, a significant loss was found in case of all OAs during the concentration procedures.
In the present paper we report original thousand-seed weight data for the flora of the Pannonian Basin. Our goal was to demonstrate the usefulness of seed weight databases by analysing seed weight data in relation to social behaviour types and life forms. We specifically asked the following questions: (i) how the seed weights are related to social behaviour type categories; (ii) how the life form of the species influences seed weight differences between respective social behaviour types? Own weight measurements are provided for 1,405 taxa; and for 187 taxa we published seed weight data for the first time: these were mostly endemics, orchids and/or species with Pontic, Caspian or continental distribution. Several taxonomic or functional groups are underrepresented in our database, like aquatic plants, rare arable weeds and sub-Mediterranean species. Problematic taxa, some difficult-to-harvest species or species with low seed production and cultivated adventives are also underrepresented. We found that the plant strategies expressed by social behaviour types were significantly different in terms of seed weights. The lowest seed weight scores were found for natural pioneers, whereas the highest ones were found for adventives and introduced cultivated plants. Short-lived herbaceous species had significantly higher seed weight scores than herbaceous perennials. No significant differences were found between specialists and generalists within the stress tolerant group. We found that short-lived graminoids possess heavier seeds than perennial graminoids, perennial and annual forbs. Naturalness scores were negatively correlated with seed weights. Our findings showed that seed collections and databases are not only for storing plant material and seed weight data, but can be effectively used for understanding ecological trends and testing plant trait-based hypotheses. Even the identified gaps underline the necessity of further seed collection and measurements.
