Laboratory Test of the Soil Compaction Malý, Vlastimil; Tóth, František; Mareček, Jan ...
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis,
2015, Letnik:
63, Številka:
1
Journal Article
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This paper presents the mechanical properties of soil. In order to determine the properties of soil under laboratory conditions, we made use of a special measuring device, viz. a bevameter. Two types ...of soil with different levels of moisture were examined and their mechanical properties determined. Measurements were taken of non pressed and compressed soil. A measuring network was set up, consisting of measuring and recording devices. In the course of measuring, the force and penetration depth of the pressing plate were recorded simultaneously. Four different diameters of pressing plate were used, resp. 25, 38, 50 and 70 mm. The pressure on the contact area was calculated after completion of the measurements, and the relationships between pressure and penetration depth were presented graphically.
The paper describes the CEFME Portal (Central European Forum on Military Education) for military universities cooperation. The goal of the CEFME system is to support the cooperation among the ...community of ten universities in education, research, social area, and staff and students exchange. The system is derived from the MilUNI (Military Universities), a knowledge management system (KMS), based on Topic Maps theory using the ATOM software. Special attention is given to the new features of the KMS and the adoption of the portal by users. The related work is analyzed. Discussion and future work direction closes the paper.
This contribution brings an evaluation of basic material C 45 heat treated and hardened, 16MnCr5 as basic material carburized and hardened and weld deposits of selected additional hardened materials. ...Results obtained for basic material are compared with results on materials of surfaced layers. This enables us to predict certain characteristics of friction pairs under conditions of particular friction node. The tribologic experiment was carried out on device, which belongs to the category of "pin-disk" test devices. The resistance of the selected materials was evaluated concerning weight loss and energy issues. It was observed that combinations of material C508 + C64 and material RD1 give the best results for both categories of test samples under the experimental conditions. Wear resistance of this combination of materials was higher than 43 %. The wear resistance was calculated from energy consumed to remove one unit of metal from the surface.
U ovom se prilogu daje procjena osnovnog materijala C45 toplinski obrađenog i kaljenog, 16MnCr5 kao osnovnog materijala pougljičenog i kaljenog te materijala zavara izabranih dodatnih kaljenih ...materijala. Rezultati dobiveni za osnovni material uspoređeni su s rezultatima dobivenim na materijalima površinskih slojeva. To nam omogućuje predviđanje nekih karakteristika tarnih parova u uvjetima određenog tarnog čvora. Tribološki eksperiment proveden je na uređaju koji pripada kategoriji "trn-disk" uređaja za ispitivanje. Otpornost izabranih materijala procijenjena je u odnosu na gubitak težine i pitanja energije. Ustanovljeno je da kombinacije materijala C508 + C64 i materijala RD1 daju najbolje rezultate za obje kategorije ispitnih uzoraka u eksperimentalnim uvjetima. Otpornost na trošenje te kombinacije materijala bila je viša od 43 %. Otpornost na trošenje je izračunata je iz energije potrošene da bi se otklonila jedna jedinica metala s površine.
Fourteen low molecular mass UV absorbing ampholytes containing 1 or 2 weakly acidic and 1 or 2 weakly basic functional groups that best satisfy Rilbe's requirement for being good carrier ampholytes ...(ΔpK
= pKa
- pKa
< 2) were selected from a large group of commercially readily available ampholytes in a computational study using two software packages (ChemSketch and SPARC). Their electrophoretic mobilities were measured in 10 mM ionic strength BGEs covering the 2 < pH < 12 range. Using our Debye-Hückel and Onsager-Fuoss laws-based new software, AnglerFish (freeware, https://echmet.natur.cuni.cz/software/download), the effective mobilities were recalculated to zero ionic strength from which the thermodynamic pK
values and limiting ionic mobilities of the ampholytes were directly calculated by Henderson-Hasselbalch equation-type nonlinear regression. The tabulated thermodynamic pK
values and limiting ionic mobilities of these ampholytes (pI markers) facilitate both the overall and the narrow-segment characterization of the pH gradients obtained in IEF in order to mitigate the errors of analyte ampholyte pI assignments caused by the usual (but rarely proven) assumption of pH gradient linearity. These thermodynamic pK
and limiting mobility values also enable the reality-based numeric simulation of the IEF process using, for example, Simul (freeware, https://echmet.natur.cuni.cz/software/download).
Fourteen low molecular mass UV absorbing ampholytes containing 1 or 2 weakly acidic and 1 or 2 weakly basic functional groups that best satisfy Rilbe's requirement for being good carrier ampholytes ...(ΔpKa = pKamonoanion ‒ pKamonocation < 2) were selected from a large group of commercially readily available ampholytes in a computational study using two software packages (ChemSketch and SPARC). Their electrophoretic mobilities were measured in 10 mM ionic strength BGEs covering the 2 < pH < 12 range. Using our Debye‐Hückel and Onsager‐Fuoss laws‐based new software, AnglerFish (freeware, https://echmet.natur.cuni.cz/software/download), the effective mobilities were recalculated to zero ionic strength from which the thermodynamic pKa values and limiting ionic mobilities of the ampholytes were directly calculated by Henderson‐Hasselbalch equation‐type nonlinear regression. The tabulated thermodynamic pKa values and limiting ionic mobilities of these ampholytes (pI markers) facilitate both the overall and the narrow‐segment characterization of the pH gradients obtained in IEF in order to mitigate the errors of analyte ampholyte pI assignments caused by the usual (but rarely proven) assumption of pH gradient linearity. These thermodynamic pKa and limiting mobility values also enable the reality‐based numeric simulation of the IEF process using, for example, Simul (freeware, https://echmet.natur.cuni.cz/software/download).
Thermodynamic acidity constants (acid or acid‐base dissociation constants, sometimes called also as ionization constants) and limiting ionic mobilities (both of them at defined temperature, usually ...25°C) are the fundamental physicochemical characteristics of a weak electrolyte, that is, weak acid or weak base or ampholyte. We introduce a novel method for determining the data of a weak electrolyte by the nonlinear regression of effective electrophoretic mobility versus buffer composition dependence when measured in a set of BGEs with various pH. To correct the experimental data for zero ionic strength we use the extended Debye‐Hückel model and Onsager‐Fuoss law with no simplifications. Contrary to contemporary approaches, the nonlinear regression is performed on limiting mobility data calculated by PeakMaster's correction engine, not on the raw experimental mobility data. Therefore, there is no requirement to perform all measurements at a constant ionic strength of the set of BGEs. We devised the computer program AnglerFish that performs the necessary calculations in a user‐friendly fashion. All thermodynamic pKa values and limiting electrophoretic mobilities for arbitrarily charged substances having any number of ionic forms are calculated by one fit. The user input consists of the buffer composition of the set of BGEs and experimentally measured effective mobilities of the inspected weak electrolyte.
The linear theory of electromigration, including the first‐order nonlinear approximation, is generalized to systems with any equilibria fast enough to be considered instantaneous in comparison with ...the timescale of peak movement. For example, this theory is practically applied in the electrokinetic chromatography (EKC) mode of the CZE. The model enables the calculation of positions and shapes of analyte and system peaks without restricting the number of selectors, the complexation stoichiometry, or simultaneous acid–base equilibria. The latest version of our PeakMaster software, PeakMaster 6—Next Generation, implements the theory in a user‐friendly way. It is a free and open‐source software that performs all calculations and shows the properties of the background electrolyte and the expected electropherogram within a few seconds. In this paper, we mathematically derive the model, discuss its applicability to EKC systems, and introduce the PeakMaster 6 software.
Abstract
Fourteen low molecular mass UV absorbing ampholytes containing 1 or 2 weakly acidic and 1 or 2 weakly basic functional groups that best satisfy Rilbe's requirement for being good carrier ...ampholytes (Δp
K
a
= p
K
a
monoanion
‒ p
K
a
monocation
< 2) were selected from a large group of commercially readily available ampholytes in a computational study using two software packages (ChemSketch and SPARC). Their electrophoretic mobilities were measured in 10 mM ionic strength BGEs covering the 2 < pH < 12 range. Using our Debye‐Hückel and Onsager‐Fuoss laws‐based new software, AnglerFish (freeware,
https://echmet.natur.cuni.cz/software/download
), the effective mobilities were recalculated to zero ionic strength from which the thermodynamic p
K
a
values and limiting ionic mobilities of the ampholytes were directly calculated by Henderson‐Hasselbalch equation‐type nonlinear regression. The tabulated thermodynamic p
K
a
values and limiting ionic mobilities of these ampholytes (p
I
markers) facilitate both the overall and the narrow‐segment characterization of the pH gradients obtained in IEF in order to mitigate the errors of analyte ampholyte p
I
assignments caused by the usual (but rarely proven) assumption of pH gradient linearity. These thermodynamic p
K
a
and limiting mobility values also enable the reality‐based numeric simulation of the IEF process using, for example, Simul (freeware,
https://echmet.natur.cuni.cz/software/download
).
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