The difference between Newtonian and relativistic forces

This paper discusses a new turn in the 148-year old electrodynamic force law controversy between the 1822 Ampère force law of the Newtonian electrodynamics and Grassmann's 1845 law which has become the electrodynamic force law of relativistic electromagnetism. Faced with the infallibility of Ampère's empirical law, defenders of relativity theory now argue that Ampère's law is equivalent to the relativistic law. This paper demonstrates that, far from being equivalent, the laws require two different mechanics of solid bodies, disagree on internally generated stresses, and predict different force distributions.     

Transient flow towards a well in an aquifer including the effect of fluid inertia

Transient propagation of weak pressure perturbations in a homogeneous, isotropic, fluid saturated aquifer has been studied. A damped wave equation for the pressure in the aquifer is derived using the macroscopic, volume averaged, mass conservation and momentum equations. The equation is applied to the case of a well in a closed aquifer and analytical solutions are obtained to two different flow cases. It is shown that the radius of influence propagates with a finite velocity. The results show that the effect of fluid inertia could be of importance where transient flow in porous media is studied.List of symbols b Thickness of the aquifer, m - c ₀ Wave velocity, m/s - k Permeability of the porous medium, m² - n Porosity of the porous medium - p( ,t) Pressure, N/m² - Q Volume flux, m³/s - r Radial coordinate, m - r _w Radius of the well, m - s Transform variable - S Storativity of the aquifer - S _d(r, t) Drawdown, m - t Time, s - T Transmissivity of the aquifer, m²/s - ( ,t) Velocity of the fluid, m/s - Coordinate vector, m - z Vertical coordinate, m - Coefficient of compressibility, m²/N - Coefficient of fluid compressibility, m²/N - Relaxation time, s - (r, t) Hydraulic potential, m - Dynamic viscosity of the fluid, Ns/m² - Dimensionless radius - Density of the fluid, Ns²/m⁴ - (, ) Dimensionless drawdown - Dimensionless time - , x Dummy variables - ₀, ₁ Auxilary functions     

The Kissinger law and isokinetic effect: Part II. Experimental analysis

On the basis of copper sulphate pentahydrate thermal dissociation, for analyzed reactions I to IV, 6 thermokinetic equations was discussed. Arrhenius law parameters were determined and the isokinetic effect (IE) and Kissinger law appearing was analyzed. It was found that only dependence resulting from isokinetic effect, in the form k _m=q/T _m, relates to the suitable thermokinetic Eq. (2) and Kissinger law in modified form (14). The confirmation was made that the possibility of determining the averaged activation energy from thermokinetic equations using suitable correction coefficients exists.This revised version was published online in November 2005 with corrections to the Cover Date.     

Effects of substituted ligands on the mobility of complexed anions

From conductance and viscosities measurements on Pr₄NCl, Et₄NBr, and AgNO₃ in acetonitrile and Et₃NBr in nitrobenzene, the Walden products of the anion at infinite dilution were determined in presence of various concentrations of substituted benzoic acids. From these data it was possible to compute the values of the Walden products of the once complexed anions and to estimate the order of magnitude of the Walden products of twice complexed anions. Stokes' law is not obeyed, and the Walden products are not proportional to the third root of the molar volume of the complexed ions, as a consequence of their lack of sphericity. The assumption that the drag force which acts on the ions is proportional to the volume of the substituents results in a linear expression between the reciprocals of the Walden products and the molar volume of the ligands. The experimental results fit this expression within the limits of the experimental errors, and the slopes of the lines are nearly the same for all the anions and for the two solvents studied here, namely, 2.5×10^–4 ohm-cm^–5 mole-cP^–1.     

Low detection limit spectrophotometry

An efficient, more sensitive and accurate spectrophotometric process is possible and can be used to obtain qualitative or quantitative results for analytes at limiting concentrations lower than usual. Transmission measurements (incident light power, P₀, or transmitted, P) are performed with a fluorescence spectrometer. One cell only is used to measure standards or unknown solutions, placed between the standard holder cuvette and the emission monochromator of the instrument. The source of the radiant power (P₀) is not the xenon lamp but the fluorescence or scattered radiation from the holder cuvette filled with an appropriate solution. The analyte concentration is found from a calibration graph, based upon Beer’s law or the approximate formula P₀−P=2.303P₀εbc, which is valid for dilute solutions. Determination of iron in a reference material, using 1,10-phenanthroline as the chromogenic reagent, was chosen as an example to demonstrate the suitability of the proposed method and clarify several important statistical questions. Also discussed is why and to what extent molecular fluorescence methods are more sensitive than molecular absorption methods.     

Measurement of rheological properties of corn stover suspensions

Corn stover is currently being evaluated as a feedstock for ethanol production. The corn stover suspensions fed to reactors typically range between 10 and 40% solids. To simulate and design bioreactors for processing highly loaded corn stover suspensions, the rheologic properties of the suspension must be measured. In systems with suspended solids, rheologic measurements are difficult to perform owing to settling in the measurement devices. In this study, viscosities of corn stover suspensions were measured using a helical ribbon impeller viscometer. A calibration procedure is required for the impeller method in order to obtain the shear rate constant, k, which is dependent on the geometry of the measurement system. The corn stover suspensions are described using a power law flow model.     

金纳米微粒与盐酸氯丙嗪相互作用的共振Rayleigh散射光谱研究及其分析应用

在pH 1.8~3.3的酸性介质中,金纳米微粒本身有一定的共振瑞利散射(RRS)强度,但盐酸氯丙嗪本身的RRS强度十分微弱,当二者共存时,溶液的RRS强度显著增强并出现新的RRS光谱,在280~368 nm之间产生强烈的散射带,其最大散射波长位于368 nm,并在284、440、498 nm处有明显的散射峰。在一定条件下,盐酸氯丙嗪在0~0.08 mg/L范围内与ΔIRRS强度成正比,方法具有较高的灵敏度,对盐酸氯丙嗪的检出限(3σ)达到1.75μg/L。本文考察了反应体系的RRS光谱特征,研究了适宜的反应条件、影响因素及分析化学性质,研究了共存物质的影响,表明方法具有较好的选择性,据此发展了一种用金纳米微粒作RRS探针测定盐酸氯丙嗪的新方法。     

Cathode of a fuel cell with a solid polymer electrolyte: Calculating overall currents in the presence of a gas-diffusion layer

Mathematical apparatus, which makes it possible to perform calculations of the current-voltage characteristics of cathodes of fuel cells with a solid polymer electrolyte in conditions where there are present extraneous diffusion restrictions is proposed. In so doing, the partial pressure of oxygen and the absolute pressure of gas in the gas chamber may assume any values. First of all presented are the results of calculations of the current-voltage characteristics intrinsic to active layers of the air and oxygen cathodes, which are performed under the assumption that the extraneous diffusion restrictions are absent altogether. Thereafter, in the same conditions (at the same parameters that characterize the active layer of a cathode), obtained are results of a calculation of the current-voltage characteristics inherent in the air and oxygen cathodes in the presence of extraneous diffusion restrictions. Afterward there is performed an analysis of the way a gas-diffusion layer restricts the process of generation of current in a cathode and of what measures should be taken in order for the extraneous diffusion restrictions to become less significant.     

Study on the interaction of trypsin with some DNAs and their analytical application by resonance Rayleigh scattering spectra

When trypsin reacts with Herring sperm DNA (hsDNA), Salmon sperm DNA (sDNA), and Calf thymus DNA (ctDNA) to form a complex, the resonance Rayleigh scattering (RRS) was remarkably enhanced and new RRS spectra appear. These new spectra have similar characteristics of RRS spectra. The maximum RRS peaks are at 307 nm (hsDNA, sDNA) and 290 nm (ctDNA), and other peaks are at 350 nm. The scattering intensity is proportional to the concentration of DNA or trypsin; so this intereaction can be used to determine trypsin using DNA or DNA using trypsin. In the determination of DNA using trypsin, the linear ranges for hsDNA, sDNA, and ctDNA are 0–2.3, 0–2.5, and 0–1.9 μg·mL⁻¹, and the detection limits are 0.4, 0.7, and 1.1 ng·mL⁻¹, respectively. In the determination of trypsin using hsDNA, the linear range is 0–30.0 μg·mL⁻¹, and the detection limit is 39.0 ng·mL⁻¹. In this paper, the intereaction conditions were optimized. The affecting factors, chemical properties of the complex, and the composition ratio of trypsin with DNA were investigated. Using trypsin as RRS probe, a sensitive method for the determination of trace amounts of DNA was developed. Translated from Chemical Journal of Chinese Universities, 2006, 27(3) (in Chinese)     

Deviation from Ohm's law in electric field assisted capillary liquid chromatography

Earlier studies of electric field assisted LC (EF-LC) have shown that the effect on charged analytes of the application of an electric field over a capillary LC column is relatively small. Charged analytes can only be affected by the electric field while present in the mobile phase, which makes the effective time for influence of the electric field t(0) independent of retention time. Because the charged analytes only can be affected for a short time the electric field strength ought to be high in order to increase the impact of the electric field on the separation. We have, however, found that only a relatively low electric field strength can be used in EF-LC when pressure is used as main driving force. The useful field strength was limited by a dramatic increase in the current. This increase in current was found to origin from an increased concentration of buffer ions that have an electrophoretic mobility towards the pumped flow.