Optimal conditions for determination of zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide in animal feed by micellar electrokinetic capillary chromatography

A separation technique for zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide in animal feedstuffs by micellar electrokinetic capillary chromatography (MEKC) was developed. The running buffer was 20 mmol l^-1 borate, 20 mmol l^-1 phosphate, pH 8.4, containing 20 mmol l^-1 sodium dodecylsulphate and 10% (v/v) methanol. MEKC was performed at 25°C; the applied voltage was 25 kV with a running pressure of 10 mbar. Simultaneous UV detection for all analytes was at 215 nm. The method was validated for specificity, accuracy, linearity, precision and robustness. It was shown to be specific, accurate (recoveries were 99.7 ± 0.3, 99.9 ± 0.9, 99.8 ± 1.0 and 99.5 ± 0.4, respectively, for oxytetracycline-, sulfacetamide-, polymyxin B- and zinc bacitracin-spiked samples of feed for cow, pigs, chicken and cattle), linear over the tested range (correlation coefficients ≥0.9987) and precise (RSDs below 1.8% for each analyte). The method was applied to determine zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide as additives in animal feed.     

Effect of Common Cause Failures on Indirect Costs

Next generation bridge management systems will take into consideration multiple hazard scenarios and not only traffic loading and structural deterioration as they do now. The indirect costs used in these bridge management systems to determine optimal management strategies vary according to the hazard scenarios considered. The difference depends on whether or not the bridge failures are due to a common cause, such as a single flood or earthquake, or due to load events that may be considered statistically unrelated, such as truck loads. To illustrate the effect of common cause bridge failures on indirect costs, two examples are presented that treat the failures first as if they are due to statistically independent loading events and then as if they are due to a common cause. To examine the effect of bridge failures on indirect costs of the system, estimation is performed at the network level. The first example, on a simple network, shows the indirect cost estimate for all of the network condition states. The second example, on a complex network, shows the difference in the possible reduction of total indirect costs with a single bridge intervention as well as the change in intervention sequence. The main conclusions are that total indirect costs and optimal intervention sequences differ depending on whether or not bridge failures are due to a common cause, and that the largest changes in indirect cost estimation occur when simultaneously failed bridges affect the method of indirect cost incurrence.     

Forced vibrations of a rigid body on a three-parameter foundation

The dynamic characteristics of the foundation model proposed by Kerr¹ are studied in connexion with the problem of the forced vibrations of a rigid beam supported by an elastic medium of finite depth (the two-dimensional case). Smooth and permanent contact is considered. Damping is included by complex foundation parameters. A resonant effect concerning the bending moments in finite beams is pointed out. Frequency-response curves and contact-pressure distributions are given for both axi- and anti-symmetrical vibrations.     

The integration of strap-down INS and GPS based on adaptive error damping

The concept and results of integration of a strap-down inertial navigation system (INS) based on low-accuracy inertial sensors and the global positioning system (GPS) have been presented in this paper. This system is aimed for the purposes of navigation, automatic control, and remote tracking of land vehicles. The integration is made by the implementation of an extended Kalman filter (EKF) scheme for both the initial alignment and navigation phases. Traditional integration schemes (centralized and cascaded) are dominantly based on the usage of high-accuracy inertial sensors. The idea behind the suggested algorithm is to use low-accuracy inertial sensors and the GPS as the main source of navigation information, while the acceptable accuracy of INS is achieved by the proper damping of INS errors. The main advantage of integration consists in the availability of reliable navigation parameters during the intervals of absence of GPS data. The influence of INS error damping coefficients is different depending on the fact whether the moving object is maneuvering or is moving with a constant velocity at that time. It is proposed that INS error damping gain coefficients generally should take higher values always when GPS data are absent, while at the same time their values in the error model (EKF prediction phase) can be additionally adapted according to the actual values of vehicle acceleration. The analysis of integrated navigation system performances is made experimentally. The data are acquired along the real land vehicle’s trajectory while the intervals of absence of GPS data are introduced artificially on the parts characterized both by maneuver and by constant velocity.     

A low-cost inductive proximity sensor for industrial applications

In this paper, we present an inductive proximity sensor with fully integrated electronics. The sensor with the compact hybrid configuration is composed of a sensing flat coil and an integrated electronic interface. We focused during the development on the temperature stability and robustness of the sensor by keeping its low-fabrication cost. The sensor exhibits a longitudinal resolution of 120 nm for an aluminum target position up to 500 μm from the sensing coil with the side size of 3.5 mm. The temperature drift of the sensor is less than 700 ppm/°C for the same range of the target position. The total working range is from 100 to 1500 μm. The sensor power consumption is 100 mW and the active sensor dimensions are 3.5 mm×3.5 mm×1.2 mm. We also showed the facility of the sensor packaging. This kind of integrated sensor has the potential for even more industrial applications.     

Harmonization of color measurements for dental application

This multicenter study evaluated the effect of harmonizing spectrophotometric (d/8°) color measurements by using actual dental materials of clinically relevant thickness and translucency as “calibration tiles.” Ten tooth-colored, 1-mm thick, resin- and ceramic-based materials were tested at the coordinating center (CC) and six research sites (RS). Correction factors were calculated for each material and each site to obtain the corrected reflection spectra from the non-corrected data set. Non-corrected (_NC) and corrected (_C) reflection values were converted into CIEDE2000 and CIELAB color parameters for the following comparisons: CC vs RS_NC and CC vs RS_C, between RS_NC vs RS_NC and RS_C vs RS_C pairs, and among RS separately (α = 0.05). Mean color differences for CC vs RS_NC and corresponding CC vs RS_C values were ΔE₀₀ = 4.2 (2.6) and ΔE₀₀ = 0.7 (0.6), respectively. Corresponding values for RS_NC vs RS_NC and RS_C vs RS_C specimen pairs were ΔE₀₀ = 5.9 (2.9) and ΔE₀₀ = 1.0 (0.5), respectively. The CIEDE2000 NC vs C comparison for each research site separately ranged from 0.5 to 8.5. Color differences of CC vs RS_C and RS_C vs RS_C pairs decreased 83% to 84.5% as compared with respective color differences for non-corrected research site measurements and was RS dependent (P < .001). The obtained results validated the proposed method of harmonizing color measurements for dental application as a reliable quality control tool for dental research laboratories and industry.     

A new meshless “fragile points method” and a local variational iteration method for general transient heat conduction in anisotropic nonhomogeneous media. Part I: Theory and implementation

Abstract

A new and effective computational approach is presented for analyzing transient heat conduction problems. The approach consists of a meshless Fragile Points Method (FPM) being utilized for spatial discretization, and a Local Variational Iteration (LVI) scheme for time discretization. Anisotropy and nonhomogeneity do not give rise to any difficulties in the present implementation. The meshless FPM is based on a Galerkin weak-form formulation and thus leads to symmetric matrices. Local, very simple, polynomial and discontinuous trial and test functions are employed. In the meshless FPM, Interior Penalty Numerical Fluxes are introduced to ensure the consistency of the method. The LVIM in the time domain is a combination of the Variational Iteration Method (VIM) and a collocation method in each finitely large time interval. The present methodology represents a considerable improvement to the current state of science in computational transient heat conduction in anisotropic nonhomogeneous media. In this first part of the two-paper series, we focus on the theoretical formulation and implementation of the proposed methodology. Numerical results and validation are then presented in Part II.     

Optimal conditions for determination of zinc bacitracin,polymyxin B,oxytetracycline and sulfacetamide in animal feed by micellar electrokinetic capillary chromatography

A separation technique for zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide in animal feedstuffs by micellar electrokinetic capillary chromatography (MEKC) was developed. The running buffer was 20 mmol l^?1 borate, 20 mmol l^?1 phosphate, pH 8.4, containing 20 mmol l^?1 sodium dodecylsulphate and 10% (v/v) methanol. MEKC was performed at 25°C; the applied voltage was 25 kV with a running pressure of 10 mbar. Simultaneous UV detection for all analytes was at 215 nm. The method was validated for specificity, accuracy, linearity, precision and robustness. It was shown to be specific, accurate (recoveries were 99.7?±?0.3, 99.9?±?0.9, 99.8?±?1.0 and 99.5?±?0.4, respectively, for oxytetracycline-, sulfacetamide-, polymyxin B- and zinc bacitracin-spiked samples of feed for cow, pigs, chicken and cattle), linear over the tested range (correlation coefficients ≥0.9987) and precise (RSDs below 1.8% for each analyte). The method was applied to determine zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide as additives in animal feed.     

Feasibility study of SiC-ceramics as a potential material for bone implants

In this paper, we discuss silicon carbide (SiC) ceramics as potential materials for biomedical applications. SiC samples were prepared without addition of undesired elements that might have adverse health effect and were characterized with respect to mechanical and magnetic properties, bioactivity, wetting behavior, and release of ions. The materials characteristics are compared to those for Ti6Al4V alloy. Among the examined ceramics, SiC with MgO as sintering aid met the expectation to the greatest extent. Elastic modulus of the material with 24 % porosity is 80 GPa, flexural strength 180 MPa, and fracture toughness ~3 MPa m^1/2. The material shows good wetting properties and is weakly diamagnetic. On the other hand, bioactivity estimated on the basis of hydroxyapatite formation in simulated body fluid is only achieved by surface modification. Thus, although SiC ceramics show potential for use in biomedical applications, it should be further developed to meet the requirements.     

Modified quadratic loss function for a trivariate response with the exact feasible region for parameters

This paper deals with modification of Taguchi's quadratic quality loss function (QQLF) for a trivariate responses, each having a NtB (nominal-the-best) type quality characteristic and correlated in pairs. It tends to improve and extend results obtained in 0025 and 0035. Impossibility to solve nonlinear constraint in [6] resulted in an approximate algorithm to determine unknown parameters of QQLF. Here the nonlinear constraint is solved analytically and consequently the exact feasible region is obtained. The QQLF is formed by means of the parameters from the restrictive feasible region and proved suitable for all the types of correlation among quality characteristics.