Monitoring of a pharmaceutical nanomilling process using grating light reflection spectroscopy

An optical diagnostic method, grating light reflection spectroscopy (GLRS), has been demonstrated for the in situ monitoring of properties of heterogeneous matrices in industrial processes. The technique is based on measurements near the critical points of intensity and phase in waves reflected from a transmission diffraction grating in contact with a diagnostic sample. The features contained in the reflection spectrum near these thresholds allow for the simultaneous determination of the real and imaginary parts of the dielectric function of the sample. Using these data, the milling progress of highly concentrated fluid suspensions is observed as the material is milled from approximately 40 mm to 160 nm in diameter. A theoretical model that closely resembles experimentally determined spectra was constructed and applied in combination with principal components analysis (PCA) to demonstrate that GLRS can be used to closely monitor changes in the mean particle size of the nanomilled drug product.     

Controlled growth of Co nanofilms on Si(100) by ion-beam deposition

This paper examines the effect of ion-beam sputtering conditions on the nucleation of Co nanofilms on Si(100). The argon ion energy is shown to play a key role in determining the sputtering process. Sputtering a cobalt target with argon ions less than 0.8 keV in energy produces granular layers. The cobalt layers grown at Ar⁺ ion energies above 1.2 keV are continuous even in the nucleation stage. The layers 1.2 to 2 nm in thickness have high resistivity and are comparable in magnetic properties to bulk material. The high-energy component of the total flux of cobalt atoms ejected from the target plays an important role in the initial stages of deposition, especially at argon ion energies from 1.2 to 2.2 keV. In the nucleation stage, the cobalt atoms have a finite penetration depth in the silicon substrate, where they give up energy which facilitates the formation of a continuous layer in the initial stage of the process.     

Measurements of Thermal Kinetic Characteristics of Film Structures

The features of the arrangement of a procedure of measuring thermal kinetic characteristics (specific heats of films and substrates, the substrate thermal conductivity, and the thermal resistance of the film–substrate and substrate–thermostat interfaces) of film structures using a computer are described. An amplifier circuit developed taking into account the technical and procedure requirements of the method is presented. The circuit includes a wide-band dc amplifier with a differential input and a linear amplitude–frequency characteristic in the range of 0 to 2 × 10⁶ Hz combined with a sample-and-hold circuit for controlling the dc component of a pulse signal.     

Tailored magnetic nanoparticles for direct and sensitive detection of biomolecules in biological samples

We developed nanoparticles with tailored magnetic properties for direct and sensitive detection of biomolecules in biological samples in a single step. Thermally blocked nanoparticles obtained by thermal hydrolysis, functionalized with specific ligands, are mixed with sample solutions, and the variation of the magnetic relaxation due to surface binding is used to detect the presence of biomolecules. The binding significantly increases the hydrodynamic volume of nanoparticles, thus changing their Brownian relaxation frequency which is measured by a specifically developed AC susceptometer. The system was tested for the presence of Brucella antibodies, a dangerous pathogen causing brucellosis with severe effects both on humans and animals, in serum samples from infected cows and the surface of the nanoparticles was functionalized with lipopolysaccharides (LPS) from Brucella abortus. The hydrodynamic volume of LPS-functionalized particles increased by 25-35% as a result of the binding of the antibodies, measured by changes in the susceptibility in an alternating magnetic field. The method has shown high sensitivity, with detection limit of 0.05 microg x mL(-1) of antibody in the biological samples without any pretreatment. This magnetic-based assay is very sensitive, cost-efficient, and versatile, giving a direct indication whether the animal is infected or not, making it suitable for point-of-care applications. The functionalization of tailored magnetic nanoparticles can be modified to suit numerous homogeneous assays for a wide range of applications.     

A computerized system for investigating friction processes in synovial joints

The work describes the set-up and operation of a computerized pendulum tribometer for investigating the tribological characteristics of synovial joints. The validity of the system is established for studies of friction in the cartilage-cartilage interface when the partitioned joint contains lubricating media of various (artificial or natural) origins.     

Growth of single-layer and multilayer Co/TiO<Subscript>2</Subscript> nanostructures with bulklike properties

We have studied the surface morphology, interfaces, and structure of individual Co and TiO₂ films 2 to 10 nm in thickness and those of Co/TiO₂ multilayers up to 100 nm in thickness. Auger depth profiling and transmission electron microscopy results show that [Co(2 nm)/TiO₂(2 nm)]₁₅, [Co(2 nm)/TiO₂(4 nm)]₁₅, and [Co(4 nm)/TiO₂(4 nm)]₁₂ structures are composed of continuous layers well adherent to one another, with sharp interfaces. The conclusion is made that such multilayer structures can be used as model systems in designing magneto-optical and spintronic devices.     

Controlled growth of Co nanofilms on Si(100) by ion-beam sputtering

The effect of process conditions on the properties of cobalt films grown on silicon by ion-beam sputtering is analyzed from the nucleation stage to film thicknesses corresponding to the properties of bulk material. The argon ion energy is shown to play a central role in determining the sputtering process. Sputtering a cobalt target with argon ions less than 0.8 keV in energy produces granular layers. The cobalt layers grown at argon ion energies above 1.2 keV are continuous even in the nucleation stage. The layers 1.2 to 2 nm in thickness have high resistivity and are comparable in magnetic properties to bulk material. The high-energy component of the total flux of cobalt atoms ejected from the target plays an important role in the initial stages of deposition, especially at argon ion energies from 1.2 to 2.2 keV. In the nucleation stage, the energy deposited by cobalt atoms in the silicon substrate facilitates the formation of a continuous layer in the initial stage of the process.     

Geometric and elastostatic calibration of robotic manipulator using partial pose measurements

The paper deals with the geometric and elastostatic calibration of robotic manipulator using partial pose measurements, which do not provide the end-effector orientation. The main attention is paid to the efficiency improvement of identification procedure. In contrast to previous works, the developed calibration technique is based on the direct measurements only. To improve the identification accuracy, it is proposed to use several reference points for each manipulator configuration. This allows avoiding the problem of non-homogeneity of the least-square objective, which arises in the classical identification technique with the full pose information (position and orientation). Its efficiency is confirmed by the comparison analysis, which deals with the accuracy evaluation of different identification strategies. The obtained theoretical results have been successfully applied to the geometric and elastostatic calibration of a serial industrial robot employed in a machining work cell for aerospace industry.