Periodic structure of spicular magnetic clusters in a magnetic liquid

The behavior of clusters formed by magnetic particles of magnetic liquid placed into a cylindrical capillary tube in magnetic field is described. Spicular clusters are formed from the sediment at the application of a magnetic field. They arrange themselves along the capillary repeating the direction of external magnetic field. Clusters distribute uniformly in the region of a magnetic field maximum. Such a state remains steady with respect to changes of the magnetic field gradient profile in definite limits. The structure of the uniformly ordered clusters is obtained experimentally. The capability of control of the structure period is shown. It is observed that increasing of magnetic field gradient up to the magnitude higher than a certain threshold value results in rearrangement of the clusters row into a multi-row hexagonal structure.     

Selecting the Coefficients of Sliding Friction in the Problem on Frictional Interaction of Three Solids

The choice of the coefficients of sliding friction in the static equilibrium problem for a system of three solids with friction at two points is discussed. This system simulates the mechanism of gravitational seismic isolation of a solid. It is shown that the coefficients of friction must be identical at both points of frictional contact irrespective of the type of the material and surface finish. A formula for the balanced coefficient of friction is derived based on experimental data     

Low Level Measurement of Plutonium Content in Bioassay Using SSNTD Alpha-Spectrometry

Solid state nuclear track detectors (SSNTD) find wide application in registration of different types of ionization irradiation due to excellent features: low cost, compactness, passivity and possibility of long term exposure for low activity measurements. One of the most shortcomings is in complex processing of the detector surface and following image analysis. However, present methods which allow reconstruction of track ranges and particle energies are intensively being developed. A developing trend in SSNTD alpha-spectrometry uses automated scanning microscope systems and specially designed mathematical software. Several parameters obtained from the analysis of etched tracks indi information about alpha-particle ranges in detector. The possibility to use some parameters (minor axis m and track end diameter d) for the spectrometry has been reported earlier. Intercomparison of SSNTD with semiconductor detectors (SCD) for ^238,239Pu content in bioassay within the interval 10^-3 to 1 Bq has been carried out. This comparison has demonstrated a good coincidence between these independent radiometric methods. A perspective of SSNTD use for spectrometric determination of low level activity is discussed. The background level playing a main role in low level detection has been also estimated. Influence of radon and thoron has been found as insignificant.     

Dynamic system of an engine with spatially rocking links: a mathematical model

A mathematical model of a diesel with swashplates is proposed. The results of studying its design, kinematics, and dynamics are presented. The kinematic chain of the statically determinate mechanism of the engine is schematized. The kinematic relations are obtained taking into account the presence of Hooke’s joints and swashplates. A mathematical model of the dynamic system of the engine is described. A numerical example is given. The kinematics and dynamic processes of the engine are studied     

Modeling mechanical systems of variable structure

Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 25, No. 6, pp. 81–88, June, 1989.     

Methanol Decomposition in a Water–Methanol Equimolar Mixture on a Nickel-Promoted Copper–Zinc–Cement Catalyst

Methanol decomposition in a water–methanol equimolar mixture is studied in the presence of a nickel-promoted copper–zinc–cement catalyst. Methanol decomposition at 200–300°C on the oxide and reduced forms of the catalyst yields a gas with an H₂/CO ratio close to two. The use of an equimolar CH₃OH–H₂O mixture under analogous conditions enables obtaining gaseous products with a hydrogen concentration up to 75 vol %.     

Two‐step chromatography purification of IgGs possessing sialidase activity from human blood serum

Sialation of cell surface is known to be tightly connected with tumorigenicity, invasiveness, metastatic potential and clearance of aged cells, while sialation of immunoglobulin G (IgG) molecules determines their anti‐inflammatory properties. Recently, we have found for the first time IgG‐antibodies possessing sialidase‐like activity (sialylic abzyme) in blood serum of multiple myeloma and systemic lupus erythematosis patients. This abzyme was detected in a pool of IgGs purified by a typical procedure including immunoglobulin's precipitation with ammonium sulfate and following chromatography on protein G–Sepharose column. Here we describe a novel matrix for affinity purification of sialylic abzyme that is based on using bovine submandibular gland mucin conjugated to Sepharose matrix (mucin–Sepharose). This matrix preferentially binds sialidase‐like IgGs from a pool of sialidase‐active fraction of proteins precipitated with 50% ammonium sulfate from blood serum of the systemic lupus erythematosis patients. That allowed us to develop a new scheme of double‐step chromatography purification of sialidase‐like IgGs from human blood serum. Copyright © 2014 John Wiley & Sons, Ltd.     

Product design based on discrete particle modeling of a fluidized bed granulator

Fluidized bed agglomeration is a process commonly used to construct powdered food or pharmaceuti cal products to improve their instant properties. This works analyzes the influence of a wide range of operating parameters （i.e., fluidization air flow rate, temperature, and liquid injection rate） on growth rate, process stability, and product particle structure. Different granulator configurations （i.e., top spray, Wurster coater, spouted bed） are compared using identical process parameters. The impacts of both pro cess variables and granulator geometry on the fluidization regime, the particle and collision dynamics, and the resulting product structure and corresponding properties are studied in detailed simulations using a discrete particle model （DPM） and labscale agglomeration experiments with amorphous dextrose syrup （DE21）. The combination of numerical and experimental results allows to correlate the kinetics of micro scale particle interactions and the final product properties （i.e., agglomerate structure and strength）. In conclusion, detailed DPM simulations are proven as a valuable tool for knowledgebased product design.