Frequency dependences of higher-order constants of piezoelectric ceramics

The properties of TBC-3 and PZT-23 piezoelectric ceramics have been studied by the method of loaded three-element complex oscillator. Changes in the higher-order (up to fifth) parameters are considered for large mechanical (0–120 MPa) and electric (0–600 kV/m) loads. Results of studying the longitudinal flexibility s ₁₁ ^E , piezoelectric modulus d ₃₁, and dielectric permittivity ε ₃₃ ^σ are presented within a frequency range of 20–200 kHz, where the frequency dispersion of dielectric as well as piezoelectric and elastic parameters is observed.     

Experience in the health promotion of children in opisthorchiasis foci

The analysis covers 2555 appendectomies, performed on an emergency and scheduled surgery basis in the clinic of emergency surgery.--State University Hospital "Queen Giovanna", Sofia, over the period 1985-1997. Relaparotomy is necessitated in 28 cases (1.09 per cent) because of various postoperative complications. Data are presented on the number of relaparotomies, done under conditions of emergency and scheduled surgery, and with a special reference to the pathoanatomical character of appendicitis. The underlying causes of undertaking relaparotomy and postoperative lethality are analyzed. As shown by the obtained results post-relaparotomy mortality rate is the highest after primary operation for destructive form of appendicitis and advanced form of peritonitis.     

Service of refractories in a double bath steel melting furnace

Conclusions The absence of regenerators, the small quantity of easily removable powdery slag in the slaggers, the low wear of the head structure, the verticals, and the lower structure of the furnace substantially simplify repair operations.The much simpler construction of the furnace, compared with that of an open-hearth furnace, enables us to eliminate cumbersome switching systems; the entire switching system consists of two gate valves. The design of the furnace guarantees the use of industrial repair methods.The specific consumption of refractories and fuel for a double bath furnace are less than for the openhearth furnace, but the oxygen consumption is higher, and the output of acceptable metal less.Translated from Ogneupory, No.6, pp. 25–29, June, 1968.     

Hydrodynamics and Heat Transfer during Boiling in a Rotating Gas–Liquid Layer

Theoretical Foundations of Chemical Engineering - Research results regarding hydrodynamics and heat transfer during boiling in a rotating gas–liquid layer are presented. The dependencies for...     

Rheological Properties and Characteristics of Hydraulic Transportation and Heat-Mass Exchange of Coal-Water Fuels

The procedure is proposed for calculating the characteristics of flow and heat exchange of coal-water fuels as applied to the pipeline hydraulic transport and heat-mass exchange in the apparatus of ecologically clean combustion in the objects of power engineering.     

Complex Transposon Insertion as a Novel Cause of Pompe Disease

Pompe disease (OMIM#232300) is an autosomal recessive lysosomal storage disorder caused by mutations in the GAA gene. According to public mutation databases, more than 679 pathogenic variants have been described in GAA, none of which are associated with mobile genetic elements. In this article, we report a novel molecular genetic cause of Pompe disease, which could be hardly detected using routine molecular genetic analysis. Whole genome sequencing followed by comprehensive functional analysis allowed us to discover and characterize a complex mobile genetic element insertion deep in the intron 15 of the GAA gene in a patient with infantile onset Pompe disease.     

Monitoring the deformability of laminar foundation beds during their engineering preparation

This paper outlines practical experience gained with the development and use of monitoring of the consolidation compaction of nonuniform peaty foundation beds by vertical drainage with a surcharge at the experimental testing ground “Ol’gino” in a suburb of Saint Petersburg, which makes it possible to establish the effectiveness of the engineering preparation of laminar foundation beds. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 21–24, September–October, 1999.     

Self-mixing detection of backscattered radiation in single-mode pulse-periodic CO2 lasers

The self-mixing (autodyne) effect in single-mode CO(2) lasers with pulse-periodic (PP) pumping of the active medium is theoretically analyzed and experimentally investigated. A semiempirical model of the autodyne effect in CO(2) lasers of this type is developed that allows the laser beat signal to be described from the known shape of the generated pulses. The self-mixing effect in PP CO(2) lasers is shown to be identical with that in continuous-wave CO(2) lasers, except that the autodyne amplification during the laser pulse proves time-dependent. It is demonstrated that the amplitude-frequency characteristic of the autodyne amplification for PP CO(2) lasers is also of resonance nature, but its bandwidth is broadened, as compared with that in the case of continuous laser pumping. As in the case of continuous pumping, the self-mixing effect in PP CO(2) lasers can be used to detect and analyze backscattered signals, specifically for measuring the rates of destruction of materials by the 10 μm radiation and for monitoring this process.     

Self-assembled iron oxide nanoparticle multilayer: x-ray and polarized neutron reflectivity

We have investigated the structure and magnetism of self-assembled, 20 nm diameter iron oxide nanoparticles covered by an oleic acid shell for scrutinizing their structural and magnetic correlations. The nanoparticles were spin-coated on an Si substrate as a single monolayer and as a stack of 5 ML forming a multilayer. X-ray scattering (reflectivity and grazing incidence small-angle scattering) confirms high in-plane hexagonal correlation and a good layering property of the nanoparticles. Using polarized neutron reflectivity we have also determined the long range magnetic correlations parallel and perpendicular to the layers in addition to the structural ones. In a field of 5 kOe we determine a magnetization value of about 80% of the saturation value. At remanence the global magnetization is close to zero. However, polarized neutron reflectivity reveals the existence of regions in which magnetic moments of nanoparticles are well aligned, while losing order over longer distances. These findings confirm that in the nanoparticle assembly the magnetic dipole-dipole interaction is rather strong, dominating the collective magnetic properties at room temperature.     

Determination of heat transfer coefficients during solidification of a casting in a jet crystallizer

The problem of determining heat transfer coefficients in thermal processes described by nonlinear initial boundary-value problems for heat conduction equations in a cylindrical coordinate system is considered subject to axial symmetry. An algorithm is suggested and program means are created for identifying heat transfer coefficients. A computational experiment on determining heat transfer coefficients for the AK12 alloy is carried out, and recommendations for selecting numerical calculation parameters have been developed.