Approaches for coupled numerical simulation of high frequency tube welding process

Welding processes and installations used nowadays are mainly developed on practical experience and analytical calculations. Nevertheless, high frequency induction tube welding is a very complex three-dimensional dynamic process, where the electromagnetic and thermal characteristics are distributed not only in space but in time as well. A more profound detailed investigation of the induction tube welding process can be only done by numerical modelling. Full and local three-dimensional transient numerical models of induction tube welding process with continuous movement of the welded tube have been developed and tested. Coupled electromagnetic and thermal analyses are carried out at each time step of simulation for correction of temperature dependent material properties. Voltage or current of the induction coil can be individually input into electromagnetic analysis at each time step. This approach allows simulating “quasi” steady-state and transient operation modes

Coupled numerical multiphysics simulation methods in induction surface hardening

Numerical simulation is a valuable tool to help investigate complex multiphysics problems of engineering and science. This also applies to inductive surface hardening with its coupled electromagnetic and temperature fields as well as the microstructure changes of the hardened material. In this field, numerical simulation is a well-established approach for effective process design. This is particularly true since an analytical approach usually fails because of the complexity of the problems. Also, experiments oftentimes are not leading to a solution in an acceptable period of time because of the big number of process parameters. Furthermore, numerical simulation can help to investigate effects that could not have been observed otherwise. An example is the Joule heat distribution within a heated work piece during inductive heating. However, the fields of application as well as the methods of numerical simulation have to keep pace with technological progress. Two examples of new applications and methods for numerical simulation in induction hardening are presented in this paper: A complex 3D model of a large bearing and a new approach for the numerical simulation of the martensite microstructure

Sustained high-level expression of human factor IX (hFIX) after liver-targeted delivery of recombinant adeno-associated virus encoding the hFIX gene in rhesus macaques

The feasibility, safety, and efficacy of liver-directed gene transfer was evaluated in 5 male macaques (aged 2.5 to 6.5 years) by using a recombinant adeno-associated viral (rAAV) vector (rAAV-2 CAGG-hFIX) that had previously mediated persistent therapeutic expression of human factor IX (hFIX; 6%-10% of physiologic levels) in murine models. A dose of 4 × 1012 vector genomes (vgs)/kg of body weight was administered through the hepatic artery or portal vein. Persistence of the rAAV vgs as circular monomers and dimers and high-molecular-weight concatamers was documented in liver tissue by Southern blot analysis for periods of up to 1 year. Vector particles were present in plasma, urine, or saliva for several days after infusion (as shown by polymerase chain reaction analysis), and the vgs were detected in spleen tissue at low copy numbers. An enzyme-linked immunosorption assay capable of detecting between 1% and 25% of normal levels of hFIX in rhesus plasma was developed by using hyperimmune serum from a rhesus monkey that had received an adenoviral vector encoding hFIX. Two macaques having 3 and 40 rAAV genome equivalents/cell, respectively, in liver tissue had 4% and 8% of normal physiologic plasma levels of hFIX, respectively. A level of hFIX that was 3% of normal levels was transiently detected in one other macaque, which had a genome copy number of 25 before abrogation by a neutralizing antibody (inhibitor) to hFIX. This nonhuman-primate model will be useful in further evaluation and development of rAAV vectors for gene therapy of hemophilia B. © 2002 by The American Society of Hematology

Значення передопераційного періоду у відновленні рухової функції колінного суглоба при артроскопічній реконструкції передньої хрестоподібної зв’язки

The question of the role of the preoperative period of physical rehabilitation in patients with damage to the anterior cruciate ligament of the knee. The analysis and synthesis of scientific and methodological information on the most typical dysfunctions of the musculoskeletal system in patients as a result of damage to the anterior cruciate ligament, as well as modern means and methods of recovery for injuries capsule and ligaments of the knee. Found that among the domestic and foreign authors there is no consensus on the duration of preoperative period relevant patients. The earliest use of means and methods of physical rehabilitation after anterior cruciate ligament injury can reduce symptoms of post-operative complications and improve motor recovery of damaged limbs.Рассмотрен вопрос о роли предоперационного периода физической реабилитации у пациентов с повреждением передней крестообразной связки коленного сустава. Проведен анализ и обобщение научно-методических данных по вопросам наиболее характерных нарушений функции опорно-двигательного аппарата у пациентов в результате повреждения передней крестообразной связки, а также современных средств и методов восстановления при травмах капсульно-связочного аппарата коленного сустава. Установлено, что среди отечественных и зарубежных авторов отсутствует единое мнение относительно продолжительности предоперационного периода профильных пациентов. Наиболее раннее применение средств и методов физической реабилитации после повреждения передней крестообразной связки способствует уменьшению проявлений послеоперационных осложнений и повышению эффективности восстановления двигательной функции поврежденной конечности.Розглянуто питання щодо ролі передопераційного періоду фізичної реабілітації у пацієнтів з пошкодженням передньої хрестоподібної зв’язки колінного суглоба. Проведено аналіз та узагальнення науково-методичних даних з питань найбільш характерних порушень функції опорно-рухового апарату в пацієнтів у результаті пошкодження передньої хрестоподібної зв’язки, а також сучасних засобів і методів відновлення при травмах капсульно-зв’язкового апарату колінного суглоба. Встановлено, що серед вітчизняних та зарубіжних авторів відсутня єдина думка щодо тривалості передопераційного періоду профільних пацієнтів. Найбільш раннє застосування засобів і методів фізичної реабілітації після ушкодження передньої хрестоподібної зв'язки сприяє зменшенню проявів післяопераційних ускладнень і підвищенню ефективності відновлення рухової функції пошкодженої кінцівки

FERROELECTRIC NANOCOMPOSITES WITH GOVERNED INTERFACE ON BASE OF MAGNETIC POROUS GLASSES

Two-phase (nonporous) magnetic alkali borosilicate glasses have been produced by induction melting. Their macroscopic properties and crystal structure have been studied and it is shown that in the silica skeleton there are the agglomerates of Fe3O4. These agglomerates are formed by monodomain nanoparticles of magnetite and demonstrate the superparamagnetic properties. After special thermal treatment (liquation process) and chemical etching the nanoporous matrices with random dendrite pore structure and magnetic properties have been produced. The channels (porous space) were filled by ferroelectric materials KH2PO4 (KDP), KH2PO4+(NH4)H2PO4 (KDP-ADP or KADP), and NaNO2 and the effect of applied magnetic fields on phase transitions in these nanocomposite have been studied. It has also been established that a restricted geometry changed essentially the phase diagram of KADP.