Ways to determine reliability in the operation of ship parts made by banding method

In the development of modern shipbuilding conditions and the repair of ship units, a special role is given to the use of basic structural elements consisting of technological parts. When performing these steps, it is important to analyze the properties of the materials from which the technological components of ship equipment are made. Testing should be close to the operating conditions of ship axles and shafts, namely cyclic loading, aggressive and adhesive environment. Therefore, a special factor is the technological control over the sequence of manufacture, selection of materials, surfacing technology. All these requirements can be analyzed and predicted using computer modulation. Investigations of the properties of the transition layers of the weld and the base metal and their effect on the number of load cycles in the tests are also key. All conditions will be met with the optimal selection of the chemical component Ni - Cr, which provide the required level of doping. The hardness of the materials is ensured by the presence of Mg in the metal. Also important are the heat treatment modes that provide the desired final structure of the material for machining and surfacing. For this part and its elements, the best properties in terms of operation in fine austenitic and pearlitic structures. During the operation of ship shafts and axles, the propagation of puncture loads is performed due to the occurrence of final stresses at low-cycle and multi-cycle loads and subsequent fatigue of the structural lattice. When considering the range of materials used in combined structures is very large and includes most welded steels. According to the combination of materials in one unit, it is advisable to distinguish two main groups of structures: with welded joints of steels of the same structural class, but different alloying, and with welded joints of steels of different structural classes. In this regard, the decision to obtain a balanced bandage connection lies in obtaining a fine-grained structure of the weld metal and the seam area.

A 3D structural affinity model for multi-epitope in silico germinal center simulations

Vaccine development for mutating pathogens is challenged by their fast evolution, the complexity of immunodominance, and the heterogeneous immune history of individuals. Mathematical models are critical for predicting successful vaccine conditions or designing potent antibodies. Existing models are limited by their abstract and poorly structural representations of antigen epitopes. Here, we propose a structural lattice-based model for antibody–antigen affinity. An efficient algorithm is given that predicts the best binding structure of an antibody’s amino acid sequence around an antigen with shortened computational time. This structural representation contains key physiological properties, such as affinity jumps and cross-reactivity, and successfully reflects the topology of antigen epitopes, such as pockets and shielded residues. It is suitable for large simulations of affinity maturation. We perform in silico immunizations via germinal center simulations and show that our model can explain complex phenomena like recognition of the same epitope by unrelated clones. We show that the use of cocktails of similar epitopes promotes the development of cross-reactive antibodies. This model opens a new avenue for optimizing multivalent vaccines with combined antigen cocktails or sequential immunizations, and to reveal reasons for vaccine success or failure on a structural basis.

UV Photodetector Based on Mg-Doped GaN Thin Films Prepared by Sol-Gel Spin Coating

In this work, sol-gel spin coated of magnesium (Mg) doped gallium nitride (GaN) thin films grown on AlN sapphire substrate was reported. The structural, lattice vibrational, and electrical properties of the deposited films were investigated and compared. X-ray diffraction results show that the deposited films composed of wurtzite structure with preferred orientation of GaN(002). The Raman active phonon modes correspond to the E2(high) and A1(LO) at 568 cm-1 and 733 cm-1 phonon modes of the hexagonal GaN were observed, while a broad peak attributed to the Mg-related lattice vibrational mode was detected at 669 cm-1. The Raman phonon modes were detected by using Raman spectroscopy. Hall effects results show that the resistivity, carrier concentration, and hall mobility of the Mg-doped GaN film was 0.1397 Ω cm, 1.77 × 1018 cm3, and 6.04 cm2/Vs, respectively. Besides, the characteristics of the ultraviolet (UV) photoresponse of the fabricated detector were investigated. The current-voltage characteristics of the Mg-doped GaN UV photodetector exhibits Schottky behaviour. The current-voltage measurements were carried out at room temperature with a computer-controlled integrated Source Meter (Keithley 2400). Lastly, the ideality factor and Schottky barrier heights were calculated using thermionic emission theory.