Analysis of Airworthiness Requirements on Amdt.25–132 of Limit of Validity to Preclude Widespread Fatigue Damage

AbstractThis article introduces innovatory changes and background to inspections of WFD for transport category aircraft which have resulted in the amendment 25-132 of limit of validity (LOV), also indicates a proactive approach which should be taken to address WFD before WFD occurs. With regard to the amendment to regulations on WFD issued by FAA, this article analyzes and interprets the actions of the design approval holder(DAH) and the related compliance methods, focusing on the applicability of the new regulations to WFD and on the methodologies and processes for performing aircraft WFD evaluations which include the determination of inspection start points(ISP) and structural modification points(SMP), the establishment of limits of validity (initial limits and extended limits), the establishment and revision of airworthiness limitations and Airworthiness Limitations section(ALS), the compliance for part 121 and 129 operators under new regulations, etc. Then a number of new research directions are presented in this article for domestic civil aircraft structure damage tolerance design and analysis for the present and the future

Influence of installation deviation on dynamic performance of synchronous magnetic coupling

To improve dynamic characteristics of synchronous magnetic coupling, this paper mainly analyzed the influence of the installation deviation on the synchronous magnetic coupling’s dynamic performance used in the horizontal axis wave energy power generation device. Dynamic characteristics equations based on Lagrange equation are built in the paper to analyze the dynamic characteristic of synchronous magnetic coupling. The radial deviation, the angle deviation and the center-of-mass deviation are considered in the equation. The influence of those installation deviations on the synchronous magnetic coupling performance is analyzed based on the mathematical model. The results show that the rise time, the overshoot, the peak time, the adjusting time and the oscillation of the synchronous magnetic coupling are almost not affected by those installation deviations

A new type flexible transmission mechanism used in ocean energy converters

Traditional contact seal is usually used in rotating parts of ocean energy converters. It is hard to avoid leakage, and with the increase of working time, the leakage becomes serious, which will make ocean energy converters fail to work. In the paper, a new type isolation transmission mechanism, which is permanent magnetic coupling, replaces the traditional contact seal and achieves absolute seal of the rotating parts and longtime operation of ocean energy converters. This paper introduces permanent magnetic coupling into ocean energy converters and uses the equivalent magnetic charge theory to analyze the influence of magnet pole-pairs number on the transmitted torque of permanent magnetic coupling. The relationship between permanent magnetic coupling transmitted torque and magnet pole-pairs number is obtained. The paper is conducive to the promotion of using permanent magnetic coupling in ocean energy converters

Research on Microstructure and Properties of Medium Carbon Steel Parts Manufactured by HDMR Technology

A new study on manufacturing medium carbon steel parts by HDMR (Hybrid Deposition and Micro Rolling) technology was carried out, and the microstructures and mechanical properties obtained by HDMR process and freeform arc deposition process respectively were tested and compared in this paper. The experiment results show that: compared with the freeform arc deposition process, the grain size number obtained by HDMR process increased from 3.0 to 9.0；the tensile strength and yield strength were increased by 37.1%, 68.6%，in contrast to the investment casting, increased by 65.4% and 107.7%; compared with the forging, the tensile strength and yield strength were increased by 12.9% and 31.4% respectively. Finally, a medium carbon 45 steel aeronautical part difficult to overlay was manufactured successfully by HDMR technology, thus a new efficient way for additive manufacturing of hard-shaping metal parts at high-quality with low-cost was provided.Mechanical Engineerin

High performance Bi2Te3 nanocomposites prepared by single-element-melt-spinning spark-plasma sintering

The last decade has witnessed nanocomposites becoming a new paradigm in the field of thermoelectric (TE) research. At its core is to prepare high performance TE nanocomposites, both p- and n-type, in a time and energy efficient way. To this end, we in this article summarize our recent effort and results on both p- and n-type Bi2Te3-based nanocomposites prepared by a unique single-element-melt-spinning spark-plasma sintering procedure. The results of transport measurements, scanning and transmission electronic microscopy, and small angle neutron scattering have proved essential in order to establish the correlation between the nanostructures and the TE performance of the materials. Interestingly, we find that in situ formed nanocrystals with coherent boundaries are the key nanostructures responsible for the significantly improved TE performance of p-type Bi2Te3 nanocomposites whereas similar nanostructures turn out to be less effective for n-type Bi2Te3 nanocomposites. We also discuss the alternative strategies to further improve the TE performance of n-type Bi2Te3 materials via nanostructuring processe

(5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetra­aza­cyclo­tetra­deca-4,11-diene)nickel(II) bis­[O,O′-bis­(4-tert-butyl­phen­yl) dithio­phosphate]

The title salt, [Ni(C16H32N4)](C20H26O2PS2)2, comprises a centrosymmetric [Ni(Me6[14]dieneN4)]2+ dication (Me6[14]dieneN4 is 5,7,7,12,14,14-hexa­methyl-1,4,8,11-tetra­aza­cyclo­tetra­deca-4,11-diene) and two O,O′-bis­(4-tert-butyl­phen­yl) dithio­phosphate anions. The NiII ion lies on an inversion centre and displays a slightly distorted NiN4 square-planar chelation arrangement with four N atoms from the Me6[14]dieneN4 macrocycle. Two S atoms from symmetry-related anions are located in pseudo-axial positions with respect to the NiII ion, with Ni⋯S distances of 3.2991 (7) Å. Inter­molecular N—H⋯S and C—H⋯S hydrogen bonds link the complex cation and pair of anions into a 1:2 type salt

LncRNA NBAT-1 inhibits the progression of hepatocellular carcinoma by interacting with CYLD

Purpose: To illustrate the biological influences of long non-coding RNA (lncRNA) NBAT-1 (neuroblastoma associated transcript 1) on HCC progression and the molecular mechanism of action. Methods: NBAT-1 levels in HCC tissues and cell lines were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between NBAT-1 and prognosis in HCC was analyzed. After knockdown of NBAT-1 in HepG2 and Hep3B cells, proliferative and migratory changes were assessed by cell counting kit-8 (CCK-8) and Transwell assay, respectively. The interaction between NBAT-1 and CYLD was confirmed by subcellular fraction determination and RNA binding protein immunoprecipitation (RIP). Rescue experiments were conducted to verify the involvement of CYLD in HCC cell functions regulated by NBAT-1. Results: NBAT-1 was downregulated in HCC tissues. Its level was much lower in metastatic or advanced stage HCC patients (p < 0.05), showing a certain prognostic potential. Knockdown of NBAT-1 stimulated proliferative and migratory potentials in HepG2 and Hep3B cells. NBAT-1 was mainly distributed in the cell cytoplasm. The mRNA and protein levels of CYLD were downregulated in HCC cells by NBAT-1 knockdown, displaying a positive interaction. CYLD was involved in the regulatory effect of NBAT-1 on HCC progression. Conclusion: Through a positive interaction with CYLD, NBAT-1 inhibits the malignant progression of HCC. These findings provide a potential approach to the development of targeted therapies for HCC