Laser nano-manufacturing – State of the art and challenges

This paper provides an overview of advances in laser based nano-manufacturing technologies including surface nano-structure manufacturing, production of nano materials (nanoparticles, nanotubes and nanowires) and 3D nano-structures manufacture through multiple layer additive techniques and nano-joining/forming. Examples of practical applications of laser manufactured nano-structures, materials and components are given. A discussion on the challenges and outlooks in laser nano-manufacturing is presented.     

热障涂层后处理技术研究进展

热障涂层是一种降低航空发动机热端部件表面温度、提高发动机推力和效率的热防护技术,但其服役于高温、高压、高交变应力等恶劣环境而易脱落失效.对热障涂层的后处理技术进行了阐述,论述了真空热处理、热等静压处理、激光重熔、激光上釉、激光熔覆等后处理技术的方法和原理,并对比了不同工艺的优缺点.最后,展望了激光表面改性技术的应用前景和未来发展趋势.     

Advancement in the thermodiffusion theory of anisotropic inhomogeneous shells

This article represents the latter advancement in the modeling of diffusion processes in deformable solids. Special attention is given to the development of models for thin-walled shells with both thermal and atomic types of diffusion. Based upon these models, a number of general theorems and principles (i.e., the D'Alembert principle, Hamilton principle, mass forces analogy, Clapeyron theorem, fundamental energy theorem, and reciprocity theorem) are formulated and proved. These theorems allow for developing efficient methods for the solution of relevant boundary-value problems for the shells of this kind.     

Fuzzy Directional (FD) Filter for impulsive noise reduction in colour video sequences

This paper presents a novel Fuzzy Directional (FD) Filter for suppression of impulsive noise in colour video sequences. The proposed approach consists in the estimation of fuzzy levels to detect movement and noise presence in the neighbourhood frames, permitting to preserve the edges, fine details and chromaticity characteristics in colour images and video sequences. The new framework has been justified applying commonly used objective criteria, such as, Peak Signal to Noise Ratio (PSNR), Mean Absolute Error (MAE) and Normalized Colour Difference (NCD), as well subjective perception by human viewer showing better performance in comparison with known methods presented in the literature.     

A concept of combined cooling,heating and power system utilising solar power and based on reversible solid oxide fuel cell and metal hydrides

In energy systems, multi-generation including co-generation and tri-generation has gained tremendous interest in the recent years as an effective way of waste heat recovery. Solid oxide fuel cells are efficient power plants that not only generate electricity with high energy efficiency but also produce high quality waste heat that can be further used for hot and chilled water production. In this work, we present a concept of combined cooling, heating and power (CCHP) energy system which uses solar power as a primary energy source and utilizes a reversible solid oxide fuel cell (R-SOFC) for producing hydrogen and generating electricity in the electrolyser (SOEC) and fuel cell (SOFC) modes, respectively. The system uses “high temperature” metal hydride (MH) for storage of both hydrogen and heat, as well as “low temperature” MH's for the additional heat management, including hot water supply, residential heating during winter time, or cooling/air conditioning during summer time.The work presents evaluation of energy balances of the system components, as well as heat-and-mass transfer modelling of MH beds in metal hydride hydrogen and heat storage system (MHHS; MgH₂), MH hydrogen compressor (MHHC; AB₅; A = La + Mm, BNi + Co + Al + Mn) and MH heat pump (MHHP; AB₂; A = Ti + Zr, BMn + Cr + Ni + Fe). A case study of a 3 kWe R-SOFC is analysed and discussed. The results showed that the energy efficiencies are 69.4 and 72.4% in electrolyser and fuel cell modes, respectively. The round-trip COP's of metal hydride heat management system (MHHC + MHHP) are close to 40% for both heating and cooling outputs. Moreover, the tri-generation leads to an improvement of 36% in round-trip energy efficiency as compared to that of a stand-alone R-SOFC.     

LaMg11 with a giant unit cell synthesized by hydrogen metallurgy: Crystal structure and hydrogenation behavior

We have successfully applied a hydrogen metallurgy synthesis to yield LaMg_12?x intermetallic at 500 °C. During a vacuum thermal desorption from the LaH₃–MgH₂ nanocomposite prepared by reactive ball milling in H₂, hydrogen desorption from the La dihydride occurred via a mechanism of cooperative phase transformation at temperatures being 400° lower than the desorption from pure LaH₂. The crystal structure of the intermetallic was determined by synchrotron X-ray diffraction (SR XRD). The orthorhombic LaMg_12?x has a giant unit cell, the volume of which exceeds 8000 Å³. In situ SR XRD studies showed the fine details of the hydrogen desorption process with several parallel and consecutive transformation steps.     

Experimental Evaluation of Food-Grade Semi-Refined Carrageenan Toxicity

The safety of food additives E407 and E407a has raised concerns in the scientific community. Thus, this study aims to assess the local and systemic toxic effects of the common food additive E407a in rats orally exposed to it for two weeks. Complex evaluations of the effects of semi-refined carrageenan (E407a) on rats upon oral exposure were performed. Local effects of E407a on the intestine were analyzed using routine histological stains and CD68 immunostaining. Furthermore, circulating levels of inflammatory markers were assessed. A fluorescent probe O1O (2- (2′-OH-phenyl)-5-phenyl-1,3-oxazole) was used for evaluating the state of leukocyte cell membranes. Cell death modes of leukocytes were analyzed by flow cytometry using Annexin V and 7-aminoactinomycin D staining. Oral administration of the common food additive E407a was found to be associated with altered small and large intestinal morphology, infiltration of the lamina propria in the small intestine with macrophages (CD68⁺ cells), high systemic levels of inflammation markers, and changes in the lipid order of the phospholipid bilayer in the cell membranes of leukocytes, alongside the activation of their apoptosis. Our findings suggest that oral exposure to E407a through rats results in the development of intestinal inflammation.     

Solvation effects on spectral and photophysical properties of phenalenone dyes in polyurethane polymers

Spectral and photophysical properties of several phenalenone dyes were investigated in the dependence on a type of the polyurethane polymer matrix. The increase in polarity of the solid-state medium was shown to shift absorption and luminescence spectra to the low energy side. Effects of the substituents in the phenalenone chromophore on a Stokes shift value were studied. Photophysical properties of phenalenones were found out to be significantly dependent on the polymerization method of polymer matrices. Considerable growth in photostability of organic dyes was observed when the dyes were bonded covalently with a polymer chain.