Self-piercing riveting for aluminium alloys-composites hybrid joints

In the paper, the growing interest on hybrid joints developed between composite panels and aluminium alloys blanks is focused. The self-piercing riveting operation is considered and its feasibility for the proposed joints verified. The most relevant process parameters were investigated in order to determine a suitable process window and, what is more, the mechanical performances of the developed joints were investigated in order to determine process parameters aimed to maximise them. Finally, the failure mechanics of the obtained joints were considered in order to highlight the mechanisms which occur and determine the lost of the load carrying capability of the joints. The developed experiments demonstrated that self-piercing riveting can be effectively used to join fibreglass composite panels and aluminium blanks.     

The canonical processes of a dramatized approach to information presentation

This paper describes the application “Carletto the spider” in terms of the mapping with the canonical processes of media production. “Carletto the spider” is a character-based guide to a historical site and implements the Dramatour approach for the design of drama-based interactive presentations. Dramatization makes presentations more engaging, thus improving the reception of the content by the user. The major technical issue of the approach is the segmentation of the presentation into audiovisual units that are edited on-the-fly in a way that guarantees dramatic continuity while adapting to the user response. We describe the workflow of the application and its mapping to the canonical processes of media production, envisaging possible standardizations for the application portability.     

Synthesis of Yb nanoparticles by laser ablation of ytterbium target in sodium bis(2-ethylhexyl)sulfosuccinate reverse micellar solution

Surfactant-coated ytterbium nanoparticles were produced by Nd:YAG laser ablation of a Yb bulk target immersed in sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/n-heptane micellar solution. In our experimental conditions, as highlighted by IR spectroscopy, AOT molecules are not decomposed by the intense laser pulses but play a pivotal role in the stabilisation of Yb nanoparticles. The formation of Yb nanoparticles in the liquid phase was monitored by UV-Vis spectroscopy whereas the Yb/AOT composites obtained by evaporation of the organic solvent were characterised by XPS and TEM. Data analysis consistently shows the presence of surfactant-coated, nearly spherical and non-interacting Yb nanoparticles of mean diameter of 3 nm.Moreover, the presence of bigger polycrystalline nanoparticles (about 30%) in coexistence with smaller mono crystalline ones indicates that, after the rapid formation of the pristine Yb nanoparticles from plume condensation, two processes effectively compete for their size distribution: nanoparticle agglomeration and surfactant adsorption.     

Dielectric properties of two phases of crystalline lutetium oxide

High-dielectric constant oxides are the focus of intense current research. As a contribution to the rationalization of the search for candidate materials, we compare the dielectric properties obtained from first-principles linear-response calculations for two phases—the ground state bixbyite and the competing hexagonal structures—of the crystalline oxide Lu₂O₃. The dielectric constants of bixbyite is about 12 and that of hexagonal is about 19 (the electronic constant being about 4.5 in both cases). This difference is due almost exclusively to the vibrational properties, with minor or no influence of charge anomaly differences; as these are related mainly to oxygen vibrations, we argue that the dielectric properties of sesquioxides will be determined mostly by their preferred structure, i.e. they will be poorer for bixbyite (e.g. Y₂O₃) than for hexagonal (e.g. La₂O₃) sesquioxides.     

Indentation Determination of Fatigue Limits in Silicate Glasses

An experimental approach has been used to measure the threshold stress intensity factor ( K _th) for subcritical crack growth in brittle materials using indentation cracks. The data show that K _th values existed in soda-lime-silica and soda-alumina-silica glasses that were tested in a neutral aqueous environment. For the former glass, tests also were performed in acidic and basic solutions. A threshold for subcritical crack growth was observed for acidic conditions but not for alkaline conditions.     

Sandwiched-Beam Procedure for Precracking Brittle Materials

A technique for precracking brittle materials is presented. This procedure, which is called the sandwiched-beam (SB) technique, allows the production of sharp through-thickness cracks with predetermined length in specimens with a rectangular section. A bar, in which an initial notch is produced by using a conventional saw, is inserted between two supporting beams and the sandwich assembly is loaded in three-point bending. Conditions can be defined that allow the stable propagation of a sharp flaw from the notch as the applied load is increased. Then, the cracked bar can be used to determine the fracture toughness. The SB technique is applied to different brittle materials, including soda-lime-silica glass, alumina, Si₃N₄, a SiC _w -Si₃N₄ composite, graphite, a Ti-Al intermetallic, and Carrara marble.     

基于古村落宅间元素模式的村落景观 设计优化策略——以徽州地区为例

新村空间设计语汇模块化是村落景观设计较为普遍的现象,也是地域特征弱化和空间不契合空间行为等问题的主要原因之一。古村落宅间元素是村民日常生活与村落环境在相互影响下长期适应性发展的结果,宅间元素模式研究可促进丰富新村空间设计语汇。以徽州地区古村落为例,从宅间元素的分类、图示、与空间行为的关联3个方面论述了古村落宅间元素模式研究方法论。通过徽州茆田新村景观设计阐述了宅间元素模式的应用,论述了基于古村落宅间元素模式的村落景观设计优化策略,有益于形成并推广地方空间设计语汇,避免过度依赖和使用既有的、来自城市的广场、草坪、树池等元素造成的全国村落的无差别设计。     

Catalysts for the Ethoxylation of Esters

The intermediates for the production of nonionic surfactants can be derived from petrochemicals and/or from renewable raw materials. In both, the role of catalysis is fundamental. In this paper the main results reported in the literature related with the catalysis for ethoxylation of fatty esters will be reviewed. The main open challenges for these technologies will be outlined.     

Oncogenic MicroRNAs Characterization in Clear Cell Renal Cell Carcinoma

A key challenge for the improvement of clear cell renal cell carcinoma (ccRCC) management could derive from a deeper characterization of the biology of these neoplasms that could greatly improve the diagnosis, prognosis and treatment choice. The aim of this study was to identify specific miRNAs that are deregulated in tumor vs. normal kidney tissues and that could impact on the biology of ccRCC. To this end we selected four miRNAs (miR-21-5p, miR-210-3p, miR-185-5p and miR-221-3p) and their expression has been evaluated in a retrospective cohort of formalin-fixed paraffin-embedded (FFPE) tissues from 20 ccRCC patients who underwent surgical nephrectomy resection. miR-21-5p and miR-210-3p resulted the most significantly up-regulated miRNAs in this patient cohort, highlighting these onco-miRNAs as possible relevant players involved in ccRCC tumorigenesis. Thus, this study reports the identification of specific oncogenic miRNAs that are altered in ccRCC tissues and suggests that they might be useful biomarkers in ccRCC management.     

可持续理念下的风景园林评价体系研究

随着可持续理念在20多年的发展中被广泛接受和认可,城市风景园林的可持续性也受到广泛关注,各国都在探索可持续理念下的城市景观的建设与发展。对不同国家和中国台湾地区现阶段已经建立的可持续风景园林的评价体系,按照定性、定量及综合评价方法的方式进行分类,分别进行阐述与比较,并提出了中国建立可持续风景园林评价体系的建议。