Search results for " Microstructure"

Numerical prediction of Biphasic Titanium Alloys Microstructure in Hot Forging Operations.

2012

Modern transportation industries shall comply with two demanding requirements: reducing operational consumption together with production costs coming from materials and labour. Current trend of engineering is oriented to meet both requirements increasing the rate of polymer matrix composites which implies association with structures made of titanium alloys. Hot forming can be used to reduce the production costs of titanium components: forging in closed dies of billets or semi finished form, in the temperature range where the Beta phase of titanium is stable, grants an adequate plasticity of the Ti-6Al-4V alloy, the most commercially used, allowing production of complex shapes with limited a…

What really causes large price changes?

2003

We study the cause of large fluctuations in prices in the London Stock Exchange. This is done at the microscopic level of individual events, where an event is the placement or cancellation of an order to buy or sell. We show that price fluctuations caused by individual market orders are essentially independent of the volume of orders. Instead, large price fluctuations are driven by liquidity fluctuations, variations in the market's ability to absorb new orders. Even for the most liquid stocks there can be substantial gaps in the order book, corresponding to a block of adjacent price levels containing no quotes. When such a gap exists next to the best price, a new order can remove the best q…

On the improvement of material formability in SPIF operation through tool stirring action

2012

Single-point incremental forming (SPIF) is a quite new sheet-forming process which offers the possibility to deform complex parts without dedicated dies using a single-point tool and a standard three-axis CNC machine. The process mechanics enables higher strains with respect to traditional sheet-forming processes, but particular attention must be given to the maximum forming angle. In this paper, a new approach is proposed to enhance the material formability through a localized sheet heating as a consequence of the friction work caused by elevated tool rotational speeds. AA1050-O, AA1050-H24, and AA6082-T6 were utilized, and the reached temperatures were recorded by thermocouples, fixed to …

Modelling Polycrystalline Materials: An Overview of Three-Dimensional Grain-Scale Mechanical Models

2014

International audience; A survey of recent contributions on three-dimensional grain-scale mechanical modelling of polycrystalline materials is given in this work. The analysis of material micro-structures requires the generation of reliable micro-morphologies and affordable computational meshes as well as the description of the mechanical behavior of the elementary constituents and their interactions. The polycrystalline microstructure is characterized by the topology, morphology and crystallographic orientations of the individual grains and by the grain interfaces and microstructural defects, within the bulk grains and at the inter-granular interfaces. Their analysis has been until recentl…

High bit rate optical pulses sources generation and microstructured chalcogenide fibers characterizations

2011

This memory of thesis s' registered voter in the context of the FUTUR project financed by l' ANR and concerning the development of optical functions for the high bit-rate transmissions in the Network heart and carries on very high rates optical fibers sources generation and the optical chalcogenide microstructured fiber characterization. For this purpose, we study the linear and non-linear characteristics of microstructured chalcogenide fibers conceived and realized in various collaborations within the framework of the ANR FUTUR project. For that a great number of characterizations methods were developed giving a comparison between a standard single mode fiber and these microstructured chal…

Rôle de l'image dans l'acquisition des compétences par le recours au marché de contrôle d'entreprises

2008

International audience

L'acquisition des compétences par le recours au marché de contrôle d'entreprises : une source d'avantage concurrentiel

2007

Pilna teikuma definīciju analīze 'Kobilda' vārdnīcās

2021

Šajā bakalaura darbā tiek pētītas pilna teikuma definīcijas un to īpatnības KOBILDA vārdnīcās. KOBILDA pilna teikuma definēšanas stils kļuva par pavērsienu vārdnīcu pasaulē, piedāvājot pilnīgi jaunu pieeju vārdnīcu rakstīšanai. Tādējādi bakalaura darbā ir iekļauti secinājumi, kas atspoguļo lietotāju attieksmi pret KOBILDA definīciju. Darba empīriskā pētījuma metode ir gadījumu izpēte, datu vākšanas tehnika – aptaujas anketēšana, kas ir analizēta no kvalitatīvā un kvantitatīvā viedokļa. Analīze atklāj, ka pilna teikuma definīcijas nav priekšroka salīdzinājumā ar citiem definīciju veidiem, jo lielākā daļa respondentu dod priekšroku tradicionālākiem definēšanas stiliem. Turklāt analīze rāda, k…

Larval fish assemblages in the central Mediterranean Sea: spatio spatio-temporal dynamics and biological effect on early life stage of Sardinella aur…

Suction controlled drying and wetting cycle effects on the volumetric behaviour of a lime-treated high plasticity clay

2016

The paper presents some experimental results collected on samples recovered from an experimental embankment obtained by compacting a lime-treated clay. Samples were collected soon after the in situ compaction and they were cured in controlled environmental conditions for at least 18 months. Mercury intrusion porosimetry tests (MIP) were carried out on freeze-dried specimens to characterize the microstructure of the material. In order to assess the durability of the improved material, laboratory tests focused on the effects of cyclic variations of the degree of saturation on the water retention properties and the volumetric behaviour of the stabilized clay. Collected results show that the li…