Search results for "Solid"

WAVES PROPAGATION AND LIQUID ALUMINUM PARTICLE INJECTION IN SOLID ROCKET MOTORS

2013

A method to determine the injection of aluminium particles from the solid propellant burning surface to the core of the chamber in the presence of an acoustic wave field is developed and aluminum-droplet effects on propagation of acoustic waves in the flow of a solid rocket motor are analysed. Changes of the multiphase flow compressibility are calculated by taking into account both the translational and the pulsational motions of the aluminum droplets in consequence of the acoustic waves.

Lightweight Alloys Recycling and Processing through Innovative Friction Based Direct Technologies

In the last decades, the use of lightweight alloys has been spreading in almost any industrial field thanks to the relevant weight reduction allowed by the use of such materials. On the other hand, aluminium alloys are characterized by high-energy demands primary production cycles that are responsible for a relevant share of the global CO2 emissions. In order to limit and reverse such phenomenon, putting in place strategies to keep the material in the circle over multiple life cycles is mandatory and the concepts of circular economy, closed loop society and industrial symbiosis are progressively gathering more and more pace. Nevertheless, metal scraps are often mainly composed of chips resu…

Progresses in multi-materials billet manufacturing out of metal scraps through friction stir consolidation

2023

Abstract. The evolution of Friction Stir Consolidation (FSC) from recycling towards upcycling technique proved to be one of the excellent solid-state methods for manufacturing functionally graded billets. Multi-material Functional Graded Materials (FGMs) represent a novel class of materials characterized by a gradual change in properties and functions which can be tailored to enhance components performance. Manufacturing techniques play a critical role in achieving the designed compositional and microstructural distribution. Specifically, FSC allows the manufacturing of FGM billets out of metallic chips; the mixing of different metallic chips offers mutually exclusive mechanical properties …

Fundamental investigation on the mechanical behavior of weld seams

The solid state welding processes allow joints free from defects with reduced residual stresses and low distortion. However, such processes are generally characterized by a complex mechanical junction because of the particular material flow. Therefore, the design and optimization of the processes in which the solid bonding phenomenon occurs are difficult and requires a large number of tests. The purpose of this research is the description on the mechanical behavior of welded seams obtained through the friction stir welding (FSW) and linear friction welding (LFW) processes by analyzing the same phenomenon that occurs in both metallurgical processes, named the solid bonding phenomenon. The ai…

Learning Dynamic Geometry: Implementing Rotations

1995

This paper presents research in which we observed students of various ages and ability levels solving problems by using several pieces of software for solid geometry with different user interfaces. We evaluated the influence of the software on students’ learning, ways of reasoning, and the kind of mental images generated.

Solid state ionics and optical materials technology for energy efficiency, solar energy conversion, and environment control

1991

The fundamental electronic properties (including optical) of a solid are determined by the character of the interaction between its ionic and electronic subsystems. The state of the ionic subsystem can be changed persistently and reversibly by an external stimulus (current, light). The pertinent ion-controlled phenomena in the solids (solid electrolytes or mixed conductors) causes the ions to be inserted, extracted, transferred, or absorbed or transforms the states of the ions by redox reactions in the bulk or on the surface of the solid or on the interface of a (laminar or planar) solid ionic heterosystem. Several functions can be accomplished: (1) the optical response function of the soli…

Profesors Bruno Rolovs: biobibliogrāfiskais rādītājs

1991

Biobibliogrāfiskajā rādītājā ietverti fizikas un matemātikas zinātņu doktora profesora Bruno Rolova publicētie darbi no 1958.gada līdz 1990.gadam, kā ari literatūra par viņu.

Elektrisko un termoelektrisko īpašību pētījumi dažādu morfoloģiju organiskās plānās kārtiņās

2019

Promocijas darbs ir par organisko materiālu plāno kārtiņu elektriskajām un termoelektriskajām īpašībām. Pēdējos gadu desmitos funkcionāli organiskie materiāli konkurē un aizstāj klasiskos neorganiskos pusvadītājus saules baterijās un gaismu emitējošās diodēs, kur organiskie materiāli ir aktīvā sastāvdaļa, piemēram, organisko gaismu emitējošo diožu displejos dažādās portatīvās ierīcēs un ne tikai. Organisko materiālu salīdzinoši mazā elektrovadītspēja kavē to pielietojumu termoelektrisko ģeneratoru (TEG) jomā, tādēļ norit aktīvi pētījumi lādiņnesēju transporta izzināšanai organiskajos materiālos un tā uzlabošanai

Кинетика процессов рекомбинации в твердых телах: учет пространственной корреляции

1983

Электрохромизм и локализация носителей заряда в триоксиде вольфрама

1985

Advisor: Лусис, Андрей