The mechanisms of boiling (video)
Boiling is an effective way to remove heat. It is used as cooling medium in many industrial power such as power plants. The mechanisms governing the different regimes occurring during the boiling of a liquid usually are complex and often intertwined. It is important to know them and identify them in the laboratory. In particular, the detailed understanding of the boiling crisis, well known and feared for the damage that can result in practice is of primary importance. (For the boiling of a s
Асимптоти
Liljana Stefanovska
Се дефинира поимот за асимптота и се дефинираат три вида асимптоти: вертикална, хоризонтална и коса асимптота.
1.7.1 Protein balance
This Unit studies 'proteins'. Starting with a simple analysis of the molecular make up, the Unit moves on to look at the importance of protein and how they are digested and absorbed
1.8 Summary
This Unit studies 'proteins'. Starting with a simple analysis of the molecular make up, the Unit moves on to look at the importance of protein and how they are digested and absorbed
L'autorité -Yves Michaud (audio)
Une conférence de l'UTLS au lycée
L'autorité par Yves Michaud (philosophe)
Lycée Pasteur (59 Lille)
Cu 21, Sn 79 (wt%), peritectic transformation
This microstructure is generated via a peritectic reaction (L+ε = η), which bears some similarities to the more familiar eutectic reaction (L = α + β). Upon cooling from the liquid phase field, primary ε is formed, which can be seen here as a slightly darker phase than the sheath of η surrounding it. The η sheath is the product of a peritectic reaction between ε and liquid. The peritectic reaction rarely goes to completion, since the formation of η around the ε phase separates it from
Cu 21, Sn 79 (wt%), peritectic transformation
This microstructure is generated via a peritectic′s reaction (L+ε = η), which bears some similarities to the more familiar eutectic reaction (L = α+β). Upon cooling from the liquid phase field, primary ε is formed, which can be seen here as a slightly darker phase than the sheath of η surrounding it. The η sheath is the product of a peritectic reaction between ε and liquid. The peritectic reaction rarely goes to completion, si
West Nile Virus Problem Space
As an emerging disease in the public eye, WNV continues to generate scientific interest as well. Researchers are exploring questions about its origin, evolution, transmission by multiple vectors and host tissues, replication in multiple hosts, viremic period, viral loads, seroconversion and antibody production, detection, vaccine potential, etc. Central to these investigations are the use of molecular data including nucleic acid sequences and the use of bioinformatics.
Fracture surface in a liquid crystalline polymer
Above their melting point, liquid crystalline polymers exhibit a mesophase within which, although able to flow and are not arranged in a crystal, they exhibit long range orientational order. This molecular alignment can be exploited to make high strength and stiffness fibres such as Kevlar, or even mouldable thermotropics such as Vectra. Molecular alignment can also be controlled by an external applied field; a property exploited in liquid crystal displays. This specimen has not had a magneti
Fracture surface in a liquid crystalline polymer
Above their melting point, liquid crystalline polymers exhibit a mesophase within which, although able to flow and are not arranged in a crystal, they exhibit long range orientational order. This molecular alignment can be exploited to make high strength and stiffness fibres such as Kevlar, or even mouldable thermotropics such as Vectra. Molecular alignment can also be controlled by an external applied field; a property exploited in liquid crystal displays. This specimen has not had a magneti
Spherulites in poly-3-hydroxy butyrate (PHB)
Polymer melts often crystallise from heterogeneous nuclei to form ribbon-like lamellae, which have a folded chain molecular structure. They commonly radiate outwards from the nucleation point, to form spherical features called spherulites - which are often quite large. The characteristic Maltese cross pattern, seen when viewed between crossed polars, results from isoclinic fringes formed when one of the principal vibration directions is approximately parallel to the polariser. In some cases
Injection-moulded polypropylene (PP) hinge
The colours in the image are the result of birefringence and relate to the residual strain in the polypropylene. The pattern of strain is indicative of the flow of material during the injection process and reveals the molecular alignment in the constriction which constitutes a hinge. The aligned molecules provide a fatigue resistant, flexible joint. A sprue which has been cut off is also visible in the top left-hand corner of the image.
Injection-moulded polystyrene (PS) case
The colours in the image are the result of birefringence and relate to the residual strain in the polystyrene. The pattern of strain is indicative of the flow of material during the injection process and it highlights the injection point (known as a 'sprue') which can also be identified by a small lump on the surface; the molecular alignment is greatest near this point. Towards the edges of the ruler and along its length, the material becomes more relaxed and as the molecular alignment falls,
Injection-moulded polystyrene ruler
The colours in the image are the result of birefringence and relate to the residual strain in the polystyrene. The pattern of strain is indicative of the flow of material during the injection process and it highlights the injection point (known as a 'gate') at the end of the ruler; the molecular alignment is greatest near this point. Towards the edges of the ruler and along its length, the material becomes more relaxed and as the molecular alignment falls, the retardation of light is less. If
Fe, C 0.5 (wt%) steel, near a decarburised surface
This is a hypoeutectoid steel (one that has a carbon composition below that of the eutectoid). During original cooling from high temperature, some ferrite was formed first on the prior austenite grain boundaries and the remaining carbon-enriched austenite then transformed to pearlite in a eutectoid reaction. The specimen was then exposed to a decarburising atmosphere (just air in this case). This might happen inadvertently, or it could be done deliberately if a softer surface is required for som
Numerical Methods Applied to Chemical Engineering, Fall 2001
Numerical methods for solving problems arising in heat and mass transfer, fluid mechanics, chemical reaction engineering, and molecular simulation. Topics: numerical linear algebra, solution of nonlinear algebraic equations and ordinary differential equations, solution of partial differential equations (e.g. Navier-Stokes), numerical methods in molecular simulation (dynamics, geometry optimization). All methods are presented within the context of chemical engineering problems. Familiarity with s
Physics in architecture
Developed in 1998 by Dr John Whittle (Department of the Built Environment) using Authorware, this package contains brief interactive notes on eight areas of physics in which architects need a working knowledge. However, it is also useful to others in science, engineering and social sciences looking for an introduction to the topics concerned. These topics are: Units of measurement; Scalar and vector quantities; Newton’s laws; Mass and weight; Action and reaction; Waves; Heat, work and energy;
7.340 Learning and Memory: Activity-Controlled Gene Expression in the Nervous System (MIT)
The mammalian brain easily outperforms any computer. It adapts and changes constantly. Most importantly, the brain enables us to continuously learn and remember. What are the molecular mechanisms that lead to learning and memory? What are the cellular roles that activity-regulated gene products play to implement changes in the brain?How do nerve cells, their connections (synapses), and brain circuits change over time to store information? We will discuss the molecular mechanisms of neuronal plas
6.701 Introduction to Nanoelectronics (MIT)
Traditionally, progress in electronics has been driven by miniaturization. But as electronic devices approach the molecular scale, classical models for device behavior must be abandoned. To prepare for the next generation of electronic devices, this class teaches the theory of current, voltage and resistance from atoms up. To describe electrons at the nanoscale, we will begin with an introduction to the principles of quantum mechanics, including quantization, the wave-particle duality, wavefunct
