The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Ultracapacitors: Why, How, and Where is the Technology

Intermolecular And Surface Forces

A considerable part of the available literature on scandium in aluminium alloys is reviewed. Experimental data and assessments of the binary Al–Sc phase diagram, a wide range of ternary Al–Sc–X phase diagrams and a few higher order phase diagrams are accounted for, with emphasis on the aluminium rich part of the diagrams. The phase which is in equilibrium with Al, Al3Sc, can form by several different mechanisms, all of which are described. The precipitation kinetics of Al3Sc in binary Al–Sc alloys are discussed, and an overview of the reported influences of ternary alloying elements on the precipitation of Al3Sc is given. The Al3Sc phase particles can serve as a grain refiner in the Al melt, a dispersoid for controlling the grain structure of the alloy and a strengthening precipitate. Several examples of these three effects are mentioned, both in binary Al–Sc alloys, and in more complex alloys. The reported effects of Sc on the precipitation behaviour in Al–Cu, Al–Mg–Si, Al–Zn–Mg and Al–Li alloys ...

http://www.arc.nucapt.northwestern.edu/refbase/files/Royset-2005.pdf

Scandium in aluminium alloys

Photocatalytic degradation of organic pollutants using TiO2-based photocatalysts: A review

Over the last 40 years, the commercial production of titanium and its alloys has increased steadily. Whilst these materials have some very attractive properties, enabling applications in many industries, they are seldom used in mechanical engineering applications because of their poor tribological properties. This paper starts with an introduction to the titanium material and a review of the different types of surface treatment. The processes of nitriding, oxidation and carburizing are among the most popular thermochemical treatments aiming at improving the surface properties of Ti-alloys. Different kinds of nitriding are investigated like plasma nitriding, ion nitriding, and laser and gas nitriding. The kinetics of nitriding and the conditions for the formation of nitrided layers are studied. The influence of the main processing parameters such as temperature, time on the microstructure and the formation of new phases during the processes of nitriding is discussed. Also based on investigations presented in the literature, the effects of nitriding on the microhardness and the corrosion resistance of titanium and titanium alloys are analyzed. The improved mechanical properties, which arise from these thermochemical treatments, are discussed in relation to the potential for applying these alloys to different industries.

Enhancing the microstructure and properties of titanium alloys through nitriding and other surface engineering methods

Degradation of aluminum metal matrix composites in salt water and its control

The eastern coast of Saudi Arabia has one of the most corrosive environments in the world. Dhahran is therefore an ideal location for the study of atmospheric corrosion. One out of every seven cars in the region is corroded. The atmosphere is contaminated by SO2 and a high concentration of suspended particulate matter (SPM) containing sand, salt and carbon particles, exceeding the World Health Organization (WHO) and Middle East Environmental Protection Agency (MEPA) limits most of the time. Corrosion proceeds in the Dhahran atmosphere at a R.H. as low as 40 per cent. At locations close to the sea (1.5 Km), β‐FeOOH is the major corrosion product and α‐ and γ‐FeOOH with some aluminates, silicates and hydrocarbons the minor products. At a location remote from the sea α‐ and γ‐FeOOH are found to be the major corrosion products as shown by XRD and FTIR spectroscopy. The concentration of hydrogen ions, chloride ions and SO2 appears to control the corrosion process during the initial exposure period up to one year and the adsorption of anions on the corrosion product films in the later period.

Effect of environmental factors on the atmospheric corrosion of mild steel in aggressive sea coastal environment

Physico-Chemical Wastewater Treatment and Resource Recovery

THE DEVELOPMENT OF metal matrix composites has been a major breakthrough in materials in the last twenty years. The quantum leap in recent years has clearly established their potential for weight-critical applications in engineering components and structures in aerospace. Most of the attention, in the last decade, has been focused on aluminum as metal matrix because of its light weight, good mechanical properties and formability, economy and high resistance to environmental degradation. Aluminum alloys with tensile strengths as high as 687 MPa and with excellent resistance to corrosion are now available. Aluminum has capability of incorporating a wide variety of reinforcing agents, such as Al2O3, graphite fibers, whiskers, SiC and other particles. Aluminum alloys have an inherent compatibility with seawater and a good history in handling steam and high purity water in power plants and applications in process industry. Major alloying agents used are copper, manganese, silicon, magnesium, and minor elements, like nickel, titanium, chrome, lead, etc. Following is a summary of the effect of major alloying elements.

Mechanical Behavior and Fabrication Characteristics of Aluminum Metal Matrix Composite Alloys

It has been widely accepted that fossil fuels have played significance roles in human’s daily life and industrial developments. However, fossil fuels are associated with some problems like air pollution. Moreover, fossil fuels have limited sources in the world that will be finish‐ ed in near future if the consuming rate of fossil fuels does not decrease. So, scientists have been encouraged to find suitable sources of energy as replacements for fossil fuels.

/pdf/aluminium-alloys-in-solar-power-benefits-and-limitations-3twu8f8hjd.pdf

Zaki Ahmad

Papers

Degradation of aluminum metal matrix composites in salt water and its control

Effect of environmental factors on the atmospheric corrosion of mild steel in aggressive sea coastal environment

Physico-Chemical Wastewater Treatment and Resource Recovery

Mechanical Behavior and Fabrication Characteristics of Aluminum Metal Matrix Composite Alloys

Aluminium Alloys in Solar Power − Benefits and Limitations