I.R. Harris

Bio: I.R. Harris is an academic researcher from University of Birmingham. The author has contributed to research in topics: Coercivity & Neodymium magnet. The author has an hindex of 47, co-authored 436 publications receiving 8962 citations. Previous affiliations of I.R. Harris include Leibniz Institute for Neurobiology & Jožef Stefan Institute.

An investigation of phase stability in the Y2O3-Al2O3 system

Abstract: The stability of the three known phases in the Y2O3-Al2O3 pseudo-binary system has been investigated. YAlO3 (YAP) and Y4Al2O9 (YAM) decompose at elevated temperatures, the products of the reaction being the third compound Y3Al5O12 (YAG) and an unknown phase (designated X). The decomposition is most evident in powders but can also be initiated on the surface of bulk single crystals. X-ray diffraction studies have been performed in an attempt to identify the structure and composition of the unknown phase. The thermal decomposition has been found to be surface controlled and an optical and scanning electron microscope study of the associated morphological changes in YAlO3 indicates that the reaction involves localized surface melting, probably with the loss of oxygen which effectively moves the composition off the binary join.

Rare earth intermediate phases: I. Phases formed with tin and indium

Abstract: Room temperature lattice spacings have been measured for twenty-one intermediate phases of the type R.E.Sn 3 and R.E.In 3 . Results indicate that in CeSn 3 , the cerium atoms are in a valency state similar to that in γ-cerium (effective valency approximately 3.1). In CeIn 3 , however, the cerium atoms are expanded, suggesting that in this case the effective valency is closer to 3. Thermal expansion curves from −186°C to room temperature have been determined for LaSn 3 , CeSn 3 , PrSn 3 , CeIn 3 and PrIn 3 , and from room temperature to 500°C for CeSn 3 , CeIn 3 , PrIn 3 , GdIn 3 , and YIn 3 . CeSn 3 is abnormal in that the coefficient of thermal expansion up to 140°C exceeds the typical value (LaSn 3 , PrSn 3 ), and the effects are consistent with variable occupancy of the 4f levels of the cerium atom, such that conduction band → 4f transitions are encouraged by increase in temperature. Minor abnormalities occur in the expansion curve of CeIn 3 .

Magnets in prosthetic dentistry

Abstract: Magnetic retention is a popular method of attaching removable prostheses to either retained roots or osseointegrated implants. This review chronicles the development of magnets in dentistry and summarizes future research in their use. The literature was researched by using the Science Citation Index and Compendex Web from 1981 to 2000. Articles published before 1981 were hand researched from citations in other publications. Articles that discussed the use of magnets in relation to prosthetic dentistry were selected. (J Prosthet Dent 2001;86:137-42.)

Hybrid porous solids: past, present, future

Abstract: This critical review will be of interest to the experts in porous solids (including catalysis), but also solid state chemists and physicists. It presents the state-of-the-art on hybrid porous solids, their advantages, their new routes of synthesis, the structural concepts useful for their ‘design’, aiming at reaching very large pores. Their dynamic properties and the possibility of predicting their structure are described. The large tunability of the pore size leads to unprecedented properties and applications. They concern adsorption of species, storage and delivery and the physical properties of the dense phases. (323 references)

Ferromagnetic materials

Abstract: In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Recent advances in the liquid-phase syntheses of inorganic nanoparticles.

Abstract: The development of novel materials is a fundamental focal point of chemical research; and this interest is mandated by advancements in all areas of industry and technology. A good example of the synergism between scientific discovery and technological development is the electronics industry, where discoveries of new semiconducting materials resulted in the evolution from vacuum tubes to diodes and transistors, and eventually to miniature chips. The progression of this technology led to the development * To whom correspondence should be addressed. B.L.C.: (504) 2801385 (phone); (504) 280-3185 (fax); bcushing@uno.edu (e-mail). C.J.O.: (504)280-6846(phone);(504)280-3185(fax);coconnor@uno.edu (e-mail). 3893 Chem. Rev. 2004, 104, 3893−3946

Magnetic materials and devices for the 21st century: Stronger, lighter, and more energy efficient

Abstract: A new energy paradigm, consisting of greater reliance on renewable energy sources and increased concern for energy effi ciency in the total energy lifecycle, has accelerated research into energy-related technologies. Due to their ubiquity, magnetic materials play an important role in improving the effi ciency and performance of devices in electric power generation, conditioning, conversion, transportation, and other energy-use sectors of the economy. This review focuses on the state-of-the-art hard and soft magnets and magnetocaloric materials, with an emphasis on their optimization for energy applications. Specifi cally, the impact of hard magnets on electric motor and transportation technologies, of soft magnetic materials on electricity generation and conversion technologies, and of magnetocaloric materials for refrigeration technologies, are discussed. The synthesis, characterization, and property evaluation of the materials, with an emphasis on structure‐property relationships, are discussed in the context of their respective markets, as well as their potential impact on energy effi ciency. Finally, considering future bottlenecks in raw materials, options for the recycling of rare-earth intermetallics for hard magnets will be discussed.

Storage of Hydrogen, Methane, and Carbon Dioxide in Highly Porous Covalent Organic Frameworks for Clean Energy Applications

Abstract: Dihydrogen, methane, and carbon dioxide isotherm measurements were performed at 1−85 bar and 77−298 K on the evacuated forms of seven porous covalent organic frameworks (COFs). The uptake behavior and capacity of the COFs is best described by classifying them into three groups based on their structural dimensions and corresponding pore sizes. Group 1 consists of 2D structures with 1D small pores (9 A for each of COF-1 and COF-6), group 2 includes 2D structures with large 1D pores (27, 16, and 32 A for COF-5, COF-8, and COF-10, respectively), and group 3 is comprised of 3D structures with 3D medium-sized pores (12 A for each of COF-102 and COF-103). Group 3 COFs outperform group 1 and 2 COFs, and rival the best metal−organic frameworks and other porous materials in their uptake capacities. This is exemplified by the excess gas uptake of COF-102 at 35 bar (72 mg g−1 at 77 K for hydrogen, 187 mg g−1 at 298 K for methane, and 1180 mg g−1 at 298 K for carbon dioxide), which is similar to the performance of COF...