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By Guo Xueyi

The reaction mechanism for the manganese dioxide reductive dissolution in acidic chloride media in the presence of ferrous/ferric ions are based on theoretical delineation and dual cell experiments. In terms of the Buttler-Volmer equation and chemical kinetic principles, a electrochemical kinetic equation was deduced, which successfully provided a theoretical basis for describing the role of Cl-, Fe2+, Fe3+ and H+ in solution, as well as their interrelationship in manganese dioxide reductive dissolution. Dual cell experimental studies indicate that the increases of Cl- and Fe2 in solution are helpful to accelerate the couple process; while, Fe3and Mn2+ hinder the coupled reaction to some degree. Higher acidity in solution is beneficial to the dissolution of MnO2. All the dual cell experimental results are consistent with the theoretical deduction. This study will be useful to understand the mechanism for the leaching of manganese nodules from the deep ocean, as well as the leaching of manganese dioxide ore from land.

Jan 1, 2003

By Jouko Kallionen

Advanced Flotation Technology is the application driven design of flotation cells to achieve the optimum performance for each type and grind of flotation. This can be applied to roughers, scavengers, cleaners and specialty cells such as those to float hydrocyclone underflows in both primary and regrind circuits in order to reduce overgrinding. Standard, engineered, components are matched to provide mechanism design and cell dimensions for each case according to feed parameters and flotation type. Advances in process control have been achieved with high level controls and operator information data. This has gained a higher degree of understanding of cell operation and ore type being processed. Excellent results of this Advanced Flotation Technology in large scale porphyric copper ore have been achieved and designs through 7000 cu ft (200 m3) are currently available for high capacity concentrators. This paper will detail how flotation cells are more responsive to the exact requirements of the duty specified.

Jan 1, 1999

By M. Ramprecht, M. Wu, A. Kharicha, A. Ludwig, H. Holzgruber

"The influence of the frequency of AC power supply on the magneto-hydrodynamic during the electroslag remelting process is studied. The focus is on the electrodynamic field and its resulting mechanical effects on the flow and liquid interfaces. The possible influence of the electrochemistry on the droplet formation is qualitatively discussed.IntroductionThe electroslag remelting (ESR) process is a secondary melting technique which can be used for a variety of metals and alloys, provided appropriate fluxes (slags) and melting parameters are employed. The ESR process is presently operating mostly with AC current of about 50 Hz. However for reasons primarily of inductive losses in the electric circuit, furnaces for ingots larger than 1 m, use or are projected to use current of very low frequency (< 5 Hz). Effects of lower frequencies (2.5-5Hz) on macrostructure and non-metallic inclusions were recently studied by Chang [1]. Most of investigations were performed either with DC power or with AC of 50-60 Hz [2-4]."

Jan 1, 2012

By John A. Gisby

Phase equilibria for multi-component systems can be calculated reliably from critically assessed thermodynamic data for sub-systems using software packages like MTDATA, developed by the National Physical Laboratory, UK (NPL). Models and data resulting from an ongoing Mineral Industry Research Organisation (MIRO) project make such calculations possible for the complex systems encountered during sulphide smelting, involving interactions between matte, slag, metal, and gas phases. Predictive calculations can be made that are directly relevant to industrial processes, covering composition and temperature ranges beyond the scope of hard- copy phase diagram compilations, allowing the feasibility of more economic and environmentally sound routes to be explored, better choice of materials to be made, and pilot plant studies to ,be directed more efficiently. Current applications include the selection of suitable fluxing practices in copper and nickel smelting, analysing the operation of the Kennecott copper smelter, optimising the recovery of precious metals and investigating refractory wear.

Jan 1, 2002

By Clodualdo C. Conde

In order for Philippines Associated Smelting and Refining Corporation (PASAR) Corporation to remain a leader in the copper smelting and refining industry, continuous improvements in plant technology are required. Reliable performance of plant equipment is essential for a competitive smelting operation. PASAR is constantly searching for the best equipment and technology to allow us to manufacture products more efficiently. When the Smelter was commissioned in 1993, the Flash Furnace off-gas treatment system was a constant source of problems. There were frequent shut-downs of the electrostatic precipitator due to material buildups on the discharge electrodes and collecting plates. In 1998, the precipitator was successfully upgraded to eliminate the buildup problems and to increase the collection efficiency. The upgrade greatly reduced down time and maintenance, and the enhanced collection efficiency also eliminated pluggage problems and material losses in the Acid Plant. This extensive precipitator upgrade was accomplished during a 30-day Smelter turnaround.

Jan 1, 1999

By James Wang

In July 2003, The Office of Hydrogen, Fuel Cells and Infrastructure Technologies of the Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy solicited Grand Challenge Proposals to establish three Centers of Excellence in hydrogen storage developments for reversible metal hydrides, non-reversible chemical hydrides and carbon storage materials, respectively. The program mission is to research and develop cost-effective, on-board hydrogen storage systems that enable a minimum range of 300 miles within the weight and volume constraints of the vehicle. Currently, no hydrogen storage technology available can meet the DOE cost and performance targets. In April 2004, Sandia National Laboratories was selected by DOE to lead the Metal Hydride Center of Excellence with partners from 5 other national laboratories. We will present the organization and recent accomplishments of the Metal Hydride Center which is confident to accomplish DOE/FreedomCAR and Fuels Partnership objectives for 2010 in hydrogen storage for vehicular transportation applications.

Jan 1, 2006

By Musa Karakus

Zirconia-based refractorics arc finding increasing use for specialized applications in steelmaking technology, making optimization of their resistance to corrosion by steelmaking slags more important. Samples of calcia- and magnesia-stabilized zirconia refractories have been exposed to slags in the CaO - FeO - SiO, system at 155WC for the purposes of measuring corrosion rates. Examination by SEM/EDX and cathodoluminescence of the mineralogy of the attacked specimens reveals important clues about the mechanism of attack.

Jan 1, 1992

By K. Osseo-Asare

Aqueous stability diagrams (25°C) are presented for the systems M-H2O and M-Oxalate-H2O where M=Sm, Nd, Co, and Fe. With the aid of these diagrams (i.e., Eh-pH and log[Metal]- log[Oxalate]), the solution-chemical constraints on metal dissolution and precipitation are identified. By comparing the corresponding stability diagrams, conceptual flowsheets are developed for metal recovery from Sm-Co and Nd-Fe-B magnet scrap.

Jan 1, 1997

By Mark Cross, Hadi Abou-Chakra, Nicholas Christakis, Mayur K. Patel, John Baxter, Ugur Tiizful

"In recent years significant effort has been put into using continuum mechanics for the description of granular flows. Although these models are partially successful in capturing some flow characteristics, they lack essential information on material properties, which are needed to account for the interactions between different particles. Thus, they are incomplete and can not be used to describe processes such as hopper filling/emptying and pneumatic conveying, where particle-particle interactions can lead to phenomena such as segregation, degradation and agglomeration. In this paper, a 3-D unstructured finite-volume framework is presented, which employs interface tracking techniques to solve for the individual material components of the granular mixture in the bulk and thus, determine the material-air interface. Various transport processes, arising from the micro-mechanical properties of the different particle species in the granular mixture, can be obtained through kinetic theory. The transport coefficients of each of the individual species can be determined and analysed in a micro-mechanical framework and the transport process parametrised in the form of constitutive models. These models provide the continuum theory with information on the micro-mechanics.This work describes the continuum framework and the micro-mechanical parametrisations, which are used to describe the processes and interactions at the microscopic level. Numerical simulations and comparisons with experimental data are then presented for the case of binary granular mixtures and conclusions are drawn on the capability of the model to realistically predict and quantify the main characteristics of granular flows."

Jan 1, 2001

By Yongqi Sun, Zuotai Zhang

Our study investigated the influence of P2O5 and B2O3 on the viscosity and crystallization behavior of Ti-bearing blast furnace (Ti-BF) slags for the purpose of Ti extraction. The investigation of the crystallization behaviors were carried out using a single hot thermocouple technique (SHTT) and the viscosity was obtained by rotating cylinder method. For the viscosity, the results showed that P2O5 substantially increased the slag viscosity. P2O5 is a network-forming oxide, which increased the degree of polymerization of slags and accordingly increased the slag viscosity. However, both of slag viscosity and apparent activation energy for viscous flow remarkably decreased with B2O3 addition. As a typical network forming oxide, B2O3 was introduced into the network and existed dominantly as 2-D structure, BO3 triangular, which caused a simpler structure and a decreasing slag viscosity. As for the crystallization behaviors of Ti-BF slags, both P2O5 and B2O3 enhanced the crystallization trend of rod-shape rutile and suppressed the crystallization trend of dendrite CaTiO3. Therefore the added P2O5 and B2O3 caused the primary phase change from CaTiO3 to rutile. Additionally, it was found that the rod-shape rutile showed a 1-D growth, whereas the dendrite CaTiO3 showed a 3-D growth style.

Jan 1, 2015

By Shantanu Chakrabarti, Khursid Alam Khan

"Globally, the use of metallic coated steel sheets in the automobile industry is increasing. The sheet should have excellent formability, weldability, paintability and corrosion resistance. Since bare cold rolled steel sheets have certain limitations, application of galvanized steel sheets is steadily expending. Galvannealed steel sheet fulfills all requirements and has become of major interest in the automobile industry.The success of Galvannealed (GA) steels in the body-in-white depends upon material design and parameters of various processes involved, like cold rolling, continuous annealing, hot dipping and galvannealing. In the present work, powdering resistance, one of the important product characteristics of GA, has been studied and a relation is established between the process parameters and the powdering value. The product obtained through optimization of the process parameters have been successfully used by major automotive producers without any powdering problem, for internal as well as external automotive applications.IntroductionThe present automotive industry demands that steel for the auto components should have excellent formability, weldability, paintability, corrosion resistance etc. In addition to this there is specific requirement for some particular components like high surface quality for skin panels. Corrosion resistance of panels is important requirment which determines the life of the particular component and brand value of the automotive. Among all the zinc based steel coating used in the automotive industry coating produced by Galvannealing process has received most attention because of its excellent weldability along with superior corrosion resistance and better paintability."

Jan 1, 2012

By K. Rajani Kanth

Environmental problem is the major concern for any industry and there is a great need to that along green lines. Sangam Dairy being one of the most famous and wide spread Dairies in India, produces wide spectrum of milk products. The BOD levels of effluent water of this industry with MIF treatment were found to be around 100 ppm. Lot of research has been expended in the past to bring down the BOD levels to bare minimum. The main objective of the present study is to minimize the BOD level to the required level stipulated by environmental standards by employing various seeding materials. For this purpose microbes like Bacillus Subtiles, Pseudomonas, Aspergillas, Staphylococcus, and Pencilium have been employed and BOD levels were analyzed. Various Reagents, solutions with different dilution levels have been successfully prepared. Initial and final Dissolved Oxygen levels were determined before and after incubation. From the DO data, BOD was evaluated for all samples and comparison analysis of various seeding material was carried to suggest the efficient seeding material for the ETP plant. In the process, solutions of different dilutions have been prepared using difficult reagents. These samples are treated with above mentioned microbes and BOD levels are estimated. It has been observed that staphylococcus and Pseudomonas proved to be the best seeding materials. When there microbes have employed BOD levels fall to less than 10 and 20 ppm respectively

Jan 1, 2006

By T. S. Krishnan

Among the established permanent magnets, SmCo5 magnet occupies the foremost position as it offers a unique combination of high energy product, coercivity and curie temperature. The SmCo5 magnets are thus extensively used for high field applications. These are also best suited for use in environments where high demagnetising field and high temperature are operative. Also, for applications where high performance and miniaturisation are the over-riding considerations, the choice again falls on SmCo 5 magnets. The main deterrent to the widespread use of SmCo5 magnet is its high cost. Both samarium and cobalt metals are high priced, and the magnets prepared from their directly melted alloy are thus naturally very expensive. An alternate process involving calcium reduction of their oxide intermediates has, therefore, been studied and the alloy prepared by this process has been evaluated and found satisfactory for magnet production. The process essentially involves compaction of the charge mix containing samarium oxide, cobalt oxide (or metal) and calcium metal and&apos; reduction of the charge compact at 1000-1300°C in hydrogen atmosphere, followed by water and acid leaching, drying and classification. The calcium reduction process offers three distinct advantages over the conventional melting processes: (i) The oxide intermediates are relatively cheaper and do not pose any handling problems. (ii) The operation temperatures are comparatively lower and hence precise composition control is possible as samarium losses due to volatilisation

Jan 1, 1989

By M. Cowling, S. Kumarl, A. W. Piper, R. A. Forsdick, C. Bailei, M. Patell

"The lead-refining process takes place in hemispherical vessels called kettles. In these kettles, lead-bullion is mixed at a certain temperature to remove impurities from the melt. This paper presents steps in a novel method for calculating vortex shape and flow field in the refining kettle using Computational Fluid Dynamics (CFD). First of all a two-dimensional axisymmetric model is used to calculate the vortex shape at the liquid-air interface. Here action of impellers and baffles are accounted for by adding source and sink terms to the appropriate momentum equations. The model includes Yolume of Fluid (YOF) method to predict the shape of interface deformation, i.e. vortex. This strategy reduces the computationally intensive three-dimensional transient simulations to a more efficient two-dimensional model. The calculated vortex shape is then used to regenerate a full three-dimensional grid. This grid is used to carry out steady-state simulation using the standard multiple-reference-frame method of impeller-fluid-baffle interaction within the commercial code Fluent. Simulation results for both stages of the development are compared with experimental data.IntroductionOne of the most important steps in Lead Refining process is impeller stirred mixing of Lead Bullion in hemispherical vessels. During this process, the melt is treated with one or more reagents in order to remove impurity elements such as copper, antimony, silver and bismuth. These impurities react selectively with the reagents and float to the melt surface in the form of a powdery layer, which is then skimmed for further processing. Figure-! shows (a) the lead refining kettle and (b) the schematic representation of involved flow pattern. Stirring of the lead bath using specific impeller designs, which creates a central vortex, provides a mechanism for draw-down and dispersion of the buoyant reactants. Clearly, effective control of the impeller generated vortex and flow pattern is crucial to achieving efficient operating conditions."

Jan 1, 2001

By N. Ono, H. Fujiwara, S. Otsuka-Yao-Matsuo, T. Omata

"The electrical conductivity and the oxygen release and uptake of sintered indium tin oxide (ITO) upon heating and cooling under the condition that P(O2)/P*=4.9X10-4 (P* = atmospheric pressure), :when P(O2) was approximately 50Pa, were simultaneously measured by using a closed-system oxygen-gas analyzer. A large increasing in -the electrical conductivity - upon the· oxygen release detected in 1130<T<1273K was observed. Quantitative relationship between the number of oxygen atom released from ITO and the conduction electron density in ITO was studied. The release of one oxygen atom agreed with the generation of two conduction electrons, i.e., the efficiency-carrier-generation for the oxygen release from the ITO was almost one. The oxygen atom released must be originally at the quasi-anion site in the C-type rare-earth lattice, i.e., the 16c site in the space group of Ia3, as an interstitial excess oxygen, Oi"". It was concluded that the mechanism of conduction carrier generation and compensation upon SnO2 doping into In2O3 can be expressed by the defect equation, 2SnO2-2Sn1n +2(1-z)e'+zOi""+3O0 x+(l-z)/2O2, and that the oxygen release bringing the increase in the electrical · conductivity can be expressed by the equation, Oi""-1/2O2+2e'.IntroductionThin films of SnO2-doped In2O 3 (generally designated as ITO, for indium tin oxide), which have high optical transparency for visible light and high electrical conductivity, have been used as transparent electrodes for liquid crystal and electrochromic displays. It is well known that the electrical conductivity of ITO depends on the content of SnOi-dopant and oxygen. However, a reliable relationship between electrical conductivity and the absolute oxygen content in ITO has yet to be reported. The elucidation of such a relationship is one of the important clues for realizing extremely highly conductive ITO electrodes."

Jan 1, 2000

By Jian Pan, Zhen He, Deqing Zhu, Shouyan Yue

"The differences of raw material characteristic among six kind of iron concentrates and the influences on ballability were studied from the aspect of the size distribution, specific surface area and particles morphology. The results show that the specific surface area of iron concentrates has crucial influence on ballability, and the effective method of improving ballability for weak ballability iron concentrate has been found. It is of important guidance for Chinese steel mills to import and use iron concentrate from the whole world.IntroductionChina's steel industry has developed rapidly in recent years, crude steel production in 2011 is an unprecedented 683 million tons, which is almost half of the world crude steel production, and it is equivalent to the total sum production of the nations which rank at 2,3,4,5 and 6 in the world [1]. In order to match the development of steel industry, the blast furnaces are becoming larger and more modernization, therefore charging burden of higher quality is requested, and the reasonable blast furnace burden structure is more and more important, at the same time, for iron ore powder sintering process's continuous improvement and development, another method providing ""concentrate"" for blast fumace-pelletizing is also taken seriously. The grate-kiln method of pelletizing has achieved great development for its unique advantage, and in just a few years, there are over 60 rotary kiln production lines have built or being built in China, the sum of pellets has reached to more than 140 million [2, 3]. The rapidly growth of pelletizing yield demands diverse source of pellet, which include not only domestic magnetite concentrate, but also imported hematite which is high in iron and low in silicon. Usually the ratio of imported hematite concentrate increased gradually. The imported hematite concentrate has high grade and fine particle size (the content of -0.074 mm mostly higher than 90%), but the ballability of part of the concentrates is poor."

Jan 1, 2013

By Camila Martini Matos, Maria das Graças da Silva Valenzuela, Francisco Rolando Valenzuela Diaz, Lucy Gomes de Sant' Anna, Orley de Oliveira Magalhães, Flavio M. S. Carvalho, Isaac Jamil Sayeg

"Kaolin clays are widely used in various industry segments. Its main properties are fine granulometry, chemical inertness and whiteness. In general, kaolins are not easily organophiilized as a result of its 1: 1 structure. The aim of this paper is to describe the modification of a Brazilian kaolin sample, in order to obtain an organophilic kaolin of high performance. The clay as received was identified by X-ray diffraction and characterized by optical microscopy, cation exchange capacity and swelling tests for observation of their performance in water and organic solvents. Then, the sample was treated with a 10% sodium carbonate solution and with ammonium quaternary, washed several times with distilled water, dried at 60°C, and characterized by XRD and swelling assays. Our results show that the clay was organophiilized and its ability to swell in organic solvents has increased.IntroductionThe kaolin clay, also known as ""china clay"" is chemically a hydrated aluminum silicate characterized as a very fine powder and lamellar structure (1:1), being constituted mainly by kaolinite [l]. Kaolin is a mineral extremely used as raw material. Its properties such as color, softness, small particle size and chemical inertness make it a suitable material for several industrial applications. The desired properties of kaolin varies widely for each application, beginning with its largest use in the paper industry until minor uses in the sectors of cosmetics and pharmaceutics. These two last applications require purified kaolin with defined functionality [2]. To find improvements in the functionality of kaolin for specific applications is important for many industrial uses. Sometimes the way to find these improvements might be modification of the kaolin clay by treatment with a chemical substance as ammonium quaternary, causing surface modifications [3,4]. In this work is described the modification of a Brazilian kaolin sample by treatment with cetyl trimethylammonium chloride (CTAC). The properties of the modified kaolin are being assessed by characterization and essays to understand its functionality and industrial application."

Jan 1, 2013

By C. A. Nogueira, F. Pedrosa, F. Margarido, R. N. G. Guerra

"A hydrometallurgical process for recycling spent Zn-MnO2 batteries was developed, involving leaching with sulfuric acid, purification by precipitation and metals separation for further recovery. Leaching of zinc oxide was easily attained while for manganese oxide was rather difficult depending on temperature and acid concentration. At 90°C and with the liquid/solid ratio of 20 L/kg, more than 95% of zinc is recovered in 30 minutes with 0.5M H2SO4. To attain similar recovery for manganese, higher levels of acid concentration and time are needed (e.g 0.7 M and 2 hours). After leaching a purification step is necessary to remove iron co-dissolved through Fe(III) precipitation. Separation of zinc from manganese by solvent extraction with 1M DEHPA follows in the process route. The countercurrent multistage separation diagram developed allows the production of a zinc electrolyte with 120 g/L Zn and 0.005 g/L Mn, and a raffinate with 16 g/L Mn and 0.013 g/L Zn.IntroductionThe recycling of spent Zn-MnO2 batteries is carried out by dedicated recyclers using several process alternatives [1]. Most of the running processes use pyrometallurgical technologies [2] based on zinc distillation. Alternative treatments by hydrometallurgy have been reported [3-5] but its application is scarce.In order to contribute to the development of alternative solutions, a process for recycling batteries based on Zn-MnO2 systems has been studied. The process is based on the hydrometallurgical treatment of spent batteries in sulfuric acid media (Figure 1). The process starts with the physical processing by shredding using cutting grinders, where the batteries are opened and size reduced, allowing the liberation of the interior electrode particles or pastes. The fines can be then separated and the coarse material containing the steel scrap can be treated to remove the remaining aggregate electrode. The final scrap also contains some plastics and other non-metal materials and can be further valorized."

Jan 1, 2008

By E. Yegan Erdem, Fiona M. Doyle, Alyssa A. Maich

"There is an expanding interest in synthesizing high quality magnetic nanoparticles, most notably for biomedical applications. Different processing routes have been reported for the synthesis of magnetite and maghemite. However, some ambiguity remains on their precise chemistry, intermediates, and final products, due to the structural similarity of maghemite and magnetite, and the relative ease of redox transitions during synthesis. Here we present the results of TEM, x-ray and electron diffraction, and SQUID studies aimed at characterizing the products from two different reaction systems, thereby clarifying the reaction chemistry. The first system hydrolyzed aqueous FeCh and FeCb chlorides with ammonia in a micro fluidic reactor at ambient temperature; although the reaction product displayed a uniform distribution, it included non-magnetic goethite and lepidocrocite. If the aqueous solutions contained dissolved oxygen, there appeared to be extensive oxidation of Fe(II). The second system thermally decomposed iron (III) acetylacetonate in ether. In prior studies, oleylamine has been reported to serve as both a reducing agent and capping ligand to control particle characteristics; however, our studies revealed little reduction, with maghemite dominating the reaction products.IntroductionMagnetite and maghemite nanoparticles are co=only used in ferrofluids, in medical applications, and in drug delivery. Superparamagnetic properties, along with low cytotoxicity, colloid stability and bioactive molecule conjugation capability, make these nanomagnets ideal for both in-vitro and in-vivo biomedical applications [1]. One of the major constraints on widespread adoption of nanoparticles for these applications is the amount needed. Typical batch synthesis methods produce polydispersed nanoparticles, which require further size selection procedures to isolate the mono disperse nanoparticle population needed for many applications. In order to maximize the yield of usable particles from a synthesis operation, the reaction conditions must be closely controlled. This requires full knowledge of how the reaction conditions control the various aspects of nanoparticle growth. Many methods have been used to synthesize iron oxides, including sonochemical reactions, mechanochemical synthesis, hydrolysis and thermal decomposition. This work examines the latter two methods, focusing on oxidation and reduction of iron."

Jan 1, 2012

By Nourredine Menad, Christian Lucion, Maurice Save, Paul Hubaux, Solène Touzé

"The collection and treatment of WEEE has recently become mandatory in Europe and is now being organized. As the first step in current treatment processes is manual dismantling, we decided to investigate the development of an entirely automatic WEEE treatment procedure using physical separation techniques so as to limit manual sorting to the removal of hazardous components. Our approach was to test different wet and dry physical separation methods on bulk WEEE; i.e. gravity separation (jig and pneumatic table), electric conductivity separation (eddy currents), and particle shape separation (Lavodune classifier and vibrating helical conveyors). The results enabled us to determine a global treatment flowsheet of shredding, electromagnetic separation, eddy current separation, screening (2 mm), sink&float separation (d=1), and jigging. All the end products, except for the fine fraction, have possible recycling outlets. Batches of WEEE can thus be treated automatically once the problem of non-ferrous wires is resolved.IntroductionAccording to Ademe (French Agency for Environment and Energy Management; www.ademe.fr), France's annual production of WEEE is between 1.7 and 2.0 million tonnes. This waste, although of very varied composition, consists mainly of plastics and metals, and its collection and treatment has been mandatory in France since 2006; the modalities are gradually becoming organized. Existing treatment processes rely on a first step of manual dismantling which, though essential for removing dangerous components from the WEEE (e.g. batteries, cathode-ray tubes, ink cartridges, etc.), also includes separating out the decimetre-size plastic parts and metal parts. No fully automatic process has yet been developed for this type of waste. Moreover, the dismantling units in Europe are highly subsidized and call upon social workers. As this situation is not conceivable for the long-term, it is obviously important to develop entirely automatic WEEE-treatment technologies based on physical separation techniques. This would limit manual sorting to the removal of toxic components."

Jan 1, 2008