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By J. Pereyra, M. DeMarco

"INTRODUCTION It can be vital that bolted joints holding subassemblies together remain secure. Bolts should resist the loosening effects of vibrations and dynamic loads yet need to be easily removable during maintenance. When a threaded fastener is subjected to vibration, the rapid movement causes a lowering of friction against the threads and a subsequent loss of preload. The loss of preload allows the fastener to vibrate loose and possibly fall out. As the diameter of fasteners increase desired preload becomes increasingly more difficult to achieve. Input torque requirements for achieving proper bolt preload is exponentially related to any given fasteners diameter. This means that specialized tooling or bolting practices are usually required to attempt the tightening of fasteners to reach their required preload. Traditional methods can cause problems with joint integrity and do not provide consistent bolt load across the bolted surface. BOLTED CONNECTIONS A failed critical bolted joint can lead to high maintenance costs, machine downtime, and risk to worker safety. Control of the clamp load in a bolted joint is vital. However, when faced with a problem joint, it is not surprising that the design engineer will not have an answer if asked about the clamp load. Torque calculations must always be based on the existing conditions that often are vague. Unless all parameters are correct, the calculation will be unreliable. Examples of parameters are: • Thread condition of the fasteners • Hardness of contact surface • Material (steel, aluminium, copper, etc.) • Extra friction from a locking fastener • Extra friction from an adhesive • Lubricant on the thread • Type of bolt head (flanged, regular or serrated) • Surface coating of the bolt • New or reused fastener During tightening, bolts are subjected to both tensile and torsional stress. The total stress in a bolt can be calculated using the formula: Total stress = vsx2 + 3txy2 In order to maximize the desired tensile stress (sx) it is vital to minimize the torsional stress (txy). Tensile stress (clamp load) is achieved when the bolt is axially elongated. Unwanted torsional stress (twisting) in bolts arises during tightening due to thread friction. High thread friction increases torsional stress and causes yielding at lower clamp load levels than normal. A lubricant is necessary to minimize the malign torsional stress. However, many commonly used bolt-locking systems are based on increased thread friction (deformed nuts, adhesives, etc). To minimize thread friction and concurrently safely secure the joint has often incorrectly been considered impossible. The use of locking systems that increase thread friction is the single most common reason why the full capacity of bolted joints is not utilized. The following example illustrates the problem."

Jan 1, 2015

By K. Sun, S. A. Argyropoulos

The assimilation and the exothermic behavior of Zn-Zr metallic powder compacts into molten aluminum was studied by measuring simultaneously the temperatures inside at the centerline of the compact, at its surface, and inside the molten aluminum bath, as well as the net downward force acting on the compact. In addition, the exothermic behavior of these compacts was also investigated in an argon protected atmosphere. The temperature rise inside the compact increases significantly with the mass ratio of zirconium in the compact and to a lesser degree with the aluminum bath temperature. Experimental results on the recovery of these compacts in molten aluminum will also be presented.

Jan 1, 2008

By Takashi Nakamura, Atsushi Iizuka, Yong Fan, Etsuro Shibata

The level of iron in typical copper slag reaches nearly 40% by mass, in the form of iron silicate. We designed a method to oxidize the nonmagnetic iron silicate to magnetite, permitting the selective recovery of the slag’s iron content by magnetic separation. This would effectively decrease the volume of dumped slag; the reclaimed iron could be used for iron and steel making. The crystallization behaviors of magnetite and hematite were studied as reaction products of the molten oxidation of copper slag. A gas atmosphere of 1% by volume of oxygen was found to effectively precipitate the slag’s iron content as magnetite.

Jan 1, 2015

By D Connelly

There is now a new generation of mobile crushing and screening plant systems available which have been developed based on the motivation of reducing truck haulage. Newly designed mobile crushing and screening plant systems have the advantages of mobility, flexibility, economy and reliable performance, making this system very appealing for small- to medium-sized projects or projects where a number of resources are separated by distance.A brief review of the past history and experience with transportable crushing plants provides an insight into some of the issues with transportable plants in mineral processing. A closer look at a simple model based on exploiting small but high-grade orebodies suggests the concept has merit, however there are many more engineering, logistics, legal, technical and management aspects which have limited the application of such a concept in the resource sector. This paper explores the concept in detail and endeavours to analyse the preferred commodities and scenarios under which the concept could be used and the economic and logistical limitations for iron ore. The paper also looks at the risk assessment criteria to be applied in selecting the type of resource projects where the model could be applied successfully. Other aspects considered in this paper are the project planning requirements, technical and economic feasibility, bankability and operability. Reference is made to the operating experience of contractors at a number of sites and feedback from the resource companies as managers of the projects.CITATION:Connelly, D, 2013. Mobile crushing and screening plant applications for small- to medium-sized iron ore projects, in Proceedings Iron Ore 20 13, pp 349-354 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By W. Rostoker, R. F. Domagala, R. P. Elliott

The phase equilibria of the Hg-Th system over the composition range 0-100 pct Th and temperatures up to 1000°C have been studied for a small-volume, closed system. The solubility of Th in liquid Hg is about 5 pct at 300°C and decreases sharply with decreasing temperature. Two intermediate phases occur, Hg3 Th and HgTh. The structures of these are hexagonal (nonideally close-packed) and face-centered cubic, respectively. The HgTh phase decomposes eutectoidally at 400°-500°C. The solubility of Hg in solid thorium seems to be negligible. AFULL-phase diagram for this system would have to be defined on temperature-composition-pressure co-ordinates. This paper describes the pseudo phase diagram of a closed system, that is, where the alloy enclosed in a small volume equilibrates with a vapor pressure of mercury dictated by composition and temperature. Because of the experimental difficulties in studying a system of this nature, many of the phase relations can only be sketched. Alloy Preparation Alloys over the full range of composition were made from triple distilled mercury and one of two grades of thorium. For the bulk of the work, a calcium-reduced metal in sintered pellet form of reported 99+ pct total thorium content was used. Arc-melted specimens of this thorium gave a hardness of 135 VPN. The microstructure showed small primary dendrites of ThO2. A number of alloy compositions were made with a high-purity, iodide-decomposition thorium metal. The are-melted hardness of a button of this material was 35 VPN. Although the microstructure of the arc-melted specimens showed no dendrites of ThO2, there was definite evidence of an unidentified phase enveloping the grain bound-aries. There were no distinguishable differences between the constitution of alloys made with the two grades of thorium metal. Under normal conditions thorium is not wetted by liquid mercury. The film of ThO2 on all thorium metal cannot be penetrated by either liquid or vaporous mercury. It was therefore necessary to comminute thorium in the presence of mercury under such conditions that oxide films could not reform on the newly exposed metal surfaces. This was accomplished by the use of a high-speed, carbide-tipped rotary cutter incorporated in a chamber purged with argon and connected at the bottom to a demountable Vycor bulb containing a weighed amount of mercury. This experimental device is fully described in a separate paper.1 Alloy compositions were calculated by weighing the empty bulb, the bulb containing the mercury, and the bulb containing the mercury and the thorium chips. Many alloys were analyzed chemically for thorium and/or mercury after subsequent homogenization; the agreement between analyzed and calculated compositions was invariably very close. Bulbs containing the requisite amounts of mercury and fine thorium chips were clamped off, removed to a sealing unit, evacuated and sealed. Amalgamation under these conditions proceeded rapidly even at room temperature. To insure homogeneity, the specimens were annealed to 300-400°C. Alloys containing less than 30 pct Th remained pasty after all treatments, indicating an equilibrium condition of liquid plus solid. Alloys with more than 30 pct Th were transformed into a dark powdery product. These latter specimens were annealed for times of up to 1 week to complete interdiffusion. Many of the alloy compositions are pyrophoric. On exposure to air they oxidize with considerable evolution of heat to a mixture of ThO2 and free mercury. It was mandatory that alloy specimens be handled in a "dry box" purged thoroughly with argon. All X-ray diffraction specimens were powdered, screened, and sealed in capillary tubes within the dry box. Experimental Procedures Thermal analysis experiments, useful only in the mercury-rich region of the system, were conducted with the alloys in their original containers. A reentrant thermocouple well formed an integral part of the bulb. These bulbs were heated in a silicone oil bath and cooled in a dry ice-acetone mixture. The rates of heating and cooling were slowed by immersing the specimen bulb in a larger tube containing silicone oil. This provided a suitable thermal lag. In all tests, pure mercury was run as a basic standard. While the invariant reaction at about the melting point of mercury was detected by thermal analysis, the heat effect at the liquidus was not sufficient to produce an inflection in the cooling curve. It was necessary to determine the liquidus temperatures at the mercury-rich end of the system by "breaks" in electrical reslstivity versus temperature curves for individual alloys. The apparatus for this purpose consisted of a pyrex tube about 2 in. diam and 12 in

Jan 1, 1959

By James Giulianelli

Personnel at the Jet Propulsion Laboratory (JPL) are studying the technology and applications of salt-gradient solar ponds (see below) for both electrical and thermal energy generation. The brine extraction and processing site operated by the Kerr-McGee Corporation at Searles Lake, California, offers ideal conditions for economic construction of solar ponds. Furthermore, since rising conventional energy costs adversely affect the economic recovery of brine by the present process, this site was selected for a study on the feasibility of integrating the solution mining of trona (Na2CO3?NaHCO3?2H20) in the lower salt with solar ponds for heating. The major emphasis of this study was to determine whether inexpensive thermal energy available at the brine extraction site would be useful in extracting increased mineral value from the resource. The present operation, which involves the simple extraction of the complex brine and its processing at the adjacent plant, is sometimes referred to as solution mining. Since the concept discussed in this paper involves injecting a heated sodium sulfate brine to dissolve carbonate underground, the proposed scheme is referred to as "enhanced" solution mining. The subject is discussed in greater detail in a recent JPL report. (1)

Jan 1, 1981

By Lewis. Clifford J.

The purpose of this article is to present design information and operating data on a pilot gas scrubber which is believed to be a new approach for removing noxious gases and particulate matter from the off gases of coal burning power plants and smelters. This principle of scrubbing gases, particularly, scrubbing with an aqueous slurry of lime, was conceived by the author early in 1972. The National Lime Association financed the design, fabrication and initial operation of the unit. The unit was fabricated by Hazen Research Inc. of Golden, Colorado. It has been tested on the off gases of two coal burning power plants and one smelter. The current environmental program has stimulated research and development activity directed toward the removal of sulfur oxides, oxides of nitrogen, particulate matter and other undesirable substances from gases discharged into the atmosphere. At present, most of this effort is focused on the removal of sulfur dioxide and particulate matter by aqueous scrubbing of the gases. This presentation deals particularly with the removal of sulfur dioxide using an aqueous slurry of lime as the scrubbing medium. In recent papers, the author has called attention to-the sludge problems resulting from aqueous scrubbing and to some earlier data on the pilot scrubber about to be discussed.1/

Jan 1, 1973

By Oliver C. Ralston

Nonmetallic technologic investigations of the U. S. Bureau of Mines are headquartered at experiment stations in three widely separated localities of the United States. During 1936, the Nonmetals Division of the Technologic Branch was formally set up by combining the direction off the work of these three experiment stations under one administration. The New Brunswick (N.J.) station which in the past has been known as the Nonmetallic Minerals Experiment Station, is henceforth to be at College Park, Md., as part of the Eastern Experiment Station, and its principal activities will be related to the nonmetallic resources of the Eastern and New England States.

Jan 1, 1937

By Fujio Ishii

The deoxidation of liquid nickel and nickel binary alloys with silicon has been determined at temperatures between 1500°C and 1650°C using quartz crucibles in order to investigate the deoxidation of nickel based alloys. The equilibrium constant of the deoxidation reaction in liquid nickel and the effects of the different alloying elements such as chromium, molybdenum, tungsten, iron, cobalt and coppcr on the activity coefficient of oxygen in liquid nickel have been established.

Jan 1, 1993

By M Sciortino, J Korczak, J Muinonen, A St-Jean

The Dumont deposit is a large (1179 Mt reserve), low-grade (0.27 per cent nickel) nickel sulfide project located in the Abitibi region 25 km west of Amos, Quebec. Royal Nickel Corporation (RNC) acquired the project in 2007 and has since taken the deposit through to feasibility. The disseminated nickel sulfide and alloy mineralisation is hosted within the serpentinised dunite subzone of the Dumont Sill; a differentiated, pervasively serpentinised, ultramafic sill of komatiitic affinity. Pentlandite ((Ni,Fe)9S8), heazlewoodite (Ni3S2) and awaruite (Ni2.5Fe) are the dominant nickel-bearing metallic phases and can be recovered by conventional methods (flotation, magnetic separation). Non-recoverable nickel is also present within serpentine and olivine of the silicate matrix.A detailed mineralogical program including 1420 QEMSCAN« samples and 4400 electron microprobe points was undertaken to increase the understanding of the nickel deportment in the various recoverable and non-recoverable phases in a spatial context across the deposit. A total of 105 metallurgical tests have been performed under a standard procedure which have linked the mineralogy to metallurgical performance. This has allowed the creation and modelling of geometallurgical domains on a block-by-block basis to understand the recovery variation and metallurgical performance throughout the deposit. Understanding the spatial variability of Ni deportment in recoverable and non-recoverable phases through mineralogy is the key to understanding metallurgical performance, thus unlocking the value of the Dumont deposit and other large tonnage low-grade ultramafic nickel deposits.CITATION:Sciortino, M, Muinonen, J, Korczak, J and St-Jean, A, 2013. Geometallurgical modelling of the Dumont Deposit, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 93-100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By I. Yochev, A. A. Metelev, A. I. Stepanenko, A. P. Purgin, M. G. Viduetsky, A. M. Panshin, I. F. Garifulin

"Pneumatic flotation cells of the KFM series are intended for the concentration of various ores and technogenic materials. The key operating principle of the flotation cells of the KFM series is the preparation of pulp for flotation in blowers, offering the advantage of an accelerated flotation process. This report summarizes the results of the implementation and operation of the KFM cells at Russian and foreign projects in 2015-2017. Their implementation and operation experience confirms the high efficiency of the KFM cells, especially in the head of lead and zinc, copper and zinc, copper flotation processes:head KFM-600 flotation cell recovers from lead-zinc ore (Rudmetal AD modular concentrator) up to 52% of lead in a single stage (without cleaner flotation) in a salable lead head concentrate (grade of up to 76% lead, 2.3% zinc). The flotation cell proved to be much more efficient than originally expected in the process description in the design phase,flotation of the copper-zinc ore from Novo-Shemur deposit (PJSC Svyatogor concentrator) in two KFM- 1400M cells recovers up to 65% of copper and 70% of zinc in a high-grade bulk copper-zinc concentrate containing 12-13% of copper and 25-28% of zinc. The installation of the two cells with a combined capacity of 26 m3 allowed to decommission 4 chambers of FPM-16 pneumomechanical flotation cells with a combined capacity of 64 m3 with a simultaneous increase in the overall ore concentration performancea single KFM-1400M cell (13 m3) recovers from the copper ore from Volkov deposit (PJSC Svyatogor concentrator) 53% of copper into a high-grade copper head concentrate (33.0% of copper). For comparison, the pneumomechanical cell FPM-16 (capacity 16 m3) has almost half as low copper recovery (29.6%) into the head concentrate at a lower grade (30.5% copper)."

Jan 1, 2018

By J Lombardi, M Weidenbach

"OZ MineralsÆ Prominent Hill copper-gold concentrator is located 650 km north-east of Adelaide, 130 km north-east of BHP BillitonÆs Olympic Dam operation and 130 km south-east of the regional township of Coober Pedy, in the Gawler Craton region of South Australia. The concentrator was built in 2008 and commenced commercial production in early 2009. The Prominent Hill concentrator is comprised of a conventional grinding and flotation processing plant with a 10 Mt/a ore throughput capacity, operating well over the design rate of 8 Mt/a. Increased throughput rates have seen a decreased water recovery from the tailing thickener due to operating above design. Subsequently, greater pressure was placed on the site water balance and bore field off-take rates due to increased evaporation losses from greater volumes of water reporting to the tailing storage facility. This resulted in a trade-off between water availability and milling rates as part of the operating strategy.Two projects were implemented to increase the tailing thickener underflow density, thus improving water recovery directly back into the operating plant, reducing water losses via evaporation and decreasing the reliance on the bore field system operating at maximum rates to maintain mill throughput. The two projects were: tailing thickener feedwell redesign implementation of the Manta Cube control system.This paper discusses the background, implementation and benefits attained from these two key projects. Combined they have allowed a two to three per cent increase in tailing thickener underflow density to be consistently achieved, which has allowed greater water recovery. As a result, the processing plant has been able to operate at higher throughput rates when required, with greater water availability in the process plant recirculating system and a reduction in occurrences of the plant being æslowed downÆ due to water supply shortfalls. Both projects have also delivered a significant reduction in flocculant usage.CITATION:Weidenbach, M and Lombardi, J, 2012. Tailing thickener operability and control improvements at Prominent Hill, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 137-142 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 29, 2012

By Zhiqiang Zhou, Libin Zhu, Zizong Zhu, Hao Xiong, Yuchuan Ding

In order to utilize the lean ore resources from XinJiang rationally and optimize mixture, laborarory measurements have been carried out under different basicity, various mixed carbon content as well as the properties (ratio) of fuel particle size by the sintering pot for further microstructure analyses. The results show that sinter strength falls by 5.0%, low temperature reduction disintegration index (RDI) drops off to the lowest in certain ranges. The natural degradation index of sinter is much higher when sinter basicity is between 1.65 and 1.75. The sinter strength increases when sinter basicity is between 1.75 and 2.0. Meanwhile, the sinter strength and RDI +3.15 improve with increasing carbon content. And the sinter strength and RDI+3.15 both decrease with the decrease of the distribution ratio of small fuel particle, thereby decreases the yield of sinter. Microstructural analyses have been investigated to figure out the mechanism of the influence of the three factors on sinter.

Mar 1, 2017

By Earl L. Rau

At the present time, whether an electric utility uses high-sulfur coal is largely determined by geographical location, clean air legislation, and the age of the power plant. Acid rain legislation may well be the new force to change the use of high-sulfur coal. A number of coal papers were presented at the SME Fall Meeting in St. Louis, MO, Sept. 1986. These papers discussed high-sulfur coal in relation to its economics, trends and prospects, value of cleaned coal, and coal-cleaning technology. The Clean Air Act of 1970 required the reduction of SO, emissions from most stationary electric-generating plant to 0.5 kg (1.2 lbs) SO2, per million Btu of heat input. It was possible for many plants to utilize lower-sulfur coal or a mixture of high-sulfur and low-sulfur coal to meet this emission requirement. This 1970 act greatly increased the use of low-sulfur western coal. The 1978 amendment to the Clean Air Act required all new plants to use Flue Gas Desulfurization (FGD) to meet a requirement of 70% reduction of potential SO2 emissions to 0.3 kg (0.6 lb) SO2 per million Btu of heat input. With the requirement to use FGD, there was little or no demand for low-sulfur western coal in new eastern power plants. If' new acid rain legislation is enacted, it likely will require sizeable reductions in SO2, emissions by existing coal users. There might then be a shift to greater use of low-sulfur coals. The low-sulfur coals could come from either western or eastern mines or from cleaned eastern coals. Economics will dictate the approach older power plants will take to meet new regulationsuse FGD or low-sulfur coal. Coal use for electric power generation has changed from 1970 to 1985. Table 1, (Land, preprint 86-333) shows the change. The table shows that in 1985, US utilities used about 255 Mt (280 million st) of high-sulfur coal. Some 45 to 54 Mt (50 to 60 million st) of high-sulfur coal is being used in plants equipped with FGD and most of this use is in eastern states. This leaves 200 to 209 Mt/a (220 to 230 million st) of high-sulfur coal being used without FGD treatment. These plants are at risk if acid rain legislation is passed. Most of these plants are in the east and are more difficult to supply with low-sulfur coal. Estimates range from $20 to $30 billion capital investment and from $5 to $9 billion dollars per year operating costs to reduce SO2, emissions from those old medium-to-high-sulfur coal-burning plants. G. W. Land, (preprint 86-333), also presents tables relating to power generating costs and coal types. The author's tables are extracted from Land's tables IV and V. Table 2 here presents costs for a new plant. This includes the impact of different heat rates, fuel costs, fuel qualities, operating and maintenance costs, labor costs, and waste disposal costs. Table 3 compares estimated costs to retrofit an older plant with a limestone scrubber versus switching the same plant to low-sulfur eastern or western coal. Costs of switching include upgrading the electrostatic precipitator and - with western coal - costs of derating. Bhagwat, (preprint 86-325), details the trends in high-sulfur coal markets from 1974 to 1984. He also gives some prospects for high-sulfur coal markets, 1984 to 1994. The prospect depends mostly on whether acid rain legislation is enacted. By 1994, if New Source Performance Standards (NSPS) continue to be applied, high-sulfur coal demand from six mid-west and eastern states is expected to increase by 27 Mt (30 million st). • L. A. Khan and J. W. Baxter, (preprint 86-373), discuss several coal cleaning technologies such as froth flotation of fines, bulk oil separation and oil agglomeration, oil agglomeration/flotation, and air-floc flotation. ? (Space limitations preclude listing references. A complete list is available from the author.)

Jan 1, 1987

By Damon P. Vandermaat

Coupon testing allows for the rapid understanding of a material?s likely behavior in service conditions, allowing engineers and operators to make informed decisions about the likely service-life of parts when subjected to field conditions. Bend testing has been identified as the best approach for exploring rock bolt susceptibility to stress corrosion cracking (SCC) in underground mining. The bend test specimens used were 2?3 mm thick slivers of steel, cut from the outer edge of a rock bolt. For the specimens, 1350 grade steel was chosen due to its wide use in the industry. The jigs themselves are small assemblies made of stainless steel that are capable of imparting a bending load on the specimens. The jigs were installed at a coal mine located in the Western Coals West of Sydney, Australia, in such a way as to expose the test specimen to water dripping from the mine roof. It is expected that this approach will yield results pointing to the likely SCC mechanisms affecting the service life of rock bolts, as well as demonstrate the jigs? usefulness as an early warning system for SCC. Furthermore, the coupon tests will be correlated against the results of large-scale laboratory tests.

Jan 1, 2012

By Nagy El-Kaddah

One of the emerging technologies for the production of ultra-clean metals is electromagnetic filtration. The theory and the mechanism of electromagnetic separation of inclusions from molten metal are briefly reviewed along with basic electromagnetic separation systems. This paper focuses on inclusion removal in the induced current separators, with specific reference to a new separator developed at the University of Alabama. A simple analytical model is presented for the analysis of particle separation in such a system. The role of the applied magnetic field on inclusion removal will be discussed. It is shown that particle velocity increases exponentially with increasing magnetic field strength. At moderate field strengths, the velocity of 50 to 100µ inclusions are an order of magnitude larger than those achieved by buoyancy. The separator developed at the University of Alabama is described together with experimental results of laboratory and large scale experiments on purification of molten aluminum. These results demonstrate ?the capability of the system for producing super-clean metals.

Jan 1, 1996

By William B. Hetherington

Communities are the foundation upon which the whole structure of society rests and upon which the nation builds its hope for the future. They are not established to serve any one particular generation, nor any one element or group, but should be erected to render a lasting service to all who are to follow. They play a very vital and important role in the lives and welfare of the people, in their industrial, business, and social relations, and in the economy of the nation, of which they are the fundamental assets. Communities and civic governments are destined to be vital factors in the national welfare in the days that are to come. Any improvement in national or world conditions must have its origin within the communities. Any attempt at solution of the community problem must give some consideration to the fundamental elements which exist in every community, and to the underlying principles, and ways of life and thought, upon which community life is based. The community is, in its essence, a number of people living and working more or less closely together, sharing common rights, privileges, conveniences, and comforts, which would be impossible for the individual to obtain for himself by his own efforts alone, or in any other way than by the mutual exchange of persona! services and resources. In this way, men have increased the returns from their labour and commerce, have raised the standard of their living, with better social, educational, and recreational facilities, and enjoy a greater personal security.

Jan 1, 1943

By Christopher Bambridge

The Washington State Department of Transportation (WSDOT) is constructing a new tunneled route under Seattle to replace the existing State Route 99, Alaskan Way Viaduct (AWV), which follows the historic waterfront for several miles. The viaduct separates the businesses that rely upon the tourist trade from the down-town area. The reconnection of the city to the waterfront areas will occur following the completion of the SR99 Re-placement program that replaces the aging structure that was severely impacted by the 2001 Nisqually earthquake, with a state-of-the-art, twin-deck highway with a world record-breaking 17.4-m (57.3-ft) bored tunnel. Constructed in the 1950s, the double-tiered viaduct is nearly 3.2 km (2 miles) long and runs parallel to city?s waterfront. The viaduct, which is partially supported by the seawall, is a vital local and regional transportation link and carries about 110,000 vehicles each day. The seawall, built from concrete and timber in the 1930s, extends along Seattle?s waterfront and supports the soil behind it. Studies in the 1990s showed that the viaduct was nearing the end of its useful life, apparent by its exposed rebar and weakened columns. The 2001 Nisqually earth-quake further damaged the viaduct, forcing WSDOT to temporarily close it for inspection and limited repairs. The viaduct and nearby seawall are vulnerable to an-other earthquake and continue to show signs of age and deterioration. Following a collaborative process, WSDOT developed the following guiding principles to the viaduct replace-ment:

Sep 1, 2013

By Ki Bui Ma

Momentum wheels with superconducting bearings can integrate both attitude control and energy storage functions, with attendant savings in the total volume and weight of hardware, and power consumption, all of which are in short supply on mini-satellites. We have built and tested a prototype with a wheel of mass 1.9 kg, diameter 3.25 in, and height 3 in, which can store 3.5 J-sec of angular momentum and 5 kJ of energy when it rotates at an angular speed of 15000 RPM. The energy density of 2.5 kJ/kg achieved is comparable with the lower range for lead-acid batteries. To show that the wheel is energy efficient, we have performed spin down tests and measured the input power required to sustain rotational speed. Results indicate that power consumption, even accounting for the needs of cooling system, is significantly smaller than that for state of the art commercial reaction wheels.

Jan 1, 2002

By R. Miller

Lowering our globe’s emissions is a major effort as we move toward a future net-zero carbon environment requiring significant investment in a new, low-carbon infrastructure, along with key market incentives to change. Industry will play a key part in this transformation, requiring expertise in both energy and emissions. Key elements of the de-carbonization strategy are: energy data, emissions reporting method, governance, de-carbonization project generation and drivers, the MACC, electrification, and the de-carbonization checklist. For a zero carbon future, it will be key for business leaders to understand decarbonization, anticipate technological changes, and implement new business me

Mar 2, 2022