Shigehiro Nishijima

Superconducting high gradient magnetic separation for purification of wastewater from paper factory

High gradient magnetic separation (HGMS) can be one of the promising ways for a new environmental purification technique because of producing no contamination such as flocculants and having possibility of treating large amount of wasted water within a short time. The magnetic separation system for purification of wastewater from the paper factory has been developed. The test plant of 2000 ton/day was set up in the actual paper manufacturing process and a purification test of the wastewater was performed. The magnetic seeding of the organic pulp and dyes were successfully performed and the Chemical Oxygen Demand (COD) value for recycling was reached to less than 40 ppm after magnetic separation. The superconducting magnet for the system is 3 T, 680 mm long and 400 mm bore NbTi solenoid. The system mainly consists of a mixing tank (magnetic seeding tank), a settling tank, and a superconducting magnet. Floating magnetic flocks composed of magnetite particles and organic polymers such as pulp and dye are captured by magnetic force in the superconducting magnet chamber. Some magnetic flocks are precipitated at the settling tank by the gravity, which helps to reduce the amount of magnetic flocks going through the magnet chamber. The system has been successfully operated for several months

Superconductivity and the environment: a Roadmap

There is universal agreement between the United Nations and governments from the richest to the poorest nations that humanity faces unprecedented global challenges relating to sustainable energy, clean water, low-emission transportation, coping with climate change and natural disasters, and reclaiming use of land. We have invited researchers from a range of eclectic research areas to provide a Roadmap of how superconducting technologies could address these major challenges confronting humanity.Superconductivity has, over the century since its discovery by Kamerlingh Onnes in 1911, promised to provide solutions to many challenges. So far, most superconducting technologies are esoteric systems that are used in laboratories and hospitals. Large science projects have long appreciated the ability of superconductivity to efficiently create high magnetic fields that are otherwise very costly to achieve with ordinary materials. The most successful applications outside of large science are high-field magnets for magnetic resonance imaging, laboratory magnetometers for mineral and materials characterization, filters for mobile communications, and magnetoencephalography for understanding the human brain.The stage is now set for superconductivity to make more general contributions. Humanity uses practically unthinkable amounts of energy to drive our modern way of life. Overall, global power usage has been predicted to almost double from 16.5 to 30?TW in the next four decades (2011 Equinox Summit: Energy 2030 http://wgsi.org/publications-resources).The economy with which electrons carry energy compels the continued quest for efficient superconducting power generation, energy storage, and power transmission. The growing global population requires new arable land and treatment of water, especially in remote areas, and superconductivity offers unique solutions to these problems. Exquisite detectors give warning of changes that are otherwise invisible. Prediction of climate and disasters will be helped by future supercomputer technologies that support huge amounts of data and sophisticated modeling, and with the aid of superconductivity these systems might not require the energy of a large city.We present different sections on applications that could address (or are addressing) a range of environmental issues. The Roadmap covers water purification, power distribution and storage, low-environmental impact transport, environmental sensing (particularly for the removal of unexploded munitions), monitoring the Earth?s magnetic fields for earthquakes and major solar activity, and, finally, developing a petaflop supercomputer that only requires 3% of the current supercomputer power provision while being 50 times faster.Access to fresh water. With only 2.5% of the water on Earth being fresh and climate change modeling forecasting that many areas will become drier, the ability to recycle water and achieve compact water recycling systems for sewage or ground water treatment is critical. The first section (by Nishijima) points to the potential of superconducting magnetic separation to enable water recycling and reuse.Energy. The Equinox Summit held in Waterloo Canada 2011?(2011 Equinox Summit: Energy 2030 http://wgsi.org/publications-resources) identified electricity use as humanity?s largest contributor to greenhouse gas emissions. Our appetite for electricity is growing faster than for any other form of energy. The communiqu? from the summit said ?Transforming the ways we generate, distribute and store electricity is among the most pressing challenges facing society today?. If we want to stabilize CO2 levels in our atmosphere at 550 parts per million, all of that growth needs to be met by non-carbon forms of energy? (2011 Equinox Summit: Energy 2030 http://wgsi.org/publications-resources). Superconducting technologies can provide the energy efficiencies to achieve, in the European Union alone, 33?65% of the required reduction in greenhouse gas emissions according to the Kyoto Protocol (Hartikainen et?al 2003 Supercond. Sci. Technol. 16 963). New technologies would include superconducting energy storage systems to effectively store power generation from renewable sources as well as high-temperature superconducting systems used in generators, transformers and synchronous motors in power stations and heavy-industry facilities. However, to be effective, these systems must be superior to conventional systems and, in reality, market penetration will occur as existing electrical machinery is written off. At current write-off rates, to achieve a 50% transfer to superconducting systems will take 20?years (Hartikainen et?al 2003 Supercond. Sci. Technol. 16 963).The Roadmap next considers dc transmission of green power with a section by Eckroad and Marian who provide an update on the development of superconducting power transmission lines in view of recent sustainability studies. The potential of magnetic energy storage is then presented by Coi and Kim, who argue that a successful transition to wind and solar power generation must be harmonized with the conventional electrical network, which requires a storage technology with a fast response and long backup times.Transport. Superconducting Maglev trains and motors for international shipping have the potential to considerably reduce the emissions that contribute to greenhouse gases while improving their economic viability by reducing losses and improving efficiencies. International shipping, alone, contributes 3% of the greenhouse gas emissions. Three sections of the Roadmap identify how high-speed rail can be a major solution to providing fast, low energy, environmentally-friendly transport enabling reduction in automobile and aircraft travel by offering an alternative that is very competitive. With maritime international environmental regulations tightening, HTS motors with the characteristics of high torque and compactness will become important devices for high-performance and low-emission electric ship propulsion systems. A section on the development of a megawatt-class superconducting motor for ship propulsion is presented by Umemoto.Monitoring in manufacturing for waste reduction. Environmental impact from the waste created by the manufacturing sector and the need to make manufacturing efficient can be addressed by terahertz imaging. This technology has great potential in non-destructive testing, industrial process monitoring and control to greatly improve the industry process efficiency and reliability by reducing waste materials and toxic by-products. The section by Du shows how terahertz imaging can provide process and property information such as rust levels under paint that can assist with the reduction of waste in manufacturing and maintenance.Monitoring for naturally occurring disturbances. The environmental and social impact of natural disasters is mounting. Febvre provides the Roadmap for the use of ultra-sensitive magnetometry to understand geomagnetic phenomena and Earth?ionosphere couplings through the study of very small variations of the magnetic field. This magnetic monitoring has many implications for understanding our environment and providing new tools for early warning of natural hazards, either on Earth or in space which will enable us to be better prepared for natural disasters.Restoring environments after military use. Throughout the world, there are many areas confirmed or suspected of being contaminated by unexploded munitions known as unexploded ordnance (UXO). Its presence is the result of wars and training of military forces. Areas affected by UXO contamination are hazardous to the public and have a major influence on the nature of land use. UXO has impact in developed as well as developing nations. For example, the USA has UXO dating back to the American Civil War and countries such as Cambodia are living with landmines as a daily issue due to more recent wars. Underwater UXO has caused severe impacts such as the explosion in 1969 in the waters of Kent in the UK that caused a reading of 4.5 on the Richter scale for earthquake monitors. Another example was a land-based detonation of a 500?kg World War II bomb in Germany killing three people in 2010. There is countless UXO from recent conflicts worldwide. Detection and accurate location with 100% reliability is required to return land to safe civilian use. Keenan provides details of a prototype magnetic gradiometer developed for this purpose.Reducing power needs for high-end IT. Supercomputers are so large that they are close to requiring their own small power plant to support the energy needed to run the computer. For example, in 2011 Facebook data centers and operations used 532 million kW hours of energy. Mukhanov explores the potential of reducing the power dissipation for future supercomputers from more than 500?MW for Exascale systems to 0.2?MW by using superconducting-ferromagnetic Josephson junctions for magnetic memory and programmable logic.Clearly superconductivity is an ultimate energy-saving technology, and its practical implementation will contribute to the reduction of CO2 emissions, improved water purification, reduction of waste and timely preparedness for natural disasters or significant events. This Roadmap shows how the application of superconducting technologies will have a significant impact when they are adopted.

Effects of coupling agents on the mechanical properties improvement of the TiO2 reinforced epoxy system

Abstract A study was carried out to investigate the effects of different coupling agents on the mechanical properties of the TiO 2 particulate filled epoxy composite. Composites prepared by dispersing TiO 2 coated with a silane coupling agent were compared with titanate coupling agent coated TiO 2 dispersed composites. Youngs modulus and flexural strength of titanate coupling agent treated composites were significantly improved compared to silane coupling agent treated composites. It was suggested that a strong interfacial bonding between the filler and the matrix existed when the titanate coupling agent was used and was explained by the adhesion model. Scanning electron microscopy studies revealed a better dispersion of surface modified filler particles and a strong adhesion/bonding between the filler and the matrix.

Fracture behavior and fracture toughness of particulate filled epoxy composites

Abstract Fracture toughness for an epoxy-TiO 2 composite system was evaluated at room and liquid N 2 temperature in which both the volume and the particle size of dispersoid have been changed. Fracture toughness was significantly increased by choosing the larger particle size of the dispersed second phase and low temperature testing environment. The relationship between the fracture toughness and the fracture surface appearance of the composites has been investigated using a linear elastic fracture mechanics approach.

Recycling of abrasives from wasted slurry by superconducting magnetic separation

Abrasives have been recovered from the slurry wasted of the factory where the silicon wafers for solar battery are processed. The slurry consists of oil and abrasives and is used in the wire saw. The viscosity of the slurry is carefully controlled to maintain a high cutting performance though it tends to be high as the silicon powder is accumulated in the slurry. The cutting performance of the slurry decreases as the amount of the silicon powder increases. The abrasives, however, still have enough performance to cut the silicon wafers. Iron segments of the wire saw were found to attach to the SiC abrasives. The iron segments magnetize the abrasives in the mechanochemical process and thus reduce the cutting performance of the abrasives. Due to the iron segments presence the abrasives with poor cutting performance could be separated from the slurry by means of superconducting magnetic separator. After the magnetic separation a centrifugal separator was used to separate the silicon powder. It was confirmed that the superconducting magnetic separation is applicable to this practical application.

Three Dimensional Motion Control System of Ferromagnetic Particles for Magnetically Targeted Drug Delivery Systems

The development of a 3-dimensional (3-D) navigation system of ferromagnetic particles in a flow system was performed. In order to improve the practice of using externally-applied magnetic fields for targeting the magnetic particles to a circumscribed body region, we tested the feasibility of a novel 3-D navigation system, made by applying a strong external (magnetic) field through a GdBaCuO bulk superconductor. A 3-D theoretical model is proposed and used in order to evaluate the efficiency of the navigation/retention of magnetic particles in the flow system. Furthermore, an experimental model system was made and the efficiency of a prototype system was examined. Comparisons of experimental and the corresponding calculation results were made to examine the theoretical model system

Evaluation of mechanical behavior of CFRC transverse to the fiber direction at room and cryogenic temperature

Abstract Interface behavior and mechanical properties of carbon fiber reinforced epoxy composites in the transverse to fiber direction were studied at room and liquid nitrogen temperature to investigate their applicability for cryogenic use. An attempt has been made to improve the properties of the composites by means of incorporating nano-sized Al 2 O 3 filler into the matrix. Youngs modulus and interlaminar shear strength at room temperature and the thermal contraction down to cryogenic temperature were improved significantly by the addition of Al 2 O 3 filler into the epoxy matrix.

Molecular design of an epoxy for cryogenic temperatures

The mechanical and thermal properties of several epoxy resins were measured to obtain guidelines for the molecular design of an epoxy resin for cryogenic temperatures. Two types of epoxy resin with different numbers of epoxy groups were mixed (with different mixing ratios) and cured. Fracture toughness, flexural strength and thermal contraction of the hybrid epoxy resins were measured down to cryogenic temperatures. The results suggest that epoxies with larger molecular weights between crosslinkings relaxed stress at the crack tip, even at cryogenic temperatures. Intermolecular forces and stress relaxation at the crack tip were found to be important for high fracture toughness.

A Study of Magnetic Drug Delivery System Using Bulk High Temperature Superconducting Magnet

A magnetic drug delivery system (MDDS) has been studied to navigate and/or accumulate the magnetic seeded drug at a local diseased part in the human body. The bulk high temperature superconductors (HTS) are employed to control the drug because they would produce the required magnetic fields for MDDS. The trajectory of the ferromagnetic particles in the blood vessel was calculated and the possibility of the navigation of the drug is discussed. In the experiment the HTS (GdBaCuO) which produces the magnetic field of 4.5 T at the surface, was located 25 mm apart from the Y-shaped blood vessel. The drug navigation probability to the desired direction was confirmed to be higher than 80%. A rat experiment was also performed successfully using a permanent magnet. The possible MDDS system will be discussed.

Development of Magnetic Field Control for Magnetically Targeted Drug Delivery System Using a Superconducting Magnet

We have been developing the device for magnetically targeted drug delivery system (MT-DDS), which can allow us to navigate and to accumulate the drug at the local diseased part inside the body by controlling to magnetic field strength and/or gradient generated by the superconducting magnets. In considering an application of this technique to the network of the blood vessel, a number of magnets should be placed within a small region. The magnetic field at the branching point is superimposed the fields from the magnets. The optimal arrangement of magnetic field for MT-DDS was calculated and experimental verification was made using several different sizes of Y-shaped glass tubes with multiple branching points as a model system of blood vessel. Ferromagnetic particles were injected into the Y-shape glass tube and were navigated by the magnetic field which was generated by the magnet optimally arranged based on the calculation. The ratio of the amount of the navigated ferromagnetic particle to the dosed amount was measured as magnetic navigation efficiency. It is found that experimental result of magnetic navigation efficiency agreed with the calculation results, which shows that magnetic navigation by the superconducting magnet can be a promising way for realization of MT-DDS.