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Other work includes z-pinches to produce soft x-rays and also plans to use gas puff pinches as closing and opening switches, utilizing magnetohydrodynamic (MHD) instabilities for the opening phase. They have numerous applications in mind for the ASOI and II machines and have, for instance, demonstrated their use to drive a virtual cathode oscillator (Vircator) to produce 100-ns pulses of 1- to 6-GHz microwaves. This is the most compact overall Vircator system that I have seen in either the United States or Russia. At the present time they are conducting feasibility studies for the use of these machines to make a free electron laser (FEL).

In cooperation with the National Institute for Fusion Studies at Nagoya, they are investigating the feasibility of using a rail gun to accelerate hydrogen

ice pellets for injection into and refueling of fusion plasmas. The acceleration force in a conventional rail gun is proportional to the product of the current and the self-induced magnetic field. By applying an external, permanent magnetic field of 1 T they hope to reduce the required rail current and thereby the rail erosion and the resulting impurity injection into the fusion plasma. The goal is a velocity in excess of 3 km/s for a 0.3-g mass in a 1-meterlong rail gun. A similar effort at Mitsubishi Heavy Industries, Ltd. is described in the next section of this report.

Much work is also underway on gas discharge phenomena. This includes dc glow discharges in flowing gas systems for laser excitation and plasma processing. Another effort of great personal interest is the work on pulsed

arc discharge resistance measurement. This is the primary area of our recent cooperation and is a very difficult measurement of importance to developing low loss, high repetition rate spark gap switches. A "hobby" experiment of Dr. Akiyama is an effort to trigger lightening discharges using long water spouts. Some very interesting and unexplained laboratory results have been obtained so far.

All in all, this is a very productive university research group with lots of ideas and experiments and they seem to have a great deal of fun doing it.

A surprise to me was the visit to the High Energy Rate Laboratory at Kumamoto University (Dr. T. Mashimo). This laboratory has facilities for doing explosives work and high velocity powder gun experiments on campus. I am only aware of two universities with such facilities in the United States and these are rather remotely located. An interesting concept also being studied here is a high velocity centrifuging experiment to produce new materials by sedimentation in condensed matter. The process is apparently proprietary and could not be discussed in detail. A paper by Dr. Mashimo [in Phys. Rev. A 38, 4149 (1988)] gives some of the background theory.

Mitsubishi Heavy Industries, Ltd., Takasago Research and Development Center

Drs. S. Kuribayashi, K. Asada, and K. Azuma were my hosts. This is again a large research center that is part of a very large corporation. The work at the center covers a wide range of topics, such as breeder reactors, fusion reactors, robots, turbomachinery, environmental control, space technology, control technology, and manufacturing technology. The center is part of the U.S.-Japan cooperative program on a tritium system test assembly. I visited the Applied Physics Team, where

Dr. Y. Matsumoto is the director; unfortunately, he was absent.

more as a user of these devices for ACKNOWLEDGMENT
shock physics and impact studies
rather than in the devices themselves
which, except for the ice pellet injector,
were rather conventional in design and
results.

Other work of interest in this group
includes the development of large CO
lasers for metal cutting. They now have
a 10-kW unit and plan to go to 20 kW
for cutting stainless steel plates up to
30 cm thick. This would have applica-
tion to the disassembly of old pres-
surized water nuclear reactors. Studies
are underway on a free electron laser
in the infrared regime using a 70-MeV
accelerator. Work is also in progress
on ion thrusters for space propulsion.

The team also is working on a rail gun system for hydrogen ice pellet injection in fusion plasmas (see the previous section). They want to accelerate 3-mm-diameter, 3-mm-long ice pellets, but they are presently experimenting with plastic projectiles. A novel aspect was the use of a laser to ignite the rail gun discharge in an effort to increase reliability and life of the device. The system is intended for use on the JT-60 Tokamak. The results, so far, are inconclusive. They want to use yttrium oxide doped tungsten in the rails to decrease the work function and hence the erosion and injected impurities. The current level is approximately 20 kA, and they use an injection velocity of SUMMARY 300 m/s to obtain a maximum velocity of 2.3 km/s. They cooperate with Professor A. Sawaoka at the Tokyo Institute of Technology on this work.

A conventional, square bore rail gun with no preinjection velocity is driven by a 250-kJ, 20-kV capacitor bank via an 8:1 transformer to get 1 MA current. The gun is disassembled after about 10 shots. The exit velocity for a 1-cm by 1-cm, 4-g projectile is about 3 km/s. This is a "university size" experiment, similar to one in our own laboratory (actually somewhat smaller than ours).

A 50-kJ electrothermal gun with capillary discharge accelerates 1-g projectiles to 1 km/s, but they have severe problems (as do others) with radially induced stress cracking in the insulator. Their next plan is for a 500-kJ electrothermal gun accelerating 10-g projectiles to 3 km/s and then hopefully on to a 1-MJ experiment. They claim to have excellent computer codes for projectile impact studies that they compare with their experimental results. Their interest at this time, unless the Japanese Defense Force initiates a new program, seems to me

After several visits to Japan over the past 15 years, I remain both surprised and impressed by both the quantity and quality of pulsed power research and development in Japan. In the United States this line of work has mostly been supported by the Department of Defense or the nuclear weapons side of the Department of Energy and similarly in the United Kingdom and Russia. This is obviously not the driving forces behind the work in Japan, and I remain somewhat puzzled as to the driving force and motivation behind the Japanese work. We are all, obviously, looking very hard for industrial applications, but these have been very slow to develop. A particular surprise to me was the proliferation of and interest in electromagnetic launchers. Time did not permit me to visit all these EML facilities (e.g., Japan Steel Works has its facilities at Hokkaido), but I would like very much to make another visit to Japan devoted primarily to EML facilities. Cooperative efforts in this field could prove to be very fruitful.

I want to thank Professor Hidenori Akiyama of Kumamoto University and Dr. Kazunari Ikuta of Japan Steel Works, Ltd., who were instrumental in organizing my lectures and visits and arranging for helpful and competent guides at all places. Travel support from the Office of Naval Research is greatly appreciated.

M. Kristiansen received B.S.E.E., and Ph.D. degrees from the University of Texas at Austin in 1961 and 1967, respectively. Since 1966 he has been on the faculty of Texas Tech University, Lubbock, where he is now the C.B. Thornton/P.W. Horn Professor of Electrical Engineering/Physics. His current research interests and specialties are plasma dynamics, pulsed power technology, and quantum electronics. He has published over 200 journal articles and conference proceedings papers, has coauthored one book, and is coeditor of a new series of books on Advances in Pulsed Power Technology. Dr. Kristiansen is a member of the Institute of Electrical and Electronics Engineers (IEEE) (Fellow), the American Society for Engineering Education, the American Physical Society (Fellow), and the American Association for the Advancement of Science. He has received the following awards: U.S. Department of the Air Force Meritorious Civilian Service Award (1985), IEEE International Pulsed Power Conference Peter Haas Award (1987), and IEEE Nuclear and Plasma Science Society Merit Award (1991).

THE FIRST ASIA-PACIFIC CONFERENCE ON ALGAL BIOTECHNOLOGY

This article presents recent research in three major areas of algal biotechnology:
large sea weeds, their products, and methods of cultivation; technologies for
cultivating microalgae and the products of these algae; and use of algal
technologies for solving ecological and environmental problems.

INTRODUCTION

by Aharon Gibor

environmental problems. There were 45 oral and 30 poster presentations on these topics.

The first Asia-Pacific Conference on Algal Biotechnology was held from 29-31 January 1992 at the Institute for SEA WEEDS Advanced Studies of the University of Malaysia, Kuala Lumpur. The meeting was sponsored by the university, the Malaysia National Working Group on Biotechnology, and the Ministry of Science, Technology, and Environment.

There were 151 scientists from 25 countries, with the majority of these from Southeast Asia--Malaysia, Indonesia, India, China, Thailand, Singapore, and the Philippines. The remainder of the delegates came from Australia, Japan, Taiwan, Hong Kong, Sri Lanka, the United States, New Zealand, Kuwait, the United Kingdom, Sweden, Italy, Morocco, and France. The participants were from academic institutions, governmental organizations, and private companies. It was very interesting to discover the growing interest in so many countries in using algae for a variety of purposes.

Three major topics in algal biotechnology were considered: (1) large sea weeds, their products, and methods of cultivation; (2) technologies for cultivating microalgae and the products of these algae; and (3) use of algal technologies for solving ecological and

Prof. Isabella A. Abbott (University of Hawaii), the doyenne of Pacific algal taxonomy, introduced the first session. She emphasized the value of identifying the algal species and strains because of variations in the quality of their chemical constituents. For example, the quality of agar that is obtained from different strains of agarophyte differs greatly. Screening, selecting, and propagating desired plants, therefore, are important steps before mariculture can be undertaken.

Dr. Gavino C. Trono (Philippines) substantiated Abbott's points by the work in progress in the Philippines on sea weed mariculture. The important species being cultivated are Eucheuma, Kappaphycus, Gracilaria, and Caulerpa. It is projected that up to 1 million people will be employed in the mariculture and processing of these sea weeds within 2 years.

The introduction of sea weed colloids as fat substitutes in hamburgers is anticipated to create a demand for these substances. In the Philippines the economic importance of sea weeds has already surpassed that of coconut plantations.

One of the problems being studied is the choice of strains that will withstand fluctuations in the salinity of the culture medium. Shallow seawater ponds become diluted during the rainy season and concentrated during dry spells; this is deleterious to some strains of algae. Strains that are tolerant to salinity variation will be of great advantage in such cultures.

The quality of the biocolloids being produced varies greatly with the strains being used and also with the culture conditions, such as temperature, availability of nutrients, age of the plants, and the parts of the plants that are extracted. Most of the farming is being done by vegetative propagation of branches of the algae either suspended from nets or planted in the bottom mud of shallow ponds.

An important problem is ice-ice disease, which attacks Eucheuma plants. The primary cause is still not known and is under investigation.

Peter Gracesa et al. (United Kingdom) presented systematic studies on agarophytic algae based on the analysis of 18S-ribosomal RNA genes. Small pieces of dried algal tissue are sufficient for DNA extraction, polymerase chain reaction (PCR) amplification, and analysis.

Other reports on sea weeds covered their lipids, heavy metal ion uptake, the quality of the biocolloid of red and brown algae, and a demonstration of antibiotics in sea weed extracts.

TECHNOLOGIES FOR CULTIVATING MICROALGAE AND THE PRODUCTS OF THESE ALGAE

M.A. Borowitzka (Murdoch University, Australia) introduced the topic by reviewing the variety of products already being derived from algal cultures. Dunaliella is being cultured for its beta carotene content and, along with Spirulina, it is being produced on a commercial scale in Australia, Italy, Israel, and the United States. Haematococcus produces astaxanthin. Porphyridium is grown for phycobilins and for biocolloids. Other algae contain hydrocarbons, fatty acids, and other bioactive substances.

A major problem in the large scale farming of unicellular algae is the control of competing organisms. Dunaliella has the unique advantage of the ability to grow in high salinity media where competitors are inhibited.

A number of diatoms and dinoflagellates are being cultivated primarily to serve as food in aquaculture hatcheries. Some larvae of highly valued invertebrate animals require specific algae for their normal development.

The recent interest in highly unsaturated fatty acids for human nutrition has led to studies on cultivation of some diatoms and other algae. Many of these cultures are being done not in open ponds but in closed culture chambers. New designs of such "photo bioreactors" were reported. Closed transparent tubular systems appear to be popular; both horizontal and vertically held tubular systems were described. These types of bioreactors are expensive and are therefore suitable for the production of very highly valued substances.

A number of reports on culture conditions that maximize the yield of products such as carotenoid pigments or unsaturated fatty acids were presented.

A major problem applicable to unicellular algae and not to filamentous forms such as Spirulina is the harvesting of the crop from a dilute aqueous suspension. Flocculation, filtration, and centrifugation are the common procedures being studied.

THE USE OF ALGAE FOR SOLVING ECOLOGICAL AND ENVIRONMENTAL PROBLEMS

The last topic was introduced by B. Whitton (University of Durham, United Kingdom). The ability of some algae to concentrate ions from the environment has led to their use as pollution detectors, especially of heavy metals. Both planktonic and benthic algae from marine and freshwater were shown to be able to accumulate some metals. Research on the most appropriate species for detecting specific elements is being conducted. In another aspect based on these properties of the algae, the species composition of the algae in a body of water functions as an indicator of the chemical composition of the water. The algal composition blooming in effluents from different mines or from ore containing soil is said to be unique for the specific metal ions that are present. Mass cultures of such metal concentrating algae are being considered for the detoxification of industrial effluents.

Whitton also indicated that microanalysis of small samples of dried algae indicated the presence of specific metals in their environment. Dried and stored herbarium specimens can, therefore, serve as good records of environmental conditions at the time of their collection and can be used for comparison to the present state of the water.

Cladophora and Enteromorpha are among the recommended algae for evaluation of heavy metal contamination of estuaries.

The use of algae in oxidation ponds to decompose organic pollution in industrial, farm, and domestic waste waters is an active area of research. The treatment of effluents from palm oil mills and rubber treatment plants in Malaysia is being studied. In all these studies a major goal is the recovery of purified water. A remaining problem is finding an economical method for harvesting the produced algal biomass; otherwise, the procedure just substitutes an algal biomass for the previous organic waste materials.

Another aspect of algal cultivation is encouraging the growth of nitrogenfixing algae in farm fields. The productivity of rice fields was shown to increase in the presence of such algae. The control of noxious algae in drinking water sources is another subject of interest to environmental public health officials.

SUMMARY

Most of the reports dealt with subjects that are not new, but their application to local problems was interesting. Commercial sea weed aquaculture in this region is less than 20 years old, but it is fast growing and already significant to the economy of the Philippines. Indonesia, Thailand, and Malaysia also are rapidly developing this resource. The availability of sunshine, water, and manpower makes the region suitable for cultivating algae. The interest and enthusiasm among the young scientists from Southeast Asia who attended this conference indicate that this is indeed a growing enterprise. It reflects the general spirit of this rapidly growing region. With the development of new markets for algal biocolloids, I foresee rapid development of this area of marine biotechnology in the near future.

For more information on this conference, please contact the organizer:

Dr. Phang Siew Moi

Institute for Advanced Studies
University of Malaysia

59100 Kuala Lumpur

Aharon Gibor completed a 1-year assignment at the Office of Naval Research Asian Office in September 1990. Dr. Gibor is a professor of biology at the University of California, Santa Barbara. He received a B.A. degree in 1950, his M.A. degree in 1952 from the University of California, Berkeley, and his Ph.D. degree in 1956 from Stanford University. His thesis research was done at the Hopkins Marine Station. Dr. Gibor was involved in research on the genetic autonomy of cytoplasmic organelles of eukaryotic cells, especially chloroplasts and flagella. His present research is on the growth and development of algal cells and tissues and the role of cell walls of these plants in controlling their development.

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