Lapas attēli



arc discharge resistance measurement. This is the primary area of our recent cooperation and is a very difficult measurement of importance to devel

oping low loss, high repetition rate spark Rail

gap switches. A “hobby' experiment of Cu

Dr. Akiyama is an effort to trigger Polycarbonate

lightening discharges using long water spouts. Some very interesting and

unexplained laboratory results have been FRP

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 V-block

Kumamoto University (Dr.

T. Mashimo). This laboratory has faciliFe

ties for doing explosives work and high velocity powder gun experiments on

campus. I am only aware of two univer'13

sities with such facilities in the United

States and these are rather remotely Figure 3. Cross section of the rail gun. Adapted and reprinted with

located. An interesting concept also permission from A. Yamori et al., "Rail gun experiment (HYPAC) at ISAS,IEEE Transactions on Magnetics 27(1),

being studied here is a high velocity 120-129 (1991). © 1991 IEEE.

centrifuging experiment to produce new materials by sedimentation in condensed

matter. The process is apparently proOther work includes z-pinches to ice pellets for injection into and refuel- prietary and could not be discussed in produce soft x-rays and also plans to ing of fusion plasmas. The acceleration detail. A paper by Dr. Mashimo (in use gas puff pinches as closing and force in a conventional rail gun is pro- Phys. Rev. A 38, 4149 (1988)) gives some opening switches, utilizing magneto- portional to the product of the current of the background theory. hydrodynamic (MHD) instabilities for and the self-induced magnetic field. By the opening phase. They have numer- applying an external, permanent mag- Mitsubishi Heavy Industries, ous applications in mind for the ASOI netic field of 1 T they hope to reduce Ltd., Takasago Research and and II machines and have, for instance, the required rail current and thereby Development Center demonstrated their use to drive a vir- the rail erosion and the resulting imputual cathode oscillator (Vircator) to rity injection into the fusion plasma. Drs. S. Kuribayashi, K. Asada, and produce 100-ns pulses of 1- to 6-GHz The goal is a velocity in excess of K. Azuma were my hosts. This is again microwaves. This is the most compact 3 km/s for a 0.3-g mass in a 1-meter- a large research center that is part of a overall Vircator system that I have seen long rail gun. A similar effort at very large corporation. The work at the in either the United States or Russia. Mitsubishi Heavy Industries, Ltd. is center covers a wide range of topics, At the present time they are conduct- described in the next section of this such as breeder reactors, fusion reacing feasibility studies for the use of report.

tors, robots, turbomachinery, environthese machines to make a free electron Much work is also underway on gas mental control, space technology, laser (FEL).

discharge phenomena. This includes control technology, and manufacturIn cooperation with the National dc glow discharges in flowing gas sys- ing technology. The center is part of Institute for Fusion Studies at Nagoya, tems for laser excitation and plasma the U.S.-Japan cooperative program they are investigating the feasibility of processing. Another effort of great on a tritium system test assembly. I using a rail gun to accelerate hydrogen personal interest is the work on pulsed visited the Applied Physics Team, where Dr. Y. Matsumoto is the director, unfor- more as a user of these devices for ACKNOWLEDGMENT tunately, he was absent.


shock physics and impact studies The team also is working on a rail rather than in the devices themselves I want to thank Professor Hidenori gun system for hydrogen ice pellet which, except for the ice pellet injector, Akiyama of Kumamoto University and injection in fusion plasmas (see the were rather conventional in design and Dr. Kazunari Ikuta of Japan Steel Works, previous section). They want to accel- results.

Ltd., who were instrumental in orgaerate 3-mm-diameter, 3-mm-long ice Other work of interest in this group nizing my lectures and visits and pellets, but they are presently experi- includes the development of large CO arranging for helpful and competent menting with plastic projectiles. A novel lasers for metal cutting. They now have guides at all places. Travel support aspect was the use of a laser to ignite a 10-kW unit and plan to go to 20 kW from the Office of Naval Research is the rail gun discharge in an effort to for cutting stainless steel plates up to greatly appreciated. increase reliability and life of the device. 30 cm thick. This would have applicaThe system is intended for use on the tion to the disassembly of old pres- M Kristiansen received B.S.EE and JT-60 Tokamak. The results, so far, are surized water nuclear reactors. Studies Ph.D.degrees from the University of inconclusive. They want to use yttrium are underway on a free electron laser Texas at Austin in 1961 and 1967, oxide doped tungsten in the rails to in the infrared regime using a 70-MeV respectively. Since 1966 he has been decrease the work function and hence accelerator. Work is also in progress on the faculty of Texas Tech Univerthe erosion and injected impurities. on ion thrusters for space propulsion. sity, Lubbock, where he is now the The current level is approximately 20 kA,

C.B. Thornton/P.W. Horn Professor and they use an injection velocity of SUMMARY

of Electrical Engineering/Physics. His 300 m/s to obtain a maximum velocity

current research interests and speof 2.3 km/s. They cooperate with After several visits to Japan over cialties are plasma dynamics, pulsed Professor A. Sawaoka at the Tokyo the past 15 years, I remain both sur- power technology, and quantum Institute of Technology on this work. prised and impressed by both the quan

electronics. He has published over A conventional, square bore rail gun tity and quality of pulsed power research 200 journal articles and conference with no preinjection velocity is driven and development in Japan. In the United proceedings papers, has coauthored by a 250-kJ, 20-kV capacitor bank via States this line of work has mostly been one book, and is coeditor of a new an 8:1 transformer to get 1 MA current. supported by the Department of Defense series of books on Advances in Pukod The gun is disassembled after about or the nuclear weapons side of the Power Technology. Dr. Kristiansen 10 shots. The exit velocity for a 1-cm by Department of Energy and similarly in is a member of the Institute of Elec1-cm, 4-g projectile is about 3 km/s. the United Kingdom and Russia. This trical and Electronics Engineers This is a "university size" experiment, is obviously not the driving forces behind (IEEE) (Fellow), the American similar to one in our own laboratory the work in Japan, and I remain some- Society for Engineering Education, (actually somewhat smaller than ours). what puzzled as to the driving force the American Physical Society (Fel

A 50-kJ electrothermal gun with and motivation behind the Japanese low), and the American Association capillary discharge accelerates 1-g work. We are all, obviously, looking for the Advancement of Science. He projectiles to 1 km/s, but they have very hard for industrial applications, has received the following awards: severe problems (as do others) with but these have been very slow to develop. U.S. Department of the Air Force radially induced stress cracking in the A particular surprise to me was the Meritorious Civilian Service Award insulator. Their next plan is for a proliferation of and interest in electro- (1985), IEEE International Pulsed 500-kJ electrothermal gun accelerating magnetic launchers. Time did not permit Power Conference Peter Haas Award 10-g projectiles to 3 km/s and then me to visit all these EML facilities (e.g., (1987), and IEEE Nuclear and Plasma hopefully on to a 1-MJ experiment. Japan Steel Works has its facilities at Science Society Merit Award (1991). They claim to have excellent computer Hokkaido), but I would like very much codes for projectile impact studies that to make another visit to Japan devoted they compare with their experimental primarily to EML facilities. Cooperaresults. Their interest at this time, tive efforts in this field could prove to unless the Japanese Defense Force be very fruitful. initiates a new program, seems to me




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.

by Aharon Gibor


environmental problems. There were One of the problems being studied

45 oral and 30 poster presentations on is the choice of strains that will withThe first Asia-Pacific Conference these topics.

stand fluctuations in the salinity of the on Algal Biotechnology was held from

culture medium. Shallow seawater ponds 29-31 January 1992 at the Institute for SEA WEEDS

become diluted during the rainy seaAdvanced Studies of the University of

son and concentrated during dryspells; Malaysia, Kuala Lumpur. The meeting Prof. Isabella A. Abbott (Univer- this is deleterious to some strains of was sponsored by the university, the sity of Hawaii), the doyenne of Pacific algae. Strains that are tolerant to salinMalaysia National Working Group on algal taxonomy, introduced the first ity variation will be of great advantage Biotechnology, and the Ministry of session. She emphasized the value of in such cultures. Science, Technology, and Environment. identifying the algal species and strains The quality of the biocolloids being

There were 151 scientists from 25 because of variations in the quality of produced varies greatly with the strains countries, with the majority of these their chemical constituents. For exam- being used and also with the culture from Southeast Asia--Malaysia, ple, the quality of agar that is obtained conditions, such as temperature, availIndonesia, India, China, Thailand, from different strains of agarophyte ability of nutrients, age of the plants, Singapore, and the Philippines. The differs greatly. Screening, selecting, and and the parts of the plants that are remainder of the delegates came from propagating desired plants, therefore, extracted. Most of the farming is being Australia, Japan, Taiwan, Hong Kong, are important steps before mariculture done by vegetative propagation of Sri Lanka, the United States, New can be undertaken.

branches of the algae either suspended Zealand, Kuwait, the United Kingdom, Dr. Gavino C. Trono (Philippines) from nets or planted in the bottom Sweden, Italy, Morocco, and France. substantiated Abbott's points by the

substantiated Abbott's points by the mud of shallow ponds. The participants were from academic work in progress in the Philippines on An important problem is ice-ice institutions, governmental organiza- sea weed mariculture. The important disease, which attacks Eucheuma plants. tions, and private companies. It was species being cultivated are Eucheuma,

species being cultivated are Eucheuma, The primary cause is still not known very interesting to discover the grow- Kappaphycus, Gracilaria, and Caulerpa. and is under investigation. ing interest in so many countries in It is projected that up to 1 million Peter Gracesa et al. (United using algae for a variety of purposes. people will be employed in the mari. Kingdom) presented systematic studies

Three major topics in algal biotech- culture and processing of these sea weeds on agarophytic algae based on the nology were considered: (1) large sea within 2 years.

analysis of 18S-ribosomal RNA genes. weeds, their products, and methods of The introduction of sea weed col- Small pieces of dried algal tissue are cultivation; (2) technologies for culti- loids as fat substitutes in hamburgers is sufficient for DNA extraction, vating microalgae and the products of anticipated to create a demand for these polymerase chain reaction (PCR) these algae; and (3) use of algal tech- substances. In the Philippines the eco- amplification, and analysis. nologies for solving ecological and nomic importance of sea weeds has

already surpassed that of coconut

Other reports on seaweeds cov- A number of reports on culture Cladophora and Enteromorpha are ered their lipids, heavy metal ion uptake, conditions that maximize the yield of among the recommended algae for the quality of the biocolloid of red and products such as carotenoid pigments evaluation of heavy metal contaminabrown algae, and a demonstration of or unsaturated fatty acids were tion of estuaries. antibiotics in sea weed extracts. presented.

The use of algae in oxidation ponds

A major problem applicable to to decompose organic pollution in TECHNOLOGIES FOR

unicellular algae and not to filamen- industrial, farm, and domestic waste CULTIVATING MICROALGAE tous forms such as Spirulina is the har- waters is an active area of research. AND THE PRODUCTS OF vesting of the crop from a dilute aqueous The treatment of effluents from palm THESE ALGAE

suspension. Flocculation, filtration, and oil mills and rubber treatment plants in

centrifugation are the common proce- Malaysia is being studied. In all these M.A. Borowitzka (Murdoch Uni- dures being studied.

studies a major goal is the recovery of versity, Australia) introduced the topic

purified water. A remaining problem is by reviewing the variety of products THE USE OF ALGAE FOR finding an economical method for already being derived from algal cul- SOLVING ECOLOGICAL harvesting the produced algal biomass; tures. Dunaliella is being cultured for AND ENVIRONMENTAL otherwise, the procedure just substiits beta carotene content and, along PROBLEMS

tutes an algal biomass for the previous with Spirulina, it is being produced on

organic waste materials. a commercial scale in Australia, Italy, The last topic was introduced by Another aspect of algal cultivation Israel, and the United States. B. Whitton (University of Durham, is encouraging the growth of nitrogenHaematococcus produces astaxanthin. United Kingdom). The ability of some fixing algae in farm fields. The producPorphyridium is grown for phycobilins algae to concentrate ions from the tivity of rice fields was shown to increase and for biocolloids. Other algae con- environment has led to their use as in the presence of such algae. The control tain hydrocarbons, fatty acids, and other pollution detectors, especiallyof heavy of noxious algae in drinking water bioactive substances.

metals. Both planktonic and benthic sources is another subject of interest to A major problem in the large scale algae from marine and freshwater environmental public health officials. farming of unicellular algae is the con- were shown to be able to accumulate trol of competing organisms. Dunaliella some metals. Research on the most SUMMARY has the unique advantage of the ability appropriate species for detecting specific to grow in high salinity media where elements is being conducted. In another Most of the reports dealt with subcompetitors are inhibited.

aspect based on these properties of the jects that are not new, but their appliA number of diatoms and dinoflagel- algae, the species composition of the cation to local problems was interestlates are being cultivated primarily to algae in a body of water functions as an ing. Commercial sea weed aquaculture serve as food in aquaculture hatch- indicator of the chemical composition in this region is less than 20 years old, eries. Some larvae of highly valued inver- of the water. The algal composition but it is fast growing and already signiftebrate animals require specific algae blooming in effluents from different icant to the economy of the Philippines. for their normal development. mines or from ore containing soil is Indonesia, Thailand, and Malaysia also

The recent interest in highly unsat- said to be unique for the specific metal are rapidly developing this resource. urated fatty acids for human nutrition ions that are present. Mass cultures of The availability ofsunshine, water, and has led to studies on cultivation of some such metal concentrating algae are being manpower makes the region suitable diatoms and other algae. Many of these considered for the detoxification of for cultivating algae. The interest and cultures are being done not in open industrial effluents.

enthusiasm among the young scientists ponds but in closed culture chambers. Whitton also indicated that micro- from Southeast Asia who attended this New designs of such “photo bioreactors” analysis of small samples of dried algae conference indicate that this is indeed were reported. Closed transparent indicated the presence of specific metals a growing enterprise. It reflects the tubular systems appear to be popular; in their environment. Dried and stored general spirit of this rapidly growing both horizontal and vertically held herbarium specimens can, therefore, region. With the development of new tubular systems were described. These serve as good records ofenvironmental markets for algal biocolloids, I foresee types of bioreactors are expensive and conditions at the time of their collec- rapid development of this area of marine are therefore suitable for the produc- tion and can be used for comparison to biotechnology in the near future. tion of very highly valued substances. the present state of the water.

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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