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Article type: Cover
1982 Volume 66 Pages
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Published: February 25, 1982
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Article type: Cover
1982 Volume 66 Pages
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Keisuke TSUJI, Yasumi KOTOU, Kazumasa TANAKA
Article type: Article
1982 Volume 66 Pages
1-7
Published: February 25, 1982
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The present paper reported on the development of the prototype coastal navigation support system, using personal computer (TEAC, PS-80) which recently became popular. The system has been constructed for the purpose of load reduction in chart works (ship positioning), so navigator will be released from chart works to keep more careful look out for safe ship operations. The system has the following functions; (1) The system indicates target name, bearing and distance on the CRT display. (2) The informations of ship course and speed are given by gyrocompass and electromagnetic log through A/D converter or by keyboard. (3) The system calculates the ship position from more than two target bearings. (4) The system indicates observed position and dead reckoning position with time on the CRT display. (5) The system indicates name, bearing and distance of next course changing point on the CRT display. (6) Using X-Y ploter, the ship positions are drawn on chart.
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Kazutami SHOJI, Yukito IIJIMA, Hiroshi SUZUKI, Kiyotaka SAITO
Article type: Article
1982 Volume 66 Pages
9-15
Published: February 25, 1982
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IMCO's resolution showed that the distance of the magnetic compass from electrical or magnetic equipment should be at least equal to the safe distance specified for the equipment. This paper describes about measured east-west magnetic field intensity produced by each nautical instrument and its safe distance obtained by a magnetometer. Each instrument was measured on a non-magnetic turn-table which was turned though 360° in a uniform geo-magnetic field, and the safe distance was measured in a direction giving the most influence. The safe distance measured this time on a radar scanner was over 3m, a fish finder, loran, omega and facsimile being 1 to 2m, ADF, clear view screen, a rudder angle indicator, an engine tachometer and an engine telegraph being less than 1m. Influence of electric source on or off to the equipment was not obviously observed in 7 of 17 nautical instruments.
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Min QIU, Hayama IMAZU, Akio M. SUGISAKI
Article type: Article
1982 Volume 66 Pages
17-21
Published: February 25, 1982
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Although the radar display presents the successive of target echo, but the measurement point of the target echo is not the point of target's center, because the shape of target echo is changed by target's size, range and aspect. This paper described about theoretical errors of the measurement point by two measurement methods, the root mean square of bearing random error obtained by experiment, and the effect of theoretical errors and measurement errors on vector analysis. Then some useful results were obtained for measurement method of target echo and vector analysis.
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Hiroshi ISHIDA
Article type: Article
1982 Volume 66 Pages
23-30
Published: February 25, 1982
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Empirical Wave Heights formulae are tested based on the visual wave observation data at Ocean Station T (29°N, 135°E) and also reported are the characteristics of the visual wave observation in this paper. Difficulty of the visual swell observation is much higher than the wind wave one. It is increased in the higher wind condition more than 10m/s. Visual composite wave heights tend to be constant, about 1.2m, at low wind conditions and increase to the 1.6th power of the wind speed at higher wind conditions more than 10m/s. There is estimated 3-hour wind leading time lag between winds and waves' development and decay. The empirical wave heights formula, using the wind speed 3 hours before, has the best result to the visual observation data. Generally Composite wave heights have higher wave heights in comparison with Scott's and Pierson-Moskowitz's formulae in high wind conditions. From the analysis of the visual wave observation data, it is proposed that it be better to observe one wave height and one wave period rather than to do wind wave and swell separately in the high wind condition when it becomes difficult to distinguish them except in the low wind condition.
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Akio YASUDA, Yasubumi KANAI, Susumu KUWASHIMA
Article type: Article
1982 Volume 66 Pages
31-38
Published: February 25, 1982
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A simple wave height meter is proposed using a simple microwave radar which has two detectors separated λ_g/8 (λ_g; microwave wavelength in waveguide) from each other inside the same waveguide where a Gunn oscillator is placed. A field test is carried out at off-Tateyama by placing the doppler radar at the bow of the ship, 5 meters above the see level. The result agrees reasonably with that obtained simultaneously by the conventional ultra-sonic wave height meter at the same position. Since the doppler radar and the signal processing circuit are quite simple in construction and inexpensive, it is expected after some more field tests that the present wave height meter will be widely used on merchant ships. A simple circuit to indicate the significant wave height is also proposed.
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Takashi KURODA, Mitsuo YOSHIDA
Article type: Article
1982 Volume 66 Pages
39-46
Published: February 25, 1982
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The purpose of this paper is to measure the images of sea affairs-the sea, the ship and the seafarer, and to examine the above subject. As samples 1872 persons were selected out of inhabitants in the six areas of Hyogo Prefecture. Using principal component analysis we found three factors-factor of dynamics, affection and professional evaluation. The obtained factor score were examined the significance of difference between sex, age and geographical environment by generalized variance under three way layout. The results were as follows: (1) In the image of the sea, dynamic image of the aged and the inlands were higher than the youngs and the seasides. Affective image were opposite. (2) In the image of the ship, dynamic image of the male, the aged and the inlands were higher than the others. Affective image of the southparts were higher than the northparts. (3) In the image of the seafarer, professional evaluation of the female and the inlands were higher than the others.
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Tsukasa NAGAHATA
Article type: Article
1982 Volume 66 Pages
47-55
Published: February 25, 1982
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This paper presents two models for determining the probability of deciding relative distance measured with the eye and the approximation by power function. The decision-making on the sea takes place in an environment in which states of nature, psychology, physiology and available information are fuzzy. Therefore, the models are based on the application of the fuzzy sets theory, the statistical probability theory and the entropy theory. The calculation performed by using the results of questionnaire about the far and near sense against target ships. The calculation results agreed well with the experimental concerning the distance of vision at sea.
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Shuji NISHI
Article type: Article
1982 Volume 66 Pages
57-65
Published: February 25, 1982
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The usable time and the positioning accuracy of the Phase II Global Positioning System (GPS) are analysed here by emphasizing the positioning conditions in Japan. The main results give as follows. (1) In the case of 5 satellites (NAVSTAR No.3-7), the usable time in Tokyo is 1.9 hours for 3-dimensional positioning and 3.2 hours for 2-dimensional positioning. (2) The addition of NAVSTAR No.8 hardly improve the positioning conditions in Japan. (3) The usable time distribution maps in the world are made and the positioning conditions in Japan are compared with those in another countries.
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Michiko YAMASHITA, Kazuo TAGUCHI
Article type: Article
1982 Volume 66 Pages
67-72
Published: February 25, 1982
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Phase lags (mostly, one cycle) of OMEGA Hawaii signal (13.6kHz) are often seen a few hours before the sunrise at Kagoshima, and those results were statistically reported by Taguchi. In this paper, a numerical analysis for this phenomena is presensed. The east-west propagation below an anisotropic ionosphere with a transverse static field is applied. It results that if the ionospheric coefficient of the first order mode in the daytime is located in the fourth quadrant, the phenomena under consideration can be realized at Kagoshima before sunrise.
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Hideo YABUKI
Article type: Article
1982 Volume 66 Pages
73-81
Published: February 25, 1982
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It is important for users of the Omega navigation syetem to know the optimum LOPs and their accuracies beforehand. This study was carried out to evaluate the accuracies in the western North Pacific area and to propose the recommendable station pairs in these area. Accuracy was evaluated by comparing position fix by the Omega system with those by the cross bearing, radar and the astronomical observation. The recommendable station pairs were selected in considerations of LOP geometry, signal propagation prediction and the accuracy. The following results were obtained: 1. The r.m.s. relative error of the A-C, A-E, C-E combination was 2.0n.m.〜2.8n.m. 2. The r.m.s. relative error of the C-D, D-H, C-H combination was 1.5n.m.〜2.8n.m. 3. The relative accuracy of the automatic receiver using the Pierce skywave correction model was 2n.m.〜3n.m. (r.m.s.).
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Kunisaburo YONETA, Takashi HIRAIWA
Article type: Article
1982 Volume 66 Pages
83-88
Published: February 25, 1982
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In the former paper, we evaluated macroscopically the accuracies of positions determined by two or three Omega position lines based on the data of A-C, A-D, A-E, A-H, C-D, C-E, C-H, D-E, D-H and E-H pairs which were measured at a fixed point (41°48'. 4N, 140°43'. 3E) from January 1, 1977 until December 31, 1977. The accuracies of Omega position lines however, fluctuate depending on the season and hour. In this paper, we attempted to evaluate in detail laying stress on specific pairs. The combinations were A-C, A-H; A-H, C-H and A-C, D-H pairs which were evaluated highly in the former paper. 1) Accuracies of determined positions when propagation corrections are carried out by the use of PPC tables. The standard deviations around predicted values (obtained by correcting the values shown in the PPC tables to the phase differences between the observation point and the two stations) are shown monthly in Figs.1 and 2 assuming that the measured values have normal distributions around each predicted value. Based on the σ of each pair and the intersecting angles of two or three position lines the radii of 95 per cent probability circles were calculated and shown in Figs.3 and 4. 2) Accuracies of determined positions when propagation corrections are carried out by the use of measured ones. Each day was divided into twenty-four hours and each month into two parts, thus a year was divided into 576 parts, and each condition was considered to be the same respectively. The differences between the mean values and the measured values for each part presented observation errors. Figs.5 and 6 show the standard deviations of each pair corresponding to each season and time. Based upon those data and the angles cut in two or three position lines the radii of 95 per cent probability circles were calculated and are shown in Figs.7 and 8.
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Qing Lian GAO, Yoshio MIYAZAKI
Article type: Article
1982 Volume 66 Pages
89-97
Published: February 25, 1982
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The leading aim of this paper is to explain with plain equations the relationships among the various particulars of Japanese fishing boats and then using these equations, determine a method for calculating the various particulars necessary in the basic design stage. Almost all the equations shown in tables 3 and 4 take tha form (1) Y=a+bX. In special cases, however, forms (2) Y=a+blnX and (3) Y=ae^<bX> are also assumed. Regression coefficients a and b are obtained by regression analysis and r^2_<xy> for all the equations are larger than 0.9. The procedure for calculating the various particulars of fishing boats is shown by the arrow diagram in Fig.1. First of all, calculate the full load displacement △_f and fish hold capacity FH from gross tonnage, then using △_f and FH as initial conditions, determine two sets of various particulars. The average values got from the two sets of data are the various particulars of fishing boat. The comparison between the average calculated value and that which is currently used for designing a Japanese fishing boat is shown in Fig.4. Eighty percent of the data is within a five percent range.
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Rihei KAWASHIMA, Shunji JANUMA, Kiyoshi AMAGAI
Article type: Article
1982 Volume 66 Pages
99-107
Published: February 25, 1982
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In the experiments using the self-proppelled model ship, capsizing phenomena were observed after the lurching motion thought to be the low cycle resonance. Concerning these phenomena, the non-linear Mathieu's function was used for describing the rolling motions. The authors solved these equations numerically by means of Runge-Kutta-Gill method and tried to show the agreement of experiments and theory, comparing between the calculated and the measured rolling motions in the experiment. Further, the simulations for the rolling motion of fishing boats due to waves were performed numerically and discussed.
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Tatsuro MATSUOKA, Rihei KAWASHIMA
Article type: Article
1982 Volume 66 Pages
109-116
Published: February 25, 1982
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The authors have carried out experiments concerning the sea keeping quality of fishing boats in wind waves. An experiment with a model of the 124GT trawler provided the authors with the records of pitching of 46 runnings, and spectral analysis was carried out. On the other hand, motion spectra were computed on the basis of linerized theory from observed wave spectra and the frequency response functions calculated with OSM according to two hypotheses of long-crested and short-crested waves. In addition to spectra, n-th moments and ε, 1/n mean values of maxima computed by the probability density function of m_0 and ε obtained from calculated spectra were compared with observed values. The conclusions were obtained from a comparison of observed and computed results as follows. The spectrum, n-th moments, band-width parameter and 1/n mean values of the pitching motion of the fishing boat can be predicted with good accuracy by the procedures with wave spectra and frequency response functions mentioned above according to the hypothesis of short-crested waves, except in the cases of running in following or quartering seas and Fn. of under 0.3.
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Hiroaki KOBAYASHI, Masahiko NAKATANI
Article type: Article
1982 Volume 66 Pages
117-125
Published: February 25, 1982
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It is well known that rudder effect can be inproved by increasing propeller revolution. Under uniform wind disturbance, increasing propeller revolution momentaly, ship's velocity can be more slowly to keep her course. (abbreviated Boosting maneuver). In this paper, boosting maneuver is proved to be very useful and the method is shown which presume the least possible velocity for course keeping by using boosting maneuver on phase portraits. Moreover, the varidity of this analysis is varified by some trials on the ship maneuvering simulator. Comparing these results with those of the simulator's experiments, they are in good coincidence.
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Toru SAWARAGI, Masayoshi KUBO, Shinichi AOKI
Article type: Article
1982 Volume 66 Pages
127-135
Published: February 25, 1982
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In harbors attacked by swells, cargo handlings are often interrupted by severe ship motions in waves. Furthermore, mooring lines of ships are sometimes broken due to ship motions. Authors develop a new mooring system containing dash-pots in order to reduce the moored ship motions. The system is investigated experimentally and analytically. The results obtained from this analytical model indicate a good agreement with the experimental ones. So the moored ship motions with various kind of dash pots are calculated by this analytical model. As the results, it is clarified that the mooring system with dash pots is very useful for the ship to reduce the moored ship motions. Further the design of optimum dash pot is proposed.
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Kazumasa TANAKA
Article type: Article
1982 Volume 66 Pages
137-143
Published: February 25, 1982
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The theoretical study on the critical navigation of a ore carrier (L_<pp>=247m, C_b=0.824) has been carried out from the viewpoint of structural seaworthiness in longitudinal strength. The navigable wave conditions were obtained by the same procedure for the single screw container ship, previously reported. From the results, it is shown that whipping of full ship due to slamming grows rapidly at lower ship speed in head sea condition because of large impact pressure coefficient and flat fore bottom. And, wave bending moment in following sea condition is larger than in head sea condition, so that the operations of full ship in heavy seaways should be dicided with attentions not only to slamming but also to wave bending moment. From the comparison of navigable wave condition between the present ore carrier and the previous container ship, it is found that the difference of structural seaworthiness in longitudinal strength between them is not significant in seaway of longer average wave period.
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Keinosuke HONDA, Satoshi KOSUDA
Article type: Article
1982 Volume 66 Pages
145-152
Published: February 25, 1982
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In order to find a weak point for mooring, authors carried out the model experiments on the above title problem by using of 1/50 scale model of GT 5,000 ton cargo ship. The external force acting on the model ship in a water tank with generator is wind force, no wave. The wind-direction were changed at every 15 degrees from the line drawed vertically to a line between both anchors. Main experimental results are as follows; (1) A Open-moor of which the leg angle between both chain cables is about 60° is more safety because of smaller yawing motion, as that being obtained by YONEDA. However, it should be taken notice that the shock load acting on the riding cable is greater than that at a single anchor, if the wind-direction is agreed with each cable line, and also that the most possibly raises a dragging anchor in such case. (2) Using Engine-astern in order to control the yawing motion at anchor has the effect of checking gently and smaller, as that being obtained by T.S.HOKUTO-Maru. However, such engine motion at anchor under heavy weather will be brought on the dragging anchor owing to the shortage of an anchor-holding power.
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Kinzo INOUE
Article type: Article
1982 Volume 66 Pages
153-161
Published: February 25, 1982
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The author tried to evaluate by means of simulation that to what degree cable tension can reduce through the effect of bow thruster which was operated so as to lessen the difference of the angle between the direction of the wind and the ship's head. The results of the simulation showed that not only cable tension but also the extent of swing motion reduced significantly by application of bow thruster, and gave us some instructions regarding the operation of bow thruster as follows; (1) The degree of the effect is not concerned in the starting point of operation of bow thruster. (2) It is not desirable to do so sensitive control for the small difference of the angle between the direction of the wind and the ship's head. (3) In the present condition, it is suitable to permit the steady swing motion to some extent, in this sense, the adequate magnitude of the thrust of bow thruster seems to be 60〜80% of the frontal wind pressure of the ship. (4) Then, it is expected that the magnitude of cable tension decreases by about 40%, and the extent of swing motion decreases by 35% at least.
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Hiroshi KANDA, Yoshio MURAYAMA, Masato TANAKA, Kiyoshi SUZUKI
Article type: Article
1982 Volume 66 Pages
163-171
Published: February 25, 1982
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This paper provides and discusses the results of three type test ships, obtained in accordance with the evaluation method proposed in the first report. The evaluation was made by the vibration ride quality index, vibration sensibility magnitude and dynamic response index (DRI) related to spinal injury. These methods permit the precise evaluation of the vibration effect from the standpoint of human tolerance according to the particulars of the high speed ships and on such measuring conditions as the wave height, the wave directions relative to the ship and the ship speed. A phenomenon worthy of attention is that the evaluation value on the vibration-isolating seat for the helmsman was remarkably large compared with those on floor under the helmsman's seat. From the above, the effect of the vibrationisolating seat should be re-examined. And the value of DRI tends to become so large as to cause the deformation of vertebral bones when the crest factor is larger than 5 and 6, and consequently, new proposal would be necessary to settle the evaluation criterion for the repeated shocks and vibrations by means of DRI.
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Saburo SUZUKI
Article type: Article
1982 Volume 66 Pages
173-180
Published: February 25, 1982
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It had been discussed many times that which rules of nautical road apply between a power-driven vessel which is under way but stopped and a power-driven vessel which is proceeding, so it seemed that it should apply "Good Seamanship Rules". Nevertheless the discussion has been come about recently that the relation on relative meeting shall apply between them, example "The Devotion II" and "The Tozai Maru". I achieved the conclusion with the following reasons that they shall apply the relation on relative meeting by logical interpretations, irrespective of grammatical interpretations. 1. Treating a power-driven vessel which is under way but stopped like a power-driven vessel which is proceeding in point of "Lights and Shapes" 2. Can't distinguish a power-driven vessel which is proceeding very very slowly into a power-driven vessel which is under way but stopped. 3. Don't exist the social reasonable facts which shall lighten any obligations. 4. A power-driven vessel which is under way but stopped shall observe "The Sailing Rules".
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Yoshifumi WADA
Article type: Article
1982 Volume 66 Pages
181-190
Published: February 25, 1982
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Where one ship is crossing the channel from one side of it to the other, and another ship is proceeding along the same channel, the crossing rule governs the case. According to Rule 9 (d) of the 1972 Regulation, vessels must not cross a narrow channel if by doing so they impede the passage of any other vessel which can safely navigate only within the channel. Which rule governs the situation when a vessel crosses a narrow channel disregarding Rule 9 (d)? IMCO provided that the relevant Steering and Sailing Rules shall be complied with. I, however, conclude that the rules of good seamanship governs the above case.
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Kiyoshi OIKAWA, Masahiko IBARADA
Article type: Article
1982 Volume 66 Pages
191-199
Published: February 25, 1982
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To increase the safety of life at sea is to decrease the risk of the losses of the vessel and the life and the effectiveness of lifesaving systems will be affected from time factor of the survival operation. The main purpose of this paper is to develop the relation between the use of lifesaving appliances and vessel's casualties. The study and the investigation are given in this paper as follows; 1) Suitable lifesaving systems for survival operation are varied by the kind of the sea casualty, size and kind of the vessel, ability of the survivor, the circumstance and the envilonment of the vessel faced with. 2) The time of evacuation and retrieval is varied by the kind of the sea casualty and the lifesaving operation. 3) To succeed the survival operation, lifesaving appliances must be considered from the view point of each stage of the survival operation and the technical level of the seafarer. 4) The effectiveness of lifesaving systems must be considered by the use of lifesaving appliances and the time of evacuation and retrieval. The use of the inflatable liferaft is much effective than the lifeboat.
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Article type: Appendix
1982 Volume 66 Pages
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Article type: Appendix
1982 Volume 66 Pages
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Article type: Appendix
1982 Volume 66 Pages
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Article type: Appendix
1982 Volume 66 Pages
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Article type: Appendix
1982 Volume 66 Pages
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Article type: Cover
1982 Volume 66 Pages
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Article type: Cover
1982 Volume 66 Pages
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