JaLCDOI 10.18926/fest/11543
Title Alternative Fertilizer Microencapsulated with Biodegradable Polymer
FullText URL 007_127_131.pdf
Author Futaki, Sakae| Yoshizawa, Hidekazu| Matsuo, Mitsunori| Kusumoto, Masahiko| Kitamura, Yoshiro|
Abstract Many fertilizers are soluble in water, therefore their effect does not last for long time after fertilizing in soils. The nitrogenous fertilizers such as urea transported to groundwater cause serious agricultural contamination and health problems. To solve these problems, sustained release of fertilizer has attracted much attention. In this study, we attempted to prepare polylactide microcapsules with fertilizer by phase separation technique, which was a method of microencapsulation. Polylactide (PLA) was used as a biodegradable polymer bacause the biodegradable polymer has no influence on the soil and the ecosystem. The effect of preparation conditions such as stirring time and fertilizer concentration on morphology of microcapsule and on cumulative percentage released of enclosed urea was also investigated.
Keywords fertilizer polylactide microcapsule controlled release phase separation
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 127
End Page 131
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313894
JaLCDOI 10.18926/fest/11541
Title Alternative Upconversion property and light scattering in Tm(3+)-doped glass-ceramics
FullText URL 007_119_125.pdf
Author Miura, Yoshinari| Ding, Yong| Murata, Takashi| Himei, Yusuke| Nanba, Tokuro|
Abstract Glass-ceramics containing Pb(x)Cd(1-x)F(2) microcrystallites were prepared through heat treatment of Tm(3+)/Yb(3+)doped SiO(2)-Al(2)O(3)-PbF(2) glasses. The crystallite size was controlled by varying the heat-treatment time. By changing glass composition, two types of strong optical scattering, Rayleigh and Mie scattering modes were observed for the glass ceramics. In the case of Rayleigh scattering, the scattering region expanded to the long-wavelength side with increasing the heat-treatment time. On the other hand, in the case of Mie scattering, the region were hardly dependent on wavelength, and visible light was widely scattered. It was argued that the different scattering phenomena were caused by the different size of the crystallites or their morphogical texture. Furthermore, the glass-ceramics with strong optical scattering showed higher upconversion fluorescence intensity than the matrix glass. The mechanisms for the enhanced upconversion due to the scattering were discussed.
Keywords Optical scattering Glass-ceramics Oxyfluoride glass Microcrystallite Upconversion fluorescence
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 119
End Page 125
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313480
JaLCDOI 10.18926/fest/11538
Title Alternative Effects of ultrasonic treatment on the preparation of transparent glass-ceramic phosphor
FullText URL 007_113_118.pdf
Author Inoue, Teruhide| Nakashima, Mizuho| Nanba, Tokuro| Miura, Yoshinari|
Abstract The effects of ultrasonic surface treatment (UST) on the crystallization behavior and optical emission properties were investigated for the transparent glass-ceramics prepared from calcium aluminosilicate glasses co-doped with Eu(2+), Nd(3+). The glass-ceramics A were prepared by sintering a glass 45CaO・45Al(2)O(3)・10SiO(2) (mol%) containing 0.5Eu(2)O(3)+1Nd(2)O(3) under a 2% H(2)+98% Ar reducing atmosphere. In the glass-ceramics A, three crystalline phases, CaAl(2)O(4) (CA), CaAl(4)O(7) (CA2) and Ca(2)Al(2)SiO(7) (CAS) were commonly confirmed by X-ray diffraction. No drastic change in the amount of the precipitated crystalline phases was observed even in the case using UST of CA powders. It was suggested that the optical emission properties of the glass-ceramics A was responsible for the CA2 crystals. The glass-ceramics B were also prepared from a 51CaO・42Al(2)O(3)・7SiO(2) glass. The CA crystals were separately precipitated in the glass-ceramics B. In particular, a large amount of CA was successfully produced by stirring the UST suspension to prevent the sedimentation of the UST particles. The glass-ceramic B so-prepared showed strong photoluminescence but weak phosphorescence compared with other glass-ceramics B, indicating that the photoluminescence and phosphorescence were originated in different electron-trapping levels. The amount of the trap levels associated with the long lasting phosphorescence, such as oxygen vacancies, was probably small in the glass-ceramic B prepared with the stirring UST.
Keywords ultrasonic surface treatment (UST) surface crystallization glass-ceramics long lasting phosphorescence calcium aluminosilicate glass
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 113
End Page 118
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313433
JaLCDOI 10.18926/fest/11536
Title Alternative Long-term Trend of Rainfall at Tsudaka Farm of Okayama University
FullText URL 007_107_111.pdf
Author Moroizumi, Toshitsugu| Yomota, Atsushi| Miura, Takeshi|
Abstract Characteristics of long-term change in rainfall at Tsudaka Farm of Okayama University were analyzed with data during the 20 years, from 1979 to 1998. The typical results were as follows: (1) The average of annual rainfall was 1203 mm at average, 1726 mm at maximum, and 666 mm at minimum. (2) The decreasing rate of the annual rainfall was 5.37 mm/year. (3) Trend of rainfall intensity in each rainfall duration showed an increase of which rate were 0.005~0.256 mm/h/year, contrary to the annual trend. (4) Rainfall intensities in n-years probability were estimated using the maximum rainfall intensity for each rainfall duration.
Keywords Rainfall Rainfall intensity Rainfall duration Talbot formula Long-term trend Tsudaka Farm of Okayama University
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 107
End Page 111
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313813
JaLCDOI 10.18926/fest/11534
FullText URL 007_099_106.pdf
Author Kamboh Maqsood Ahmed| Oki, Yoko| Adachi, Tadashi|
Abstract A few wheat varieties including two Japanese wheat varieties were evaluated for their salt tolerance at seeding stage, their behavior to increasing salinity levels and role of Na exclusion capacity in salt tolerance mechanisms. The wheat varieties were grown in nutrient solution and subjected to 0 (control), 25,75 and 125 mM NaCl salinity levels for 7 days. Although the shoot growth was reduced while Na contents were increased progressively with increasing salinity in all varieties, the varieties were quite different in their response. Salt tolerant va rieties maintained less reduction in their root and shoot growth and better water relations in their shoots than salt sensitive varieties under saline conditions. The wheat varieties were quite different in their Na exclusion capacity. Poor growth in salt sensitive varieties might be due to higher accumulation of Na in their shoots resulting from low Na exclusion capacity of roots, higher Na transport to shoot and/or inferior compartmentation capability.
Keywords growth and mineral composition increasing salinity Na exclusion capacity salt tolerance wheat varieties
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 99
End Page 106
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313704
JaLCDOI 10.18926/fest/11532
FullText URL 007_091_098.pdf
Author Kamboh Maqsood Ahmed| Oki, Yoko| Adachi, Tadashi|
Abstract To evaluate hypoxic-salinity tolerance in wheat varieties, three Japanese varieties (Nourin-61, Chikugo Izumi and Shirasagi Komugi, relatively salt tolerant) and one Pakistani variety (Blue Silver, relatively salt sensitive) were grown under control, hypoxia, saline and hypoxic-saline conditions. The results suggested that relatively hypoxia and salt tolerant variety Nourin-61 was capable of producing the highest relative shoot yield under combined stress conditions. On the other hand, relatively sensitive variety to both hypoxia and salinity conditions, could not withstand harmful effects of combined stress. A more close correlation of plant growth characters between salinity and hypoxic-salinity than hypoxia and hypoxic-salinity indicated that varieties with higher salt tolerance would suffer less than varieties with higher hypoxia tolerance under combined stress conditions. And the balance of Na/K ratio in shoot tissues seems to be the major evaluation factor as the tolerant variety when salinity and hypoxia stress occur together.
Keywords hypoxia growth and ionic composition salinity salt tolerance wheat varieties
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 91
End Page 98
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313980
JaLCDOI 10.18926/fest/11530
Title Alternative Tendency of Main Sightseeing-areas based on the Number of Tourists for Some 30 Years in Okayama Prefecture
FullText URL 007_075_089.pdf
Author Ichiminami, Fumikazu|
Abstract In this paper, the tendency of the number of tourists was examined for some 30 years at several sightseeing-areas in Okayama prefecture. Recently, large-scale parks on well-known theme have been built in Japan, the management strategy of sightseeing-spots is becoming harder. However, it is important for us to understand the peculiarity of local sightseeing-areas and advertise the information on unsophisticated nature and culture linked with surrounding ecological system consistently. Sustainable management of sightseeing-areas is affected and sustained by the thought and life-style of peoples living in the adjacent areas.
Keywords Tourists Sightseeing-areas Sustainable Management Okayama Prefecture
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 75
End Page 89
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313698
JaLCDOI 10.18926/fest/11528
Title Alternative Damage factors analysis for small embankment dams due to the Hyogoken-Nambu earthquake special to Hokudan Town
FullText URL 007_055_074.pdf
Author Fujii, Hiroaki| Kunimasa, Kana| Nanba, Akiyo| Yokomizo, Takayuki| Nishimura, Shin-ichi| Shimada, Kiyoshi| Hori, Toshio| Nishiyama, Tatsuro| Wakitani, Yoshiaki|
Abstract This study was performed to clarify which factors affected damage to take-ike (small embankment dams for irrigation in Japanese) of Hokudan Town on Awaji Island in western Japan due to Hyogoken-Nambu earthquake. Multivariate and ordinary statistical analysis were carried out using documentary data (181 damaged and 328 undamaged dams), and ordinary one was done for the results investigated in situ. The model for the multivariate analysis was created with 13 items and 94 categories for 4 groups (Location, Geology Structure, and History of Dam). As a result, the factors causing to damage for dam are (1) the nearest fault (Nojima, Mizukoshi and D2), (2) embankment volume (the larger the more), (3) angle of crest axis to epicenter (diagonal and normal), (4) distance to the nearest fault (less than 500 m), (5) distance to the epicenter (8 to 14 km which almost agree to the location of seismic intensity 7 JMA), (6) play view of dam axis (3 or 4 axes), (7) angle of crest axis to nearest fault (diagonal and normal), (8) elevation of dam site (over 100 m), (9) surface geology of dam site (non-cohesive soil), (10) era of construction (prior to 1891), and (11) soil properties of embankment (constructed of sand, smaller penetration resistance).
Keywords Earth dam earthquake damage site investigation statistical analysis case study
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 55
End Page 74
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002314039
JaLCDOI 10.18926/fest/11525
Title Alternative A Study on Influence of Current Velocity on Phytoplankton
FullText URL 007_045_053.pdf
Author Li, Jinsong| Kawara, Osami| Ono, Yosiro|
Abstract The main problems caused by eutrophication result from the increase of phytoplankton. Therefore, controlling the increase of phytoplankton is the most important. In this study, we discuss the influence of current velocity on the growth of phytoplankton based on the field experiments and laboratory experiments. The laboratory experiments for the influence of current velocity on the growth have been conducted using circular channels, and the field experiments were conducted using a shallow pond. The results of the experiments show current velocity inhibits the growth of phytoplankton.
Keywords Eutrophication growth of phytoplankton influence of current velocity experiment
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 45
End Page 53
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313529
JaLCDOI 10.18926/fest/11523
FullText URL 007_039_044.pdf
Author Watanabe, Masaji|
Abstract We present some results of a finite element analysis for an unsteady flow in Kojima Lake. We also present an experimental result. The global positioning system was utilized in the experiment in order to record the temporal and the spatial data of a float traveling with the driving force of the fluid resistance. The spatial and temporal data were recorded to examine their correspondence with analytical results.
Keywords lake flow numerical simulation finite element method global positioning system
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 39
End Page 44
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313386
JaLCDOI 10.18926/fest/11521
FullText URL 007_031_038.pdf
Author Zhang, Fanghong| Tanaka, Yutaka|
Abstract Relationship has been discussed by Tanaka and Zhang(1999) between the sensitivity analyses based on influence functions and on Cook's local influence, and it has been shown that equivalent results are obtained under general conditions by these analyses in statistical modeling without/with equality constraints. However, a condition implicitly assumed in the proof in Tanaka and Zhang(1999) in the case with equality constraints does not necessarily hold. The present paper gives a complete proof without assuming the condition. Also a formula for the normal curvature is derived for the convenience of practical computation.
Keywords Local influence influence function equality constraints
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 31
End Page 38
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313336
JaLCDOI 10.18926/fest/11519
FullText URL 007_023_029.pdf
Author Sung, JiMin| Yang, WooSung| Tanaka, Yutaka|
Abstract Analysis of covariance selection models is a useful multivariate method to analyze the covariance structure of a multivariate normal distribution. It is used to reveal cause-and-effect relationships. In the present paper we review the theory and study numerically how the stepwise procedure of covariance selection works in actual data analysis. Then we try to develop a method of influence analysis in covariance selection, and show a numerical example to illustrate the usefulness of the method of influence analysis.
Keywords Covariance Selection Local Influence Influence Function Stepwise Procedure
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 23
End Page 29
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002314018
JaLCDOI 10.18926/fest/11515
Title Alternative Stability analysis of mathematical models of infectious disease
FullText URL 007_017_021.pdf
Author Murase, Akiko| Sasaki, Toru| Kajiwara, Tsuyoshi|
Abstract Dynamics of infectious disease in vivo is described by coupled differential equations. Stability analysis of the complicated systems is difficult without computer calculation, while stability analysis is, in general, important to investigate qualitative behaviour of models. Liu analyzes stability of systems describing HIV dynamics in vivo with a symbolic calculation software. The same method is used for stability analysis of a mathematical model of malaria.
Keywords mathematical model infectious disease dynamics in vivo stability analysis symbolic calculation
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 17
End Page 21
ISSN 1341-9099
language 日本語
File Version publisher
NAID 120002313783
JaLCDOI 10.18926/fest/11512
FullText URL 007_007_016.pdf
Author Ishii, Hiroyuki| Ishikawa, Hirofumi| Ohga, Yukio|
Abstract We have constructed a stochastic transmission model for lymphatic filariasis caused by Wuchereria bancrofti, and have analyzed its prevalence using computer simulations. In Pondicherry, India, where Wuchereria bancrofti has been spreading, the Vector Control Research Centre has carried out an integrated vector control strategy against malaria and filariasis for five years (1981~1985) with good results reported. Our study was aimed at evaluating the effect of vector control in the context of Pondicherry, and in particular the continuous effect for the post-control period. In this paper, we have used the LYMFASIM model proposed by Plaisier et al., the carrying capacity model by Rochet and the population dynamics model by us. In the LYMFASIM model and the carrying capacity model, we have modified the quantities of parameters in order to fit the models to the parasitological, entomological and epidemiological data in Pondicherry. We have combined the improved LYMFASIM model with the other models. Through simulations of our combinated model, we have compared the prevalence rate in the human population as well as the mean number of L3-larvae in the mosquito population, with and without vector control. As a result, the simulations show that the prevalence rate would be restrained for a long time even if only a small continuous effect of the vector control remains in the post-control period. However, the mean number of L3-larvae would recovered within a short time comparatively. This is because of the differences in life spans between human and mosquito as well as the incubation periods between the adult worm in the human host and L3-larvae in the mosquito vector.
Keywords Lymphatic filariasis mathematical model Pondicherry vector control Wuchereria bancrofti
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 7
End Page 16
ISSN 1341-9099
language 英語
File Version publisher
NAID 120002313471
JaLCDOI 10.18926/fest/11510
FullText URL 007_001_005.pdf
Author Ohga, Yukio| Ishikawa, Hirofumi| Doi, Rikuo| Ishii, Hiroyuki|
Abstract In our study, we have investigated the influence of the intermediate host population density on the prevalence of Echinococcus multilocularis in the definitive host using a mathematical model of transmission. For the vole population (intermediate host) in Hokkaido, a model of population dynamics has been constructed in this paper which follows the seasonal and annual fluctuations. In the northeastern area, the vole density appears to fluctuate periodically with a 4 year cycle. The prevalence of Echinococcus multilocularis in the fox population (definitive host) can be affected by the density of vole through the fox ingesting infectious voles. Therefore we have prepared a food habit function of foxes and the logistic distribution has been proposed. The simulations which have been carried out using the mathematical model for transmission of Echinococcus multilocularis together with the vole dynamics have indicated that the prevalence in foxes is correlated and synchronized with the population dynamics of vole. In addition they have also made us recognize that it is necessary to introduce a suitable food habit function into the transmission model.
Keywords Echinococcus multilocularis food habit of foxes Hokkaido population dynamics vole
Publication Title 岡山大学環境理工学部研究報告
Published Date 2002-03-22
Volume volume7
Issue issue1
Start Page 1
End Page 5
ISSN 1341-9099
language 英語
File Version publisher