Search

堆積軟岩中に構築される地下空洞の挙動を予測するには，ひずみ軟化・硬化特性，ダイレイタンシーなど，軟岩特性や間隙水圧を考慮する必要がある．また，大断面空洞掘削問題では，空洞を分割して掘削するため，逐次掘削解放により空洞周辺岩盤の拘束圧，ひずみ速度が掘削過程で変化する．そこで，本研究においては，軟岩特性を再現できるひずみ軟化型弾粘塑性モデルに拘束圧依存性とひずみ速度依存性を考慮する関数を導入した．そして，これらの関数を導入したひずみ軟化型弾粘塑性水‐土連成有限要素解析を用いて堆積軟岩空洞の掘削問題に適用し，計測値と比較することで本解析手法が軟岩地下空洞の掘削時挙動予測に適用可能であることを明らかにした．

Acoustic emission (AE) and microseismic (MS) events are indicators of rock fracturing or damage as the rock is brought to failure at high stress. By capturing the AE/MS events, underground excavation induced rock mass degradation or damage can be located and evaluated. A better understanding of the extent and shape of the excavation damaged zone (EDZ) or yield zone around caverns helps to arrive at safe and economic design and construction of the caverns. For this purpose, one needs to understand the AE mechanism associated with the excavation process. In the present study, a coupled numerical method is used to study AE at the Kannagawa underground powerhouse cavern in Japan. Two codes, Fast Lagrangian Analysis of Continua (FLAC), a finite difference code and Particle Flow Code (PFC), a distinct element code, are coupled. The motive to apply the FLAC/PFC coupled approach is to take advantage of each modeling scheme while at the same time minimizing the requirement for computational resources. The coupling is realized through an exchange of displacements, velocities, and forces in each cycling step. The rock mass surrounding an AE sensor is modeled using PFC and the remaining rock mass is modeled with FLAC to consider the geological complexity and the excavation sequence. In this manner, the AE activities at AE sensor locations of the Kannagawa cavern were simulated and found to be in good agreement with field monitoring results. This approach takes account of stress redistribution and provides stress and displacement patterns in the rock mass that are consistent with AE observations for excavation design. The observed AE activities in the rock mass can thus be utilized to assess the effectiveness of the rock support system and the overall stability of the cavern.

Most back-analyses in geotechnical engineering are based on methods that utilize field displacement monitoring data. In the present study, a novel method is developed to back-calculate rock mass strength parameters from AE (acoustic emission) monitoring data in combination with FEM stress analysis. The method is based on the important concept of generalized AE initiation threshold of rock masses, established from comprehensive data analysis of laboratory test and underground monitoring programs using AE and microseismic (MS) techniques. An easy-to-use Wizard is developed in Microsoft Excel™ to assist site engineers to perform the back-analysis. The efficient solver in Excel is utilized to reach the optimization solution of an objective function with constraints. The Wizard allows the user to complete the analysis process in an interactive fashion. One example is given to demonstrate the back-analysis process using AE monitoring data recorded from a cavern site. The rock mass strength parameters identified from this approach compare well with field test data, suggesting that the tool can be used effectively to back-calculate rock mass strength parameters from AE monitoring data.

The Geological Strength Index (GSI) system, proposed in 1995, is now widely used for the estimation of the rock mass strength and the rock mass deformation parameters. The GSI system concentrates on the description of two factors, rock structure and block surface conditions. The guidelines given by the GSI system are for the estimation of the peak strength parameters of jointed rock masses. There are no guidelines given by the GSI, or by any other system, for the estimation of the rock mass’ residual strength that yield consistent results. In this paper, a method is proposed to extend the GSI system for the estimation of a rock mass's residual strength. It is proposed to adjust the peak GSI to the residual GSIr value based on the two major controlling factors in the GSI system—the residual block volume V b r and the residual joint condition factor J c r . Methods to estimate the residual block volume and joint condition factor are presented. The proposed method for the estimation of rock mass's residual strength is validated using in-situ block shear test data from three large-scale cavern construction sites and data from a back-analysis of rock slopes. The estimated residual strengths, calculated using the reduced residual GSIr value, are found to be in good agreement with field test or back-analyzed data.

大規模岩盤空洞掘削時の情報化設計施工では，事前設計段階における不確実性を補うため，掘削中の計測データに基づく逆解析により岩盤物性を再評価し，その後の岩盤挙動を精度良く予測することで支保設計の合理化が図られる．本論文では，原位置岩盤の破壊過程と対応した応力状態の変化を迅速かつ的確に把握する手段として有効性が確認されているAE(Acoustic Emission)計測に着目し，原位置岩盤の一軸圧縮強さσcmの関数で表わされるAE発生応力レベル式を設定し，原位置で計測されたAE挙動とFEMにより算定した岩盤内の応力状態とを組合せることにより原位置岩盤の強度定数を同定する新しい逆解析手法を提案した．そして，原位置空洞掘削時に取得したAE計測データを用いて，その手法の有効性を確認した．

Application of pervaporation membranes to practical separation and purification processes would be much more attractive if the separation performance (flux and selectivity) can be further improved. In addition to higher flux and selectivity, membrane stability at higher temperatures is quite important for efficient and economic separation in practical processes, considering that pervaporation at higher temperature preferably gives higher fluxes, resulting in smaller required membrane areas. In this respect, inorganic porous membranes could find a wider application in practical separation and purification processes. In this work, porous silica‐zirconia membranes of pore size less than 1 nm were fabricated by improved sol‐gel techniques to study the pervaporation characteristics of various aqueous organic solutions (isopropanol, 1‐propanol, acetone, tetrahydrofuran, and ethanol) at temperatures from 50°C to their normal boiling points. The water fluxes for these aqueous mixtures, with the exception...

The rock mass failure process is characterized by several distinct deformation stages which include crack initiation, crack propagation and coalescence. It is important to know the stress levels associated with these deformation stages for engineering design and practice. Extensive theoretical, experimental and numerical studies on the failure process of intact rocks exist. It is generally understood that crack initiation starts at 0.3 to 0.5 times the peak uniaxial compressive stress. In confined conditions, the constant-deviatoric stress criterion was found to describe the crack initiation stress level. Here, generalized crack initiation and crack damage thresholds of rock masses are proposed. The crack initiation threshold is defined by σ1−σ3=A σcm and the crack damage threshold is defined by σ1−σ3=B σcm for jointed rock masses, where A and B are material constants and σcm is the uniaxial compressive strength of the rock masses. For a massive rock mass without joints, σcm is equal to σcd, the long-term uniaxial strength of intact rock. After examining data from intact rocks and jointed rock masses, it was found that for massive to moderately jointed rock masses, the material constants A and B are in the range of 0.4 to 0.5, 0.8 to 0.9, respectively, and for moderately to highly jointed rock masses, A and B are in the range of 0.5 to 0.6, 0.9 to 1.0, respectively. The generalized crack initiation and crack damage thresholds, when combined with simple linear elastic stress analysis, assist in assessing the rock mass integrity in low confinement conditions, greatly reducing the effort needed to obtain the required material constants for engineering design of underground excavations.

Rock mass characterization is required for many applications in rock engineering practice including excavation design, support design, stope design, amongst others. For these purposes, it is necessary to obtain design input parameters such as deformation moduli and strength parameters for numerical modeling. Although such parameters can ultimately be determined from in situ tests, at the preliminary design stage, where access to underground is limited, the practical way to obtain these parameters is to apply a rock mass classification system to characterize the rock mass and estimate the rock mass properties. Over the years, many classification systems, such as RQD, Rock Mass Rating, Q and Geological Strength Index (GSI) systems, have been developed. Amongst them, the Q system is widely used for rock support system design and the GSI system is used for estimating design parameters. The GSI system is the only rock mass classification system that is directly linked to engineering parameters such as Mohr–Coulomb, Hoek–Brown strength parameters or rock mass modulus. However, the application of the existing GSI system is hindered by the facts that the use of the system is to some extent subjective and requires long-term experience. In the present study, a quantitative approach to assist in the use of the GSI system is presented. It employs the block volume and a joint condition factor as quantitative characterization factors. The approach is built on the linkage between descriptive geological terms and measurable field parameters such as joint spacing and joint roughness. The newly developed approach adds quantitative means to facilitate use of the system, especially by inexperienced engineers. The GSI system is applied to characterize the jointed rock masses at two underground powerhouse cavern sites in Japan. GSI values are obtained from block volume and joint condition factor, which in turn are determined from site construction documents and field mapping data. Based on GSI values and intact rock strength properties, equivalent Mohr–Coulomb strength parameters and elastic modulus of the jointed rock mass are calculated and compared to in situ test results. The point estimate method is implemented to approximate the mean and variance of the mechanical properties of the jointed rock masses. It is seen that both the means and variances of strength and deformation parameters predicted from the GSI system are in good agreement with field test data.

本論文は, 地下深部に建設された揚水発電所における地下空洞掘削時の各種計測挙動を分析し, まず, 空洞掘削に伴う周辺岩盤のゆるみ領域を塑性領域と非塑性領域に区分して定義した. そして, 各種岩盤挙動計測結果からゆるみ領域および塑性領域を評価する方法を提案し, 実際の大規模地下空洞掘削時の着目測線における各種岩盤挙動計測結果の分析により, 塑性領域の評価方法の妥当性について論じた. さらに, 空洞掘削時の周辺岩盤の実挙動および提案した評価手法によるゆるみ領域に基づき, 岩盤の材料特性を変化させた解析結果の比較検討により岩盤挙動を表現し得る岩盤の力学特性について論じた.

本研究では, 節理などの不連続面が多数介在する不連続性岩盤における大規模地下空洞掘削時の異方的な岩盤挙動を予測・評価するため, 任意の一方向に卓越する節理の破壊を考慮した等価連続体解析手法を提案した. 本手法は, 岩盤の強度・変形異方性に加え, ひずみ軟化挙動を考慮できることが特徴であり, これを幾つかの節理群が存在する堆積岩系および火成岩系の不連続性岩盤における空洞形状, 土被りが異なる既設地下発電所空洞の掘削解析に適用した. その結果, 本手法が不連続性岩盤における大規模地下空洞掘削時の異方的な岩盤および支保の挙動を概ね再現できることを確認した.

Carbon nanotubes have been attracting considerable attention because of their unique physical properties and their potential use in a variety of applications. Multi-walled carbon nanotubes (MWNTs) have properties which make them intrinsically suitable for acting as field emitters, such as sharp tips with an nm-scale radius of curvature, high mechanical stiffness, chemical inertness and electrical conductivity. We have studied the synthesis and purification of MWNTs. MWNTs were made by a d.c. arc method. We have developed a high-yield production method for MWNTs using a rotating cathode arc method. The advantages of this method are high stability and reliability of handling, and continuous mass production is possible with this method. The development of a purification method for carbon nanotubes is quite important for the utilization of carbon nanotubes. Two purification methods of MWNTs from cathode deposition by arc plasma were conducted by means of the different oxidation rates of various graphites. One is a chemical method and the other is a physical method. Both can purify MWNTs up to their optimum conditions. Using field-emission microscopy (FEM), emission patterns from MWNTs were observed. Conical beams from open-ended MWNTs were observed, and the emission was very stable. Further to the FEM study, cathode ray tube (CRT) lighting element equipped with MWNT field emitters was manufactured. Stable electron emission, adequate luminance and the long life such CRTs demonstrate that MWNTs are a very promising material for field electron emitters.

Preparation of monolithic TiO2-impregnated SiO2 aerogels (SiO2–TiO2 aerogels) with controlled microstructure was investigated. Tetraisopropylorthotitanate–acetylacetone mixture was impregnated to microstructure-designed silica alcogels and was decomposed during alcohol supercritical drying (SCD). The microstructure of these SiO2–TiO2 aerogels reflected that of the corresponding SiO2 aerogels. Anatase was detected by X-ray diffraction. Some of titanium elements were included in silica matrix, and the others existed as particles with 100–150 nm on the surface of the matrix. Titanium content was 25–34 at.% in SCD without zeolite, whereas SCD with zeolite increased it to over 40 at.% and decreased the amount of the particles on the surface. The SCD with zeolite was considered to prevent titanium components from being removed from the matrix with silica alcogel components.

Resistivity of sintered metal oxides is known to change as a result of irradiation of atomic hydrogen, deuterium, nitrogen, and oxygen, but not as a result of irradiation of symmetrical diatomic molecules of these atoms. Thin films of nickel oxide, cobalt oxide and manganese oxide were formed by pulsed-laser deposition so as to enhance the sensitivity to atomic beams. The 4th harmonic of the Nd:YAG laser (λ=266 nm 4.8 J cm −2 ) was focused on sintered pellets, and thin films were deposited on pyrex glass substrates. The partial pressure of the oxygen gas P o2 , and the substrate temperature, T g , are crucial parameters for the formation of transparent monoxide-like films. Optimum conditions were determined in the range of P o2 =1.3×10 −4 –1.3×10 Pa and T g =400–600°C. The films were characterized by X-ray photoelectron spectroscopy and X-ray diffraction. The monoxide-like films are found to be more sensitive to atomic beams than sintered oxides and even NiO single crystals.

Optical emission of the ablated particles in pulsed laser deposition of NiO films was measured dynamically. The emission spectra showed species of the ablated particles. There are three types of light emitting particles, that is, the laser induced plasma near the target, two groups of the depositing ionized particles or the neutrals. The streak photography displayed their kinetic motions. Velocities of the ionized particles were almost proportional to the square root of the incident laser fluence ranging from 5 to 150 J cm−2. It is possible to control the kinetic energy of particles incident onto a substrate by adjusting the laser fluence.

This paper mentions about the permanentmagnet synchronous motor (PMSM) propulsion system and its energy-saving performance confirmed through running tests on the Ginza Line of Tokyo Metro Co., Ltd. Comparing the conventional IM system installed Ginza Line with the PMSM system, the PMSM propulsion system has achieved 12.5% power consumption reduction in powering. In this paper, we describe the outline of the PMSM propulsion system and show results of the energy-saving performance evaluation tests carried out for more than 1.5 years.

Thin films of polyperinaphthalene (PPN) have been obtained by Nd:YAG pulsed laser deposition with a target of perylenetetracarboxylic dianhydride. Components of the films depend on the power and wavelength of the laser light, which is verified by absorption spectra, Raman scattering spectra, and in situ mass spectra. The optimum conditions for the PPN film formation is 10 mJ cm−2 at 266 nm.

The main action of SU in the treatment of diabetes mellitus is the stimulation of insulin secretion, and the extrapancreatic action including stimulation of insulin actions in glycogen synthesis and inhibition of glucose production in liver is also reported. The indication of SU in the treatment of diabetes mellitus is for NIDDM usually after diet therapy or suitable exercise therapy. In IDDM and several special cases including diabetic ketoacidosis, severe infection, pregnancy, poor-controlled NIDDM, gangrane, surgery operation, severe renal or hepatic failure et al. insulin therapy should be started. In mild NIDDM, gliclazide, tolbutamide or acetohexamide is used, and in more severe NIDDM glibenclamide is used. The action time of chlorpropamide is very long, usually from 20 to 60 hours, therefore special care should be taken for hypoglycemia. As the causes for secondary failure, transition from NIDDM to IDDM, failure of diet therapy, glucose toxity and others are considered.

The photosynthetic machinery of photosynthetic organisms is embedded in membrane composed from pigments, proteins and lipids. The unique lipid composition of thy -lakoid membrane can determine its functions. The alteration of the fatty-acid composition of glycerolipids in membranes can affect the physical characteristics of the membrane. Consequently it can affect the dependence of photosynthetic activities on the temperature of environment and the tolerance to temperature stresses.

We reviewed 546 operative cases in haemodialysis patients during the past 8 years between June 1990 and May 1998. The average age of the 257 male and the 289 female patients was 57.1 years. The average period of haemodialysis was 14 years and 4 months. We discussed the etiology, pathological focus, frequency, symptoms, problems and operative indications. Carpal tunnel syndrome occurred most frequently, occupying 289 cases. Short-term postoperative results were positive in the initial case within 6 months after the occurrence of the first symptoms. Because no effective method preventing recurrence existed, synovectomy was used as much as possible in the initial operation. Surgical treatment was used for amyloid arthropathy in 15 shoulders. It was effective in cases resistant to any conservative treatment. For the knee joint, the arthroscopic synovectomy was performed in 8 cases, and total knee replacement in 6 cases. The results of the total knee replacement cases were good. However, recurrences were observed in 40% of the synovectomy cases. In the hip joint, the curettage and bone grafting were performed in 7 hips of 6 patients. All bone grafts were consolidated and there was no case of postoperative pathological fracture. In some cases with destructive spondyloarthropathy, the vertebrae involved spontaneously fused without severe kyphotic deformity. A case with mild pain and without neurological deficit can be treated conservatively. A case with severe pain, instability, and myelopathy indicates operative measures must be taken. Attention must be paid for a possible collapse of the grafted bone after the cervical level two anterior fusion. Haemodialysis patients are vulnerable to infection. This diagnosis is difficult to distinguish due to the weakened state of the immune system. Rigorous attention is required to prevent and detect infection in cases using artificial joints or instrumentation. The treatment of bone and joint disturbances from dialysis-related amyloidosis has become surgical due to the advancement of dialysis control. However, it remains one of the more conservative treatments. Determining the cause and establishing a method of treatment are desired as early as possible.

The role of membrane lipid unsaturation in the restoration of photosystem II (PSII) function and in the synthesis of the D1 protein at different temperatures after photoinhibition was studied in wild-type cells and a mutant of Synechocystis sp. PCC 6803 with genetically inactivated desaturase genes. We show that posttranslational carboxyl-terminal processing of the precursor form of the D1 protein is an extremely sensitive reaction in the PSII repair cycle and is readily affected by low temperature. Furthermore, the threshold temperature at which perturbations in D1-protein processing start to emerge is specifically dependent on the extent of thylakoid membrane lipid unsaturation, as indicated by comparison of wild-type cells with the mutant defective in desaturation of 18:1 fatty acids of thylakoid membranes. When the temperature was decreased from 33[deg]C (growth temperature) to 18[deg]C, the inability of the fatty acid mutant to recover from photoinhibition was accompanied by a failure to process the newly synthesized D1 protein, which accumulated in considerable amounts as an unprocessed precursor D1 protein. Precursor D1 integrated into PSII monomer and dimer complexes even at low temperatures, but no activation of oxygen evolution occurred in these complexes in mutant cells defective in fatty acid unsaturation.

The concentration of brain catecholamines were measured and compared in the experimentally made hyperosmolar diabetic, diabetic and normal control rats in order to clarify the metabolic changes of the brain in these states. Diabetes was induced with streptozotocin and hyperosmolarity was achieved through deprivation of water for 50 hours prior to experimentation. Dopamine, norepinephrine and epinephrine concentrations were measured in the left cerebral cortex, hypothalamic-thalamic area, cerebellum and medulla oblongata. Dopamine and norepinephrine concentrations were significantly elevated in the cerebral cortex, hypothalamic-thalamic area and cerebellum of the dehydrated hyperosmolar-diabetic rats relative to those of normal controls (p0.01-0.05). In diabetes with high blood sugar level, the norepinephrine concentration was significantly elevated in the cerebral cortex, cerebellum and medulla oblongata, and these changes generally paralleled the increase in fasting blood glucose. It was concluded that hyperosmolarity due to dehydration contributed these changes. The findings of this study further suggest that changes in brain catecholamines may be involved in the nervous system disturbances that occur in the dehydrated hyperosmolar-diabetes and severe diabetes.

高地圧下における地下空洞掘削においては, 応力再配分の過程で周辺岩盤内に分布する既存の微小亀裂の開口・進展および新規亀裂の発生によりゆるみ領域が形成される. このゆるみ領域の評価は空洞の設計および計測管理上の重要な課題の一つであり, これらに基づく空洞の合理的な設計体系の構築が必要とされている. 本研究では, 岩盤内の応力変化に対する指標としてAE (Acoustic Emission) に着目し, 室内試験におけるAE挙動を, 粒状体による個別剛体要素法を用いて再現し, 応力状態の変化に伴うAE挙動の分析を行った. さらに, 空洞掘削時の応力履歴と原位置でのAE挙動を比較・分析することにより, AE計測による空洞周辺岩盤の応力状態の変化を定量的に評価する手法についての検討を行った.

A rare thyroid tumour is described. It started as a papillary cytoadenoma 20 years ago, followed by the appearance of a papillary adenocarcinoma 6 years later. At that time most of the tumour was excised, except for a small portion which had invaded the trachea. Post-operatively 6,000 rads of Co60 was given to the neck; the tumour remained quiescent for 18 years until two years ago, when a recurring fibrosarcoma appeared in her neck. It is suggested that this tumour was a radiation-induced sarcoma.

The ability of antibiotics to enter cells, especially phagocytic cells, may be an important factor affecting therapy for infections caused by organisms which survive and proliferate intracellularly. It is well known that macrolides and clindamycin have high intracellular penetration ability. We studied the uptake of rokitamycin (RKM), a new oral macrolide, using rabbit alveolar macrophages and 2 other macrolides for comparison. Intracellular concentrations of erythromycin and josamycin were, respectively, approximately 20 and 40 times higher than extracellular concentrations when they were incubated at an initial extracellular concentration of 5 micrograms/ml (I/E = 20.1 +/- 2.6, 40.8 +/- 7.4). In comparison to these 2 macrolides, the uptake of RKM was massive and very rapid. The cellular concentration of RKM was approximately 120 times higher than the extracellular concentration. Uptake of the 3 macrolides by rabbit alveolar macrophages at 4 degrees C was approximately 10% of that at 37 degrees C. This study demonstrated that RKM was rapidly and massively accumulated by alveolar macrophages, and that the drug accumulation depends on temperature. These observations suggest that RKM therapy may be very effective for the treatment of some infectious diseases.

Mental retardation, hypogonadism, obesity, and abnormal blood sugar regulation were common findings in two siblings. In addition, the 17-year-old female patient showed short stature, muscular hypotonia in infancy, and small hands with tapering fingers suggesting Prader-Willi syndrome, and the 12-year-old male patient showed retinitis pigmentosa, normal height, and normal muscular tonicity suggesting Laurence-Moon-Biedl syndrome, though polydactyly was absent. Possible consideration was discussed.

A case of multiple extracranial meningiomas, occurring in the orbita, both ethmoidal sinuses and the frontal sinus of a 60-year-old man, is reported. These meningiomas were histologically similar and diagnosed as transitional type benign meningioma. On whole body examinations including CT scans, we could not find any other primary foci. There fore, these meningiomas were thought to be a case of multiple extracranial meningiomas occurring at the same time. As for multiple extracranial meningiomas, this is the first case report in Japan. In general, extracranial meningiomas have been thought to be derived from ectopic arachnoid cell rests. Our case will be extremely important in the light of the histogenesis of extracranial meningiomas.

Benign pedunculated intraluminal tumor of the esophagus is extremely rare. Although the correct diagnosis of this tumor is difficult, it should be extirpated early because, if untreated, it may result in death of the patient by progressive emaciation, bleeding from erosions, or acute airway obstruction. We present a case rescued from suffocation caused by regurgitation of a giant esophageal tumor. In the discussion on the difficulty of diagnosis, the necessity of repeated examination is emphasized. The classification of benign esophageal tumors is also discussed.