In-situ Washing by Sedimentation Method for Contaminated Sandy Soil

We propose a new method of in situ soil remediation called in situ washing by sedimentation (IWS), accomplished by injecting a high air-pressure into a mixture of saturated water-sandy soil at a certain depth (D) and hydraulically separating the soil particles based on their particle size and density. This physical segregation exploits the distribution of contaminant in the soil by physically separating a selected contaminant-rich fraction. For the in situ application, the physical segregation by sedimentation and on-site water wash treatment happen as an integrated process. The advantage of IWS that the washing and segregation processes take place simultaneously during the remediation process, quick, effective and cheap since there are no costs for excavation of contaminated soil from the site. The effect of soil-water ratio and diameter geometry of the column on the effectiveness of segregation by IWS was investigated. A series of laboratory test were conducted to optimize the soil water ratio for the best segregation process. Soil-water ratio 1:2 (v/v) was found to be optimum for particle segregation produced by IWS . The suitability of IWS for Polycyclic Aromatic Hydrocarbon (PAH) remediation, such as Napthalene, Phenantrene and Pyrene, were examined by batch sedimentation column experiment. The laboratory experiment was effective to produce a distinct size segregation of the contaminated soil into the coarse and fine fractions, as well as the wash water, indicating that a significant reduction in Napthalene, Phenantrene and Pyrene level (90%) may be achieved. The experimental results show that the removal efficiencies depend on the initial concentration of PAH in the soil sample, the duration of washing and the addition of biosurfactant in the washing solution

Superlattice formation lifting degeneracy protected by non-symmorphic symmetry through a metal-insulator transition in RuAs

The single crystal of RuAs obtained by Bi-flux method shows obvious successive metal-insulator transitions at T_MI1~255 K and T_MI2~195$ K. The X-ray diffraction measurement reveals a formation of superlattice of 3x3x3 of the original unit cell below T_MI2, accompanied by a change of the crystal system from the orthorhombic structure to the monoclinic one. Simple dimerization of the Ru ions is nor seen in the ground state. The multiple As sites observed in nuclear quadrupole resonance (NQR) spectrum also demonstrate the formation of the superlattice in the ground state, which is clarified to be nonmagnetic. The divergence in 1/T_1 at T_MI1 shows that a symmetry lowering by the metal-insulator transition is accompanied by strong critical fluctuations of some degrees of freedom. Using the structural parameters in the insulating state, the first principle calculation reproduces successfully the reasonable size of nuclear quadrupole frequencies for the multiple As sites, ensuring the high validity of the structural parameters. The calculation also gives a remarkable suppression in the density of states (DOS) near the Fermi level, although the gap opening is insufficient. A coupled modulation of the calculated Ru d electron numbers and the crystal structure proposes a formation of charge density wave (CDW) in RuAs. Some lacking factors remain, but it shows that a lifting of degeneracy protected by the non-symmorphic symmetry through the superlattice formation is a key ingredient for the metal-insulator transition in RuAs.Comment: 10 pages, 10 figure

交通外傷における救急隊の現場滞在時間に関連する要因とその地域差についての検討

Background: The outcome of road traffic injury (RTI) is determined by duration of prehospital time, patient’s demographics, and the type of injury and its mechanism. During the emergency medical service (EMS) prehospital time interval, on-scene time should be minimized for early treatment. This study aimed to examine the factors influencing on-scene EMS time among RTI patients. Methods: We evaluated 19,141 cases of traffic trauma recorded between April 2014 and March 2020 in the EMS database of the Nara Wide Area Fire Department and the prehospital database of the emergency Medical Alliance for Total Coordination of Healthcare (e-MATCH). To examine the association of the number of EMS phone calls until hospital acceptance, age ≥65 years, high-risk injury, vital signs, holiday, and nighttime (0:00–8:00) with on-scene time, a generalized linear mixed model with random effects for four study regions was conducted. Results: EMS phone calls were the biggest factor, accounting for 5.69 minutes per call, and high-risk injury accounted for an additional 2.78 minutes. Holiday, nighttime, and age ≥65 years were also associated with increased on-scene time, but there were no significant vital sign variables for on-scene time, except for the level of consciousness. Regional differences were also noted based on random effects, with a maximum difference of 2 minutes among regions. Conclusions: The number of EMS phone calls until hospital acceptance was the most significant influencing factor in reducing on-scene time, and high-risk injury accounted for up to an additional 2.78 minutes. Considering these factors, including regional differences, can help improve the regional EMS policies and outcomes of RTI patients.博士（医学）・甲第880号・令和5年3月15

粘土地盤の破壊問題への弾・粘塑性構成式の適用

金沢大学工学部強度異方性を含む破壊条件式を用いた、各種の室内・原位置試験によって得られる強度定数を理論的に誘導した.特に、比較的経済的であるにもかかわらず、単に理論的裏付けが充分でないという理由で従来実務的な設計業務に使われることが少なかった等体積一面せん断試験とベーン試験・をとりあげ、せん断にともなう複雑な変形機構・間隙水圧発生機構・強度異方性の発揮機構を理論的に誘導した.このような純粋に理論的な考察に加えて、理論上の結論を検証するための数値解析手法を開発した.通常の有限要素法では破壊の問題をとりあつかうことができないため、特にそのために特殊な数値解析技術をとり込んだ極限解析用有限要素法を開発した.さらに、3次元的な現象をもとりあつかえるようにするため、スーパー・コンピュータによる3次元有限要素プログラムを作成した.これらの有限要素プログラムは、いずれも弾・粘塑性構成式をその基盤におき、土/水連成解析のための一般理論をつり合い式弱形式から導き直したところ、従来のサンドゥ-流・クリスチャン流といって互いに対立していた.2つの学派の所論が実は更に広い範囲の理論体系の中では互いに対立するものではなく特定の仮定に対応した一つの変形であるにすぎないことが判明した.この結果、従来とくらべてはるかに高度なアイソ・パラメトリック要素も混乱なく使いこなすことが可能になった.このようにして開発したいくつかの有限要素プログラムを用いて、実験結果の解釈を試みたところ、おおむね満足すべく結が得られたので、学術雑誌や学会講演会等で発表した.In this research project we have derived the strength parameters to be obtained from various kind of laboratory and field tests on clay. The basic idea is in the development of an elastic-viscoplastic constitutive model of incremental type. Especially we have paid attention in analysing the strength parameters to be obtained from the constant-volume-shear-boxtests and the field vane tests both of which are relatively inexpensive and yet are not widely used the in engineering practice for a reason that their theoretical backgrounds are not well-established. In addition to the purely theretical derivation of the strength parameters, we have developed computer programs to simulate the 3-dimensional soil/water coupling problems associated with the failure of clay. This FEM program requires a super-computer to solve the problems. By using the FEM program developed for 3-D soil/water coupling problems based on an elasto-viscoplastic constitutive model, constant-volume-shear-box tests and field vane tests are successfully simulated. The results are in good accordance with the tests on various kind of clays collected from over this country.研究課題/領域番号:06650533, 研究期間(年度):1994 – 1995出典：研究課題「粘土地盤の破壊問題への弾・粘塑性構成式の適用」課題番号06650533（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-06650533/066505331995kenkyu_seika_hokoku_gaiyo/）を加工して作

1軸試験データの有効利用法-応力解放・乱れを含んだqu値の力学的解釈に基づく補正-

金沢大学工学部1軸試験にともなうサンプリング・トリミング・テスティングの各プロセスで発生する試料中の有効応力変化を日本各地から集めた不攪乱粘土試料に対して追跡し、その結果をまとめた。そのうえで、軟弱粘土が破壊時にすべり線上で発揮する非排水強度のより深い理解を得るべく一連の研究をとりおこない、理論上妥当と思われる非排水強度の平均値を計算した。これと1軸強度に関する研究成果を組み合わせることにより、現在日本でおこなわれている設計法の妥当性とその限界を求めた。得られた結果は24箇所で発生した軟弱粘土の破壊例と比較照合したところ、両者は高い斉合性を示した。得られた結論は(1)乱れや応力解放は軟弱粘土の破壊時の安全率に換算して0.1程度であること。(2)軟弱粘土の破壊に対する施工速度の影響が安全等に換算して0.2程度であり、むしろ施工法の選択に注意を払うべきこと。(3)1軸強度を利用するに当って用いるべき補正係数を粘土の塑性指数の関数として得たこと。である。以上の成果により1軸試験の力学的意味がより明確になだ。近年、特に北米を中心とした研究者の中で、1軸強度の信頼性を疑問視する声が高くなってきている。その論拠はサンプリングによる試料の乱れ、応力解放、試験前および試験中の不完全な非排水条件、なかんずく、せん断試験中の有効応力状態が不明であることに置かれている。このような批判が、各国の自然滞積粘土の地質学的履歴の違いと、各国で実施されているサンプリング技術・および試験技術のレベル差を無視してまで拡張論議されることを防ぐうえで、本研究の結果は役に立ちうると考える。Effective stress state of "undisturbed samples" collected from all over japan was investigated aiming at estimating the residual effective stress in the samples after experiencing sampling, trimming and being ready to be subjected to unconfined compression tests. The undrained strength mobilized along the slip circles was theoreticall derived. The average undrained strength along the slip circle being compared with the corrected unconfined compression strength indicated the appropriateness and the limitation of the usage of unconfined compression strength in the stability analysis of soft clay foundations. The backanalysis of 24 case histories of actual failure of soft clay showed a reasonable agreement with the results obtained from the investigation on unconfined compression strength. the conclusions are as follows:1. The effect of sample disturbance and stress release corresponds to within 0.1 in terms of the factor of safety.2. The effect of loading rate in the field corresponds to about 0.2 in terms of the factor of safety. This indicates that the selection of construction method and construction sequence is more influencial to the stability of soft foundations rather than the degree of sample disturbance is.3. The correction factor to be multiplied with the experimentally obtained unconfined compression strength in analysing the stability of soft clays is derived as a function of the plasticity index.研究課題/領域番号:62850092, 研究期間(年度):1987 – 1988出典：研究課題「1軸試験データの有効利用法-応力解放・乱れを含んだqu値の力学的解釈に基づく補正-」課題番号62850092（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-62850092/628500921988kenkyu_seika_hokoku_gaiyo/）を加工して作

白山山系の背梁を形づくる巨大屋根の超大規模スベリ・崩壊の3次元岩・水連成安定解析

金沢大学工学部1ミリから2センチぐらいのごくうすいスベリ粘土を間に挟んだかたちの亀裂が岩盤の中に多数存在する.かなり多くの山岳崩壊がこう言った弱面に沿って生じるスベリである.一つのスベリ事例に対して,弱面が数十個またはそれ以上存在するのが普通である.したがってすべり落ちてくる岩塊が,どの弱面に沿ってすべってくるかを予測するためには,かなり複雑な3次元幾何学を必要とする.山そのもののかたちも複雑な3次元的形状を持っているから,これを数値的とりあつかうには、それなりの容量を持ったコンピュータを必要とする.たとえば本研究の解析対象のひとつである白山甚之助谷左岸で過去に発生したスベリの解析には,スベリ岩体を含む解析領域を1億2500万個の直方体の集合に置き換えている.このように,概念自体は単純であるが,取り扱わなければならない対象の3次元的な形態が極めて複雑であるから,特殊な工夫を凝らした3次元岩・水連成安定解析用プログラムを作成した.プログラムには,岩体の自重にともなう力のつり合いだけでなく山の中での地下水の動きをできるだけ現実に近い形でシミュレーションし,地下水が岩体に作用する水圧おもつり合いに取り入れた.こうして作成した解析用プログラムにより,いくつかの山岳崩壊事例を実際に解析してみた.解析に先立って必要となるのは,弱面にはさまっているうすい粘土の強度である.本研究では現場で採取したスベリ粘土を一面せん断試験機で等体積せん断に供した.試験法法に特殊な工夫をこらし,このようなうすい粘土のせん断試験を実施すると共に,一面せん断試験そのものの力学的な意義づけをするための理論的研究も実施した.以上の結果,白山で発生している巨大な山岳崩壊の一部を,実際の現象と充分に斉合したかたちで解析することができたThe bodies of mountains are made of rocks which contain a number of cracks with thin layrs of clay. Many of the mountain collapse are triggered by the increase in the water pressure acting on such planes of separation in the rock mass. In order to analyze the mountain collapse, it is needed a computer program which deals with a three dimensional configuration of the rock mass containing a number of plane of separation. In this research project, we have developed a computer program designed for this purpose and apply the program to analyze the colssal collapse of Mt.Hakusan (The White Mountain, 2703m). For a purpose of calibration, many cases of mountain collapse mainly experienced in Noto area where rock materials are extremely weak are analyzed by the developed program. The results of these trial analyzes are basically satisfactory. One of the input data needed in the analysys is the stength of the thin clay material resting in the gap of the planes of separation. We have successfully taken undisturbed samples of thin clay and tested then in a shear box under conditions of constant volume. How to take the samples and how to test them are also the useful harvest of this research project.研究課題/領域番号:06555137, 研究期間(年度):1994 – 1995出典：研究課題「白山山系の背梁を形づくる巨大屋根の超大規模スベリ・崩壊の3次元岩・水連成安定解析」課題番号06555137（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-06555137/065551371995kenkyu_seika_hokoku_gaiyo/）を加工して作