Demolition of Reinforced Concrete by Steam Pressure Cracking System

The authors developed an environment-friendly demolition mechanical system for a large reinforced concrete structure for an actual site. The steam pressure cracking agent (SPC, non-explosive) is a method that can safely and quickly separate concrete because it produces lesser vibration and sound than the blasting method, which uses explosives. The authors showed that the direction of cracking can be controlled by an induction hole. The principle of control is that the elastic wave of the compression stress generated from the SPC reaction changes to a tensile elastic wave at the induction hole, which initiates a crack. Furthermore, in the SPC method, a large amount of concrete powder generated by the explosion method was not produced, and there was no risk of secondary contamination by fine concrete powder. The area over which the crack propagated depends on the energy generated from the SPC. The relationship between the two is linear. For reinforced concrete, the energy of the SPC is used for both the destructive energy of the concrete and the energy of the cutting of the reinforcing steel bar, which quickly breaks with low energy. By applying an SPC to dismantle large reinforced concrete structures, controlled cracking can be achieved safely and quickly without any environmental pollution. A fracturing method using a SPC is an effective method for the decommissioning of nuclear power plants and the dismantling of concrete structures. In this report, we report a remote drilling system that can be used to remotely install loading holes and guiding holes for the SPC and perform effective controlled fracturing

Elastic Wave Property of Concrete Decomposed by Steam Pressure Cracking Agent

A steam pressure cracking (SPC) agent is a method that can dismantle concrete safely and quickly. In previous studies, the authors showed that the direction of the crack could be controlled by the tensile stress at the induction holes and not by the compressive stress at the SPC hole. We demonstrate that the compression elastic wave changes to a tensile wave when the wave is reflected at the free surface of the induction hole. We also examined the properties of the concrete by developing an elastic wave measuring system that is difficult to break down even in high-temperature, wet, and radiation environment. The elastic wave velocity change in the four concrete types was less than 4%. It was found that the standard deviation value, σ, changed four times. Therefore, it is possible to determine the deterioration of the internal structure of concrete using the standard deviation value σ, which indicates the dispersion of the elastic wave velocity

Controlled Cracking of Large Size Concrete Structures by a Steam Pressure Cracking Agent

The dismantling of large concrete structures causes environmental pollution due to the dispersion of polluted micro-particles. The purpose of this study is to develop an environmentally friendly demolition method. Steam pressure cracking (SPC) is a method that can safely and quickly separate concrete because there is less vibration compared to the explosion method. To date, the authors have shown that the direction of cracking in a small sample can be controlled by an induction hole. The principle of control is that the elastic wave of compression stress generated from the SPC reaction changes to a tensile elastic wave at the induction hole, and a crack is initiated. In this study, it was shown that the direction of crack propagation can be controlled by using induction holes in large concrete structures that are 1m on each side. Further, in the SPC method, the large amount of concrete powder generated by the explosion method is not produced, and there is no risk of secondary contamination by fine concrete powder. It was also possible to separate small pieces from the end face of the large concrete by SPC and induction holes. The area over which the crack propagated depends on the energy generated from the SPC agent, and the relationship was linear. By applying an SPC agent to dismantling large concrete structures, we can achieve controlled cracking safely and quickly without any environmental pollution.&nbsp

Cutting of Diamond Substrate Using Fixed Diamond Grain Saw Wire

This study demonstrates that a single-crystal diamond substrate can be cut along designed lines using the diamond-saw-wire cutting method. We developed an original saw-wire fixed diamond-grain using a bronze solder with a high melting temperature. We created a unique product machine system with a high vacuum furnace and a bronze solder that contains a metallic compound. The diamond cutting mechanism employed in this study is based on the mild wear phenomenon, owing to the friction between the diamond surfaces. A linear relationship between the cutting length and wire feed distance was observed. The relationship can be approximated as y = 0.3622x, where y (mu m) is the cutting depth and x (km) is the wire feed distance. The life of the saw-wire was longer than that of the 6000 km wire feed distance and was tested by reciprocating an 8-m short wire at a speed, tension, and cutting force of 150 m/min, 1 N, and 0.2 N, respectively. A single crystal diamond substrate could be cut along the designed line, which was more than 2 mm long. The cutting speed was maintained constant at 0.36 mu m/km

Degradation of Mutant Protein Aggregates within the Endoplasmic Reticulum of Vasopressin Neurons

Misfolded or unfolded proteins in the ER are said to be degraded only after translocation or isolation from the ER. Here, we describe a mechanism by which mutant proteins are degraded within the ER. Aggregates of mutant arginine vasopressin (AVP) precursor were confined to ER-associated compartments (ERACs) connected to the ER in AVP neurons of a mouse model of familial neurohypophysial diabetes insipidus. The ERACs were enclosed by membranes, an ER chaperone and marker protein of phagophores and autophagosomes were expressed around the aggregates, and lysosomes fused with the ERACs. Moreover, lysosome-related molecules were present within the ERACs, and aggregate degradation within the ERACs was dependent on autophagic-lysosomal activity. Thus, we demonstrate that protein aggregates can be degraded by autophagic-lysosomal machinery within specialized compartments of the ER

Elastic Wave Property of Concrete Decomposed by Steam Pressure Cracking Agent

A steam pressure cracking (SPC) agent is a method that can dismantle concrete safely and quickly. In previous studies, the authors showed that the direction of the crack could be controlled by the tensile stress at the induction holes and not by the compressive stress at the SPC hole. We demonstrate that the compression elastic wave changes to a tensile wave when the wave is reflected at the free surface of the induction hole. We also examined the properties of the concrete by developing an elastic wave measuring system that is difficult to break down even in high-temperature, wet, and radiation environment. The elastic wave velocity change in the four concrete types was less than 4%. It was found that the standard deviation value, σ, changed four times. Therefore, it is possible to determine the deterioration of the internal structure of concrete using the standard deviation value σ, which indicates the dispersion of the elastic wave velocity

Complexity of finding dense subgraphs

The k-f(k) dense subgraph problem((k; f(k))-DSP) asks whether there is a k-vertex subgraph of a given graph G which has at least f(k) edges. When f(k)=k(k − 1)=2, (k; f(k))-DSP is equivalent to the well-known k-clique problem. The main purpose of this paper is to discuss the problem of nding slightly dense subgraphs. Note that f(k) is about k 2 for the k-clique problem. It is shown that (k; f(k))-DSP remains NP-complete for f(k) = (k 1+) where may be any constant such that 0 ¡ ¡1. It is also NP-complete for “relatively ” slightly-dense subgraphs, i.e., (k; f(k))-DSP is NP-complete for f(k)=ek 2 =v 2 (1+O(v −1)), where v is the number of G’s vertices and e is the number of G’s edges. This condition is quite tight because the answer to (k; f(k))-DSP is always yes for f(k)=ek 2 =v 2 (1 − (v − k)=(vk − k)) that is the average number of edges in a subgraph of k vertices. Also, we show that the hardness of (k; f(k))-DSP remains for regular graphs: (k; f(k))-DSP is NP-complete for (v 1)-regular graphs if f(k) = (k 1+ 2

Application of traditional herbal medicines to suppress the reversion of polio vaccine viruses to the neurovirulent genotype

Background　The oral poliovirus vaccine (OPV) is regarded as one of the most effective and safest vaccines. However, some paralytic cases have been reported among vaccinees and individuals who have been in contact with vaccinees, because vaccine viruses undergo neurovirulent reversion during repeated replication in the alimentary tract. Moreover, the revertants are excreted with the feces into the environment, and the viruses have caused epidemics of poliomyelitis in the world. Objective　We have reported that Ninjin'yoeito suppressed the reversion of polio vaccine viruses. In this study, to clarify the herbal constituent which takes part in the suppressive effect, we investigated the effect of Ninjinto, which is composed of simpler herbal constituents than Ninjin'yoeito, and of the individual herbal constituents in Ninjinto. Methods　Polio vaccine viruses were serially passaged three times in the presence of herbal medicines in cells derived from the human alimentary tract. The reversion of the passaged viruses was analyzed by the MAPREC and non-RI-modified MAPREC method, designed to estimate the ratio of revertants in a virus population. Results　It was shown that Ninjinto suppressed the reversion of polio vaccine viruses. Although Ginseng Radix and Glycyrrhizae Radix (common herbal constituents in Ninjinto and Ninjin'yoeito) did not show the suppressive effect, the mixture of both herbal constituents was a little inhibitory in regard to the reversion of the viruses. Conclusion　It is quite likely that the suppressive effect on reversion is not a simple process. A complicated interaction of some components of the herbal constituents might take part in the effect. It is expected that traditional herbal medicines like Ninjinto and Ninjin'yoeito will contribute to solving the problems of OPV though further analyses of the herbal constituents and their components are necessary to clarify the mechanism of the suppressive effect.背景　経口生ポリオワクチン(OPV) は、安全性と有効性が高いワクチンである。 しかし、その一方、極めて低い頻度ではあるが、ワクチン被接種者あるいは被接種者に接触した人に、ポリオ(急性灰白髄炎)の発症例が報告されている。これは弱毒ワクチンウイルスが、人の消化管細胞で増殖する過程において、毒力復帰変異を起こすことに起因すると考えられている。 更に、その変異ウイルスが、糞便とともに環境中に排泄されることで、ポリオの新たな流行を世界各地で引き起こし、大きな問題となっている。目的　我々は、和漢薬の一つである人参養栄湯エキスに、ポリオワクチンウイルスの毒力復帰変異に対する抑制効果が見られることを既に報告した。本研究では、人参養栄湯の中の、どのような生薬成分がこの抑制効果に関与しているかを調べるために、人参養栄湯よりも混合(構成)生薬の種類が極端に少ない人参湯エキスについて、更に、人参養栄湯と人参湯の共通構成生薬である人参と甘草の両生薬エキスについて、毒力復帰変異抑制効果の解析を行った。方法　ポリオワクチンウイルスをヒト消化管由来細胞を用いて、人参養栄湯エキス、人参湯エキス、あるいは上記2種の生薬エキスをそれぞれ至敵濃度含有する培地中で、3代継代培養を行った。これら継代ウイルスの毒力復帰変異について、遺伝子レベルでウイルスの毒力（神経毒力）の強さを測定できるMAPREC法、およびMAPREC法の一部を改変した非RI-MAPREC法で解析した。結果　人参湯エキスにも人参養栄湯エキスに近い毒力復帰変異抑制効果が認められたが、人参と甘草の両生薬エキスについては、ほとんど抑制効果は見られなかった。しかし、両生薬エキスを混合して用いることで、若干の抑制効果が認められた。結論　人参養栄湯や人参湯によるポリオワクチンウイルスの毒力復帰変異抑制効果は、単純にどれか1種類の生薬成分によって起きるものではなく、複数の成分による複雑な相互作用が関与している可能性が示唆された。どのような生薬成分が、どのようなメカニズムで毒力復帰変異の抑制を起こすのか、解析を行う必要が残されているが、人参養栄湯や人参湯のような和漢薬は、OPVがもつ問題の解決に大きく貢献することが期待される