Institute of Disaster Prevention

A self-assembled spongelike (S) ultralight (<italic>ρ</italic> ≈ 140 mg cm⁻³) aerogel was fabricated through polypyrrole (PPy) and reduced graphene oxide (RGO).

Seismic tomography revealed a low seismic velocity (-5%) and high Poisson's ratio (+6%) anomaly covering about 300 square kilometers at the hypocenter of the 17 January 1995, magnitude 7.2, Kobe earthquake in Japan. This anomaly may be due to an overpressurized, fluid-filled, fractured rock matrix that contributed to the initiation of the Kobe earthquake.

The confirmed and suspected cases of the 2019 novel coronavirus disease (COVID-19) have increased not only in Wuhan, Hubei Province, but also China and the world. Enormous demand for handling the COVID-19 outbreak challenged both the health care personnel and the medical supply system. In West China Hospital, emergency department (ED) undertook the mission of clinical reception, primary diagnosis, and interim treatment for the suspected cases of COVID-19. The pathogen of COVID-19, severe acute respiratory syndrome coronavirus 2, was confirmed to have human-to-human transmission.1 Therefore, COVID-19 has expanded the infection risk from Wuhan to cities throughout China and even the world via case transportation.2 Providing qualified personal protection equipment (PPE) to health care personnel plays an essential role in avoiding occupational exposure and infection. U.S. Centers for Disease Control and Prevention for COVID-19 infection control of health care personnel recommended gloves, gowns, respiratory protection, and eye protection as standardized PPE.3 However, protective clothing, N95 respirators, and goggles are not commonly used in clinical practice and hence are not in bulk stock. This brief report aims to present our interim hospital management measures on the health care personnel protection in West China Hospital under the condition of intense workload and PPE supply shortage after the outbreak of COVID-19. Emergency- and disaster-preparedness was an important issue and a global problem. Most hospitals could not maintain their routine work for a week due to the disaster-related resource shortage.5 A previous review highlighted the challenge of the emergency ordering of standardized PPE supply.6 The hospital invested greater efforts to establish an emergency management system based on the anticipated hazard.7 However, the unpredictable epidemic rendered the interim PPE preparedness impossible, especially for less-used PPE, protective clothing, and N95 respirators in daily work. It might be more practical to prepare a flexible hospital contingency plan than abundant PPE preparedness. Our hospital adopted interim measures, including online consultation, region separation, and epidemic priority, to alleviate the pressure in the clinical work, reduce the cross-infection, and strengthen the protection of high-risk staff. Our hospital held the “zero infection” record, which was far lower than the simultaneous outside-Hubei mean level of 3.4% in late January.8 The zero infection indicated the flexibility and validity of our interim hospital management strategy. However, there were still some limitations. First, the supply protocol compromised the health protection of low-risk personnel without standardized PPE. Second, the interim management strategies could not resist large-scale outbreak and long-term PPE shortage. Nevertheless, our management strategies, as a temporary emergency plan, created the biggest benefits of extremely limited resources to meet the emergency need. The long-term solution should be a sustainable supply chain. Fortunately, the government of China recovered the PPE production supply in February, which alleviated the supply shortage significantly. In conclusion, the hospital emergency management plan of West China Hospital could alleviate the ED workload, protect health care personnel, and control the cross-infection during the COVID-19 epidemic. We advocate that every hospital should create the contingency plan suited to their conditions. We acknowledge the colleagues at Emergency Department of West China Hospital and also all the colleagues combating COVID-19.

Water industries worldwide consider coagulation/flocculation to be one of the major treatment methods for improving the overall efficiency and cost effectiveness of water and wastewater treatment. Enhancing the coagulation process is currently a popular research topic. In this review article, the latest developments in enhanced coagulation are summarized. In addition, the mechanisms of enhanced coagulation and the effect of process parameters on processing efficiency are discussed from the perspective of ballast-enhanced coagulation, preoxidation, ultrasound, and composite coagulants. Finally, improvements and new directions for enhanced coagulation are proposed.

Fifty-eight non-professional fire fighters, 91% of all firefighters from different industries who participated in a hotel fire rescue operation, were investigated by means of a structured self-report questionnaire about their stress experience during and after the rescue action. Together with 57 professional fire fighters, they participated in rescuing hotel guests confined for as much as three hours in a 12 storeyed hotel building on fire. Fourteen persons (11%) died, 114 guests survived. Forty-seven percent of the non-professional fire fighters reported that the disaster experience was the worst they had ever experienced. Even so, 80% thought that they had coped with the job well to fairly well and for as many as 66% the rescue action represented something positive to them in retrospect. Ten percent claimed that stress reactions disturbed them in executing effective rescue work. Fifty-eight percent maintained that more preparation and training could have improved their effort. Fire fighters with previous practical experience seemed to "digest" the disaster experience more easily than inexperienced fire fighters as measured by the Impact of Event Scale. High level of competence and opportunity for debriefing as well as disaster characteristics are discussed as factors explaining the favourable coping with extreme stress.

Coal and coalbed methane (CBM) coordinated exploitation is a key technology for the safe exploitation of both resources. However, existing studies lack the quantification and evaluation of the degree of coordination between coal mining and coalbed methane extraction. In this study, the concept of coal and coalbed methane coupling coordinated exploitation was proposed, and the corresponding evaluation model was established using the Bayesian principle. On this basis, the objective function of coal and coalbed methane coordinated exploitation deployment was established, and the optimal deployment was determined through a cuckoo search. The results show that clarifying the coupling coordinated level of coal and coalbed methane resource exploitation in coal mines is conducive to adjusting the deployment plan in advance. The case study results show that the evaluation and intelligent deployment method proposed in this paper can effectively evaluate the coupling coordinated level of coal and coalbed methane resource exploitation and intelligently optimize the deployment of coal mine operations. The optimization results demonstrate that the safe and efficient exploitation of coal and CBM resources is promoted, and coal mining and coalbed methane extraction processes show greater cooperation. The observations and findings of this study provide a critical reference for coal mine resource exploitation in the future.

First report on the excellent electromagnetic absorption and electromagnetic interference shielding performances of helical conducting polymer nano-structures.

Nine months post-disaster, 134 rescuers involved in an off-shore oil rig disaster were investigated by using a structured self report questionnaire to chart their experience of coping with disaster impact stressors and their mental and physical health 9 months after the disaster. Of the 134 rescuers, 24 were categorized as professional rescuers, 101 as non-professionals and 9 could not be classified. Of the 212 victims, all oil rig workers, 89 (42%) were rescued. Seventy-six percent of the rescuers reported they had been exposed to danger during the rescue operation, and 62% found the experience to be the worst ever. Eighty to ninety percent felt they had coped fairly well with the task, and severely disturbed coping was reported to be below 10% for decision-making, ability to judge risk, capacity to function as leader, and finally ability to cooperate and act efficiently. For the non-professionals, severe disturbance in ability to plan before acting was reported by 10% and moderate disturbance was reported by 38%. The frequency of emotional stress reactions during the rescue work can be assessed from the fact that 64% to 52% reported discouragement, restlessness, uncertainty, anxiety and irritation. The stressors inherent in this type of disaster seem to satisfy the DSM III stressor criterion for post-traumatic stress disorder. Nine months after the disaster 24% reported their mental health to be poor due to the disaster impact, and only the most experienced rescuers had a low health risk compared to the others.

Graphene oxide and zinc oxide nanoparticles have formed a three-dimensional nanocomposite with a high performance of electromagnetic absorption <italic>via</italic> a hydrothermal process. UV-irradiation removed the remaining oxygen functional groups from the skeleton of the reduced graphene oxide.

Road pavement cracks automated detection is one of the key factors to evaluate the road distress quality, and it is a difficult issue for the construction of intelligent maintenance systems. However, pavement cracks automated detection has been a challenging task, including strong nonuniformity, complex topology, and strong noise-like problems in the crack images, and so on. To address these challenges, we propose the CrackSeg—an end-to-end trainable deep convolutional neural network for pavement crack detection, which is effective in achieving pixel-level, and automated detection via high-level features. In this work, we introduce a novel multiscale dilated convolutional module that can learn rich deep convolutional features, making the crack features acquired under a complex background more discriminant. Moreover, in the upsampling module process, the high spatial resolution features of the shallow network are fused to obtain more refined pixel-level pavement crack detection results. We train and evaluate the CrackSeg net on our CrackDataset, the experimental results prove that the CrackSeg achieves high performance with a precision of 98.00%, recall of 97.85%, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi>F</mml:mi></mml:math>-score of 97.92%, and a mIoU of 73.53%. Compared with other state-of-the-art methods, the CrackSeg performs more efficiently, and robustly for automated pavement crack detection.

Non-response and psychological resistance, i.e. degree of unwillingness to undergo the primary examination (screening), and its implications for estimation of PTSD prevalences was measured in a longitudinal study of 246 employees exposed to an industrial disaster (explosion/fire). Resistance including refusal, was measured by counting the number of contacts needed in the calling-in procedure to secure cooperation. Resistance to the primary examination related to severity of exposure (24.2% in the high exposure versus 6.8% in the medium exposure and 4.2% in the low exposure group). If those who initially resisted had been lost to the 7 month follow-up the total response rate would have been 82.8%, with an estimated frequency of high PTSS scores of 15. By increasing the response rate to 100%, the true prevalence of high PTSS scores increase to 22.4%. The initial resistance related strongly (P less than 0.001) to the severity of outcome at 7 months. The potential loss to the follow-up would have included 42% of the PTSD cases, and 64% of the severe PTSD cases would have fallen out, resulting in distorted prevalence rates of PTSD. The high potential loss to follow-up in the high exposure category would reduce the predictor value of belonging to that exposure group. The initial resistance in many who later developed PTSD was found to relate to the psychological defences such as avoidance against the re-experiences in the acute post-traumatic stress syndrome. For traumatic stress studies on the after-effects of shock traumas the implication of findings is that response rates need to be high. For primary and secondary prevention the implication may be that early outreach must be very active.

Abstract The design and construction of an undrained ring shear apparatus, which was newly developed at Disaster Prevention Research Institute, Kyoto University, are presented in detail. This apparatus is suited for undrained shear tests under all types of loading, and enables observing the undrained shear behavior of soils in high-speed motion (maximum rotating speed 2.24 m/s) to an endless displacement level. Using rubber edges and a gap control system, leakage of pore water was effectively prevented, and the friction of rubber edges was controlled with high credibility during shearing. For undrained shearing tests on sand, the related experimental procedures are introduced and the undrained shear behavior of sand in ring shear test is presented. Test results showed that high pore water pressures could be built up in both loose and dense sands, given the shear displacement is great enough.

Girth weld cracking is one of the main failure modes in oil and gas pipelines; girth weld cracking inspection has great economic and social significance for the intrinsic safety of pipelines. This paper introduces the typical girth weld defects of oil and gas pipelines and the common nondestructive testing methods, and systematically generalizes the progress in the studies on technical principles, signal analysis, defect sizing method and inspection reliability, etc., of magnetic flux leakage (MFL) inspection, liquid ultrasonic inspection, electromagnetic acoustic transducer (EMAT) inspection and remote field eddy current (RFDC) inspection for oil and gas pipeline girth weld defects. Additionally, it introduces the new technologies for composite ultrasonic, laser ultrasonic, and magnetostriction inspection, and provides reference for development and application of oil and gas pipeline girth weld defect in-line inspection technology.

Abstract Hydrologic responses to earthquakes and their mechanisms have been widely studied. Some responses have been attributed to increases in the vertical permeability. However, basic questions remain: How do increases in the vertical permeability occur? How frequently do they occur? Is there a quantitative measure for detecting the occurrence of aquitard breaching? We try to answer these questions by examining data from a dense network of ∼50 monitoring stations of clustered wells in a sedimentary basin near the epicenter of the 1999 M7.6 Chi‐Chi earthquake in western Taiwan. While most stations show evidence that confined aquifers remained confined after the earthquake, about 10% of the stations show evidence of coseismic breaching of aquitards, creating vertical permeability as high as that of aquifers. The water levels in wells without evidence of coseismic breaching of aquitards show tidal responses similar to that of a confined aquifer before and after the earthquake. Those wells with evidence of coseismic breaching of aquitards, on the other hand, show distinctly different postseismic tidal response. Furthermore, the postseismic tidal response of different aquifers became strikingly similar, suggesting that the aquifers became hydraulically connected and the connection was maintained many months thereafter. Breaching of aquitards by large earthquakes has significant implications for a number of societal issues such as the safety of water resources, the security of underground waste repositories, and the production of oil and gas. The method demonstrated here may be used for detecting the occurrence of aquitard breaching by large earthquakes in other seismically active areas.

Since train vehicle accidents caused by strong winds sometimes occur in Japan, Japan railway companies requested the Railway Technical Research Institute to promote research and development of preventive measures. To respond to this request, we have investigated aerodynamic forces acting on train vehicles and characteristics of strong winds and proposed several software and hardware preventive measures. This report presents the results of our investigation and the measures adopted in Japan Railway lines.

Pavement crack detection and characterization is a fundamental part of road intelligent maintenance systems. Due to the high non-uniformity of cracks, topological complexity, and similar noise from crack texture, the challenge arises in this domain with automated crack detection and classification in a complex environment. In this work, an overarching framework for a universal and robust automatic method that simultaneously characterizes the type of crack and its severity level was developed. For crack detection, we propose a novel and efficient crack detection network that captures the crack context information by establishing a multiscale dilated convolution module. On this foundation, an attention mechanism is introduced to further refine the high-level features. Moreover, the rich features at different levels are fused in an upsampling module to generate more detailed crack detection results. For crack classification, a novel characterization algorithm is developed to classify the type of crack after detection. The crack segment branches are then merged and classified into four types: transversal, longitudinal, block, and alligator; the severity levels of cracks are assessed by calculating the average width and distance between the crack branches. The proposed crack detection method effectively detects crack information in a complex environment, and achieves the current state-of-the-art accuracy. Compared to manual classification results, the classification accuracy of transversal and longitudinal cracks is higher than 95%, and the classification accuracy of block and alligator is above 86%.

Abstract As the first part of non‐structural component test series, interior drywall partitions are selected for an experimental program. This test series will cover non‐structural components that are significant in the economic losses in buildings subjected to seismic loading, namely interior drywall partitions, exterior cladding and window glasses, and ceilings. Four full‐scale drywall partitions with light‐gage steel stud framing were tested to observe damage in cyclic loading conditions. Effects of a door and an intersecting wall on the behaviour of drywall partition are studied. Damage was concentrated to perimeter regions where gypsum boards made contacts with ceiling, floor, or columns. Dynamic loading did not amplify the damage on a drywall partition over the damage observed from the quasi‐static test. Damage–repair cost relationships show that the repair cost reaches almost the initial cost under 2% radian interstorey drift. Copyright © 2006 John Wiley &amp; Sons, Ltd.

Electromagnetic pollution is rising all over the world. Compared with electromagnetic waves reflection, electromagnetic absorption (EA) is a better choice to balance electromagnetic applications and human health. The highly conductive networks in composites, as well as in species, and the intensity of defect polarization are the most important factors to improving the EA performance of a dielectric material. In this study, an in situ one-pot hydrothermal growth of MoS2 layers on reduced graphene oxide (RGO) surfaces was developed for the synthesis of RGO/MoS2 nanosheets. With a filler loading ratio of 20 wt%, the composite of the RGO/MoS2 nanosheets could build conductive networks and exhibited an effective EA bandwidth (lower than -10 dB) of 5.7 GHz and a minimum reflection loss (RL) of -60 dB. The results revealed that the as-prepared RGO/MoS2 nanosheets are promising EA materials, with broad and strong absorption properties at a low filler loading and low thickness.

A laboratory fire-extinguishing system was applied to investigate the effect of gas-liquid ratio on the fire-extinguishing performance of aqueous film-forming foam (AFFF) in diesel pool fire, and the proposed fire-extinguishing mechanism of AFFF is carefully analyzed. The results show that the AFFF foam possesses the shortest extinguishing time of 42s and lowest foam liquid consumption of 210 g at a gas-liquid ratio of 16, exhibiting the best fire-extinguishing performance. Chemical analysis of AFFF indicates that a proper gas-liquid ratio is beneficial to enhance the expansion ratio and drainage rate of AFFF that affect the cooling and covering effects of foam, thus achieving the optimum fire-extinguishing efficiency. Infrared thermal imaging analysis indicates that the main fire-extinguishing mechanism of AFFF is mainly ascribed to the superior cooling, covering and suffocating effects of foam against the transfer of heat and oxygen, thus effectively preventing the underlying fuel from further combustion.

An eco‐friendly bio‐filler was prepared by reusing of chicken eggshell (CES), and well characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM)‐energy dispersive X‐ray spectroscopy (EDS), X‐ray fluorescence spectrometry (XRF), and thermo‐gravimetric (TG) analysis. The influence of CES on the thermal stability, flame‐retardant, and smoke suppression properties of epoxy‐based traditional intumescent system was investigated by limited oxygen index (LOI), UL 94 test, cone calorimeter test, and TG analysis. The results shows that the incorporation of CES improves the LOI value of the samples, and IFR‐3 with 37 wt% intumescent flame retardant (IFR) and 3 wt% CES exhibits the maximum LOI value of 31.5%. The results from cone calorimeter and smoke density tests reveal that the addition of CES greatly decreases the heat release and smoke production of the samples concomitant with an increase in the residual weight, which is ascribed to the formation of a more compact, thermally stable, and intumescent char against heat and mass transfer during burning. The synergistic effect on fire performance between CES and IFR depends on the content of CES, and an excessive content of CES diminishes this synergistic effect. The TG analysis shows that the intumescent system containing CES exhibits high thermal stability and char‐forming ability. Overall, CES can serve as an environmentally friendly bio‐filler and a promising synergist for intumescent systems. POLYM. COMPOS., 40:2712–2723, 2019. © 2018 Society of Plastics Engineers