Studies of Flexible Barriers Under Debris Flow Impact: An Application to an Alpine Basin

AbstractThe aim of this paper is to analyze the most relevant aspects that influence the interaction between debris flow phenomena and protection barriers. The volume of the debris and its lithological nature are conditioning the barrier size and strength. This system is often complicated by environmental and climate influences that need to be taken into consideration as well; therefore, a correct design of a protection barrier system in an alpine basin is a complex procedure that needs to be rationalized. This paper will concentrate on the barrier dimension design proposing a rational scheme of study of the global problem. The application to an Alpine basin is reported

Application of Low Potential Electric Fields for Improving Slope Stability

AbstractThe aim of this research is the application of low potential direct currents in order to improve slope stability by inducing the reduction of potential swelling and water content, and the precipitation of carbonates in cohesive soil pertaining to a possible sliding surface. Two different types of tests were performed: the first one on small samples and the other one on a physical model reproducing a slope. Main results showing the effectiveness of this application are described

Definition of a new multi-level early warning procedure for landslide risk management

The identification of potentially critical events involving unstable slopes is a major aspect in the field of natural hazards risk mitigation and management. In this framework, Early Warning Systems (EWS) exploiting advanced technologies represent an efficient approach to decrease the risk generated by landslide phenomena, allowing to reduce the possibility of damages and losses of human lives. EWS effectiveness has increased significantly in recent years, thanks to relevant advances in sensing technologies and data processing. In particular, the introduction of innovative monitoring instrumentation featuring automatic procedures and increased performances in terms of sampling rate and accuracy has permitted to develop EWS characterised by a near-real time approach. Among the several aspects involved in the development of a reliable Early Warning System, one of the most important is the ability to minimize the dissemination of false alarms, which should be avoided or identified in advance. The approach proposed in this study represents a new procedure aimed to assess the hazard level posed by a potentially critical event, previously identified by analysing displacement monitoring data. The process is implemented in a near-real time EWS and defines a total of five different hazard levels, on the basis of the results provided by two different models, namely an accelerating trend identification criterion and a failure forecasting model based on the Inverse Velocity Method (IVM). In particular, the forecasting analysis is performed only if the dataset elaborated by the onset-of-acceleration model highlights a potentially critical behaviour, which represents a first alert level. Following levels are determined by different conditions imposed on three parameters featured by the failure forecasting model, i.e. dataset dimension, coefficient of determination R-squared, and number of sensors displaying an accelerating trend. As these criteria get fulfilled, it is assumed that the monitored phenomenon is gradually evolving towards a more critical condition, thus reaching an increasing alert level depending on the analysis results. According to this classification, it is possible to set up for each single threshold a dedicated warning message, which could be automatically issued to authorities responsible of monitoring activities, in order to provide an adequate dissemination of information concerning the ongoing event. Moreover, the proposed procedure allows to customize the alert approach, giving the possibility to issue warning messages only if a certain Level is reached during the analysis

application of innovative monitoring tools for safety and alert procedures in road tunnels

Abstract Tunnels and underground structures are one of the most important components of road and railway networks, especially near urban areas. For this reason, it is particularly important to identify potentially hazardous conditions in order to guarantee the structure's durability and practicability. This paper presents a case study where a seismic event severely damaged a road tunnel located in Central Italy, impairing its accessibility and leading to its closure for safety reasons. Following the damage assessment, and given the importance of this specific structure, it was decided to perform a series of renovation works aimed to restore the tunnel's operability. In this context, an innovative automatic monitoring device, able to measure the structure deformation, was installed in a critical section of the road tunnel. This instrument, called Cir Array, is specifically designed for near-real time monitoring of convergence phenomena and localized deformations inside underground structures, obtaining accurate and reliable results during their operational phase. The instrumentation provided useful information about the structure's conditions, playing a major role into assessing the tunnel's accessibility and safety during the renovation works. Moreover, thanks to its automated and high frequency sampling process, it will allow the implementation of dedicated warning procedures related to the passage of the vehicles inside the tunnel

GROUND TEMPERATURE MONITORING FOR A COAXIAL GEOTHERMAL HEAT EXCHANGERS FIELD: PRACTICAL ASPECTS AND MAIN ISSUES FROM THE FIRST YEAR OF MEASUREMENTS

Plitka, potpovršinska, temperatura (na dubinama plićim od 50 m) nije konstantna, niti u prostoru, niti vremenu. Takve promjene posljedica su utjecaja toplinskih „pulseva” različitoga podrijetla poput Sunčeva, geotermalnoga ili ljudskoga. Točna procjena temperature ključni je čimbenik kod planiranja energetskih sustava temeljenih na plitkoj geotermalnoj energiji. U takvim projektima, temeljenim na izmjenjivačima topline u plitkim bušotinama, potpovršinska je temperatura promjenjivija, što utječe na iznos pridobivanja topline, tj. utiskivanja fluida. Praćenje takvih promjena važno je stoga kod svih projekata toplinskih izmjenjivača vezanih uz plitka geotermalna ležišta. U radu je prikazan praktičan oblik toga, ali i glavni problemi koje je moguće susresti tijekom instaliranja, testiranja ili uporabe potrebne geotermalne opreme. Dan je primjer polja u kojemu je smješteno osam koaksijalnih izmjenjivača topline, 30 metara dugačkih te povezanih s prototipom uređaja dvostruke toplinske crpke (zračne i dubinske).Ground temperature at shallow depth (< 50 m) is not stable, nor in space, neither in time, and its behaviour is the result of superimposition of effects of heat pulses of different origin: solar, geothermal and anthropic. The correct assessment of ground temperature is a crucial point when designing a shallow geothermal energy system. In geothermal closed loop projects, more the borehole heat exchangers are short, more the contribution of the ground temperature variability on the heat exchange is prominent. Monitoring ground temperature can be very useful to correctly understand the behaviour of a shallow geothermal reservoir subjected to heat extraction and/or injection by a ground source heat pump system. The present work illustrates the practical aspects and main issues occurred in the installation, testing and working phases of a monitoring system realised to record ground temperature in a geothermal application. The case study is a field of eight coaxial borehole heat exchangers, 30 m long, connected to a novel prototype of dual source (air and ground) heat pump

Técnicas avanzadas de control de obras: preconvergencia en túneles y barreras dinámicas

Los diseños geotécnicos se basan en hipótesis y aproximaciones no siempre fiables, por lo que las incertidumbres del comportamiento de estructuras geotécnicas suelen ser mayores que las que se dan en otras estructuras de ingeniería. Así, las observaciones in situ y, en particular, la medición de magnitudes físicas específicas son el mejor antídoto para superar las limita-ciones propias de estas obras. En este contexto, el control o monitorización geotécnica se revela como una herramienta básica para el diseño y ejecución de obras en condiciones de seguridad y economía aceptables. En este estudio se presenta la aplicación de sistemas de monitorización de obras basados en sensores tipo MEMS (Micro Electro Mechanical System), de precio asequible y razonablemente precisos, que permiten tomar medidas múltiples con aportes de energía mínimos y pueden transmitir gran cantidad de información en tiempo real. En particular, se presentan dos prototipos de sistemas de control basados en estos sensores. El primero de ellos mide la pre-convergencia en túneles, permitiendo obtener los desplazamientos del terreno en un sondeo situado a la altura del techo de excavación y por delante del frente de la misma, lo que contribuye a identificar en fase temprana posibles problemas de la excavación y correlacionar las medidas con cálculos previos. El segundo monitoriza la respuesta de barreras flexibles para el control de desprendimientos, controlando la inclinación de postes y la elongación de la malla, por lo que permite conocer en tiempo real la situación de la barrera sin acceder a la misma

Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study

: The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p &lt; 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries