150 research outputs found

    New algorithm for water leakages flow through rain screen deficiencies

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    There is a need of more knowledge about the mechanisms of water leakage through façades exposed to driving rain to make reliable risk analyses. Therefore, we have studied it in more detail and the outcome include inter alia a new algorithm. The algorithm is developed for calculation of water leakages through rain screen deficiencies. The algorithm is based on empirical values from many measurements according to standardized test method and validation. Even though the leakage process is very complicated, simple correlations have been shown. The leakages flow rate through deficiencies are mainly limited by the runoff rate and the catch area above the hole and around the hole with dam. Apart from wind pressure as a driving force, the inlet of the holes is often on a higher level than the outlet at the rear of the façade, which creates significant hydrostatic pressure, which can be elevated by impoundment at the obstacle. This is the main reasons to comprehensive water leakages through façades without any wind pressure (pressure equalized façades). If precise information about defects data is not available, there are extensive measurements supporting the following assumption – a realistic leakage flow for a small or invisible spot leakage at a façade detail is presumed to be 0.5 to 2% of the runoff rate per meter of façade width. If there are multiple penetrations or obvious defects in the façade design in combination with the dams, a significantly higher proportion of the runoff flow can leak in

    Stochastic simulation of rain intrusion through small defects due to water rivulet overpressure. Introducing a driving rain leakage potential

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    There is a need of upgrading the old building stock with respect to the thermal insulation of the building envelope and specifically the fa\ue7ades. There are several systems on the market, and some are quite new and innovative. To bring down the cost some of the systems many are based on prefabricated moisture tight insulated units. This means that in case there is moisture tight barrier on the interior side, two moisture tight barriers surround the wall structure. The leakage of driving rain into the structure then represents a major threat to the durability of these systems. This paper investigates the pressure build up in water rivulets running down a fa\ue7ade acting together with the wind pressure. A driving rain leakage potential is introduced. Using real weather data years and Monte Carlo Simulations, the mean and standard deviation of the annual leakage through small hole is estimated. The examples show that the leakage can reach a level 0-0.5 liter/year for a hole with a diameter of 1-2 mm, and 0.5-3 liter/year for a diameter of 3-4 mm

    Risk assessment of joint sealing tape in joints between precast concrete sandwich panels resilient to climate change

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    Lately, a new technical solution, pre-compressed joint sealing tapes in precast concrete sandwich panel facades, has been introduced in Sweden. Although the consequences of performance failure can go far beyond the component, affecting the building, the introduction has gained little attention in terms of risk assessment in the literature and in industry. Instead, reference cases are used as verification without formal evaluation, potentially leading to serial failure. The aim of this paper was to provide guidance on how a design–build contractor should handle this new technical solution. A risk assessment framework using a design–build contractor’s perspective was applied to the case. The framework addresses new technical solutions or adaption to new conditions (e.g., climate change) with the aim of preventing serial failures. Moisture conditions within the joints were simulated using present and future climates, and probabilities of failure were assessed using the Monte Carlo method. The results of the study included identified risks of failure associated with the solution and factors influencing the probability of failure. A main issue was the exposure of the facade to driving rain but also run-off areas and imperfections in the application of the joint sealing tape. Future climate changes affect performance negatively. In conclusion, the new technical solution might be possible to use if draining potential is ensured in all detailed designs and a set of recommendations, including full-scale testing, is provided for the design–build contractor

    New algorithm for water leakages flow through rain screen deficiencies

    Get PDF
    There is a need of more knowledge about the mechanisms of water leakage through fa\ue7ades exposed to driving rain to make reliable risk analyses. Therefore, we have studied it in more detail and the outcome include inter alia a new algorithm. The algorithm is developed for calculation of water leakages through rain screen deficiencies. The algorithm is based on empirical values from many measurements according to standardized test method and validation. Even though the leakage process is very complicated, simple correlations have been shown. The leakages flow rate through deficiencies are mainly limited by the runoff rate and the catch area above the hole and around the hole with dam. Apart from wind pressure as a driving force, the inlet of the holes is often on a higher level than the outlet at the rear of the fa\ue7ade, which creates significant hydrostatic pressure, which can be elevated by impoundment\ua0at the obstacle. This is the main reasons to comprehensive water leakages through fa\ue7ades without any wind pressure (pressure equalized fa\ue7ades). If precise information about defects data is not available, there are extensive measurements supporting the following assumption – a realistic leakage flow for a small or invisible spot leakage at a fa\ue7ade detail is presumed to be 0.5 to 2% of the runoff rate per meter of fa\ue7ade width. If there are multiple penetrations or obvious defects in the fa\ue7ade design in combination with the dams, a significantly higher proportion of the runoff flow can leak in

    Person-centred care compared with standardized care for patients undergoing total hip arthroplasty—a quasi-experimental study

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    BACKGROUND: A common approach to decrease length of stay has been to standardize patient care, for example, by implementing clinical care pathways or creating fast-track organizations. In a recent national report, it was found that Sweden’s healthcare system often fails to anticipate and respond to patients as individuals with particular needs, values and preferences. We compared a standardized care approach to one of person-centred care for patients undergoing total hip replacement surgery. METHODS: A control group (n =138) was consecutively recruited between 20th September 2010 and 1st March 2011 and an intervention group (n =128) between 12th December 2011 and 12th November 2012, both scheduled for total hip replacement. The primary outcome measures were length of stay and physical function at both discharge and 3 months later. RESULTS: The mean length of stay in the control group was 7 days (SD 5.0) compared to 5.3 days in the intervention group (SD 2.2). Physical functional performance, as assessed using activities of daily living, was similar at baseline for both groups. At discharge, 84% in the control group had regained activities of daily living level A vs. 72% in the intervention group. At 3 months after surgery, 88% in the control group had regained their independence vs. 92.5% in the person-centred care group. CONCLUSIONS: Focusing attention on patients as people and including them as partners in healthcare decision-making can result in shorter length of stay. The present study shows that the patients should be the focus and they should be involved as partners

    SandTrap: Securing JavaScript-driven Trigger-Action Platforms

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    Trigger-Action Platforms (TAPs) seamlessly connect a wide variety of otherwise unconnected devices and services, ranging from IoT devices to cloud services and social networks. TAPs raise critical security and privacy concerns because a TAP is effectively a “person-in-the-middle” between trigger and action services. Third-party code, routinely deployed as “apps” on TAPs, further exacerbates these concerns. This paper focuses on JavaScript-driven TAPs. We show that the popular IFTTT and Zapier platforms and an open-source alternative Node-RED are susceptible to attacks ranging from exfiltrating data from unsuspecting users to taking over the entire platform. We report on the changes by the platforms in response to our findings and present an empirical study to assess the implications for Node-RED. Motivated by the need for a secure yet flexible way to integrate third-party JavaScript apps, we propose SandTrap, a novel JavaScript monitor that securely combines the Node.js vm module with fully structural proxy-based two-sided membranes to enforce fine-grained access control policies. To aid developers, SandTrap includes a policy generation mechanism. We instantiate SandTrap to IFTTT, Zapier, and Node-RED and illustrate on a set of benchmarks how SandTrap enforces a variety of policies while incurring a tolerable runtime overhead

    Securing Node-RED Applications

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    Trigger-Action Platforms (TAPs) play a vital role in fulfilling the promise of the Internet of Things (IoT) by seamlessly connecting otherwise unconnected devices and services. While enabling novel and exciting applications across a variety of services, security and privacy issues must be taken into consideration because TAPs essentially act as persons-in-the-middle between trigger and action services. The issue is further aggravated since the triggers and actions on TAPs are mostly provided by third parties extending the trust beyond the platform providers. Node-RED, an open-source JavaScript-driven TAP, provides the opportunity for users to effortlessly employ and link nodes via a graphical user interface. Being built upon Node.js, third-party developers can extend the platform’s functionality through publishing nodes and their wirings, known as flows. This paper proposes an essential model for Node-RED, suitable to reason about nodes and flows, be they benign, vulnerable, or malicious. We expand on attacks discovered in recent work, ranging from exfiltrating data from unsuspecting users to taking over the entire platform by misusing sensitive APIs within nodes. We present a formalization of a runtime monitoring framework for a core language that soundly and transparently enforces fine-grained allowlist policies at module-, API-, value-, and context-level. We introduce the monitoring framework for Node-RED that isolates nodes while permitting them to communicate via well-defined API calls complying with the policy specified for each node

    Ro/SSA autoantibodies directly bind cardiomyocytes, disturb calcium homeostasis, and mediate congenital heart block

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    Congenital heart block develops in fetuses after placental transfer of Ro/SSA autoantibodies from rheumatic mothers. The condition is often fatal and the majority of live-born children require a pacemaker at an early age. The specific antibody that induces the heart block and the mechanism by which it mediates the pathogenic effect have not been elucidated. In this study, we define the cellular mechanism leading to the disease and show that maternal autoantibodies directed to a specific epitope within the leucine zipper amino acid sequence 200–239 (p200) of the Ro52 protein correlate with prolongation of fetal atrioventricular (AV) time and heart block. This finding was further confirmed experimentally in that pups born to rats immunized with p200 peptide developed AV block. p200-specific autoantibodies cloned from patients bound cultured cardiomyocytes and severely affected Ca2+ oscillations, leading to accumulating levels and overload of intracellular Ca2+ levels with subsequent loss of contractility and ultimately apoptosis. These findings suggest that passive transfer of maternal p200 autoantibodies causes congenital heart block by dysregulating Ca2+ homeostasis and inducing death in affected cells

    Area of ischemia assessed by physicians and software packages from myocardial perfusion scintigrams.

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    The European Society of Cardiology recommends that patients with >10% area of ischemia should receive revascularization. We investigated inter-observer variability for the extent of ischemic defects reported by different physicians and by different software tools, and if inter-observer variability was reduced when the physicians were provided with a computerized suggestion of the defects
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