Methodology for integrated socio-economic assessment of offshore platforms : towards facilitation of the implementation of the marine strategy framework directive

In this paper a Methodology for Integrated Socio-Economic Assessment (MISEA) of the viability and sustainability of different designs of Multi-Use Offshore Platforms (MUOPs) is presented. MUOPs are designed for multi-use of ocean space for energy extraction (wind power production and wave energy), aquaculture and transport maritime services. The developed methodology allows identification, valuation and assessment of: the potential range of impacts of a number of feasible designs of MUOP investments, and the likely responses of those impacted by the investment project. This methodology provides decision-makers with a valuable decision tool to assess whether a MUOP project increases the overall social welfare and hence should be undertaken, under alternative specifications regarding its design, the discount rate and the stream of net benefits, if a Cost-Benefit Analysis (CBA) is to be followed or sensitivity analysis of selected criteria in a Multi-Criteria Decision Analysis (MCDA) framework. Such a methodology is also crucial for facilitating of the implementation of the Marine Strategy Framework Directive (MSFD adopted in June 2008) that aims to achieve good environmental status of the EU's marine waters by 2020 and to protect the resource base upon which marine-related economic and social activities depend. According to the MSFD each member state must draw up a program of cost-effective measures, while prior to any new measure an impact assessment which contains a detailed cost-benefit analysis of the proposed measures is required

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk

RELIABILITY-BASED DESIGN OPTIMIZATION USING OPTIMUM SAFETY FACTORS FOR LARGE-SCALE PROBLEMS

Introduction. Reliability-Based Design Optimization (RBDO) model reduces the structural weight in uncritical regions, does not only provide an improved design but also a higher level of confidence in the design.Materials and Methods. The classical RBDO approach can be carried out in two separate spaces: the physical space and the normalized space. Since very many repeated researches are needed in the above two spaces, the computational time for such an optimization is a big problem. An efficient method called Optimum Safety Factor (OSF) method is developed and successfully put to use in several engineering applications. Research Results. A numerical application on a large scale problem under  fatigue  loading  shows  the  efficiency of the developed RBDO method relative to the Deterministic Design Optimization (DDO). The efficiency of the OSF method is also extended to multiple failure modes to control several out-put parameters, such as structural volume and damage criterion.Discussion and Conclusions. The simplified implementation framework of the OSF strategy consists of a single optimization problem to evaluate the design point, and a direct evaluation of the optimum solution considering OSF formulations. It provides designers with efficient solutions that should be economic, satisfying a required reliability level with a reduced computing time

Efficient optimum safety factor approach for system reliability-based design optimization with application to composite yarns

Introduction. The integration of reliability and optimization concepts seeks to design structures that should be both economic and reliable. This model is called Reliability-Based Design Optimization (RBDO). In fact, the coupling between the mechanical modelling, the reliability analyses and the optimization methods leads to very high computational cost and weak convergence stability. Materials andMethods. Several methods have been developed to overcome these difficulties. The methods called Reliability Index Approach (RIA) and Performance Measure Approach (PMA) are two alternative methods. RIA describes the probabilistic constraint as a reliability index while PMA was proposed by converting the probability measure to a performance measure. An Optimum Safety Factor (OSF) method is proposed to compute safety factors satisfying a required reliability level without demanding additional computing cost for the reliability evaluation. The OSF equations are formulated considering RIA and PMA and extended to multiple failure case.Research Results. Several linear and nonlinear distribution laws are applied to composite yarns studies and then extended to multiple failure modes. It has been shown that the idea of the OSF method is to avoid the reliability constraint evaluation with a particular optimization process.Discussion and Conclusions. The simplified implementation framework of the OSF strategy consists of decoupling the optimization and the reliability analyses. It provides designers with efficient solutions that should be economic satisfying a required reliability level. It is demonstrated that the RBDO compared to OSF has several advantages: small number of optimization variables, good convergence stability, small computing time, satisfaction of the required reliability levels

Influence of wave effect on fiber stress limit under tensile tests of composite material

Introduction. The response of composite materials to the impact of a certain kind of load is difficult to predict, therefore, research in this area has often been neglected. The work objective was to study the influence of the wave effect on the tensile strength of polymer composites of a fibrous structure.Materials and Methods. In the tests, samples of multilayer materials of various thicknesses with continuous, long and short fibers that form a fabric, as well as a layered structure, were used. The number of layers corresponds to the resistance to the applied loads. Fibers of glass, carbon, kevlar, or their combinations were used. Isotropic materials – epoxide, polyester and vinyl ether – were used as binders.Research Results. The tensile test results of homogeneous samples and samples of fibrous structure are obtained. In this case, the values of fiber angle varied. The stability of their intercomparison test results is established. The dependence of the maximum tensile stresses σmax, MPa, (on the vertical axis) on the fiber angle θmax is obtained. These stresses for a fibreless material amounted to 250 MPa. Normal and tangential stresses acting perpendicular to the fibers, as well as shear stresses of the layered material, are calculated. As follows from the analysis of the dependences for the significant tensile stresses and from the study on refraction in the section of the sample damage, it was established that the shear stress τху was the cause of the fracture. Using an equation providing the compensation for the angle of inclination θ = 45, it was determined that the shear stress of the polyester is τху = 35 MPa. This was the stress that caused subsequently the destruction of the samples.Discussion and Conclusions. The tensile stresses of the composite material decrease with increasing the fiber angle in certain areas. The destruction of all fiber samples occurred when the shear stress reached a value approximately equal to the shear stress at which the destruction of samples made only from a binder material happened. When the specimen broke, the fracture mode had the form similar to the shear failure; besides, at the moment of fracture, the object having a rectangular shape, being deformed at an angle, took the form of a parallelogram

Evaluation of intensity modulated radiation therapy delivery system using a volumetric phantom on the basis of the task group 119 report of American association of physicists in medicine

The current work describes the implementation of the American Association of Physicists in Medicine (AAPM)'s Task Group 119 report on a volumetric phantom (Delta4, Scandidos, Uppsala, Sweden) following the stated dose goals, to evaluate the step-and-shoot intensity modulated radiation therapy (IMRT) system. Delta4 consists of diode detectors, lying on two crossed planes, measuring the delivered dose, and providing two-dimensional dosimetric information. Seven plans of different goals and complexity were performed, with individual structure sets. TG199 structure sets and plans were transferred and implemented on the Delta4 phantom taking into account its cylindrical geometry. All plans were delivered with a 6 MV linear accelerator equipped with multileaf collimator of 1 cm thickness. Plan results for each test met the recommended dose goals. The evaluation was performed in terms of dose deviation, distance to agreement, and gamma index passing rate. In all test cases, the gamma index passing rate was measured >90%. Delta4 phantom has proven to be fast, applicable, and reliable for the step-and-shoot IMRT commissioning following TG119's recommended tests. Although AAPM's TG119 report is referring to the implementation of test plans that do not correspond to patient plans, it could be used as an evaluation tool of various IMRT systems, considering the local treatment planning system and the delivery system

Effect of corrugated cardboard shape on the packing damping properties

The present work objective is searching for such forms of the cardboard corrugation which could effectively absorb the impact load on a cardboard sheet, both vertical and horizontal. The research subject is the depreciation efficiency of the cardboard package with a cell and an alternative (with MS-profile) structure by the action of shock across and along the honeycomb. Measurement and comparation of the deformation rate, as well as the shock absorption capacity of the sample cartons with the standard and alternative MS-corrugation are considered as the investigation tasks. The samples were under the impact force. Shock absorbing properties of the multilayer cardboard packaging in size of 127 × 127 mm were evaluated under the following conditions: drop height, 610 mm; impact speed, 3.5 m/s; falling weight, 12.5 kg; pressure load, 340 kg. In this case, pressing force, impact energy, deformation value is recorded. As a result of the experiments, it was found that a three- and five-layer sample with MS-profile has better shock absorbing properties (as compared to a standard cellular cardboard of the same thickness). The application of seven- and nine-layer cardboard with MS-profile is inappropriate due to a minor advantage over a three- and five-layer sample