156 research outputs found
Advanced framework for degradation modeling of operating structures
The safe operation of steel structures, such as bridges, is of paramount importance to mitigate potential issues. Consequently, the continuous and thorough monitoring of their operational conditions is imperative to uphold their safety and reliability. However, the inexorable process of corrosion, catalyzed by environmental conditions, leads to the inevitable deterioration of structural integrity over time. This research endeavors to predict the extent of corrosion in the primary cables of bridges through the application of advanced methodologies based on machine learning techniques. The execution of the proposed model necessitates the utilization of an extensive database encompassing diverse characteristics pertaining to the environmental properties of the surrounding region. The performance of the proposed models is rigorously assessed using a comprehensive suite of statistical and graphical metrics. The findings of this investigation underscore the effectiveness of the recommended solutions, surpassing previously established methodologies in addressing this pressing issue. The demonstrated success of the proposed model augurs favorably for its potential utility in furthering research into the dependability assessment of suspension bridge main cables.</p
Antenatal diagnosis of extralobar pulmonar sequestration
Extralobar pulmonary sequestrations (ELS) are masses of non-functioning lung tissue that are supplied by an anomalous systemic artery and do not have a bronchial connection to the native tracheobronchial tree. On prenatal ultrasonography, an ELS appears as a well-defined echodense, homogeneous mass. Detection by color flow Doppler ultrasonography of a systemic artery from the aorta to the fetal lung lesion is a pathognomonic feature of fetal ELS. MR imaging may help in the diagnosis of pulmonary sequestration by demonstrating a solid, well-defined mass, and the feeding artery. In this case report, we describe the sonographic and MR diagnosis of an ELS in a fetus at 22 weeks gestation with a review of the available literature.Key words: Extralobar pulmonary sequestration, antenatal diagnosis, ultrasonography, MR
Comparative study on the efficiency of simulation and meta-model-based Monte Carlo techniques for accurate reliability analysis of corroded pipelines
Estimation of the failure probability for corroded oil and gas pipelines using the appropriate reliability analysis method is a task with high importance. The accurate prediction of failure probability can contribute to the better integrity management of corroded pipelines. In this paper, the reliability analysis of corroded pipelines is investigated using different simulation and meta-model methods. This includes five simulation approaches, i.e., Monte Carlo Simulation (MCS), Directional Simulation (DS), Line Sampling (LS), Subset Simulation (SS), and Importance Sampling (IS), and two meta-models based on MCS as Kriging-MCS and Artificial Neural Network based on MCS (ANN-MCS). To implement the proposed approaches, three limit state functions (LSFs) using probabilistic burst pressure models are established. These LSFs are designed for describing the collapse failure mode for pipelines constructed of low, mid, and high strength steels and are subjected to corrosion degradation. Illustrative examples that comprise three candidate pipelines made of X52, X65, and X100 steel grade are employed. The performance and efficiency of the proposed techniques for the estimation of the failure probability are compared from different aspects, which can be a useful implementation to indicate the complexity of handling the uncertainties provided by corroded pipelines
Random forest-based algorithms for accurate evaluation of ultimate bending capacity of steel tubes
Despite the existence of methods for estimating the behavior of steel circular tubes subjected to pure bending, analytical models are still restricted due to the problem's complexity and significant nonlinearity. Using the random forest (RF) as the basic model, novel intelligent models are constructed to estimate the ultimate pure bending capacity of circular steel tubes in this study. The RF model's parameters are optimized using three nature inspired optimization algorithms, namely, the particle swarm optimization (PSO), ant colony optimization (ACO) and whale optimization algorithm (WOA). In the experimental part, a database of 104 tests that comprise 49 and 55 pure bending tests conducted on fabricated and cold-formed steel circular tubes, respectively, are evaluated and utilized to investigate the applicability of the hybrid RF-models. A single RF model is also built for comparative reasons in order to estimate the ultimate pending capacity. Various statistical and graphical measures are used to evaluate the performance of the developed models. The results show that the proposed RF-based nature-inspired algorithms can outperform the original RF predictive model. When the hybrid-RF models were assessed, it was discovered that the RF-WOA performed best. In addition, the influence of each parameter on the prediction findings based on the best RF-model is investigated via sensitivity analysis. Taking into account the overall findings, the hybrid RF-models may be used as powerful tools to predict the ultimate bending capacity of circular steel tubes and may be viable to aid technicians in making proper judgments.Scopu
Genomic DNA extraction from the medicinal plant Crocus sativus : Optimization of Standard Methods
High-quality genomic DNA is essential for genomic and molecular investigations such as next-generation sequencing. However, DNA extraction from medicinal plants like Crocus sativus can be challenging due to their high secondary metabolite content, which can interact with nucleic acids and affect the quality and yield of extraction. This study aimed to optimize the quality and yield of DNA using the cetyltrimethylammonium bromide (CTAB) extraction method from the leaves, stigma, and saffron corm. This new method is easy to use and can be performed using standard equipment and inexpensive reagents. The modifications made to the CTAB lysis buffer in this study, with the addition of SDS, resulted in a yield of 4233 ng/µl of DNA per sample of saffron corm (100 mg). This protocol is efficient and cost-effective for DNA extraction for studies with large samples and limited resources. This method is expected to be widely used for large-scale plant extraction and has a broad application in PCR-based sequencing studies
Clinicopathological and therapeutic features of metaplastic carcinoma of the breast: a study of 15 cases
Background: Metaplastic carcinoma of the breast is a rare entity containing a mixture of malignant epithelial and mesenchymal elements. The World Health Organization only recognized it as a distinct pathological entity since 2000. The aim of this study is to better characterize this rare disease.Methods: We reviewed retrospectively 15 cases of metaplastic carcinoma of the breast treated in our institute between 1994 and 2015. We analyzed clinical, histological, therapeutic and evolutive data.Results: All patients were females ranging from 29 to 75 years old (median, 50). Tumor size ranged from 20 to 150 mm (median, 72 mm). The Treatment consisted of radical mastectomy in 14 cases, often combined with post-operative radiation and/or chemotherapy. There were 8 cases of carcinosarcoma, 4 cases of spindle cell carcinoma and 3 cases of squamous cell carcinoma. Follow-up data were available on 12 patients. The median follow-up was 47 months (range, 10 to 146 months). Definitive nodal metastases were identified in 6 cases. One patient developed a local recurrence. Extranodal metastases occurred in 3 patients. Three patients died at median interval of 20 months (range, 13-30). Eight patients were alive with no evidence of recurrent or metastatic disease (median, 47 months) and one patient was alive with metastatic disease.Conclusions: Based on this series, metaplastic breast carcinoma is characterized by a large tumor size at presentation, a low frequency of nodal metastases and a high proportion of triple negativity. Our series is consistent with the literature
Rigorous Connectionist Models to Predict Carbon Dioxide Solubility in Various Ionic Liquids
Estimating the solubility of carbon dioxide in ionic liquids, using reliable models, is of paramount importance from both environmental and economic points of view. In this regard, the current research aims at evaluating the performance of two data-driven techniques, namely multilayer perceptron (MLP) and gene expression programming (GEP), for predicting the solubility of carbon dioxide (CO2) in ionic liquids (ILs) as the function of pressure, temperature, and four thermodynamical parameters of the ionic liquid. To develop the above techniques, 744 experimental data points derived from the literature including 13 ILs were used (80% of the points for training and 20% for validation). Two backpropagation-based methods, namely Levenberg–Marquardt (LM) and Bayesian Regularization (BR), were applied to optimize the MLP algorithm. Various statistical and graphical assessments were applied to check the credibility of the developed techniques. The results were then compared with those calculated using Peng–Robinson (PR) or Soave–Redlich–Kwong (SRK) equations of state (EoS). The highest coefficient of determination (R2 = 0.9965) and the lowest root mean square error (RMSE = 0.0116) were recorded for the MLP-LMA model on the full dataset (with a negligible difference to the MLP-BR model). The comparison of results from this model with the vastly applied thermodynamic equation of state models revealed slightly better performance, but the EoS approaches also performed well with R2 from 0.984 up to 0.996. Lastly, the newly established correlation based on the GEP model exhibited very satisfactory results with overall values of R2 = 0.9896 and RMSE = 0.0201.publishedVersio
The Spiny Lobster, Palinurus mauritanicus (Gruvel, 1911) from Algerian West Coasts: A Species to Protect.
The study of the biometric characteristics of the pink lobster, Palinurus mauritanicus allowed us to define some parameters related to reproduction and growth of a noble little-known species in the Mediterranean, which is not protected in Algeria, and tends to be scarce. To avoid future a pronounced decline in the fishable stock and allow a rational balance of specimens attending island fishing areas; our recommendations are based on observations made ??during sampling process that are resumed as follows: prohibit throughout the year capture of berried females, and returned them to water in case of accidental trawl capture, closing the lobster fishing during periods of reproduction and egg maturation (July, August an
- …