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This research proposes a novel nature-based design of a new concrete armour unit for the cover layer of a rubble-mound breakwater. Armour units are versatile with respect to shape, orientation, surface condition details, and porosity. Therefore, a detailed analysis is required to investigate the exact state of their hydraulic interactions and structural responses. In this regard, the performance results of several traditional armour units, including the Antifer cube, Tetrapod, X-block and natural stone, are considered for the first step of this study. Then, the related observed results are compared with those obtained for a newly designed (artificial coral) armour unit. The research methodology utilizes the common wave flume test procedure. Furthermore, several verified numerical models in OpenFOAM code are used to gain the extra required data. The proposed armour is configured to provide an effective shore protection as an environmental-friendly coastal structure. Thus it is designed with a main trunk including deep grooves to imitate the typical geometry of a coral type configuration, so as to attain desirable performance. The observed results and an analytic hierarchy process (AHP) concept are used to compare the hydraulic performance of the studied traditional and newly proposed (artificial coral) armour units. The results indicate that the artificial coral armour unit demonstrates acceptable performance. The widely used traditional armour units might be replaced by newer designs for better wave energy dissipation, and more importantly, for fewer adverse effects on the marine environment. [ABSTRACT FROM AUTHOR]

A probabilistic approach is used to compute the probabilistic responses of considered fluid-conveying pipes by combining the Galerkin method and Monte Carlo simulation. Analysing the fluid-conveying pipes is often performed based on the deterministic approaches, but the effect of uncertainty needs to be investigated. The natural frequencies can be represented using probabilistic methods by considering the inherent uncertainty in estimating values. The uncertainty was considered as a random variable. The effects of coefficient of variation (COV) associated with the fluid velocity on the probabilistic characteristics are evaluated. The probability distribution functions of natural frequencies are presented. The measured values were validated by comparing with results of the stochastic finite element method. The results imply that the peak points for the diagrams of the standard deviations of the velocity values gained by the Monte Carlo simulation versus the mean velocities of the related values are equal to the critical fluid velocity. [ABSTRACT FROM AUTHOR]

Nowadays, admixtures are used with the aim to provide strength and durability to concrete with less water use. New and low-cost admixtures gained a large amount of consideration to mitigate the problems associated with concrete's durability and service life without upsetting its strength properties. The current work investigates the effect of three types of acetates on the workability, density, and compressive strength of concrete, which is used in structures of the Iraqi ports that suffer from corrosion damages and deterioration owing to the aggressive marine environments. Potassium acetate (KA), calcium acetate (CaA), and ethyl acetate (EA) are incorporated with different doses (1.38–5.6 wt.% of cement) in concrete mixtures using different water/cement ratios (0.48–0.54) based on an espoused central composite experimental design. The experimental results confirmed that the average workability increased with increasing the acetate dose, particularly with CaA. The density and compressive strength of 28 days of water-cured mixtures increased with increasing acetate dose following the order: Ca > K > Ethyl acetate and decreased with increasing w/c ratio. The high rise in compressive strength and workability linked to control mixtures was 30.8% and 77.3% as well as 15.7% and 64.3% for the mixtures incorporated with 5.6 wt.% CaA and KA, respectively. While it was 14.2% and 58.3% for the mixtures incorporated with 3.5 wt.% EA. RSM was employed to optimize and model the design and hardened properties of concrete mixtures. ANOVA results predicted the same trend, which was obtained from the experimental results. The mathematical models were valued with high-regression coefficients. The highest compressive strength of 42.68 MPa has been achieved for a concrete mixture of 0.48 w/c ratio by the incorporation of 5.1 wt.% CaA through a model with R2 96.97%. The relatively low-cost acetate admixtures, particularly CaA, seemed promising for the fabrication of concrete with outstanding properties. [ABSTRACT FROM AUTHOR]

Reducing structural vibrations in offshore marine structures is of great importance due to fatigue-based failures. Employing a damping system within the structure can be defined as the best choice to reduce vibrations. In this paper, the performance of a magneto-rheological tuned liquid column damper (MR-TLCD) system on a three-dimensional fixed offshore structure is studied. The efficiency of the system is investigated considering different wave and earthquake forces in addition to utilizing a traditional tuned liquid column damper (TLCD). Magneto-rheological (MR) fluids yield-stress, which is the most important factor in increment of the damper capability, is studied within different values under wave and earthquake forces. Due to the frequency dependency of liquid column dampers, the damping system results are compared using three mass and frequency ratios. Based on the results, the MR-TLCD system shows great promise in mitigating structural vibrations. The results also indicate the importance of yield stress parameter investigation because of its significant effects on the structural response of the system. [ABSTRACT FROM AUTHOR]

Different sensing methods provide valuable information for comprehensive monitoring strategies, which are crucial for the ecological management of lakes and watersheds. Subsequently, the resulting spatio-temporal information can be considered the fundamental knowledge for the water resources management of watersheds. Lake Urmia is deemed one of the most important aquatic habitats in Iran. It has been experiencing significant changes during recent years due to climate change, anthropogenic activities, and a lack of coherent management approaches. Hence, awareness of the hydro-ecological factors during the last few decades is critical for identifying the problems. In this research, the impacts of changes in key parameters such as precipitation, evapotranspiration, water surface temperatures, suspended sediment concentration, saline features, and vegetation are explored using satellite imagery. The primary purpose of this study is to evaluate the Lake Urmia crisis concerning human-involved and climate factors such as the agriculture sector and construction of the causeway. In this regard, a limbic-based Emotional Artificial Neural Network (EANN) is developed as a non-linear universal mapping and implemented for the first time to demonstrate the interactions between the considered hydro-ecological factors and the sensitivity of the two indicators the lake health. Providing a comprehensive spatio-temporal analysis is another objective of this study to detect the onset of deterioration in the parameters. The values of the efficiency criteria were measured to evaluate the sensitivity of the EANN models to the related inputs. The results of the model in scenario 4 with evapotranspiration, precipitation, runoff and vegetation as input variables led to higher performance with the best efficiency criteria, including DC = 0.868 and RMSE = 0.096. The quantitative results confirm that the combination of both climate and anthropogenic factors, including the agricultural sector's overdraft, leads to the most efficient EANN model and, consequently, is considered the leading cause of the crisis. [ABSTRACT FROM AUTHOR]

In the present study, a new wetland health assessment approach based on the fuzzy inference system (FIS) was developed and proposed for the first time to improve a traditional wetland classification and assessment index. One primary purpose of the study is to modify the indicators of the traditional assessment approach to suit the regional environmental conditions of the selected areas. As two of the twenty-five Iranian wetlands with international importance, Kanibarazan and Choghakhor wetlands were selected as the study areas due to their significant roles in protecting the biodiversity of their regions. The wetlands are supported by the international Ramsar Convention on Wetlands to mandate and encourage the local authorities towards their conservation and sustainable exploitation. In this regard, the Iranian Department of Environment, in cooperation with the Global Environment Facility (GEF) and the United Nations Development Programme (UNDP), selected these wetlands to demonstrate new approaches of managing the wetland areas protected by the Conservation of Iranian Wetlands Project (CIWP). A real-time wetland monitoring station with hydrological instruments, including water level, air temperature, air humidity, and water quality multi-parameter sensors recording water temperature, pH, electrical conductivity, and dissolved oxygen (DO), was implanted at the deepest part of both wetlands. The manual sampling of water quality parameters was also carried out periodically during specific intervals. The relative importance of the wetland health indicators involved in the FIS was determined via the analytic hierarchy process (AHP), utilizing the knowledge of local experts, including academic staff, environmental specialists, and natives, to localize the traditional assessment approach. In turn, the health level categories of both wetlands were assessed using the traditional and proposed wetland health assessment approaches. The efficiency of the proposed method was evaluated with the selected case studies, and it proved to be a more flexible and appropriate approach for wetland health assessment. Furthermore, the observed differences between the health level of the first case study pointed to the efficiency of the AHP-FIS method in improving the traditional index. Besides, feedforward neural network (FFNN) and support vector regression (SVR) artificial intelligence (AI) methods were used to model DO as one of the most critical water quality parameters in maintaining the biological integrity of wetland ecosystems. The obtained results indicated that FFNN performed slightly better than SVR in predicting DO of both wetlands. Consequently, the results of DO modeling were used to investigate the possibility of employing AI models in wetland health assessment in case of unavailability or failures of DO sensors, which was considered practical considering the suitable performance of AI models and the obtained wetland health level results based on the predicted DO. Highlights: 1. A wetland health assessment approach based on fuzzy logic was developed. 2. Two freshwater wetlands were selected as real case study areas. 3. The fuzzy inference system and analytic hierarchy process were used to improve the process. 4. The proposed approach showed more flexibility and efficiency. 5. Two AI methods were used to model DO and investigate their applicability in health assessment. [ABSTRACT FROM AUTHOR]

Face stability is a critical issue in the stability analysis of tunnels, especially in soft soils and crushed rock masses. In this paper, considering two three-dimensional collapse mechanisms, upper-bound solutions are presented for determining the face pressure of deep and shallow tunnels excavated in rock masses. The Hoek–Brown failure criterion was considered for the rock mass surrounding the tunnel. The proposed upper-bound formulations were compared with three-dimensional finite-element simulations and also with centrifuge test results available in the literature. The obtained results showed that the face pressure decreases with increasing σci, mi, and geological strength index. Besides, increasing the tunnel diameter and the rock mass density led to an increase in the face pressure, where for larger tunnels, the effect of the density became more pronounced. Finally, some charts were presented to specify the range of applicability of the concepts of deep and shallow tunnels. The results obtained from these charts demonstrated that the reduction in the Hoek–Brown parameters of the rock mass results in spreading the collapse mechanism from the tunnel face to the ground surface. [ABSTRACT FROM AUTHOR]

Conventional design of pier structures is based on the assumption of fully rigid joints. In practice, the real connections are semi-rigid that cause changes in dynamic characteristics. In this study, quality of the joints is investigated by considering changes in natural frequencies. For this purpose, numerical and experimental modal analyses are carried out on related physical model of a pier type structure. When numerical results are evaluated, natural frequencies generally do not match the expected experimental results. Uncertainties in different aspects of engineering problems are always a challenge for researchers. The numerical models which are constructed on the basis of highly idealized scheme may not be able to represent all of the physical aspects of the physical one. For this study, determination of percentage of semi-rigid joints is considered as an optimization problem based on the numerical and experimental frequencies. Probabilistic sensitivity analysis is also used to determine the search space. A new technique of optimization problem is solved by a combination of smart particle swarm optimization (PSO) and genetic algorithms, and a complicated and efficient system for model updating process is introduced. It is observed that the hybrid PSO-Genetic algorithm is applicable and appropriate in model updating process. It performs better than PSO algorithm, considering the good agreement between theoretical frequencies and experimental ones, before and after model updating. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the diagnostic accuracy of split-bolus single-scan computed tomography angiography (CTA) protocol for evaluation of acute mesenteric ischemia and alternate diagnoses.Materials and Methods: In this IRB-approved, HIPAA-compliant retrospective study, consecutive patients from 21 October 2016 to 6 May 2018 evaluated for mesenteric ischemia with split-bolus CTA (a single scan in concurrent arterial and portal venous phase) in a single tertiary academic institution were included. Intravenous contrast was administered on weight-based basis. Quantitative and qualitative assessments of superior mesenteric artery (SMA) and superior mesenteric vein (SMV) attenuation and patency were performed by two independent reviewers. CT imaging findings were correlated with clinical reference outcomes.Results: One hundred fifty-four patients (age 66.3 ± 14.1 years, BMI 27.3 ± 6, 86 (56%) female) were included. CTA studies were performed with a volumetric CT dose index of 15.9 ± 5.5 mSv and dose length product of 1042.9 ± 389.4 mGy cm. Average intravenous contrast volume administered was 164.3 ± 12.1 cc. SMA attenuation was 263.6 ± 92.4HU, SMV was 190 ± 50.2HU. Qualitative assessment of SMA and SMV showed good opacification in all patients. 17/154 (11%) patients were diagnosed on CT with mesenteric ischemia; in 6/154 (4%), CTA studies were indeterminate; in 131/154 (85%), CTA confidently ruled out mesenteric ischemia. Alternate diagnoses were made in 38/154 (25%) patients. Using composite clinical outcomes as a reference standard, sensitivity of split-bolus CTA protocol for diagnosis of mesenteric ischemia is 100% (95% CI 79-100%), and specificity is 99% (95% CI 96-100%).Conclusions: Split-bolus CTA has high sensitivity and specificity for diagnosis of acute mesenteric ischemia.Key Points: • Split-bolus CTA protocol for mesenteric ischemia has great diagnostic accuracy with lower radiation exposure and fewer images to interpret compared with standard multiphasic CTA. [ABSTRACT FROM AUTHOR]

Offshore jacket platforms have been widely developed and their damage detection is of great importance to ensure their safe operation. Structural health monitoring method (SHM) has been used to decline the effect of the damages caused by marine environmental conditions. Global SHM methods are considered as efficient methods which include both economic and safety issues, and use modal characters of the structure. Major parts of offshore structures which are not available for diagnosing change the monitoring process to a big challenge. Different procedures have been used for diagnosing process, where simulating the structure as a finite element (FE) model is the most common one. Comparison between defected structures FE model and the intact model of the structure is the fundamental concept of SHM diagnostic. Mathematical models are used to develop limited measured data for health monitoring. An important step in SHM process includes FE model updating which is applicable using similar algorithms with diagnosing process. Some algorithms, such as neural network, have been used to detect the damage patterns, where their developing complication is their most important challenge. In this study, a new Fuzzy–Krill Herd algorithm is used to perform structural health monitoring process in a fixed jacket platform and compared with common fuzzy–genetic method. For this purpose, an experimental fixed platform model (SPD9 located in Persian Gulf) is prepared to obtain modal parameters using vibration behavior. Structural FE model is built and numerical model updating is performed on the results of the physical model. Moreover, the effects of uncertainty in damages and health monitoring in experimental and numerical models are considered for detecting damages and monitoring the structure. Using a combination of smart algorithms and fuzzy logic, a complicated and efficient system for structural health monitoring process is introduced. The suggested Fuzzy–Krill Herd method is shown to be applicable and appropriate in SHM process and also for handling noisy data. [ABSTRACT FROM AUTHOR]

Bullet embolization to the right heart through the vasculature is seen infrequently in cases presenting with penetrating trauma. Patients with unstable hemodynamic status are managed operatively. For a patient with stable hemodynamic parameters, diagnostic evaluation such as computed tomography angiogram, echocardiogram, or angiography could be performed to select the best treatment option. Endovascular treatment is employed infrequently in these cases but can be a viable option for select patients. We present a case of a bullet embolus to the right ventricle treated successfully with endovascular approach and discuss the technical aspects of this approach. [ABSTRACT FROM AUTHOR]

Among numerous offshore structures used in oil extraction, jacket platforms are still the most favorable ones in shallow waters. In such structures, log piles are used to pin the substructure of the platform to the seabed. The pile's geometrical and geotechnical properties are considered as the main parameters in designing these structures. In this study, ANSYS was used as the FE modeling software to study the geometrical and geotechnical properties of the offshore piles and their effects on supporting jacket platforms. For this purpose, the FE analysis has been done to provide the preliminary data for the fuzzy-logic post-process. The resulting data were implemented to create Fuzzy Inference System (FIS) classifications. The resultant data of the sensitivity analysis suggested that the orientation degree is the main factor in the pile's geometrical behavior because piles which had the optimal operational degree of about 5° are more sustained. Finally, the results showed that the related fuzzified data supported the FE model and provided an insight for extended offshore pile designs. [ABSTRACT FROM AUTHOR]

A new fault classification/diagnosis method based on artificial immune system (AIS) algorithms for the structural systems is proposed. In order to improve the accuracy of the proposed method, i.e., higher success rate, Gaussian and non-Gaussian noise generating models are applied to simulate environmental noise. The identification of noise model, known as training process, is based on the estimation of the noise model parameters by genetic algorithms (GA) utilizing real experimental features. The proposed fault classification/diagnosis algorithm is applied to the noise contaminated features. Then, the results are compared to that obtained without noise modeling. The performance of the proposed method is examined using three laboratory case studies in two healthy and damaged conditions. Finally three different types of noise models are studied and it is shown experimentally that the proposed algorithm with non-Gaussian noise modeling leads to more accurate clustering of memory cells as the major part of the fault classification procedure. [ABSTRACT FROM AUTHOR]

Groins are employed to prevent nearshore areas from erosion and to control the direction of flow. However, the groin structure and its associated flow characteristics are the main causes of local erosion. In this study, we investigate the flow patterns around refractive and right-angle groins. In particular, we analytically compare the flow characteristics around a refractive groin and study the degree of accuracy that can be achieved by using a right-angle groin of various projected lengths. To compare the flow characteristics, we replaced the right-angle groin with an approximation of a refractive groin. This replacement had the least effect on the maximum velocity of flow in the channel. Moreover, we investigated the distribution of the density variables of temperature and salinity, and their effects on the flow characteristics around the right-angle groin. A comparison of the flow analysis results in baroclinic and barotropic conditions reveals that the flow characteristic values are very similar for both the refractive and right-angle groins. The geometry of the groin, i.e., right-angle or refractive, has little effect on the maximum speed to relative average speed. Apart from the angular separation, the arm length of the groin in downstream refractive groins has less effect on other flow characteristics than do upstream refractive groins. We also correlated a number of non-dimensional variables with respect to various flow characteristics and groin geometry. These comparisons indicate that the correlation between the thalweg height and width of the channel and groin arm's length to projection length have been approximated using linear and nonlinear formulas regardless of inner velocity in the subcritical flow. [ABSTRACT FROM AUTHOR]

Background. The purpose of the study was to evaluate the correlation between the maximum standardized uptake value (SUVmax), size of primary lung lesion, disease-free survival (DFS) and overall survival (OS) in patients with stage I and II non-small cell lung cancer (NSCLC) in 2 years follow-up. Patients and methods. Forty-nine patients with stage I-II NSCLC were included in this study. Pre-surgical 2-deoxy- 2-[18F]fluoro-D-glucose positron-emission tomography (18F-FDG PET/CT) study was performed for all patients. The relationship between SUVmax, tumour size and clinical outcome was measured. The cut-off value for SUVmax and tumour size with the best prognostic significance, probability of DFS and the correlation between SUVmax and the response to therapy were calculated. Results. There was a statistically significant correlation between SUVmax and DFS (p = 0.029). The optimal cut-offs were 9.00 for SUVmax (p = 0.0013) and 30mm for tumour size (p = 0.0028). Patients with SUVmax > 9 and primary lesion size > 30 mm had an expected 2years-DFS of 37.5%, while this rose to 90% if the tumour was <30 mm and/or SUVmax was <9. Conclusions. In stage I-II, SUVmax and tumour size might be helpful to identify the subgroup of patients with high chance for recurrence. [ABSTRACT FROM AUTHOR]

Pendred syndrome, defined as the constellation of goiter, sensori-neural hearing loss, and positive perchlorate discharge test, is the most frequent cause of congenital deafness. Newly introduced diagnostic approaches to the disease are rather expensive and complicated, therefore we evaluated the value of MRI as the sole, or adjunctive diagnostic approach, and compared it with the traditional ones. Presuming the classic triad as the gold standard, we compared MRI findings in six such defined patients with six cases having goiter, hearing loss, and normal perchlorate discharge test. Our results indicated that MRI was 83.6% sensitive and 66.7% specific in patients fulfilling all three criteria (complete), while in the 'partial' group the sensitivity and specificity were 66.7% and 100% respectively. In conclusion, MRI, although impressive as an adjunctive diagnostic tool, may not replace the holistic approach, and the latter may be more convenient, cheaper, and still more accurate. However in 'partial' cases with equivocal findings, and in relatives of the patients, MRI may be a valuable diagnostic adjunct. [ABSTRACT FROM AUTHOR]

Objective: This study aimed at comparing the urinary protein levels in calcium stone formers with those of healthy individuals. Patients and Methods: From January 2002 until June 2004, 100 calcium stone formers (mean age 38.6 ± 10.3 years), who had at least two episodes of calcium stone formation, were compared with 100 healthy individuals (mean age 33.8 ± 9.7 years). Their 24-hour urinary protein levels, using SDS-PAGE, were measured. Results: The mean 24-hour urinary Tamm-Horsfall protein (THP) levels were 3.3 ± 0.8 mg in the case group and 4.6 ± 1.9 mg in the controls, and the difference was not statistically significant (p = 0.53). However, the THP levels in individuals with and without bacteriuria were significantly different (15.8 ± 3.3 mg vs. 2.6 ± 1.0 mg, p = 0.0001). The mean 24-hour urinary albumin concentrations were 163.31 ± 15.1 mg in the case group and 74.26 ± 4.6 mg in the controls. The mean 24-hour urinary transferrin levels were 8.09 ± 2.7 mg in the case group and 0.40 ± 0.3 mg in the controls. The differences were statistically significant for both albumin and transferrin (p < 0.0001 and p = 0.0063, respectively). There were no significant differences in any other mean urinary protein concentrations between cases and controls. Conclusions: The THP level in the urine of stone formers is not quantitatively different from that of healthy individuals, but it increases in association with bacteriuria. Albumin and transferrin may play a presumptive role in stone formation. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Osteoporosis is a major problem and is a hidden epidemic disease in the world. Early diagnosis by measurement of Bone Mineral Density (BMD) and treatment can prevent and reduce disease complications, especially fractures. As there is no comprehensive study in Iran, this study designed to assess BMD discrepancy in 20-69 yr Tehran population as well as prevalence of osteoporosis and osteopenia. Methods: 553 people (34% men, 66%women) from 50 Blocks in Tehran randomly selected. The assessment of BMD in spine and femur region performed through DXA method. All subjects clinically examined and their BMIs determined. Results: The average spinal BMD score in men were more than in women. The peak bone mass of spine bone both in men and women occurred during 20-29 yr and reduction began from the age of 40. At the age of 60 to 69, loose of bone density was 19.6% in lumbar spine and 18.5% in femur of women and also 7.9% in lumbar spine and 14.6% in femur of men. Prevalence of osteoporosis in this age group in lumbar spine and femur was 32.4% and 5.9% in women and 9.4% and 3.1% in men respectively. Conclusion: In all age groups, peak bone mass was lower than European or American population, whereas the rate of bone loss was as much as the some population and actually this process justifies the prevalence of osteoporosis and osteopenia in Tehran population. [ABSTRACT FROM AUTHOR]