Experimental and Numerical Investigation of Local Scouring around Bridge Piers in Different Geometric Shapes at a 90° Convergent meander

The presence of several convergent meanders is a basic characteristic of natural flowing rivers. It is important to construct bridge piers in different geometric shapes at convergent meanders. The formation of secondary flows at meanders and their enhancement by the convergence effect can bring complexities and irregularity in the erosion pattern around bridge piers. The present study experimentally and numerically investigates the effects of the geometric shapes of bridge piers on local scour around piers at a 90° convergent meander. Tests were carried out within a channel with a 90° convergent meander and a centerline radius of 170 cm. Cylindrical piers with the diameters of 40 and 60 mm and cubic piers with the sizes of 40*40 and 60*60 mm were placed at the center of the meander, investigating scour in clear-water conditions. Also, a three-dimensional SSIIM-2 model was employed to simulate the problem and compare the results to the experimental ones. The results indicated that the shapes and sizes of the piers affected the scour depth, and the maximum scour depth was estimated to be smaller around the cylindrical piers than around the cubic piers in all the tests. Moreover, convergence-induced contraction along with the placement of the piers at the meander enhanced scour around the piers. The numerical SSIIM-2 results were found to be in a good agreement with the experimental results

Experimental and numerical investigation the effect of pier position on local scouring around bridge pier at a 90° convergent bend

Natural rivers have several bends along the path that are not generally uniform and some are convergent. Installing the bridge piers in river convergent bends may result in complicated flow and erosion patterns around the bridge piers. Most of previous studies on the flow and the scour pattern around piers were carried out in straight channels and fixed-width bends. Studying the local scouring around pier located at a converging bend, experimentally and numerically, has brought novelty to this paper. In this research, a physical hydraulic model with a 90° convergent bend and central radius of 170 cm was built. A cylindrical pier with a diameter of 60 mm was installed in positions of 0, 30, 45, 60, and 75 degrees and local scour were studied under clear-water conditions. The SSIIM-2 numerical model was also used to simulate the scour pattern and the results were compared with experimental results. The results showed that, increasing the convergence and changing the pier position in a bend leads to an increment in the continuity between the flow lines and secondary currents, respectively, so that the maximum depth and volume of the scour hole occurred in the second half of the bend at an angle of 75 degrees. The comparison between experimental and numerical data shows that SSIIM-2 model can efficiently simulate the scour pattern in a 90° convergent bend. Furthermore, in all cases by increasing the Froude number, maximum depth and volume of the scour hole were increased

In Vitro Evaluation of the Composition of Rectangular Panels Connected to the Beach and Horizontal Blade in Controlling Erosion of Convergent 90-Degree Arch

On the river arch, the formation of secondary flow causes erosion in the outer bank and sedimentation in the inner bank. Sediment accumulation in downstream of arches causes decrease in the river width and therefore arces are mainly seen as convergent in nature. Controlling erosion in the outer bank of arches is done in various ways including the use of spur dike structures. In the rigid spur dike, the flow hitting to the structure body creates a downstream flow and causes aggravated scour around the spur dike; therefore, in order to solve and control this problem it is possible to install horizontal panels on spur dikes. In the this study, in ordr to investigate the effect of horizontal panels installed on the thalweg bed, by making a 90 degree convergent arched channel and installating 4 rectangular spur dike in the positions of 30, 45, 60 and 75 degrees in a way in which the panels occupied 15 percent of the channel width and installing horizontal panels with a length of 10 cm and a width appropriate to the spur dike in three positions of 3 cm above the bed, on the bed and 3 cm below the bed, and by considering the sandy bed thickness of 15 cm and the average diameter of sediment equal to 1.15 mm, a total of 15 tests were carried out in different conditions with three discharges. The results of this study showed that the spur dike are generally successful on the movement of the thalweg and installing horizontal panels causes aggravated thalweg, so that in installation conditions at different altitudes of scour depending on the flow conditions and Froude number the effectiveness of spur dike is different

Onset and duration of 2% lidocaine as inferior alveolar nerve block versus buccal/lingual infiltration of 4% articaine in mandibular second molars: Clinical trial study

BACKGROUND AND AIM: The effectiveness of buccal or lingual (B/L) infiltration of 4% articaine as supplemental injection for pulp anesthesia of mandibular teeth was confirmed in previous studies. However, this study was aimed to compare the effectiveness of 2% lidocaine as inferior alveolar nerve block (IANB) versus B/L infiltration of 4% articaine for pulp anesthesia, as primary injection in mandibular second molars. METHODS: Thirty adult volunteers ranging from 18 to 40 years old with no systemic disease or medicine intake were included in this split-mouth, double-blind, randomized clinical trial study. Each mandibular side of included subjects was allocated randomly to control group (IANB using 2% lidocaine and 1/80000 epinephrine using direct technique) and B/L infiltration group using 4% articaine (Septanest; Septodont, Saint-Maur-des-Fosses, France). After obtaining base line sensitivity, electric pulp testing (EPT) was done at 5, 8, 11, 15, 20, 25, 30, 45, 60, 75, and 90 minutes post injections. The data were analyzed using chi-square test. RESULTS: The success rate of anesthesia for IANB group was 83.3% (25 of 30 subjects) and 30% (9 of 30 subjects) for B/L infiltration group, and the difference between the groups was statistically significant (P = 0.0005). The mean onset time of pulp anesthesia for IANB group was 22.6 ± 30.9 minutes and 65.5 ± 38.0 for B/L infiltration group, and the difference between the groups was statistically significant (P = 0.0001). The mean duration time of pulp anesthesia for IANB group was 53.0 ± 27.4 minutes and 10.6 ± 17.2 for B/L infiltration group, and the difference between the groups was statistically significant (P = 0.0001). CONCLUSION: The results indicated that IANB using 2% lidocaine was more successful than B/L infiltration of 4% articaine in onset and duration of pulp anesthesia of mandibular second molars as primary injections. KEYWORDS: Articaine; Lidocaine; Local Anesthesia; Molar; Inferior Alveolar Nerve; Volunteer

Investigating the Effects of the Block Geometries and Sidewall Divergences on the Local Scour Downstream of Baffled Chute Spillways

Due to the lack of any specific study about the sidewalls and other blocks’ changes in the case of hydraulic and scour downstream, the present study was conducted to investigate this issue. For this purpose, drainage projects and spillway chutes, as well as many baffle block chutes, were designed and constructed with the parallel sidewalls and trapezoidal shape using the U.S. Bureau of Reclamation (USBR) instructions. Three divergence ratios of b1/b2=1.45,1.75, and 2.45, a parallel sidewall of b1/b2=1, and also three geometry blocks including trapezoidal USBR, trihedral, and semicircle blocks were applied and tested in the hydraulic laboratory using a baffle chute with the slope of (2 : 1), (H : V). The material used in this study was sediment sand with a uniform grain size of d50 = 1.2 mm, 15 cm of thickness, and 2 m of length. The experiment was conducted with seven different discharges in lasting condition, and the flow characteristic and scour hole dimensions were measured. The results revealed that in comparison with the USBR blocks, changes in the baffle sidewall and block shape made an approximate 50% reduction in the maximum depth of the scour hole. Thus, increasing the divergence ratio from 1 to 2.45 had a significant effect on reducing the maximum depth and the topographic shape of the scour hole. According to the range mentioned in the literature for the Weber number, the scale effect was negligible for the chute with baffle blocks. Generally, it can be concluded that the sidewall changes also can make a reduction in the number of overbaffle blocks, causing a reduction in the construction cost

An empirical investigation on the effects of electronic banking on key customer relationship management

In recent years, there has been good progress on information and communication technology influencing businesses with a new emerging concept called customer relationship management (CRM) and it has made significant changes in electronic banking. The primary objective of this paper is to survey electronic banking effects on key CRM components in one of Iranian banks in city of Tehran, Iran. The survey designs a questionnaire and distributes it among some experts in one of selected regions and the results are verified based on t-student and Freedman tests. Results show that all electronic banking services influence on CRM. In addition, that there are no significant differences among effects of electronic services on CRM but each CRM component has different effects on electronic services. In fact, according to freedman test, improving customer relationship process is the most important factor followed by providing appropriate service for each customer, providing appropriate service on appropriate time for each customer and providing appropriate service by appropriate channel for each customer

Classification of Asthma Based on Nonlinear Analysis of Breathing Pattern.

Normal human breathing exhibits complex variability in both respiratory rhythm and volume. Analyzing such nonlinear fluctuations may provide clinically relevant information in patients with complex illnesses such as asthma. We compared the cycle-by-cycle fluctuations of inter-breath interval (IBI) and lung volume (LV) among healthy volunteers and patients with various types of asthma. Continuous respiratory datasets were collected from forty age-matched men including 10 healthy volunteers, 10 patients with controlled atopic asthma, 10 patients with uncontrolled atopic asthma, and 10 patients with uncontrolled non-atopic asthma during 60 min spontaneous breathing. Complexity of breathing pattern was quantified by calculating detrended fluctuation analysis, largest Lyapunov exponents, sample entropy, and cross-sample entropy. The IBI as well as LV fluctuations showed decreased long-range correlation, increased regularity and reduced sensitivity to initial conditions in patients with asthma, particularly in uncontrolled state. Our results also showed a strong synchronization between the IBI and LV in patients with uncontrolled asthma. Receiver operating characteristic (ROC) curve analysis showed that nonlinear analysis of breathing pattern has a diagnostic value in asthma and can be used in differentiating uncontrolled from controlled and non-atopic from atopic asthma. We suggest that complexity analysis of breathing dynamics may represent a novel physiologic marker to facilitate diagnosis and management of patients with asthma. However, future studies are needed to increase the validity of the study and to improve these novel methods for better patient management

Classification of Asthma Based on Nonlinear Analysis of Breathing Pattern

<div><p>Normal human breathing exhibits complex variability in both respiratory rhythm and volume. Analyzing such nonlinear fluctuations may provide clinically relevant information in patients with complex illnesses such as asthma. We compared the cycle-by-cycle fluctuations of inter-breath interval (IBI) and lung volume (LV) among healthy volunteers and patients with various types of asthma. Continuous respiratory datasets were collected from forty age-matched men including 10 healthy volunteers, 10 patients with controlled atopic asthma, 10 patients with uncontrolled atopic asthma, and 10 patients with uncontrolled non-atopic asthma during 60 min spontaneous breathing. Complexity of breathing pattern was quantified by calculating detrended fluctuation analysis, largest Lyapunov exponents, sample entropy, and cross-sample entropy. The IBI as well as LV fluctuations showed decreased long-range correlation, increased regularity and reduced sensitivity to initial conditions in patients with asthma, particularly in uncontrolled state. Our results also showed a strong synchronization between the IBI and LV in patients with uncontrolled asthma. Receiver operating characteristic (ROC) curve analysis showed that nonlinear analysis of breathing pattern has a diagnostic value in asthma and can be used in differentiating uncontrolled from controlled and non-atopic from atopic asthma. We suggest that complexity analysis of breathing dynamics may represent a novel physiologic marker to facilitate diagnosis and management of patients with asthma. However, future studies are needed to increase the validity of the study and to improve these novel methods for better patient management.</p></div

The mean ± SD values of the average and the coefficient of variation (CV) of inter-breath interval and lung volume series.

<p>The mean ± SD values of the average and the coefficient of variation (CV) of inter-breath interval and lung volume series.</p