227 research outputs found

    Investigating the Influence of Penetration Length of Cut-off Wall on its Dynamic Interaction with Core and Foundation of Earth Dam

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    Seepage and flow of water in the soil is one of the most important issue and effective elements in designing embankment dams. One of the methods to control seepage in alluvial foundation of earth dams is to use a plastic concrete cutoff-wall. For better seepage control, the cutoff-wall extends inside the clayey core as the one of common method of connection of cut-off wall and the core. Due to the stiffness difference of the core material and cutoff-wall, and also due to geological situation, physical and mechanical properties of rock and foundation, interaction of core and foundation with cut-off wall in different static and dynamic load cases is very considerable. Failure of cut-off wall occurs in cut-off wall and core joint.  So the study of their interaction, especially during an earthquake is very important. Karkheh dam cut-off wall with an area of about 150000 m2 is chosen for this study. FLAC software has been used to study the effect of cutoff-wall penetration length variation, inside the clay core of Karkheh earth dam under dynamic loading.  In numerical analysis of Karkheh earth dam model, all construction stages and seepage through dam are modelled. The model is first calibrated according to the results obtained from the dam instrumentations. After calibrating, according to available seismic studies of region, a suitable acceleration was selected and applied to the model. In this research, in order to find the optimum length, the effect of 0, 5, 10, 15 and 20 meters penetration length of cut-off wall in aforementioned conditions has been investigated. The results of the numerical study showed that the horizontal displacement and the maximum shear strain in the cutoff-wall is occurred adjacent to the clay core and the interface of core and foundation is a critical point for the cut-off wall, and also the stress in cut off wall joint increases with the elongation of penetration depth of the wall

    Retrograde intrarenal surgery versus shock wave lithotripsy for renal stones smaller than 2 cm: A randomized clinical trial

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    Purpose: To compare outcomes of retrograde intrarenal surgery (RIRS) with extracorporeal shock wave lithotripsy (SWL) for stones � 2 cm. Materials and Methods: Patients who were diagnosed with kidney stones of � 2 cm underwent RIRS or SWL in a parallel group randomized clinical trial with balanced randomization 1:1 from 2011 to 2014. The primary outcome of interest was stone free rate after a single session intervention. Patients were evaluated by ultrasonography and KUB at 1 and 3 months after the intervention for the presence of residual stone by a radiologist who was blinded to the study. Results: The stone free rate one month after a single session intervention in the RIRS group was higher than the SWL group (90% versus 75%, P = .03). The success rates after two sessions of RIRS versus SWL were 96.7% versus 88.3% respectively. (P = .08) Patients in the RIRS group had significantly lower postoperative visual analogue pain score compared to the SWL group (5.2 ± 2.8 versus 3.1 ± 2.7, P < .001). Steinstrasse formation and renal hematoma were observed in 4 and one patient in the SWL group versus no patient in the RIRS group. Postoperative hospital stay was significantly shorter in the SWL group (6.7 ± 1.3 versus18.9 ± 4.3 hours, P < .001). Conclusion: The RIRS procedure is a safe treatment option for renal stones of �2cm with less pain and higher success rate at first session compared to SWL

    Numerical and experimental analysis of a hybrid material acoustophoretic device for manipulation of microparticles.

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    Acoustophoretic microfluidic devices have been developed for accurate, label-free, contactless, and non-invasive manipulation of bioparticles in different biofluids. However, their widespread application is limited due to the need for the use of high quality microchannels made of materials with high specific acoustic impedances relative to the fluid (e.g., silicon or glass with small damping coefficient), manufactured by complex and expensive microfabrication processes. Soft polymers with a lower fabrication cost have been introduced to address the challenges of silicon- or glass-based acoustophoretic microfluidic systems. However, due to their small acoustic impedance, their efficacy for particle manipulation is shown to be limited. Here, we developed a new acoustophoretic microfluid system fabricated by a hybrid sound-hard (aluminum) and sound-soft (polydimethylsiloxane polymer) material. The performance of this hybrid device for manipulation of bead particles and cells was compared to the acoustophoretic devices made of acoustically hard materials. The results show that particles and cells in the hybrid material microchannel travel to a nodal plane with a much smaller energy density than conventional acoustic-hard devices but greater than polymeric microfluidic chips. Against conventional acoustic-hard chips, the nodal line in the hybrid microchannel could be easily tuned to be placed in an off-center position by changing the frequency, effective for particle separation from a host fluid in parallel flow stream models. It is also shown that the hybrid acoustophoretic device deals with smaller temperature rise which is safer for the actuation of bioparticles. This new device eliminates the limitations of each sound-soft and sound-hard materials in terms of cost, adjusting the position of nodal plane, temperature rise, fragility, production cost and disposability, making it desirable for developing the next generation of economically viable acoustophoretic products for ultrasound particle manipulation in bioengineering applications

    Comparing high-resolution gridded precipitation data with satellite rainfall estimates of TRMM_3B42 over Iran

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    To evaluate satellite rainfall estimates of Tropical Rain Measurement Mission (TRMM) level 3 output (3B42) (TRMM_3B42) over Iran (20&deg;–45&deg; N, 40&deg;–65&deg; E), we compared these data with high-resolution gridded precipitation datasets (0.25&deg;&times;0.25&deg; latitude/longitude) based on rain gauges (Iran Synoptic gauges Version 0902 (IS0902)). Spatial distribution of mean annual and mean seasonal rainfall in both IS0902 and TRMM_3B42 from 1998 to 2006 shows two main rainfall patterns along the Caspian Sea and over the Zagros Mountains. Scatter plots of annual average rainfall from IS0902 versus TRMM_3B42 for each 0.25&deg;&times;0.25&deg; grid cell over the entire country (25&deg;–40&deg; N, 45&deg;–60&deg; E), along the Caspian Sea (35&deg;–40&deg; N, 48&deg;–56&deg; E), and over the Zagros Mountains (28&deg;–37&deg; N, 46&deg;–55&deg; E) were derived. For the entire country, the Caspian Sea region, and the Zagros Mountains, TRMM_3B42 underestimates mean annual precipitation by 0.17, 0.39, and 0.15 mm day<sup>&minus;1</sup>, respectively, and the mean annual rainfall spatial correlation coefficients are 0.77, 0.57, and 0.75, respectively. The mean annual precipitation temporal correlation coefficient for IS0902 and TRMM_3B42 is ~0.8 in the area along the Zagros Mountains, and ~0.6 in the Caspian Sea and desert regions

    Genetic diversity of Mahisefid (Rutilus frisii kutum Kamensky 1901) in different rivers of the south Caspian Sea using PCR-RFLP

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    Mahisefid is the most popular fish in Iran with the highest economic value. The analysis of mitochondrial DNA has been extensively used as a marker for population genetic studies and is a powerful tool in studies of gene flow and evolutionary biology. Two hundred ninety four samples were collected from Sefid Rud River (100), Lamir River (98), Shir Rud River (48) and Tajan River (48) during spawning season. Out of 24 enzymes tested, four enzymes, namely TasI, HaeIII, HinfI and HincII were selected for this study. In the present study, the haplotype and nucleotide diversity of Mahisefid in four important rivers where fingerlings are produced, were carried out by using PCR-RFLP at mtDNA ND5/6 region. A total of 20 haplotypes were studied so that AAAA and BAAA haplotypes had the most frequency. The average haplotype frequency of AAAA and BAAA haplotypes were 29.93% and 27.55%, respectively. The maximum nucleotide diversity was 0.94%, the minimum was 0.80% and the average was 0.88%. Divergence between Lamir and Sefid Rud River and Shir Rud was 0.2% and between Lamir and Tajan, and Shir Rud River it was 0.1%. The average evolutionary distance was 0.015. The maximum evolutionary distance was 0.294 between ADAA and AAAB, ABAB and BDBA, BBAA and AABB. The average number of bases surveyed was 121.2 and the average number of fragments was 30.30. The study suggests that there was a low genetic variability in four populations of Mahisefid in the south of Caspian Sea. Mahisefid population can be divided into two main clusters, the first clade consists of Shir Rud River and Lamir River populations and the second clade consists of Tajan River and Sefid Rud River populations. The clustering of Mahisefid populations was not in accordance with their geographical areas or river systems

    Drawing inferences for high‐dimensional linear models: A selection‐assisted partial regression and smoothing approach

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    Drawing inferences for high‐dimensional models is challenging as regular asymptotic theories are not applicable. This article proposes a new framework of simultaneous estimation and inferences for high‐dimensional linear models. By smoothing over partial regression estimates based on a given variable selection scheme, we reduce the problem to low‐dimensional least squares estimations. The procedure, termed as Selection‐assisted Partial Regression and Smoothing (SPARES), utilizes data splitting along with variable selection and partial regression. We show that the SPARES estimator is asymptotically unbiased and normal, and derive its variance via a nonparametric delta method. The utility of the procedure is evaluated under various simulation scenarios and via comparisons with the de‐biased LASSO estimators, a major competitor. We apply the method to analyze two genomic datasets and obtain biologically meaningful results.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151307/1/biom13013.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151307/2/biom13013-sup-0001-SuppData.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151307/3/biom13013_am.pd
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