Time-dependent Analysis of Jet-grouted Tunnels in Difficult Ground Conditions

textIn this study, excavation of jet-grouted tunnels in ground with strong time-dependent behavior is analyzed. The constant growth of population has led to a constant increase in the price of lands and thus infrastructures. Underground alternatives are becoming more economical. Furthermore, advances in the construction technology have made it feasible to construct tunnels in difficult ground conditions. By providing a grouted arch ahead of the tunnel face, jet-grouting has proved effective for the stability and performance of tunnels in difficult conditions. Given the limited depth of jet-grouting into the face, the jet-grouted arch is loaded soon after installation, when the rigidity of the grouted material is growing significantly. The simultaneous loading and hardening of the jet-grouting makes the tunnel response depend on the excavation rate. Furthermore, in difficult tunneling conditions, the ground material is associated with highly viscous behavior. This behavior is synonymous with delayed deformation depending on the level and duration of the ground loading by the tunnel excavation. In order to show the importance of the time-dependent behaviors, the full-face and the sequential excavation method are compared using three-dimensional and two-dimensional finite element analyses. First, a three-dimensional model is constructed and its results are validated against available analytical solutions for time-independent behaviors. The hardening of the jet-grouting is then introduced into the model by embedding jet-grouting elements through the analysis. In order to account for the ground viscous behavior, an advanced viscoplastic constitutive model is adopted, numerically implemented in FORTRAN, and used in conjunction with finite element software ABAQUS. The excavation methods are compared for the well documented study case of Tartaiguille tunnel. The results indicate that the full-face method outperforms the sequential method in the studied case by installing the tunnel invert closer to the face. The two-dimensional analysis of the tunnel is conducted by using the convergence-confinement method. To this end, a new approach is introduced to use the method for tunnels in time-dependent conditions. The effect of the jet-grouting hardening and the ground viscous behavior is characterized within the new approach by deriving the ground convergence curves. The reverse dependency of these mechanisms on the tunnel advance rate leads to an optimum advance rate, at which minimum tunnel convergence develops.Civil, Architectural, and Environmental Engineerin

A unit-based symbolic execution method for detecting memory corruption vulnerabilities in executable codes

Memory corruption is a serious class of software vulnerabilities, which requires careful attention to be detected and removed from applications before getting exploited and harming the system users. Symbolic execution is a well-known method for analyzing programs and detecting various vulnerabilities, e.g., memory corruption. Although this method is sound and complete in theory, it faces some challenges, such as path explosion, when applied to real-world complex programs. In this paper, we present a method for improving the efficiency of symbolic execution and detecting four classes of memory corruption vulnerabilities in executable codes, i.e., heap-based buffer overflow, stack-based buffer overflow, use-after-free, and double-free. We perform symbolic execution only on test units rather than the whole program to avoid path explosion. In our method, test units are considered parts of the program's code, which might contain vulnerable statements and are statically identified based on the specifications of memory corruption vulnerabilities. Then, each test unit is symbolically executed to calculate path and vulnerability constraints of each statement of the unit, which determine the conditions on unit input data for executing that statement or activating vulnerabilities in it, respectively. Solving these constraints gives us input values for the test unit, which execute the desired statements and reveal vulnerabilities in them. Finally, we use machine learning to approximate the correlation between system and unit input data. Thereby, we generate system inputs that enter the program, reach vulnerable instructions in the desired test unit, and reveal vulnerabilities in them. This method is implemented as a plugin for angr framework and evaluated using a group of benchmark programs. The experiments show its superiority over similar tools in accuracy and performance

Niosomal Formulation for Co-Administration of Hydrophobic Anticancer Drugs into MCF-7 Cancer Cells

Introduction: Designing and developing drug delivery systems has received tremendous attention during the last decade. The treatment of cancer cells is a complicated process due to the existence of different biological pathways. Therefore, the co-delivery of different drugs could have a synergic effect on the treatment process.Materials and Methods: In this study, different types of span (20, 60, 80) and cholesterol were utilized to formulate tamoxifen/curcumin co-loaded niosomes as a drug carrier system for breast cancer chemotherapy. Niosome characterization was performed through a set of instrument analysis techniques including scanning electron microscopy (SEM) and dynamic light scattering. Release behavior was studied by dialysis method at (pH = 5, 7.4). The stability was monitored during two months storage at two temperatures (4 and 25 °C). Cytotoxicity activity of the best niosomal formulation were assessed on MCF-7 cells, using MTT assay.Results: The optimal niosomal formulation with span 80 and lipid-to-drug molar ratio of 20 was selected, with maximum encapsulation of both drugs and minimum size. Drug release behavior at physiological pH (7.4) (with significant drug release under acidic conditions (pH = 5) and storage stability of up to 2 weeks with little change in drug efficacy and measurement makes it a proper candidate for breast cancer treatment.Conclusion: Finally, the results of this study showed the importance of creating highly biocompatible formulations, allowing the simultaneous transfer of two drugs with controlled release to cancer cells which could improve the chemotherapy process with the synergistic effect of the two drugs

Geomechanical analysis of a welding salt layer and its effects on adjacent sediments

AbstractWe simulate welding of the source layer of a salt diapir with a forward finite-element model and study stresses and deformation in the salt layer and the diapir, as well as in their adjacent sediments. Welded salt layers are abundant in mature salt basins, where most or all of the salt has withdrawn into diapirs. However, there is little understanding of the stress field in these layers and their adjacent sediments. We show that salt flow along the source layer leads to significant stress anomalies inside the layer and in adjacent sediments. In the source layer, salt pressure becomes higher than overburden stress in nearly welded areas and becomes lower than overburden stress in adjacent thicker areas. When the source layer welds, stresses increase significantly in sediments near the weld tip, which helps compaction of these sediments and possibly their fracturing and faulting. Our model illustrates that all sediments overlying the weld experience this stress increase and the associated material changes as the weld tip propagates along the weld. We present natural examples fitting our predictions and discuss the importance of our results for the exploration, characterization, and production of reservoirs near welded salt layers

Investigation of Flow Field in a Typical Hypersonic Wind Tunnel over a Standard Mode

In order to start designing a new hypersonic wind tunnel, it is important to have a pre-view about physical phenomena in a typical Hypersonic Wind Tunnel (HWT). In present research, it is tried to view phenomenologically the aerodynamics of flow in a typical HWT by Computational Fluid Dynamics (CFD). The considered HWT consists of a curved nozzle in nominal Mach number 12, free-jet type test section, a test model and a convergent-divergent diffuser. Aerodynamics of flow in the nozzle exit and test section, conical shock wave system in the diffuser and flow over a standard model (HB-2) are investigated. A method is introduced for numerical simulation of capturing the free shear layer in free-jet test section based on the vorticity distribution of flow. The aerodynamics behavior of HB-2 model is investigated in various Mach numbers and flow domains. The results make a better view of some aerodynamic phenomena in a free-jet type test section of wind tunnel that are rarely considered. This research is conducted towards the project of designing and manufacturing the industrial hypersonic wind tunnel for Qadr Aerodynamic research Center

Down-regulation of miR-135b in colon adenocarcinoma induced by a TGF-β receptor I kinase inhibitor (SD-208).

OBJECTIVES Transforming growth factor-β (TGF-β) is involved in colorectal cancer (CRC). The SD-208 acts as an anti-cancer agent in different malignancies via TGF-β signaling. This work aims to show the effect of manipulation of TGF-β signaling on some miRNAs implicated in CRC. MATERIALS AND METHODS We investigated the effects of SD-208 on SW-48, a colon adenocarcinoma cell line. The cell line was treated with 0.5, 1 and 2 μM concentrations of SD-208. Then, the xenograft model of colon cancer was established by subcutaneous inoculation of SW-48 cell line into the nude mice. The animals were treated with SD-208 for three weeks. A quantitative real-time PCR was carried out for expression level analysis of selected oncogenic (miR-21, 31, 20a and 135b) and suppressor-miRNAs (let7-g, miR-133b, 145 and 200c). Data were analyzed using the 2-∆∆CT method through student's t-test via the GraphPad Prism software. RESULTS Our results revealed that SD-208 could significantly down-regulate the expression of one key onco-miRNA, miR-135b, in either SW-48 colon cells (P=0.006) or tumors orthotopically implanted in nude mice (P=0.018). Our in silico study also predicted that SD-208 could modulate the expression of potential downstream tumor suppressor targets of the miR135b. CONCLUSION Our data provide novel evidence that anticancer effects of SD-208 (and likely other TGF-β inhibitors) may be owing to their ability to regulate miRNAs expression

Sequestration of heavy metals in the soil and leaves of Eucalyptus Micro theca, Cupressus arizonica and Robinia Pseudo Acasia around Ilam city’s cement plant

زمينه و اهداف: گياه­پالايي فلزات­ سنگين از مكان­هاي آلوده مي­تواند در خروج فلزات سنگين از خاك بدون صرف هزينه ­هاي از منطقه مؤثر باشد. هدف از انجام اين مطالعه بررسي ميزان ترسيب کادميوم، روي، سرب و منگنز در برگ و خاک گونه­هاي اکاليپتوس، سرو­سيمين و اقاقيا که در حاشيه کارخانه­سيمان ايلام کاشت شده­ اند مي­باشد. مواد و روش­ها: ميزان فلزات را در برگ و همچنين در دو عمق 10-0 و 20-10 سانتي متري خاک در 3 گونه مورد بررسي، توسط دستگاه جذب­اتم اندازه­گيري­شد. علاوه­بر­اين ميزان فلزات ترسيب­شده در الکتروفيلتر کارخانه نيز اندازه­ گيري­شد. از آناليز واريانس يک­طرفه و آزمون دانکن جهت مقايسه ميانگين­ها استفاده­ شد. يافته­ ها: نتايج نشان­داد که کادميوم، روي، سرب و منگنز ترسيب شده در الکتروفيلتر بيشتر از ميزان ترسيب اين عناصر در خاک و برگ گونه­هاي مورد بررسي مي­باشد. نتايج ترسيب فلزات در خاک به گونه­اي بود که در هر 3­گونه با افزايش عمق­خاک ميزان ترسيب سرب کاهش مي­يابد. بيشترين ميزان ترسيب کادميوم و روي هم در خاک و هم در برگ در گونه اقاقيا مشاهده­شد درحاليکه مقادير ترسيب اين دو عنصر هم در خاک و هم در برگ در 2 گونه اکاليپتوس و سروسيمين نزديک به هم بود. بيشترين ترسيب سرب و منگنز در خاک در هر دو عمق و همچنين در برگ، در گونه اکاليپتوس مشاهده­شد. از­طرفي­ديگر کمترين ميزان ترسيب سرب و منگنز را در هر دو عمق و همچنين در برگ، در گونه سرو­سيمين را داشت. نتيجه­ گيري: گونه ­هاي اکاليپتوس و اقاقيا ترسيب بيشتري از فلزات­سنگين داشتند و گونه­ هايي مناسب جهت کاشت و توسعه فضاي سبز در حاشيه کارخانه مي­باشند.Background and Aims: Phytoremediation of heavy metals from polluted sites could be an efficient and cost-effective alternative in removing heavy metals from soil. This study aimed to investigate the sequestration of Cd, Zn, Pb and Mn in the leaves and soil of Eucalyptus Micro theca, Cupressus arizonica Green and Robinia Pseudo Acasia, which have been planted around the Cement factory of Ilam.Materials and methods: Atomic absorption spectrometry was used to measure the accumulation of metals in leaves and in the soil at a depth of 0-10 and 10-20 cm in three species as well. Furthermore, the amounts of precipitated metals in Electro filter of factory were measured.Results: The results showed that Cd (0.55 mg/kg), Zn (3.92 mg/kg), Pb (40.25 mg/kg) and Mn (3.74 mg/ kg) sequestration occurred in electro filter; which were totally more than the amounts of them in soils and leaves of tree species. Results of metals sequestration in the soil revealed that increasing soil depth leads to decrease of Pb sequestration rate in all three species. The most sequestration of Cd and Zn both in the soil and leaves were observed in Robinia Pseudo Acasia. Likewise, the most sequestration of Pb and Mnin the soil at both depth and also in leaves were observed in Eucalyptus microtheca.Conclusion: Eucalyptus microtheca and Robinia Pseudo Acasia demonstrated the most sequestration of heavy metals, and thus are suitable species for planting and green space development around the factory

Relationship of Spirituality with Morbidity and Mortality in Patients with Coronary Artery Disease undergoing CABG Surgery at Shariati Hospital

For downloading the full-text of this article please click here.Background and Objective: Coronary artery disease is the leading cause of death in most countries. Although the relationship between spirituality and health has been confirmed in various studies, the relation in this specific case has not been investigated. Therefore, the present study was conducted to investigate the relationship of spirituality with morbidity and mortality in patients with coronary artery disease who underwent CABG surgery.Method: This cross-sectional study was performed on patients with coronary artery disease who had undergone CABG at Dr. Shariati Hospital in Tehran over the time period from December 2012 to December 2013. The data collection tools were a data gathering checklist based on patients' records and respective physician's confirmation and the Spirituality questionnaire (Hall and Edwards, 1996). Data were analyzed using Mann-Whitney, Kruskal-Wallis, and Spearman correlation coefficient. All ethical issues were observed in this study and the authors of the article have not reported any conflicts of interest.Results: The findings of the relationship between the six subscales of spirituality with morbidity and mortality showed that with an increase in the median score of disappointment subscale, the incidence of infection, tamponade, PVC and AF increased and by increasing the median score of awareness subscale, the incidence rate decreased (P<0.05). There was a significant positive correlation between the hospital stay and disappointment subscale (P=0.003, r=0.291). Mortality also decreased in patients who were more knowledgeable (p<0.05).Conclusion: The results of the research indicate that spirituality correlates with the incidence of morbidity and mortality after CABG surgery. Therefore, effective solutions such as considering the spiritual issues in the patients' treatment process and training appropriate psychological techniques should be used to expedite their recovery.For downloading the full-text of this article please click here.Please cite this article as: Bagheri J, Shayan N, BagheriM.M, Heidari M.Relationship of Spirituality with Morbidity and Mortality in Patients with Coronary Artery Disease undergoing CABG Surgery at Shariati Hospital. J Res Relig Health. 2019; 5(1): 76- 86. doi:https://doi.org/10.22037/jrrh.v5i1.17956

Study on the fouling behavior of HDPE/PE-g-MA/EVA blend membrane fabricated via thermally induced phase separation method

In this study, neat HDPE and HDPE/PE-g-MA/EVA blend membranes were fabricated via thermally induced phase separation (TIPS) method and their fouling behaviors were examined using filtration of BSA protein. Membranes were characterized using FESEM, AFM, ATR-FTIR analyses and porosity measurement. Fouling behavior of membranes was analyzed using the resistance-in-series (RIS), classic and combined pore blocking models. The results of RIS model revealed that the magnitude of inherent, reversible and irreversible resistances decreased from 0.611 ×1013m-1 and ,1.578 ×1013m-1 and 0.525 ×1013m-1 for the neat membrane to 0.237 ×1013m-1, 0.789 ×1013m-1 and 0.154×1013m-1 for the blend membrane, respectively. None of the classical Hermia’s models were able to accurately predict fouling during the entire filtration run. The results obtained from the combined pore blocking model indicated that the combined cake formation-intermediate blocking model provided good prediction of fouling mechanism for both the membranes. However, comparison between fitted parameters showed that much greater fouling occurred for pure HDPE membrane. The key reasons for such different fouling behaviors were mainly attributed to the difference in hydrophobicity as well as the distribution of pore size on the surface of the pure and blend membranes

Dating submarine landslides using the transient response of gas hydrate stability

Submarine landslides are prevalent on the modern-day seafloor, yet an elusive problem is constraining the timing of past slope failure. We present a novel age-dating technique based on perturbations to underlying gas hydrate stability caused by slide-impacted seafloor changes. Using three-dimensional (3-D) seismic data, we mapped an irregular bottom simulating reflection (BSR) underneath a submarine landslide in the Orca Basin, Gulf of Mexico. The irregular BSR mimics the pre-slide seafloor geometry rather than the modern bathymetry. Therefore, we suggest that the gas hydrate stability zone (GHSZ) is still adjusting to the post-slide sediment temperature. We applied transient conductive heat-flow modeling to constrain the response of the GHSZ to the slope failure, which yielded a most likely age of ca. 8 ka, demonstrating that gas hydrate can respond to landslides even on multimillennial time scales. We further provide a generalized analytical solution that can be used to remotely date submarine slides in the absence of traditional dating technique