Flow simulation and investigating the effects of cutoff wall on the uplift pressure in earth dams

Since the construction of dam is significantly important both according to economic and safety aspects, it should be carefully assessed before construction. The use of available software is one of the evaluation and behavioral investigation methods. On this basis, we have investigated the effect of cutoff wall on the seepage flow, uplift pressure, etc, in the body of earth dam in Baft city through numerical modeling using the finite element method through GeoStudio software package. The results of this analysis indicate that the location and dimensions of cutoff wall significantly affects its performance on reducing the seepage flow. The soil type in terms of permeability is another important parameter and the results indicate that the one-time reduction of soil dam penetration reduces the seepage flow by 97%.Keywords: Earth dam, cutoff wall, soil permeability, GeoStudio software, uplift pressure

Supramolecular networks stabilise and functionalise black phosphorus

The limited stability of the surface of black phosphorus (BP) under atmospheric conditions is a significant constraint on the exploitation of this layered material and its few layer analogue, phosphorene, as an optoelectronic material. Here we show that supramolecular networks stabilised by hydrogen bonding can be formed on BP, and that these monolayer-thick films can passivate the BP surface and inhibit oxidation under ambient conditions. The supramolecular layers are formed by solution deposition and we use atomic force microscopy to obtain images of the BP surface and hexagonal supramolecular networks of trimesic acid and melamine cyanurate (CA.M) under ambient conditions. The CA.M network is aligned with rows of phosphorus atoms and forms large domains which passivate the BP surface for more than a month, and also provides a stable supramolecular platform for the sequential deposition of 1,2,4,5-tetrakis(4-carboxyphenyl)benzene to form supramolecular heterostructures

High electron mobility, quantum Hall effect and anomalous optical response in atomically thin InSe

A decade of intense research on two-dimensional (2D) atomic crystals has revealed that their properties can differ greatly from those of the parent compound. These differences are governed by changes in the band structure due to quantum confinement and are most profound if the underlying lattice symmetry changes. Here we report a high-quality 2D electron gas in few-layer InSe encapsulated in hexagonal boron nitride under an inert atmosphere. Carrier mobilities are found to exceed 103cm2V-1s-1and 104cm2V-1s-1at room and liquid-helium temperatures, respectively, allowing the observation of the fully developed quantum Hall effect. The conduction electrons occupy a single 2D subband and have a small effective mass. Photoluminescence spectroscopy reveals that the bandgap increases by more than 0.5eV with decreasing the thickness from bulk to bilayer InSe. The band-edge optical response vanishes in monolayer InSe, which is attributed to the monolayer's mirror-plane symmetry. Encapsulated 2D InSe expands the family of graphene-like semiconductors and, in terms of quality, is competitive with atomically thin dichalcogenides and black phosphorus.EU, EPSRC. The Royal Societ

Absolute choline tissue concentration mapping for prostate cancer localization and characterization using 3D (1) H MRSI without water-signal suppression

PURPOSE: Until now, (1) H MRSI of the prostate has been performed with suppression of the large water signal to avoid distortions of metabolite signals. However, this signal can be used for absolute quantification and spectral corrections. We investigated the feasibility of water-unsuppressed MRSI in patients with prostate cancer for water signal-mediated spectral quality improvement and determination of absolute tissue levels of choline. METHODS: Eight prostate cancer patients scheduled for radical prostatectomy underwent multi-parametric MRI at 3 T, including 3D water-unsuppressed semi-LASER MRSI. A postprocessing algorithm was developed to remove the water signal and its artifacts and use the extracted water signal as intravoxel reference for phase and frequency correction of metabolite signals and for absolute metabolite quantification. RESULTS: Water-unsuppressed MRSI with dedicated postprocessing produced water signal and artifact-free MR spectra throughout the prostate. In all patients, the absolute choline tissue concentration was significantly higher in tumorous than in benign tissue areas (mean +/- SD: 7.2 +/- 1.4 vs 3.8 +/- 0.7 mM), facilitating tumor localization by choline mapping. Tumor tissue levels of choline correlated better with the commonly used (choline + spermine + creatine)/citrate ratio (r = 0.78 +/- 0.1) than that of citrate (r = 0.21 +/- 0.06). The highest maximum choline concentrations occurred in high-risk cancer foci. CONCLUSION: This report presents the first successful water-unsuppressed MRSI of the whole prostate. The water signal enabled amelioration of spectral quality and absolute metabolite quantification. In this way, choline tissue levels were identified as tumor biomarker. Choline mapping may serve as a tool in prostate cancer localization and risk scoring in multi-parametric MRI for diagnosis and biopsy procedures

In vivo MR spectroscopic imaging of the prostate, from application to interpretation

Contains fulltext : 177776.pdf (publisher's version ) (Open Access)Proton magnetic resonance spectroscopic imaging (1H MRSI) enables non-invasive assessment of certain metabolites in the prostate gland. Several studies have demonstrated that this metabolic information, in combination with anatomical information from T2-weighted MR imaging significantly improves prostate cancer detection, localization and disease characterization. The technology of 1H MRSI is continuously evolving with improvements of hardware and acquisition methods. Recently, 31P and 13C MRSI of the prostate have regained new interest after a dormant period of decades. This review focuses on recent technical progress of in vivo1H MRSI of the prostate, in particular those that enhance clinical applicability at 3T with respect to commonly used techniques to examine the prostate. These developments consist of higher magnetic field strengths, and better MR coils and acquisition techniques. Besides the improvements for 1H MRSI, the developments and opportunities for 31P and 13C MRSI for the prostate are reviewed. Finally, we briefly review 13C MRS of the prostate, in particular the new possibilities with hyperpolarized substrates

Simple and broadly applicable automatic quality control for 3D H-1 MR spectroscopic imaging data of the prostate

Contains fulltext : 202605.pdf (publisher's version ) (Closed access