An investigation of corium in Fukushima Daiichi Unit-1 accident.

The core melt composition resulting from the Fukushima Daiichi Unit1 Nuclear Power Plant (FD-U1) accident is essential for the corium characterization phase before decommissioning or handling of radioactive waste. Several models were applied by different research groups for the estimation of corium composition. In this paper, the investigation of the isotopic composition, and radioactivity of the radio-nuclides in the corium10 and 50 years post-accident were calculated using Monte Carlo code, MCNPX 2.7. The results showed that the estimated core materials inventory at reactor scram before core melt was about 123.97 ton, and after the formation of the corium melt was about 140.702 ton, which agrees with the predictions calculated using other models. Also, the total corium activity was about 6.046E+17 Bq and 1.89E+17 Bq 10 and 50 years post- accident, respectively. The radionuclide compositions in the corium are necessary for decommissioning plan of F-D-U1. Furthermore, RELAP/SCDAPSIM MOD3.4 code was used for the analysis of thermal performance of the FD-U1 reactor core starting from the time of the accident up to corium formation and slumping to the lower head of the reactor pressure vessel (RPV). Our analysis indicates that the hydrogen generation started on March11th, around 18:39. The results were compared with MELCOR code and OECD/NEA BSAF Phase I results, which were found in good agreement.

Aesthetic monitoring-based assessment of oncological safety of oncoplastic management of breast cancer: a multi-center research study.

BACKGROUND: Oncoplastic Breast surgeries (OBS) in breast cancer have evolved to preserve the cancerous breast rather than its amputation to improve postoperative cosmetic results. The lack of evidence to support the oncological safety and benefits of OBS is questionable. In this study, we evaluate various aspects of oncoplastic surgeries with a focused monitoring of aesthetic results and oncological safety. METHODS: This was a multi-center observational study focused on the statistics of data collected from cases who underwent oncoplastic surgeries from the cohort of breast cancer candidates at Mansoura University Hospitals/Egypt and King Faisal Medical Complex/KSA from January 2015 to June 2018. All data were analyzed carefully using SPSS v-26. RESULTS: Eighty cases who underwent different oncoplastic surgeries were included and reviewed for the aesthetic outcome and oncological safety. The recurrence rate was found to be 2.5%. The breast impact treatment scale assessment method was used to analyze the aesthetic outcomes, and average scores were accepted in 90% of patients. CONCLUSIONS: The oncoplastic breast surgeries are feasible and they had a high rate of oncological safety with the maintenance of good aesthetic outcomes and patient satisfaction.

Nonreciprocal elasticity and the realization of static and dynamic nonreciprocity.

The realization of the mechanical nonreciprocity requires breaking either the time-reversal symmetry or the material deformation symmetry. The time-reversal asymmetry was the commonly adopted approach to realize dynamic nonreciprocity. However, a static nonreciprocity requires-with no any other option-breaking the material deformation symmetry. By virtue of the Maxwell-Betti reciprocal theorem, the achievement of the static nonreciprocity seems to be conditional by the use of a nonlinear material. Here, we further investigate this and demonstrate a novel "nonreciprocal elasticity" concept. We investigated the conditions of the attainment of effective static nonreciprocity. We revealed that the realization of static nonreciprocity requires breaking the material deformation symmetry under the same kinematical and kinetical conditions, which can be achieved only and only if the material exhibits a nonreciprocal elasticity. By means of experimental and topological mechanics, we demonstrate that the realization of static nonreciprocity requires nonreciprocal elasticity no matter what the material is linear or nonlinear. We experimentally demonstrated linear and nonlinear metamaterials with nonreciprocal elasticities. The developed metamaterials were used to demonstrate that nonreciprocal elasticity is essential to realize static nonreciprocal-topological systems. The nonreciprocal elasticity developed here will open new venues of the design of metamaterials that can effectively break the material deformation symmetry and achieve, both, static and dynamic nonreciprocity.

Hinged-3D metamaterials with giant and strain-independent Poisson's ratios.

Current designs of artificial metamaterials with giant Poisson's ratios proposed microlattices that secrete the transverse displacement nonlinearly varies with the longitudinal displacement, and the Poisson's ratio depends on the applied strain (i.e., tailorable Poisson's ratio). Whereas metamaterials with tailorable Poisson's ratios would find many important applications, the design of a metamaterial with a giant Poisson's ratio that is constant over all the material deformation range has been a major challenge. Here, we develop a new class of bimaterial-3D-metamaterials with giant and strain-independent Poisson's ratios (i.e., Poisson's ratio is constant over the entire deformation range). The unit cell is 3D assembled of hinged-struts. Specially designed spherical hinges were utilized to give constant Poisson's ratios. This new class of metamaterials has been demonstrated by means of experimental and numerical mechanics. 15 material samples were 3D printed by Stereolithography (SLA) and tested. We revealed a robust anisotropy dependence of the Poisson's ratio. A giant negative Poisson's ratio of -16 was obtained utilizing a highly anisotropic unit cell of dissimilar materials and stiffnesses. Materials with giant and strain-independent Poisson's ratios provide a new class of artificial metamaterials, which would be used to optimize the performance of many existing devices, e.g., strain amplifiers and gauges.

Fluidity and phase transitions of water in hydrophobic and hydrophilic nanotubes.

We put water flow under scrutiny to report radial distributions of water viscosity within hydrophobic and hydrophilic nanotubes as functions of the water-nanotube interactions ([Formula: see text]), surface wettability (θ), and nanotube size (R) using a proposed hybrid continuum-molecular mechanics. Based on the computed viscosity data, [Formula: see text] phase diagram of the phase transitions of confined water in nanotubes is developed. It is revealed that water exhibits different multiphase structures, and the formation of one of these structures depends on [Formula: see text] R parameters. A drag of water flow at the first water layer is revealed, which is conjugate to sharp increase in the viscosity and formation of an ice phase under severe confinement (R ≤ 3.5 nm) and strong water-nanotube interaction conditions. A vapor/vapor-liquid phase is observed at hydrophobic and hydrophilic interfaces. A state of confinement is revealed at which water exhibits different multiphase structures under the same flow rate. The derived viscosity functions are used to accurately determine factors of flow enhancement/inhibition of confined water.

Reporting the Fatigue Life of 316L Stainless Steel Locking Compression Plate Implants: The Role of the Femoral and Tibial Biomechanics During the Gait.

In this study, the fatigue characteristics of femoral and tibial locking compression plate (LCP) implants are determined accounting for the knee biomechanics during the gait. A biomechanical model for the kinematics and kinetics of the knee joint during the complete gait cycle is proposed. The rotations of the femur, tibia, and patella about the knee joint during the gait are determined. Moreover, the patellar-tendon force (PT), quadriceps-tendon force (QT), the tibiofemoral joint force (TFJ), and the patellofemoral joint force (PFJ) through the standard gait cycle are obtained as functions of the body weight (BW). On the basis of the derived biomechanics of the knee joint, the fatigue factors of safety along with the fatigue life of 316L stainless steel femoral and tibial LCP implants are reported as functions of the BW and bone fracture location, for the first time. The reported results reveal that 316L stainless steel LCP implants for femoral surgeries are preferred for conditions in which the bone fracture is close to the knee joint and the BW is less than 80 kg. For tibial surgeries, 316L stainless steel LCP implants can be used for conditions in which the bone fracture is close to the knee joint and the BW is less than 100 kg. This study presents a critical guide for the determination of the fatigue characteristics of LCP implants. The obtained results reveal that the fatigue analyses should be performed on the basis of the body biomechanics to guarantee accurate designs of LCP implants for femoral and tibial orthopedic surgeries.