Influence of temperature on mechanical characteristics of 1018 low carbon steel estimated by ultrasonic non-destructive testing method

The temperature dependence of ultrasonic velocities propagated in low carbon steel 1018 has been investigated by the A-scan mode of the ultrasonic non-destructive testing method. Experimental results show that these velocities are linearly dependent on temperature of the carbon steel sample in the range of 0 to 50 °C. Based on the experimental velocities of the longitudinal wave and the shear one, mechanical characteristics of this carbon steel including Poisson's ratio (υ), Young’s modulus (E), shear modulus (G), and bulk modulus (K) have been calculated. These mechanical characteristics have also been linear response with respect to the increase of sample’s temperature. By using linear fitting approach, the temperature dependence coefficients of these mechanical characteristics have been analyzed and estimated to be 9.76×10-6/°C, −0.057 GPa/°C, −0.023 GPa/°C, and −0.038 GPa/°C for v, E, G, and K, respectively. It is concluded that the influence of the temperature on the mechanical properties of the carbon steels is necessary determined due to the improved accuracy of the ultrasonic testing method

Numerical Simulation of the Stability of Rock Mass around Large Underground Cavern

Geotechnical problems are complicated to the extent and cannot be expected in other areas since non-uniformities of existing discontinuous, pores in materials and various properties of the components. At present, it is extremely difficult to develop a program for tunnel analysis that considers all complicated factors. However, tunnel analysis has made remarkable growth for the past several years due to the development of numerical analysis method and computer development, given the situation that it was difficult to solve formula of elasticity, viscoelasticity, and plasticity for the dynamic feature of the ground when the constituent laws, yielding conditions of ground materials, geometrical shape and boundary conditions of the structure were simulated in the past. The stability of rock mass around an underground large cavern is the key to the construction of large-scale underground projects. In this paper, the stability analysis was carried out based on those parameters by using 2D FEM RS2 program. The calculated stress and displacements of surrounding rock and rock support by FEM analysis were compared with those allowable values. The pattern of deformation, stress state, and the distribution of plastic areas are analyzed. Finally, the whole stability of surrounding rock mass of underground caverns was evaluated by Rocscience - RS2 software. The calculated axial forces were far below design capacity of rock bolts. The strong rock mass strength and high horizontal to vertical stress ratio enhanced safe working conditions throughout the excavation period. Thus wide span caverns and the system of caverns could be stability excavated sedimentary rock during the underground cavern and the system of caverns excavation by blasting method. The new method provides a reliable way to analyze the stability of the caverns and the system of caverns and also will help to design or optimize the subsequent support. Doi: 10.28991/CEJ-2022-08-01-06 Full Text: PD

A sharp bound for the resurgence of sums of ideals

We prove a sharp upper bound for the resurgence of sums of ideals involving disjoint sets of variables, strengthening work of Bisui--H\`a--Jayanthan--Thomas. Complete solutions are delivered for two conjectures proposed by these authors. For given real numbers $a$ and $b$, we consider the set Res$(a,b)$ of possible values of the resurgence of $I+J$ where $I$ and $J$ are ideals in disjoint sets of variables having resurgence $a$ and $b$, respectively. Some questions and partial results about Res$(a,b)$ are discussed.Comment: 14 pages, 01 figur

Non-destructive Characteristics of Ultrasonic Waves in 1018 Low Carbon Steel

In this paper, the dependences of the velocities and the absorption coefficients of ultrasonic waves transmitted in 1018 low carbon steel on temperature ranging from 0$^{\circ}$C to 50$^{\circ}$C were investigated. It was shown that the velocities of the ultrasonic longitudinal wave and ultrasonic shear wave were decreased when the temperature increased. The transportation of the ultrasonic longitudinal wave and ultrasonic shear wave depends on temperature and its coefficient in a temperature range of (0 - 50 $^{\circ}$C) was estimated about 0.8 m/s.$^{\circ}$C and 0.44~m/s.$^{\circ}$C, respectively. These obtained results are in good agreement with the theoretical prediction. Furthermore, the absorption coefficients of the ultrasonic longitudinal wave were also studied

A Schrödinger Equation for Evolutionary Dynamics

We establish an analogy between the Fokker–Planck equation describing evolutionary landscape dynamics and the Schrödinger equation which characterizes quantum mechanical particles, showing that a population with multiple genetic traits evolves analogously to a wavefunction under a multi-dimensional energy potential in imaginary time. Furthermore, we discover within this analogy that the stationary population distribution on the landscape corresponds exactly to the ground-state wavefunction. This mathematical equivalence grants entry to a wide range of analytical tools developed by the quantum mechanics community, such as the Rayleigh–Ritz variational method and the Rayleigh–Schrödinger perturbation theory, allowing us not only the conduct of reasonable quantitative assessments but also exploration of fundamental biological inquiries. We demonstrate the effectiveness of these tools by estimating the population success on landscapes where precise answers are elusive, and unveiling the ecological consequences of stress-induced mutagenesis—a prevalent evolutionary mechanism in pathogenic and neoplastic systems. We show that, even in an unchanging environment, a sharp mutational burst resulting from stress can always be advantageous, while a gradual increase only enhances population size when the number of relevant evolving traits is limited. Our interdisciplinary approach offers novel insights, opening up new avenues for deeper understanding and predictive capability regarding the complex dynamics of evolving populations

A Schr\"odinger Equation for Evolutionary Dynamics

We establish an analogy between the Fokker-Planck equation describing evolutionary landscape dynamics and the Schr\"{o}dinger equation which characterizes quantum mechanical particles, showing how a population with multiple genetic traits evolves analogously to a wavefunction under a multi-dimensional energy potential in imaginary time. Furthermore, we discover within this analogy that the stationary population distribution on the landscape corresponds exactly to the ground-state wavefunction. This mathematical equivalence grants entry to a wide range of analytical tools developed by the quantum mechanics community, such as the Rayleigh-Ritz variational method and the Rayleigh-Schr\"{o}dinger perturbation theory, allowing us to not only make reasonable quantitative assessments but also explore fundamental biological inquiries. We demonstrate the effectiveness of these tools by estimating the population success on landscapes where precise answers are elusive, and unveiling the ecological consequences of stress-induced mutagenesis -- a prevalent evolutionary mechanism in pathogenic and neoplastic systems. We show that, even in a unchanging environment, a sharp mutational burst resulting from stress can always be advantageous, while a gradual increase only enhances population size when the number of relevant evolving traits is limited. Our interdisciplinary approach offers novel insights, opening up new avenues for deeper understanding and predictive capability regarding the complex dynamics of evolving populations

Pathological complete response and survival of HER2-positive invasive breast cancer following docetaxel, carboplatin, and trastuzumab neoadjuvant therapy: a Vietnamese experience

Introduction. Neoadjuvant chemotherapy for HER2-positive breast cancer consists of a chemotherapy regimen plus trastuzumab with or without pertuzumab. The use of trastuzumab has been shown to improve pathological complete response (pCR), disease-free survival (DFS), and overall survival (OS). Purposes: To evaluate the efficacy and safety of neoadjuvant docetaxel, carboplatin, and trastuzumab (TCH) in the treatment of HER2-positive breast cancer in Vietnamese patients.  Material and methods. This retrospective study reviewed stage II–III HER2-positive breast cancer patients who received neoadjuvant docetaxel, carboplatin, and trastuzumab (TCH) at the Vietnamese National Cancer Hospital. The primary endpoint was the pCR rate which was defined as the absence of invasive tumor in the breast and axillary nodes (ypT0/is, ypN0). The secondary endpoints were DFS, OS, and toxicities.  Results. The complete and partial clinical response of 51 patients were 33.3% and 58.8%, respectively. The pCR rate was 41.2%; there was a significantly higher response in cT1-2 patients compared to cT3-4 ones (61.1% vs. 39.3%, p = 0.033). Three-year estimated DFS and OS rates were 81.3% and 93.0%, respectively. Treatment was generally well tolerated. Grade 3/4 neutropenia and anemia were uncommon (21.6% and 7.8%). No symptomatic cardiac dysfunction occurred.  Conclusions. Neoadjuvant TCH, non-anthracycline chemotherapy with single anti-HER2 regimen achieved high efficacy, with a good pCR rate and favorable tolerability in stage II or III HER2-positive breast cancer patients

Characteristics of basal gastric juice in Helicobacter pylori-associated gastritis before and after eradication therapy

Purpose: To evaluate the characteristics of basal gastric juice in Helicobacter pylori-positive patients before and after Helicobacter pylori eradication therapy. Methods: This was a cross-sectional descriptive study on 150 gastritis patients admitted at the Hospital of Can Tho University of Medicine and Pharmacy. The patients were divided into 2 groups: study group (Helicobacter pylori gastritis patients) and control group (non-Helicobacter pylori gastritis patients). The pH, HCO3- concentration, and activities and concentrations of pepsin, lipase, and amylase were determined before and after treatment in study group. Results: Patients with abnormal gastric juice comprised 76 % of the study population. Mean gastric potential of hydrogen (pH) was 2.31 (range: 1.64 - 7.68), while median concentration of HCO3- was 4.06 mmol/L (range: 0 - 73.04 mmol/L). The concentrations of pepsin, lipase, and amylase were 8.93, 0.93 and 1.38 ppm, respectively. Activities of pepsin, lipase, and amylase were 2.23, 0.28 and 0.04 U/mL, respectively. After the successful eradication of Helicobacter pylori, pH and HCO3- levels decreased, and there were significant differences in activities of pepsin and lipase before and after treatment (p < 0.05). Moreover, the levels of these parameters differed between patients in whom successful eradication was achieved and those in whom eradication failed (p < 0.05). The concentrations and activities of pepsin and lipase were statistically different between pre-treatment and post-treatment stages in both successful and failed Helicobacter pylori eradication categories (p < 0.05). Conclusion: Basal gastric juice differs significantly between Helicobacter pylori-positive and Helicobacter pylori-negative patients. Intragastric ammonia produced by H. pylori may have a role in the increased pH of gastric juice