Continuum Modeling Methodology for Dynamic Behavior of Towers

A very common problem in Civil Engineering is the analysis and design of lattice structures. These types of structures generally consist of repetitive sections and have been utilized in the erection of transmission and communication towers, space roof trusses, solar energy collectors, and space platforms. Since lattice structures consist of a significantly large number of members and subsequently a large number of nodes, the classical discrete technique of analysis can be very expensive even on today\u27s modern computers. This study applies a rational approach which capitalizes on the repetitive nature of towers to develop the equivalent continuum model for the lattice structure. The continuum approach is based on equivalencing the strain and kinetic energies of the actual latticed tower with that of the equivalent continuum model. Introducing the kinematic assumption that the strain components of the lattice structure have linear variations in the plane of the tower cross section is the key step in obtaining correct expressions for the equivalent properties of the continuum model. Procedures for developing continuum models are presented along with the constitutive equations and strain expressions. The procedures are demonstrated by applying the continuum modeling approach to planar trusses, triangular towers with constant cross sections, triangular towers with variable cross sections, and towers with rectangular cross sections. Numerical results for static deflections and free vibration analysis of planar trusses and towers with triangular cross sections are presented, and they indicate the high accuracy of the continuum model solution. In addition, a numerical technique is developed to obtain member forces of the actual lattice structure from the continuum model results. Moreover, a comparison of computer times using the SAP IV finite element program to analyze the actual lattice structures versus the equivalent continuum model is presented. In general, the continuum approach when applied to the analysis of lattice structures demonstrates a significant savings in computer cost with a relatively insignificant loss in accuracy

A review of COVID-19 vaccines strategies and anti-vaxxers theories

In what is a global record time of getting the COVID-19 vaccines available within 11 months, the world has equally been faced with several myths and conspiracy theories dissuading the public from accepting vaccination as an important measure in the response to the pandemic. We reviewed the leading conspiracy theories and balanced these with the scientific basis of viral transmission and replication and the broad role of vaccination in tackling this challenge. We briefly examined the design of the leading vaccines, and provided recommendations for worldwide COVID-19 distribution, acceptance and use. Keywords: COVID-19, vaccine, anti-vaxxer, review   French Title: Un examen des stratégies de vaccins COVID-19 et des théories anti-vaxxers Dans ce qui est un temps record mondial pour obtenir les vaccins COVID-19 disponibles en 11 mois, le monde a également été confronté à plusieurs mythes et théories du complot dissuadant le public d'accepter la vaccination comme une mesure importante dans la réponse à la pandémie. Nous avons passé en revue les principales théories du complot et les avons équilibrées avec la base scientifique de la transmission et de la réplication virales et le rôle général de la vaccination dans la lutte contre ce défi. Nous avons brièvement examiné la conception des principaux vaccins et formulé des recommandations pour la distribution, l'acceptation et l'utilisation du COVID19 dans le monde. Mots clés: COVID-19, vaccin, anti-vaxxer, revu

Term Risk in Interest Rate Markets

Using a stylised financial system along with a systemic perspective thereof, the definition of an aggregated banking system that is default-free but vulnerable to liquidity risks is enabled. Within this setup, a consistent mathematical modelling framework for term interest rate systems is derived that enables the pricing and valuation of associated linear derivative instruments. It is then demonstrated that term rates may not be synthetically replicated, in general, which in turn enables the extraction and explanation of the genesis of term risk. These findings provide: (i) a rigorous understanding of the incomplete market paradigm that encapsulates inter-bank term rates and the risk management processes involved therein; and (ii) quantitative theoretical evidence against global interest rate reform proposals advocating for the replacement of term Libor (London inter-bank offered rate) reference rates with overnight rate-based alternatives

COVID-19 and lung cancer: risks, mechanisms and treatment interactions.

Cases of the 2019 novel coronavirus also known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue to rise worldwide. To date, there is no effective treatment. Clinical management is largely symptomatic, with organ support in intensive care for critically ill patients. The first phase I trial to test the efficacy of a vaccine has recently begun, but in the meantime there is an urgent need to decrease the morbidity and mortality of severe cases. It is known that patients with cancer are more susceptible to infection than individuals without cancer because of their systemic immunosuppressive state caused by the malignancy and anticancer treatments. Therefore, these patients might be at increased risk of pulmonary complications from COVID-19. The SARS-CoV-2 could in some case induce excessive and aberrant non-effective host immune responses that are associated with potentially fatal severe lung injury and patients can develop acute respiratory distress syndrome (ARDS). Cytokine release syndrome and viral ARDS result from uncontrolled severe acute inflammation. Acute lung injury results from inflammatory monocyte and macrophage activation in the pulmonary luminal epithelium which lead to a release of proinflammatory cytokines including interleukin (IL)-6, IL-1 and tumor necrosis factor-α. These cytokines play a crucial role in immune-related pneumonitis, and could represent a promising target when the infiltration is T cell predominant or there are indirect signs of high IL-6-related inflammation, such as elevated C-reactive protein. A monoclonal anti-IL-6 receptor antibody, tocilizumab has been administered in a number of cases in China and Italy. Positive clinical and radiological outcomes have been reported. These early findings have led to an ongoing randomized controlled clinical trial in China and Italy. While data from those trials are eagerly awaited, patients' management will continue to rely for the vast majority on local guidelines. Among many other aspects, this crisis has proven that different specialists must join forces to deliver the best possible care to patients

E2 strengths and transition radii difference of one-phonon 2+ states of 92Zr from electron scattering at low momentum transfer

Background: Mixed-symmetry 2+ states in vibrational nuclei are characterized by a sign change between dominant proton and neutron valence-shell components with respect to the fully symmetric 2+ state. The sign can be measured by a decomposition of proton and neutron transition radii with a combination of inelastic electron and hadron scattering [C. Walz et al., Phys. Rev. Lett. 106, 062501 (2011)]. For the case of 92Zr, a difference could be experimentally established for the neutron components, while about equal proton transition radii were indicated by the data. Method: Differential cross sections for the excitation of one-phonon 2+ and 3- states in 92Zr have been measured with the (e,e') reaction at the S-DALINAC in a momentum transfer range q = 0.3-0.6 fm^(-1). Results: Transition strengths B(E2;2+_1 -> 0+_1) = 6.18(23), B(E2; 2+_2 -> 0+_1) = 3.31(10) and B(E3; 3-_1 -> 0+_1) = 18.4(11) Weisskopf units are determined from a comparison of the experimental cross sections to quasiparticle-phonon model (QPM) calculations. It is shown that a model-independent plane wave Born approximation (PWBA) analysis can fix the ratio of B(E2) transition strengths to the 2+_(1,2) states with a precision of about 1%. The method furthermore allows to extract their proton transition radii difference. With the present data -0.12(51) fm is obtained. Conclusions: Electron scattering at low momentum transfers can provide information on transition radii differences of one-phonon 2+ states even in heavy nuclei. Proton transition radii for the 2+_(1,2) states in 92Zr are found to be identical within uncertainties. The g.s. transition probability for the mixed-symmetry state can be determined with high precision limited only by the available experimental information on the B(E2; 2+_1 -> 0+_1) value.Comment: 14 pages, 5 figures, submitted to Phys. Rev. C, revised manuscrip