Analysis of Kaba using Computed Tomography and 3D Laser Imaging Techniques

The Tenth Symposium on Polar Science/Poster presentations: [OA] Antarctic meteorites, Wed. 4 Dec. / Entrance Hall (1st floor), National Institute of Polar Researc

Dynamics of delayed piecewise linear systems

In this paper the dynamics of the controlled pendulum is investigated assuming backlash and time delays. The upper equilibrium of the pendulum is stabilized by a piecewise constant control force which is the linear combination of the sampled values of the angle and the angular velocity of the pendulum. The control force is provided by a motor which drives one of the wheels of the cart through an elastic teeth belt. The contact between the teeth of the gear (rigid) and the belt (elastic) introduces a nonlinearity known as "backlash" and causes the oscillation of the controlled pendulum around its upper equilibrium. The processing and sampling delays in the determination of the control force tend to destabilize the controlled system as well. We obtain conditions guaranteeing that the pendulum remains in the neighborhood of the upper equilibrium. Experimental findings obtained on a computer controlled inverted pendulum cart structure are also presented showing good agreement with the simulation results

Sampling Delay and Backlash in Balancing Systems

A mechanical model of a digital balancing system is constructed and its stability analysis is presented. This model considers experimental problems like backlash and sampling delay. The conditions of existence of stable stationary and periodic solutions are determined for the case of the system without delay. Phase diagrams and bifurcation diagrams are revealed after simulations and bifurcation analysis. Adding sampling delay to the system, the stability conditions are changed and above a critical value of the delay, the balancing is impossible. The stability conditions and the stability chart are determined again and the critical sampling delay is calculated versus the parameters describing the system

Backlash in balancing systems using approximate spring characteristics

A mechanical model of a balancing system is constructed and its stability analysis is presented. This model considers an interesting practical problem, the backlash. It appears in the system as a nonlinear spring characteristic with noncontinuous derivative. The upper equilibrium of the pendulum can be stabilized without backlash. Backlash causes oscillations around this equi- librium. Phase space diagrams are revealed based on simulations. Bifurca- tion analysis is carried out by the continuation method. The noncontinuous derivative of the spring characteristic causes problems during the calcula- tion, therefore different types of approximate characteristics are used. The conditions of the existence of stable stationary and periodic solutions are determined in case of the approximate systems and conclusions are obtained for the exact piecewise linear system

Efficacy and Safety of [¹⁷⁷Lu]Lu-DOTA-TATE in Adults with Inoperable or Metastatic Somatostatin Receptor-Positive Pheochromocytomas/Paragangliomas, Bronchial and Unknown Origin Neuroendocrine Tumors, and Medullary Thyroid Carcinoma: A Systematic Literature Review

Background: We have performed a systematic review to evaluate the efficacy and safety of [177Lu]Lu-DOTA-TATE, a radioligand therapy, in advanced somatostatin receptor-positive pheochromocytoma/paraganglioma (PPGL), thymic neuroendocrine tumor (NET), bronchial NET, unknown primary NET, or medullary thyroid carcinoma (MTC). Methods: Studies identified in PubMed from inception to 13 May 2021 must have assessed [177Lu]Lu-DOTA-TATE as a single agent and reported outcome data for the specific NET types of interest. Results: Two independent reviewers performed the screening and data extraction, resulting in 16 publications: PPGL (n = 7), bronchial NETs (n = 6; one also included NETs of unknown origin), and MTC (n = 3). Overall, [177Lu]Lu-DOTA-TATE offers encouraging antitumor activity (overall tumor response rates and disease control rates) across NET types. Safety was favorable with most adverse events mild to moderate in severity, transient, and consistent with those seen in patients with gastroenteropancreatic (GEP)-NETs. Conclusions: [177Lu]Lu-DOTA-TATE has been used effectively in clinical practice to treat NETs of non-GEP origin

Radiation detection and energy conversion in nuclear reactor environments by hybrid photovoltaic perovskites

Detection and direct power conversion of high energy and high intensity ionizing radiation could be a key element in next generation nuclear reactor safety systems and space-born devices. For example, the Fukushima catastrophe in 2011 could have been largely prevented if 1% of the reactor's remnant radiation (gamma-rays of the nuclear fission) were directly converted within the reactor to electricity to power the water cooling circuit. It is reported here that the hybrid halide perovskite methylammonium lead triiodide could perfectly play the role of a converter. Single crystals were irradiated by a typical shut-down gamma-spectrum of a nuclear reactor with 7.61 x 10(14) Bq activity exhibit a high-efficiency of gamma-ray to free charge carrier conversion with radiation hardening. The power density of 0.3 mW/kg of methylammonium lead triiodide at 50 Sv/h means a four times higher efficiency than that for silicon-based cells. The material was stable to the limits of the experiment without changing its performance up to 100 Sv/h dose rate and 57 Sv H*(10) ambient total gamma-dose. Moreover, the gamma-shielding performance of methylammonium lead triiodide was found to be superior to both ordinary and barite concrete