Parametric vision simulation study, part 2 Final report

Effects of landing site redesignation on visibility during manned lunar landin

Note: Utilizing Pb(Zr 0.95Ti 0.05)O₃ Ferroelectric Ceramics to Scale Down Autonomous Explosive-Driven Shock-Wave Ferroelectric Generators

Further miniaturization of recently designed autonomous ferroelectric generators (FEGs) S. I. Shkuratov, J. Baird, and E. F. Talantsev, Rev. Sci. Instrum. 82, 086107 (2011), which are based on the effect of explosive-shock-wave depolarization of poled ferroelectrics is achieved. The key miniaturization factor was the utilization of high-energy density Pb(Zr0.95Ti0.05)O3 (PZT 955) ferroelectric ceramics as energy-carrying elements of FEGs instead of the previously used Pb(Zr0.52Ti0.48)O3 (PZT 5248). A series of experiments demonstrated that FEGs based on smaller PZT 955 ferroelectric elements are capable of producing the same output voltage as those based on PZT 5248 elements twice as large. It follows from the experimental results that the FEG output voltage is directly proportional to the thickness of PZT 955 samples. A comparison of the operation of FEGs based on PZT 955 and on PZT 5248 ferroelectrics is presented

The Depolarization of Pb(Zr0.52Ti0.48)O₃ Ferroelectrics by Cylindrical Radially Expanding Shock Waves and Its Utilization for Miniature Pulsed Power

The effects of depolarization of Pb(Zr0.52Ti0.48)O3 (PZT 52/48) poled ferroelectrics by cylindrical radially expanding shock waves propagated along and across the polarization vector P0 were experimentally detected. Miniature (total volume 100 cm3) autonomous generators based on these effects were capable of producing output voltage pulses with amplitudes up to 25 kV and output energies exceeding 1 J

Effect of Shock Front Geometry on Shock Depolarization of Pb(Zr 0.52Ti 0.48)O₃ Ferroelectric Ceramics

By use of experimentation, we detected a shock wave geometry effect on the depolarization of poled PbZr0.52Ti0.48)O3 Z(PZT 52/48) ferroelectrics. It follows from the experimental results that shock front geometry is one of key parameters in the shock depolarization of PZT 5248 ferroelectrics. This shock depolarization effect forms a fundamental limit to miniaturization of explosive-driven shock-wave ferroelectric generators (FEGs). Based on obtained experimental results, we developed miniature generators that reliably produce pulsed voltages exceeding 140 kV

Note: Miniature 120-KV Autonomous Generator Based on Transverse Shock-Wave Depolarization of Pb(Zr0.52Ti0.48)O₃ Ferroelectrics

The design of autonomous ultrahigh-voltage generators with no moving metallic parts based on transverse explosive shock wave depolarization of Pb(Zr0.52Ti0.48)O3 (PZT 5248) poled ferroelectrics was explored and studied. It follows from experimental results that the output voltage produced by the shock-wave ferroelectric generators (FEGs) is directly proportional to the number of PZT 5248 elements connected in series. It was demonstrated that miniature FEGs (volume less than 180 cm3) were capable of reliably producing output voltage pulses with amplitudes exceeding 120 kV which is the record reported in open literature

Electric Breakdown of Longitudinally Shocked Pb(Zr₀.₅₂Ti₀.₄₈)O₃ Ceramics

Electric breakdown of longitudinally-shock-compressed Pb(Zr₀.₅₂Ti₀.₄₈)O₃ (PZT 52/48) ferroelectric ceramics was experimentally investigated. It was found that a dependence of breakdown field strength, Eg, of shocked ferroelectrics on the thickness of the element, d, ranging from 0.65 to 6.5 mm is described by the Eg (d) = γ  · d-w law that describes the breakdown of dielectrics at ambient conditions. It follows from the experimental results that the tunnel effect is a dominant mechanism of injection of prime electrons in the shocked ferroelectric elements. It was demonstrated that electric breakdown causes significant energy losses in miniature autonomous generators based on shock depolarization of poled ferroelectric elements

Electric Field-Free Gas Breakdown in Explosively Driven Generators

All known types of gas discharges require an electric field to initiate them. We are reporting on a unique type of gas breakdown in explosively driven generators that does not require an electric field

Compact Autonomous Explosive-Driven Pulsed Power System Based on a Capacitive Energy Storage Charged by a High-Voltage Shock-Wave Ferromagnetic Generator

A new concept for constructing compact autonomous pulsed power systems is presented. This concept utilizes a high-voltage explosive-driven shock-wave ferromagnetic generator (FMG) as a charging source for capacitive energy storage. It has been experimentally demonstrated that miniature FMGs (22-25 cm³ in size and 84-95 g in mass) developed for these experiments can be successfully used to charge capacitor banks. The FMGs, containing Nd₂Fe₁₄B energy-carrying elements, provided pulsed powers of 35-45 kW in times ranging from 10 to 15 µs. A methodology was developed for digital simulation of the operation of the transverse FMG. Experimental results that were obtained are in a good agreement with the results of digital simulations

Role of bone morphogenetic proteins in follicle development.

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