Nanotechnological Enhancement of Infrared Detectors by Plasmon Resonance in Transparent Conductive Oxide Nanoparticles

We investigated the use of plasmonic nanotechnology to enhance the performance of semiconductor infrared detectors. An increase of quantum efficiency, responsivity and specific detectivity is obtained by applying transparent conductive oxide (TCO) nanoparticles onto the surface of a photodetector. To this purpose we considered uncooled mercury cadmium telluride (HgCdTe) photoconductive detectors fabricated by isothermal vapor phase epitaxy, but the same procedure can be applied to cryogenically cooled devices, including those of photovoltaic type. The main mechanism of enhancement is light concentration ensured through localized plasmon resonance at the TCO nanoparticles and through enhanced scattering, while the desired wavelength range is reached by a further redshifting through the adjustment of nanoparticle properties. The improvement can be implemented during the final stages of production of the existing photovoltaic and photoconductive detectors. The method is applicable to various practical applications, including updating of high-precision guided ammunition

Discrete Deterministic Modelling of Autonomous Missiles Salvos

The paper deals with mathematical models of sequent salvos battle, of autonomous flight missiles (AFM) organized in the groups of combatants. Tactical integration of AFM system distance-controlled weapon is considered by performances of simultaneous approaches on targets, and continual battle models of guerilla and direct fire, are redesigned to the discrete-continual mixed model, for checking missiles sudden, and further salvos, attack effects. Superiority parameters, as well as losses and strengths of full, or the part of salvo battle, for the missiles groups as technology sub-systems combatants’, is expressed by mathematical and simulation examples. Targets engagements capacities of the missiles battle unit, is conducted through designed scenarios and mathematically derived in the research. Model orientated on answers about employment of rapid reaction defending tactics, by distance missiles attacks.Defence Science Journal, Vol. 64, No. 5, September 2014, pp.471-476, DOI:http://dx.doi.org/10.14429/dsj.64.579

Software/hardware design of decision-making controllers for object navigation in horizontal plane

Cilj rada je istražiti mogućnosti orijentacije objekta u horizontalnoj ravnini, počevši od njegovog početnog kursa u zahtjevani rakurs, koristeći pojednostavljene metode navigacije. Usmjeravanje gibanja objekta koristi kontrolirane pogonske impulse neravnomjerno distribuirane u ograničenom vremenskom intervalu gibanja. Dizajnirane su tri metode logičkog odlučivanja za izračunavanje najbolje putanje, čije su greške na cilju minimalne. Računanje pogonskih impulsa, njihovih izvršnih instanci kao i tipova, prezentirani su u ovom radu. Razvijene kontrolne mjere su: modificirana višestruka shooting metoda, odnosno novi zakon upravljanja kako je nazvan u ovom radu, trenutna orijentacijska greška, kao i metoda fuzzy logike. Metode su projektirane kao softver za donošenje odluke implementiran u elektronski hardver kao predefinirani programabilni kontroler. To daje preliminarno programiranje usmjeravanja objekta na samom početku kursa gibanja prema ciljnoj točki smještenoj van početnog pravca. Metodama se optimiziraju raspodijele ukupno determiniranog vremena radi realiziranja odgovarajućih tipova i broja pogonskih impulsa u sekvencama. Simulacijski testovi ovih metoda, kao i projektirani hardver, također su prezentirani u radu kao doprinos razvojnom istraživanju upravljanja horizontalnim gibanjem.The paper aims to research the orientation possibilities of an object in the horizontal plane, from its start course into a required orientating recourse, by using simplified navigation methods. The object’s directed motion uses controlling powering impulses, variable distributed in time, during constrained motion time. Three logical decision-making methods are designed for calculating the best maneuvering trajectory with minimal error on the target. Computing the powering impulses, their execution instances, as well as their types, are ensured by the methods and presented in the paper. The developed controlling methods are: a modified multiple shooting method, a new control law, called in this paper, current error orientation, as well as a fuzzy logic method. These methods are designed as decision-making software implemented in an electronic hardware as a predefined programmable controller. This provides pre-programmable orientation of the object at the very beginning of course motion, towards a targeted point settled out of initial direction. The controlling methods use optimal diversification of full elapsed determining time to execute, in sequences, appropriate types and number of powering impulses. Simulation tests of the methods, as well as the designed hardware, are also presented in this paper as a contribution to the development researches of horizontal motion control

Experimental and simulation testing of thermal loading in the jet tabs of a thrust vector control system

The paper discusses the temperature changes in mechanical jet tabs in a system of rocket motor thrust vector control, estimated by the simulation and experimental tests methodology. The heat transfer calculation is based on complex computational fluid dynamics simulations of both the nozzle and external tab flows, as the comprehensive integral flow zones with high flow parameters gradients. Due to a complexity of the model for flow calculations, the experimental estimation of the calculated results is carried out. The temperature is measured by jet tabs embedded thermocouples, and conducted through the rocket motor static tests. A good agreement of the calculated and measured results is achieved. The main aim of the developed method is to establish an approved calculation tool for designing new thurst vector control systems in order to avoid disadvantages due to overheating