Brodarski Institute

Several mixtures, based on urea, urea hydrogen peroxide complex (UHP), triacetone triperoxide (TATP) with some inorganic oxidants were studied by means of ballistics mortar with TNT as a reference standard. The detonation pressure, P, detonation velocity, D, detonation heat, Q, and volume of gaseous product at standard temperature and pressure conditions (STP condition) were calculated by the mean of Explo5 V6.3. The relatively high explosive strength of some samples relative to the TNT charge, focuses on the positive influence of hydrogen peroxide presence in these mixtures, with advantage in the form of its complex with urea (i.e. as UHP). This influence connects with hydroxi-radical in the mixture under its initiation (as the first intermediate of this initiation reaction).

Underwater noise has been measured and assessed in Croatia from the early seventies of the last century. Brodarski institute, in that time the technical institute of the ex Yugoslav Navy, has undertaken measurements of various vessel underwater noise as well as underwater ambient noise mainly on two specific locations of interest. Equipment was acquired, techniques and procedures developed and standardized and knowledge and expertise gathered. The measurements and assessment mainly of the vessel underwater noise were continued throughout the eighties. After two decades of virtual standstill, in the wake of requirements for underwater noise monitoring for Descriptor 11 of EU Marine Strategy Framework Directive (MSFD), a series of pilot underwater noise measurements were carried out. The measurement equipment, techniques and procedures as well as the outline of results are presented. The underwater ambient noise monitoring program for the next period has been established and defined and is also presented in the paper.

The Directive 2002/49 relating to the assessment and management of environmental noise and the Croatian legislative derived from it defines the basic rules to carry out strategic noise mapping. However, in real life situations, each mapping project implies a different approach, depending on various case related distinctions e.g. availability and quality of input data, extent of noise annoyance, the form and the volume of output data to be presented, etc. Based on the experience from various urban noise mapping projects, this work is an approach to defining key steps in urban noise map production and establishing standard step-by step procedure, and an attempt to define the procedure for each step. Examples for each step are given based on the case studies from our previous urban noise mapping projects.

Harmonic linearization, also known as describing function analysis is well known method for analysis of SISO systems. Computer aided harmonic linearization, as experimental practical method for determining static characteristics and describing functions is described. The use of linearly approximated static characteristic in determination of describing function introduces an inherent error resulting from the difference between original static characteristic and corresponding linearly approximated static characteristic. Error estimation and comparison of approximated characteristic error with the actual error is illustrated on several examples.

This paper focuses on design of instrumentation for non-destructive inspection of underground casing pipes, utilizing pulsed remote field technique. The presented inspection tool is designed for high-temperature environment operation, based on a principle of combining thermally `uprated' commercial-grade components with application-specific, high-temperature rated parts. Key design issues regarding the expected measurement performance and reliability of the tool are discussed. Results of laboratory tests have confirmed practical usability of the developed inspection tool for a targeted harsh-environment application.

The paper deals with analysis of turbine governor positioning system of hydroelectric power plant regarding nonlinear jump. The term resonance is used in the case of a sudden jump of amplitude and/or frequency and/or phase of a periodic output signal of a nonlinear system. Resonance jump cannot occur if excitation is such that the response of the system is transient and cannot be defined by solving nonlinear differential equations. Resonance jumps can cause severe damage and the mechanical, hydraulic and electrical systems with the saturation should be analyzed with the respect to the possibility of occurrence of jump. In the paper the analysis of the water turbine governor positioning system with the respect to the occurrence of jump is described. Two methods of analyzing system with the respect to jumps are described: the simulation method and the analytical method. When using the simulation method, the analysis of the variations of important parameters, including dead zone is performed and the simulation procedures are detailed. Then, the confirmation of the results of simulation is given by the analytical analysis method based on the describing function approach. At the end, the fuzzy regulator for avoidance of nonlinear jump in turbine governor positioning system is involved.

This paper presents a design of a simple, microcontroller-based interface for a frequency-output transducer, which is a part of a larger multichannel wired telemetry system. The function of the interface is to acquire frequency-modulated data from the transducer, prepare the data in the form suitable for transmission via logging cable, and handle the digital transmission protocol. A specific feature of the telemetry system is its operation in a high temperature environment (up to 180/spl deg/C), which requires high performance from the transducer interface circuit. The presented interface has been designed by combining the use of low-cost commercial components with 'clever' software techniques, as an alternative to the application of expensive high-temperature technologies. Preliminary results have shown that a reliable interfacing of transducers can be obtained, for high temperature, short-term data logging applications.

The detonation energies of several high explosives are evaluated from the results of chemical-equilibrium computer code named EXPLO5. Two methods of the evaluation of detonation energy are applied: (a) direct evaluation from the internal energy of detonation products at the CJ point and the energy of shock compression of the detonation products, i.e. by equating the detonation energy and the heat of detonation, and (b) evaluation from the expansion isentrope of detonation products, applying the JWL model. These energies are compared to the energies computed from cylinder test derived JWL coefficients. It is found out that the detonation energies obtained directly from the energy of detonation products at the CJ point are uniformly to high (0.9445±0.577 kJ/cm3), while the detonation energies evaluated from the expansion isentrope, are in a considerable agreement (0.2072±0.396 kJ/cm3) with the energies calculated from cylinder test derived JWL coefficients. Bewertung der Detonationsenergie aus Ergebnissen mit dem EXPLO5 Computer-Code Die Detonationsenergien verschiedener Hochleistungssprengstoffe werden bewertet aus den Ergebnissen des Computer Codes für chemische Gleichgewichte genannt EXPLO5. Zwei Methoden wurden angewendet: (a) direkte Bewertung aus der inneren Energie der Detonationsprodukte am CJ-Punkt und aus der Energie der Stoßkompression der Detonationsprodukte, d.h. durch Gleichsetzung von Detonationsenergie und Detonationswärme, (b) Auswertung durch die Expansions-Isentrope der Detonationsprodukte unter Anwendung des JWL-Modells. Diese Energien werden verglichen mit den berechneten Energien mit aus dem Zylindertest abgeleiteten JWL-Koeffizienten. Es wird gefunden, daß die Detonationsenergien, die direkt aus der Energie der Detonationsprodukte beim CJ-Punkt erhalten wurden, einheitlich zu hoch sind (0,9445±0,577 kJ/cm3), während die aus der Expansions-Isentrope erhaltenen in guter Übereinstimmung sind (0,2072±0,396 kJ/cm3) mit den berechneten Energien mit aus dem Zylindertest abgeleiteten JWL-Koeffizienten. Evaluation de l'energie de detonation à partir de résultats obtenus avec le code de calcul EXPLO5 Les energies de detonation de differents explosifs à haute puissance sont evaluees à partir des resultats obtenus avec le code de calcul des equilibres chimiques intitule EXPLO5. Deux methodes ont ete utilisees: (a) evaluation directe à partir de l'energie interne des produits de detonation au point CJ et à partir de l'énergie de la compression par choc des produits de detonation, c. à. d. par egalisation de l'energie de detonation et de la chaleur de detonation, (b) evaluation à partir des isentropes d'expansion des produits de detonation en utilisant le modèle JWL. Ces énergies sont comparees aux energies calculees à l'aide des coefficients JWL derives du test du cylindre. On a montre que les energies de detonation obtenues directement à partir de l'énergie des produits de détonation au point CJ sont uniformément trop elevees (0,9445±0,577 kJ/cm3), alors que celles obtenues à partir des isentropes d'expansion (0,2072±0,396 kJ/cm3) sont en bon accord avec les énergies calculées avec les coefficients JWL dérivés du test du cylindre.

The detonation energies of several high explosives are evaluated from the results of chemical-equilibrium computer code named EXPLO5. Two methods of the evaluation of detonation energy are applied: (a) direct evaluation from the internal energy of detonation products at the CJ point and the energy of shock compression of the detonation products, i.e. by equating the detonation energy and the heat of detonation, and (b) evaluation from the expansion isentrope of detonation products, applying the JWL model. These energies are compared to the energies computed from cylinder test derived JWL coefficients. It is found out that the detonation energies obtained directly from the energy of detonation products at the CJ point are uniformly to high (0.9445±0.577 kJ/cm3), while the detonation energies evaluated from the expansion isentrope, are in a considerable agreement (0.2072±0.396 kJ/cm3) with the energies calculated from cylinder test derived JWL coefficients. Bewertung der Detonationsenergie aus Ergebnissen mit dem EXPLO5 Computer-Code Die Detonationsenergien verschiedener Hochleistungssprengstoffe werden bewertet aus den Ergebnissen des Computer Codes für chemische Gleichgewichte genannt EXPLO5. Zwei Methoden wurden angewendet: (a) direkte Bewertung aus der inneren Energie der Detonationsprodukte am CJ-Punkt und aus der Energie der Stoßkompression der Detonationsprodukte, d.h. durch Gleichsetzung von Detonationsenergie und Detonationswärme, (b) Auswertung durch die Expansions-Isentrope der Detonationsprodukte unter Anwendung des JWL-Modells. Diese Energien werden verglichen mit den berechneten Energien mit aus dem Zylindertest abgeleiteten JWL-Koeffizienten. Es wird gefunden, daß die Detonationsenergien, die direkt aus der Energie der Detonationsprodukte beim CJ-Punkt erhalten wurden, einheitlich zu hoch sind (0,9445±0,577 kJ/cm3), während die aus der Expansions-Isentrope erhaltenen in guter Übereinstimmung sind (0,2072±0,396 kJ/cm3) mit den berechneten Energien mit aus dem Zylindertest abgeleiteten JWL-Koeffizienten. Evaluation de l'energie de detonation à partir de résultats obtenus avec le code de calcul EXPLO5 Les energies de detonation de differents explosifs à haute puissance sont evaluees à partir des resultats obtenus avec le code de calcul des equilibres chimiques intitule EXPLO5. Deux methodes ont ete utilisees: (a) evaluation directe à partir de l'energie interne des produits de detonation au point CJ et à partir de l'énergie de la compression par choc des produits de detonation, c. à. d. par egalisation de l'energie de detonation et de la chaleur de detonation, (b) evaluation à partir des isentropes d'expansion des produits de detonation en utilisant le modèle JWL. Ces énergies sont comparees aux energies calculees à l'aide des coefficients JWL derives du test du cylindre. On a montre que les energies de detonation obtenues directement à partir de l'énergie des produits de détonation au point CJ sont uniformément trop elevees (0,9445±0,577 kJ/cm3), alors que celles obtenues à partir des isentropes d'expansion (0,2072±0,396 kJ/cm3) sont en bon accord avec les énergies calculées avec les coefficients JWL dérivés du test du cylindre.