JŪROS DUGNO TYRIMO SONARU TOBULINIMAS

Examination of the seabed in the waterfront of the port and under the major sea–lanes is very important in the ever expanding port ofKlaipeda. Observations of the seabed with sonar equipment are useful for archaeologists, geologists and oceanologs in looking forsank ships and larger objects lost from ships, seabed pattern and its changing. Image quality obtained using side scan sonars arestrongly influenced by the sonar tow consistency. Even small sonar disturbances caused by mechanical disturbances can greatlyaffect the extracted sonar images quality. To eliminate this problem, mechatronic and software solutions suited for efficient work inever changing environment of Baltic Sea are being developed. Vessel motion measurement system have been designed. System successfullymade the experimental measurements and tested system prototype.KEY WORDS: the harbor bottom surveys, sonar, image processing

Analysis of installing ballast water treatment equipment on bulk carriers

In order to protect the world from the invasive species of organisms the cleaning ballast water is required, in other words, discharged water must meet requirements posted by the International Maritime Organization (IMO). The paper provides a comparative analysis of ballast water treatment equipment and its technical parameters. The research has been performed to analyse and assess the effect of the introduced equipment on ship stability, including the effect of its weight, dimensions, performance, price and the efficacy of choice. First published online 29 March 2016

Analysis into the selection of a ballast water treatment system

Today, it is very important to select and install the optimal equipment for the treatment of ballast water in existing ships. Increasing cargo volumes demand for a greater number of ships for transportation and expanded navigation geography as well as result in increased amount of discharged ballast water. Consequently, sea water pollution is increasing and invasive microorganisms appear that the existing flora and fauna are unaccustomed to. In order to protect territorial waters from these invasive species, International Maritime Organization (IMO) requirements have been implemented that regulate the quality parameters of discharged ballast water from ships. This problem has become particularly relevant for operational ships, in which ballast water treatment equipment and technical solutions had not been anticipated in the design stage. This article provides a comparative analysis of the treatment equipment of ballast water and the related technical parameters, in order to distinguish the most important equipment criteria. A Carrier, according to its technical characteristics, was analysed together with the water treatment method for operated bulk. An expert evaluation for the characteristics of the technical equipment was established

Investigation of the hydrodynamic processes of a centrifugal pump in a geothermal system

The hydrodynamic and thermodynamic processes of geothermal well extraction are investigated and presented in this paper. The paper presents mathematical models for a multi-level centrifugal pump and pipeline system. The mathematical models were used to evaluate gas (nitrogen) emission in water and its effects on hydrodynamic processes. Experimental studies and mathematical modelling showed that the gas content of the fluid increases the pressure and flow pulsations within a centrifugal pump. The variation in the height of the liquid column in extraction has an influence on characteristics of the multistage centrifugal pump used in wells. First published online 29 March 201

Dynamics of the processes in metal machining

In the practice of processing of metals by cutting it is necessary to overcome the vibration of the cutting tool, the processed detail and units of the machine tool. These vibrations in many cases are an obstacle to increase the productivity and quality of treatment of details on metal-cutting machine tools. Vibration at cutting of metals is a very diverse phenomenon due to both it’s nature and the form of oscillatory motion. The most general classification of vibrations at cutting is a division them into forced vibration and autovibrations. The most difficult to remove and poorly investigated are the autovibrations, i.e. vibrations arising at the absence of external periodic forces. The autovibrations, stipulated by the process of cutting on metalcutting machine are of two types: the low-frequency autovibrations and high-frequency autovibrations. When the low-frequency autovibration there appear, the cutting process ought to be terminated and the cause of the vibrations eliminated. Otherwise, there is a danger of a break of both machine and tool. In the case of high-frequency vibration the machine operates apparently quiently, but the processed surface feature small-sized roughness. The frequency of autovibrations can reach 5000 Hz and more

Modelling of chloride influence upon activated sludge community growth/Chloridų įtakos veikliojo dumblo biocenozės dinamikai modeliavimas/Моделирование влияния хлоридов на динамику биоценоза активного ила

Growth kinetics, i.e. the relationship between specific growth rate and the concentration of a substrate, is one of the basic tools in the modelling of activated sludge community growth. The above‐described conventional growth kinetics derived from single‐substrate‐controlled laboratory experiments have invariably been used for describing both growth and substrate utilization in wastewater treatment. After technological processes various mineral substances, such as chlorides, get into water bodies. These substances are not removed from wastewater by the biological treatment method. The purpose of this study is to determine the concentrations of chlorides, investigate the influence of enzyme preparations upon wastewater treatment quality during biological process modelling. Kinetics of microbial growth was designed using the model of Monad. To analyse the chloride influence on the biooxidation process a series of laboratory tests was carried out: biochemical oxygen consumption (BOD), activated sludge concentration and other indexes. It is found experimentally that a 400 mg/l concentration of chlorides disarranges the activity of microorganisms and activated sludge is no longer suitable for biological treatment. Also, we investigated the effect of enzyme preparation on effluence on sewage treatment. As chloride concentrations are increased in a tank without an enzyme, bacterial spores contained in the enzyme preparation produce a renewing effect upon active sludge. Santrauka Mikroorganizmų augimo dinamika, t. y. priklausomybė tarp jų savitojo augimo spartos ir substrato koncentracijos, yra vienas iš svarbiausių veiksnių modeliuojant veikliojo dumblo kinetiką. Laboratorinėmis sąlygomis buvo atlikti eksperimentiniai nuotekų valymo tyrimai kompleksiškai įdėjus į substratą ir chloridų kaip papildomos užtaršos bei fermentinio preparato. Rezultatams palyginti buvo atlikti tyrimai ir be fermentinio preparato. Po įvairių technologinių procesų į valymo įrenginius patenka tokios mineralinės medžiagos kaip chloridai. Šios medžiagos biologiniu valymo būdu iš nuotekų nepašalinamos. Darbe nagrinėjama, kokios chloridų koncentracijos turi įtakos biologinio nuotekų valymo kokybei, veikliojo dumblo augimo dinamikai bei substrato biodegradacijai. Eksperimentų metu nustatytos tiriamų teršalų koncentracijos, turėjusios įtakos biologiniam valymo procesui: 400 mg Cl– /l ir didesnės sutrikdo mikroorganizmų veiklą, veiklusis dumblas biologiniam nuotekų valymui tampa netinkamas. Darbe modeliuojama veikliojo dumblo mikroorganizmų biocenozės dinamika, atliekant aerobinį nuotekų valymą. Nagrinėtas atvejis, kai nuotekų užtarša yra didesnė chloridų koncentracija. Veikliojo dumblo biocenozės dinamikai modeliuoti pasirinktas Monodo modelis. Atlikus eksperimentą nustatyti degradacijos koeficientai kd. Gautas Monodo diferencialinės lygties sprendinys, nusakantis veikliojo dumblo dinamiką. Skaitiniais metodais išspręsta veikliojo dumblo augimą bei substrato biodegradaciją nusakanti diferencialinių lygčių sistema. Įvertinus eksperimentų rezultatus nustatyti veikliojo dumblo sistemos degradacijos koeficientai įdėjus fermentinio preparato. Rezultatai parodė, kad fermentinis preparatas teigiamai veikia mikroorganizmų augimą t. y. veikliojo dumblo koncentracija mažėja lėčiau. Резюме Кинетика биомассы микроорганизмов, т. е. зависимость между концентрацией активного ила и концентрацией субстрата, один из важнейших аспектов в моделировании динамики активного ила. В лабораторных условиях были проведены экспериментальные исследования сточных вод в комплексе с добавлением в субстрат хлоридов как дополнительного загрязнения и ферментного препарата. Для сравнения результатов были проведены параллельные эксперименты без ферментного препарата. В результате технологических процессов в очистные сооружения попадают разные минеральные вещества, как, например, хлориды. Эти вещества методом биологической очистки не удаляются. В настоящей работе были исследованы концентрации хлоридов, влияющие на качество биологической очистки сточных вод, качество и кинетику активного ила и биодеградацию субстрата. Для определения влияния хлоридов на биологические процессы были проведены лабораторные исследования по определению биохимического потребления кислорода (БПК), концентрации активного ила и др. В результате эксперимента было установлено, что концентрация хлоридов, составляющая 400 мг/л и больше, поражает работу микроорганизмов, активный ил становится непригодным для биологической очистки cточных вод. Также исследовалось влияние ферментного препарата на качество очистки. Моделируя кинетику динамики активного ила, получено решение дифференциального уравнения, в котором идентифицированы коэффициенты деградации ила kd. В результате эксперимента определены коэффициенты деградации на систему активного ила в резервуаре с ферментным препаратом, т. е. концентрация активного ила уменьшается медленнее. Можно сделать вывод, что ферментный препарат эффективно влияет на концентрацию микроорганизмов. First Published Online: 14 Oct 2010 Reikšminiai žodžiai: nuotekos, aerobinis valymas, veiklusis dumblas, chloridai, fermentai, matematinis modeliavimas. Ключевые слова: сточные воды, аэробная очистка, активный ил, хлориды, ферменты, математическое моделирование

The impact of the internal welding defects on the joint strength

The paper looks at the impact of the internal welding defects on the strength of joints. The tension tests provided the values of the welded joint strength limits depending on the area of sporadic voids, slag intrusions and the field of discontinuities. Considering the results of the conducted experiments, the mathematical relationships between the strength of the welded joint and defected area were concluded. In presence of all three defects, the distance of the defects from the weld surface was measured. It is deduced that the defects nearer to the surface reduce the strength of the welded joint more than those noticed in deeper layers. First published online: 27 Oct 201