Production and biological characteristics and genotoxic status of clam <i>Corbicula japonica</i> (Bivalvia, Corbiculidae) in the estuary of Avvakumovka River (Olga Bay, northwestern Japan Sea)

In the mesohaline estuary of the Avvakumovka River (43°42’ N), the clam Corbicula japonica inhabits sand and silt-sandy grounds on the depths > 0.5 m in the main channel and tributaries from the mouth to 5 km upstream. The highest density (up to 175 ind./m2, 3882 g/m2) is observed in the mouths of tributaries with low velocity of the flow. Settlements in different parts of estuary differ by abundance of C. japonica , its size-age structure, and growth rates. The maximum observed shell size was 53 mm, the maximum weight of mollusk - 43 g, the maximum age - 13 years. The growth rate variability within the estuary is comparable with its latitudinal variation. The clam has the maximal linear increment of shell length in the first year of its life and the maximal weight increment - in the age of 5-7 years. It reaches the commercial size (shell length 20 mm) in 3-4 years old. The annual secondary production of C. japonica does not exceed 17.8 gС/m2, with P/B-ratio 0.37. Its annual consumption exceeds its biomass in 2.0-2.4 times. Corbicula japonica in the Avvakumovka River is practically unaffected by genotoxic influence; the estuary is defined as a clean, low-polluted area

Rogue waves and mode locking driven by Vector Resonance Multimode instability

Modulation instabilities discovered more than fifty and hundred fifty years ago created since then a framework for study complexity of different wave phenomena including turbulence and rogue waves. Using Erbium-doped fiber laser without any previously studied mode-locking mechanisms, here for the first time we demonstrate both experimentally and theoretically a new type of modulation instability, namely Vector Resonance Multimode Instability, leading to tunability of the laser dynamics from turbulence including rogue waves to the stable pulse train similar to the laser mode-locking regime

Temporal scaling of optical rogue waves in unidirectional ring fiber laser

A fiber mode-lock laser allows generation of the optical rogue wave (ORW) at different time scales. The criteria for distinguishing between them is a comparison of the event lifetime with the main characteristic time of the system. The characteristic time can be estimated from the decay of an autocorrelation function (AF). Thus, in comparison with AF characteristic time, fast optical rogue wave (FORW) events have duration less than the AF decay time and it appeared due to pulse-pulse interaction and nonlinear pulses dynamics. While slow optical rogue wave (SORW) have a duration much more longer than the decay time of the AF which it papered due to hopping between different attractors. Switching between regimes can be managed by change the artificial birefringence that induced in a laser cavity. For understanding the role playing by the periodical amplification and the resonator, we have performed an unidirectional fiber laser experiments without a saturable absorber. This laser experiment allowed to generate of most of the RW patterns which were either observed experimentally or predicted theoretically. In this way, we have observed the generation of an FORW along with SORW under similar conditions. Most of the patterns were found to be mutually exclusive which means that only one RW mechanism was realized in each regime of generation

Production of fish in the estuaries of Primorye

Production of fish communities is evaluated for 15 types of estuaries in Primorye on the data collected in 80 surveys (860 seine stations) conducted in 2002-2015. The bulk of the production in all cases is formed by semi-anadromous species ( Liza haematocheilus , Tribolodon spp., Hypomesus nipponensis and others). In polyhaline estuaries ( EP ), a significant part of the production is formed by resident marine species (mainly by Eleginus gracilis , Liopsetta pinnifasciata , Pholis nebulosa ) and southern migrants ( Mugil cephalus , Konosirus punctatus , Hyporhamphus sajori , Strongylura anastomella ). In mesohaline ( EM ) and oligohaline ( EO ) estuaries, the portions of marine residents and southern migrants are minimal, but the portion of freshwater species ( Gobio macrocephalus , Carassius gibelio , Phoxinus spp., Rhodeus sericeus , Acanthorhodeus spp., etc.) is heightened. Seasonal dynamics of the production is distinguished by the maximum in July-September. Mean fish biomass in May-October (vegetation season) varies in the range 143-1463 mgС/m2, mean annual production - from 174 to 4267 mgС/m2, and mean P/B -ratio - from 0.2 to 3.2. Previously (in 2007) much higher annual production was registered in the Artemovka River estuary - 9356 mgС/m2, but such high value was formed only once by juveniles of L. haematocheilus belonged to highly abundant year-class hatched in 2006. Both production and P/B are the lowest in the waterbodies with salinity close to the barrier values (5-8 ‰ for a - horohalinicum and 22-26 ‰ for b - horohalinicum) that is usual for the types EM and EP ; this lowering is caused by osmotic regulation for freshwater and marine fish, respectively, in particular their juveniles with low tolerance to salinity changes. That’s why EM estuaries have lower abundance of juveniles relative to adult fish and therefore the lower production. In general, patterns of fish production in the estuaries of Primorye are similar to production of well investigated estuaries in the moderate, subtropical and tropical zones. The values of fish production in the estuaries of Primorye are comparable with the production in mesotrophic and eutrophic lakes of north-western Russia; being significantly lower than the production in large floodplain rivers but higher than the production in small rivers. Fish production for seas, including Japan Sea (0.20 gС/m2) or its northwestern part - Peter the Great Bay (0.28 gС/m2), is significantly lower

Production of macrozoobenthos in the estuaries of Primorye

Secondary production of macrobenthic communities is evaluated for 14 different-type estuaries in Primorye on the base of 52 surveys conducted in 2007-2013 (922 stations, 2426 samples). Species composition and abundance of macrobenthos in the estuaries depend mostly on water salinity. Three types of estuaries were distinguished: i) polyhaline with prevaled salinity 18-30 ‰ (external and internal estuaries of the rivers Ryazanovka, Barabashevka, Sukhodol, Tumanovka and external estuaries of the rivers Olga and Avvakumovka); ii) mesohaline with salinity 5-18 ‰ (external and internal estuaries of the rivers Tesnaya and Gladkaya, internal estuaries of the rivers Avvakumovka, Kievka, and Partizanskaya, Lake Presnoye and external estuary of the Razdolnaya River); and iii) oligohaline with salinity 0.5-5.0 ‰ (internal estuaries of the rivers Razdolnaya, Artemovka and Lake Solenoye). Mean annual biomass of macrozoobenthos is the lowest (2.8 ± 0.4 gС/m2) in the polyhaline estuaries and the highest in the meso- and oligihaline ones (6.6 ± 3.0 and 7.0 ± 2.5 gС/m2, respectively). Annual production of macrobenthic communities in the estuaries varies from 0.5 to 11.2 gС/m2, with mean values 7.5 ± 1.0 gС/m2 in the polyhaline estuaries, 4.1 ± 1.3 gС/m2 in the mesohaline estuaries, and 2.7 ± 1.4 gС/m2 in the oligohaline estuaries, it is the highest in the polyhaline estuaries and the lowest in the oligohaline ones. The production is formed mainly by gastropods, bivalves, polychaetes and amphipods in the polyhaline estuaries; the same groups and also isopods and amphibiotic insects larvae form the production in the mesohaline estuaries, and bivalves and polychaetes are the main producers in the oligohaline estuaries. Daily production of macrobenthic community has strong seasonal variation with the maximum in July-September and the minimum (sometimes below zero) in May-June and October, i.e. at the beginning and the end of vegetation season. The portion of carnivore macrobenthos production varies from 0.7 to 26.5 % of the total annual production of macrobenthic community, it is the highest in the mesohaline estuaries. It increases from spring to autumn; in the autumn predators have the best feeding because of high abundance of young benthic animals at the bottom of estuaries. Mean annual P/B -ratio is 3.4, 1.1 and 0.4 for the polyhaline, mesohaline and oligohaline estuaries, respectively, that is conditioned by species composition of dominant taxonomic groups. Species composition of bivalve mollusks is the main factor of macrobenthic production variability: brackish clam Corbicula japonica with high biomass (up to 5 kg/m2) and low P/B -ratio (0.4-0.7, mean value ≈ 0.5) dominates in the mesohaline and oligohaline estuaries, while euryhaline marine bivalves as Macoma spp., Potamocorbula amurensis, Laternula marilina , and others dominate in the polyhaline estuaries though their biomass is relatively low (no more than 0.36 kg/m2), their P/B -ratio is 0.8-4.5. Year-to-year variability of macrozoobenthos production is supposedly significant, at least its considerable fluctuations are registered in the Sukhodol estuary (from 4.8 to 11.2 gС/m2 in the 2009-2012). Estuarine macrobenthic communities in Primorye usually have intermediate values of production between those in freshwater and seawater biotopes

Bright and dark vector rogue waves

For an Erbium-doped mode locked fibre laser, we demonstrate experimentally a new type of vector rogue waves (RWs) emergence of which is caused by the coherent coupling of the orthogonal states of polarisation (SOPs). Unlike weak interaction between neighbouring dissipative solitons for the soliton rain, this creates a new type of the energy landscape where the interaction of the orthogonal SOPs leads to polarisation trapping or escapes from the trapping triggered by polarisation instabilities and so results in the pulse dynamics satisfying criteria of the 'dark' and 'bright' RWs. The obtained results, apart from the fundamental interest, can provide a base for development of the rogue waves mitigation techniques in the context of the applications in photonics and beyond

Experiments on rehabilitation of radioactive metallic waste (RMW) of reactor stainless steels of Siberian chemical plant

Stainless steel pipes, used to cool a reactor plant, have a high cost, and aftertaking a reactor out of service they must be buried together with other radioactivewaste. Therefore, the relevant problem is the rinse of pipes from contamination,followed by returning to operation

Composition, distribution, and seasonal dynamics of vegetation in the estuaries of the Olga Bay (central Primorye)

Twenty-one species of water plants are found in the Avvakumovka River estuary and fourteen species - in the Olga River estuary in 3 surveys conducted in May, July, and September of 2012. Zostera marina dominates in the external estuary of both rivers in any season, whereas Potamogeton spp. and Ruppia maritima are the most abundant in some local areas of the Avvakumovka external estuary and Zostera japonica - in some local shallow areas of the Olga external estuary (where it forms perennial settlements). Chaetomorpha linum is the subdominant species in the Olga external estuary. In the Avvakumovka internal estuary, Cladophora glomerata and Z. marina are the dominants in May, Z. marina - in July, and Z. marina and Potamogeton spp. - in September, but any bottom vegetation is absent in the Olga internal estuary. From May to September of 2012, the summary biomass of water vegetation in both estuaries increased in 5 times: from 0.3 to 1.5 thousand tons

Bright-dark rogue wave in mode-locked fibre laser

Rogue waves (RWs) are statistically rare localized waves with high amplitude that suddenly appear and disappear in oceans, water tanks, and optical systems [1]. The investigation of these events in optics, optical rogue waves, is of interest for both fundamental research and applied science. Recently, we have shown that the adjustment of the incavity birefringence and pump polarization leads to emerge optical RW events [2-4]. Here, we report the first experimental observation of vector bright-dark RWs in an erbium–doped stretched pulse mode-locked fiber laser. The change of induced in-cavity birefringence provides an opportunity to observe RW events at pump power is a little higher than the lasing threshold. Polarization instabilities in the laser cavity result in the coupling between two orthogonal linearly polarized components leading to the emergence of bright-dark RWs. The observed clusters belongs to the class of slow optical RWs because their lifetime is of order of a thousand of laser cavity roundtrip periods

Анализ состояния вопроса утилизации низкопотенциальных энергетических ресурсов на объектах малой энергетики

Studying the issues of recovery of low-potential energy at smallscale energy facilities allowed to show the promising character of the organic Rankine cycle (ORC) technology as a technology for recovery or conversion of low-potential energy.The most promising developments in the field of the use and recovery of waste heat are described regarding application of ORC, which is widely used in geothermal sources, hot water boilers, gas turbine plants. Due to the constantly growing diversity of working fluids, ORC can be used within a wide temperature range from 100°C to over 350°C. Also, developments are underway in the design of ORC generators to increase reliability of its individual system units, such as turbines and expanders. Based on the above factors, it can be concluded that with a deeper study of the problems of adopting ORC technologies, they can become a very promising direction in development of heat power engineering.It has been determined that the main factor hindering the widespread adoption of the ORC technology is associated with high cost of heat exchange equipment due to increased heat exchange surfaces. It is shown that design of mini power plants and energy centres based on the use of low-potential energy requires improvement of mathematical modelling methods to reliably determine operating modes and characteristics of each of the units. Methods for modelling evaporation and condensation systems, including turbines and expanders using organic low-boiling working fluids, should be considered among the methods that are highly sought after. The methods for selecting a working fluid for ORC devices also have a significant impact on characteristics of the installation determining the range of cycle operating temperatures and pressures. The solution of the above problems can lead to a reduction in the cost of heat exchange equipment, and, consequently, to a decrease in costs for design of ORC generators. В статье рассмотрены вопросы утилизации низкопотенциальных энергетических ресурсов на объектах малой энергетики. Показана перспектива использования технологии органического цикла Ренкина (ОЦР) в качестве технологии утилизации или преобразования низкопотенциальной энергии.Приведены разработки в области реализации и утилизации бросового тепла. Наиболее перспективные из них представлены в применении ОЦР, который широко используется на геотермальных источниках, в водогрейных котельных, газотурбинных установках. За счёт постоянного растущего сортамента рабочих тел ОЦР может применяться в широком температурном диапазоне, начиная от 100°С и заканчивая свыше 350°С. Также ведутся разработки в области проектирования ОЦР-генераторов с целью повышения надёжности отдельных узлов системы, таких как турбины и детандеры. Исходя из вышеперечисленных факторов, можно сделать вывод, что при более глубоком исследовании проблем внедрения ОЦР-технологий они могут стать весьма перспективным направлением в развитии теплоэнергетики.Определено, что основным фактором, препятствующим широкому внедрению ОЦР-технологии, является высокая стоимость теплообменного оборудования из-за повышенных теплообменных поверхностей. Показано, что проектирование миниэлектростанций и энергокомплексов на основе использования низкопотенциальной энергии требует совершенствования методов математического моделирования для достоверного определения режимов работы и характеристик каждого из агрегатов. К востребованным следует отнести методы моделирования испарительных и конденсационных систем, в том числе турбин и детандеров, работающих на органических низкокипящих рабочих телах. Методики выбора рабочего тела для ОЦР-устройств также оказывают существенное влияние на характеристики установки, которые определяют диапазон эксплуатационных температур и давлений цикла. Решение вышеуказанных задач способно привести к удешевлению теплообменного оборудования, а, следовательно, снижению издержек на проектирование ОЦР-генераторов.