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Nowadays, by expanding the application of thin layers in industry and medical sciences, their fabrication methods have also received attention. One of those methods is the vaporizing material method with the help of an electron gun. The most important part in the electron gun is the electron optic, which is responsible for producing and accelerating electrons, so that it becomes possible to vaporize refractory materials in a shorter period of time by better modifying and controlling the electron beam (the shape and diameter of the electron beam) at the target location. The reduction and control of the beam diameter in this evaporation source depends on various parameters such as device geometry, magnetic field intensity, electric power, etc. Therefore, in this research, the effect of those parameters was investigated by conducting experiments and using finite element and modeling software. The simulation results revealed that the effect of the effective parameters on the beam diameter can be predicted to a good extent, so that the diameter of the electron beam decreases by changing the geometrical shape, size and displacement of the output beam components. Then, the new electron gun, compared to the existing prototype, is optimized by applying these changes in the construction of the device and conducting experiments, and its beam diameter is reduced by 40% to be more focused.

Motile Aeromonads are responsible for various diseases in fishes that cause significant economic losses in aquaculture. Aeromonas spp. are also frequently isolated from fish suffering from Epizootic Ulcerative Syndrome (EUS). The present study was conducted to isolate and identify A. veronii from Vietnam climbing perch (Anabas testudineus) suffering from EUS, evaluate the pathogenicity of the isolates, and find out antibiogram profile and susceptibility of the isolates to medicinal plant extracts. Vietnam climbing perch (A. testudineus) suffering from EUS was collected from fish farms located at Savar, Dhaka and bacteria were isolated from the external ulcerative lesion, and kidney and liver of the infected fish on nutrient agar plates. Preliminary phenotypic identification of the bacterial isolates was performed following morphological, physiological and biochemical characterization tests. The 16S rRNA gene sequencing was accomplished for further molecular identification of five selected isolates. To evaluate the pathogenicity of the isolates in vivo artificial infection challenge test was conducted through immersion method. Another in vivo pathogenicity test was done at three different temperatures (18 °C, 28 °C, and 37 °C) to examine the effects of temperature on the pathogenicity of the isolates. Ten commercial antibiotics were used to find out the antibiogram profile of the isolates. Finally, susceptibility of the isolates was screened against 19 medicinal plants extracts. A total of 38 out of 46 isolates isolated from Vietnam climbing perch (A. testudineus) suffering from EUS were phenotypically identified as Aeromonas sp. Five randomly selected isolates were further confirmed as A. veronii by analyzing the 16S rRNA gene sequence homology. The pathogenicity of the isolates was found moderate to high (41%–80% mortality) in the artificially challenged fish. The highest and lowest mortality was obtained in the fish challenged with the isolates BFKA33 and BFKA12, respectively. The isolates were found resistant to several antibiotics, including amoxicillin, ampicillin, penicillin-G, and vancomycin. Nevertheless, extracts of three medicinal plant (Allium sativum, Syzygium aromaticum, and Tamarindus indica) demonstrated antibacterial activity to the isolates (BFKA12, BFKA15, BFKA18, BFKA29, and BFKA33).

One of the effective methods to reduce the kinetic energy downstream of hydraulic structures are the aprons. The horizontal aprons is one of these structures in the river that are often used downstream of stilling basins. At the time of execution, the apron and the riverbed are at the same level but when there is a flow in the boundary between the connection of the river bed and the aprons, scouring occurs, which causes the destruction of the apron and there is a possibility of destroying other water structures. In this research, using Flow 3D software, different scenarios were simulated for five Froude values of 0.32, 0.3, 0.25, 0.2, and 0.15, three Manning roughness coefficients of 0.025, 0.02, and 0.014 per particle diameter of 1.8 mm for horizontal aprons. In this numerical model, the graph of scouring depth changes in relation to Froude numbers in different roughness coefficients, the effect of Froude numbers on the location of the scour hole for different roughness coefficients of the horizontal aprons, the shear stress changes in relation to the length of the horizontal aprons with different roughness coefficients and different Froude numbers, as well as Erosion changes with respect to the length of the horizontal aprons were calculated with different roughness coefficients and different Froude numbers.

ABSTRACT Streptococcosis is one of the major threats to Nile tilapia (Oreochromis niloticus) in most regions of the world. Recently, Enterococcus faecalis has been widely reported to be involved in streptococcosis in O. niloticus in Asia and Africa. This study aimed to isolate beneficial marine bacteria to evaluate their effects on growth, hematological parameters, nonspecific immunity, the gut bacteriome, and streptococcosis prevention efficacy in O. niloticus. A total of 36 marine soil bacteria were isolated, and in vitro screening was conducted to determine their antibacterial activities against fish pathogens. Two antagonistic bacteria were identified based on 16S rRNA gene sequencing, Bacillus haynesii CD223 and Advenella mimigardefordensis SM421. These bacteria were incorporated into fish feed and fed to O. niloticus for 90 days. The application of these strains via incorporation into fish feed significantly promoted growth, improved hematological parameters and immunoglobulin M (IgM) levels, modulated the gut bacteriome by reducing the load of pathogenic Enterococcus spp., and developed disease prevention efficacy in O. niloticus. Furthermore, in vivo assays revealed that the inclusion of extracellular products (ECPs) (at 250 μg mL−1) of CD223 and SM421 with feed significantly enhanced the rate of survival (100%) of O. niloticus from streptococcosis compared to the controls (only 30%). The ECPs of these bacteria also prevented 90 to 100% of fish from developing streptococcosis. These strains could be promising for safe use in O. niloticus farming to prevent and control the emergence of streptococcosis caused by E. faecalis. IMPORTANCE Nile tilapia (Oreochromis niloticus) is one of the most economically important cultured fish species throughout the world. Streptococcosis is a significant threat to global Nile tilapia farming. Enterococcus faecalis has recently emerged as an important pathogen of streptococcosis in Asia and Africa. The application of antibiotics and probiotics and vaccination are the major ways to combat streptococcosis. However, the extensive use of antibiotics leads to the development of antibiotic resistance in pathogenic as well as environmental bacteria, which is a great threat to public health. There is no study on preventing streptococcosis caused by E. faecalis using beneficial bacteria. For the first time, the present study demonstrated that two marine bacteria, Bacillus haynesii strain CD223 and Advenella mimigardefordensis strain SM421, have great potential for controlling streptococcosis in Nile tilapia. These bacteria also enhanced the growth, improved hematological parameters and IgM levels, and positively modulated the gut bacteriome of Nile tilapia.

Coral geochemical tracers have been used in studies of the paleoclimatology and paleoceanography of the tropics and subtropics. We measured Sr/Ca and oxygen isotope ratios (δ18O) in a coral sample collected from the southern part of Lombok Strait, a significant outlet of the Indonesian Throughflow (ITF) to the Indian Ocean, to reconstruct the historical record of sea surface temperature (SST) and seawater δ18O. Seawater δ18O can be used to approximate sea surface salinity (SSS) because it reflects the balance of evaporation and precipitation. The resulting time series reconstructed SST and SSS, covering the period 1962–2012, shows no clear trend of global warming, although the record includes a large cooling event (~4°C) during 1996–1997. Although neither SST nor SSS shows a systematic relationship with El Niño–Southern Oscillation and Indian Ocean Dipole (IOD), weak but significant correlations are found partly. In addition, the coral data show signals of major IOD and El Niño events in 1994 and 1997, respectively, although climatic trends recorded in the coral are not consistent with those found along the Java-Sumatra coast. To evaluate other influences on the ITF in Lombok Strait, we compared our coral record with coral records from sites in the Java Sea, the southern part of Makassar Strait, and Ombai Strait. During the northwest monsoon (December–January–February), variations in SST and SSS at Lombok Strait site are similar to those at the Java Sea and southern Makassar sites for the period 1962–1995, which suggests that low-salinity water from the Java Sea is carried at least to the southern part of Makassar Strait where it suppresses the ITF upstream from Lombok Strait. However, the SST and SSS records differ at the three sites during the southeast monsoon (June–July–August), indicating that surface conditions in Lombok Strait vary separately from those in the Java Sea. In the longer term, although global warming has been widely identified in the Indonesian Seas, the coral record shows no clear warming trend in the southern part of Lombok Strait, where fluctuations in the ITF may be modulating the distribution of heat in the surface waters of the western Pacific and eastern Indian Ocean.

Introduction: Cavitation is one of the most important problems that may occur due to high flow velocity in dam spillways. In order to predict of dam spillway structure during operation, Azad dam spillway hydraulic model has been modeled in Tehran Water Research Institute. Materials and Methods:In this study, using computational fluid dynamics in the form of a finite volume method used in ANSYS FLUENT software, flow modeling in these channels, and a fluid volume model (VOF) in a three-dimensional state, including two-phase flow of water and air, used for Considering current turbulence, k-ε model has been used. In order to confirm the results of the model, a comparison was made with the results of a hydraulic model implemented without the aero-damping system of Azad spillway. Findings:Then, in order to confirm the location and number of aeration systems, two scenarios (two and three aeration systems) including step ramp (RAMP) on the floor and the wall of the duct with a suitable slope and the installation of the aeration slot in the wall have been used, which sends air near the floor And the walls will be. Conclusion:Then, by checking flow parameters such as speed, pressure and cavitation index, overflow with two aeration systems was confirmed as the best option.

In this study, alpha spectrometry and neutron activation analysis were applied to assess the mass accumulation rate, contamination history, and ecological risk of the Sundarban mangrove sediments. The mass accumulation rates of sediments using 210Pb dating determined for the first time in this area ranged from 0.068 to 3.20 kg m−2 y−1, with an average of 0.61 kg m−2 y−1. The contamination history of 11 metal(loid)s (Al, Ca, V, Cr, Fe, Ni, Cu, Zn, As, Hg, and Pb) was assessed. Different environmental contamination indices suggested that Sundarban mangrove sediments were contaminated by As. Considering different sediment quality guidelines, it was observed that Cr, Ni, and As posed occasional adverse biological effects on marine organisms. Multivariate statistical approaches were applied to elucidate the origin and transport behavior of the studied metal(loid)s in the mangrove ecosystem which suggested that sources of metal(loid) pollution were both anthropogenic and geogenic. The results from this study should improve the knowledge of metal contamination and ecological risk to biota to develop new strategies and enlarge management practices to save sensitive mangrove ecosystems. [ABSTRACT FROM AUTHOR]

Coral reef is a massive natural building block that mainly composed of hard coral. In ecological view coral reef is the center of biological activity for shelter, foraging and feeding place. Porites lutea is a common coral in reef flat area such as in Pantai Kondang Merak. This coral can form a massive with hillocky colony surface and has a slow linear extension rate, that made this coral has long longevity. The annual growth band of coral skeleton provide information of pollutants in the coastal extending back over several years ago due to ability of coral aragonite traped trace metal from environment. The aim of this research was to determine the concentration of trace metals of Cd, Cu and As along with the coral annual banding. The heavy metals detection was performed using ICP-OES (iCAP 7400 Series). The concentration of Cd, Cu and As in sample 1 (KM1) were 2.236 mg/kg, 9.726 mg/kg, and 2.474 mg/kg, while sample 2 (KM2) were 1.989 mg/kg, 19.157 mg/kg, and 2,064 mg/kg respectively. Two ways mechanism of trace metals to be trapped in the coral skeleton are by direct mechanism when trace metals in a form dissolved ion that were uptaken by coral then stored into coral skeleton and by indirect mechanism when particulate metals ingested by plankton then eaten by coral through coral tissue. The tracing of heavy metal in coral is provided important information of environment condition of the sea from 2009 - 2015 that may be used for authority decision regarding pollutant ambient in the sea environment.

Karimata strait connects South China Sea and Indonesia territorial seas where the strait current pattern is affected by west and east monsoon. This condition influences particles depositing sedimentation process in the strait. Lack information about sediment depositing rate at the straits dozens years ago makes this research is important to be conducted. This research was to estimate sediment depositing rate in the strait in two areas, near shore and off shore of Borneo. The research was conducted on June to September 2015 used coring sediment samples. Those samples were derived from Baruna Jaya VIII Ship Cruise on June 2015 that was collaborative research between Ministry of Marine and Fisheries Affairs of Indonesia and National Nuclear Center of Indonesia (BATAN).Samples were analyzed in the laboratory of Chemical and Ocean, Department of Environmental and Natural Resources, Center of Radiation and Isotope, National Nuclear Center of Indonesia (BATAN). Estimation of sediment depositing rate used natural isotope 210Pb. The study shows that the depositing rate of the nearest to Borneo area is about 0.92 kg.m-2.y-1 (1965) and increases to be 3.31 kg.m-2.y-1 (2009). The other area is about 0.08 kg.m-2.y-1 (1840) and increases to be 1.78 kg.m-2.y-1 (2010). This result implies that the sediment depositing rate at the nearest area to Borneo is higher than the off shore. Keywords: Near shore, off shore, Natural Isotop 210Pb, CRS (Constant Rate of Supply) model

The profile concentration of heavy metals, organic matter and the composition of the grain sizes is determined in two sediment cores from Karimata Strait. This study aimed to estimate the distribution of sediment grain sizes and distribution of heavy metals (Pb, Cu, Zn, Ni, As, and Fe) in three sediment fractions (>250 μm, 63-250 μm and

The skeleton of deposited coral species Porites lutea can provide information to determine the life growth rate of the coral that can be seen on its annual bands. The coral sampling was carried out by using pneumatic drill and then it was analyzed to determine the direction, age, and growth rates of the coral, using X-ray. Result of the research showed that the growth rate of P. lutea coral in northern station (windward) was in ranged of 0.6 – 2.5 cm/year while the average growth rate was 1.44 cm/year, and in the southern station (leeward) was in ranged of 0.5 – 2.2 cm/year while its average growth rate was 1.21 cm/year. The growth rate of P. lutea both located North station (Winward) and the South station (leeward) showed no significant difference.

Reliable prediction of boundary shear force distributions in open channel flow is crucial in many critical engineering problems such as channel design, calculation of energy losses and sedimentation. During floods, part of the discharge of a river is carried by the simple main channel and the rest is carried by the floodplains located to its sides. For such compound channels, the flow structure becomes complicated due to the transfer of momentum between the deep main channel and the adjoining floodplains that magnificently affects the shear stress distribution in floodplain and main channel sub sections. In the present study experiments were conducted in a compound rectangular section with different discharges and 3 different aspect ratios. The results showed that in each aspect ratio, shear stress increases by increasing the water level. It is also shown that by increasing the aspect ratio, shear stress is decreased significantly.