bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct writing of lateral fluorographene nanopatterns with tunable bandgaps and its application in new generation of moiré superlattice
Authors: Li Hu , Duan Tianbo , Haldar Soumyajyoti , Sanyal Biplab , Eriksson Olle , Jafri Hassan , Hajjar-Garreau Samar , Simon Laurent , Leifer Klaus
Published: January 2020

One of the primary goals for monolayer device fabrications and an ideal model of graphene as an atomic thin “canvas” is one that permits semiconducting/insulating lateral nanopatterns to be freely and directly drawn on the semimetallic graphene surface. This work demonstrates a reversible electron-beam-activated technique that allows direct writing of semiconducting/insulating fluorographene lateral nanopatterns with tunable bandgaps on the graphene surface with a resolution down to 9–15 nm. This approach overcomes the conventional limit of semiconducting C4F in the single-sided fluorination of supported graphene and achieves insulating C2F. Moreover, applying this technique on bilayer graphene demonstrates for the first time a new type of rectangular moiré pattern arising from the generated C2F boat/graphene superlattice. This novel technique constitutes a new approach to fabricating graphene-based flexible and transparent electronic nanodevices with the CxF channels utilized as semiconducting or insulating counterparts, and also opens a route toward the tailoring and engineering of electronic properties of such materials in addition to the dominating triangular moiré patterns from a graphene/hBN system.
Magnetic characteristics of a magnetic marker for localized tumor excision with a handheld magnetic probe
Authors: Xiao Yingyi , Debnath Oiendrila Bhowmik , Chikaki Shinichi , Kuwahata Akihiro , Peek Mirjam , Saito Itsuro , Maeda Shinsaku , Kusakabe Moriaki , Sekino Masaki
Published: January 2020

To excise the non-palpable breast lesion, conventionally surgeons estimate the excision margin by naked eyes subjectively with a localization tool such as a hook wire. By introducing a magnetic detection system, location of the magnetic marker injected intratumorally can be identified with a handheld magnetic probe. Detection ranges of existing magnetic markers are up to 30 mm, limiting applications on tumors located deeper down the skin. In this study, materials and designs of magnetic markers are evaluated to achieve an extended detection range. Stainless steel (SUS) 304 is magnetic and biocompatible for an implant device, and a SQUID measurement is performed to evaluate its magnetic properties. A numerical simulation tool has been developed to evaluate the magnetic field strength induced by the magnetic marker from any orientation. Based on a backward-facing hook shape design, magnetic field strength induced by the marker with varies hook length and separation angle between the hook and the main body is evaluated. At an extended distance of 40 mm, the detection of the magnetic marker with 8 mm hook length and 75° separation angle can be achieved on 57% of the orientations.
The effect of surface roughness on the phase behavior of colloidal particles
Authors: Moinuddin Md , Biswas Prithwish , Tripathy Mukta
Published: January 2020

Shape anisotropy of colloidal particles can give rise to complex intermolecular interactions that determine particle packing and phase behavior. The vapor–liquid coexistence curves of attractive rough particles display a shift when compared to attractive smooth spherical particles. We use Integral Equation Theory (IET) to determine the vapor–liquid spinodal phase diagram of smooth and rough colloidal particles interacting through square-well attraction. Additionally, we use Gibbs Ensemble Monte Carlo (GEMC) simulations to locate their vapor–liquid coexistence curves. We model a rough colloidal particle as a spherical core with small beads embedded on its surface. The critical point of smooth spherical particle systems predicted by theory and simulations is in quantitative agreement. An increase in surface roughness due to an increase in either the number of beads or the diameter of the beads has a modest effect on the local structure of the system in the supercritical region. In contrast, increasing surface roughness consistently shifts the vapor–liquid coexistence curves to higher temperatures. The critical temperature is found to be a quadratic function of the number of beads. At a fixed bead size and number of beads, the critical temperature does not vary with the arrangement of beads on the core. Both IET and GEMC simulations predict that unlike critical temperatures, critical packing fractions vary non-monotonically with surface roughness. We find that the feasibility and accuracy of the integral equation theory depend sensitively on the chosen closure combination.
Improving photoresponsivity in GaAs film grown on Al-induced-crystallized Ge on an insulator
Authors: Nishida T. , Suemasu T. , Toko K.
Published: January 2020

The highest recorded photoresponsivity in polycrystalline GaAs films on glass has been updated by precisely controlling the growth temperature of GaAs on a Ge seed layer formed by Al-induced layer exchange. X-ray diffraction and electron backscatter diffraction analyses showed that large-grained (>100 µm) GaAs (111) films epitaxially grew from the Ge layer above 510 °C. According to energy dispersive x-ray and Raman spectra, 550 °C was the optimum growth temperature that allowed for the growth of high-quality GaAs film with a stoichiometric composition. Reflecting the high crystallinity, the internal quantum efficiency reached 90% under a bias voltage of 0.3 V. Low-temperature GaAs films grown on inexpensive substrates will make the development of advanced solar cells that achieve both high efficiency and low cost possible.
Synthesis of twin-structured nanodiamond particles
Authors: Ying Pan , Gao Yufei , Zhang Bin , Wu Yingju , Li Zihe , Gao Guoying , Xu Bo , Yu Dongli , Hu Wentao , Zhao Zhisheng , He Julong , Tian Yongjun
Published: January 2020

Nanodiamonds represent a burgeoning class of carbon nanomaterials that possess favorable physical and chemical properties useful in abrasives, chemocatalysis, biomedicine, etc. Nowadays, the research on nanodiamonds has developed rapidly, with impressive control over particle size and morphology. However, the synthesis of nanodiamonds with ubiquitous nanotwinned substructure has yet to be realized. Here, we report the synthesis of nanotwin-structured nanodiamond particles from onion carbon precursors (with potassium chloride working as the isolation layer) under high pressure and high temperature conditions. The structural characterizations indicate that the synthetic nanodiamonds contain a nanotwinned substructure within individual particles, with an average twin thickness of ∼5 nm. The current work demonstrates an effective approach to nanodiamond particles with a nanotwinned substructure, which may promote applications in related areas.
RNA sequencing by direct tagmentation of RNA/DNA hybrids
Authors: Di Lin , Fu Yusi , Sun Yue , Li Jie , Liu Lu , Yao Jiacheng , Wang Guanbo , Wu Yalei , Lao Kaiqin , Lee Raymond W. , Zheng Genhua , Xu Jun , Oh Juntaek , Wang Dong , Xie X. Sunney , Huang Yanyi , Wang Jianbin
Published: January 2020

Transcriptome profiling by RNA sequencing (RNA-seq) has been widely used to characterize cellular status, but it relies on second-strand complementary DNA (cDNA) synthesis to generate initial material for library preparation. Here we use bacterial transposase Tn5, which has been increasingly used in various high-throughput DNA analyses, to construct RNA-seq libraries without second-strand synthesis. We show that Tn5 transposome can randomly bind RNA/DNA heteroduplexes and add sequencing adapters onto RNA directly after reverse transcription. This method, Sequencing HEteRo RNA-DNA-hYbrid (SHERRY), is versatile and scalable. SHERRY accepts a wide range of starting materials, from bulk RNA to single cells. SHERRY offers a greatly simplified protocol and produces results with higher reproducibility and GC uniformity compared with prevailing RNA-seq methods.
Collisionless electron cooling in a plasma thruster plume: experimental validation of a kinetic model
Authors: Merino Mario , Fajardo Pablo , Giono Gabriel , Ivchenko Nickolay , Gudmundsson Jón-Tómas , Mazouffre Stéphane , Loubère Dimitry , Dannenmayer Käthe
Published: January 2020

A central challenge in the modeling of the near-collisionless expansion of a plasma thruster plume into vacuum is the inadequacy of traditional fluid closure relations for the electron species, such as isothermal or adiabatic laws, because the electron response in the plume is essentially kinetic and global. This work presents the validation of the kinetic plasma plume model presented in (Merino et al 2018 Plasma Sources Sci. Technol.
27 035013) against the experimental plume measurements of a SPT-100-ML Hall thruster running on xenon presented in (Giono et al 2018 Plasma Sources Sci. Technol.
27 015006). The model predictions are compared against the experimentally-determined axial profiles of electric potential, electron density, and electron temperature, and the radial electric potential profile, for 6 different test cases, in the far expansion region between 0.5 and 1.5 m away from the thruster exit. The model shows good agreement with the experimental data and the error is within the experimental uncertainty. The extrapolation of the model to the thruster exit plane and far downstream is consistent with the expected trends with varying discharge voltage and mass flow rate. The lumped-model value of the polytropic cooling exponent γ is similar for all test cases and varies in the range 1.26–1.31.
Experimental study of the elastic scattering of 10Be on 208Pb at the energy of around three times the Coulomb barrier *
Authors: Duan Fang-Fang , Yang Yan-Yun , Pang Dan-Yang , Hu Bi-Tao , Wang Jian-Song , Wang Kang , Yang Guo , Guimarães Valdir , Ma Peng , Xu Shi-Wei , Liu Xing-Quan , Ma Jun-Bing , Bai Zhen , Hu Qiang , Jin Shu-Ya , Sun Xin-Xin , Yao Jia-Sheng , Qi Hang-Kai , Sun Zhi-Yu
Published: January 2020

Elastic scattering of 10Be on a 208Pb target was measured at

= 127 MeV, which corresponds to three times the Coulomb barrier. The secondary 10Be beam was produced at the Radioactive Ion Beam Line in Lanzhou of the Heavy-Ion Research Facility in Lanzhou. The angular distribution of elastic scattering in the 10Be + 208Pb system shows a typical Fresnel diffraction peak. Optical model analysis of the angular distribution was performed using the Woods-Saxon, double-folding and global potentials. With the global potential, different density distributions were used. The results indicate that different density distributions for the projectile induce distinct effects in the angular distribution.
Multi-quasiparticle excitations of 91Ru *
Authors: Zheng Yong , France G. de , Zhou Xiao-Hong , Huang Shan , Liu Min-Liang
Published: January 2020

The level structure in neutron-deficient nucleus 91Ru was investigated via the 58Ni (36Ar, 2p1n

) 91Ru reaction at a beam energy of 111 MeV. Charged particles, neutrons, and

-rays were emitted in this reaction and detected by the DIAMANT CsI ball, Neutron Wall, and the EXOGAM Ge clover array, respectively. In addition to the previously reported levels in 91Ru, new low-to-medium spin states were observed. Angular correlation and linear polarization measurements were performed to unambiguously determine spins and parities of the excited states in 91Ru. The low-spin states of 91Ru exhibit a scheme of multi-quasiparticle excitations, which is very similar to that of the neighboring

isotone. These excitations have been interpreted in terms of the shell model. The calculations performed in the configuration space

reproduce the experimental excitation energies reasonably well, supporting the interpretation of the newly assigned positive-parity states in terms of the three quasiparticle configurations

and

.
A systematical study of the chiral magnetic effects at the RHIC and LHC energies *
Authors: Chen Bang-Xiang , Feng Sheng-Qin
Published: January 2020

Considering the magnetic field response of the QGP medium, we perform a systematical study of the chiral magnetic effect (CME), and make a comparison with the experimental results for the background-subtracted correlator H at the energies of the RHIC Beam Energy Scan (BES) and the LHC energy. The CME signals from our computations show a centrality trend and beam energy dependence that are qualitatively consistent with the experimental measurements of the charge dependent correlations. The time evolution of the chiral electromagnetic current at the RHIC and LHC energies is systematically studied. The dependence of the time-integrated current signal on the beam energy

with different centralities is investigated. Our phenomenological analysis shows that the time-integrated electromagnetic current is maximal near the collision energy

GeV . The qualitative trend of the induced electromagnetic current is in agreement with the CME experimental results at the RHIC and LHC energies.
The Δ mass dependence of the Mmatrix and its influence on the

cross-sections *
Authors: Cui Ying , Zhang Ying-Xun , Li Zhu-Xia
Published: January 2020

The

mass dependence of the Mmatrix and its influence on the

cross-sections are investigated in the one-boson exchange model. Our calculations show that the

mass dependence of the momentum of the outgoing

and the M matrix affects the calculations of

, especially around the threshold energy.
Weak deflection angle of extended uncertainty principle black holes *
Authors: Kumaran Yashmitha , Övgün Ali
Published: January 2020

We discuss the effects of quantum fluctuations spewed by a black hole on its deflection angle. The Gauss-Bonnet theorem (GBT) is exploited with quantum corrections through the extended uncertainty principle (EUP), and the corresponding deflection angle is obtained. Moreover, we have attempted to broaden the scope of our work by subsuming the effects of plasma medium on the deflection angle. To demonstrate the degree of difference, the acquired results are compared with the prevailing findings.
Effect of Fe doping on the electrical properties of BaTiO3 crystalline materials at room temperature
Authors: Triyono D , Betria B , Laysandra H
Published: January 2020

In this study, we report the room temperature electrical properties of BaFexTi1-x O3 (x = 0.4, 0.5, and 0.6) crystalline materials. The materials were synthesized via a solid-state reaction. The structural properties were investigated via X-ray diffraction, showing a hexagonal perovskite structure with the P63/m space group. The room temperature electrical properties were characterized using impedance spectroscopy. The impedance data indicate a decreasing of ferroelectric behavior and the appearance of ferromagnetic behavior. The frequency spectra of the impedance show the presence of electrical relaxation in the materials, the extent of which depends on the Fe content. Doping BaTiO3 with Fe reduces the relaxation time in the system.
Analysis of optical and structural properties of Ti-doped ZnO nanoparticles synthesized by co-precipitation method
Authors: Darmadi I , Taufik A , Saleh R
Published: January 2020

In this study, we used the co-precipitation method to synthesize Ti-doped ZnO nanoparticles having different Ti contents. We then used energy dispersive X-ray spectroscopy to perform an elemental analysis, which revealed that the Ti content varied in its atomic percentages from 5 at.%, 7 at.%, and 12 at.% to 16 at.%. We characterized the structural properties of the prepared samples using X-ray diffraction (XRD) spectroscopy and found Ti-doped ZnO to have an anatase structure in which the lattice parameters a = b and c decrease from 3.251 and 5.213 Å to 3.254 and 5.203 Å, respectively, when the Ti content increased from 5 at.% to 16 at.%. We also found the grain size of Fe-doped TiO2 to decrease from 12 nm to 10 nm with increasing Ti content. We characterized the molecular vibration of the samples using Fourier transform-infrared spectroscopy (FT-IR) and the optical properties using UV-Vis diffuse reflectance spectroscopy. The results show the band-gap energy of Ti-doped ZnO to decrease from 3.20 eV to 3.12 eV. We tested the photocatalytic activity of Ti-doped ZnO in the degradation of methylene blue from the aqueous solution under UV light irradiation and found the photocatalyst Ti-doped ZnO to have good degradation ability, with a degradation percentage of approximately 80 %.
Relationships pattern of social media addiction level to morality level, apathetic level and academic score
Authors: Ralasari I , Setiadi R , Soemartojo S M
Published: January 2020

Social media addiction is a situation where student uses social media until they do not have time or willingness to do anything else. Social media addictions have already influenced teenagers in many countries including the students at XYZ high school. Social media addiction can affect morality level of the students because of the contents appeared in the social media. They can be influenced by the chatting, pictures and others things when they use social media. The value in the social media is not always good. Sometimes it contains violence, infidelity, drugs, pornography etc. These things are dangerous for the morality of the students. Other than that, social media addiction causes student’s apathetic level will be increased. Students are very interested to chat in social media and do not care of others. Beside it, the students tend to have low academic score because they use their time more to use media social. All of these are very dangerous to the future of the students. Because of these reasons, the writer wants to know the pattern of relationship between social media addiction and morality level, apathetic level and academic score. These variables are latent variables so the data analysis will use partial least square method to solve the problem. The findings of the data analyses show that social media addiction level affect academic score and apathetic level of students in XYZ high school and the morality level affects students’ academic score in XYZ high school.
Modeling the relationship of factors that shaped student’s loyalty
Authors: Haqka E F , Setiadi R , Siswantining T
Published: January 2020

Student’s loyalty is the intention and behaviour of students that shows devotion to the institution by contributing to expand it. Having loyal students can increase the reputation and number of applicants because loyal students promote the institution from mouth to mouth. Even when they have graduated, they would still support their institution financially or in the form of collaborations. These contribute to the long-term development and the longevity of the institution. This study is made to find out about the factors that influence the level of student’s loyalty. 233 samples are gathered using complex sampling. Students in their second to third year are chosen, then they are stratified by department and random sampling is done under each stratum. From the result that uses the method Partial least square (PLS) path modelling, it shows factors that influence student’s loyalty respectively from the ones with the greatest influence are student’s satisfaction, student’s affective commitment, social environment quality, image and reputation perception, student’s perceived value, student’s trust, social integration, instructor quality, and administration quality.
Claim reserve prediction using the credibility theory for the Chain Ladder method
Authors: Karmila S , Nurrohmah S , Sari S F
Published: January 2020

A claim reserve is a reserve that must be prepared by a long-tail business insurance company to fulfil its obligations to future policyholders. One of the most popular methods for predicting claim reserves is the Chain Ladder method. However, on the Chain Ladder method, the claim reserve is predicted solely based on individual information (information derived from the company’s past experienced). If the individual information is not enough, an actuary needs to consider other information that is collective information (market experience). Both information can be combined by applying Bühlmann-Straub credibility theory. This paper will discuss about implementation of credibility theory for the Chain Ladder method to predict claim reserve for the data of private passenger autoliability/medical insurance in 1998-2007 are published by National Association of Insurance Commissioners (NAIC).
Intrusion detection system model using Fuzzy Kernel C-Means and Laplacian Score feature selection
Authors: Rustam Z , Maharani J
Published: January 2020

Nowadays, where the technology dominates every field and activity like transaction, learning activities, private or corporate data storage, and so on are things that we have to look in detail especially in terms of security both in data storage and technology utilization. The trust of the security itself can be represented by the accuracy on model we used but the question is “Which model is good for the security?”, that question can be answered by the research or trial of models either by combining the models or construct the new one. Therefore, in this paper we tried an intrusion detection system model by combining Fuzzy Kernel C-Means method as a classifier and Laplacian Score method as a feature selection applied on KDD Cup 99 Data Set. As a result, we will see the comparison of the accuracy of intrusion detection system (IDS) model using Fuzzy Kernel C-means with and without Laplacian Score Feature Selection for the same data and features that resulted 60% and 67.06%, respectively.
The utilization status of Yellowfin Tuna (Thunnus albacares) in Morotai Island Regency
Authors: Talahatu M F , Susiloningtyas D , Budiharsono S , Handayani T
Published: January 2020

Morotai Island Regency is located in the adjacent of three National Fisheries Management Area of Indonesian Republic (WPPNRI 715, WPPNRI 716, WPPNRI 717). Geographically Morotai Island’s waters lie in two Indonesian hydro-oceanography phenomenon, namely Throughflow and Eddy Halmahera which affect the abundance of marine resources. This study aims to determine the utilization status of Yellowfin Tuna (Thunnus albacares) in Morotai Island regency including: catch per unit effort (CPUE), maximum sustainable yield (MSY), total allowed catch (TAC) and Utilization rate. Within a period of ten years (2009-2018) Yellowfin productivity was fluctuating with a CPUE of 4.1 kg/trip. Fox surplus production model calculation showed that MSY of yellowfin resource was amounted of 8,657,679 kg/year with a maximum effort value of 42,429 trips/year. The number of TAC value was amounted of 6,926,143 with a utilization level of 12.23%. Yellowfin utilization level was amounted of less than 33.3% which is relatively low. This shows that Yellowfin Tuna stock in Morotai Island regency has not been optimally utilized.
Numerical modeling of abrasion hazard in Senindara River, Bintuni Bay
Authors: Hernawan U , Prasetio F B , Risdianto R K
Published: January 2020

The Senindara River area, which is part of Bintuni Bay, was influenced by the dynamics of the seawater and widely used to support community and industries activities. Alluvium land conditions and partially cliff were potential to abrasion. The research location was Senindara River with focused in Maga River area. This study aims was to obtain potential abrasion hazard of the study area. Numerical modelling was used to analysed the data. Tidal observations were carried out for 15 days with peilschaal and processed using Admiralty method. Current measurements were conducted for 26 hours using the Eulerian method. Modeling using MIKE21 FM Model with momentum, temperature, and density equations. Spatial discretion of the equation was done using the cell-centered finite volume method. Model calibration was done by comparing the output of the model (current and water level) with the observation results. The study shows the value of the basic shear stress of the average model value was greater than the value of the basic shear stress critical model erosion 0.1 N/m2. This shows that at the observation location has a high risk abrasion, especially in the industrial supporting area. Therefore, prevention of abrasion hazards was indispensable.
Rainfall analysis in the Indian Ocean by using 6-States Markov Chain Model
Authors: Miftahuddin  , Maulidawani  , Setiawan I , Ilhamsyah Y , Fadhli
Published: January 2020

In this study, we used Markov chain approach to analyze rainfall dataset from one buoy (4N90E) in the eastern Equatorial Indian Ocean. This study aims to determine the opportunity for transition (displacement) of daily rainfall intensity, where there are six states or conditions of rainfall intensity, i.e. no rain, very weak, weak rain, moderate rain, heavy rain, and very heavy rain. The Markov Chain method used is the Chapman-Kolmogorov equation and the steady state equation. The investigation of the 6-states in Markov chain model show that dynamic probability of transition state for rainfall data is reflexive properties majority. By using the model, it is concluded that the transition rate matrix of the largest transition probability in the area of 4N90E occurs at the transition from state-1 to state-1 as much is 0.72 and state-2 to state-2 is 0.60. The transition probability value becomes 0.5184 and 0.36 for the same state dominant of two periods P
2. The use of the 1st order Markov chain is better than 2nd order.
Study of water discharge in the Ulee Lheue Port Channel, Indonesia
Authors: Setiawan I , Isbah F , Muhammad M , Yuni S M , Purnawan S , Akram A , Ilhamsyah Y
Published: January 2020

Ulee Lheue serve as ferry ports in Banda Aceh, covering an area of ±8 ha. The information on water flow entering the port channel is needed to determine the quantity of water and facilitating transportation at the port. This study includes the measurement of water depth, channel width, current velocity, water discharge, and tides which was conducted every 3 hours at three different water depth. On Jumada I (Jumadil awal) 1-29, 1435 Hijra, the highest and lowest water depth of 6.06 and 3.82 meters occurred in the 23rd and 10th day at 09:00 and 16:00 local time, respectively. The highest and lowest velocity of 0.357 and 0.01 m/s occurred in the 15th and 18th day at 09:00 and 12:00 local time, respectively. The strongest and weakest discharges of 177.93 m3/s and 9.47 m3/s occurred in the 12th and 28th day at 09:00 local time, respectively. The results found a strong correlation between water discharge and current velocity. Thus water discharge and currents play an important role in the channel stability and in controlling sea transportation in terms of scheduling the departures and arrival of ships.
Biodiversity of macroalgae in Pari Island
Authors: Srimariana E S , Kawaroe M , Lestari D F , Setyaningsih WA , Nugraha A H
Published: January 2020

Macroalgae is one of the marine biological resources that have the potential to be utilized further by humans. This research aims to study macroalgae diversity in Pari Island. The study was conducted at two stations using the line transect method at the reef flat area. The results of this study indicate that there are 3 class macroalgae found in Pari Island. 17 species of macroalgae found in the south of Pari Island and 10 species found at the North of Pari Island. Macroalgae species with high abundance are Padina minor and Halimeda opuntia. The highest macroalgae diversity was found at south Pari Island with a diversity value index 2.02.
Assessment of coral reefs health in Nature Recreation Park (TWA=Taman Wisata Alam) Sangiang Island, Banten
Authors: Idris  , Putri A R , Adiwijaya C , Gilang M , Santoso P , Prabowo B , Muhammad F , Andriyani W , Lestari D F , Setyaningsih W A , Zamani N P
Published: January 2020

Sangiang Island had been established as a Nature Recreation Park (TWA) in Indonesia, that requires comprehensive data support for good management. The rise of marine tourism that increased in TWA Sangiang Island behoove to be a concern, especially in coral reef ecosystem. The study aimed to determined the condition of the coral cover and the biomass composition of coral reef fishes, then to identify parameters that affect coral health and the coral reefs health index in TWA Sangiang Island. The observation was carried out in area near to the estuary (Legon Waru), entry point for shipping (Tembuyung), and diving tourism (Legon Bajo). The highest of biomass of target fish was Legon Bajo (0.013 kg / ha) and the lowest was Tembuyung (0.002 kg / ha). Coral reefs health index values in each station varied from 1 (low) to 4 (high). Coral reefs health index in Legon Waru was strongly influenced by live coral cover, and also in Legon Bajo was influenced by live coral cover, rubble and biomass of target fishes, while in Tembuyung was much influenced by fleshy seaweed cover. The results indicated that the coral reef ecosystem on Sangiang Island wasn’t in good condition as a whole.
The potential role of eutrophication, tidal and climatic on the rise of algal bloom phenomenon in Jakarta Bay
Authors: Sidabutar T , Srimariana E S , Wouthuyzen S
Published: January 2020

Over the past several years, a number of algal bloom incidents has been increasingly observed in Jakarta Bay. The increasing frequency of algal bloom incidents, and subsequent environmental impacts are a rising threat to the coastal resources, economy and public health. Eutrophication, tidal and climatic are the three processes that suspected to have a potential role with algal bloom incidences in this bay. To understand the role of these three processes, a monitoring program had been conducted from 2008 until 2015. The study reveals that algal bloom occurrences have a strong relationship with major nutrients ratio. Besides that, the bloom incident occurred particularly after the rainy season to dry season. The tides have a potential role in the spread of bloom formation and stratification. During the study the concentration of phosphate in these waters ranging from 0.01-2.5 μg/L and nitrate 0.01-15.89 μg/L. The ratio of major nutrient (N/P ratio) in this waters ranging from 0.2 - 45.4. The N/P ratio tends to be higher in 2010, where the abundance of phytoplankton raising conspicuously. The N/P ratio may controlling the occurrences of algal bloom, while tidal responsible in bloom distribution, and climatic particularly precipitation, effecting nutrients availability.
Thermal dispersion model of cooling water discharges from industrial activities of steam power plants (PLTU) on the north coast of Paiton, East Java
Authors: Fikri M Y , Atmadipoera A S , Nurjaya I W
Published: January 2020

Necessity electricity in the society especially in industrial activities every year there is an increase in demand. The technology that used in production electricity is one of the Steam Power Plant (PLTU), where Paiton Power Plant is one of the largest power plant in Indonesia and can distribute electricity to Java and Bali. The purpose of this research is to know the process of hot water waste distribution from PLTU Paiton either horizontally or vertically with observation method and numerical model. Tidal model validation with observation data has a high correlation value (r = +0,908). Validation model of hot water waste distribution on surface with observation result has RMSE value equal to (e = 0,96). The observation results show the temperature of the hot water waste in front of the outlet is recorded between 30 °C to 40 °C. Vertically, the distribution of hot water waste near the outlet reaches a depth of 5 m and horizontally the thickness becomes thinner at a distance of about 500 m from the outlet mouth. The model result shows that the distribution of hot water waste distribution occurs more broadly when the low tide.
Monsoonal distribution of phosphate within Tallo Estuary, South of Sulawesi
Authors: Rastina  , Nurjaya I W , Prartono T , Sanusi H
Published: January 2020

Phosphate is one indicator of water fertility and is needed to support the life of organisms, especially phytoplankton. The main source of phosphate in the waters naturally originates from the processes of decomposition, weathering or decomposition of plants and comes from the remains of dead organisms. Besides this phosphates in coastal areas are sourced from rivers that carry waste from land, so phosphates in the river mouth are larger than the surrounding waters. The purpose of this study was to describe the pattern of phosphate distribution in the West and East seasons in the Tallo estuary, Makassar using hydrodynamic and distribution models of pollutants. The results of this study indicate the pattern of spreading phosphate in the study site is strongly influenced by oceanographic conditions of the waters.
Potential of associative bacteria isolates from seagrass ecosystem
Authors: Ismet M S , Jayenti E D , Ismiati P , Utomo R P , Srimariana E S , Hastuti Y P
Published: January 2020

The seagrass ecosystem is rich in organic materials such as nitrates, carbon, and phosphates. Potential nutrient content available in water and sediments influences the presence of an associative bacterial community. This study aimed to explore associative bacteria in seagrass ecosystems which have potentially producing antibacterial activity and cellulase enzymes. Associative bacterial isolation was carried out on sediment samples and seagrass leaves Thalassia hemprichii which was found as the dominant ecosystem compiler. The antibacterial test was carried out using agar diffusion method against Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, and Vibrio parahaemolyticus. Meanwhile, assay on cellulase activity of the actinomycetes bacteria was using agar diffusion method on CMC media. Isolation of endophytic bacteria of seagrass leaves produced 12 isolates with 2 isolates which could inhibit all targeting bacteria and 3 isolates which could inhibit several targeting bacteria. ANOVA test showed that the sampling location significantly affected the antibacterial activity. Meanwhile, 5 isolates of actinomycetes bacteria were found from the sediments, with 4 isolates having cellulase activity. ANOVA test showed that cellulase activity of the actinobacteria was associated with the density of Cymodocea rotundata and T. hemprichii seagrass species with moderate to high category.
Developing signal processing of echo sounder for measuring acoustic backscatter
Authors: Manik H M , Nishimori Y , Nishiyama Y , Hazama T , Kasai A , Firdaus R , Elson L , Yaodi A
Published: January 2020

The method used to determine the condition of marine biological resources is still conventional, not systematic and not comprehensive. So far, the methods used include divers where the depth of observation is very limited. Another method using sonar for which the acquisition of data is still qualitative. For this reason, it is necessary to strive for new methods that can guarantee careful and accurate observation. This study proposes the detection, classification and quantification of underwater target algorithms using Intelligent Biomass Active Sonar Transducer (IBAST) using a microcontroller unit. IBAST uses acoustic pulses and features that are narrow spectral so as to provide the ability to detect underwater targets (underwater targets) accurately and be able to classify such targets as fish, zooplankton, marine mammals, coral reefs, and other targets. IBAST uses a tracking algorithm and output detector which reduces errors in target detection. The application of the algorithm will be carried out to test the classification method and quantification of underwater targets. This research is very useful in the aspects of quantification of marine life, protection of fishery resources and seabed habitat.
N3-AUV (Nusantara 3-Autonomous Underwater Vehicle): design and implementation for underwater exploration
Authors: Ratnasari Y , Pandewo A F , Santoso S A , Anas D F , Lestari N A , Iqbal M , Jaya I
Published: January 2020

Autonomous Underwater Vehicle (AUV) is a type of underwater robot that can move and perform pre-assigned the missions based on a program which is installed in the microprocessor in the body of the vehicle. AUV uses thrusters to maneuver underwater and may be supported by a compass, various sensors, and a camera that are attached to the vehicle. In this paper, we present the development of N3-AUV and a pool test of this performance. N3-AUV uses 8 thrusters, 2 webcam cameras, Raspberry Pi, a depth sensor, and a compass. The vehicle has a torpedo-like shape so that it is easier to move underwater relatively faster. With 2 webcam cameras, where the first one is placed under the frame to record images of the conditions beneath the vehicle and the second one is placed in front of the frame to record the conditions in front of the vehicle. A pool test was conducted by means of pre-assigning missions, such as navigating pass the goal post, and finding and knocking down an underwater object. N3-AUV can complete three mission of four. Missions that have been carried out successfully are navigation, acquisition, and localization. N3-AUV has a maximum speed of about 1 m/s.
Spatial and temporal variability of geostrophic currents in the Indo-Australian Basin using gridded ARGO Float data
Authors: Saputra J , Gaol J L , Panjaitan J P , Atmadipoera A S
Published: January 2020

Geostrophic current variability in the Indo-Australian Basin (IAB) of eastern Indian Ocean is analyzed by using monthly gridded salinity and temperature data sets (between 2004 and 2016), from CTD ARGO Float. Geostrophic current is derived from dynamic height calculation. We applied time-series EOF analysis by decomposing geostrophic zonal component into dominant variability in several major modes. The variability of geostrophic currents from CTD Argo data analysis had differences, both spatial and temporal variability. There were four major modes, accounting for of 50.47% of the sum explained variance. The anomaly that occurred near the southern coast of Java cannot be detected due to the limited spatial coverage of the ARGO Float distribution. The spatial pattern in the first mode was indicated by positive anomaly at 110°E-114°E and 7°S-13°S. Furthermore, negative anomaly showed in the southern part of the study area. Variability oscillated with annual, semi-annual and inter-annual periodicity. In the second mode, there was a negative anomaly at 10°S-16°S, the rest of area were shown as the positive anomaly. Variability oscillated with semi-annual, annual and interannual periodicity. In the third and fourth mode, they showed variability with the semiannual, annual and inter-annual periodicity.
Waveform re-tracking analyses with Fuzzy Logic on altimetry satellite data in Natuna Waters
Authors: Permana R D , Nababan B , Panjaitan J P
Published: January 2020

Waveform re-tracking analyses have been proven to increase the accuracy of sea surface height (SSH) estimation from satellite altimeters specifically in coastal areas. However, each re-tracking algorithm has its strengths and weaknesses so that no dominant algorithm can be applied to any water condition. The study purpose was to obtain the best SSH estimation from altimeter satellite data using waveform re-tracking analyses with fuzzy logic system. The fuzzy logic system was used to select the best SSH values from the results of waveform re-tracking analyses. The data used in this study were level-2 SGRD data from Jason-2 and Jason-3 in Natuna Waters in 2016-2018. Waveform re-tracking with fuzzy logic system can reduce standard deviation of SSH up to 23.3 cm from the on-board (oceanic) algorithm standard deviation. The highest Improvement Percentage (IMP) value from each observation track was constantly generated by re-tracking with fuzzy logic system up to 70.3%. The result of this study showed that this analysis can produce SSH values with the best accuracy in each track observation.
Implementation of swarm intelligence algorithm on Autonomous Surface Vehicle (ASV)
Authors: Nugroho C A , Vidura A , Rahman M R , Iqbal M , Satria M G A , Jaya I
Published: January 2020

Swarm Intelligence (SI) is an artificial intelligence algorithm related with collective work of individuals intelligence. To date, SI has been developed and installed on autonomous surface vehicle (ASV). ASV use global positioning system (GPS) in determining position, relative orientation to other ASV, and ability to move to desire direction. Aim of this research is to designing ASV and then apply SI algorithm on three ASV to moving simultaneously with preprogrammed formation. These three ASV were divided into two parts, master ASV as a master (order giver) and slave ASV as ASV that follow master ASV. SI algorithm developed using python as its programming language. The formation developed in this research is line and triangle formations. The ASV has 68 x 35 x 20 cm dimension and 0.7 m/s maximum speed. Autonomous system test show that ASV can follow waypoint with 2.3 m and 2.4 m average error at X axis and Y axis and the three-ASV can communicate each other to make formation.
Real-time reef fishes identification using deep learning
Authors: Yusup I M , Iqbal M , Jaya I
Published: January 2020

Reef fishes is an important part in maintaining the balance of various components in the coral reef ecosystem. The existence of reef fish on coral reef ecosystems is a marker of the ecosystem in good condition. Furthermore, it is important to observe the condition of reef fish in a coral reef ecosystem to determine the population and diversity of reef fish in the ecosystem. Observation of reef fish generally by performing a manual visual census by scuba diver. In entering the industrial revolution 4.0 era there is a need to develop technology that is used to monitor the condition of reef fish in a coral reef ecosystem. The development of technology will certainly help researchers, and later on ecosystem manager, in observing the condition of reef fish with automatic identification. The technological development that can be done to observe reef fish is by applying deep learning. In this research we used YOLO deep learning algorithm for automatic identification. YOLO has the advantage of faster object detection. Application of deep learning to identify fish automatically is illustrated using underwater video recording of reef fish.
The relationship between shrimps production and mangrove ecosystem in Indramayu Regency
Authors: Dheanisa M R , Handayani T , Susiloningtyas D , Rahatiningtyas N S
Published: January 2020

Shrimp is one of the agricultural commodities which has high economic value with global and increasing market value abroad. Thus, Shrimp production continues to increase. Shrimp production in Indramayu Regency in 2017 was 191,919.41 tons. This makes Indramayu Regency the largest producer of shrimp in West Java (BPS, 2017). Meanwhile, Mangrove is an area that has a high contribution. Mangrove ecosystems have an association with pond productivity. This study aims to analyze the productivity value of shrimp in Indramayu Regency and its effect on the mangrove ecosystem in Indramayu Regency in that particular area. The method that is used to change identify mangrove forests is Landsat 8 image then continued with composite band 564 and NDVI (Normalized Difference Vegetationation Index) with a distance of 1 Km, 2 Km, and 3 Km from the mangroves. Furthermore, the result of the interviews is used to find out the value of shrimp productivity. Analysis of data is calculated through regression methods to see the–relation proximity between shrimp productivity and mangroves. The regression result between the distance of mangroves and productivity yields with the value of R Square equals 71.7%. This result indicates a positive link between shrimp productivity and mangrove ecosystem.
Biodegradation of aliphatic waste components of oil sludge used micro symbiont of Sponge Niphates sp.
Authors: Marzuki I , Chaerul M , Erniati  , Asmeati  , Paserangi I
Published: January 2020

Investigation has been carried out using a sponge Niphates sp. as biodegradation agent of the aliphatic hydrocarbon component of crude oil sludge. The experiment was carried out by colonizing and making suspension of Bacillus pumilus strains GLB197 and Bacillus cohnii strains of DSM 6307, isolated from sponge Niphates sp. Both types of micro symbiont suspension were mixed with sludge waste for 30 days. There are five biodegradation parameters observed, carried out every five days of incubation. Parameters that observed during incubation were pH, gas bubbles and fermentation odor. Meanwhile, the optical density of the media was measured using spectrometer-D20+, Aliphatic components degradation was measured using GC-MS. Observation of biodegradation parameters showed there was a change in pH from 7 to 6, formed gas bubbles, resulting in fermentation odors and showed an increased optical density by an average of 35%. These four parameters occur during the interaction of 10-20 days of interaction in the media. There were 20 types of aliphatic components identified in the crude oil sludge waste. Analysis of four aliphatic components, namely Tridecane, Octadecane, Tricosane, and Nonacosane showed a decrease in the average concentration of 48.11 %.
Productivity and decomposition rate of Rhizophora mucronata and Avicennia alba litter based on environment characteristics in Muara Gembong
Authors: Muliawan R E , Prartono T , Bengen D G
Published: January 2020

Mangrove forests damage may decrease their function and ecological role in relation to litter production which support the sustenance of aquatic resources. This research aimed to determine and estimate productivity and decomposition rate of mangroveRhizophora mucronataandAvicennia albalitter, and their effect on water nutrients. The research was conducted at three stations in Pantai Mekar Village, Muara Gembong District for 60 days observation during period of April–September 2018. Litter productivity was measured using litter traps and litter decomposition rate was estimated using litter bags. The concentration of water nutrient (nitrate, ammonium and phosphate) was obtained through a laboratory analysis. Litter productivity ofR. mucronataandA. albastands reached 4.68 and 7.11 g m−2day−1respectively with the biggest contributed from leaves litter. Observed different rates of mangrove decomposition was due to the lignin content. The decomposition rate ofR. mucronataandA. albawere Y=12.841e−0.382X(R2=0.97) and Y=11.958e−0.478X(R2=0.91) respectively. The productivity and decomposition rate ofA. albalitter was greater and faster thanR. mucronata. Increased nitrates was indicated of nitrification process, while phosphate and ammonium showed decreased concentration during experiments. Aside from that, water nutrient concentration was affected by dissolved oxygen availability.
Baseline concentration of Polonium-210 (210Po) in several biota from Jakarta Bay
Authors: Makmur M , Prihatiningsih W R , Yahya M N
Published: January 2020

Nuclide 210Po is the main contributor to internal doses due to ingestion of radionuclide in humans, and enters the human body through the consumption of food, including seafood. The research aim is to analyse the activity of the 210Po, in several species of biota that commonly available in the Jakarta Bay. The sample consist of tuna, tenggiri (mackerel), kakap merah (red snapper), Shrimp and green mussel were collected in 2017. The activity of 210Po in the edible part of that biota ranged from 9.05 ± 3.05 to 137.37±37 Bq/kg of fresh biota, and the highest activity in the green mussel and the lowest for tuna. This result were comparable to those presented by other study from several regions of the world and the UNSCEAR data. The daily intake of 210Po from these biota varied between 0.24 and 14.27 Bq year–1. The estimated dose of 210Po intake ranged from 0.03 – 3.6 μSv year–1 are lower than the average natural radiation received by humans globally. This study contributes to the Indonesia baseline data of 210Po in marine biota.