bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion-acoustic waves in dense magneto-rotating quantum plasma
Authors: Sahu Biswajit , Sinha Anjana , Roychoudhury Rajkumar
Published: July 2019

A theoretical study is presented for the oblique propagation of linear and nonlinear ion acoustic waves in a dense electron-ion quantum plasma, as that found in dense astrophysical objects like white dwarfs, rotating around an axis at an angle θ with the direction of the constant magnetic field B→=B0ẑ. In the absence of exact analytical solutions, we look for approximate ones by applying different approximation techniques like linearization, reductive perturbation, phase portraits, etc. The linear dispersion relation, obtained as a quadratic equation in the plasma frequency ω2, reveals interesting features. The small amplitude analysis for the nonlinear waves, using the reductive perturbation technique, yields the Korteweg–de Vries equation, whose solutions are solitary waves. The effects of various physical parameters like speed and angle of rotation, strength of the magnetic field, the quantum diffraction term, etc., on the shape of the nonlinear structures, are investigated numerically. It is observed that the different plasma parameters have similar effects on both small and arbitrary amplitude waves—stronger magnetic field, larger quantum effects, and higher speed of rotation decrease their width. Furthermore, as the angle between the rotation axis and magnetic axis decreases, i.e., the rotation is aligned with the direction of the magnetic field, the waves get sharper. Additionally, the energy of the small amplitude solitary wave decreases with an increase in the speed of rotation and stronger quantum effects.
Quantifying interdependence using the missing joint ordinal patterns
Authors: Yin Yi , Wang Xi , Li Qiang , Shang Pengjian , Hou Fengzhen
Published: July 2019

In this paper, we develop the concept of forbidden/missing ordinal patterns into the forbidden/missing joint ordinal patterns and propose the ratio of the number of missing joint ordinal patterns (RMJPs) as a sign of interdependence. RMJP in a surrogate analysis can be used to differentiate the forbidden joint ordinal patterns from the missing joint ordinal patterns due to small sample effects. We first apply RMJP to the simulated time series: a two-component autoregressive fractionally integrated moving average process, the Hénon map, and the Rössler system using active control and discuss the effect of the length of the time series, embedding dimension, and noise contamination. RMJP has been proven to be capable of measuring the interdependence in the numerical simulation. Then, RMJP is further used on the electroencephalogram (EEG) time series for empirical analysis to explore the interdependence of brain waves. With results by RMJP obtained from a widely used open dataset of the sleep EEG time series from healthy subjects, we find that RMJP can be used to quantify the brain wave interdependence under different sleep/wake stages, reveal the overall sleep architecture, and indicate a higher level of interdependence as sleep gets deeper. The findings are consistent with existing knowledge in sleep medicine. The proposed RMJP method has shown its validity and applicability and may assist automatic sleep quantification or bring insight into the understanding of the brain activity during sleep. Furthermore, RMJP can be used on sleep EEG under various pathological conditions and in large-scale sleep studies, helping to investigate the mechanisms of the sleep process and neuron synchronization.
Generating the polarization-controllable THz radiations by incommensurate two-color femtosecond laser fields
Authors: Li Ya-Ning , Wang Guo-Li , Zhang Lei , Jiao Zhi-Hong , Zhao Song-Feng , Zhou Xiao-Xin
Published: July 2019

We propose and demonstrate theoretically an effective way to generate polarization-controllable terahertz (THz) emission from the gaseous plasma. Compared to the previously used ω + 2ω two-color field, we show that the wavelength for the second pump laser pulse in the combination field, which is composed of a circularly polarized laser field and a linear laser pulse, is a key factor for controlling the polarization of emitted THz waves. By choosing an appropriate laser wavelength, intense linearly, elliptically, and circularly polarized THz radiation can be generated in a wide bandwidth range. Our simulations also show that for such an incommensurate two-color femtosecond laser field, its intensity ratio and phase delay between two components can also be used to control the polarization degree and direction of THz radiation. By utilizing the present laser technologies, our scheme can be implemented in the experiment.
Orbital stability of ensembles of particles in regions of magnetic reconnection in Earth's magneto-tail
Authors: Lhotka Christoph , Bourdin Philippe , Pilat-Lohinger Elke
Published: July 2019

We investigate the collective behavior of particle orbits in the vicinity of magnetic reconnection in Earth's magneto-tail. Various regions of different kinds of orbital stability of particle motions are found. We locate regimes of temporary capture of particle orbits in configuration space as well as locations, where strong particle accelerations take place. With this study, we are able to provide a detailed map, i.e., the topology, of high and low acceleration centers close to the reconnection site. Quasiregular and chaotic kinds of motions of elementary particles can be determined as well. The orbital stability of particle orbits is obtained by a statistical analysis of the outcome of the system of variational equations of particle orbits within the framework of particle-in-cell simulations. Using the concept of Lyapunov characteristic numbers to ensembles of particle orbits, we introduce Lyapunov ensemble averages to describe the response of particle orbits to local perturbations induced by the electromagnetic field.
A study of VUV emission and the extracted electron-ion ratio in hydrogen and deuterium plasmas of a filament-driven H−/D− ion source
Authors: Komppula J. , Tarvainen O. , Kalvas T. , Koivisto H. , Myllyperkiö P. , Toivanen V.
Published: July 2019

Vacuum ultraviolet (VUV) emission diagnostics for studying differences of electron impact processes in hydrogen and deuterium plasmas are presented. The method is applied to study a filament driven multicusp arc discharge negative ion source by comparing the VUV-emission intensities of different emission bands and extracted currents of H−/D− ions and electrons. It was found that the ratio of coextracted electrons to extracted ions is four times higher for deuterium than for hydrogen. No significant differences of the VUV-spectra or volumetric rates of ionization, excitation, production of high vibrational states, and dissociation were found between the plasmas of the two isotopes. The volumetric rates of these electron impact processes are presented for both discharges. It is concluded that in the filament ion source, the observed difference of H−/D− production through dissociative electron attachment is due to different diffusion rates across the magnetic fields of the tandem-type discharge chamber rather than the production rate of ground state molecules at their vibrational levels.
Some considerations on the water polymorphism and the liquid-liquid transition by the density behavior in the liquid phase
Authors: Mallamace Francesco , Corsaro Carmelo , Mallamace Domenico , Fazio Enza , Chen Sow-Hsin
Published: July 2019

The bulk liquid water density data (ρ) are studied in a very large temperature pressure range including also the glass phases. A thorough analysis of their isobars, together with the suggestions of recent thermodynamical studies, gives evidence of two crossovers at T* and P* above which the hydrogen bond interaction is unable to arrange the tetrahedral network that is at the basis of the liquid polymorphism giving rise to the low density liquid (LDL). The curvatures of these isobars, as a function of T, are completely different: concave below P* (where maxima are) and convex above. In both the cases, a continuity between liquid and glass is observed with P* as the border of the density evolution toward the two different polymorphic glasses (low and high density amorphous). The experimental data of the densities of these two glasses also show a markedly different pressure dependence. Here, on the basis of these observations in bulk water and by considering a recent study on the growth of the LDL phase, by decreasing temperature, we discuss the water liquid-liquid transition and evaluate the isothermal compressibility inside the deep supercooled regime. Such a quantity shows an additional maximum that is pressure dependent that under ambient conditions agrees with a recent X-ray experiment. In particular, the present analysis suggests the presence of a liquid-liquid critical point located at about 180 MPa and 197 K.
Identification of key sites controlling protein functional motions by using elastic network model combined with internal coordinates
Authors: Zhang Peng Fei , Su Ji Guo
Published: July 2019

The elastic network model (ENM) is an effective method to extract the intrinsic dynamical properties encoded in protein tertiary structures. We have proposed a new ENM-based analysis method to reveal the motion modes directly responsible for a specific protein function, in which an internal coordinate related to the specific function was introduced to construct the internal/Cartesian hybrid coordinate space. In the present work, the function-related internal coordinates combined with a linear perturbation method were applied to identify the key sites controlling specific protein functional motions. The change in the fluctuations of the internal coordinate in response to residue perturbation was calculated in the hybrid coordinate space by using the linear response theory. The residues with the large fluctuation changes were identified to be the key sites that allosterically control the specific protein function. Two proteins, i.e., human DNA polymerase β and the chaperonin from Methanococcus maripaludis, were investigated as case studies, in which several collective and local internal coordinates were applied to identify the functionally key residues of these two studied proteins. The calculation results are consistent with the experimental observations. It is found that different collective internal coordinates lead to similar results, where the predicted functionally key sites are located at similar positions in the protein structure. While for the local internal coordinates, the predicted key sites tend to be situated at the region near to the coordinate-involving residues. Our studies provide a starting point for further exploring other function-related internal coordinates for other interesting proteins.
Hot electron generation from a hole target for external electron injection into a laser-based accelerator
Authors: Neuberger I. , Oren G. , Henis Z. , Fraenkel M. , Zigler A.
Published: July 2019

We are proposing hot electrons source, which are suitable for external injection into a wakefield accelerator. Hot electrons with energies up to 3 MeV were generated by the interaction of femtosecond laser at an intensity of I=3.5×1018 W/cm2 with the preplasma produced in 25 μm holes, drilled in 1 μm Au foils targets. The preplasma created by the 1 ns prepulse preceding the intense main laser pulse generates an elongated plasma under the critical density and scale length of tens of microns. This plasma channel enables generation of high energy and collimated electron beam. The proposed approach can allow minimizing current, laser based electron accelerators, to produce a new X –ray source, to generate relatively long, high density plasma source, which important for study of nonlinear effects related to Laser Fusion and other applications.
Acoustic metamaterial antennas for combined highly directive-sensitive detection
Authors: Ma Chengrong , Gao Shuxiang , Cheng Ying , Liu Xiaojun
Published: July 2019

Detection of weak sound signals masked by strong noise background remains challenging in acoustic science and engineering. The major bottleneck of advancing this technology is the limited directivity and sensitivity of ordinary acoustic sensors. Here, we engineer acoustic metamaterials with a near-zero-index (NZI) in the form of a low-profile planarized acoustic antenna for combined highly directive-sensitive detection. The detectable incident angle can be substantially narrowed down by the directional selectivity of NZI acoustic metamaterials, while the detected pressure can be enhanced by deeply tunneling compression at the sound radiation vent. Magnification of signal amplitude more than 18 dB with a half-power beam width of mainlobe less than 5° is demonstrated both numerically and experimentally, which overcomes the detection limit of conventional acoustic sensing systems.
Evaporation sampled by stationary molecular dynamics simulation
Authors: Heinen Matthias , Vrabec Jadran
Published: July 2019

A nonequilibrium method is developed to sample evaporation of a liquid across a planar interface in a stationary scenario by molecular dynamics. The method does not rely on particle insertions which are challenging when they are used to maintain mass conservation. Its algorithm has a low complexity and is well suited for massively parallel simulations that may yield results with an excellent statistical accuracy. Spatially resolved classical profiles, e.g., for temperature, density, and force, are sampled with a high resolution for a varying hydrodynamic velocity of the evaporation flow. Relatively large systems are simulated, allowing for a detailed study of velocity distribution functions. Varying the hydrodynamic velocity from zero to the speed of sound, it is found that the evaporation flux increases asymptotically, reaching about 90% of its maximum value when the hydrodynamic velocity is about half of its maximum value. A deviation from the Maxwell distribution is identified for the transversal particle velocity near the interface which selectively hinders the migration of individual particles from liquid to vapor with its potential well, allowing only the faster ones to escape. The vapor region in the vicinity of the interface exhibits a spread between the transversal and longitudinal temperature, but equipartition is reattained through particle interactions such that Maxwell distributions are found at a certain distance from the interface. A detailed discussion of the atomistic mechanisms during evaporation is provided, facilitating understanding of this ubiquitous process.
Understanding the phase dependent energy storage performance of MnO2 nanostructures
Authors: Samal Rutuparna , Chakraborty Brahmananda , Rout Chandra Sekhar
Published: July 2019

We demonstrate charge storage mechanisms of four kinds of MnO2 polymorphs (α, β, γ, and δ) both in micro- and nanodimensions successfully synthesized by hydrothermal and microwave irradiation techniques. We observed that layered δ-MnO2, comprised of self-assembled nanoflakes oriented in different directions, shows a significantly improved capacitive behavior. The maximum achieved specific capacitance is 518 F/g at a current density of 3 A/g in a 3M KOH electrolyte solution, exhibiting a large capacity retention of 83.95% over 2000 consecutive charge/discharge cycles at a current density of 10 A/g. State of the art Density Functional Theory (DFT) simulations have also been performed to support experimental data. The quantum capacitance presented from DFT simulations predicts that the δ phase exhibits highest quantum capacitance, whereas it is lowest for the β phase supporting the experimental trend. Also, the structural features of wide tunnel size (∼7 Å) for the δ phase facilitates favorable insertion of cations, whereas narrow tunnel size (∼1.89 Å) for the β phase restricts the diffusion of charge particles yielding poor capacitance performance.
Computational study on thermodynamic properties of Fischer-Tropsch synthesis process
Authors: Zhu Hong-kun , Song Guo-liang , Li Zhen-hua
Published: July 2019

Using the highly accurate G4 method, we computed the thermodynamic data of 1287 possible reaction products under a wide range of reaction conditions in the Fischer-Tropcsh synthesis (FTS) process. These accurate thermodynamic data provide basic thermodynamic quantities for the actual chemical engineering process and are useful in analyzing product distribution because FTS demonstrates many features of an equilibrium-controlled system. Our results show that the number of thermodynamically allowed products to increase when lowering temperature, raising pressure, and raising H2/CO ratio. At low temperature, high pressure and high H2/CO ratio, many products are thermodynamically allowed and the selectivity of product has to be controlled by kinetic factors. On the other hand, high selectivity of lighter products can be realized in thermodynamics by raising temperature and lowering pressure. We found that the equilibrium product yield will reach a maximum and remain unchanged when lowering temperature, raising pressure, and raising H2/CO ratio to some limits, implying that optimizing reaction conditions has no effect on equilibrium product yields beyond these limits. The thermodynamic analysis is also useful in designing and evaluating FTS reaction mechanisms. We found that reaction pathways through formaldehyde should be discarded because of its extremely low equilibrium yield. Recently, in the FTS process using metal-oxide-zeolite catalysts for the highly selective production of C2—C4 olefins and aromatic hydrocarbons, there are several guesses on the possible reaction intermediates entering the zeolite channel. Our results show that ketene, methanol, and dimethyl ether are three possible reaction intermediates.
Near ambient pressure adsorption of nickel carbonyl contaminated CO on Cu(111) surface
Authors: Wang Rui , Ding Ding , Wei Wei , Cui Yi
Published: July 2019

Formation of volatile nickel carbonyls with CO in catalytic reaction is one of the mechanisms of catalyst deactivation. CO is one of the most popular probe molecules to study the surface properties in model catalysis. Under ultra-high vacuum (UHV) conditions, the problem of nickel carbonyl impurity almost does not exist in the case that a high purity of CO is used directly. While in the near ambient pressure (NAP) range, nickel carbonyl is easily found on the surface by passing through the Ni containing tubes. Here, the NAP techniques such as NAP-X-ray photoelectron spectroscopy and NAP-scanning tunneling microscopy are used to study the adsorption of nickel carbonyl contaminated CO gas on Cu(111) surface in UHV and NAP conditions. By controlling the pressure of contaminated CO, the Ni-Cu bimetallic catalyst can form on Cu(111) surface. Furthermore, we investigate the process of CO adsorption and dissociation on the formed Ni-Cu bi-metal surface, and several high-pressure phases of CO structures are reported. This work contributes to understanding the interaction of nickel carbonyl with Cu(111) at room temperature, and reminds the consideration of CO molecules contaminated by nickel carbonyl especially in the NAP range study.
Single-atom protecting group for on-surface synthesis of graphdiyne nanowires
Authors: Shan Huan , Mao Ya-hui , Zhao Ai-di
Published: July 2019

On-surface synthesis of semiconducting graphdiyne nanowires usually suffer severe side reactions owing to the high reactivity of the butadiynylene units at noble metal surfaces, limiting the production of isolated nanowires. In this work, we report the high-yield synthesis of branchless graphdiyne nanowires [-C≡C-Ph2-C≡C-]n via on-surface Ullmann coupling of 1,4-bis(4-bromophenyl)-1,3-butadiyne molecules with chemical vapor deposition method. Non-contact atomic force microscopy with single-bond resolution reveals that single gold adatoms act as effective protecting groups for butadiynylene units by forming Au-π ligand bonds, preventing unwanted branched coupling reactions and enabling the synthesis of ultralong isolated graphdiyne nanowires. This study will stimulate further investigation on the role of various surface adatoms in protecting on-surface reactions.
Absorption spectrum of neutral krypton in the near infrared region
Authors: Jiang Ruo-yu , Ye Jia , Deng Lun-hua , Wang Hai-ling
Published: July 2019

High-resolution absorption spectra of atomic krypton in the range of 11870–12700 cm−1 were recorded by employing concentration modulation absorption spectroscopy technique with a tunable single-mode cw Ti:Sapphire laser. The krypton atoms were excited to the absorbing energy states by discharge-burning in a mixture of helium and krypton. A total of 120 lines of neutral krypton were observed, among them 33 lines had already been classified in previous studies, 45 lines were newly classified with the known energy levels, and 42 lines cannot be classified. These unclassified lines indicate that up to now unknown energy levels of Kr must exist. Further, an analysis of the unclassified lines to get possible new energy levels with a classification program is reported.
Energy transfer and electron transfer in composite system of carbon quantum dots/rhodamine B molecules
Authors: Wei Kang , Zhang Lei , Jiang Shen-long , Zhang Qun
Published: July 2019

In this work, we investigated the energy transfer (EnT) and electron transfer (ET) processes as well as their relationship in the carbon quantum dots/rhodamine B (CQDs/RhB) including o-CQDs/RhB and m-CQDs/RhB systems by using photoluminescence spectroscopy in combination with steady-state and transient absorption spectroscopy. We found that the ET process is negligible in the o-CQDs/RhB system with an EnT efficiency as high as 73.2%, while it becomes pronounced in the m-CQDs/RhB system whose EnT efficiency is lower than 33.5%. Such an interplay of EnT and ET processes revealed in the prototypical composite system consisting of carbon quantum dots and dye molecules would provide helpful insights for applications of relevance to exciton quenching.
Simultaneous reproduction of two killifish congeners in the highly alkaline Lake Salda (Turkey)
Authors: Yoğurtçuoğlu Baran
Published: July 2019

The reproductive ecology of Western Palaearctic killifishes is poorly documented and was addressed in this study by investigating, for the first time, two closely related endemic killifish species, namely Aphanius fontinalis and Aphanius saldae. Fish samples were collected monthly from January to October 2017 to test whether the killifishes reproduce simultaneously in the highly alkaline Lake Salda (Turkey). Variation in the mean gonadosomatic index and the frequency of hydrated oocytes indicated that the two species reproduce synchronously from April to September. The timing of reproduction was affected more by day length than by water temperature. Larvae of a parasitic nematode (Eustrongylides sp.) were also observed in the gonadal tissue of some individuals. The effects of parasite infection on basic reproductive parameters were tested in A. fontinalis. Parasite infection had no significant effect on gonad weight, but was associated with significantly decreased fecundity and oocyte diameter. In both species, fecundity was related to fish size; however, the regression model showed non-significant results for the parasite-infected A. fontinalis subsamples. Further research is needed to address the ecological and evolutionary consequences of the coexistence of A. fontinalis and A. saldae and the overlap in breeding seasons.
Rethinking irrigation modernisation: realising multiple objectives through the integration of fisheries
Authors: McCartney Matthew P. , Whiting Louise , Makin Ian , Lankford Bruce A. , Ringler Claudia
Published: July 2019

Irrigation has been, and will remain, instrumental in addressing water security (Sustainable Development Goal (SDG) 6), food insecurity (SDG 2) and poverty (SDG 1) goals. However, the global context in which irrigation takes place is changing rapidly. A call for healthier and more sustainable food systems is placing new demands on how irrigation is developed and managed. Growing pressures from competing water uses in the domestic and industrial sectors, as well increasing environmental awareness, mean irrigation is increasingly called on to perform better, delivering acceptable returns on investment and simultaneously improving food security, rural livelihoods and nutrition, as well as supporting environmental conservation. Better integration of fisheries (including aquaculture) in irrigation planning, investment and management can contribute to the modernisation of irrigation and the achievement of the multiple objectives that it is called on to deliver. A framework illustrating how fisheries can be better integrated with irrigation, and how the two can complement each other across a range of scales, from scheme to catchment and, ultimately, national level, is presented.
Improved properties of Ti-6Al-4V by combining isothermal equal-channel angular processing and hot-extrusion
Authors: Arabi Hamid , Ketabchi Mostafa
Published: July 2019

The aim of this work was to study effects of hot extrusion on the microstructure of Ti-6Al-4V (wt-%) alloy processed by ECAP. Firstly, an isothermally Ti–6Al–4V alloy processed by Equal channel angular pressing(ECAP) was preheated at 950°C for 6 min and then hot extruded at 900°C. The hot extrusion minimised the grain size and maximised the mechanical strength. Therefore, it was demonstrated that hot extrusion of Ti-6Al-4V alloys that processed by ECAP could be performed without compromising any mechanical properties. Therefore, it is possible to use the ability to apply a reduced cross-section in hot extrusion for an Ti-6Al-4V processed by ECAP without concern about the reduction of properties.
Microstructure inhomogeneity of as-cast high-entropy alloy and heat treatment improvement
Authors: Nong Zhi-Sheng , Zhang Zu-Ping , Wang He-Nan , Deng Xi-Guang
Published: July 2019

In order to clarify the microstructure inhomogeneity of as-cast high-entropy alloy synthesised by vacuum arc melting, the microstructures, hardness, and chemical compositions of as-cast CrCuFeMnTi alloy have been investigated from the surface to the interior. The results show that obvious microstructure coarsening accompanied by a decrease in hardness occurred from the surface to the interior. The microstructures and hardness of CrCuFeMnTi alloy distributed relatively uniformly from the surface to the interior when the alloy was annealed at 500°C. The numerical fluctuation of the element distributions with the increase in depth also presented a more stable condition. In addition, electrochemical corrosion tests at different positions of the specimens further illustrated the effect of microstructure inhomogeneity on the corrosion tendency and rate.
High return to competition rate following ACL injury – A 10‐year media‐based epidemiological injury study in men's professional football
Authors: Krutsch Werner , Memmel Clemens , Krutsch Volker , Angele Peter , Tröß Tobias , Aus Der FÜnten Karen , Meyer Tim
Published: July 2019

Ruptures of the anterior cruciate ligament (ACL) typically occur in professional football and epidemiological data about longitudinal injury development is needed. This practice‐driven investigation of media‐derived ACL data provides information about professional football over 10 years. Injury registration was based on “kicker” sports magazine information that have been recorded over one decade in a standardized manner. Only ACL ruptures in the first German football league were included when they could be verified by a second reliable source. Level of evidence: III. Fifty‐seven primary ACL ruptures were verified in the first German football league during the seasons 2007/2008 to 2016/2017. Among them, six re‐injuries were found. Mean age at the time of injury was 24.8 years (SD 3.8). 31% (n = 20) of ACL ruptures occurred at the beginning of the season in August or September (p = 0.02). Mean time of RTC after primary ACL ruptures was 226.7 days (SD: 93.5) and 245.6 days (SD: 45.4) after re‐injury. Although 62 (98%) players returned to football after injury and only one player immediately finished his career, 54.9% of the affected individuals played 3 years after the ACL rupture in the same league. ACL ruptures lead to longer absence than 7 months from football but does not give reason for immediate career‐ending. The decrease in playing level after 3 years illustrate the serious consequences of ACL ruptures in football. Media‐based injury reports may provide interesting information.
Collective operations can extremely reduce work fluctuations
Authors: Perarnau-Llobet Martí , Uzdin Raam
Published: July 2019

We consider work extraction from N copies of a quantum system. When the same work-extraction process is implemented on each copy, the relative size of fluctuations is expected to decay as

1

/

N

. Here, we consider protocols where the copies can be processed collectively, and show that in this case work fluctuations can disappear exponentially fast in N. As a consequence, a considerable proportion of the average extractable work



can be obtained almost deterministically by globally processing a few copies of the state. This is derived in the two canonical scenarios for work extraction: (i) in thermally isolated systems, where



corresponds to the energy difference between initial and passive states, known as the ergotropy, and (ii) in the presence of a thermal bath, where



is given by the free energy difference between initial and thermal states.
Cellulose-based nano hydrogel from corncob by gamma irradiation
Authors: Nurfadila  , Maddu A , Winarti C , Kurniati M
Published: July 2019

Based on economic nomenclature of Indonesian food crops, corn is the second important commodity after rice. The high corn production correlates with corncob waste produced. The existence of corncob waste is abundant and continuous post-harvest. One alternative to utilize of corncob waste is the high content of cellulose processed to cellulose-based nano hydrogel. In this study, cellulose from corncob was processed into hydrogel by gamma irradiation. Cellulose size reduction is done by the wet milling process. The treatment tested of nano hydrogel control was cellulose dissolved in NaOH/PEG solvent whereas the ratio of cellulose: solvent was 1:2 and 1:4 and nano hydrogel by gamma irradiation that nano-cellulose solution was filtered by vacuum filtration. The aim of this research was to find out the characteristics of nano hydrogel by gamma irradiation. Parameters observed were swelling ratio, gel fraction, texture and morphology. The result showed that the treatment test of nano hydrogel without gamma radiation has 111% and 127% swelling ratio, meanwhile, nano hydrogel with gamma irradiation has a 214% swelling ratio, 99% gel fraction and 1.17 mJ hardness with morphology showed higher porosity. The higher swelling ratio of nano hydrogel by gamma irradiation has the potential for application in agriculture as water absorbent material and fertilizer carrier agent.
Effects of nutrient composition on the formation of biofilm and biocorrosion in MEOR biostimulation medium based on response surface methodology
Authors: Purwasena I A , Astuti D I , Intan T , Lani D , Rodiana W N
Published: July 2019

Nutrition addition in Microbial Enhanced Oil Recovery (MEOR) application is one of the methods used to increase oil production. Nutrition injection in MEOR application must be done carefully because the lack of proper nutrition addition can induce biofilm and biocorrosion formation. The composition of biostimulation medium for optimizing beneficial indigenous bacterial growth in Microbial Enhanced Oil Recovery (MEOR) was evaluated using Response Surface Methodology (RSM) with Central Composite Design (CCD). Three main factors for the medium composition were molasses, Diammonium Phosphate (DAP), and NPK. The RSM was used to know the most effective medium composition towards biofilm production and strength that high potential leads to biocorrosion. Molasses, NPK, and diammonium phosphate (DAP) are utilized as carbon, nitrogen, and phosphate supplementary substrate in Brine water as basal medium. Molasses concentration was 0%-10% while DAP and NPK was 0%-0.5%. Both aerobic and anaerobe sessile bacteria, as well as acid producing bacteria, were enumerated by total plate and turbidity methods. Statistical analysis with α=0.05 proves molasses give significance effect to biofilm strength and sessile anaerobic bacteria. DAP gives significance effect to biofilm strength and sessile aerobic and anaerobic bacteria. NPK give significance effect to sessile anaerobic bacteria. Molasses addition decrease brine pH by microbial activity, make the carbon steel coupon ST-37 corrosion rate increased. Meanwhile, the addition of DAP increased the pH of brine medium and decrease the corrosion rate.
Improving prediction accuracy of classification model using cascading ensemble classifiers
Authors: Aziz A A , Indahwati  , Sartono B
Published: July 2019

One way to improve the accuracy of predictive modeling is by combining the models. This research tries to study local cascade. It combined one or more base classifier sequentially. In each stage, the probability prediction of the base classifier was inserted to the data. The data then modeled using a decision tree algorithm. This process continued until the data is homogenous. In the original method, the base classifier used was non-ensemble classifier. Our study included bagging, boosting, and random forest as base classifiers. 11 dataset with binary response was used to assess the accuracy of this method. We also compared the accuracy of our method with others that were published between 1996 and 2009. We found that cascading ensemble classifier slightly improve accuracy and performed better for a dataset with numerical predictors.
The dynamic structure of phytoplankton community in Segara Anak Lake: a volcanic lake in Mount Rinjani National Park
Authors: Arianto T , Qayim I , Damar A
Published: July 2019

Segara Anak is a volcanic lake located in the Mount Rinjani National Park, West Nusa Tenggara, Indonesia. It covers an area of ± 11.3 km2 with a maximum depth of 230 m at 2010 m.a.s.l. Segara Anak one of tourism object around Rinjani Mountain. The purpose of this research was to study the phytoplankton community structure and physical and nutritional factors correlation in Segara Anak spatially and temporally. The sampling technique used was a purposive sampling method. The samples were taken at five stations with an increasing depth of 1 m, 5 m, and 10 m respectively. The sample collection was started from October to December 2017. The data were analyzed using One-way ANOVA, Kruskal Wallis, Cluster Analysis and Principal Component Analysis. We identified 19 phytoplankton genera with 4 classes. The phytoplankton structure, nutrient, and physical factors are significantly different in spatial depth and temporal sampling. The abundance of phytoplankton in Segara Anak is dominated by the Cyanophyceae class.
Integrated information system development planning at tropical biopharmaca research center using enterprise architecture planning
Authors: Larasati  , A Kusuma W
Published: July 2019

Tropical Biopharmaca Research Center (Trop BRC) of Bogor Agricultural University (IPB) is a national research center that has the vision to become an international standard research center. To achieve this vision, Trop BRC IPB has to improve its quality of all aspects, such as by developing an integrated information system. Trop BRC IPB requires an integrated information system to manage its research activities and enterprise data more effectively. This study aims to define the architecture requirement that supports Trop BRC IPB’s business process and to guide the development of an information system using Enterprise Architecture Planning (EAP) method and Zachman framework. This study is conducted in the following stages, including preliminary planning, review of an existing enterprise, architectural design, and implementation planning. The results of this study are represented on tables, matrices, and diagrams that define the needs of data architecture, applications, and technology which can be used as a blueprint for applications developer team of Trop BRC IPB to develop and implement an integrated information system.
Anaerobic digestion of solid and liquid organic waste with microorganism from manure
Authors: Zaeni A , Susilowati P E , Harlia  , Rasmin N
Published: July 2019

Biogas is a valuable byproduct of anaerobic digestion of organic compounds. Biogas production depends on various factors including pH, temperature, microbes, substrate, and C/N ratio. From anaerobic digestion product, we can obtain not only fertilizer (Inhibition of anaerobic digestion process: A review, Volume 99, Issue 10, 2008) but also Biogas that could be used for cooking, lighting, and electricity. This research aims to obtain biogas from solid waste (household waste) and liquid waste (sago processing waste) added microbe from cow rumen and municipal sediment. These research steps are (1) biogas production; (2) methane gas analysis. The Result of this research indicates that methane gas is able to be generated from several variations (s) of waste: bacteria mixture. The result showed that high biogas production from household wastes was obtaining at 7% (b/v) concentration of waste, 0.5% (b/v) urea, and ratio microbial of municipal sediment and rumen was 2:3 at 5% (b/v), the incubation period was 35 days. The Total volume of biogas was resulted by 687 mL biogas/gram waste that consist(s) of 165.56 mL gas of CO2 and 521.44 mL gas of CH4 (75.89% (v/v)). Maximum biogas production is recorded from water sago processing waste treatment (1 L) added with bacteria from cow rumen 18x1010 bacteria. Fermentation duration is 84 days. Total of biogas generated is 17,481 L consisting of 105.37 mL CO2 (0.60% v/v) and consisting of biogas without CO2 17,375.63 L (99% (v/v)).
Utilization of cyanobacteria in photovoltaic technology
Authors: Indro M N , Maddu A , Eviana E
Published: July 2019

Bio-photovoltaic is one of the energy-transfer technology that uses oxygenic photoautotrophic organisms to harvest light energy and generate electricity. The aerobic phototropic organisms such as blue-green algae primarily absorb solar energy in visible light areas (400-700 nm). The design of a bio-photovoltaic prototype cell can be constructed using electrodes and Cyanobacteria put inside a plastic container. When the cell is irradiated the photosynthetic reactions will run and produce free electrons. Based on a previous result it is possible to put the cathodes inside the chamber or outside the chamber. In this research, the anode was variated using copper, stainless steel, and zinc. For the measurement while all of the electrodes are in the chamber the efficiency value of each metal is 0.094%; 0.3475%; 4.1026% with the fill factor value of each metal is 0.5719; 0.4204; 0.5776. On the other hand, when one of the electrodes is outside the chamber efficiency value of each metal is 0.0058%; 0.4949%; 1.3013% and the fill factor value of each metal is 0.5559; 0.3519; 0.4564.
Viscoelastic ferrocolloid modelled as the Jeffreys fluid: dynamic magnetic susceptibility in the presence of a bias field
Authors: Rusakov V V , Raikher Yu L
Published: July 2019

Orientational Brownian motion of a solid nanoparticle embedded in a viscoelastic medium modelled by the Jeffreys fluid is studied. The particle bears a magnetic moment and is subjected to a combination of a constant (bias) and a weak (probing) AC magnetic fields. First, the set of Langevin equations of the problem is presented and then on that basis a corresponding kinetic equation (KE) is derived. The solution of the KE that is linear with respect to the AC field amplitude is worked out. This solution is virtually exact since it is cast as a series that enables one to obtain the result with arbitrary accuracy. In that framework, a closed expression for the dynamic magnetic susceptibility of a statistical ensemble of magnetic particles in a viscoelastic environment is found, analyzed and compared to the previously existed approximate solution. It is shown that: (i) the dynamic elasticity of the medium has a substantial effect on the magnetic spectra; (ii) to correctly describe this effect, one has to retain a considerable number of terms in the series that presents the KE solution.
The influence of traveling magnetic field inductor asymmetric power supply on the liquid metal flow
Authors: Sokolov I , Shvydkiy E , Losev G , Bolotin K. , Bychkov S.
Published: July 2019

In modern times, exposure to a liquid metal by a travelling magnetic field is widely applied. There are laboratory studies on the processes of stirring and crystallization under the action of a traveling magnetic field. However, in the majority of studies it is assumed that the inductor power supply of the linear induction machine is carried out by a symmetrical three-phase system of currents with an equal phase shift, which, in some cases, is not quite correct. To approximate the model to real operating conditions, a numerical simulation of the magnetic field and the flow of liquid metal was carried out when supplied from a power source of symmetric three-phase voltage. The distortion of magnetic field, which, in turn, causes an nonuniform distribution of forces and the flow of a liquid metal, is shown. Evaluation of asymmetrical effect on the liquid metal flow was carried out by means of finite element method. That effect is caused by different coefficients of mutual coils induction of the linear induction machine, which is confirmed by experimental data.
Inductive methods of detection the boundary of electrically conductive media in experiment
Authors: Eltishchev V , Dimov I , Pavlinov A , Khalilov R , Kolesnichenko I
Published: July 2019

Induction methods of localization the electrically conductive media were implemented experimentally. Local and integral techniques are considered. Relations were represented between of the local level probe (LLP) signal, its position and the frequency of alternating current. The dependences of the integral level probe (ILP) signal on the frequency of the alternating current are obtained. The methods were tested in laboratory experiments in which it was possible to determine the metal level with an error not exceeding 1 mm. The LLP is more designed for small changes in the liquid metal boundary, comparable to the size of the probe. The ILP has its advantages when used in installations in which the change in the level of the liquid metal is greater than the pitch with which the measuring coils are installed.
Influence of aspect ratio on heat transfer in non-uniformly heated cylindrical fluid layers
Authors: Evgrafova A. , Sukhanovskii A.
Published: July 2019

In this paper experimental study of heat transfer processes in a cylindrical container non-homogeneously heated from below is presented. The heater has a circular form and was placed in the center of the vessel. The experiments were performed in the range of Rayleigh numbers from 4.4·106 to 1.2·107 and fixed Prandtl number (Pr = 67). Special attention was paid to the influence of the aspect ratio (the ratio of the height of the fluid layer to the diameter of the heater) on the flow structure and the intensification of heat transfer.
Electromagnetic flowmeter for wide-temperature range intensive liquid metal flows
Authors: Pavlinov A , Khalilov R , Mamykin A , Kolesnichenko I
Published: July 2019

The electromagnetic velocity sensor of Ricou and Vives with permanent magnet is well known. The probe is difficult to use at industrial conditions like metallurgy or nuclear power plants close to the Curie temperature. This article describes a reliable technique to provide controlled magnetic field distribution at the measurement area, generated by induction coils and concentrated by magnetic cores. The effect of magnetic field displacement, as well as weight and size of the assembled device, were minimized using numerical calculation of the field distribution for the case of a conducting media of different conductivity moving with different velocities. Calibration experiments showed high accuracy of measurements with low sensitivity to external electromagnetic noise.
Field-Induced Deformation and Structure Changes in a Magnetic Polymersome: Many-Particle Simulation
Authors: Ryzhkov A V , Raikher Yu L
Published: July 2019

Coarse-grained molecular dynamics simulation is performed to analyse structure and deformation response of a magnetic polymersome – a submicron hollow capsule whose membrane is made of amphiphilic block-copolymer, and the intramembrane space is filled with magnetic nanoparticles. The major prospects of these objects are related to controlled drug release. The developed many-particle model is used to calculate equilibrium magnetized configurations of polymersomes with different intensity of magnetic interparticle coupling. The analysis of those data reveals that under external magnetic field, an initially spherical capsule stretches along the field direction assuming a spheroid-like shape. This behaviour is caused by the field-driven tendency of the nanoparticles to aggregate inside the polymersome membrane. At weak interparticle magnetic interaction no extended chains are observed. Accordingly, the deformation and density redistribution are relatively small. In a polymersome with strong interparticle coupling the nanoparticles self-organize in long chains aligned with the field, and this induces considerable elongation of the polymersome along with accumulation of the majority of the nanoparticles in the “equatorial” zone of the membrane of the capsule.
Comparative Analysis of the Contact Deformation of the Spherical Sliding Layer of the Bearing with and without Taking into Account the Grooves with Lubricant
Authors: Adamov A A , Kamenskikh А А
Published: July 2019

In this paper, the analysis of the contact deformation of elements of spherical bearing through anti-friction polymeric layer made of modified fluoroplastic with and without taking into account the grooves with lubricant is carried out. The effect of grooves with lubricant on contact zone parameters is considered. Comparison of the results of the spherical bearing draft obtained within the framework of numerical and full-scale experiments with a constant coefficient of friction of 0.04 is made: at a nominal vertical load of 1000 kN, the difference between the results of numerical and full-scale experiments is minimal and is ∼ 7.13% for the model taking into account the grooves with lubricant. The analysis of frictional properties of modified fluoroplastic under the conditions of contact interaction with and without taking into account the lubrication of the mating surfaces is performed. Approximating functions have been selected to describe the dependence of the friction coefficient on the pressure acting on the contact section. The effect of the friction coefficient obtained experimentally on the contact deformation of the sliding layer is considered. Several qualitative and quantitative regularities have been established.
Geometrically Nonlinear Constitutive Equations of the Plastic Flow Theory in Terms of Asymmetric Stress and Strain Measures
Authors: Yants A Yu , Trusov P V
Published: July 2019

A formulation of the geometrically nonlinear plastic flow theory (PFT) based on asymmetric measures of stress and strain states is proposed. A main emphasis is placed on the physically reasonable decomposition of the deformation gradient into three components: elastic distortions, which determine stresses, an orthogonal tensor characterizing the quasi-rigid motion of a material and the plastic strain gradient. The quasi-rigid motion of the material is defined by introducing for a representative volume element a generalized lattice, which represents its symmetry elements. The hypoelastic anisotropic law is introduced in terms of the movable coordinate system associated with the material. The rate of plastic deformations is determined by the associated law of plastic flow. As a result, the closed system of constitutive equations of the geometrically nonlinear PFT of is obtained.