bluuebunny/crossref_metadata_2025 huggingface dataset:
A metal-semiconductor transition in helical graphene nanoribbon
Authors: Liu Zhong-Pei , Guo Yan-Dong , Yan Xiao-Hong , Zeng Hong-Li , Mou Xin-Yi , Wang Zi-Ru , Wang Jin-Jie
Published: October 2019

Inspired by recent progress of experimental fabrication of partial structure of the helical graphenes, we construct helical graphene nanoribbons and study the electronic structure and transport properties of them, through first-principles calculations. It is found that a metal-semiconductor transition occurs when the pitch of the configuration changes, and the whole transition process can be divided into three regimes, i.e., metallic, fast changing bandgap, and slowly changing bandgap ones. Further analysis shows that, interlayer transmission, interlayer interaction (bilayer graphenelike state) and intralayer interaction are the mechanisms behind, respectively. Moreover, such a transition and corresponding mechanisms show good robustness to the size of the helical graphene nanoribbons, suggesting great application potential. As the systems are pure-carbon and graphene-based ones, as well as an adjustable and reversible bandgap, such configurations might be quite useful in future nanodevices.
Mapping phonon modes from reduced-dimensional to bulk systems
Authors: Kim Hyun-Young , Parrish Kevin D. , McGaughey Alan J. H.
Published: October 2019

A lattice-dynamics-based algorithm for mapping the true phonon modes of a film, defined by a two-dimensional (2D) Brillouin zone, to the modes of the corresponding bulk material, defined by a three-dimensional (3D) Brillouin zone, is proposed. The mapping allows for an assessment of the common assumption that film phonon modes have the same harmonic properties as the corresponding bulk phonon modes. The algorithm is based on normal mode decomposition and is inspired by the observation that the atomic trajectories generated by the 2D eigenvectors lead to standing-wave-like behaviors in the cross-plane direction. This behavior enables an unfolding scheme that does not require an assumption of cross-plane periodicity, as used in previous approaches for mapping phonon modes. The algorithm is applied to films between two and ten unit cells thick built from Lennard-Jones (LJ) argon, whose bulk is isotropic, and graphene, whose bulk (graphite) is anisotropic. For LJ argon, the density of states deviates from that of the bulk as the film gets thinner due to phonon frequencies that shift to lower values. This shift is a result of transverse branch splitting due to the film’s anisotropy and the emergence of a quadratic acoustic branch. As such, while the mapping algorithm works well for the thicker LJ argon films, it does not perform as well for the thinner films as there is a weaker correspondence between the 2D and 3D modes. For graphene, the density of states of even the thinnest films closely matches that of graphite due to the inherent anisotropy, except for a small shift at low frequencies. As a result, the mapping algorithm works well for all thicknesses of the graphene films, indicating a strong correspondence between the 2D and 3D modes.
Characterizing spacecraft potential effects on measured particle trajectories
Authors: Barrie A. C. , Cipriani F. , Escoubet C. P. , Toledo-Redondo S. , Nakamura R. , Torkar K. , Sternovsky Z. , Elkington S. , Gershman D. , Giles B. , Schiff C.
Published: October 2019

As spacecraft does not have an independent method to conduct charge to ground, it naturally accumulates charge due to interactions with the ambient plasma and surface emission. This charge produces an electric field surrounding the spacecraft, which takes the form of a plasma sheath. Charged particles traveling through this sheath are altered in both energy and direction, thus affecting derived scientific quantities. While this effect has been known since the advent of space based particle instruments, this work represents the first time that an in situ characterization study of this effect has been possible. The Fast Plasma Investigation, of the Magnetospheric Multiscale mission, obtains near simultaneous measurements of phase space, via particle counts from 512 look directions and 32 energies. These new data allow the relative effects of the plasma sheath to be explored at a high time and spatial resolution. This work presents a method by which these measurements are used to study a ground model that traces the migration of particles through the sheath and estimates the error in measured velocity. This approach, performed statistically, leads to an estimation of uncertainty in particle count distributions for a given location in phase space and characterization of the redistribution of counts within a skymap due to sheath effects.
Incomplete ionization in aluminum-doped 4H-silicon carbide
Authors: Darmody C. , Goldsman N.
Published: October 2019

In this work, we investigate the degree of incomplete ionization of Al doped 4H-SiC. In particular, we perform analysis on a comprehensive list of published measurements of ionization energy, resistivity, and Hall mobility for varying Al concentration. These data are used to construct two separate models with which we calculate the fraction of mobile holes to dopant atoms p/NA. First, we create a physics-based theoretical model which includes the effects of doping-dependent ionization energy, quantum-mechanical spreading of the acceptor density of states, and density of states smearing due to disorder effects. Our second model is derived mainly from experimental Hall and resistivity data, and we use the results of this calculation to verify our results from the theoretical model. We find good agreement between the two approaches which gives confidence to our resulting p/NA calculations. At doping above 1020cm−3, we observe an increase in the p/NA ratio which is likely due to the onset of a parallel impurity conduction mechanism which does not require dopant ionization. We also provide an easily evaluated expression which predicts p/NA at higher temperatures based on our full theoretical model.
Energy dependent structure of Xe ion tracks in YBCO and the effect on the superconductive properties in magnetic fields
Authors: Suvorova Elena I. , Degtyarenko Pavel N. , Karateev Igor A. , Ovcharov Alexey V. , Vasiliev Alexander L. , Skuratov Vladimir A. , Buffat Philippe A.
Published: October 2019

The morphology and structure of damaged regions (tracks) produced by swift heavy 167, 77, and 46 MeV 132Xe23+ ions in YBCO-based second generation industrial high temperature superconductors wires (2G HTS) were studied using transmission electron microscopy. It was shown that ions produce tracks aligned along the ion trajectory but of morphology depending on their energy: continuous, nearly continuous, or discontinuous tracks like prolate ellipsoids of 10–15 nm in length and spheroids of 5 nm in diameter. The damaged regions of about 5 nm in diameter contain an amorphous material with a lower density compared to the pristine YBCO. The material density drops from 6300 kg m−3 for YBCO matrix to 3600 kg m−3 inside the tracks. Barium enrichment was found in the vicinity of the track at a distance of about 10 nm from the center of the defect. Ion damage tracks with different morphologies showed different effectivenesses as pinning centers. Tracks composed of discontinuous pinning centers—spheroids of about 5 nm in diameter—bring the best enhancement of the critical current density. It occurs for the lowest ion energy (46 MeV) in the range of energy loss of 8.9 keV/nm–4.7 keV/nm for Xe ions. The samples showed highest critical current densities of 56 MA/cm2 (4.2 K) and 3 MA/cm2 (77 K) in self-field, while in magnetic fields of 8 T, the values of 17 MA/cm2 (4.2 K) and 1.6 MA/cm2 (77 K) were achieved. The reduction of the superconducting volume corresponding to the amorphous radiation defects did not exceed 4% from the total sample volume.
Structural and magnetic properties of Cu-doped ZnO epitaxial films at the coalescence limit—A superparamagnetic CuO-ZnO nanocomposite
Authors: Ney V. , Venkataraman V. , Wilhelm F. , Rogalev A. , Ney A.
Published: October 2019

A series of Cu-doped ZnO epitaxial films has been grown on sapphire substrates to investigate the possibilities of preparing a doped magnetic oxide at the coalescence limit. The growth was performed using reactive magnetron sputtering by varying the oxygen partial pressure to tune the incorporation of the Cu dopant and the resulting valence state. At low oxygen pressures, metallic Cu precipitates are formed, while at high oxygen partial pressures, the formation of CuO as a secondary phase could be evidenced. In-between, only a small fraction of the Cu can be substitutionally incorporated into the ZnO host matrix. The resulting magnetic properties are predominantly paramagnetic. However, the formation of the secondary CuO phase is accompanied by a small field imprinted magnetic component, which suggests that the CuO secondary phase consists of small and, thus, magnetically unblocked nanoprecipitates which are dispersed in the ZnO host matrix.
Mechanotransduction studies improved by revealing solvent effect on type I collagen
Authors: Gasparini Allison
Published: October 2019

Researchers find solvent composition and pH level have huge impact on efficiency of collagen I coating when used in mechanotransduction.
4WD Driving Skills
Authors: Widman Vic
Published: October 2019

An essential guide to safe and responsible four-wheel driving.
Modern four-wheel drive vehicles are powerful and sophisticated machines, able to travel almost anywhere. Given their growing popularity with recreational drivers, there is an even more pressing need for adequate training. Even on sealed roads these vehicles require a different set of driving skills; off-road, the demands are many times greater.
This second edition of the bestselling 4WD Driving Skills complements nationally recognised training courses and has been fully revised to include updated vehicle terminology, technology and recovery techniques. It explains the essential skills of four-wheel driving for every type of on- and off-road terrain, how to approach challenging situations, and what to do if things go wrong. It is a valuable reference for all four-wheel drive enthusiasts.
The Fats of Life: Using Computational Chemistry to Characterise the Eukaryotic Cell Membrane
Authors: Wilson Katie A. , Wang Lily , MacDermott-Opeskin Hugo , O'Mara Megan L.
Published: October 2019

Our current knowledge of the structural dynamics and complexity of lipid bilayers is still developing. Computational techniques, especially molecular dynamics simulations, have increased our understanding significantly as they allow us to model functions that cannot currently be experimentally resolved. Here we review available computational tools and techniques, the role of the major lipid species, insights gained into lipid bilayer structure and function from molecular dynamics simulations, and recent progress towards the computational modelling of the physiological complexity of eukaryotic lipid bilayers.
Quantitative determination of cellular [Na+] by fluorescence lifetime imaging with CoroNaGreen
Authors: Meyer Jan , Untiet Verena , Fahlke Christoph , Gensch Thomas , Rose Christine R.
Published: October 2019

Fluorescence lifetime imaging microscopy (FLIM) with fluorescent ion sensors enables the measurement of ion concentrations based on the detection of photon emission events after brief excitation with a pulsed laser source. In contrast to intensity-based imaging, it is independent of dye concentration, photobleaching, or focus drift and has thus been successfully employed for quantitative analysis of, e.g., calcium levels in different cell types and cellular microdomains. Here, we tested the suitability of CoroNaGreen for FLIM-based determination of sodium concentration ([Na+]) inside cells. In vitro measurements confirmed that fluorescence lifetimes of CoroNaGreen (CoroNaFL) increased with increasing [Na+]. Moreover, CoroNaFL was largely independent of changes in potassium concentration or viscosity. Changes in pH slightly affected FL in the acidic range (pH ≤ 5.5). For intracellular determination of [Na+], HEK293T cells were loaded with the membrane-permeable form of CoroNaGreen. Fluorescence decay curves of CoroNaGreen, derived from time-correlated single-photon counting, were approximated by a bi-exponential decay. In situ calibrations revealed a sigmoidal dependence of CoroNaFL on [Na+] between 0 and 150 mM, exhibiting an apparent Kd of ∼80 mM. Based on these calibrations, a [Na+] of 17.6 mM was determined in the cytosol. Cellular nuclei showed a significantly lower [Na+] of 13.0 mM, whereas [Na+] in perinuclear regions was significantly higher (26.5 mM). Metabolic inhibition or blocking the Na+/K+-ATPase by removal of extracellular K+ caused significant [Na+] increases in all cellular subcompartments. Using an alternative approach for data analysis (“Ratio FLIM”) increased the temporal resolution and revealed a sequential response to K+ removal, with cytosolic [Na+] increasing first, followed by the nucleus and finally the perinuclear regions. Taken together, our results show that CoroNaGreen is suitable for dynamic, FLIM-based determination of intracellular [Na+]. This approach thus represents a valuable tool for quantitative determination of [Na+] and changes thereof in different subcellular compartments.
Bipartite nonlocality with a many-body system
Authors: Oudot Enky , Bancal Jean-Daniel , Sekatski Pavel , Sangouard Nicolas
Published: October 2019

We consider a bipartite scenario where two parties hold ensembles of 1/2-spins which can only be measured collectively. We give numerical arguments supporting the conjecture that in this scenario no Bell inequality can be violated for arbitrary numbers of spins if only first order moment observables are available. We then give a recipe to achieve a significant Bell violation with a split many-body system when this restriction is lifted. This highlights the strong requirements needed to detect bipartite quantum correlations in many-body systems device-independently.
A tunneling current measurement scheme to observe Majorana-zero-mode-induced crossed Andreev reflection
Authors: Fang Lei , Schmeltzer David , Zhu Jian-Xin , Saxena Avadh
Published: October 2019

We propose a scheme to observe the Majorana-zero-mode-induced crossed Andreev reflection by measuring tunneling current directly. In this scheme a metallic ring structure is utilized to separate electron and hole signals. Since tunneling electrons and holes have different propagating wave vectors, the conditions for them to be constructively coherent in the ring differ. We find that when the magnetic flux threading the ring varies, it is possible to observe adjacent positive and negative tunneling current peaks of about equal amplitudes.
Quantifying the interplay between genetic and epigenetic regulations in stem cell development
Authors: Zhang Yunbin , Liu Ning , Lin Wei , Li Chunhe
Published: October 2019

Waddington epigenetic landscape, as a classic metaphor, has been used to explain cellular development and differentiation. However, it remains challenging to quantify the epigenetic landscape. Especially, a key issue arises as what are the underlying mechanisms for the interplay between genetic and epigenetic regulations to govern cell fate decisions in development. Based on a developmental epigenetic model combining histone modifications and gene regulations, we studied state switching mechanisms of histone modifications for stem cell development, and uncovered corresponding epigenetic landscape. The topography of landscape provides a quantitative measure for the relative stability of different attractors or phenotypes. We showed that histone regulations facilitate the occurrence of intermediate states or multistability. From the epigenetic landscape of stem cell differentiation, we identified key cellular states characterized by attractors, including pluripotent stem cell state, differentiated state and intermediate states. We also quantified representative kinetic transition paths for differentiation, reprogramming and transdifferentiation, which agree well with previous experimental observations. Specifically, previous experiments indicate that transdifferentiation can go through a mixed, unspecific intermediate or progenitor-like state. By calculating the kinetic transition paths, our developmental epigenetic models are able to replicate all these three experimental results, and therefore provide theoretical explanations for these experimental observations. We propose that epigenetic regulations play critical roles on the kinetic transitions for differentiation, reprogramming and transdifferentiation, which also provide a source for the heterogeneity of gene expressions observed in developmental process. Our work provides new insights into the roles of epigenetic modifications on controlling gene expression and stem cell differentiation, and facilitates our mechanistic understanding for the cell fate determinations regarding the interplay between genetic and epigenetic regulations.
Probing relaxations of atomic-scale junctions in the Pauli repulsion range
Authors: Brand J , Néel N , Kröger J
Published: October 2019

Clean metal as well as C60-terminated tips of an atomic force microscope probe the interaction with C60 molecules adsorbed on Cu(111) and Pb(111). The force measurements unveil a monotonic shift of the point of maximum attraction with the bias voltage. The conventional superposition of long-range van der Waals and electrostatic forces with short-range Pauli repulsion does not reproduce the shift. By phenomenologically including bias-dependent relaxations of the electrode geometry in the analytical expression for the short-range force the experimental data can qualitatively be described.
Comparing the dynamics of periodically forced lasers and neurons
Authors: Tiana-Alsina Jordi , Quintero-Quiroz Carlos , Masoller Cristina
Published: October 2019

Neuromorphic photonics is a new paradigm for ultra-fast neuro-inspired optical computing that can revolutionize information processing and artificial intelligence systems. To implement practical photonic neural networks is crucial to identify low-cost energy-efficient laser systems that can mimic neuronal activity. Here we study experimentally the spiking dynamics of a semiconductor laser with optical feedback under periodic modulation of the pump current, and compare with the dynamics of a neuron that is simulated with the stochastic FitzHugh–Nagumo model, with an applied periodic signal whose waveform is the same as that used to modulate the laser current. Sinusoidal and pulse-down waveforms are tested. We find that the laser response and the neuronal response to the periodic forcing, quantified in terms of the variation of the spike rate with the amplitude and with the frequency of the forcing signal, is qualitatively similar. We also compare the laser and neuron dynamics using symbolic time series analysis. The characterization of the statistical properties of the relative timing of the spikes in terms of ordinal patterns unveils similarities, and also some differences. Our results indicate that semiconductor lasers with optical feedback can be used as low-cost, energy-efficient photonic neurons, the building blocks of all-optical signal processing systems; however, the length of the external cavity prevents optical feedback on the chip.
A new Lagrange-Galerkin scheme for solving fluid flow in porous media
Authors: Wijaya Imam , Kimura Masato , Notsu Hirofumi
Published: October 2019

We introduce a new Lagrange–Galerkin scheme for computing fluid flow through porous media. The method of volume averaging of the velocity and pressure deviation in the pore is employed to derive the macroscopic mass and momentum conservation in the porous medium in which this technique was established by Hsu and Cheng. We derive the Lagrange–Galerkin scheme by extending the idea of the method of characteristics to overcome the difficulty which comes from the non-homogeneous porosity. The numerical experiment are conducted to verify the performance of the new numerical scheme. The new numerical scheme shows a good agreement with the analytical solution and has 2
nd
order accuracy both in space and time.
3d seismic velocity structure imaging beneath Flores region using local earthquake tomography
Authors: Maneno R , Santosa B J
Published: October 2019

Flores is one of the seismically high activity zones of Indonesia region as a consequence of Indo-Australian plate subduction under the Eurasian plate. We investigate 3D seismic velocity structure beneath Flores region and the surrounding area as an effort to understand earthquake source mechanisms and subsurface geometry for the purpose of earthquake disaster mitigation. The study based on travel-time tomography using 223 earthquakes provided by webdc.eu catalog data which is recorded by up to 4 stations during period from January 2010 to March 2018. In the early data processing stages, a total of 1763 P-wave arrivals and 1763 S-wave arrivals were manually picked from 15 seismic stations around the Flores region using SeisGram2k70. 170 events with minumum error in VELEST used to derive a minimum 1D velocity model. The combination of Santosa & Haslinger and AK135 velocity model used as a reference velocity model to Flores region. Futhermore we applied Local Earthquake Tomography (LOTOS 12) to investigated 3D seismic velocity in order to describe anomalous distribution of P and S wave velocities beneath Flores Region. The results showed that Flores region is dominated by a negative seismic velocity anomaly and a high Vp / Vs ratio that is thought to be related to the fault area due to the Flores Thrust Zone in the north and west of Flores and the upward fault in east Flores. The southern part of Flores is dominated by positive anomalies and a low Vp / Vs ratio which is thought to be igneous and metamorphic layers with a low liquid saturation level. Insufficient data causes the resulting tomographic resolution to be poor.
First light curve analysis of eclipsing binary system ASAS 185542–0123.1
Authors: Jatmiko Agus T P , Yusuf M , Putra M
Published: October 2019

A very first light curve (LC) analysis of eclipsing binary ASAS 185542–0123.1 is presented. This star is part of our binary star survey project at Bosscha Observatory and also plays an important role as a testing ground for our new robotic telescope. LC of this star was constructed by using LEMON, a semi–automatic photometric pipeline written in Python. We managed to refine orbital period of this system and its time of primary minimum, hence we could update its ephemeris as Min I(HJD) = 2451964.551517 + 1.161607 × E. We also conducted a LC modeling with PHOEBE (PHysics Of Eclipsing BinariEs) software built on top of the widely used WD program. The photometry solutions are mass ratio q = 0.309 ± 0.026, orbital inclination i = 83.15 ± 0.42°, ratio of effective temperatures

T
2

T
1

=
0.972
±
0.008

, and surface potentials for primary and secondary component Ω1 = 4.08 ± 0.16 and Ω2 = 2.71 ± 0.10, respectively. In conclusion, this system is classified as detached eclipsing binary system which has almost similar temperatures between its primary and secondary component. From temperature solution estimation, we have preliminary conclusion that its primary and secondary component has a spectral type of G0/1V + G2/3V, respectively.
Tracing Stellar Close Encounters with Our Sun from GAIA DR2, LAMOST DR4, and RAVE DR5 Catalogues
Authors: Darma R , Hidayat W , Arifyanto M I
Published: October 2019

Our Sun is surrounded by the Oort Cloud (in radius 0.5 pc) which can be perturbed by various external factors. One of those is the stellar close encounter with our Sun. This kind of perturbation can induce the cometary showers in our Solar System. In this work, we attempt to make numerical simulations to trace the orbit of stars which close encounter with our Sun in the cases of Milky Way’s axisymmetric only and with non-axisymmetric potentials. We have 306 selected solar neighborhood stars from GAIA DR2, LAMOST DR4, and RAVE DR5 which have highly precise kinematics.

In this work, we find a few stars that have counter parameter (dm
) less than or equal to 2 pc in both of past and future close encounters with the Sun. We also find a few stars (ID 283, 290, 297, 298) even with dm
≤ 0.5 pc within their errors, for past close encounters at time tm
≥ 0.5 Myr ago. These stars should have perturbed the Oort Cloud’s stability long time ago. Furthermore, we find a few stars (ID 293, 299, 300) with dm
≤ 1 pc within their errors, at tm
> 0.6 Myr for future close encounters. Besides that,cadding non-axisymmetric component of Milky Way does not change the results. This suggests that the non-axisymmetric component of Milky Way potential has small effect in perturbing the orbital motion of stars for short timescale. That’s why the values of dm
are relatively similar within their errors, for both cases of the Milky Way potential.
Metals Content In Edible Gastropod From Blanakan Silvofishery Ponds
Authors: Artalina Desmita , Takarina Noverita Dian
Published: October 2019

Human activities contribute to waste and promote threats to water quality. Heavy metals contamination is one of the threats. High input of heavy metals on ponds will affect organism including gastropods. Mangrove snail (Telescopium telescopium) is one of the non-cultural biotas which is consumed by humans. This research aimed to determine metals content in mangrove snail flesh from Blanakan silvofishery ponds. Samples were conducted from three ponds using a purposive sampling technique in April 2018. Metals content were analyzed using Atomic Absorption Spectrophotometry. The Result showed that the highest Pb and Cu content was in pond 3 at 19,46 mg/kg and 27,52 mg/kg respectively and the highest Zn content was in pond 1 at 21,28 mg/kg. The Bioconcentration Factor (BCF) values ranged 0,05 – 4,57 showed that mangrove snail has a tendency to accumulate heavy metals. The bioconcentration values > 1 at Cu showed that mangrove snail can be used as bioindicator to control Cu pollution, especially in the mangrove ecosystem. One of the efforts to protect public health is to set a maximum limit of metal contamination in food that is suitable for consumption. The maximum limit of metal contamination in food is determined through a decree of the General Director of Drug and Food Control, an institution in Indonesia which is in charge of overseeing the circulation of drugs and food in accordance with the provisions of the legislation. Based on The National Agency of Drug and Food Control No. 03725/B/SK/VII/89, people must be more careful in consuming mangrove snail.
Chaotic Behaviour of Modified Hamiltonian Peyrard-Bishop-Dauxois Model on DNA System
Authors: Sutantyo Trengginas E P , Dwiputra D , Hidayat W , Zen Freddy P
Published: October 2019

DNA research has involved a variety of disciplines across fields, which work complementary and supportive by using the theory, model, and experiment. Physics provides a theoretical basis that can be used for experimentation, as well as developing new physical models. This physical model can explain the nonlinear dynamics of DNA. In this study, we modified Hamiltonian Peyrard-Bishop-Dauxois (PBD) model by adding the influence of the surrounding environment namely thermal bath, in the form of time-dependent thermal friction and stochastic white noise. Both are represented through the Nosé-Hoover-Langevin (NHL) thermostat. Formulations of equation motion are obtained using analytical methods, to be solved using numerical methods. We present the numerical calculations results in phase space images to show chaotic behaviour. Furthermore, we gain an increase in chaotic patterns along with the increase in temperature. In addition, we also obtain the relationship between the distance of the base pair with temperature, especially in the denaturation process.
Parameter Constrain of Nonminimal Derivative Coupling of Scalar Field Using Strong Energy Condition
Authors: Taufani M. R. , Suroso A. , Zen F. P.
Published: October 2019

The study aims to determine the constrain of the coupling parameter/xi of nonminimal derivative coupling theory (NMDC) of scalar field. The calculation of the parameter was build from the strong energy conditions combined to modified Einstein theory(i.e. the scalar filed act as the external source of gravity beside the ideal fluid). The violation of strong energy condition (SEC) indicate the atrracting gravity phenomenon. Then one can expecting two equations that consist of of energy density ρ and the momentum p, then one defined the deacceleration q to these equation. The present value of cosmological constant such as Hubble constant H, q, and scale factor a need to be put into the equations to determine the boundaries of the strong energ. The results show the coupling parameter must be ξ ≥ 1.2 × 1034
s
2 for the SEC to be valid in the theory.
Determination of Environmental Condition in Universitas Pelita Harapan Based on Radon Concentration Analysis
Authors: Cahyadi L , Pangaribuan J , Junita  , Saputra K V I
Published: October 2019

Radon Gas is the largest contributor to the annual effective dose received by humans, which is colorless, tasteless, and invisible to the eye. This gas is harmful and can cause lung cancer. Thus, we try to study the average concentration level of Radon Gas in 20 workspace rooms in two different buildings located at the same altitude that mostly made of different building materials. First are HRD workspace rooms in building A that are mostly partitioned and enclose with cemented walls and glasses. Second are FaST workspace rooms that are partitioned and enclose with gypsum. All of the rooms are equipped with air conditioner and lack air circulation. The concentration of radon gas is measured by a passive radon dosimeter equipped with a CR-39 detector. The detectors are placed in those 20 workspace rooms of Pelita Harapan University for 3 months. Radon gas levels obtained ranged from 37.95 ± 2.68Bq/m3 to 91.07 ± 6.44Bq/m3 with an average value of 58.39 ± 4.13Bq/m3. In average, concentration of Radon gas in offices at FaST is 67.543±4.775Bq/m3, which higher than average concentration of Radon gas offices at HRD that is 49.244±3.741Bq/m3. The higher concentration of Radon gas that is 91.07 ± 6.44Bq/m3 is found in room named FaST 1, which have lack air circulation, enclose in 4 sides with gypsum, and packed with boxes. The lowest concentration of Radon gas that is 37.95±2.68Bq/m3 is found in room named FaST 7, which enclose in 4 sides with glasses and contains only several tables and chairs. Yet, the measured concentration of Radon gas is still below the threshold recommended by the International Atomic Energy Agency (IAEA), which is 1000Bq/m3.
One-Dimensional Motion Analysis of a Cylinder with a Magnetic Dipole Inside an External Magnetic Field
Authors: Setiadi Bram Yohanes , Viridi Sparisoma
Published: October 2019

Electromagnetism has evolved from only a science into an inseparable part of our daily life, nowadays. One kind of benefit of it is the use of magnetic field as an energy source of any physical movements. A motion analysis system was designed and built in this experiment. It consists of a solenoid, two cylinders made from acrylic where magnet chips are inserted within them, and a rail track or container for the cylinders. The goal of this research is to observe and specify the types of motion produced by the cylinder as a response of external magnetic fields from the solenoid. The dependent variables include starting position and starting angle of the cylinder, the amount of magnet chips injected, and the voltage used to supply the solenoids. The motion is a rolling motion, consisting of translational and rotational motions. The rolling motion that we observed is divided into two types, pure and with slipping, while later is divided again into translational and rotational dominance.
Optical Characteristic Properties of Probiotic Drink Using Spectrophotometer UV/Vis and FTIR
Authors: Sitorus Rizqa , Herman  , Hendro
Published: October 2019

This research aims to qualitively observe the light absorbtion response from probiotic drink to several spectra of electromagnetic waves. This absorption response will later be related to physical properties of probiotic drink. The Observations in the infrared region used Bruker ATR Alpha FTIR Spectrometer while the observations in the UV and visible light region used Thermo Scientific Evolution 220 UV-Visible Spectrophotometer. The measuring time was done until there is a change in probiotic drink absorption. The measurement results obtained were in the form of the transmittance spectrum of the wavelength. Measurements in the infrared region showed some probiotic drink content such as protein at ~6123 nm, lactose at ∼9532 nm, and glucose at wave number ∼1100-800 cm−1. In the UV region, it is related to the reduction amount of protein while visible light region was associated with changes in the constituent particles of probiotic drink along with changes in pH. All observations refer to the literature. The results of this observation certainly do not represent all the contents of probiotic drink but this method can also be utilized for freshness detection of other similar drinks that contain milk.
Structural properties of bismuth ferrite synthesized by sol-gel method with variation of calcination temperature
Authors: Abdillah M N , Triyono D
Published: October 2019

The effect of calcination temperature (500°, 600° and 700°C) on structural properties of BiFeO3 synthesized by sol-gel method was studied. The structure of BiFeO3 sample was investigated by using X-ray diffraction (XRD), Raman scattering spectroscopy, Fourier Transform Infrared spectroscopy (FTIR), and supported by UV-Visible spectrophotometry (UV-Vis) analysis. The XRD analysis revealed the stability of single-phase hexagonal crystal structure with R3c space group in calcination condition of 700°C. The Raman spectroscopy observed the presence of Fe–O stretching which is also confirmed by FTIR analysis. UV-Vis measurement described the slightly increasing of gap energy as calcination temperature increase.
Detection of idden defects in low-k dielectrics by atomic force microscopy
Authors: Ovchinnikov I S , Vorotilov K A , Seregin D S , Yu Dalskaya G
Published: October 2019

A new nondestructive technique for detection of latent defects in the interlevel low-k dielectric using atomic-force microscopy in the PFQNM mode with a lateral resolution of 8 [nm] is proposed. It has been established that cavities embedded in the dielectric structure influence the magnitude of the detected deformation (from 1.1 to 3.5 [nm]) and the Young’s modulus (from 5.5 to 1.5 [GPa]). It is shown that this method allows to detect defects in the structure of a low-k dielectric located at a depth of 50 [nm] under the surface.
Detection of inhomogeneities in biological tissues using radio wave tomography
Authors: Eremeev A I , Shipilov S E
Published: October 2019

The paper shows the method for detecting and mapping inhomogeneities in biological tissues with using the radio-wave tomosynthesis. The method of radio-wave tomosynthesis allows calculating a three-dimensional distribution of permittivity in a studying space. The distribution gives the opportunity to determine tissue inhomogeneities, also their location and size. This method is suitable for dynamic observation of changes in education size due to harmlessness to humans. Unlike X-ray methods, for which regular doses of ionizing radiation contraindicated. Therefore, the development of non-invasive methods for the search for inhomogeneities in biological media based on radio-wave sounding is very relevant.
Development of a model fiber-optic sensor of the external action on the basis of diffraction gratings with variable parameters of the system
Authors: Sh Madi P , Kalytka V A , Alkina A D , Nurmaganbetova M T
Published: October 2019

Physical and mathematical model of the control system parameters of the optical signal using the sensor of the external action on the basis of a diffraction grating with variable characteristics (the lattice period; the width of the transparent strip (zone); width of the absorbing strip (zone)) are developing. A mathematical model of the diffraction grating is constructed on the basis of equations to calculate the resulting intensity and amplitude of the interference light passing through the grating. For the model of a lattice with a round hole, equations containing special functions of the Bessel function type, calculated numerically by calculating convergent infinite power series and integrals which are not calculated analytically, are proposed. The degree of accuracy of the developed model is determined by the severity of the underlying fundamental equations of theoretical and mathematical physics.
Method of calculation of diagnostic signs based on the results of densitometry of spherical lung formations
Authors: Molodkin I V , Yakunin A G , Shayduk A M
Published: October 2019

The article presents a method for obtaining quantitative signs of pulmonary pathology, based on the analysis of medical imaging computed tomography. These signs may be suitable for the differential diagnosis of spherical lung formations. In particular, the possibility of diagnosing cancer and pulmonary tuberculosis was investigated by quantitative statistical characteristics of images of spherical lung formations. Two of these characteristics (the densitometric value and its standard deviation) can be called classical, since modern basic software of computer tomographs can easily calculate them. In addition, characteristics were considered, for which it is necessary to carry out additional calculations using fractal analysis. The article presents the results of a study of the relationship of statistical and fractal characteristics of a tomographic image with the type of pathology in the lungs. The results of a statistical analysis of the fractal dimension of the region of interest and its related parameters are presented, and signs are found suitable for the diagnosis of pulmonary pathologies.
Research of high power output ultrasonic generator operation features
Authors: Muksunov T R , Yu Kuzmenko I , Ya Suhanov D
Published: October 2019

Harmonic signal of a given frequency and amplitude is required for ultrasonic instrument operation.At a power output of 200 W there is a need to refine the scheme because of negative effects which could be neglected at lower power.This article shows an introduction of changes to the transformer switching circuit generating high power ultrasonic signal.
Classification of Arabica Java Coffee Beans Based on Their Origin using NIR Spectroscopy
Authors: Kurniawan F , Budiastra I W , Sutrisno  , Widyotomo S
Published: October 2019

The NIR spectroscopy for characterization and classification of intact Java arabica coffee beans based on their origin is proposed. Commonly, NIR spectroscopy is used to determine composition of agricultural products including coffee. Three kinds of Java arabica coffee beans namely Arabica Java Preanger, Arabica Bondowoso and Arabica Malang were used in this research. Three hundred samples, each consisted of 100 g coffee beans were prepared. The coffee beans of 100 g were placed in petri dish and the light reflectances of intact coffee beans were measured by FT-NIR spectrometer at the wavelength of 1000-2500 nm. After reflectance measurement, the samples were subjected to composition analysis using proximate and Liquid Chromatography Mass Spectrometry. The reflectance and absorbance spectra were processed by five spectra data pretreatments (smoothing, first derivative, second derivative, Standard Normal Variate (SNV), Multiple Scatter Correction (MSC)) and then Principle Component Analysis (PCA) were carried out. Discriminant analysis (DA) of Principle Components were developed to classify coffee beans based on their origin. The results show that the spectra data treatments of SNV and MSC of reflectance spectra and PC analysis using PC1 and PC2 gave the best results for discriminating three kinds of coffee beans. The DA of three principle components of reflectance data processed by SNV and MSC could classify arabica coffee beans accurately (100%). This results shows that NIR spectroscopy can be used as a nondestructive method to classify arabica coffee beans based on their origin.
Minimally Processed for Cassava Browning Inhibition by Ascorbic Acid and Oxygen Absorbent
Authors: Winanti D D T , Darmawati E , Syarief R
Published: October 2019

The objective of this study was to examine the use of ascorbic acid and oxygen absorbent as anti browning agent for minimally processed cassava. The solution of 0% and 1% (w/v) ascorbic acid combined with packaging treatment by adding oxygen absorbent (+OA) and without oxygen absorbent (-OA) were use as anti browning system. Peeled cassava was dipped in the solutions for 30 minutes then packed into polyethylene plastic with packaging treatment and stored at 5°C. The results showed that dipping in 1% ascorbic acid solutions and oxygen absorbent packaging treatment could inhibit oxidation of polyphenol oxidase (PPO) of minimally processed cassava indicated by lower Browning Index.
The Volatile Components and Rice Quality of Three Indonesian Aromatics Local Paddy
Authors: Indrasari S D , Purwaningsih  , Jumali  , Handoko D D , Kusbiantoro B
Published: October 2019

The purpose of this research was to study the post-harvest analysis of local aromatic rice variety of AnakDaro, CicihMerah, and Mandoti covering the volatile component, physical and milling quality, and the physicochemical properties of rice. The research materials were obtained from local farmer in West Sumatera, South Sulawesi, and Bali. The analysis was conducted at the Rice Quality Laboratory at Indonesian Center for Rice Research (ICRR), Sukamandi, West Java. The results indicated that AnakDaro was extracted with Likens- Nickerson had a 2-acetyl-1-pyrroline amount (13.79 ppb) higher than that of Mandoti and CicihMerah. The extraction technique with Likens Nickerson has the best recovery compared to SPME (Solid Phase Microextraction) and maceration. In general there are differences in physical quality of grain and rice, milled quality and rice protein content of AnakDaro, Mandoti and CicihMerah. AnakDaro had high amylose content and hard cooked rice texture in cold conditions. CicihMerah had high amylose content with soft cooked rice texture in cold conditions. Mandoti had a very low amylose content with a very soft cooked rice texture in cold conditions. The characteristic of gelatinization temperature of Anak Daro and CicihMerah were high (> 74°C) while Mandoti was moderate (70-74°C).
Effect of Fermentation using Lactobacillus casei on the Physicochemical and Functional Properties of Sorghum Flour
Authors: Adiandri R S , Hidayah N
Published: October 2019

Sorghum is one of the high carbohydrate food sources that is still underutilized for processed food products due to its anti-nutritional content and functional properties. Fermentation is one of the processes that can reduce anti-nutritional content and improve the functional properties of sorghum flour. The purpose of this study was to determine the effect of Lactobacillus casei fermentation on the physicochemical and functional properties of sorghum flour. Sorghum used in this study was a local variety of KD-4 from Lamongan Dictrict, East Java. The experimental design used was Completely Randomized Design with two factors and three replication. The first factor was the concentration of bacteria in soaking water (0.05%; 0.10%; 0.15%, and 0.20% of the volume of water) and the second factor was the fermentation period (4, 8 and 12 hours). The results showed that concentration of bacteria and fermentation period generally affected the physicochemical and functional properties of sorghum flour. Increasing concentrations of bacteria and fermentation period tended to decrease tannin content, starch, amylopectin, and water and oil absorption but increased the value of whiteness, dietary fiber, amylose, and viscosity of sorghum flour.
The Effect of 1-Methylcyclopropene Treatment on Shallot Physiological Process and Qeight Loss
Authors: Kailaku S I , Broto W , Iriani E S , Diputra A S , Nuraeni F
Published: October 2019

Fresh-handling treatment using 1- Methylcyclopropene (1-MCP) has been proven effective in controlling respiration process of various horticultural commodities, helping to extend shelf-life for storage and transportation purpose. The effect of 1 -MCP treatment on shallot (A llium ascalonicum L. ) had yet been studied. It was expected to delay maturity, prevent negative effects of ethylene, and inhibit senescence by blocking ethylene receptor. The objective of this research was to study the effects of 1-MCP on the physiological process and weight loss of shallot. The research was preceded by the determination of 1 -MCP dosage, i.e. 0.5, 1, 1.5, 2, and 2.5 g. The best dosage was then used in the 1-MCP treatment on shallot. The duration of treatment was 0, 6, 18, 30, and 42 hours. Observation of physiological process was done to respiration rate (CO2) and ethylene production rate. Weight loss was also observed. The best dosage of 1-MCP was 2.5g with the content of 437.78 ppm. On the main experiment, 18 hours of treatment had the lowest but statistically the same respiration rate compared to other duration, and statistically different with the shallot without treatment. For ethylene production rate, 18 hours of treatment had the best effect and statistically different with the ones without treatment. Shallot with different treatments also showed insignificant different on weight loss, but were significantly different with shallot without treatment. Without treatment, the quality of shallot was dropped after 70 days of storage, while all the quality of treated shallot was maintained up to 84 days. It was concluded that 1 -MCP treatment was effective in controlling respiration rate and ethylene production rate. However, different duration of 1-MCP treatment had not showed different effects on shallot physiological process and weight loss.
Development of Local Food Biodiversity of Nata De Taro from Talas Beneng (Xanthosoma undipes k. koch.)
Authors: Hakiki D N , Rostianti T , Nasir  , Nursuciyoni
Published: October 2019

This research aimed to produce and formulate nata from Talas Beneng with different concentration ofAcetobacter xylinum. The raw material of talas beneng extract to starch then its residual water boiled, added 5% sucrose, 2% acetate acid and 1% ZA. Then it cooled until 25 °C, added Acetobacter xylinum, and fermented for 13 days. The concentration of Acetobacter xylinum addition with four levels namely 10%, 15%, 20 % and 25%. The parameters were physical analysis (yield,thickness, and hardness), chemical (crude fiber), and organoleptic (appearance, texture, flavor, and taste). The results showed that the addition of 25% concentration of Acetobacter xylinum was the highest yield and thickness as 30.98%, and 9.55 mm, then it has crude fiber 4.89% and hardness 0.1 mm/g.s. For organoleptic evaluation, the addition of 25% concentration of Acetobacter xylinum showed appearance, flavor, texture, and taste higher than others treatment.