bluuebunny/crossref_metadata_2025 huggingface dataset:
First-principles insights into mechanical, optoelectronic, and thermo-physical properties of transition metal dichalcogenides ZrX2 (X = S, Se, and Te)
Authors: Mahamudujjaman Md. , Afzal Md. Asif , Islam R. S. , Naqib S. H.
Published: February 2022

Transition metal dichalcogenides (TMDCs) belong to technologically important compounds. We have explored the structural, elastic, bonding, optoelectronic, and some thermo-physical properties of ZrX2 (X = S, Se, and Te) TMDCs in detail via the ab initio technique in this work. Elastic anisotropy indices, atomic bonding character, optoelectronic properties, and thermo-physical parameters, including melting temperature and minimum phonon thermal conductivity, are investigated for the first time. All the TMDCs under investigation possess significant elastic anisotropy and layered structural features. ZrX2 (X = S, Se, and Te) compounds are fairly machinable, and ZrS2 and ZrSe2 are moderately hard. ZrTe2, on the other hand, is significantly softer. Both covalent and ionic bondings contribute in the crystals. Electronic band structure calculations display semiconducting behavior for ZrS2 and ZrSe2 and metallic behavior for ZrTe2. Energy dependent optoelectronic parameters exhibit good correspondence with the underlying electronic energy density of state features. ZrX2 (X = S, Se, and Te) compounds absorb ultraviolet radiation effectively. The reflectivity spectrum, R(ω), remains over 50% in the energy range from 0 to ∼20 eV for ZrTe2. Therefore, this TMDC has a wide band and nonselective high reflectivity and can be used as an efficient reflector to reduce solar heating. The Debye temperature, melting point, and minimum phonon thermal conductivity of the compounds under study are low and show excellent correspondence with each other and also with the theoretically predicted elastic and bonding characteristics.
Epitaxial growth and thermoelectric properties of Mg3Bi2 thin films deposited by magnetron sputtering
Authors: Sadowski Grzegorz , Zhu Yongbin , Shu Rui , Feng Tao , le Febvrier Arnaud , Music Denis , Liu Weishu , Eklund Per
Published: February 2022

Mg3Sb2-based thermoelectric materials attract attention for applications near room temperature. Here, Mg-Bi films were synthesized using magnetron sputtering at deposition temperatures from room temperature to 400 °C. Single-phase Mg3Bi2 thin films were grown on c-plane-oriented sapphire and Si(100) substrates at a low deposition temperature of 200 °C. The Mg3Bi2 films grew epitaxially on c-sapphire and fiber-textured on Si(100). The orientation relationships for the Mg3Bi2 film with respect to the c-sapphire substrate are (0001) Mg3Bi2‖(0001) Al2O3 and [112¯0] Mg3Bi2‖[112¯0] Al2O3. The observed epitaxy is consistent with the relatively high work of separation, calculated by the density functional theory, of 6.92 J m−2 for the Mg3Bi2 (0001)/Al2O3 (0001) interface. Mg3Bi2 films exhibited an in-plane electrical resistivity of 34 μΩ m and a Seebeck coefficient of +82.5 μV K−1, yielding a thermoelectric power factor of 200 μW m−1 K−2 near room temperature.
A neural network enhanced weighted essentially non-oscillatory method for nonlinear degenerate parabolic equations
Authors: Kossaczká T. , Ehrhardt M. , Günther M.
Published: February 2022

In this paper, a new modification of the weighted essentially non-oscillatory (WENO) method for solving nonlinear degenerate parabolic equations is developed using deep learning techniques. To this end, the smoothing indicators of an existing WENO algorithm, which are responsible for measuring the discontinuity of a numerical solution, are modified. This is done in such a way that the consistency and convergence of our new WENO-DS (deep smoothness) method is preserved and can be theoretically proved. A convolutional neural network (CNN) is used and a novel and effective training procedure is presented. Furthermore, it is shown that the WENO-DS method can be easily applied to additional dimensions without the need to retrain the CNN. Our results are presented using benchmark examples of nonlinear degenerate parabolic equations, such as the equation of a porous medium with the Barenblatt solution, the Buckley–Leverett equation, and their extensions in two-dimensional space. It is shown that in our experiments, the new method outperforms the standard WENO method, reliably handles sharp interfaces, and provides good resolution of discontinuities.
Dispersion of a fluid plume during radial injection in an aquifer
Authors: Hyatt Benjamin W. A. , Leonenko Yuri
Published: February 2022

This study outlines a model for radial injected fluid flow with mechanical dispersion in a vertically confined porous aquifer. Existing studies have investigated fully segregated fluid flows in this setting, where the injected fluid and resident fluid form a propagating sharp interface. The present study uses the geometry of these sharp interfaces as a basis for the velocity field to take into account dispersion and buoyancy/viscosity effects. By differentiating the radial position of the sharp interface with respect to time, a time dependent radial velocity field governing the flow is obtained. Evaluating this radial velocity at the moment the original interface were to intersect a given position gives a velocity field that is a function of the position coordinates inside the aquifer. Using this velocity field, the fluids saturation profile resulting from mechanical dispersion can be found analytically. It is shown that the concentration of the injected fluid smoothly decays around the position of the corresponding sharp interface, allowing for the injected fluid to be present in detectable quantities beyond the extent of these solutions. This concentration spread should be considered in defining outer boundaries on fluids in injection well projects such as carbon sequestration or groundwater applications.
Numerical simulation of similarities between rotating detonation and high-frequency combustion instability under two mixing schemes
Authors: Fan Liangzhong , Shi Qiang , Lin Wei , Tong Yiheng , Sun Jian , Nie Wansheng
Published: February 2022

This paper presents an experimental study on rotating detonations in a hollow combustor with the slit-orifice nozzle. The experimental results reveal that the propagation speed of detonation waves increases with the rise of mass flow rates and is greater than the Chapman–Jouguet detonation speed (VC−J). Furthermore, numerical simulations of rotating detonation in a non-premixed three-dimensional cylindrical combustor have been conducted based on a multispecies reacting code. The influence of two mixing schemes—that is, slit-orifice and coaxial injector—on detonation waves are studied to determine whether the characteristics of detonation waves tend toward high-frequency combustion instability due to changes in the mixing scheme. It is found that the slit-orifice scheme’s detonation speed, pressure, and temperature are significantly higher than those of the coaxial injector scheme. In particular, the detonation speed of the former reaches 124% of the VC−J, while that of the latter is only 80.5% of the theoretical value. The numerical results reveal that the low-speed detonation is caused by the deterioration of the hydrogen (H2)/air mixing conditions. Moreover, the flow-field structures of two mixing schemes were comparable, both containing transverse detonation waves, oblique shocks, contact surfaces, and wedge-shaped reactant regions. Furthermore, the Rayleigh index analysis showed that the unsteady heat release was in phase with the pressure fluctuations, amplifying the pressure. Therefore, it is suggested that high-frequency combustion instability may be a manifestation of rotating detonation waves under poor mixing conditions.
Yb-doped Y–Al–O thin films with a self-organized columnar structure and their anti-Stokes photoluminescence properties
Authors: Nakayama Y. , Nakagawa N. , Matsuo Y. , Kaizu T. , Harada Y. , Ishihara T. , Kita T.
Published: February 2022

We fabricated ytterbium-doped yttrium aluminum oxide (Yb:Y–Al–O) thin films by radio-frequency magnetron sputtering and evaluated their crystallinity and anti-Stokes photoluminescence (PL) properties for optical refrigeration. The Yb:Y–Al–O films that were grown on c-sapphire substrates had better transparency than the films deposited on fused-quartz substrates. The better transparency is considered to be a result of the smaller mismatch between the thermal expansion coefficients of Yb:Y–Al–O and c-sapphire. We found that the thin films on the c-sapphire substrates consist of densely packed sub-micron columnar crystals that are aligned perpendicular to the substrate. In these films, we confirmed the existence of perovskite, garnet, and monoclinic phases despite using a single-phase sputtering target. The excitation wavelength dependence of anti-Stokes PL is used to investigate the energy transfer process between trivalent Yb ions in neighboring columnar crystals. The data indicate that the resonant energy transfer from Yb3+ ions at a specific seven-coordinated site of the monoclinic phase to Yb3+ ions in neighboring columnar crystals is faster than the radiative relaxation at the energy-donor site.
Multidimensional stochastic dissipative quantum dynamics using a Lindblad operator
Authors: Mandal Souvik , Gatti Fabien , Bindech Oussama , Marquardt Roberto , Tremblay Jean-Christophe
Published: February 2022

In this paper, multidimensional dissipative quantum dynamics is studied within a system–bath approach in the Markovian regime using a model Lindblad operator. We report on the implementation of a Monte Carlo wave packet algorithm in the Heidelberg version of the Multi-Configuration Time-Dependent Hartree (MCTDH) program package, which is henceforth extended to treat stochastic dissipative dynamics. The Lindblad operator is represented as a sum of products of one-dimensional operators. The new form of the operator is not restricted to the MCTDH formalism and could be used with other multidimensional quantum dynamical methods. As a benchmark system, a two-dimensional coupled oscillators model representing the internal stretch and the surface–molecule distance in the O2/Pt(111) system coupled to a Markovian bath of electron–hole-pairs is used. The simulations reveal the interplay between coherent intramolecular coupling due to anharmonic terms in the potential and incoherent relaxation due to coupling to an environment. It is found that thermalization of the system can be approximately achieved when the intramolecular coupling is weak.
Coupling mesoscale transport to catalytic surface reactions in a hybrid model
Authors: Fan Rong , Habibi Parsa , Padding Johan T. , Hartkamp Remco
Published: February 2022

In heterogeneous catalysis, reactivity and selectivity are not only influenced by chemical processes occurring on catalytic surfaces but also by physical transport phenomena in the bulk fluid and fluid near the reactive surfaces. Because these processes take place at a large range of time and length scales, it is a challenge to model catalytic reactors, especially when dealing with complex surface reactions that cannot be reduced to simple mean-field boundary conditions. As a particle-based mesoscale method, Stochastic Rotation Dynamics (SRD) is well suited for studying problems that include both microscale effects on surfaces and transport phenomena in fluids. In this work, we demonstrate how to simulate heterogeneous catalytic reactors by coupling an SRD fluid with a catalytic surface on which complex surface reactions are explicitly modeled. We provide a theoretical background for modeling different stages of heterogeneous surface reactions. After validating the simulation method for surface reactions with mean-field assumptions, we apply the method to non-mean-field reactions in which surface species interact with each other through a Monte Carlo scheme, leading to island formation on the catalytic surface. We show the potential of the method by simulating a more complex three-step reaction mechanism with reactant dissociation.
Cryo-ET of
Toxoplasma
parasites gives subnanometer insight into tubulin-based structures
Authors: Sun Stella Y. , Segev-Zarko Li-av , Chen Muyuan , Pintilie Grigore D. , Schmid Michael F. , Ludtke Steven J. , Boothroyd John C. , Chiu Wah
Published: February 2022

Significance

Tubulin polymers are essential for a variety of cellular functions. Using cryo-ET, we reveal the 3D organization of the apical complex in
Toxoplasma gondii
, an intracellular eukaryote with tubulin-based structures, including an apical “conoid” involved in host cell invasion. Our development of an advanced subtomogram averaging protocol for filamentous structures enabled us to accurately assign tubulins in cellular context. At the subnanometer resolution achieved, tubulins were confirmed to assemble into two major forms: canonical subpellicular microtubules (SPMTs) and noncanonical conoid fibrils (CFs). The data further revealed associated proteins in both structures, a dominant orientation of SPMTs, and a unique patterning of the CFs. This work demonstrates an approach that can be used to determine cellular filamentous structures at multiscale resolutions.
Effect of uranium deficiency on normal and superconducting properties in unconventional superconductor UTe2
Authors: Haga Y , Opletal P , Tokiwa Y , Yamamoto E , Tokunaga Y , Kambe S , Sakai H
Published: February 2022

Single crystals of the unconventional superconductor UTe2 have been grown in various conditions which result in different superconducting transition temperature as well as normal state properties. Stoichiometry of the samples has been characterized by the single-crystal x-ray crystallography and electron microprobe analyses. Superconducting samples are nearly stoichiometric within an experimental error of about 1%, while non-superconducting sample significantly deviates from the ideal composition. The superconducting UTe2 showed that the large density of states was partially gapped in the normal state, while the non-superconducting sample is characterized by the relatively large electronic specific heat as reported previously.
Pair structure, diffusion and pressure in liquid CuZr alloys from ab initio simulations: assessing the sensitivity to the energy cutoff
Authors: Amokrane S , Ayadim A , Levrel L , Jakse N
Published: February 2022

An accurate determination of the liquid structure, dynamics and thermodynamics on the same footing from ab initio molecular dynamics requires particular attention in setting up the electronic structure calculation. Using two well established simulation codes implementing the density functional theory with modern projector augmented wave sets, extensive ab initio molecular dynamics runs have been performed on the CuZr liquid alloy, a prototype of glass-forming alloys. Simulation cells involving about 3000 electrons and energy cutoffs from 285 up to 640 eV, well above the values usually taken in simulations of liquid alloys have been used. The influence of the energy cutoff on structural and thermodynamic properties is examined, with a view to estimating the limiting values required for providing reliable reference data for the classical simulations with parametrized force fields. The impact on classical simulations is illustrated with optimized embedded atom model potentials using the force matching method. The various data collected confirm that the ionic pair structure and the diffusion are indeed well converged for energy cutoffs larger than about 285 eV. The greater sensitivity observed for the pressure underlines the necessity to pay more attention to the question of incomplete basis set and the structure independent electronic contributions.
Rapid estimation of π by weighing triangles, circles, and ellipses
Authors: Pili Unofre B
Published: February 2022

This article presents a simple, fast, and equally accurate technique for measuring the area of a circle and of an ellipse without using geometric formulas. This therefore, together with the known radius of the circle and the semi-major and semi-minor axes of the ellipse, allows for the calculation of π. The experiment is easy, thrilling, and fun to replicate as a math or physics classroom activity, for high school freshmen or sophomore, in celebration of the famous constant and irrational number. In addition, the graphical data reveal an empirical derivation of the area of the circle and of the ellipse which is academically-enriching, for the students most specially.
Pendulum: the partial and global approach
Authors: Lopes Coelho Ricardo
Published: February 2022

The pendulum was an important scientific instrument in the 17th century. It became a typical textbook problem in the 18th century. After the introduction of vectors in physics in the 1890s, the pendulum problem started to be progressively solved in the manner we know nowadays from introductory mechanics courses. Starting from F = ma and using the tangential component of weight, we arrive at the equation of motion. The other part of F = ma, which concerns the weight radial component, tension and centripetal force, has in no way deserved the same attention from textbook writers, if any. Physics education research has, however, pointed out relevant aspects of the phenomenon related with the latter part of the equation. The present paper presents an experiment, which reflects those relevant aspects, and provides a mathematical insight into the phenomenon suitable for the high school student.
Measurements of fluctuating electron temperature and space potential in a magnetized plasma with a single magnetically insulated baffled probe (MIBP)
Authors: Li Shubo , Yuan Chengxun , Kurlyandskaya Iya P , Demidov V I , Koepke M E , Yao Jingfeng , Zhou Zhongxiang
Published: February 2022

A single magnetically insulated baffled probe (MIBP) was used to study the potential and electron temperature oscillations in a magnetized plasma. It was shown, that, although the MIBP cluster allows a more detailed study of such oscillations, the single MIBP may provide useful information about the oscillation amplitudes and, in some cases, cross-coherency and cross-phase. These quantities can characterize oscillations and distinguish co-oscillating plasma parameters in cases where the placing of a MIBP cluster in a plasma is difficult or impossible. For the reported plasma case, in which there are two types of oscillations, it is shown how to determine the maximum and minimum possible values of the electron temperature fluctuations. Detailed analysis showed that, in the studied plasma, there are two types of oscillations, both incoherent with each other.
Intra- and interband excitations induced residue decay of the Bose polaron in a one-dimensional double-well
Authors: Chen Jie , Mistakidis Simeon I , Schmelcher Peter
Published: February 2022

We investigate the polaronic properties of a single impurity immersed in a weakly interacting bosonic environment confined within a one-dimensional double-well potential using an exact diagonalization approach. We find that an increase of the impurity–bath coupling results in a vanishing residue, signifying the occurrence of the polaron orthogonality catastrophe. Asymptotic configurations of the systems’ ground state wave function in the strongly interacting regime are obtained by means of a Schmidt decomposition, which in turn accounts for the observed orthogonality catastrophe of the polaron. We exemplify that depending on the repulsion of the Bose gas, three distinct residue behaviors appear with respect to the impurity–bath coupling. These residue regimes are characterized by two critical values of the bosonic repulsion and originate from the interplay between the intra- and the interband excitations of the impurity. Moreover, they can be clearly distinguished in the corresponding species reduced density matrices with the latter revealing a phase separation on either the one- or the two-body level. The impact of the interspecies mass-imbalance on the impurity’s excitation processes is appreciated yielding an interaction shift of the residue regions. Our results explicate the interplay of intra- and interband excitation processes for the polaron generation in multiwell traps and for designing specific polaron entangled states motivating their exposure in current experiments.
The Influence of Alkaline Treatment on Tensile Properties of Short Bamboo Fiber Reinforced Epoxy Resin Biocomposites
Authors: Nhuapeng W , Chintonguyad T. , Thamjaree W
Published: February 2022

In this work, the influence of alkaline treatment on tensile properties of short bamboo fiber reinforced epoxy resin biocomposites was investigated. Sodium hydroxide (NaOH) was used as a treatment agent. To improve the ability of adhesion, bamboo fibers were treated in NaOH solution in different concentrations and soaking times. The treated fibers were then fabricated to composites via casting technique. Mechanical properties and microstructure of biocomposites were determined using tensile testing and scanning electron microscope (SEM), respectively. From the results, it could be seen that the alkaline treatment can improve the fiber-matrix adhesion which have effect to better mechanical properties of biocomposites.
Study of Effect of Varying Clearances on the Springback of Advanced High Strength Steel Sheets
Authors: Julsri Weerapong , Uthaisangsuk Vitoon
Published: February 2022

The springback of metal sheets shows a significant effect on the forming results of automotive structural parts. The components of new vehicles often have complex shapes, for which more precise forming procedures are required in order to achieve their desired geometries. Such springback occurrence is highly critical in the case of advanced high strength (AHS) steels. In this work, a V-shape stamping test was carried out for the AHS steel sheets grade 980 with an initial thickness of 1 mm. In parallel, the corresponding finite element (FE) simulations were conducted. Hereby, the Yoshida-Uemori (Y-U) kinematic hardening model was applied for describing the plastic deformation and elastic recovery of material. The parameters of the Y-U model were obtained from a tension-compression test and afterwards verified by using the 1-element model. The predicted bend angles of the formed samples fairly agreed with the experimentally measured results. Furthermore, the effect of defined die clearance at the corner of the formed sample on the magnitude of springback was numerically studied. It was found that the reduction of clearance of 10% led to obviously decreased shape deviations in the V-shape forming test.
Preparation of Activated Carbon from Various Biomasses by Single-Stage Pyrolysis
Authors: Thowphan Suwimon , Kaewtrakulchai Napat , Jaruvanawat Anuchit , Chutipaijit Sutee , Puengjinda Pramote , Chollacoop Nuwong , Fuji Masayoshi , Eiad-ua Apiluck
Published: February 2022

Nowadays, activated carbon were successfully synthesized from biomass, Activated nanoporous carbon have been widely for several applications such as solution to air pollution, solution to water pollution. In this work, study the effects of pyrolysis temperature of activated carbon synthesized from coconut shell, coconut leaves, coconut bracts, cattail flower, cattail leaves, mangosteen bracts, durian bracts, corn leaves, eucalyptus bracts, sugarcane leaves and toddy palm bracts. The pyrolysis of various biomass was studied at the temperature of 700-900 °C for 2 h under N2 flow of 100 ml/min. The results showed that biomass types and pyrolysis temperature affects the structural and physicochemical properties of activated carbon such as pore structures, surface functional groups and elemental compositions. activated carbon obtained at 800 °C for 2 h had the highest composed of amorphous phase, porosity and surface area.
Effect of Type and Content of Blowing Agent on Properties of NR/EPDM/EVA Foam
Authors: Kim B , Nun-anan P , Hancharoen K , Seiichi K , Boonkerd K
Published: February 2022

This research aimed to study the influence of type and content of blowing agents on the properties of rubber foam NR/EPDM/EVA. Supercell DP, supercell RC 720, and EW5 were used here as a blowing agent. The content of the blowing agent was varied from 3 phr to 4 and 5 phr. The results showed that supercell RC 720 and OBSH were not suitable for this trinary rubber foam due to the absence of even porous structure, while the supercell DP gave the even porous structure throughout the sample and the lowest density. It was found that increasing supercell DP loading led to the increase in pore size, thermal conductivity but the decrease in the density, tensile strength, and elastic recovery of rubber foam. Owing to the lowest thermal conductivity, it can be inferred here that supercell DP at 5 phr was suitable to produce rubber foam from NR blended with EPDM and EVA for a ceiling board application.
Development of Lab-on-a-Disc Integrated with Resazurin-based Assay for Total Bacterial Counting in Raw Milk
Authors: Chamnan Pornthip , Yingkajorn Mingkwan , Saengdee Pawasuth , Ranron Norabadee , Sripumkhai Witsaroot , Pattamang Pattaraluck , Jeamsaksiri Wutthinan , Atthi Nithi , Vongkamjan Kitiya
Published: February 2022

The quality of milk and dairy products depends largely on micro-organisms contamination which can pose serious health risks. Therefore, the total viable count (TVC) in raw milk needs to be daily checked to guarantee high quality. A resazurin is used as a dye indicator for the TVC quality in raw milk. However, this method is relatively complicated and inconvenient for on-site measurement. During the wait time, changes in physical and chemical properties of the raw milk were observed and they might affect the accuracy of the test results. Therefore, lab-on-a-disc (LOAD), a low-cost, user-friendly, and fast detection centrifugal microfluidic platform for the TVC test, was proposed in this study. The LOAD device (ϕ: 9.0 cm) was fabricated by laser machining of polymethyl methacrylate (PMMA, acrylic) and assembled with pressure sensitive adhesive (PSA) films. The 10 %(v/v) of resazurin-based assay that incubated at 25 °C was used to detect three different bacterial concentration levels of 4.0 log CFU/mL (low), 6.0 log CFU/mL (medium) and 8.0 log CFU/mL (high) in raw milk. The reduction process changed the color from purple (resazurin) to pink (resorufin) and to white (dihydroresorufin) subsequently. The resazurin and resorufin showed the maximum absorbance at the wavelength of 600 and 570 nm, respectively. After the LOAD was rotated at 5000 rpm for 5 minutes at 25 °C, the color of resazurin in the raw milk with medium and high levels of bacterial concentration started to change from purple to pink at 60 and 15 min, respectively. However, the color of resazurin in raw milk with low level of bacterial concentration remained dark mauve after 120 min. Overall, the LOAD integrated with resazurin-based assay is an alternative method to determine TVC in raw milk and various food stuffs.
Preparation of ZnO Nanoparticles Water-based Dispersion
Authors: Thonglerth P , Sujaridworakun P , Boondamnoen O
Published: February 2022

In this work, an attempt was made to stabilize ZnO NPs as water-based dispersion. The dispersing agents used are 3-glycidoxypropyltrimethoxysilane (GPTMS), polyvinyl alcohol (PVA) and oleic acid (OA). These dispersing agents were combined with sodium dodecyl sulfate (SDS) to facilitate better dispersion stability. Different wt% content of modified ZnO NPs such as 0.2, 0.4, 1 and 3% w/v was used at a fixed ratio of ZnO NPs:SDS:dispersing agent. The highest dispersion stability was achieved at 1% w/v content of modified ZnO NP, whereas some precipitate was observed at 3% w/v. The result reveals that sonication at 30 minutes produced the highest dispersion stability whereas extended sonication led to re-agglomeration of ZnO NPs. The optimum ratio of ZnO NPs:SDS:dispersing agent which produced about 98% dispersion stability was at 1:0.25:0.2. The zeta potential (ZP) values of ZnO NPs/GPTMS, ZnO NPs/PVA, and ZnO NPs/OA dispersions are -51, -29 and -15 mV, respectively. The ZP values was influenced by the electrical charge surrounding the particles which was also caused by the functional group of the dispersing agents. However, the stabilization mechanisms of modified ZnO NPs in water was complicated. It did not only depend on the electrostatic value but also on electrosteric stabilization caused by the steric effects hindering the dispersing agents. Interactions between the dispersing agents and ZnO NPs was confirmed through FTIR analysis.
Waste tire rubber as heavy metal ion adsorbent
Authors: Boongoi P , Opaprakasit M , Boondamnoen O
Published: February 2022

The objective of this work was to develop waste tire rubber (WTR) as a heavy metal ion (Cu(II)) adsorbent. Effects of heat and acid treatment on efficiency of Cu(II) removal were examined from h-WTR, a-WTR, h/a-WTR and a/h-WTR with 40 mesh size. Results from UV-Vis spectrometer revealed that, at 0.5g/50ml adsorbent dosage, h-WTR had higher %removal of Cu(II) than other treated-WTRs. This may result from the highest surface area (51.61 m2/g) and pore volume (0.24 cm3/g) of h-WTR. The pores were possibly formed by the departure of small compounds generated from the rubber degradation. On the other hand, acid treated adsorbent present low efficiency, positive charges of the residual acid occupied on adsorbent surfaces played an important role on the Cu(II) adsorption capacity of a-WTR, h/a-WTR. SEM image presented the number of pores on surface of h-WTR. Results from h-WTR with different size revealed that the smaller size of WTR provided the higher %removal of Cu(II). This was possibly due to the higher efficiency of surface activation. Increasing an amount of adsorbent dosage from 0.5 to 5g/50ml slightly enhanced the %removal. In this study, WTR with > 90% Cu(II) removal was achieved when heat treatment was applied on 40 mesh WTR and 0.5g/50ml adsorbent dosage.
Development of Flame Retardant Stearic Acid Doped Graphite Powder and Magnesium Hydroxide Nanoparticles, Material for Thermal Energy Storage Applications
Authors: Han Kyaw Thet , Lhosupasirirat Siraprapa , Srikhirin Pongsid , Houngkamhang Nongluck , Srikhirin Toemsak
Published: February 2022

Nano-enhanced organic phase change material (PCM) composite consists of stearic acid (SA, act as the thermal storage media), graphite powder(GP, function as thermal conductor), and magnesium hydroxide nanoparticles(nMH), micro-sized (MMH), function as the flame retarder), were formulated and investigated for their thermophysical properties and flammability. The flame-retardant properties of nano-enhanced composite PCM were evaluated by using the burning test. Phase change temperature, phase change latent heat, and thermal conductivity were obtained by the T-history method. To reduce the flammability, 5wt% of MH with 0.8μm and 200nm were added to PCMs. 1wt% of GP improved thermal conductivity of stearic acid from 0.245 to 0.4887 W/mk, and doping of flame-retardant nanoparticles to PCM showed the reduction of flammability and slightly effecting on latent heat of PCM. nMH were found to work better for stearic acid flammability than MMH, where combustion time of 0.1g pure stearic acid(SA) was decreased from 41s to 17s and 23s. For nano-sized(SA/nMH) and micron-sized(SA/MMH)composites, the latent heat of pure PCM dropped from 171.26 to 124.85KJ/kg, but micron-sized addition negatively affects latent heat values by reducing from 171.26 to 88.87 KJ/kg. The results confirmed that nMH/GP/SA composite could reduce flammability without showing a negative impact on storage capacity.
Limited role of soil texture in mediating natural vegetation response to rainfall anomalies
Authors: Gupta Surya , Bonetti Sara , Lehmann Peter , Or Dani
Published: February 2022

Evidence suggests that the response of rainfed crops to dry or wet years is modulated by soil texture. This is a central tenet for certain agronomic operations in water-limited regions that rely on spatial distribution of soil texture for guiding precision agriculture. In contrast, natural vegetation in climatic equilibrium evolves to form a dynamic assemblage of traits and species adapted to local climatic conditions, primarily precipitation in water-limited regions. For undisturbed landscapes, we hypothesize that natural vegetation responds to rainfall anomalies irrespectively of local soil texture whereas rainfed crops are expected to respond to texture-mediated plant available water. Earth system models (ESMs) often quantify vegetation response to drought and water stress based on traditional agronomic concepts despite fundamental differences in composition and traits of natural vegetation and crops. We seek to test the hypothesis above at local and regional scales to differentiate natural vegetation and rainfed crops response to rainfall anomalies across soil types and better link them to water and carbon cycles. We employed field observations and remote sensing data to systematically examine the response of natural and rainfed cropped vegetation across biomes and scales. At local scales (field to ∼0.1 km), we used crop yields from literature data and natural vegetation productivity as gross primary productivity (GPP) from adjacent FLUXNET sites. At regional scales (∼102 km), we rely exclusively on remote-sensing-based GPP. Results confirm a lack of response of natural vegetation productivity to soil texture across biomes and rainfall anomalies at all scales. In contrast, crop yields at field scale exhibit correlation with soil texture in dry years (in agreement with conventional agronomic practices). These results support the hypothesis that natural vegetation is decoupled from soil texture, whereas rainfed crops retain dependency on soil texture in dry years. However, the observed correlation of crops with soil texture becomes obscured at larger scales by spatial variation of topography, rainfall, and uncertainty in soil texture and GPP values. The study provides new insights into what natural vegetation’s climatic equilibrium might mean and reveals the role of scale in expressing such sensitivities in ESMs.
Growth rings show limited evidence for ungulates’ potential to suppress shrubs across the Arctic
Authors: Vuorinen Katariina , Austrheim Gunnar , Tremblay Jean-Pierre , Myers-Smith Isla H. , Hortman Hans Ivar , Frank Peter , Barrio Isabel C. , Dalerum Fredrik , Björkman Mats P. , Björk Robert G. , Ehrich Dorothee , Sokolov Aleksandr , Sokolova Natalia , Ropars Pascale , Boudreau Stephane , Normand Signe , Prendin Angela Luisa , Schmidt Niels Martin , Pacheco Arturo , Post Eric , John Christian , Kerby Jeff T , Sullivan Patrick F , Le Moullec Mathilde , Hansen Brage Bremset , Van der Wal Rene , Pedersen Åshild Ønvik , Sandal Lisa , Gough Laura , Young Amanda , Li Bingxi , Magnússon Rúna Íris , Sass-Klaassen Ute , Buchwal Agata , Welker Jeffery M , Grogan Paul , Andruko Rhett , Morrissette-Boileau Clara , Volkovitskiy Alexander , Terekhina Alexandra , Speed James David Mervyn
Published: February 2022

Global warming has pronounced effects on tundra vegetation, and rising mean temperatures increase plant growth potential across the Arctic biome. Herbivores may counteract the warming impacts by reducing plant growth, but the strength of this effect may depend on prevailing regional climatic conditions. To study how ungulates interact with temperature to influence growth of tundra shrubs across the Arctic tundra biome, we assembled dendroecological data from 20 sites, comprising 1,153 individual shrubs and 22,363 annual growth rings. Evidence for ungulates suppressing shrub radial growth was only observed at intermediate summer temperatures (6.5-9°C), and even at these temperatures the effect was not strong. Multiple factors, including forage preferences and landscape use by the ungulates, and favourable climatic conditions enabling effective compensatory growth of shrubs, may weaken the effects of ungulates on shrubs, possibly explaining the weakness of observed ungulate effects. Earlier local studies have shown that ungulates may counteract the impacts of warming on tundra shrub growth, but we demonstrate that ungulates’ potential to suppress shrub radial growth is not always evident, and may be limited to certain climatic conditions.
Preliminary method for profiling volatile organic compounds in breath that correlate with pulmonary function and other clinical traits of subjects diagnosed with cystic fibrosis: a pilot study
Authors: Woollam M , Siegel A P , Grocki P , Saunders J L , Sanders D B , Agarwal M , Davis M D
Published: February 2022

Cystic fibrosis (CF) is characterized by chronic respiratory infections which progressively decrease lung function over time. Affected individuals experience episodes of intensified respiratory symptoms called pulmonary exacerbations (PEx), which in turn accelerate pulmonary function decline and decrease survival rate. An overarching challenge is that there is no standard classification for PEx, which results in treatments that are heterogeneous. Improving PEx classification and management is a significant research priority for people with CF. Previous studies have shown volatile organic compounds (VOCs) in exhaled breath can be used as biomarkers because they are products of metabolic pathways dysregulated by different diseases. To provide insights on PEx classification and other CF clinical factors, exhaled breath samples were collected from 18 subjects with CF, with some experiencing PEx and others serving as a baseline. Exhaled breath was collected in Tedlar bags during tidal breathing and cryotransferred to headspace vials for VOC analysis by solid phase microextraction coupled to gas chromatography–mass spectrometry. Statistical significance testing between quantitative and categorical clinical variables displayed percent-predicted forced expiratory volume in one second (FEV1pp) was decreased in subjects experiencing PEx. VOCs correlating with other clinical variables (body mass index, age, use of highly effective modulator treatment (HEMT), and the need for inhaled tobramycin) were also explored. Two volatile aldehydes (octanal and nonanal) were upregulated in patients not taking the HEMT. VOCs correlating to potential confounding variables were removed and then analyzed by regression for significant correlations with FEV1pp measurements. Interestingly, the VOC with the highest correlation with FEV1pp (3,7-dimethyldecane) also gave the lowest p-value when comparing subjects at baseline and during PEx. Other VOCs that were differentially expressed due to PEx that were identified in this study include durene, 2,4,4-trimethyl-1,3-pentanediol 1-isobutyrate and 5-methyltridecane. Receiver operator characteristic curves were developed and showed 3,7-dimethyldecane had higher ability to classify PEx (area under the curve (AUC) = 0.91) relative to FEV1pp values at collection (AUC = 0.83). However, normalized ΔFEV1pp values had the highest capability to distinguish PEx (AUC = 0.93). These results show that VOCs in exhaled breath may be a rich source of biomarkers for various clinical traits of CF, including PEx, that should be explored in larger sample cohorts and validation studies.
A Simple Numerical Modelling of Refraction and Shoaling Wave Using VBA Excel
Authors: Danial M. M. , Meirany J. , Maulana I. , Buan B.
Published: February 2022

Wave propagation from the deep water to the shoreline experiences a transformation process. Their transformation, frequently, affects coastal processes such as erosion and sedimentation. In addition, their wave force can also damage the coastal infrastructure. There are three processes of wave transformation that should be modelled, namely, shoaling, refraction, and wave breaking. It is difficult to calculate the wave transformation manually due to the complexity of computation. Therefore, it should be handled using such commercial software, which is mostly very expensive. In order to cope with the problem, a simple numerical model of wave transformation, based on the finite difference method, is carried out using VBA Excel as a programming language. The advantage of using VBA Excel is the easy accessibility due to its integration with Microsoft Office. The aim of this project is to create a simple software for modelling refraction and shoaling waves that can be developed for educational purposes. The outcome of making this software is to meet the availability of wave modelling software in supporting the development of education and teaching in the ocean engineering field. The results of the numerical model are verified using the modelling results of Horikawa and Koutitas.
Concepts of Big Data Analysis of Container Terminals in the Digital Era
Authors: Mathias Tiago Novaes , Shinoda Takeshi
Published: February 2022

In the last few decades, with the advance of IoT technologies throughout the most different fields have been changing the way some process is handled. However, possessing a great volume of data does not mean the operation will be handled better, in many cases the data lays in the storage and stays untouched. An increasing quantity of freight imposes container terminals to improve their capacities. Therefore, decision-making problems for operation planning, controlling, and evaluation needs to be well defined. Understanding that necessity, managers need to rely on, almost exclusively, the Terminal Operational System (TOS) to identify and solve the bother necks during daily operation. Although the TOS also had some improvements in the past years due to technological advances, it is still not enough to evaluate each operational step for the operation. This paper uses a data mining and data analysis evaluation of the container terminal’s daily operation to find out specific operational issues and evaluate the main key performance indicators to keep track of the terminal efficiency.
Numerical Study of Environment Loads and Mooring Line Scope Effects to The Buoy Offset
Authors: Arifin  , Wibowo H.N. , Buddin H. , Suwahyu
Published: February 2022

The Indonesian Buoy for Tsunami Early Warning System (INATEWS - Buoy) consists of a tsunami buoy, an ocean bottom unit (OBU), a satellite and a ground station. The changes of the water pressure due to the seismic motion prior to the tsunami event will be acquired by OBU and sent the reading to the tsunami buoy by acoustic signal. One of the conditions that affect the success of sending data from the OBU to the buoy is the distance between the two (offset). Several parameters that are considered to have an effect on the occurrence of offsets on the buoy are the magnitude of the environmental load around the buoy and the value of the scope mooring line used. Environmental loads that consist of current, wave and wind loads are analyzed. Analysis of each environmental load is carried out separately to determine the level of load sensitivity to the offset buoy. In addition, a buoy offset study was also carried out on several scope values from the mooring line to determine the change in the buoy offset. Offset prediction on buoys is calculated by numerical simulation. From this numerical simulation, it found that changes in environmental load, especially changes in current speed, significantly affect the offset value of the buoy that occurs. Likewise with the determination of the mooring line scope, where the smaller the scope value used in the mooring line system, the smaller the offset value that occurs. Finally, the designed mooring systems while applied at the selected operational buoy location, will have Safety Factor 3.61 and 4.57 for wire and nylon rope mooring line components, respectively.
Method for Estimating Cost of New Ship Building with Linear Regression
Authors: Azhar A , Kristiyono T A
Published: February 2022

The request of a fleet of marine transportation can be fulfilled by constructing new vessels and purchasing secondhand vessels. The current constraints in building new vessels are cost relatively expensive and take a long time, while the advantages for the procurement of vessels of secondhand time relatif faster and the price is cheaper. New shipbuilding includes complex work with the multy year’s payment system, so it is important to develop the cost budget needed to build a new ship. The price should be adjusted concerning material needs and services with the standard market price during the completion time of the work and expected the calculation of the construction of a ship can be updated periodically. The research aims to identify, analyse and construct the cost estimation of the construction of the ferry types: 300 GT, 500 GT, 600 GT, 750 GT and its components. The stages that will be carried out in this study are to identify primary and secondary data relating to the construction costs of ferries and their components with field surveys, market surveys, and relevant library studies. Data is processed by linear regression methods to construct an estimate of the cost of building ferries and their components. Results obtained in the form of graphs and equivalencies of the cost of building ferries and material cost components, labour costs, and shipyard and third party costs.
Structural Strength Assessment of 20-ft LNG ISO Tank: an Investigation of Finite Element Analysis and ASME Design Guidance
Authors: Muttaqie Teguh , Sasmito Cahyo , Iskendar  , Kadir Abdul
Published: February 2022

Following the high demand for LNG as low emission and eco-friendly energy, ISO tank containers are present as an innovative product to support the mass transportation of LNG in a cheap, effective and efficient manner. The 20-ft ISO tank is a container with a pressure vessel structure that can be intermodal with sea or land transportation like other standard dry box containers. The purpose of this paper is to present a complete procedure for evaluating the scantling size of the 20 ft ISO tank LNG type. The criteria are determined based on the standard ASME section VIII division I code for boilers and pressure vessels. The calculation includes the fulfilment of the thickness and conformity with the internal and external pressure design requirements. In addition, the finite element investigation was conducted under the various design loads and operating conditions. This analysis provides the safety level of the ASME design guidance in comparison with ISO standard FEA judgments.
Effect of CNG Engine Conversion on Performance Characteristic: A Review
Authors: Leonardo Adam , Semin
Published: February 2022

The world has been experiencing a crisis of energy caused by the deterioration of scarce fossil fuel resources. The usage of fossil fuels, mainly liquid fuels is considered unsustainable due to resource depletion and the accumulation of pollutants. Natural gas has become a promising alternative fuel since it is highly abundant in the world, produces less emission, and gives similar engine performance compared to the existing liquid fuel, diesel, or gasoline. This paper presents various research regarding the engine performance characteristic of CNG. The studies reported that as compared to liquid-based fuel such as diesel oil or gasoline, CNG gives lower brake thermal efficiency (BTE) as compared to diesel fuel. However, the brake-specific fuel consumption (BSFC) of engine fueled with CNG is lower than diesel or gasoline fuel. In terms of exhaust gas temperature, CNG was always produced higher temperatures in comparison to gasoline. The maximum cylinder gas pressure of CNG was reported lower than diesel fuel operation. In general, the power produced by CNG combustion is a little bit lower than diesel fuel, this drawback of CNG fuel can be overcome by adding hydrogen fuel to CNG to increase produced power.