bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved moisture resistance and interfacial recombination of perovskite solar cells by doping oleylamine in spiro-OMeTAD based hole-transport layer
Authors: Liu Shan , Wu Shuyue , Xia Pufeihong , Xie Haipeng , Yuan Xiaoming , Li Youzhen , Kong Deming , Huang Han , Gao Yongli , Zhou Conghua
Published: June 2022

Hydrophobic and long-chain molecule oleylamine is used to modify the spiro-OMeTAD matrix, which is then adopted for the hole-transport layer in perovskite solar cells. It is observed that after moderate doping, the power conversion efficiency of the devices increases from 17.82 (±1.47)% to 20.68 (±0.77)%, with the optimized efficiency of 21.57% (AM 1.5G, 100 mW/cm2). The improved efficiency is ascribed to the favored charge extraction and retarded charge recombination, as reflected by transient photovoltage/photocurrent curves and impedance spectroscopy measurement. In addition, the grazing incidence photoluminescence spectrum reveals that oleylamine doping causes a blue shift of the luminescence peak of the surface layer of the halide perovskite film, while the Mott−Schottky study observes 100 mV increment in the built-in potential, both of which indicate possible defect passivation behavior on the perovskite. Moreover, an accelerated damp test observes that moisture resistance of the device is also upgraded, which is due to the improved hydrophobicity of the spiro-OMeTAD matrix.
Nonlinear oscillations of a collapsible tube subjected to unsteady external pressure
Authors: Kumar Kamlesh , Prabhakaran Deepu
Published: June 2022

The non-linear dynamics of an extremely thin-walled collapsible tube with internal flow subjected to a time-varying external pressure are studied experimentally and theoretically. For the constant chamber pressure case, we observe the existence of a fixed-point attractor, period-1 attractor, and quasiperiodic attractor. The period-1 limit cycle oscillations are essentially relaxation oscillations with up-down asymmetry in the time domain, and as the Reynolds number increases, the asymmetry becomes greater. With the forcing (varying chamber pressure), the system has no fixed points; its response can be period-n, quasiperiodic, or chaotic, depending upon the Reynolds number, driving amplitude, and frequency. For the forced system, at a low Reynolds number, the external forcing dominates the self-excited oscillations and symmetric oscillations are observed; at a higher Reynolds number, the reverse is true. In experiments and theory, aperiodic oscillations for the forced system are always observed in regimes beyond the Hopf bifurcation point of the unforced system. Distended and collapsed cases, under forcing, exhibit only 1:1 synchronous oscillation. These suggest that a natural oscillation timescale of the system must be present for the external forcing to induce aperiodicity. In the experiments, the forced system exhibits signs of quasiperiodic route to chaos at lower driving amplitude, while period-doubling route to chaos at higher driving amplitude. When the system is forced near its natural frequency, an aperiodic response is totally suppressed.
Impact of passivation on the Dirac cones of 2D topological insulators
Authors: Deylgat Emeric , Tiwari Sabyasachi , Vandenberghe William G. , Sorée Bart
Published: June 2022

Topological insulators have unique properties that make them promising materials for future implementation in next-generation electronic devices. However, topological insulators like stanene nanoribbons need to be passivated before they can be used in devices. We calculate the electronic band structure of stanene nanoribbons (SNRs) that are passivated by hydrogen (H), fluorine (F), chlorine (Cl), bromine (Br), iodine (I), or sodium (Na). We show that the difference between the electronegativity of the passivation material and the tin atoms defines the position of the Dirac cone of the topological insulator edge states. We develop a four-parameter tight-binding model based on the Kane–Mele model [Kane and Mele, Phys. Rev. Lett. 95, 226801 (2005); Kane and Mele, Phys. Rev. Lett. 95, 146802 (2005)]. The hopping parameters of the TB model are obtained by fitting the tight-binding model to the density functional theory (DFT) calculations. Finally, we demonstrate that the DFT band structures and the tight-binding model band structures are in good agreement with each other at low energies around the Dirac point, thereby capturing the complete physics of the passivated edge bands.
Double injection function InGaZnO transistor—computational analysis of the patterned doping method
Authors: Sheleg Gil , Tessler Nir
Published: June 2022

Metal oxide-based electronics is advancing rapidly where the reduced dimensions require transistor structures different to conventional CPUs. The double injection function transistor (DIFT) is a type of a source-controlled transistor. As doping is a facile method in the semiconductor industry, we suggest that the DIFT can be realized through a doping pattern under the source electrode. We show that double doping functions similarly to the double work function DIFT, recently demonstrated. We use device simulations to analyze the operation principle of the DIFT structure and provide design guidelines. We find that the structural separation of the injection and depletion functions allows adapting the transistor structure to fabrication process limitations. A 200 nm channel length InGaZnO based device can be designed to exhibit proper saturation at sub-1 V drain bias.
Multipactor suppression via asymmetric grooves in S-band waveguide
Authors: Wright D. , Shaw Z. C. , Mankowski J. J. , Dickens J. C. , Stephens J. , Neuber A. A.
Published: June 2022

To investigate multipactor, we designed a testbed for S-band frequencies with geometries akin to the standard WR-284 waveguide geometry. Narrowing the waveguide height from WR-284 dimensions to 5.5 mm for a suitable frequency-gap product left the waveguide cutoff frequency unaffected and the RF signal propagating in the dominant TE10 mode. A coaxial magnetron provides the test input power at 2.85 GHz with a peak power output of 4 MW and a 3.5 μs pulse width, and an RF solid-state source using gallium nitride high-electron-mobility transistors delivers a pulse width of 100 μs with a test input power of 2 kW for comparison of threshold power. Local (electron multiplier tube) and global (phase/power) diagnostic methods are implemented to detect multipactor within the test setup. At power levels tested (MW) and a 5.5 mm gap, low multipactor orders (N = 1) are observed. Prior numerical studies demonstrated that structures with grooves in the waveguide broadside wall reduced multipactor susceptibility. Such grooves run along the direction of propagation to avoid continuous impedance mismatching. The efficacy of this mitigation technique was experimentally evaluated. Differences over a smooth broadside wall are noticeable, however limited.
Lossless plasmons in highly mismatched alloys
Authors: Allami Hassan , Krich Jacob J.
Published: June 2022

We explore the potential of highly mismatched alloys (HMAs) for realizing lossless plasmonics. Systems with a plasmon frequency at which there are no interband or intraband processes possible are called lossless, as there is no two-particle loss channel for the plasmon. We find that the band splitting in HMAs with a conduction band anticrossing guarantees a lossless frequency window. When such a material is doped, producing plasmonic behavior, we study the conditions required for the plasmon frequency to fall in the lossless window, realizing lossless plasmons. Considering a generic class of HMAs with a conduction band anticrossing, we find universal contours in their parameter space within which lossless plasmons are possible for some doping range. Our analysis shows that HMAs with heavy effective masses and small high-frequency permittivity are most promising for realizing a lossless plasmonic material.
Brain tract structure predicts relapse to stimulant drug use
Authors: Tisdall Loreen , MacNiven Kelly H. , Padula Claudia B. , Leong Josiah K. , Knutson Brian
Published: June 2022

Diffusion tractography allows identification and measurement of structural tracts in the human brain previously associated with motivated behavior in animal models. Recent findings indicate that the structural properties of a tract connecting the midbrain to nucleus accumbens (NAcc) are associated with a diagnosis of stimulant use disorder (SUD), but not relapse. In this preregistered study, we used diffusion tractography in a sample of patients treated for SUD (
n
= 60) to determine whether qualities of tracts projecting from medial prefrontal, anterior insular, and amygdalar cortices to NAcc might instead foreshadow relapse. As predicted, reduced diffusion metrics of a tract projecting from the right anterior insula to the NAcc were associated with subsequent relapse to stimulant use, but not with previous diagnosis. These findings highlight a structural target for predicting relapse to stimulant use and further suggest that distinct connections to the NAcc may confer risk for relapse versus diagnosis.
Temporally and anatomically specific contributions of the human amygdala to threat and safety learning
Authors: Wen Zhenfu , Raio Candace M. , Pace-Schott Edward F. , Lazar Sara W. , LeDoux Joseph E. , Phelps Elizabeth A. , Milad Mohammed R.
Published: June 2022

Neural plasticity in subareas of the rodent amygdala is widely known to be essential for Pavlovian threat conditioning and safety learning. However, less consistent results have been observed in human neuroimaging studies. Here, we identify and test three important factors that may contribute to these discrepancies: the temporal profile of amygdala response in threat conditioning, the anatomical specificity of amygdala responses during threat conditioning and safety learning, and insufficient power to identify these responses. We combined data across multiple studies using a well-validated human threat conditioning paradigm to examine amygdala involvement during threat conditioning and safety learning. In 601 humans, we show that two amygdala subregions tracked the conditioned stimulus with aversive shock during early conditioning while only one demonstrated delayed responding to a stimulus not paired with shock. Our findings identify cross-species similarities in temporal- and anatomical-specific amygdala contributions to threat and safety learning, affirm human amygdala involvement in associative learning and highlight important factors for future associative learning research in humans.
Atmospheric pressure Townsend discharge in pure nitrogen—a test case for N2(

A3Σu+,v

) kinetics under low E/N conditions
Authors: Bílek Petr , Kuthanová Lucia , Hoder Tomáš , Šimek Milan
Published: June 2022

This work investigates the kinetics of the N2(

A

3

Σ

u

+

,
v

) state in the atmospheric-pressure Townsend discharge (APTD) operated in a barrier discharge setup in pure nitrogen. To understand the complex nature of the N2(

A

3

Σ

u

+

,
v

) state we have developed a detailed state-to-state vibrational kinetic model of N2 applicable mainly at low reduced electric fields (

<

200 Td). The kinetic model benefits from the determination of the electric field and the electron density profile using the equivalent electric circuit analysis. The knowledge of both parameters significantly reduces the number of free parameters of the model and thus improves the accuracy of kinetic predictions. The results of the kinetic model are compared with the measured emission spectra of the second positive system and the Herman infrared system of N2. The use of the sensitivity analysis method leads to a better understanding of the role of specific elementary processes in the APTD mechanism and also to the determination of the density of the two lowest vibrational levels of N2(

A

3

Σ

u

+

), which varies between 1012 and 1014 cm−3 depending on the applied voltage. The determination is important, because the two lowest vibrational levels of N2(

A

3

Σ

u

+

) are considered to play an important role in the secondary emission of electrons from dielectric surfaces. This work shows that the complex state-to-state kinetic modeling in combination with the phase-resolved emission spectroscopy is the key to a better understanding of the processes responsible for establishing and sustaining the APTD mechanism in nitrogen.
Analysis of influence of concrete stiffness reduction on mid-span deflection of PC box girder bridge
Authors: Sun Fan , Fang Miaomiao , Liu Jiaxin
Published: June 2022

At present, the concept of bridge preventive maintenance has been widely used. In order to find the right time for PC bridge maintenance and make better maintenance decision, it is necessary to predict the service performance of PC bridge. In this paper, the service performance of PC bridge is divided into several indexes, and the fuzzy neural network method is used to calculate these indexes data. Taking shangtan bridge as an example, the maximum relative error between the measured value and the predicted value is found to be within 5%, which meets the accuracy requirements. The feasibility of this method is verified and provides guidance for the future decision-making of bridge maintenanc.
Leakage prediction of water supply network based on SAA-SVM model
Authors: Zhang Zhenxing , Lv Mou
Published: June 2022

In order to explore the relationship between leakage, leakage failure form and pipeline pressure, the SAA-SVM model is established based on Support Vector Mechanism. The simulated annealing algorithm is used to optimize the parameters c and g of SVM, which greatly improves the accuracy of SVM and the ability to jump out of the local optimal solution. In laboratory, the leakage data under various working conditions are measured through the water supply network model. It is input into SAA-SVM model as sample data set for optimizing the model by machine learning. The results show that the optimized SAA-SVM can predict the leakage shape and loss quickly and accurately.
Statistical Characteristics of Recycled Aggregate Permeable Concrete
Authors: Yang Huan
Published: June 2022

In view of the randomness of mechanical properties and durability of recycled aggregate permeable concrete, a method combining the goodness of fit test with Bayes theory was proposed to analyze its statistical characteristics probability model. Firstly, the optimal probability distribution type of recycled aggregate permeable concrete strength was identified by goodness of fit method. Then, Bayes method was used to estimate the parameters of probability model. Finally, the reliability theory was used to evaluate the durability of recycled aggregate permeable concrete. This method has good theoretical significance and practical value for reasonable evaluation of mechanical properties and durability of recycled aggregate permeable concrete.
Sequence of Factors Affecting Stability of Tunnel Exit Section in Low Temperature Rain and Snow Weather
Authors: Heng Wu , Ting Peng , Kesheng Yang , Taoyan Zhou
Published: June 2022

When the vehicle is only affected by road conditions and its own speed, in the low temperature rain and snow weather. In order to clarify the order of the importance of each influencing factor at the exit section of the tunnel on the driving stability, this article uses the analytic hierarchy process to sort them. The results show that the order of importance is: Friction coefficient μs
> driving speed ν (m/s)> circular curve radius R (m), longitudinal slope i (%). According to the sorting results, targeted safeguard measures can be provided for the tunnel design, operation and use process.
Factors Impacting the Intensity of Vortex Shedding on High-Rise Buildings
Authors: Ke Yanyu , Shen Guohui , Yu Hangcong , Xie Jiming
Published: June 2022

The wind-induced response of tall buildings is usually dominated by dynamic across-wind vortex shedding. The intensity of vortex shedding depends on not only the model configurations but also the turbulence around the structure. The building models with different configurations including chamfer, crown opening, and porous crown were tested in different turbulent conditions. The 10% chamfered ratio has a more considerable benefit in suppressing the intensity of vortex shedding compared with the 7.5% chamfered ratio. The slotted crown has a more beneficial effect in suppressing the wind-induced responses due to resonance caused by vortex shedding compared with the one without opening. The model with 50% crown porosity has a more considerable benefit in suppressing the intensity of vortex shedding compared with the solid crown. The model with turbulent condition both the suburban exposure and interference of surroundings has a more considerable benefit in disrupting the vortex shedding compared with the model in open exposure without interference.
Research on Case-based BIM Aided Design List Management
Authors: Ye Tianzhen , Xing Enzhong , Liu Jiali , Na Yanling , Jiang Wenhua
Published: June 2022

In recent years, China has entered a period of rapid development of urban rail transit construction. Building information modeling technology (BIM) has been widely used in the design stage of urban rail transit engineering, but there is a waste of BIM design resources, and there is a lack of scientific and systematic BIM technology application mode and management methods. Based on this, this article summarizes six BIM application modes that are prone to problems in design and contributes greatly to construction, and summarizes the work content, management methods and application effects of each application mode. Then, we investigated the charging situation of the aforementioned BIM application mode for subway projects of five domestic companies, which provided a reference for the choice of BIM application mode. Finally, combined with the construction of Tianjin Line 5, it is demonstrated that the use of BIM aided design list management can maximize the application of BIM technology to value points in the design stage under the condition of limited construction capital investment, which can effectively improve the effect of BIM application, Capital utilization rate and project management level.
Study on Internal Traffic Organization Modes for Underground Parking Systems in the Urban Central Business District
Authors: Zhang Ping
Published: June 2022

As a result of urban land shortage and saturation, the development and construction of underground parking have become an inevitable trend of current social development. This paper describes both the concept and construction necessity of underground parking system by analyzing the current status of the parking situation in urban central business district (CBD). According to several case studies for the building of underground parking system around the world, four different layouts such as ridge-like, ring, radial, and network for underground parking systems are proposed. The internal channel of an underground parking system consists of primary and secondary channels and the internal channel setting of the underground parking system is directly related to the organization of the internal traffic flow. The setting of underground vehicle lanes and underground parking units in the system is considered to determine the internal traffic organization of four layout modes of an underground parking system. The findings of this research provide both theoretical and technical support for the planning and design of underground parking system.
Research on Passive Reconstruction and Energy Supply System of Existing Buildings in Cold Areas
Authors: Xu Feng , Ding YuTing , Zhang Hongxi , Zhang Yu
Published: June 2022

Faced with the problems of existing buildings in cold areas, such as poor insulation performance of envelope, high heating cost and substandard indoor temperature in winter, based on DeST-h energy consumption simulation software, taking typical single buildings in Zhangjiakou as an example, several factors affecting building energy consumption were analyzed. The building energy consumption values in heating season under 9 envelope reconstruction conditions were obtained by orthogonal experiments, and 4 different energy supply systems were designed for buildings under 9 envelope reconstruction conditions. The “with or without comparison method” is used to evaluate the building energy efficiency of 40 working conditions after the superposition of the initial state and passive transformation of existing buildings in the whole life cycle. The evaluation results show that the external wall insulation and extrusion plate thickness is 80 mm, the roof insulation and extrusion plate thickness is 100 mm, and the glass type is ordinary hollow glass ( 6 + 9 + 6 ). The air source heat pump assisted energy supply effect is the best, but the overall economy will change with the initial investment, local electricity price policy and building scale.
The fundamental studies on the reaction kinetics of thermal decomposition of bio-composite based backsheet materials in photovoltaic (PV) panel
Authors: Zulkeply M , Pang M M , Vaithilingam C A , Sivasubramanian R
Published: June 2022

This research presents the reaction kinetics of thermal decomposition of vetiver filled Polylactic Acid (PLA) bio-composite based backsheet in Photovoltaic (PV) panel via the Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The conventional PV backsheet called TEDLAR (Polyvinyl Fluoride, PVF) is made from petroleum, a non-biodegradable material which will impose serious problems to the environment at the end-of-life of the PV modules. Therefore, it is important to identify the suitability of PLA/vetiver to replace TEDLAR. The best composition of PLA/vetiver producing the lowest thermal degradation is discussed by analysing the activation energy of the bio-composites with different weight percent (wt. %) of PLA/vetiver. The result showed the wt. % of PLA/vetiver with lower content of the natural fibre has a lower thermal degradation temperature which indicates the rapid start of the degradation process. However, TEDLAR degrades at an average temperature of 400°C proving the ability to withstand extreme temperatures, thus it does not degrade easily. The results showed the higher the content of the vetiver, the lower the degradation temperature. The activation energy of the bio-composites was calculated using the Kissinger method and the estimation values of the different doses of PLA/vetiver range between 28 to 77 kJ/mol.
Design and simulation of dynamic voltage restorer (DVR) for power quality improvement
Authors: Chong K V R , Hoon Y , Ahmad H
Published: June 2022

Power quality (PQ) is one of the main issues faced in the present era. The PQ issues such as voltage sags, swells, harmonics, and unbalance as well as the impact on sensitive loads are often occurred in any power distribution system. To tackle the issues, a powerful dynamic voltage restorer (DVR) is commonly installed. However, the existing control algorithms for DVR are found to be complex, potentially increases computational burden to the controller. Therefore, in this paper, a new simplified control algorithm which utilizes the strengths of synchronous rotating frame (SRF) and phase-locked loop (PLL) concepts, is proposed to better manage operation of DVR. The DVR system is modelled and simulated by using MATLAB/Simulink platform. Performance of the newly proposed algorithm for DVR is tested in three-phase system with voltage sags, swells, harmonics and unbalances conditions. From the findings, it can be concluded that the proposed algorithm for DVR which installed in a three-phase power distribution system effectively mitigated the voltage sags, swells and unbalances conditions and, for harmonics condition, it is found to be able to minimize and contain the harmonic contents within the acceptable level.
Developing Highly Porous Glass Microspheres via a Single-Stage Flame Spheroidisation Process
Authors: Nuzulia N A , Islam T , Saputra A , Sudiro T , Timuda G E , Mart T , Sari Y W , Ahmed I
Published: June 2022

Glass microspheres are gaining attention in bone tissue engineering due to their ability to convert into hydroxyapatite-like materials, resembling the inorganic mineral of natural bone. The morphology of glass microspheres as starting material has been considered to influence the conversion rate and the resulting product where porous microspheres could promote faster conversion to hydroxyapatite than solid microspheres. This paper reports on manufacturing glass microspheres (solid and porous) using a flame spheroidisation process. The effect of various gas ratios of acetylene and oxygen on the morphological changes of glass microspheres was investigated. Irregular shaped glass particles with starting particle size ranges of 63 – 125 μm were used as feed and delivered to a hot flame to produce solid microspheres. To manufacture porous glass microspheres via a single-stage flame spheroidisation process, calcium carbonate was utilised as a porogen and mixed with the glass particles. Solid and porous glass microspheres were successfully produced, exploring various gas ratios of 3:3, 4:7, 5:7 and 6:7 with a mean particle size range between 73 – 105 μm. Moreover, the average pore size of 6 μm and 9 μm was obtained using 5:7 and 6:7 gas ratios, respectively. This single-stage flame spheroidisation process is a promising method for producing both solid and porous bioactive glass microspheres.
The Effects of Physical and Geometrical Properties on Rock Brittleness Index Based on Numerical Modeling
Authors: Lubis F H , Fatkhan  , Fauzi U
Published: June 2022

Rock brittleness is a key parameter to quantify and evaluate the brittle nature of the rock. A better estimating technique of rock brittleness is crucial for acquiring an efficient stimulation of unconventional shale gas reservoirs such as hydraulic fracturing. One way to predict rock brittleness index is by using rock elastic moduli. These physical properties highly depend on the complexity of the microstructure, fluid content, and mineral composition. The other way is by measuring the rock mineral composition itself. This complexity of the microstructure can be accurately characterized by using imaging techniques such as micro-CT scans. This study used the finite element method to estimate rock brittleness index based on elastic properties on synthetic and digital rock images. We then evaluate the effect of physical and geometrical properties (pore aspect ratio, water saturation, and mineral composition) in determining the rock brittleness characteristic. The results indicate that there is an increase in Young’s modulus along with an increasing pore aspect ratio to 1, which in turn raises the rock brittleness. Fluid saturation, in this case, water saturation, causes brittleness to be increased. The rock mineral composition, such as abundant quartz and carbonate content, yields high brittleness values, while high clay content and porosity lower the rock brittleness. Overall, the results imply that pore geometry, fluid saturation, and mineral composition significantly alter the rock strength parameters.
Near-surface resistivity imaging using resistivity Tomography in some most impacted areas due to the 2018 Earthquake in North Lombok Island
Authors: Nurhandoko Bagus Endar B. , Sukrisna Bakti , Widowati Sri , Asmarahadi Muhammad Rizka , Yasin Syamsudin , Kurniawidi Dian W. , Martha Rio , Triyoso Kaswandhi , Asmawati Diah , Fatiah Elfa , Hariman Yoga , Susilowati  , Supriyanto Eko Bambang , Guntara Wisnu Adi , Bakti Insan Rizal , Wibowo Satryo Agung , Sukmana Indriani
Published: June 2022

The Lombok earthquake in July 2018 caused considerable damage to public facilities and residential areas. Most of the houses in the north of the island of Lombok were damaged by the 6.9 magnitude earthquake. We want to know what parameters cause houses and buildings in North Lombok not to experience a severe liquefaction process. We used near-surface tomographic resistivity imaging to characterize the subsurface of North Lombok to map the subsurface of the most affected areas in North Lombok. The geological condition of northern Lombok is the most vulnerable area to liquefaction due to volcanic loose sand layers, shallow groundwater, and thick deposits. However, almost all subsurface images from resistivity tomography from North Lombok show limestone layers at shallow depths, which may play an important role as a protective layer from liquefaction phenomena in this area.
Real-Time Monitoring System for Thermocouple Inhomogeneity Equipment
Authors: Nugraha H , Imaduddin A , Achmadi A , Suryadi  , Wismogroho A S
Published: June 2022

Thermocouple inhomogeneity equipment was developed to measure the Seebeck coefficient characteristic in each wire position based on the effect of temperature exposure along the thermocouple wire. Temperature and distance sensors are used to measure the temperature output of the heating system and the movement of the thermocouple position. We developed a real-time measurement system to monitor the measurement of the thermocouple sensor based on a microcontroller. This monitoring system is needed to monitor changes in the ice bath during measurement, if the ice bath was unstable or being melting, it can affect the output voltage of the thermocouple. The program was compiled and uploaded to ESP 32 then monitoring data with an open-source internet of things called Thingspeak was used as a platform to retrieve and display the collected data. Real-time monitoring of distance from ultrasonic and temperature of heat source (heat gun) can be accessed through web applications and smartphones. The data were analyzed based on conditions for Seebeck value of inhomogeneity and validated with standard calibration using the liquid bath. This study has been considered successfully implemented that performs on IoT platforms and was adaptively ready to monitor thermocouple inhomogeneity equipment.
Design of Borehole Seismometer Based on MEMS Accelerometer
Authors: Cysela R Y , Setiawan T , Fatkhan
Published: June 2022

Conventional seismometers use coil as the main sensor. Coil is relatively cheap, but in order to cover low frequency range, it becomes frail and has inappropriate a sampling rate. To overcome the limitation of conventional seismometers we use a MEMS sensor. The sensor is made from glass and silicon substrate which has no harmonic frequency characterization. It enables covering wide bandwidth with low frequency cover and high sampling rate response with high sensitivity. The usage of MEMS in electronics such as disk drive heads and inkjet printer heads. MEMS sensor also is used in different domains which include medical, automotive, communications and defence. This paper described a borehole seismometer that was composed of a MEMS accelerometer colibrys 1500SN. An arduino micro controller. Based on data calibration and physical simulation, MEMS sensor offers the potential to reduce costs while improving data quality.
Surface stability and electronic structure of CuNi alloy (111) as a potential catalyst for graphene growth-a density-functional theory study
Authors: Yutomo E B , Noor F A , Winata T
Published: June 2022

Controlling the number of graphene layers during its growth is essential in realizing its practical application as a transparent conductive electrode. Growth with CuNi alloy catalysts can effectively control the number of graphene layers. However, research at the experimental level has not been supported by research at the theoretical level. Therefore, we will study the growth of graphene on a CuNi catalyst using the density functional theory (DFT). However, in this paper, we only focus on studying the stability of the surface of CuNi as a preliminary study. Based on geometry optimization, CuNi (111) has a wrinkled surface in the slab model due to the anisotropy shift of the atoms. Furthermore, CuNi (111) has a surface energy of 1.511 J/m2, which is between the surface energies of its components. This condition indicates that CuNi (111) has excellent stability. When forming CuNi alloy, electrons in the Cu 4s and Ni 3d orbitals have an enormous contribution in forming the metallic bonds indicated by a significant shift of the band center energy and change of the number of states at the Fermi level. Our results show that the CuNi system can become a potential catalyst for graphene growth.
Physical properties of Sidikalang robusta coffee beans medium roasted from various colors of coffee cherries
Authors: Yusibani E , Putra R I , Rahwanto A , Surbakti M S , Rajibussalim  , Rahmi
Published: June 2022

The purpose of the present study is to investigate the physical properties of medium roasted Sidikalang robusta coffee beans that originated from various colors of coffee cherries. A semi-wet method has been applied for each coffee cherry with a range of fruit ripeness (green, yellow, orange, bright red and dark red). The physical properties measurements include mass loss, mass density, porosity, and water content. After roasted for medium level, the coffee density is difference for each coffee cherries colors namely 0.42 g/cm3 (green cherries), 0.31 g/cm3 (yellow cherries), 0.40 g/cm3 (orange cherries), 0.34 g/cm3 (bright red cherries), and 0.25 g/cm3 (dark red cherries). The mass declined after medium roasted is 16.82% (green cherries), 17.00% (yellow cherries), 18.70% (orange cherries), 18.32% (bright red cherries) and 16.76% (dark red cherries). The coffee beans porosity difference before and after medium roasted is decreases by 13.56% for green cherries and 16% for yellow cherries and increased by 12.22 (orange cherries), 3.44% (bright red cherries), and 6.88% (dark red cherries). Finally, the water content of coffee beans was 8.38% (green cherries), 9% (yellow and orange cherries), 7.91% (bright red cherries), and 10.83% (dark red cherries). The present study concludes that cherries colors have influenced the coffee bean’s physical properties before and after medium roasting.
The Study of the Swelling Degree of the PVA Hydrogel with varying concentrations of PVA
Authors: Asy-Syifa Nabila , Kusjuriansah  , Waresindo William Xaveriano , Edikresnha Dhewa , Suciati Tri , Khairurrijal Khairurrijal
Published: June 2022

Hydrogel is composed of a three-dimensional network of hydrophilic polymers and can swell when placed in an aqueous media. Polyvinyl alcohol (PVA) is a common polymer used to produce hydrogels because it has biocompatibility, non-toxicity, chemical stability, low cost, and excellent mechanical strength. In this study, the PVA solutions were prepared with concentrations of 6%, 8%, 10%, and 12% in distilled water. The precursor solutions underwent a freeze-thaw cycle with a freezing temperature of -25 °C for 20 hours and a thawing temperature of 37 °C for 4 hours and carried out for 6 cycles. The swelling degree and the gel fraction of the hydrogel were then determined. From the swelling degree results, the increase of the PVA concentration in the precursor solutions reduced the swelling degree of the hydrogel. Based on the gel fraction test, it was revealed that all PVA concentrations have approximately the same value of gel fraction at 97%. Additionally, the viscosity and the density were also measured. Both showed an increasing trend with the addition of PVA concentration, where the viscosity values from the smallest to highest concentrations were 12.4944, 34.1737, 93.8491, and 216.2979 cP while the density values were 0.9865, 0.9871, 0.9878, and 0.9885 gram.cm-3.
A facile approach for preparing Zr-BDC and Zr-BDC-NH2 MOFs using solvothermal method
Authors: Rahmidar Lena , Gustaman Syarif Dani , Suyatman  , Nugraha
Published: June 2022

In the last two decades, researchers have developed new compounds made of central metals that bond in coordination with organic ligands as linkers (for example, benzene-dicarboxylic acid or BDC). These compounds are called metal-organic frameworks (MOFs) which are also known as coordination polymer compounds. MOFs have large surface area and porosity so they can be used for various purposes, such as for adsorption and removal of hazardous materials of CO2 and Hg. Here, we proposed a facile solvothermal method for preparing two kinds of MOFs with Zr as a central metal, i.e. Zr-BDC and Zr-BDC-NH2. The synthesized MOFs were characterized using XRD, FTIR, SEM, TEM, and BET. The results show that both MOFs have a crystalline structure with cubic form on the surface of MOFs. Results of the FTIR analysis show the peak at 3400 1/cm that is due to the stretching of O-H bonds of both MOFs. In the Zr-BDC-NH2, peak at 1378 1/cm represents the stretching of N-H bonds in the amino benzene-dicarboxylic or terephthalic acid linker. The surface areas of Zr-BDC and Zr-BDC-NH2 MOFs are 714 and 757 m2/g, respectively. We will utilize these MOFs as a sensor for HER2 protein, a biomarker of breast cancer.
Computational fluid dynamics analysis of the natural circulation system in vertical heater horizontal cooler (VHHC) molten salt loop
Authors: Hariyanto Duwi , Waris Abdul , Suprijadi
Published: June 2022

Molten salt has attracted the attention of researchers, especially as a coolant because of its characteristics. This study aimed to analyse the transient and steady-state of the natural circulation system in the molten salt loop with vertical heater and horizontal cooler using computational fluid dynamics. The computational fluid dynamics module in the COMSOL Multiphysics software was used to solve governing equations. Experimental data from several references were used as input data in modelling. The loop was modelled as a rectangular loop with Inconel 625 as the pipe material and molten salt (NaNO3+KNO3) as the working fluid. The variation of heater power was also carried out in modelling. The modelling results showed a good agreement with the experimental results. The results provided that the molten salt natural circulation loop with vertical heater and horizontal cooler showed good flow stability without reversal of flow direction.
The effect of Copper utilization on MSFR’s safety plug performance simulation by using MPS
Authors: Yanti Nita Juli , Mustari Asril Pramutadi Andi , Hidayati Anni Nuril , Aprianti Nur Asiah
Published: June 2022

Generation IV reactors are developed and expected to have a higher safety level than the previous reactors. One of the generation IV reactors is Molten Salt Fast Reactor (MSFR) with the freeze plug and drainage pipe as the integrated safety system. When an accident occurs, the fuel flows down, directly interacts and melts the freeze plug. Moreover, the fuel will be cooled at the safety tank. This research aims to simulate the freeze plug melting process by using Moving Particle Semi Implicit (MPS) method. MPS is a particle method based on Lagrangian mechanism developed by Koshizuka and Oka in 1996. Mainly, the freeze plug consisted of frozen salt and Hastelloy N. There were two kinds of freeze plug geometry used in the simulation, which were without and with copper. The copper thickness was varied between 1.5 - 3.0 mm with 0.5 mm intervals. The additional copper thickness was performed toward the inside of the freeze plug. The height and the radius of freeze plug were 30 mm. The thickness of Hastelloy N and the copper were 8.5 mm and 2.5 mm, respectively. S-curve temperature distribution was initially applied due to the heat transfer between molten salt and the freeze plug material. The results show the melting time of with and without copper cases were 125 s and 250 s, respectively. Moreover, the thicker copper led to the faster freeze plug melting process.
Implementation of LSD Fission Barrier in Fission Cross Section Calculations
Authors: Kurniadi Rizal
Published: June 2022

In this paper, the fission cross-sections of Th-232(n, f) and U-238(n, f) have been calculated using the fission barrier parameter obtained from Lublin-Strassbourg Drop Model (LSD) in the statistical model framework. This model has been derived from the modern liquid drop (NLD) by adding a first-order curvature term that depends on the deformation parameter. This term has resulted from the implementation of Leptodermous expansion of nuclear energy. The deformation function involved in LSD formulation is obtained from Funny Hills nuclear shape parameterization. The obtained results would be compared with another result calculated using ETFSI (Extended Thomas Fermi and Strutinsky Integral) method and experimental fission cross-section extracted from ENDF data.
Simple Qualitative Modelling of Particle Size Analysis using Ray Tracing Method
Authors: Yulita D , Putra M I R , Dini S U , Erlina  , Jessika  , Pradana A , Handayani M , Anshori I
Published: June 2022

Understanding particle size analysis is essential for pharmaceutical, mining, environmental, coatings, and other industries. Although there are numerous technologies that can be utilized to take particle size measurements, the results of those measurements are presented automatically and are sometimes difficult to understand. In this study, using the ray-tracing method, simple qualitative modelling of particle size analysers can be developed. The laser is positioned as the initial position of the light source in x and y directions. The cell is pictured by cuvettes with four surfaces clear, and the particle is modelled as a sphere. Reflection of a single ray of the laser beam on many spheres can be performed using single ray reflection on a single sphere consecutively until the beam leaving the observation region or arriving at a light sensor. Then with vector formulation of ray direction after reflection on many spheres system

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Study of Lysine and Asparagine as Capping Agent for Gold Nanoparticles
Authors: Tsalsabila A , Herbani Y , Sari Y W
Published: June 2022

The wide application of gold nanoparticles has attracted much attention to the development of research in gold nanoparticles. In this study, the gold nanoparticles were prepared by chemical reduction method using potassium tetrachloroaurate as the gold source and sodium borohydride as reducer agent. The formation of gold nanoparticles was confirmed by surface plasmon spectra in ultraviolet-visible spectroscopy at wavelength 507 nm. The capping process of gold nanoparticles was studied using two different charges of amino acids. The asparagine had used as uncharge amino acid and lysine as a positive charge amino acid. The redshift in surface plasmon spectra showed the aggregation of the gold nanoparticles after being capped with amino acids that indicates the surface modification. The amine and carboxylate group was present on the gold nanoparticle surface after being capped with amino acids. The zeta potential results indicate the lysine capped gold nanoparticles have slightly higher stability than the asparagine capped gold nanoparticles. These stability and surface modification of gold nanoparticles are expected to increase their utilization on biological and medical applications.
DFT study of lithium diffusion in pristine La2O3
Authors: Lasiman E T , Naufal F D , Anshor M F , Syafira A Z F , Setianto D , Ubaidillah A , Rendy B , Komalig R W M , Nuruddin A , Saputro A G , Shukri G
Published: June 2022

Surface coating can suppress side reactions between electrode and electrolyte in Lithium-Ion Batteries (LIBs) but may also affect the Li mobility when shuttling into / out from the electrode of a LIB. Lanthanum Oxide (La2O3) coating has been experimentally shown to enhance LIB performance. In this study, we investigate the diffusion of Li in pristine La2O3 to understand the enhanced electrochemical performance of several La2O3-coated Li-ion battery cathodes. We used Density Functional Theory (DFT) with Climbing Image Nudged Elastic Band (CI-NEB) to calculate the energy barrier and the diffusivity of Li. We considered three pathways, i.e., the octahedral-to-octahedral path (O-O), octahedral-tetrahedral-octahedral path (O-T-O), and octahedral-tetrahedral-tetrahedral-octahedral path (O-T-T-O), and our results suggest that the O-O pathway has the lowest Li energy barrier of 0.09 eV. This finding suggests that Li will preferably diffuse along the [010] direction. Furthermore, we find that Li will diffuse more slowly along the [001] direction.
Anomaly Detection of Gas-Insulated Switchgear (GIS) Equipment Based on Embedding Position Variational Auto-Encoder
Authors: Jie Mei , Ming Zhu , Yongka Qi , Ming Fu , Hui Xu , Dexin Nie , Yongxiang Li
Published: June 2022

Gas-insulated switchgear (GIS) is one of the most important power devices in the power system. Once a fault occurs, it is difficult to determine and locate the fault due to its fully enclosed nature, which may lead to greater accidents and huge losses. Many GIS anomaly detection methods based on vibration and deep learning (DL) have been developed in recent years. However, these DL-based methods only utilize one single sampling point data on GIS, while not all faults are reflected at the points currently in use due to the signal attenuation. In this paper, an embedded position variational auto-encoder (EP-VAE) model for anomaly detection of GIS devices is presented, which can model multipoint vibration signals. We fuse the position information and the corresponding one dimension vibration signal to the two dimension grayscale images by Gram matrix. Then, the normal grayscale images are feed into the EP-VAE model, which is optimized by KL divergence and reconstruction error jointly. In the test phase, when one of these two losses is higher than the normal images, it is identified as an abnormal fault. We use the vibration data from the actual operation of GIS to carry out the anomaly detection experiments. The results show that our model EP-VAE has a detection accuracy of 93.12% for normal vibration grayscale images, and an abnormality detection accuracy of 87.94%.
Evacuation Simulation of Large Theater Based on Pyrosim and Pathfinder
Authors: Zhang Hui , Miao Zhi-hong , Lv Hong-ni , Leng Zhi-ling
Published: June 2022

Large-scale theaters with dense personnel are novel and unique, but there are many potential hidden dangers. Once an unexpected accident or disaster occurs, it is easy to cause crowd panic, and leads to congestion of evacuation path, aggravation of evacuation difficulty, crowding, stampede, and other group injuries. Therefore, studying the architectural characteristics of large theaters and evacuation behavior under fire can provide reference for the evacuation of such buildings and the preparation of emergency plans. This study took a large theater that can accommodate more than 1500 people as the research object, built a 3D model based on BIM, used Pyrosim and Pathfinder simulation software to simulate the smoke diffusion and personnel evacuation in the case of the building fire, observed whether all personnel could evacuate within the safe evacuation time, and analyzed the existing problems in the evacuation process. According to the results, it was difficult to evacuate due to the high crowd density and complex composition of large theaters. In short, appropriately increasing the width of evacuation doors and ensuring the normal operation of firefighting facilities can ensure the safe evacuation of personnel.