bluuebunny/crossref_metadata_2025 huggingface dataset:
Bistability analysis of opposed jet combustor under cold and reacting flow conditions
Authors: Sharon Ariel , Levy Yeshayahou
Published: March 2021

Opposed Jet Combustor (OJC) is a widely used layout to study and measure flame properties. The fundamental assumption of the counterflow configuration is that the flow is steady and quasi-one-dimensional. In principle, OJC stagnation planes are generated when two streams of opposing follow impinge against the other. The characteristic of such formed stagnation zone is a function of momentum balancing. But a detailed analysis shows that the flow regime developed in OJC is much more complex. It is seen that for the same set of boundary conditions, the stagnation plane can exist at more than one axial location, thereby showcasing the phenomenon of bistability. In this work, a conical opposed jet combustor producing a flat nozzle exit velocity profile was employed to study this phenomenon of bistability under isothermal and reacting flow conditions. The flow field impingement region was analyzed in search of instabilities and asymmetries. Phase Doppler particle analyzer, camera, and thermocouple measurements were employed to map this asymmetric behavior. The result showcases that the axisymmetric cold flow exhibits three flow regimes, i.e., (1) single symmetric, (2) steady-state multiplicity, and (3) time-dependent unsteady state. More importantly, the bistability has been conclusively witnessed even during combustion experiments. This bistable branching observed during combustion was different from that of cold flow. With the reacting flow, the bistable planes showcase different degrees of stability, with only one plane being stable. The results observed here showcase the need to consider the possibility of bistability even during combustion experiments.
Maxwell relation, giant (negative) electrocaloric effect, and polarization hysteresis
Authors: Chen Xin , Li Siqi , Jian Xiaodong , Hambal Yusra , Lu Sheng-Guo , Shvartsman Vladimir V. , Lupascu Doru C. , Zhang Q. M.
Published: March 2021

The electrocaloric effect (ECE) in dielectrics is characterized by the isothermal entropy change ΔS and adiabatic temperature change ΔT induced by changes of external electric fields. The Maxwell relation, which relates changes of polarization P with temperature T (pyroelectric coefficient) under a fixed electric field E to ΔS for finite intervals in E, provides a convenient way to deduce the ECE from polarization data P(T, E). Hence, this method, known as the indirect method, is widely used in ECE studies in ferroelectrics. Here, we first present the thermodynamic consideration for the Maxwell relation. We then use the indirect method and P(T, E) from bipolar and unipolar polarization curves to deduce the ECE in the normal ferroelectric phase of a P(VDF-TrFE) copolymer. The deduced ECE using the P(T, E) from bipolar polarization curves exhibits a giant negative ECE. In contrast, the directly measured ECE in the same polymer shows the weak and normal ECE. We discuss the constraints of the indirect method and its relation to the polarization–electric field curves measured in practical ferroelectric materials.
Instability of ultrathin viscoelastic freestanding films
Authors: Sekhar Satya , Shankar V.
Published: March 2021

The linear stability of freestanding thin films under the influence of attractive van der Waals forces is investigated for three rheological models, viz., Newtonian viscous films, viscoelastic solid films, and Jeffreys viscoelastic liquid films, with the aim of studying the role of rheology on the instability. Thin freestanding viscous films are unconditionally unstable, whereas the shear modulus in thin freestanding solid viscoelastic films governs the onset of instability. Interestingly, elasticity plays a dual role with regard to the stability of freestanding solid and liquid films: while it has a stabilizing influence on the former, it is destabilizing in the latter. Linear stability results of Jeffreys viscoelastic freestanding films are compared with those from supported films in the inertialess limit. The instability of Jeffreys viscoelastic freestanding film is unaffected by the relaxation time, but is enhanced with decrease in the viscosity ratio (μr, the ratio of solvent viscosity to total viscosity). The dominant length scale of instability in Jeffreys viscoelastic freestanding film shifts toward shorter wavelengths with decrease in μr. For μr→0, the maximum growth rate remains bounded in a freestanding viscoelastic film in the presence of inertia, but diverges in its absence, similar to supported viscoelastic films. In general, our results show that freestanding thin films exhibit faster dynamics than supported thin films. The mode of deformation of the freestanding film (viz., bending or squeezing) is not imposed a priori in our analysis and is found to be a squeezing (symmetric) mode with equal amplitudes at the interfaces.
A convolutional strategy on unstructured mesh for the adjoint vector modeling
Authors: Xu Mengfei , Song Shufang , Sun Xuxiang , Zhang Weiwei
Published: March 2021

In machine learning for fluid mechanics, the fully connected neural network (FNN) only uses local features for modeling, while the convolutional neural network (CNN) cannot be applied to data on structured/unstructured mesh. In order to overcome the limitations of the FNN and CNN, the unstructured convolutional neural network (UCNN) is proposed, which aggregates and effectively exploits the features of neighbor nodes through the weight function. Adjoint vector modeling is taken as the task to study the performance of the UCNN. The mapping function from flow-field features to the adjoint vector is constructed through efficient parallel implementation on graphics processing unit (GPU). The modeling capability of the UCNN is compared with that of the FNN on the validation set and in aerodynamic shape optimization in the test case. The influence of mesh changing on the modeling capability of the UCNN is further studied. The results indicate that the UCNN is more accurate in the modeling process.
Elastic instabilities and bifurcations in flows of wormlike micellar solutions past single and two vertically aligned microcylinders: Effect of blockage and gap ratios
Authors: Khan Mohd Bilal , Sasmal C.
Published: March 2021

This study presents an extensive numerical investigation on the flow characteristics of wormlike micellar (WLM) solutions past a single and vertically aligned two microcylinders placed in a microchannel in the creeping flow regime. The rheological behavior of the micellar solution is realized based on the two-species Vasquez–Cook–McKinley (VCM) constitutive model, which takes into account both the breakage and re-formation dynamics of micelles. For the case of single microcylinder, as the blockage ratio (ratio of the cylinder diameter to that of the channel height) is gradually varied, we find the existence of a flow bifurcation in the system, and also a gradual transition for a range of flow states, for instance, steady and symmetric or Newtonian like, steady and asymmetric, unsteady periodic and asymmetric, unsteady quasi-periodic and asymmetric, and, finally, unsteady quasi-periodic and symmetric. For the case of two microcylinders, we observe the presence of three distinct flow states in the system, namely diverging (D), asymmetric-diverging (AD), and converging (C) states as the intercylinder spacing in between the two cylinders is varied. Similar types of flow states are also observed in the recent experiments dealing with WLM solutions. However, we show that either this transition from one flow state to another in the case of a single microcylinder or the occurrence of any flow state in the case of two microcylinders is strongly dependent upon the values of the Weissenberg number and the nonlinear VCM model parameter ξ, which basically indicates how easy or hard it is to break a micelle. Based on the results and discussion presented herein for the single and two microcylinders, we hope this study will facilitate the understanding behind the formation of preferential paths or lanes during the flow of viscoelastic fluids through a porous media, which was seen in many prior experiments in the creeping flow regime.
Modal extraction of spatiotemporal atomization data using a deep convolutional Koopman network
Authors: Leask S. B. , McDonell V. G. , Samuelsen S.
Published: March 2021

Recent deep learning extensions in Koopman theory have enabled compact, interpretable representations of nonlinear dynamical systems that are amenable to linear analysis. Deep Koopman networks attempt to learn the Koopman eigenfunctions that capture the coordinate transformation to globally linearize system dynamics. These eigenfunctions can be linked to underlying system modes that govern the dynamical behavior of the system. While many related techniques have demonstrated their efficacy on low-dimensional systems and their associated state variables, in this work the system dynamics are observed optically (i.e., spatiotemporal data from video or simulation). We demonstrate the ability of a deep convolutional Koopman network (CKN) in automatically identifying independent modes of simple simulated and atomization systems. Practically, the CKN allows for flexibility in system data collection as the data can be easily obtainable observable variables. The learned models are able to successfully and robustly identify the underlying modes governing the system, even with a redundantly large embedding space. Modal disaggregation is encouraged using a simple masking procedure. All of the systems analyzed in this work use an identical network architecture and results are more compact and interpretable compared to dynamic mode decomposition.
Phylogenomics and biogeography of leptonetid spiders (Araneae : Leptonetidae)
Authors: Ledford Joel , Derkarabetian Shahan , Ribera Carles , Starrett James , Bond Jason E. , Griswold Charles , Hedin Marshal
Published: March 2021

Leptonetidae are rarely encountered spiders, usually associated with caves and mesic habitats, and are disjunctly distributed across the Holarctic. Data from ultraconserved elements (UCEs) were used in concatenated and coalescent-based analyses to estimate the phylogenetic history of the family. Our taxon sample included close outgroups, and 90% of described leptonetid genera, with denser sampling in North America and Mediterranean Europe. Two data matrices were assembled and analysed; the first ‘relaxed’ matrix includes the maximum number of loci and the second ‘strict’ matrix is limited to the same set of core orthologs but with flanking introns mostly removed. A molecular dating analysis incorporating fossil and geological calibration points was used to estimate divergence times, and dispersal–extinction–cladogenesis analysis (DEC) was used to infer ancestral distributions. Analysis of both data matrices using maximum likelihood and coalescent-based methods supports the monophyly of Archoleptonetinae and Leptonetinae. However, relationships among Archoleptonetinae, Leptonetinae, and Austrochiloidea are poorly supported and remain unresolved. Archoleptonetinae is elevated to family rank Archoleptonetidae (new rank) and Leptonetidae (new status) is restricted to include only members of the subfamily Leptonetinae; a taxonomic review with morphological diagnoses is provided for both families. Four well supported lineages within Leptonetidae (new status) are recovered: (1) the Calileptoneta group, (2) the Leptoneta group, (3) the Paraleptoneta group, and (4) the Protoleptoneta group. Most genera within Leptonetidae are monophyletic, although Barusia, Cataleptoneta, and Leptoneta include misplaced species and require taxonomic revision. The origin of Archoleptonetidae (new rank), Leptonetidae, and the four main lineages within Leptonetidae date to the Cretaceous. DEC analysis infers the Leptoneta and Paraleptoneta groups to have ancestral distributions restricted to Mediterranean Europe, whereas the Calileptoneta and Protoleptoneta groups include genera with ancestral distributions spanning eastern and western North America, Mediterranean Europe, and east Asia. Based on a combination of biology, estimated divergence times, and inferred ancestral distributions we hypothesise that Leptonetidae was once widespread across the Holarctic and their present distributions are largely the result of vicariance. Given the wide disjunctions between taxa, we broadly interpret the family as a Holarctic relict fauna and hypothesise that they were once part of the Boreotropical forest ecosystem.
Investigating the relationships between soil acidity and phosphorus fractions in high country farmland of New Zealand’s South Island
Authors: Hendrie Daniel L. , Moir Jim L. , Boitt Gustavo , Simpson Zachary P. , Condron Leo M.
Published: March 2021

Soil fertility remains a limitation to pasture production in the South Island high country of New Zealand, despite a strong history of aerial superphosphate fertiliser applications. This may in part be due to the acidic nature of these soils. This study of extensively farmed high country soils (n = 19) aimed to investigate the current status of soil fertility, and to quantify the effects soil acidity and exchangeable aluminium (Al) have on the accumulation of phosphorus (P) in these soils. To a depth of 7.5 cm, mean soil pHH2O across these soils was 5.2 ± 0.1, and exchangeable Al concentrations increased exponentially as pH decreased (R2 = 0.87), exceeding 3 mg kg–1 at pHH2O ≤ 5.1. Sulfur (S) concentrations were highly deficient for pasture production in these high country soils, with sulfate S (SO4-S) and organic S (Org-S) only exceeding 10 mg kg–1 at 6 and 3 out of the 19 sites, respectively. Total soil P concentrations, measured by Hedley fractionation, ranged from 587 to 1570 mg P kg–1, but only 7.2 ± 0.5% of this P was plant-available P (20.1–152 mg P kg–1). The greatest concentrations of P that these soils contained were in the moderately-labile organic P fraction (176–730 mg P kg–1), which may have the potential to become available due to organic matter mineralisation following liming. However, using Pearson’s correlations and principal component analysis, no strong correlations between the quantities or proportions of P contained in each P fraction were found due to the acidity or concentrations of exchangeable Al in these soils. This suggests that liming these soils is unlikely to result in substantial increases in plant P availability from the mineralisation of P in non-labile soil P fractions.
Inflammatory signaling sensitizes Piezo1 mechanotransduction in articular chondrocytes as a pathogenic feed-forward mechanism in osteoarthritis
Authors: Lee Whasil , Nims Robert J. , Savadipour Alireza , Zhang Qiaojuan , Leddy Holly A. , Liu Fang , McNulty Amy L. , Chen Yong , Guilak Farshid , Liedtke Wolfgang B.
Published: March 2021

Significance

Osteoarthritis is a global health problem that affects load-bearing joints, causing loss of mobility and enormous healthcare costs. However, disease-modifying approaches are lacking. Here, we report a cellular mechanism of inflammatory signaling in chondrocytes, the cellular component of cartilage. We show how osteoarthritis-relevant levels of interleukin-1α reprogram articular chondrocytes so that they become more susceptible to mechanical trauma, which chondrocytes sense via Piezo1/2-mechanosensitive ion channels. We uncover that IL-1α enhances gene expression of
P
iezo
1
in primary articular chondrocytes underlying Piezo1 enhanced function. We elucidate signaling from membrane to nucleus, including transcription factors that enhance Piezo1 expression. We also define consequences of increased expression of Piezo1, for mechanotransduction and at rest, that implicate this reprogramming mechanism in osteoarthritis pathogenesis.
Health and economic impact of the pneumococcal conjugate vaccine in hindering antimicrobial resistance in China
Authors: Lu Ember (Yiwei) , Chen Hui-Han , Zhao Hongqing , Ozawa Sachiko
Published: March 2021

Significance

This study offers a comprehensive and scientifically grounded quantitative model predicting the broader economic value of pneumococcal vaccination (PCV) in slowing the development of antimicrobial resistance (AMR) in China. China has high antibiotic use and low PCV coverage, making it an important country to assess in addressing AMR. Based on current published evidence, this model shows that introducing PCV in China’s national immunization program would likely save lives and bring wider societal benefits by reducing antibiotic utilization and treatment failures due to AMR.
Tissue-resident memory T cells in tumor immunity and immunotherapy
Authors: Okła Karolina , Farber Donna L. , Zou Weiping
Published: March 2021

Tissue-resident memory T cells (TRM) represent a heterogeneous T cell population with the functionality of both effector and memory T cells. TRM express residence gene signatures. This feature allows them to traffic to, reside in, and potentially patrol peripheral tissues, thereby enforcing an efficient long-term immune-protective role. Recent studies have revealed TRM involvement in tumor immune responses. TRM tumor infiltration correlates with enhanced response to current immunotherapy and is often associated with favorable clinical outcome in patients with cancer. Thus, targeting TRM may lead to enhanced cancer immunotherapy efficacy. Here, we review and discuss recent advances on the nature of TRM in the context of tumor immunity and immunotherapy.
The architectural design of CD8+ T cell responses in acute and chronic infection: Parallel structures with divergent fates
Authors: Chung H. Kay , McDonald Bryan , Kaech Susan M.
Published: March 2021

In response to infection, T cells adopt a range of differentiation states, creating numerous heterogeneous subsets that exhibit different phenotypes, functions, and migration patterns. This T cell heterogeneity is a universal feature of T cell immunity, needed to effectively control pathogens in a context-dependent manner and generate long-lived immunity to those pathogens. Here, we review new insights into differentiation state dynamics and population heterogeneity of CD8+ T cells in acute and chronic viral infections and cancer and highlight the parallels and distinctions between acute and chronic antigen stimulation settings. We focus on transcriptional and epigenetic networks that modulate the plasticity and terminal differentiation of antigen-specific CD8+ T cells and generate functionally diverse T cell subsets with different roles to combat infection and cancer.
Eliminating the LIGO bounds on primordial black hole dark matter
Authors: Bœhm Céline , Kobakhidze Archil , A.J. O'Hare Ciaran , S.C. Picker Zachary , Sakellariadou Mairi
Published: March 2021

Primordial black holes (PBHs) in the mass range (30–100) M⊙ are interesting candidates for dark matter but are tightly constrained by the LIGO merger rate. In deriving these constraints, PBHs were treated as constant Schwarzschild masses. A careful analysis of cosmological black holes however leads to a time-dependent effective mass. This implies stricter conditions for binary formation, so that the binaries formed merge well before LIGO's observations. The observed binaries are those coalescing within galactic halos, at a rate consistent with LIGO data. This reopens the possibility of LIGO mass PBH dark matter.
Local time of an Ornstein–Uhlenbeck particle
Authors: Kishore G , Kundu Anupam
Published: March 2021

In this paper, we study the local time spent by an Ornstein–Uhlenbeck (OU) particle at some location till time t. Using the Feynman–Kac formalism, the computation of the moment generating function (MGF) of the local time can be mapped to the problem of finding the eigenvalues and eigenfunctions of a quantum particle. We employ quantum perturbation theory to compute the eigenvalues and eigenfunctions in powers of the argument of the MGF which particularly help to directly compute the cumulants and correlations among local times spent at different locations. In particular, we obtain explicit expressions of the mean, variance, and covariance of the local times in the presence and in the absence of an absorbing boundary, conditioned on survival. In the absence of absorbing boundaries, we also study large deviations of the local time and compute exact asymptotic forms of the associated large deviation functions explicitly. In the second part of the paper, we extend our study of the statistics of local time of the OU particle to the case not conditioned on survival. In this case, one expects the distribution of the local time to reach a stationary distribution in the large time limit. Computations of such stationary distributions are known in the literature as the problem of first passage functionals. In this paper, we study the approach to this stationary state with time by providing a general formulation for evaluating the MGF. From this MGF, we compute the cumulants of the local time exhibiting the approach to the stationary values explicitly for a free particle and a OU particle. Our analytical results are verified and supported by numerical simulations.
Profitability of a hybrid heating system for a single-family house in Poland based on a heat pump and photovoltaics
Authors: Drzymała A , Korzeniewska E
Published: March 2021

The article presents an analysis of the profitability of an investment consisting of a heat pump and a photovoltaic installation located in Poland for an exemplary single-family house. The factors that have a significant impact on the profitability and payback time of such installations operating in a dual configuration are described. A simulation of profitability taking into account the legal regulations and support systems was presented. The considered case of profitability concerns a specific technical solution in which an 8 kW air / water pump was used. The pomp cooperates with a photovoltaic installation with a power of up to 10kW, operating in a discount system with an energy consumption factor of 0.8. For the purposes of this article, the DCF (discounted cash flow) method was used. Using this method, it is possible to calculate the market value of the investment with the assumed boundary criteria. A comparison of the economic efficiency of an investment can be presented using the IRR (internal rate of return) method.
Modification of pigments content in red clover sprouts with the use of pulsed electric field
Authors: Gałązka-Czarnecka I , Korzeniewska E , Czarnecki A , Stańdo J
Published: March 2021

An innovative issue in food engineering is using the impulse electric field (PEF) in modeling the content of biologically active compounds in plant raw materials, including seeds. In the described experiment it was shown that it is possible to modify the carotenoid content in germinating seeds of red clover (Trifolium pratense L.) by treating the seeds with PEF before cultivation. The research material was the seeds of red clover ‘Rozeta’ variety. As a result of the conducted research, an increase in the content of lutein and zaaxanthin by 10% and β-carotene by 16% was obtained after the sprouts were subjected to a field of 5 kV/cm intensity.
Current and future energy refilling stations in motor vehicles, problems and effects of replacing internal combustion vehicles with electric ones
Authors: Kaznowski R , Sztafrowski D
Published: March 2021

The paper deals with changes in construction and operation that would have to take place at a petrol station located in Wroclaw next to one of the shopping malls in the event of replacing internal combustion vehicles with electric ones. In addition, it was estimated to what extent the photovoltaic panels placed on the gallery roof can relieve the energy supplier’s network. By modeling the expected electric vehicle system in the years 2025-2030, efforts were made to identify potential barriers to its operation on the assumed scale by referring to the operation of electromobility in countries where this system became popular. The launch of a group of a dozen large charging stations in the city will allow the operation of the electric vehicle system in the amount assumed for the years 2025 - 2030, but will force a significant demand for electricity. Generation of electricity from RES will be enough to meet the needs of charging electric vehicles in Poland in the assumed time horizon, ie until 2040. Demand for vehicle charging power may cause problems with its availability in the system in the absence of implementation of the incentive system for vehicle charging off-peak hours.
Response of potato starch granules to microwave radiation
Authors: Miernik A , Jakubowski T
Published: March 2021

This study aimed to determine the response of potato starch granules to microwave radiation indicated by changes in starch granule size. Laboratory analyses were carried out in 2019 with tubers of an early edible potato cultivar Innovator. The tubers were irradiated for 10-600 s using a 100 W generator producing microwaves having a frequency of 2.45 GHz. Dimensions of starch granules were measured using an OPTICA B-510BF optical microscope and PROVIEW x64 software, 3.7.13483.20181206. The results were analyzed in STATISTICA 13.3. software package at a significance level of α=0.05. The microwaves were shown to significantly modify the maximal diameter and surface area of potato starch granules.
Selected methods for starch content determination in plant materials
Authors: Miernik A , Jakubowski T
Published: March 2021

This manuscript presents selected analytical methods for starch content determination in plant materials. The presentation includes tools and equipment needed to apply a selected method and method accuracy in determinations of starch content and parameters. An overview of these methods may be useful while designing studies focused on starch content in materials of plant origin. The manuscript also discusses the effect of microwave radiation on selected parameters of starch granules. In addition, it presents results of an experiment aimed at determining the response of potato starch granules to microwave radiation. In that experiment, the size of potato granules was measured using an OPTICA B-510BF optical microscope and PROVIEW x64 software, 3.7.13483.20181206. The results obtained were analyzed at a significance level of α=0.05 using STATISTICA 13.3 software package.
Physical and rheological properties of liquid whole egg after treatment of concentrated microwave field (CMF)
Authors: Oziemblowski M , Nawirska-Olszańska A , Maksimowski D , Trenka M
Published: March 2021

The influence of selected physical and rheological properties of the egg mass after the treatment of concentrated microwave field (CMF) was analysed in the study. CMF treatment can be generated in the continuous or pulsed way where microwave field is concentrated by a special waveguide. The raw material for the research was fresh hen eggs obtained from Leghorn Brown laying hens at the age of 30-50 weeks. The study investigated the effect of CMF pulses on the raw material, where the variable parameters were intervals between single pulses of 0.5 s, 1.0 s or 1.5 s, as well as 3 different numbers of CMF pulse packets for each of these intervals (5, 7 or 9). In this way, 9 research variants were obtained, not counting the control sample. After completion of the CMF treatment, the temperature of the samples was measured, and then they were cooled down to the temperature of 20 °C, where the analysis of active acidity (pH), color measurements expressed as L*a*b* and viscosity was performed. The results were statistically processed using the analysis of variations, Duncan’s test and the so-called “Response Surface Methodology” with corresponding Pareto charts showing the significance of the analyzed variables and their interactions. It was found that both the amount of energy supplied to the system and the intervals between the CMF pulses for most of the analyzed parameters had a statistically significant effect. The “response surface” models may have practical application, eg in industrial conditions, in determining the impact of individual technological parameters on the final quality of food products, including physical and rheological characteristics.
Structure analysis of the thermal energy spectrum generated during stimulation of organic matter by an electromagnetic field
Authors: Popardowski E , Kiełbasa P , Dróżdż T. , Rad M
Published: March 2021

The article presents the spectral characteristics of the temperature distribution in an induction coil which is an actuator in the technology of electromagnetic stimulation of organic matter and in the technology of elimination of undesirable microorganisms. The rate and method of heating the coil were precisely determined depending on the magnitude of the magnetic induction and the stimulation time of the material as well as the amount of flow of the coil cooling agent. Based on the experiment, the structure of the exposure time and the structure of the distribution of biological material in the working part of the coil were determined. Furthermore, the degree of cooling was determined so as to eliminate the uncontrolled momentary temperature amplitude on the course of the organic matter stimulation process.
Survey identification of impact the 50 Hz magnetic field on selected biochemical parameters of human blood
Authors: Sztafrowski D , Jakubaszko J
Published: March 2021

The paper presents the influence of 50 Hz magnetic field on selected biochemical parameters of human blood. The analysis was carried out in test environment created in the department of Electrical Power Engineering at Wroclaw University of Science and Technology, using magnetic field of 50 Hz, with values and homogeneity equivalent to these of electrical power objects. The study was conducted in collaboration with the Wroclaw Medical University.
Analysis of digital simulation of electrical fields intensity by using central differences of second or fourth order
Authors: Sztafrowski D , Gumiela J
Published: March 2021

For the computational identification of the intensity of the electric component of the electromagnetic field, methods are used in which the differential description describing of a spatial distribution of the potential is converted and then presented as the difference description. Depending on the number of terms of the series corresponding to the function searched for in the difference method, the value of each grid point can be determined by standard using the central difference of the second or fourth order. For the selected case of the 220 kV overhead powerline, the authors compared the influence of the applied order of the central difference on the calculation time and the value of the maximum relative error of the simulation.
Improving vehicle routing decision for subsidized rice distribution using linear programming considering stochastic travel times
Authors: Nurprihatin Filscha , Regent Montororing Yuri Delano
Published: March 2021

As the highest regency with the absolute poverty rate in Indonesia, Bogor Regency must be able to handle the poverty program appropriately and ensure its effectiveness and efficiency. Subsidized rice is one of the government programs for poor households. This program is important because rice is a food commodity with the largest contribution to the food poverty line. The effectiveness of the distribution is very dependent on the accuracy of the target number of beneficiaries and the accuracy of the amount of rice received at the consumption points. Meanwhile, the distribution efficiency is measured from the distribution route by taking into account the travel time that is directly related to transportation costs. This study discusses the distribution from only 1 (one) warehouse to 57 destinations. This study contributes to the enrichment of a cluster first route second approach to solve the routing problem. This paper applies Ward’s method and K-Means sequentially which generates 4 (four) clusters. Linear programming under the Capacitated Vehicle Routing Problem model is utilized to generate the routing decisions. Clusters 1 and 3 must take 1 and 2 trips, respectively. Meanwhile, clusters 2 and 4 each take 3 trips. As a result, the proposed method ensures all trips consume the shortest time.
Optimizing rice distribution routes in Indonesia using a two-step linear programming considering logistics costs
Authors: Nurprihatin Filscha , Regina Tasya , Rembulan Glisina Dwinoor
Published: March 2021

The increase in rice consumption should be balanced with an increase in rice production. However, although the national rice production was declared a surplus, the volume of national rice imports also increased. The imports in 2018 were 2.2 million tons and showed that surplus rice production is not effectively taken as an advantage in overcoming the deficit in some provinces in Indonesia. Some provinces that experiencing surplus should be able to fill the shortage in the other provinces. This paper contributes to determine distribution routes and help the government to fulfill the shortage demand. This study uses the two-steps linear programming method. The first step is performed by the transportation model and followed by the Capacitated Vehicle Routing Problem (CVRP) model in sequence. This two-step linear programming reaches an optimal global solution in distributing goods from oversupply provinces to the over-demand one. The results show cost savings are gained if this strategy is performed to meet the demand, rather than importing the rice.
Design of big data technology prototype for classification of village status based on village development index involves k-means algorithm to support village ministry Pdtt work programs
Authors: Hasugian Paska Marto , Hutahaean Harvei Desmon , Sinaga Bosker , Sriadhi  , Silaban Saronom
Published: March 2021

Big data technology is the overall technology that can handle the processing associated with analyzing the data to explore the potential that is in it. Some of the uses of big data are based on the biggest data traffic sources, such as social media, financial transactions, public data, censorship data, and company data. The problem found in the accumulation of village status data that has not been utilized in the decision-making process to determine the status of the next village and the absence of an application to process the data stored in the data database so that a tool is developed to analyze the buildup. The results of this study are to produce a prototype design that is Unified Modeling Language (UML) design, Form Design, and Database Design that will be used to develop Big Data Technology in determining the classification of village status based on the Village Build index.
Feasibility Analysis Test of Computer Based Testing (CBT) System for General Physics Exam
Authors: Abubakar  , Tanjung Yulifda , Wulandari Dewi
Published: March 2021

This study aims to develop and to test the feasibility of Computer Based Testing (CBT) system for General Physics courses that can be used as a media to measure the ability of student. This research involves a part of Research and Development (R & D) for developing CBT product and also descriptive research for qualitative and quantitative data processing. The collected data as a result of assessment are validated by a team who are experts in analyzing qualitatively and quantitatively. The procedure of implementation consists of three stages, namely preparation, implementation and final stages. In the preparation stage, the CBT system is accommodated in preparing application and all items. In the implementation stage, the feasibility test is conducted through an assessment supported by IT Expert Team. In the final stage, the assessment results of the IT Expert Team are used as a basis for evaluating the CBT system. As result, the Computer Based Testing (CBT) system has fulfilled the criteria of question eligibility through content validity testing with aspects of matter, construction and language. The average value is 75.6 that satisfy valid criteria with minor revisions as well as satisfy eligibility system which includes Content, Interface, Navigation and Security indicators with the percentage is 86.6% involving the category of the level of eligibility which is in very good level. Thus, it can be used as a medium for student exams in the General Physics course.
Development Environment of Machine Learning for Image Classification
Authors: Tarigan Irwan Jani , Sihombing Poltak , Sirait Pahala
Published: March 2021

Machine learning is an interesting topic nowadays, it is also a subarea of artificial intelligence. An interesting thing that needs to be done in the beginning is how to configure the Development Environment (DE). In this paper, DE is configured using Acer-Notebook with jupyter notebook and Smartphone with google colab for image classification using convolution neural network method. The configuration process is easier to do on Smartphone Realme-C2 than Acer-Notebook and the best level of accuracy is epoch 100 in training and testing data obtained by Smartphone Realme-C2 are 0.70 and 0.66, while Acer-Notebook is 0.70 and 0.63.
Effectiveness of typha latifolia for phytoremediation of cadmium in acid mine drainage
Authors: Putri Maharani Permata , Moersidik Setyo Sarwanto
Published: March 2021

One evidence of environmental pollution is the formation of acid mine drainage. In passive processing systems, the technique that is often used is phytoremediation because the costs incurred for this method are affordable and take advantage of natural ecosystems. In this study, the effectiveness of Typha latifoliain neutralizing acidity and removing heavy metal such as cadmium (Cd) is determined. Cadmium is one of the heavy metals that can be found in nickel, gold, and copper mining area. The acid mine drainage used in this study was artificially made with a concentration of 5and 10 mg/L with a pH of 4.pH testing was carried out using a pH meter and the accumulation concentration of Cd was analyzed using Atomic Absorption Spectrophotometer (AAS). The results revealed that Typha latifolia planted on soil without fertilizer could increase the pH of acid mine drainage containing heavy metal Cd from 4 to ± 7 within 28 days.Typha latifolia can reduce the concentration of Cd in artificial acid mine drainage with the removal efficiency of 95 - 96%. The value of the Bioconcentration Factorin Typha latifolia exposed to acid mine drainage with concentrations of Cd 5 and 10 mg/L are > 1000, which means that this plant has the potential to be a heavy metal hyperaccumulator in phytoremediation.
Enhance sensitivity of plastic optical fiber sensor by spiral configuration for body temperature applications
Authors: Arifin A , Amaliyah K R , Lebang A K , Hamrun N , Dewang S , Tahir D
Published: March 2021

In this study, sensors to measure body temperature were made using a macro bending method based on plastic optical fiber. Fiber optic sensors are made to form a spiral configuration on variations in diameter and bend number. The body temperature sensors are mounted on the elastic cloth and placed on the armpit. The light from the LED transmitted into an optical fiber sensor is affected by body temperature, so there is power loss in the sensor. Power loss cause light intensity decreases received by the phototransistor and differential amplifier. The power loss of the sensor and temperature measurement results will be displayed on the computer through the Arduino Uno microcontroller. The range of temperature used is 28°C - 42°C. The best sensor characteristic obtains at the spiral configuration in a diameter of 0 cm with some bending four bends and a range value of 0.421 V, sensitivity of 30.071 mV/°C, and resolution of 0.033°C. Plastic optical fiber is very suitable to be used as body temperature sensors because it can enhance sensitivity.
Impact of potential earthquake disasters in the areas located in zone lineaments and the surrounding areas
Authors: Barlian Edo , Tarigan Johannes , Nasution Zulkifli , Purwoko Agus
Published: March 2021

In supporting the objectives of the Urban Spatial Plan, it is necessary toconduct a study on the readiness for response to natural geological disasters, especially areas located in fault zones as one of the sources of earthquake disasters in order to reduce risks that will occur and prepare serious mitigation studies on disaster management with efforts prevention, risk reduction and increased community preparedness in facing disasters. Part of the Deli Serdang Regency is an area located in the fault zone, namely in the Pancur Batu District and part of the Namorambe District. Based on these conditions, it is necessary to observe the impact on the development of the area around the fault zone. The method used in this study is a quantitative method with survey research and what is needed is seismic hazard data which includes Peak Ground Acceleration (PGA), physical properties of rocks, slope, seismicity, earthquake risk level, frequency of earthquakes, population, productive land and regional capacity. The observation area is Deli Serdang district which consists of 22 (twenty two) districts. The results of the analysis show that some areas of Deli Serdang district are included in earthquake-prone areas based on regional typology, namely type D and type E with land stability in the unstable category, namely some Gunung Meriah sub-districts, some STM Hulu sub-districts, some Sibolangit districts, some sub-districts Kutalimbaru, part of Sibirubiru sub-district and part of STM Hilir sub-district. Areas affected by the earthquake disaster need to be supervised in land use in order to reduce the impact of disasters in the long term and mitigation in the event of a disaster by applying Zoning Regulation and Building Code.
Calculation of PWR Thorium Pin Cell Burnup and Isotope Prediction Using WIMSD-5B Code
Authors: Tukiran S , Surian P , Farisy Y
Published: March 2021

The amount of thorium in the world is very abundant and the benefits of using thorium as fuel for nuclear reactors such as PWR are increasingly widespread, so it needs to be analyzed. In the initial phase, the PWR pin cell fuel analysis was carried out using the WIMSD-5B code. The PWR ThO2-UO2 fuel in the cladding with the fuel assembly model 17 x 17 is analyzed by its fuel burn up, neutron flux and isotope composition after maximum operation. The pin cell model consisting of fuel, cladding and coolant with a square pitch of 12.6 cm are calculated using different libraries. Eigenvalues, neutron fluxes and isotope concentrations were compared with the PWR pin cell model to high burnup. The eigenvalues and flux neutron as a function of burnup are good, the maximum difference is within 7.41% and the mean absolute difference is less than 3.12 %. The best comparison of fission product isotope concentrations is to use the ENDFB7.1 library with Thorium fuel and is comparable to the uranium fuel reported in the literature. Data sources for actinides and fission products used infuel depletion calculations for thorium fuel are all documented.
Influence of Lightning Characteristics on Back Flashover in Extra High Voltage Transmission Line: A case study
Authors: Hardi Surya , Mirza F , Bukit Ferry R A , Rohana
Published: March 2021

Lightning is one of the primary sources that cause failure on over head transmission system. It can lead to the transmission line insulator to be over voltage. Commonly, transmissions lines are equipped with ground wire and consist of one or two ground wire which it is depending on tower construction. Over voltage on the transmission line can occur in two ways viz., direct lightning strike on phase line and ground wire produce propagating wave to both sides the phase line and result in damage on insulator. Direct lightning stroke on ground wire or the tower structure of transmission can cause phenomenon back flashover (BFO) on insulator. The lightning current characteristic is distinguished in lightning maximum current and steepness of lightning current. This paper discusses influence of in different lightning characteristics on BFO in extra high voltage transmission line in simulation using ATP draw. The lightning surge currents of IEC and VDE standards were injected to the ground wire and phase lines. As the implementation, this paper used the data of extra high voltage transmission line of 275 kV, Galang - Binjai, North Sumatra Province, Indonesia.
Investigation of burning rate on particullate matter emission factor of rice straw burning (case studi in lombok island, indonesia)
Authors: Hadi K A , Wardoyo A Y P , Naba A , Juswono U P , Budianto A
Published: March 2021

This study investigates the emission factor arising from the agriculture waste burning especially rice straw burning. This research is a preliminary study to look further about the health impacts that occur due to the biomass burning that often occurs in Lombok island. The Laboratory study has been conducted to quantify the emission factor that looks into different burning rate related to the real condition in the field to estimate the health impact. The burning rates were varied into three different burning conditions, namely fast burning (13 m/s), medium burning (9 m/s) and slow burning ( 4 m/s). The concentration of the particle emissions (PM10 and PM2.5) were measured using a Handheld Air Tester (Hinaway, model CW-HAT200S) and a Digital Dust Monitor (Kanomax, model 3443). The emission factor is quantified by the total particle concentration divided by the burned fuel. The result shows that the burning rate determines the particle emission factor. The fast burning produces the particles the lowest PM10 and highest PM2.5 emission factor otherwise the slow burning results in the particle particles the highest PM10 and lowest PM2.5 emission factor.
Economic Design of Substation Grounding Grid using ETAP Software: A Case Study of 2 x 500 MVA Galang Substation
Authors: Hardi Surya , Andira R , Nisja I , Octrialdi B , Pinem M
Published: March 2021

Substation grounding purpose is to secure the safety of personal that are in the vicinity and provide protection of the equipment when short circuit faults. The grounding grid design is an important factor in a substation for fulfilling standard requirements formulated by IEEE Std. 80. Commonly, substation grounding is grid configuration or combination of grid and rod. This study is designing a substation economically by considering the length of rod conductor used. Some grid configuration models were used for analyzing viz. rectangular shape, T-shape and L-shape. The models were compared with the existing design in the Galang substation for finding the minimum conductor length. The grid grounding of the Galang substation is the rectangular shape. By using ETAP package software, the important parameters in design substations such as step voltage, touch voltage for 50 kg body weight can be obtained. The parameters must fulfill the IEEE std. 80-2013 as a safety requirement for designing of the substation. From various configurations were applied, all the shapes models meet the IEEE Std. 80, but T-shape is the most economical design based on the conductor length used.
The Reaction Mechanism of Ring-opening Polymerization of ε-Caprolactone Using Bis(benzoylacetonato)zirconium(IV) Catalyst With PM3 Semi-Empirical Method
Authors: Dibiyantini Ratu Evina , Yusuf Muhammad
Published: March 2021

Acknowledged that polycaprolactone (PCL) is one of the prospective polymer category. This is due to PCL has a great mechanical properties, biodegradability, and excellent mixing ability with various other polymers. The effective technique to get PCL is through the ring opening polymerization (ROP) of caprolactone (ε-CL) using metal catalyst. The aims of this research was to determine a reasonable reaction mechanism of the ROP ofε-CL using bis(benzoylacetonato)zirconium(IV) chloride catalyst. In this investigation the PM3 semi-empirical method was assigned to calculate the monomer, intermediate structures, and polymer structure. Then, to compute and visualize geometry structure was employed by using the HyperChem 8.0 program. This software operates on the Windows 07 system. The calculation results imply that to get PCL using bis(benzoylacetonato)zirconium(IV) catalyst required a few steps i.e. coordination ε-CL in metal center, χ-CL deprotonation, the insertion of ε–CL, and propagation of the chain.