bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative study of state of charge estimation algorithms for Lithium-Ion Battery
Authors: Shamarova N , Komarnicki P , Wenge C
Published: March 2021

Batteries are known to have found full applications in industries ranging from small electronic devices, mobile phones to complex systems such as electric vehicles and energy storage systems. The last one is characterized by the presence of large batteries with more than hundreds or thousands of batteries, so the process of estimation of their parameters becomes even more critical, demanding and complex. The evaluation of the state of batteries should be understood as finding the exact value of the following values: state of charge, capacity and internal resistance. The last two parameters are used to assess the health of batteries, to find available power and amount of energy respectively. Estimation the state of charge remains one of the most difficult tasks in the study of battery conditions. It is also one of the most important parameters that affect the correct operation of the battery, namely reliability, safety, performance. The main task of this paper is to present methods for reliable testing and evaluation of lithium batteries under different scenarios and conditions.
Mathematical modeling of the sunflower cake grinding process
Authors: Shepelev A B , Priporov I E
Published: March 2021

The design of an improved sunflower cake grinder is proposed, which consists in the modernization of knives in knife blocks in the form of an Archimedes Arbelo curvilinear triangle with saw-edged teeth along the perimeter of the entire surface of the cutting edge. This will allow obtaining cake in a crumbled form, depending on the type of the farm animal by constructing a mathematical model that considers physical and mechanical properties of the material, which describes the dependence of its design parameters on the factors under study that affect the technological process of its production and thereby improve the grinding quality. The article presents the mathematical model that allows determining the optimal values of the design parameters of the improved grinder. The improved sunflower cake grinder allows reducing its specific energy consumption compared to series-produced ones without deteriorating the quality of the material and to increase its performance. Based on the experimental studies conducted, the improved sunflower cake grinder allows it to be used in technological lines for the production of mixed feed with its adding in a crumbled form. The obtained design parameters of the improved grinder will be used in the further modernization of series-produced grinders for concentrated feed produced by Russian enterprises for various types of farm animals, which will allow replacing imported concentrated feed with Russian ones and thereby not depend on them due to the current situation in the world.
Technology for prediction of salt deposition in oil production
Authors: Lenchenkova L E , Zainagalina L Z , Bulchaev N D , Kotenev Yu A , Bulyukova F Z , Safiullina A R
Published: March 2021

The formation of inorganic salts in the bottom-hole area leads to a deterioration of the reservoir filtration properties and a decrease in the productivity of oil wells. The conducted research shows that the decrease in rock permeability due to salt deposition during flooding mainly depends on the number of filtered pore volumes of the injected solution, the rate of injection, temperature, differences in pressure, initial permeability of the rock and the concentration of the solution. The development of an empirical formula for predicting salt deposits in the bottom-hole area and describing the dependence of rock permeability on these factors involves the use of reliable experimental and field data. The authors propose a method for determining the probability of precipitation of some inorganic salts in the well.
Data analysis of the corrosion protection performance of aminobenzene concentrations on 1070 aluminum alloy in dilute HCl solution
Authors: Loto Roland T. , Loto Cleophas , Daada Tobi
Published: March 2021

Gravimetric and statistical analysis was used to assess the protection performance of aminobenzene compound on 1070 aluminum alloy in 1 M HCl solution in volumetric concentrations of 2.5%, 5%, 7.5%, 10%, 12.5% and 15%. Data output shows aminobenzene performed poorly at lower concentrations (2.5% to 10% aminobenzene concentrations) with highest value of 61.3% at 10% concentration and 480 h of exposure time. However, at higher concentrations the corrosion and oxidation of the aluminium surface was effectively suppressed with peak value of 81.7% at 480 h of exposure. Aminobenzene inhibition performance was determined to be highly concentration dependent with limited variation with respect to observation time. Standard deviation data showed significant variation of protection performance data at lower aminobenzene concentrations due to variation of the protection performance data with respect to observation time and thermodynamic instability of the inhibition mechanism. At 12.5% and 15% aminobenzene concentration the standard deviation values visibly decreased due to improved inhibition performance. Data also showed that only 31.67% of the protection performance data is above 70% inhibition efficiency at margin of error of +8.32%. Data from analysis of variance shows inhibitor concentration is the only statistical relevant factor at 75.57% responsible inhibition output of aminobenzene on the aluminium alloy compared to observation time with statistical relevance value of 12.28%.
Biosynthesis of silver nanoparticles by cell-free extract from Trichoderma reesei - study on the influence of growth media
Authors: Gemishev O Ts , Panayotova M I , Panayotov V T
Published: March 2021

Trichoderma reesei is a non-pathogenic microorganism able to reduce the toxic for the microorganism silver ions (Ag+) to non-toxic silver nanoparticles (AgNPs). The effect of components of the nutrient medium on which the biomass from T. reesei was obtained on the biosynthesis of AgNPs from Ag+ was monitored. Five media were studied. The main medium (1) contained glucose-2%, NH4Cl-0.1%, CO(NH2)2-0.3%, (NH4)2SO4-0.1%, KH2PO4-0.2%, (NH4)2SO4-0.14%, MgSO4.7H2O-0.03%, CaCl2.2H2O-0.04%. The other were medium 1+0.1% yeast extract (2), medium 1+0.1% corn steep liquor (3), medium 1+0.1% peptone (4), medium 1+0.1% casamino acids (5). After culturing the strain, the resulting biomass was subjected to aqueous extraction, and the cell-free extract - CFE (containing biologically active metabolites) was used for extracellular biotransformation (performed with 10% extracted biomass and 10 mM AgNO3) of Ag+ to AgNPs. The AgNPs formation was monitored by UV-Vis. The isolated nanoparticles were characterized by TEM, ICP-AES and FTIR-ATR. The slowest reduction rate of Ag+ was obtained with the CFE from biomass grown in medium 1 and the highest - with CFE from biomass grown in medium 3. Nearly mono disperse spherical AgNPs (2-6 nm) were synthesized with the aid of CFE of fungi cultivated in media 1 and 3. The AgNPs obtained with CFE from the other media were 4-11 nm.
Electrically tunable reflector based on ferroelectric material for millimetre wavelength range
Authors: Altynnikov A G , Platonov R A , Sosunov A M , Ivanov A D , Legkova T K
Published: March 2021

The design of a millimeter-wave reflector based on the ferroelectric ceramic was elaborated and considered. Among the advantages of the proposed design are simplicity and cost-effectiveness compared to devices based on active repeaters and reflectarrays. The use of ferroelectric ceramic in the reflector design allows operating in a wide frequency range up to 100 GHz. Parameters of ferroelectric ceramic were experimentally measured and used in the electromagnetic simulation of the proposed reflector. Simulation of the reflector’s radiation pattern demonstrated the effective beam scan possibility in a range of 35 deg.
Sustainability and life cycle cost analysis of biomass pyrolysis
Authors: Pang Yoong Xin , Sharmin Nusrat , Lester Edward , Wu Tao , Pang Cheng Heng
Published: March 2021

Pyrolysis is one of the commonly used methods to derive renewable bio-fuels from biomass. A life cycle analysis was performed to evaluate the sustainability and feasibility of such process by utilising simulation results from SuperPro Designer. The process boundary includes biomass pretreatment, main reaction and product collection regimes. Sensitivity analysis was conducted to investigate the influence of cellulose, hemicellulose and lignin on the aspects of economic and environmental impact throughout the life cycle of biomass pyrolysis.
The Effect of Modified LTO Synthesis using Salt Assisted Method with Various of Salt Metal Materials
Authors: Muzayanha Soraya Ulfa , Purwanto Agus , Putra Muhamad Iqbal , Aliwarga Harry Kusuma
Published: March 2021

This study aims to determine the effect of modified LTO synthesis using salt assisted method with various related materials. Salt assisted Li4Ti5O12 for lithium-ion batteries with stable rate-capacity were prepared by simple solid state-mixing, followed by high temperature calcination. This process effected the performance of Li-ion kinetics and stability. Therefore, the salt assisted LTO, which was doped with 1wt% CaCl2, MgCl2, and NaCl presented various discharge capacity, and the highest was shown by LTO-Ca (82.41 mAh g−1, at 0.1C). While the stable rate-capability at 0.5C and 1C were 59.28 mAh g−1 and 58.72 mAh g−1, respectively.
Transparent for microwave electrodes for applications in nonlinear devices based on ferroelectric ceramic
Authors: Alltynnikov A G , Platonov R A , Komlev A E , Tumarkin A V , Sosunov A M , Trofimov P.M. , Tcymbaliuk A A
Published: March 2021

This article provides the results of an experimental investigation of characteristics of thin-films transparent electrodes deposited on ferroelectric ceramic plates. The experimental investigation of parameters of ZnO and resistive alloy of Si-Ti-Ce deposited on ferroelectric BSTO plates was performed. The influence of transparent electrode deposition on properties of ferroelectric ceramic based on a solid solution of barium-strontium titanate was investigated. The measured low insertion loss of the Si-Ti-Ce thin-film deposited on BSTO ceramic substrate allows considering this material as the perspective for the transparent for microwaves electrodes realization.
Genetic Algorithm and Particle Swarm Optimization for Parameter Optimization of Least-Square Support Vector Regression Model in Electricity Load Demand Forecasting
Authors: Irhamah  , Gusti K H , Kuswanto H , Firdausanti N. A.
Published: March 2021

Accuracy is very important in time series forecasting where the model obtained depends on historical, linear, or nonlinear data patterns. This study aims to forecast short term electricity load in East Java, Indonesia, whereas electricity load is one of major and vital need in our daily life. The linear approach is carried out using the ARIMA method, while the nonlinear approach used in this study consist of the SVR and LSSVR models. The parameter selection greatly affects the results of accuracy, so an optimization method is needed. The usual grid search optimization method does not guarantee an optimum solution and more importantly, it is not efficient in some practical applications. Therefore metaheuristic optimization methods are needed, including GA and PSO which can find the entire possible space for the search for solutions. PSO is easier to apply but is prone to have premature convergence due to trapped in the minimum locale. To overcome this, modified PSO is developed to seek the optimal position according to the specified criteria. The result of this research is that the accuracy of the nonlinear approach is much better than the linear approach. The addition of an optimization method to the SVR provides a significant change in accuracy compared to LSSVR. Meanwhile, MPSO is the best optimization method because it produces a lowest RMSE value.
A Study on the Release of Nanoparticles to the Environment from Nano-Enabled Asphalt by Weathering Experiment
Authors: Llana M J , Tolentino M S , Valeza N C C , Reyes J P , Basilia B A
Published: March 2021

Researches in the field of nanotechnology is continuously gaining a lot of interest due to its wide range of applications. This study focused on the incorporation of halloysite nanotubes (HNT’s) on asphalt and on the investigation of the release of the said nanoparticles from the asphalt to the environment through accelerated weathering experiment. Two (2) samples were prepared: asphalt with HNT (A1) and asphalt only (A2). SEM-EDX results showed that A1 initially had nanoparticles on the surface which can be attributed to the added HNT. SEM images further showed the changes on the surface morphologies of A1 and A2 after accelerated weathering experiment. These changes can be further correlated to the intercalation and exfoliation reactions that happened on the surface of asphalt during UV irradiation. Release studies revealed that Al and Si nanoparticles were being released on the surface due to the layer by layer degradation of the asphalt matrix. Hence, continuous exposure of asphalt could result to further degradation of asphalt, leading to the surfacing and release of more nanoparticles.
Experimental analysis of the performance characteristics of the regenerative fuel cell system based on serpentine flow-field design
Authors: Ho Nang Xuan , Nguyen Duy Vinh
Published: March 2021

The energy demand has recently been increasing dramatically; thus, it is evident that scientists worldwide need to find out the solution to solve the above problem. Among these technologies, solar and wind power energy are the most potential source as alternatives to fossil fuels. However, these energy sources are not continuous and are therefore considered as additional sources. A regenerative fuel cell (RFC) is a type of fuel cell that can function as an electrolyzer and fuel cell; therefore, this system is an independent power source and overcome the drawbacks of the original fuel cell system. This research has built a system to control the entire regenerative fuel cell system’s flow, temperature, and energy. The system uses electricity to produce hydrogen and oxygen for storage; when the electrical power is insufficient, the system can automatically reverse the operation using hydrogen and oxygen to create electrical energy. The result showed that the power density in fuel cell mode ranges from 0.1 to 0.69W/cm2in the fuel cell mode, and the flow rate of hydrogen and oxygen reaches a stable value of 1100 and 2200 ml/min after 10 minutes, respectively.
Simulation of surface work-hardening process during controlled inertial impact treatment of parts made of high strength cast iron
Authors: Pashkevich V M , Afanevich V V
Published: March 2021

The paper deals with the results of simulation of elastoplastic impact of the deforming ball with the surface during inertial impact treatment. The deforming ball is made of hardened steel ShKh15 (GOST 801-78), and special high strength spheroidal graphite cast iron is used as the treated material. The paper provides recommendations on conditions for inertial impact treatment of surfaces.
Thermal conductivity and heat capacity of nanofluid based on water modified by hybrid material of composition detonation nanodiamonds-carbon nanotubes
Authors: Vozniakovskii A A , Voznyakovskii A P , Kidalov S V , Kalashnikova E K
Published: March 2021

This paper is devoted to assessing the prospects of using a DND-CNT hybrid material to improve water’s thermophysical properties compared with pure DND and CNT. A hybrid powdered nanomaterial composed of detonation nanodiamonds-multi-walled carbon nanotubes was synthesized by growing multi-walled carbon nanotubes on the surface of nanodiamonds aggregates coated with catalyst using CCVD method for nanotubes growth. The mass fraction of CNTs in the hybrid material was 30%. Using 0.2 mass. % of the hybrid material, we managed to increase the thermal conductivity of water by 94% and increase the specific heat by 17% (at a temperature of 60 degrees) without changing the kinetic viscosity of water. Using initial detonation nanodiamonds or commercial single-walled nanotubes as an additive at the same concentration and temperature, the maximum increase in thermal conductivity was only 37%, and the maximum increase in specific heat was only 5%. Simultaneously, the mechanical mixture of detonation nanodiamonds and carbon nanotubes (in a 7 to 3 ratio) did not form stable water suspensions.
Failures of safety services in case of emergency fall of cargo-passenger elevator’s cabin exploited in industrial and civil premises
Authors: Popov M , Negodin A
Published: March 2021

The growing fleet of elevators and other short distance vehicles (escalators, passenger conveyors and multi-cabin elevators) require constant improvement of installation methods and technical servicing to increase reliability and safety levels when used. When elevators are used for transporting people, the issue of reliability is becoming very important. The realibility indicator is not a constant value, since it has a direct dependence on a time factor, the main component of which is the standard service life of the main units and kinematic constrains of the equipment used for elevators. As a result, over time, the risk of accidents and emergencies in residential buildings may increase.
Simulation on elevator emergency brake
Authors: Popov M , Negodin A
Published: March 2021

Modern calculation methods used for hoisting units are reduced to obtaining the value of the required braking force when the values of mass and speed have been captured. Copies of the oscillograms with kinematic parameters on braking of passenger elevator cabins show that the acceleration tendencies when landing on soft braking devices are not linear. Consequently, the cabin braking forces also do not change linearly and are not constant since the moment after braking has started to the moment when it stops. The calculation methods give only the maximum value of the required braking force and the length of the cabin braking distance. The elevator cabin braking (counterweight) with safety devices takes some time. During this time, the braking force changes from zero to the maximum value, which, at high speeds of the cabin (counterweight) affects the acceleration of slow-down process, and the brake-path length. When simulating the braking force of elevator catchers, it is necessary to take into account the change of the braking force value.
The Study of the Power Supply System of the Existing Gas Fields in Western Siberia using the Theory of Experimental Planning
Authors: Bogachkov I M
Published: March 2021

Nowadays most of the gas fields in Western Siberia are at the final stage of development. To extend the cost-effective gas production at the final stage of development modern technologies are introduced at the fields. One of these technologies is the technology of distributed gas compression. As a result, a multiple increase in the electrical load is observed and new power transmission lines and substations are being constructed to provide electricity to gas fields. For example, at Vyngapurovsky gas field MCU (9 PCs) were to be put into operation and the 6 kV OHL with a length of 22 km were needed to be built, at Yamburg gas field at the moment MCU (52 PCs) are to be set up and it is required to build the 10 kV OHL with a length of 480 km. Thus, the purpose of this paper is to conduct an experimental study of the existing supply and distribution grids of the gas fields’ power supply system in Western Siberia. To achieve this goal the following tasks have been solved: the method of the mathematical models development was selected; the main influencing factors on the voltage class were identified; variation ranges of the selected factors were defined; the optimization of the power supply schematic diagrams for the choice of voltage with minimal discounted costs was completed by the computer program PRON. The problems have been solved using the empirical method (measurement, comparison) of the study, the method of experiment planning (full factorial experiment), and computer programming methods. The analysis shows that all distribution grids of the power supply system in Western Siberia need to be converted to a higher voltage class of 20 kV or the additional overhead lines should be built.
Developing a nanostructured surface layer on AISI 316 stainless steel by ultrasonic surface nanocrystallization and evaluating its tribological properties
Authors: Ballam Masoud Hosseini , Karimzadeh Fathallah , Enayati Mohammad Hossein , Sanati Alireza
Published: March 2021

Austenitic stainless steels have received a lot of attention for a wide range of applications, including petrochemical, automotive industry, building architecture, and bioengineering; however, their poor mechanical properties such as high wear rate are always challenging. In this research, ultrasonic surface nanocrystallization treatment (USNT) has been used for surface modification and improvement of tribological characteristics of AISI 316 stainless steel. For this purpose, 375 N accompanied with 20 kHz vibration frequency was applied on the surface to provide static and dynamic forces simultaneously, increase dislocations density, and fabricate a nanocrystalline surface. After this process, the untreated and USN-treated specimens were characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy, x-ray diffraction analysis, Vickers microhardness measurements, and surface profilometry. Also, a reciprocating pin-on-plate test was used to evaluate the tribological features of the surface. After the wear test, the untreated sample showed approximately twice weight loss, in comparison with the USN-treated specimen. The friction coefficient during 500 m sliding was reduced from around 1 (for the untreated specimen) to 0.4 after USNT. Also, the SEM investigations showed that the abrasive wear is decreased after USNT. The improved tribological properties of AISI 316 in this research was attributed to the residual compressive stress, nanocrystallization, strain-induced phase transformation, microhardness enhancement, and surface roughness reduction after USNT.
Investigation of magnesium addition in ZnO matrix using group II heptahydrate
Authors: Hussain Hadba , Albrithen Hamad A , Alshammari Abeer , Alyamani Ahmed , Bano Nargis , Alyemni Sarah Nasser , AlAhmary Shareefah Ayed , Alanzi Ali , Almutairy Baderah Awad
Published: March 2021

ZnO and MgZnO nanoparticles were prepared by the co-precipitation method utilizing zinc sulfate heptahydrate and magnesium sulfate heptahydrate; structural measurements were also carried out. An x-ray diffraction (XRD) study indicated that no peaks for other possible phases such as MgO or MgZn intermetallic compounds indicating pure wurtzite structure. All nanoparticles crystallized in a hexagonal wurtzite structure with different orientation diffraction peaks; the main peaks were (100), (002), and (101). Grain size (D) increased with increasing Mg concentrations. A scanning electron microscopy (SEM) analysis revealed that nanoparticle size increased by increasing the Mg concentration in a good qualitative with Scherrer equation and not only the size even the grain shape changed. In addition, optical measurements were taken infer that the band gap energy (Eg), extracted from Tauc’s plot, decreases with increasing of the Mg concentration doped, and found to be between 3.255 eV and 3.169 eV. The photoluminescence (PL) emission spectra show two peaks at the ultraviolet and green regions.
Effect of (Ti, Nb)(C, N) solid-solution powder on microstructure and mechanical properties of Ti(C, N)-based cermets: key experiment aided by thermodynamic calculations
Authors: Lv Jian , Zhang Cong , Zhang Weibin , Long Jianzhan , Yue Yang , Zheng Zhenghui , Du Yong
Published: March 2021

The preparation of Ti(C, N)-based cermets using (Ti, Me)(C, N) solid-solution powder instead of the traditional Ti(C, N) + MeC mixtures has gradually become a popular research subject. By using a (Ti, Nb)(C, N) solid-solution powder and Ti(C, N) + NbC powder, the microstructures and mechanical properties of Ti(C, N)-based cermets were investigated in the present work with the guidance of thermodynamic calculations. The thermodynamic calculations indicated that the (Ti, Nb)(C, N) was thermodynamically less stable than the Ti(C, N), which led to a difference in the microstructures and properties of the cermets prepared using (Ti, Nb)(C, N) and Ti(C, N) + NbC. The cermet prepared using the (Ti, Nb)(C, N) solid-solution powder had a no/weak core–rim structure. Moreover, the surface binder-rich phases of the cermets prepared by the (Ti, Nb)(C, N) solid solution was thinner under vacuum sintering, which was beneficial for improving the surface quality of the cermets. The hardness values of the cermets prepared using (Ti, Nb)(C, N) were greater than those of the cermets prepared using Ti(C, N) + NbC, and the fracture toughness underwent no noticeable change.
Controllable preparation of trifold nanorods and nanospheres of cadmium telluride via solvothermal process
Authors: Kang Weifeng , Li Shuo , Wang Cong , Zhang Linhui , Zhong Binnian
Published: March 2021

In this study, trifold CdTe nanorods and CdTe nanospheres were prepared by the environmentally benign solvothermal process where K2TeO3 and CdCl2 acting as the raw materials, L-ascorbic acid as the reducing agent, ethylene glycol as the solvent and polyvinylpyrrolidone as the surfactant, respectively. The morphology of the products can be regulated by the amount of KOH. Specifically, trifold CdTe nanorods could be prepared with 0.1 g of KOH before the reaction; while CdTe nanospheres were obtained with 0.5 g of KOH. The higher the amount of KOH added, the stronger the reducibility of L-ascorbic acid. For higher reducibility, CdTe crystal nuclei which was continuously generated will first nucleate and grow in the gaps between the rods of the trifold nanorods because of the special morphology and structure of the trifold nanorods. Therefore, with the increasing of the number of CdTe crystal nuclei caused by the accelerated reaction rate, the trifold nanorods will gradually evolve into nanospheres.
Extracting electron scattering cross sections from swarm data using deep neural networks
Authors: Jetly Vishrut , Chaudhury Bhaskar
Published: March 2021

Electron-neutral scattering cross sections are fundamental quantities in simulations of low temperature plasmas used for many technological applications today. From these microscopic cross sections, several macro-scale quantities (called ‘swarm’ parameters) can be calculated. However, measurements as well as theoretical calculations of cross sections are challenging. Since the 1960s, researchers have attempted to solve the inverse swarm problem of obtaining cross sections from swarm data; but the solutions are not necessarily unique. To address these issues, we examine the use of deep learning models which are trained using the previous determinations of elastic momentum transfer, ionization and excitation cross sections for different gases available on the LXCat website and their corresponding swarm parameters calculated using the BOLSIG+ solver for the numerical solution of the Boltzmann equation for electrons in weakly ionized gases. We implement artificial neural network (ANN), convolutional neural network (CNN) and densely connected convolutional network (DenseNet) for this investigation. To the best of our knowledge, there is no study exploring the use of CNN and DenseNet for the inverse swarm problem. We test the validity of predictions by all these trained networks for a broad range of gas species and we deduce that DenseNet effectively extracts both long and short term features from the swarm data and hence, it predicts cross sections with significantly higher accuracy compared to ANN. Further, we apply Monte Carlo dropout as Bayesian approximation to estimate the probability distribution of the cross sections to determine all plausible solutions of this inverse problem.
Sharp error estimates of a spectral Galerkin method for a diffusion-reaction equation with integral fractional Laplacian on a disk
Authors: Hao Zhaopeng , Li Huiyuan , Zhang Zhimin , Zhang Zhongqiang
Published: March 2021

We investigate a spectral Galerkin method for the two-dimensional fractional diffusion-reaction equations on a disk. We first prove regularity estimates of solutions in the weighted Sobolev space. Then we obtain optimal convergence orders of a spectral Galerkin method for the fractional diffusion-reaction equations in the

L
2

L^2

and energy norm. We present numerical results to verify the theoretical analysis.
Global gradient estimates for a general class of quasilinear elliptic equations with Orlicz growth
Authors: Baasandorj Sumiya , Byun Sun-Sig , Lee Ho-Sik
Published: March 2021

We provide an optimal global Calderón-Zygmund theory for quasilinear elliptic equations of a very general form with Orlicz growth on bounded nonsmooth domains under minimal regularity assumptions of the nonlinearity

A
=
A
(
x
,
u
,
D
u
)

A=A(x,u,Du)

in the first and second variables

(
x
,
z
)

(x,z)

as well as on the boundary of the domain. Our result improves known regularity results in the literature regarding nonlinear elliptic operators depending on a given bounded weak solution.
Evaluating the Mahler measure of linear forms via the Kronecker limit formula on complex projective space
Authors: Cogdell James , Jorgenson Jay , Smajlović Lejla
Published: March 2021

In Cogdell et al., LMS Lecture Notes Series 459, 393–427 (2020), the authors proved an analogue of Kronecker’s limit formula associated to any divisor

D

\mathcal D

which is smooth in codimension one on any smooth Kähler manifold

X
X

. In the present article, we apply the aforementioned Kronecker limit formula in the case when

X
X

is complex projective space

C

P

n

\mathbb {C}\mathbb {P}^n

for

n
≥
2

n \geq 2

and

D

\mathcal D

is a hyperplane, meaning the divisor of a linear form

P
D

(

z

)

P_D({z})

for

z

=
(

Z

j

)
∈

C

P

n

{z} = (\mathcal {Z}_{j}) \in \mathbb {C}\mathbb {P}^n

. Our main result is an explicit evaluation of the Mahler measure of

P

D

P_{D}

as a convergent series whose each term is given in terms of rational numbers, multinomial coefficients, and the

L

2

L^{2}

-norm of the vector of coefficients of

P

D

P_{D}

.
Enunciation
Authors: Smith Russell
Published: March 2021

Enunciation refers to the act of making a spoken or written statement, as opposed to the content of the statement. It is associated with the work of French linguist Émile Benveniste, whose Problems in General Linguistics (1966) argued that formalist and structuralist accounts of language fail to pay sufficient attention to the fact that many of the core elements of any language, such as the pronouns “I” and “you,” are entirely dependent for their function on the unique circumstances in which they are enunciated. Enunciation thus describes the process by which a speaker or writer takes up the position of a linguistic subject. Benveniste further argued that all acts of language use are fundamentally dialogical in nature, although the individual acts of speaking and listening, writing and reading may be widely separated in place and time. These questions played a pivotal role in the shift, both in literary theory and in the human sciences more broadly, from structuralism to poststructuralism through the course of the late 1960s and early 1970s. This involved a shift from the study of language as a signifying system, to the study of discourse as the range of different processes by which individual acts of speaking and writing, listening and reading, are framed in advance by formal and informal rules and conventions. Every actual instance of language use is inseparable from its enunciative situation, and this entails attention to the questions of who is speaking, to whom, and why? As developed in different ways by theorists such as Julia Kristeva and Jacques Lacan, Roland Barthes and Michel Foucault, the linguistics of enunciation would raise profound questions about the role of language in the formation of subjectivity and in the discursive operation of power.
Inferential Statistics
Authors: Wilcox Rand R.
Published: March 2021

Inferential statistical methods stem from the distinction between a sample and a population. A sample refers to the data at hand. For example, 100 adults may be asked which of two olive oils they prefer. Imagine that 60 say brand A. But of interest is the proportion of all adults who would prefer brand A if they could be asked. To what extent does 60% reflect the true proportion of adults who prefer brand A?

There are several components to inferential methods. They include assumptions about how to model the probabilities of all possible outcomes. Another is how to model outcomes of interest. Imagine, for example, that there is interest in understanding the overall satisfaction with a particular automobile given an individual’s age. One strategy is to assume that the typical response Y, given an individuals age, X, is given by Y=β0+β1X, where the slope, β1, and intercept, β0, are unknown constants, in which case a sample would be used to make inferences about their values. Assumptions are also made about how the data were obtained. Was this done in a manner for which random sampling can be assumed? There is even an issue related to the very notion of what is meant by probability. Let μ denote the population mean of Y. The frequentist approach views probabilities in terms of relative frequencies and μ is viewed as a fixed, unknown constant. In contrast, the Bayesian approach views μ as having some distribution that is specified by the investigator. For example, it may be assumed that μ has a normal distribution. The point is that the probabilities associated with μ are not based on the notion of relative frequencies and they are not based on the data at hand. Rather, the probabilities associated with μ stem from judgments made by the investigator.

Inferential methods can be classified into three types: distribution free, parametric, and non-parametric. The meaning of the term “non-parametric” depends on the situation as will be explained. The choice between parametric and non-parametric methods can be crucial for reasons that will be outlined. To complicate matters, the number of inferential methods has grown tremendously during the last 50 years. Even for goals that may seem relatively simple, such as comparing two independent groups of individuals, there are numerous methods that may be used. Expert guidance can be crucial in terms of understanding what inferences are reasonable in a given situation.
Entrepreneurial Resilience
Authors: Garrett Robert , Zettel Lauren
Published: March 2021

Given that entrepreneurs regularly face challenges in the process of starting a new venture, their ability to adapt and respond to adversity is of great interest to entrepreneurship researchers. Hence, entrepreneurship scholars have begun to build on and extend the idea of individual-level, psychological resilience in the domain of entrepreneurship. Entrepreneurial resilience includes the processes entrepreneurs utilize to develop and deploy their capabilities in order to adapt and respond to adversity encountered in their role as an entrepreneur. Entrepreneurial resilience may be conceptualized as a set of capabilities, as a process, and as an outcome. The idea of entrepreneurial resilience as a set of capabilities implies that resilience is comprised of certain psychological and behavioral capacities or tendencies that allow an entrepreneur to overcome adversity. Entrepreneurial resilience as a process is the demonstration of those capabilities in action and is exhibited as entrepreneurs encounter and then recover from a stressor. Finally, entrepreneurial resilience as an outcome is often conceptualized as a lack of negative outcomes from an adverse or stressful event.

Research in entrepreneurship has begun to explore each of these conceptualizations of resilience. Importantly, resilience capabilities have been connected with a greater likelihood of venture survival. Additionally, research has demonstrated that entrepreneurial action may be an important tool that individuals use to overcome persistent adversity. Future research is needed to clarify how entrepreneurs both develop and deploy their capabilities and resources to achieve positive outcomes in the face of challenges. The remaining questions related to the nature of entrepreneurial resilience make this domain a promising field for continuing scholarship.
Crisis Mapping and Crowdsourcing in Complex Emergencies
Authors: Ziemke Jen , Jayamaha Buddhika , Jahn Molly M.
Published: March 2021

Crisis mappers secure satellite imagery, photos, video, event data, incident data, and other documentary evidence to create an operational picture of a disaster in order to facilitate improved humanitarian response and assistance in a crisis.

The era of human-powered crisis mapping between 2009 and 2014 was a bootstrapped effort very much a function of the peculiar state of technological development at the time—available but not yet formalized, streamlined, and automated. Humans filled the gap until machine assistance could catch up. These efforts, often mundane (e.g., cut and paste over and over for hours), were more reflective of the state of technology at the time than anything else.

Another precondition that enabled the field to grow is the often taken-for-granted public good provided by the GPS satellites maintained by the U.S. Air Force. Without this service, the project at the time would not have emerged where and when it did.

The future will be shaped as a result of improvements in automated forms of data collection; improved machine learning techniques to help filter, identify, visualize, and analyze the data; and the proliferation of low-cost drones and other forms of sensors, to name a few.
Military and Absentee Voting in the United States: History and Modern Practice
Authors: Inbody Donald S.
Published: March 2021

The advent of absentee voting for American citizens began with the desire on the part of soldiers to participate in the electoral process. It was aided by politicians who wanted the support of those soldiers. The rise of absentee voting was later extended to nonmilitary Americans living overseas or otherwise away from their home precincts. Resistance to absentee voting was strong at first, largely on philosophical grounds (i.e., the question of why someone away from home would be interested in voting, or absentee voting inviting vote fraud). It was also resisted by political parties who were convinced that those voters may vote for the opposition candidate.

Gradually, in the post-World War II years, nearly all resistance faded but never disappeared. Vestigial perceptions of the voting habits of military personnel remained as late as the first years of the 21st century. Congress was convinced to pass several voting rights laws that eventually extended the right to vote to all Americans serving in the military or living overseas, although some barriers remain to be overcome.
Afghanistan: Martial Society Without Military Rule
Authors: Tarzi Amin
Published: March 2021

Since its inception as a separate political entity in 1747, Afghanistan has been embroiled in almost perpetual warfare but has never been ruled directly by the military. From initial expansionist military campaigns to involvement in defensive, civil, and internal consolidation campaigns, the Afghan military until the mid-19th century remained mainly a combination of tribal forces and smaller organized units. The central government, however, was only able to gain tenuous monopoly over the use of violence throughout the country by the end the 19th century. The military as well as the Afghan society remained largely illiterate and generally isolated from the prevailing global political and ideological trends until the middle of the 20th century.

The politicization of the Afghan military began in very small numbers after World War II, with Soviet-inspired communism gaining the largest foothold. Officers associated with the People’s Democratic Party of Afghanistan were instrumental in two successful coups d’état in the country. In 1979, the Soviet Union invaded Afghanistan, ending the country’s sovereignty and ushering in a period of conflict that has continued into the third decade of the 21st century in varying degrees. In 2001, the United States led an international invasion of the country, which was followed by efforts to organize smaller, professional Afghan national defense forces, which remained largely apolitical and became the country’s most effective and trusted governmental institution. However, designed by foreign forces to support foreign goals, they disintegrated when left to defend the country independently against the Taliban in 2021. The Taliban may represent a new phenomenon in Afghanistan, that of having a politicized militarized force.
The Genetic Epistemology of Jean Piaget
Authors: Burman Jeremy Trevelyan
Published: March 2021

Jean Piaget (1896–1980) is known for his contributions to developmental psychology and educational theory. His name is associated especially with Stage Theory. That we believe him to have focused solely on cognitive development, however, is not because he did. This is instead the result of the popularization of his writings in the United States during the Cold War. (A period of crisis and subsequent education reform.) The overpowering influence of those interests blinded us to his larger framework, which he called “genetic epistemology,” and of which his stages were just a part. To address the resulting and continuing misunderstandings, this essay presents original historical scholarship—distilling over a thousand pages of archival documents (correspondence, diary entries, budgets, and reports)—to provide an insider’s look at Piaget’s research program from the perspective of the Rockefeller Foundation: genetic epistemology’s primary funding agency in the United States from the mid-1950s through the early-1960s. The result is an examination of how a group of interested Americans came to understand Piaget’s writings in French in the period just prior to their wider popularization in English, as well as of how Piaget presented himself and his ideas during the reconstruction of Europe after World War II. My goal, however, is not to summarize the whole of this misunderstood program. Instead, I aim to provide a source of archivally-grounded perspective that will allow for new insights about the Genevan School that are unrelated to American Cold War interests. In the process, we also derive new means to see how Piaget’s experimental examinations of the development of individual knowledge served to inform his team’s investigations of the evolution of science (and vice versa).
Curriculum of Migrant Communities in Mainland China
Authors: Yu Min
Published: March 2021

The establishment of the community schools for migrant children and the development of curriculum for migrant children in China’s migrant communities speak to the critical questions concerning whose knowledge counts and what is worthwhile for children from underserved communities. The spaces provided by the migrant children schools encouraged the formation of a sense of solidarity among migrant students, their families, and teachers, as well as active members outside the communities. The sense of solidarity was reflected by the blurred boundary between schools and familial spaces. Located inside migrant communities, migrant children schools contributed to the formation of a sense of collectivity among the students, their teachers, their families, and other members of the migrant communities. Many of the schools, regardless of size, number of teachers, with permits or without official recognition, organized various activities and opportunities to bring personal, family, and community experiences into school curriculum and extracurricular activities, or to encourage everyone to join community events.

The collective understanding of living and working in the migrant communities was formed among teachers and parents, especially when they shared both roles in a community. Although excluded from the public realm for decades, migrant communities never stopped their mobilization towards providing education for their children and making their voices heard. In the spaces provided by migrant children schools, students and teachers used a variety of ways to tell their own stories. The vitalizing activities in the communities not only challenged the stereotypes of migrant children and their schools but also provided opportunities to mobilize people outside the communities and beyond the basic communal networks to further collaborate with and to support the work of migrant children’s schooling.
Oral History Illustrated by the Case of Cyprus
Authors: Christodoulou Nicoletta (Niki) , Christou Miranda , Hadjipavlou Maria
Published: March 2021

Oral history offers unique meaning for curriculum studies by presenting, analyzing, and interpreting experiences and memories of participants in an educational situation. The situation and context of Cyprus, an island with protracted conflicts and ethnical division, provides sites of illustration for oral history in curriculum studies. Couched in an historical background of oral history and definitions, as well as characteristics that distinguish it from other forms of narrative inquiry, the essence and application of oral history can be conveyed through the case of Cyprus. Oral history projects undertaken in Cyprus are conveyed, with prominent reference to the Cyprus Oral History Project (COHP), which has delineated the nuances of language, performance, and creation of pedagogical spaces. For example, COHP established a link among oral history, curriculum, instruction, and education, which has been used in Cyprus to understand memory as curriculum and to rethink issues of language and curricular questions in light of the knowledge drawn from oral histories. Further, oral history projects in Cyprus have delineated refugee trauma through the description of loss, painful memories, and silence; how narratives worked as significant evidence and material in conflict and reconciliation workshops; and the importance of the gender lens of oral history in Cyprus. The themes of cultivating historical consciousness, shaping responses to conflict, discomforting pedagogy, memory and trauma, and their role in the reunification process have been explored extensively through such projects; yet, more extensive work needs to be done. The number of oral history projects is still limited, yet there is still so much to be uncovered through people’s narrations. In the case of Cyprus, oral history is considered as a source of information about ordinary people’s lives but also for the role it can play in understanding how being dispossessed and returning to the homeland can reconstruct and reorganize education and culture. The uses of oral history to understand curriculum in Cyprus is offered as an example for modified use for exploring a broader sphere of curriculum studies in other settings.