Miracle-dz/UniFAR-FTUs huggingface dataset:
Mathematical Modeling of Rechargeable Hybrid Aqueous Batteries

A rechargeable hybrid aqueous battery (ReHAB) system was recently developed by our research group. It has been improved via different experimental approaches, but nobody yet has tried to use mathematical modeling techniques to further understand the system. This thesis tries to investigate the ReHAB system using a few current modeling methods. The study is categorized into empirical level, electrochemical engineering level and atomistic level. At the empirical level, a battery is simply viewed as a whole system, which means detailed descriptions in terms of the cathode, anode or electrolyte are ignored. By using the historical experimental data, researchers can predict the future behavior of a battery regardless of its internal phenomena. They usually employ some general mathematical functions, such as polynomial, logarithmic, exponential or other nonlinear functions. Currently automatic curve fitting and predicting algorithms are commonly used in the battery management system, due to the advantage in coping with the system nonlinearity. The first study in this thesis implements a tracking method called particle filter method on the ReHAB experimental data. The basic math function in the simulation is an empirical formula between the battery capacity and the Coulombic efficiency. The study confirms this correlation in the ReHABs, and proves that particle filter method can be a good option in battery performance tracking and prediction. At the electrochemical engineering level, battery performance is simulated in the continuum models, by incorporating chemical or electrochemical reactions, transport phenomena or interfacial kinetics. This level of simulation can help observe battery electrodes in details. It is more accurate than the empirical level model, and more versatile in simulating various electrochemical problems. This thesis secondly focuses on the ReHAB system cathode and anode using finite element method, which is implemented in COMSOL Multiphysics. The study includes a design of battery system model, investigation of species distribution during cell operation, side-reaction effects and anode corrosion issues. The models designed at this level give consistent results compared with the experimental data, and illustrate some guidance for the potential experiments. At the atomistic level, molecular simulation can model the system dynamics via step-
Computational Design of Planar Multistable Compliant Structures

This article presents a method for designing planar multistable compliant structures. Given a sequence of desired stable states and the corresponding poses of the structure, we identify the topology and geometric realization of a mechanism—consisting of bars and joints—that is able to physically reproduce the desired multistable behavior. In order to solve this problem efficiently, we build on insights from minimally rigid graph theory to identify simple but effective topologies for the mechanism. We then optimize its geometric parameters, such as joint positions and bar lengths, to obtain correct transitions between the given poses. Simultaneously, we ensure adequate stability of each pose based on an effective approximate error metric related to the elastic energy Hessian of the bars in the mechanism. As demonstrated by our results, we obtain functional multistable mechanisms of manageable complexity that can be fabricated using 3D printing. Further, we evaluated the effectiveness of our method on a large number of examples in the simulation and fabricated several physical prototypes.
THE VALIDITY OF REAL-TIME DATA GENERATED BY A WEARABLE

The purpose of this study was to investigate the validity of global positioning system (GPS) and micro-electrical-mechanical-system (MEMS) data generated in real-time via a dedicated receiver. Post-session data acted as criterion as it is used to plan the volume and intensity of future training and is downloaded directly from the device. 25 professional rugby league players completed two training sessions wearing a MEMS device (Catapult S5, firmware version: 2.27). During sessions, real-time data was collected via the manufacturer receiver and dedicated software (Openfield v1.14) which was positioned outdoors at the same location for every session. GPS variables included total-, low(0 to 3 m∙s), moderate(3.1 to 5 m∙s ), high(5.1 to 7 m∙s) and very-high-speed (> 7.1 m∙s) distances. MEMS data included total session PlayerLoadTM. When compared to post-session data, mean bias for total-, low-, moderate-, highand very-high-speed distances were all trivial, with the typical error of the estimate (TEE) small, small, trivial, trivial and small respectively. Pearson correlation coefficients for total-, low-, moderate-, highand very-high-speed distances were nearly perfect, nearly perfect, perfect, perfect and nearly perfect respectively. For PlayerLoadTM, mean bias was trivial whilst TEE was moderate and correlation nearly perfect. Practitioners should be confident that when interpreting real-time speed-derived metrics, the data generated in real-time is comparable to that downloaded directly from the device postsession. However, practitioners should refrain from interpreting accelerometer derived data (i.e. PlayerLoadTM) or acknowledge the moderate error associated with this real-time measure.
Designing a low cost passively Q-switched solid state laser transmitter

A discrete Q-switched laser that gives a side-lobed single pulse as a laser output was implemented; followed by studying energy extraction efficiencies and pulse characterisation. The aim was to help design a passively Q-switched laser that gives a smooth single pulse of optimum energy as a laser output. The smoothness feature in a single pulse is important in some applications such as range finding. The concepts are demonstrated both experimentally and numerically; the latter using Fox-Li approach to modeling resonator modes with the Fresnel’s integral for the system under study. In the first two chapters, fundamentals of how a laser works and the spatial mode development are studied. In chapter 1, the principles of a laser are discussed: absorption, spontaneous and stimulated emission. Also, different types of pumping sources and resonator configurations that can be used are discussed. In chapter 2, the focus is on developing spatial modes of a laser. The fundamental and high order modes are discussed together with their propagation laws. Then a numerical method is used to find the eigenmodes of an arbitrary resonator configuration. This numerical method is used to simulate propagation of a fundamental mode and the simulation results are compared to analytical propagation laws. Then, this numerical method is used to simulate a laser resonator. The eigenmode of the lowest loss in the resonator was found. In chapters 3 and 4, experimental work is done on a Q-switched laser where the focus is on the overall laser performance. In chapter 3, Q-switched laser output energies are studied for different combinations of Q-switch transmission values and output coupler reflectivities. In addition, the influence of spatial modes on a Q-switched pulse shape and pulse width are studied, taking into account beam divergence. In chapter 4, conclusions and future work are presented. In future work, the knowledge of spatial mode influence on pulse shape, pulse width and beam divergence from chapter 3 is exploited. Then particular resonator configuration that gives optimised output results (Q-switched laser output energy, beam divergence, pulse shape and pulse width) is chosen. On that particular resonator, different Q-switch transmission values are studied, but now looking only at beam divergence and pulse width. Also, some suggestions on further improving laser performance are given.
PALEOSTRIPv1.0 – a user-friendly 3D backtracking software to reconstruct paleo-bathymetries

Abstract. We present PALEOSTRIPv1.0, a MATLAB open-source software designed to perform 1D, 2D and 3D backtracking of paleo-bathymetries. PALEOSTRIP comes with a Graphical User Interface (GUI) to facilitate computation of sensitivity tests and to allow the users to switch on and off all the different processes and thus separate the various aspects of backtracking. As such, all physical parameters can be modified from the GUI. It includes 3D flexural isostasy, 1D thermal subsidence and possibilities to correct for prescribed sea level and dynamical topography changes. In the following we detail the physics embedded within PALEOSTRIP and we show a few applications on a drilling site (1D), a transect (2D) and a map (3D), taking the Ross Sea (Antarctica) as a case study. PALEOSTRIP has been designed to be modular and to allow user to insert their own implementations.
Competition and Collaboration in the Nonprofit Sector: Identifying the Potential for Cognitive Dissonance

Nonprofits compete with collaborators and collaborate with competitors regularly. Collaboration, a long-standing normatively preferred strategy for nonprofits, is utilized as modus operandi without thought to the potential unintended consequences. While competition is a dirty word for nonprofits, it is a necessary but undesirable reality and should not be avoided without consideration to the potential benefits. Nonprofit leaders may not be willing to explicitly acknowledge the use of competition as an operational strategy, which makes room for cognitive dissonance to impact the study of nonprofits. This piece identifies impacts of cognitive dissonance offering direction for future research exploring the interactive nature of competing with collaborators.
Highly active Ni-Fe double hydroxides as anode catalysts for electrooxidation of urea

Urea is a safe and sustainable chemical for electrochemical energy conversion and storage. However, the sluggish kinetic rates of the electrooxidation reaction of urea as well as catalyst stability still remain to be challenges. In this work, we investigated several catalysts for the electro-oxidation of urea by directly growing NiM double hydroxides (M = Cr, Mn, Fe, Co, Cu, Zn) on carbon fibre cloth and nickel foam electrodes through a facile one-step hydrothermal synthesis method. The results indicated that the activity was significantly related to the elemental composition. Among the investigated double hydroxides, the NiFe double hydroxide (DH) catalyst showed the highest activity, which achieved a specific current density of ∼95 mA cm−2 mg−1 at 0.5 V vs. Ag/AgCl, about 10 times larger than that of Ni(OH)2. In addition, the NiFe DH also had a high activity when grown on a Ni foam substrate. This NiFe DH performs well in the aspect of urea oxidation stability, demonstrating it to be a promising low-cost and stable catalyst for the efficient electrooxidation of urea under alkaline conditions.
ARMA-GARCH model for value-at-risk (VaR) prediction on stocks of PT. Astra Agro Lestari.Tbk

PT. Astra Agro Lestari Tbk (AALI) is one of the plantation companies with the largest market capitalization in Indonesia. AALI stocks traded on the stock exchange have fairly fluctuating value and volatility of stock returns are not constant (heteroskedastic). One of the risk measurements that can be used to predict the risk of stock investing is Value-at-Risk (VaR). In conditions that are heteroskedastic stock returns, risk prediction can be done with the VaR ARCH/GARCH and VaR ARCH/GARCH combination model. Empirical studies were carried out on AALI stocks for the period of August 2, 2012 until October 1, 2019. The results obtained showed that the best model was ARIMA (0,0,1)-GARCH (1,2) with AIC value of -4.9793 and MSE of 0.00005. At the 95% trust level, the VaR ARCH/ARCH value was -0.3464.
Perception of material appearance: A comparison between painted and rendered images

Abstract Painters are masters in replicating the visual appearance of materials. While the perception of material appearance is not yet fully understood, painters seem to have acquired an implicit understanding of the key visual cues that we need to accurately perceive material properties. In this study, we directly compare the perception of material properties in paintings and in renderings by collecting professional realistic paintings of rendered materials. From both type of images, we collect human judgments of material properties and compute a variety of image features that are known to reflect material properties. Our study reveals that, despite important visual differences between the two types of depiction, material properties in paintings and renderings are perceived very similarly and are linked to the same image features. This suggests that we use similar visual cues independently of the medium and that the presence of such cues is sufficient to provide a good appearance perception of the materials.
University of Groningen Relationship satisfaction in couples confronted with colorectal cancer

Based on attribution theory, this study hypthesized that past spousal supportiveness may act as a moderator of the link between one partner’s current support behavior and the other partner’s relationship satisfaction. A sample of 88 patients with colorectal cancer and their partners completed questionnaires approximately 3 and 9 months after diagnosis. The data were analyzed employing dyadic data analytic approaches. In the short-term, spousal active engagement—which involved discussing feelings and engaging in joint problem solving—was positively associated with relationship satisfaction in patients as well as in partners, but only when past spousal support was relatively low. Spousal protective buffering—which involved hiding worries and fears and avoiding talking about the disease—was negatively associated with relationship satisfaction in patients, again only when past spousal support was relatively low. If past spousal support was high, participants rated the quality of their relationship relatively high, regardless of their partner’s current support behavior. Over time, past spousal supportiveness was not found to mitigate the negative association between spousal protective buffering and relationship satisfaction. Overall, our results indicate that relationship satisfaction can be maintained if past spousal supportiveness is high even if the partner is currently not very responsive to the individual’s needs, at least in the short-term.
Properties of high-temperature phase diagram and critical point parameters in silica

Some uncertainties are discussed on the high-temperature phase boundaries and critical point parameters for gas-liquid phase transition in silica (SiO2). The thermal and caloric phase diagrams are compared and examined as being predicted by various theoretical approaches, such as the quasi-chemical representation, the wide-range semi-empirical equation of state and the ionic model under direct molecular dynamic simulation. The theoretical predictions are confronted with handbook recommendations and scanty experimental data on the equilibrium vapor composition over SiO2 boiling. Validity of conventional semi-empirical rules is tested for the theoretically predicted SiO2-phase diagrams. The non-congruence of gas-liquid phase transition in SiO2 is considered for this matter to be used as a modeling body to study the non-congruent evaporation in uranium dioxide and other uranium-bearing fuels at both existing and perspective nuclear reactors.
A PRODUCTION PLANNING OF MIXED CHAMPIGNON PRODUCT

PT X is an agroindustry which focuses on the champignon commodities. Champignon has a short shelf life, so it must be sold directly to consumers or processed into champignon preserved products. The number of the champignon demand is uncertain causes excess or lack of stock on both fresh champignon and champignon preserved products. Therefore, it is necessary to calculate the product combination plan that can meet the desired objectives and obtain a satisfying solution. This study uses the goal programming method to make product combination planning. This study also used data of the products demand and raw materials from January 2017 to December 2019. In addition, data of man hours, production costs, and prices of each type of product were also used. Historical data of demand and raw materials were used to predict the level of products demand and raw materials in the planning period using ARIMA models. Determination of priority levels in the goal programming modeling of this study was done using pairwise comparison. Based on the planning results that has made for January 2020, the total production of fresh mushroom was 22,584 kg, 250 ml whole champignon was 4,499 pieces, 900 mL whole champignon was 2,571 pieces, 250 mL sliced champignon was 4,567 pieces, 900 mL of sliced champignon wass 32,306 pieces, and canned champignon was 85 pieces. The verification of the model showed that the forecast model used in this study was representative.
Management of technostress in teachers as an occupational risk in the context of COVID19

The integration of new technologies in schools and high schools are linked to new problems with the use and management of ITC tools as technostress between teachers. Technostress is associated with several negative effects on workers’ health as anxiety, musculoskeletal disorders, headache, mental and physical fatigue. Due to the worldwide COVID19 pandemic, the majority of schools blocked out, and face to face courses were transformed into online courses in a very short time. In these circumstances, several teachers were forced to increase their skills with ICT technology to accomplish their teaching objectives, and their technological workload was higher than at the beginning of the course. In the current research, the technostress of teachers was evaluated based on a validated questionnaire. Results pointed out that occupational risks linked to technostress were high during the pandemic period. Older teachers showed more vulnerability to the risk, because a lack of training and adaptation of some of the new tools for online courses, while women showed higher levels of anxiety and emotional tension. Prevention measures as specific training programs for ICT, rational use of ICT, and a more balanced distribution of work and family life at home should be developed to address the problem.
Optimal experiment design for bottom friction parameter estimation

It is common practice within numerical coastal ocean modelling to perform model calibration with respect to a bottom friction parameter. While many modelling studies employ a spatially uniform coefficient, within the parameter estimation literature the coefficient is typically taken to be spatially (or even temporally) varying. A parameter estimation experiment requires an appropriate set of observations, and also the selection of an appropriate parameter space which captures the spatial variability of the bottom friction parameter. In regions such as the Bristol Channel, which is used as a case study within this work, observation data is relatively abundant; here we use observations of M2 and S2 harmonic amplitudes and phases at 20 locations within the Channel. However, as is typical within friction parameter estimation problems, there is no obvious constraint on the spatial variation of the friction coefficient. Here, we define the parameter estimation ‘experiment design’ as the mapping from a small number of friction parameters onto the model domain. We propose a robust method for the appropriate selection of a low-dimensional experiment design, utilising an optimal experiment design (OED) technique via construction of the Fisher Information Matrix. The objective is to identify the experiment design resulting in the tightest possible constraints on the unknown parameters, given the available observation data. We construct the Fisher Information Matrix via the use of an adjoint shallow water numerical model, Thetis, and perform a variant of D-optimal design to find the optimal experiment design from within two a priori choices of design space. These are based on splitting the model domain either by simple slices across the channel, or by the type of sediment found on the sea bed. We first validate the OED framework by utilising a Bayesian inference algorithm to perform parameter estimation using a selection of experiment designs, which confirms that the OED framework offers a good estimate of the true parameter uncertainty resulting from the use of a given experiment design. An exploration of the full space of experiment designs shows that up to three Manning’s n coefficient values can be estimated from the observation data to within an uncertainty of approximately 0.001 s m−1/3, but that the experiment design is highly influential in achieving this threshold, thus demonstrating the value of our approach as a preliminary step in a parameter estimation study. We also investigate the sensitivity of the achievable parameter uncertainty to the availability of observation data and its measurement uncertainty, providing insights useful to the design of future observation surveys. Finally, we further demonstrate our OED framework with an application to a model of the northwest European continental shelf.
Zeeman term for the Néel vector in a two sublattice antiferromagnet

We theoretically investigate the dynamics of solitons in two sublattice antiferromagnets under external perturbations, focusing on the effect of Dzyaloshinsky-Moriya (DM) interactions. To this end, we construct a micromagnetic field theory for the antiferromagnet in the presence of the external magnetic field, DM interaction, and spin-transfer torque. In particular, we show external magnetic field and spin current couple to N\'eel vector in a Zeeman-like manner when DM interactions present, which can be used to efficiently drive antiferromagnetic solitons of different dimensions. Besides, we study the effect of straining the local lattice. It can serve as an external handle on the N\'eel field inertia and thus dynamical properties. Our findings may find applications in antiferromagnetic spintronics.
A Glivenko-Cantelli Bootstrap Theorem for the Foster-Greer-Thorbecke Poverty Index

Abstract.We assume the Foster-Greer-Thorbecke (FGT) poverty index as an empirical process indexed by a particular Glivenko-Cantelli class or collection of functions and define this poverty index as a functional empirical process of the bootstrap type, to show that the outer almost sure convergence of the FGT empirical process is a necessary and sufficient condition for the outer almost sure convergence of the FGT bootstrap empirical process; that is: both processes are asymptotically equivalent respect to this type of convergence.
Exploring bike-sharing systems in Poland co-financed from the European Union funds

In recent years, numerous Polish cities and municipalities have become involved in the creation of bike-sharing systems. Although the contribution of bike-sharing to creating sustainable transport caused some controversy in the literature, the positive role of cycling in promoting low-emission mobility and a healthy lifestyle is widely acknowledged. As part of the European Union’s sustainable transport agenda, some Polish local governments have obtained funding from structural funds for the implementation of bicycle-sharing schemes. This article presents an overview of selected systems, as well as a preliminary analysis of their users’ activity based on data obtained through a Web API. Although the scope of the data was limited in time due to the shutdown of the systems caused by the COVID-19 pandemic shortly after their spring reactivation, some patterns could be observed. In particular, users activity was more evenly distributed over time in larger cities (over 300 thousand of residents), whereas in smaller cities alternating periods of high and low activity was observed.