bluuebunny/crossref_metadata_2025_split huggingface dataset:
A-priori bounds for quasilinear problems in critical dimension
Authors: Romani Giulio 
Published: September 2019

AbstractWe establish uniform a-priori bounds for solutions of the quasilinear problems$$\begin{array}{} \displaystyle \begin{cases} -{\it\Delta}_Nu=f(u)\quad&\mbox{in }{\it\Omega},\\ u=0\quad&\mbox{on }{\partial{\it\Omega}}, \end{cases} \end{array}$$whereΩ⊂ ℝNis a bounded smooth convex domain andfis positive, superlinear and subcritical in the sense of the Trudinger-Moser inequality. The typical growth offis thus exponential. Finally, a generalisation of the result for nonhomogeneous nonlinearities is given. Using a blow-up approach, this paper completes the results in [1, 2], extending the class of nonlinearities for which the uniform a-priori bound applies.
Periodic solutions for second order differential equations with indefinite singularities
Authors: Lu Shiping , Yu Xingchen 
Published: September 2019

AbstractIn this paper, the problem of periodic solutions is studied for second order differential equations with indefinite singularities$$\begin{array}{} \displaystyle x''(t)+ f(x(t))x'(t)+\varphi(t)x^m(t)-\frac{\alpha(t)}{x^\mu(t)}+\frac{\beta(t)}{x^y (t)}=0, \end{array}$$wheref∈C((0, +∞), ℝ) may have a singularity at the origin, the signs ofφandαare allowed to change,mis a non-negative constant,μandyare positive constants. The approach is based on a continuation theorem of Manásevich and Mawhin with techniques of a priori estimates.
Concentration, Brine Salinity and Temperature effects on Xanthan Gum Solutions Rheology
Authors: de Moura Mateus Ribeiro Veiga , Moreno Rosângela Barros Zanoni Lopes 
Published: September 2019

Abstract
Xanthan gum is a biopolymer used in several different industries for a variety of applications. In the Petroleum Industry, xanthan gum has been applied in Enhanced Oil Recovery (EOR) methods for mobility control due to its Non-Newtonian rheological behavior, relative insensitivity to salinity and temperature compared to other conventional synthetic polymers, as well as its environmentally-friendly characteristics. As challenging reservoir conditions arise, candidate polymers should meet the screening factors for high salinity, high temperatures and heterogeneous reservoirs. This paper aims to evaluate the effects of temperature and monovalent salts on the rheological behavior of xanthan gum for Enhanced Oil Recovery purposes. We tested polymer solutions with brine salinities of 20,000/110,000/220,000 ppm of Sodium Chloride in a rheometer at temperatures of 23, 50, and 77°C. The results acquired showed that temperature plays a key role in viscosity and salinity protected the solution viscosity against negative thermal effects, unusually a turning point is observed where the increase in the monovalent salt content enhanced the polymeric solution viscosity. Such investigations coupled with a detailed discussion presented in the paper contribute to understand critical aspects of xanthan gum and its capability to provide basic requirements that fit desired screening factors for EOR.
Shear thinning and thickening of cemented paste backfill
Authors: Yang Liuhua , Wang Hongjiang , Wu Aixiang , Li Hong , Tchamba Arlin Bruno , Bier Thomas A. 
Published: September 2019

Abstract
Cemented paste backfill (CPB) is considered to be a concentrated suspension in which tailings are bonded together by the hydraulic binder and water, and it has a high solid volume concentration (≥50 vol.%). Although the shear thinning and thickening of CPB has been extensively reported in literature, the shear history effects have been ignored in previous studies. In this paper, by using rheometer and Focused Beam Reflectance Measurement, the relationship between the rheological properties and microstructure of the paste under different shear histories was studied. The results have shown that at a low shear rate, CPB revealed shear thinning, low yield stress and low index parameters; while exhibited shear thickening, high yield stress and high consistency index when at high shear rates of shear history. This agreed with the general trends shown in the FBRM analysis. It was proposed that the action of shear is beneficial to particle dispersion, whereas a high shear rate history tends to promote the aggregation of particles. It was revealed that both shear thinning and thickening of paste are related to the situation of particles (flocculation, dispersion and aggregation), and shear history effects play an important role in rheological properties of CPB.
Perturbed locations and linear stability of collinear Lagrangian points in the elliptic restricted three body problem with triaxial primaries
Authors: Rahoma Walid Ali , Masoud Akram , Abd El-Salam Fawzy Ahmed , Khattab Elamira Hend 
Published: September 2019

Abstract
This paper aims to study the effect of the triaxiality and the oblateness as a special case of primaries on the locations and stability of the collinear equilibrium points of the elliptic restricted three body problem (in brief ERTBP). The locations of the perturbed collinear equilibrium points are first determined in terms of mass ratio of the problem (the smallest mass divided by the total mass of the system) and different concerned perturbing factors. The difference between the locations of collinear points in the classical case of circular restricted three body problem and those in the perturbed case is represented versus mass ratio over its range. The linear stability of the collinear points is discussed. It is observed that the stability regions for our model depend mainly on the eccentricity of the orbits in addition to the considered perturbations.
Equilibria and orbits in the dynamical environment of asteroid 22 Kalliope
Authors: Jiang Yu , Li Hengnian 
Published: September 2019

Abstract
This paper studies the orbital dynamics of the potential of asteroid 22 Kalliope using observational data of the irregular shape. The zero-velocity surface are calculated and showed with different Jacobian values. All five equilibrium points are found, four of them are outside and unstable, and the other one is inside and linearly stable. The movement and bifurcations of equilibrium points during the variety of rotation speed and density of the body are investigated. The Hopf bifurcations occurs during the variety of rotational speed from ω=1.0ω
0 to 0.5ω
0, and the Saddle-Node bifurcation occurs during the variety of rotational speed from ω=1.0ω
0 to 2.0ω
0. Both unstable and stable resonant periodic orbits around Kalliope are coexisting. The perturbation of an unstable periodic orbit shows that the gravitational field of Kalliope is strongly perturbed.
Solar observations at the Coimbra Astronomical Observatory
Authors: Lourenço Ana , Carvalho Sara , Barata Teresa , Garcia Adriana , Carrasco Víctor , Peixinho Nuno 
Published: September 2019

Abstract
In 2020, the Geophysical and Astronomical Observatory of the University of Coimbra will celebrate the 95th anniversary of its first spectroheliographic observation. Keeping a daily service of solar observations since then, making almost a century, led to one of the largest continuous solar data collections in the world. This long–term solar database is essential for studies where solar activity is involved. This work reviews the development of synoptic observations made at the Observatory of Coimbra since 1925 and presents a summary of some of the principal stages of the Observatory’s history since its founding in 1772. We refer the main technical improvements and present some perspectives for the near future. One of the most significant upgrades was the installation of a CCD camera in 2007. The transition from photographic emulsion to digital recording methods allowed the development of image analysis algorithms to process solar images and improved data sharing with other institutions. This upgrade enabled also to carry–out modern climate and space weather studies. This valuable advancement makes it possible to create a new catalogue of solar observations to be published in the future.
Integral membrane protein expression of human CD25 on the cell surface of HEK293 cell line: the available cellular model of CD25 positive to facilitate in vitro developing assays
Authors: Dehbashi Moein , Hojati Zohreh , Motovali-bashi Majid , Ganjalikhani-Hakemi Mazdak , Shimosaka Akihiro 
Published: September 2019

AbstractTypically, CD25 is expressed on the cellular surface of regulatory T (Treg) cells. These cells are significant in regulating the self-tolerance and also preventing the immune system from attacking a person’s own tissues and cells. They promote the cancer progression by playing an important role in evading the immune system. Thus, the experimental procedures was aimed to clone and express human CD25 in HEK293 cell line, as the available cellular model, for the purpose of developing assays to facilitate and enhance the studies on an available CD25 positive cell. The secondary RNA structure of CD25 was evaluated by in silico analysis. Then, cDNA of human CD25 were synthesized from isolated total mRNA of cultured and stimulated PBMCs from blood donors. After cloning the cDNA of CD25 into a pcDNA3.1(+) plasmid, using the effective transfection of the recombinant pcDNA3.1(+) in HEK293, qRT-PCR and flow cytometry methods were used to quantitatively evaluate CD25 transcripts and protein level. There was a 4.8 fold increase in transcripts and a 76.2% increase in protein levels of CD25 when comparing the transfected and control cell lines. The genetically engineered HEK293 cell line expressing Treg cell surface marker of CD25 was introduced in this study for the first time. This cell line can be used to overcome the problematic issues for studying Treg cells including low population of Tregs in peripheral blood, low recovery methods for Treg isolation, time-consuming and non-cost benefit methods in the conditions of in vitro cell culture experiments for the studies focused on the binding of IL-2 to CD25.
Effective brain connectivity estimation between active brain regions in autism using the dual Kalman-based method
Authors: Rajabioun Mehdi , Motie Nasrabadi Ali , Shamsollahi Mohammad Bagher , Coben Robert 
Published: September 2019

Abstract
Brain connectivity estimation is a useful method to study brain functions and diagnose neuroscience disorders. Effective connectivity is a subdivision of brain connectivity which discusses the causal relationship between different parts of the brain. In this study, a dual Kalman-based method is used for effective connectivity estimation. Because of connectivity changes in autism, the method is applied to autistic signals for effective connectivity estimation. For method validation, the dual Kalman based method is compared with other connectivity estimation methods by estimation error and the dual Kalman-based method gives acceptable results with less estimation errors. Then, connectivities between active brain regions of autistic and normal children in the resting state are estimated and compared. In this simulation, the brain is divided into eight regions and the connectivity between regions and within them is calculated. It can be concluded from the results that in the resting state condition the effective connectivity of active regions is decreased between regions and is increased within each region in autistic children. In another result, by averaging the connectivity between the extracted active sources of each region, the connectivity between the left and right of the central part is more than that in other regions and the connectivity in the occipital part is less than that in others.
Predicting academic success through students’ interaction with Version Control Systems
Authors: Guerrero-Higueras Ángel Manuel , DeCastro-García Noemí , Rodriguez-Lera Francisco Javier , Matellán Vicente , Conde Miguel Ángel 
Published: September 2019

Abstract
Version Control Systems are commonly used by Information and communication technology professionals. These systems allow monitoring programmers activity working in a project. Thus, Version Control Systems are also used by educational institutions. The aim of this work is to evaluate if the academic success of students may be predicted by monitoring their interaction with a Version Control System. In order to do so, we have built a Machine Learning model which predicts student results in a specific practical assignment of the Operating Systems Extension subject, from the second course of the degree in Computer Science of the University of León, through their interaction with a Git repository. To build the model, several classifiers and predictors have been evaluated. In order to do so, we have developed Model Evaluator (MoEv), a tool to evaluate Machine Learning models in order to get the most suitable for a specific problem. Prior to the model development, a feature selection from input data is done. The resulting model has been trained using results from 2016–2017 course and later validated using results from 2017–2018 course. Results conclude that the model predicts students’ success with a success high percentage.
Modeling concepts and their relationships for corpus-based query auto-completion
Authors: Rossiello Gaetano , Caputo Annalina , Basile Pierpaolo , Semeraro Giovanni 
Published: September 2019

AbstractQuery auto-completion helps users to formulate their information needs by providing suggestion lists at every typed key. This task is commonly addressed by exploiting query logs and the approaches proposed in the literature fit well in web scale scenarios, where usually huge amounts of past user queries can be analyzed to provide reliable suggestions. However, when query logs are not available, e.g. in enterprise or desktop search engines, these methods are not applicable at all. To face these challenging scenarios, we present a novel corpus-based approach which exploits the textual content of an indexed document collection in order to dynamically generate query completions. Our method extracts informative text fragments from the corpus and it combines them using a probabilistic graphical model in order to capture the relationships between the extracted concepts. Using this approach, it is possible to automatically complete partial queries with significant suggestions related to the keywords already entered by the user without requiring the analysis of the past queries. We evaluate our system through a user study on two different real-world document collections. The experiments show that our method is able to provide meaningful completions outperforming the state-of-the art approach.
Moment Problems in Hereditary Function Spaces
Authors: Vasilescu Florian-Horia 
Published: September 2019

Abstract
We introduce a concept of hereditary set of multi-indices, and consider vector spaces of functions generated by families associated to such sets of multi-indices, called hereditary function spaces. Existence and uniquenes of representing measures for some abstract truncated moment problems are investigated in this framework, by adapting the concept of idempotent and that of dimensional stability, and using some techniques involving C*-algebras and commuting self-adjoint multiplication operators.
Modelling of Thermodynamic Pressure – Composition – Temperature Relationships in the Systems of Metallic Hydride Forming Materials with Gaseous Hydrogen Using C++ Software
Authors: Moropeng Mapula Lucey , Kolesnikov Andrei , Lototskyy Mykhaylo , Mavhungu Avhafunani 
Published: September 2019

Abstract
In this paper, the solution of the Lacher model describing the relationship between the Pressure – Composition, and Temperature (PCT diagrams) of AB5 type metal-hydrides (LaNi4.8Sn0.2, LmNi4.91Sn0.15, LaNi4.5Al0.5) for hydrogen storage using C ++ platform, with the help of a numerical method of nonlinear equation, Newton-Raphson method is presented. This study focuses on the development of a C ++ code to describe the iteration of Newton-Raphson for application in Hydrogen to Metal-Hydride systems.
When Students Design University: a Case Study of Creative Interdisciplinarity between Design Thinking and Humanities
Authors: Molinari Alessandra , Gasparini Andrea Alessandro 
Published: September 2019

AbstractThis paper addresses the issue of how to enhance student participation in university governance. This issue is approached by taking into account the growing pressures of the European Commission’s modernization agenda on the educational policies of the European Higher Education Area, and by focusing on the way these pressures affect students’ conceptions of themselves and of the mission of higher education. The thesis presented in this paper is that design thinking and the humanities share a common epistemological core that enables them, if applied in educational settings, to play a major role in fostering students’ trust in their governance skills and in their ability to influence educational policies through a creative mindset and a deeper comprehension of the stakes in present-day higher education. An experimental workshop combining design thinking with the humanities and with the constructivist approach of student-centered learning was held within a course in a humanities bachelor program on the basis of a heuristic framework developed through an interdisciplinary research process. This process was conducted according to the principles of design and hermeneutics. The outcomes of the workshop in terms of the participants’ enhanced self-confidence and decisional skills validate the thesis of this study.
Shedding Light on the Convoluted Terrain of Differentiated Instruction (DI): Proposal of a DI Taxonomy for the Heterogeneous Classroom
Authors: Pozas Marcela , Schneider Christoph 
Published: September 2019

Abstract
Student heterogeneity is not limited to performance, but encompasses cultural background, language competence, learning styles, and motivation. Thus, heterogeneity inherently changes the demands placed on teachers and requires them to practice differentiated instruction (DI). However, existing DI frameworks tend to describe single exemplary DI practices and widely lack an empirical view. Thus, these frameworks may provide little help to classroom teachers when it comes to the question of how or by which instructional arrangements they can address student heterogeneity in their everyday classroom teaching. In an attempt to bridge the gap between educational theory and everyday instructional practice, this theoretical paper focusing on differentiation within secondary school education proposes a comprehensive taxonomy of the DI practices known in the literature and practice. Outlines for future research on DI are discussed.
Curves on Segre threefolds
Authors: Ballico Edoardo , Chung Kiryong , Huh Sukmoon 
Published: September 2019

Abstract
We study locally Cohen–Macaulay curves of low degree in the Segre threefold

ℙ
1

×

ℙ
1

×

ℙ
1

{\mathbb{P}^{1}\times\mathbb{P}^{1}\times\mathbb{P}^{1}}

and investigate the irreducible and connected components, respectively, of the Hilbert scheme of them.
We also apply the similar argument to the Segre threefold

ℙ
2

×

ℙ
1

{\mathbb{P}^{2}\times\mathbb{P}^{1}}

.
Outlook for modified wood use and regulations in circular economy
Authors: Heräjärvi Henrik , Kunttu Janni , Hurmekoski Elias , Hujala Teppo 
Published: September 2019

AbstractCircular economy may play a key role in the future success of modified wood products. The European Union (EU) aims toward a circular economy, i.e. increasing resource efficiency by waste minimization in production processes, cascade uses of materials, elimination of landfill wastes, and maximizing the value of raw materials. The policy has great expected impact across all sectors, and will influence countries with strong wood modification industries, such as Finland, Germany, Norway, and the Netherlands. It also means considerable economic efforts and sets transformation challenges to the societies and industries. Challenges have country-wise differences depending on production structure, environmental circumstances, local policies and regulations, as well as economic resources. This paper is an outlook of the renewed waste legislation in the EU, based on which it assesses the possible impacts of circular economy development on the future of wood modification. One of the key indicators for resource efficiency is € kg−1, which allows pursuing increased efficiency by minimizing material input (and waste) and/or by maximizing the value. In the case of modified wood, both of these approaches may be considered market opportunities, while the key challenge and the consequent need for action relate to improved waste management.
PV-Battery Hybrid System with Less AH Capacity for Standalone DC Loads
Authors: Kolakaluri Vinay Kumar , Vyjayanthi C. , Mikkili Suresh 
Published: September 2019

Abstract
Partial Shading Condition (PSC) is one of the key issues faced by Solar Photovoltaic (PV) systems. PSCs mainly occur due to clouds, shadows of trees/buildings, dust and so on. During the PSC, the shaded PV module acts like a sink and absorbs the power from highest irradiated modules in a string and leads to hotspot. This situation is highly vulnerable and has to be avoided. Bypass diodes are used in series configured PV modules to overcome the hotspot effect caused due to PSC. However, the use of bypass diodes leads to multiple peaks in the Power-Voltage (P-V) graph of a PV array. One among them is Global peak point, where PV array needs to operate under PSC. In such a case, some amount of power generated by the shaded modules gets wasted, which will lead to poor performance and efficiency of the overall system. Moreover, for standalone DC load applications an auxiliary supply also required to provide reliable supply to the load during night times and PSC. Normally, batteries are used in standalone systems as an auxiliary supply. To control the charging and discharging process of battery a bi-directional DC-DC converter is used as a charge/discharge controller. The amount of power that is being charged/discharged by batteries depends upon the load requirement and solar power availability. Under PSC, due to lack of extraction of PV power from shaded modules, batteries have to supply the deficient power to the load. This situation forces to increase the AH capacity of the battery to provide reliable supply. In this research article PV-Battery Hybrid system is proposed to improve the performance of PV under varying irradiance and load conditions with reduced AH capacity of battery for standalone DC loads. The performance assessment of proposed topology has been carried out with the comparison of percentage improvement in power extraction, percentage reduction in the average current consumption of battery and SoC delivered by battery with conventional methodologies of bypass diode and proposed methodology under PSC. The assessment is carried out on MATLAB/SIMULINK and results are presented.