bluuebunny/crossref_metadata_2025_split huggingface dataset:
La habitación popular moderna en Guadalajara. Permanencias y transformaciones
Authors: Rueda Velázquez Claudia 
Published: January 2020

<p>Entre el periodo de 1947 a 1954 en la ciudad de Guadalajara, Jalisco, se instrumentaron dos programas para tratar de subsanar la escasez de vivienda para trabajadores. El primero, fue el Patronato de la Habitación Popular y el segundo, Pensiones del Estado de Jalisco. Estos dos organismos plantearon, desde una visión moderna y a su vez localista, proyectos arquitectónicos que ayudaron a configurar la capital tapatía. Este artículo revisa los dos primeros proyectos de ambas instituciones buscando, desde el análisis de proyecto, sus similitudes y divergencias. Los términos “permanencias y transformaciones” responden a las ideas arquitectónicas que permanecen y que se han transformado en ambos proyectos para adaptarse a la época actual. Además de ello, el artículo intenta poner en valor estos proyectos poco conocidos donde colaboraron arquitectos como Ignacio Díaz Morales y José Villagrán García.</p>
Investigation of Dynamic Buckling of a Wing Model in Air Flow
Authors: Naumov A. M. , Mochilin I. K. 
Published: January 2020

The paper deals with studying a dynamic stability of the wing model in the ram airflow. As known, at a certain flow rate that is called critical, there is a phenomenon of self-excited non-damping flexural-torsional self-vibrations, named flutter. A two-mode elastic system wing model is under consideration, as is common in the literature in the field concerned. The paper continues and develops investigations of well-known scientists in this field, such as V.L. Biderman, S.P. Strelkov, Ya.G. Panovko, I. I. Gubanova, E.P. Grossman, J.Ts. Funen, etc. A great deal of papers dedicated to this problem and published by abovementioned and other scientists, give only the problem formulation and the derivation of equations, often in a fairly simplified form, do not offer solutions of these equations for specific numerical parameters of the wing model, and do not study how these parameters affect the flutter onset velocity.The paper details the derivation of linear differential equations of small vibrations of the wing model in the flow, determines the natural frequencies and shapes of flexural-torsional vibrations, checks their orthogonality, studies vibrations under the influence of aerodynamic force and moment, determines the critical flow velocity for a number of system parameters, and draws a conclusion about the influence of these parameters on the critical velocity. In particular, it studies how such a parameter as the distance between the center of gravity and the center of stiffness affects the critical velocity, as well as how the stiffness of the model's spring suspension, which simulates the stiffness characteristics of the wing impacts on bending and torsion. The calculation results allow us to draw conclusion concerning the methods of dealing with this phenomenon. One of the promising options may be, in addition to varying the geometric and rigid parameters of the system, the introduction of additional mass to be an analogue of the vibration damper. The paper may be of interest both for engineering students who learn the theory of mechanical vibrations, and for engineering-specialists in aero-elasticity and dynamic stability of elements in mechanical systems.
Absorption-based Mono-ethanolamine Treatment of Associated Petroleum Gas. Part 1
Authors: Golovastov S. V. , Alexandrova D. M. 
Published: January 2020

The paper presents an absorption-based method to treat associated petroleum gas (APG) using the mono-ethanolamine (MEA) as an absorbent. Involving oiler’s specific data in the southern regions of Russia, an APG treating unit has been developed to take out hydrogen sulfide. The extracted hydrogen sulfide can be used to obtain elemental sulfur. The development object is a treating APG unit.The work objective was to develop an absorber for APG treating to take out hydrogen sulfide by means of regenerated MEA aqueous solution. The work was aimed at reducing environmental pollution when using associated petroleum gas as an energy utility.A plate-shaped absorber model was used. In this design, the liquid enters the upper plate, moves horizontally along the plates, from the overflow from the overlying one towards the overflow to the underlying one, and outlets through the lower part of the absorber.The paper offers an option of the unit for APG treating for removing hydrogen sulfide with the elemental sulfur further produced by the Claus process to solve this problem through using APG as an industrial and domestic gas.The work has involved a complete calculation of the two-component absorption process, a design calculation of the plate-shaped absorber, in particular, determination of the cowl wall thickness, a fitting selection, a calculation of the foundation bolts taking into account the wind load on the absorption column, a rationale for the option chosen, and a calculation of the complete desorption process.In entering the desorber, the absorbent undergoes a single liquid and vapour phase evaporation. To calculate a mole fraction of the stripping initial absorbent, as well as phase compositions, is used a Tregubov method.
Transversely Isotropic Rod for Modeling Elastic Characteristics of Single-Walled Carbon Nanotube
Authors: Zarubin V. S. , Sergeeva E. S. 
Published: January 2020

Single-walled carbon nanotubes (SWCNT) are a seamless cylindrical structure formed by folding a single-walled graphene sheet. Nanotubes are of great interest due to their unique thermo-mechanical characteristics. Such objects can be applied in the energy, rocket and aerospace engineering as a filler of advanced structural composite materials.One of the most important SWCNT characteristics is a complex of its elastic properties. The most reliable way to determine the elastic characteristics of a nanotube is to conduct an experiment. However, due to high cost and lengthy time of the experiment completion, it is more preferable to use mathematical modeling of these properties of SWCNT with which the paper deals.The paper proposes a mathematical model that is constructed by methods of generalized continuum mechanics. To use these methods, the nanotube, on the assumption of its transverse isotropy, is presented simultaneously as a cylindrical shell and a continuous circular rod.As a result of consideration of various stress-strain states of the shell and rod, are obtained relations to establish a quantitative relation between the elements of the matrix of compliance coefficients of a rod that simulates a single-walled carbon nanotube, and the elastic characteristics of graphene taken as its basis in the isotropy plane. Also, the constructed mathematical model allows us to define the influence of the nanotube configuration (chiral indices) on its elastic characteristics.The paper presents the application results of the model proposed, using as an example, a SWCNT with chirality indices (7, 0), for which were constructed mutually inverse matrices of compliance and elasticity coefficients that completely describe the elastic properties of the nanotube.Using the proposed mathematical model significantly reduces the time and cost for estimation of the elastic characteristics of the SWCNT, that is especially important at the design stage of new materials based on them.
Some Study Methods for Ordinary Differential Equation Integrability of the Second Order of a Certain Type
Authors: Zadorozhnaya O. V. , Kochetkov V. K. 
Published: January 2020

The paper deals with treating some study methods of the equation integrability of a certain type that are little studied in the theory of differential equations. It is known that a significant part of the differential equations cannot be integrated. Then, to develop methods for their study is, certainly, of scientific interest. The obtained results, formulated as theorems and statements, are of scientific and practical interest because of their importance for applications in modern science.In the paper we present an alternative method for studying the integrability of both linear and nonlinear differential equations of the second order. An introduction of parameters allowed us to develop a study method for the integrability of ordinary differential equations of the second order. We also formulate the theorems describing some General conditions for the integrability of the second-order linear equation and consider special cases of integrability, which arise out of the above facts.Based on the obtained parameter method, some General conditions for the integrability of the nonlinear differential equation of the second order are given, and the consequences of these General conditions are indicated.We have obtained new results related to the construction and development of methods for studying the differential equation to which some types of differential equations are reduced and laid the foundations for a rigorous and systematic study of the introduced special nonlinear differential equation of the second order.
Fractional-Differential Model of Heat Conductivity Process in Ferroelectrics under the Intensive Heating Conditions
Authors: Moroz L. I. , Maslovskaya A. G. 
Published: January 2020

Ferroelectrics, due a number of characteristics, behave as hereditary materials with fractal structure. To model mathematically the systems with so-called memory effects one can use the fractional time-derivatives. The pyro-electric properties of ferroelectrics arouse interest in developing the fractional-differential approach to simulating heat conductivity process.The present study deals with development and numerical implementation of fractal heat conductivity model for hereditary materials using the concepts of fractional-differential calculus applied to the simulation of intensive heating processes in ferroelectrics.The paper proposes a mathematical model governed through mixed initial-boundary value problem for partial differential equation containing a fractional time-derivative as well as nonlinear temperature dependence on the heat capacity. To solve the problem the computational algorithm was designed which is based on an analog of the Crank – Nicolson finite difference scheme combining with the Grunwald – Letnikov formula for fractional time-derivative approximation. The approximation of Neumann boundary condition is included into the finite difference problem statement using scheme of fictitious mesh points. The total system of linear algebraic equations is solved by sweep method.The designed application program allows one to perform the computer simulation of heat conductivity process in hereditary materials. The model verification was performed for numerical solving test problem with known analytical solution. The results of computational experiments are demonstrated for the example of estimating heat distribution in a typical ferroelectric crystal of TGS (triglycine sulfate) near the temperature of phase transition. The fractional derivative order was approximately evaluated to be ~0.7 at variation of this parameter. We applied the comparison of fractal model implementation results with experimental data related to the time when the ferroelectric crystal is heated to Curie temperature. These findings demonstrate that one needs to use the modified models at the analysis of the field effects arising in hereditary materials.
Responding to emergencies: There’s an app for that.
Authors: Wood Brendan 
Published: January 2020

Our cellphones have become more than just a communication tool. This presentation will explore the use of cellphone applications in the emergency response and prehospital care within New Zealand. Three distinct groups of applications are identified. The first are apps used by community first responders, the second group, are apps used by paramedics in the prehospital environment, and finally apps which we can all use in disaster preparation and response. These apps also support the education of paramedicine students when they are undertaking simulations and planning exercises.
Real interest rate differentials between Central and Eastern European countries and the euro area
Authors: Janus Jakub 
Published: January 2020

Research background: The question of changes in real interest rates differentials between the Euro Area and the CEE countries in the last years is raised because of two main reasons. The first rationale is related to the growing importance of external financial factors for the CEE economies and their monetary autonomy. The second reason is associated with the unprecedented shift in monetary conditions in the EMU, brought about by negative interest rates policy and unconventional policies, and the way it impacts the real rates in the CEE economies.
Purpose of the article: This paper aims at exploring the relationship between real interest rates in the Euro Area and ten countries: Albania, Bulgaria, the Czech Republic, Hungary, North Macedonia, Moldova, Poland, Romania, Turkey, and Ukraine. The analysis covers the years of 1999-2018, including periods before and after the financial and economic crisis.
Methods: We employ Markov-switching regression to construct the ex-ante real interest rates series in each country, using monthly data on short-term interest rates and CPI inflation rates. A battery of unit root and stationarity test, both standard and panel ones, is applied to examine the real interest rate parity, also allowing for a structural break in the rate differentials.
Findings & Value added: We provide detailed evidence on the real interest rates differentials for all of the CEE countries vis-?-vis the Euro Area. We find that, while panel stationarity tests point to the stability of real rate differentials, there are significant dissimilarities across the countries, and the results of the univariate tests are often mixed. At least half of the economies, however, reveal similar patterns of stationarity in real rates relationships. At the same time, we find differentials for the Czech Republic, Hungary, and Poland, countries highly integrated into the EMU economy, to be unstable over time.
Site Specific Calibration Curve And Its Implication in The Treatment Planning of Head And Neck Cancer.
Authors: Srivastava Roopam , Gaur Shiva , Sharma Pramod , Sharma Manoj , Manjhi Jayanand , Das Maria , Chauhan Dr Deepika , Sehgal Dr Neha 
Published: January 2020

Purpose: In this study, we created site specific Hounsfield Unit (HU) and Relative electron density(RED) calibration curves for computed tomography(CT) and cone beam computed tomography (CBCT) for head and neck radiotherapy dose calculation and compared them with standard calibration curves.
Methods:
The calibration curves between HU and RED were generated using RANDO phantom for CT and CBCT and fed in the treatment planning system for dose calculation for head and neck patients.The treatment plans for 10 head and neck cancer patients were calculated using the standard calibration curves generated with CATPHAN and head and neck calibration curves generated with RANDO phantom for both CT and CBCT. Dose accuracy of head and neck calibration curves(H/N CC) were compared to the standard calibration curves (SCC) using dose volume metrics and 3D gamma analysis.
Results: The results show that slightly better dosimetric agreement from the SCC can be obtained when using this H/N CC.
Conclusions: A site specific calibration curves have been proposed and tested for the head-and-neck patients and the results explain the dosimetric benefits.
Enhance the Gas Productivity for Shale Gas Reservoirs Using Thermochemical Treatment
Authors: Hassan Amjed , Mahmoud Mohamed , Al-Majed Abdulaziz , Al-Nakhli Ayman 
Published: January 2020

In shale reservoirs, the gas productivity is severely reduced due to the formation tightness. The extreme low permeability of shale formations can result in reducing the gas flow into the borehole, and consequently the gas production can be significantly reduced. This paper presents an effective technique for enhancing the gas productivity for shale gas reservoirs using thermochemical fluids. The used chemicals can generate heat and pressure in-situ and improve the flow condition by creating micro- factures in the shale rocks. Experimental measurements and analytical calculations were carried out to investigate the enhancement in gas productivity for shale samples due to the injection of thermochemical fluids.
Coreflooding experiments and rate transient analysis (RTA) were conducted as well as nuclear magnetic resonance (NMR) measurements. Tight core samples from eagle ford formation were used in the flooding experiments. The improvement in gas productivity due to thermochemical injection was evaluated using rate transient analysis. The profiles of pressure-drop and gas flow-rate were used to estimate the gas productivity before and after the chemical treatment. NMR measurements were used to study the changes in the pore network due to thermochemical stimulation. The T2 signal distribution was obtained before and after the chemical injection. Furthermore, analytical calculations were performed to estimate the enhancement in gas productivity due to the thermochemical treatment. The increase in absolute open flow (AOF) and the productivity index (PI) due to the chemical treatment were determined.
Results showed that treating shale rocks with thermochemical fluids can enhance the gas productivity by 62% and reduce the capillary pressure by more than 45%. Also, the absolute open flow can be increased four times due to the thermochemical injection into shale reservoirs. The generated heat and pressure due to thermochemical treatment can induce permanent alterations in the shale matrix and then improve the hydrocarbon flow for long term. NMR measurements, before and after the treatment, confirm the creation of tiny fractures during the chemical injection. The novelty of this work is that an effective treatment is presented to enhance the gas productivity for shale formations. Ultimately, this study will be very useful for treating the shale reservoirs with thermochemical fluids to improve the gas productivity, and consequently enhance the total gas production from shale reservoirs.
Digitizing Chemical Data for Real Time Flow Assurance
Authors: Lovell John , Kulbrandstad Omar , Madem Sai , Meza Daniel , Babakhani Aydin 
Published: January 2020

By minitiaturzing and ruggedizing laboratory equipment historically used for geochemical applications, it is now possible to digitize chemical attributes of molecules as they flow through the wellhead. Specifically, the number of unpaired electrons in outer-orbitals can be tracked in real-time as well as the hyperfine interaction of those electrons with spin-properties of nuclei within their associated molecules. This sounds very esoteric but in fact has a direct relationship with traditional flow assurance problems that have previously been very difficult to manage. For example, considering those electrons which correspond to free radicals within asphaltene molecules, then, in the presence of a very strong magnetic field, they will resonate at a specific microwave frequency. By exposing the well fluid to exactly that combination of magnetic and RF fields, the amplitude of the resonance is proportional to the number of asphaltene molecules. Unlike some optical and infra-red techniques, this gives a measurement of the total amount of asphaltene flowing, not just a measurement of the non-dissolved component. This measurement can be made continuously, so that gives a time-series analysis of the percentage of asphaltene that is flowing in the oil. AI-based software has also been written to extract further information from the resonance data, such as the water-cut and gas-oil ratio. Operators can use this combined information to optimize their flow-assurance strategies, for example, to give immediate feedback on the result of changing an inhibitor or dispersant.
An initial version of the tool was deployed for a field-test in Abu Dhabi in Q4, 2017. Data from the system was transmitted via the cloud to asphaltene experts remotely monitoring the data. The resolution of the device proved better than expected, which allowed the system to give a previously unseen dynamic view of asphaltene chemistry. One surprise was that the asphaltene percentage might vary significantly over the course of a few hours, even when the surface pressure and flow-rates stayed the same. Troublesome wells had the highest standard deviation which gives a new key performance indicator (KPI) for flow assurance risk. Another unexpected result was that surface asphaltene levels would drop for a few days after a xylene soak, before slowly returning back to their baseline. This indicates that a freshly-cleaned tubular is more attractive for asphaltene deposition, and stays that way until a sufficiently thick asphaltene coating has accumulated.
Based on these results, additional hardware has been delivered to Abu Dhabi to begin a long-term pilot study on the use of electron resonance data for asphaltene management. Moreover, the device opens up to the oilfield traditional laboratory uses of electron resonance such as identification of kerogen maturity and geochemical rock typing.
Researching and Testing on Casing Ball Seat for Multistage Fracturing in Horizontal Wells
Authors: Liu Zhongneng , Wang Zhiguo , Ren Guofu , Guo Siwen , Gui Jie , Ren Yong , Xue Xiaowei , Zhao Minqi , Feng Changqing 
Published: January 2020

Plugs have been widely used for staged fracturing in horizontal wells. But in wells with long lateral or low reservoir pressure, plug milling are far more complex due to debris accumulation and fluid loss.
This study proposed a new multistage fracturing solution for horizontal wells using one kind of ball seat. Researchers have designed mechanical model of the seat. Metal material with great flexibility has been selected out and processed into seats according to the model. The key tools such as elastic seat, large-diameter soluble ball and the matching tools such as cylinder and launching tool were developed. The results of indoor tests and large-scale simulation tests of real parameters have shown that the seat has the capability of repeated rebounding and the capacity of pressure bearing and packing reaches 70MPa. Field tests of 12 horizontal wells, containing totally 115 stages, have been carried out and achieved the technological goals of infinitely large-scale staged fracturing, no milling, and nearly full-bore access. The fracturing cycle has been shortened by more than 30% and the operation cost of single well has been reduced by more than 15%.