bluuebunny/crossref_metadata_2025 huggingface dataset:
Silica-based Composite Membranes for Methanol Fuel Cells Operating at High Temperature
Authors: Alvarez A. , Guzman C. , Peza-Ledesma C. , Godinez Luis A. , Nava R. , Duron-Torres S. M. , Ledesma-Garcia J. , Arriaga L. G.
Published: August 2018

In this work, composite membranes were prepared from a mixture of Nafion® ionomer with mesoporous (SBA-15) and microstructured silica (SiO2). The silica-based materials were synthesized using the sol-gel technique and their properties were characterized by TEM, BET, SEM and XRD. A glass cell with two chambers was used to evaluate the permeability of methanol of the composite membranes and its performance was compared with a commercial Nafion 115 membrane. The composite membranes showed smaller value of methanol permeability (around 19%) than that obtained when was used a commercial membrane. In terms of the fuel cell performance, the composite membranes showed a larger maximum power density (62 and 29 mWcm-2 for the SiO2 and SBA-15 composite membrane respectively) than that obtained for the commercial membrane at high temperature conditions (100°C).
Evaluation of a ZrO2 Composite Membrane in PEM Fuel Cells Operating at High Temperature and Low Relative Humidity
Authors: Guzman C. , Alvarez A. , Godinez Luis A. , Herrera O. E. , Merida W. , Ledesma-Garcia J. , Arriaga L. G.
Published: August 2018

A composite membrane containing ZrO2 was tested under simulated and real fuel cell operations. To simulate the fuel cell environment, the composite membrane was tested on a gated cell at low relative humidity (10 %) and high temperature (100 °C). The water flux on the composite membrane was found to be higher than a commercial membrane (Nafion 115), suggesting that under these conditions water molecules are entrapped into the membrane matrix via dipole – dipole interactions. Under real operation conditions, ZrO2 membranes showed better performance at high temperature (140 °C) and low relative humidity (22.9 %) than the commercial Nafion Membrane. The performance results confirmed that composite membranes retain water and help to maintain the membrane hydration. The aging cycle (1750 cycles) showed that the composite membrane under study is stable under extreme operation conditions (22.9% RH and 120 °C).
Dynamic Model of a PEM Electrolyzer based on Artificial Neural Networks
Authors: Chavez-Ramirez A. U. , Munoz-Guerrero R. , Sanchez-Huerta V. , Ramirez-Arredondo Juan M. , Ornelas R. , Arriaga L. G. , Siracusano S. , Brunaccini G. , Napoli G. , Antonucci V. , Arico A. S.
Published: August 2018

Hydrogen production by electrolysis is emerging as one of the most promising ways to meet future fuel demand; likewise, the development of models capable of simulating the operation of electrolysis devices is indispensable in the efficient design of power generation systems, reducing manufacturing costs and resources savings. The nonlinear nature of the Artificial Neural Network (ANN) plays a key role at the development of models for predicting the performance of complex systems. The behavior of a Polymer Electrolyte Membrane (PEM) Electrolyzer of three cell stack (100 cm2 of active area) was modeled successfully using a Multilayer Perceptron Network (MLP). This dynamic model has been trained to learn the internal relationships that govern this electrolysis device and predict its behavior without any physical equations. The electric current supply and the operation temperature were used as input vector able to predict each cell voltage behavior. A reliable accuracy (< 2%) was reached in this work after comparing the single cell performance of the real electrolyzer versus the ANN based model. This predictive model can be used as a virtual device into a more complex energy system.
Oxygen Reduction Studies on Carbon-supported Pt-M Catalysts (M: Ru, W, Mo)
Authors: Maya R. Hernández , González A.J. Armenta , Ugalde O. , Guzmán M.T. Oropeza , Roquero P.
Published: August 2018

The activities of a series of carbon-supported bimetallic catalysts, with different active phases loadings, were tested towards the oxygen reduction reaction (ORR). Pt was used in all materials and its loading was kept constant. Mo, W and Ru were used as promoting phases. Rotating Disk electrode experiments revealed that Pt-Ru displayed the best performance in oxygen reduction among the studied materials. The materials with the highest loadings of the second metal revealed the highest activities. X-Ray Diffraction studies (XRD) and Transmission Electron Microscopy (TEM) revealed the presence of homogeneously dispersed metallic ruthenium and different tungsten or molybdenum oxides in the corresponding catalysts. No evidence of alloying was found, and thus the catalytic performances appear to be related to the distribution and interaction of the active phases.
Electrochemical Response to Dissolved Hydroquinone on Insulating Polyaniline-modified Electrode in Less Acidic Solution and Enhancement of the Conductivity of Polyaniline
Authors: Yano Jun
Published: August 2018

A conductive polymer, polyaniline (PANI), was easily prepared on an electrode surface as a stable film by the electropolymerization of aniline in acidic solution. In McIlvain’s buffer solution with a pH that exceeded 4, no redox current by the dissolved species was observed on the PANI-modified electrode because PANI acted as an electric insulator. However, in a less acidic solution, the redox current of the dissolved hydroquinone was evident because hydroquinone selectively permeates through the PANI film to reach the electrode substrate. The results of steady-state current-potential curves for the oxidation of hydroquinone using a PANI pellet electrode revealed that hydroquinone was concentrated in the PANI during the electro-oxidation. Furthermore, the concentration of hydroquinone increased the electric conductivity of the PANI from 6.50×10-7 S/cm to 2.73×10-3 S/cm.
Synthesis and Characterization of RuO2 Anode Materials with Large Surface Areas for Oxygen Evolution Reaction
Authors: Zhang Yang , Yue Lixia , Teng Ke , Yuan Shiyong , Ma Hongchao
Published: August 2018

A novel olivary or petal-like RuO2 material with large surface area was successfully synthesized by surfactant-assisted homogeneous precipitation method using urea and dodecyl sulfate as the source reagent. The surface morphology, structural, and electrochemical properties of as-synthesized RuO2 materials were characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Cyclic voltammetry (CV), N2 adsorption–desorption isotherms and polarization curve for oxygen evolution reaction (OER). It was found that the morphology and crystalline structures and electrochemical properties of as-synthesized RuO2 materials were strongly dependent on the calcining temperature. The ruthenium-surfactant mesophase with mesoporous structure transformed from network to regular olivary or petal-like RuO2 materials and remaining partial mesoporous character after calcination at lower temperature (i.e., 300 and 400 °C). However, the mesophase transformed into RuO2 agglomeration consisted of nanosized particles after calcination at 650 °C, which may be attributed to complete deorganization and porous structure collapse of RuO2 materials. In addition, the as-synthesized RuO2 materials showed higher specific surface area and better electrochemical activities for oxygen evolution reaction compared with the RuO2 prepared without surfactant. The electrochemical activity of as-synthesized RuO2 material calcined at 400 °C is about 3 times than that of RuO2 prepared without surfactant for oxygen evolution reaction. This can be attributed to the porous structure and large surface area of as-synthesized RuO2 materials.
Sulfolane as Solvent for Lithium Battery Electrolytes
Authors: Sedlarikova M. , Vondrak J. , Maca J. , Bartusek K.
Published: August 2018

The properties and applications in lithium batteries of solutions containing lithium perchlorate dissolved in sulfolane have been studied. Due to the high cryoscopic constant of sulfolane (85 K/mole), the freezing point can be considerably decreased. Also the viscosity can be decreased in a way similar to the idea of mixed carbonate solvents. Viscosity and conductivity obey the mified Walden rule. The addition of sulfolane to carbonate solvents increases their flash point fairly considerably.The capacity of experimental cells containing a LiCoO2 cathode and a carbon anode was ca. 33.33 mAh/g (related to anode material). The internal resistance of the cell increased, and an irreversible charge was observed on discharge curves and described. To some extent, the battery had the capability of a rechargeable one.

The use of sulfolane (SL) as a highly polar solvent for electrochemical purposes has been the subject of previous studies [1] – [6]. Its advantages are high permittivity, excedent thermal stability and resistance to strong oxidation potentials. However, there are some disadvantages such as rather high viscosity and correspondingly also low conductivity of salt solutions in this solvent, and a rather high freezing point (+ 28.4 °C).

A similar problem arises in ethylene carbonate which exhibits excellent electrochemical properties if solvents with a sufficiently low freezing point and viscosity are added. It is commonly known that the loss of conductivity is not so detrimental , and the freezing point depression can make such mixed solvents useful. Therefore the blends of ethylene carbonate (abbreviated as EC) with other solvents (mostly dimethyl carbonate DMC) are used as solvents for preparation of electrolytes for lithium batteries.

The main objective of the present paper is to attempt to suppress the weaknesses of sulfolane by adding a solvent with a sufficiently low freezing point and viscosity in order to facilitate the use of sulfolane for various electrochemical applications in electrochemical science and technology.
Electrochemical Study of a Nano Vesicular Artificial Peroxidase on a Functional Nano Complex Modified Glassy Carbon Electrode
Authors: Yang Wei-Yun , Hong Jun , Zhao Ying-Xue , Xiao Bao-Lin , Gao Yun-Fei , Yang Tian , Moosavi-Movahedi Ali Akbar , Ghourchian Hedayatollah , Moosavi-Movahedi Zainab
Published: August 2018

A nano vesicular was constructed with the complex consisting of hemin, imidazole Gemini and sodium dodecyl sulfate (SDS) in 50 mM phosphate buffer solution (PBS). The novel nano structure acted as an efficient artificial peroxidase (AP). The AP was also immobilized on a carboxyl functionalized multi-walled carbon nano-tubes (MWCNTs-COOH) and gold nano-particles (AuNPs) nano-complex modified glassy carbon (GC) electrode, with a formal potential of -31 ± 2 mV vs. Ag/AgCl in 50 mM PBS, at a scan rate of 0.05 Vs -1. The heterogeneous electron transfer constant (ks) was evaluated to be 5.4 ± 0.1s-1. The modified electrode can be used to detect hydrogen peroxide in the range from 0.03 to 160 μM linearly, with a detection limit of 0.03 μM. The apparent Michaelis-Menten constant (Kmapp) of AP modified electrode was evaluated to be 0.034 ± 0.003mM.
Effects on Nafion® 117 Membrane using Different Strong Acids in Various Concentrations
Authors: Napoli L. , Lavorante M.J. , Franco J. , Sanguinetti A. , Fasoli H.
Published: August 2018

The effects of the acid nature and its concentration on the physico chemical properties of the membranes were studied. How these parameters impact the performance of Nafion 117 as a polymer Electrolyte membrane is shown.In particular the effect of this membrane treatment on its properties was studied with the following five strong acids: -Nitric, Sulphuric, Perchloric, Phosphoric or Hydrochloric acid- in six different concentrations: -0.025 M, 0.05 M, 0.25 M, 0.5 M, 0.75 M and 1 M.It was found that the membrane shows a similar behaviour when it is treated with different strong acids, incorporating between 16 to 21 molecules of water depending on the concentration of the acid. The results show that the effect of the different concentrations on the membrane behaviour is remarkable. This leads to the conclusion that the best treatment is to use solutions 0.025 M and 0.05 M (twenty times more diluted than the most concentrated solution tested in the experience) of the strong acid.It was also shown that after the membrane hydration its size increases by 10 percent (average).
Synthesis and Performance of Sulfated Zirconia Catalyst in Esterification of Oleic Acid
Authors: Berrones R. , Camas K. , Pérez Y. , Ramírez E. , Pérez A. , Eapen D. , Sebastian P. J.
Published: August 2018

In this work, the performance of sulfated zirconia catalyst used in the synthesis of biodiesel by esterification of oleic acid was studied. For catalyst preparation the zirconium dioxide (ZrO) by Aldrich was used as precursor. The sulfated zirconia obtained was calcined for 3 hours at different temperatures (200, 400, 600 and 700 °C) in an oxygen atmosphere. Each of the calcination conditions generated a sample of catalyst, which was used in the esterification reaction. The esterification reaction was carried out using reagents such as oleic acid and methanol at a molar ratio 1:20. The sulfated zirconia catalyst was used in the reaction in various proportions by weightrelative to the weight of oleic acid (0.5, 1.0, 3.0 and 5%). The analysis of methyl ester conversion was performed by gas chromatography and mass spectrometry (CGMS) and the percentage area of the characteristic peaks as methyl oleate was quantified. A characterization of sulfated zirconia was also performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Finally, the catalyst performance was studied in the reduction of the acid index (AI) and the conversion of free fatty acids of oleic acid and compared to other commonly used catalyst for this purpose, which is concentrated sulfuric acid (H2SO4).
Carbon Supported Au-Pd-PdO with Low Metal Loading for Electro-oxidation of Methanol in Alkaline Medium
Authors: Ramos-Sánchez V-H , Brito-Picciotto Diana , Gómez-Vargas Ramón , Chávez-Flores David , Valenzuela Edgar
Published: August 2018

The present work examined two Pd-based alloys supported on carbon: AuPd and Au2Pd, both synthesized by chemical reduction with NaBH4. The low Au-Pd loading electrocatalysts were physicochemically and electrochemically characterized. Electrocatalytic activity for methanol oxidation was found exclusively in AuPd/C. However, it was revealed that such reaction was promoted by PdO occurring in the actual active phase of the supported electrocatalyst, through the formation of Au-Pd-PdO ensemble sites.
Investigations on the Effect of Chitin Nanofiber in PMMA Based Solid Polymer Electrolyte Systems
Authors: Shyly P. M. , Roy S. Dawn Dharma , Thiravetyan Paitip , Thanikaikarasan S. , Sebastian P. J. , Eapen D. , Shajan X. Sahaya
Published: August 2018

Polymer electrolyte membranes find application in a variety of fields such as battery systems, fuel cells, sensors and other electrochemical devices. In this paper we have done some investigations on the effect of chitin nanofiber (CNF) in PMMA based solid polymer electrolyte systems. CNF was synthesized from shrimp cell chitin by stepwise purification and acid hydrolysis method. PMMA basedelectrolyte films containing different concentrations of lithium salt and CNFs as filler were prepared by hot-press membrane technique. Crystalline nature and phase changes in polymer electrolytes were confirmed by X-ray diffraction analysis. Thermal behavior of the polymer electrolyte systems was studied by differential scanning calorimetry. Ionic conductivities of the electrolytes have been determined using a.c. impedance analysis in the temperature range between 303 and 393K. The temperature–dependent ionic conductivity
Studies on Electrodeposited NiS Thin Films
Authors: Bharathi B. , Thanikaikarasan S. , Chandrasekar P. V. , Kollu Pratap , Mahalingam T. , Ixtlilco Luis
Published: August 2018

Thin films of NiS have been deposited on indium doped tin oxide coated conducting glass substrates using electrodeposition technique. Structural studies revealed that the deposited films exhibit hexagonal structure with preferential orientation along (002) plane. Structural parameters such as crystallite size, strain and dislocation density are calculated for films with different thickness values obtained at various deposition time. The film composition and surface morphology have been analyzed using scanning electron microscopy and energy dispersive analysis by X-rays. Optical absorption analysis showed that the deposited films possess band gap value around 0.7 eV.
Preparation and Characterization of Ultraviolet-cured Polymer Electrolyte Poly(glycidyl methacrylate-co-methyl methacrylate)
Authors: Imperiyka M. , Ahmad A. , Hanifah S. A. , Rahman M. Y.A. , Mohamed N. S.
Published: August 2018

Effect of lithium triflate (LiTf) concentration on the properties of poly (glycidyl methacrylate-co-methyl methacrylate) P(GMAco-MMA)-based solid polymer electrolyte was investigated. The copolymer of (GMA-co-MMA) was synthesized by photopolymerization method. P(GMA–MMA) was fixed at the ratio of 90:10 based on the conductivity result of the electrolyte film. The electrolyte samples were characterized using impedance spectroscopy (EIS), cyclic voltammetry (CV) and thermogravimetric analysis (TGA). The room temperature conductivity was improved about six orders upon the addition of 30 wt. % LiTf salt into the polymer host. The highest room temperature conductivity was 1.4×10-6 S cm-1 at 30 wt. % LiTf. The highest conductivity of 1.25×10-4 S cm-1 was achieved at 393 K. The polymer electrolyte system exhibits Arrhenius-like behavior with the pre-exponential factor of 1.25×10-4 S cm-1 and activation energy of 0.39 eV. The electrolyte showed electrochemical stability window up to 3 V. The thermal stability increases with the salt concentration. The above results indicate that the electrolyte has potential for lithium ion battery application.
Polyvinyl Alcohol (PVA)-assisted Synthesis of BiFeO3 Nanoparticles for Photocatalytic Applications
Authors: Niu Feng , Gao Tong , Qin Laishun , Chen Zhi , Huang Qiaoli , Zhang Ning , Wang Sen , Sun Xingguo , Huang Yuexiang
Published: August 2018

Bismuth ferrite (BiFeO3) is a promising material for visible light response photocatalytic applications. In the present work, BiFeO3 particles were synthesized by a polyvinyl alcohol (PVA)-assisted solid state reaction processing. The XRD pattern result indicated that the as-prepared particles are pure BiFeO3 crystalline phase. The microscopy observation demonstrated that the BiFeO3 particle size is from 100 to 200 nm, which is smaller than that of the BiFeO3 prepared without addition of PVA. The HRTEM showed that BiFeO3 particle is polycrystalline and contains many small crystal grains with different orientations. Furthermore, such nanosized and well-dispersed BiFeO3 particles exhibited a much higher photocatalytic activity than the prepared BiFeO3 without addition of PVA for the photodegradation of methyl orange contaminant under visible light irradiation.
Electrolyte-Insulator-Semiconductor (EIS) with Gd2O3-based Sensing Membrane for pH-Sensing Applications
Authors: Wang Jiun-Jr , Lin Shang-Ren , Kao Chuan-Haur , Hu Ching-Hao , Chen Hsiang
Published: August 2018

Gd2O3 as pH sensing membrane on Si substrate treated with annealing for the electrolyte-insulator-semiconductor has been fabricated. The high-k sensing membrane can obtain high sensitivity, high linearity, low hysteresis voltage, and low drift rate. The high-k Gd2O3 pH sensing membrane show promise for future industrial sensing device applications.
Effects of Nano Carbon Conductive Additives on the Electrochemical Performance of LiCoO2 Cathode for Lithium Ion Batteries
Authors: Li Xinlu , Zhang Xinlin , Li Tongtao , Zhong Qineng , Yanyan Zhang Yanyan , Huang Jiamu
Published: August 2018

Carbon black(CB), multi-walled carbon nanotubes(CNTs) and graphene nanosheets(GNs) were employed as carbon conductive additives for LiCoO2(LCO). X-ray diffraction, transmission electron microscopy and scanning electron microscopy were used to characterize the crystal structure and morphology of samples. And the specific surface area and porosity structure of the three kinds of carbon conductive additives were measured by N2 adsorption-desorption. To investigate the effect on the electrochemical reaction activity, galvanostatic discharge-charge experiments showed that the composite of LCO-GNs exhibited the highest specific capacity of 167mAh/g at 0.1C and 123 mAh/g at 1 C rate. The flexible wrapping of GNs and bridging nearby LCO particles together were found to enhance electrical conductivity most effectively.
Synthesis and Properties of Electrochemically Deposited Vertical Mesoporous Silica Thin Films
Authors: Zhou Yuan , Liu Qiming , Feng Ye , Tan Min
Published: August 2018

Electrochemical deposition was successfully used to prepare mesoporous silica thin films with highly ordered and vertically oriented pores. Tetraethyl orthosilicate was used as the inorganic silicon source and cetyltrimethyl ammonium bromide was the template. A negative potential was applied to the working electrode, which was initially immersed in collosol and then in hydroxyl at the electrode/solution interface. Hydroxyl ion served as the catalyst that promoted the polycondensation and self-assembly of the silicon precursor, as well as the formation of thin films with pores which are highly ordered and vertically oriented with respect to the panel.The pore arrangement of the mesoporous film was hexagonal, and its aperture was 2 nm to 3 nm. The verticality of the thin film pore was demonstrated through permeability and transmission electron microscopy analyses. The prepared mesoporous film possessed good optical amorphous antireflective property with ordered and vertically oriented pores.
Zoufalství z vejšky
Authors: Dlouhá Jana
Published: August 2018

Reakce na to, co se děje v českém vysokém školství: plagiátorské kauzy ministrů nové české vlády, i „dopis statečného“ – zkušenost profesora Tomáše Grima, který se rozhodl systém předstírání vzdělanosti opustit.
3D Microstructure and Micromechanical Properties of Minerals in Vanadium-Titanium Sinter
Authors: Xu Runsheng , Wang Wei , Chen Weilin , Jia Bin , Xu Zhihui
Published: August 2018

To investigate the structural characteristics and mechanical properties of minerals in vanadium-titanium sinter, the 3D microstructures of the sinter were reconstructed by serial sectioning in conjunction with computer-aided 3D reconstruction techniques The results show that hematite and magnetite in vanadium-titanium sinter will grow along the longitudinal axis direction and act as a scaffold. The size of magnetite crystals in vanadium-titanium sinter is much smaller than that in traditional sinter. The calcium ferrite in vanadium-titanium sinter is columnar-like, while that in traditional sinter is needle-like. The decreasing order of the microhardness value of minerals in the two sinters is hematite, calcium ferrite, magnetite and silicate, while the fracture toughness value from highest to lowest is calcium ferrite, hematite, magnetite and silicate. The comprehensive hardness value and comprehensive fracture toughness value of vanadium-titanium sinter are both less than these of traditional sinter.
Asymmetries of null subjects and null objects in L1-English and L1-Japanese learners’ Chinese
Authors: Chang Hui , Zheng Lina
Published: August 2018

Based on the HSK Dynamic Composition Corpus, this study investigated the use of Chinese null arguments by advanced adult L1-English and L1-Japanese learners with Chinese native speakers as a baseline. Several asymmetries were found. First, the learners produced many more null subjects than null objects. Second, null subjects were mainly animate, while null objects were mainly inanimate. Third, more null subjects were used in non-matrix clauses than in matrix clauses. In addition, L1 did not seem to play a significant role in the learners’ use of Chinese null arguments, and the learners’ use Chinese null arguments was generally not native-like. Finally, it appears that null objects are not transferable or developmental and that infrequent use of null objects is universal in L2. It was argued that positive evidence in the target input as well as the nature of the subject and the object led to the asymmetric use of null subjects and null objects in L2 Chinese.
Internet-Memes als Zugang zu multimodalen Konstruktionen
Authors: Bülow Lars , Merten Marie-Luis , Johann Michael
Published: August 2018

The adaptation of Internet memes is an important practice in social media that is an excellent subject of investigation to explain (the instantiation of) multimodal constructions with regard to social-cognitive processes. In this article, we would like to plead for paying more attention to Internet memes as linguistic research object. By using a qualitative-quantitative corpus-pragmatic approach, we worked out the multimodal character of selected constructions being instantiated within adaptations of the so called Merkel-Meme (n=632). We discuss two constructions, which can only be thought of through the interplay of a pictorial component that shows a gesture and varying linguistic elements. This is on the one hand the construction [[so*adjektiv]AdjP+ Ausprägungsgrad anzeigende Armgeste] and on the other the construction [[so*artikel(adjektiv)nomen]NP+ Umfang anzeigende Armgeste]. Therefore, it becomes evident that the pictorial component influences the linguistic part of the Internet meme.
Evaluation Method of Resistance to Water Damage for Foamed Warm-Mixed Asphalt Mixture Based on Surface Free Energy Theory
Authors: Wei Wuju , Zheng Bingfeng , Han Chao , Niu Xiaowei , Xu Jinyu , Yan Jinhai
Published: August 2018

Weak adhesion between asphalt and aggregates is the main cause of moisture-induced damage for asphalt pavement, especially for foamed warm-mixed asphalt pavement, because of low mix temperatures and residual moisture left behind by the microscopic foaming process. In order to improve the road performance of foamed warm-mixed asphalt mixture, the law of moisture evaporation of foamed asphalt was discussed through laboratory foaming test in this article. The surface free energy of foamed asphalt in different foaming stages and two kinds of aggregates were obtained by measuring contact angle via the sessile drop method. The work of cohesion and adhesion between asphalt and aggregates and the work of stripping were calculated through using their surface free energy parameters. On this basis, the energy ratio (ER) is proposed as an indicator to evaluate the anti-water damage property of foamed warm-mixed asphalt mixture, and the ER is obtained by calculating the ratio of work of adhesion and the work of stripping. This method can be used as the reference for the evaluation of asphalt adhesion. The results may show that the resistance to moisture-induced damage of asphalt is improved after foaming process.
Measuring Nonequibiaxial Residual Stresses and Mechanical Properties Using Knoop Indentation
Authors: Hosseinzadeh A. R. , Mahmoudi A. H.
Published: August 2018

A proper knowledge of the mechanical properties and residual stresses of materials has a significant role in the prediction of engineering failures. Indentation is a simple, nondestructive test that is capable of estimating both residual stresses and mechanical properties. In frequent studies, the response of materials during the indentation process has been used as a key parameter to distinguish different substances. Here, a state-of-the-art method with no undesirable restriction is suggested to attain the work hardening exponent, yield strength, and planar nonequibiaxial residual stresses. In the current work, an extensive series of Knoop indentation simulations were performed using two indenter angles. Subsequently, a precise observation was made in order to find existent relationships. A local method was employed based on characteristics of similar materials to obtain stress-free sample parameters through a genetic algorithm, and then another error function was defined in order to measure the yield strength and work hardening exponent. After the determination of the mechanical properties and the stress-free sample’s parameters, a particular and precise categorization was made. Then, neural network analysis was employed to derive planar residual stresses. Experimental validation was conducted using six types of aluminum and steel specimens. The results confirmed a good agreement between the test data and those predicted using the suggested procedure.
The Shear Strength of the Nature Loess Joint: A Case Study in Shaanxi Province
Authors: Liu Xiaojun , Zheng Xing , Cheng Wen-Chieh , Kong Qing , Wang Juanjuan
Published: August 2018

Shear strength of the loess joint has significant influence on the stability of loess engineering with joints. “Joint” is the weak structural plane of loess, and its shear strength determines the stability of loess. In this study, a series of loess joint samples was collected from Binxian County, Liquan County, and Zichang County in Shaanxi Province. The shear strength of the loess joint was determined by means of the direct shear test. The influence of the water content on the shear strength parameters of the loess joint was investigated by means of tests. The results showed that initially the internal friction angle varied slightly with the water content but decreased very quickly as the water content surpassed the threshold value of 14 %. The relationship between shear strength and water content can be expressed as an exponential function. This study devised a new empirical formula that determines the peak internal friction angle by observing the effects of dry density, water content, shear strength, and joint surface morphology.
A Novel Approach for Analytical Description of the Isothermal Bainite Transformation in Alloyed Steels
Authors: Maisuradze M. V. , Yudin Y. V. , Kuklina A. A.
Published: August 2018

A novel approach for modeling the bainite transformation in alloyed steels during isothermal quenching is presented. The approach is based on the application of the logistic function with the logarithmic argument of the isothermal holding time. The proposed model involves two time-independent fitting parameters, a and b, where are specified for the given isothermal quenching temperature and other conditions (e.g., steel grade, austenite grain size, etc.). The adequacy of the modeling results is estimated using the sum of squared differences between the experimental and calculated bainite fraction formed at every time step Δτ during isothermal quenching. The logistic function was found to provide a fit between the experimental and calculated bainite transformation kinetics that was up to ten times better than that of the conventionally applied Kolmogorov–Johnson–Mehl–Avrami equation. An excellent agreement is achieved between the modeling results and the experimental data for commercially produced high-strength alloyed steels 300M, HY-TUF, and D6AC isothermally quenched in the temperature range of the bainite transformation. The obtained temperature dependences of the model parameters a and b reveal the potential for further theoretical investigation and verification of their physical meaning.
Cultura ciudadana para la resolución pacífica de conflictos saberes y prácticas que la fortalecen
Authors: Martínez Romero Emma Lucía
Published: August 2018

El artículo da cuenta de la sistematización de la iniciativa Cátedra de paz implementada en la Institución Educativa Técnica Agropecuaria de Desarrollo Rural (IETAD) la cual nace en un contexto que afronta problemas producto de las secuelas de la guerra esmeraldera y de narcotráfico en el occidente de Boyacá. Los objetivos apuntaron a determinar cuáles eran los saberes y las prácticas pedagógicas que permiten fortalecer la cultura ciudadana para la resolución pacífica de conflictos.Metodológicamente se desarrolló el enfoque cualitativo por medio del diseño de sistematización de experiencias dando reconocimiento a docentes, padres y estudiantes y sus prácticas mediante el empleo de la entrevista semiestructurada y la cartografía social pedagógica.Como resultados se abordaron tres líneas. A) Contextos cultura ciudadana fragmentada debido a la cultura de ilegalidad, la justicia por mano propia, aumento de familias en ambientes disfuncionales. B) Saberes: transcendencia y reconocimiento de las normas, valores, el debido proceso y concepciones sociales. C) Prácticas: contrastan el buen ejemplo vs ambientes disfuncionales, sanción, estrategias pedagógicas. A nivel de conclusiones como antípodas de la violencia se destacaron: el juicio moral, el reconocimiento y la resignificación de la cultura campesina; Las emociones evidenciaron fracturas pero también formas de potenciar la lucha por la reivindicación y garantía de los derechos, la relevancia del cuidado y su proyección.La mirada desde el contexto y su praxis genera reflexión y la posibilidad de encaminar acciones que aporten a la dignidad y la construcción del tejido social en especial en la transición al postconflicto.
EVALUACIÓN DE LAS ASOCIACIONES DE PECES DE LOS ARRECIFES CORALINOS DEL CENTRO INTERNACIONAL DE BUCEO MARÍA LA GORDA, PARQUE NACIONAL GUANAHACABIBES, CUBA.
Authors: Cobián Rojas Dorka , Chevalier Monteagudo Pedro Pablo
Published: August 2018

El buceo contemplativo en los arrecifes coralinos es una de las pocas actividades autorizadas en el área manejada por el Centro Internacional de Buceo María la Gorda del Parque Nacional Guanahacabibes. Se evaluó la composición y estructura de las asociaciones de peces en los arrecifes utilizados por el Centro Internacional de Buceo María la Gorda. Considerando la posibilidad de cambios estacionales en la densidad y composición de los peces, se realizaron muestreos en las épocas seca y lluviosa. Se realizaron censos visuales en ocho sitios de buceo (12 transectos de 50 x 2 m en cada uno), en dos biotopos característicos del arrecife. Se estimaron los índices de diversidad, equitatividad, riqueza de especies, densidad y biomasa de peces. Los valores de densidad  promedio y los índices de diversidad por estaciones no mostraron diferencias significativas entre las épocas. Se registraron 134 especies en toda el área. La abundancia de peces fue superior en los sitios de mayor complejidad estructural, correspondientes a la zona de camellones de la pendiente arrecifal. Se observó un predominio de peces de pequeña talla y pobre presencia de peces de mediana y gran talla. Las familias con mayor densidad fueron Pomacentridae y Labridae, y las de mayor biomasa Lutjanidae y Labridae. La estructura trófica estuvo dominada por los plantófagos y omnívoros. Aunque se observaron carnívoros de tallas medianas, su densidad fue inferior al resto de los grupos, lo cual parece ser consecuencia de la pesca furtiva.Recreational SCUBA diving on the coral reefs is one of the few activities allowed in the area managed by the Centro Internacional de Buceo María la Gorda at the Guanahacabibes National Park. The composition and structure of fish associations were evaluated on the reefs visited by users of the diving center. To assess possible seasonal changes in fish community densities and composition surveys were carried during the dry and rainy seasons. Visual censuses were carried out at eight diving sites comprising two characteristic reef biotopes. Indices for diversity, evenness, species richness, density, and fish biomass were estimated. Mean density values by sampling site did not show significant differences between seasons. A total of 134 species were recorded in the area. Fish abundances were greater in sites of higher structural complexity, matching areas of ridges on the reef slope. Prevalence of small-sized fish and a general poor presence of medium to high-sized fish were observed. Fish families with the higher densities were Pomacentridae and Labridae, and those with the higher biomass were Lutjanidae and Labridae. The trophic structure was dominated by phytophagous and omnivorous fish. Medium-sized carnivorous fish were observed, however, their densities were much lower than for the rest of the trophic groups, which could be a consequence of illegal fishing activities.
Skaitmeninės atskirties požymiai ir lygmenys: Lietuvos atvejo analizė
Authors: Šuminas Andrius , Gudinavičius Arūnas , Aleksandravičius Arnas
Published: August 2018

[only abstract and keywords in English; full article, abstract and keywords in Lithuanian]

After the sudden growth of popularity of IT and the internet, scholars have noticed emerging differences between usage or non-usage of the internet among different individuals and groups of society. These differences were defined as the digital divide. At first, more attention was given to the differences of access to IT and the internet, but today, scholars are focusing on another level of the digital divide – one determined by skills, perceived value and motivation. In this article, we examine the characteristics of the different levels of the digital divide by analyzing various statistical indicators. We seek to explain which groups of Lithuanian society feel the social and digital divide the most; also, we explain the features and changes of every level of the digital divide.
Politinio lyderio retorika: nuo senovinės agoros iki elektroninės demokratijos
Authors: Vaičekauskienė Giedrė
Published: August 2018

[only abstract and keywords in English; full article, abstract and keywords in Lithuanian]

This article analyzes political leadership that uses rhetoric as one of the means to influence the electorate. Rhetoric denotes negotiatory communication between different individuals aimed at reaching a general agreement. This theoretical discourse reflects on the characteristics of classical rhetoric, established in the practice of citizenship of the Athenian Democracy, appealing to its return and identifying a new era of political communication – the characteristics of electronic democracy, which powerfully transforms the language and relations of the elected and representatives of the society. In a modern virtual agora, the political leader directly informs his electorate, and the internet provides the leader with a wide range of communication tools to influence the voter. The new media creates a new policy and a new political language, which becomes an object worthy of the researchers’ interest. The electronic agora is full of communicative noise, with the prevalence of a fragmentary, scattered, tag cloud rhetoric.The aim of this article is to reveal the issues of reliability of the rhetoric of the modern political leader from the perspective of political leadership constructed on the internet.
Child Passenger Safety
Authors: Durbin Dennis R. , Hoffman Benjamin D. ,   COUNCIL ON INJURY, VIOLENCE, AND POISON PREVENTION, Agran Phyllis F. , Denny Sarah A. , Hirsh Michael , Johnston Brian , Lee Lois K. , Monroe Kathy , Schaechter Judy , Tenenbein Milton , Zonfrillo Mark R. , Quinlan Kyran
Published: August 2018

Child passenger safety has dramatically evolved over the past decade; however, motor vehicle crashes continue to be the leading cause of death for children 4 years and older. This policy statement provides 4 evidence-based recommendations for best practices in the choice of a child restraint system to optimize safety in passenger vehicles for children from birth through adolescence: (1) rear-facing car safety seats as long as possible; (2) forward-facing car safety seats from the time they outgrow rear-facing seats for most children through at least 4 years of age; (3) belt-positioning booster seats from the time they outgrow forward-facing seats for most children through at least 8 years of age; and (4) lap and shoulder seat belts for all who have outgrown booster seats. In addition, a fifth evidence-based recommendation is for all children younger than 13 years to ride in the rear seats of vehicles. It is important to note that every transition is associated with some decrease in protection; therefore, parents should be encouraged to delay these transitions for as long as possible. These recommendations are presented in the form of an algorithm that is intended to facilitate implementation of the recommendations by pediatricians to their patients and families and should cover most situations that pediatricians will encounter in practice. The American Academy of Pediatrics urges all pediatricians to know and promote these recommendations as part of child passenger safety anticipatory guidance at every health supervision visit.
Deformations of Noncompact Calabi-Yau threefolds
Authors: Gasparim Elizabeth , Köppe Thomas , Rubilar Francisco , Suzuki Bruno
Published: August 2018

Describimos deformaciones de 3-variedades Calabi-Yau no compactasWk := Tot(OP1 (-k) ⊕ OP1 (k - 2)),para k = 1, 2, 3. Concretamente, calculamos las deformaciones a través del primer grupo de cohomología H1(Wk, TWk) vía cohomología de Čech. Mostramos que para cada k = 1, 2, 3 las estructuras asociadas son cualitativamente distintas y, además, comentamos sobre sus diferencias con las estructuras análogas de las 2-variedades no compactas Tot(OP1 (-k)).
THE EFFICIENCY OF RICE HUSK BIOCHAR APPLICATION TO GROW BRASSICA JUNCEA (Brassica juncea (L.) Czern.) IN THE EXPERIMENTAL POTS OF LOAMY SAND SOIL
Authors: Tu Tran Thi
Published: August 2018

Biochar was produced from rice husk at temperature from 276 to 760 oC. The objective of the study was to determine the influence of the biochar application to loamy sand soil on crop growth and nutrient balances under greenhouse conditions in Hue city. Loamy sand soil was collected in Huong Chu commune, Huong Tra town. Pot experiments with Brassica juncea (Brassica juncea (L.) Czern.) were conducted in three different types of biochar quantity into soil such as 15 g/pot (765 g/m2), 30 g/pot (1531 g/m2) and 60 g/pot (3062 g/m2). Chemical fertilizer was applied to the soil at rates of 12.2÷ 24.5 g N/m2, 10.3÷ 20.6 g P2O5/m2 and 12.0 ÷ 24.0 g K2O/m2. Experimental results showed that biochar application changed soil quality, resulted in improving the growth of Brassica juncea. We will report the difference of nitrogen and phosphorus balances (crop uptake, leaching, retention, etc.) in experimental pots. Our results indicated that the use of biochar from agricultural by-products would be beneficial for farmers, the environment under soil and climatic conditions in Thua Thien Hue province.
STUDY OF COPPER REMOVAL IN WATER BY ION EXCHANGE MATERIAL
Authors: Thanh Hai Pham Thi
Published: August 2018

In this study, sulfonation of polystyrene waste was investigated of the possibility of the removing Cu (II) ions in solution. Fourier transform infrared (FTIR) of sulfonation polystyrene waste was performed to study the material characteristics and the results showed the presence of sulfonic group bands. The efficiency of Cu (II) ion removal in ion exchange column experiments indicated that the quality of sulfonation of polystyrene waste depended on some factors as the reaction time, height of the column and the velocity of the flow rate. Ion exchange experiments were carried out with the columns of 8 and 6 mm internal diameter, of which 10 cm of column bed height in the 8 mm-diameter column obtained the highest efficiency of 74.13 % at 1 hr reaction time, and flow rate of 1.48 mL per min. The experimental data were consistent with Thomas and Yoon-Nelson kinetic models.
ANALYSIS OF WASTE FLOWS USING WIO TABLE
Authors: Anh Tuyet Nguyen Thi
Published: August 2018

As industrial sectors and waste management sectors are related to each other in IO table, this paper aims to inventory waste cycles among the sectors in Vietnam using IO (Input – Output) table and WIO (Waste Input - Output) model. The national published data of 164 product sectors are based on the 2012 IO table updated for 2016. The material flows that each sector contributes to the others are quantified and then combined with the corresponding waste generation coefficient to determine the load of waste generated, collected and treated for each sector. The investigated data include quantity and composition of hazardous and solid waste handled by 200 waste treatment facilities in 2016. The type of waste is limited to 3 categories including wastewater, domestic and normal industrial waste, and hazardous waste. The research drives towards to build an economic mathematical model for Vietnam that gives a quantified analysis of waste flows.
Cigarette Smoke and E-Cigarette Vapor Dysregulate Osteoblast Interaction With Titanium Dental Implant Surface
Authors: Rouabhia Mahmoud , Alanazi Humidah , Park Hyun Jin , Gonçalves Reginaldo Bruno
Published: August 2018

The purpose of this study was to determine the possible deleterious effects of e-cigarette vapor on osteoblast interaction with dental implant material. Osteoblasts were cultured onto Ti6Al4V titanium implant disks and were then exposed or not to whole cigarette smoke (CS), as well as to nicotine-rich (NR) or nicotine-free (NF) e-vapor for 15 or 30 minutes once a day for 1, 2, or 3 days, after which time various analyses were performed. Osteoblast growth on the titanium implant disks was found to be significantly (P < .001) reduced following exposure to CS and to the NR and NF e-vapors. Osteoblast attachment to the dental implant material was also dysregulated by CS and the NR and NF e-vapors through a decreased production of adhesion proteins such as F-actin. The effects of CS and e-cigarette vapor on osteoblast growth and attachment were confirmed by reduced alkaline phosphatase (ALP) activity and tissue mineralization. The adverse effects of CS and the NR and NF e-vapors on osteoblast interaction with dental implant material also involved the caspase-3 pathway, as the caspase-3 protein level increased following exposure of the osteoblasts to CS or e-vapor. It should be noted that the adverse effects of CS on osteoblast growth, attachment, ALP, and mineralized degradation were greater than those of the NR and NF e-vapors, although the latter did downregulate osteoblast interaction with the dental implant material. Overall results suggest the need to consider e-cigarettes as a possible contributor to dental implant failure and/or complications.
Major Bifurcations, Slip Rates, and A Creeping Segment of Sumatran Fault Zone in Tarutung-Sarulla-Sipirok-Padangsidempuan, Central Sumatra, Indonesia
Authors: Natawidjaja Danny Hilman
Published: August 2018

DOI: 10.17014/ijog.5.2.137-160A detailed active fault study in Tarutung-Sarulla-Sipirok-Padangsidempuan was conducted based on their tectonic-morphological features using SRTM-30, 3D-visualization, and LIDAR data, combined with field and shallow geophysical surveys using the GPR method. Sumatran Fault Zone is bifurcated from the single major Sianok fault segment into two major branches: Angkola and Barumun-Toru Faults that run (sub) parallel to each other. In the studied area, they are merged gradually to become the Renun Fault. The total slip rates from Sianok to Renun segments are constant at about ~ 14 mm/year (13.8 ± 0.3 mm/yr on Renun and 13.7 ± 1.6 mm/yr on Sianok segments). In the bifurcation zone, it is partitioned into 9.3 ± 1.8 mm/yr slip on Toru, and about 4 - 5 mm/yr on Angkola segments. Based on field evidence supported by the seismicity and historical record, the Toru Fault appears to move continuously (creeping). This is crucial for understanding tectonics and its significance to hazard mitigations. Further investigations on Angkola and Toru Faults are crucial for mega installations of Sarulla Geothermal Power Plant, which is located in between Angkola and Toru Fault zones.
The Russian Law Journal as a Challenge for Russia’s Legal Academia – A Few Remarks by the Chief Editor on the 5th Anniversary of the Journal
Authors: Maleshin Dmitry
Published: August 2018

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