bluuebunny/crossref_metadata_2025 huggingface dataset:
Lecciones de ilusión: una introducción al estudio de la narrativa insólita de Pablo d’Ors
Authors: Fernández Sánchez-Alarcos Raúl
Published: June 2021

Se analiza Lecciones de ilusión destacando su singularidad dentro del panorama de la novela española actual, situándose la novela de d’Ors dentro de la tradición de la novela moderna centro-europea (Kafka, Mann, Kundera, etc.). Este trabajo tiene por objeto estudiar el tipo de representación de la realidad y de la existencia que se da en la novela. Descubriremos que la originalidad de d’Ors estriba en que, pese a situarse en la tradición de una novelística definida por su visión pesimista y desarraigada, utiliza, sin embargo, procedimientos narrativos modernistas para proponer finalmente una visión positiva y luminosa de la experiencia humana. Novela en la que, en definitiva, los planos de la realidad, la fantasía y la ficción se confunden para poner de relieve la condición ontológica y hermenéutica del ser humano: ser límite fronterizo del mundo.
La influencia de la actividad física de los padres en la participación deportiva. ¿Cómo afecta a la desigualdad de clase social?
Authors: Muñoz-Comet Jacobo , Martínez-Pastor Juan-Ignacio
Published: June 2021

Este artículo explora cómo la actividad deportiva de los padres modera el efecto de la clase social en la participación deportiva de los individuos. A partir de las cuatro Encuestas de Hábitos Deportivos en España realizadas por el CIS, los resultados confirman que pertenecer a una clase social más alta y tener padres físicamente activos (tanto en el presente como en el pasado) aumenta la probabilidad de hacer deporte. Sin embargo, los análisis revelan que el efecto positivo de tener padres que practican deporte en la actualidad es, en igualdad de condiciones, más fuerte para las clases sociales que no están en la parte superior de la estructura social. Estos hallazgos muestran el efecto igualador de tener padres activos, de tal modo que las diferencias entre la clase profesional y el resto desaparecen, o incluso se invierten, cuando se trata de practicar deporte al menos tres veces por semana.
La confusión populista: problemas conceptuales y sesgos ideológicos
Authors: Sola Jorge
Published: June 2021

Esta nota bibliográfica ofrece una revisión crítica de tres contribuciones recientes al estudio del populismo: ¿Qué es el populismo? de J. W. Müller, La explosión populista de J. B. Judis y Populismo: una breve introducción de C. Mudde y C. Rovira Kaltwasser. Los tres trabajos parten de perspectivas parcialmente divergentes, por lo que proporcionan una panorámica apropiada para su discusión conjunta en torno a los problemas conceptuales y los sesgos ideológicos que acompañan al uso del término ‘populismo’. En la nota se defiende que, de cara a esquivar estos problemas, es más apropiado entender el populismo como un simple marco discursivo, en lugar de como una ideología que representa un peligro para la democracia liberal.
La burocratización neoliberal de la participación ciudadana en España
Authors: Martínez-Palacios Jone
Published: June 2021

Ante el giro participativo global que se registra en las denominadas democracias occidentales, este artículo tiene por objetivo conocer la forma particular que adopta dicho giro en España. Para ello, se realiza un análisis desde un punto de vista genético de la institucionalización de la participación ciudadana en el país entre los años 1978 y 2017. De dicho análisis se concluye la existencia de una tendencia neoliberal con la que se implementa el giro participativo. En el texto se esbozan los tres movimientos principales que componen el diagnóstico de giro participativo neoliberal: 1) La naturalización de topos de la crisis de la democracia de carácter mecanicista; 2) la burocratización neoliberal de la participación y 3) la mercantilización privativa de la participación. Se explican las líneas generales de los tres movimientos y se profundiza en el análisis particular del segundo de ellos, la burocratización neoliberal de la participación ciudadana.
El hornabeque de Saint-Jean, en Soissons : vestigios arqueológicos e intento de contextualización histórica [artículo resumido]
Authors: Buccio Vincent
Published: June 2021

La excavación parcial de una obra avanzada de la fortificación urbana de Soissons (Aisne), construida y desmantelada durante el siglo xix, ha permitido contrastar la abundante documentación archivística referente a esta construcción con las observaciones sobre el terreno. La arqueología permite comprobar la fiabilidad de las fuentes escritas y sacar a la luz los componentes de la historia de la fortificación que no están descritos en los textos. De este modo, el presente estudio permite seguir la evolución de una obra de arquitectura desde el anteproyecto hasta su desmantelamiento, pasando por su construcción y las vicisitudes en su funcionamiento. Al final de este estudio, se evalúa la pertinencia de excavar una estructura reciente, pese a la existencia de un elevado número de documentos de archivo.
De la trace au patrimoine. Archéologie de la mise en mémoire d’un quartier autoconstruit à Marseille
Authors: Basset Karine
Published: June 2021

L’ensemble d’habitation autoconstruit dit Chieusse-Pasteur, dans le XVIe arrondissement de Marseille, a connu depuis l’annonce des premières intentions de sa « réhabilitation », au début des années 1980, une trajectoire de patrimonialisation originale. Elle aboutit en 2015, vingt ans après la destruction de cet ensemble, à l’entrée d’un objet-trace, une maquette partielle du quartier, au Musée d’histoire de la ville. L’archéologie de la « mise en mémoire » de Chieusse-Pasteur permet de comprendre comment et par qui fut construite la singularité de cet héritage urbain, et les sens qui lui furent conférés. Au centre de cette trajectoire, la maquette de l’îlot disparu circule entre différents espaces mémoriels, fait émerger un débat sur le statut de la trace et questionne la nature et la portée des récits qu’elle suscite. Dans quelle mesure l’entrée au musée permet-elle aux anciens habitants d’un lieu disqualifié de faire pleinement valoir leur droit à « habiter le temps » de la ville ?
Effect of In Situ TiB2 Particles on the Grain Size and Mechanical Properties of 7075 Aluminum Alloy
Authors: Ma Shao Ming , Wang Chuan Liu , Fan Yun Lin
Published: June 2021

Light-weight and high-strength aluminum alloy drill pipes are potential and promising to replace traditional steel drill pipes. In this study, the grain size and mechanical properties of aluminum alloy drilling pipe materials reinforced by in-situ TiB2 particles were studied. The results showed when reinforced by in-situ TiB2 particles the grain size of aluminum alloy materials was refined from 155 m to 57 m and ultimate tensile strength was increased from 590 MPa to 720 MPa. Besides, the results also indicated that the friction coefficient was reduced from 0.99 to 0.50 and thus the abrasion resistance of 7075 aluminum alloy was enhanced by 34 %. This study provided theoretical basis for the application of light-weight and high-strength aluminum alloy drill pipes in directional drilling and ultra-deep wells.
Preparation of Magnetic Alginate-Based Biogel Composite Cross-Linked by Calcium Ions and its Super Efficient Adsorption for Direct Dyes
Authors: Li Bei Gang , Lin Wen Jie
Published: June 2021

Magnetic sodium alginate (SA)-based biosorbent Fe₃O₄@SA-Ca gel beads were synthesized by droplet polymerization using Ca2+ ions as crosslinking agent, and characterized by Scanning Electron Microscopy (SEM). Fe₃O₄@SA-Ca polymer was used for the removal of Direct Orange 26 (DO-26) dye from water. The ratio of raw materials and some important conditions affecting the adsorbent performance were carefully examined. The adsorption kinetics, isotherms and thermodynamics were investigated. When the concentrations of SA, CaCl2 and Fe3O4 solutions were 1.9, 10 and 10 g/L, respectively, the black Fe₃O₄@SA-Ca gel beads with about 3 mm diameter were successfully prepared by curing 6h at room temperature. The polymer gel exhibits ultra-high adsorption capacity of 1252 mg/g and removal efficiency of 96.2 % for DO-26 under the conditions of 0.05 g polymer dosage, 2600 mg/L of dye initial concentration, solution pH 2.0 and 90 min of the adsorption time at 298 K. The dye removal efficiency can be all over 92 % in a wide pH range of 2.0 to 10.0. The adsorption process completely accorded with the pseudo-second-order rate model at different temperatures (298 ~ 328 K). The dye adsorption behavior was well in line with Freundlich model. The thermodynamic study indicated that the adsorption reaction was of spontaneous and exothermic nature. SEM analysis showed that the Fe₃O₄@SA-Ca gel beads appeared uneven surface with irregular folds and grooves. A high-cost-effective magnetic biosorbent, Fe₃O₄@SA-Ca can super effectively remove direct dyes from high-concentration wastewater in a wide range of acidity, and can be easily separated and recovered from water after adsorption without secondary pollution, and would have a good application prospect.
Effect of Particle Size and Shape on Flowability of FGH96 Superalloy Powder
Authors: Zhang Li Chong , Xu Wen Yong , Li Zhou , Zheng Liang , Liu Yu Feng , Zhang Guo Qing
Published: June 2021

The effect of particle size and shape on flowability of FGH96 superalloy powder was investigated by field emission scanning electron microscopy (FE-SEM), laser particle size analyzer (LPSA) and X-ray photoelectron spectroscopy (XPS). The results showed that the powder flowability basically presented a decreasing trend as the median diameter decreased. The Hall velocity of the five median diameter powders (50=203.9 μm, 106.3 μm, 83.2 μm, 73.8 μm, 19.9 μm) was 27.18 s/50g, 23.25 s/50g, 23.86 s/50g, 23.42 s/50g and none, respectively. The surface oxides/ hydroxide/nitride of the five median diameter powders were mostly the same, mainly including Al2O3, Cr2O3, MoO3, Nb2O5, Ni (OH)2, TiO2 and TiN. The median diameter 50, shape factors (circularity, aspect ratio, roundness, solidity) and fractal dimension were selected to quantitatively characterize particle size and shape. For the same fluctuation value of powder flowability, the roundness and solidity showed lower sensitivity. Compared with the two shape factors, the sensitivity of circularity and aspect ratio was at an intermediate level, while the median diameter and fractal dimension displayed higher sensitivity. The median diameter and fractal dimension can be used to characterize the principal variation of flowability. The circularity and aspect ratio can be utilized to characterize the variation of flowability supplementally.
Effect of Cryogenic Treatment on the Microstructure and Mechanical Properties of Extruded Mg-3.5Zn-0.6Gd Alloy
Authors: Zhang Qing Hao , Luo Lan , Liu Yong , Xu Zi Hui
Published: June 2021

The effect of cryogenic treatment (CT) on the microstructure and mechanical properties of the as-extruded Mg–3.5Zn–0.6Gd alloy was investigated. The results showed that W-phase newly appeared in cryogenic treatment samples but without notable second phase amount increasing. There was also no remarkable grain refinement. But the amount of twins reduced greatly, the strong basal texture {0001} rotated and increased. The intensity of plane (0002) diffraction peak was weakened along with planes ( 1 0-1 0 ) ( 1 0-1 1 ) being enhanced in X-ray diffraction pattern. The change in mechanical properties was not obvious. The mechanism of the microstructure evolution is discussed as well.
Preparation of Sub-Micron Bi Alloy Powers with the Ultrasonic Mixed Crushing
Authors: Zhang Qiao Xia , Shi Jing Tao
Published: June 2021

The powders of the BiInSn alloy were produced by the ultrasonic atomization and the ultrasonic mixed crushing using the different dispersants. In this study, the composition, microstructure, melting point, and size of these powders were observed. The viscosity of different solutions of the dispersants and the mechanical properties of the sintered bulk materials were also tested. From the data analysis and results, we found that the composition of the powders using the different methods was consistent with the as-cast state. In addition, the size of powder produced by ultrasonic mixed crushing was significantly smaller than that ultrasonic atomization. And during the ultrasonic crushing process, with the increase of the viscosity of the dispersant, the size of the final powder also decreased, and even submicron powder were produced. The product of submicron powder could effectively improve the density and mechanical properties of sintered materials. And the principles of ultrasonic atomization and ultrasonic mixed crushing were discussed. We found that the mechanism of ultrasonic mixed crushing to produce powder was the micro-shock-wave theory of ultrasonic cavitation. At the same time, these dispersants were effective in keeping the droplets separate from each other and preventing them from merging back into the larger droplets. The droplet was solidified into a powder by rapid cooling in the end.
Effect of Pulse Current on Mechanical Behavior of High Temperature Titanium Alloy Ti55
Authors: Wan Hai Feng , Xu Ai Jun , Huang Yun Long , Tang Ze Jun
Published: June 2021

The effects of pulse current on the tensile properties of high temperature titanium alloy Ti55 were investigated by pulse current assisted uniaxial tensile test under different electrical parameters. It was found that with the increase of peak current and pulse width, the tensile properties of Ti55 are significantly improved. At the same time, the pulsation effect of current on the mechanical properties of Ti55 was investigated. The results show that the tensile displacement of low pulsation group was higher, while the elongation of high pulsation group was higher. In order to explore the mechanism of pulsation effect of current, EBSD was adopted. The results indicated that high pulse current can significantly promote the dislocation movement and recrystallization. In addition, some macrozones was found in low pulsation group, which indicated that high pulsation current was more suitable for material forming than low pulsation current.
Microstructure Evolution and Mechanical Properties of Mg-10.37Gd-3.66Y-2.27Zn-0.52Zr Alloy during Reciprocating Upsetting-Extrusion
Authors: Wu Guo Qin , Yu Jian Min , Jia Lei Chen , Xu Wen Long , Tian Yong Gang , Zhang Zhi Min
Published: June 2021

The homogenized Mg-10.37Gd-3.66Y-2.27Zn-0.52Zr alloy was subjected to multi-passes reciprocating upsetting extrusion (RUE) deformation with variable temperature. The microstructure evolution and mechanical properties of as-homogenized and RUEed samples were investigated. The results showed that the area fraction of DRX grains gradually increased via the continuous consumption of coarse grains containing lamellar LPSO, and the content of the bulk LPSO phases gradually decreased due to continuous fragmentation. After three passes deformation, the microstructure was almost composed of completely DRXed grains. The LPSO phases with different morphologies were coordinated deformation by kinking, tearing, etc during RUE process. It is worth noting that after four passes, the lamellar LPSO phase did not disappear, but mixed with the fine DRXed grains together. In addition, a mass of particles were produced after each low temperature deformation, indicating that reducing the deformation temperature is beneficial to the dynamic precipitation. The yield tensile strength (TYS), Ultimate tensile strength (UTS) and fracture elongation (FE) of four passes deformed alloy reached 372.6 MPa, 320.8 MPa, 8.1%, respectively. The improvement of mechanical properties is attributed to the two main strengthening mechanisms: grain refinement and LPSO strengthening.
Effect of Heat Treatment on Microstructure and Mechanical Properties of AlSi10Mg Alloy Fabricated by Selective Laser Melting
Authors: Qi Peng , Li Bo Long , Wang Tong Bo , Zhou Lian , Nie Zuo Ren
Published: June 2021

The effects of the heat treatment process parameters on the microstructure and mechanical properties of a selective laser melted (SLMed) AlSi10Mg alloy were systematically investigated. The SLMed AlSi10Mg alloy was treated with T1 (180°C× 4h + air cooling) process, which had the microstructure of fine α-Al grains, fine Si phase, and nano-sized precipitations. The microhardness significantly increased to 150 HV, which is even higher than as-SLMed one (126 HV). The microhardness of SLMed AlSi10Mg alloy treated with T4 (540°C × 2h + water cooling) heat-treatment process significantly decreased to 62 HV due to the growth of α-Al grains, Si phase and the formation of β-AlFeSi phase. However, the microhardness and ultimate tensile strength of AlSi10Mg alloy treated with T6 (540°C × 2 h water cool + 180°C × 4 h air cool) process decreased to 91 HV, although the strengthening precipitation of Mg2Si phase formed. It indicates that the Mg2Si phase cannot compensate for the adverse effect of grain growth. It may provide the best potential heat treatment method for fabricating the high strength SLMed AlSi10Mg alloy.
Spinning Process of D406A Ultra-High Strength Steel
Authors: Liu De Gui , Chen Fu Long , Wu Hai Bao , Li Ji Zhen , Wang Jian Fei
Published: June 2021

D406A steel is a medium-carbon low-alloy steel, which has excellent comprehensive mechanical properties. It is widely used in the production of missiles and rocket barrels. In this paper, the spinning forming limit test and the intermediate heat treatment process of ultra-high-strength steel were used to explore the effect of spinning process and heat treatment on the properties of spinning parts. The research results showed that the reduction amount of the material made the material thinning rate approach the limit thinning rate. The final blank wall thickness was reduced from 15 mm to 3.0 mm when the cracking occurred. It was calculated that the material's power spinning limit thinning rate was 80%. The ferrite matrix after spinning showed a streamline distribution characteristic perpendicular to the thinning direction, and the precipitated carbides were uniformly distributed on the surface of the matrix, which had the characteristics of deformation and extension along the streamline. After the heat treatment, the structure of the spinning parts changed continuously. When the structure was quenched and tempered, the martensitic structure can be obtained, and the tempered martensitic structure was smaller. Furthermore a test piece for ultra-high-strength steel spinning technology has been developed, and the solutions discussed for flanging defects in the actual spinning process, and test data for the actual production of ultra-high-strength steel spinning parts accumulated.
Thread Galling Damage Mechanism and Prevention of a Low Alloy Steel Tubing Connection
Authors: Lou Qi , Li Fang Po , Du Wei , Liang Ming Hua
Published: June 2021

The pull out and well drop accident caused by serious thread galling damage of low alloy steel tubing connections were investigated in this paper. Representative samples were selected from five failure accidents, and the test and verification program were designed. Based on the experiment and analysis it is considered that the material used for tubing and the quality of thread processing meet the requirements of the standard. The field end of tubing connection pull out may be due to the serious thread galling damage, which reduced the joint strength. Using the torque-position control method to make-up the thread connections in oil field may ensure the connection quality and the connection strength, meanwhile, and hence to avoid the occurrence of tubing pulling out effectively.
Dendritic Growth of Rapid-Solidified Eutectic High-Entropy Alloy
Authors: Cao Lei Gang , Hou Peng Yu , Nassar Ahmed , Mullis Andrew M.
Published: June 2021

Mould casting and drop-tube techniques were used to solidify a AlCoCrFeNi2.1 eutectic high-entropy alloy under conditions of high cooling rate. The samples obtained from two different methods present the same phase constituent, FCC and B2 phases. During mould casting experiments the alloy almost solidified into the eutectic structure consisting of lamellar and anomalous morphology, with a tiny fraction of cellular and dendrite morphology being observed at certain sites of the sample surface due to the corresponding high cooling rate. Instead, during drop-tube experiments a typical, coarse dendrite structure of FCC single phase was formed across the entire 106-150 μm particle. The cellular structure can also be formed directly from the melt. The rest region solidified into the general eutectic morphology as was observed in the casting rods. The results clearly indicate the transition from coupled eutectic growth to single-phase dendrite growth with increasing departures from equilibrium for the multi-component AlCoCrFeNi2.1 eutectic high-entropy alloy.
Comparative Study of Surface Contaminated Layer on Titanium Aluminum Alloy and Titanium Alloy Investment Castings
Authors: Feng Zhi Hua , Ding Xian Fei , Feng Xin , Nan Hai , Zhang Ai Bin
Published: June 2021

A comparative study of the surface contaminated layer formed by chemical reaction between ceramic-mold and titanium aluminum alloy castings or titanium alloy castings were carried out. The morphology, thickness and hardness of the surface contaminated layer were characterized by means of metalloscopy and microhardness measurement. The results show that surface contaminated layers formed between Ti-Al alloy castings and ceramic-mold, also formed between Ti alloy castings and ceramic-mold. The surface contaminated layers of Ti-Al alloy castings were continuous and compact, their thickness was about 0~90 μm. The surface contaminated layers of titanium alloy castings were not even, their thickness was 0~900 μm. Titanium alloy is more liable to react with the ceramic -mold than the Ti-Al alloy.
Failure Analysis of Cracked and Corroded Tubings in Sudong Block of Changqing Oilfield
Authors: Zhao Xue Hui , Li Ming Xing , Liu Jun Lin , Liu Man
Published: June 2021

In the process of layer inspection and hole mending, it was found that the corrosion of tubing in a well was serious, and perforation and fracture occurred. Part of the tubing was found to be cracked from the failed pipe samples, and relatively serious pitting corrosion pits were found on the surface of the outer wall. The fracture morphology and corrosion products were analyzed by means of macroscopic analysis and metallographic microscope, SEM and EDS. The result show that the mechanical damage of the outer wall of the tubing was the primary condition for accelerating corrosion, and the severe corrosion thinning of the inner and outer walls of the tubing was the main reason for the failure of the tubing string. The corrosion perforation of tubing was mainly caused by internal corrosion.
Process Parameters Study on Structure and Properties of Zr-Based Bulk Metallic Glasses
Authors: Fan Jian Jun , Kou Sheng Zhong , Ding Rui Xian , Jiang Ye
Published: June 2021

The effects of different process parameters on the microstructure and mechanical properties of Zr-based bulk metallic glass were studied by using four factors and four levels of orthogonal experiment. Through the observation and analysis of the X-ray diffraction pattern, room temperature compressibility, microhardness distribution and transmission electron micrograph of the [Zr0.72-x(Cu0.59Ni0.41)0.28+x]88-yAl12+y (atomic percent) amorphous alloy with different process parameters, the results show that the compressive strength of the amorphous alloys with composition of [Zr0.73(Cu0.59Ni0.41)0.27]88Al12 and [Zr0.73(Cu0.59Ni0.41)0.27]87Al13 amorphous alloy under the corresponding processing parameters has reached 2411MPa and 1993MPa, and the plastic strain of the alloys is 33.8% and 19.3%. At the same time, through orthogonal analysis, in the four process parameters, the superheat temperature of the melt during the preparation of the alloy mainly affects the compressive strength of the alloy, while the cooling rate of the melt during the preparation of the alloy has a great influence on the plastic properties of the alloy.
Preparation and Properties of Calcium Doped Carbon Nanofibers Photothermal Reagent
Authors: Liu Shu Sen , Dai Jia Mu , Li Su Ying , Liu Rong
Published: June 2021

Recently, carbon nanomaterials illustrated great application prospect in tumor photothermal therapy (PTT). Meanwhile, numerous studies have shown that destruction of calcium homeostasis in cells can also be used as an effective strategy to inhibit tumor. Therefore, dual effect Ca2+ doped carbon nanofibers (PCNFs-Ca) photothermal reagents were prepared by electrospinning technique in this study. The spinnability, morphology and photothermal effect of different content of calcium doped carbon nanofibers were analyzed by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD) and infrared thermometer. The results suggested that a dual effect photothermal reagent with high Ca2+ content was prepared to achieve significant effect in tumor inhibition on the premise of less influence on the photothermal properties of carbon nanofibers.
Effect of Reaction Time on the Coercivity of Barium Ferrite Synthesized by Hydrothermal Process
Authors: Chen Min , Yin Yin Xuan , Qi Mei Li , Ding Yong Ling , Wang Yan Min
Published: June 2021

The barium ferrite BaFe12O19 with c-plane anisotropy, which possessed relative high saturation magnetization and low coercivity, had been synthesized by hydrothermal method with different reaction time of 5 h, 8 h,11 h,14 h, and 17 h. The X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer (VSM) were used to study the phase composition, microstructure and magnetic properties of barium ferrite, respectively. The results showed the intensities of the peak were enhanced and there was no impurity phase. With the prolonging of the reaction time to 11 h, 14 h and 17 h, the grain size increased, and the equivalent diameter was about 1 μm, and the thickness was about 100 nm. When the reaction time was 17 h，the coercivity of barium ferrite was 1104 Oe. The reduction of coercivity was ascribed to the increase of particle size and the reduction in magnetic anisotropy.
Gr/Cu Composites: Microstructure and Properties
Authors: Zhang Yu , Li Yan , Cao Jin Hua , Li Yan Chun , Song Mei Hui , Zhang Xiao Chen
Published: June 2021

Graphene(Gr) reinforced copper matrix composites(Gr/Cu) were prepared by powder metallurgy process, and the effects of graphene content on microstructure and properties of the composites were investigated. The microstructure, density, hardness and electrical conductivity of the composites were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), density measurement, hardness tester and conductivity meter. The results show that the interface bonding of the composite is good, there is no crack and no obvious interface reaction; there are a lot of dislocations and twins in Cu matrix. With the increase of graphene content, the density, heat capacity and thermal conductivity of the composites decrease, but the hardness increases first and then decreases.
Effects of Melt Ultrasonic Treatment and Forming Processes on Thermo- Physical Properties of SiCp/Mg and (SiCp+Mg2Si)/Mg Composites
Authors: Wu Shu Sen , Guo Tian , Lü Shu Lin , Guo Wei , Xia Lan Qing
Published: June 2021

The 10 vol% SiCp/Mg composites were prepared by external addition and stirring-casting method, and the hybrid reinforced (10 vol% SiCp+10 vol% Mg2Si)/Mg composites were prepared by combining in-situ method. The effects of melt ultrasonic treatment (UT) and forming processes on the thermophysical properties of the two composites were studied. The results show that UT can effectively disperse SiC particles in molten magnesium and reduce the casting porosity, while squeeze casting can significantly reduce the porosity of the composites, which can also significantly improve the thermal conductivity. The thermal conductivity (λ) of 10 vol.% SiCp/Mg composites squeeze casted after UT is 135.3 W/(mK) and the average coefficient of thermal expansion (CTE) is 19.95×10-6 K-1 at 293-373 K. Compared with gravity casting, the λ is increased by 17% and the CTE is reduced by 0.8%. The λ of (SiCp+Mg2Si)/Mg composite squeeze casted after UT is 132.4 W/(mK), and the CTE is 18.95×10-6 K-1, which is 27% lower than the CTE of pure magnesium.
Research on Microstructure and Properties of TiB2/Al-Si Multi-Element Piston Alloy Composite
Authors: Yang Zi An , Xiang Zhi Lei , Chen Zi Yong , Ren Wei Min , Li Zhong Hao , Tan Chao
Published: June 2021

The Al-12Si-4Cu-2Ni-0.9Mg was used as the matrix, TiB2/Al-12Si-4Cu-2Ni-0.9Mg composite material was prepared by adding Al-TiB2 in master alloy, and the mass fraction of TiB2 particles in the composite material was 3%. TiB2 particles were prepared by melt self-propagating direct synthesis method. Based on studying the influence of mechanical stirring speed on the distribution of TiB2 particles during the preparation of Al-TiB2 master alloy, the optimal mechanical stirring speed was optimized to 800 r/min. TiB2/Al-12Si-4Cu-2Ni-0.9Mg composite material was prepared by remelting and dilution method. The as-cast solidified structure of the composite material was mainly composed of α-Al matrix, Si phase and TiB2 particles, and TiB2 particles were evenly distributed. Under the condition of 360 °C(Working temperature of common piston), the tensile strength of the composite material was 15.4% higher than that of the base material, and the yield strength of the composite material was 29.4% higher than that of the base material.
Preparation and Thermal Properties of BN and LPSO Hybrid Reinforced Magnesium Matrix Composite
Authors: Xia Lan Qing , Wu Shu Sen , Li Chen , Guo Wei , Lü Shu Lin
Published: June 2021

Hexagonal boron nitride (h-BN) is a ceramic material with high thermal conductivity (TC) and low coefficient of thermal expansion (CTE), which can improve multiple thermal properties of metal-matrix composites as a reinforcing particle, but its wettability with metal melt is very poor. In order to enhance the wettability between the h-BN and magnesium alloy melt, the electroless plating was used to coat a thin layer of pure nickel on h-BN particles, which was proved to be effective and efficient in this study. The results showed that by adding Y element to magnesium alloy melt to consume Ni element melted from the nickel-plating layer, the long period stacking ordered (LPSO) structure composed of Mg-Ni-Y was successfully formed, and the magnesium matrix composite reinforced by hybrid h-BN and LPSO structure was obtained. After ultrasonic treatment (UT), the TC of the magnesium composite containing 3 vol% h-BN and 14.16 vol% LPSO is 99.92 W/(m·K), which is a 8.3% enhancement compare to the composite without UT. The average CTE (293-373 K) of the composite is 18.36×10-6 K-1, which is reduced by 29.4% compared with pure magnesium.
Improvement of Mechanical Properties of Cu/Graphene Composite by In Site Reduction and Matrix Alloying with Titanium
Authors: Li Ya Zhou , Zhao Yu , Ran Xu
Published: June 2021

To reduce the agglomeration of graphene and enhance the interface bonding between reduced graphene oxide (RGO) and copper substrate, copper plating on the graphene surface was prepared by the in-situ reduction method. To improve the strength of the copper matrix, the microalloying strategy of adding titanium to the matrix was adopted. By changing the mass fraction of titanium in the matrix, the optimum ratio of RGO was obtained( Ti mass fraction was 5:1), and the tensile strength was maximized. The results show that RGO did not agglomerate obviously in the matrix. At the same time, the composite powder could be densified rapidly by spark plasma sintering (SPS), which could effectively protect the original distribution of the additive phase in the matrix. In this paper, Cu@RGO/Cu-Ti was prepared and the strengthening mechanism of the composites discussed, providing a new insights into the interface design and carbide formation mechanism of advanced graphene/copper composites with high mechanical properties.
Research Progress on Low-Carbon Technologies and Assessment Methods in Cement Industry
Authors: Zhao Hai Tao , Liu Yu , Li Xiao Qing , Hao Li Wei
Published: June 2021

As one of the pillar industries for social development and economic construction, cement manufacture is energy and carbon-intensive, whose greenhouse gas (GHG) emissions account for more than 6% of total global man-made GHG emission annually. With the growing attention on the problem of global warming, researching and promoting low-carbon manufacturing technologies to reduce GHG emissions have become the main trend in the development of cement industry under the new era. This article sorted out the low-carbon technologies for cement production reported in recent years, introduced the mainstream methods of GHG accounting and assessment such as life cycle assessment (LCA) and carbon footprint analysis (CFA), meanwhile reviewed the articles in the field of low-carbon technology and assessment methods in cement production, moreover, discussed the merits and demerits of various assessment methods and applicable fields, in order to provide suggestions and supports for low-carbon transformation of cement industry.
A High Temperature SOI-CMOS Chipset Focusing Sensor Electronics for Operating Temperatures up to 300 °C
Authors: Kappert Holger , Braun Sebastian , Kordas Norbert , Kosfeld Andre , Utz Alexander , Weber Constanze , Rämer Olaf , Spanier Malte , Ihle Martin , Ziesche Steffen , Kokozinski Rainer
Published: June 2021

Sensors are key elements for capturing environmental properties and are increasingly important in the industry for the intelligent control of industrial processes. While in many everyday objects highly integrated sensor systems are already state of the art, the situation in an industrial environment is clearly different. Frequently the use of sensor systems is impossible, because the extreme ambient conditions of industrial processes like high operating temperatures or strong mechanical load do not allow a reliable operation of sensitive electronic components. Fraunhofer is running the Lighthouse Project ‘eHarsh’ to overcome this hurdle. In the course of the project an integrated sensor readout electronic has been realized based on a set of three chips. A dedicated sensor frontend provides the analog sensor interface for resistive sensors typically arranged in a Wheatstone configuration. Furthermore, the chipset includes a 32-bit microcontroller for signal conditioning and sensor control. Finally, it comprises an interface chip including a bus transceiver and voltage regulators. The chipset has been realized in a high temperature 0.35 micron SOI-CMOS technology focusing operating temperatures up to 300 °C. The chipset is assembled on a multilayer ceramic LTCC-board using flip chip technology. The ceramic board consists of 4 layers with a total thickness of approx. 0.9 mm. The internal wiring is based on silver paste while external contacts were alternatively manufactured in silver (sintering/soldering) or in gold-alloys (wire bonding). As interconnection technology, silver sintering has been applied. It has already been shown that a significant increase in lifetime can be reached by using silver sintering for die attach applications. Using silver sintering for flip chip technology is a new and challenging approach. By adjusting the process parameter geared to the chipset design and the design of the ceramic board high quality flip chip interconnects can be generated.
Coexistence of Autoantibodies and Other Autoimmune Diseases with Multiple Sclerosis and Related Disorders – Experience from the Mangalore Demyelinating Disease Registry (MANDDIR)
Authors: Malli Chaithra , Pandit Lekha , D’Çunha Mary A. , Sudhir Akshatha
Published: June 2021

Background:

Co-occurrence of other autoimmune disorders (AID) and autoantibodies in patients with autoimmune demyelinating CNS disorders have not been studied previously in patients of Indian origin.

Objective:

To determine the frequency of concomitant autoimmune disorders, anti-nuclear antibody (ANA) and antithyroid antibody (ATAb) and to evaluate the impact on clinical course of disease.

Materials and Methods:

A total of 111 patients with MS and 152 patients with non-MS demyelinating disorders were included. Demographics, clinical course and disability were recorded. History of other autoimmune disorders (AIDs) in patients and first degree relatives was noted. Serum ANA and ATAb were tested.

Results:

Concomitant AIDs were seen in 21% of MS and 19% of non-MS patients. Autoimmune thyroid disease was most frequent and seen in 10.8% of MS and 6.6% of non-MS disorders. Frequency of ATAb was significantly higher among MS group (MS 25.5% vs non-MS 13.2% P = 0.04) but that of ANA was similar between the 2 groups (MS 19.8% vs non-MS 26.9% P = 0.17). A positive family history of autoimmune disorders was noted in 20% of MS and 15.1% of non-MS disorders. Clinical course was unaffected by presence of concomitant AID and autoantibodies.

Conclusion:

Cooccurrence of autoantibodies and AID are seen in a significant number of patients with MS and non-MS disorders and influences clinical management.
Occupational Therapy for Reducing Disabilities in Persons with Disabilities in India
Authors: Kamalakannan Sureshkumar , Chockalingam Manigandan , Sethuraman Lakshmanan , Moorthy Shobana Devi , Muthuvel Thirumugam
Published: June 2021

Background:

The current evidence for occupational therapy practice, teaching, and research is replicated and implemented significantly from high-income countries in India. Therefore, a systematic review and an evaluation of existing evidence for occupational therapy (OT) to reduce disabilities including impairments, activity limitations, and participation restriction in persons with disabilities (PWD) in India are warranted.

Objectives:

The objective of this review was to evaluate the effectiveness of OT interventions for reducing disabilities in PWD in India.

Study Design:

Systematic review.

Methods:

We searched the Cochrane CENTRAL, MEDLINE, Embase, CINAHL, PsycINFO, AMED, and Web of Science. A hand search was also carried out in selected Indian journals, OT-specific databases, and repositories, such as Indian Journal of Occupational Therapy, Indian Journal of Physiotherapy and Occupational Therapy, OT Seekers, World Federation of Occupational Therapy Bulletin, Asia Pacific Occupational Therapists Regional Group, and clinical trials registers. The search was restricted to published studies conducted in India during 2000–2021. We included randomized controlled trials (RCTs) of an occupational therapy intervention delivered by OTs for PWD, where the effects of the intervention were evaluated using any relevant disability outcome measure. Studies without access to full text were excluded. Two review authors independently completed screening, and one author reviewed the full text of the screened studies. Another pair of authors extracted data from included studies for prespecified disability outcomes, and two authors assessed the risk of bias in the included studies.

Results:

We identified seven RCTs of occupational therapy interventions for PWD in India with 305 participants in total. All seven studies were very different in terms of their objective, participants, comparison, and outcomes. Allocation concealment and blinding and risk of bias were high in five trials. All the trials reported impairment outcomes with a statistically significant difference between the experimental arm and the control arm in terms of their primary outcomes except one. Given the sample size and the risk of bias in each of the included trials, the effect size has to be understood and interpreted with utmost caution.

Conclusion:

Overall, this review establishes the paucity of evidence for occupational therapy for PWD in India. Building the capacity for rigorous and relevant scientific research in occupational therapy would enable bridging the gaps in evidence for occupational therapy in India.
Effect of Occupational Therapy on Cognitive Functions and Occupational Performances in Hospitalized Patients with Mental-Health Disorder
Authors: Mehta Pooja Pankaj
Published: June 2021

Background:

Cognitive dysfunction, a distressing outcome of mental-health disorders (MHDs), hinders an individual's occupational performance (OP). OP is the outcome of dynamic interaction between a person, their unique environment and occupation. With only pharmacological treatment, symptom reduction was not in pace with the recovery rate of cognitive and OP dysfunction resulting persistence of these dysfunctions even post-hospital discharge. Hence, occupational therapy (OT) intervention before discharge would be required, for patient's functioning at premorbid level postdischarge. However, till date, very few Indian studies on the effect of OT on cognition and OP in individuals with MHDs are done with under-representation of the client population.

Objectives:

To study the effect of OT on cognitive functions and OP in hospitalized patients with MHDs.

Study Design:

A single-arm interventional study was conducted.

Methods:

Based on the selection criteria, 88 patients who were (aged 18–55 years) diagnosed with MHDs and were admitted in the hospital were enrolled after screening during their first visit to OT department using the purposive sampling method. Participants recruited were categorized into diagnostic groups: schizophrenia, neurotic disorders, mood disorders, and alcohol-substance use disorders for data analysis. Patients were assessed on Mini-Mental State Examination (MMSE) and comprehensive OT evaluation (COTE) scale pre- and post-therapy after 3 weeks, i.e. after 6 sessions. Cognitive-OP focused-OT intervention was given twice a week.

Results:

The descriptive data analysis showed an increase in performance posttherapy for all subtests (except Language-praxis subtest in Group-Neurotic Disorders) and overall scores of both assessments in all the groups. Total MMSE performance both pre- and post-therapy was better than total COTE performance in all the groups. Posttherapy, maximum improvement was observed in Recall among MMSE subtests and in Task-behavior among COTE subtests across all groups. Inferential data analysis showed highly significant improvement posttherapy for total MMSE and total COTE scores (P < 0.01, 95% confidence interval: Groups: schizophrenia [(−3.218, −2.302) and (15.991, 18.329)], neurotic disorders [(−3.169, −1.631) and (13.230, 18.970)], mood disorders [(−3.100, −1.650) and (15.095, 19.155)] and Group: alcohol and substance-use disorders [(−4.210, −1.456) and (17.855, 22.47)] respectively).

Conclusion:

OT intervention is effective in improving cognitive and OP in hospitalized patients with MHDs.
Effect of Nasal Dominance on Pulmonary Function Test and Heart Rate
Authors: Sinha Smriti , Mittal Swati , Bhat Shilpi , Baro Geeta
Published: June 2021

Background:

The nasal cycle is one of the many cyclic events in a human being. Nasal airflow is greater in one nostril at any given point in time and this alternates between right and left nostrils over time. Its periodicity ranges from 25 min to 8 h. This alteration has been known to be controlled by the autonomic nervous system. The current study was designed to assess the effect of nasal dominance during rest on pulmonary function parameters and heart rate.

Materials and Methods:

A cross-sectional study was done on 35 apparently healthy individuals of the age group of 18–30 years. Based on a cold mirror test, the participants were categorized into two groups of right nasal dominance (RND) and left nasal dominance (LND). The parameters recorded were forced expiratory volume in the first sec (FEV1), forced vital capacity (FVC), FEV1/FVC, peak expiratory flow rate, forced expiratory flow between 25%-75%, SpO2, and pulse rate. Data were expressed as mean ± standard deviation and were analyzed using SPSS version 20.

Results:

All pulmonary function parameters exhibited higher values in RND participants compared to LND participants and the difference was found to be statistically significant (P < 0.05).

Conclusion:

Nasal dominance has a measurable effect on pulmonary functions and heart rate hence emphasizing the role of autonomic control of airways. This influence can be used as adjuvant therapy for certain disorders.
Cardiovascular, Cellular, and Neural Adaptations to Hot Yoga versus Normal-Temperature Yoga
Authors: Bourbeau Kelsey Christian , Moriarty Terence A , Bellovary Bryanne Nicole , Bellissimo Gabriella F , Ducharme Jeremy B , Haeny Truman J , Zuhl Micah N
Published: June 2021

Context:

Chronic heat exposure promotes cardiovascular and cellular adaptations, improving an organism's ability to tolerate subsequent stressors. Heat exposure may also promote neural adaptations and alter the neural–hormonal stress response. Hot-temperature yoga (HY) combines mind–body exercise with heat exposure. The added heat component in HY may induce cardiovascular and cellular changes, along with neural benefits and modulation of stress hormones.

Aims:

The purpose of the present study is to compare the cardiovascular, cellular heat shock protein 70 (HSP70), neural, and hormonal adaptations of HY versus normal-temperature yoga (NY).

Settings and Design:

Twenty-two subjects (males = 11 and females = 11, 26 ± 6 years) completed 4 weeks of NY (n = 11) or HY (n = 11, 41°C, 40% humidity). Yoga sessions were performed 3 times/week following a modified Bikram protocol.

Subjects and Methods:

Pre- and posttesting included (1) hemodynamic measures during a heat tolerance test and maximal aerobic fitness test; (2) neural and hormonal adaptations using serum brain-derived neurotrophic factor (BDNF) and adrenocorticotropic hormone (ACTH), along with a mental stress questionnaire; and (3) cellular adaptations (HSP70) in peripheral blood mononuclear cells (PBMCs).

Statistical Analysis:

Within- and between-group Student's t-test analyses were conducted to compare pre- and post-VO2 max, perceived stress, BDNF, HSP70, and ACTH in HY and NY groups.

Results:

Maximal aerobic fitness increased in the HY group only. No evidence of heat acclimation or change in mental stress was observed. Serum BDNF significantly increased in yoga groups combined. Analysis of HSP70 suggested higher expression of HSP70 in the HY group only.

Conclusions:

Twelve sessions of HY promoted cardiovascular fitness and cellular thermotolerance adaptations. Serum BDNF increased in response to yoga (NY + HY) and appeared to not be temperature dependent.