bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental assessment of the influence of radiant heat transfer on the transition of a crown fire to settlements
Authors: Копылов Николай Петрович , Сушкина Елена Юрьевна , Кузнецов Александр Евгеньевич , Новикова Виктория Ивановна
Published: June 2021

Проведены экспериментальные исследования влияния лучистого теплообмена на переход верхового лесного пожара на постройки IV и V степеней огнестойкости. Лесной верховой пожар моделировался горением штабеля древесины с интенсивностью тепловыделения, близкой к интенсивности при реальных пожарах. Получена зависимость изменения плотности теплового потока от расстояния до кромки горения. Экспериментально определены температура воздуха с подветренной стороны пожара и плотность выпадения искр в зависимости от расстояния. Проверена эффективность защиты растворами ретардантов деревянных строений от возгорания при лучистом теплообмене между факелом пламени пожара и объектом защиты.

Crown fires are the main threat of the combustion transfer from the forest to objects located in it. Fire services dealing with forest fires face the problem how to protect these objects from forest fires. It is proposed to treat the object with retardant solutions before a forest fire approaches. To assess the effectiveness of such tactics for fire protection of objects when exposed to a heat flow from the combustion front there were carried out experiments on large-scale crown fire models. A crown fire is simulated with a pile of wood with a heat release rate of ≈ 13 MW m. The wind is generated by fans, its speed is close to the speed at which a forest fire occurs. Measurements of the heat flux density, medium temperature, and the density of sparks falling downwind of the fire front at different distances and heights were carried out. Calculations were carried out to assess the impact of heat flow on buildings of IV-V degrees of fire resistance. The results obtained are compared with experimental data and they are in good agreement. There have been determined the distances from the fire front at which the fire protection with retardant solutions is effective for structures of IV-V fire resistance degrees at radiant heat exchange.
Analisis Customer Relationship Marketing Terhadap Kepuasan Dalam Meningkatkan Loyalitas Nasabah PT. BNI (Persero)
Authors: Wardani Sri , Zulkarnain Zulkarnain , Samsir Samsir
Published: June 2021

The study was conducted at Bank BNI (Persero) Tbk Regional Area Pekanbaru. The aim is to find out the direct effect of the CRM Dimension, namely Trust, Communication, Commitment, Conflict handling, Emphaty on customer satisfaction and loyalty. This study took a sample of 100 consumers. The variables used are Trust, Communication, Commitment, Conflict handling, Emphaty on customer satisfaction and loyalty. Data were analyzed using SEM (Structural Equation Modeling) analysis which is operated through the Smart PLS 3.2.8 program. The results showed that there is an influence of Trust, Communication, Commitment, Conflict handling, Emphaty on customer satisfaction and loyalty. And there is an influence between customer satisfaction variables on customer loyalty, the better the customer satisfaction, the better customer loyalty will be.
Pengaruh Mekanisme Good Corporate Governance Dan Struktur Kepemilikan Terhadap Pengungkapan Sustainability Report
Authors: Kholmi Masiyah , Nizzam Zein Susadi Muhammad
Published: June 2021

This research has a purpose to analysis the effect of good corporate governance mechanism and ownership structures on the disclosure of sustainability reports. Purposive sampling method was applied sampling technique certain of criteria. The sample is 47 companies from a population of 627 companies listed on the Indonesia Stock Exchange (BEI) in 2018. Data collection techniques used the documentation method. This research uses data analysis tools with the Smart PLS 3 application to test hypotheses. The results showed that the variables of good corporate governance mechanisms that were proxied by the audit committee, the independent board of commissioners, and the board of directors had a significant effect on the disclosure of sustainability reports, ownership structure variables that were proxied with managerial ownership, institutional ownership, and foreign ownership also affected the disclosure of sustainability reports
Anuario Meteorológico Cafetero 2009
Authors:   Centro Nacional de Investigaciones de Café
Published: June 2021

En este anuario meteorológico se publica información registrada en la red climática de la Federación Nacional de Cafeteros de Colombia operada por la Disciplina de Agroclimatología de Cenicafé.
Anuario Meteorológico Cafetero 2013
Authors:   Centro Nacional de Investigaciones de Café
Published: June 2021

En este anuario meteorológico se publica información registrada en la red climática de la Federación Nacional de Cafeteros de Colombia operada por la Disciplina de Agroclimatología de Cenicafé.
Coordination, attention visuelle et gestes professionnels dans la rééducation de l’aphasie
Authors: Merlino Sara
Published: June 2021

Dans cette contribution, nous nous focalisons sur des interactions entre personnes aphasiques et orthophonistes au cours des séances de rééducation de la parole. En soulignant la nature interactive et multimodale des activités thérapeutiques, notre étude se penche sur des phénomènes de coordination et d’établissement et négociation de l’attention visuelle. L’analyse porte sur une collection d’extraits dans lesquels le thérapeute sollicite le regard du patient par l’emploi de plusieurs ressources, dont des directifs qui portent sur le regard. Ces sollicitations permettent de guider l’attention visuelle envers certains éléments du contexte et de négocier des configurations participatives adéquates pour profiter des formes d’étayage offertes par le thérapeute et accomplir les tâches de manière collaborative. Nous soulignons la centralité des gestes professionnels et des ressources corporelles mobilisés par le thérapeute et nous analysons la manière dont le patient est « instruit » à voir ces ressources. En reprenant plusieurs aspects de l’œuvre de Goodwin, notre contribution souligne des pratiques interactives et socialement organisées dans lesquelles prend forme l’institution thérapeutique de traitement de l’aphasie.
Folie partagée aux Grands Voisins
Authors: Habchi Sihem , Mazel Marine
Published: June 2021

L’article relate la prise en charge de la vulnérabilité et de la « folie » des résidents du site des Grands Voisins, tout particulièrement à travers les activités d’accompagnement que les associations Aurore et Yes We Camp ont proposées pour le projet d’insertion « Les Comptoirs du projet Food », qui a réuni des cuisiniers professionnels et non professionnels autour d’une expérience de cuisine partagée.
Déférence métropolitaine
Authors: Milon Alain
Published: June 2021

Le philosophe Alain Milon propose ici une réflexion sur les notions de « déférence » et de « trans-hospitalité métropolitaine » dans les lieux par définition hospitaliers de la ville (hôpitaux, hospices, hôtels ou pensions), et analyse tout particulièrement les formes qu’elles prennent dans les pratiques quotidiennes associées aux transports en commun urbains et notamment, le métro parisien.
The Judgment of the European Court of Justice of 22 September 2020 C-724/18 and Its Impact on the Real Estate Market in the EU
Authors:   Institute of Law, Cracow University of Economics, Kraków, Poland, Badura Ewelina
Published: June 2021

In 2020 two significant events affected the property market. The first one was the pandemic of COVID-19, which brought unprecedented uncertainty and resulted in a dramatic drop in property prices on rental market and hampered growth of the sales market. Another significant event this article is going to examine was the judgment C-724/18 of the European Court of Justice issued on 22 September 2020. The ECJ ruled that the authorisation scheme for short-term rental does not constitute a breach of the freedom of services warranted by the EU. The judgment concerns the legitimacy of the constraints imposed by local authorities on entrepreneurs operating short-term rentals. It also establishes the applicability of the EU’s Services Directive (2006/123/EC) to short-term rental. The ECJ holds in the judgment that the measure requiring an authorisation for short-term rental aimed tackling shortage of long-term rental housing represents an overriding reason of public interest and as such it is justified. The article analyses the consequences of the ECJ judgment for the market of short-term rentals, in view of the existing legal regulations and in respect of its possible consequences for short-term rental in the EU member states.
0D Zn-ZIF/2D Co-ZIF Derived 0D ZnO/2D Co3O4 Heterostructures for ppb-Level Acetone Detection
Authors: Chang Xiao , Xiong Ya , Xue Qing Zhong
Published: June 2021

Detecting acetone is meaningful in industrial processes and medical fields. Herein, 0D Zn-ZIF/2D Co-ZIF derived 0D ZnO/2D Co3O4 heterostructures are originally designed to improve acetone sensing properties. It is found that when the temperature is 250 °C, the 0D ZnO/2D Co3O4 possesses the highest response (4.73) to 5 ppm acetone, which is about three times more than that of pure 0D ZnO and pure 2D Co3O4. The detection limit of 0D ZnO/2D Co3O4 sensor could be as low as 100 ppb. The response/recovery time of 0D ZnO/2D Co3O4 sensor to 100 ppm acetone is only 3 s/15 s. It is demonstrated that with the introduction of 0D ZnO, the stacking of 2D Co3O4 nanosheets is inhibited and p-n heterojunctions are formed, which could significantly enhance acetone sensing performance.
Preparation of Pd/PPy/Foam-Ni Electrode and its Electrocatalytic Hydrodechlorination of Dichlorophenols
Authors: Ma Zhen Peng , Zhang Shu Xia , Yang Zhi Gang
Published: June 2021

Based on mechanism of ECH (Electrocatalytic Hydrogenation),the Pa/PPy/Foam-Ni (Pd/PPY/Ni) prepared by electrical depositing was used as cathode to detoxifythree kinds of dichlorophenol (DCP) and improve their biodegradability. According to the dechloridation ability of electrodes prepared under different conditions, the factors were optimized. The removal efficiency of 2,4-dichlorophenol（2,4-DCP）reaches 64.45% when the supporting electrolyte is p-toluenesulfonic acid and the voltage is 0.6V and polymerizing time is 20mins. Analyzing the photograph from SEM (Scanning Electron Microscope), it shows that PPy (PolyPyrrole) changes depositing properties of Pa on foam-Ni substrate, which increases specific surface area and special ductility so as to benefit Pd to deposite on Ni substrate and improve ECH.
Microstructure Evolution and Meta-Dynamic Recrystallization Behavior of Ti-45Al-8.5Nb-0.2W-0.2B-0.3Y Alloy during Inter-Pass Annealing after Deformation
Authors: Xiang Lin , Tang Bin , Tao Jian Quan , Chen Qiang , Xing Zhi Hui , Gao Shi Qing , Li Ming , Li Jin Shan
Published: June 2021

The effect of processing parameters on meta-dynamic recrystallization (MDRX) and the microstructural characteristics evolution of TiAl alloy with high Nb containing during annealing period were studied through double-pass hot compression tests. The results indicated that the occurrence of MDRX had a strengthening effect to flow behavior of the present alloy, resulting in grain equalization. And the high temperature and large strain were beneficial for the occurrence of MDRX, resulting in the increase of recrystallization grains. For the present alloy, MDRX rate is low, hence, enough annealing time is needed for MDRX during inter-pass annealing. Besides, dislocation density is consumed with the occurrence of MDRX.
NO Reduction Using Coal and Active Carbon with and without Catalysts
Authors: Li Nan , Wang Ya Li , Cui Su Ping
Published: June 2021

Reducing NO using coal and active carbon with and without the addition of catalysts were investigated in a fixed bed reactor at a wide temperature of 250-850 °C. The results indicated that without the catalysts, NO reduction using coal was significantly better than that using active carbon. When coal was used as reducing agent, the addition of catalysts made the NO reduction occurred earlier and the effect of catalysts was temperature-dependent. When active carbon was used to reduce NO, the addition of catalysts was not ideal and only CuO showed a significant positive effect above 700 °C.
Effect of Zr on the Microstructure and Mechanical Properties of Al-Zn-Mg-Cu Alloy with High Zn/Mg Ratio
Authors: Xu Yong Tao , Zhang Zhi Feng , Gao Zhi Hua , Bai Yue Long , Zheng Han Sen , Mao Wei Min
Published: June 2021

The high-strength Al-Zn-Mg-Cu alloy has broad application prospects in high-end equipment manufacturing fields, such as aerospace, national defense and military industry, and transportation. However, the grains of Al-Zn-Mg-Cu alloy are coarse, and the grains further grow after heat treatment, which seriously reduces the mechanical property of alloy castings. Therefore, the study on reducing the grain size of the cast alloy was carried out by adding Zr element and applying electromagnetic stirring treatment technology, as well as suppressing the recrystallization of the aluminum alloy during the heat treatment process. The results show that adding Zr element reduced the grain size by 30%, the tensile strength increased by 50 MPa, and the elongation increased by more than 10%.
Flow Cessation Mechanism of β-Phase Solidification of High-Nb Tial Alloy
Authors: Gong Zi Qi , Wu Jin , Du Hui Qi , Chai Li Hua , Chen Zi Yong
Published: June 2021

The spiral fluidity sample was poured by the liquid of Ti-45Al-8Nb-0.2W-0.25Cr alloy. The flow cessation mechanism of TiAl based alloys was investigated, and its model was built through the observation on the macrostructure of TiAl based alloys formed in the channel. The results showed that the morphology and size of the columnar crystal and equiaxial crystal changed a lot with the increase of flow length. The flow cessation mechanism of the alloy is the abundant growth of columnar crystal in the root, which causes to form the structure and finally give rise to the “necking” leading to flow cessation.
Forming Process of Wire and Arc Additive Manufacture
Authors: Zou Lei , Li Lei , Cai Jian Hua , Yang Hai Ying , Chen Jun
Published: June 2021

The forming process of wire and arc additively manufacture (WAAM) was studied using the self-developed and designed WAAM system. The single-pass and single-layer weld bead samples were prepared with different process parameters, and the cross-sectional dimensions of the weld bead were measured. The influence rules of weld current, welding speed, wire feed speed and welding height on the weld bead size were obtained. In addition, the overlap experiment of the WAAM forming process was also carried out. The multiple and multilayer lap samples with different overlap rates were prepared, and the cross-sections of the lap samples were observed and analyzed. Finally, the overlap rate range of 35-45% with good forming effect was obtained.
Second Phase Particles and Mechanical Properties of 2618 Aluminum Alloy Ring
Authors: Jiang Jing Ze , Li Bao , Yang Bi Cheng
Published: June 2021

2618 aluminum alloy has been used in aerospace structural parts, but the coarse second phase particles agglomerated in the alloy usually result in poor mechanical properties. In this paper, the morphology and distribution of the second phase particles and the mechanical properties of 2618 aluminum alloy ring were investigated, and the fracture morphology is observed by scanning electron microscope (SEM) and analyzed by energy dispersive X-ray spectroscopy (EDS). The result show that the mechanical properties in the axial direction are lower than those in the circumferential direction. It is evidentially shown that the agglomeration of Al9FeNi intermetallic particles and magnesium oxides in the fracture is the main reason for the poor mechanical properties in the axial direction.
Microstructure of Additive Manufactured Ti6Al4V by Electron Beam Melting
Authors: Wang Nan Nan , Zhu Bao Hong , Li De Fu , Yu Zhi Shui , Li Zhong Wen , Liu Zhi Guo , Yao Si Yu
Published: June 2021

The electron beam melting-printed Ti6Al4V shows a great potential application for orthopedic implants and aerospace in recent years. A systematic study on the microstructure of additive manufactured Ti6Al4V by electron beam melting both parallel to and perpendicular to the building directions (Z axis) is presented in the present investigation. The results showed that the microstructure of the alloy was α lamina with HCP structure and β bar with BCC structure. The original β phase grew as columnar crystal along the direction of construction, showing an equiaxial shape in the cross section, numerous small α lamellae block the original β phase, and presenting a cluster distribution on the original β grain boundary, and a basket-like distribution in the original β grain. This may be due to the rapid cooling of the small pool after melting, the repeated heating of the subsequent constructed layer on the formed layer, and the subsequent limited vacuum cooling, resulting in the formation of the micro morphology, which leads to the original β grain boundaries broken, and the formation of a distinctive basket or widmanstatten structure [1, 2]. In addition, XRD results indicated that there was α′ martensite, part of which has been decomposes into α phases and β phases, SEM and TEM experiments also proved this. Of note is that random distribution dislocation was observed in TEM. Using EBSD results, and it may be understand that the sample build direction was parallel to [0001] crystal orientation and build plane parallel to (1210) and (1100) crystal facets.
Effect of Temperature on the Cyclic Stress Amplitude of ENiCrFe-1 Ni-Based Alloy Electrode and its Mechanism
Authors: Zhang Qun Bing , Zhang Jian Xun , Wei Wen Lan
Published: June 2021

Ni-based alloy welding material has been widely used in the welding and post-welding repair of high-temperature materials. The effect of temperature on the cyclic stress amplitude of ENiCrFe-1 Ni-base alloy electrode was studied under the same strain condition. The results showed that when the temperature was lower than 400 °C, it presented the characteristics of cyclic hardening and then cyclic softening. When the temperature was higher than 500 °C, it presented the characteristics of cyclic hardening and then cyclic stability. The main reason is that with the temperature increase, the dislocation structure changed more and more stable. The results not only enrich the internal mechanism of fatigue behavior of nickel-based alloy welding materials, but also have important reference value for improving the structural safety of welded joints.
Characterization of Hot Deformation Behavior of Ti-Al-Nb-Zr-Mo-Cr Alloy
Authors: Zhu Li Wei , Zhu Zhi Shou , Wang Xin Nan
Published: June 2021

The hot deformation behavior of Ti-Al-Nb-Zr-Mo-Cr titanium alloy has been investigated using a Gleeble-1500D thermal simulation test machine in the temperature range of 855°C~1015°C,at constant strain rate from 0.01 s-1 to 10s-1 and with height reduction of 45%. The ﬂow curves characteristic under different deformation parameters show significant difference. According to the stress-strain curves of the alloy and its stress characteristics, the Arrhenius constitutive equation was obtained. The average activation energy is about 541 kJ/mol in the α+β field, and about 243 kJ/mol in the β field, respectively. Based on the dynamic materials model, the processing map is generated, which shows that the peak efficiency domain appears at the temperature of 874°C~900°C and the strain rate of 0.001 s-1~0.06s-1 with a peak efficiency of 0.58 at about 887°C/0.001s-1.
Effect of the Service Temperature on the Strength Plasticity and Fracture Mechanism of Cr-Mo Casing Steel
Authors: Wei Wen Lan , Cao Yin Ping , Cui Lu , Cheng Jia Rui , Wei Ze Bing , Guo Long Long , Zhang Ya Fei
Published: June 2021

In recent years, the oil and gas well casing is confronted with more complex service environment, and the casing is subjected to higher service load and temperature. In this study, the strength and plasticity of Cr - Mo low alloy casing steel of 80, 90 and 110 steel grades commonly used under high temperature service conditions was studied. The results show that with the increase of temperature, the yield strength and tensile strength of casing steel decreased. The sensitivity of high steel grade to temperature change was higher than that of lower steel grade; with the increase of steel grade, the fracture mechanism of casing steel changed from microporous polymerization fracture induced by large size second phase particles to shear propagation fracture induced by sub grain boundary microporous polymerization. This study has important guiding significance for the service safety and strain design of high grade steel under high temperature conditions.
Surface Performance of Chrome-Free Anti-Fingerprint Zinc and Zn-Al-Mg Coated Steel
Authors: Chen Hao Tian , Song Ren Bo , Wei Huan Jun , Huo Wei Feng , Yang Li Fang
Published: June 2021

A principle investigation of the fingerprint resistance, alcohol resistance, solvent resistance, humidity resistance, high temperature resistant yellow degeneration and black tarnish resistance of pure Zinc and Zn-Al-Mg coating were performed in this study. To detect above surface performance and make some constructive suggestions, a series of simulations experiments and a surface performance evaluation system based on light color differentiation measurement instrument were designed. The results show that the two products both can meet the needs of users in above-mentioned surface performance, besides pure Zinc coated product has more advantages in this performance in comparison to Zn-Al-Mg coated product. Users should pay attention to clean the fingerprint regularly which attached to the surface of the steel plate during use and the protection with the exposed surfaces of the steel during shipping.
Failure Analysis of Tee in Shale Gas Transportation Platform
Authors: Ji Nan , Feng Jie , Long Yan
Published: June 2021

The mains reasons for internal corrosion failure and cracking of the tee in shale gas transportation platform have been proposed based on macroscopic analysis, physical and chemical property test, metallographic examination, Scanning Electron Microscope analysis, X-ray spectroscopy analysis and service condition analysis. The results show that corrosion occurring in the inner wall of tee was caused by the combined impacts of CO2 corrosion, sulfate-reducing bacteria (SRB) corrosion and erosion corrosion. The crack in the weld of the inner wall was mainly due to the Sulfate-reducing Bacteria Induced cracking.
Effect of RE Elements Addition on Corrosion Behavior of Mg-Zn-Ca Amorphous Alloys for Biomedical Applications
Authors: Chi Yu Chen , Guan Bao Ru , Chen Feng , Qin Feng Xinag
Published: June 2021

The effects of rare earth (RE) elements (La, Y) addition on thermal stability and corrosion behavior of Mg68Zn28Ca4 amorphous alloys were investigated in this paper. The investigated Mg-Zn-Ca-RE amorphous alloys exhibit good thermal stability and enhanced corrosion resistance. The enhanced corrosion resistance of the RE-containing amorphous alloys is owing to the enrichment of the Zn and RE elements in the oxide layer. The corrosion resistance is further improved with the increasing of RE content.
Microstructure and Properties of Laser-Selected Melt-Formed AlSi10Mg Alloy
Authors: Liu Ran , Gao Yuan , Zhang Si Jie
Published: June 2021

The AlSi10Mg alloy samples were prepared by laser selective melting technology, and the effects of laser power, scanning distance and powder thickness on the microstructure, density and mechanical properties of the formed AlSi10Mg alloy samples were studied. The results showed that the phases of the AlSi10Mg alloy formed by laser melting in the selected area are mainly α-Al matrix and eutectic Si; the forming parallel to the direction of the component forms a typical fish scale structure, which is formed after the laser scanning molten pool solidifies , Its growth direction is parallel to the direction of heat dissipation; as the laser energy density decreases, the height of the fish scale tissue decreases and the width increases; when the laser power is higher, the density of the formed sample is also higher; the laser power is 900W, The sample with a scanning distance of 0.09mm and a spreading thickness of 0.05mm has better performance. The tensile strength and elongation of the sample parallel to the component direction are 288MPa and 2.1%, respectively.
Research Progress on Corrosion Resistance of Titanium Alloy Oil Well Tubing
Authors: Zhang Fang Fang , Feng Chun , Zhu Li Juan , Song Wen Wen
Published: June 2021

Compared with aluminum alloy and alloy steel, titanium alloy has higher specific strength, lower modulus of elasticity, and better toughness, fatigue performance and corrosion resistance. In terms of oil well tubing, the development of titanium alloy lags behind that of aluminum alloy and alloy steel. Aluminum alloy tubing is sensitive to pitting, fatigue corrosion and stress corrosion cracking. At the same time, it is not suitable for ultra-deep wells due to temperature limitations. Easily interact with corrosive media to cause corrosion and cracking. Titanium alloy oil well tubing is expected to solve this corrosion problem, but its corrosion resistance research is still incomplete. Therefore, it is necessary to develop titanium alloy oil well tubing with good corrosion resistance to improve corrosion fatigue (CF), fatigue during deep oil well and natural gas drilling operations. Catastrophic brittle fracture caused by hydrogen induced cracking (HIC), pitting corrosion and sulfide stress cracking (SSC). In this paper, by investigating a large number of domestic and foreign documents, the corrosion types of titanium alloy oil well pipes are analyzed, and the research status of corrosion resistance of titanium alloy oil well pipes is reviewed from three aspects: oil pipes, casings and drill pipes.
Surface Effect in a Metastable β Ti-Nb-Sn Alloy
Authors: Qi Li Chun , Qu Wen Xiao , Zhu Yong Qi , Liu Qing
Published: June 2021

The phase compositions of surface and interior in Ti-32Nb-4Sn metastable b alloy were investigated. It was found that this alloy exhibits surface effect significantly different from the effects reported in Ti-10V-2Fe-3Al, Ti-22Nb-9Zr and the other titanium alloys. The surface of Ti-32Nb-4Sn specimen quenched from single b phase region was characterized by dominant b phase and a few of α″ and ω phase. While in the interior of the alloy, a large amount of α² martensite phase was observed in addition to b phase The orientation relationship between the α″ martensite and β phase is (110)β∥(002)α″, (020)β∥(022)α″ and [001]β∥[100]α″.
Microstructure and Texture Evolution of Repetitive Upsetting-Extruded (RUEed) Mg-Gd-Y-Zn-Zr Alloy after Hot Compression
Authors: Dong Bei Bei , Zhang Zhi Min , Yu Jian Min , Che Xin
Published: June 2021

In order to determine the deformation temperature of next pass, the hot compression tests were performed by Gleeble-3800 at different temperature form 380 to 420 °C. The microstructure and texture evolution of repetitive upsetting-extruded (RUEed) Mg-Gd-Y-Zn-Zr alloy during hot compression were studied by electron backscattering diffraction (EBSD) analysis. The results showed that the dynamic recrystallization (DRX) occured during the hot compression processing from the strain-stress flow curves. When the temperature increased to 420 °C, the average grain size reduced to 6.64 μm, and the volume fraction of DRXed grains increased to 81.5%. All the compressed alloys exhibited a typical compression texture, the maximum texture intensity of {0001} plane gradually decreased with increasing temperature. When the compression temperature was up to 420°C, the the maximum texture intensity of {0001} plane was 3.207 due to the effect of DRXed grains. Finally, 420°C is chosen as the next deformation of next pass because of the more precipitation and DRXed grains.
Transdisciplinary Application of Functional Materials in Petroleum Engineering
Authors: Zhao Gu Fan , Wang Rui Yao
Published: June 2021

Currently, transdisciplinary integration has become increasingly close, and has gradually become the source of innovation. At the same time, petroleum engineering technologies demand more new technologies like functional materials and electronic information technologies. In order to effectively promote technological innovation and development of the petroleum engineering, it is important to continuously monitor, analyze and evaluate the latest development of the technologies outside of the oil and gas industry. This paper combines qualitative analysis of onsite demands, application cases, technical characteristics, and quantitative analysis of literature metrology, patent evaluation, technology maturity, to evaluate the application prospects of densified wood, liquid metal and poly (thioctic acid) in the field of petroleum engineering, and specific transdisciplinary suggestions are put forward. It is recommended to carry out pre-research work for the potential application of functional materials in the petroleum engineering, and it is expected to introduce new materials for downhole tools, new antennas for downhole instruments, extend long-term effectiveness of downhole plugging, and improve drilling efficiency.
Fabrication of Y2Ti2O7 Transparent Ceramic by Spark Plasma Sintering
Authors: An Li Qiong , Shi Rong Wei , Fan Run Hua , Goto Takashi
Published: June 2021

Y2Ti2O7 transparent ceramic was fabricated by reactive sintering using spark plasma sintering at 1673 K for 2.7 ks. The sintered body exhibited a cubic pyrochlore structure and uniform microstructure with an average grain size of 2.9 μm. The transmittance reached 73% at a wavelength of 2000 nm after annealing at 1023 K for 21.6 ks.
Diffusion Bonding Performance of Copper Target for 300mm Integrated Circuit
Authors: Guo Shan Shan , Jiang Yuan Yuan , Zeng Hao , Wan Xiao Yong , Li Yong Jun
Published: June 2021

Ultra-pure copper sputtering target is a key material widely used in large-scale integrated circuits with 90-28 nm feature size. The copper target for 300 mm integrated circuit requires a reliable diffusion bonding between the ultra-pure copper target and the copper alloy backplate. The bonding ratio and bonding strength of diffusion bonding should reach over 99% and 80 MPa respectively. In this paper, the ascendant structure of electron beam welding united diffusion bonding with high quality was designed. The ultra-pure copper target and the C18000 copper alloy backplate were machined to coordinating size, meanwhile the backplate underwent surface treatment of toothed/smooth, ion cleaning, magnetron sputtering coating, then the combination of target and the backplate was proceeded electron beam welding and diffusion bonding. Metallographic microscope, scanning electron microscope (SEM), mechanical tensile machine, C-scan flaw detector were used to analyze the bonding properties including interface microstructure, bonding strength and bonding ratio. The results show that the bonding ratio of copper target was above 99%, and the bonding strength was up to 80-160 MPa.
Molten Salt Synthesis of Multiple Manganese Oxides/Graphene Composites in Facile and Large Scale with Enhanced Supercapacitor Performance
Authors: Tan Ning , Lei Yan Hua , Sun Kai , Sun Shi Bin , Gao Guan Hui
Published: June 2021

A facile and effective approach to assemble graphene hybridized multiple manganese oxides /graphene ((m-MnO2/Gr) was explored. The structure varied from two-dimensional (2D) to one-dimensional (1D) club-shaped manganese oxides via blending of Gr into the molten salt precursor. Compared to the m-MnO2 and pristine Gr electrode, the m-MnO2/Gr composites displayed a superior synergistic effect in promoted capacitive performance, cycle performance, with capacity retention of about 90% after 2000 charge-discharge cycles. It expects to supply a promising strategy to synthesize large scalable production of hybrid supercapacitor electrode.
Research on Micro-Size Electrical Discharge Grinding Polycrystalline Cubic Boron Nitride Based on Single Pulse
Authors: Jia Yun Hai , Cia Yan Hua , Zhang Qin Jian
Published: June 2021

Polycrystalline cubic boron nitride (PcBN) was a high temperature and high pressure composite material with high hardness. With its high wear resistance and good chemical stability, it conforms to the basic characteristics of modern advanced cutting technology of "high efficiency, high precision, high efficiency and green". Currently, it was widely used in the field of ferrous metal cutting tools. Electrical discharge grinding was one of the most effective methods for machining polycrystalline cubic boron nitride cutters. It was especially suitable for machining complex shapes and thin edge cutters. Single pulse electrical discharge grinding is the basis of continuous EDG machining and an effective method to study micro-scale electrical discharge grinding. In this study, the morphology of single pulse discharge corrosion pits and the relationship between discharge parameters and material removal rate, such as the deep-diameter ratio of the corrosion pits, the pulse width and the deep-diameter relationship of the corrosion pits, were studied with the polycrystalline cubic boron nitride composite sheet of 2 micron particle size as the test material and the independently developed single pulse discharge power supply as the device. The experimental results show that the radius and heat affected area of the discharge corrosion pit increase rapidly, then slowly, and finally gradually with the extension of pulse duration. The corrosion depth generally varies gently in the range of 0.2 ~ 0.5 micron, and the pulse duration has no obvious effect on the depth of the discharge corrosion pit. With the extension of pulse duration, the ratio of radius to depth of the corrosion pit changed in the range of 13 ~ 20, and the ratio basically declined.
Simulation and Experimental Study of the Preheating Mould Temperature Distribution in Semi-Solid Diecasting
Authors: Gao Chao , Luo Min , Li Da Quan , Chen Song , Feng Jian , Zhang Fan , Zhang Fan
Published: June 2021

The mould temperature distribution has a great influence on the semi-solid diecasting. In the present study the temperature distribution of a plane-shaped mould was investigated by using the method of numerical simulation and experiment. The results showed that the preheating mould temperature field was affected by three important simulation parameters, the heat transfer coefficient hoil between the heat transfer oil and the mould, the heat transfer coefficient hair between the mould and the air, and the heat transfer coefficient hcontact between the mould core and the mould frame. The simulation results showed that (1) with the increase of hoil, the overall mould temperature imcreased; (2) with the increase of hair, the overall mould temperature decreased, while the surface temperature gradient of mould frame grad T-f and the temperature difference between the mould core and the mould frame ∆T increased; (3) With the increase of hcontact, ∆T decreased and the temperature of mould frame increased. When the heat oil temperature Toil=290°C, the heat transfer coefficients were optimized as hoil=500Wm-2K-1, hair=7Wm-2K-1, and hcontact=1000Wm-2K-1 according to the experimental results. The average temperature difference between the simulation result and the experimental result was 3.45°C, and the average relative error was 1.73%.
Microfluidic Fabrication of Helical Ca-Alginate Hydrogel Fibers
Authors: Chen Sha , Gong Jing Hua , Ma Jing Hong
Published: June 2021

Helix is a sophisticated structure in nature and has many unique functions which makes it possible to store more information and energy, even receive more sensitive signals. Besides, as an effective method for preparing hydrogel fibers, microfluidic spinning has achieved unprecedented development in the past decade. However, hydrogel fiber with helical structure has began to be studied only in recent years. In this paper, the helical hydrogel fibers were prepared by the microfluidic spinning method. The microfluidic chip was assembled by PDMS connector, collection tube, inner and outer channels. Sodium alginate (SA) and calcium chloride were used as the core fluid and sheath fluid, respectively. By designing and adjusting the length of the chip, changing the concentration of SA and the ratio of two flow rates (inner flow rate/outer flow rate), a continuous and uniform helical hydrogel fiber was prepared. The relationships between the diameter of the fiber, the pitch of the helix and the concentration of SA, the ratio of two flow rates were discussed. The results showed that the diameter of the fiber was mainly affected by the core fluid. Within a certain range, as the concentration of SA increased, the diameter of the fiber increased. Besides, the pitch of the helix was greatly affected by the flow rate of sheath fluid. As the velocity of the sheath fluid increased, the pitch of the fiber increased. Such helical fiber could be used in micro sensors when added some conductive materials or crosslinked with some temperature responsive polymers such as N-isopropylacrylamide.
Quasi-State Compressive Properties of Functionally Graded Aluminum Matrix Syntactic Foams
Authors: Su Ming Ming , Li Mo Qiu , Fiedler Thomas , Hao Hai
Published: June 2021

The uniform aluminum matrix syntactic foams (SFs) were prepared by the stir casting method, with alumina hollow spheres (2-3 mm and 3-4 mm) and expanded glass (2-3 mm) as reinforcements, and ZL111 aluminum alloy as matrix. The functionally graded aluminum matrix syntactic foams (FG-SFs) were obtained by superimposing two uniform aluminum matrix syntactic foams. Quasi-static compression tests were performed. The plateau stress of FG-SFs containing only hollow spheres decreased slightly with increasing volume fraction of SF containing 3-4 mm hollow spheres. The FG-SFs containing 2-3 mm hollow spheres and 2-3 mm expanded glass showed the highest plateau stress. The energy absorption behavior of all samples fluctuated in a small range. The initial position of shear band depended on the volume fraction of uniform aluminum matrix syntactic foams, reinforcement type and size. The cracks always appeared first in the uniform aluminum matrix syntactic foams containing expanded glass.
Preparation and Properties of Formic Acid Intercalated Mg-Al Layered Double Hydroxides Deicing Additive
Authors: Yu Jian You , Han Xiao Bin , He Peng , Wang Zi Peng , Yu Jian Ying
Published: June 2021

Formic acid intercalated Mg-Al layered double hydroxide (Mg-Al Fo-LDH) was prepared by calcination reduction intercalation assembly technology. The structure of the deicing additive was characterized by fourier transform infrared (FTIR) and X-ray diffraction (XRD). The freezing point of aqueous solution with different quality of deicing additive and the surface freezing point and adhesion of asphalt mixture were tested. The results show that formic acid ion has been intercalated into the interlayer of Mg-Al layered double hydroxide by FTIR and XRD patterns. The freezing point of 5wt% Mg-Al Fo-LDH aqueous solution reaches -9.32 °C, while the surface freezing point of the asphalt mixture mixed with 5wt% Mg-Al Fo-LDH is -6.5°C. At -8 °C, the adhesion force of the surface ice layer is 78.4N, and after the asphalt mixture is soaked in water, the surface freezing point and adhesion force of the ice layer do not change.
Enhancement Mode GaN-FETs in Extreme Temperature Conditions, Part II: Dynamic Parasitic Parameters
Authors: Duraij Martijn S. , Xiao Yudi , Zsurzsan Gabriel , Zang Zhe
Published: June 2021

Parasitic components in eGaN-FETs impact the dynamic performance of switching stages. The capacitances seen, primarily on the output characteristics, of these devices are a main contributor towards switching losses and therefor converter efficiency. Additionally, the threshold voltage of the device has an impact towards the switching speed and therefore the efficiency of a power stage. This study shows the impact of extreme temperatures towards the parasitics that impact the switching behaviour of a power stage. A literature research is conducted exploring the various mechanisms and temperature dependancies, which are then related towards transient operations of eGaN-FETs. A device was chosen to perform measurements on output-, reverse transfer capacitance and threshold voltage while increasing temperature from 100°C op to 225°C. The presented results show a large impact of temperature in these parasisic elements that show that high temperature switch-mode power converters need additional design work to ensure switching performance and lifetime.
Alternative Setup for Long-Duration Low-Duty-Cycle 600°C Ambient Testing of SiC Integrated Circuits
Authors: Izadnegahdar Alain , Booth Stephanie L. , Spry David J. , Neudeck Philip G.
Published: June 2021

A scalable, compact oven testbed system for simultaneously evaluating a multitude of high temperature integrated circuits (ICs) for prolonged operating times of up to 600 °C has been prototyped. The new testbed system enables long-duration high temperature testing in sufficient statistical quantities consistent with standard aerospace electronics engineering standards. This setup is comprised of multiple compact ovens housing chips or packages mounted to ceramic circuit boards. Each oven is a compact 15.2 cm length by 15.2 cm width by 12.7 cm depth with a maximum 400 Watts of heating power. The custom-made silicon oxide ceramic heating block inside each oven is based on a 3D printed design adapted for the easy insertion of the IC device under test (DUT). This innovative design provides the quick insertion of ICs with or without a ceramic package into a 600 °C environment by utilizing a movable 11.43 cm long ceramic substrate with electrical traces extending from the oven hot zone to external standard plastic-based board connectors. Another key oven design feature is the minimization of the DUT exposure to electromagnetic interference (EMI) by utilizing a filtered DC power source to reduce heating element noise. Additionally, the ovens can be configured in a parallel arrangement allowing global data monitoring over a single industrial RS422 serial port. This feature is important for scaling up to test multiple ICs semi-simultaneously. A USB serial port is provided to independently control the operating parameters of each oven such as the oven target temperature and oven ramp rate. The oven temperature can reach up to 600 °C with a confirmed +/− 4 °C maximum deviation across the test zone region. The ramp rate can be programmed from 1 °C/minute up to 10 °C/minute. Furthermore, a programmable switchboard is used to interface with the DUT. This switchboard comprises a National Instruments Peripheral Component Interconnect eXtension for Instrumentation (NI PXI) system and a breakout board to send and receive power, analog or digital test signals. By using this unique oven testbed system, a variety of ICs can now be tested in parallel using the same test components configured for a diverse set of requirements.
Low Loss LTCC Ag System for 5G Applications
Authors: Tormey Ellen , Ma Chao , Maloney John , Smith Bradford , Sridharan Sid , Yang Yi
Published: June 2021

Low dielectric constant/low loss LTCC materials have drawn much attention with the emergence of 5G wireless telecommunications. LTCC offers unique properties in the millimeter wave frequency range. The low dielectric constant and dielectric loss enable low latency devices with enhanced performance. To meet the market demands of higher performance and lower cost, Ferro has developed a new M7 LTCC/Ag cofireable system suitable for antenna in 5G and other high frequency applications. M7 LTCC ceramic green tape and cofireable Ag conductors have been developed and tested. Properties of the LTCC/Ag system are included herein including high frequency dielectric properties.
Clinical Implications of Landing Distance on Landing Error Scoring System Scores
Authors: Hanzlíková Ivana , Hébert-Losier Kim
Published: June 2021

Context

The Landing Error Scoring System (LESS) screens for risk of noncontact anterior cruciate ligament injury. The LESS requires individuals to jump forward from a 30-cm box to a distance of 50% of their body height. However, different landing distances have been cited in the scientific literature.

Objective

To examine whether landing distance influences LESS outcomes.

Design

Cross-sectional study.

Setting

Laboratory.

Participants or Other Participants

Seventy young active individuals (34 males, 36 females).

Intervention(s)

Participants performed 3 × 30-cm jump-landing tasks under 2 landing conditions in randomized order: (1) 50% of body height (d50%), (2) self-selected distance (dss).

Main Outcome Measure(s)

Mean LESS scores, proportions of individuals categorized at high (LESS: ≥ 5 errors) and low (LESS: < 5 errors) injury risk, and landing distances were compared between conditions using generalized estimating equations. Consistency of risk categorization was examined using odds ratios (ORs) and McNemar tests. McNemar and Wilcoxon signed rank tests were used to compare the occurrence of specific LESS errors.

Results

Participants landed closer to the box under the dss condition (difference = −23.28 [95% CI = −20.73, −25.81]%, P < .001). Group mean LESS scores (difference = −0.01 [95% CI = −0.59, 0.57] error, P = .969) and risk categorization (OR = 0.94 [95% CI = 0.47, 1.88], P = .859) were similar between conditions. However, individual-level risk categorization was inconsistent in 33% of participants, as was the occurrence of specific errors.

Conclusions

Using dss during the LESS might lead to different LESS errors and risk categorizations at an individual level than using d50%. Given that individual LESS scores are of primary interest in clinical and sport settings and the injury-risk threshold has not been validated for dss, we recommend use of the original LESS protocol. When only group mean LESS scores or proportions of at-risk individuals are of interest, using dss is feasible to facilitate the testing of large cohorts.
A Clinical and Neurophysiological Analysis of Idiopathic Carpal Tunnel Syndrome with Respect to Gender and Occupation
Authors: Mathew Asha Elizabeth , John Thomas
Published: June 2021

Background:

Carpal tunnel syndrome (CTS) predominantly affects women. Previous studies observed more intense symptoms among women without a corresponding increase in disease severity and attributed it to reporting bias. In this study, we examined whether women are inherently more vulnerable to work related median nerve dysfunction at wrist and whether reported CTS symptoms among women correspond to the degree of median neuropathy at wrist.

Methods:

A cross-sectional study was designed for outpatients (aged 25-59 years) diagnosed with CTS. Occupational categorisation was done based on the analysis of their individual job tasks. Symptom severity (Boston Symptom Severity Scale – SSS), functional disability (Boston Functional Status Scale - FSS), and clinical (Hi – Ob scale) and neurophysiological severity (NCS grade) were determined, compared among occupational groups and were statistically analysed.

Results:

A total of 454 patients (348 women and 106 men; F: M ratio 3.28:1) were included. Among them, 191 were housewives. Female manual workers and housewives reported significantly more intense symptoms with a corresponding increase in clinical and electrophysiological severity (p < 0.001) when compared to female non-manual workers. However, no significant difference in symptoms, clinical or neurophysiological severity was found between male non-manual and manual workers. Among manual workers, women were more symptomatic than men, but clinical and neurophysiological severities were significantly higher only in the older age groups.

Conclusion:

The differential vulnerability of the female population to hand-intensive work predisposes them to severe median nerve dysfunction at wrist with proportionately higher CTS symptoms. Therefore, working women need focussed attention for remedial measures.