bluuebunny/crossref_metadata_2025 huggingface dataset:
Research and analysis of coupling coordination degree between tourism industry and regional economy in Wuhu City
Authors: Guanghong Li , Yuan Hu
Published: September 2021

Taking Wuhu City of Anhui Province as an example, this paper constructs two evaluation index systems of tourism industry and regional economic development respectively, and studies the coupling coordination situation and influencing factors of Wuhu City from 2015 to 2019 by using the coupling coordination degree model. The research shows that the comprehensive development level of Wuhu tourism industry and regional economy system has been steadily improved year by year in the past five years. Coupling degree C showed an up-down trend, but was generally at a high level. The comprehensive development level T of the two systems is also in an increasing trend. By 2019, the coupling coordination degree of the tourism-industry system in Wuhu has been upgraded from good coordination to high quality coordination. In the future development process, Wuhu City should continue to promote GDP growth on the basis of the current good development situation, and realize the win-win situation between tourism and regional economic development.
Grey Prediction Analysis on the Scale of Cross-Border E-Commerce Retail Import Transaction in Hainan
Authors: Nana Chen , Zhixia He
Published: September 2021

Combined with the policy of Hainan free trade port, the advantages of cross-border e-commerce enable the retail import cross-border e-commerce of Hainan free trade port develop rapidly, but Hainan cross-border e-commerce started late, and the data is very limited, so there is almost no reference econometric model. Therefore, this paper used the grey prediction GM (1,1) model to make a short-term prediction analysis of Hainan cross-border e-commerce retail import transaction scale, and used the residual correction model to improve the prediction accuracy, hoping to provide data reference and relevant policy basis for subsequent researchers and managers by analyzing the results in many aspects.
Retail coffee business analysis and industry development research based on Starbucks business model
Authors: Cao Jidi , Qiu Rui
Published: September 2021

As retailing is the customer-based business and easy to observe, standing in this area will be a good view to see the wisdom of business management to change the world. After choosing retail coffee industry as topic, by which Starbucks represented, we will have two major contents to see the knowledge and the insight of business management and industry development research based on Starbucks business model. They are project selection and analysis of Starbucks involving industry development. The Starbucks business model analysis involves product management, customer relationship management, culture and brand management, and ethical marketing and corporate social responsibility. There are still some risks imbedded in the business model. Risks should be estimated and evaluated in advance, whilst project managers need to follow risk mitigation strategies.
Research on Identifying the Risk of Returning to Poverty from Poverty-alleviation Households1 and Industrial Development in Liangshan Prefecture, China
Authors: Ouyang Chi
Published: September 2021

With the victory of China’s fight against poverty in 2020, the focus of poverty alleviation will shift to prevent poverty reinstatement. With the help of the survey data of 676 poverty-alleviation households in Liangshan Prefecture, this paper identifies the poverty-return risk of poverty-alleviation households and further analyzes its related influence mechanism. The results found that most of the poverty-alleviation households have a low risk of returning to poverty. The impact mechanism shows that the village hardening road compliance status, endogenous development motivation, county per capita GDP, and the proportion of wage income are negatively correlated with the risk of poverty-returning households in Liangshan prefecture; however, this effect has group heterogeneity and is more conducive to reducing the poverty-return risk for those with higher risk of returning to poverty. The number of people with disabilities and the number of people receiving subsistence allowances in the family are positively correlated with the poverty-return risk. And put forward suggestions to prevent poverty return based on industrial development.
Dilemma and Breakthrough of Intergovernmental Cooperation in Ecological Environmental Protection Management
Authors: Shunyu Wang
Published: September 2021

With the development of economy, the attention of ecological environment is increasing day by day, and the ecological environment has its special integrity, which makes the local governments cooperate in governance. Local governments for environmental protection industry and environmental division and governance program differences and local responsibilities and other issues, environmental governance intergovernmental cooperation is facing difficulties. Through the establishment of shared interests, strengthening incentives, changing models to create a new inter-governmental governance path, mining suitable for China’s current development of inter-governmental cooperation environmental governance path, to promote the benign development of environmental protection industry governance advice.
Response Surface Methodology of Alcohol Production from TWR Sugar using Saccharomyces cerevisiae TISTR 5339
Authors: Timyamprasert Athitan , Vairojanawong Thanit , Teeravet Siritorn
Published: September 2021

The aim of this research was to develop technique to produce alcohol from Thai white rice (TWR) using Saccharomyces cerevisiae TISTR 5339. TWR sugar was produced from TWR with Amylomyces rouxii TISTR 3182. Response surface methodology (RSM) was applied for investigating the experimental design for production the alcohol. There were 20 experiments involving the three investigated variables of Saccharomyces cerevisiae TISTR 5339 to amount of TWR sugar ratio, concentration of TWR sugar (% Brix) and retention time of fermentation that were studied on alcohol to optimize the condition for production the alcohol. Design of experiment was performed by application of 5-level-3-factors central composite design in order to study the optimum condition for production the alcohol. The investigated results showed that the optimum condition was 4.0 ml of Saccharomyces cerevisiae TISTR 5339 amount to 100 ml of TWR sugar amount, 20%Brix (concentration of TWR sugar) and 7 days of fermentation time.
Evaluation of vernacular landscape attraction for traditional village tourism: A case study of Yongfeng Village in Lanzhou
Authors: Yang Zhi-wei , Chen Jihuan , Duan Jia-yuan , Liu Ben-teng
Published: September 2021

In the context of rural revitalization, the benign development of traditional village tourism is of great significance to the implementation of Rural Revitalization Strategy in China. Taking Yongfeng Village in Lanzhou as the research object, this paper discusses the evaluation method of vernacular landscape attraction. Through the research on the internal and external environment and historical culture of Yongfeng village, this paper constructed the rural landscape attraction system and evaluation index. With the help of the effective data of the questionnaire survey, this paper made an empirical calculation of the rural landscape attraction intensity of Yongfeng Village by using the methods of AHP and factor analysis. The results show that: (1) the protection and rational use of historical and cultural resources is the core content to improve the attractiveness of rural tourism landscape; (3) the internal space is the connotation externalization of the attraction of rural landscape, Renovating the historical built-up environment is the material basis for attracting tourists’ in-depth experience. Therefore, the effective way to enhance the attraction is to activate and integrate the material and non-material rural landscape resources of traditional villages.
High-quality Development Paths of Manufacturing Industry Based on Industrial Convergence
Authors: Liang Yongkang , Luo Xiaoqing
Published: September 2021

Industrial convergence is the key to achieving high-quality development of manufacturing industry. Based on the analysis of the development situation and convergence level of China’s manufacturing and producer service industry, this paper proposed four paths for the high-quality development of manufacturing from the perspective of industrial convergence: the convergence of research and design factor, the convergence of information technology factor, manufacturing servitization, and service-oriented reverse manufacturing. The conclusion provided some theoretical guidance for the development of manufacturing industry.
Optimization of onion Juice inhibiting white-blush in fresh-cutcarrots by response surface methodology
Authors: Lu Jiani , Jiang Xiaoning
Published: September 2021

The effect of onion juice on the whitening of fresh-cut carrots during storage was explored to optimize the processing technology of fresh-cut carrots. Using fresh carrot and onion as raw materials and whiteness value as reference index, the process parameters were optimized by response surface methodology (RSM) based on single factor experiment, and the physiological and biochemical indexes were determined. Results showed that the process conditions optimized by response surface processing of fresh-cut carrot onion were as follows: the concentration of the onion juice for 75%, soaking time for 15 min, spin-drying time for 60s. Under this condition, for the fresh-cut carrot, whiteness value theoretical value was 30.51, and the actual whiteness value was 31.26±0.5. After verification, the model was established and the fit worked well. The quality of fresh-cut carrots treated with onion juice was better. This study laid a scientific foundation for the inhibition of whitening of fresh-cut carrot.
Preparation and properties of injectable hemostatic and wound healing promoting hydrogel
Authors: Tang Keru
Published: September 2021

In daily life, people are susceptible to injuries from the outside world. Bleeding wounds and long-term non-healing bring a lot of trouble to the lives of the injured. As a result, it developed a class of wound healing materials based on gelatin combined with calcium ions. By exploring the different behaviors of gelatin aqueous solution at different temperatures and concentrations to form gels, we determined the concentration of the prepared gelatin. Next, calcium-containing substances were added to the gelatin. Through discussing the way and concentration of two different forms of calcium source eggshell and calcium gluconate added to gelatin, the optimal ratio of calcium source to gelatin was determined. Finally, an injectable gelatin hydrogel hemostatic material which is convenient for coating was prepared.
Specific measures to response pandemic of COVID-19 in China: a systematic review
Authors: Chen Ruoyu , Gao Renfei , Huang Xinyi , Lei Qingqing
Published: September 2021

Contemporarily, the novel Coronavirus (SARS-CoV-2, abbreviation for COVID-19) has raged around the world in a short time, which attracts the attention of countries around the world. This virus is spreading fast with a considerable impact, posing a huge threat to global public health. The challenges COVID-19 presented require a robust response. As the world's best country in epidemic control, China has done a lot of control measures. These measures include laboratory confirmation, social distancing and vaccine. Evidences have proved that these measures taken by China have effectively reduced the incidence and mortality of COVID-19 in China. This article will provide a systematic review of these control measures in China, in the hope of providing information for global infectious disease control.
Impact of DIC biases on the selection process of a unique test for anisotropic plasticity characterization
Authors: Thoby Jean-David , Fourest Thomas , Langrand Bertrand , Notta-Cuvier Delphine , Markiewicz Eric
Published: September 2021

The exploitation of field measurements with inverse identification methods may reduce the number of required tests to characterize complex material constitutive models, provided that the generated stress field is sensitive enough to the targeted material parameters. For anisotropic elastoplastic material, the objective is to generate various stress states in the specimen through a single test. In this study, the effect of Digital Image Correlation measurement biases on the selection of the most suitable specimen geometry for characterisation of a complex anisotropic plasticity criterion using a unique uniaxial tensile test is investigated. To this aim, finite element (FE) based synthetic images are generated and DIC is used on these images. The biases in DIC measurement result in biased stress states that may cause errors in identification results.
A Laboratory-Scale Instrumented Forging Hammer as an Intermediate Strain Rate Testing Device
Authors: Agirre Julen , Erice Borja , Abedul David , Saenz de Argandoña Eneko , Otegi Nagore , Galdos Lander
Published: September 2021

Mechanical characterisation of metallic materials at intermediate strain rates is essential to calibrate and validate computational models for industrial applications such as high-speed forming processes i.e. hammer forging, blanking, forming, etc. The most common devices that perform medium to high loading rate experiments are the servo-hydraulic universal testing machines and Split Hopkinson bar systems. Here we analyse the possibility of employing an in-house designed and constructed DirectImpact Drop Hammer (DIDH) for material mechanical characterisation at medium strain rates, ranging from 100 to 300 s-1. To show the suitability of the DIDH for mechanical characterisation, uniaxial compression experiments on S235JR structural steel are conducted and compared with finite element (FE) simulations performed with an elasticthermoviscoplastic material model previously calibrated with Split Hopkinson Pressure Bar (SHPB) tests.
Mechanical characterization of 3D printed concrete subjected to dynamic loading
Authors: Napolitano Rosanna , Menna Costantino , Forni Daniele , Asprone Domenico , Cadoni Ezio
Published: September 2021

In concrete structures realized by digital fabrication techniques, such as 3D concrete printing, under severe dynamic loadings (e.g. earthquakes and impact loads), the strength at the bond interfaces between layers is weak. Since these contact zones, also referred as cold joint, could potentially compromise the structural stability and also the durability of printed elements, their behaviour under high dynamic loads is fundamental to investigate. An experimental program on 3D printed concrete elements varying the waiting time, through medium and high strain-rate tensile tests is running, with a Hydro-Pneumatic Machine and a modified Hopkinson tensile bar respectively. The results of dynamic tensile tests at three different strain rates (10-5, 50 and 200 s-1) on 3D printed cementitious elements for waiting times of 0min, 10min and 30 min have been presented, in terms of Dynamic increase factors DIF versus strain rate, showing a behaviour highly strain-rate sensitive, recording an increase in tensile strength DIF up to 7.6 in the case of high strain-rate and waiting time of 30 min. The results exhibited a decrease in the dynamic interface tensile strength with the waiting time up to over 90% for a medium strain-rate and over 20% for a high strain-rate.
A new method for determination of plastic deformation properties at high strain rate and its modelling
Authors: Fang Xiangfan
Published: September 2021

The determination of material properties under high speed loading is a challenge. The system ringing in a conventional servo-hydraulic tensile testing machine deteriorates the quality of force measurement, which makes a precise determination of yield locus, strain hardening and fracture strain difficult. In this work, the system ringing effect of the entire tensile testing system were analyzed. It was determined that the ringing of the system is location and geometry dependent. A new type of tensile sample has been developed. Beside of the usual major plastic deformation area, it has an additional elastic area, within which a locally restricted secondary minor plastic deformation takes place. This very small plastic deformation absorbs the elastic vibrations in this area. Therefore, the deformation forces can be measured by strain gauge without any ringing effect. The plastic deformation behavior of materials can be determined for a wide range of strain rate of 0.0001 - 1000 /s exactly. To explain the functionality and the physical background of the new sample, based on the equations for one-dimensional stress waves and theory of the stress wave attenuation due to dislocation motions, a simplified beam model with analytical formulations could be established und programmed in MATLAB. Verifications show a good prediction of sample geometry using this simplified model.
Experimental analysis of high velocity impacts of composite fragments on aluminium plates
Authors: López-Puente Jorge , Pernas-Sánchez Jesús , Artero-Guerrero José Alfonso , Varas David , Múgica Joseba , Lopes Claudio S. , Martino Esteban , Votsios Vasilis
Published: September 2021

The improvement of engines is one of the ways to diminish the fuel consumption in civil aircrafts, and Open Rotors engines are one of the best promises in order to achieve a sensible efficiency increment. These engines have large composite blades that could, in the event of failure, impact against the fuselage, totally or partially. In this case, composite fragments could behave as impactors. In order to design fuselages for this event and adopt these new engines in the future, it is necessary to understand the impact behaviour of a composite fragment against a deformable structure. To this end, unidirectional and woven composites fragments were impacted at high velocity (up to 150 m/s) against aluminium panels at different impact velocities. The composite fragments were made using AS4/8552 (UD) and AGP-193PW (woven) prepregs manufactured by Hexcel Composites, both using AS4 fibres and 8552 epoxy matrix. High speed video cameras were used to record the impact process and to measure both the impact and the residual velocity and hence the energy absorbed.
Plate-impact-driven ring expansion test (PIDRET) for dynamic fragmentation
Authors: Gant Fanny , Seisson Gabriel , Longère Patrice , El Maï Skander , Zinszner Jean-Luc
Published: September 2021

A new experimental set-up mounted at the muzzle of a singlestage gas gun has been designed in order to study the fragmentation of metallic rings under dynamic radial expansion. This concept takes advantage of the quasi-incompressibility of HDPE whose radial flow under plate impact-like loading is used to apply a pressure boundary condition at the ring’s inner surface. For the experimental configurations considered in the present work, the average strain rate in the ring reaches values close to 104 s-1. The repeatability and the reliability of the experiments are verified for rings made of steel and aluminium.
Local Shock Properties Measurement Using Time-Resolved Raman Spectroscopy
Authors: Dhiman Abhijeet , Lewis Nolan S. , Olokun Ayotomi , Tomar Vikas
Published: September 2021

In this article, the dynamic response of a heterogeneous microstructure of polymer bonded composite was analyzed to a short duration shock pulse. The composite microstructure studied is a polymerbonded sugar (PBS) with single-crystal sucrose embedded inside the polydimethylsiloxane binder. The shock pulse was created by the impact of the aluminum disk at high speeds using a laser-based projectile launch system. The mechanical response on the microscale domain was measured using ultrafast time-resolved Raman spectroscopy. The in-situ analysis of the change in Raman spectra from PBS during shock compression was captured in the time domain using a streak camera. The results show a steeply rising shock front after the impact where the shock pressure rise time was estimated from the time-resolved Raman spectra. The viscoplastic behavior in the local microscale domain was characterized by quantifying effective shock viscosity measured in the vicinity of the crystal-binder interface.
Experimental Investigations of 3D Woven Layer to-Layer Carbon/Epoxy Composites at Different Strain Rates
Authors: Yoo Sanghyun , Dahale Monali , Neale Geoffrey , Toso Nathalie , Catalanotti Giuseppe , McIlhagger Alistair , Archer Edward , Harkin-Jones Eileen , Voggenreiter Heinz
Published: September 2021

This paper reports experimental investigations of 3D woven carbon/epoxy composites on quasi-static and dynamic tensile properties in the longitudinal (warp) and transverse (weft) directions. Firstly, quasi-static tests were conducted to determine a baseline tensile strength and to find out the adequate specimen geometry required for dynamic testing. Secondly, dynamic tensile properties at intermediate strain rates (nominal strain rates from 0.1 to 200 s-1) were investigated alongside the corresponding failure mechanisms. Detailed information on failure patterns is obtained with strain field measurements from Digital Image Correlation (DIC) and CT scans. The results show that 3D woven composites are strain rate insensitive and the crack initiation is located near weft yarns and binding interlacement points due to the presence of resin rich areas.
Characterization of mechanical behaviour of aluminum powders under fast dynamic conditions
Authors: Delloro Francesco , Durand Hugo , Lacourt Laurent , Teissedre Jean-Christophe , Thorel Alain , Lahouij Imène , Lavaud François , Clausse Xavier
Published: September 2021

Cold spray is a process belonging to the thermal spray family, characterized by relatively low temperatures and high particle velocities. Upon impact, particles undergo large plastic deformation at solid state in dynamic regime up to 109 s-1. The knowledge of powder behaviour in such conditions is essential to catch key phenomena in cold spray and a necessary step for a correct process modelling. However, little is known on mechanical behaviour of feed-stock powders when submitted to cold spray conditions. In this study, an approach focused on single particles combining laser shock induced impact, namely LASHPOL (LAser SHock POwder Launcher), and quasi-static compression was therefore developed. This method was applied in this study on spherical Aluminium powders but can work with any other powder material. The mechanical behaviour of powders was characterized and used to fit the parameters of Johnson-Cook constitutive model, by means of finite element inverse method. The combination of static and dynamic tests resulted in an original characterization of powder, which revealed having a different mechanical behaviour than the corresponding bulk material.
Ballistic impact on concrete slabs: An experimental and numerical study
Authors: Kristoffersen Martin , Toreskås Oda Lunde , Dey Sumita , Børvik Tore
Published: September 2021

The ballistic perforation resistance of 50 mm thick concrete slabs impacted by 20 mm diameter ogive-nose steel projectiles is investigated experimentally and numerically. Three commercially produced concretes with nominal unconfined compressive strengths of 35, 75 and 110 MPa were used to cast material test specimens and slabs. After curing, ballistic impact tests were carried out to determine the ballistic limit curve and velocity for each slab quality. Material tests instrumented with digital image correlation (DIC) were conducted along the ballistic impact tests. DIC measurements were used to establish engineering stress-strain curves for calibration of a modified version of the Holmquist-Johnson-Cook concrete model. Finite element simulations of the impact tests gave good conservative predictions.
Experimental analysis and modelling of dynamic deformation and failure behaviour of steel
Authors: Zeng Chongyang , Fang Xiangfan
Published: September 2021

New specimen geometries with various stress states are designed and applied for dynamic loading tests. Oscillation-free force is measured during multiaxial loading tests in the strain range of 10-4 – 103 s-1. The deformation and local strain fields of specimens have been measured using high-speed camera and evaluated by digital image correlation (DIC) techniques. It is found that the strain rate effects on fracture strain are stressstate dependent. To model the material plasticity and ductile fracture behaviour during dynamic tests, an extended damage mechanics model (eMBW model) is used. In this work, the model is enhanced and implemented into LS-DYNA. To cover the strain rate effects on plasticity at a large strain rate range, a modified Johnson–Cook-type rate-dependency and exponential temperature-dependency are used. In addition, the influences of both stress state and strain rate on fracture locus are considered. The enhanced damage mechanics model successfully predicts the deformation and fracture behaviour of the investigated steel under dynamic multiaxial loading.
Effect of Grain Level Anisotropy on Numerical Rock Fracture Behaviour under Dynamic Loading
Authors: Saksala Timo
Published: September 2021

The effect of rock crystal anisotropy is tested in numerical simulation of rock fracture at the laboratory sample level of scale. For this end, a numerical model based on the embedded discontinuity finite element method is applied here in simulations of uniaxial tension test on granitic rock. The rock material, consisting of Quartz (trigonal), Feldspar (triclinic) and Biotite (taken hexagonal here), is described as a linear elastic (up to fracture) heterogeneous and anisotropic material, which fails upon reaching the tensile strength of the individual constituent minerals. In the simulations of uniaxial tension test at two different levels of strain rate, the effect of averaged versus anisotropic elastic constants is tested. The results demonstrate that the effect of anisotropy is stronger at low strain rates (0.25 s-1 here), resulting in macrocrack planes at different locations for the isotropic and anisotropic material descriptions, while at higher rates (25 s-1 here) its notable effects disappear in the details of multiple macrocracks.
The research of destruction of functionally-graded materials subjected to impact loading
Authors: Orlov Maxim Yu. , Glazyrin Viktor , Orlova Yulia
Published: September 2021

A numerical analysis on impact response of multilayer plates and plates with a gradient substrate against steel projectile perforation was made. The shear strength was varied in the substrate within a certain range. The behavior of bodies is modeled by an elastic-plastic, porous, compressible medium, taking into account shock-wave phenomena and fragmentary fracture of materials. A numerical lagrangian method with modified node splitting algorithms was used. Good agreement between the computed and experimental results was obtained. During perforation, pattern of destruction of all plates has been investigated. The results show impact resistance of plates with a gradient substrate was greater than the homogeneous steel one, but less than multilayer ones. However, the impact resistance of multilayer plates is explained by the pinching effect of the layers.
Numerical investigation on the effect of specimen gripping arrangement on dynamic shear characterization using Torsion Split Hopkinson Bar
Authors: Ramagiri Bhaskar , Yerramalli Chandra Sekher
Published: September 2021

Torsion Split Hopkinson Bar (TSHB) is widely used in the dynamic shear characterization of material under pure shear loading. In TSHB, tubular specimens with either circular or hexagonal flanges are used. The specimens with circular flanges are generally bonded using adhesive to the incident and transmission bars. The specimens with hexagonal flanges are gripped into the hexagonal holders that are fixed onto incident and transmission bars. In the current study, numerical simulations are carried out to see the effect of gripping arrangements on the dynamic shear characterization quality. Numerical experiments with three gripping configurations are studied—the first gripping configuration with a direct bond (numerically-tie) between specimen and bars. The second configuration with the specimen gripped by hexagonal holders fixed to bars. The third configuration with specimen directly gripped into the incident and transmission bars having hexagonal slots.
Experimental investigation of strain rate dependent damage mechanisms in DP1000 automotive steel
Authors: Chandran Sarath , Verleysen Patricia
Published: September 2021

Present study aims to investigate the effect of stress state and loading rates on the damage mechanisms in a DP1000 steel using a welldesigned series of experiments. A specimen family comprising of central hole, in-plane shear and plane strain samples is applied to characterise damage under well-controlled stress states. The optimization of the specimen geometries is achieved using finite element simulations. To assess the influence of strain rate, quasi-static, intermediate and dynamic tests are performed on the designed samples. Local strain fields are obtained by digital image correlation. After testing, scanning electron microscopy is employed to systematically analyse the micromechanisms driving the damage in the investigated material. The underlying damage mechanisms are ferrite-martensite interphase debonding, martensite cracking and debonding at ferrite-ferrite grain boundaries. Stress state and strain rate are found to have distinct influences on triggering the underlying damage mechanisms.
Shock-reshock of zirconium to explore the effect of microstructure on the alpha-omega phase transformation
Authors: Morrow Benjamin M. , Escobedo-Diaz Juan P. , Jones David R. , Trujillo Carl P. , Martinez Daniel T. , Rigg Paulo A. , Harvey Cayla R. , Gray III George T. , Cerreta Ellen K.
Published: September 2021

Phase transformations play an important role in the mechanical behavior of materials subjected to extreme loading conditions. A series of shock-reshock experiments were fielded to determine whether the phase transitions in materials are significantly enhanced or inhibited by preexisting microstructural features. Polycrystalline zirconium samples were shock loaded using gas-gun plate impact and soft recovered to examine microstructure using electron backscatter diffraction (EBSD). Drive conditions were varied to study the (hcp) alpha to (hexagonal) omega solidsolid phase transformation. Recovered samples were then subjected to a second shock loading event to determine the change in material behavior as a function of pre-shock microstructure. Crystallography of phase fragments in the final microstructure showed that prior twinning (formed during the shock to a peak stress below the transition threshold) appeared to suppress omega formation/retention after reshock. Conversely, when a material was initially shocked into the omega phase field, retained-omega was not found to have a large impact on subsequent omega formation during reshock. This suggests that nucleation and growth of omega phase are important processes, and the relative activity of nucleation vs. growth processes is modified by a pre-existing substructure. Additionally, orientation relationships reveal a reverse transformation pathway (omega to alpha) dominates the final microstructure, suggesting significant grain growth in the omega phase field is possible even for dynamic timescales.
On the effects of build orientation, strain rate sensitivity and sample thickness on the mechanical behavior of 316l Stainless Steel manufactured by Selective Laser Melting
Authors: Carassus Hugo , Morvan Hervé , Haugou Gregory , Guerin Jean-Dominique , Sadat Tarik , Guerard Sandra , Markiewicz Eric
Published: September 2021

The Additive Layer Manufacturing (ALM) for metallic materials has grown in the past few years. However, this process influences the mechanical properties of the constitutive material and consequently those of the finished product. The influence of the thickness and the building direction of 316L Stainless Steel (SS) specimens produced by Selective Laser Melting (SLM) on the quasi-static mechanical behavior has already been reported. Considering the strain rate effect, it has been only studied for tensile properties of vertical specimens up to 102s–1. The aim of this work is to study the influence of the thickness and the building orientation at higher strain rates up to 101s–1 and up to 103s–1 for vertical specimens. Compared to conventional material, 316L SS SLM achieves equal and even better mechanical properties due to a refinement of the microstructure. Anisotropy is observed at the macroscopic level, which is explained by the microstructure with different shapes, orientation and size of grains. A minimum thickness of 0.75mm is recommended to recover the mechanical properties of the conventional 316L SS. A positive strain rate sensitivity is observed in every case. The material anisotropy and the thickness variation do not affect the strain rate sensitivity.
Size Dependence and Dynamic Properties of Adobe Masonry Bricks tested at high strain rates
Authors: Li Piani T. , Weerheijm J. , Peroni M. , Sluys L.J.
Published: September 2021

Masonry is a construction technique which typically reacts in compression. Characterization of its material properties in compression is thus of paramount importance. This especially counts for adobe bricks because their material properties are still unknown to a large extent. This traditional masonry, made of locally available soil and fibres, is spread in areas currently involved in military conflicts, where also European forces operate. Therefore, not only its static properties in compression, but even more the dynamic strength is a relevant parameter. Laboratory characterization of material properties still pose several challenges, among which so-called size dependence is one of the most controversial topics. This entails the possible variation of material properties values from tests on specimens of different size and shape. Several factors may concur to its determination and a well-founded theory does not exist yet. This counts for statics and even more in dynamics. Addressing the properties in compression of bricks at high strain rates is rare, namely no studies of size dependence on masonry bricks in dynamic regimes are published. Lately, a series of experimental campaigns were conducted by the authors at the Joint Research Centre of the European Commission. In these campaigns, a series of compression tests were performed on several types of adobe bricks. Different soil mixtures were used to produce cylindrical samples of different sizes. Compressive tests from 2e-5 s-1 to 10 s-1 and 100 s-2 were executed using hydraulic machines as well as split Hopkinson bars. Next, the static as well as the dynamic material properties as calculated from tests on specimens of different sizes and material compositions have been qualitatively and quantitatively compared and interpreted. In this paper, the experimental program is presented, next the material properties in strength and ductility as well as the dynamic increase factors are investigated.
Deformation and fracture properties of pure ice through impact indentation testing
Authors: Nakao Yuki , Yamada Hiroyuki , Ogasawara Nagahisa
Published: September 2021

The deformation and fracture properties of ice have attracted considerable research interest. The tip shape of an object that comes into contact with the ice may affect the fracture phenomenon of ice, but these mechanisms have not been elucidated. In previous study, we experimentally showed that the shape of the indenter has a significant effect on pure ice deformation and fracture properties by quasi-static indentation testing. In this study, we focus on the impact fracture of pure ice to clarify the effect of strain rate on deformation and fracture phenomena. The impact indentation test was conducted using direct impact Hopkinson bar method, and a spherical indenter with a diameter of 9 mm was attached to the tip of the striking bar. The indentation rate was approximately 2.3 m/s, and the test temperature was approximately -10°C. It was clear that the maximum load of the load–displacement relationship was larger than that of the quasi-static indentation testing. This tendency was qualitatively consistent with the compressive strength of the uniaxial compression testing.
Dynamic deformation and fracturing properties of concrete under biaxial confinements
Authors: Wang Huachuan , Liu Kai , Zhang Qianbing
Published: September 2021

The study of deformation and fracturing properties of concrete is essential to understand failure mechanisms of concrete material, especially under extreme and complex loading conditions, e.g. high strain rates and multiple confinements. In this study, dynamic deformation and fracturing behaviour of ordinary concrete under biaxial confinements are investigated by using a triaxial Hopkinson bar system, three-dimensional digital image correlation, and synchrotron X-ray computed tomography techniques. Results show that compressive strain localisation areas appear around aggregates due to the elastic difference between aggregate and matrix, where accompanied with initiation of interfacial cracks and propagation of main cracks. Transgranular cracks can also be observed in the central of specimen in CT slices due to the effect of strain concentration. In addition, CT slices with distinct properties in various directions indicate the anisotropic fracturing behaviour of concrete due to the effect of biaxial confinements.
Impact Failure of Polycrystalline Diamond Cutters
Authors: Laurence Robin C , Todd Richard I , Siviour Clive R
Published: September 2021

Polycrystalline Diamond (PCD) Cutters are ultra-hard tools used for oil and gas drilling. These tools can fail in the form of spalling due to impact. In this paper, direct impact and quasi-static loading are used to investigate the failure force for leached PCD cutters when loaded at an angle on the edge of their chamfer with a PCD striker or platen. Impact experiments were performed using an impedance match system which ensures the sample is only loaded once; this allows subsequent analysis of the failure surfaces. The failure force at high deformation rate is around 8 kN and at low deformation rate 6.3−+2.3kN. The failure force required for spalling increases with increasing deformation rate. High speed imaging is also used to explore the failure history of the cutters.
Kinetic Energy Penetrator (KEP) impact on confined concrete
Authors: Abdulhamid Hakim , Delabre Kevin , Plassard Fabien , Héreil Pierre , Mespoulet Jérôme , Deconinck Paul
Published: September 2021

Understanding concrete response facing warheads threats is important for both the design of strategic infrastructure protection and the prediction of warhead performances. This ongoing study aims at building a robust approach for the characterisation of concrete behaviour under ballistic impact of Kinetic Energy Penetrator (KEP). A set of tests has been developed and performed to fit the main parameters of the Holmquist Johnson Cook Concrete material model. Highly instrumented tests are conducted to improve the model prediction capability and to identify its limits. After a brief description of the test configuration, the paper focuses on the analysis of an impact test and presents preliminary simulation results.
Osteoblasts Regulate the Expression of ADAMTS and MMPs in Chondrocytes through ERK Signaling Pathway
Authors: Ding Xiao , Xiang Wei , Meng Defeng , Chao Wang , Fei Han , Wang Weishan
Published: September 2021

Objective Degradative enzymes such as matrix metalloproteinase (MMP) and disintegrin metalloproteinase with platelet thrombin-sensitive protein-like motifs (ADAMTS) play a key role
in the development of osteoarthritis (OA). We aimed to investigate the effects of OA subchondral osteoblasts on the expression of ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 in chondrocytes
and the regulation of mitogen-activated protein kinase (MAPK) signaling pathway.

Methods A rat knee OA model was constructed by cutting the anterior cruciate ligament of the knee joints, and normal rat articular cartilage chondrocytes (N-ACC), OA rat articular
cartilage chondrocytes (O-ACC), normal subchondral bone osteoblasts (N-SBO), and OA subchondral bone osteoblasts (O-SBO) were isolated and extracted. The expressions of O-ACC and O-SBO
COL1 and COL2 were detected respectively. Chondrocytes were identified by immunofluorescence of COL2 and toluidine blue staining, and osteoblasts were identified by COL1
immunofluorescence, alkaline phosphatase (ALP), and Alizarin Red staining. Gene expression of COL1, COL2, and aggrecan in normal chondrocytes and OA chondrocytes, and gene expression of
osteoblast ALP and osteocalcin (OCN) were detected by RT-PCR to identify the two chondrocytes and the two osteoblast phenotypes. The constructing N-ACC group, O-ACC group, N-ACC + N-SBO
group, N-ACC + O-SBO group, O-ACC + N-SBO group, O-ACC + O-SBO group, I + N-ACC + O-SBO group, and I + O-ACC + O-SBO group cell cultures, and the expression of ERK, ADAMTS4, ADAMTS5,
MMP-3, MMP-9, and MMP-13 genes in chondrocytes cultured for 0, 24, 48, and 72 h were detected by RT-PCR. The protein expressions of pERK, ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 were
detected by Western blot.

Results

Conclusions
Wie sinnvoll ist die Zweipunktdiskrimination als diagnostisches Mittel bei der Epicondylopathia humeri radialis?
Authors: Börms Kirsten , Richter Michael
Published: September 2021

Die diagnostische Aussagekraft der Zweipunktdiskrimination (ZPD) als Indikator für chronische Krankheitsprozesse (z. B. Complex Regional Pain Syndrome, Chronic Low Back Pain) ist mehrfach untersucht und gilt als belegt. Das Ziel der vorliegenden Arbeit war es, die ZPD als diagnostisches Mittel in der Ellenbogenregion zu untersuchen.

Mithilfe eines Ästhesiometers (Schieblehre) wurde die ZPD im Bereich des lateralen Ellenbogens bei einer Patientengruppe (N = 21) mit der Diagnose Epicondylopathia humeri radialis sowie einer gesunden Kontrollgruppe (N = 40) mit folgender primärer Fragestellung untersucht: Kann die ZPD am Ellenbogen gesunde Proband(inn)en von Proband(inn)en mit Epicondylopathia humeri radialis unterscheiden? Als Basis wurden ZPD-Normwerte anhand der Kontrollgruppe am lateralen Ellenbogen erstellt. In einer vertiefenden Datenanalyse der Patientenpopulation wurden die Daten der Patient(inn)en mit einem akuten (N = 13) mit den Daten der Patient(inn)en mit einem chronischen (N = 8) Zustand verglichen.

Im Ergebnis scheint die ZPD kein geeignetes Diagnostikinstrument zur Differenzierung der Fall- von der Kontrollgruppe sowie von akuten und chronischen Verläufen in der lateralen Ellenbogenregion zu sein.
Lesend Fortbildungspunkte sammeln
Authors: Zalpour Christoff
Published: September 2021

Wer eine Physiotherapiezeitschrift von Thieme abonniert hat, kann damit künftig Fortbildungspunkte sammeln. Regelmäßig wird es sogenannte CPTE-Artikel samt Fragen geben, die man online beantworten kann. Der Artikel erzählt den Weg der Forschungsgruppe, die sich mit Continuing Physiotherapy Education beschäftigt.
1,3-Dipolar [3+3] Cycloaddition of 1,4-Benzodiazepinone-Based Nitrones with α-Halohydroxamates for Diastereoselective Synthesis of Novel d-Edge Heterocycle-Fused 1,4-Benzodiazepinones
Authors: Zhao Hong-Wu , Zhang Heng , Cai Lu-Yu , Tang Zhe , Fan Xiao-Zu , Wu Hui-Hui , Bi Xiao-Fan
Published: September 2021

Promoted by K2CO3 (2.0 equiv), the 1,3-dipolar [3+3] cy­cloaddition between 1, 4-benzodiazepinone-based nitrones and α-halohydroxamates processed smoothly under the mild reaction conditions and delivered structurally novel and complex cis- or trans-configured d-edge heterocycle-fused 1,4-benzodiazepinones in up to >99% isolated yield with >20:1 dr. The relative configuration of the title chemical entities was clearly identified with the use of single-crystal X-ray structure analysis. The reaction mechanism was assumed to interpret the diastereoselective production of the obtained cis- or trans-configured d-edge heterocycle-fused 1,4-benzodiazepinones.
A Baby at All Costs? Exploring the Use and Provision of Unproven Adjuvant Treatments in the Context of IVF
Authors: Jones Georgina L. , Lang Victoria , Hudson Nicky
Published: September 2021

The year 2018 marked 40 years since the birth of Louise Brown, the first baby born as a result of pioneering in vitro fertilization (IVF) treatment. Since then, advances have seen a wide range of reproductive technologies emerge into clinical practice, including adjuvant treatments often referred to as IVF “add-ons.” However, these “optional extras” have faced growing criticism, especially when they have often come at additional financial cost to the patient and have little evidence supporting their efficacy to improve pregnancy or birth rates. Despite this, according to the latest national patient survey by the Human Fertilisation and Embryology Authority, three quarters of patients who had fertility treatment in the United Kingdom in the past two years had at least one type of treatment add-on highlighting the growing demand for these interventions. This article uses a psychosocial perspective to consider the motivations behind patient and clinician behavior along with the wider societal and economic factors that may be impacting upon the increase in the use of adjuvant treatments in fertility clinics more widely. It suggests the reasons fertility patients use unproven “optional extras” are complex, with interpersonal, psychological, and social factors intertwining to generate an increase in the use of IVF add-ons.
More efficient wind turbine blade design inspired by owl wings and feathers
Authors: Kim Meeri
Published: September 2021

Incorporating the cross-section airfoils of an owl’s wing, coupled with the herringbone groove structure of an owl’s feature, leads to better aerodynamic performance.
Combining nanosized elementary building blocks of soft and hard matter to create strong, damage resistant materials
Authors: McConnon Aili
Published: September 2021

Creating strong materials at 325 degrees Celsius using particles in the nanometer range that arrange perfectly in supercrystals via self-assembly
Optimal dispatch of heterogeneous energy complementary system under energy indifference bidding
Authors: Lai Chunyang , Ma Guangwen , Zhang Xinshuo , Chen Shijun , Huang Weibin , Zeng Hong
Published: September 2021

Owing to the influence of uncontrollable factors (e.g., climate), wind and photovoltaic (PV) energy are highly fluctuating and undispatchable, thereby hindering their integration to the grid. To address this issue, complementary systems using hydropower as a regulating energy are gradually emerging. With the development of wind and PV power industries and the electricity spot market, wind and PV power subsidies are being reduced, and the bidding subjects are diverse. It is likely that wind, PV, and hydropower will participate in the market with the same quality and price. Wind–photovoltaic–hydropower complementary systems (WPHCSs) normally aim at minimum wind and PV power curtailment, which do not consider hydropower production aspects. This study considers the effect of complementary operation on hydropower in the context of energy indifference bidding in the future electricity spot market, establishes a comprehensive benefit index system to optimize WPHCS, and proposes a particle swarm optimization algorithm that introduces the dominant solution with an adjustable parameter to solve the maximizing comprehensive benefits of a complementary system model. Control experiments with different loads, storage capacities, inflows, and models were conducted to verify the superiority of the proposed model and to summarize the optimal operation rule of the complementary system. The results show that turbine efficiency is the main factor affecting the results, and the total benefit of the system could be improved by up to 69% comparing with the priority consumption of wind and the PV power model. This paper describes the WPHCS benefits more comprehensively, and the results can be used to improve the benefits of complementary systems.