bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and flow rate improvement of a small aeroengine turbine
Authors: Jiang Z Y , Fan Z L , Qiu M , Yang D W 
Published: April 2021

AbstractThe need of small high thrust-to-weight ratio aeroengine is growing. One way to meet this is higher through flow rate of engine. Higher engine mass flow means higher turbine mass flow. In the paper, a small turbine is designed and then promoted with higher flow rate. First the definition of universal turbine through flow capability is discussed and formulated. Then the design and flow rate promotion process of a turbine is introduced. And three design results are obtained and compared, marked MI, MII, and MIII. Among them, MI is original design result with highest efficiency of 0.8899 but doesn’t meet mass flow requirement. MII and MIII are two retrofitted turbines based on MI both with improved mass flow rate by about 3.40%. Different flow rate improvement methods are implemented for the two turbines. S shape endwall is applied to MII stator shroud and MIII turns down stator blade exit angle a bit. MII has higher efficiency than MIII but through flow capability is in fact lowered. Efficiency decline has been seen in both two redesigned turbines compared to MI. The reason possibly lies in the increased rotor shock loss found by detailed CFD flow analysis. Finally, MII is regarded as the best result of which efficiency is 0.8884.
Study on the influence of hot streak and swirl on the film cooling performance of the leading edge of the guide vane
Authors: ChenXiao  , Wei-lin YI 
Published: April 2021

Abstract
In order to study the impacts of the non-uniform conditions of the combustor exit on the flow loss of the turbine guide blade and the cooling performance of the leading edge film, a hot streak and swirl distribution generation program has been developed to implement the parameterization specification of the non-uniform flow state. In addition, the calculation of this paper is based on GE-E3, the numerical simulation analysis is conducted for the swirl/hot streak of the positive blade on the leading edge of the film cooling guide blade. The results showed that the presence of hot streak increased the non-uniformity of vane heat load and had no effect on vane wall pressure distribution. The presence of swirl changes the pressure distribution on the vane wall, affects the migration form of hot streak in the passage, and reduces the cooling effect of the film cooling on the vane. The temperature at the outlet section of the guide vane is uniform.
Effect of Gradient Layer Number on Microstructure and Property of Laser Deposition TA15/Ti2AlNb Transition Zone
Authors: He Bo , Ying-tong Lin , Yang Guang , Qing-jun Zhou , Xiang-ming Wang 
Published: April 2021

Abstract
3 numerical models of laser deposited TA15/Ti2AlNb gradient composite structure were established to simulate the temperature variation of gradient composite structures with different gradient layers in different regions. Then TA15/Ti2AlNb gradient composite structures with different gradient layers were prepared by laser deposition technology. The microstructure, room-temperature tensile properties and microhardness of the deposited samples were observed by optical microscope, tensile testing machine, scanning electron microscope and microhardness tester. The results showed that as the number of gradient layers increased, the temperature in the deposition process of the transition zone increased, while the microstructure difference in the transition zone decreased gradually. As the number of transition layers increased, the tensile strength decreased, but the elongation after fracture increased. All the fracture locations were in the transition zone, and with the increasing of gradient layers, the fracture location gradually shifted to the Ti2AlNb side. The microhardness of the transition zone increased with the increasing of gradient layers. This study will provide reference for the optimization design of TA15/Ti2AlNb gradient composite structure.
Influence of inlet flow field uniformity on the performance of the nuclear main pump
Authors: Sha Long , Yang Shuhua , Kong Xiangdong , Sun Hui , Pei Lin 
Published: April 2021

Abstract
A test loop system with adjustable spoiler function and visual structure was built in this paper. A PIV test system was adopted to investigate the influence of the uniformity of the inlet flow field on the performance of a nuclear main pump scale model, and the NUMECA software was used to numerically simulate the test cases. The research results show that when the rotation direction of the spoiler blade is opposite to that of the impeller, the greater the deviation of the spoiler blade from the axial angle, the more the pump efficiency and head drop; proper positive pre-rotation will not reduce the pump efficiency, but will increase the pump head; for the same spoiler blade deflection angle, when its structure produces irregular flow field disturbances under non-centrosymmetric conditions, the flow field downstream of it will not produce clear swirling flow, and it will not have more impact on the performance of the pump; the axial velocity distribution uniformity δ and the velocity weighted average angle θ, θ’ have obvious direct effects on efficiency, and in the δ interval of each working condition in this paper (the difference between the maximum value and the minimum value of δ is 0.093), the speed weighted average angle has a greater impact on efficiency.
Nomenclature.
Q Rate of flow
δ Axial velocity distribution uniformity
θ Weighted average angle parameter of velocity
θi Absolute axial velocity angle
θ′ Weighted average angle parameter of velocity
η Efficiency
H Head
Numerical analysis of the static characteristic of orifice-type throttled aerostatic journal bearings
Authors: Zhang X H , Ke C L , Peng N , Xiong L Y , Liu L Q 
Published: April 2021

Abstract
The static characteristic of aerostatic journal bearing was studied by numerically simulating the state non-linear Reynolds equation. The finite difference method was used to solve Reynolds equation in MATLAB programming. The relation-ship between the static characteristics and hydrodynamic effect and hydrostatic effect were analyzed. The results show that the load capacity of bearing is directly proportional to the eccentricity ratio, the rotating speed, the air supply pressure and the diameter of orifices; increasing eccentricity ratio, the rotating speed is conducive to reduce the rotor attitude angle and improve the stability of the rotor; increasing the length diameter ratio of bearing and selecting the appropriate orifice position are beneficial to reduce the air consumption of bearing.
Impact of blade leading edge film coolant on the blade tip phantom cooling
Authors: Li F , Liu Z , Feng Z P 
Published: April 2021

Abstract
Numerical simulations are carried out to predict the tip phantom cooling from blade leading edge (LE) coolant. The impact of spanwise angle of the blade LE film holes on the blade tip phantom cooling are investigated in detail under various the mass flow ratios (MFR) of coolant to mainstream from 0.3% to 1.3%. The results demonstrate that the LE film coolant could help cool the tip. These coolants mainly affect the aerothermal performance of the tip forepart and have little impact on that of the tip rear part. Increasing the coolant MFR has an obvious improvement on the tip phantom cooling level, the area-averaged cooling effectiveness could increase more than 2 times in comparing the cases with a higher MFR and a lower one. The cooling effectiveness on the LE surface first increase then decrease as a result of these coolants lift-off the LE surface with the increasing MFR. However, the LE film holes spanwise angle almost has no impact on the tip phantom cooling level at a lower MFR and even deteriorate the LE heat transfer procedure, where the cooling effectiveness decreases as the film holes spanwise angle increases.
Science and Technology Park as an Urban Element Towards Society Scientific Innovation Evolution
Authors: Almaamory Afnan Tuama , Slik Ghada Al 
Published: April 2021

Abstract
The idea of Science and Technology Parks (STP) emerged in the 1950s. The Parks have accumulated several architectural functions, including research centers, scientific exhibitions and innovator residence, etc. As these Parks gradually spread, some of them were linked to university complexes, while others had independent sites. The STP have been linked to the prosperity of society by providing an environment that fosters a culture of innovation and transforming research and ideas based on innovation into a commercially marketed product. However, the functional architectural concept of the STP remained unclear. The objective of this paper is to clarifying the stages of development of Parks architecture, investigating their activities, their linkage regarding planning and design, and the way they act as means to evolve innovation in societies.
International comparison of noise in areal surface topography measurements
Authors: Vanrusselt Maxim , Haitjema Han , Leach Richard , de Groot Peter 
Published: April 2021

Abstract
An international comparison of surface topography measurement noise was carried out. The comparison involved twelve optical surface topography instruments (focus variation instruments, confocal microscopes and coherence scanning interferometers) from six European research laboratories. The purpose of this comparison was to perform a practical test of the ISO definition and procedures for determining measurement noise on a variety of instruments, and to provide good practice guidance to the user community for quantifying, specifying and interpreting measurement noise. Despite taking steps to enable an optimal comparison by supplying a variety of specimens, where the ‘best’ could be selected and the measurement area was clearly defined, an appropriate comparison of the measurement noise beyond the actual measurement conditions was complex, as the measurement time, speed and lateral resolution were difficult to establish for most of the instruments. The results that could be obtained were: (i) the measurment noise N

M
can be reliably estimated from two measurements, (ii) noise may vary considerably between instruments, even when they have the same measurement principle, (iii) the noise in a practical measurement may be considerably higher than the noise with a levelled flat, and (iv) the ‘rms repeatability’ has little correlation to the noise determined according to the ISO specification standard, and may lead to values that are more than a hundred times smaller.
WSe2/graphene heterojunction synaptic phototransistor with both electrically and optically tunable plasticity
Authors: Sun Yilin , Lin Yuxuan , Zubair Ahmad , Xie Dan , Palacios Tomás 
Published: April 2021

Abstract
The imitation of synaptic plasticity in artificial neuromorphic devices has been widely realized based on memristors, transistors and ion devices. This development of artificial synaptic devices is expected to open up a new era for neuromorphic computing. However, the complicated functions in biological synapse are dependent on the dynamic neural activities with modulated plasticity, which is still very difficult to emulate at the device level. Here, an artificial synaptic transistor based on WSe2/graphene van der Waals heterojunction is demonstrated with both electrically and optically modulated synaptic plasticity. By changing the polarity of applied V
gs and V
ds as well as superimposed gate voltage spikes, both excitatory and inhibitory synaptic plasticity can be realized in a single device. Moreover, due to the asymmetric optical response of WSe2/graphene heterojunction, optical modulation on hysteretic behaviors is achieved and also contributes to the inversion of synaptic plasticity. Hence, this work demonstrates a coordinated regulation on synaptic plasticity under electrical and optical stimuli and provides a multi-dimensional modulation strategy to understand the underlying mechanisms of complicated neuromorphic computing and further develop multifunctional neuromorphic optoelectronics.
Significant perpendicular magnetic anisotropy in room-temperature layered ferromagnet of Cr-intercalated CrTe2
Authors: Huang Meng , Ma Zongwei , Wang Sheng , Li Si , Li Miao , Xiang Junxiang , Liu Ping , Hu Guojing , Zhang Zengming , Sun Zhe , Lu Yalin , Sheng Zhigao , Chen Gong , Chueh Yu-Lun , Yang Shengyuan A , Xiang Bin 
Published: April 2021

Abstract
Magnetic anisotropy is an important characteristic of magnetic materials. Particularly, perpendicular magnetic anisotropy (PMA) is superior for the design of spintronic devices, with the advantages of scalability, endurance, thermal stability, and low switching current density. Although a series of two-dimensional (2D) or quasi-2D layered ferromagnets have been demonstrated, the room temperature intrinsic ferromagnets with PMA is rarely found. Here, we report PMA in a room-temperature layered ferromagnet of Cr-intercalated CrTe2. By self-intercalation of the native Cr atoms, the in-plane anisotropy of CrTe2 can be switched to PMA. Meanwhile, the Cr-intercalated CrTe2 crystal can be easily exfoliated into thin flakes with thickness ∼10 nm. Besides the robust PMA at room temperature, Cr-intercalated CrTe2 also exhibits high saturation magnetization (208 emu cm−3 at 300 K), large anomalous Hall angle (2.23% at 300 K) and giant anomalous Hall factor (∼0.18 at 300 K). These excellent properties are highly desired for applications, and make Cr-intercalated CrTe2 a distinguished candidate among all existing magnetic materials. Our work reveals a promising platform for spintronic devices and offers a new route for controlling the magnetic anisotropy in layered materials.
Initial clinical experience of patient-specific QA of treatment delivery in online adaptive radiotherapy using a 1.5 T MR-Linac
Authors: Yang B , Wong Y S , Lam W W , Geng H , Huang C Y , Tang K K , Law W K , Ho C C , Nam P H , Cheung K Y , Yu S K 
Published: April 2021

Abstract

Purpose. This study aims to evaluate the performance of a commercial 1.5 T MR-Linac by analyzing its patient-specific quality assurance (QA) data collected during one full year of clinical operation. Methods and Materials. The patient-specific QA system consisted of offline delivery QA (DQA) and online calculation-based QA. Offline DQA was based on ArcCHECK-MR combined with an ionization chamber. Online QA was performed using RadCalc that calculated and compared the point dose calculation with the treatment planning system (TPS). A total of 24 patients with 189 treatment fractions were enrolled in this study. Gamma analysis was performed and the threshold that encompassed 95% of QA results (T95) was reported. The plan complexity metric was calculated for each plan and compared with the dose measurements to determine whether any correlation existed. Results. All point dose measurements were within 5% deviation. The mean gamma passing rates of the group data were found to be 96.8 ± 4.0% and 99.6 ± 0.7% with criteria of 2%/2mm and 3%/3mm, respectively. T95 of 87.4% and 98.2% was reported for the overall group with the two passing criteria, respectively. No statistically significant difference was found between adaptive treatments with adapt-to-position (ATP) and adapt-to-shape (ATS), whilst the category of pelvis data showed a better passing rate than other sites. Online QA gave a mean deviation of 0.2 ± 2.2%. The plan complexity metric was positively correlated with the mean dose difference whilst the complexity of the ATS cohort had larger variations than the ATP cohort. Conclusions. A patient-specific QA system based on ArcCHECK-MR, solid phantom and ionization chamber has been well established and implemented for validation of treatment delivery of a 1.5 T MR-Linac. Our QA data obtained over one year confirms that good agreement between TPS calculation and treatment delivery was achieved.
EMG based classification for pick and place task
Authors: Khan Salman Mohd , Khan Abid Ali , Farooq Omar 
Published: April 2021

Abstract
The hand amputee is deprived of number of activities of daily living. To help the hand amputee, it is important to learn the pattern of muscles activity. There are several elements of tasks, which involve forearm along with the wrist and hand. The one very important task is pick and place activity performed by the hand. A pick and place action is a compilation of different finger motions for the grasping of objects at different force levels. This action may be better understood by learning the electromyography signals of forearm muscles. Electromyography is the technique to acquire electrical muscle activity that is used for the pattern recognition technique of assistive devices. Regarding this, the different classification characterizations of EMG signals involved in the pick and place action, subjected to variable grip span and weights were considered in this study. A low-level force measuring gripper, capable to bear the changes in weights and object spans was designed and developed to simulate the task. The grip span varied from 6 cm to 9 cm and the maximum weight used in this study was 750 gms. The pattern recognition classification methodology was performed for the differentiation of phases of the pick and place activity, grip force, and the angular deviation of metacarpal phalangeal (MCP) joint. The classifiers used in this study were decision tree (DT), support vector machines (SVM) and k-nearest neighbor (k-NN) based on the feature sets of the EMG signals. After analyses, it was found that k-NN performed best to classify different phases of the activity and relative deviation of MCP joint with an average classification accuracy of 82% and 91% respectively. However; the SVM performed best in classification of force with a particular feature set. The findings of the study would be helpful in designing the assistive devices for hand amputee.
Relativity and its philosophy
Authors: Wallace David 
Published: April 2021

Abstract
This chapter discusses how relativity theory affects our ideas about space, time, and motion. The special theory of relativity does not introduce the idea that motion is relative: it combines that idea, already present in Newtonian physics, with the idea that the speed of light does not depend on the motion of the source. This combination has surprising consequences: that moving clocks run slow; that moving rods shrink. This is apparently in flat contradiction with the relativity principle. The resolution of this paradox looks very different depending on one’s view of what spacetime is: is it simply a codification of physics, or can it do explanatory work in its own right. Thus the paradox lets us get clearer on what is at stake in these questions about the nature of spacetime. Relativity also imperils the idea that simultaneity—the relationship between two events when they occur at the same time—is relative and/or conventional. The epilogue of the chapter briefly discusses the general theory of relativity.
Mysteries of the quantum
Authors: Wallace David 
Published: April 2021

Abstract
This chapter introduces the central mysteries of quantum mechanics. Quantum mechanics is an enormously successful theory that lies at the heart of modern physics, but there is no agreement on how to understand it. Simple experiments with light demonstrate why: in understanding those experiments, we have to shift inconsistently back and forth between thinking of the theory as assigning indefinite, delocalized, but known properties to a system, and assigning definite, localized, but unknown properties (this is called the ‘problem of measurement’). Furthermore, when we break a system into subsystems, the state of the system is not determined by the states of the subsystem (this is called ‘entanglement’), and simple arguments seem to tell us that the physical properties of entangled subsystems can influence one another non-locally—faster than light. These three mysteries—measurement, entanglement, non-locality—need to be addressed by any attempt to make sense of quantum theory.
Ancient reefs and islands
Authors: Sheppard Charles 
Published: April 2021

Abstract
Reefs in deep geological time have been built by a succession of different kinds of life: plant, bacterial, and animal. Stromatolites and bryozoans were major reef-builders that persist today in minor or non-reef-building forms, sponges built entire reefs and are still important reef components, while several groups of major reef-builders flourished for a while and then became extinct: archaeocyathids which were similar to sponges, and coral-like forms including rugose and tabulate corals. Today’s reef-builders, cnidarian corals, appeared well after the great Permian-Triassic extinction event. All of these groups deposited vast quantities of limestone rock on which they live, often visible today as low mountain ranges. Reefs grow to the surface but not beyond, but upon them sand and sediments may build up, forming an island that attracts plants, then birds and other terrestrial forms of life. The sediments become cemented with the aid of rainwater too, and ‘low islands’ develop. Many islands also show their old, central volcanoes, resulting in the vast array of different combinations of coral island type. Today, however, there is a coral reef crisis due to overexploitation of a reef’s rich resources, from pollution of several kinds, and climate change.
Reef fish and other major predators
Authors: Sheppard Charles 
Published: April 2021

Abstract
Fish, like corals, have geographical patterns across regions and across individual reefs, being structured in the latter case by wave energy and depth. The thousands of species show a variety of feeding patterns. Detritus feeders are very abundant, feeding on the detritus on the seabed, especially in the fine, filamentous algal turf on apparently bare rock. Plankton feeders are common also, and herbivorous fishes show a large abundance, perhaps a quarter of the total species present, cropping algae that otherwise would grow unchecked and smother coral. Since turf algae also contain many micro-species and detritus, most herbivores also ingest much food other than simple plant material. Carnivores range from extreme specialists, such as polyp-picking butterflyfish, to generalists. Sharks and barracuda only consume other fish and generally are at the top of their food chains. The complicated ecological structure of the food webs can be clarified by analysing nitrogen isotope ratios in their tissues. Other important coral carnivores include the crown of thorns starfish, which can remove almost all living coral on a reef when it develops into plagues. Overfishing by humans greatly disturbs the equilibrium of a reef, and this is increasingly causing reef degradation.
Doing something about it
Authors: Sheppard Charles 
Published: April 2021

Abstract
Several political instruments are in place to tackle effects of climate change and help arrest the global decline of coral reefs. Unfortunately, most are inadequate and anyway are being ignored by many important nations. Rising ocean temperatures are not linear, but act in pulses, so that reefs degrade in steps rather than smoothly. Terminally degraded reefs are now common, and those in very good condition are rare. Several potential solutions have been proposed, none being adequate alone but all being needed to arrest the decline. Arresting the rise in CO2 is a key, long-term requirement, yet levels of this gas are still increasing, as are local requirements such as effective pollution and overfishing controls. Also important is limiting resource extraction, which essentially means limiting human populations. Most scientists consider saving coral reefs now to be a political and sociological problem, not a scientific one. We have lost nearly half the world’s coral reefs and if societies cannot act in what is becoming a diminishing window of opportunity, we will lose most of the rest within another human lifetime.