scholarly journals Concentric Metawaveguide Cloaking

2021 ◽  
Author(s):  
Mojtaba Dehmollaian ◽  
Christophe Caloz
Keyword(s):  
Ab Initio ◽  
Transformation Optics ◽  
Superior Performance ◽  
And Performance ◽  
Bent Waveguides

We introduce here a novel type of cloaking, based on a circular concentric meta-waguide structure, where the metawaveguides are bent waveguides with porous metasurface walls. In contrast to the cloak implementation reported in~\cite{schurig2006metamaterial}, which only \emph{approximates} the ideally perfect transformation-optics cloak because of prohibitive fabrication complexity, this cloak is designed ab initio for optimal cloaking, and offers therefore largely superior performance. Its combined simplicity and performance arguably makes it the most practical existing cloak reported so far.

scholarly journals ECLB: Edge-Computing-Based Lightweight Blockchain Framework for Mobile Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Qingqing Xie ◽  
Fan Dong ◽  
Xia Feng
Keyword(s):  
Mobile Devices ◽  
Security Analysis ◽  
Edge Computing ◽  
Mobile Systems ◽  
Superior Performance ◽  
Consensus Protocol ◽  
Open Problems ◽  
Blockchain Technology ◽  
Natural Solution ◽  
And Performance

The blockchain technology achieves security by sacrificing prohibitive storage and computation resources. However, in mobile systems, the mobile devices usually offer weak computation and storage resources. It prohibits the wide application of the blockchain technology. Edge computing appears with strong resources and inherent decentralization, which can provide a natural solution to overcoming the resource-insufficiency problem. However, applying edge computing directly can only relieve some storage and computation pressure. There are some other open problems, such as improving confirmation latency, throughput, and regulation. To this end, we propose an edge-computing-based lightweight blockchain framework (ECLB) for mobile systems. This paper introduces a novel set of ledger structures and designs a transaction consensus protocol to achieve superior performance. Moreover, considering the permissioned blockchain setting, we specifically utilize some cryptographic methods to design a pluggable transaction regulation module. Finally, our security analysis and performance evaluation show that ECLB can retain the security of Bitcoin-like blockchain and better performance of ledger storage cost in mobile devices, block mining computation cost, throughput, transaction confirmation latency, and transaction regulation cost.

scholarly journals Response To Light Intensity of Sun And Shade On Two Cool Season Turfgrass

2021 ◽  
Author(s):  
Lili Dong ◽  
Liangbing Xiong ◽  
Qianjiao Zheng ◽  
Xiaoyang Sun ◽  
Zhixin Guo ◽  
...  
Keyword(s):  
Light Intensity ◽  
Anatomical Structure ◽  
Superior Performance ◽  
Physiological Adaptation ◽  
Cool Season ◽  
Daily Growth ◽  
Chl A ◽  
Sun And Shade ◽  
Normal Light ◽  
And Performance

Abstract Background: Obtaining superior performance of SupraNova and Lark C3 turfgrasses under shade conditions is a challenging task. Both durability and performance of turfgrass are significantly affected by shade. In particular, morphological and physiological adaptation to low light is critical for maintaining quality and overall performance in turfgrass plants. Results: The purpose of this study was to study the response of SupraNova and Lark turfgrass morphology and photo-physiological potential to shading. The plants of 'SupraNova' and 'Lark' were collected from the lawn plots of the Horticulture Research Center of Northeast Agricultural University of China for 2 years and treated with gradient shading 35.62% after 2 months of culture, normal light intensity 70.79 % and 93.45% with full sun as the contrast represented by CK for comparison. Lark showed TQ and TCI in shady stage compared with SupraNova. Lark showed strong resistance to MDA, H2O2, O2-, SOD, POD, CAT and AsA, indicating that the antioxidant system of C3 turfgrass at 35.6% shade level. Under 70.79% shade treatment, MDA, H2O2, O2-, SOD, POD, CAT and AsA of the two cultivars decreased the most, and the longer the shading time, the average daily growth of the two turfgrasses increased first and then decreased. Lark outperformed SupraNova throughout the shading treatment, with 70.79% and 93.45%, respectively. Lark showed increased Chl A and Chl (A/B) in response to different shading levels, while SupraNova had the highest concentrations of Chl B and total Chl. Chlorophyll fluorescence qP, ETR, and Fv/Fm decreased significantly when shaded at 93.45%;Conclusion: The results of this study proved that decrease was more significant in SupraNova than Lark, and shading caused more severe changes in leaf morphology and anatomical structure than Lark turfgrass has the highest negative tolerance than SupraNova turfgrass, which is due to the better photosynthetic product transport capacity of Lark plants. In its anatomical structure, and" vascular bundle sheath structure, which enables it to have higher photosynthetic efficiency to adapt to negative stress. SupraNova and Lark first increased and then decreased with the increase of shade degree

Design and Performance Analysis of a Supercritical CO2 Centrifugal Compressor With Variable Geometry

2021 ◽  
Author(s):  
Gang Fan ◽  
Kang Chen ◽  
Shaoxiong Zheng ◽  
Yang Du ◽  
Yiping Dai ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Optimization Design ◽  
High Efficiency ◽  
Superior Performance ◽  
Variable Geometry ◽  
Power Cycles ◽  
Operating Range ◽  
Stable Operating ◽  
And Performance ◽  
Geometry Method

Abstract The supercritical carbon dioxide (SCO2) Brayton cycle is one of the most promising power cycles due to its high efficiency, compactness and environmentally friendliness. The centrifugal compressor is a key component of small and medium SCO2 Brayton cycles, and its efficiency has a significant impact on the cycle efficiency. Since the required electric load of power cycles always fluctuates over the year, the SCO2 compressor will operate away from its design point and the narrow stable operating range of a compressor is always a restriction. In this paper, the variable-geometry method, which refers to the combination of a variable inlet-guide-vanes and variable diffuser vanes is proposed for the operating range extension of SCO2 compressors. A set of one-dimensional (1D) loss correlations has been found to accurately predict various losses of the SCO2 compressor components. Based on the 1D thermodynamic model, two programs with internal MATLAB codes coupled with the NIST REFPROP database have been developed for preliminary optimization design and off-design performance predictions of the variable geometry SCO2 compressor. The contributions from the variable-inlet prewhirl and variable diffuser vanes to the shifts of the surge line and choke line are discussed in this paper. The results show the variable-geometry SCO2 compressor has a superior performance at off-design conditions and a wider operating range.

An empirical investigation of buyer–supplier relationship typologies and their behavioral and performance outcomes

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jin Li ◽  
Linlin Chai ◽  
Chanchai Tangpong ◽  
Michelle Hong ◽  
Rodney D. Traub
Keyword(s):  
Performance Measures ◽  
Online Survey ◽  
Performance Outcomes ◽  
Superior Performance ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Content Type ◽  
Behavioral Dynamics ◽  
And Performance ◽  
Supplier Relationship

Purpose This study aims to examine empirically the existence of four classical and four emerging buyer–supplier relationship (BSR) types and how they differ in terms of behavioral dynamics and performance measures. Design/methodology/approach This study uses an online survey to collect data from 371 purchasing managers in the USA. Findings A cluster analysis statistically supports the existence of five of these eight BSR types, including strategic/bilateral partnership, market/discrete, supplier-led collaboration, captive supplier/buyer dominant and captive buyer/supplier dominant BSRs. Further, ANOVA tests show that these five BSRs differ in terms of behavioral outcomes and performance measures. Research limitations/implications This study is based on a cross-sectional survey so it cannot examine how these BSR types may evolve over time, and it is not suitable to examine some rare types of BSRs. In addition, this study does not consider contextual factors that may moderate the influence of BSR types on the behavioral dynamics and performance measures. Practical implications Managers should consider the potential to be able to develop and enhance a strategic/bilateral relationship with their supply chain partners, which in at least some circumstances can lead to superior performance results. Similar observations can be made with respect to supplier-led and, to a lesser degree, buyer-led collaboration. Originality/value Most existing research of the BSR types is largely a product of theoretical classifications, and there is also a lack of research of their performance implications. This study fills these gaps in the literature.

The Causal Effects of Proximity on Investment: Evidence from Flight Introductions

2019 ◽  
Vol 55 (6) ◽  
pp. 1978-2004 ◽  
Author(s):  
Jesse Ellis ◽  
Leonardo Madureira ◽  
Shane Underwood
Keyword(s):  
Mutual Funds ◽  
Fixed Effects ◽  
Investment Decisions ◽  
Relevant Information ◽  
Causal Effects ◽  
Superior Performance ◽  
Firm Level ◽  
Exogenous Shock ◽  
And Performance ◽  
Fund Investment

We use the introduction of direct flights as an exogenous shock to the travel time between mutual funds and firms to estimate the causal effects of proximity on fund investment decisions and performance. We find that a fund invests significantly more in firms that become more proximate following the introduction of direct flights and that these more proximate investments exhibit superior performance. Our findings are robust to including a variety of fixed effects and potential confounders such as firm-level shocks, fund-level shocks, and time trends. Collectively, our results indicate that proximity enhances investors’ ability to acquire value-relevant information about firms.

scholarly journals Leveraging Logistics Competence in New Product Sourcing: The Role of Strategic Intent and Impact on Performance

Logistics ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 24
Author(s):  
Myung Kyo Kim ◽  
Ram Narasimhan ◽  
Tobias Schoenherr
Keyword(s):  
Superior Performance ◽  
Strategic Intent ◽  
South Korean ◽  
Selection Decisions ◽  
Path Modelling ◽  
Construct Measurement ◽  
And Performance ◽  
The Impact ◽  
Moderating Role

The purpose of the present research is to examine and compare product and logistics competencies in supplier selection decisions, which can serve as a crucial building block for competitive differentiation, in the context of the unique private label (PL) supply chain. This study also hypothesizes about the impact of product and logistics competence on the retailer’s financial performance. Lastly, the moderating role of the product type in the proposed research model is explored. Partial least squares path modelling is used to analyze the dataset drawn from major South Korean retailers, due to the exploratory nature of the research and the use of both reflective and formative construct measurement items. Overall, the results of this study demonstrate that relationships between the desire for a particular strategic intent and performance are more complex than previous studies have implied. The findings of this research offer possible explanations on an important but understudied aspect of PL success: why not all PLs (even of the same retailer) are thriving even in a rapidly growing PL industry. We further elicit strategic recommendations for retailers in selecting PL suppliers and for PL manufacturers to differentiate themselves and achieve a superior performance.

Ab initio study of a 2D h-BAs monolayer: a promising anode material for alkali-metal ion batteries

2019 ◽  
Vol 21 (33) ◽  
pp. 18328-18337 ◽  
Author(s):  
Nabil Khossossi ◽  
Amitava Banerjee ◽  
Younes Benhouria ◽  
Ismail Essaoudi ◽  
Abdelmajid Ainane ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Ab Initio ◽  
Anode Material ◽  
Metal Ion ◽  
Superior Performance ◽  
Two Dimensional ◽  
Ab Initio Study ◽  
Alkali Metal Ion ◽  
Key Steps ◽  
Selection Of

The selection of a suitable two dimensional anode material is one of the key steps in the development of alkali metal ion batteries to achieve superior performance with an ultrahigh rate of charging/discharging capability.

scholarly journals The effect of low- vs high-cadence interval training on the freely chosen cadence and performance in endurance-trained cyclists

2016 ◽  
Vol 41 (6) ◽  
pp. 666-673 ◽  
Author(s):  
Anthony G. Whitty ◽  
Aron J. Murphy ◽  
Aaron J. Coutts ◽  
Mark L. Watsford
Keyword(s):  
Perceived Exertion ◽  
Average Power ◽  
Time Trial ◽  
Interval Training ◽  
Performance Measure ◽  
Rating Of Perceived Exertion ◽  
Superior Performance ◽  
Strength Development ◽  
And Performance ◽  
High Cadence

The aim of this study was to determine the effects of high- and low-cadence interval training on the freely chosen cadence (FCC) and performance in endurance-trained cyclists. Sixteen male endurance-trained cyclists completed a series of submaximal rides at 60% maximal power (Wmax) at cadences of 50, 70, 90, and 110 r·min−1, and their FCC to determine their preferred cadence, gross efficiency (GE), rating of perceived exertion, and crank torque profile. Performance was measured via a 15-min time trial, which was preloaded with a cycle at 60% Wmax. Following the testing, the participants were randomly assigned to a high-cadence (HC) (20% above FCC) or a low-cadence (LC) (20% below FCC) group for 18 interval-based training sessions over 6 weeks. The HC group increased their FCC from 92 to 101 r·min−1 after the intervention (p = 0.01), whereas the LC group remained unchanged (93 r·min−1). GE increased from 22.7% to 23.6% in the HC group at 90 r·min−1 (p = 0.05), from 20.0% to 20.9% at 110 r·min−1 (p = 0.05), and from 22.8% to 23.2% at their FCC. Both groups significantly increased their total distance and average power output following training, with the LC group recording a superior performance measure. There were minimal changes to the crank torque profile in both groups following training. This study demonstrated that the FCC can be altered with HC interval training and that the determinants of the optimal cycling cadence are multifactorial and not completely understood. Furthermore, LC interval training may significantly improve time-trial results of short duration as a result of an increase in strength development or possible neuromuscular adaptations.

scholarly journals Optimization of Friction Welding Process Parameters for 42Cr9Si2 Hollow Head and Sodium Filled Engine Valve and Valve Performance Evaluation

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1123
Author(s):  
Fuqiang Lai ◽  
Shengguan Qu ◽  
Roger Lewis ◽  
Tom Slatter ◽  
Ge Sun ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Friction Welding ◽  
Elevated Temperatures ◽  
Welding Process ◽  
Process Parameter ◽  
Superior Performance ◽  
Welding Parameters ◽  
Manufacturing Method ◽  
Rotating Bending Fatigue ◽  
And Performance

Due to their design, hollow cavity and filled sodium, hollow head and sodium filled engine valves (HHSVs) have superior performance to traditional solid valves in terms of mass and temperature reduction. This paper presents a new manufacturing method for 42Cr9Si2 steel hollow head and sodium filled valves. An inertia friction welding process parameter optimization was conducted to obtain a suitable process parameter range. The fatigue strength of 42Cr9Si2 steel at elevated temperatures was evaluated by rotating bending fatigue test with material specimens. Performance evaluation tests for real valve components were then carried out using a bespoke bench-top apparatus, as well as a stress evaluation utilizing a finite element method. It was proved that the optimized friction welding parameters of HHSV can achieve good welding quality and performance, and the HHSV specimen successfully survived defined durability tests proving the viability of this new method. The wear resistance of the HHSV specimens was evaluated and the corresponding wear mechanisms were found to be those classically defined in automotive valve wear.

scholarly journals Intake and performance of confined bovine fed fresh or ensilaged sugar cane based diets and corn silage

2011 ◽  
Vol 40 (5) ◽  
pp. 1095-1103 ◽  
Author(s):  
Gustavo Chamon de Castro Menezes ◽  
Sebastião de Campos Valadares Filho ◽  
Felipe Antunes Magalhães ◽  
Rilene Ferreira Diniz Valadares ◽  
Laura Franco Prados ◽  
...  
Keyword(s):  
Organic Matter ◽  
Calcium Oxide ◽  
Sugar Cane ◽  
Dry Matter ◽  
Subcutaneous Fat ◽  
The Body ◽  
Corn Silage ◽  
Neutral Detergent Fiber ◽  
Superior Performance ◽  
And Performance

It was evaluated intake, total apparent digestibility, performance and feeding behavior of bovine fed diets constituted of corn silage, crushed sugar cane given fresh or crushed and given 72 hours after storage, ensilaged sugar cane with or without 1% of calcium oxide and concentrate at the proportion of 1% of the body weight. It was used 35 bovines, distributed in a random block design, with 5 treatments and 6 repetitions. The animals were housed in collective stalls with troughs individualized by electronic gates. The animals fed diet with corn silage presented greater intake of all nutrients and greater total digestibility of dry matter, organic matter, neutral detergent fiber and total digestible nutrients, as well as greater weight gain and subcutaneous fat thickness. Animals fed diet with fresh sugar cane presented greater nutrient intake as well as better dry matter digestibility, ether extract and TDN content and a superior performance in relation to animals fed ensilaged sugar cane diets. Animals fed silage of sugar cane with calcium oxide presented greater digestibility of organic matter, NFC and content of TDN but they did not differ on performance in relation to the use of silage of sugar cane without calcium oxide. Intake and performance of animals did not change with or without storage of sugar cane. It was concluded that animals fed diets with corn silage present performances superior to the ones which are fed sugar cane based diets, and animals fed fresh sugar diet are superior to the animals fed diets with sugar cane silage.

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