scholarly journals Fabrication and Characterisation of Aligned Discontinuous Carbon Fibre Reinforced Thermoplastics as Feedstock Material for Fused Filament Fabrication

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4671
Author(s):  
Lourens Blok ◽  
Marco Longana ◽  
Benjamin Woods
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Selection Process ◽  
Fibre Composite ◽  
Fibre Length ◽  
Fused Filament Fabrication ◽  
Continuous Fibre ◽  
And Performance ◽  
Reinforced Thermoplastics ◽  
High Level

In this work, aligned discontinuous fibre composite (ADFRC) tapes were developed and investigated as precursors for a novel 3D printing filament. ADFRCs have the potential to achieve mechanical performance comparable to continuous fibre reinforced composites, given sufficient fibre length and high level of alignment, and avoid many of the manufacturing difficulties associated with continuous fibres, e.g., wrinkling, bridging and corner radii constraints. Their potential use for fused filament fabrication (FFF) techniques was investigated here. An extensive down-selection process of thermoplastic matrices was performed, as matrix properties significantly impact both the processing and performance of the filament. This resulted in four candidate polymers (ABS, PLA, Nylon, PETG) which were used to manufacture ADFRC tapes with a Vf of 12.5% using the high performance discontinuous fibre (HiPerDiF) technology and an in-house developed continuous consolidation module. Tensile stiffness and strength up to 30 GPa and 400 MPa respectively were recorded, showing that a discontinuous fibre filament has the potential to compete with continuous fibre filaments.

A review on fibre reinforced composite printing via FFF

2019 ◽  
Vol 25 (6) ◽  
pp. 972-988 ◽  
Author(s):  
Isaac Ferreira ◽  
Margarida Machado ◽  
Fernando Alves ◽  
António Torres Marques
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Performance Improvements ◽  
Different Types ◽  
Significant Research ◽  
Comprehensive Survey ◽  
3D Printed ◽  
Reinforced Thermoplastics

Purpose In industry, fused filament fabrication (FFF) offers flexibility and agility by promoting a reduction in costs and in the lead-time (i.e. time-to-market). Nevertheless, FFF parts exhibit some limitations such as lack of accuracy and/or lower mechanical performance. As a result, some alternatives have been developed to overcome some of these restrictions, namely, the formulation of high performance polymers, the creation of fibre-reinforced materials by FFF process and/or the design of new FFF-based technologies for printing composite materials. This work aims to analyze these technologies. Design/methodology/approach This work aims to study and understand the advances in the behaviour of 3D printed parts with enhanced performance by its reinforcement with several shapes and types of fibres from nanoparticles to continuous fibre roving. Thus, a comprehensive survey of significant research studies carried out regarding FFF of fibre-reinforced thermoplastics is provided, giving emphasis to the most relevant and innovative developments or adaptations undergone at hardware level and/or on the production process of the feedstock. Findings It is shown that the different types of reinforcement present different challenges for the printing process with different outcomes in the part performance. Originality/value This review is focused on joining the most important researches dedicated to the process of FFF-printed parts with different types reinforcing materials. By dividing the reinforcements in categories by shape/geometry and method of processing, it is possible to better quantify performance improvements.

https://imsciences.edu.pk/files/journals/vol12_2/New%201%20MA.864.pdf

2020 ◽  
Vol 12 (2) ◽  
pp. 19-50 ◽  
Author(s):  
Muhammad Siddique ◽  
Shandana Shoaib ◽  
Zahoor Jan
Keyword(s):  
Organizational Performance ◽  
Structural Equation ◽  
High Performance ◽  
Service Sector ◽  
Performance Outcomes ◽  
Theory And Practice ◽  
Relational Coordination ◽  
Multiple Sources ◽  
And Performance ◽  
High Level

A key aspect of work processes in service sector firms is the interconnection between tasks and performance. Relational coordination can play an important role in addressing the issues of coordinating organizational activities due to high level of interdependence complexity in service sector firms. Research has primarily supported the aspect that well devised high performance work systems (HPWS) can intensify organizational performance. There is a growing debate, however, with regard to understanding the “mechanism” linking HPWS and performance outcomes. Using relational coordination theory, this study examines a model that examine the effects of subsets of HPWS, such as motivation, skills and opportunity enhancing HR practices on relational coordination among employees working in reciprocal interdependent job settings. Data were gathered from multiple sources including managers and employees at individual, functional and unit levels to know their understanding in relation to HPWS and relational coordination (RC) in 218 bank branches in Pakistan. Data analysis via structural equation modelling, results suggest that HPWS predicted RC among officers at the unit level. The findings of the study have contributions to both, theory and practice.

Additively Manufactured Continuous Fibre-Reinforced Thermoplastics for Mechanisms Subjected to Predominant Inertial Load: A Case Study

2020 ◽  
Author(s):  
Luca Luzi ◽  
Giacomo Quercioli ◽  
Riccardo Pucci ◽  
Guido Bocchieri ◽  
Rocco Vertechy ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Topology Optimization ◽  
High Performance ◽  
Permanent Magnet Synchronous Motor ◽  
Three Dimensional ◽  
Direct Drive ◽  
Continuous Fibre ◽  
Mechanical Components ◽  
Reinforced Thermoplastics

Abstract In the last decade, the adoption of additive manufacturing technologies (AMT) (3D printing) has increased significantly in many fields of engineering, initially only for rapid prototyping and more recently also for the production of finished parts. With respect to the long-established material subtractive technologies (MST), AMT is capable to overcome several limitations related to the shape realization of high-performance mechanical components such as those conceived via topology optimization and generative design approaches. In the field of structures and mechanisms, a major advantage of AMT over MST is that, for the same loading and constraining conditions (including kinematic and overall encumbrance), it enables the realization of mechanical components with similar stiffness but smaller volume (thus smaller weight, density being equal). Recently, the potentialities of AMT have also been increased by the introduction of the fuse filament deposition modeling (FDM) of continuous fibre-reinforced thermoplastics (CFRT), which combines the ease of processing of plastic AMT with the strength and specific modulus of the printed components that are comparable to those attainable via metallic AMT. In this context, the present paper investigates the potentialities of FDM-CFRT for the realization of mechanisms subjected to predominant inertial loads such as those found in automated packaging machinery. As a case study a Stephenson six-bar linkage powered in direct drive by a permanent magnet synchronous motor is considered. Starting from an existing mechanism realized in aluminum alloy with traditional MST, a newer version to be realized with FDM-CFRT has been conceived by keeping the kinematics fixed and by redesigning the links via three-dimensional topology optimization. To provide a fair comparison with the more traditional design/manufacturing approach, size optimization of the original mechanism made in aluminum alloy has also been performed. Comparison of the two versions of the mechanism highlights the superior performances of the one manufactured via FDM-CFRT in terms of weight, motor torque requirements and motion precision.

scholarly journals The life of high-level athletes: The challenge of high performance against the time constraint

2016 ◽  
Vol 53 (2) ◽  
pp. 234-249 ◽  
Author(s):  
Fabrice Burlot ◽  
Rémi Richard ◽  
Helene Joncheray
Keyword(s):  
High Performance ◽  
Elite Athletes ◽  
Time Constraint ◽  
Sport Expertise ◽  
Pace Of Life ◽  
And Performance ◽  
High Level ◽  
State Of Tension ◽  
Sporting Performance

The conditions for high performance have changed considerably over the last few years. Athletes must spend more time training and competing, devote a lot of time to mental, physical and nutritional professionals and continue to respond to some constraints such as studying, spending time with their families, friends and quality of life. In this context and based on the work of Rosa, we wonder about the capacity of elite athletes to combine all these constraints, namely to manage the acceleration in their pace of life, in order to be able to achieve always more and better in the same time unit. To address this issue, we interviewed 42 French high-level athletes who train at the National Institute of Sport, Expertise and Performance (INSEP). Results show that to suit their goals, athletes implement arrangement and adjustment strategies aimed at making the time they have wholly useful and efficient. This time constraint puts athletes in a perpetual state of tension, on the verge of a good or poor life. The paper shows how the question of time, and particularly the acceleration of pace of life, is vital for modern sporting performance.

scholarly journals What Makes Employees Productive and Have High Performance? Human Capital Investment in Universities

2020 ◽  
pp. 21-36
Author(s):  
Fitri Nurmahmudah ◽  
Eka Cahya Sari Putra
Keyword(s):  
Human Capital ◽  
Capital Investment ◽  
High Performance ◽  
Evaluation Method ◽  
Net Present Value ◽  
Pearson Correlation ◽  
Human Capital Investment ◽  
Correlation Technique ◽  
And Performance ◽  
High Level

The study describes the evaluation results concerning the improvement of the education levels among the employees of a university in Indonesia by making an investment in education. The study is aimed at investigating the employees’ productivity and performance after making an investment in education. This study with evaluation method using discrepancy model. The sample of the study consisted of 255  non-academic university employees. Data were collected by way of a questionnaire on Guttmann scale. The questionnaire was validated by using logical and empirical validation by a Pearson correlation technique and reliability by KR-20 technique. The data analysis with descriptive. To calculate the capital human investment, the human capital investment formula was used for finding payback period, benefit/cost ration, return-on-investment, net-present-value, and internal-rate-of-return. The results of the study showed that the employees who made human capital investment in education were able to increase their productivity and performance as their insights, knowledge, and skills improved. The research findings were able to give insights to leaders in high-level institutions or government institutions that investing in education is truly essential, needs more attention, and needs to be done by employees.

High-End Storage

2012 ◽  
pp. 132-152
Author(s):  
Isabel Schwerdtfeger
Keyword(s):  
Real Time ◽  
Data Storage ◽  
High Performance ◽  
Storage System ◽  
Real Time Processing ◽  
Storage Solutions ◽  
Future Demands ◽  
And Performance ◽  
Extreme Scale ◽  
High Level

This chapter discusses the challenges high-end storage solutions will have with future demands. Due to heavy end-user demands for real-time processing of data access, this need must be addressed by high-end storage solutions. But what type of high-end storage solutions address this need and are suitable to ensure high performance write and retrieval of data in real-time from high- end storage infrastructures, including read and write access from digital archives? For this reason, this chapter reviews a few disk and tape solutions as well as combined disk- and tape storage solutions. The review on the different storage solutions does not focus on compliance of data storage management, but on available commercial high-end systems, addressing scalability and performance requirements both for online storage and archives. High level requirements aid in identifying high-end storage system features and support Extreme Scale infrastructures for the amount of data that high-end storage systems will need to manage in future.

Special Issue High Performance Parallel Functional Programming

2005 ◽  
Vol 15 (3) ◽  
pp. 351-352
Author(s):  
P. W. TRINDER
Keyword(s):  
Performance Analysis ◽  
Functional Programming ◽  
High Performance ◽  
Parallel Programs ◽  
Special Issue ◽  
Parallel And Distributed Computing ◽  
Multiple Processors ◽  
Programming Effort ◽  
And Performance ◽  
High Level

Engineering high-performance parallel programs is hard: not only must a correct, efficient and inherently-parallel algorithm be developed, but the computations must be effectively and efficiently coordinated across multiple processors. It has long been recognised that ideas and approaches drawn from functional programming may be particularly applicable to parallel and distributed computing (e.g. Wegner 1971). There are several reasons for this suitability. Concurrent stateless computations are much easier to coordinate, high-level coordination abstractions reduce programming effort, and declarative notations are amenable to reasoning, i.e. to optimising transformations, derivation and performance analysis.

scholarly journals Development of Carbon Fiber-Reinforced Thermoplastics for Mass-Produced Automotive Applications in Japan

2021 ◽  
Vol 5 (3) ◽  
pp. 86
Author(s):  
Yi Wan ◽  
Jun Takahashi
Keyword(s):  
Carbon Fiber ◽  
Mass Production ◽  
High Performance ◽  
Mechanical Performance ◽  
Fiber Reinforced ◽  
Recent Developments ◽  
Carbon Fiber Reinforced ◽  
Material Solution ◽  
Reinforced Thermoplastics ◽  
Fiber Reinforced Thermoplastics

The application of carbon fiber-reinforced thermoplastics (CFRTPs) for automotive mass production is attracting increasing attention from researchers and engineers in related fields. This article presents recent developments in CFRTPs focusing on the systematic development of lightweight CFRTP applications for automotive mass production. Additionally, a related national project of Japan conducted at the University of Tokyo is also introduced. The basic development demands, the specific requirements of CFRTPs for lightweight applications in automotive mass production, and the current development status and basic scientific outputs are discussed. The development of high-performance CFRTPs (chopped carbon fiber tape-reinforced thermoplastics (CTTs)) and functional CFRTPs (carbon fiber mat-reinforced thermoplastics (CMTs)) is also introduced. The fabrication process control of CTTs is evaluated, which demonstrates the extreme importance of the mechanical performance. The ultralight lattice, toughened structures, and orientation designable components of CMTs provide a flexible multi-material solution for the proposed applications. Moreover, highly efficient carbon fiber recycling technology is discussed, with recycled carbon fibers exhibiting outstanding compatibility with CFRTPs. A cost sensitivity analysis of carbon fiber and CFRTPs is conducted to guarantee the feasibility and affordability of their application. This article also discusses the trends and sustainability of carbon fiber and CFRTPs usage. The importance of the object-oriented optimal development of CFRTPs is emphasized to efficiently exploit their advantages.

scholarly journals Authenticated encryption mode with blocks skipping

2021 ◽  
pp. 59-65
Author(s):  
A. V. Sokolov ◽  
D. A. Isakov
Keyword(s):  
Error Detection ◽  
High Performance ◽  
Detection Accuracy ◽  
Authenticated Encryption ◽  
Mobile Platforms ◽  
Security Systems ◽  
Power Resources ◽  
And Performance ◽  
High Level ◽  
Sequence Generator

Block symmetric ciphers are one of the most important components of modern information security systems. At the same time, in addition to the structure of the applied block symmetric cipher, the cryptographic strength and performance of the information protection system is largely determined by the applied encryption mode. In addition to high performance and high-quality destruction of block statistics, modern encryption modes should also protect encrypted information from occurred or intentionally introduced errors. In this paper, we have developed an encryption mode with blocks skipping and using a pseudo-random key sequence generator, which allows checking the integrity of encrypted information with accurate detection of the place where an error was introduced. In this case, the error detection accuracy is determined by the adjustable parameter of the macroblock size and can be set depending on the level of importance of the protected information. The developed encryption mode is characterized by the following key advantages: reducing the number of required encryption operations by half, while providing a high level of cryptographic quality; more effective destruction of macroblock statistics due to the use of an additional generator of pseudo-random key sequences, the impossibility of propagation of the occurred (intentionally introduced) error outside the macroblock, as well as higher values of the number of protection levels due to the possibility of classifying the initial states of the applied generators of pseudo-random key sequences. As proposed in this paper, the mode of authenticated encryption with blocks skipping can be recommended for use on mobile platforms that are demanding both in terms of the quality and reliability of the protected information and are limited in terms of computing and power resources.

scholarly journals Improving on Half-Lightweight Male Judokas' High Performance by the Application of the Analytic Network Process

2021 ◽  
Vol 12 ◽  
Author(s):  
Sugoi Uriarte Marcos ◽  
Raúl Rodríguez-Rodríguez ◽  
Juan-José Alfaro-Saiz ◽  
Eduardo Carballeira ◽  
Maier Uriarte Marcos
Keyword(s):  
High Performance ◽  
Analytic Network Process ◽  
Added Value ◽  
Strategic Objectives ◽  
Strategic Performance ◽  
Crucial Difference ◽  
Network Process ◽  
Daily Training ◽  
And Performance ◽  
High Level

Judo is a multifactorial sport where many variables or key performance indicators (KPIs) such as force-velocity profile, bioenergetic capacity, technical and tactical skills, and cognitive and emotional competence play a role and influence the final result. While there have been many academic studies of these variables, usually in isolation, none have examined KPIs holistically or analyzed their impact on strategic performance. The main objective of the present study, therefore, is to apply a novel and easily replicable methodology to identify and prioritize the main KPIs affecting performance in professional judo. Such a methodology was applied to the High-Performance Judo Centre of Valencia, using a multi-criteria decision aid technique: the analytic network process (ANP). The ANP is used to identify and quantify cause and effect relationships not only between KPIs but also between KPIs and performance objectives. Further, the ANP offers effective results when there is a lack of historical KPI data, because it is based on experts' opinions and judgments. A judo expert group (JEG) comprising elite judo coaches and half-lightweight (under 66 kg) male judokas applied the methodology to discriminate between the characteristics required when aiming to reach high-level strategic objectives (such as participating in the Olympic Games or winning a medal in a Grand Slam/Gran Prix). The JEG, which consisted of five elite judokas, national and international champions, and three Olympic coaches—including a former European champion and silver medalist in a world championship—provided high added value to the study. The main findings were that the KPIs that made the most difference were mostly psychological, specifically motivation, stress, and team cohesion. Of these, motivation was by far the most important KPI for success in our case study, so judokas should make sure that they analyze it properly. Motivation is usually intrinsic to the competitor and should be maintained at a high level, not only during tournaments but also during daily training and lifestyle activities. Physical and other specific forms of training, as well as lifestyle KPIs, are very important for the elite competitor but are not sufficient to reach high-level objectives. The most important of these KPIs were Kumi-Kata (grip work), dual career, focus and concentration level, scouting, nutrition, and basic technique. Power and strength were the most important physical KPIs. In general, these are essential for meeting strategic objectives, but they do not make the crucial difference. This suggests that professional psychological support should be provided in daily training and that international team composition and internships should be fostered.

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