Aerodynamic Bicycle Helmet Design Using a Truncated Airfoil With Trailing Edge Modifications

2011 ◽  
Author(s):  
Bradford W. Sims ◽  
Peter E. Jenkins
Keyword(s):  
High Performance ◽  
Aerodynamic Drag ◽  
Flow Simulation ◽  
Improve Performance ◽  
Trailing Edge ◽  
Scale Models ◽  
Base Cavity ◽  
Improved Design ◽  
Helmet Design

Aerodynamic drag contributes the majority of the resistance experienced by a competitive cyclist. Low aerodynamic drag is a key quality of high performance equipment and many aerodynamic helmets have been developed. These helmets are designed with a teardrop shape that attempts to maintain attached air flow. This shape provides a drag reduction when the athlete has their head up and is looking forward but has adverse effects if the athlete rotates their head down. A helmet design that helps maintain attached airflow while presenting reduced frontal area when the athlete’s head is down could significantly improve performance. The aerodynamic improvements of applying a truncated airfoil shape with a trailing edge modification to a helmet design were investigated. SolidWorks Flow Simulation was used to evaluate the aerodynamic forces. A common production helmet design was progressively truncated to determine the optimal truncation length and the effects of multiple trailing edge modifications were tested. A specific truncation length with a trailing edge base cavity was found to provide similar head up performance but significantly better head down performance compared to the production design. Scale models of the final improved design and the production helmet were tested in the wind tunnel to verify the computational results.

Applying the high performance organisation framework in the horticulture and greenhouse sector

2017 ◽  
Vol 21 (2) ◽  
pp. 136-151 ◽  
Author(s):  
André de Waal ◽  
Alex Meingast
Keyword(s):  
High Performance ◽  
Design Methodology ◽  
Agricultural Sector ◽  
Questionnaire Data ◽  
Improve Performance ◽  
Content Type ◽  
Agricultural Enterprises ◽  
Study Results ◽  
Research Gap

Purpose The Dutch agricultural sector nowadays experiences many challenges. To deal with these, the sector has been interested in finding ways to improve performance. Mostly, the improvement research has concentrated in the areas of innovation of products and quality, supply chain management, cooperatives, entrepreneurship and human resources. However, hardly any research has been done into ways to strengthen the internal organisation, encompassing the quality of management, employees and processes and systems of the agriculture company. This paper aims to address this research gap by evaluating whether the high performance organisation (HPO) framework, a scientific validated analysis and improvement technique, can be used to help agricultural enterprises to strengthen their internal organisation. Design/methodology/approach The HPO Questionnaire was applied at four Dutch horticulture companies to evaluate their performance. Subsequently, at each company, interviews were held to obtain more information about the scores. Then, a workshop was organised with the management of all four companies to discuss the study results. Findings The workshop showed that the framework was suitable for the participating companies to start improving their organisations, as management of all four companies agreed that the analysis and recommendations, derived from analysing the questionnaire data and the interviews, were highly relevant to their business. Originality/value As there is no holistic organisational evaluation and improvement technique which looks specifically at the internal organisation of horticulture companies, available for the agricultural sector, the application of the HPO Framework in this sector is the first of its kind.

Assessment of the quality of opening of soil structures technical means developed in Kuban State Agrarian University

2020 ◽  
Author(s):  
B. F. Tarasenko B. F. ◽  
◽  
S. Y. Orlenko S. Y. ◽  
V. V. Kuzmin V. V.
Keyword(s):  
Comparative Analysis ◽  
Field Tests ◽  
Soil Structures ◽  
Improved Design

The article presents a comparative analysis, based on field tests, of the quality of loosening of soil structures of the upper horizon with technical means developed at KubSAU and an improved design of a universal tillage unit.

THE EFFECT OF PROCESSING METHODS ON THE NUTRITIONAL QUALITY OF AFRICAN BREADFRUITS (TRECULIA AFRICANA) SEEDS

2020 ◽  
Vol 16 (2) ◽  
pp. 60
Author(s):  
Nwozo Sarah Onyenibe ◽  
Julius Oluwaseun Oluwafunmilola ◽  
Stanley Udogadi Nwawuba
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Nutritional Quality ◽  
High Performance ◽  
Phytochemical Analysis ◽  
Mineral Contents ◽  
Processing Methods ◽  
African Breadfruit

The extracted seeds of African breadfruit are identified to be extremely healthy whenever it is correctly processed. Therefore, the aim of the present study was to evaluate the effects of processing methods on the nutritional quality of African breadfruit seed. A qualitative phytochemical analysis including: Alkaloid, Flavonoid, Saponin, Tannin, Anthraquinone, Terpenoids, Steroid, and Cardiac Glycosides for the different fraction of African breadfruit seed was performed using a standard method. The result revealed the presence and greater amount of phytochemical for the raw fraction; seven in eight, six in eight for steamed fraction, and four in eight for boiled and roasted respectively. Anti-nutrient, Proximate, and Mineral Content were also conducted using standard methods. The amino acid composition was determined using High-Performance Liquid Chromatography (HPLC). The results of the present study revealed that anti-nutrients including Phytate, Tannins, and Oxalate were significantly p<0.05 reduced in the boiled fraction 5.47±0.15, 3.42±0.02 and 6.89±0.05, and highest in the raw fraction 7.77±0.01, 5.09±0.03 and 9.34±0.14. The proximate composition including; percentage crude fat, Ash, Carbohydrate, Fatty acid, and Energy value were significantly lower p<0.05 in the boiled fraction relative to the other fractions. Mineral contents; calcium, magnesium, sodium, potassium, and phosphorus were also significantly p<0.05 elevated in the boiled fraction relative to the raw, steamed, and roasted fraction. The amino acid composition was highest in the roasted and boiled fraction 57.350 and 56.978, and lowest in the steamed and raw fraction 35.754 and 28.748 respectively. Therefore, boiling (cooking) is encouraged for the preparation of African breadfruit seed.

scholarly journals Dynamic Quality of an Aerostatic Thrust Bearing with a Microgroove and Support Center on Elastic Suspension

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1492
Author(s):  
Vladimir Kodnyanko ◽  
Stanislav Shatokhin ◽  
Andrey Kurzakov ◽  
Lilia Strok ◽  
Yuri Pikalov ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Negative Impact ◽  
Aerostatic Bearing ◽  
Elastic Suspension ◽  
Variable Parameters ◽  
Aerostatic Bearings ◽  
Improved Design ◽  
Dynamic Quality ◽  
Bearing Layer

The disadvantage of aerostatic bearings is their low dynamic quality. The negative impact on the dynamic characteristics of the bearing is exerted by the volume of air contained in the bearing gap, pockets, and microgrooves located at the outlet of the feeding diaphragms. Reducing the volume of air in the flow path is a resource for increasing the dynamic quality of the aerostatic bearing. This article presents an improved design of an axial aerostatic bearing with simple diaphragms, an annular microgroove, and an elastic suspension of the movable center of the supporting disk. A mathematical model is presented and a methodology for calculating the static characteristics of a bearing and dynamic quality indicators is described. The calculations were carried out using dimensionless quantities, which made it possible to reduce the number of variable parameters. A new method for solving linearized and Laplace-transformed boundary value problems for transformants of air pressure dynamic functions in the bearing layer was applied, which made it possible to obtain a numerical solution of problems sufficient for practice accuracy. The optimization of the criteria for the dynamic quality of the bearing was carried out. It is shown that the use of an elastic suspension of the support center improves its dynamic characteristics by reducing the volume of compressed air in the bearing layer and choosing the optimal volume of the microgroove.

scholarly journals New diagonal micropolarizer arrays designed by an improved model in fourier domain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jia Hao ◽  
Yan Wang ◽  
Kui Zhou ◽  
Xiaochang Yu ◽  
Yiting Yu
Keyword(s):  
Stokes Parameters ◽  
Fourier Domain ◽  
Extended Model ◽  
Reconstruction Accuracy ◽  
Polarization Imaging ◽  
New Class ◽  
Reconstruction Quality ◽  
Improved Design ◽  
Improved Model

AbstractThe design of micropolarizer array (MPA) patterns in Fourier domain provides an efficient approach to reconstruct and investigate the polarization information. Inspired by Alenin’s works, in this paper, we propose an improved design model to cover both 2 × N MPAs and other original MPAs, by which an entirely new class of MPA patterns is suggested. The performance of the new patterns is evaluated through Fourier domain analysis and numerical simulations compared with the existing MPAs. Particularly, we analyze the reconstruction accuracy of the first three Stokes parameters and degree of linear polarization (DoLP) in detail. The experimental results confirm that the 2 × 2 × 2 MPA provides the highest reconstruction quality of s0, s1, s2 and DoLP in terms of quantitative measures and visual quality, while the 3 × 3 diagonal MPA achieves the state-of-the-art best results in case of single-snapshot systems. The guidance of this extended model and new diagonal MPAs show its massive potential for the division of focal plane (DoFP) polarization imaging applications.

scholarly journals Dietary and Ergogenic Supplementation to Improve Elite Soccer Players’ Performance

2021 ◽  
pp. 1-7
Author(s):  
Haniel Fernandes
Keyword(s):  
Dietary Supplements ◽  
High Performance ◽  
Scientific Literature ◽  
Soccer Players ◽  
Competitive Sport ◽  
Beetroot Juice ◽  
Improve Performance ◽  
Sustained Release Tablets ◽  
High Level ◽  
Ergogenic Supplements

<b><i>Background:</i></b> Soccer is an extremely competitive sport, where the most match important moments can be defined in detail. Use of ergogenic supplements can be crucial to improve the performance of a high-performance athlete. Therefore, knowing which ergogenic supplements are important for soccer players can be an interesting strategy to maintain high level in this sport until final and decisive moments of the match. In addition, other supplements, such as dietary supplements, have been studied and increasingly referenced in the scientific literature. But, what if ergogenic supplements were combined with dietary supplements? This review brings some recommendations to improve performance of soccer athletes on the field through dietary and/or ergogenic supplements that can be used simultaneously. <b><i>Summary:</i></b> Soccer is a competitive sport, where the match important moments can be defined in detail. Thus, use of ergogenic supplements covered in this review can improve performance of elite soccer players maintaining high level in the match until final moments, such as creatine 3–5 g day<sup>−1</sup>, caffeine 3–6 mg kg<sup>−1</sup> BW around 60 min before the match, sodium bicarbonate 0.1–0.4 g kg<sup>−1</sup> BW starting from 30 to 180 min before the match, β-alanine 3.2 and 6.4 g day<sup>−1</sup> provided in the sustained-release tablets divided into 4 times a day, and nitrate-rich beetroot juice 60 g in 200 mL of water (6 mmol of NO3<sup>−</sup> L) around 120 min before match or training, including a combination possible with taurine 50 mg kg<sup>−1</sup> BW day<sup>−1</sup>, citrulline 1.2–3.4 g day<sup>−1</sup>, and arginine 1.2–6 g day<sup>−1</sup>. <b><i>Key Messages:</i></b> Soccer athletes can combine ergogenic and dietary supplements to improve their performance on the field. The ergogenic and dietary supplements used in a scientifically recommended dose did not demonstrate relevant side effects. The use of various evidence-based supplements can add up to further improvement in the performance of the elite soccer players.

scholarly journals Development and application of a spectrophotometric method in quality evaluation of benzimidazole anthelminthics in Nairobi city county

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Johnson K. Murage ◽  
Beatrice K. Amugune ◽  
Peter Njogu ◽  
Stanley Ndwigah
Keyword(s):  
Spectrophotometric Method ◽  
High Performance ◽  
Neglected Tropical Diseases ◽  
Developing Economies ◽  
Raw Materials ◽  
Poor Quality ◽  
Prolonged Treatment ◽  
Good Precision ◽  
Market Surveillance

Abstract Background Neglected tropical diseases (NTDs) are a group of communicable diseases which are prevalent in the tropics affecting more than one billion people. Treatment and prevention of these infections is very costly to developing economies. Helminthiases are classified among NTDs. The communities afflicted are poor and have limited access to essential resources for their livelihood. Poor-quality drugs for NTDs may lead to death or prolonged treatment without achieving the desired results. The limited resources used in purchasing poor-quality drugs will therefore be wasted instead of being put to good use. Most of the methods available for the analysis of benzimidazole anthelminthics utilize high-performance liquid chromatography. They are therefore time consuming, require sophisticated and expensive equipment, utilize rare and expensive reagents and solvents, and call for skilled personnel. A simple, rapid, and inexpensive ultraviolet spectrophotometric method of analysis would therefore come in handy especially in the analysis of many samples as occurs during post-authorization market surveillance for quality. Results The suitable solvent for the spectroscopic analysis was established as 0.1 M methanolic HCl. The wavelength of analysis was set at 294 nm. Upon validation, the method was found to have good linearity. The range over which linearity was established was way beyond the 80 to 120% of the working concentration specified by the ICH. The method exhibited good precision. Out of 32 commercial samples analyzed, five (15.6%) did not comply with compendial specifications. Intra-brand batch variation was also observed. Out of three batches of product A002T analyzed, one did not comply with compendial specifications. Conclusion A major limitation in the analysis of benzimidazole anthelminthics is the lack of reliable, simple, rapid, and low-cost methods of analysis with high throughput. The developed method serves to fill this gap. It can be used in the analysis of raw materials and finished products. It can also be used in the establishment of the quality of products prior to registration. The method will prove very useful in post-market surveillance of quality of benzimidazole anthelminthics.

scholarly journals A Review on Improved Design Techniques for High Performance Planar Waveguide Slot Arrays

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1311
Author(s):  
Giovanni Andrea Casula ◽  
Giuseppe Mazzarella ◽  
Giorgio Montisci ◽  
Giacomo Muntoni
Keyword(s):  
Planar Waveguide ◽  
High Performance ◽  
Order Effects ◽  
Waveguide Slot ◽  
Waveguide Bends ◽  
Radar Systems ◽  
Slot Arrays ◽  
Planar Array ◽  
Improved Design ◽  
Design Techniques

Planar waveguide slot arrays (WSAs) have been used since 1940 and are currently used as performing antennas for high frequencies, especially in applications such as communication and RADAR systems. We present in this work a review of the most typical waveguide slot array configurations proposed in the literature, describing their main limitations and drawbacks along with possible effective countermeasures. Our attention has been focused mainly on the improved available design techniques to obtain high performance WSAs. In particular, the addressed topics have been reported in the following. Partially filled WSAs, or WSAs covered with single or multilayer dielectric slabs, are discussed. The most prominent second-order effects in the planar array feeding network are introduced and accurately modeled. The attention is focused on the T-junction feeding the array, on the effect of interaction between each slot coupler of the feeding network and the radiating slots nearest to this coupler, and on the waveguide bends. All these effects can critically increase the first sidelobes if compared to the ideal case, causing a sensible worsening in the performance of the array.

Robust Environmental Sensing Using UAVs

2021 ◽  
Vol 2 (4) ◽  
pp. 1-20
Author(s):  
Ahmed Boubrima ◽  
Edward W. Knightly
Keyword(s):  
Air Pollution ◽  
Gas Sensors ◽  
High Performance ◽  
Weather Conditions ◽  
Ambient Air ◽  
Mission Planning ◽  
Pollution Monitoring ◽  
Compound Pollution ◽  
Planning Algorithm

In this article, we first investigate the quality of aerial air pollution measurements and characterize the main error sources of drone-mounted gas sensors. To that end, we build ASTRO+, an aerial-ground pollution monitoring platform, and use it to collect a comprehensive dataset of both aerial and reference air pollution measurements. We show that the dynamic airflow caused by drones affects temperature and humidity levels of the ambient air, which then affect the measurement quality of gas sensors. Then, in the second part of this article, we leverage the effects of weather conditions on pollution measurements’ quality in order to design an unmanned aerial vehicle mission planning algorithm that adapts the trajectory of the drones while taking into account the quality of aerial measurements. We evaluate our mission planning approach based on a Volatile Organic Compound pollution dataset and show a high-performance improvement that is maintained even when pollution dynamics are high.

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