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You searched for subject:(helmet angle). Showing records 1 – 3 of 3 total matches.

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University of Manchester

1. Zahid, Bilal. Riot helmet shells with continuous reinforcement for improved protection.

Degree: PhD, 2011, University of Manchester

The present research aims to develop a novel technique for creation of composite riot helmet shells with reinforcing fibre continuity for better protection against low velocity impacts. In this research an innovative, simple and effective method of making a single-piece continuously textile reinforced helmet shell by vacuum bagging has been established and discussed. This technique also includes the development of solid collapsible moulding apparatus from non-woven fibres. Angle-interlock fabric due to its good mouldability, low shear rigidity and ease of production is used in this research. Several wrinkle-free single- piece composite helmet shells have been manufactured. Low-velocity impact test on the continuously reinforced helmet shells has been carried out. For this purpose an in-house helmet shell testing facility has been developed. Test rig has been designed in such a way that the impact test can be carried out at different locations at the riot helmet shell. Low-velocity impact test has been successfully conducted on the developed test rig. The practical experimentation and analysis revealed that the helmet shell performance against impact is dependent on the impact location. The helmet shell top surface has better impact protection as compared to helmet shell side and back location. Moreover, the helmet shell side is the most at risk location for the wearer. Finite Element models were created and simulated in Abaqus software to investigate the impact performance of single-piece helmet shells at different impact locations. Models parts have been designed in Rhinoceros software. Simulated results are validated by the experimental result which shows that the helmet top position is the safest position against an impact when it is compared to helmet back and helmet side positions.

Subjects/Keywords: 687.162; Riot Helmet Shells, Continuous Textile Reinforcement, Angle-interlock Fabric, Textile Composites, Vacuum Bagging, Drop Weight, Low Velocity Impact, FEA, FE Simulation and ABAQUS.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Zahid, B. (2011). Riot helmet shells with continuous reinforcement for improved protection. (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/riot-helmet-shells-with-continuous-reinforcement-for-improved-protection(ef2e889d-28c0-42b7-8fd6-20b290e1563e).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551357

Chicago Manual of Style (16th Edition):

Zahid, Bilal. “Riot helmet shells with continuous reinforcement for improved protection.” 2011. Doctoral Dissertation, University of Manchester. Accessed January 18, 2021. https://www.research.manchester.ac.uk/portal/en/theses/riot-helmet-shells-with-continuous-reinforcement-for-improved-protection(ef2e889d-28c0-42b7-8fd6-20b290e1563e).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551357.

MLA Handbook (7th Edition):

Zahid, Bilal. “Riot helmet shells with continuous reinforcement for improved protection.” 2011. Web. 18 Jan 2021.

Vancouver:

Zahid B. Riot helmet shells with continuous reinforcement for improved protection. [Internet] [Doctoral dissertation]. University of Manchester; 2011. [cited 2021 Jan 18]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/riot-helmet-shells-with-continuous-reinforcement-for-improved-protection(ef2e889d-28c0-42b7-8fd6-20b290e1563e).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551357.

Council of Science Editors:

Zahid B. Riot helmet shells with continuous reinforcement for improved protection. [Doctoral Dissertation]. University of Manchester; 2011. Available from: https://www.research.manchester.ac.uk/portal/en/theses/riot-helmet-shells-with-continuous-reinforcement-for-improved-protection(ef2e889d-28c0-42b7-8fd6-20b290e1563e).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551357


University of Gothenburg / Göteborgs Universitet

2. Lord, Hans. Morphological antipredator adaptations in water fleas.

Degree: 2009, University of Gothenburg / Göteborgs Universitet

Some Bosmina and Daphnia species have the ability to develop extreme morphological antipredator defences, such as long antennules, high carapaces and helmets. The relative sizes of these plastic traits may differ substantially between populations, and also between individuals within a population, between sexes and during ontogeny. In this thesis I examine how abiotic factors (trophic levels and temperature) and biotic factors (fish and invertebrate predators) affect the size and shape of these traits. In the first two studies, calculations based on experimental results using physical morphological models sinking in glycerine, were used to estimate body drag and energy consumption in Bosmina. Eubosmina longispina, with a low carapace and short antennules, and Eubosmina coregoni gibbera, with a very high carapace and long antennules, were examined. At 5○C, E. c. gibbera had 32-45 % higher body drag than E. longispina. At 20○C the difference was 20-45 %. A model of swimming predicted that, all else being equal, this difference should result in 18-20 % (at 5○C) or 14-16 % (at 20○C) lower swimming speed for E. c. gibbera than for E. longispina. This indicates substantial hydrodynamic costs of the morphological antipredator defences, particularly in low temperatures. The morphological antipredator defences in E. c. gibbera are larger and more variable in females than in males. Male models had lower body drag than models of asexual and sexual females, suggesting that males can swim 14-28 % faster with the same energy consumption. High speed video documentation of swimming E. c. gibbera showed that males advanced 55-73 % further than females in each swimming stroke. Hydrodynamic body drag may therefore have significant implications for swimming and evolution of sexual dimorphism in water fleas. Males may lack the defensive, but hydrodynamically expensive, high carapace of female E. c. gibbera probably because competition over mates favours low body drag. The morphology and size of heads and trunks in Daphnia cristata individuals were studied in twenty lakes in the same drainage basin. The lakes showed a variation in lake total phosphorus and in densities of invertebrate predators and fish. In the end of the summer D. cristata had varying shape and size of their heads. Our results indicate that D. cristata, in nutrient rich lakes, show adaptive morphological defences against both visually hunting and size limited predators. Female D. cristata head shape, in the examined lakes, varied from small and rounded to large and curved. A significant positive correlation between lake total phosphorus and the allometric head coefficients was found, suggesting that the most extremely shaped heads are found in nutrient-rich lakes.

Subjects/Keywords: Body drag; Daphnia cristata; Reynolds number; viscosity; zooplankton; Bosmina; swimming velocity; cyclomorphosis; sexual dimorphism; head area; helmet angle; trophic condition; allometry; invertebrate predator; fish

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Lord, H. (2009). Morphological antipredator adaptations in water fleas. (Thesis). University of Gothenburg / Göteborgs Universitet. Retrieved from http://hdl.handle.net/2077/21030

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Lord, Hans. “Morphological antipredator adaptations in water fleas.” 2009. Thesis, University of Gothenburg / Göteborgs Universitet. Accessed January 18, 2021. http://hdl.handle.net/2077/21030.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Lord, Hans. “Morphological antipredator adaptations in water fleas.” 2009. Web. 18 Jan 2021.

Vancouver:

Lord H. Morphological antipredator adaptations in water fleas. [Internet] [Thesis]. University of Gothenburg / Göteborgs Universitet; 2009. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2077/21030.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Lord H. Morphological antipredator adaptations in water fleas. [Thesis]. University of Gothenburg / Göteborgs Universitet; 2009. Available from: http://hdl.handle.net/2077/21030

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

3. Zahid, Bilal. Riot Helmet Shells with Continuous Reinforcement for Improved Protection.

Degree: 2012, University of Manchester

The present research aims to develop a novel technique for the creation of composite riot helmet shells with reinforcing fibre continuity for better protection against low velocity impacts. In this research an innovative, simple and effective method of making a single-piece continuous textile reinforced helmet shell using vacuum bagging has been established and discussed. This technique also includes the development of solid collapsible moulding apparatus from nonwoven fibres. Angle-interlock fabric, due to its good mouldability, low shear rigidity and ease of production is used in this research. Several wrinkle-free single-piece composite helmet shells have been manufactured.Low-velocity impact tests on the continuously reinforced helmet shells have been carried out. For this purpose an in-house helmet shell testing facility has been developed. A test rig has been designed in such a way that the impact test can be carried out at different locations on the riot helmet shell. Low-velocity impact testing has been successfully conducted on the developed test rig. Practical experimentation and analysis revealed that the helmet shell performance against impact is dependent on the impact location. The helmet shell top surface has better impact protection as compared to the helmet shell side and back locations. Moreover, the helmet shell side is the most at risk location for the wearer. Finite Element models were created and simulated in Abaqus software to investigate the impact performance of single-piece helmet shells at different impact locations. Model parts have been designed in Rhinoceros software. Simulated results are validated by the experimental results which show that the helmet top position is the safest position against an impact when it is compared to the helmet back and helmet side positions.

The present research aims to develop a novel technique for the creation of composite riot helmet shells with reinforcing fibre continuity for better protection against low velocity impacts. In this research an innovative, simple and effective method of making a single-piece continuous textile reinforced helmet shell using vacuum bagging has been established and discussed. This technique also includes the development of solid collapsible moulding apparatus from nonwoven fibres. Angle-interlock fabric, due to its good mouldability, low shear rigidity and ease of production is used in this research. Several wrinkle-free single-piece composite helmet shells have been manufactured.Low-velocity impact tests on the continuously reinforced helmet shells have been carried out. For this purpose an in-house helmet shell testing facility has been developed. A test rig has been designed in such a way that the impact test can be carried out at different locations on the riot helmet shell. Low-velocity impact testing has been successfully conducted on the developed test rig. Practical experimentation and analysis revealed that the helmet shell performance against impact is dependent on the impact location. The helmet shell top…

Advisors/Committee Members: Chen, Xiaogang.

Subjects/Keywords: Riot Helmet Shells; Continuous Textile Reinforcement; Angle-interlock Fabric; Textile Composites; Vacuum Bagging; Drop Weight; Low Velocity Impact; FEA; FE Simulation and ABAQUS.

…manufacture 5-8-28 angle-interlock fabric for helmet development; 2) to develop flat composite… …method of making single-piece riot helmet shells from angle-interlock fabric using a vacuum… …43 Figure 2-8 Riot Helmet Assembly… …46 Figure 2-10 Half side of a typical multi-piece composite riot helmet shell… …52 Figure 2-12 Coverage area of the head by the visor and the helmet… 

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Zahid, B. (2012). Riot Helmet Shells with Continuous Reinforcement for Improved Protection. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:154722

Chicago Manual of Style (16th Edition):

Zahid, Bilal. “Riot Helmet Shells with Continuous Reinforcement for Improved Protection.” 2012. Doctoral Dissertation, University of Manchester. Accessed January 18, 2021. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:154722.

MLA Handbook (7th Edition):

Zahid, Bilal. “Riot Helmet Shells with Continuous Reinforcement for Improved Protection.” 2012. Web. 18 Jan 2021.

Vancouver:

Zahid B. Riot Helmet Shells with Continuous Reinforcement for Improved Protection. [Internet] [Doctoral dissertation]. University of Manchester; 2012. [cited 2021 Jan 18]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:154722.

Council of Science Editors:

Zahid B. Riot Helmet Shells with Continuous Reinforcement for Improved Protection. [Doctoral Dissertation]. University of Manchester; 2012. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:154722

.