scholarly journals Morphological adaptation of the calamistrum to the cribellate spinning process in Deinopoidae (Uloboridae, Deinopidae)

2016 ◽  
Vol 3 (2) ◽  
pp. 150617 ◽  
Author(s):  
Anna-Christin Joel ◽  
Ingo Scholz ◽  
Linda Orth ◽  
Peter Kappel ◽  
Werner Baumgartner

Spiders are famous for their silk with fascinating mechanical properties. However, some can further produce, process and handle nano fibres, which are used as capture threads. These ‘cribellate spiders’ bear a specialized setae comb on their metatarsus (calamistrum), which modifies cribellate nano fibres to assemble a puffy structure within the capture thread. Among different species, the calamistrum morphology can differ remarkably. Although a model of thread production has been established for Uloborus plumipes , it is not resolved if/how different shaped calamistra influence the production process. We were able to transfer the model without restrictions to spiders with different shaped calamistra. Fibres are not locked between setae but are passing across a rather smooth surface-like area on the calamistrum. This area can be relocated, explaining the first morphological difference between calamistra, without changing the influence of the calamistrum on fibres. By performing an elongated leg movement, contact between fibres and calamistrum could be adjusted after finishing thread production. This movement has to bring the thread in contact with the second morphological peculiarity: cribellate teeth. We suggest these teeth are used to handle the thread independently of the spinnerets, a feature only necessary for spiders, which do not move during web construction.

Author(s):  
Margret Weissbach ◽  
Marius Neugebauer ◽  
Anna-Christin Joel

AbstractSpider silk attracts researchers from the most diverse fields, such as material science or medicine. However, still little is known about silk aside from its molecular structure and material strength. Spiders produce many different silks and even join several silk types to one functional unit. In cribellate spiders, a complex multi-fibre system with up to six different silks affects the adherence to the prey. The assembly of these cribellate capture threads influences the mechanical properties as each fibre type absorbs forces specifically. For the interplay of fibres, spinnerets have to move spatially and come into contact with each other at specific points in time. However, spinneret kinematics are not well described though highly sophisticated movements are performed which are in no way inferior to the movements of other flexible appendages. We describe here the kinematics for the spinnerets involved in the cribellate spinning process of the grey house spider, Badumna longinqua, as an example of spinneret kinematics in general. With this information, we set a basis for understanding spinneret kinematics in other spinning processes of spiders and additionally provide inspiration for biomimetic multiple fibre spinning.


2019 ◽  
Vol 136 ◽  
pp. 02030
Author(s):  
Chen Dong ◽  
Chen Ming ◽  
Cai Ouyang ◽  
Li Pengkun

The GRC formwork structural column adopts the factory-based vertical prefabrication production process, which can reduce the floor space, reduce the formwork loss, speed up the construction progress, promote the full decoration of the prefabricated building, and improve the efficiency of the assembly construction. major. In order to optimize the production process of prefabricated GRC formwork column, the overall stress system of GRC formwork structure is analyzed in the concrete pouring process, and the thickness of GRC formwork, the number of steel hoops and the GRC mode are considered. The influence of the shell cross-section size on the mechanical properties. The research results can provide reference for the optimization and design of prefabricated GRC formwork column production process.


2011 ◽  
Vol 314-316 ◽  
pp. 1944-1947 ◽  
Author(s):  
Jozef Maščeník ◽  
Stefan Gaspar

Production of components, necessary for the construction of the machine resp. or device is a demanding manufacturing process. One of the possibilities of increasing efficiency and production quality is the introduction of unconventional technologies to the production process. Knowing the dependence of the impact of non-conventional technologies on the mechanical properties of products and their subsequent verification is an important aspect when designing and manufacturing them. The article deals with the impact of used unconventional technology, that means laser, plasma and water jet on the roughness of a cutting edge and microhardness of material S 355 J2 G3.


Author(s):  
N.N. Zagirov ◽  
Yu.N. Loginov ◽  
E.V. Ivanov ◽  
V.G. Kuz’min

The problem of chip processing of aluminum alloy containing scandium is considered. The difficulty of remelting due to easy oxidation of the alloy components is noted. It is proposed to dispose of the shavings without transferring the metal to liquid state. The aim of the work is to construct technological scheme for the processing of waste chips of the Al—Mg—Sc alloy formed as result of machining cast billets by cutting. Results of experiments including cold briquetting, hot extrusion and drawing are presented. The mechanical properties of the product obtained according to several variants of the technological scheme are measured. The possibility of continuous drawing of semi-finished product is shown. The conclusion is made about the possibility of using the scheme in the production process.


2011 ◽  
Vol 6 (3) ◽  
pp. 155892501100600 ◽  
Author(s):  
Eric Devaux ◽  
Carole Aubry ◽  
Christine Campagne ◽  
Maryline Rochery

Polylactide (PLA) was mixed with 4 wt.% of carbon nanotubes (CNTs) to produce electrical conductive multifilament yarns by melt spinning process for humidity detection. Thanks to a variation of electrical conductivity, this flexible sensor could detect the moisture presence. The introduction of plasticizer was necessary to ensure higher fluidity and drawability of the blend during the spinning process. The plasticizer modifies the crystallinity and the mechanical properties of the yarns. The effectiveness of this sensor (PLA/4 wt.% CNTs fibres) sensitive to humidity, is optimal when the spinning conditions are adapted. In this way, the temperature and the rate of the drawing roll were reduced. The influence of these parameters on the crystallinity, the mechanical properties and the sensitivity of the yarns were studied. Once the appropriate spinning conditions found, one humidity sensitive yarn was processed and the repeatability and efficient reversibility of its sensitivity were highlighted.


2015 ◽  
Vol 15 (1) ◽  
pp. 131-137 ◽  
Author(s):  
K. Buczkowska ◽  
T. Pacyniak

Abstract The aging granulate is to activate the blowing agent during the manufacturing process to granulate models can re-expand and shape the model of well-sintered granules, smooth surface and a suitable mechanical strength. The article presents the results of studies which aim was to determine the optimum time for aging pre-foamed granules for pre-selected raw materials. The testing samples were shaped in an autoclave, with constant parameters sintering time and temperature. Samples were made at 30 minute intervals. Models have been subjected to flexural strength and hardness.


Author(s):  
Hans-Christian Möhring ◽  
Dina Becker ◽  
Rocco Eisseler ◽  
Thomas Stehle ◽  
Tim Reeber

AbstractHybrid manufacturing processes are known for combining the advantages of additive manufacturing and more traditional manufacturing processes such as machining to create components of complex geometry while minimising material waste. The trend towards lightweight design, especially in view of e-mobility, gives aluminium materials an important role to play. This study examines the use of aluminium alloys in laser metal wire deposition (LMWD) processes with subsequent subtractive machining, which is considerably more difficult due to the different process-related influences. The investigations are focussed on the influence of the differently controlled laser power on the shape accuracy, the microstructure, and the hardness of the AlMg5 test components after the LMWD process with subsequent subtractive machining by turning. The long-term goal of the investigations is to increase the stability of the hybrid production process of AlMg5 components with defined dimensional accuracy and mechanical properties.


2021 ◽  
Vol 263 (4) ◽  
pp. 2708-2723
Author(s):  
Manuel Bopp ◽  
Arn Joerger ◽  
Matthias Behrendt ◽  
Albert Albers

Many concepts for acoustic meta materials rely on additive manufacturing techniques. Depending on the production process and material of choice, different levels of precision and repeatability can be achieved. In addition, different materials have different mechanical properties, many of which are frequency dependent and cannot easily be measured directly. In this contribution the authors have designed different resonator elements, which have been manufactured utilizing Fused Filament Fabrication with ABSplus and PLA, as well as PolyJet Fabrication with VeroWhitePlus. All structures are computed in FEA to obtain the calculated Eigenfrequencies and mode shapes, with the respective literature values for each material. Furthermore, the dynamic behavior of multiple instances of each structure is measured utilizing a 3D-Laser-Scanning Vibrometer under shaker excitation, to obtain the actual Eigenfrequencies and mode shapes. The results are then analyzed in regards to variance between different print instances, and in regards to accordance between measured and calculated results. Based on previous work and this analysis the parameters of the FEA models are updated to improve the result quality.


Author(s):  
Armando Lopes Ramalho ◽  
Agostinho da Silva ◽  
Marcelo Calvete Gaspar ◽  
Carlos Capela ◽  
Luis Celorrio-Barragué ◽  
...  

Within a pulp industry production process, a drop in the performance of a wood log rotary debarker was identified. Such loss of performance was due to the occurrence of excessive wear of the device's cutting blades, requiring their regular and premature replacement. The material used to manufacture the cutting blades, Hardox 500, has characteristics considered adequate for the required use. However, it was concluded that the blade manufacturing process degraded its mechanical properties, leading to its premature wear when placed in service. The present study intends to propose, characterize, and validate an alternative cutting process to manufacture the debarker's cutting blades. Abrasive waterjet cutting technology was proposed to produce the cutting blades. The suitability of this manufacturing process is discussed considering the specified geometry and the material characteristics of the resulting cutting blades.


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