scholarly journals Using Weighing and Counting in Measuring Yarn Diameter Deter Mining Yarn Volumetric Density.(Dept.T)

2021 ◽  
Vol 26 (3) ◽  
pp. 10-19
Author(s):  
Hamdy Ebraheem ◽  
Urs Meyer
Keyword(s):  
Volumetric Density ◽  
Yarn Diameter

scholarly journals Emerging Technology for a Green, Sustainable Energy Promising Materials for Hydrogen Storage, from Nanotubes to Graphene—A Review

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2499
Author(s):  
Krzysztof Jastrzębski ◽  
Piotr Kula
Keyword(s):  
Energy Source ◽  
Hydrogen Storage ◽  
Mobile Applications ◽  
Emerging Technology ◽  
Green Energy ◽  
Point Of View ◽  
Energy Industry ◽  
Volumetric Density ◽  
Potential Use ◽  
Carbon Based

The energetic and climate crises should pose a challenge for scientists in finding solutions in the field of renewable, green energy sources. Throughout more than two decades, the search for new opportunities in the energy industry made it possible to observe the potential use of hydrogen as an energy source. One of the greatest challenges faced by scientists for the sake of its use as an energy source is designing safe, usable, reliable, and effective forms of hydrogen storage. Moreover, the manner in which hydrogen is to be stored is closely dependent on the potential use of this source of green energy. In stationary use, the aim is to achieve high volumetric density of the container. However, from the point of view of mobile applications, an extremely important aspect is the storage of hydrogen, using lightweight tanks of relatively high density. That is why, a focus of scientists has been put on the use of carbon-based materials and graphene as a perspective solution in the field of H2 storage. This review focuses on the comparison of different methods for hydrogen storage, mainly based on the carbon-based materials and focuses on efficiently using graphene and its different forms to serve a purpose in the future H2-based economy.

scholarly journals Development of an Additive Manufacturing System for the Deposition of Thermoplastics Impregnated with Carbon Fibers

2019 ◽  
Vol 3 (2) ◽  
pp. 35 ◽  
Author(s):  
Miguel Reis Silva ◽  
António M. Pereira ◽  
Nuno Alves ◽  
Gonçalo Mateus ◽  
Artur Mateus ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Additive Manufacturing ◽  
Carbon Fibers ◽  
Low Cost ◽  
Deposition Process ◽  
Processing Parameters ◽  
Yarn Diameter ◽  
Thermoplastic Matrix ◽  
Anisotropic Mechanical Properties ◽  
Long Carbon Fiber

This work presents an innovative system that allows the oriented deposition of continuous fibers or long fibers, pre-impregnated or not, in a thermoplastic matrix. This system is used in an integrated way with the filamentary fusion additive manufacturing technology and allows a localized and oriented reinforcement of polymer components for advanced engineering applications at a low cost. To demonstrate the capabilities of the developed system, composite components of thermoplastic matrix (polyamide) reinforced with pre-impregnated long carbon fiber (carbon + polyamide), 1 K and 3 K, were processed and their tensile and flexural strength evaluated. It was demonstrated that the tensile strength value depends on the density of carbon fibers present in the composite, and that with the passage of 2 to 4 layers of fibers, an increase in breaking strength was obtained of about 366% and 325% for the 3 K and 1 K yarns, respectively. The increase of the fiber yarn diameter leads to higher values of tensile strength of the composite. The obtained standard deviation reveals that the deposition process gives rise to components with anisotropic mechanical properties and the need to optimize the processing parameters, especially those that lead to an increase in adhesion between deposited layers.

Estimation of Central Osteopenia in Children With Chronic Polyarthritis Treated With Glucocorticoids

PEDIATRICS ◽  
1993 ◽  
Vol 91 (6) ◽  
pp. 1127-1130
Author(s):  
Antero Kotaniemi ◽  
Anneli Savolainen ◽  
Hannu Kautiainen ◽  
Heikki Kröger
Keyword(s):  
Bone Mineral Density ◽  
Lumbar Spine ◽  
Femoral Neck ◽  
Bone Mineral ◽  
Bone Size ◽  
Mineral Density ◽  
Volumetric Density ◽  
Chronic Polyarthritis ◽  
The Mean ◽  
Bone Volumetric Density

Study objective. To investigate the degree and determinants of osteopenia in juvenile chronic polyarthritis. Design. Retrospective case-control study of central bone mineral density. Setting. Rheumatism Foundation Hospital and Kuopio University Hospital, Finland. Subjects. A sample of 43 girls aged 7 to 19 with juvenile chronic polyarthritis treated with systemic glucocorticoids and a control sample of 44 healthy girls matched for age. Main outcome measures. Bone mineral density and bone size (width) measured by dual-energy x-ray absorptiometry and bone volumetric density calculated as an approximation of true bone density at both the lumbar spine and femoral neck. Results. The girls with juvenile chronic arthritis had reduced bone mineral density, bone size, and bone volumetric density at both the lumbar spine and femoral neck (statistically significant findings, P = .022 for the bone size of the femoral neck and P < .001 for the other parameters). At the spine, the mean bone mineral density was 80%, the mean bone size 89%, and the mean bone volumetric density 89% of the values in the control group. At the femoral neck, the values were 78%, 93%, and 83%, respectively. The groups were matched for age, but the girls with arthritis were smaller and lighter. In the juvenile arthritis group, the femoral bone mineral density and bone volumetric density and the spinal bone width correlated negatively with the mean glucocorticoid dose. Conclusion. Axial bone mineral density is clearly reduced in severe juvenile polyarthritis and is mediated by both decreased bone volumetric density and diminished growth.

scholarly journals Effects of a Randomized Weight Loss Intervention Trial in Obese Adolescents on Tibia and Radius Bone Geometry and Volumetric Density

2018 ◽  
Vol 33 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Jennifer C Kelley ◽  
Nicolas Stettler-Davis ◽  
Mary B Leonard ◽  
Douglas Hill ◽  
Brian H Wrotniak ◽  
...  
Keyword(s):  
Weight Loss ◽  
Bone Geometry ◽  
Weight Loss Intervention ◽  
Intervention Trial ◽  
Obese Adolescents ◽  
Volumetric Density

A study of tubular braided structure with negative Poisson’s ratio behavior

2017 ◽  
Vol 88 (24) ◽  
pp. 2810-2824 ◽  
Author(s):  
Ning Jiang ◽  
Hong Hu
Keyword(s):  
Poisson’S Ratio ◽  
Structural Parameters ◽  
Uniaxial Extension ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Yarn Diameter ◽  
Wrap Angle ◽  
Negative Poisson's Ratio ◽  
Braided Structure ◽  
Braiding Angle

Textile structures with negative Poisson’s ratio (PR) behavior are called auxetic textile structures. They have received increasing attention in recent years and have been designed and fabricated through spinning, knitting, weaving and non-woven methods. However, auxetic textile structures fabricated using braiding method have not been reported so far. This paper reported a novel type of auxetic braided structure based on a helical structural arrangement. The geometry of the structure and its deformation mechanism were first introduced and described. Then a special manufacturing process was developed by the modification of commonly used tubular braiding technology. Various auxetic braids were fabricated with different structural parameters and yarns and tested under uniaxial extension conditions. The results showed that all manufactured braids exhibited high negative PR behavior and maintained this behavior until the fracture of the component wrap yarn. Among three structural parameters discussed, namely wrap angle, braiding angle and braiding yarn diameter, the wrap angle had more effects on the tensile properties of auxetic braided structure than the other two parameters. The success of fabricating auxetic braids with commercially available yarns in this study provides an alternative way to manufacture auxetics from positive PR materials.

scholarly journals Hydrogen Adsorbents with High Volumetric Density: New Materials and System Projections

2019 ◽  
Author(s):  
Donald J. Siegel ◽  
◽  
Alauddin Ahmed ◽  
Yiyang Liu ◽  
Adam Matzger ◽  
...  
Keyword(s):  
New Materials ◽  
Volumetric Density

scholarly journals Somatic genetics of CDR3 control TCR V-domain rotational probability and germline CDR2 scanning of polymorphic MHC

2021 ◽  
Author(s):  
Joseph Murray
Keyword(s):  
Major Histocompatibility Complex ◽  
T Cell ◽  
Genetic Linkage ◽  
Alpha Helix ◽  
Volumetric Density ◽  
Mhc Ii ◽  
Histocompatibility Complex ◽  
Hla Dr ◽  
Hla Dq ◽  
Relative Affinity

Abstract The mechanism which adapts the T-cell antigen receptor (TCR) within a given major histocompatibility complex (MHC/HLA) genotype is essential for protection against pathogens. Historically attributed to relative affinity, genetically vast TCRs are surprisingly focused towards a micromolar affinity for their respective peptide (p) plus MHC (pMHC) ligands. Thus, the somatic diversity of the TCR with respect to MHC-restriction, and (ultimately) to pathogens, remains enigmatic. Here, we derive a triple integral solution (from fixed geometry) for any given V domain in TCR bound to pMHC. Solved complexes involving HLA-DR and HLA-DQ, where genetic linkage to the TCR is most profound, were examined in detail. Certain V domains displayed rare geometry within this panel—specifying a restricted rotational probability/volumetric density (dV). Remarkably, hydrogen (H) bond charge-relays distinguished these structures from the others; suggesting that CDR3 binding chemistry dictates CDR2 contacts on the opposite MHC-II alpha helix. Together, these data suggest that TCR recapitulate dV and specialise target pMHC recognition, i.e., a dynamics alternative to a relative TCR-affinity based mechanism.

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