scholarly journals Influence of Fiber Type on Fiberweb Properties in High-Speed Carding

2004 ◽  
Vol os-13 (2) ◽  
pp. 1558925004os-13
Author(s):  
N. B. Doguc ◽  
Abdelfattah M. Seyam ◽  
William Oxenham
Keyword(s):  
High Speed ◽  
Unit Area ◽  
Fiber Type ◽  
Fixed Number ◽  
Operating Conditions ◽  
Fiber Types ◽  
Novel Approach ◽  
General Data ◽  
Key Parameter

The performance of four different fiber types processed at two different carding speeds of 85 and 120 m/min, under fixed operating conditions, was assessed. The totally novel approach of fixing the fiber diameter was used in the experiments. To serve this purpose, we designed four different fibers. In addition, we fixed the number of fibers per unit area of the carded web so as to create constant carding conditions for all experimental fibers. The fixed number of fibers per unit area was achieved by carding the same number of fibers per unit time for a given speed. We took samples from different parts of the card and analyzed them in order to enumerate the effect of fiber type on cardability. Fiberweb uniformity was regarded as a key parameter for assessing the cardability. Several other web and fiber parameters were measured in order to augment the understanding of the role of fiber type in high-speed carding. In general, data revealed that fiberweb uniformity did not significantly differ among fiber types at the two carding speeds 85 m/min and 120 m/min.

The Role of Porous Media in Homogenization of High Pressure Diesel Fuel Spray Combustion

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Navid Shahangian ◽  
Damon Honnery ◽  
Jamil Ghojel
Keyword(s):  
High Pressure ◽  
Porous Media ◽  
High Speed ◽  
Fuel Spray ◽  
Compression Ignition Engines ◽  
System Pressure ◽  
Novel Approach ◽  
Air Mixing ◽  
The Media

Interest is growing in the benefits of homogeneous charge compression ignition engines. In this paper, we investigate a novel approach to the development of a homogenous charge-like environment through the use of porous media. The primary purpose of the media is to enhance the spread as well as the evaporation process of the high pressure fuel spray to achieve charge homogenization. In this paper, we show through high speed visualizations of both cold and hot spray events, how porous media interactions can give rise to greater fuel air mixing and what role system pressure and temperature plays in further enhancing this process.

Numerical Investigation of the Effects of Axial Cylinder Bore Profiles on Piston Ring Radial Dynamics

2003 ◽  
Vol 125 (4) ◽  
pp. 1081-1089 ◽  
Author(s):  
Y. Piao ◽  
S. D. Gulwadi
Keyword(s):  
High Speed ◽  
Piston Ring ◽  
Gasoline Engine ◽  
Engine Performance ◽  
Operating Conditions ◽  
Engine Oil ◽  
Oil Consumption ◽  
Ring Pack ◽  
Cylinder Bore

The role of cylinder bore shapes in engine performance has been the subject of several studies in recent years. In particular, the influence of bore distortion on oil consumption under high speed conditions has generated significant interest. In this paper, the effect of an axial bore profile on radial dynamics of a ring is investigated. Radial ring motions within grooves due to the axial bore profile can generate significant inertial effects and also have an impact on ring end-gap sizes and lubrication conditions at the ring-liner interfaces. The magnitude of such effects is dependent on the ring-pack configuration, engine operating conditions (speed and load) and axial bore profile details. These issues are investigated in this study due to their implication on engine oil consumption, friction and blow-by. The authors have developed an analytical expression to account for the effects of radial ring inertia due to an axial bore profile for implementation in a piston ring-pack simulation tool RINGPAK. Simulation results from a gasoline engine study are presented to illustrate the effects of engine speeds, ring tensions, and characteristics of axial bore profiles on ring radial dynamics and ring-liner lubrication. Relevant qualitative comparisons are made to experimental measurements available in the literature.

Numerical Investigation of the Effects of Axial Cylinder Bore Profiles on Piston Ring Radial Dynamics

2002 ◽  
Author(s):  
Y. Piao ◽  
S. D. Gulwadi
Keyword(s):  
High Speed ◽  
Piston Ring ◽  
Gasoline Engine ◽  
Engine Performance ◽  
Operating Conditions ◽  
Engine Oil ◽  
Oil Consumption ◽  
Ring Pack ◽  
Cylinder Bore

The role of cylinder bore shapes in engine performance has been the subject of several studies in recent years. In particular, the influence of bore distortion on oil consumption under high speed conditions has generated significant interest. In this paper, the effect of an axial bore profile on radial dynamics of a ring is investigated. Radial ring motions within grooves due to the axial bore profile can generate significant inertial effects and also have an impact on ring end-gap sizes and lubrication conditions at the ring-liner interfaces. The magnitude of such effects is dependent on the ring-pack configuration, engine operating conditions (speed and load) and axial bore profile details. These issues are investigated in this study due to their implication on engine oil consumption, friction and blow-by. The authors have developed an analytical expression to account for the effects of radial ring inertia due to an axial bore profile for implementation in a piston ring–pack simulation tool RINGPAK. Simulation results from a gasoline engine study are presented to illustrate the effects of engine speeds, ring tensions and characteristics of axial bore profiles on ring radial dynamics and ring-liner lubrication. Relevant qualitative comparisons are made to experimental measurements available in the literature.

scholarly journals Super-relaxed state of myosin in human skeletal muscle is fiber-type dependent

2020 ◽  
Author(s):  
Lien A. Phung ◽  
Aurora D. Foster ◽  
Mark S. Miller ◽  
Dawn A. Lowe ◽  
David D. Thomas
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Epifluorescence Microscopy ◽  
Model Organisms ◽  
Muscle Physiology ◽  
Fiber Types ◽  
Mhc I

AbstractThe myosin super-relaxed state (SRX) in skeletal muscle is hypothesized to play an important role in regulating muscle contractility and thermogenesis in humans, but has only been examined in model organisms. Here we report the first human skeletal muscle SRX measurements, using quantitative epifluorescence microscopy of fluorescent 2’/3’-O-(N-methylanthraniloyl) ATP (mantATP) single-nucleotide turnover. Myosin heavy chain (MHC) isoform expression was determined using gel electrophoresis for each permeabilized vastus lateralis fiber, to allow for novel comparisons of SRX between fiber-types. We find that the fraction of myosin in SRX is less in MHC IIA fibers than in MHC I and IIAX fibers (p = 0.008). ATP turnover of SRX is faster in MHC IIAX fibers compared to MHC I and IIA fibers (p = 0.001). We conclude that SRX biochemistry is measurable in human skeletal muscle, and our data indicate that SRX depends on fiber type as classified by MHC isoform. Extension from this preliminary work would provide further understanding regarding the role of SRX in human muscle physiology.

scholarly journals A Novel Study of Synthesis and Experimental Investigation on Hybrid Biocomposites for Biomedical Orthopedic Application

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
C. V. Subba Rao ◽  
R. Sabitha ◽  
P. Murugan ◽  
S. Rama Rao ◽  
K. Anitha ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Fiber Type ◽  
Natural Fibers ◽  
Weight Ratio ◽  
Dimensional Accuracy ◽  
Fiber Types ◽  
Shore Hardness ◽  
Novel Approach ◽  
Raster Angle ◽  
Feather Fiber

In recent years the biocomposites are highly utilized in the biomedical applications, due to excellent strength as well as weight ratio. A lot of natural fibers, namely, flax, hemp, jute, kenaf, and sisal are cheaply available in colossal amount. Aim of this study, a novel approach, is executed for construction of biomedical orthopedic parts by using mixture of natural fibers. This work handled biocomposites such as flax fiber (FX), chicken feather fiber (CF), kenaf fiber (KF), and rice husk fiber (RH) effectively. From all these composites, four sets of mixed fibers with reinforcement of polylactic acid polymer used for creating orthopedic parts. The hand-lay-based methodology is undertaken for preparation of hybrid biocomposites. Parameters involved for this study are fiber types (KF + RH, RH + FX, FX + CF, and CF + KF), laminate count (2, 4, 6 and 8) infill density (30%, 60%, 90%, and 120%), and raster angle (0/60, 30/120, 50/140, and 70/160). Finding of this work is dimensional accuracy, flexural strength, and shore hardness that are analyzed by L16 orthogonal array. ANOVA statistical analysis is enhanced and enlightens the results of flexural strength and source hardness of the biocomposites. Amongst in four parameters, the fiber type parameter extremely contributes such as 40.50% in the flexural analysis. Similarly, laminate count parameter highly contributes such as 31.01% in the shore hardness analysis.

Development of a Non-Contacting Mechanical Seal for High Performance Turbocharger Applications

2018 ◽  
Author(s):  
Daniel A. Nelson
Keyword(s):  
High Speed ◽  
High Performance ◽  
Piston Ring ◽  
Fuel Efficiency ◽  
Thermal Response ◽  
Operating Conditions ◽  
Mechanical Seal ◽  
Tribological Surfaces ◽  
Novel Approach ◽  
Automobile Engines

This paper presents the design and development of a non-contacting dry-gas mechanical seal for high performance automotive turbocharger applications. Turbochargers are increasingly being incorporated into high performance automobile engines to improve fuel efficiency, enhance energy recovery, and increase horsepower as compared with similar sized naturally aspirated engines. Minimizing the wear rate of tribological surfaces in the turbomachinery is critical to maximizing the reliability and durability of the turbocharger. A dry-gas seal for turbochargers and related technologies with 2 to 4 cm shafts has been developed. The seal provides a complete barrier between the bearing oil and compressor flow path and is capable of reverse pressure and high speed. The seal performance was evaluated for speeds between 60,000 to 80,000 RPM, pressure differentials between −0.8 (reverse pressure) to 6 bar, and temperatures between 20 to 200 °C. Structural and thermal response of the seal components to the operating conditions are analyzed using finite element methods and the tribological behavior of the seal rings are analyzed using computational fluid dynamics. The design is experimentally validated in a seal test stand. This novel approach reduces turbocharger blowby and shows no measurable wear when compared with piston ring seals.

Adenosine exerts a glycogen-sparing action in contracting rat skeletal muscle

1997 ◽  
Vol 272 (5) ◽  
pp. E762-E768 ◽  
Author(s):  
L. Vergauwen ◽  
E. A. Richter ◽  
P. Hespel
Keyword(s):  
Skeletal Muscle ◽  
Glycogen Synthase ◽  
Fiber Type ◽  
Fiber Types ◽  
Adrenergic Stimulation ◽  
Receptor Antagonism ◽  
Glycogen Synthase Activity ◽  
Glycogen Sparing ◽  
Glycogen Breakdown

The role of adenosine in regulating glycogen breakdown during electrically induced muscle contractions was investigated in isolated rat hindquarters perfused with a standard medium either lacking or containing 100 microU/ml insulin and/or 1.67 nM isoprenaline. Nonselective A1/A2-adenosine receptor antagonism via caffeine enhanced (P < 0.05) glycogen breakdown in contracting fast-oxidative (FO) fibers by 40%, provided they were exposed to both insulin and isoprenaline. Combined A1/A2-receptor antagonism by 8-cyclopentyl-1,3-dipropylxanthine (CPDPX) plus 3,7-dimethyl-1-proparglyxanthine (DMPX) fully reproduced (P < 0.05) this stimulatory effect. Furthermore, CPDPX plus DMPX also enhanced (P < 0.05) glycogenolysis during contractions in soleus but not in white gastrocnemius muscle. In contrast, CPDPX or DMPX alone did not affect glycogenolysis in either fiber type. Muscle adenosine 3',5'-cyclic monophosphate concentration during contractions was increased (P < 0.05) by CPDPX plus DMPX in both fiber types, whereas glycogen synthase fractional activity was depressed (P < 0.05). Phosphorylase activity was not changed by CPDPX plus DMPX. It is concluded that adenosine exerts a glycogen-sparing action in oxidative skeletal muscle exposed to both insulin and beta-adrenergic stimulation during contraction, presumably via stimulation of glycogen synthase activity.

Viscous Throughflow Modeling of Axial Compressor Bladerows Using a Tangential Blade Force Hypothesis

1998 ◽  
Vol 120 (4) ◽  
pp. 662-670 ◽  
Author(s):  
S. J. Gallimore
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Boundary Layer Flows ◽  
Quick Method ◽  
Novel Approach ◽  
Performance Predictions ◽  
Additional Losses

This paper describes the modeling of axial compressor blade rows in an axisymmetric viscous throughflow method. The basic method, which has been reported previously, includes the effects of spanwise mixing, using a turbulent diffusion model, and endwall shear within the throughflow calculation. The blades are modeled using a combination of existing two-dimensional blade performance predictions for loss and deviation away from the annulus walls and a novel approach using tangential blade forces in the endwall regions. Relatively simple assumptions about the behavior of the tangential static pressure force imposed by the blades allow the secondary deviations produced by tip clearance flows and the boundary layer flows at fixed blade ends to be calculated in the axisymmetric model. Additional losses are assigned in these regions based on the calculated deviations. The resulting method gives realistic radial distributions of loss and deviation across the whole span at both design and off-design operating conditions, providing a quick method of estimating the magnitudes of these effects in the preliminary design process. Results from the method are compared to measured data in low and high-speed compressors and multistage three-dimensional viscous CFD predictions.

Development of a Noncontacting Mechanical Seal for High Performance Turbocharger Applications

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Daniel A. Nelson
Keyword(s):  
High Speed ◽  
High Performance ◽  
Piston Ring ◽  
Fuel Efficiency ◽  
Thermal Response ◽  
Operating Conditions ◽  
Mechanical Seal ◽  
Tribological Surfaces ◽  
Novel Approach ◽  
Automobile Engines

This paper presents the design and development of a noncontacting dry-gas mechanical seal for high performance automotive turbocharger applications. Turbochargers are increasingly being incorporated into high performance automobile engines to improve fuel efficiency, enhance energy recovery, and increase horsepower as compared with similar sized naturally aspirated engines. Minimizing the wear rate of tribological surfaces in the turbomachinery is critical to maximizing the reliability and durability of the turbocharger. A dry-gas seal for turbochargers and related technologies with 2–4 cm shafts has been developed. The seal provides a complete barrier between the bearing oil and compressor flow path and is capable of reverse pressure and high speed. The seal performance was evaluated for speeds between 60,000 and 80,000 rpm, pressure differentials between −0.8 (reverse pressure) to 6 bar, and temperatures between 20 and 200 °C. Structural and thermal response of the seal components to the operating conditions are analyzed using finite element methods and the tribological behavior of the seal rings are analyzed using computational fluid dynamics. The design is experimentally validated in a seal test stand. This novel approach reduces turbocharger blowby and shows no measurable wear when compared with piston ring seals.

Resistance to Ca2+-induced opening of the permeability transition pore differs in mitochondria from glycolytic and oxidative muscles

2008 ◽  
Vol 295 (2) ◽  
pp. R659-R668 ◽  
Author(s):  
Martin Picard ◽  
Kristina Csukly ◽  
Marie-Eve Robillard ◽  
Richard Godin ◽  
Alexis Ascah ◽  
...  
Keyword(s):  
Citrate Synthase ◽  
Fiber Type ◽  
Physiological Mechanism ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Fiber Types ◽  
Cyclophilin D ◽  
Novel Approach ◽  
Voltage Dependent ◽  
Ptp Opening

This study determined whether susceptibility to opening of the permeability transition pore (PTP) varies according to muscle phenotype represented by the slow oxidative soleus (Sol) and superficial white gastrocnemius (WG). Threshold for Ca2+-induced mitochondrial Ca2+ release following PTP opening was determined with a novel approach using permeabilized ghost myofibers. Threshold values for PTP opening were approximately threefold higher in fibers from WG compared with those from Sol (124 ± 47 vs. 30.4 ± 6.8 pmol Ca2+/mU citrate synthase). A similar phenomenon was also observed in isolated mitochondria (threshold: 121 ± 60 vs. 40 ± 10 nmol Ca2+/mg protein in WG and Sol), indicating that this was linked to differences in mitochondrial factors between the two muscles. The resistance of WG fibers to PTP opening was not related to the expression of putative protein modulators (cyclophilin D, adenylate nucleotide translocator-1, and voltage-dependent anion channels) or to difference in respiratory properties and occurred despite the fact that production of reactive oxygen species, which promote pore opening, was higher than in the Sol. However, endogenous matrix Ca2+ measured in mitochondria isolated under resting baseline conditions was approximately twofold lower in the WG than in the Sol (56 ± 4 vs. 111 ± 11 nmol/mg protein), which significantly accounted for the resistance of WG. Together, these results reveal fiber type differences in the sensitivity to Ca2+-induced PTP opening, which may constitute a physiological mechanism to adapt mitochondria to the differences in Ca2+ dynamics between fiber types.

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