Investigating the braiding parameters and their effects on the mechanical and frictional properties of silk sutures

2021 ◽  
pp. 152808372110551
Author(s):  
Natarajan Sivanesan ◽  
Rameshbabu Venugopal ◽  
Ariharasudhan Subramanian
Keyword(s):  
Research Work ◽  
Silk Suture ◽  
Optimum Conditions ◽  
Frictional Properties ◽  
Handling Characteristics ◽  
Twist Level ◽  
Braided Structure ◽  
Braiding Angle ◽  
Silk Filament ◽  
Central Composite

In this research work, the simultaneous effects of braided sutures made up of silk filament were studied with respect to parameters such as filament twist (0-6 Twist/inch), braiding angle (28.8°–34.8°) and braid structure (1/1, 1/2 and 2/2) on tensile strength, elongation, bending stiffness and friction were investigated by using response surface methodology. The influence of independent and dependent values has been studied using the categorical central composite design of experiments. The optimum conditions for enhanced handling characteristics of braided silk suture were 3.7 twist /inch of silk filament twist level, at a 28.8°braid angle, and a 1/2 braided structure. The handling characteristics of the suture can be enhanced by choosing suitable braiding parameters.

scholarly journals Leaching and solvent extraction purification of zinc from Mehdiabad complex oxide ore

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Faraz Soltani ◽  
Hossna Darabi ◽  
Reza Aram ◽  
Mahdi Ghadiri
Keyword(s):  
Solvent Extraction ◽  
Environmental Pollution ◽  
Central Composite Design ◽  
Complex Oxide ◽  
Hydrometallurgical Process ◽  
Purification Process ◽  
Optimum Conditions ◽  
Leaching Experiments ◽  
Central Composite ◽  
Sulphuric Acid Concentration

AbstractAn integrated hydrometallurgical process was used for the zinc leaching and purification from a zinc ore containing 9.75 wt% zinc. The zinc minerals in the ore were hemimorphite, willemite, and calcophanite. Main gangue minerals were quartz, goethite, hematite, and calcite. Central composite design (CCD) method was used to design leaching experiments and the optimum conditions were found as follows: 30% of solid fraction, 22.05% sulphuric acid concentration, and the leaching temperature of 45 °C. The PLS containing 35.07 g/L zinc, 3.16 g/L iron, and 4.58 g/L manganese impurities was produced. A special purification process including Fe precipitation and Zn solvent extraction was implemented. The results showed that after precipitation of iron, Zn extraction of 88.5% was obtained with the 2 stages extraction system composed of 30 vol% D2EHPA as extractant. The overall Zn recovery from the ore was 71.44%. Therefore, an appropriate solution containing 16.6 g/L Zn, 0.05 g/L Fe, and 0.11 g/L Mn was prepared for the electro-winning unit without using the roasting and calcination steps (conventional method), which result in environmental pollution.

Kaempferol Extraction from Cuscuta reflexa using Supercritical Carbon Dioxide and Separation of Kaempferol from the Extracts

2011 ◽  
Vol 7 (4) ◽  
Author(s):  
Pranabendu Mitra ◽  
Kyu -Seob Chang ◽  
Dae-Seok Yoo
Keyword(s):  
Supercritical Co2 ◽  
Extraction Process ◽  
Optimum Conditions ◽  
Supercritical Co2 Extraction ◽  
Independent Variables ◽  
Cuscuta Reflexa ◽  
Optimal Processing ◽  
Layer Chromatography ◽  
Temperature Time ◽  
Central Composite

Kaempferol, a strong antioxidant, was extracted from Cuscuta reflexa (a medicinal plant) using supercritical CO2 and separated using thin-layer chromatography, column chromatography and HPLC analysis. A rotatable central composite design was used to determine the influence of process variables and arrive at optimal processing conditions in the supercritical CO2 extraction process of kaempferol. The kaempferol yield was effectively modelled as a function of the independent variables (temperature, time and pressure). The kaempferol yield increased with the increasing of temperature and time and decreasing of pressure of the supercritical CO2 extraction process. The predicted kaempferol yield at the optimum point was 52.92 µg/g and the optimum conditions were 50.7°C for 132.6 min and 15.9 MPa.

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.

Deriving an empirical formula to determine the optimum level of false-twist in mechanically-crimped textured polyester yarn

2011 ◽  
Vol 81 (19) ◽  
pp. 1995-2005 ◽  
Author(s):  
Tasnim N Shaikh ◽  
Someswar S Bhattacharya
Keyword(s):  
Torsional Rigidity ◽  
Research Work ◽  
Polynomial Equation ◽  
Transformation Process ◽  
Optimum Level ◽  
Mathematical Tool ◽  
Polyester Yarn ◽  
Wide Range ◽  
Twist Level ◽  
False Twist

Flat polyester yarn is bulked by the mechanical crimp texturizing process. The magnitude of the false-twist, introduced together with the torsional rigidity of the supply yarn, has a significant effect on the transformation process. The torsional rigidity of the supply yarn is in turn influenced by its fineness and bending characteristics. It is therefore deemed necessary to establish a mathematical relationship between the optimum false-twist level and the yarn fineness for materials with known bending characteristics. Such a relationship may help in producing a yarn with optimum bulk properties, while minimizing resource utilization and waste generation. This paper reports research work done in this direction. Polyester yarn is chosen for this investigation as it has a wide range of applications. Fully drawn multifilament polyester yarns, with different linear densities, are textured on a single-head mechanical crimp texturing machine. The results are analysed with the help of polynomial curve fitting (Polyfit) using MATLAB. This mathematical tool facilitated the derivation of the desired formula (polynomial equation) for the calculation of optimum false-twist level for fully drawn multifilament polyester yarns undergoing mechanical crimp texturizing.

Numerical Modeling of Braided Composites Using Energy Method

2014 ◽  
Author(s):  
Xiuli Shen ◽  
Longdong Gong
Keyword(s):  
Numerical Modeling ◽  
Fixed Points ◽  
Fiber Bundle ◽  
Calculation Error ◽  
Control Points ◽  
Braided Composites ◽  
Modeling Approach ◽  
Braided Structure ◽  
Braiding Angle ◽  
Woven Structure

Based on the braiding process and force analysis of yarn, a mesoscopic numerical modeling approach was established, which divided the modeling process as follows: establishing the control points according to the braiding process, establishing the fixed points during jamming, adjusting the control points after jamming, changing the position of fiber bundle due to the fiber bundle intertwined each other and establishing the fiber bundle trajectory according to the minimum strain energy. In the process of adjusting the intertwined fiber bundle trajectories, the fiber bundle trajectory was scattered. Using extrapolation adjustment method, discrete points of fiber bundle trajectory intertwined were adjusted in turn from the control points to the fixed points. Adjusted discrete points were equivalent at the corresponding location points of the corresponding trajectory, and at the same time, there was non-interference between the fiber bundle trajectories. Using this method, fiber bundle trajectory and cross section of the models of 2-D woven and 3-D four-directional braided composite materials were established, compared with the experiment result, which were consistent with the electronic microscope scan images and calculated woven structure size was in agreement with the measured data. The maximum relative calculation error of braiding bitch of 3-D four-directional braided structure was about 5%, especially braiding angle was 21° or so, the relative calculation error was below 2%. The maximum relative calculation error of surface braiding angle of 3-D four-directional braided structure was about 4%, especially braiding angle was 21° or so, the relative calculation error was below 2.4%. This modeling approach was fundamental for further analysis of the micromechanical strength and life of braided composites, which was applied to aero-engine hot section.

scholarly journals Galacto-oligosaccharides Production Using Permeabilized Cells of Kluyveromyces marxianus

2010 ◽  
Vol 6 (6) ◽  
Author(s):  
Ana Paula Manera ◽  
Fátima Aparecida de Almeida Costa ◽  
Maria Isabel Rodrigues ◽  
Susana Juliano Kalil ◽  
Francisco Maugeri Filho
Keyword(s):  
Kluyveromyces Marxianus ◽  
Enzyme Concentration ◽  
Human Intestine ◽  
Central Composite Rotatable Design ◽  
Optimum Conditions ◽  
Permeabilized Cells ◽  
Lactose Concentration ◽  
Optimized Conditions ◽  
Central Composite ◽  
Stimulation Of

Galacto-oligosaccharides are non-digestible carbohydrates and are recognized as important prebiotics for than stimulation of the proliferation of lactic acid bacteria and bifidobacteria in the human intestine. GOS can be produced by a transgalactosylation reaction catalysed by ?-galactosidase enzyme, and microorganisms can be used as a source of ?-galactosidase. In this work, a process for producing GOS using permeabilized cells of Kluyveromyces marxianus CCT 7082 was proposed. The effects of the concentrations of lactose and enzyme, temperature and pH were studied using a fractional design followed by a central composite rotatable design. The optimum conditions for galacto-oligosaccharides production were found to be: lactose concentration 500 g/L, enzyme concentration 10 U/mL, 45°C and pH 7.0. Under optimized conditions, the GOS concentration, yield and productivity were 83 g/L, 16.5% and 27.6 g/L.h, respectively.

scholarly journals Mespilus germanica (MG) and Tribulus terrestris (TT) Used as Biosorbents for Lead Removal from Aqueous Solutions: Adsorption Kinetics and Mechanisms

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Majid Ehteshami ◽  
Hamidreza Zolfaghari ◽  
Marjan Salari ◽  
Ehsan Teymouri
Keyword(s):  
Aqueous Solutions ◽  
Correlation Coefficient ◽  
Lead Removal ◽  
Tribulus Terrestris ◽  
Optimum Conditions ◽  
Effective Parameters ◽  
Lead Adsorption ◽  
Proposed Model ◽  
Central Composite ◽  
Solution Volume

Today, most countries around the globe are facing water resources restrictions, and it is predicted freshwater resources will be more valuable than oil wells in the next century. In the present study, the ability of lead removal using both powders of Mespilus germanica (MG) and Tribulus terrestris (TT) seeds and optimization of the adsorption process have been investigated. Four main parameters were selected for experimental design, namely, pH, time of contact, the ratio of adsorbent to solution volume, and initial concentration of lead in solution, and the optimization of effective parameters on lead adsorption was performed based on central composite design (CCD) under response surface methodology (RSM). According to the statistical results, the proposed model for MG and TT is confirmed with 0.95 and 0.96 correlation coefficient and 0.92 and 0.94 adjusted correlation coefficient, respectively. The results of parameter optimization also showed that both adsorbents have the acceptable ability to adsorb lead from aqueous solutions. Under the optimum conditions with the initial lead concentration of 10 mg/l, MG powder had better performance in lead adsorption of 96.04%, and TT powder also had an acceptive performance of 93.20%. Moreover, the MG and TT adsorbents have the most accordance with the Freundlich and D-R isotherms, respectively.

scholarly journals Optimasi Konsentrasi Etanol Dan Perbandingan Bahan Dengan Etanol Terhadap Aktivitas Antioksidan Ekstrak Daun Beluntas (Pluchea Indica Less) Menggunakan Response Surface Methodology (RSM)

2021 ◽  
Vol 10 (1) ◽  
pp. 1
Author(s):  
I Gusti Ngurah Bagus Pranantha Bistara K ◽  
I Ketut Suter ◽  
Gusti Ayu Kadek Diah Puspawati
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Ethanol Concentration ◽  
Dry Weight ◽  
Total Flavonoid Content ◽  
Optimum Conditions ◽  
Flavonoid Content ◽  
Tannin Content ◽  
Two Factors ◽  
Central Composite

The research was conducted to obtain the optimum of ethanol concentration and comparison of material with ethanol to produced beluntas leaves extract that had the highest antioxidant activiy. Response Surface Methodology (RSM) was used for optimization of extraction conditions with experimental design was a Central Composite Design (CCD) in two factors, namely ethanol concentration and comparison of material with ethanol. The results showed that the optimum conditions of beluntas leaves extraction were at ethanol concentration 62.71% and the comparison of material with ethanol 1:10.14. In this condition, the highest antioxidant activity was obtained at 65.80% with IC50, extract yield, total flavonoid content, and total tannin content were 3.87 ppm, 18.20% dry weight extract, 47.05 mg QE/g dry weight extract, and 9.11 mg TAE/g dry weight extract, respectively.

Improved handling characteristics of off-road vehicles by applying active control of steering wheel torque

2011 ◽  
Vol 2 (1) ◽  
pp. 66-74
Author(s):  
J. Kis ◽  
L. Jánosi
Keyword(s):  
Active Control ◽  
Research Work ◽  
Rear Wheel ◽  
Steering Wheel ◽  
Road Vehicles ◽  
Vehicle Handling ◽  
Handling Characteristics ◽  
Driving Speed ◽  
Wheel Torque ◽  
High Center

Driving speed of agricultural mobile machines have been increased in the recent years, raisingserious questions about vehicle handling characteristics considering the high center-of-gravity, multi-massconfiguration and rear-wheel-steering of these vehicles. The next generation of steering systems on offroad vehicles will incorporate a steering column mechatronic subsystem which will generate tactilefeedback for operator. This paper presents our research work to utilize steering wheel torque to improveoff-road vehicle handling characteristics.

Sign in / Sign up

Export Citation Format

Share Document