scholarly journals Manufacturing of amber particles suitable for composite fibre melt spinning

2016 ◽  
Vol 70 (2) ◽  
pp. 51-57
Author(s):  
Inga Ļ Ļašenko ◽  
Sergejs Gaidukovs ◽  
Jūlija Rombovska
Keyword(s):  
Melt Spinning ◽  
Chemical Structure ◽  
Polyamide 6 ◽  
Polyamide Fibre ◽  
Ball Mills ◽  
Composite Fibre ◽  
Before And After ◽  
The Matrix ◽  
Average Size ◽  
Experimental Findings

Abstract Polyamide fibre containing amber particles was fabricated. The amber particles were obtained by grinding technology using planetary ball-mills. Scanning electron microscopy and granulometry testing were used to characterise the structure and the size of prepared amber particles. Fourier transform infrared spectroscopy was used to analyse the chemical structure of the amber particles. The amber particles were characterised with average size up to 3 μm. The chemical composition of amber before and after the grinding remained unchanged. The amber particles were melt-extruded using polyamide 6 as the matrix. Melt spinning processing was used to fabricate polyamide-amber filaments. Pre-oriented yarns and fully drawn yarns were obtained after hotdrawing experiments. Reported experimental findings of amber composite fibre could be important for textile applications.

scholarly journals Insect secretion on Albazia tree as biobased material alternative for matrix composite

2010 ◽  
Vol 7 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Jamasri Jamasri ◽  
B. R. Heru Santoso ◽  
J. P. Gentur Sutapa
Keyword(s):  
Matrix Composite ◽  
Bonding Strength ◽  
Chemical Structure ◽  
Solid Phase ◽  
Matrix Phase ◽  
Heating Process ◽  
Evaporation Process ◽  
Before And After ◽  
The Matrix

Investigation and characterization of insect secretion on Albazia tree (hereinafter used the term ISA) showed that the material contained of complex molecules with the main constituent is aleuretic acid and the insect is lac. So ISA is secretion of lac insect on Albazia tree. This paper will report the biobased ISA as a feasible matrix for composite. Some requirements of the ISA matrix to protect the fibers, keeping the fibers in place and can distribute the load to the fibers, the first step was the matrix phase changed from solid to liquid with an ethanol as a solvent so the matrix distributed to cover the fibers perfectly. Secondly, the matrix phase then change into solid by evaporation process to remove ethanol solvent without any scattered to the fibers. This matrix is now called as matrix lac (or matlac). Characterization of chemical structure of the matlac investigated before and after mixed with ethanol using FTIR method. Evaporation process of ethanol was also examined and conducted by heating the sample respectively 40, 50, 70, 90, 110, 150 and 180 oC for 2-210 minutes to determine the weight loss and changes liquid to solid phase. TGA also used to determine performance of the matrix at high temperatures. Evaluation of fiber-matrix bonding strength was done by wettability testing. The results showed that the ISA can be used as a matrix composite by blending ethanol as a main solvent followed by melting and heating process at temperatures above 100oC. Chemical structure of the ISA before and after the mixing of ethanol did not change that ethanol has a function as a “transporter“ to bring ISA reaches the matrix requiretments. Bonding strength between the fiber and the matlac showed contact angle of about 30o and indicated good wettability. Average of the tensile strength of the matlac was 7 MPa which has opportunity and feasibility to be developed further as matrix composite. Method proposes succesed making composite from matlac matrix.

Application of amber filler for production of novel polyamide composite fiber

2016 ◽  
Vol 86 (20) ◽  
pp. 2127-2139 ◽  
Author(s):  
Sergejs Gaidukovs ◽  
Inga Lyashenko ◽  
Julija Rombovska ◽  
Gerda Gaidukova
Keyword(s):  
Melt Spinning ◽  
Polyamide 6 ◽  
Composite Fiber ◽  
Composite Fibers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Medical Textiles ◽  
Time Scanning ◽  
New Type ◽  
Average Size

The present investigation is connected to the field of medical textiles, which includes the development and application of composite fibers. The aim of the paper is the processing and investigation of polyamide 6 (PA6)–amber composite fibers. The use of amber filler for the preparation of a new type of polymer composite fiber is described in detail for the first time. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and granulometry testing were used to test the structure and the size of the prepared amber particles. The obtained amber particles were characterized by an average size of up to 3 µm and a regular shape. Fourier transform infrared (FTIR) spectroscopy investigations showed that amber in the dispersed state does not change its chemical structure and contains one of the active compounds—succinic acid. The effect of the amber filler inclusion on the melt-spinning routes of fully drawn yarns (FDY) and pre-oriented yarns (POY) was determined. Amber composite fibers general use is medical fabric (compression socks and tights); it is biocompatible with skin cells.

Tem analysis of multiple-energy arsenic implanted and Rta'd silicon

1987 ◽  
Vol 45 ◽  
pp. 246-247
Author(s):  
R.A. Herring
Keyword(s):  
Device Fabrication ◽  
High Concentration ◽  
Tem Analysis ◽  
Defect Clusters ◽  
High Fluences ◽  
Small Defect ◽  
Before And After ◽  
The Matrix ◽  
The Difference ◽  
Factor Type

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.

Radiolabeled r-Hirudin as a Measure of Thrombin Activity at, or within, the Rabbit Aorta Wall In Vitro and In Vivo

1994 ◽  
Vol 71 (04) ◽  
pp. 499-506 ◽  
Author(s):  
Mark W C Hatton ◽  
Bonnie Ross-Ouellet
Keyword(s):  
Rabbit Aorta ◽  
Balloon Injury ◽  
Recombinant Hirudin ◽  
Aorta Wall ◽  
Thrombin Activity ◽  
Before And After ◽  
The Matrix

SummaryThe behavior of 125I-labeled recombinant hirudin towards the uninjured and de-endothelialized rabbit aorta wall has been studied in vitro and in vivo to determine its usefulness as an indicator of thrombin activity associated with the aorta wall. Thrombin adsorbed to either sulfopropyl-Sephadex or heparin-Sepharose bound >95% of 125I-r-hirudin and the complex remained bound to the matrix. Binding of 125I-r-hirudin to the exposed aorta subendothelium (intima-media) in vitro was increased substantially if the tissue was pre-treated with thrombin; the quantity of l25I-r-hirudin bound to the de-endothelialized intima-media (i.e. balloon-injured in vitro) correlated positively with the quantity of bound 131I-thrombin (p <0.01). Aortas balloon-injured in vivo were measured for thrombin release from, and binding of 125I-r-hirudin to, the de-endothelialized intimal surface in vitro; 125I-r-hirudin binding correlated with the amount of active thrombin released (p <0.001). Uptake of 125I-r-hirudin by the aorta wall in vivo was proportional to the uptake of 131I-fibrinogen (as an indicator of thrombin activity) before and after balloon injury. After 30 min in the circulation, specific 125I-r-hirudin binding to the uninjured and de-endo- thelialized (at 1.5 h after injury) aorta wall was equivalent to 3.4 (± 2.5) and 25.6 (±18.1) fmol of thrombin/cm2 of intima-media, respectively. Possibly, only hirudin-accessible, glycosaminoglycan-bound thrombin is measured in this way.

Novel Electro Polymerization Method to Synthesized Anti-corrosion Coated Layer on Stainless Steel Surface from (N-Benzothiazolyl Maleamic Acid) and Study its Biological Activity

2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Muna I Khalaf ◽  
Khulood A Saleh ◽  
Khalil S Khalil
Keyword(s):  
Stainless Steel ◽  
Chemical Structure ◽  
Inhibition Efficiency ◽  
Steel Plate ◽  
Polymeric Coating ◽  
Stainless Steel Surface ◽  
Plate Electrode ◽  
Before And After ◽  
Maleamic Acid ◽  
Polymerization Method

Electro polymerization of N-benzothiazolyl maleamic acid (NBM) was carried out on stainless steel plate electrode in a protic medium of monomer aqueous solution using electrochemical oxidation procedure in electrochemical cell.Spectroscopic characterization techniques were investigated to obtain information about the chemical structure of polymer. The anti-corrosion action of polymer was investigated on stainless steel by electrochemical polarization method. In addition, the effect of adding nanomaterial (TiO2, ZnO (bulk-nano)) to monomer solution on the corrosion behavior of stainless steel was investigated. The results obtained showed that the corrosion rate of S-steel increased with temperature increase from 293K to 323K and the values of inhibition efficiency by coating polymer increase with nanomaterial addition. Apparent energies of activation have been calculated for the corrosion process of S-steel in acidic medium before and after polymeric coating. Furthermore were studied the effect of the preparing polymer on some strain of bacteria.

A pilot study on the effect of ulipristal acetate on myoma angiogenesis, measured by 2D ultrasound and VEGF serum levels

2020 ◽  
pp. 19-29
Author(s):  
Patricia Diaz Ortega ◽  
Manuel García Manero
Keyword(s):  
Pilot Study ◽  
Power Doppler ◽  
Uterine Fibroids ◽  
Premenopausal Women ◽  
Serum Levels ◽  
Ulipristal Acetate ◽  
Before And After ◽  
Angiogenesis Process ◽  
2D Ultrasound ◽  
Average Size

Introduction: Symptomatic uterine fibroids can cause symptoms that can be disabling. There are many treatments, including ulipristal acetate, whose role in reducing symptoms and decreasing the size of the fibroid is well known. With this preliminary study, we also try to evaluate the correlation between myoma vascularization measured by ultrasound (Power Doppler 2D) and serum VEGF levels, before and after treatment with ulipristal acetate; in patients diagnosed with symptomatic uterine fibroids. Materials and Methods: A preliminary, prospective observational pilot study was designed. Twenty-four premenopausal women, diagnosed with symptomatic uterine fibroids, were included and all of them completed the study. Four cycles of ulipristal acetate were administered according to the dose and indications specified in the data sheet. In order to assess the influence of this treatment on the angiogenesis process of the fibroids, measurements of VEGF serum levels were made and their vascularization was assessed by means of 2D power doppler ultrasound; at the beginning and the end of treatment. In addition, several determinations of the same parameters were made throughout the successive visits. Endpoints were defined as the decrease in VEGF levels from previous levels, the decrease in myoma vascularization on ultrasound, and the reduction in myoma size. Result: 24 patients who met the inclusion criteria were enrolled (n=24). The average size of myomas was reduced from 45,08 ? 24,02mm to 29?16,96mm after treatment. The average VEGF serum level significantly decreased after the first treatment cycle (from 147,17 ? 153,51 pg/ml to 102,04 ? 186,08pg/ml). Vascularization of myomas after treatment with ulipristal acetate was analyzed, and a significantly decrease was achieved in 83,3% of cases. Conclusion: There is a correlation between myoma vascularization and treatment with Ulipristal acetate. SPRMs may provide effective treatment for women with symptomatic fibroids by two ways: supports selective progesterone receptor modulators and reduced angiogenesis. Keywords: Angiogenesis; Ulipristal Acetate; Uterine fibroids; VEGF

Preschoolers’ imitation of sentential complement sentences: Does the nature of the matrix clause matter?

2021 ◽  
pp. 014272372110242
Author(s):  
Ian Morton ◽  
C. Melanie Schuele
Keyword(s):  
Language Development ◽  
Age Group ◽  
Matrix Clause ◽  
Developmental Progression ◽  
Main Effect ◽  
Dependent Variables ◽  
The Matrix ◽  
Group 3 ◽  
Sentence Imitation ◽  
Experimental Findings

Preschoolers’ earliest productions of sentential complement sentences have matrix clauses that are limited in form. Diessel proposed that matrix clauses in these early productions are propositionally empty fixed phrases that lack semantic and syntactic integration with the clausal complement. By 4 years of age, however, preschoolers produce sentential complement sentences with matrix clauses that are more varied. Diessel proposed that the matrix clauses in these later productions semantically and syntactically embed the complement clause. We refer to these matrix clauses as formulaic and true, respectively. Diessel’s hypothesis about the development of sentential complement sentences was based on an analysis of spontaneous language. The purpose of this study was to evaluate Diessel’s hypothesis with an experimental sentence imitation task wherein stimuli varied in the nature of the matrix clause. Thirty children with typical language development participated; 10 children in each age group (3-, 4-, and 5-year-olds) imitated 50 sentential complement sentences that included either a true or a formulaic matrix clause; the structure of the dependent clauses did not vary. Dependent variables were percent sentence imitation and percent matrix clause imitation. There was a significant main effect for matrix clause type on imitation of sentences and matrix clauses. There was also a significant main effect for age on imitation of sentences and matrix clauses. Significant matrix clause type-by-age interactions were such that percent sentence imitation and percent matrix clause imitation varied by age. Three- and 4-year-olds were less proficient than 5-year-olds on imitation of sentences with true matrix clauses and on imitations of true matrix clauses. Only 3- and 4-year-olds were less proficient imitating true matrix clauses than formulaic matrix clauses. Experimental findings support Diessel’s hypothesis that there is a developmental progression in the nature of preschoolers’ production of sentential complement sentences.

scholarly journals Influence of Alumina Nanofibers Sintered by the Spark Plasma Method on Nickel Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Strength Properties ◽  
Alumina Nanoparticles ◽  
Metal Powders ◽  
Wide Range ◽  
The Matrix ◽  
Spark Plasma ◽  
Average Size

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.

Intraventricular injection of antibodies to β1-integrins generates pressure gradients in the brain favoring hydrocephalus development in rats

2009 ◽  
Vol 297 (5) ◽  
pp. R1312-R1321 ◽  
Author(s):  
Gurjit Nagra ◽  
Lena Koh ◽  
Isabelle Aubert ◽  
Minhui Kim ◽  
Miles Johnston
Keyword(s):  
Fluid Pressure ◽  
Active Role ◽  
Intraventricular Injection ◽  
Pressure Gradients ◽  
Tissue Pressure ◽  
Before And After ◽  
The Matrix ◽  
System 2 ◽  
Periventricular Area ◽  
The Brain

In some tissues, the injection of antibodies to the β1-integrins leads to a reduction in interstitial fluid pressure, indicating an active role for the extracellular matrix in tissue pressure regulation. If perturbations of the matrix occur in the periventricular area of the brain, a comparable lowering of interstitial pressures may induce transparenchymal pressure gradients favoring ventricular expansion. To examine this concept, we measured periventricular (parenchymal) and ventricular pressures with a servo-null micropipette system (2-μm tip) in adult Wistar rats before and after anti-integrin antibodies or IgG/IgM isotype controls were injected into a lateral ventricle. In a second group, the animals were kept for 2 wk after similar injections and after euthanization, the brains were removed and assessed for hydrocephalus. In experiments in which antibodies to β1-integrins ( n = 10) but not isotype control IgG/IgM ( n = 7) were injected, we observed a decline in periventricular pressures relative to the preinjection values. Under similar circumstances, ventricular pressures were elevated ( n = 10) and were significantly greater than those in the periventricular interstitium. We estimated ventricular to periventricular pressure gradients of up to 4.3 cmH2O. In the chronic preparations, we observed enlarged ventricles in many of the animals that received injections of anti-integrin antibodies (21 of 29 animals; 72%) but not in any animal receiving the isotype controls. We conclude that modulation/disruption of β1-integrin-matrix interactions in the brain generates pressure gradients favoring ventricular expansion, suggesting a novel mechanism for hydrocephalus development.

Comparative study of thermoplastic liner materials with regard to mechanical and permeation barrier properties before and after cyclic thermal aging

2021 ◽  
Vol 63 (4) ◽  
pp. 311-316
Author(s):  
Simon Backens ◽  
Jan Siering ◽  
Stefan Schmidt ◽  
Nikolai Glück ◽  
Wilko Flügge
Keyword(s):  
Thermal Aging ◽  
Barrier Properties ◽  
Tensile Tests ◽  
Polyamide 6 ◽  
Pressure Vessels ◽  
Cross Linking ◽  
Polyamide 12 ◽  
Type Iv ◽  
Before And After ◽  
Permeation Properties

Abstract Lightweight pressure vessels of type IV for hydrogen storage consist of a thermoplastic inner liner, commonly from polyethylene or polyamide. The liner is the permeation barrier against the compressed gas and must prevent the formation of cracks, also after temperature changes, for example after refueling processes. In the present work high-density polyethylene, cross-linked polyethylene, polyamide 6 and polyamide 12 were characterized by tensile tests, single notch impact tests and permeations measurements before and after a cyclic thermal aging process. The aging only lead to slight changes of mechanical properties due to post-crystallization, but to a significant decrease of permeation properties. This decrease was contributed to weakened, amorphous regions where chain splitting occurred. Considerable differences in properties resulted from different peroxide cross-linking times of polyethylene at the same temperature. A longer holding time at 200 °C led to an improvement in impact strength by a factor of more than three. However, the permeation properties decreased by about 50 %, indicating that peroxide cross-linking in the melt inhibited the formation of crystalline regions.

Sign in / Sign up

Export Citation Format

Share Document