Synthetic imogolite: properties, synthesis and possible applications

Clay Minerals ◽  
1983 ◽  
Vol 18 (4) ◽  
pp. 459-472 ◽  
Author(s):  
V. C. Farmer ◽  
M. J. Adams ◽  
A. R. Fraser ◽  
F. Palmieri
Keyword(s):  
Mechanical Stability ◽  
Surface Acidity ◽  
Outer Diameter ◽  
Charged Colloids ◽  
Inner Surface ◽  
Forming Characteristics ◽  
Inner Diameter ◽  
Anionic Detergents ◽  
Positively Charged ◽  
Long Chain

AbstractThe unique properties of imogolite are closely related to its structure, which is a tube of 23–27 Å outer diameter and ∼10 Å inner diameter, with an AIOH outer surface and SiOH inner surface. Acid dispersions contain the long, positively-charged tubes as isolated units or small bundles, which form bulky gels in alkali, and flocculate with negatively-charged colloids, polyvalent anions, and long-chain anionic detergents. Sorption properties are associated with the 10 Å intra-tube pores and with inter-tube channels of variable dimensions. Surface acidity is less than that of layer-silicate clays. The chemical and mechanical stability, biological activity, film- and fibre-forming characteristics, and conditions of synthesis are reviewed, on the basis of both new and published findings. Areas of potential application are indicated.

scholarly journals Morphological Changes in Lamellar Macular Holes According to SD-OCT Examination over a Long Observation Period

Diagnostics ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1145
Author(s):  
Magdalena Kal ◽  
Izabela Chojnowska-Ćwiąkała ◽  
Mateusz Winiarczyk ◽  
Monika Jasielska ◽  
Jerzy Mackiewicz
Keyword(s):  
Retinal Thickness ◽  
Morphological Changes ◽  
Outer Diameter ◽  
Corrected Visual Acuity ◽  
Macular Holes ◽  
Kolmogorov Smirnov ◽  
Inner Diameter ◽  
Observation Period ◽  
Sd Oct

Background: The aim of this study was to evaluate the quantitative morphological changes in lamellar macular holes (LMHs) based on SD-OCT examinations and to assess the correlations among minimal retinal thickness (MRT), reading vision (RV), and best corrected visual acuity (BCVA) over a 36-month follow-up period. Methods: A group of 40 patients (44 eyes) with LMH was evaluated, with an average age of 69.87 (SD = 10.14). The quantitative parameters monitored in the follow-up period (at 0, 3, 6, 12, 18, 24, 30, and 36 months) were tested for normality of distribution by Shapiro–Wilk and Kolmogorov–Smirnov tests. Results: The RV and BCVA values were stable, and no significant changes were found at any of the check-ups during the 36-month follow-up period (BCVA p = 0.435 and RV p = 0.0999). The analysis of individual quantitative LMH parameters during the 36-month follow-up period did not demonstrate statistically significant differences: MRT (p = 0.461), Max RT temporal (p = 0.051), Max RT nasal (p = 0.364), inner diameter (ID) (p = 0.089), and outer diameter (OD) (p = 0.985). Conclusions: The observations at 0, 6, 12, 18, 24, 30, and 36 months revealed moderate and significant correlations between RV and MRT. No significant correlation between BCVA and MRT was observed.

Influence of fully submerged permanent magnets in the evaluation of heat transfer and performance analysis of single slope glass solar still

2021 ◽  
pp. 095765092110310
Author(s):  
Ajay Kumar Kaviti ◽  
Akkala Siva Ram ◽  
Amit Kumar Thakur
Keyword(s):  
Heat Transfer ◽  
Permanent Magnets ◽  
Outer Diameter ◽  
Solar Still ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Inner Diameter ◽  
Evaporative Heat Transfer ◽  
And Performance ◽  
Depth Water

In this experimental study, permanent magnets with three different sizes (M-1: 32 mm inner diameter, 70 mm outer diameter and 15 mm thick, M-2: 25 mm inner diameter, 60 mm outer diameter and 10 mm thick, M-3: 22 mm inner diameter, 45 mm outer diameter and 9 mm thick) are fully submerged in the single-slope glass solar still. The performance of magnetic solar stills (MSS) with three different sizes at 2 cm depth water to ensure that magnets are fully submerged is compared with conventional solar still (CSS) at the location 17.3850°N, 78.4867°E. Tiwari model is adapted to calculate the heat transfer coefficients (HTC), internal and exergy efficiencies. MSS with M-1, M-2 and M-3 significantly enhanced the convective, radiative, and evaporative heat transfer rate for the 2 cm depth of water. This is due to the desired magnetic treatment of water, which reduces the surface tension and increases the hydrogen bonds. The MSS's total internal HTC, instantaneous efficiencies led CSS by 25.52%, 28.8%, respectively, with M-1. Having various magnetic fields due to different magnets sizes increases MSS's exergetic efficiency by 33.61% with M-1, 33.76% with M-2, and 42.25% with M-3. Cumulative yield output for MSS with M-1, M-2, and M-3 is 21.66%, 17.64%, 15.78% higher than CSS. The use of permanent magnets of different sizes in the MSS is a viable, economical and straight forward technique to enhance productivity.

Shell Body Nose Forming by Rotary Swaging Process

2011 ◽  
Vol 213 ◽  
pp. 221-225 ◽  
Author(s):  
Jeong Hwan Jang ◽  
Byeong Don Joo ◽  
Sung Min Mun ◽  
Young Hoon Moon
Keyword(s):  
Finite Element ◽  
Initial Thickness ◽  
Dimensional Changes ◽  
Rotary Swaging ◽  
Inside Diameter ◽  
Before And After ◽  
Forming Characteristics ◽  
Inner Diameter ◽  
The Given ◽  
Diameter Reduction

Studies on the forming characteristics by a rotary swaging process using the sub-scale specimens have been carried out to obtain a shell body nose of desirable quality. To analyze the changes of the nose thickness and length at the respective reduction of inside diameter, the finite element simulations were carried out. As a result, the desired target dimension is satisfied with the diameter reduction of more than 64 % for the given preform. The thickness of nose area increased up to 56.1 % from initial thickness of 2.62 mm to 4.09 mm after swaging. The values of the hardness before and after swaging were 208 HV and 325 HV, respectively. To analyze the dimensional changes (length and thickness) of nose area with decreasing inside diameter, the rotary swaging test was carried out for two different diameter reductions such as 65 % and 67 %. The lengths of nose area for the diameter reductions are 11.79 mm in 65 % and 12.53 mm in 67 %, respectively. At the diameter reduction of more than 67%, the crack occurs when the localized strain hardening reduces ductility in internal area. Therefore, the nose area should be formed from 64% to 67% reduction in target inner diameter.

Self-Organized, Tubular Hybrid Vascular Tissue Composed of Vascular Cells and Collagen for Low-Pressure-Loaded Venous System

1995 ◽  
Vol 4 (6) ◽  
pp. 597-608 ◽  
Author(s):  
Jiro Hirai ◽  
Takehisa Matsuda
Keyword(s):  
Vascular Tissue ◽  
Venous System ◽  
Seeding Density ◽  
Outer Diameter ◽  
Type I ◽  
Dependent Manner ◽  
Mixed Solution ◽  
Vascular Cells ◽  
Collagen Concentration ◽  
Inner Diameter

A tubular, hierarchically structured hybrid vascular tissue composed of vascular cells and collagen was prepared. First, a cold mixed solution of bovine aortic smooth muscle cells (SMCs) and Type I collagen was poured into a tubular glass mold composed of a mandrel and a sheath (example of dimensions: inner diameter, 1.5 mm; outer diameter, 7 mm; length, 7 cm). Upon incubation at 37°C, an SMC-incorporated collagenous gel was formed. After the sheath was removed, the resulting fragile tissue, when cultured in medium, thinned in a time-dependent manner to form an opaque, dense tissue. Higher SMC seeding density and lower initial collagen concentration induced more rapid and prominent shrinkage of the tissue. Morphologic investigation showed that over time, bipolarly elongated SMCs and collagen fiber bundles became positioned around the mandrel. Both components became circumferentially oriented. When the mandrel was removed, a tubular hybrid medial tissue was formed. A hybrid vascular tissue with a hierarchical structure was constructed by seeding endothelial cells onto the inner surface of the hybrid medial tissue. Prepared tissues tolerated luminal pressures as great as 100 mmHg and mechanical stress applied during an anastomotic procedure. This method allowed us to prepare a tubular hybrid medial tissue of predetermined size (inner diameter, wail thickness, and length) by selecting appropriate mold design, initial collagen concentration, and SMC seeding density. Such hybrid vascular tissues may provide physiological functions when implanted into the venous system.

scholarly journals Evaluation of the Lower Punctum Parameters and Morphology Using Spectral Domain Anterior Segment Optical Coherence Tomography

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Riham S. H. M. Allam ◽  
Rania A. Ahmed
Keyword(s):  
Optical Coherence Tomography ◽  
Anterior Segment ◽  
Normal Subjects ◽  
Cross Sectional Study ◽  
Spectral Domain ◽  
Outer Diameter ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Air Bubble ◽  
Inner Diameter

Purpose. To study features of the lower punctum in normal subjects using spectral domain anterior segment optical coherence tomography (SD AS-OCT).Methods. Observational cross-sectional study that included 147 punctae (76 subjects). Punctae were evaluated clinically for appearance, position, and size. AS-OCT was used to evaluate the punctal shape, contents, and junction with the vertical canaliculus. Inner and outer diameters as well as depth were measured.Results. 24 males and 52 females (mean age44±14.35 y) were included. Lower punctum was perceived by OCT to be an area with an outer diameter (mean412.16±163 μm), inner diameter (mean233.67±138.73 μm), and depth (mean251.7±126.58 μm). The OCT measured outer punctum diameter was significantly less than that measured clinically (P: 0.000). Seven major shapes were identified. The junction with the vertical canaliculus was detectable in 44%. Fluid was detected in 34%, one of which had an air bubble; however, 63% of punctae showed no contents and 4% had debris.Conclusions. AS-OCT can be a useful tool in understanding the anatomy of the punctum and distal lacrimal system as well as tear drainage physiology. Measuring the punctum size may play a role in plugs fitting.

scholarly journals STUDY OF MUTAGENIC ACTIVITY NANO- AND MICROPARTICLES IN THE AMES TEST (SALMONELLA / MICROSOME)

2019 ◽  
Vol 98 (4) ◽  
pp. 455-460
Author(s):  
Lyudmila V. Akhaltseva ◽  
V. S. Zhurkov ◽  
L. P. Sycheva ◽  
O. N. Savostikova ◽  
A. V. Alekseeva
Keyword(s):  
Carbon Nanotubes ◽  
Ames Test ◽  
Mutagenic Activity ◽  
Dose Range ◽  
Gene Mutations ◽  
Outer Diameter ◽  
Multi Walled Carbon Nanotubes ◽  
Inner Diameter ◽  
Substitution Mutations ◽  
Walled Carbon Nanotubes

Introduction. One of the important steps in assessing the nanoparticles (NP) safety is the analysis of mutagenic activity, including the evaluation of gene, chromosomal, and genomic mutations. Material and methods. The purpose of this investigation is to study the ability of different NP aqueus suspensions and the same compounds in microforms to unduce gene mutations in Salmonella/microsome test (Ames test). Anatase titanium dioxide NP coated with simethicone (33.16 ± 16.7 nm, 5-50000 μg/ml), magnetite NP coated with silicate (10 nm, 0.92-575 μg/ml), silver NP coated with аrabian gum (14 ± 0.2 nm, 5-50000 μg/ml), aluminum hydroxide nanofibres (50-70 nm, 24-3000 μg/ml) and multi-walled carbon nanotubes (Taunit MWСNTs, outer diameter 15-40 nm, inner diameter 3-8 nm, length 2 and more microns, 5-50000 μg/ml). In parallel, the mutagenic activity of equivalent microparticles was evaluated in experiments. Ames test (Salmonella/microsomes) registers gene mutations induced by a different mechanism of action, in the variant with preincubation. A set of Salmonella typhimurium indicator strains: TA 100 (base pair substitution mutations), TA 98 and TA 97 (mutations of the frameshift type of the genetic code) were used. Using addition the S9 microsomal activating mixture during the experiment makes it is possible to determine the effect not only of the substances themselves, but also of their metabolites. Conclusion. The investigated nanomaterials as well as their micro analogs in the studied dose range did not induce gene mutations in the Ames test both in presence and absence microsomal activating mixture.

Study Swaging Process for Reduction Swage Effect in Hard Disk Drive

2013 ◽  
Vol 677 ◽  
pp. 256-262 ◽  
Author(s):  
Joompondej Bamrungwongtaree ◽  
Mongkol Mongkolwongrojn
Keyword(s):  
Hard Disk Drive ◽  
Base Plate ◽  
Hard Disk ◽  
Areal Density ◽  
Disk Drive ◽  
Compression Force ◽  
Fe Method ◽  
Inner Surface ◽  
Inner Diameter

In hard disk drive manufacturing common uses ball swaging. It is a process that used to assemble a boss tower and an arm aperture. The swage ball has a larger diameter than an inner diameter of the boss tower. Application a compression force to the inner surface of the boss tower to hold both components together with adequate holding force and without damaging the boss tower components result in HGA torque retention. Measurements of HSA KPIV after swaging obtained from deformation of base plate and arm pad together. Due to hard disk drive is dynamically developed by increasing in the areal density and reducing in size, thus the arm pad is thinned. This study focuses on reducing of the swage effect by control outer arm pad deformation to maintain HSA performance. HGA torque retention was considered to reduce gap to arm and to avoid HSA resonance while swaging quality was similar. The 3-D FE method was used for analysis. The analysis and experiment show that HGA torque retention and the arm aperture modified was almost linear. Furthermore, the reduction of arm deformation and gap to arm cause increasing in HSA performance. The arm aperture can be modified for manufacturability.

C60 fullerene tubes as removable templates

2006 ◽  
Vol 21 (2) ◽  
pp. 529-534 ◽  
Author(s):  
Jun-ichi Minato ◽  
Kun'ichi Miyazawa
Keyword(s):  
Methyl Alcohol ◽  
Isopropyl Alcohol ◽  
Optical Observations ◽  
C60 Fullerene ◽  
Outer Diameter ◽  
Solution Deposition ◽  
Transmission Electron ◽  
Inner Diameter ◽  
Ultrasonic Pulverization ◽  
Capillary Attraction

Crystalline microtubes (inner diameter 240–2100 nm) consisting of C60 fullerene molecules were prepared in the mixture of C60-saturated pyridine and isopropyl alcohol kept at 0 °C. Characterization by transmission electron microscopy showed a linear relationship between the outer diameter and the inner diameter for the C60 fullerene tubes. Optical observations suggested that the specimens already had tubular structure when they were grown in the solution. Deposition of guest crystals inside the C60 fullerene tubes was performed by the following procedure: (i) ultrasonic pulverization to obtain the C60 fullerene tubes with open ends, (ii) absorption of methyl alcohol solution of KBr into the tubes by the capillary attraction, and (iii) evaporation of methyl alcohol to precipitate KBr inside the tubes. Columnar KBr crystals were then obtained by dissolving the fullerene tube walls in toluene.

Gun Liner Emplacement Using Elastomeric Materials

2010 ◽  
Author(s):  
Robert H. Carter ◽  
David M. Gray
Keyword(s):  
Refractory Metal ◽  
Outer Diameter ◽  
Elastomeric Material ◽  
Elastomeric Materials ◽  
Residual Internal Stress ◽  
Inner Diameter ◽  
Bond Strengths ◽  
Frictional Bond ◽  
Load Frame ◽  
Metal Liner

The development of a process to emplace a refractory metal liner inside a gun tube is described. The process consists of filling the liner with an elastomeric material and then slipping this arrangement into the gun tube whose inner diameter is close to the outer diameter of the liner. The ends of the liner are plugged with plastic disks and pressure is applied to the elastomeric material by a load frame. This pressure can produce a residual internal stress within the steel gun tube that produces a frictional bond between the liner and gun tube. Initial efforts have resulted in bond strengths over 3 ksi (21 MPa). In addition, by tailoring the degree of lubrication between the elastomeric material and the liner, a graded autofrettage can be produced in the steel gun tube.

209 VIABILITY OF PORCINE EMBRYOS VITRIFIED BY THE METAL MESH VITRIFICATION METHOD AFTER SURGICAL OR NONSURGICAL TRANSFER

2007 ◽  
Vol 19 (1) ◽  
pp. 221 ◽  
Author(s):  
Y. Fujino ◽  
Y. Nakamura ◽  
H. Kobayashi ◽  
S. Nakano ◽  
C. Suzuki ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Uterine Horn ◽  
Outer Diameter ◽  
Metal Mesh ◽  
Angle Bend ◽  
Fetal Bovine ◽  
Inner Diameter ◽  
Polyethylene Tubing ◽  
Practical Measure ◽  
Uterine Body

The aim of the present study was to evaluate viability of porcine embryos vitrified by the metal mesh vitrification (MMV) method after surgical or nonsurgical transfer. Prepubertal gilts were treated with eCG and hCG (= Day 0), and then inseminated artificially. Expanding blastocysts that were about 200 �m in diameter were collected on Day 7. The embryos were equilibrated in 7.5% ethylene glycol (EG) + 7.5% DMSO + 20% fetal bovine serum (FBS) in PBS at 37�C for 5 min, and then transferred into 15% EG + 15% DMSO + 0.6 M trehalose + 20% FBS in PBS for 1 min. Embryos in groups of 5 were transferred in a minimum volume of the vitrification solution (less than 1 �L) onto stainless steel mesh (75 �m screen size, 1.5 mm in width by 10 mm in length, with a 3-mm right-angle bend), and then plunged into liquid nitrogen. The mesh was stored in a 1.8-mL cryotube submerged in liquid nitrogen. Warming and dilution were performed by moving the mesh from liquid nitrogen into 0.5 M trehalose + 20% FBS in PBS at 37�C for 5 min. Embryos were rinsed twice in NCSU37 + 10% FBS (mNCSU37) for 5 min. After being vitrified, embryos in groups of 20 per recipient were suspended in modified NCSU37 medium and then transferred into gilts either by surgical transfer (5 gilts) or by nonsurgical transfer (6 sows). For surgical transfer, embryos suspended in 0.1 mL of medium were transferred into the uterine horn at 15 cm above the uterine body, which was about 35 cm from the external uterine orifice. For nonsurgical transfer, an intrauterine catheter made from polyethylene tubing (1.2 m long, 3.0 mm outer diameter, 0.5 mm inner diameter) was used. A spiral guide inserted through the vagina into the cervix was used to guide the catheter into one uterine horn. The catheter was moved through the cervix and along the uterine horn. Then, embryos suspended in 1 mL of medium were transferred. Pregnancy was assessed by ultrasonography at 30 days post-estrus. With surgical transfer, 4 of 5 recipients became pregnant, and 3 gilts farrowed a total of 21 (10, 8, 3) live piglets; the fourth gilt aborted one fetus on Day 34. With nonsurgical transfer, 3 of 6 sows became pregnant. The present study demonstrates that vitrified porcine embryos can develop after both surgical and nonsurgical transfer to recipients. As a practical measure, nonsurgical transfer of vitrified porcine blastocysts may be used instead of surgical transfer.

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