scholarly journals IV. On two new vanadium minerals

1877 ◽  
Vol 25 (171-178) ◽  
pp. 109-112 ◽  
Keyword(s):  
Specific Gravity ◽  
San Francisco ◽  
Vanadium Pentoxide ◽  
Gold Mine ◽  
Greenish Yellow ◽  
The Matrix

No. 1.—The first of these remarkable minerals contains 28 per cent. of vanadium pentoxide. It was forwarded to me by Dr. James Blake, of San Francisco, with the following statement:—“I discovered it in a gold-mine, and it serves as the matrix for the gold. It occurs in small bunches, filling cavities in a schistose porphyry." The mineral occurs in radiating and foliated talc-like masses, greenish grey in bulk, and light greenish yellow when seen in fragments, forming a grey powder. Its lustre is subvitreous to fatty. In mass it is opaque, but is translucent in thin splinters. Its hardness is about equal to that of talc; its specific gravity is 2·902.

A retrofit for asbestos-based brake pad employing palm kernel fiber as the base filler material

2018 ◽  
Vol 233 (9) ◽  
pp. 1906-1913 ◽  
Author(s):  
CH Achebe ◽  
JL Chukwuneke ◽  
FA Anene ◽  
CM Ewulonu
Keyword(s):  
Specific Gravity ◽  
Palm Kernel ◽  
Friction Material ◽  
Mechanical Tests ◽  
Filler Material ◽  
Oil Absorption ◽  
Brake Pad ◽  
Brake Pads ◽  
The Matrix ◽  
Automotive Brake

The development of automobile brake pad using locally sourced palm kernel fiber was carried out. Asbestos, a carcinogenic material, has been used for decades as a friction material. This development has thus prompted a couple of research efforts geared towards its replacement for brake pad manufacture. Palm kernel fiber was used as an alternative filler material in conjunction with various quantities of epoxy resin as the matrix. Three sets of compositions were made, and the resulting specimens subjected to physical and mechanical tests using standard materials, procedures, and equipment. The essence is to determine their suitability and hence possible performance in service. The result showed that sample C with 40% palm kernel fiber content having hardness, compressive strength, abrasion resistance, specific gravity, water absorption, and oil absorption of 178 MPa, 96.2 MPa, 1.67 mg/m, 1.8 g/cm3, 1.86%, and 0.89%, respectively, had an optimum performance rating. It was equally ascertained that increase in the filler content had the effect of increase in hardness, wear resistance, and specific gravity of the composite brake pad, while water and oil absorption got decreased when compared with results obtained by other researchers using conventional brake pads made of other friction materials including asbestos. This is an indicator that palm kernel fiber is a possible and effective retrofit for asbestos as a filler material in automotive brake pad manufacture.

scholarly journals But Will It Hold Water?

2001 ◽  
Vol 123 (03) ◽  
pp. 70-71
Keyword(s):  
Public Opinion ◽  
Real Estate ◽  
San Francisco ◽  
Work Hardening ◽  
Relative Movement ◽  
Foundation Slab ◽  
The Real Estate ◽  
Real Estate Developer ◽  
Base Steel ◽  
The Matrix

This article focuses on threat of tank failure during an earthquake that threw public opinion against the idea of development in the hills of San Francisco. If the failure mechanism could be predicted, the real-estate developer was prepared to formulate a mitigation scheme to divert the water away from the development. Sloshing of the water was idealized as a system of radial springs attached to the inside surface of the tank at the height of the convective mass. To get a second set of data for comparison, the engineers also calculated the event including the effects of work hardening. The tank’s base steel was a quarter-inch thick. Modeling the effect of friction and relative movement between the tank base and the foundation slab could have added another dimension to the matrix and boosted its credibility.

scholarly journals Determination of maturity indices of BER (Zizyphus mauritiana Lam.) Var. BARI Kul-2

2015 ◽  
Vol 40 (1) ◽  
pp. 163-176
Author(s):  
MN Islam ◽  
MM Molla ◽  
TAA Nasrin ◽  
ASM M Uddin ◽  
K Kobra
Keyword(s):  
Specific Gravity ◽  
Fruit Set ◽  
Agricultural Research ◽  
Fruit Weight ◽  
Research Centre ◽  
Yellow Colour ◽  
Greenish Yellow ◽  
Maturity Indices ◽  
Acid Ratio ◽  
Chemical Characters

A study was conducted at Fruit Research Farm and Postharvest Technology Laboratory of Horticulture Research Centre, Bangladesh Agricultural Research Institute during the period from October 2009 to February 2010 to determine the maturity indices of ber. The ber variety BARI Kul-2 was selected for conducting the study. Ber fruits were tagged at fruit setting stage and harvested at 90, 100, 110, 120 days after fruit set (treatments). The physicochemical characters like fruit weight and size, specific gravity, TSS (%), sugar (%), acidity (%), pulpstone ratio, TSS-acid ratio, sugar-acid ratio as well as subjective sensory attributes like fruit colour and texture, and storage traits like storage life, physiological weight loss (%), ripening status and decay, browning and shriveling (%) of harvested fruits were evaluated for determining the proper stage of commercial maturity. The fruit weight, TSS (%), pulp-stone ratio, TSS/acid ratio, sugar-acid ratio and specific gravity of BARI Kul-2 were found 24.33g, 15.60, 15.66, 39.72, 16.14 and 0.98, respectively, at 110 days after fruit set. Considering all the physical and chemical characters matching with subjective parameters, fruits of BARI Kul-2 was found commercially mature after 110 days of fruit set when the fruits turned into light greenish yellow to greenish yellow colour and specific gravity less than 1.00.Bangladesh J. Agril. Res. 40(1): 163-176, March 2015

Note on the Occurrence of Bismutite in the Transvaal

1887 ◽  
Vol 7 (34) ◽  
pp. 139-140
Author(s):  
Henry Louis
Keyword(s):  
Specific Gravity ◽  
Good Deal ◽  
Lemon Yellow ◽  
Brownish Yellow ◽  
Greenish Yellow ◽  
Iron Pyrites

This mineral occurs plentifully, though finely disseminated, in the veins of auriferous quartz in the Lydenburg district of the Transvaal. These veins are often capped by a "gossan" of brown hvematite, crystalline, amorphous, or at times pseudomorphous after iron pyrites; a good deal of similar brown hæmatite occurs also throughout the veins themselves. The Bismutite is disseminated irregularly through the veins, and also occurs in small pockets in the ferruginous gossan; it is from the latter source that the mineral was obtained for the subjoined description and analysis.It is amorphous, pulverulent; colour greenish yellow to lemon-yellow, more rarely brownish yellow; opaque (feebly translucent, with waxy lustre under the microscope); its hardness appears to be about 8, but cannot well be determined on account of its pulverulent character. Specific gravity 6.86.

Crystalloid Inclusions in Hepatocyte Mitochondria and Their Similarity to Cytoplasmic Crystalloids

1974 ◽  
Vol 32 ◽  
pp. 198-199
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo
Keyword(s):  
Liver Disease ◽  
Alcoholic Liver Disease ◽  
Special Interest ◽  
Structural Variations ◽  
Mitochondrial Alterations ◽  
The Matrix ◽  
Crystalloid Inclusions ◽  
Liver Biopsies

Mitochondrial alterations were studied in 25 liver biopsies from patients with alcoholic liver disease. Of special interest were the morphologic resemblance of certain fine structural variations in mitochondria and crystalloid inclusions. Four types of alterations within mitochondria were found that seemed to relate to cytoplasmic crystalloids.Type 1 alteration consisted of localized groups of cristae, usually oriented in the long direction of the organelle (Fig. 1A). In this plane they appeared serrated at the periphery with blind endings in the matrix. Other sections revealed a system of equally-spaced diagonal lines lengthwise in the mitochondrion with cristae protruding from both ends (Fig. 1B). Profiles of this inclusion were not unlike tangential cuts of a crystalloid structure frequently seen in enlarged mitochondria described below.

Coherency loss in γ' precipitates in nickel-base superalloy

1983 ◽  
Vol 41 ◽  
pp. 244-245
Author(s):  
R. A. Ricks ◽  
Angus J. Porter
Keyword(s):  
Lattice Mismatch ◽  
Lattice Parameter ◽  
Nickel Base Superalloy ◽  
Large Size ◽  
The Matrix ◽  
Nimonic 80A ◽  
Interfacial Dislocations ◽  
Nickel Base ◽  
Coherency Loss ◽  
Nimonic 115

During a recent investigation concerning the growth of γ' precipitates in nickel-base superalloys it was observed that the sign of the lattice mismatch between the coherent particles and the matrix (γ) was important in determining the ease with which matrix dislocations could be incorporated into the interface to relieve coherency strains. Thus alloys with a negative misfit (ie. the γ' lattice parameter was smaller than the matrix) could lose coherency easily and γ/γ' interfaces would exhibit regularly spaced networks of dislocations, as shown in figure 1 for the case of Nimonic 115 (misfit = -0.15%). In contrast, γ' particles in alloys with a positive misfit could grow to a large size and not show any such dislocation arrangements in the interface, thus indicating that coherency had not been lost. Figure 2 depicts a large γ' precipitate in Nimonic 80A (misfit = +0.32%) showing few interfacial dislocations.

Influence of Heat Treatments on Microstructures in an Fe-Co-V Alloy

1974 ◽  
Vol 32 ◽  
pp. 512-513
Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Supersaturated Solid Solution ◽  
Cell Formation ◽  
Heat Treatments ◽  
Air Cooling ◽  
Iced Brine ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.

Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

1977 ◽  
Vol 35 ◽  
pp. 596-597
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Synthetic Medium ◽  
Freeze Fracture ◽  
Translational Diffusion ◽  
Yeast Cells ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
The Matrix ◽  
Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

Electron microscopy and diffraction studies of polyimides

1983 ◽  
Vol 41 ◽  
pp. 28-29
Author(s):  
O.C. de Hodgins ◽  
K. R. Lawless ◽  
R. Anderson
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Structural Features ◽  
Inert Atmosphere ◽  
Polyimide Films ◽  
Resolution Electron ◽  
The Matrix ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns ◽  
Polymeric Samples

Commercial polyimide films have shown to be homogeneous on a scale of 5 to 200 nm. The observation of Skybond (SKB) 705 and PI5878 was carried out by using a Philips 400, 120 KeV STEM. The objective was to elucidate the structural features of the polymeric samples. The specimens were spun and cured at stepped temperatures in an inert atmosphere and cooled slowly for eight hours. TEM micrographs showed heterogeneities (or nodular structures) generally on a scale of 100 nm for PI5878 and approximately 40 nm for SKB 705, present in large volume fractions of both specimens. See Figures 1 and 2. It is possible that the nodulus observed may be associated with surface effects and the structure of the polymers be regarded as random amorphous arrays. Diffraction patterns of the matrix and the nodular areas showed different amorphous ring patterns in both materials. The specimens were viewed in both bright and dark fields using a high resolution electron microscope which provided magnifications of 100,000X or more on the photographic plates if desired.

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