scholarly journals A Study of the Micropore Structure of Carbonized Rayon Yarn by Nitrogen Adsorption and Nonane Pre-Adsorption

1985 ◽  
Vol 2 (2) ◽  
pp. 89-95 ◽  
Author(s):  
J. N. Bohra ◽  
K. S. W. Sing
Keyword(s):  
External Surface ◽  
Nitrogen Adsorption ◽  
The Other ◽  
Adsorption Method ◽  
Micropore Structure ◽  
Surface Areas ◽  
Three Samples ◽  
Two Samples ◽  
Before And After ◽  
Gain Access

Adsorption isotherms of nitrogen have been determined at 77 K on three samples of carbonized rayon yarn, both before and after the pre-adsorption of n-nonane. In their original state the three samples were all highly microporous. Application of the αs-method of isotherm analysis reveals that their micropore volumes were 0·17–0·19 cm3g−1 and their external surface areas 20–27 m2g−1 (the corresponding BET areas being 427–483 m2g−1). Nonane pre-adsorption resulted in blockage of the entire micropore structure only in the case of one sample: micropore volumes ∼0·1 cm3g−1 were still available for nitrogen adsorption in the other two samples. It appears that nitrogen molecules were able to gain access to some parts of these micropore structures through wider pore entrances which were not completely blocked by the pre-adsorbed nonane. The work has shown that the nonane pre-adsorption method requires further investigation before it can be used with confidence for the assessment of microporosity.

An in situ study of the phase transitions among CaCO3 high-pressure polymorphs

2018 ◽  
Vol 83 (02) ◽  
pp. 191-197 ◽  
Author(s):  
Xueyin Yuan ◽  
Chao Gao ◽  
Jing Gao
Keyword(s):  
Phase Transitions ◽  
Intermediate Phase ◽  
The Other ◽  
Three Samples ◽  
Short Period ◽  
Two Samples ◽  
Wide Pressure Range ◽  
Diamond Anvil ◽  
Wide Pressure

AbstractThe phase transitions involving calcite (CaCO3-I), CaCO3-II, CaCO3-III and CaCO3-IIIb were investigated using a diamond anvil cell and micro-Raman spectroscopy. Based on the results obtained from in situ observations and Raman measurements made with six natural calcite crystals, the phase transition from calcite to CaCO3-II took place between 1.56 and 1.67 GPa under ambient temperature. Under a precise pressure of 1.97 ± 0.03 GPa, three CaCO3 samples were observed to transform from CaCO3-II directly to CaCO3-III, while in the other three samples both CaCO3-III and CaCO3-IIIb crystal structures were detected. Transformation from CaCO3-IIIb to CaCO3-III was completed in a short period in one sample, whereas in the other two samples coexistence of CaCO3-III and CaCO3-IIIb was observed over a wide pressure range from 1.97 to 3.38 GPa, with sluggish transformation from CaCO3-IIIb to CaCO3-III being observed after the samples were preserved under 3.38 GPa for 72 h. Hence, it can be concluded that CaCO3-IIIb is a metastable intermediate phase occurring during the reconstructive transformation from CaCO3-II to CaCO3-III. Splitting of the C–O in-plane bending (ν4) and symmetric stretching (ν1) vibrations and appearance of new lattice vibrations in the Raman spectra of CaCO3-III and CaCO3-IIIb suggest a lowering in crystal symmetry during the transformation from CaCO3-II through CaCO3-IIIb to CaCO3-III, which is in good agreement with the observed sequence of phase symmetries.

The loss of activity of pyrethrum. II

1934 ◽  
Vol 24 (4) ◽  
pp. 598-626 ◽  
Author(s):  
F. Tattersfield ◽  
J. T. Martin
Keyword(s):  
The Other ◽  
Acid Method ◽  
Small Correction ◽  
Two Samples ◽  
Residual Amount ◽  
Before And After ◽  
Artificial Illumination

Summary1. The loss of activity of pyrethrum flowers and preparations has been studied.2. The degree of concordance between the content of pyrethrin I, as determined by the acid method, and the insecticidal value of pyrethrinised dusts, before and after exposure to air and artificial illumination, has been statistically examined. The pyrethrin I values, corrected for a small residual amount of extraneous matter, indicate fairly closely the degree of activity of the samples. The loss of pyrethrins on exposure has been traced out quantitatively.3. A comparison was made between two samples of pyrethrum flowers, one rich and the other poor in pyrethrins, in order to determine the degree of concordance between the pyrethrin I content and their toxicity. The pyrethrin I value as determined by the acid method, subject to a small correction, gave a good indication of the relative activities of the samples.

Surface Area of Nonporous Carbon Blacks and Area of the Adsorbed Nitrogen Molecule

1964 ◽  
Vol 37 (3) ◽  
pp. 630-634 ◽  
Author(s):  
Andries Voet
Keyword(s):  
Surface Area ◽  
Nitrogen Adsorption ◽  
Nitrogen Molecule ◽  
Adsorption Method ◽  
Chain Formation ◽  
Electron Micrography ◽  
Carbon Blacks ◽  
Surface Areas ◽  
Particle Chain ◽  
Lower Ratio

Abstract Surface areas of completely nonporous carbon blacks of widely varying particle chain formation (structure) have been determined by means of the nitrogen adsorption method as well as by electron micrography. Accurately determined densities in helium were used as the basis of calculations in the latter approach. It was found that the ratio of areas measured by nitrogen adsorption to electron micrographically determined surface areas is greatly dependent upon chain formation. A higher structural build-up leads to a lower ratio, explained by the observation that fusion areas in carbon chains are necessarily, though erroneously, counted as surfaces in electron micrography. The ratio differs markedly from unity, however, in low structure blacks, where fusion areas are negligible. By accepting the area of a nitrogen molecule adsorbed in a monolayer as being equal to that in the solid state, 13.8 A2, the ratio becomes unity for nonporous low structure blacks. It appears likely, therefore, that all surface area data based on the area of a nitrogen molecule in the liquid state of 16.2 A2 are too high by about 15 per cent of presently accepted values.

Effects of Different Molting Procedures on Incidence of Salmonella Infection in Flocks of Naturally Contaminated Laying Hens in a Commercial Egg-Producing Farm by Detection of Yolk Antibodies to Salmonella in Eggs

2006 ◽  
Vol 69 (12) ◽  
pp. 2883-2888 ◽  
Author(s):  
TOSHIYUKI MURASE ◽  
KAORI CHIBA ◽  
TOMOKO SATO ◽  
KOICHI OTSUKI ◽  
PETER S. HOLT
Keyword(s):  
Wheat Bran ◽  
Egg Production ◽  
Egg Yolk ◽  
The Other ◽  
Feed Withdrawal ◽  
Two Samples ◽  
Significant Difference ◽  
Before And After ◽  
Specific Pathogen ◽  
Egg Yolks

Indirect enzyme-linked immunosorbent assays (ELISAs) have been applied to detect immunoglobulin Y antibodies to different serotypes of Salmonella in the yolks of chicken eggs with heat-extracted antigens of Salmonella enterica serotypes Agona (SA), Cerro (SC), Enteritidis (SE), Montevideo (SM), and Putten (SP). The egg yolk samples examined were classified as positive if their ELISA absorbance values exceeded the value for eggs from specific-pathogen-free flocks by more than two standard deviations. Of 30 egg yolk samples from three flocks vaccinated with a killed SE vaccine, 29 were antibody positive by the ELISA assay for the SE antigen. Four to 29 of the 29 yolk samples showed positive results for the other serovars, although the absorbance values for SE were higher than those obtained for the other serotypes in each of the yolk samples. All 30 yolks from three flocks that were not administered any SE vaccines were found to be antibody negative for SE, and two samples were determined to be positive for SC. Thirty-nine or 40 eggs were obtained from each of four layer flocks in a commercial egg production farm where the laying houses were naturally contaminated with SA, SC, SM, SP, Salmonella serovar Infantis (SI), and untypeable strains. The ELISA absorbance values for SM in the egg yolks obtained from the two flocks molted through feed withdrawal when the birds restarted laying were significantly (P < 0.05) higher than those observed in the yolks obtained before the molt. In egg yolks from the two other flocks that were molted through a wheat bran diet, there was no significant difference between the absorbance values before and after the molt. The observations in the present study provide further evidence to suggest that a molt initiated through the administration of a wheat bran diet can reduce the risk for Salmonella problems in a commercial egg-producing setting.

SWELLING BEHAVIOUR OF MIXED-LAYER CLAYS IN HYDROCARBON RESERVOIRS

1994 ◽  
Vol 34 (1) ◽  
pp. 366
Author(s):  
Julian C. Baker ◽  
Philippa J.R. Uwins ◽  
Ian D.R. Mackinnon
Keyword(s):  
Morphological Change ◽  
Mixed Layer ◽  
Hydrocarbon Reservoirs ◽  
Environmental Scanning ◽  
Three Samples ◽  
Two Samples ◽  
Before And After ◽  
Porosity And Permeability ◽  
Freshwater Sensitivity

The freshwater sensitivity of a variety of mixed-layer illite/smectite and chlorite/smectite clays has been studied with an Environmental Scanning Electron Microscope (ESEM) in order to determine whether all hydrocarbon reservoirs hosting these clays should be regarded as freshwater sensitive. Experimental procedures involved closely comparing in situ mixed-layer clay within selected areas at high magnification before and after prolonged freshwater treatments.The response of smectite-rich illite/smectite (two samples; 10–20 per cent illite interlayers) to freshwater immersion varied greatly. One sample rapidly swelled to many times its original volume to form a pervasive gel that greatly reduced porosity and permeability, whereas the other sample underwent only a subtle morphological change that had little or no adverse effect on reservoir quality. Illite-rich illite/smectite (three samples; 65—>85 per cent illite interlayers) and chlorite-rich chlorite/smectite (two samples; 50 per cent and >70 per cent chlorite interlayers) underwent no morphological change when immersed in freshwater for up to three months, indicating that these clays in sandstones are unlikely to cause formation damage due to swelling if exposed to freshwater-based fluids.

The Impact of Adopting Electronic Trading System on Performance of the Amman Stock Exchange

2013 ◽  
Vol 03 (03) ◽  
pp. 29-36
Author(s):  
Najeb M.H. Masoud
Keyword(s):  
Stock Exchange ◽  
Market Value ◽  
The Other ◽  
Electronic Trading ◽  
Trading System ◽  
Two Samples ◽  
Significant Difference ◽  
Amman Stock Exchange ◽  
Before And After ◽  
The Impact

This study aims to highlight the impact of adopting electronic trading System on performance of the Amman Stock Exchange (ASE) represented in the (value traded) and (market capitalisation) where, for the implementation of that, secondary data were collected from (taken from the monthly statistical bulletins of the Stock Exchange) related to the study variables, where an analysis of the difference between the middle two samples: the first study variables before the introduction of the system, and the other after you have inserted, to find out whether there is a significant difference between the size of the stock exchange in trading before and after the introduction of the electronic trading system, and whether there is a significant difference between the value between the market value of securities listed on the stock exchange before and after the introduction of the system. The results of the study show that the use of the electronic trading system as an alternative to the manual trading system has contributed to raise the volume of trading and the market value of the ASE. We believes that the result of the increase in the degree of transparency and security for traders and investors in the stock market, and give great flexibility and different information to brokers facilitated an analysis of the situation of companies traded faster, which achieved more justice, speed and ease of execution of orders, on the other hand, the system has led to facilitate control over the trading operations and the dissemination of information in real time for both local or foreign investors which contributes to increase the depth and liquidity of the market.

Diversity of entomopathogenic nematodes (Nematoda: Steinernematidae, Heterorhabditidae) from Arasbaran forests and rangelands in north-west Iran

Nematology ◽  
2010 ◽  
Vol 12 (5) ◽  
pp. 767-773 ◽  
Author(s):  
Mostafa Nikdel ◽  
Gholamreza Niknam ◽  
Christine T. Griffin ◽  
Naser Eivazian Kary
Keyword(s):  
Entomopathogenic Nematodes ◽  
Common Species ◽  
Soil Samples ◽  
The Other ◽  
Undescribed Species ◽  
North West ◽  
Three Samples ◽  
Two Samples ◽  
Molecular Studies ◽  
Species Being

Abstract A survey for entomopathogenic nematodes (EPN) was carried out in the Arasbaran forests and rangelands, East Azarbaijan province, north-west Iran, during 2006 to 2008. A total of 691 soil samples were collected from 62 localities across the region of which 21 samples (3%) were positive for EPN, including nine samples (1.3%) with heterorhabditids and 12 (1.7%) with steinernematids. Seven isolates (four Steinernema and three Heterorhabditis) were recovered from rangelands and 14 (eight Steinernema and six Heterorhabditis) from forest soil samples. Based on morphology and molecular studies, the Heterorhabditis isolates were identified as H. bacteriophora and the Steinernema isolates as S. carpocapsae, S. bicornutum, S. feltiae, S. glaseri, S. kraussei and three undescribed species referred to here as Steinernema sp. IRAZ7, Steinernema sp. IRAZ13 and Steinernema sp. IRAZ21. Heterorhabditis bacteriophora, the most common species, was present in nine soil samples collected across the forests and rangelands, and of the Steinernema species, S. bicornutum was obtained from three samples, the other species being found from only one or two samples.

Elimination of Chromium (VI) by Adsorption onto Natural and/or Modified Kaolinite

2018 ◽  
Vol 18 ◽  
pp. 106-112 ◽  
Author(s):  
Nouel Hezil ◽  
Mamoun Fellah ◽  
Omar Assala ◽  
Mohamed Zine Touhami ◽  
Kamel Guerfi
Keyword(s):  
Specific Surface ◽  
Cationic Surfactant ◽  
Interlayer Space ◽  
Nitrogen Adsorption ◽  
Surface Areas ◽  
Chromium Vi ◽  
Two Samples ◽  
Modification Method ◽  
Aqueous Effluents ◽  
Chromate Ion

The purpose of this study is to compare the effectiveness of a natural and / or modified kaolinite to adsorb chromium-containing aqueous effluents in its most toxic form (the hexavalent chromate ion (Cr (VI)). Adsorbant used in the present study is a kaolinite of hydrothermal origin. The modified kaolinite has been prepared by insertion of a cationic surfactant DTAC in interlayer space of this clay. The modification method is generally performed by the cation exchange reaction in the liquid state. The specific surface areas determined by nitrogen adsorption at 77 K for the two samples of kaolinite (natural and modified) are succinctly 48.75 and 63.72 m2/g. Scanning electron microscopy has shown that the used clay is in tubular form. The treatment of natural kaolin by the intercalation of cationic surfactant increased its specific surface of about 18 %. Therefore its power sorptif increased which was found by a comparative study of adsorption of Cr (VI) on natural kaolin and / or modified.

Nitrogen adsorption on synthetic akaganeite and its structural implications

Clay Minerals ◽  
1977 ◽  
Vol 12 (4) ◽  
pp. 345-352 ◽  
Author(s):  
E. Paterson ◽  
J. M. Tait
Keyword(s):  
Specific Surface ◽  
Electron Micrographs ◽  
Nitrogen Adsorption ◽  
Structural Scheme ◽  
Qualitative And Quantitative ◽  
Surface Areas ◽  
Two Samples ◽  
Specific Surface Areas ◽  
Adsorptive Properties ◽  
Quantitative Assessments

AbstractComparison of the adsorptive properties of two samples of akaganéite prepared by different methods shows that a structural scheme based upon solid rods is much more likely than a previously proposed scheme involving tubes. Specific surface areas, qualitative and quantitative assessments of porosity' and electron micrographs strongly support this structure.

Use of Sodium Substitutes in Cottage Cheese and Buttermilk

1986 ◽  
Vol 49 (2) ◽  
pp. 117-120 ◽  
Author(s):  
B. J. DEMOTT ◽  
J. P. HITCHCOCK ◽  
P. M. DAVIDSON
Keyword(s):  
Sodium Concentration ◽  
The Other ◽  
Cottage Cheese ◽  
Psychrotrophic Bacteria ◽  
Three Samples ◽  
Two Samples ◽  
Salt Substitute ◽  
Standard Plate ◽  
Plate Counts ◽  
Yeasts And Molds

Twenty-four market samples of cottage cheese had an average sodium concentration of 4.91 ± 1.20 mg/g. Two samples of cottage cheese formulated to contain 1.1% “Lite” and Zyest, and having sodium concentrations of 3.23 and 2.54 mg/g had significantly lower flavor scores than a sample containing 1.4% NaCl and having 6.25 mg of Na/g. The Standard Plate Counts and the yeast and mold counts on the cottage cheese after storing 10 d at 4°C were not different between samples containing salt, salt substitute or salt substitute plus a dry yeast preparation. Psychrotrophic bacteria were more numerous in the samples containing the yeast preparation. Four samples of buttermilk containing .015% “Zyest 45-F” and .25% NaCl, .25% “Lite” and .015% “Zyest 45-F”, .25% NaCl, or .25% “Lite” had comparable flavor scores. The sodium concentrations of the four samples were 1.096, .793, 1.125 and .771 mg/g, respectively. The growth of yeasts and molds in samples containing “Zyest 45-F” and “Lite” was slightly but not significantly greater than the other three samples. Psychrotrophic counts on buttermilk after 7 d of storage at 4°C were much lower than the original counts, but were not influenced by the additives used.

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