CLAY-INORGANIC STUDIES. II. HYDROXY ALUMINUM PHOSPHATE–MONTMORILLONITE COMPLEX

1975 ◽  
Vol 55 (2) ◽  
pp. 225-233 ◽  
Author(s):  
H. KODAMA ◽  
M. D. WEBBER
Keyword(s):  
Relative Humidity ◽  
Room Temperature ◽  
Aluminum Phosphate ◽  
Silicate Layer ◽  
Basal Spacing ◽  
Minor Amount ◽  
Chemical Compositions ◽  
A Minor ◽  
Positively Charged ◽  
Water Contents

Two specimens of hydroxy aluminum phosphate interlayer materials in montmorillonite clay were prepared with 7.20 meq Al and 11.29 meq H3PO4/g clay and with 14.40 meq Al and 22.58 meq H3PO4/g clay, and the resulting complexes studied by chemical and mineralogical methods. Both interlayer materials were slightly positively charged and except for different water contents their chemical compositions were almost identical. They contained Al, PO4 and H2O and a minor amount of Ca and approximated hydrous AlPO4∙nH2O. The mole ratios of Al:Ca:PO4:OH were 1.00:0.08:0.92:0.24 and 1.00:0.05:0.91:0.24, respectively. The interlayer materials appeared to be loosely packed and distributed sparsely in interspaces of the montmorillonite. The degree of packing was greater for the preparation with the larger amount of interlayer material. The materials increased the montmorillonite basal spacing to 23.3 Å under air-dry condition (30–40% relative humidity) but did not affect the lateral dimensions. The basal spacing varied somewhat with relative humidity at room temperature and decreased markedly as water was driven off by heating. Heat treatments between room temperature and 300 C sharply reduced the d001 spacings to 16.7 Å which persisted up to 700 C. It is postulated that the large basal spacings occur because the hydrated interlayer materials have a framework structure with tunnels along the c-axis. This being so, changes in the spacings with different humidities might result from the movement of water molecules among interstitial spaces existing around and between the loosely distributed molecules of interlayer material. The 16.7 Å spacing for the dehydrated phase corresponds to the sum of 7.0 Å, the edge dimension of an orthorhombic anhydrous AlPO4 and 9.7 Å, the silicate layer thickness.

scholarly journals Influence of Sodium Dodecyl Sulfonate on the Formation of ZnO Nanorods fromε-Zn(OH)2

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jing Wang ◽  
Chengxiang Liu ◽  
Lan Xiang
Keyword(s):  
Aspect Ratio ◽  
Molecular Simulation ◽  
Room Temperature ◽  
Zno Nanorods ◽  
Sodium Dodecyl ◽  
Experimental Results ◽  
Minor Amount ◽  
Sodium Dodecyl Sulfonate ◽  
Naoh Solution ◽  
A Minor

The influence of sodium dodecyl sulfonate (SDSN) on the formation of ZnO nanorods fromε-Zn(OH)2was investigated in this paper. Theε-Zn(OH)2precursor was prepared at room temperature using ZnSO4and NaOH as the reactants and then converted to ZnO nanorods after aging at 80°C in NaOH solution containing a minor amount of sodium dodecyl sulfonate (SDSN). The experimental results and the molecular simulation revealed that the influence of SDSN on the formation of ZnO fromε-Zn(OH)2should be attributed to the adsorption of SDSN onε-Zn(OH)2surfaces, which inhibited the dissolution ofε-Zn(OH)2in NaOH solution, leading to the formation of the ZnO nanorods with a diameter of 50–200 nm, a length of 3.0–15.0 μm, and an aspect ratio of 30–100.

Strengthening and Ductilization of D03-Type Fe3Al Intermetallic Alloys by Dispersion of Laves Phases Fe2Zr and Fe2Nb

2007 ◽  
Vol 561-565 ◽  
pp. 395-398 ◽  
Author(s):  
N. Matsumoto ◽  
Yasuyuki Kaneno ◽  
Takayuki Takasugi
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Room Temperature ◽  
Tensile Elongation ◽  
Minor Amount ◽  
Second Phase ◽  
Intermetallic Alloys ◽  
High Tensile Strength ◽  
Laves Phases ◽  
A Minor

Zr and/or Nb added Fe3Al based intermetallic alloys (i.e., Fe3Al-Zr, Fe3Al-Nb and Fe3Al-Zr-Nb) were arc-melted, homogenized, hot-rolled and then annealed to evaluate microstructure and tensile property at room temperature as well as at a high temperature (873K). After annealing, the rolled alloys exhibited a recrystallized microstructure containing coarse second phase particles, except for the Nb-added alloy with a minor content of Nb. Relatively high tensile elongation as well as high tensile strength was observed at room temperature in the Zr-added alloys with a minor amount of Zr. Also, these alloys showed relatively high tensile strength and elongation at high temperature (873K). The results suggest that tensile ductility as well as strength of Fe3Al-based alloys can be improved by introduction of the second phase dispersions.

scholarly journals Characterizing the solid hydrolysis product, UF4(H2O)2.5, generated from neat water reactions with UF4 at room temperature

2021 ◽  
Vol 50 (7) ◽  
pp. 2462-2471
Author(s):  
Jonathan H. Christian ◽  
Christopher A. Klug ◽  
Michael DeVore ◽  
Eliel Villa-Aleman ◽  
Bryan J. Foley ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hydrolysis Product ◽  
Minor Amount ◽  
Neat Water ◽  
A Minor

Anhydrous UF4 stirred in water for 1–6 days forms UF4(H2O)2.5 and a minor amount of uranyl fluoride. This hydrolysis results in morphological and spectroscopic changes.

The 5.6-Kilodalton Protein in Isolated Chlorosomes of Chloroflexus aurantiacus Strain Ok -70-fl is a Degradation Product

1990 ◽  
Vol 45 (7-8) ◽  
pp. 823-828 ◽  
Author(s):  
Kai Griebenow ◽  
Alfred R. Holzwarth ◽  
Kurt Schaffner
Keyword(s):  
Protease Inhibitors ◽  
Proteolytic Activity ◽  
Degradation Product ◽  
Room Temperature ◽  
Chloroflexus Aurantiacus ◽  
Minor Amount ◽  
Phenylmethylsulfonyl Fluoride ◽  
A Minor

Abstract Chlorosomcs containing BChl a790 have been isolated from Chloroflexus aurantiacus on sucrose density gradients using the detergents Miranol. Deriphat. N.N-dimethyldodecyl- aminc-N-oxidc, and dodecyl-p-D-rnaltoside. All freshly prepared samples cither lack the poly- peptide of approximately 5 kDa. which appears identical with the 5.6-kDa protein previously assigned the role of BChl c-binding [R. G. Feick and R. C. Fuller. Biochemistry 23, 3693- 3700 (1984)]. or they contain only a minor amount thereof. This polypeptide accumulates in the chlorosomcs in vitro at room temperature within 24 h after isolation. The reaction cannot be prevented simply by addition of the protease inhibitors benzamidinc. F.-caproic ac|d. and phenylmethylsulfonyl fluoride. However, upon denaturation, as required lor gel electrophore- sis, of the freshly isolated chlorosome sample the formation of the 5-kDa polypeptide is inhibit- ed. We conclude that this species, viz. 5.6-kDa protein, is a degradation product of another - as yet unidentified - protein present in the chlorosome preparations. Despite the pronounced proteolytic activity which affords the 5-kDa fragment, the native absorption and fluorescence properties of BChl c and BChl a arc essentially not changed in these chlorosome preparations.

scholarly journals Odour-active compounds in liquid malt extracts for the baking industry

2021 ◽  
Author(s):  
Nadine S. Rögner ◽  
Veronika Mall ◽  
Martin Steinhaus
Keyword(s):  
Threshold Value ◽  
Starting Material ◽  
Minor Amount ◽  
Malt Extract ◽  
Important Process ◽  
Gas Chromatography Olfactometry ◽  
Odour Threshold ◽  
A Minor ◽  
Baking Industry ◽  
Insight Into

AbstractAn odorant screening by gas chromatography–olfactometry (GC–O) and a crude aroma extract dilution analysis (AEDA) applied to the volatiles isolated from a light and a dark liquid malt extract (LME) by solvent extraction and solvent-assisted flavour evaporation (SAFE) identified 28 odorants. Fifteen major odorants were subsequently quantitated and odour activity values (OAVs) were calculated as ratio of the concentration to the respective odour threshold value (OTV). Important odorants in the light LME included 3-(methylsulfanyl)propanal (OAV 1500), (E)-β-damascenone (OAV 430), and 4-ethenyl-2-methoxyphenol (OAV 91). In the dark LME, sotolon (OAV 780), 3-(methylsulfanyl)propanal (OAV 550), (E)-β-damascenone (OAV 410), acetic acid (OAV 160), and maltol (OAV 120) were of particular importance. To get an insight into the changes during malt extract production, the quantitations were extended to the malt used as the starting material for both LMEs. Addition of a minor amount of water to malt before volatile extraction was shown to be effective to cover the free as well as the bound malt odorants. Results showed that some LME odorants originated from the starting material whereas others were formed during processing. Important process-induced LME odorants included (E)-β-damascenone and 4-ethenyl-2-methoxyphenol in the light LME as well as maltol, sotolon, (E)-β-damascenone, and 2-methoxyphenol in the dark LME. In summary, the odorant formation during LME production was shown to be more important than the transfer of odorants from the malt.

scholarly journals Back protection of canvas paintings

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Tim Padfield ◽  
Nicolas Padfield ◽  
Daniel Sang-Hoon Lee ◽  
Anne Thøgersen ◽  
Astrid Valbjørn Nielsen ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Relative Humidity ◽  
Temperature Variation ◽  
Room Temperature ◽  
Single Point ◽  
Confined Space ◽  
Constant Wall Temperature ◽  
Back Plate ◽  
Inner Surface

Abstract In this paper different scenarios for back protection of a canvas painting and their effect on the stability of the relative humidity behind the painting are tested. A painting on canvas, stretched on a wooden frame, was fitted with various styles of back protection and then exposed to a cycle of temperature variation at the back, with the front exposed to a constant room temperature. The painting was also exposed to a constant wall temperature and varying room temperature. The space between the canvas and the back board was fitted with temperature and relative humidity (RH) sensors. The sensors were used to provide the essential single-point data of temperature and RH at the given locations. For more comprehensive understanding of the rather confined space, further numerical simulation (computational fluid dynamics) was adopted as part of the investigation. The computational fluid dynamics was used to understand the natural convection within the microclimate through the depictions of temperature distribution, as well as the corresponding airflow. The unprotected painting suffered a large RH variation at its back, because of the varying canvas temperature interacting with the constant room air moisture content. Effective stabilisation of the RH behind the canvas against temperature variation was provided by a shiny aluminium alloy sheet sealed against the frame. The non-absorbent back board experienced a strong variation in RH, because of humidity buffering of the space by the painting canvas at a different temperature. Either a space or insulation between this back plate and the wall reduced the risk of condensation on the inner surface of the back plate. Insulation will however increase the risk of condensation on the wall surface behind the painting. An absorbent back board de-stabilised the RH at the painting canvas surface by providing a competing humidity buffer at a different temperature. To provide protection against moisture exchange with an unsuitable room RH, extra humidity buffer was placed 3 mm behind the painting canvas, kept close to the painting temperature by insulation between this buffer and the back board. This stabilised RH at the canvas surface but increased both the temperature and the RH variation at the back board and thus increased the risk of condensation on the inner surface of the back board. The RH and the temperature in the narrow spaces between the painting canvas and the wooden stretcher frame were always more nearly constant than in the open canvas area, which suggests an explanation for the widely observed better condition of the areas of canvas paintings which lie close over the support structure. Our conclusion is that a non-absorbent, impermeable back plate gives good RH stability against a changing temperature gradient between wall and canvas painting surface.

Preparation and Characterization of Modified PVDF-g-PSSA Membrane

2010 ◽  
Vol 152-153 ◽  
pp. 44-50 ◽  
Author(s):  
Gui Bao Guo ◽  
Er Ding Han ◽  
Sheng Li An
Keyword(s):  
Relative Humidity ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Proton Exchange Membrane ◽  
Vinylidene Fluoride ◽  
Proton Exchange ◽  
Poly Vinylidene Fluoride ◽  
Relative Humidity Range ◽  
Exchange Membrane

A new method based on a solution graft technique was used to prepare poly (vinylidene fluoride) grafted polystyrene sulfonated acid (PVDF-g-PSSA) proton exchange membrane. Polystyrene is grafted into PVDF modified by plain sodium silicate (Na4SiO4). There is a linear relationship between the degree of grafting and the content of Na4SiO4. Fourier transform infrared spectroscopy is used to characterize changes of the membrane's microstructures after grafting and sulfonation. The morphology of the membrane's microstructures after grafting and sulfonation is studied by scanning electrolytic microscope (SEM). The effect of plain sodium silicate (Na4SiO4) concentration and relative humidity on the conductivity of the electrolyte was investigated by the impedance at room temperature. The results show that the styrene has been grafted into PVDF. The conductivity of PVDF-g-PSSA electrolyte doped 10% plain sodium silicate (Na4SiO4) is 0.016 S/cm at room temperature. The conductivity of the electrolyte changes slightly at a relative humidity range of 20%-70%. The weightlessness of PVDF-g-PSSA electrolyte heated to 40°C was less than 2%, which indicated that water capacity was good.

Utilization of open pit burned household waste ash – a feasibility study in Dhaka

2014 ◽  
Vol 32 (5) ◽  
pp. 397-405
Author(s):  
Md. Obaidul Haque ◽  
Ahmed Sharif
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
Bottom Ash ◽  
Open Pit ◽  
Household Waste ◽  
Chemical Compositions ◽  
Muffle Furnace ◽  
Clay Bricks ◽  
Peripheral Area

Informal incineration or open pit burning of waste materials is a common practice in the peripheral area of Dhaka, one of the fastest growing mega-cities in the world. This study deals with the effect of open pit burned (i.e. open burned) household waste bottom ash on fired clay bricks. Between 0 to 50% (by weight) of open pit burned household waste bottom ash was mixed with clay to make bricks. The molded specimens were air-dried at room temperature for 24 h and then oven dried at 100 °C for another 24 h to remove the water. The raw bricks were fired in a muffle furnace to a designated temperature (800, 900 and 1000 °C, respectively). The firing behaviour (mechanical strength, water absorption and shrinkage) was determined. The microstructures, phase compositions and leachates were evaluated for bricks manufactured at different firing temperatures. These results demonstrate that open pit burned ash can be recycled in clay bricks. This study also presents physical observations of the incinerated ash particles and determination of the chemical compositions of the raw materials by wet analysis. Open pit burned ash can be introduced easily into bricks up to 20% wt. The concentrations of hazardous components in the leachates were below the standard threshold for inert waste category landfill and their environmental risk during their use-life step can be considered negligible.

scholarly journals Vinyl ether hydrolysis. XIV. 2-Methoxy-2,3-dihydropyran: concurrent reaction of vinyl ether and acetal functional groups

1980 ◽  
Vol 58 (21) ◽  
pp. 2199-2202 ◽  
Author(s):  
R. A. Burt ◽  
Y. Chiang ◽  
A. J. Kresge
Keyword(s):  
Vinyl Ether ◽  
Isotope Effect ◽  
Reaction Rate ◽  
Functional Group ◽  
Minor Amount ◽  
Cyanoacetic Acid ◽  
Buffer Solutions ◽  
Hydrogen Isotope Effect ◽  
A Minor ◽  
Hydrolysis Of

The hydrolysis of 2-methoxy-2,3-dihydropyran shows a normal isotope effect (kH/kD > 1) under catalysis by the hydrogen ion and gives an accurately linear dependence of reaction rate upon undissociated acid concentration in cyanoacetic acid and formic acid buffer solutions. This substrate, therefore, unlike its higher homolog, 9-methoxyoxacyclonon-2-ene, provides no evidence in support of an anything but a normal mechanism for vinyl ether hydrolysis. Analysis of the hydrogen isotope effect suggests that a minor amount (8%) of this hydrolysis occurs via reaction of the acetal functional group.

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