Mirsid volcanic tuff, alkaline activation, dissolved species, optimum activation time, optimum activating concentration

2020 ◽  
Vol 71 (2) ◽  
pp. 196-201
Author(s):  
Erika Reisz ◽  
Corneliu-Mircea Davidescu ◽  
Radu Ardelean ◽  
Liviu Costea
Keyword(s):  
Sudden Increase ◽  
Activation Time ◽  
Volcanic Tuff ◽  
X Ray ◽  
Second Stage ◽  
Dissolved Species ◽  
Species Optimum ◽  
Potassium Magnesium ◽  
Exchange Properties ◽  
Activating Solution

The purpose of this article is to study the activation of the Mir�id volcanic tuff with NaOH solutions at various concentrations. To be more specific, the work investigated the evolution of the concentrations of species that passed from the tuff into the activating solutions and the quantities of dissolved species from 100 g tuff. The species found in the activating solution were: potassium, magnesium, aluminium and silicon. The shape of the curves - a sudden increase followed by a plateau or a second stage of slower increase - allowed for setting up the optimal activation time at a half-hour. Another finding was the optimal concentration of 1 N for the activating solution. X-ray diffractograms showed the increase of clinoptilolite content in the tuff, thus improving the adsorbent as well as ion exchange properties by activation with NaOH solutions.

The effect of dehydration and rehydration on salt loss in the second-stage larvae of Anguina tritici

Parasitology ◽  
1981 ◽  
Vol 82 (3) ◽  
pp. 411-419 ◽  
Author(s):  
C. Womersley
Keyword(s):  
Salt Content ◽  
Atomic Absorption Spectrophotometry ◽  
Sodium Content ◽  
Sodium Potassium ◽  
X Ray ◽  
Second Stage ◽  
Absorption Spectrophotometry ◽  
Nematode Cuticle ◽  
Calcium Loss ◽  
Potassium Magnesium

SUMMARYThe effect of repeated dehydration and hydration on the salt content of 2nd-stage larvae of Anguina tritici was studied. The sodium, potassium, magnesium and calcium contents of the larvae after subjection to varying periods of desiccation and rehydration were determined with atomic absorption spectrophotometry and flame photometry. External cation concentrations on the cuticle of the head, middle body and tail regions were determined semi-quantitatively with scanning electron microscopy in conjunction with X-ray analysis (EDAX). Salt concentrations decreased with each dehydration/rehydration cycle. The greatest loss occurred on revival from the first desiccation period. The results indicated that A. tritici was incapable of regulating it's internal sodium content during revival, but suggested a limited ability to control potassium, magnesium and calcium loss. Salt loss through the nematode cuticle was restricted to potassium and calcium during desiccation. The salt losses encountered are discussed in relation to nematode osmoregulation and to the survival of the nematode in the anhydrobiotic state.

scholarly journals Search for intermittent X-ray pulsations from neutron stars in low-mass X-ray binaries

2021 ◽  
Vol 38 ◽  
Author(s):  
Yunus Emre Bahar ◽  
Manoneeta Chakraborty ◽  
Ersin Göğüş
Keyword(s):  
Neutron Stars ◽  
Orbital Period ◽  
Oscillation Frequency ◽  
Orbital Motion ◽  
X Rays ◽  
X Ray ◽  
Second Stage ◽  
Corrected Data ◽  
Low Mass ◽  
X Ray Binaries

Abstract We present the results of our extensive binary orbital motion corrected pulsation search for 13 low-mass X-ray binaries. These selected sources exhibit burst oscillations in X-rays with frequencies ranging from 45 to 1 122 Hz and have a binary orbital period varying from 2.1 to 18.9 h. We first determined episodes that contain weak pulsations around the burst oscillation frequency by searching all archival Rossi X-ray Timing Explorer data of these sources. Then, we applied Doppler corrections to these pulsation episodes to discard the smearing effect of the binary orbital motion and searched for recovered pulsations at the second stage. Here we report 75 pulsation episodes that contain weak but coherent pulsations around the burst oscillation frequency. Furthermore, we report eight new episodes that show relatively strong pulsations in the binary orbital motion corrected data.

Elemental composition of globoids in the perisperm tissue of various seeds

1995 ◽  
Vol 73 (6) ◽  
pp. 954-957 ◽  
Author(s):  
M. Marcia West ◽  
Derrick T. Flannigan ◽  
John N.A. Lott
Keyword(s):  
Energy Dispersive ◽  
Mineral Nutrient ◽  
Piper Nigrum ◽  
X Ray ◽  
Phytate Phosphorus ◽  
Transmission Electron ◽  
Yucca Brevifolia ◽  
Nutrient Reserves ◽  
Mature Seeds ◽  
Potassium Magnesium

The mature seeds of some angiosperms contain perisperm tissue derived from remains of the nucellus tissue of the ovule. In our transmission electron microscopy studies, the perisperm tissues of the seeds of Yucca brevifolia, Coffea arabica, Beta vulgaris, Piper nigrum, and Zostera capricorni contained naturally electron-dense globoids. Energy dispersive X-ray analysis of globoids from the perisperm tissues of these seeds revealed varying levels of phosphorus, potassium, magnesium, and calcium, results that are consistent with the presence of the mineral nutrient store called phytate. Phosphorus, potassium, magnesium, calcium, and other mineral nutrients, likely stored as phytate, have routinely been located in globoids of endosperm, female gametophyte, and embryo tissues of seeds. Key words: perisperm, globoids, mineral nutrient reserves, phosphorus, seeds, energy dispersive X-ray analysis.

scholarly journals Alkali Activation of Oil Shale Ash Based Ceramics

2012 ◽  
Vol 9 (3) ◽  
pp. 1373-1388 ◽  
Author(s):  
A. Hamadi ◽  
K. Nabih
Keyword(s):  
Oil Shale ◽  
Experimental Approach ◽  
Acid Leaching ◽  
Alkali Activation ◽  
X Ray Diffraction ◽  
Oil Shale Ash ◽  
X Ray ◽  
Eds Analysis ◽  
Shale Ash ◽  
Activating Solution

Timahdit oil shale was subjected to firing transformation via ceramics processing followed by alkali activation to synthesis a materials combining the mechanical properties of ceramics and Zeolites. The mineralogical transformations during firing oil shale have been studied. The main crystalline phases found in oil shale ash (OSA) were wollastonite, gehlenite and augite. Modified oil shale ash (MOSA) was obtained with HNO3acid-leaching in the aim to diminish Ca content. Our experimental approach required a NaOH alkaline activating solution with different concentrations (0.5; 1; 2; 4; 6 and 8M). In our study, X-ray diffraction (XDR), Fourier transform infrared (FTIR) and SEM/EDS analysis were used to evaluate the effect of alkali activation on the structural arrangement of the starting materials (OSA and MOSA) in our study. The quantity and the type of the produced zeolites depended critically on the starting materials and on the NaOH concentration.

Influence of Alloying Additions on Enhancement of Soft Magnetic Properties Effect and Crystallization in FeXSiB (X=Cu, V, Co, Zr, Nb) Amorphous Alloys

2007 ◽  
Vol 130 ◽  
pp. 171-174 ◽  
Author(s):  
Z. Stokłosa ◽  
G. Badura ◽  
P. Kwapuliński ◽  
Józef Rasek ◽  
G. Haneczok ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Crystallization Process ◽  
Annealing Temperature ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
X Ray ◽  
Second Stage ◽  
Transmission Electron

The crystallization and optimization of magnetic properties effects in FeXSiB (X=Cu, V, Co, Zr, Nb) amorphous alloys were studied by applying X-ray diffraction methods, high resolution transmission electron microscopy (HRTEM), resistometric and magnetic measurements. The temperatures of the first and the second stage of crystallization, the 1h optimization annealing temperature and the Curie temperature were determined for different amorphous alloys. Activation energies of crystallization process were obtained by applying the Kissinger method. The influence of alloy additions on optimization effect and crystallization processes was carefully examined.

scholarly journals Mechanical Activation of Smectite-Based Nanocomposites for Creation of Smart Fertilizers

2022 ◽  
Vol 12 (2) ◽  
pp. 809
Author(s):  
Maxim Rudmin ◽  
Santanu Banerjee ◽  
Boris Makarov ◽  
Kanipa Ibraeva ◽  
Alexander Konstantinov
Keyword(s):  
Electron Microscopy ◽  
Interlayer Space ◽  
Soil Leaching ◽  
X Ray Diffraction ◽  
Activation Time ◽  
Release Rates ◽  
X Ray ◽  
Weight Losses ◽  
Transmission Electron ◽  
Scanning Electron

This research presents the mechanical creation of smart fertilizers from a mixture of smectite and urea in a 3:2 ratio by using the planetary milling technique. The smectite–urea composites show intercalation between urea and mineral, which increases steadily with increasing activation time. A shift of X-Ray Diffraction basal reflections, intensities of Fourier transform infrared spectroscopy (FTIR) peaks, and weight losses in thermogravimetric analysis (TG) document the systematic crystallo-chemical changes of the composites related to nitrogen interaction with activation. Observations of the nanocomposites by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) corroborate the inference. Nitrogen intercalates with smectite in the interlayer space and remains absorbed either within micro-aggregates or on the surface of activated smectites. Soil leaching tests reveal a slower rate of nitrogen than that of traditional urea fertilizers. Different forms of nitrogen within the composites cause their differential release rates to the soil. The formulated nanocomposite fertilizer enhances the quality and quantity of oat yield.

scholarly journals Genipap flour and its technological potential for food production and manufacturing

2021 ◽  
Vol 10 (16) ◽  
pp. e404101622533
Author(s):  
Daniel Rocha Cardoso ◽  
Fernanda Pereira da Silva Rocha ◽  
Robson Alves da Silva ◽  
Marcelo Melo Viana ◽  
Ayse Suzel Martins Cosme ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Infrared Spectra ◽  
Food Production ◽  
Freeze Drying ◽  
Primary Alcohols ◽  
X Ray Diffraction ◽  
X Ray ◽  
Technological Characteristics ◽  
Technological Potential ◽  
Potassium Magnesium

This research aimed to evaluate the technological potential of genipap flour (Genipa americana L.) in freeze drying and oven drying processes. The ripened genipap fruits were harvested and submitted to pulp extraction, which after dehydration in an oven and freeze drying, were crushed to obtain the flours. When analyzed by X-ray diffraction, the flours were amorphous, with indicative of starch. In addition, the presence of water, aromatics and primary alcohols was observed by infrared spectra (FTIR). In micrograph (SEM) FPJDE was less porous and starches were identified. For thermogravimetry (TGA) similar thermal events occurred, it was important to verify the thermal behavior, humidity and ash present in the food. In the mineral composition, potassium, magnesium, manganese, iron, phosphorus, copper, and calcium were present, the flours as a source of manganese and with a high content of iron, potassium, copper and magnesium. It was concluded that the flours present a quantity of nutrients and favorable technological characteristics such as: thermal stability, humidity below that established by law for the manufacture and production of food.

Influence of Aging Time on the Structural Changes of Cassava Thermoplastic Starch

2012 ◽  
Vol 1372 ◽  
Author(s):  
José H. Mina ◽  
Alex Valadez ◽  
Pedro J. Herrera-Franco ◽  
Tanit Toledano
Keyword(s):  
Yield Stress ◽  
Amorphous Phase ◽  
Structural Changes ◽  
Thermoplastic Starch ◽  
X Ray Diffraction ◽  
X Ray ◽  
Second Stage ◽  
Diffraction Patterns ◽  
Type V ◽  
Stress Drops

ABSTRACTIn this work the change in the structural properties of cassava (manihot sculenta Crantz) thermoplastic starch (TPS) under controlled environment (humidity and temperature) was studied. Fourier Transform Infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results showed an evident increasing in the amorphous phase of the TPS regarding the native starch. There was a relative decrease of the band at 1047 cm-1 associated to crystalline structure of starch compared to the amorphous peak at 1022 cm-1. The X-ray diffraction patterns confirmed the increment of the amorphous phase in the TPS samples. Likewise the X-ray diffraction patterns shows evidence of residual type C crystallinity and the formation of a new crystalline phase type VH due to the orientation induced in plasticization process. In first stage of conditioning the tensile yield stress drops from 7.5 drops to 0.5 MPa and the break strain increases 1000%. At the same time it seems that the crystallinity of the samples increases as was evidenced by the gradually increasing of the FTIR band at 1047 cm-1. In a second stage, the yield stress increases, the break strain drops and the crystallinity continue growing steadily. These findings suggest that coexist two phenomena simultaneously in the samples. A phenomenon of re-crystallization (retrogradation) that tends to make the material more stiff and a process of plasticization that tends to softening it. It seems that the latter mechanism predominates in the first stage, at short times, and the former in the second stage, at older times.

Beobachtungen von Stapelfehlordnungen bei der Oxydation der zweiten zur ersten Stufe des Graphithydrogensulfats / Observation of stacking disorder during the oxidation of second stage to first stage graphite hydrogensulfate

1984 ◽  
Vol 39 (8) ◽  
pp. 768-777 ◽  
Author(s):  
Ko Young Shin ◽  
Hanns-Peter Boehm
Keyword(s):  
Interlayer Spacing ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Second Stage ◽  
Intermediate Phases ◽  
Degree Of Oxidation ◽  
Stage 1 ◽  
Kinetics Of ◽  
Stacking Disorder

Graphite has been oxidized to graphite hydrogensulfate with (NH4)2S2Og in concentrated H2SO4. The stage 2 compound formed very rapidly, but further oxidation to stage 1 could be followed conveniently. X-ray diffraction of the intermediate phases showed nonintegral (00l)-reflections indicative of partial interstratification disorder. The interlayer spacing of the stage 1 compound increased with continued oxidation. The degree of oxidation as function of oxidation time has been determined from the position of the minima in the reflectance spectra. The density of the compounds and the ratio of acid molecules to anions in the intercalated layers has been estimated using these data and those of buoyancy measurements. There is a minimum in packing density early in the formation of the first stage. The kinetics of intercalation seems to be first order with respect to the free interlayer spaces.

scholarly journals Preparation and Properties of Nanocellulose from Miscanthus x giganteus

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Valerii A. Barbash ◽  
Olha V. Yashchenko ◽  
Olesia A. Vasylieva
Keyword(s):  
Structural Changes ◽  
Thermochemical Treatment ◽  
Crystallinity Index ◽  
Alkaline Treatment ◽  
X Ray Diffraction ◽  
Miscanthus X Giganteus ◽  
X Ray ◽  
Second Stage ◽  
20 Nm ◽  
Hydrolysis Of

Miscanthus x giganteus stalks were used to make organosolvent pulp and nanocellulose. The organosolvent miscanthus pulp (OMP) was obtained through thermal treatment in the mixture of glacial acetic acid and hydrogen peroxide at the first stage and the alkaline treatment at the second stage. Hydrolysis of the never-dried OМP was carried out by a solution of sulfuric acid with concentrations of 43% and 50% and followed by ultrasound treatment. Structural changes and the crystallinity index of OMP and nanocellulose were studied by SEM and FTIR methods. X-ray diffraction analysis confirmed an increase in the crystallinity of OMP and nanocellulose as a result of thermochemical treatment. We show that nanocellulose has a density of up to 1.6 g/cm3, transparency up to 82%, and a crystallinity index of 76.5%. The AFM method showed that the particles of nanocellulose have a diameter in the range from 10 to 20 nm. A thermogravimetric analysis confirmed that nanocellulose films have a denser structure and lower mass loss in the temperature range of 320–440°C compared to OMP. The obtained nanocellulose films have high tensile strength up to 195 MPa. The nanocellulose obtained from OMP exhibits the improved properties for the preparation of new nanocomposite materials.

Sign in / Sign up

Export Citation Format

Share Document