Calcium Nitrate Solution Research Articles

Effect of preharvest foliar sprays of calcium nitrate on melon fruit quality

The aim of this work was to study the effect of preharvest foliar spraying with calcium nitrate solutions on the fruit melon quality. Treatments included a combination of five solutions with Ca(NO3)2 (0.0; 1.3; 2.6; 5.2 and 1... | Find, read and cite all the research you need on Tech Science Press

Growth and variability of wheat seedlings in calcium nitrate solutions

Growth and variability of wheat seedlings in calcium nitrate solutions

添加剂对氧化钇陶瓷显微结构的影响

本论文通过在氧化钇试样表面滴加添加剂溶液使添加剂浓度在试样内呈梯度变化，然后将试样于1600℃下烧结以研究添加剂种类及添加剂的浓度对氧化钇晶粒生长的影响。结果发现滴加有硝酸钙的氧化钇试样中存在晶粒异长长大现象，氧化钇晶粒粗大。滴加有硝酸铈的氧化钇试样中氧化钇晶粒均匀，细小，气孔较少。因此，采用滴加的方式可以节约实验成本，提高实验效率。 To investigate the effect of the kind and concentration of additives on the grain growth of Y2O3, different kinds of additives solutions were dropped on the surface of Y2O3 samples and immersed in gradient, and then the samples were sintered at 1600˚C in present work. The results showed that in the sample added with calcium nitrate solution, abnormal grain growth was obtained and the Y2O3 grains were remarkably coarsened. In the sample with cerium nitrate solution, uniform and fine Y2O3 grains were observed and pores were seldom in the matrix. Hence, the application of dropping method can save the experimental cost and improve the efficiency of the experiment.

Response two cultivars of gladiolus to different treatments of putrescine, nutrition and media under soilless condition

This experiment was conducted to study the effects of Hoagland solution, putrescine (50 and 100 ppm), calcium nitrate solution, and coco peat: perlite medium with three ratios (v/v) (1: 1, 3: 1 and 1: 3) on some vegetative parameters and biochemical parameters of two cultivars of gladiolus (strong and white) under soilless condition in 2016. Data indicated that most criteria of vegetative parameters expressed as corm sprouting (day), number of corm and number of cormels and biochemical parameters expressed as soluble sugar (mg/g F.W), phenols (mg/100g F.W) and ascorbic acid (mg/100g F.W) significantly increased corm sprouting, number of corm and number of cormels, soluble sugar, phenols and ascorbic acid by the white cultivar (7.09 days), (1.56), (32.33), (4.87 mg/g), (28.56 mg/100g) and (8.36 mg/100g) respectively, while significantly increased by the coco peat: perlite medium with ratio (1: 3) (7.90 day), (1.59), (33.33), (4.58 mg/g), (28.91 mg/100g) and (8.13 mg/100g) respectively. In contrast, the all parameters were study that showed significantly increased by the application of Hoagland solution + putrescine 100 ppm (7.46 day), (2.18), (45.00), (6.23 mg/g), (37.01 mg/100g) and (11.71 mg/100g) respectively. As the results showed, there was a significant interaction between cultivars and media, media and treatments, cultivars and treatments and cultivars, media and treatment only in corm sprouting. While the results also showed that there was no significant interaction in other parameters was study.

A microstructural study of the degradation and calcium release from hydroxyapatite-calcium oxide ceramics made by infiltration

Hydroxyapatite pellets, partially densified in a low-temperature heat treatment, were infiltrated with calcium nitrate solution followed by in-situ precipitation of Ca(OH)2 and CaCO3. The infiltrated bodies were then densified to high relative density and the calcium carbonate transformed to calcium oxide during sintering and resulted in biphasic hydroxyapatite-CaO ceramics. This work investigated the influence of the infiltration on surface morphology, weight change, and microstructural-level degradation caused by exposure to saline at pH=7.4 and a temperature of 20°C. The CaO rendered the materials more susceptible to degradation, and released calcium into the saline faster than single phase, calcium deficient hydroxyapatite (HA) that were used as a control. In consequence, these ceramics could be used to release calcium into the culture microenvironments of bone tissue or bone marrow cells next to a scaffold surface.

Electrochemical Deposition of Materials for Biomedical Applications

Electrochemical methods have been developed for the deposition of biopolymer films containing hydroxyapatite, and other bioceramics, such as titania, silica and bioglass. Different electrochemical methods have been utilized for the deposition of natural biopolymers, such as chitosan, polyacrylic acid and hyaluronate. Chitosan was protonated and dissolved in acidic solutions and then deposited cathodically. In this approach the charge neutralization of cationic chitosan in the high pH region at the electrode surface resulted in the precipitation of insoluble chitosan. Electrodeposition of alginic acid was performed from sodium alginate solutions. In this method the pH decrease at the anode surface resulted in the charge neutralization of alginate macromolecules and the fabrication of alginic acid films on anodic substrates. A similar approach has been utilized for the deposition of hyaluronic acid from the sodium hyaluronate solutions. It was demonstrated that cathodic and anodic deposition methods can be used for the deposition of other biopolymers. Nanoparticles of hydroxyapatite were prepared by a chemical precipitation method. Precipitation was performed at 70 °C by the slow addition of a 0.6 M ammonium phosphate solution into a 1.0 M calcium nitrate solution. The pH of the solutions was adjusted to 11 by NH4OH. Stirring was performed during 8 h at 70 °C and then 24 h at room temperature. The precipitate was washed with water and finally with ethanol. The average length of the needle-shape HA crystals, prepared by this method, was about 150 nm and the average aspect ratio was 8. The composite films containing HA nanoparticles in chitosan, alginic acid and hyaluronic acid matrix were prepared on stainless steel, Ti and NiTi alloy substrates. The results of thermogravimetric analysis showed that hydroxyapatite content in the polymer matrix was varied in the range of 35-80 wt% by variation of hydroxyapatite or polymer concentration in the solutions. The deposition yield was studied at different deposition conditions. It was shown that film thickness can be varied in the range of 0.1-200 microns by variation of the deposition time in the range of 1-10 min and deposition voltage in the range of 10-60 V. The composite films were prepared as monolayers or multilayers containing hydroxyapatite-polymer layers, separated by the layers of pure polymer. The co-deposition of inorganic materials with biopolymers resulted in the fabrication of novel composite materials containing bioactive glass and other bioactive materials, such as silica and titania in a polymer matrix. Electrochemical techniques have been also applied for the fabrication of materials of graded composition (FGM) containing biopolymers, hydroxyapaite and other bioceramics and bioglass. Electrochemical impedance spectroscopy and potentiodynamic polarization studies showed that the composite coatings provided corrosion protection of the metallic substrates in simulated body fluid solutions. The use of biopolymers enabled the room temperature processing of the coatings, eliminating the problems related to the sintering of hydroxyapatite and other bioceramics. Moreover, the method enabled the incorporation of drugs and proteins in the composite material. Electrochemical strategies have been developed for the deposition of composite films containing heparin and albumin in a biopolymer matrix. The room temperature processing offers a possibility of co-deposition of other functional materials and fabrication of advanced nanocomposite coatings for biomedical applications. New deposition methods were developed for cathodic deposition of chiral biopolymers, such as poly-l-lysine and polyl-ornithine. As an extension of these investigations, the composite films, containing HA nanoparticles and other functional biomaterials in the matrix of chiral biopolymers were obtained and investigated. Further development of new deposition methods resulted in the development of electrophoretic strategies and deposition mechanisms for the deposition of linear polyethylenimine, polypyrrole, polyetheretherketone, polyacrylic acid. Fundamental mechanisms were developed for the co-deposition of enzymes and proteins with various biopolymers. We discovered a possibility of electrophoretic co-deposition of halloysite nanotubes with cationic and anionic biopolymers, such as chitosan, poly-l-lysine and polyl-ornithine, alginic acid, hyaluronic acid, polyacrylic acid. The halloysite nanotubes can be loaded with drugs and antimicrobial agents for the controlled release. The new composite materials are prtomising for applications in biomedical implants and biosensors. We investigated functional properties of new materials, fundamental deposition mechanisms and kinetics of deposition.

Technological and kinetic regularities of formation of suspension and its interaction with nitric acid while obtaining calcium nitrate

The results of studying the processes of forming calcium hydroxide transportation suspensions and their neutralization by nitrate acid with the development of energy­saving technologies of obtaining calcium nitrate were presented. As a result of the research, the process of calcium oxide hydration in the calcium nitrate solution was substantiated and the mechanism of the suspension thickening was proposed. The limit lime concentrations in the calcium nitrate solutions were established, the process of calcium oxide hydration in these solutions was theoretically calculated. The mechanism of thickening of the prepared suspension (suspension of Са(ОН) 2 in Са(NO 3 ) 2 solution), based on the formation of hydrogen bonds due to the presence of oxygen with unfilled orbitals, was explored. The degree of CaO conversion (kinetics of hydration) depending on the time and the intensity of mixing in 35 % solution of calcium nitrate, which increases from 0.67 to 0.89 o. n. with an increase in the intensity of mixing Re=1000 ÷ 13000 was established. The limit of the lime content for different concentrations of Са(NO 3 ) 2 ) was defined: for 15 %­solution of calcium nitrate, the highest possible lime concentration on conversion to СаО is 350 g/dm 3 , for 20 %­solution, it is 320 g/dm 3 , for 25 %­solution, it is 295 g/dm 3 , for 30 %­solution, it is 275 g/dm3, for 35 %­solution – 240 g/dm 3 and for 40 %­solution, it is 200 g/dm 3 , respectively. The results of the experimental research presented in the form of graphical dependencies and tabular data may be used for the improvement of existing and design of the new production facilities of calcium nitrate.

Research of calcium oxide hydration in calcium nitrate solutions

Research of calcium oxide hydration in calcium nitrate solutions

Processing, structure and magnetic properties correlation in co-precipitated Ca-ferrite

La-substituted hexagonal calcium ferrite, Ca1−XLaXFe12O19 (x varies from 0 to 0.6 with the step of 0.2), was synthesized by applying co-precipitation method, in which the molar ratio of Fe3+/(Ca2++La2+) was 11. The ferrite precursors were prepared from aqueous solution of calcium nitrate, ferric nitrate and lanthanum nitrate by co-precipitation of calcium, iron and lanthanum ions by using an aqueous base of sodium hydroxide (1.5M) at the pH of 14 and at room temperature. These precursors were calcinated with different amount of La at different temperature of 700, 1100 and 1200°C for constant calcination time of 1h in a static air atmosphere. Some tests such as simultaneous thermal analysis (STA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were carried out to investigate the thermal behavior, crystallographic properties, morphology and magnetic properties of the precursor powders which were calcinated at different temperatures. The powder XRD patterns of samples which consisted of La as dopant and were calcinated at 1200°C for 1h, indicates the formation of calcium hexaferrite and also α-Fe2O3 besides Magnetoplumbite-phase (M-phase). However, the results showed that CaFe4O7 and α-Fe2O3 phases were formed in the sample with the same condition but without using any dopant. The results of SEM showed that the calcium hexaferrite particle were regular hexagonal platelets with the size range of 1–2µm. The magnetic properties such as maximum magnetization (MMax), remanent magnetization (Mr) and coercivity (Hc) were measured from the hysteresis loops. Low values of coercive field (16.3kAm−1) and maximum magnetization (50.6Am2kg−1) were obtained from calcium hexaferrite particle in optimum amount of La (X=0.4) which calcinated at the temperature of 1200°C.

Combustion assisted synthesis of hardystonite nanopowder

In this study, single-phase hardystonite (Ca2ZnSi2O6) nanopowder was synthesized by combustion synthesis method from aqueous solution of Calcium nitrate, Zinc nitrate and Tetraethyl orthosilicate. In order to characterize the obtained powders, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used. The effect of sucrose concentration on the purity and morphology of the obtained hardystonite powder, and its initial annealing temperature was investigated. The optimum sucrose to metal ratio was found to be 2:1. The average particle size and the maximum crystallite size of the produced hardystonite nanopowder were 220 and 40nm, respectively.

Calcium Phosphate Ceramic Based on Powder Synthesized From a Mixed-Anionic Solution

Ceramic based on calcium phosphates is obtained from powders synthesized from water solutions of calcium nitrate, ammonium hydrophosphate, and ammonium pyrophosphate as well as from a mixed-anionic solution containing simultaneously ammonium pyro- and orthophosphate in the molar ratio (NH4)2HPO4/(NH4)4P2O7 = 1. The ceramic obtained contains biocompatible bioresorbable phases and can be used to make implants used in regenerative methods for the treatment of bone tissue defects. This represents the first time synthesis from mixed-anionic solutions is used to obtain powders of calcium phosphates with significant quantities of each anion.

Calcium phosphate with high specific surface area synthesized by a reverse micro-emulsion method

ABSTRACTA reverse micro-emulsion method has been investigated to control crystal morphology in a nanometer region and to increase specific surface area for calcium phosphate. The nanocrystals with the control of its morphology is a candidate of drug delivery carriers. This study investigated the effects of mixing volume ratios of two surfactants, tween80 (T) and aliquate 336 (A) in kerosene as an oil phase, and pH values in the nano-region on crystalline phases and specific surface area of calcium phosphate synthesized by the reverse micro-emulsion method. A di-ammonium hydrogen phosphate solution including phosphoric acid at pH of 6.3 and a calcium nitrate solution at pH of 5.7 were adjusted, and both the solutions were separately added into the kerosene with the surfactants. Both the emulsions were then mixed at the same volume and the Ca/P ratio of 1.0, and stirred at room temperature for 24 hours. The crystalline phases were dependent on the T amounts; pure DCPD with the specific surface area of 6.7 to 12 m2/g was obtained at the T/A ratio of 4, the mixture of DCPD and DCPA with that of 48 to 162 m2/g was at the ratios of 5 to 8, and a low crystalline HAp with 163 m2/g was at the ratio of 9. These specific surface areas of DCPD (T/A=4) and HAp (T/A=9) were apparently higher than those prepared with a wet method, 7.8 times and 1.8 times respectively. DCPA with 43 m2/g was successfully produced to decrease the pH of phosphate solution at T/A of 9. The change of crystalline phases would be explained as follows; the increase of T amount decreased the micro-emulsion sizes to reduce bulk water to be DCPA, and increased the pH to precipitate HAp nanocrystals.

Conversion of Calcium Nitrate Solution Obtained from Kyzylkum Phosphorite with Ammonium Carbonate

Conversion of Calcium Nitrate Solution Obtained from Kyzylkum Phosphorite with Ammonium Carbonate

Generation of bio-compatible titanium alloy surfaces by laser-induced wet treatment

A laser-induced surface treatment in wet conditions was developed for improving the biocompatibility of titanium alloys. Disk-shaped titanium samples were soaked in a calcium nitrate solution and subsequently irradiated by a Yb fiber pulse laser beam, creating a modified surface layer containing calcium and oxygen elements. The modified layer exhibited optimal properties for treatment at a defocus distance of −1mm and for a calcium nitrate concentration of 10%. The apatite-forming ability of the modified surface was affirmed in bioactivity tests performed in the simulated body fluid. It was shown that a Ca-rich layer was stably generated by the modified treatment process. The generated Ca-rich layer demonstrated superior biocompatibility, suggesting increased hydroxyapatite content.

Use of Reverse Osmosis Reject Water for Value Addition in Coco Substrate Industry

Previous studies corroborated that water enriched with various compounds is a major reason for Chronic Kidney Disease of Unknown Aetiology (CKDu) in Sri Lanka. Reverse osmosis (RO) units are being introduced in the CKDu prevalent areas for water purification. Generally, the RO reject water is disposed of directly to the ground and/or used for irrigation purposes because it contains several minerals, which are favourable for the growth of plants. However, this practice may cause any negative environmental issues. Calcium nitrate is used as a value addition in coco substrate industry to wash out sodium from the coir products because sodium competes with other cations which are essential for plant growth in the process of adsorption. However, discharging the spent calcium nitrate solution to land for irrigation purposes may lead to nitrate pollution. This study investigates the possibility of using RO reject water, which has considerably high amounts of calcium, as an alternative for the use of calcium nitrate, which may also lead to reduction of cost of importing calcium nitrate. Leachability tests were carried out using husk chips as the solid medium with RO reject water and calcium nitrate as the treatment solution, respectively. When RO reject water was used as the washing solution, the results manifested (amount of calcium, magnesium adsorbed and sodium, potassium leached out) that the leachability potential was well within the acceptable range as per the protocols. Based on the findings, RO reject water could be proposed as an alternative source to calcium nitrate. Keywords: Calcium nitrate, Coco substrate, Husk chips, Reverse osmosis, Water purification

EFFECT OF SEVERAL CALCINATION TEMPERATURE ON DIFFERENT CONCENTRATION ZINC SUBSTITUTED CALCIUM PHOSPHATE CERAMICS

Zinc substituted calcium phosphate ceramics powders were produced from precipitation method using calcium nitrate, zinc nitrate and ammonium dihydrogen phosphate solutions. Several zinc ions concentrations (5, 10, and 15 mole %) were substituted into calcium phosphate ceramics with the (Ca+Zn)/P initial ratio were set to 1.67. Calcium phosphate powders were then calcined at 600, 700, 800, 900, and 1000°C to observe its effect on the material phase behavior. By increasing the calcination temperature, XRD peaks changed from broad to narrower shape indicating that the powders are highly crystalline. Hydroxyapatite (HA) partly transformed to another phase which is tricalcium phosphate (β-TCP) at 700°C confirming the formation of biphasic calcium phosphate ceramics. FESEM observations clearly exhibit that the particles are in nanosized scale which explains why as zinc concentration increases, the particles tend to be agglomerated.

Development of gelatin-chitosan-hydroxyapatite based bioactive bone scaffold with controlled pore size and mechanical strength

Hydroxyapatite–chitosan/gelatin (HA:Chi:Gel) nanocomposite scaffold has potential to serve as a template matrix to regenerate extra cellular matrix of human bone. Scaffolds with varying composition of hydroxyapatite, chitosan, and gelatin were prepared using lyophilization technique where glutaraldehyde (GTA) acted as a cross-linking agent for biopolymers. First, phase pure hydroxyapatite–chitosan nanocrystals were in situ synthesized by coprecipitation method using a solution of 2% acetic acid dissolved chitosan and aqueous solution of calcium nitrate tetrahydrate [Ca(NO3)2,4H2O] and diammonium hydrogen phosphate [(NH4)2H PO4]. Keeping solid loading constant at 30 wt% and changing the composition of the original slurry of gelatin, HA–chitosan allowed control of the pore size, its distribution, and mechanical properties of the scaffolds. Microstructural investigation by scanning electron microscopy revealed the formation of a well interconnected porous scaffold with a pore size in the range of 35–150 μm. The HA granules were uniformly dispersed in the gelatin–chitosan network. An optimal composition in terms of pore size and mechanical properties was obtained from the scaffold with an HA:Chi:Gel ratio of 21:49:30. The composite scaffold having 70% porosity with pore size distribution of 35–150 μm exhibited a compressive strength of 3.3–3.5 MPa, which is within the range of that exhibited by cancellous bone. The bioactivity of the scaffold was evaluated after conducting mesenchymal stem cell (MSC) – materials interaction and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay using MSCs. The scaffold found to be conducive to MSC’s adhesion as evident from lamellipodia, filopodia extensions from cell cytoskeleton, proliferation, and differentiation up to 14 days of cell culture.

The Influence of Chloride and Nitrite Solution Exposure on Mechanical Properties of Industrially Produced Plaster Mixtures

Lime and cement-lime industrially produced dry plaster mixtures are widely used building materials. These surface treatments can come into the contact with salt solutions which cause their degradation. On this account, the influence of calcium nitrate and calcium chloride water solution exposure on mechanical properties of several commercially produced mortars is researched in the paper. The prismatic specimens having dimensions of 40/40/160 mm are cured 28 days in humid environment. Then, the studied specimens are stored 112 days in both salt solutions and reference environment of distilled water. At specific time intervals, the compressive and bending strengths are measured and the obtained data are discussed.

Synthesis and characterization of Ag-containing calcium phosphates with various Ca/P ratios.

Ag-containing calcium phosphate (CaP) powders were synthesized by a precipitation method using aqueous solutions of calcium nitrate, silver nitrate, and ammonium phosphate. The powders were sintered at temperatures ranging from 1173 to 1473 K. The charged atomic ratios of (Ca+Ag)/P and Ag/(Ca+Ag) in solution were varied from 1.33 to 1.67 and from 0 to 0.30, respectively. The Ag content in the as-precipitated CaP powders increased with the charged Ag/(Ca+Ag) atomic ratio in solution and was lower than the charged Ag/(Ca+Ag) value. The as-precipitated CaP powders consisted of hydroxyapatite (HA) as the main phase. Ag nanoparticles were observed on the as-precipitated HA particles under all conditions of Ag addition. After the sintering, HA, β-TCP (tricalcium phosphate), α-TCP, and β-CPP (calcium pyrophosphate) were mainly detected as CaPs on the basis of the Ca/P atomic ratio of the as-precipitated powders. The addition of Ag stabilized the β-TCP phase, and the distribution of Ag in β-TCP was homogeneous. A metallic Ag phase coexisted with HA. The solubility of Ag in HA was estimated to be 0.0019-0.0061 (Ag/(Ca+Ag)) atomic ratio, which was lower than that in β-TCP (higher than 0.0536) and higher than that of β-CPP (below the detection limit of analyses).

Structural characterizations of three-dimensional crimped silk yarns

Silk yarns which are composed of two single yarns with different twist directions are treated with calcium nitrate solution at 95 ?C, and a 3-D crimped structure is formed. The Fourier transform infrared spectroscopy spectrum is used to reveal the change of the secondary structures of silk fiber.