Decrease In Supersaturation Research Articles

Accelerated convergence via adiabatic sampling for adsorption and desorption processes.

Under isothermal conditions, phase transitions occur through a nucleation event when conditions are sufficiently close to coexistence. The formation of a nucleus of the new phase requires the system to overcome a free energy barrier of formation, whose height rapidly rises as supersaturation decreases. This phenomenon occurs both in the bulk and under confinement and leads to a very slow kinetics for the transition, ultimately resulting in hysteresis, where the system can remain in a metastable state for a long time. This has broad implications, for instance, when using simulations to predict phase diagrams or screen porous materials for gas storage applications. Here, we leverage simulations in an adiabatic statistical ensemble, known as adiabatic grand-isochoric ensemble (μ, V, L) ensemble, to reach equilibrium states with a greater efficiency than its isothermal counterpart, i.e., simulations in the grand-canonical ensemble. For the bulk, we show that at low supersaturation, isothermal simulations converge slowly, while adiabatic simulations exhibit a fast convergence over a wide range of supersaturation. We then focus on adsorption and desorption processes in nanoporous materials, assess the reliability of (μ, V, L) simulations on the adsorption of argon in IRMOF-1, and demonstrate the efficiency of adiabatic simulations to predict efficiently the equilibrium loading during the adsorption and desorption of argon in MCM-41, a system that exhibits significant hysteresis. We provide quantitative measures of the increased rate of convergence when using adiabatic simulations. Adiabatic simulations explore a wide temperature range, leading to a more efficient exploration of the configuration space.

Effect of a high-citrate beverage on urine chemistry in patients with calcium kidney stones.

A well-accepted strategy to prevent kidney stones is to increase urine volume by increasing oral intake of fluids, especially water, to lower supersaturation of the relevant, relatively insoluble salts, and thereby lower the risk of precipitation. Randomized controlled trials have shown that this strategy works. It is inexpensive, safe, and intuitively attractive to patients. However, although any beverage can increase urine volume, and citrus juices can increase urine citrate content and pH, no beverage other than water has been clearly shown by randomized controlled trial to prevent kidney stones. We designed an innovative, palatable, low-calorie, high alkali citrate beverage to prevent kidney stones, called Moonstone. One packet of Moonstone powder, mixed in 500ml of water, contains 24.5meq of alkali citrate. We administered one packet twice a day to ten calcium stone formers. Moonstone resulted in an increase in mean 24-h urine citrate and urine pH, and a decrease in supersaturation of calcium oxalate in calcium stone formers compared to an equal volume of water. These changes, comparable to those seen in a prior study of a similar amount of (potassium-magnesium) citrate, will likely be associated with a clinically meaningful reduction in kidney stone burden in patients with calcium stones. The effect to increase urine pH would also be expected to benefit patients with uric acid and cystine stones, groups that we hope to study in a subsequent study. The study preparation was well tolerated and was selected as a preferred preventative strategy by about half the participants. Moonstone is an alternative, over-the-counter therapy for kidney stone prevention.

Effect of Non-Specific Ion Adsorption and Parallel Faradaic Reactions on the Nucleation of H2 Nanobubbles

We report voltammetric experiments of single H2 nanobubble nucleation at Pt nanodisk electrodes (radius < 100 nm) in the presence of highly-charged species: Ru(NH3)6 3+, La3+, Fe(CN)6 3−, and Fe(CN)6 4−. The highly charged cations are expected to be non-specifically adsorb at electrode potentials sufficiently negative for the H2 evolution reaction (HER) to proceed, thus affecting the thermodynamics and kinetics of bubble formation through alterations in interfacial solution structure. Conversely, anions are not expected to be non-specifically adsorbed during H2 evolution. We observed a more highly complex behavior than expected: (i) the presence of the two redox ions that are simultaneously reduced at potentials where HER occurs (i.e., Ru(NH3)6 3+ and Fe(CN)6 3−) results in a large overpotential for HER and bubble nucleation as well as a decrease in the H2 supersaturation required for nucleation; (ii) the presence of the electroinactive cation, La3+, results in a decrease in H2 supersaturation but no increase in HER overpotential; and (iii) Fe(CN)6 4− has only a minor effect on both HER kinetics and H2 supersaturation. We infer that the driving force of nucleation decreases in the presence of highly-charged ions. The results also suggest that the HER rate is significantly decreased when parallel redox reactions are operative.

Microphysical Piggybacking in the Weather Research and Forecasting Model

AbstractThis paper presents incorporation of the microphysical piggybacking into the Weather Research and Forecasting (WRF) model. Microphysical piggybacking is to run a single simulation applying two microphysical schemes, the first scheme driving the simulation and the second piggybacking this simulated flow. “Driving the simulation” means that the simulated microphysical processes, affect the cloud buoyancy and thus force the simulated flow. In contrast, the piggybacking variables are advected by the simulated flow and undergo microphysical transformation, but they do not affect the simulated flow (like in prescribed flow—kinematic—simulations). The two sets of variables (driver and piggybacker) include temperature, water vapor mixing ratio, and all microphysical variables. We provide details of implementing piggybacking into the WRF model, illustrate its applications, and demonstrate the benefits of this methodology in two idealized three‐dimensional cases: (a) a squall line case applying two microphysics schemes, the Thompson bulk microphysics scheme and the University of Pécs/NCAR bin (UPNB) scheme. The piggybacking simulations revealed that the microphysics‐dynamics interaction plays a more important role than the pure microphysical size sorting effect in the transition zone formation. (b) A case of daytime shallow‐to‐deep convective development over land. This case uses the UPNB scheme and contrasts convection developing in environments with either pristine or polluted cloud condensation nuclei (CCN). The piggybacking results indicated that the increase of cloud cover and decrease of supersaturation are mainly associated with the microphysical effect of increasing CCN while the change of precipitation on the ground is also influenced by microphysics‐dynamics interactions.

Investigating the effects of process parameters on the filtration performance of ferric hydroxide in a continuous MSMPR reactor

Iron removal in the nickel industry is achieved by precipitation and filtration, and for enhanced process efficiency, the filtration step must be improved. A mixed-suspension-mixed-product-removal (MSMPR) reactor set-up operating at steady-state was established, simulating industrial conditions, and the effect of temperature and residence time on filtration performance of the precipitated akaganéite was investigated. Increasing the reaction temperature and residence time improved the filtration performance, where temperature had the most prominent effect, reducing the specific filter cake resistance with over one order of magnitude from 25 °C to 75 °C. However, there must be a trade-off between temperature increase and cost-effectiveness. A lower moisture content in the filter cakes was also observed with increasing residence time and temperature, which is advantageous in terms of handling of waste and for potential reuse of the iron precipitates. Elevated temperatures resulted in formation of particles with higher crystallinity, lower surface area and higher stability towards aggregation. These particle characteristics were explained by the significant decrease in supersaturation at steady-state at higher temperatures. Variation in residence times, on the other hand, did not affect the solution supersaturation but was still an important parameter on the particle characteristics, which in turn had implications on the filtration performance. The significant changes observed in specific filter cake resistance and filter cake moisture content, but not in supersaturation, with varying residence times were explained by internal rearrangements and locally induced ageing of the particles.

Study on optical performance and 532 nm laser damage of rapidly grown KDP crystals

Type II samples were obtained from the adjacent positions of pyramidal sector and prismatic sector in the same potassium dihydrogen phosphate (KDP) single crystal grown by the “point seed” technique under different temperature range and supersaturation. Some samples were annealed at 160 °C for 24 h. The UV–Vis spectra, especially in the ultraviolet region, show the optimal transmitting ability for the KDP crystal which was grown under relative low temperature range. The structural analysis performed by means of Fourier transformed infrared spectroscopy (FTIR) suggests that the crystal lattice of the KDP grown under relative small supersaturation become compact at the molecular level. The results of photoluminescence (PL) emission spectra show that the PL intensity increases with the rise of supersaturation and growth temperature range, which indicates that the concentration of all the detected micro defects in the KDP is abundant. The damage threshold conducted using 532 nm ns laser pulses shows the same trend with the results of PL spectra. The laser-induced damage threshold (LIDT) has been improved with the decrease of growth temperature range and supersaturation, and its variation has the highest correlation with the concentration of hydrogen vacancy defect. In addition, thermal annealing can effectively reduce the concentration of all the detected micro defects in the sample, and LIDT of the samples can be enhanced further after laser sub-threshold annealing. • KDP single crystals were obtained using the “point seed” rapid growth technique. • The relationship between laser-induced damage threshold and the concentration of micro defects is established. • The synergistic effect of thermal annealing and laser sub-threshold annealing is confirmed. • Enhanced laser-induced damage competence and laser-induced damage mechanism of the samples has been discussed.

Simulation of Austenite Formation During Continuous Heating from Low Carbon Martensite with Poly-dispersed Cementite

The nucleation and growth of austenite during continuous heating in plain carbon martensite is simulated using classical nucleation and diffusion growth theories assuming that austenite is nucleated on cementite particles at prior austenite grain boundaries and martensite packet, block, and interlath boundaries. A critical nucleus model on the spherical substrate was modified to take into account the influence of the boundary energy on which cementite particles formed. Simulations were carried out using the particle size distribution of cementite measured in an Fe-0.2 mass pct C alloy heated to near eutectoid temperature (Ae1). Austenite nucleation stopped in a very short time regardless of boundary site or particle size of cementite due to the fast decrease in carbon supersaturation and the depletion of nucleation sites. The fraction of austenite nucleated on cementite at prior austenite boundaries and martensite packet boundaries etc was much greater than that nucleated on cementite at interlath boundaries. While cementite particles dissolved quickly after austenite was nucleated, a large proportion of cementite particles at lath boundaries remained undissolved until they disappeared at 30 °C to 40 °C above Ae1. The evolution of austenite grain size was also simulated after austenitization was completed, and compared with experiment.

Crystal Growth Hysteresis in Spiral Growth

We demonstrated numerical simulations of impurity-induced crystal growth hysteresis in spiral growth. The numerical scheme combines two different methods: the phase-field method for step dynamics and the Monte Carlo method for random impurity adsorption. We manually changed the supersaturation (down and up) and repeated this cycle to monitor the time variation of the normal growth rate. We found that the growth rate suddenly drops to almost zero as the supersaturation decreases, and it swiftly recovers as the supersaturation subsequently increases. We confirmed that the critical supersaturation at which the growth rate recovered is distinguishably larger than that at which the crystal growth stopped. The critical supersaturations were found to be consistent with those predicted by the mean field theory for spiral growth if the period of the down-and-up cycle of supersaturation was chosen appropriately. We also applied the mean field theory to the observed hysteresis loops to evaluate some physical quantit...

Reaction coordinates and rate constants for liquid droplet nucleation: Quantifying the interplay between driving force and memory

In this work, we revisit the classic problem of homogeneous nucleation of a liquid droplet in a supersaturated vapor phase. We consider this at different extents of the driving force, or equivalently the supersaturation, and calculate a reaction coordinate (RC) for nucleation as the driving force is varied. The RC is constructed as a linear combination of three order parameters, where one accounts for the number of liquidlike atoms and the other two for local density fluctuations. The RC is calculated from biased and unbiased molecular dynamics (MD) simulations using the spectral gap optimization approach "SGOOP" [P. Tiwary and B. J. Berne, Proc. Natl. Acad. Sci. U. S. A. 113, 2839 (2016)]. Our key finding is that as the supersaturation decreases, the RC ceases to simply be the number of liquidlike atoms, and instead, it becomes important to explicitly consider local density fluctuations that correlate with shape and density variations in the nucleus. All three order parameters are found to have similar barriers in their respective potentials of mean force; however, as the supersaturation decreases, the density fluctuations decorrelate slower and thus carry longer memory. Thus, at lower supersaturations, density fluctuations are non-Markovian and cannot be simply ignored from the RC by virtue of being noise. Finally, we use this optimized RC to calculate nucleation rates in the infrequent metadynamics framework and show that it leads to a more accurate estimate of the nucleation rate with four orders of magnitude acceleration relative to unbiased MD.

Epidote spherulites and radial euhedral epidote aggregates in a greenschist facies metavolcanic breccia hosting an UHP eclogite in Dabieshan (China): Implication for dynamic metamorphism

AbstractEpidote spherulites are identified in a greenschist facies metavolcanic breccia enclosing a body of coesite-bearing eclogite at Ganghe in the Dabie ultrahigh-pressure metamorphic belt, east-central China. The epidote spherulites are formed by fibrous, radially arranged, and rare earth element (REE)-rich epidote crystals (ΣREE = 0.13–0.36 (or slightly higher) cations per formula unit, cpfu) and interfibrillar REE-poor epidote (ΣREE ≤ 0.10 cpfu). Some of the epidote spherulites are overgrown by radially arranged euhedral epidote crystals, which also form aggregates around preexisting quartz, plagioclase, and/or epidote. The epidote grains in such aggregates display oscillatory zoning, with REE content varying from a negligible amount to about 0.44 cpfu. Epidote also occurs as REE-poor individual euhedral crystals about the radial epidote aggregates or form loose clusters of randomly oriented crystals. Thermodynamic modeling of the mineral assemblages in the plagioclase pseudomorphs and in the matrix shows that they formed at greenschist facies metamorphic conditions (435–515 °C and 5–7 kbar). The epidote spherulites and radial euhedral epidote aggregates, however, do not belong to these assemblages and are non-equilibrium textures. They imply crystal growth under large degrees of supersaturation, with relatively low ratios of the diffusion rate (D) to the crystal growth rate (G). At low D/G ratios, spiky interfaces are favorable for diffusion-controlled growth and the resultant texture is a collection of spikes around a growth center, forming a spherulite. The change of epidote texture from spherulite to radial euhedral crystal aggregate implies a decrease of supersaturation and an increase of D/G, such that the crystal morphology was controlled by its crystallographic structure. The crystallization of the individual epidote grains corresponds to a further drop of supersaturation and a further increase of the D/G ratio, approaching to the equilibrium conditions. Transiently higher P-T conditions are inferred from the spherulite-forming reactions, relative to the P-T estimates for the equilibrium assemblages. The fibrous crystals in the spherulites having relatively large interfacial energies would inevitably adjust their shapes to equilibrium ones with low interfacial energies if the P-T-H2O conditions were maintained for a sufficiently long period of time. The non-equilibrium epidote aggregates likely formed in response to P-T and fluid pulses, possibly related to seismicity.

Limitations during Vapor Phase Growth of Bulk (100) 3C-SiC Using 3C-SiC-on-SiC Seeding Stacks.

The growth of 3C-SiC shows technological challenges, such as high supersaturation, a silicon-rich gas phase and a high vertical temperature gradient. We have developed a transfer method creating high-quality 3C-SiC-on-SiC (100) seeding stacks, suitable for use in sublimation “sandwich” epitaxy (SE). This work presents simulation data on the change of supersaturation and the temperature gradient between source and seed for the bulk growth. A series of growth runs on increased source to seed distances was characterized by XRD and Raman spectroscopy. Results show a decrease in quality in terms of single-crystallinity with a decrease in supersaturation. Morphology analysis of as-grown material indicates an increasing protrusion dimension with increasing thickness. This effect limits the achievable maximal thickness. Additional polytype inclusions were observed, which began to occur with low supersaturation (S ≤ 0.06) and prolonged growth (increase of carbon gas-species).

Crystallization of α-glycine by anti-solvent assisted by ultrasound.

Crystallization of α-glycine by addition of an anti-solvent (ethanol) assisted by ultrasound is studied. The experiments of crystallization are conducted at 303.15 K in a solution of 150 ml with continuous agitation by a magnetic rod. Ultrasound is then applied at powers ranging from 8 to 41 W thanks to an ultrasonic horn at 20 kHz. The supersaturation ratio (S) is followed throughout all the experiment. At the end of the experiment, the suspension is filtered, the solid is washed with ethanol and dried at 333.15 K. The resulting crystals are characterized by their final size distributions measured by laser granulometry, their morphologies observed by scanning electronic microscope (SEM) and their crystalline structures by differential scanning calorimetry (DSC). The influence of ultrasonic power (continuous 13, 28 and 40 W or pulsed modes), measured by calorimetry method, is studied for different addition rates (0.05 to 0.36 g of ethanol/min). Ultrasound permits to reduce the metastable zone width and to decrease the size of crystals due to an increase of the nucleation rate. The rate of de-supersaturation is higher in presence of ultrasound, inducing a higher nucleation rate, a higher growth rate or both. At 40 W, the decrease of supersaturation is faster, and the crystallization is finished in 40 min instead of 80 min (at 13 and 28 W) or 120 min without ultrasound. The use of pulsed ultrasound (50 on/50 off) is interesting from an economic point of view because similar results are obtained: comparable size distributions and resembling concentration profiles.

Effects of Total Dissolved Gas Supersaturation in Fish of Different Sizes and Species.

Two endemic fish in the upper Yangtze River, the Rock Carp (Procypris rabaudi) and Prenant’s Schizothoracin (Schizothorax prenanti), were used as research objects in this study to assess the effects of total dissolved gas (TDG) supersaturation on fish of varying sizes. Fish were exposed to TDG-supersaturated water at the levels of 145, 140, 135, 130, and 125%. The results showed that fish swam slowly, responded clumsily, and then exhibited spiral swimming performance after a period of exposure to TDG-supersaturated water. Fish exhibited exophthalmos, body swelling, gill bleeding, and caudal fin bleeding when they died in the TDG-supersaturated water. With the increase in TDG supersaturation, the tolerance capacity of fish to supersaturated TDG significantly reduced. At high supersaturation, the difference in survival time between species was not significant, while fish with smaller sizes showed greater tolerance capacity. At low supersaturation, the tolerance capacity of fish was mainly affected by species, and the influence of size was relatively small. With the decrease in TDG supersaturation, the catalase (CAT) activity first increased and then decreased. Rock Carp displayed significantly less activity than Prenant’s Schizothoracin on exposure to TDG-supersaturated water. At high supersaturation levels, the CAT activity of Prenant’s Schizothoracin of small size was greater than that of large Prenant’s Schizothoracin. In contrast, small Prenant’s Schizothoracin showed less CAT activity at low TDG levels than did large individuals.

Calculating free energy profiles using entropy as a reaction coordinate: Application to water nucleation

We identify the nucleation pathway for a liquid droplet of a water-like system. In order to calculate the free energy barrier associated with the droplet formation, we use the recently developed μVT-S simulation method to unravel the nucleation process. We analyze the interdependence between droplet size, entropy and free energy of nucleation. Three key features emerge: the droplet size increases as entropy decreases during the process, the nucleation free energy increases as supersaturation decreases, and the nucleation free energy increases as T decreases. This method can be readily applied to calculate free energy barriers of activated events with entropy as the reaction coordinate.

Crystal morphological evolution of growth and dissolution of curve-faced cubic diamonds from placers of the Anabar diamondiferous region

In this paper, we consider an ontogenic model for the formation of morphological types of growth and dissolution of cubic diamonds of variety II by Yu.L. Orlov from placers of the Anabar diamondiferous region. The following ontogenic domains of crystals and corresponding evolutionary stages of growth accompanying a general decrease in supersaturation in the crystallization medium were distinguished: microblock mosaic cuboids with defects produced by the mechanism of rotational plastic deformation–cuboids with linear translation deformations–cuboids and antiskeletal growth forms of cuboids composed of octahedral growth layers–pseudocubic growth forms of a flat-faced octahedron. The crystal morphological evolution of cuboids during the bulk dissolution of individuals in fluid-bearing melt transporting them to the surface was traced. The investigation of transitional forms of cuboid diamond dissolution showed that the final form of diamond dissolution is a rounded tetrahexahedroid independent of the combination of cuboid faces with subordinate faces of octahedron, rhombododecahedron, and tetrahexahedron observed on resorbed crystals of cubic habit. It was found that the final stages of cuboid dissolution produced disk-shaped microrelief features on the diamond surface in the form of randomly distributed ideal rounded etch pits resulting from interaction with microscopic cavitation gas bubbles released during the decompression of ascending kimberlite melt.

Dissolution–Recrystallization of (Mg,Fe)CO3 during Hydrothermal Cycles: FeII/FeIII Conundrums in the Carbonation of Ferromagnesian Minerals

Crystallization experiments were performed at high supersaturation to obtain metastable (Mg,Fe)CO3 precipitates and study their evolution during hydrothermal heating in a nitrogen atmosphere. The primary (Mg,Fe)CO3 solids undergo a dissolution–recrystallization process driven by two forces: the preferential partition of Fe2+ toward the (Mg,Fe)CO3 solid solution and the oxidation of aqueous Fe2+ species to form Fe(III)-bearing solids. Under limited oxygen supply, the oxidation of Fe2+ is a slow process, particularly in the presence of chlorine and inorganic carbon. In absence of oxidation, the initial solid solution should become increasingly Fe-rich as the supersaturation decreases and the system approaches equilibrium. Here, the secondary (Mg,Fe)CO3 solids become the wrong way round, Mg-rich. The gradual oxidation of the aqueous Fe2+ species eventually leads to precipitation of magnetite, which is also metastable because the aqueous solution is maximally supersaturated with respect to hematite. In most c...

The details of the formation of CuCl nanoparticles in photochromic glass

The details of the formation of CuCl nanoparticles in the sodium alumina-borosilicate glass for different methods of thermal treatment of the samples are studied by exciton thermal analysis. It is revealed that the formation of the CuCl phase in glass depends on the heating rate of the samples to the predetermined temperature of isothermal annealing. The concentration of the nucleating centers of the CuCl phase reaches its peak value at 600°C during slow (60 min) heating up to 650°C, due to the fast increase of the critical size of particles of the phase as a result of the fast temperature increase and the rapid decrease of supersaturation in glass. As a result, the formation of new CuCl nucleation centers terminates above 600°C, and part of the centers formed earlier whose size is less than critical dissolve, which results in the monotonic decrease of the CuCl particle concentration.

Formation of radiation induced precipitates in VVER RPV materials

This paper presents an analysis of experimental results received in course of research of copper-enriched precipitates (Cu-precipitates) and nickel-manganese-silicon clusters (Ni-Mn-Si clusters), which are formed in steels of VVER-type reactor pressure vessels (RPVs) under neutron irradiation. Based on this analysis, a hypothetical model is suggested for cluster formation in course of evolution of a cascade region. The model presumes cluster formation in two stages. At the first stage, in course of cascade region crystallization, a stable cluster is formed in the center of the cascade region, which consists of vacancies and Cu atoms following the mechanism of the inverse Kirkendall effect. At the second stage, diffusion of Ni, Mn and P atoms with a flow of vacancies from the matrix takes place to form a cluster. The size of a cluster is limited by a balance of vacancies' flows entering and leaving the cluster. The paper also considers a possibility of stabilization of atomic-vacancy cluster due to uneven distribution of Ni, Mn and P atoms, which explains dependence of cluster density on the content of these elements. Kinetics of cluster formation and evolution presumed by suggested model is analyzed. It is demonstrated that a fall in cluster density and an increase in their size under high irradiation doses may be caused by a decrease of matrix supersaturation with vacancies resulting from high density of dislocation loops.

Post‐crystallization cooling behavior of aqueous supersaturated ammonium dihydrogen phosphate solutions containing acetone and methanol antisolvents added at different rates

Experimental results of post‐crystallization cooling behavior of aqueous supersaturated ammonium dihydrogen phosphate (ADP) solutions containing acetone and methanol antisolvents fed at different rate RA are described and discussed. The supersaturated solutions were contained in a double‐walled crystallizer connected to a thermostating arrangement maintaining the temperature at 30 °C. It was found that: (1) there is a steady decrease in temperature Ts of aqueous ADP solutions with increasing time t, which follows Newton's law of cooling, with constant K as characteristic of solution composition and its value for a system increases with an increase in RA, and (2) at a particular acetone and methanol feeding rate RA, the value of constant K for aqueous ADP solutions is much higher than that obtained from the data of decrease in the temperature Tm of pure water. The experimental results are discussed from consideration of a steady decrease in solution supersaturation with increasing t as a result of diffusion of ions/molecules involved in transporting heat from aqueous ADP solutions contained in the crystallizer to the thermostating system.

Microwave Assisted Synthesis of Ferrite Nanoparticles: Effect of Reaction Temperature on Particle Size and Magnetic Properties.

The preparation of ferrite magnetic nanoparticles of different particle sizes by controlling the reaction temperature using microwave assisted synthesis is reported. The iron oxide nanoparticles synthesized at two different temperatures viz., 45 and 85 °C were characterized using techniques such as X-ray diffraction (XRD), small angle X-ray scattering (SAXS), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The average size of iron oxide nanoparticles synthesized at 45 and 85 °C is found to be 10 and 13.8 nm, respectively, and the nanoparticles exhibited superparamagantic behavior at room temperature. The saturation magnetization values of nanoparticles synthesized at 45 and 85 °C were found to be 67 and 72 emu/g, respectively. The increase in particle size and saturation magnetization values with increase in incubation temperature is attributed to a decrease in supersaturation at elevated temperature. The Curie temperature was found to be 561 and 566 0C for the iron oxide nanoparticles synthesized at 45 and 85 °C, respectively. The FTIR spectrum of the iron oxide nanoparticles synthesized at different temperatures exhibited the characteristic peaks that corresponded to the stretching of bonds between octahedral and tetrahedral metal ions to oxide ions. Our results showed that the ferrite nanoparticle size can be varied by controlling the reaction temperature inside a microwave reactor.