Climate change and the continual rise in cooling demand means more efficient and environmentally friendly refrigeration technologies are required more than ever. One attractive route to reducing future demand is to improve adsorption refrigeration technologies based on natural refrigerants such as ammonia. The choice of ammonia adsorbent plays an important role in achieving improved refrigeration efficiency and suitable operating conditions. This paper reports a detailed study on the role of pore size on thermal efficiency, desorption temperature and cooling capacity of ammonia–carbon adsorption refrigeration systems. Systematic Monte Carlo simulations were conducted to study ammonia adsorption in carbon slit-pores with pores sizes ranging from 0.5 nm to 3.0 nm. Simulations were carried out at temperatures between 0°C and 50°C and pressures up to 15.0 bar. It is found that nanoporous carbon with very small pore sizes is not a good adsorbent for thermally efficient adsorption refrigeration systems. However, carbon mesopores can provide higher refrigeration capacities and coefficients of performance together with lower desorption temperatures, thus offering the possibility of relying on low-grade thermal waste heat to drive the refrigeration process.

We report here the optical, photoluminescence (PL), and dielectric properties of Cd0.40Ni0.60ZnO2 nanocomposites annealed between 200 and 600 degrees C. An increase in annealing temperature (T-ann) up to 600 degrees C correlates with a gradual increase in the crystallite and particle sizes. The surface area, pore radius, and pore volume are increased as T-ann increases from 200 degrees C to 300 degrees C, and then decreased, but still higher than of 200 degrees C. Similar behaviors were obtained for the absorbance carrier density, photocatlytic efficiency, degradation rate, PL intensity, dielectric constant, dielectric loss, ac conductivity, F-factor, series resistance, and electronic polarizability. While the energy gap, binding energy, impedance of grains and their boundaries, and effective capacitance show an opposite behavior. The relaxation times at the peak of dielectric parameters are between 11.54 and 159.24 ns and between 35.23 and 24273.73 ns, respectively. The Cole-Cole plot shows a single semicircle at T-ann < 400 degrees C and two successive semicircles at T-ann > 500 degrees C. The energy of PL degrees f visible emissions is independent on the chosen T-ann. These findings indicated that the nanocomposite annealed at 300 degrees C can be used for water purification, telecommunications, solar cells, supercapacitor, and white light-emitting diodes (LEDs).

The structural, optical, and photocatalytic properties of Cd0.4Mn0.6XO nanocomposites with 50 wt% of X were investigated (X denotes ZnO, SnO, CuO, Al2O3, Fe2O3, NiO, and CoO). The crystal structure of Cd0.4Mn0.6XO nanocomposites is composed of the monoclinic Cd2Mn3O8 phase, along with other individual phases dependent on the type of X dopant. The crystallite sizes are between 11.07 nm for CoO and 23.65 nm for ZnO, whereas the particle sizes are between 9.75 nm for ZnO and 35.61 nm for Fe2O3. The SnO, NiO, and CoO nanocomposites had the highest values of the effective surface area of 29.71, 26.3, and 24.1 m(2)/g, respectively. The NiO and SnO nanocomposites had the highest and lowest absorbance, respectively, notably at wavelength below 400 nm. SnO, NiO, CuO, and Fe2O3 nanocomposites have the highest values of energy gap (Eg > 2 eV), whereas CoO, ZnO, and Al2O3 nanocomposites have the lowest Eg values (< 2 eV). The SnO nanocomposite exhibited the highest values of refractive index, q-factor, lattice dielectric constant (epsilon L), free carrier density (Nm & lowast;), and optical/electrical conductivity when compared to the other Cd0.4Mn0.6XO nanocomposites. Interestingly, the values of epsilon L and Nm & lowast; were enhanced to 21.2 and 4.9 x 10(57) cm(-3)g(-1) for SnO nanocomposite, followed by NiO and Fe2O3 nanocomposites. The photodegradation efficiency towards methylene blue (MB) using the Cd0.4Mn0.6XO catalysts after 3 h of UV-visible irradiation equals 97.94, 76.43, 74.43, 71.32, 65.98, 62.86, and 48.55 % for ZnO, NiO, SnO, Fe2O3, Al2O3, CuO and CoO nanocomposites, respectively. The photocatalytic performance of Cd0.4Mn0.6XO catalysts towards MB was compared to earlier investigations and a scavenger test was performed to validate the formation of reactive oxygen species. The features of Cd0.4Mn0.6XO nanocomposites are convenient for light-emitting diodes, solar cells, reduced electronic noise, high-power operation, and water purification.

Climate change and the continual rise in cooling demand means more efficient and environmentally friendly refrigeration technologies are required more than ever. One attractive route to reducing future demand is to improve adsorption refrigeration technologies based on natural refrigerants such as ammonia. The choice of ammonia adsorbent plays an important role in achieving improved refrigeration efficiency and suitable operating conditions. This paper reports a detailed study on the suitability of zeolites as an adsorbent of ammonia in refrigeration applications. Systematic Monte Carlo simulations were conducted to study ammonia adsorption in five high-silica zeolites with a wide range of pores sizes and porosities. Simulations were carried out at temperatures between -50 and 50°C and pressures up to 4.0 bar. It is found that zeolites, in particular the ones with large porosities, could be very good ammonia adsorbents for adsorption refrigeration applications, since their use allows for large refrigeration capacities and tuneable operating conditions with good coefficients of performance (COP).

We report the photolumenses (PL) and dielectric measurements of Cd (1-x) Co x O nanocomposites with (0.00 <= x <= 1.00). It is found that an increase in x correlates with a significant change in crystallite size, particle size, porosity, Debye temperature, Young ' s modulus, q -factor, binding energy, impedance of grains and their boundaries. The samples with x = 0.50 or 0.60 show an adverse change in the behavior of these parameters. We could not evaluate any shift in the wave length of PL emissions, although they are different in intensities . The samples of x = 0.40 and 1.00 show more visible emission colors at 640, 678, 716, and 791 nm. The x = 0.00 sample shows a negative dielectric constant ( epsilon \ ), but it crossovers to positive for the other values of x. epsilon \ was gradually decreased as frequency increased up to 10 KHz, after which it nearly saturated except x = 0.80, in which it linearly decreased and never saturated. The ac conductivity decreased gradually against x such that the type of conduction is dependent on the chosen x. The Cole -Cole plot shows a straight line for x = 0.00 and arcs for x = 0.20 and 0.60, and a complete semicircular for x = 0.40, 0.50, 0.80 and 1.00. Furthermore, the effective capacitance was 9260 mu F for x = 0.00, but it drops to 0.013 mu F for x = 0.40, whereas the vice is true for bulk resistance. These results lend a reasonable certainty to the assertion that Co substitutes for Cd and make them potential prospects for devices such as diodes that emit light, cathode-luminescence displays, integrated circuits, Li-battery and supercapacitors.

In the present study, the structural, optical, and magnetic properties of (ZnSn)1-xCoxO nanocomposites (NCs) were reported. The transmission electron microscope (TEM) images of ZnSnO NCs showed mixed nanorods and nanosheets morphologies that completely transformed to mostly nanocubes with Co-ions incorporation. The optical band gap (Eg) of nanostructured ZnO, SnO, and ZnSnO NCs was 3.2, 4.5, and 3.9 eV, respectively. The estimated Eg value of all (ZnSn)1-xCoxO NCs was lower than the undoped ZnSnO NCs. The nanostructured ZnO revealed poor room-temperature ferromagnetic (RTFM) behavior whereas nanostructured SnO exhibited paramagnetic behavior at low magnetic field strength followed by diamagnetic behavior at high magnetic field strength. The (ZnSn)1-xCoxO NCs exhibited strong improvement in the RTFM, where the hybrid (ZnSn)60Co40O NCs exhibited the highest saturation magnetization (Ms) of 2 emu & sdot;g  1. This value was 5-times higher than the undoped ZnSnO NCs and 2-orders of magnitude higher than the pure ZnO phase. However, with increasing Co-content up to 50 %, the Ms was reduced to 1.16 emu & sdot;g  1 demonstrating the corruption of RTFM. The present study indicated the importance of composition utilization for tuning physical properties of (ZnSn)1-xCoxO NCs and improving the performance of these NCs in optoelectronic and spintronics applications.

We use Monte Carlo simulations to investigate the effect of incorporating calcium chloride salt into nanoporous carbon on the performance of an ammonia-carbon adsorption refrigeration system. Simulations of ideal carbon slit-pores with pore sizes of 1, 2, and 3 nm, each containing calcium chloride with ion densities of 0.0, 0.25, and 0.5 nm(-3), were carried out at temperatures between 0 and 30 degrees C and ammonia pressures up to 15.0 bar. The results reveal that ideal 1 nm pores are able to achieve a good refrigeration performance using waste heat below 100 degrees C to drive the process, but adding salt to these pores increases the waste heat temperature required beyond 100 degrees C. However, ideal 2 nm pores require the addition of 0.25 nm(-3) salt to achieve a similar performance, while the 3 nm pores were unable to achieve a satisfactory refrigeration performance. Considering that real nanoporous carbons usually feature a variety of specific adsorption sites and non-ideal geometries that should have a similar impact to adding salt, these results indicate that nanoporous carbons with pores in the range of 1-2 nm are likely to hold the most promise for adsorption refrigeration applications and that the addition of salt may not always be helpful.

Herein, structural, surface area, optical, photocatalytic, and magnetic properties of a new Cd1-xSnxFe2O4 nanocomposites (1 >= x >= 0), synthesized by the hydrothermal approach were investigated. The nanocomposite formation is confirmed by X-ray diffraction analysis (XRD), Transmission electron microscopes (TEM), Fourier transform infrared (FTIR), Inductively coupled plasma (ICP), and Energy dispersive X-ray (EDX) analyses. The XRD findings reveal the formation of Fe2O3 at x = 0, 0.2, 0.4, and 1, while the Fe3O4 phase at x = 1 besides the spinel CdFe2O4 phase for x = 0.6 and 0.8, and rutile SnO2 phase for x >= 0.8. The crystal structure, e.g., lattice parameters, bond length, cell volume, theoretical density, crystallite size, dislocation density, and microstrain are remarkably influenced by elemental ratios. The average crystallite size of composites declined to 15.2 +/- 4 nm as x increased to 0.4, then grew to 40.5 +/- 4 nm at x = 0.6, and then decreased to 21 +/- 10 nm at x = 1. The particle morphologies were deduced, and crystal structures were confirmed by analyzing field-emission scanning electron microscope (FE-SEM), and TEM micrographs. FTIR confirmed the presence of metal oxide bands for all nanocomposites. The surface area was calculated via the Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) theories to the N-2 adsorption-desorption isotherm and equals 10.5, 20.3, 17.1, and 25.2 m(2)/g at x = 0, 0.4, 0.6, and 1, respectively. The magnetic properties of the Cd1-xSnxFe2O4 nanocomposites were studied by vibrating-sample magnetometry (VSM) technique, which displayed their ferromagnetic behaviors. The addition of Sn2+ into the composite improved the magnetic saturation from 0.42 to 34.7 emu/g by changing x from 0 to 0.4 then was reduced to 5.9 emu/g at x = 1 which well matched with the behavior of total pore volume. Furthermore, the indirect optical band gap (E-g(in)) was increased, e.g., E-g(in) equals 1.22, 1.82, 1.88, and 2.08 eV for x = 0, 0.4, 0.6, and 1, respectively. Methylene blue photocatalytic performance was investigated, and the maximum degradation efficiency of 44.33 % was detected using Cd1-xSnxFe2O4 at x = 0.8 under UV-visible irradiation for 160 min.

Structural, mechanical and ferromagnetic characteristics of hydrothermally synthesized Cd0.4Mn0.6XO nanocomposites were investigated. The characterization of Cd0.4Mn0.6XO was accomplished using XRD, TEM, FTIR, photoluminescence and VSM techniques. The XRD showed the formation of monoclinic Cd2Mn3O8 alongside other phases. The crystallite size has no systematic trend against the valence state of ions. The particle size has minimum value (9.75 nm) for ZnO, and maximum values of 31.39 nm and 35.61 nm were observed for Al2O3 and Fe2O3, respectively. Similarly, typical enhancements are achieved for the mechanical and ferromagnetic parameters, e.g. they are increased when ZnO is replaced by Al2O3 and significantly enhanced by Fe2O3. In contrast, they were reduced by the other X, but they are still higher than ZnO. The photoluminescence of Cd0.4Mn0.6XO shows violet, blue, green, and orange emissions. The reported results indicate a strong correlation between the mechanical and ferromagnetic properties of nanocomposites against the particle/crystallite sizes and valence state.

We report the structural and magnetic properties of zinc -nickel ferrites (ZNF), Zn 1- x Ni x Fe 2 O 4 , nanoparticles synthesized by the hydrothermal method with 0.0 <= x <= 1.0. The X-ray powder diffraction of Zn 1- x Ni x Fe 2 O 4 shows the formation of a single spinel phase of ZnFe 2 O 4 or NiFe 2 O 4 . The lattice parameter and unit cell volume decreased slightly as the x ratio increased, whereas the average crystallite size ranged from 9.55 to 22.7 nm. The nanoparticles ' morphology consists of small cubic and spherical particles with an average size increasing up to x = 0.6 and dropping at further increases of x . The assigned peaks obtained by the Fourier -transform infrared spectroscopy at 556 - 592 cm -1 verified the formation of metal (Zn, Ni, and Fe) oxides. The surface area, pore radius, and total pore volume were estimated using the Brunauer-Emmett-Teller (BET) and Barrett-JoynerHalenda (BJH) theories and found to be dependent on the composition of the synthesized nanoferrites. Interestingly, we observed the largest surface area, S BET , of 264 +/- 28 m 2 g -1 at x = 0.6, which is three times higher than the other samples. The Zn 1- x Ni x Fe 2 O 4 nanoferrites exhibited ferromagnetic behavior at room temperature with a saturation magnetization between 30.3 +/- 0.01 and 126 +/- 0.07 emu g -1 . We found a possible link between maximum retentivity, corrective filed, and squareness with the surface area, especially at x = 0.6. The magnetic behavior at x = 0.4 could be attributed to the sample ' s larger crystallite/particle sizes as compared to the other samples. Our results of the synthesized Zn 1- x Ni x Fe 2 O 4 nanoparticles demonstrate the wide applicability of the ZNF nanostructures in magnetic storage as well as other applications that demand ferrite materials with a larger surface area.

(ZnSn)1-xCuxO nanocomposites (NCs) with nanorods and nanosheet morphologies were synthesized by a facile hydrothermal technique. (ZnSn)1-xCuxO NCs exhibited a gradual band gap redshift from UV to visible spectral region with increasing Cu-content. The room temperature magnetic hysteresis loop indicated the improvement of room temperature ferromagnetic (RTFM) behavior of (ZnSn)1-xCuxO NCs compared with nanostructured ZnSnO NCs induced by the exchange interaction of Cu-bound polarons with the localized spins and free carriers. The (ZnSn)60Cu40O NCs exhibited the highest saturation magnetization (Ms) of 0.539 emu·g−1. Further increase in Cu-content resulted in the deterioration of crystalline domains and the reduction of Ms to 0.259 emu·g−1. This behavior revealed that the electronic and magnetic properties of (ZnSn)1-xCuxO NCs were so sensitive to the dopant concentration that need to be utilized for improving their performance as good candidate NCs for spintronic applications.

Here, we investigate the morphological and magnetic characteristics of Cd(1-x)CoxFe2O4 nanoferrite system with (0.0 <= x <= 1.0 mole), prepared by the hydrothermal technique. The structure of the synthesized nanoferrite as resulted from the X-ray diffraction (XRD) reveals that cadmium-cobalt nanoferrites possess fcc CdO, hexagonal Fe2O3, and hexagonal CoFe2O4 phases. The average crystalline size is ranged from Dav = 10.9 +/- 0.9 nm to Dav = 33.3 +/- 3.0 nm as determined by the Scherer formulation. The average grain size was extracted from High Resolution Transmission Electron Microscope (HRTEM) scans. The metal-oxide (M-O) bonds were confirmed with the Fourier Transform Inferred (FTIR) technique. The hysteresis curves of the prepared samples indicate that the system exhibits ferromagnetic properties. Interestingly, the saturation magnetization gradually increases with the Co content from 0.42 to 60.6 emu g-1 corresponding to x = 0.0 and x = 1.0, respectively. This remarkable increase represents the highest reported value for this system so far. Excluding the concentration x = 0.0, the saturation magnetization increases linearly with Co concentration. Although few earlier works reported scattered trends on the relation between saturation magnetization and Co concentration in Cd(1-x)CoxFe2O4 nanoferrites, the linearity of the relation is observed for the first time.

We report here the effect of annealing temperature T-ann (200-600 degree celsius) on the structural, mechanical, and magnetic properties of Cd0.40M0.60ZnO2 (M = Mn, Ni) nanocomposites. The increase in Tann correlates with a significant change in unit cell volume (V), porosity (PS) crystallite size (D-hkl), particle size (r), Debye temperature (theta(D)) and elastic modulus (Y). The values of V, r, theta(D) and Y are higher for the Mn-series than Ni. While the values of PS and D-hkl are higher for Mn than Ni at T-ann <= 300 degree celsius, and the reverse is true at T-ann <= 400 degree celsius. The average particle size is 10.6 +/- 2.4 nm for Mn-series, but it is decreased to 7.5 +/- 4.0 nm for Ni-series, indicating quantum -dot size. Surprisingly, both series exhibit ferromagnetic behavior as Tann increases to 600 degree celsius, but the magnetization parameters for the Mn series are higher than those for Ni. Furthermore, the anisotropy field (H-a) is about 350 times higher than the corrective field (H-c), indicating hard magnetic materials. The switching field distribution (SFD) is increased by annealing, but it is higher for Ni-series than Mn. The considered nanocomposites would be useful for altering plastic deformation and spintronic devices.

The structural, optical, and magnetic qualities of Cd1-xMnxZnO2 nanocomposites with (0.00 <= x <= 1.00) are investigated and the paramagnetic ferromagnetic transition is explained. Two series (effect of annealing and composition) were synthesized using the hydrothermal method and then annealed for 3 h at annealing tem-peratures (Tann) of 400 degrees C or 600 degrees C. It is found that an increase in either x or Tann correlates with significant change in unit cell volume (V), crystallite size (Dhkl), Debye temperature (theta D) and energy gap (Eg). Further, the samples at x = 0.60 show a sudden change or inflection point in the behavior of these parameters is detected. Furthermore, the values of Eg and Dhkl for the x = 0.60 sample are independent of the chosen Tann. The weight percent of oxygen increased as x increased, as well as it was higher at 600 degrees C than at 400 degrees C. The value of Dhkl at x = 0.40 was increased by increasing Tann from 20.7 nm to 26.3 nm. Surprisingly, both series of samples exhibit weak paramagnetic properties as x increases to 0.40. However, increasing x to 0.60 yields a strong ferromagnetic signature for both series as well as unusual unsaturated magnetizations of 4.20 and 1.25 emu/g. However, with a larger further than of x above 0.60, the behavior returns to a strong paramagnetic behavior, but with a small percentage of residual hysteresis. These novel outcomes open the way for a possible mechanism for room temperature ferromagnetic (RTFM) and strongly recommend the use of Cd1-xMnxZnO2 nanocomposites, for magnetic imaging, and spintronic devices.

We report here the structural, optical, photoluminescence (PL), and magnetic investigation of Zn 1−x−y Fe x M y O nanoparticles. The lattice constants and crystallite size are decreased by Fe, followed by a further decrease up to (Fe + M) = 0.30. A compressive stress is approved and the size of particle is between 180 and 277 nm and follows the sample order of ZnO, (Fe + Cu), (Fe + Ni), and Fe. Although a single value of energy gap (E g ) is found for pure and Fe-doped ZnO, two values of E g (E gh and E gl ) are found for the co-doped samples. The E g is generally increased by Fe, followed by a further increase for the Cu-series, whereas it is decreased for the Ni-series. The refractive indices n K and n T proposed by different methods are generally decreased by Fe, followed by a further decrease for both series. Although Fe doped ZnO depressed the density of carriers (N/m*), it increased again for the co-doped samples. The residual dielectric constant ϵ L is decreased by Fe, followed by an increase for the Cu-series, but it is decreased for the Ni-series. The loss factor tan δ increases slightly with Fe, followed by an increase for the Ni-series, but it decreases in the Cu-series. A significant depression of optical conductivity σ opt by Fe was obtained, followed by a further decrease which is higher for the Cu-series. The PL shows four visible emissions. Interestingly, an IR emission at about 825 nm is only obtained for the co-doped samples. Furthermore, the blue emission (I blue ) was higher than UV (I UV ), [(I blue /I UV ) > 1], but it is greater for the Ni series than the Cu. Although ZnO exhibits diamagnetic behavior, the Fe and co-doped samples exhibit ferromagnetic with higher magnetization for the Ni-series than the Cu. The current results recommend the co-doped samples in nanoscale for some of advanced devices.

Here, we investigate the morphological and magnetic characteristics of Cd(1−x)CoxFe2O4 nanoferrite system with (0.0≤x≤1.0 mole), prepared by the hydrothermal technique. The structure of the synthesized nanoferrite as resulted from the X-ray diffraction (XRD) reveals that cadmium–cobalt nanoferrites possess fcc CdO, hexagonal Fe2O3, and hexagonal CoFe2O4 phases. The average crystalline size is ranged from Dav=10.9±0.9nm to Dav=33.3±3.0nm as determined by the Scherer formulation. The average grain size was extracted from High Resolution Transmission Electron Microscope (HRTEM) scans. The metal–oxide (M–O) bonds were confirmed with the Fourier Transform Inferred (FTIR) technique. The hysteresis curves of the prepared samples indicate that the system exhibits ferromagnetic properties. Interestingly, the saturation magnetization gradually increases with the Co content from 0.42 to 60.6 emu g−1 corresponding to x=0.0 and x=1.0, respectively. This remarkable increase represents the highest reported value for this system so far. Excluding the concentration x=0.0, the saturation magnetization increases linearly with Co concentration. Although few earlier works reported scattered trends on the relation between saturation magnetization and Co concentration in Cd(1−x)CoxFe2O4 nanoferrites, the linearity of the relation is observed for the first time.

Structural, morphological, FTIR, optical and photoluminescence (PL) measurements of Zn1-xRExO nanoparticles with RE = Y, La and x (0.00 ≤ x ≤ 0.20) are reported. The wurtzite structure is confirmed for all samples and the lattice parameters, Zn–O bond length, porosity, crystallite size, lattice strain and residual stress are increased by increasing x to 0.20, but they are higher for La samples than Y. The grain sizes are 180, 330, and 460 nm for the pure, Y and La samples. The addition of RE to ZnO generally shifts FTIR absorption peaks, Debye temperature, and elastic modulus to higher values, but the shift is higher for La samples than Y. Although excitonic energy is constant for all samples, the energy gap Eg was increased by increasing x to 0.20, but it is higher for La samples than Y. Furthermore, the dielectric lattice constant, density of charge carriers, and electrical conductivity are increased by increasing x to 0.10, followed by a decrease to 0.20. The opposite behavior is true for dielectric loss and optical conductivity. The PL intensity shows four continuous visible peaks of near UV, blue, green, and red. Interestingly, the intensity of blue emission is greater than that of near UV, such that [(Iblue/IUV)] > 1]. Furthermore, for x > 0.10 samples, there is another lowest intensity IR emission peak centred at 824 nm (1.507 eV). These results are well explained and strongly recommend the RE doped samples for the applications of optoelectronic and high-power operating devices. To our knowledge, the present investigation probably has never been reported elsewhere.

Ac dielectric measurements of Zn1−x−yFexMyO samples with different M, x and y were made against frequency (f) up to 10 MHz. It is found that addition of Cu beside Fe in ZnO decreased the porosity and average size of grains, whereas they are increased by addition of Ni in place of Cu. The real and imaginary parts of dielectric constant (ε′, ε″) and dielectric loss (tanδ) are generally decreased by Fe, followed by an increase/decrease for (Fe + Ni)/(Fe + Cu) samples. Furthermore, the conduction is electronic below 10 kHz for all samples, but it is changed to hole as f increases above 10 kHz. Generally, the binding energy Wm, minimum hopping distance (Rmin) and density of states at Fermi level N(EF) are slightly increased by Fe, followed by a decrease for the co-doped samples. Interestingly, the N(Ef) of the Zn0.9Fe.1O (S2) sample is sharply increased with f, goes to optimum at 28.7 Hz and then decreases. In addition, the F-factor, for solar cell design, was increased by increasing f, and it has the samples order of (Fe), (Fe + Ni), (Zn) and (Fe + Cu). A single semicircle could be obtained from the Cole–Cole plot and the impedance of grain Z\(G) and that of grain boundaries Z\(GB) are increased by Fe, followed by an increase/decrease for (Fe + Cu)/(Fe + Ni) samples. The radius of arc increases for Fe and (Fe + Cu) samples, revealing a decrease in capacitance, while vice versa for (Fe + Ni) samples. The arcs seem to be centered below the Z\ axis, indicating non-Debye relaxation of dipoles. These outcomes indicate that Fe and (Fe + Ni) samples shift the ZnO dielectric medium to higher values, and it is strongly recommended with Fe sample for solar cell design. In contrast, the (Fe + Cu) samples are recommended for high-frequency nonlinear optical devices due to their poor dielectric medium. To the best of our knowledge, the present systematic investigation may not be reported elsewhere.

Recent experiments with undersaturated aqueous glycine solutions have repeatedly exhibited the presence of giant liquid-like clusters or nanodroplets around 100 nm in diameter. These nanodroplets re-appear even after careful efforts for their removal and purification of the glycine solution. The composition of these clusters is not clear, although it has been suggested that they are mainly composed of glycine, a small and very soluble amino acid. To gain insights into this phenomenon, we study the aggregation of glycine in aqueous solutions at concentrations below the experimental solubility limit using large-scale molecular dynamics simulations under ambient conditions. Three protonation states of glycine (zwitterion = GLZ, anion = GLA, and cation = GLC) are simulated using molecular force fields based on the 1.14*CM1A partial charge scheme, which incorporates the OPLS all-atom force field and TIP3P water. When initiated from dispersed states, we find that giant clusters do not form in our simulations unless salt impurities are present. Moreover, if simulations are initiated from giant cluster states, we find that they tend to dissolve in the absence of salt impurities. Therefore, the simulation results provide little support for the possibility that the giant clusters seen in experiments are composed purely of glycine (and water). Considering that strenuous efforts are made in experiments to remove impurities such as salt, we propose that the giant clusters observed might instead result from the aggregation of reaction products of aqueous glycine, such as diketopiperazine or other oligoglycines which may be difficult to separate from glycine using conventional methods, or their co-aggregation with glycine.

In this work a new nanocomposite system of Cd(1_X)CoXO (0.0 < X < 1.0 mol) is presented. The nanocomposite system has been synthesized using the hydrothermal method. The composition of the synthesized system is confirmed with the EDX technique. The synthesis, structure, magnetic, and surface area properties of the synthesized Cd(1_X)CoXO nanocomposite system are reported. The structure has been studied with X-ray diffraction, TEM, and SEM, which confirms the formation of the nanocomposite. The new nanocomposite system of Cd(1_X)CoXO possess fcc CdO, fcc CdCoO, and fcc Co3O4 phases. Celref Unit-Cell refinement code was used to determine the lattice parameter (a, b and c), bond length (l), cell volume (V) and theoretical density (rho), while the average crystallite size (Dav), dislocation density (epsilon), and the microstrain (delta) was calculated using the Scherrer equation. The M _ O (metal-oxide) bonds were investigated with the FTIR technique. In addition, we analyze the magnetization curves and the mass magnetic susceptibility (chi mass) of the system. The surface area has been determined and discussed using Brunauer-Emmett-Teller method (BET). Lastly, the effect of Co2+ ions concentration on the above studies is discussed.