Chloride Crystals Research Articles

On the Transparency of Alkali-Halide Crystal in the Terahertz Spectral Range

The transmission of THz (to 3000 μm) radiation by alkali halide single crystals of sodium chloride (NaCl), potassium chloride (KCl), potassium bromide (KBr), and rubidium iodide (RbI), which are widely used in the IR spectral region, is studied. The spectral dependences of the absorption coefficients of these materials in the range of 0.9–3000 μm are determined. These materials are transparent in the range of 1000‒3000 μm, which makes it possible to use them in terahertz (millimeter) devices.

Innovative Way to Decrease the Water Consumption of Direct Evaporative Air Cooler

In the present study the existing direct evaporative coolers (DEC) is modified in such a way that DEC consume less amount of water and provide better cooling effect. In desert area, water consumption by air cooler is a serious problem. Therefore, the present study addressed this issue and primary objective of the study is to minimize the consumption of water. For this purpose, the property of the endothermic reaction is utilized. There are few salts that produce endothermic reaction if it is diluted in water. Those salt crystals absorb heat from the surrounding environment (water) and ultimately the temperature of the overall solution gets reduced. This cold solution is then passed through honeycomb cooling pad, as a result more amount of air can be cooled using the same volume of water as compared to the traditional air-cooler. Ammonium Chloride (NH4Cl), Ammonium Nitrite (NH4NO3) salts satisfy the basic criteria for the endothermic reaction but NH4Cl will be more useful to use in the air-coolers, as Ammonium Nitrite is costlier and also hazardous. A salt water separator arrangement also attached with modified air-cooler which will help to regenerate Ammonium Chloride crystal from solution with the help of solar energy. In this study, firstly discussed about proposed design of an air-cooler system, which is able to nicely handle chemical solution. Then compared the study with experimental outcome which have been carried out with and without using salt. From the result it has been observed that modified design of air cooler has great potential to improve the traditional air cooler in terms of cooling effect and water consumption.

Scintillation properties of Mn-doped methylammonium lead chloride crystals

Organic–inorganic perovskite materials with a bulk structure MAPbX3 (MA: methylamine, X: halogen) have attracted much attention in various applications such as solar cells, photodiodes, and radiation detectors. Herein, we synthesized (CH3NH3)Pb1-xMnxCl3 (or Mn-doped MAPbCl3) crystals by inverse temperature crystallization method to develop scintillator materials and evaluated their photoluminescence (PL) and scintillation properties systematically. The Mn-doped MAPbCl3 crystals showed a sharp emission peak at approximately 410–430 nm with short decay times on the order of nanoseconds and a broad peak at approximately 600 nm with a long decay time on the order of milliseconds in PL and scintillation. Furthermore, pulse height spectra of the Mn-doped MAPbCl3 crystals with a shaping time of 1 µs were measured, and the obtained scintillation light yields were estimated to be 66 (x = 1), 82 (x = 5), and 67 (x = 10) photons/5.5 MeV-α. Moreover, afterglow levels of the Mn-doped MAPbCl3 crystals were found to be 161 (x = 1), 264 (x = 5) and 170 (x = 10) ppm, which were comparable to a previously reported afterglow level of Tl-doped CsI.

Development of self-activated Tl2ZnCl4 and Tl3ZnCl5 scintillators

Abstract We report the photoluminescence and scintillation properties of two new self-activated scintillators, based on Tl2ZnCl4 and Tl3ZnCl5 crystals with large effective atomic numbers (Zeff = 73.2 and 74.6, respectively), for application in X- and gamma-ray detection. The emission bands of the Tl2ZnCl4 and Tl3ZnCl5 crystals were observed at 472 nm. The peak wavelengths were characteristic of self-activated thallium-based chloride crystals. The estimated light yields of the Tl2ZnCl4 and Tl3ZnCl5 crystals were approximately 10,000 and 2100 photons/MeV, respectively. The light yield measured for Tl2ZnCl4 matches that of commercially available scintillators, such as Gd2SiO5(Ce) (10,000 photons/MeV).

Synthesis, experimental and DFT investigations on semiorganic NLO active L-threonine lithium chloride single crystal

Semiorganic single crystals of L-Threonine Lithium Chloride were wealthy developed by slow evaporation method at ambient circumstances. The structure was illuminated by single crystal XRD technique and the structure be owned by orthorhombic system. Density functional theory computations using B3LYP/6-311++ G(d,p) base set gives optimized structural parameters of title compound. The Theoretically identified hyperconjugative molecular interactions are accountable for the stabilization of compound are obtain by NBO analysis. Besides, Mulliken atomic charges and molecular electrostatic potential were also executed.

Optical, spectral and NLO properties of L-Leucine potassium chloride crystals

L-Leucine potassium chloride (LLPC) crystals have been synthesized and grown by cost effective slow evaporation technique in water as a solvent. The single crystal XRD analysis shows that the grown crystal has monoclinic structure and X-ray powder diffraction study indicates the crystalline nature of the compound. The FT-IR spectroscopic studies reveal the various functional groups of the sample. The linear optical properties of the grown LLPC crystals were studied by recording the UV–Vis-NIR spectrum in the range 200–1100 nm. The Second harmonic generation efficiency of the title material was tested using Kurtz and Perry experimental technique which reveals that L-Leucine potassium chloride crystal is the potential candidate for nonlinear optical applications. Third order NLO parameters like nonlinear absorption coefficient, refractive index nonlinear and nonlinear susceptibility of LLPC crystals were analysed by Z-scan method.

The Effect of Ammonium Chloride on the Structure of Hydroxyapatite Nanoparticles and the Proliferative Activity of Mesenchymal Stromal Cells

Synthetic hydroxyapatite nanoparticles that contain ammonium chloride crystals are obtained. The X-ray diffraction, thermogravimetric analysis, and BET methods show that ammonium chloride crystals are decomposed in argon in the temperature range of T = 220–270°C. The heat treatment at T = 300°C gives thermal stability to the nanoparticles. The presence of ammonium chloride in the culture medium has a substantial effect on the biocompatibility of nanoparticles. An increase in its content reduces the proliferative activity of mesenchymal stromal cells.

Scintillating glass‐ceramic substrates for indirect flat panel detectors in digital radiography

AbstractIndirect flat panel detectors (I‐FPDs) enable digital radiography at high X‐ray energies. However, the performance of these devices is limited due to the large number of X rays that pass through them undetected. The authors hypothesize that a glass‐based scintillator may serve as a substrate for the thin film transistors and photodiodes in an I‐FPD, leading to improvements in X‐ray detection for improved performance. The authors synthesized a series of five glass‐ceramic scintillators based on an oxyhalide glass matrix. Each glass ceramic contains barium chloride crystals which serve as scattering centers to prevent “light trapping” in the material; barium chloride is also a well‐known scintillation crystal. Four of the samples contain trivalent terbium, which serves as a second luminescent center. The light output of each sample was compared against a well‐known X‐ray scintillator, gadolinium oxysulfide (GOS) under RQA9 exposure conditions, in the back‐irradiation configuration. The addition of terbium oxide to the glass composition increases the detected light output, which varies by concentration. The thickness of the glass‐ceramic scintillator has a profound effect on performance, with the results influenced by such factors as self‐attenuation of emission in the thicker samples and decreased X‐ray capture in the thinner samples. The brightest sample tested achieved a light output 13% that of the GOS intensifier screen. The results indicate that the use of scintillating glass‐ceramic substrates should lead to increased performance in indirect digital radiography.

Pyrolysis of wood and PVC mixtures: thermal behaviour and kinetic modelling

Wood waste containing halogenated compounds such as polyvinyl chloride (PVC) is in abundant supply, although the pyrolysis of such waste feedstock for energy production may cause corrosion and environmental problems due to the release of HCl gas. Hence, there is a need to understand the pyrolysis behaviour of chlorine-contaminated wood in order to develop methods that minimise the impact of chloride species on pyrolysis equipment and product quality. In literature, few studies exist on the kinetic analysis of wood and PVC co-pyrolysis. The existing models assume a single-step reaction with an n-order reaction mechanism for the entire process, which may lead to large errors in the kinetic parameters estimated. Therefore, in this paper, we develop and validate a multi-step kinetic model that predicts the pyrolysis behaviour and reaction mechanism of poplar wood (PW) pellet with different contents of PVC (0, 1, 5, 10, 100 wt%). Using data from thermogravimetric analysis of the pellets at heating rates of 5, 10 and 20 °C/min, we determined the apparent kinetic parameters by combining Fraser-Suzuki deconvolution, isoconversional methods and master plot procedures. Our model fitted the experimental data well with a deviation of less than 4.5%. Our results show that the addition of 1 wt% PVC to PW decreases the activation energy of hemicellulose and cellulose pyrolysis in PW from 136.3 to 101.6 kJ/mol and from 216.7 to 108.2 kJ/mol, respectively. This demonstrates the importance of acid hydrolysis reactions between the cellulosic fibres of PW and HCl released from PVC dehydrochlorination. Furthermore, we found that a nucleation and growth mechanism best represents the rate-limiting interactions between PVC and PW, which we linked to the formation of metal chloride crystals from acid-base reactions between HCl and PW minerals. Our kinetic model is an improvement of current models for the co-pyrolysis of wood and PVC, and can be readily used in a reactor-scale model of a pyrolyser or gasifier due to its relative simplicity.

Preparing High-Purity Anhydrous ScCl3 Molten Salt Using One-Step Rapid Heating Process

In this study, a one-step rapid heating novel process was used to prepare high-purity anhydrous scandium chloride molten salt with low-purity scandium oxide. High-purity anhydrous ScCl3 molten salt was used as the Sc-bearing raw material for preparing the Sc-bearing master alloy. Inert gas was used to enhance the purity of anhydrous scandium chloride and reduce the hydrolysis rate of scandium. The results show that high-purity scandium chloride (purity, 99.69%) with the scandium content of 29.61%, was obtained, and the hydrolysis rate of scandium was 1.19% under the conditions used: removing ammonium chloride; residual crystal water temperature of 400 °C; m(Sc2O3):m(NH4Cl) = 1:2.5; holding-time of 90 min; heating-rate of 12 °C/min; and argon flow of 7.5 L/min. XRD, SEM, and EPMA analyses further verified that anhydrous scandium chloride crystallization condition was relatively good and the purity of high-purity anhydrous scandium chloride approached the theory purity of anhydrous scandium chloride.

Development of Ce- and Eu-doped TlSr2Cl5 scintillators

Luminescence and scintillation properties of Eu2+- and Ce3+-doped TlSr2Cl5 crystals are reported for large effective atomic number (Zeff = 63.7) that have potential applications in X-ray and gamma ray detection. We have previously developed TlSr2Cl5 crystalline scintillators. To improve the scintillation properties of TlSr2Cl5, Ce3+ and Eu2+ were doped into the crystals in this study. The scintillation emission bands of Eu2+-doped TlSr2Cl5 were observed at 420 nm and those for Ce3+-doped TlSr2Cl5 were observed at 380, 450, and 500 nm. Band peaks at 450 and 500 nm were similar to those of undoped TlSr2Cl5, which are characteristic of self-activated thallium-based chloride crystals. The light yields of Ce3+- and Eu2+-doped TlSr2Cl5 were estimated to be approximately 16,000 and 21,000 photons/MeV, respectively. The light yield of Eu2+-doped TlSr2Cl5 is higher than that of undoped TlSr2Cl5 crystals (19,000 photons/MeV). It was suggested that Eu2+ is more suitable dopant for TlSr2Cl5 than Ce3+. The higher light yield of Eu2+-doped TlSr2Cl5 is due to the emissions by Eu2+ ions, which makes it easier to distinguish peaks from noise and improve the energy resolution.

Experiment and kinetic model study on modified potassium-based CO2 adsorbent

In this paper, aluminium chloride crystal was used as precursor to prepare silica-alumina aerogel support by sol-gel method, and the active component K2CO3 was supported on the aerogel support by incipient-wetness impregnation method to obtain a modified potassium-based adsorbent. CO2 adsorption experiment was performed on the adsorbent under different reaction conditions using a small fixed-bed reactor self designed. Based on the characterization results of low temperature N2 adsorption-desorption experiments and scanning electron microscopy, CO2 adsorption characteristics of modified potassium-based adsorbents were studied. The prepared silica-alumina aerogel support has good microstructure and uniform pores with specific surface area and pore volume are 445.7517 m2/g and 2.3270 cm3/g, respectively, and the mesopores account for more than 99%. After loading, the active component K2CO3 is uniformly dispersed. Through model comparison, it was determined that the shrinking core model and Avrami fractional kinetic model were used to fit the experimental results in order to study the reaction kinetics and adsorption kinetics. The results show that as the temperature rises, the amount of CO2 adsorbed by the adsorbent increases first and then decreases. The increase in temperature can improve the activity of the active site of the adsorbent and make the reversible exothermic reaction occur while the adsorbent adsorbs CO2 cannot proceed in the forward direction at the same time. According to the kinetic analysis, the control period of the surface chemical reaction is too short due to the high temperature, which caused low carbonation conversion. The optimal designed loading of modified potassium-based adsorbent, reaction temperature, water vapor pretreatment time, CO2 concentration and total gas volume were 30%, 60 °C, 30 min, 12.5%, and 500 mL/min, respectively.

Comparison of organic – inorganic nano-compositions created by different deformation – chemical techniques

Comparative studies of compositions from polystyrene and inorganic crystals of cesium sulfate and cesium iodide obtained by different methods gave new experimental facts and versions about particularities of structures and properties of these materials. The methods of creation of these compositions were based on two deformation – chemical techniques: solidification of micro-fibers from solutions of polystyrene with cesium sulfate and cesium iodide particles and introduction of polystyrene as the doping substance into single crystals of cesium iodide and potassium chloride by means of a ball rolling. In both cases micro- and nanosize singularities of the mass transfer were observed during the forming of these compositions. The microfibers formed by solidification of doped solutions of polystyrene turned out to be split to sets of nano – filaments. In the process of the dynamical centrifuging they formed the bundles parallel to the axis of the fiber, whereas the slow pulling of the fibers from the solution with a thin glass stick created saw-like chains of short pieces of the nano-filaments going along the axis of the fiber. These geometries were regulated by the ratios of compressive and tensile internal stresses, the chemical content of the components, lengths of the polystyrene molecules, viscosity of the solution. Superfast and superdeep mass transfer in the form of nano- and micro-filaments observed in our experiments is attributed to the soliton-like propagation provided by non-linear changes of the properties of the matrix in the vicinity of the filament. Hence wide sets of various nanostructures required by new trends of electronics, optics, etc. can be prepared by rather economic techniques.

Real-time observation of dynamic structure of liquid-vapor interface at nanometer resolution in electron irradiated sodium chloride crystals

The dynamics and structure of the liquid and vapor interface has remained elusive for decades due to the lack of an effective tool for directly visualization beyond micrometer resolution. Here, we designed a simple liquid-cell for encapsulating the liquid state of sodium for transmission electron microscopic (TEM) observation. The real-time dynamic structure of the liquid-vapor interface was imaged and videoed by TEM on the sample of electron irradiated sodium chloride (NaCl) crystals, a well-studied sample with low melting temperature and quantum super-shells of clusters. The nanometer resolution images exhibit the fine structures of the capillary waves, composed of first-time observed three zones of structures and features, i.e. flexible nanoscale fibers, nanoparticles/clusters, and a low-pressure area that sucks the nanoparticles from the liquid to the interface. Although the phenomenons were observed based on irradiated NaCl crystals, the similarities of the phenomenons to predictions suggest our real-time ovserved dynamic structure might be useful in validating long-debated theoretical models of the liquid-vapor interface, and enhancing our knowledge in understanding the non-equilibrium thermodynamics of the liquid-vapor interface to benefit future engineering designs in microfluidics.

TlSr2Cl5: New intrinsically activated crystalline scintillator

We report the luminescence and scintillation properties of TlSr2Cl5 crystals, which have a large effective atomic number (Zeff = 63.7), for application in X-ray and gamma ray detection. TlSr2Cl5 crystals were prepared under vacuum using the self-seeding solidification method. The scintillation emission bands were observed at 430 and 490 nm, which are close to the emission wavelengths of TlMgCl3 and TlCdCl3. The peak wavelengths were characteristic of self-activated thallium-based chloride crystals. The scintillation decay time constants were estimated to be 7.5 ns (61%), 99 ns (7%), and 1375 ns (32%). These decay time constants are close to those of TlMgCl3 and TlCdCl3 and are also characteristic of self-activated thallium-based chloride crystals. The light yield of TlSr2Cl5 was estimated to be approximately 19,000 photons/MeV, which is higher than that of Gd2SiO5(Ce) (GSO) (10,000 photons/MeV) and close to that of Lu2SiO5(Ce) (LSO) (27,000 photons/MeV).

Evolving Crystal Morphology of Potassium Chloride Controlled by Optical Trapping

Dynamic morphology evolution of potassium chloride (KCl) crystal was demonstrated by surface optical trapping with a focused continuous-wave near-infrared laser. Optical trapping at an air/solution...

Artificial wetland planted with Limonium Perezzi, for the treatment of wastewater from tanning

The wastewater from leather tanning contains different types of pollutants depending on the internal process that is carried out, in particular, the riparian and tanning stages provide the greatest contaminant load within the process, in terms of organic matter, grease and oils, chlorides, chromium, sulfides among other substances. This study analyzed the efficiency of a biological treatment system, consisting of artificial wetlands of horizontal subsurface flow, in order to evaluate the removal of salinity and organic load present in the water produced during the process of soaking leathers. Two prototypes were tested, one planted with Limonium perezzi and the other unplanted as a control parameter, the wetlands were operated for 32 days. The results show that the planted wetland removes 49.2% of the initial chloride present (44,414.8 mgCl-/L) in the water and 86.2% of the total organic carbon (755.9 mgC/L). It was demonstrated that artificial wetlands are still a viable and efficient alternative in terms of organic load removal, on the other hand, the selected plant showed a very good performance in the treatment of wastewater because of its high tolerance to high concentrations of salt dissolved in the water, reaching perspiration of sodium chloride crystals through the leaves and stem.

The structure of water

Images of water clusters have been reported recently. In this paper, the dynamics of water clusters when dissolving crystals of sodium chloride is studied under a microscope. Images of water clusters have two different colours, a dark outer layer and a shallow inner layer as a water cluster is composed of two phases. Since the experiments were conducted at room temperature there should be no solid phase (ice) in water clusters. Therefore, it is proposed that individual water clusters are composite of two phases, an outer liquid phase and an inner gas phase. Obviously, there will be water clusters everywhere in bulk water and they maintain a certain distance among them; there are spaces among water clusters which are filed with gases and named free volume. At a molecular level, hydrogen atom in a water cluster are pointing outward while oxygen atoms are pointing inward. In this configuration, the cluster is more stable. A formula for calculating the forces inside a water cluster is developed. In this study the structure of water is presented in a new light. The study has opened a door for further understanding of water and its mysterious properties.

Impact of Cellulose Dissolution on 1-Butyl-3-Methylimidazolium Chloride Crystallization Studied by Raman Spectroscopy, Wide-Angle X-ray Scattering, and Solid-State NMR

Ionic liquid 1-butyl-3-methylimidazolium chloride (bmimCl) is a widely applied solvent for cellulose. In this work, we studied the crystallization behavior of bmimCl in the presence of cellulose, a...

Chloride Penetration into Concrete under the Coupling Effects of Internal and External Relative Humidity

Chloride penetration frequently happens in an unsaturated concrete; in this case, the chloride migration is under the coupling effects of internal moisture and external relative humidity (RH). Various chloride attack tests were designed in this paper to investigate the effects of internal moisture and external RH (50–100%) on the chloride penetration into an unsaturated concrete, and the chloride content was determined to quantify the chloride migration in concrete. The results highlighted that there was a good correlation between the chloride penetration into concrete and its internal RH. The chloride ion was difficult to penetrate into concrete when its internal RH was below 50%; however, the chloride penetration rate increased when the internal RH of concrete was above 75%, and the chloride migration increased with increasing RH and exposure duration. Water evaporation in concrete increased with decreasing external RH, and an obvious increase in the surface chloride content may be observed when external RH was 50%; however, when external RH was above 75%, the inner chloride content increased and surface chloride content decreased with increasing exposure duration. Simulating the chloride penetration under wet‐dry cycling, the water migration resulted in an increase in the surface chloride content and a decrease in the inner chloride content, and the chloride crystal precipitated on the surface of concrete with a high w/c ratio.