Laser Monitoring Research Articles

Equilibrium solubility, thermodynamic properties and Hansen solubility parameter of doxifluridine in (±)-2-ethyl-1-hexanol + (methanol, ethanol and acetone) at various temperatures

The solubility values of doxifluridine in three mixed solvents of (±)-2-ethyl-1-hexanol + (methanol, ethanol and acetone) ware determined within 278.15–328.15 K under 0.1 MPa using a laser monitoring technique. It can be seen from the solubility profiles that all the solubility of doxifluridine in the mixed solvents increases with the increasing mass fraction of the co-solvent (methanol, ethanol or acetone) and the experimental temperature. The minimum and maximum mole fraction solubility of doxifluridine was found in ethanol + (±)-2-ethyl-1-hexanol (4.981 × 10−5 at w1 = 0.1003, T = 278.15 K) and methanol + (±)-2-ethyl-1-hexanol (1.109 × 10−1 at w1 = 0.9001, T = 328.15 K), respectively. Through the application of Hansen solubility parameters, the solubility order and miscibility of doxifluridine in the three mixed solvents studied in this work was revealed, and the results showed that the dissolution behavior of doxifluridine was not only determined by a single factor, but also the result of the comprehensive action of various solubility parameters. In addition, three semi-empirical models (λh, Modified Apelblat, and MA) and one activity coefficient model (UNIQUAC) were applied to fit the solubility data of doxifluridine. The minimum average values of ARD (average relative deviation) and 104 RMSD (root-mean square deviation) were acquired from Modified Apelblat model, verifying that Modified Apelblat model provides maximum consistency among the four models. Furthermore, Van't Hoff model was used to calculate the apparent thermodynamic parameters (ΔsolG°, ΔsolH°, ΔsolS°) of the dissolution process of doxifluridine. The results demonstrated that the dissolution process of doxifluridine in all the three mixed solvents studied was an entropy-driven endothermic process.

Determination and correlation solubility of 4-nitroimidazole in twelve pure solvents from 278.15 K to 323.15 K

In this paper, the solubility of 4-nitroimidazole in twelve pure solvents (toluene, benzene, 1,4-dioxane, acetonitrile, ethyl acetate, acetone, GBL, ethanol, methanol, n-butanol, DMF and NMP) were determined by using the laser monitoring system from 278.15 K to 323.15 K under 101.1 kPa, which are 0.00018–0.00070, 0.00021–0.00073, 0.00034–0.00092, 0.00038–0.00142, 0.00047–0.00120, 0.00126–0.00303, 0.00225–0.00517, 0.00310–0.00724, 0.00467–0.00982, 0.00453–0.01940, 0.01947–0.04652, and 0.04670–0.07452, respectively. At constant temperature, the mole fraction solubility of 4-nitroimidazole were increased as the following order: toluene < benzene < 1,4-dioxane < (ethyl acetate or acetonitrile) < acetone < GBL < ethanol < (methanol or n-butanol) < DMF < NMP, and the solubility of 4-nitroimidazole in (ethyl acetate, acetonitrile) and (methanol, n-butanol) had an intersection point at 297.55 K and 281.85 K, respectively. The solubility of 4-nitroimidazole could be increased with increasing temperature in twelve pure solvents. The ideal model, modified Apelblat equation, polynomial empirical equation, and λh equation were used to correlate the experimental values. The experimental solubility values were employed to calculate the standard dissolution enthalpy, standard dissolution entropy and Gibbs energy. The dissolution of 4-nitroimidazole could be an endothermic process in twelve pure solvents. The determination and fitting solubility of 4-nitroimidazole have important guiding significance for the purification and crystallization of its preparation process.

Solubility, Hansen solubility parameter and thermodynamic properties of etodolac in twelve organic pure solvents at different temperatures

In this article, the solubility of etodolac in n-propanol, n-butanol, isopropanol, isobutanol, methyl acetate, n-butyl acetate, n-amyl acetate, isobutyl acetate, isoamyl acetate, toluene, acetone at 278.15 K–323.15 K and dichloromethane at 278.15 K–303.15 K under the pressure of 0.1 MPa was studied using a laser monitoring technology. The experimental results show that the solubility of etodolac in all the 12 pure solvents is positively correlated with the temperature. The van't Hoff model, Apelblat model, λh model, NRTL model and UNIQUAC model were used to fit the etodolac solubility data. Through comparison, it was found that the Apelblat model has the smallest average values of ARD (average relative deviation) and RMSD (root-mean square deviation), and the average values of ARD% and 104 RMSD were 0.92% and 5.99, respectively. The result shows that the Apelblat model was more suitable for correlating the solubility data. The order of solubility of etodolac was analyzed by using Hansen solubility parameter, and the solvent effect was studied by calculating the KAT-LSER parameter. Besides, the thermodynamic properties of the solution process of etodolac were calculated and analyzed by the van't Hoff analysis. The results show that the dissolution process of etodolac is endothermic and entropy-driven.

Measurement and correlation of the solubility of 1-methyl-3,4,5-trinitropyrazole in twelve pure solvents at temperatures from 283.15 K to 323.15 K

In the present study, the solubility of 1-methyl-3,4,5-trinitropyrazole (MTNP) was determined by a dynamic laser monitoring at T = (283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15 and 323.15) K in twelve pure solvents, including water, benzene (Ph), dimethyl sulfate (DMS), methylbenzene (PhMe), tetrahydrofuran (THF), methanol (MeOH), ethanol (EtOH), 1,2-dichloroethane (DCE), nitromethane (NM), acetonitrile (ACN), ethyl acetate (EA) and formic acid (FA), at atmospheric pressure (P = 0.1 MPa). In the temperature range from 283.15 K to 323.15 K, the mole fraction solubility values of MTNP in water, Ph, DMS, PhMe, THF, MeOH, EtOH, DCE, NM, ACN, EA and FA were 0.000008–0.000072, 0.003495–0.025271, 0.002153–0.037197, 0.001602–0.012304, 0.002103–0.074525, 0.000318–0.001625, 0.003752–0.048205, 0.017836–0.047105, 0.008408–0.016783, 0.003579–0.012367, 0.004460–0.022006 and 0.220917–0.443206. As revealed from the experimental results, the solubility of MTNP in twelve pure solvents increased with the increase in the temperature. The solubility behaviors of MTNP in investigated solvents were analyzed with the Hansen solubility parameter (δd, δp, δh, δt, δv and Δδt). The Kamlet-Taft parameters were calculated to delve into the solvent effect. Subsequently, the measured solubility data was correlated with five thermodynamic models, i.e., the modified Apelblat equation, λh equation, NRTL model, Wilson model and Two-Suffix Margules model. Overall, the NRTL model provided the most satisfactory fitting results. As revealed from the results, the minimum average values of relative mean deviation (102ARD) and root-mean square deviation (104RMSD) were determined with the NRTL model that achieved the values of 2.06 and 1.49. Furthermore, the dissolution thermodynamic parameters, including mixing enthalpy (ΔmixH), mixing entropy (ΔmixS) and mixing Gibbs energy (ΔmixG) were calculated according to the Wilson model, and the relative contributions of enthalpy %ζH and entropy %ζS were also calculated. It can be seen that the dissolution of MTNP in a given solvent is spontaneous and entropy driven.

Thermodynamic modelling, Hansen solubility parameter and solvent effect of oxaprozin in thirteen pure solvents at different temperatures

The solubility of oxaprozin in thirteen organic solvents (methanol (MeOH), ethanol (EtOH), n-propanol (n-PrOH), n-butanol (n-BuOH), n-pentanol (n-PeOH), methyl acetate (MeAC), ethyl acetate (EtAC), n-propyl acetate (n-PrAC), n-butyl acetate (n-BuAC), n-amyl acetate (n-AmAC), N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO)) was determined using a laser monitoring method at atmospheric pressure in this work. The measured temperature range for all selected solvents is 278.15 K to 323.15 K except DMSO 293.15 K to 323.15 K. Through the entire studied temperature range, the results turned out that oxaprozin solubility in selected solvents has a positive correlation with temperature variation. Four mathematical models were employed to correlate the solubility data including two empirical models (modified Apelblat model, λh model) and two activity coefficient models (UNIQUAC model, NRTL model), with the modified Apelblat model giving the best regression. Solubility order of oxaprozin in thirteen solvents was analysed by using the Hansen solubility parameter (HSP) and the solvent effect (solvent interaction) was investigated through correlating oxaprozin solubility in selected solvents based on KAT-LSER model. Moreover, according to van’t Hoff equation, thermodynamic properties including apparent standard molar enthalpy change (ΔsolH °), apparent standard molar Gibbs energy change (ΔsolG°) and apparent standard molar entropy change (ΔsolS) of the dissolution process of oxaprozin were also calculated and discussed.

System of Laser Monitoring of Water Pollution with Application of Relative Description of Signal Shape

As a rule, the wastewater treatment system is not designed to filter substances formed, as a result of beyond design basis accident. The nature of the beyond design basis accident is associated with the shortterm appearance of a clot of these substances in wastewater, determined by the volume of the substance storage tank. Therefore, a rational approach is to divert this portion of the formed substances into a separate branch of the sewage system or sedimentation tanks. The aim of the work is to implement this approach by creating a laser monitoring system for water pollution.The article proposes a system for automatic detection of a clot of emergency discharge of pollutants into the wastewater of an industrial enterprise. The structural diagram of the system and the purpose of its main elements are given. The system should provide clot detection in real time. To ensure this function, a preliminary study is made of the spectral characteristics of all substances that may appear in wastewater in the event of an emergency.Based on these data, the wavelengths of laser radiation in the system are selected. The obtained measurement data from several probes are presented in the form of a lattice function, which is translated into a relative description representing the order relationship matrix on the set of lattice function components. The relative description is invariant to linear changes in the lattice function. The decision to detect any substance from emergency discharges is made based on a comparison of the relative description of the measurements with the standards prepared at the stage of system setup.The article provides an example of the formation of standards for emergency clots from glycerin and allyl alcohol. The graphs of the lattice functions obtained from the IR spectra of emergency discharges of these substances are given; algorithms for constructing a lattice function and comparison of lattice functions. Thus, using the developed mathematical description of the shape of digital signals based on the relative description, the signal of the monitoring curve can be described in the form of a curve of the optical density change of an aqueous medium.

Analysis of surface changes of burning nanopowders using digital processing of laser monitor images

An imaging laser projection system, a laser monitor, is applied for real-time monitoring of the surface of nanopowders during high-temperature combustion. The mirror-based scheme of the laser monitor is used in the experiments to increase the range of observation. For the analysis of surface changes during combustion, the correlation coefficient together with average brightness of the images of laser monitor obtained by digital processing are proposed to use. The results of calculating the correlation coefficient demonstrate compliance with the change in the intensity of the images of the laser monitor during the combustion and visual observation of the combustion process. The distortions introduced by the instability of the brightness amplifier into the measurement results are estimated. When observing a static test object, the variation of correlation coefficient is three orders of magnitude less than fluctuation in the correlation coefficient during combustion, the variation of average image brightness is less than 5%. The obtained results indicate the possibility of the usage of the correlation coefficient and average brightness of the images as informative parameters in the analysis of surface changes of burning nanopowders in studies using laser monitors with both conventional and mirror-based schemes.

An Optical System with Brightness Amplification for Studying the Surface of Metal Nanopowders during Combustion

The results of using an optical system with brightness amplification based on copper bromide vapors, which consisted of a laser monitor for studying the surface of an aluminum nanopowder during a high-temperature combustion process, are presented. A pulsed laser with a wavelength of 660 nm and the possibility of external synchronization was used to initiate the combustion process, thus making it possible to set the start time and the duration of the exposure. The average brightness of images of the brightness amplifier obtained by registering the output radiation with a photodiode is used to quantify the change in the reflection coefficient of the nanopowder surface and the time stages of the combustion process. The conventional scheme of a laser monitor with a focal length of 8 cm and a scheme with an increased focal length of 50 cm are considered. The possibility to perform quantitative analysis of processes during research using a laser monitor is shown. The error introduced to the measurement results by the instability of the lasing energy of the brightness amplifier is estimated. When observing the surface of the aluminum plate used as an object of research, the fluctuation in the average brightness of the laser-monitor images that was recorded with the photodiode did not exceed 5%.

Piperonylonitrile solubility in thirteen pure solvents: Determination, Correlation, Hansen solubility parameter, solvent effect and thermodynamic analysis

This work was to investigate piperonylonitrile in terms of its solid–liquid equilibrium solubility in thirteen pure solvents by employing laser monitoring technique. Solubility measurements were completed in range of temperature at (288.15–323.15) K in 1,4-dioxane and at (278.15–323.15) K in isopropanol, 2-methoxyethanol, ethanol, ethyl acetate, methanol, n-propanol, n-propyl acetate, N,N-dimethylformamide (DMF), isopropyl acetate, methyl acetate, acetone as well as acetonitrile under 0.1 MPa. The holistic solubility profile showed that piperonylonitrile solubility in all measured solvents was proportional to the increasing of test temperature. It was also found that the mole-fraction solubility values of piperonylonitrile in measured solvents at 298.15 K exhibited a sequence of: DMF (0.2636) > 1,4-dioxane (0.2212) > methyl acetate (0.1838) > acetone (0.1813) > ethyl acetate (0.1657) > n-propyl acetate (0.1486) > acetonitrile (0.1435) > isopropyl acetate (0.1295) > 2-methoxyethanol (0.1010) > methanol (0.01915) > ethanol (0.01664) > n-propanol (0.01594) > isopropanol (0.01268). The miscibility and solubility order of piperonylonitrile were further revealed by the means of Hansen solubility parameter, demonstrating that solubility behaviors could be well explained by the comprehensive action of various solubility parameters. Besides, the influence on the piperonylonitrile solubility of solute–solvent interaction and solvent–solvent interaction was illustrated via the KAT-LSER model. It was figured out that hydrogen bonding acidity and hydrogen bonding basicity exerted unfavorable influence on piperonylonitrile solubility. Moreover, the measured piperonylonitrile solubility was fitted with Wilson, NRTL, UNIQUAC, Two-Suffix Margules and NRTL-SAC model, and correlation of experimental results with the use of five activity coefficient models showed that sufficient agreement with the calculated data. Finally, the thermodynamic quantities (ΔmixH, ΔmixG and ΔmixS) of the mixing process in different solvents were computed based on measured solubility values and UNIQUAC model. The results demonstrated that the mixing process was entropy-driven and spontaneous.

Equilibrium solubility of exo-5,6-dehydronorcantharidin in thirteen pure solvents: Determination, correlation, Hansen solubility parameter and thermodynamic properties

This research was focusing on determining the solid-liquid equilibrium solubility of exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic acid anhydride (exo-5,6-dehydronorcantharidin) in thirteen mono-solvents by using laser monitoring approach at diverse temperature and pressure “p = 0.1 MPa”. The results showed that the solubility data of exo-5,6-dehydronorcantharidin in all solvents was positively correlated with experimental temperature. Besides, the mole-fraction solubility values of exo-5,6-dehydronorcantharidin in all considered solvents at “T = 298.15 K” were found maximum in N-methyl-2-pyrrolidinone (0.184) followed by N,N-Dimethylformamide (0.150), acetone (0.0629), acetonitrile (0.0508), methyl acetate (0.0420), 1,4-dioxane (0.0342), ethyl acetate (0.0275), n-propyl acetate (0.0210), isopropyl acetate (0.0191), butyl acetate (0.0172), isobutyl acetate (0.0165), amyl acetate (0.0137) and isoamyl acetate (0.0129). The polarity and Hansen solubility parameter of studied solvents were employed to reveal the affinity and solubility order of exo-5,6-dehydronorcantharidin, and the results indicated that the miscibility between solute and solvent relied on comprehensive effects of multiple factors. Moreover, the obtained solubility data was correlated with Wilson, NRTL, UNIQUAC and NRTL-SAC model. The correlation results showed that the UNIQUAC model can provide the best fitting effect with lower values of average relative deviation (ARD) and root-mean square deviation (RMSD). Finally, thermodynamic mixing and dissolution properties of exo-5,6-dehydronorcantharidin in thirteen neat solvents were calculated based on UNIQUAC model as well as experimental values.

Learning Ratio Mask with Cascaded Deep Neural Networks for Echo Cancellation in Laser Monitoring Signals

Laser monitoring has received more and more attention in many application fields thanks to its essential advantages. The analysis shows that the target speech in the laser monitoring signals is often interfered by the echoes, resulting in a decline in speech intelligibility and quality, which in turn affects the identification of useful information. The cancellation of echoes in laser monitoring signals is not a trivial task. In this article, we formulate it as a simple but effective additive echo noise model and propose a cascade deep neural networks (C-DNNs) as the mapping function from the acoustic feature of noisy speech to the ratio mask of clean signal. To validate the feasibility and effectiveness of the proposed method, we investigated the effect of echo intensity, echo delay, and training target on the performance. We also compared the proposed C-DNNs to some traditional and newly emerging DNN-based supervised learning methods. Extensive experiments demonstrated the proposed method can greatly improve the speech intelligibility and speech quality of the echo-cancelled signals and outperform the comparison methods.

Imaging system with brightness amplification for a metal-nanopowder-combustion study

This work discusses an optical system with brightness amplification—a laser monitor, as well as the system's application for real-time imaging of the surface of metal nanopowders during high-temperature combustion. The advantage of the laser monitor is its combination of microscopic magnification, laser backlighting, and narrow-band filtering, which, together with high-speed video recording, makes it possible to visualize the nanopowder surface through the intense background lighting produced by a high-temperature burning sample. We used two laser-monitor schemes with short and long focal lengths to study the dynamics of the combustion process at different spatial resolutions. For compounds whose combustion is accompanied by intense scattering of the combustion products, we recommend using the laser monitor with increased monitoring distance via a mirror-imaging scheme. This proposed technique allows real-time monitoring of the high-temperature-combustion processes accompanied by intensive lighting and product scattering at a distance of 50 cm from the optical system. Both systems allow quantitative characterization of the combustion process by registering the average output of the brightness amplifier together with the overall brightness of glowing. The combustion of nanoAl + nanoFe and nanoAl + nanoFe + microAl powder mixtures was visualized using a laser monitor for the first time and compared with the combustion of aluminum nanopowder without additives.

Solubility measurement, model evaluation and molecular simulations of (R)-(-)-phenylephrine hydrochloride in three binary solvents

In this research work, laser monitoring method was employed to investigate the mole-fraction solubility data of α adrenergic receptor agonists (R)-(-)-phenylephrine hydrochloride (R-PEHC) in three binary solvents namely “methanol (MtOH) + ethanol (EtOH), MtOH + isopropanol (IPOH) and EtOH + IPOH” over the temperature of (278.15–323.15) K with temperature range of 5 K under 0.1 MPa. The results demonstrated that experimental solubility was positively related with temperature while inversely associated with mass fraction of anti-solvents. At the same temperature and mass fraction of anti-solvent, the general solubility order of R-PEHC in binary solvents was MtOH + EtOH > MtOH + IPOH > EtOH + IPOH. Meanwhile, Hansen solubility parameter (HSP) was employed to investigate the solubility order, and the results showed solubility behavior could be analyzed well by selected four solubility parameters (Δδp, Δδh, Δδt and Δδ). Besides, the molecular simulation technology was conducted to investigate solvation free energy (Esol) between R-PEHC and selected solvents. The results showed that experimental solubility differences in various solvents were attributed to the differences in solvation free energy. Moreover, mathcad software (Version: 15) was applied to correlate experimental solubility with respect of temperatures by using five thermodynamic models (UNIQUAC, Wilson, Three-Suffix Margules, Jouyban-Acree-modified Apelblat (J-A-A) and NRTL model). All selected models provided satisfactory goodness-of-fit with R-PEHC solubility data. Furthermore, apparent thermodynamic properties of solutions were calculated based on van’t Hoff equation as well as experimental solubility, the results indicated that dissolution process was always endothermic and entropy-driven.

Neurosurgical management of conus lipoma in Canada: a multi-center survey.

Lipomyelomeningocele (LMM) is a congenital spinal cord anomaly. While patients with LMM may initially be asymptomatic, neurological sequelae secondary to LMM may become apparent as the patient ages. Consequently, some pediatric neurosurgeons have advocated for upfront neurosurgical interventions irrespective of the presence of symptoms at diagnosis. By contrast, others pursue a conservative approach when overt neurological symptoms are not yet evident. In light of the various practice styles to the heterogeneous anatomical locations, symptoms, and ages associated with LMM, we have conducted a multi-center survey of Canadian pediatric neurosurgeons using clinical vignettes representative of LMM patients. An online survey of the opinions of Canadian pediatric neurosurgeons was conducted using 5 separate cases with magnetic resonance imaging (MRI) scans of the lumbar spine. Each case was accompanied with the same three clinical vignettes, which varied in severity at time of presentation: asymptomatic, progressive somatic motor deficit, or longstanding overflow incontinence. Participants were asked the question, "Would you offer surgical management?" after each clinical vignette. After the five cases and their corresponding 3 clinical vignettes, participants were asked, "If you answered yes to any of the preceding questions, what type of surgery would you perform?". Options for surgical goals and techniques included complete removal, near-total removal, debulking, detethering, and expansile duroplasty. Surgical adjuncts included CUSA, LASER, and neurophysiologic monitoring. Twenty-three responses were received from the 38 questionnaires sent out to all staff pediatric neurosurgeons across academic medical centers in Canada. This represented a response rate of 61%. Canadian pediatric neurosurgeons generally maintain a conservative approach to the surgical management of LMM as only 13% (n= 3) of surgeons indicated that they would operate in all scenarios. By contrast, 43% (n= 10) indicated surgical management in only those cases presenting with symptoms, and another 43% (n = 10) displayed a variable surgical approach. Nine percent (n= 2) of participants would not perform surgery for incontinence. The greatest level of disagreement among participants pertained to the management of asymptomatic sacral LMM where 43% of participants favored prophylactic surgery, while 57% of participants preferred conservative management. The current study highlights the differences in management of LMM among Canadian pediatric neurosurgeons and provides further support for future prospective cohort studies to develop appropriate expert opinions and guidelines such that the care of LMM patients may be according to evidence-based best practice. This is especially true for the treatment of asymptomatic patients, a patient group that would benefit from a randomized controlled trial to assess the long-term outcomes of conservative and surgical management.

Prediction and fitting of weld morphology of Al alloy-CFRP welding-rivet hybrid bonding joint based on GA-BP neural network

Abstract In the riveting-welding hybrid bonding of aluminum alloy and the Carbon Fiber Reinforced Polymer (CFRP), the welding joint morphology was one of the most important factors for the welding property. In the hybrid bonding process, laser-induced tungsten inert gas hybrid welding technology was used as the welding source, which had a plurality of parameters, such as laser power, arc current, defocused distance and welding speed and etc. The variation of each parameter could directly influence the welding properties. The prediction model of the laser power, welding current, defocused distance and welding speed on the profile of the welding joint morphology was established by using the BP neural network optimized through the genetic algorithm (GA-BP). The contour data of the welding joint was acquired by establishing the polar coordinate system. The geometric morphology of the welding joint was ideally fitted by using the cubic interpolation fitting in MATLAB. The results showed that the fitting line was close to the actual profile of the welding joint, and the prediction accuracy of the GA-BP was favorable. The mean absolute percentage error (MAPE) of each group of data did not exceed 3% while the standard deviation (STD) of that was less than 0.1. The study provided a new method to grope for energy transfer and real-time monitoring of laser induced TIG hybrid welding quality.

Experimental study and thermodynamic modeling of a novel heat-resistant explosive in different mono solvents

In this paper, the solubility of 5,5′-bis(2,4,6-trinitrophenyl)-2,2′-bis(1,3,4-oxadiazole) (TKX-55) was first determined by a dynamic laser monitoring at T = (293.15, 298.15, 303.15, 308.15, 313.15, 318.15, 323.15, 328.15 and 333.15) K in fourteen pure solvents, including nitrobenzene (NB), methylethylketone (MEK), dimethyl carbonate (DMC), N,N-dimethylformamide (DMF), methoxybenzene (MOB), ethenyl acetate (VAC), 1,2-propanediol (PDO), cyclohexanone (CYC), epichlorohydrin (ECH), 1-butanol (NBA), n-butyl acrylate (BA), dimethyl sulfoxide (DMSO), tributyl phosphate (TBP) and 2-butanol (IBA), under atmospheric pressure (P = 0.1 MPa). Besides, supersolubility as well as the metastable zone width of TKX-55 in PDO, BA, DMSO and IBA was determined by the dynamic laser monitoring method. The experimental results showed that the solubility of TKX-55 in fourteen pure solvents increases with increasing temperature and the metastable zone width decreases with increasing temperature. The metastable zone width is approximately 2.49 K–43.26 K. In addition, in order to improve the applicability of the solubility, the modified Apelblat equation, λh equation, the polynomial empirical equation, van't Hoff equation and NRTL equation were used to correlate the solubility data of TKX-55, and the results showed that all models can give a satisfactory correlation. The average root-mean-square deviation (102RMSD) values were 1.71, 8.91, 2.33, 6.12 and 3.30, respectively. Moreover, Hansen solubility parameter was used for explaining the solubility order of TKX-55 in selected solvents, the consequences showed that solubility order of TKX-55 resulted from the comprehensive function of several solubility parameters. The solubility parameter of Δδt between TKX-55 and solvents reached from 1.27 MPa0.5 to 15.28 MPa0.5. Furthermore, three kinds of thermodynamic properties of the mixing enthalpy (ΔmixH), the mixing entropy (ΔmixS) and the mixing Gibbs energy (ΔmixG) of TKX-55 in selected solvents were calculated by NRTL equation and the results turned out that the dissolution process was spontaneous. Besides, thermal properties of TKX-55 were measured by differential scanning calorimetry (DSC). The results showed that the melting temperature and the fusion enthalpy were 640.65 K and 19.60 kJ·mol−1, respectively. Finally, solubility values and thermodynamic relations of TKX-55 in fourteen pure solvents would be invoked as fundamental data and models regarding the purification process.

Intervisibility calculation model of monitoring hole and optimization of device installation position

Aiming at the laser monitoring of the strain of the underground pile foundation of buildings, this paper establishes the intervisibility calculation model of a single monitoring hole, and optimizes the installation position of the monitoring device. The results show that the calculation results of the model are basically consistent with the measured data, which solves the problem of repeatedly adjusting the laser when measuring the maximum intervisibility in the past. Finally, the sum of the maximum intervisibility of all monitoring holes is significantly increased by optimizing the installation position.

Solid-liquid phase equilibrium of phenylphosphonic acid in three binary solvents: Determination, correlation and molecular simulation

Abstract In this research work, solubility of pyrethroid insecticide phenylphosphonic acid (PPOA) in three binary solvents including methanol (MtOH) + ethyl acetate (EtAC), ethanol (EtOH) + EtAC at (278.15 to 323.15) K and 1,4-dioxane + EtAC at (288.15 to 323.15) K was investigated by laser monitoring method at 0.1 MPa. Solubility of PPOA increased with the increasing temperature while decreased with the increasing mass-fraction of EtAC. The solubility behavior was studied by molecular simulation. The solute-solvent interaction (Einter) suggested that solubility of PPOA increased with values of Einter increasing and there existed the strong interactions between PPOA and most selected binary solvents except 1,4-dioxane + EtAC. The radial distribution function (RDF) between two components of mixed solvent indicated that the tendency to aggregation of two components molecules increased with the increment of corresponding mole fraction of binary solvents. It also confirmed to some extent that the solute – solvent interaction energy would be weaken and the PPOA solubility in binary selected decreased. At the same time, it was found that the hydrogen bond existed in binary solvents namely “MtOH + EtAC and EtOH + EtAC”. So solubility of PPOA resulted from the integrated effect of solute – solvent and solvent – solvent interactions. Moreover, experimental solubility values were correlated by four multi-component activity coefficient models including Wilson, NRTL, Margules and UNIQUAC model. Four thermodynamic functions provided good correlations with solubility values. Furthermore, thermodynamic properties of mixing process were calculated by Wilson equation and corresponding solubility data. Mixing process was entropy-driven in selected solvents and exothermic in most binary solvents except EtAC and 1,4-dioxane (w1 = 0.2016) + EtAC.

In situ laser reflectivity to monitor and control the nucleation and growth of atomically thin 2D materials*

The growth of atomically thin two-dimensional (2D) layered and other quantum materials is typically performed without in situ monitoring or control. Here, a simple laser reflectivity approach is demonstrated to provide in situ control over sub-monolayer thickness and growth kinetics during pulsed laser deposition (PLD) of MoSe2 layers. First, the general technique is presented with emphasis on designing the maximum sensitivity of the optical contrast through consideration of Fresnel’s equations with proper choice of layer thickness, substrate, and laser monitoring wavelength, incidence angle, and laser polarization. Then the 632.8 nm optical reflectivity of MoSe2 layers on SiO2/Si substrates was predicted and compared with in situ monitoring of MoSe2 growth by PLD under actual growth conditions using a probe HeNe laser beam. The measurements showed high sensitivity and excellent agreement with MoSe2 surface coverages calculated from atomic resolution STEM analysis of 2D layers deposited in arrested growth experiments. Growth kinetics revealed by these measurements showed sigmoidal nucleation and growth stages in the formation of the 2D MoSe2 layers that are described by a simple model, indicating the promise of the laser reflectivity technique for in situ monitoring and control of 2D materials deposition.

Equilibrium solubility, thermodynamic properties and Hansen solubility parameter of N-hydroxy-5-norbornene-2,3-dicarboximide in ethyl acetate + (2-methoxyethanol, methanol and 1,4-dioxane) at various temperatures

Solubility of N -hydroxy-5-norbornene-2,3-dicarboximide (HONB) in three mixed solvents of ethyl acetate + (2-methoxyethanol, methanol and 1,4-dioxane) was investigated within 278.15 K–323.15 K under 0.1 MPa. The solubility profiles indicated that the HONB solubility in measured solvents was proportional to the increment of test temperature and mass fraction of positive solvent (2-methoxyethanol, methanol or 1,4-dioxane). The mole fraction solubility of HONB varied significantly from 0.0115 in ethyl acetate + 1,4-dioxane ( w 1 = 0.2066, 278.15 K) to 0.1788 in ethyl acetate + 2-methoxyethanol ( w 1 = 0.7993, 323.15 K). Hansen solubility parameter was applied to reveal the miscibility and solubility order of HONB in mixed solvents, and the consequences indicated that solubility behaviors of HONB were the result of various solubility parameters comprehensive action. The measured HONB solubility employing laser monitoring technique was correlated with four activity coefficient models (Three-Suffix Margules, NRTL, UNIQUAC and Wilson) in combination with a semi-empirical model (Modified Apelblat). The smallest average values of average relative deviation (ARD) and root-mean square deviation (10 4 RMSD) were obtained from Wilson (0.66%) and Modified Apelblat model (6.02), verifying that these two models provided more satisfactory agreement and correlation than other three models. Furthermore, the thermodynamic parameters (Δ mix H , Δ mix G and Δ mix S ) of the mixing process in different solvents were computed based on measured solubility values and equation parameters of Wilson model. The results demonstrated that the mixing process was entropy-driven and spontaneous. These solubility data and thermodynamic parameters could not merely extend database of HONB, but provide basic guidance for optimizing crystallization and purification process. • Solubility of HONB in three binary solvents was measured. • The miscibility and solubility order of HONB were revealed well by Hansen solubility parameter. • Thermodynamic modeling was realized by using the Margules, NRTL, UNIQUAC, Wilson and Modified Apelblat model. • Thermodynamic properties of mixing process were evaluated by Wilson model.