Deviation Of Density Research Articles

Performance of sorption thermal energy storage in zeolite bed reactors: Analytical solution and experiment

Sorption thermal energy storage (STES) has the advantage of high energy storage density and low heat loss, which has been considered as one of the promising solutions to achieve carbon neutrality in buildings. An insight into the thermal energy storage performance of reactors enables the optimization of STES systems. In addition, the analytical solution is concise and understandable in physical significance. In the present work, the perturbation theory was introduced to derive the analytical solutions for the fluid and solid temperatures in the reactor during the discharging process. Subsequently, a zeolite 13X STES system was built to conduct charging and discharging experiments. Based on the derived analytical solution, the fluid temperature at different axial positions in the reactor and energy storage density (ED) of zeolite were calculated and compared with the measured data. The results showed that there was a good agreement between the experimental test and the analytical solution, in which the maximum deviation of the energy storage density was less than 4 %. The analytical solution could obtain specific functional expressions for STES performance parameter of ED and further receive the results quickly.

Predictive performance for prognosis of aneurysmal subarachnoid hemorrhage with ventricular hemorrhage by imaging combined with clinical and laboratory quantitative index model

Objective: To explore the predictive performance of image quantitative index model, clinical-laboratory index model and image-clinical multi-dimensional fusion model in predicting the prognosis of patients with aneurysmal subarachnoid hemorrhage (aSAH) with intraventricular hemorrhage (IVH). Methods: A total of 349 patients with aSAH and IVH, including 122 males and 227 females, aged 22 to 85 (59±11) years underwent CT scan in the General Hospital of Eastern Theater Command from January 2010 to December 2019 were used as dataset 1 to construct a prognostic model. A prognostic model was constructed for data set 1, and the functional recovery of patients 12 months after discharge was evaluated using the modified Rankin Scale (mRS). According to the results, those patients were divided into two groups: good outcome group (n=267) and poor outcome group (n=82). In addition, 63 aSAH patients with IVH, including 27 males and 36 females, aged 32 to 87 (61±12) years who were admitted to the General Hospital of Eastern Theater Command from January 2020 to December 2021 were collected as dataset 2 for independent verification of the model, including 30 patients with poor prognosis. Clinical information (age and gender), laboratory indicators (blood routine and blood biochemistry), and imaging quantitative indicators (such as volume, density, shape of each ventricle hemorrhage area outlined and extracted on head CT scan etc.) were recorded for all patients (dataset 1 and 2). The clinical, laboratory and imaging quantitative indicators of dataset 1 were screened by using L1 regularization and multiple logistic regression method was used to construct the clinical-laboratory index model, image quantitative index model and image-clinical multi-dimensional fusion model, according to the weight coefficient of features in the clinical-laboratory index model and image quantitative index model, screen out the main features. The model was trained and internally validated by 5-fold cross-validation. The model was validated independently in dataset 2. Results: The AUC (area under the ROC curve) of clinical-laboratory index model, image quantitative index model and multidimensional fusion model constructed based on dataset 1 were 0.75 (95%CI: 0.69-0.81), 0.68 (95%CI: 0.61-0.74) and 0.86 (95%CI: 0.82-0.91). The Delong test showed that there were statistically significant differences between the performance of the multi-dimensional fusion model and the clinical-laboratory index model or image quantitative index model (all P<0.05). The AUC of clinical-laboratory index model, image quantitative index model and multidimensional fusion model of dataset 2 were 0.79 (95%CI: 0.68-0.91), 0.70 (95%CI: 0.57-0.83) and 0.81 (95%CI: 0.70-0.92). In addition, in the clinical-laboratory index model and imaging quantitative index model constructed based on data 1, age, Hunt-Hess grade on admission, Neutrophil/Lymphocyte (N/L) (the weight coefficients in the clinical-laboratory index model were 1.00, -0.59 and 0.44) and the standard deviation of third ventricle hemorrhage density, minimum hemorrhage density of the fourth ventricle, and left ventricle hemorrhage sphericity (the weight coefficients in the image quantitative index model were -1.00, 0.85 and -0.84) were the main features of the screening. Conclusions: Quantitative imaging indicators of ventricular hemorrhage (standard deviation of third ventricular hemorrhage density, minimum density of fourth ventricular hemorrhage, and left ventricular sphericity) are helpful to predict the poor prognosis of patients with aSAH with ventricular hemorrhage. Dimensional fusion model has greater value in predicting poor prognosis of patients.

MAX-DOAS Measurements of Tropospheric NO2 and HCHO Vertical Profiles at the Longfengshan Regional Background Station in Northeastern China

The vertical profiles of nitrogen dioxide (NO2) and formaldehyde (HCHO) in the troposphere at the Longfengshan (LFS) regional atmospheric background station (127°36' E, 44°44' N, 330.5 m above sea level) from 24 October 2020 to 13 October 2021 were retrieved from solar scattering spectra by multi-axis differential optical absorption spectroscopy (MAX-DOAS). We analyzed the temporal variations of NO2 and HCHO as well as the sensitivity of ozone (O3) production to the concentration ratio of HCHO to NO2. The largest NO2 volume mixing ratios (VMRs) occur in the near-surface layer for each month, with high values concentrated in the morning and evening. HCHO has an elevated layer around the altitude of 1.4 km consistently. The means ± standard deviations of vertical column densities (VCDs) and near-surface VMRs were 4.69 ± 3.72 ×1015 molecule·cm-2 and 1.22 ± 1.09 ppb for NO2, and they were 1.19 ± 8.35 × 1016 molecule·cm-2 and 2.41 ± 3.26 ppb for HCHO. The VCDs and near-surface VMRs for NO2 were high in the cold months and low in the warm months, while HCHO presented the opposite. The larger near-surface NO2 VMRs appeared in the condition associated with lower temperature and higher humidity, but this relationship was not found between HCHO and temperature. We also found the O3 production at the Longfengshan station was mainly in the NOx-limited regime. This is the first study presenting the vertical distributions of NO2 and HCHO in the regional background atmosphere of northeastern China, which are significant to enhancing the understanding of background atmospheric chemistry and regional ozone pollution processes.

Grading of Hepatic Steatosis by Ultrasound Quantification

Purpose: Fatty liver is the most common chronic liver disease, and finding the appropriate method for detecting the problem is necessary. The current study aimed to quantity liver steatosis using Computed Tomography (CT), ultrasound images, and Alanine Aminotransferase (ALT) blood test.&#x0D; Materials and Methods: In this work, 163 Non-Alcoholic Fatty Liver Disease (NAFLD) patients implemented CT and ultrasound images on their abdomen regions. The liver and spleen density were calculated using CT images (as the standard method), and then the patients were divided into mild, and moderate to severe groups. During the sonography, an M-value histogram of the liver and the right kidney was drawn and their ratio (liver/kidney) was considered as a Hepatorenal Index (HRI). Mann-Whitney test was used to evaluate the relationships between HRI and ALT values.&#x0D; Results: The mean and standard deviation of the liver density in CT scans were obtained as 51 ± 4 HU. The HRI had better performance (Area Under the Curve, AUC: 0.94) than the ALT (AUC: 0.88) in determining liver steatosis. In addition, there was a significant difference between the mild, and moderate to severe groups (P &lt; 0.001) in HRI and ALT values.&#x0D; Conclusion: Based on the results, HRI is an excellent factor to distinguish between mild, and moderate to severe fatty liver. Notably, HRI is reproducible and operator-independent.&#x0D;

The Microstructural Degradation of Ni-Based Superalloys with Segregation under the Super-Gravity Condition

The Ni-based superalloy is used as the turbine blade, which is subject to the coupling effect of temperature and super-gravity during service. As the Ni-based superalloys are difficult to become homogenous after using the solid solution heat treatment, a study on morphology and composition distribution of Ni-base superalloys with segregation during microstructural degradation is necessary. This study investigates the microstructure of the ex-service turbine blade and cast samples subjected to the high-temperature centrifugal test. The difference in the size and shape factor of the γ′ phase decreased with the stress caused by the super-gravity condition, indicating a higher magnitude of homogenization degree. The higher stress will also promote the merge of the sub-grain boundaries, leading to a lower density and higher orientational deviation of the sub-grain boundaries.

(An)isotropy measurement with gravitational wave observations

We constrain the distribution of merging compact binaries across the celestial sphere using the GWTC-3 catalog from the LIGO-Virgo-KAGRA Collaborations' (LVK) third observing run. With 63 confident detections from O3, we constrain the relative variability (standard deviation) of the rate density across the sky to be $\ensuremath{\lesssim}16%$ at 90% confidence assuming the logarithm of the rate density is described by a Gaussian random field with correlation length $\ensuremath{\ge}10\ifmmode^\circ\else\textdegree\fi{}$. This tightens to $\ensuremath{\lesssim}3.5%$ when the correlation length is $\ensuremath{\ge}20\ifmmode^\circ\else\textdegree\fi{}$. While the new data provides the tightest constraints on anisotropies available to date, we do not find overwhelming evidence in favor of isotropy, either. A simple counting experiment favors an isotropic distribution by a factor of ${\mathcal{B}}_{\mathrm{ani}}^{\mathrm{iso}}=3.7$, which is nonetheless an improvement of more than a factor of two compared to analogous analyses based on only the LVK's first and second observing runs.

Contrasting dynamics of seed banks and standing vegetation of annuals and perennials along a rainfall gradient

The soil seed bank is a major component of plant communities. However, long-term analyses of the dynamics of the seed bank and the ensuing vegetation are rare. Here, we studied the dynamics in plant communities with high dominance of annuals in Mediterranean, semiarid, and arid ecosystems for nine consecutive years. For annuals, we hypothesized that the density of the seed bank would be more stable than the density of the standing herbaceous vegetation. Moreover, we predicted that differences in temporal variability between the seed bank and the vegetation would increase with aridity, where year-to-year rainfall variability is higher. We found that the temporal variability at the population level (assessed as the standard deviation of the loge-transformed density) of the nine dominant annuals in each site did not differ between the seed bank and the ensuing vegetation in any of the sites. For the total density of annuals, patterns depended on aridity. In the Mediterranean site, the temporal variability was similar in the seed bank and the vegetation (0.40 vs. 0.40). Still, in the semiarid and arid sites, variability in the seed bank was lower than in the vegetation (0.49 vs. 1.01 and 0.63 vs. 1.38, respectively). This difference between the population-level patterns and the total density of annuals can be related to the lower population synchrony in their seed bank. In contrast, for the herbaceous perennials (all species combined), the seed bank variability was higher than in the vegetation. Overall, our results highlight the role of the seed bank in buffering the annual vegetation density with increasing climatic uncertainty typical in aridity gradients. This role is crucial under the increasing uncertainty imposed by climatic change in the region.

Optimization of the control paper production system of using the extremum seeking control method

Currently the pulp and paper industry is one of the fastest growing sectors of the economy in Russia and other countries. An important aspect of the further development of this industry is associated with an increase in the efficiency of paper production and the quality of finished products with an economical and rational use of raw materials, fuel and energy and other material resources. This is facilitated by the use of modern means of automation and process control. It was experimentally established that there is an extreme dependence between the ratio of the speeds of the paper pulp and the paper machine and the standard deviation of the linear density of the paper web, which determines the degree of non-uniformity of the paper gap. The use of a noise-resistant algorithm for extreme control of an inertial object based on the combination of synchronous accumulation and synchronous detection methods with subsequent search for the maximum amplitude of the second harmonic of the filtered signal, aimed at reducing the root-mean-square deviation of the mass of a square meter of paper web, is considered. It is proposed to simultaneously stabilize the mass flow rate of paper pulp and the coordinate of the fall of the paper pulp jet onto the conveyor mesh, which made it possible to increase the efficiency of paper production.

Identifying Flow Patterns in a Narrow Channel via Feature Extraction of Conductivity Measurements with a Support Vector Machine.

In this work, a visualization experiment for rectangular channels was carried out to explore gas-liquid two-phase flow characteristics. Typical flow patterns, including bubble, elastic and mixed flows, were captured by direct imaging technology and the corresponding measurements with fluctuation characteristics were recorded by using an electrical conductivity sensor. Time-domain and frequency-domain characteristics of the corresponding electrical conductivity measurements of each flow pattern were analyzed with a probability density function and a power spectral density curve. The results showed that the feature vectors can be constructed to reflect the time-frequency characteristics of conductivity measurements successfully by introducing the quantized characteristic parameters, including the maximum power of the frequency, the standard deviation of the power spectral density, and the range of the power distribution. Furthermore, the overall recognition rate of the four flow patterns measured by the method was 93.33% based on the support vector machine, and the intelligent two-phase flow-pattern identification method can provide a new technical support for the online recognition of gas-liquid two-phase flow patterns in rectangular channels. It may thus be concluded that this method should be of great significance to ensure the safe and efficient operation of relevant industrial production systems.

Noise pollution prediction and seasonal comparison in urban parks using a coupled GIS- artificial neural network model.

Noise pollution is a challenging environmental issue in densely built urban areas and requires a holistic understanding of its sources and alleviation processes. Taking Isfahan City in Iran as a typical case, this study developed a combined GIS-artificial neural network (ANN) model to predict the spatio-temporal contribution of low-width parks to poise pollution mitigation. The 30-min equivalent sound level was measured at 100 stations in six urban parks (with a total area of 55.84ha) under stable and controlled winter and summer conditions. The noise level predicting variables were hypothesized to be the area of vegetation cover; NDVI-based vegetation density and standard deviation (std); vegetation height; and road coverage measured within 100-, 200-, and 300-m radius buffer rings drown around each noise sampling station. These predictors were introduced to a multi-layer perceptron ANN model to identify and compare the most important noise alleviation variables among the selected predictors. The mean noise levels ranged from 67.23 to 70.57dB. The number of vehicles showed an insignificant temporal difference, indicating that the noise source was relatively constant between the seasons. The ANN model performed satisfactorily in both seasons with SSE values of < 0.03. The Mann-Whitney U test showed a significant difference in the predicted noise levels between summer and winter. This study highlighted the efficiency of the combined GIS-ANN model in predicting distant-dependent urban processes, especially noise pollution whose levels and variability are essential in formulating urban land-use management.

Heterogeneity Aware Emission Macroscopic Fundamental Diagram (e-MFD)

Transportation sector is one of the major producers of greenhouse gases which are responsible for climate change. Finding an appropriate emission estimation tool for large-scale networks is essential for developing efficient emission mitigation strategies. This paper presents an advanced version of the emission macroscopic fundamental diagram (e-MFD) which improves the stability and accuracy of the previous model. A bi-modal function is applied to separate free-flow and congested branches of the e-MFD. The accuracy of the proposed e-MFD is evaluated with both a synthetic grid network and a real-world city-level network. The study also assesses the model’s stability under directional traffic demands and road incidents. A comparison with the original e-MFD also verifies the superiority of the proposed model with higher accuracy. Standard deviation of density used in the proposed model to boost the performance. It is worth mentioning the standard deviation can be recorded with the existing hardware, such as loop detectors, and does not impose a considerable computational complexity. The proposed model can be employed for emission measurement in large-scale networks and hierarchical traffic control systems for more homogeneous congestion distribution and emission control.

Mixture Model for Refrigerant Pairs R-32/1234yf, R-32/1234ze(E), R-1234ze(E)/227ea, R-1234yf/152a, and R-125/1234yf

In this work, thermodynamic models based on the corresponding states framework with departure terms are developed for the refrigerant pairs R-32/1234yf, R-32/1234ze(E), R-1234ze(E)/227ea, R-1234yf/152a, and R-125/1234yf. These models are based on new measurements of density, speed of sound, and phase equilibria, combined with the data available in the literature. The model for R-32/1234yf is most comprehensive in its data coverage, with speed of sound deviations within 1%, density deviations within 0.1%, and bubble- and dew-point pressure deviations within 1%. The other mixtures have generally more limited data availability but a similar goodness of fit.

An in vivo study to assess and compare the angular, linear, and depth deviation as well as the difference in bone density of implants placed using computer-aided design/computer-aided manufacturing fabricated three-dimensional guides versus the implants placed using bone pen kit in maxillary and mandibular ridges.

The aim is to assess and compare angular, linear, and depth deviation and difference in bone density of dental implants placed using computer aided design/computer aided manufacturing (CAD/CAM) fabricated surgical guides versus implants placed using Bone Pen Kit. Till now, no original research exists in the search engines such as Pubmed, Google Scholar, Science Direct, and Research Gate on this kit. In vivo- Randomised control trial. Twenty clinical cases were selected and split into two distinct groups. Group 1 involved the placement of 10 implants using CAD/CAM fabricated three dimensional guides and Group 2 involved the placement of 10 implants using Bone Pen Kit. Four deviation parameters were evaluated, which included: (a) Angular deviation, (b) Linear deviation at implant platform, (c) Linear deviation at implant apex, and (d) Depth deviation and difference in bone density before and after implant placement was also evaluated. SPSS software version 23 was utilized for the analysis of the data. The comparison was made using the Whitney test, and Wilcoxon signed rank test. When comparing angular deviation, the results indicated a statistically significant difference with a P < 0.05. The values observed for angular and linear deviation in Group 2 were significantly greater than those in Group 1. No statistically significant difference in depth and linear deviation was found at the implant platform among the two groups. Bone density before and after implant placement was significantly higher in Group 1. (1) Angular and linear deviation at the apex in Group 2 exhibited higher values in comparison to Group 1, (2) No difference in depth and linear deviation at the implant platform was found among the two groups, and (3) There was no difference in change in bone density among two groups.

Зависимость плотности, твердости, прочности и размеров образцов твердого сплава WC – 15 Co от содержания пластификатора в заготовках, полученных при использовании пластиковой пресс-формы, изготовленной методом 3D-печати

The paper studies influence of the content of the plasticizer (rubber) on the density, microstructure and properties of the WC – 15 Co samples got using a plastic which was made using additive technologies. We have experimentally established that in polylactide molds with strength of 70 MPa, workpieces up to 120 MPa can be pressed. Studies have shown that an increase in the concentration of the plasticizer from 1 % to 4 % leads to an increase in the density of samples from 61 % to 90 % after pressing and a decrease in the density of samples from 99.5 % to 99.3 % after sintering. This is 0.3 – 0.6 % less than the density of samples obtained after pressing in a steel mold at a pressure of 210 MPa. Deviations in density do not affect the microstructure and hardness of the obtained samples, which is 1140 – 1170 HV. Due to the lower density and the presence of individual large pores up to 100 μm in length, the strength of the samples obtained using a plastic mold (1550 – 1980 MPa) turned out to be lower than the strength of the samples obtained using a steel mold (2230 – 2430 MPa). Nevertheless, the density of workpieces and obtained cemented carbide samples turned out to be significantly higher than the density and hardness of samples obtained using existing additive technologies.

A model of random pulsations of radiant heat flow from a flammable liquid fire

The object of the study is the process of liquid combustion in a tank or in a spill. Unlike the standard approach that assumes the shape of the flame is constant, random pulsations of the flame due to the turbulent mode of liquid combustion are considered. The pulsations lead to the random nature of the mutual radiation coefficient and the temperature of the radiating surface of the flame. This leads to a random value of the radiant heat flux density from the fire. Using the central limit theorem allows justifying the assumption about the normal law of the distribution of the radiant heat flux density, the mutual radiation coefficient and the temperature of the radiating surface of the flame. The assumption of a normal distribution law allows calculating the mathematical expectation of the heat flux density. It is shown that the average value of the heat flux density increases with an increase in the dispersion of the temperature of the radiating surface and the coefficient of mutual radiation, as well as with an increase in the correlation coefficient between them. It means that neglecting random flame pulsations can lead to underestimates of the average heat flux density from a fire. The dispersion of the radiant heat flux density was found and it was shown that it increases with the growth of the dispersion of the flame temperature and the mutual radiation coefficient. The standard deviation of the heat flux density can be more than 40 % of its average value if the standard deviations of the flame temperature and the mutual radiation coefficient are up to 10 % of their average values. The obtained results can be used to clarify the thermal effect of a liquid fire on neighboring objects.

Measurement of Transient Flash Evaporation Flow in Liquefied Gas Propulsion Using Dual-Plane ECT

In this paper, the transient flash evaporation flow in liquified gas propulsion (LGP) was measured using a dual-plane electrical capacitance tomography (ECT) sensor. The novelty mainly stems from a selection method for more accurate liquid holdup measurement, a constrained adaptive cross-correlation algorithm for more stable velocity, and compensation methods against the changes of temperature and pressure. By the selection method, inter-electrodes capacitances that contribute less to the flow measurement, are removed from each data frame and more accurate liquid holdup is derived via image reconstruction. The adaptive cross-correlation algorithm with a constraint on the correlation coefficient is adopted to alleviate the adverse effect of the fast changes of flow pattern on the velocity measurement. Then, the compensation methods are realized by correcting the deviations of phase density and permittivity caused by dramatic temperature and pressures changes. Simulations and experiments validated the effectiveness of the proposed methods to derive the mass flow rate of the two-phase flow via the measured liquid holdup, flow velocity and estimated phase density. It is shown that the remaining mass of propellant in the storage tank calculated from the mass flow rate is in good agreement with the measured reference by the electronic balance, where the average relative errors under different initial pressures are less than 10%. As the best of our knowledge, this is the first-time of transient flash evaporation flow measurement in a lab-built LGP device, which is promising to be applied for the effective online control to maximize the output impulse of LGP and estimate the remaining life of small spacecrafts.

MODEL OF FORMATION AND PROPAGATION OF SLIP BANDS IN METALS

A theoretical study of the processes of localization of plastic deformation in metals has been carried out. Within the framework of the system of evolutionary equations for dislocation density, taking into account the multiplication and annihilation of dislocations, the possibility of a running solution for the slip strip is established. It is shown that the initial system has two equilibrium states. For the total dislocation density and dislocation charge normalized to a stationary homogeneous solution for dislocation density, these are the states (0,0) and (1,0) on the phase plane of the above variables in dimensionless form. From the analysis of singular points, it follows that the point (0,0) is a stable node, and the equilibrium state (1,0) is a saddle. In this case, the desired solution of the initial system of evolutionary equations is a separatrix going from point (0,0) to point (1,0), which corresponds to solutions in the form of a drop wave for the dislocation density forming the slip band and a momentum for the dislocation charge. It is shown that the dislocation charge propagates in the front of the slip band, which moves at a velocity u = kV (V is the drift velocity of dislocations due to external load, the proportionality coefficient k satisfies the condition 0 &lt; k &lt; 1). After analyzing the existence of self-similar solutions, it follows that non-homogeneous wave solutions occur only at A = t1/t2 &gt; 1, where t1 and t2 are, respectively, relaxation times of the total dislocation density and dislocation charge to a homogeneous state. Estimates show that for a given dislocation kinetics (dislocation generation and annihilation processes) A &gt; 1, i.e. satisfy the conditions for the formation of a slip strip of a given type. The stability of the obtained wave stationary self-similar solutions is considered. Assuming that deviations from stationary solutions for the dislocation density and dislocation charge are limited to a given domain, and considering the deviations small, we obtain the Sturm – Liouville problem for own functions and eigenvalues with zero boundary conditions at the boundary of this domain. The appropriate transformation reduces the problem to an equation of the Schrodinger equation type. It is shown that under certain conditions the spectrum of the Schrodinger operator is in the left half-plane, i.e. deviations of dislocation density and dislocation charge decay exponentially over time and the desired stationary solutions are asymptotically stable. The issue related to the determination of the steady-state velocity of wave propagation is considered. Linearization of the initial system of equations for dislocation density and dislocation charge allowed us to obtain a linear sine-Gordon equation, from the solution of which the steady-state wave velocity is determined. It is shown that for the initial system of the system of equations for A &gt; 1, arbitrary initial distributions of the desired variables acquire the form of self-similar solutions over time and move at the lowest possible speed u = 2VA1/2/(1 + A).

A Machine Learning Approach to Find Density Percentage Error Resulting by Infill Patterns in Additive Manufacturing

This paper presents employing Machine Learning in predicting the error involved in the output density of the additive manufactured parts. Due to the fact that the density of a 3D part is related to the filled volume inside the body, the characteristics of infill lines become important. The existence of density percentage error is proven in previous studies, and it shows the deviation of actual infill density from the desired input density requested by the user. Since the amount of density error is different for various setups of infill parameters, being able to predict the density percentage error without going through the full calculation provides the base for infill setup optimization with the objective to minimize this error. A procedure is shown on how to work on the density error, by selecting a 2D infill pattern, recognizing the corresponding input parameters, and set up the error estimating. This study represents density percentage error prediction for a generic cubic model using a neural network. The developed results demonstrate the accuracy of the implemented neural network in predicting the density percentage error while the infill input parameters are changed.

The relation between the serum level of glycosylated hemoglobin and corneal endothelial cell loss in phacoemulsification

Abstract Purpose: To evaluate corneal endothelium (CE) changes and function after uneventful phacoemulsification in relation to the level of glycosylated hemoglobin (HbA1c). Patients and Methods: A prospective interventional case-control study was conducted on 76 eyes, divided into two groups: Group 1 included 38 eyes of diabetic patients, which was further divided into three subgroups according to the level of HbA1c; Group A (strict control HbA1c &lt; 7 mg/dL), Group B (moderate control HbA1c 7–9 mg/dL), and Group C (poorly controlled HbA1c &gt; 9 mg/dL), and Group 2 included 38 eyes of nondiabetic patients. All participants had a full ophthalmological examination, assessment of the level of HbA1c, preoperative evaluation of CE by specular microscopy, uneventful phacoemulsification, and reassessment of CE by specular microscopy 3 weeks after surgery. Results: Three weeks after surgery, statistically significant changes in CE parameters regarding endothelial cell density, ACG, and standard deviation in both groups were found, with greater changes in diabetics. The poorer the control of diabetes (higher preoperative HbA1c), the greater the impact on postoperative CE changes, but the changes were of no statistical significance. Conclusion: Diabetics are more vulnerable to CE damage during phacoemulsification, and the higher the preoperative HbA1c, the more the damage. So, strict preoperative diabetic control is advisable before phacoemulsification.

The spatial distribution characteristics of autogenous medium and its effect on low rank lignite beneficiation in differential-motion dry cascade beneficiation bed

In the mining process, a large amount of inorganic mineral impurities are produced, leading to the grade reduction of lignite. Promoting the efficient separation and utilization of low rank lignite is the key measure to stabilize energy structure. In this paper, differential-motion dry cascade separation bed was used for separation, ash reduction and upgrading for low rank lignite. The spatial distribution characteristics of 1.5–0 mm pulverized coal particles in the differential-motion dry cascade separation bed was emphatically investigated. The influence of selecting 1.5–0 mm pulverized coal particles as autogenous medium on the uniformity and stability of bed density was systematically analyzed. The interlayer distribution law of low rank lignite in differential-motion dry cascade separation bed was dissected. The results shows that the leading particle size fraction and the leading density fraction of autogenous medium particles are d = 0.25–0.125 mm, ρ = 1.8–2.0 g/cm3, respectively and the autogenous medium particles could be diffused uniformly and stably along XOY and XOZ cross section and could form autogenous medium fluidized bed with uniform and stable density. When the pulverized coal particle size d = 0.25–0.125 mm, the average bed density reaches the maximum value of 1.815 g/cm3 and the standard deviation of bed density reaches the minimum value of 0.029, at this time, the stability of bed space density reaches the optimum. When the leading density fraction of pulverized coal is 1.8–2.0 g/cm3, the distribution range of bed density is 1.81–1.82 g/cm3 and the fluctuation amplitude is 0.01 g/cm3, at this time, the density of autogenous medium bed is uniform and stable. The interlayer distribution law of low rank lignite in the separation bed was determined. The ash content of upper layer materials is distributed relatively uniform and the distribution range is 9.44–9.76 % with small fluctuation amplitude. The ash content distribution fluctuation of middle layer materials is large and the distribution range is 18.69–31.02 %. The ash content of lower layer materials is distributed relatively uniformly and the distribution range is 41.22–42.06 %. The low rank lignite was separated and upgraded. The ash content of clean coal is 9.58 % and the yield is 63.14 %. The ash content of gangue is 42.09 % and the yield is 36.86 %. The probable error is 0.11 g/cm3. The separated products are relatively pure and the efficient ash reduction and upgrading for low rank lignite are realized.