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Background: Early prediction of delayed cerebral ischemia (DCI) is critical to improving the prognosis of aneurysmal subarachnoid hemorrhage (aSAH). Machine learning (ML) algorithms can learn from intricate information unbiasedly and facilitate the early identification of clinical outcomes. This study aimed to construct and compare the ability of different ML models to predict DCI after aSAH. Then, we identified and analyzed the essential risk of DCI occurrence by preoperative clinical scores and postoperative laboratory test results. Methods: This was a multicenter, retrospective cohort study. A total of 1039 post-operation patients with aSAH were finally included from three hospitals in China. The training group contained 919 patients, and the test group comprised 120 patients. We used five popular machine-learning algorithms to construct the models. The area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, precision, and f1 score were used to evaluate and compare the five models. Finally, we performed a Shapley Additive exPlanations analysis for the model with the best performance and significance analysis for each feature. Results: A total of 239 patients with aSAH (23.003%) developed DCI after the operation. Our results showed that in the test cohort, Random Forest (RF) had an AUC of 0.79, which was better than other models. The five most important features for predicting DCI in the RF model were the admitted modified Rankin Scale, D-Dimer, intracranial parenchymal hematoma, neutrophil/lymphocyte ratio, and Fisher score. Interestingly, clamping or embolization for the aneurysm treatment was the fourth button-down risk factor in the ML model. Conclusions: In this multicenter study, we compared five ML methods, among which RF performed the best in DCI prediction. In addition, the essential risks were identified to help clinicians monitor the patients at high risk for DCI more precisely and facilitate timely intervention. [ABSTRACT FROM AUTHOR]

Background: Coronary inflammation induces changes in pericoronary adipose tissue (PCAT) can be detected by coronary computed tomography angiography (CCTA). Our aim was to investigate whether different PCAT radiomics model based on CCTA could improve the prediction of major adverse cardiovascular events (MACE) within 3 years. Methods: This retrospective study included 141 consecutive patients with MACE and matched to patients with non-MACE (n = 141). Patients were randomly assigned into training and test datasets at a ratio of 8:2. After the robust radiomics features were selected by using the Spearman correlation analysis and the least absolute shrinkage and selection operator, radiomics models were built based on different machine learning algorithms. The clinical model was then calculated according to independent clinical risk factors. Finally, an overall model was established using the radiomics features and the clinical factors. Performance of the models was evaluated for discrimination degree, calibration degree, and clinical usefulness. Results: The diagnostic performance of the PCAT model was superior to that of the RCA-model, LAD-model, and LCX-model alone, with AUCs of 0.723, 0.675, 0.664, and 0.623, respectively. The overall model showed superior diagnostic performance than that of the PCAT-model and Cli-model, with AUCs of 0.797, 0.723, and 0.706, respectively. Calibration curve showed good fitness of the overall model, and decision curve analyze demonstrated that the model provides greater clinical benefit. Conclusion: The CCTA-based PCAT radiomics features of three major coronary arteries have the potential to be used as a predictor for MACE. The overall model incorporating the radiomics features and clinical factors offered significantly higher discrimination ability for MACE than using radiomics or clinical factors alone. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to explore the relationship between quantitative epicardial adipose tissue (EAT) based on coronary computed tomography angiography (CCTA) and coronary slow flow (CSF). Methods: A total of 85 patients with < 40% coronary stenosis on diagnostic coronary angiography were included in this retrospective study between January 2020 and December 2021. A semi-automatic method was developed for EAT quantification on CCTA images. According to the thrombolysis in myocardial infarction flow grade, the patients were divided into CSF group (n = 39) and normal coronary flow group (n = 46). Multivariate logistic regression was used to explore the relationship between EAT and CSF. Receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic value of EAT in CSF. Results: EAT volume in the CSF group was significantly higher than that of the normal coronary flow group (128.83± 21.59 mL vs. 101.87± 18.56 mL, P < 0.001). There was no significant difference in epicardial fat attenuation index between the two groups (P > 0.05). Multivariate logistic regression analysis showed that EAT volume was independently related to CSF [odds ratio (OR) = 4.82, 95% confidence interval (CI): 3.06–7.27, P < 0.001]. The area under ROC curve for EAT volume in identifying CSF was 0.86 (95% CI: 0.77–0.95). The optimal cutoff value of 118.46 mL yielded a sensitivity of 0.80 and a specificity of 0.94. Conclusions: Increased EAT volume based on CCTA is strongly associated with CSF. This preliminary finding paves the way for future and larger studies aimed to definitively recognize the diagnostic value of EAT in CSF. [ABSTRACT FROM AUTHOR]

Background: Studies on coronary slow flow are receiving increasing attention, but objective evaluations are still lacking. The purpose of this study was to visualize the current status and research hotspots of coronary slow flow through bibliometric analysis. Methods: All relevant publications on coronary slow flow from 2003 to 2022 were extracted from the Web of Science Core Collection database and analyzed by VOSviewer and CiteSpace visualization software. Year of publication, journal, country/region, institution, and first author of each paper, as well as research hotspots were identified. Results: A total of 913 publications were retrieved. The journal with the most publications was Coronary Artery Disease. The country/region with the most publications was Turkey, followed by China and the United States. The institution with the largest publication volume was Turkey Specialized Higher Education Research Hospital. The author with the largest publication volume was Chun-Yan Ma from China. Keyword analysis indicated that "treatment and prognosis", "pathogenesis and risk factors" and "diagnosis" were the clustering centers of coronary slow flow, and the research hotspots gradually changed with time, from pathogenesis to treatment and prognosis. Conclusion: Future research will focus on the search for effective and non-invasive detection indicators and treatments of coronary slow flow. Collaboration needs to be enhanced between different institutions or countries/regions, which would improve clinical outcomes for patients with coronary slow flow. [ABSTRACT FROM AUTHOR]

Finding promising materials that show large thermoelectricity at low temperatures is crucial for low-temperature refrigeration applications. Here, we report a significantly large thermoelectric power factor (PF) up to 50 μW cm−1 K−2 at an extremely low temperature of ∼8 K in a quasi-one-dimensional (Q1D) antiferromagnet KMn6Bi5, in which highly electrical conductivity and dramatic enhancement of Seebeck coefficient may favor its occurrence. In addition, a giant Nernst signal has also been detected with a maximum value of 24 μV K−1 T−1 at ∼5 K. All these intriguing characteristics observed in KMn6Bi5 can be attributed to the manifestation of the unusually strong coupling among spin, charge, lattice, and one dimensionality in KMn6Bi5. Our findings provide fundamental insight into the thermal transport in Q1D antiferromagnets and should stimulate further experimental exploration of thermal transport in such Q1D family for possible thermoelectric applications at extremely low temperatures. [ABSTRACT FROM AUTHOR]

To assess the performance of biplane area-length method in measuring left atrial (LA) volume and sphericity index and to investigate the correlation of LA reservoir function and sphericity index with atrial fibrosis on cardiac magnetic resonance imaging (MRI) in patients with mitral valve disease (MVD). Forty-eight patients with MVD undergoing cardiac MRI scan were enrolled in this retrospective study. LA reservoir function, measured as maximum volume (LAVmax), minimum volume (LAVmin) and ejection fraction (LAEF), and sphericity index were quantified using the biplane area-length method and standard short-axis approach, respectively. Comparisons of LA reservoir function and sphericity index between the two different methods were performed, as well as between positive (n = 17, 35%) and negative atrial wall fibrosis groups (n = 31, 65%). There was no difference in the values of LAVmax index and sphericity index between the two different methods. The biplane area-length method had poor performance in assessing LAVmin index and LAEF compared to standard short-axis approach, with an underestimation of 13.5% for LAVmin index and an overestimation of 27% for LAEF. Patients with positive atrial fibrosis had larger LAVmax index, LAVmin index and sphericity index, and lower LAEF levels in comparison to the negative atrial fibrosis group. The biplane area-length method has good performance in assessing LA sphericity index for patients with MVD, not in LA reservoir function. Patients with positive atrial fibrosis tend to suffer from more adverse LA remodelling. [ABSTRACT FROM AUTHOR]

DISCUSSION Effectiveness of PAs with different baselines Our results suggested that 170 of the 338 PAs (50.30%) had significant positive effects, including 150 PAs with low HPI baselines, 12 PAs with medium HPI baselines, and 8 PAs with high HPI baselines (Figure 2b). Our previous studies also showed that unlike PAs with high HPI or medium HPI baselines, PAs with low HPI baselines are more likely to have effective management if they have good patrol and surveillance, which helps control illegal threats in PAs (Wang et al., 2021). Compared with PAs with low HPI and medium HPI baselines, the area of forests in PAs with high HPI baselines of built-up area was relatively higher (Appendix S2). From 2010 to 2020, the rate of forest area decrease was the fastest for PAs with high HPI baselines, followed by PAs with medium HPI baselines and PAs with low HPI baselines (Figure 4a). [Extracted from the article]

Background: The ideal treatment strategy for stable three-vessel coronary artery disease (CAD) patients are difficult to determine and for patients undergoing conservative treatment, imaging evidence of coronary atherosclerotic severity progression remains limited. Epicardial fat volume (EFV) on coronary CT angiography (CCTA) has been considered to be associated with coronary atherosclerosis. Therefore, this study aims to evaluate the relationship between EFV level and coronary atherosclerosis severity in three-vessel CAD.Methods: This retrospective study enrolled 252 consecutive patients with three-vessel CAD and 252 normal control group participants who underwent CCTA between January 2018 and December 2019. A semi-automatic method was developed for EFV quantification on CCTA images, standardized by body surface area. Coronary atherosclerosis severity was evaluated and scored by the number of coronary arteries with ≥ 50% stenosis on coronary angiography. Patients were subdivided into groups on the basis of lesion severity: mild (score = 3 vessels, n = 85), moderate (3.5 vessels ≤ score < 4 vessels, n = 82), and severe (4 vessels ≤ score ≤ 7 vessels, n = 85). The independent sample t-test, analysis of variance, and logistic regression analysis were used to evaluate the associations between EFV level and severity of coronary atherosclerosis.Results: Compared with normal controls, three-vessel CAD patients had significantly higher EFV level (65 ± 22 mL/m2 vs. 48 ± 19 mL/m2; P < 0.001). In patients with three-vessel CAD, there was a progressive decline in EFV level as the score of coronary atherosclerosis severity increased, especially in those patients with a body mass index (BMI) ≥ 25 kg/m2 (75 ± 21 mL/m2 vs. 72 ± 22 mL/m2 vs. 62 ± 17 mL/m2; P < 0.05). Multivariable regression analysis showed that both BMI (OR 3.40, 95% CI 2.00-5.78, P < 0.001) and the score of coronary atherosclerosis severity (OR 0.49, 95% CI 0.26-0.93, P < 0.05) were independently related to the change of EFV level.Conclusion: Three-vessel CAD patients do have higher EFV level than the normal controls. While, there may be an inverse relationship between EFV level and the severity of coronary atherosclerosis in patients with three-vessel CAD. [ABSTRACT FROM AUTHOR]

For continuous monitoring of cardiovascular diseases, this article presents a novel framework for heart sound acquisition. The proposed approach uses compressed sensing for signal sampling, and a two-stage reconstruction is developed for reconstruction. The first stage aims to give a tentative recovered signal, on which a peak detection technique is developed to identify whether there is a peak in current segment and, if so, its location. With such information, an adaptive dictionary is selected for the second round reconstruction. Because the selected dictionary is adaptive to the morphology of current frame, the signal reconstruction performance is consequently promoted. Experiment results indicate that a satisfactory performance can be obtained when the frame length is 256 and the signal morphology is divided into 16 categories. Furthermore, the proposed algorithm is compared with a series of counterparts, and the results well demonstrate the advantages of our proposal, especially at high compression ratios. [ABSTRACT FROM AUTHOR]

The movement behavior of titanomagnerite ore material particles in rotary kiln was simulated by EDEM discrete element simulation software. The results show that the probability accumulation of particles will occur in the process falling down, and ricing again, forming discrete plies along the axis direction of the rotary kiln. The reaction area can be divided into nine fluctuation periods with an average period length of 0. 666 m. According to the calculation of enthalpy of endothermic reduction reaction, the fluctuation range of energy in a single cycle accounts for 29. 79% of the average value of enthalpy of reaction, and the average fluctuation energy in a single cycle of reaction time (500 s) is deduced as E=25.58 MJ, which is easy to cause energy instability. The direct reduction iron production can be carried out by attaching fine pulverized coal on the ore material particles, and using external coal pellets to reduce energy fluctuation by buffering local overheating. [ABSTRACT FROM AUTHOR]

We report the transport properties of a topological insulator candidate, LiMgBi. The electric resistivity of the title compound exhibits a metal-to-semiconductor-like transition at around 160 K and tends to saturation below 50 K. At low temperatures, the magnetoresistance is up to ∼260 % at 9 T and a clear weak antilocalization effect is observed in the low magnetic-field region. The Hall measurement reveals that LiMgBi is a multiband system, where hole-type carriers (n h ∼ 1018 cmâˆ'3) play a major role in the transport process. Remarkably, LiMgBi possess a large Seebeck coefficient ∼440 ÎĽV/K) and a moderate thermal conductivity at room temperature, which indicate that LiMgBi is a promising candidate in thermoelectric applications. [ABSTRACT FROM AUTHOR]

This paper presents an improved reconstruction approach for compressed sensing based ECG acquisition in Internet of Medical Things. The proposed method exploits the concepts of adaptive overcomplete dictionary and QRS detection in CS domain. Based on whether there is a QRS complex, the ECG frames to be reconstructed are divided into several categories and corresponding overcomplete dictionaries are trained to fit these different kinds of ECG frames. Specifically, QRS detection is first performed directly on the compressed measurements to determine the QRS morphology without actually reconstructing the signal in advance, and then a suitable overcomplete dictionary is chosen for the signal reconstruction. Because the selected dictionaries well fit the ECG frames, the reconstruction quality is consequently improved. Comparative experiments have been conducted, and the results well demonstrate the performance of the proposed approach. [ABSTRACT FROM AUTHOR]

Superconducting circuit quantum electrodynamics (QED) architecture composed of superconducting qubit and resonator is a powerful platform for exploring quantum physics and quantum information processing. By employing techniques developed for superconducting quantum computing, we experimentally investigate phase-sensitive Landau–Zener–Stückelberg (LZS) interference phenomena in a circuit QED. Our experiments cover an extensive range of LZS transition parameters and demonstrate the LZS induced Rabi-like oscillation as well as phase-dependent steady-state population. [ABSTRACT FROM AUTHOR]

The preparation of functional material titanium carbide by the carbothermal reduction of Ti-bearing blast furnace slag with microwave heating is an effective method for valuable metals recovery; it can alleviate the environmental pressure caused by slag stocking. The dynamic dielectric parameters of Ti-bearing blast furnace slag/pulverized coal mixture under high-temperature heating are measured by the cylindrical resonant cavity perturbation method. Combining the transient dipole and large n bond delocalization polarization phenomena, the interaction mechanism of the microwave macroscopic non-thermal effect on the titanium carbide synthesis reaction was revealed. The material thickness range during microwave heating was optimized by the joint analysis of penetration depth and reflection loss, which is of great significance to the design of the microwave reactor for the carbothermal reduction of Ti-bearing blast furnace slag. [ABSTRACT FROM AUTHOR]

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In this paper, the research progress and application of ozonation technology in hydrometallurgy of non-ferrous metals are reviewed, focusing on the fields of precious metals, heavy metals, rare metals, light metals, etc. Moreover, the mechanism of ozone oxidation on leaching of low-grade ores including gold and silver and refractory metal ores with high impurities such as sulfur, arsenic and carbon, oxidative precipitation of low-valent metal ions such as antimony, nickel and cobalt, and purification of solutions and removal of impurities such as iron and manganese are discussed in detail. In addition, the application prospects of ozonation technology in non-ferrous metal hydrometallurgy are forecasted. [ABSTRACT FROM AUTHOR]

Methamphetamine abuse has become a serious public health problem. However, effective treatment for methamphetamine addiction remains elusive, especially considering its high rate of relapse after treatment. A conditioned stimulus (CS) memory retrieval–extinction procedure has been demonstrated to decrease reinstatement of cocaine, heroin, and alcohol seeking in rats, and to reduce cue-induced cravings in heroin and nicotine addicts. The goal of the present study is to explore the effect of the CS memory retrieval–extinction procedure on methamphetamine seeking in rats and the underlying mechanisms. We found that daily retrieval of methamphetamine-associated memories 1 h before extinction sessions decreased subsequent drug priming-induced reinstatement, spontaneous recovery, and renewal of methamphetamine seeking. We also found that retrieval of methamphetamine-associated memories induced neuronal activation in the basolateral amygdala (BLA), while presenting extinction within the time window of reconsolidation abolished the neuronal activation in BLA. These results indicate that the CS memory retrieval–extinction procedure could prevent reconsolidation of methamphetamine memory traces in BLA and subsequent methamphetamine craving and relapse. [ABSTRACT FROM AUTHOR]

Posttraumatic stress disorder (PTSD) is an anxiety disorder characterized by intrusive recollections of a severe traumatic event and hyperarousal following exposure to the event. Human and animal studies have shown that the change of amygdala activity after traumatic stress may contribute to occurrences of some symptoms or behaviors of the patients or animals with PTSD. However, it is still unknown how the neuronal activation of different sub-regions in amygdala changes during the development of PTSD. In the present study, we used single prolonged stress (SPS) procedure to obtain the animal model of PTSD, and found that 1 day after SPS, there were normal anxiety behavior and extinction of fear memory in rats which were accompanied by a reduced proportion of activated glutamatergic neurons and increased proportion of activated GABAergic neurons in basolateral amygdala (BLA). About 10 days after SPS, we observed enhanced anxiety and impaired extinction of fear memory with increased activated both glutamatergic and GABAergic neurons in BLA and increased activated GABAergic neurons in central amygdala (CeA). These results indicate that during early and late phase after traumatic stress, distinct patterns of activation of glutamatergic neurons and GABAergic neurons are displayed in amygdala, which may be implicated in the development of PTSD. [ABSTRACT FROM AUTHOR]

Copper and cobalt usually coexist in the leachate of waste lithium ion batteries, sea nodules and other copper ore or by-product. Conventional methods for the separation of copper and cobalt hardly avoid some defects, such as longer extraction time, co-extraction and too many stages. In this paper, a microfluidic extraction procedure for simultaneously separating copper (Cu2+) and cobalt (Co2+) ions in a microchannel was investigated. In addition, some key operation parameters, such as initial pH, volume flow rate and extractant concentration, were optimized by a method of response surface methodology (RSM). The result showed that under the optimized operation parameters of initial pH of 2.5, volume flow rate of 0.035mLmin-1 and extractant concentration of 17.36%, the extraction rate of copper could be as high as 96.73%, with a low cobalt extraction rate, which was only 2.41%. [ABSTRACT FROM AUTHOR]

Composite cathodes composed of LiV(PO) and multiwall carbon nanotubes (MWCNTs) for high-performance Li-ion batteries were synthesized via a fast sol-gel method, using ascorbic acid as reductive reagent and carbon source, while using MWCNTs as high conductivity modifier. Due to the synergistic effect between functional groups of MWCNTs and reductive functionality of ascorbic acid, MWCNTs were uniformly embedded into LiV(PO)@C for constructing a unique three-dimensional architecture with excellent electronic and ionic conductivity to achieve superior high rate performance. When tested as a cathode material in lithium-ion batteries, the optimal LiV(PO)@MWCNTs@C composite can deliver 123.5 mAh g of specific capacity at 5 C and maintain a capacity retention of 96.3% after 300 cycles; even after cycled at 15-C rate for 300 times, it still possesses 90.2 mAh g of specific capacity, demonstrating a great promising result for cathode alternative in high-power lithium-ion batteries. [ABSTRACT FROM AUTHOR]

The preparation of microsized hematite powder from ferrous sulfate using microwave calcination was investigated based on the TG/DTG curves. The decomposition of industrial ferrous sulfate under air atmosphere was divided into three stages, and a ferrous sulfate sample added with 15% FeO could strongly absorb microwave energy. Therefore, preparing hematite powder from ferrous sulfate using microwave calcination was feasible. Hematite was obtained under the following optimized conditions: calcination temperature, 850 °C; microwave power, 650 W; and sample amount, 40 g. The obtained hematite satisfied the first-grade quality requirements. The total ferrum value was more than 58%, and the total sulfur and phosphorus contents were less than 0.5% and 0.2%, respectively. X-ray powder diffraction and scanning electron microscopy were used to characterize the structure and morphology of microsized hematite powder. The particles were non-spherical in shape, and the average particle size distribution was 10.45 μm. This work provides new potential applications for waste ferrous sulfate. [ABSTRACT FROM AUTHOR]

In this paper, powder metallurgy technology combined with high-pressure sintering (HPS) were used to fabricate MnTe ( x = −0.02, 0, 0.04) alloys at 743 K. The products of synthesis were identified by x-ray diffraction; microstructures were examined by field-emission scanning electron microscopy (FE-SEM); the electrical conductivity and the Seebeck coefficient were measured in the temperature range of 300-800 K. The results show that all HPS samples consisted of nanoparticles. MnTe ( x = −0.02, 0, 0.04) thermoelectric materials with a high Seebeck coefficient and low electrical conductivity have potential to warrant further study in the future. The peak figure of the merit, ZT, reaches 0.59 for MnTe at 773 K. [ABSTRACT FROM AUTHOR]

This paper presents a solution to satisfy the increasing requirements for secure medical image transmission and storage over public networks. The proposed scheme can simultaneously encrypt and compress the medical image using compressive sensing (CS) and pixel swapping based permutation approach. In the CS phase, the plain image is compressed and encrypted by chaos-based Bernoulli measurement matrix, which is generated under the control of the introduced Chebyshev map. The quantized measurements are then encrypted by permutation-diffusion type chaotic cipher for the second level protection. Simulations and extensive security analyses have been performed. The results demonstrate that at a large scale of compression ratio the proposed cryptosystem can provide satisfactory security level and reconstruction quality. [ABSTRACT FROM AUTHOR]

This paper presents a solution to satisfy the increasing requirement of real-time secure image transmission over public networks. The main advantage of the proposed cryptosystem is high efficiency. The confusion and diffusion operations are both performed based on a lookup table. Therefore, the time-consuming floating point arithmetic in chaotic map iteration and quantization procedures of traditional chaos-based image cipher can be avoided. Besides, this cryptosystem possesses satisfactory resistance to noise perturbation and loss of cipher data, which are inevitable and unpredictable in real-world channels. The channel disturbance and the deliberate damage from the opponents are both tolerated. The recovered image from the damaged cipher data has satisfactory visual perception. Simulations prove the advantages of the proposed scheme, which render it a good candidate for real-time secure image applications. [ABSTRACT FROM AUTHOR]

Nowadays, the increasing demand for telemedicine services has raised interest in the real-time medical image protection literatures. In this paper, we evaluate the security of an efficient and secure medical image protection scheme recently proposed (Fu et al., 2013). It is found that this scheme can be successfully broken by launching chosen-plaintext attacks. Improvement is subsequently developed for promoting the security and efficiency performance. Extensive security analyses and experimental results both indicate that the improved scheme can well address the security flaws and advance the speed performance of the original one. [ABSTRACT FROM AUTHOR]

The technology that waste activated carbon after extracting gold is regenerated with steam under microwave heating was studied. The influence of the activation temperature, activation duration and steam flow rate on iodine adsorption value and regeneration yield of activated carbon was investigated. The response surface methodology (RSM) technique was utilized to optimize the process conditions. The optimum conditions for the preparation of activated carbon are identified to be activation temperature of 831 °C, activation duration of 40 min and steam flow rate of 2.67 mL/min. The optimum conditions result in an activated carbon with an iodine number of 1048 mg/g and a yield of 40%, and the BET surface area evaluated using nitrogen adsorption isotherm is 1493 m/g, with total pore volume of 1.242 cm/g. And the pore structure of activated carbon regenerated is mainly composed of micropores and a small amount of mesopores. [ABSTRACT FROM AUTHOR]

Traditional treatments of zinc dross have many disadvantages, such as complicated recovering process and serious environmental pollution. In this work, a new process of chlorine removal from zinc dross by microwave was proposed for solving problem of recycling the zinc dross. With better ability of absorbing the microwave than zinc oxide, the main material in zinc dross, chlorides, can be heated and evaporated rapidly during microwave roasting. Various parameters including roasting temperature, duration time and stirring speed were optimized. The microstructure of roasted materials was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The content of the chloride was analyzed by the method of chlorine ion selective electrode. The experiments indicate that the best duration time is 60 min with a stirring speed of 15 r/min during the microwave roasting process. The dechlorination rate reaches peak value of 88% at 700 °C. The chlorine is removed as HCl gas when water vapor is used as activating agent, which means that it can be recovered into hydrochloride acid. [ABSTRACT FROM AUTHOR]

Most Zn hydrometallurgy factories adopt CuSO as a dechlorination reagent from zinc solution nowadays, thus much CuCl residue is produced. The existing process of treating this residue is washing with water or sodium carbonate solution, which would cause a lot of troubles to water treatment and waste discharge. A method of microwave roasting was adopted for dechlorination of CuCl residue. A 1.5 kW microwave roasting equipment with dust collection and tail gas adsorption systems was set up and applied during the experiment. By investigating the effect of temperature, heat preservation time, moisture content of raw material and grain size of samples on the dechlorination, the optimal experimental condition is obtained. When the samples with 2% moisture and <150 μm grain size are microwave roasted at 400 °C for 2 h, the Cl content turns from 14.27% to 1.35% and the dechlorination rate is as high as 90%, while that with conventional heating is only 60%-80%. The phase change of the roasting process investigated with X-ray diffraction verifies that CuCl in CuCl residue is removed by being transformed into CuO. [ABSTRACT FROM AUTHOR]

The dielectric properties of petroleum coke at five temperatures between 20 to100∘C, covering different moisture content levels at 2.45 GHz, were measured using an open-ended coaxial probe dielectric measurement system. The effects of drying temperature, duration of drying, and sample mass on the moisture content and dehydration rate of petroleum coke was assessed utilizing the response surface methodology. The dielectric constant, loss factor, and loss tangent were all found to increase nearly linearly with increase in moisture content. Three predictive empirical models were developed to relate the dielectric constant, loss factor, and loss tangent of petroleum coke as a linear function of moisture content from 3–10%. An increase in temperature between 20 to100∘Cwas found to increase the dielectric properties. The penetration depth was observed to increase linearly with decrease in moisture content in the range of 3 to 10%. A predictive empirical model was developed to calculate penetration depth for petroleum coke. Two mathematical models were established and analyzed using RSM to describe the relationship between the microwave drying conditions and the responses, moisture content, and dehydration rate. Statistical analysis with response surface regression showed that microwave drying temperature, duration of drying, and sample mass were significantly related to moisture content and dehydration rate. Based on the RSM analysis, the optimum process conditions were estimated to be a microwave drying temperature of75∘C, drying duration of 10 sec, and sample mass of 60 g, with the resultant moisture content being 0.34 at a dehydration rate of 2.94 g/min. [ABSTRACT FROM PUBLISHER]

The central composite process optimization was performed by response surface methodology technique using a design for the treatment of methyltin mercaptide with modified semi-coke. The semi-coke from the coal industry was suitably modified by treating it with phosphoric acid, with a thermal activation process. The objective of the process optimization is to reduce the chemical oxygen demand (COD) and NH-N in the methyltin mercaptide industrial effluent. The process variables considered for process optimization are the semi-coke dosage, adsorption time and effluent pH. The optimized process conditions are identified to be a semi-coke dosage of 80 g/L, adsorption time of 90 min and a pH value of 8.34. The ANOVA results indicate that the adsorbent dosage and pH are the significant parameters, while the adsorption time is insignificant, possibly owing to the large range of adsorption time chosen. The textural characteristics of modified semi-coke were analyzed using scanning electron microscopy and nitrogen adsorption isotherm. The average BET surface area of modified semi-coke is estimated to be 915 m/g, with the average pore volume of 0.71 cm/g and a average pore diameter of 3.09 nm, with micropore volume contributing to 52.36%. [ABSTRACT FROM AUTHOR]

Spent coal-based activated carbon from the silicon industry has been used as raw material for the regeneration of activated carbon, with carbon dioxide as the regenerating agent. The regeneration process was optimised using response surface methodology and the optimum regeneration conditions were: regeneration temperature 985 °C; regeneration time 120 min; and carbon dioxide flow rate of 600 ml/min. The iodine number and yield of the activated carbon obtained under the optimum regeneration conditions were 1071 mg/g and 67%, with a Brunauer-Emmet-Teller surface area of 1270 m2/g and pore volume of 0.91 cm3/g. The regenerated carbon was tested for the removal of Methylene Blue dyes. The maximum adsorption capacity was found to be 395 mg/g and the equilibrium data fitted to the Langmuir isotherm model. The kinetic data indicated that the best fit corresponds to the pseudo-second-order kinetic model. [ABSTRACT FROM AUTHOR]

An extensive experimental study has been attempted to assess the effect of heating method and the activation agent on the pore characteristics of activated carbon from coconut shell. The results show that the textural characteristics of activated carbon improve with increase in holding time until an optimum, while the yield decrease with an increase in the holding time, using conventional activation method. The microwave heating requires significantly lesser holding time as compared to conventional heating method, to produce activated carbon of comparable quality, with higher yield. The BET surface area of steam activated carbon using microwave heating is significantly higher than the conventional heating, however with CO activation microwave heating shows only a marginal increase in BET surface area as compared to conventional heating. The activated carbon prepared using microwave heating has a surface area of 1,684 m/g with steam activation, while CO activation has a surface area of 1,716 m/g, which is significantly higher than the majority of the surface area reported in literature using conventional physical activation. [ABSTRACT FROM AUTHOR]

The microwave absorbing characteristics of basic cobalt carbonate, cobalt oxide (CoO), and the mixture of basic cobalt carbonate and cobalt oxide were investigated by means of microwave cavity perturbation, their temperature increasing curves were measured, and their ability to absorb microwave energy was also assessed based on the temperature increasing behavior of the material exposed to microwave field. Analyses of spectrum attenuation and relative frequency shift show that basic cobalt carbonate has weak capability to absorb microwave energy, while cobalt oxide has very strong capability to absorb microwave energy. It is feasible to thermally decompose basic cobalt carbonate though addition of small amount of cobalt oxide in microwave fields. The capability to absorb microwave energy of sample increases with an increase in mixing ratio of CoO. [ABSTRACT FROM AUTHOR]

Microwave absorbing properties of high titanium slag were investigated by using microwave cavity perturbation technique. High titanium slag containing more than 90% TiO2 was prepared by carbothermal reduction of ilmenite. The temperature rise curve of high titanium slag in microwave heating process was obtained. Crystalline compounds of high titanium slag before and after microwave irradiation were obtained and characterized by X-ray diffractometry (XRD). Effects of particle size of high titanium slag and mixtures of high titanium slag with different mass fractions of V2O5 on microwave absorbing properties were investigated systematically. The results show that high titanium slag has good microwave absorption property; untreated high titanium slag mainly consists of crystalline compounds of anatase and iron titanium oxide, while the microwave-irradiation treated one is mainly composed of crystalline compounds of rutile and iron titanium oxide. Synthetic anatase is transformed completely into rutile at about 1 050 °C for 20 min under microwave irradiation. High frequency shift and low amplitude of voltage make high titanium slag an ideal microwave absorbent. 180 μm of particle size and 10% mass fraction of V2O5 are found to be the optimum conditions for microwave absorption. [ABSTRACT FROM AUTHOR]