Parameters Of Degradation Process Research Articles

Insight into the degradation of carbamazepine by electrochemical-pressure UV-activated peroxodisulphate process: kinetics, radicals, and degradation pathway

ABSTRACT In this work, to improve the performance of peroxodisulphate-advanced oxidation, an electrochemical oxidation-assisted UV light-activated peroxodisulphate system (E/UV/PDS) was used to degrade carbamazepine. The degradation of carbamazepine by PDS, E/PDS, UV/PDS and E/UV/PDS systems was compared, and their synergistic effects were analysed. The influence of single factors, such as PDS addition, initial pH, DS voltage, target initial concentration, etc., on the degradation of the E/UV/PDS system was discussed, and the optimal degradation process parameters were given. The active substances were determined by free radical inhibition experiments, such as 1O2, SO 4 − ⋅ and ⋅ OH . It was proved that 1O2 contributes much more to the degradation of carbamazepine than SO 4 − ⋅ and ⋅ OH . The degradation pathway of carbamazepine was proposed. Finally, the degradation mechanism of carbamazepine in the E/UV/PDS system was speculated. The results indicate that the electrochemical combined with the E/UV/PDS system is of great potential application value in the removal of antibiotic drug pollution and environmental purification.

Подход к определению срока сохраняемости электрорадиоизделий бортовой аппаратуры авиационной техники применительно к установленной модели внешних воздействующих факторов

The article deals with challenges arising from the application of electronic components in airborne electronic hardware, which are in the standby / storage mode and de-energized most of the time when not in use, as well they are regularly checked for the proper functioning. The article also discusses some possible solutions to these problems. A technique for assessing storage ability indicators is proposed based on the electronic component properties characterization for the standby / storage mode. The technique is implemented on mathematical models using the activation energy values of the physical-chemical degradation process parameters of the electronic components in airborne equipment. The application of mathematical models addressed to solve the denoted problems can allow author to predict the dependability of electronic products. Some calculations and a comparative analysis of values of all parameters characterized the shortest storage ability period at higher temperature are presented for several groups of electronic components in airborne equipment

Waste coal cinder catalyst enhanced electrocatalytic oxidation and persulfate advanced oxidation for the degradation of sulfadiazine.

Waste coal cinder, a kind of waste cinder discharged from coal combustion of thermal power plants, industrial and civil boilers, and other equipment, was rich in metal oxides with catalytic activity. In this work, waste coal cinder was used to enhance electrochemical coupling peroxymonosulfate (PMS) advanced oxidation degradation of sulfadiazine (SD). The surface morphology, elemental composition, and electrocatalytic activity of waste coal cinder were characterized by various characterization instruments. The results show that compared with simple electrocatalytic oxidation, electrocatalytic oxidation+waste coal cinder and electrocatalytic coupled persulfate oxidation, electrocatalytic oxidation+PMS advanced oxidation+waste coal cinder has the largest removal efficiency (99.95%) and mineralization rates (90.16%) of SD in 90min, indicating that the introduction of waste coal cinder greatly increases the degradation efficiency. •OH and SO4-• were detected during the process of degradation. The optimal degradation process parameters were explored through different voltage, pH, plate spacing, aeration flow rate, potassium peroxymonosulfate sulfate complex salt dose, and Na2SO4 dosage. Cycling experiments show waste coal cinder has good structural stability. Through the analysis of triple quadrupole liquid chromatography-mass spectrometry (LC-MS), we put forward three possible ways of SD degradation. This research will provide a novel vision for water treatment.

Insight into the high-efficient electrocatalytic elimination toward antibiotics via introducing FeTiO3 interlayer under Ce-PbO2 coating

At present, the development of high-efficient electrocatalyst is still of great urgency for efficiently eliminating the refractory antibiotics. Herein, a novel Ti/FeTiO3/Ce-PbO2 laminated electrode (TFCP) is firstly constructed via introducing FeTiO3 interlayer into the Ti/Ce-PbO2 (TCP). After systematical investigation on the Ti/FeTiO3 (TF), TCP and TFCP anode with scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) measurements, the electrocatalytic properties of these electrocatalysts have been compared by checking electrocatalytic degradation towards levofloxacin (LEVO) antibiotics coupled with systematical optimization on the electrode preparation conditions and electrocatalytic degradation process parameters. Dramatically, the optimal TFCP delivers higher removal 95% of LEVO within 120 min than those of TF (63%) and TCP (49%). Quite obviously, the introduction of FeTiO3 interlayer is the important reason for the enhanced electrocatalytic activity of TCP, which can give rise to larger electrochemical active surface area, moderate electrochemical resistance and higher oxygen evolution potential (OEP) of TFCP than those of the TF and TCP electrodes. Also, TFCP shows predominant reusability for repeated utilization and desirable wide-applicability for other antibiotics and dyes removal. The degradation pathway has been presumably speculated by analyzing the intermediates. In conclusion, this work paves a novel avenue for the highly efficient electrocatalytic degradation towards antibiotics by introducing the interlayer into the TCP.

Bimetallic modified halloysite particle electrode enhanced electrocatalytic oxidation for the degradation of sulfanilamide

The treatment of antibiotics wastewater by electrocatalytic oxidation has attracted much attention. In the paper, a novel halloysite bimetallic (HLS-Cu-Mn) particle electrode material was prepared and a bench-scale electrocatalytic reaction tank was designed. A three-dimensional electrocatalytic oxidation reactor composed of HLS-Cu-Mn and a bench-scale electrocatalytic reaction tank was used to degrade Sulfanilamide (SA) wastewater. Characterization of the synthesized material was conducted with Scanning electron microscopy (SEM), X-ray polycrystalline powder diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). The electron spin resonance spectroscopy test results confirmed that HLS-Cu-Mn produced a large number of •OH. The electrochemical workstation confirmed that HLS-Cu-Mn had strong electrocatalytic activity and repolarization ability. Under the optimum preparation conditions and degradation process parameters, the removal efficiency of SA and TOC was 99.84% and 88.95% respectively. The method also has good degradation efficiency for aniline, phenol, herbicides, antibiotics, and dyeing wastewater. It was found that 4 main intermediates appeared in the degradation process by Ultra-high performance liquid chromatography/triple tandem quadrupole mass spectrometry (LC-MS). In sum, it was believed that this work provides a new vision and idea for water treatment.

Modeling cyclic volatile methylsiloxanes removal efficiency from wastewater by ZnO-coated aluminum anode using artificial neural networks

Usage of cyclic volatile methyl siloxanes (cVMSs) in the industrial process is unavoidable due to their superior properties; however, it is hazardous to human health. Photocatalytic zinc oxide coated aluminum anode is used to degrade the cVMSs in wastewater. In this work, we investigated the relationship among degradation process parameters such as current density (4–20 mA/cm2), initial pH (5–9), plate distance (8–24 cm), UV intensity (0–120 W), and reaction time (30–100 min) vis-a-vis cVMSs removal efficiency by using data-driven artificial neural networks(ANN) model. The ANN model was trained using a backpropagation algorithm with the sigmoid activation function between input, hidden, and the output layers. Two hidden layers with eight neurons in each layer presented the minimum average training error (0.24) and higher (0.99) correlation coefficient values (both Pearson’s r and Adj. R2) as compared with the conventional regression model. The effect and relationship between the parameters and cVMSs removal efficiency were analyzed by single, two variable sensitivity analysis, qualitative and quantitative estimation.

On Condition Maintenance Model for Complex Electromechanical Equipments Based on Remaining Useful Life and Wiener Process

Aiming at the problem of condition based maintenance modeling for complex electromechanical equipment, a condition based maintenance model based on residual life prediction and improved Wiener process is proposed; first of all, for the degradation process character of complex electromechanical equipment, this paper proposes a residual life prediction model based on random coefficient Wiener process; To estimate the parameters of degradation process, a prior distribution construction method based on state data is proposed; And the posterior distribution and estimation of degradation process parameters are constructed by Bayes theory, and the remaining life prediction of equipment in operation is realized. Secondly, the decision model of condition based maintenance is established by balancing the reliability and economy targets with the information of remaining life; And the immune particle swarm optimization algorithm is used to solve the model. The case study shows that the residual life prediction model proposed in this paper has higher prediction accuracy and lower prediction uncertainty, the condition based maintenance decision-making model is more practical, has higher operational reliability and economy, and the convergence accuracy of the model solving algorithm is higher.

Optimization of process parameters for degradation of HMX with Bacillus toyonensis using response surface methodology

Contamination of soil and water with explosive compounds like octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX or commonly known as high melting explosives) is increasing day by day due to their extensive use all over the world. High level of contamination has been found near military sites, explosive manufacturing facilities, war-lands, mines and exercise ranges. Remediation of such contaminants is necessary as they may have adverse impact on biotic as well as on abiotic environment. Present study was carried out with an objective to optimize the variable process parameters for the degradation of HMX in aqueous phase by indigenously isolated bacterial strain, Bacillus toyonensis from an actual HMX contaminated site in North India using response surface methodology. The relationship among varying initial concentrations of HMX, microbial inoculum size and degradation time was revealed in the current study. Results showed that 87.7% degradation was achieved at 2 mg/L initial HMX concentration with inoculum size of 4% on 15th day. High regression coefficient value (0.9878) further supported predictability of experimental data. Nitrite and nitrate concentrations estimated during the experiment indicate breakdown and degradation process of HMX. Findings of this study concluded that Bacillus toyonensis can be a potential microorganism to degrade HMX and can be used for microbial remediation of HMX contaminated sites.

Electro-activated persulfate oxidation of malachite green by boron-doped diamond (BDD) anode: effect of degradation process parameters.

In this paper, boron-doped diamond (BDD) electro-activated persulfate was studied to decompose malachite green (MG). The degradation results indicate that the decolorization performance of MG for the BDD electro-activated persulfate (BDD-EAP) system is 3.37 times that of BDD electrochemical oxidation (BDD-EO) system, and BDD-EAP system also exhibited an enhanced total organic content (TOC) removal (2.2 times) compared with BDD-EO system. Besides, the degradation parameters such as persulfate concentration, current density, and pH were studied in detail. In a wider range of pH (2-10), the MG can be efficiently removed (>95%) in 0.02 M persulfate solution with a low current density of 1.7 mA/cm2 after 30 min. The BDD-EAP technology decomposes organic compounds without the diffusion limitation and avoids pH adjustment, which makes the EO treatment of organic wastewater more efficient and more economical.

Thermal Stability Evaluation of Polystyrene-Mg/Zn/Al LDH Nanocomposites.

A series of samples of Mg/Zn/Al LDHs (layered double hydroxides) materials was prepared by the co-precipitation and urea hydrolysis methods. They were modified with organic surfactants (acrylate and oleate anions) and characterized by X-ray diffraction, which corroborated the intercalation of anionic species into the interlayer space. The hydrophobized materials were incorporated at low contents (10 and 15 wt.%) to polystyrene, which was synthesized by emulsion polymerization techniques. The polymeric composites were analyzed by thermogravimetry to determine the decomposition temperature. The results demonstrated that the materials with Zn presented the greatest increment in the degradation temperature (7 °C < T < 54 °C). Moreover, the Friedman, Flynn–Wall–Ozawa, and Coats–Redfern models were compared to obtain the kinetic parameters of degradation process. The obtained order of decomposition of the Coats–Redfern model showed that the decomposition process occurs in at least two stages. Finally, the addition of environmentally friendly modified Layered Double Hydroxides (LDH) nanomaterials to the polystyrene (PS) matrix allowed for obtaining polymeric composites with higher thermal stability, retarding the decomposition process of PS.

Non-homogenous gamma process: Application to SiC MOSFET threshold voltage instability

The accelerated degradation tests provide the opportunity to assess the reliability of an electronic component for which only parametric degradation is observable. In the case of the silicon carbide MOSFETs, this approach makes it possible to study the impact of the threshold voltage phenomenon on the reliability of the devices. During the High Temperature Gate Bias tests, we have carried out, the threshold voltage of the ten devices under test have been monitored and their degradation modeled using a non-homogeneous Gamma process. The estimation of the degradation process parameters enable to estimate the distribution of the first hitting time to a degradation threshold which is considered as a failure criterion. Lastly, a criterion proposed by Tseng and Yu [1] has been used to provide a metric to stop these ageing tests while having relevant reliability data.

Theoretical and experimental studies of Cu(II) and Zn(II) coordination compounds with N,O donor bidentate Schiff base ligand containing amino phenol moiety

We report here two mononuclear Cu(II) and Zn(II) coordination compounds of general formula [CuII(L)2].2H2O (1) and [ZnII(L)2].3H2O (2) derived from bidentate 2-chloro-6-{[(4-hydroxy-3-methoxyphenyl)methylidene]amino}-4 nitrophenol ligand (HL). These compounds were synthesized and characterized by elemental analysis, FT-IR, uv–vis, 1H NMR, molar conductance, thermal, PXRD, SEM-EDX and electrochemical studies. The PXRD and SEM analysis shows the amorphous/nanocrystalline nature of 1 and crystalline nature of 2. The diffraction peak broadening was explained in terms of domain size and the crystallite lattice strain. Thermogravimetric analysis in the range of 300–1172 K has been performed to determine the thermal stability of synthesized compounds. The non-isothermal kinetic parameters of degradation process were calculated using Coats-Redfern (C-R), Piloyan–Novikova (P–N) and Horowitz–Metzger (H–M) methods assuming first order degradation and proposed a random nucleation mechanism of thermal decomposition for both compounds. The cyclic voltammetric studies reveal the irreversibility of the oxidation/reduction process of synthesized compounds. To support the experimental findings theoretical calculations by means of DFT and TD-DFT at B3LYP level were incorporated. In addition; frequency calculations, HOMO–LUMO, energy gap (ΔE), molecular electrostatic potential (MEP), spin density and crystal packing were also computed at the same level of theory.

Microbe Selection and Optimizing Process Parameters for Degradation of Glucosinolates in Rapeseed Meal by Box-Behnken Design

The present study applied Aspergillus oryzae, Aspergillus niger, Penicillium purpurogenum, Trichoderma sp. MAB-2010b and Saccharomyces cerevisiae in solid state fermentation to degrade the glucosinolates in rapeseed meal. In addition, SDS-PAGE was used to determine the effect of hydrolysis of those five microbes on peptide size in rapeseed meal. The results indicated that the solid state fermentation with S. cerevisiae degraded the glucosinolates more than those with other microbes. The peptides were hydrolyzed by S. cerevisiae to a greater extent than others. Thus the following procedure was just focused on the solid state fermentation with S. cerevisiae. Box-Behnken design of response surface methodology was applied to optimize the substrate to water ratio, inoculum amount, and duration. The glucosinolate level in rapeseed meal was as the response. The optimal conditions derived from response surface methodology for S. cerevisiae fermentation were: 1.0 of substrate to water ratio, 1.5 mL (equal to 5%) of inoculum amount, and 48 h of duration. The minimum content of glucosinolates was 0.46 μmol/g dry matter. S. cerevisiae used in the present study thus exhibit the potential use in large scale solid state fermentation for increasing nutrition quality of rapeseed meal.

Degradation prognosis based on a model of Gamma process mixture

A novel method is proposed to exploit jointly degradation measurements originating from a set of identical systems for making a degradation prognosis. The systems experience differentdegradation processes depending on operational conditions. The degradation processes are assumed to be Gamma processes. The aim is to cluster the degradation paths in classes corresponding to the different operational conditions in order to group properly the data for the estimation of degradation process parameters. A model of Gamma process mixture is considered and an expectation-minimization approach is proposed to estimate the unknown parameters. The feasibility of the method is shown on simulated cases. Prognosis results obtained with the proposed method are compared with results obtained with basic strategies (considering each system alone or all system together).

Transformation and Products Distribution of Moso Bamboo and Derived Components During Pyrolysis

Transformation and products distribution of moso bamboo (Phyllostachys edulis) and its derived components during pyrolysis were investigated by thermogravimetric analyzer coupled with Fourier transform infrared spectrometry (TG-FTIR) and analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) techniques. The pyrolysis of moso bamboo was generally an integrated result of the decomposition of its several derived components by examining the degradation process parameters and pyrolysis kinetics. The main peaks of the infrared (IR) spectrum for gases released at the highest intensity were assigned to be CO2, CO, CH4, H2O, acids, aldehydes, aromatics, ethers, and alcohols. Pyrolysis temperature played an important role in the products distribution of moso bamboo by affecting the products' yield and secondary cracking of heavy compounds. 500 °C was an inflection point for product release during moso bamboo pyrolysis. Further cracking of aromatic compounds and furans into lighter products was observed with increasing pyrolysis temperature.

Photocatalytic Treatment of MO in Water with BiOBr Photocatalyst

The BiOBr catalyst prepared by the hydrolysis method was investigated with the X-ray diffractometry(XRD) and scanning electron microscope (SEM). The results show that the catalyst was the tetragonal primitive crystal structure and composed of homogeneous particles of fine ferrite plates. At the same time, the photocatalytic activity of BiOBr catalyst was evaluated by methylene orange (MO) in aqueous solution illuminated by Xenon lamp, and the degradation process parameters, such as initial concentration of MO, initial pH value and amount of BiOBr catalyst were discussed to the degradation rate of the MO. Under the following experimental conditions of C0=10mg/L, pH=8, m(BiOBr)=1.0g/L, MO can be entirely degraded after 2.5 hours.