Decomposition Yield Research Articles

Synergistic improvement of straw decomposition and rice yield in saline sodic paddy soils by rational nitrogen application

Synergistic improvement of straw decomposition and rice yield in saline sodic paddy soils by rational nitrogen application

Numerical study of bischofite precursor droplet evaporation and thermal decomposition for spray pyrolysis systems

Understanding the evaporation and decomposition process of bischofite precursor droplets in a pyrolysis furnace is the prerequisite for designing an efficient spray bischofite treatment facility. However, current research lacks guidance on this behavior. Here, it provided a new theoretical basis for understanding evaporation characteristics and decomposition behavior by introducing the Abramzon-Sirignano and kinetics models. In addition, the effects of ambient temperature and relative humidity on the evaporation characteristics of different precursors were analyzed. Meanwhile, the decomposition products and yield changes were studied in detail under different temperatures and times. The results show that the mass transfer coefficient and latent heat of vaporization have the most significant influence on droplet evaporation. To high recovery rate, the reaction temperature must be above 1125 °C. The current work can guide obtaining high magnesium oxide yield from waste bischofite in pyrolysis.

Energy Partition between Submesoscale Internal Waves and Quasigeostrophic Vortical Motion in the Pycnocline

Abstract Shipboard ADCP velocity and towed CTD chain density measurements from the eastern North Pacific pycnocline are used to segregate energy between linear internal waves (IW) and linear vortical motion [quasigeostrophy (QG)] in 2D wavenumber space spanning submesoscale horizontal wavelengths λx ∼ 1–50 km and finescale vertical wavelengths λz ∼ 7–100 m. Helmholtz decomposition and a new Burger number (Bu) decomposition yield similar results despite different methodologies. While these wavelengths are conventionally attributed to internal waves, both QG and IW contribute significantly at all measured scales. Partition between IW and QG total energies depends on Bu. For Bu < 0.01, available potential energy EP exceeds horizontal kinetic energy EK and is contributed mostly by QG. In contrast, energy is nearly equipartitioned between QG and IW for Bu ≫ 1. For Bu < 2, EK is contributed mainly by IW, and EP by QG, while, for Bu > 2, contributions are reversed. Finescale near-inertial IW dominate vertical shear variance, implying negligible QG contribution to vertical shear instability. In contrast, both QG and IW at the smallest λx ∼ 1 km contribute large horizontal shear variance, so that both may lead to horizontal shear instability, while QG, with its longer time scales, likely dominates isopycnal stirring. Both QG and IW contribute to vortex stretching at small vertical scales. For QG, the relative vorticity contribution to linear potential vorticity anomaly increases with decreasing horizontal and increasing vertical scales.

Cu-ZnO/CdS/rGO tertiary heterojunction for improved photocatalytic degradation of synthetic dyes using visible light

A novel tertiary heterojunction based on Cu-ZnO/CdS/rGO was successfully designed and produced from graphite, Zn2+. Cu2+, and Cd2+ precursors. The produced materials underwent thorough characterization, including microstructure, surface charges, chemical groups, elemental composition, as well as optical properties. The Cu-ZnO/CdS/rGO photocatalytic system exhibited a response to visible light, with an Eg = 1.8 eV, leading to a capability of generating efficient charge carriers by visible light irradiation. The combination of Cu-ZnO/CdS/rGO led to a reduction in recombination rate of charge carriers. Various factors such as pH, catalyst load, pollutant concentration, and reaction time, were methodically investigated for their influence on photocatalytic degradation of Direct Blue 71 (DB 71).The developed Cu-ZnO/CdS/rGO heterojunction exhibited a significant improvement in decomposition yield compared to individual components (from 1.26 to 2.0-fold). Under optimal conditions (pH 6.5 and 500 mg/L catalyst load), over 93 % of 0.05 g/L DB 71 were decomposed in just 100 min by visible light catalyzed by Cu-ZnO/CdS/rGO system, and the decomposition process fit the best the pseudo-1st-order kinetics, with coefficients in the range of 0.889 to 0.983. The primary species responsible for DB 71 degradation was the (O2•-), revealing that graphene sheets of reduced graphene oxide (rGO) might play an important role for electron transfer and react with dissolved O2 molecules to generate O2•-. This research introduces an innovative method to develop an efficient and feasible photocatalytic system, offering potential for use in practical wastewater treatment systems dealing with synthetic dye contamination.

Low-temperature catalytic oxidation of PCDD/Fs over MnCeCoOx/PPS catalytic filter.

Catalytic destruction of nitrogen oxides (NOx) combined with dust removal technique has attracted much attention, yet the application in the solid waste incineration air pollution control process is still lacking due to the complex flue gas atmosphere. In this work, the Mn-Ce-Co-Ox catalyst-coated polyphenylene sulfide (PPS) filter fiber with efficient dust removal and low-temperature polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) destruction has been prepared with a redox-precipitation method. The catalyst was uniformly grown around the PPS fiber with appropriate catalyst loading. The effects of several key operating parameters (e.g., reaction temperature, catalyst loading amount, and filtration velocity) on the catalytic efficiency were comprehensively investigated. The results show that the Mn-Ce-Co-Ox/PPS has a decomposition yield of 78.0% in PCDD/Fs and 96% in nitric oxide (NO) conversion at 200 °C. The poisoned catalytic filter exhibits a removal efficiency of 88.6% for PCDD/Fs. In addition, the catalytic filter can completely reject particles smaller than 1.0 μm with a low filtration resistance. Therefore, this efficient and energy-conserving catalytic filter shows promising applications in flue gas pollution treatments.

Copper slag assisted coke reduction of phosphogypsum for sulphur dioxide preparation

The reduction of phosphogypsum (PG) to lime slag and SO2 using coke can effectively alleviate the environmental problems caused by PG. However, the PG decomposition temperature remains high and the product yield remains poor. By adding additives, the decomposition temperature can be further reduced and PG decomposition rate and product yield can be improved. However, the use of current additives such as Fe2O3 and SiO2 brings the problem of increasing economic cost. Therefore, it is proposed to use solid waste copper slag (CS) as a new additive to reduce PG to prepare SO2, which can reduce the cost and meet the environmental benefits at the same time. The effects of proportion, temperature and thermostatic time on PG decomposition are investigated by experimental and kinetic analysis combined with FactSage thermodynamic calculations to optimize the roasting conditions. Finally, the reaction mechanism is proposed. It is found that adding CS to the coke and PG system can increase the rate of PG decomposition and SO2 yield while lowering the PG decomposition temperature. For example, when the CS/PG mass ratio increases from 0 to 1, PG decomposition rate increases from 83.38% to 99.35%, SO2 yield increases from 78.62% to 96.81%, and PG decomposition temperature decreases from 992.4 °C to 949.6 °C. The optimal reaction parameters are CS/PG mass ratio of 1, Coke/PG mass ratio of 0.06 at 1100 °C for 20 min with 99.35% PG decomposition rate and 96.81% SO2 yield. The process proceeds according to the following reactions: 2CaSO4+ 0.7C + 0.8Fe2SiO4→0.8Ca2SiO4+ 0.2Ca2Fe2O5+ 0.4Fe3O4+ 2SO2+ 0.7CO2 Finally, a process for decomposing PG with coke and CS is proposed.

General analytical solution expressions for analyzing Langmuir-type kinetics of sonochemical degradation of nonvolatile organic contaminants in water

Detailed kinetic studies of the ultrasonic decomposition of contaminants in water are scarce. Most of the work has used a pseudo-first order kinetics law, which is unrealistic. The model based on a Langmuir-type mechanism has been shown to fit the sonolytic decomposition data well, especially by using the non-linear technique. To avoid unrealistic assumptions, general analytical solutions to a time-dependent non-linear Langmuir-type equation may be the appropriate method. In this work, the sonolytic oxidation of organic contaminants, i.e., naphthol blue black and furosemide, in water was analyzed using two general analytical solution expressions of the Langmuir-type kinetics model, which describe the pollutant concentration in water. The validity of the two general analytical solution expressions was tested under a diversity of operating conditions, such as initial substrate concentration and varying ultrasonication frequency and intensity. As the initial substrate concentration increased, the sonolytic oxidation kinetics decreased, while the initial ultrasonic decomposition rate increased and then plateaued. Consequently, a heterogeneous kinetics equation based on a Langmuir-type mechanism can be used to simulate the sono-decomposition process. The decomposition yield increased with increasing sonication intensity and decreasing frequency. The two analytical solution expressions seem to be in excellent agreement with the experimental results of the sonochemical decomposition of the nonvolatile organic contaminants tested for the different operating conditions examined. These expressions provide a valuable tool for the analysis and simulation of advanced sonochemical oxidation processes under various experimental conditions.

Improvement of straw decomposition and rice growth through co-application of straw-decomposing inoculants and ammonium nitrogen fertilizer

BackgroundThe growth of rice is reduced by the slow decomposition of accumulated straw, which competes with rice for soil nitrogen nutrient. In recent year, straw-decomposing inoculants (SDIs) that can accelerate straw decomposition and ammonium nitrogen (N) fertilizer that can quickly generate available N is increasingly adopted in China. However, it is still unknown whether the N demand of straw decomposition and crop growth can be simultaneously met through the co-application of SDIs and ammonium N fertilizer.ResultsIn this study, we investigated the effect of the co-application of SDIs and ammonium bicarbonate on decomposition rate of wheat straw, rice growth and rice yield over two consecutive years in rice-wheat rotation system. Compound fertilizer (A0) was used as control. The ratios of ammonium bicarbonate addition were 20% (A2), 30% (A3) and 40% (A4), respectively, without SDIs or with SDIs (IA2, IA3, IA4). Our results revealed that without SDIs, compared with A0, straw decomposition rate, rice growth and yield were improved under A2; However, under A3, rice yield was decreased due to the slow decomposition rate of straw and limited growth of rice during late growth stage. Combining SDIs and N fertilizer increased straw decomposition rate, rice growth rate and yield more than that of N fertilizer alone, especially under IA3. Compared with A0, straw decomposition rate, tiller number, aboveground biomass, leaf area index, root length, and nitrogen use efficiency were significantly increased by 16%, 8%, 27%, 12%, 17%, and 15% under IA3. Consequently, the average rice yield of IA3 was increased to 10,856 kg/ha, which was 13% and 9% higher, respectively, than of A0 and A2.ConclusionOur results indicated that ammonium bicarbonate application alone carried a risk of nutrient deficiency during late growth stage and yield decline. Therefore, the co-application of SDIs and 30% ammonium N fertilizer substitution can be a favorable practice to simultaneously accelerate straw decomposition and increase rice crop growth.

High-density Surface EMG Decomposition by Combining Iterative Convolution Kernel Compensation with an Energy-specific peel-off Strategy.

Objective- This study aims to develop a novel framework for high-density surface electromyography (HD-sEMG) signal decomposition with superior decomposition yield and accuracy, especially for low-energy MUs. Methods- An iterative convolution kernel compensation-peel off (ICKC-P) framework is proposed, which consists of three steps: decomposition of the motor units (MUs) with relatively large energy by using the iterative convolution kernel compensation (ICKC) method and extraction of low-energy MUs with a Post-Processor and novel 'peel-off' strategy. Results- The performance of the proposed framework was evaluated by both simulated and experimental HD-sEMG signals. Our simulation results demonstrated that, with 120 simulated MUs, the proposed framework extracts more MUs compared to K-means convolutional kernel compensation (KmCKC) approach across six noise levels. And the proposed 'peel-off' strategy estimates more accurate MUAP waveforms at six noise levels than the 'peel-off' strategy proposed in the progressive FastICA peel-off (PFP) framework. For the experimental sEMG signals recorded from biceps brachii, an average of 16.1 ± 3.4 MUs were identified from each contraction, while only 10.0 ± 2.8 MUs were acquired by the KmCKC method. Conclusion- The high yield and accuracy of MUs decomposed from simulated and experimental HD-sEMG signals demonstrate the superiority of the proposed framework in decomposing low-energy MUs compared to existing methods for HD-sEMG signal decomposition. Significance- The proposed framework enables us to construct a more representative motor unit pool, consequently enhancing our understanding pertaining to various neuropathological conditions and providing invaluable information for the diagnosis and treatment of neuromuscular disorders and motor neuron diseases.

Gamma radiolytic decomposition of methylparaben for environmental protection purposes

The methyl ester of p-hydroxybenzoic acid (methylparaben, MP) is commonly used as a preservative in cosmetics, food and pharmaceuticals. Its widely examined interactions with aqueous system and human organisms prove a necessity of the monitoring of its release to natural environment and the efficiency of its removal from waters and wastewaters.In this work, the yield of MP decomposition in aqueous solutions by gamma-radiation was investigated under oxidative conditions. The LC/MS, GC/MS and ion-chromatography were employed for examination of the yield of MP decomposition in function of the absorbed dose of radiation and for identification of stable products derived from MP formed during radiolysis prior to its complete mineralization. The studies were carried out in aerated aqueous solutions and under conditions with the predominance of OH radicals. The mechanisms of radical reactions were proposed leading to formation of the identified stable products. The irradiation of aerated MP solutions was assumed as a more favorable condition in terms of the yield of MP decomposition and a lack of changes of cytotoxicity towards 3 human cell lines was found. Under such conditions a 90% decomposition of MP at initial concentration 0.5 mg L−1 was observed for 100 Gy absorbed dose, which for the employed 60Co γ -source took 3.3 min. This provides a much better efficiency of MP decomposition in comparison to most of developed AOPs for this purpose.

On the global behavior of linear flows

For linear flows on vector bundles, it is analyzed when subbundles in the Selgrade decomposition yield chain transitive subsets for the induced flow on the associated Poincaré sphere bundle.

Growth performance in Horticulture: Temporal dynamics under different crop groups in India

The present study aims at analyzing the growth performance of Horticulture in India. The paper analyzes the growth rates and decomposition analysis of horticultural crop groups’ area, production and productivity from 1991-92 to 2020-21. The study period was divided into pre-NHM (1991-92 to 2004-05) and post-NHM (2005-06 to 2020-21). The compound growth rate results show that the growth rate in area, production and productivity of horticultural crop groups are positive and statistically significant during the post-NHM period than the pre-NHM period. From decomposition analysis, area effect and yield effect are positive during the post-NHM period for all the crop groups; the interaction effect also shows positive except for fruits and flower crops. The overall performance in area, production, and productivity is quite satisfactory during the post-NHM period; greater attention needs to be given to the states where productivity has declined with marginal increments under NHM.

Decomposition of hexane and benzene by dielectric barrier discharge plasma and reaction temperature: Comparison of performance of DC nano-second pulsed power supply and AC high voltage power supply

The VOC decomposition performance of a dielectric barrier discharge plasma powered by a DC nano-second pulsed power system was compared with that of an AC high voltage power system. Benzene and hexane were selected as a representative aromatic VOC and a chain-structured VOC, respectively, and the decomposition of each VOC was conducted at the same applied voltage in both systems. The energy of electrons released from the plasma was analyzed, and the ozone production ability was evaluated under a constant applied voltage at different temperatures. Compared with AC high voltage system, the DC nano-second pulsed power system had about 32 times, 26 times, and 30 times better performances for ozone production yield, benzene decomposition yield, and hexane decomposition yield, respectively. For benzene decomposition, the ring cleavage reaction was constant at all reaction temperatures. On the other hand, the mineralization of hexane was largely improved by higher temperatures, because the dehydrogenation reaction was accelerated. Consequently, benzene decomposition was easier than hexane decomposition at the same energy.

Efficient photodegradation of PFOA using spherical BiOBr modified TiO2 via hole-remained oxidation mechanism

Photo-induced holes (h+) oxidation is an efficient approach for perfluorooctanoic acid (PFOA; C7F15COOH) removal. To maintain a high amount of h+ on the surface of photocatalysts participating in the PFOA photodegradation could be a critical issue. Herein, a highly efficient spherical BiOBr-modified nano-TiO2 (P25) was synthesised and used for PFOA photodegradation through direct oxidation with h+. A high number of h+ could be generated and remain on the surface of P25/BiOBr due to the appropriate position of the conduction band (CB) and valence band (VB) levels between P25 and BiOBr. Meanwhile, PFOA molecules were coordinated to the P25/BiOBr's surface via unidentate binding, being directly activated and oxidised by h+, resulting in a decomposition yield of 99.5% (100 mg/L) under simulated solar light irradiation within 100 min, at the initial pH condition (3.5). A stepwise photodegradation pathway was proposed due to the significant intermediates detected as the short-chain perfluorinated carboxylic acids (C2–C7). Reactive oxygen species (ROS) generation, scavenging and trapping analysis indicated that the direct oxidation on h+ followed PFOA degradation. In a real aqueous environment of Tangxun lake (adjusted pH 3.5), stable common anions and natural organic matter (NOM) would restrain the PFOA photodegradation. However, adding 10 mg/L of NO3− or HA could reduce the inhibition effect of PFOA photodegradation. These findings gave an alternative strategy to drive an h+ directly oxidation to treat PFOA contaminated water bodies.

Efficient extraction of tungsten from scheelite with phosphate and fluoride

Considering the problems of high temperature and large reagent consumption in the current alkali decomposition processes, phosphate and fluoride were adopted to extract tungsten from scheelite. The results indicated that tungsten could be efficiently extracted with a decomposition rate of> 98.0% under moderate decomposition conditions, forming fluorapatite in the decomposition residue. The decomposition yield is influenced by the calcium fluoride dosage, decomposition temperature, liquid-to-solid ratio, and holding time. Furthermore, the decomposition reaction followed the surface chemical reaction controlling step. Additionally, the phosphorus concentration in the decomposition solution was lower than 0.2 g/L. This work may provide an alternative for the efficient tungsten extraction from scheelite, especially fluorite bearing scheelite under relatively low reagent costs and temperature.

Decomposition of diclofenac in sewage from municipal wastewater treatment plant using ionizing radiation

Abstract The decomposition of diclofenac (DCF) in sewage sludge from municipal wastewater treatment plant was investigated. It was found that adsorption of DCF on sludge is about 40%. Compared to previous studies, where the degradation yield in aqueous solution was 100%, in those experiments at the dose up to 5 kGy, only 50% of initial DCF concentration of 50 mg L−1 was decomposed in sediment and in solution over the sediment. The experiments were carried out using both gamma radiation and electron beam. It has been observed that DCF in the aqueous phase, above the sediment, was decomposed with the same efficiency using both gamma radiation and electron beam. Whereas for DCF in the sediment, a higher degradation efficiency was found when gamma radiation was applied. This is most likely due to the limited penetration depth of the electron beam into the sludge layer. It was shown that the applied peroxide addition (in a stoichiometric amount needed for complete mineralization of 50 mg L−1 DCF) did not cause increase in yield of DCF decomposition.

Automatic decomposition of pediatric high density surface EMG: A pilot study

This pilot study presents a novel application of high density surface electromyography (EMG) decomposition in pediatric patients, with a view toward promoting its potential clinical application for examination of pediatric neuromuscular diseases. Automatic progressive FastICA peel-off (APFP) framework was used to decompose high density surface EMG signals recorded from the first dorsal interosseous and abductor pollicis brevis muscles of children with spinal muscular atrophy. The performance of the decomposition with reduced EMG recording channels was also investigated. In total 131 motor units were extracted from 15 trials of 64-channel (8 ​× ​8) surface EMG. The decomposition yield reduced to 102 motor units when 36-channel (6 ​× ​6) was used, among which 84 motor units were common ones with an average matching rate of (95.68 ​± ​5.26) %. The decomposition yield further reduced to 65 motor units when only 16-channel (4 ​× ​4) was used, among which 57 were common ones with an average matching rate of (95.99 ​± ​4.56) %. These results indicate that using the APFP framework single motor unit activity can be reliably and automatically extracted from pediatric surface EMG signals recorded by an electrode array, which can facilitate potential clinical application of surface EMG as an alternative or supplement to invasive needle EMG for examination of neuromuscular diseases in children.

The combination of different nitrogen fertilizer types could promote rice growth by alleviating the inhibition of straw decomposition

AbstractStraw return plays an important role in the improvement of farmland ecological environments, increasing soil fertility, crop quality, and yield. However, in the early growth of rice (Oryza sativa L.), straw decomposition and rice growth may be inhibited by suboptimal carbon/nitrogen (C/N) ratios. We, therefore, explored methods that could alleviate the inhibition of straw decomposition using different combinations of ammonium bicarbonate and compound fertilizer. No fertilizer (CK) and compound fertilizer (S0) were used as the control. The ratios of added ammonium bicarbonate were 10% (S1), 20% (S2), 30% (S3), and 40% (S4), respectively. Compared with the S0 treatment, the S2 treatment accelerated straw decomposition, promoted the early growth of tillers and roots, and improved the leaf area index, dry matter accumulation, and N use efficiency (apparent N utilization, agronomic N utilization, and partial factor productivity increased by 4.05‒19.48% in two years). Moreover, panicle number, filled‐grain percentage, and 1000‐grain weight were significantly higher in the S2 treatment than other treatments. The grain yield of S2 treatment was significantly higher than that of S0 treatment by 4.06% (2019) and 5.66% (2020). Regression analysis revealed that the optimal ratios of ammonium bicarbonate for increasing straw decomposition and grain yield were relatively close, 16.27% and 14.60%, respectively. These results suggest that compared with conventional fertilization method (S0), the 20% treatment is a more effective fertilization method that prevents inhibition of straw decomposition, promoting rice growth and yield, and improving nitrogen (N) use efficiency.

Co-application of nitrogen and straw-decomposing microbial inoculant enhanced wheat straw decomposition and rice yield in a paddy soil

Straw returning is a promising approach to improve soil fertility and to mitigate the negative effects of chemical fertilizers on soil quality. However, straw degradation is a slow and multifactorial-controlled process. Herein, a field experiment (June 2010–September 2013) was carried out to examine the effects of concurrent application of chemical nitrogen (N) and straw-decomposing microbial inoculant (SDMI) on wheat straw decomposition and rice yield in a paddy soil, Anhui Province, East China. To do so, four treatments were selected with basal N fertilization rates of 0 (CN105), 67.5 (CN24), 97.5 (CN18), and 150 (CN12) kg ha-1. For all treatments, wheat straw and SDMI were applied at the equal rates of 6000 and 30 kg ha-1, respectively. To assess wheat straw decomposition, straw samples were taken at tillering, elongation, heading, and maturity stages of rice growth. Results indicated that straw decomposition substantially increased two to over 15 times with rice growth. In tillering stage, N amended straws had 7.5 to almost 21% higher decomposition than CN105 due to the stimulation of soil microbes with higher N requirement. After this stage, all treatments had rather similar decomposition rates. This might attribute to SDMI application that, in turn, significantly increased soil microbial respiration (P < 0.05). Generally, N addition increased grain yield 0.4–13.6% higher than CN105. This can be due the accelerated straw decomposition caused by boosting soil microbial activity/respiration. Overall, our results suggested that CN18 was the most favorable C/N ratio for both microbial straw decomposition and rice productivity in the study paddy soil. Although we found that co-application of N and SDMI is an efficient/inexpensive approach to improve soil fertility and crop productivity through acceleration of straw degradation, full documentation of straw degradation in relation to the soil properties/agricultural management practices still requires long-term field trials.

A posteriori error estimates for weak Galerkin methods for second order elliptic problems on polygonal meshes

In this paper, a posteriori error estimates for the Weak Galerkin finite element methods (WG-FEMs) for second order elliptic problems are derived in terms of an H1−equivalent energy norm. Corresponding estimators based on the helmholtz decomposition yield globally upper and locally lower bounds for the approximation errors of the WG-FEMs. Especially, the error analysis of our methods is proved to be valid for polygonal meshes (e.g., hybrid, polytopal non-convex meshes and those with hanging nodes) under general assumptions. In addition, the work can make adaptive WG-FEMs solving partial differential equations such as stokes equations and biharmonic equations on polygonal meshes possible. Finally, we verify the theoretical findings by a few numerical examples.