Prediction and optimization of a desulphurization system using CMAC neural network and genetic algorithm

In this paper, taking desulphurizing ratio and economic cost as two objectives, a ten-input two-output prediction model was structured and validated for desulphurization system. Cerebellar model articulation controller (CMAC) neural network and genetic algorithm (GA) were used for model building and optimization of cost respectively. In the model building process, the grey relation entropy analysis and uniform design method were used to screen the input variables and study the model parameters separately. Traditional regression analysis and proposed location number analysis method were adopted to analyze output errors of experiment group and predict the results of test group. Results show that regression analyses keep high fit degree with experiment group results while the fitting accuracies for test group are quite different. As for location number analysis, a power function between output errors and location numbers was fitted well with the data of experiment group and test group for SO2. Prediction model was initialized by location number analysis method. Model was validated and cost optimization case was performed with GA subsequently. The result shows that the optimal cost obtained from GA could be reduced by more than 30% compared with original optimal operating parameters under same constraints

Muscular kevlar aerogel tapes attractive to thermal insulation fabrics

Kevlar aerogel is a kind of easy-casting nano-porous material with the characteristics of low density, high porosity, low thermal conductivity, high specific surface area, etc. It can serve as functional fibers and has a bright future in the field of thermal insulation after being processed into fabrics. To improve the tensile power of aerogel fibers to bear more loads while maintaining their flexibility for further braiding, a series of Kevlar aerogel tapes were fabricated in this study by using flattened needles. It is observed that the resultant aerogel tapes show a spindle-like cross section, and have greatly improved load-bearing capability with muscular tensile strength up to 2.07 MPa. The use of a larger needle is conductive to preparing aerogel tapes that are more attractive in load-bearing, and increasing Kevlar concentration tends to result in more muscular tapes with improved breaking stress but reduced elasticity. Besides, these tapes also inherit the excellent thermal stability and char-forming ability of Kevlar, starting to decompose at around 500°C and producing carbon residue more than 40% of their initial weight at 700°C. In addition, these Kevlar aerogel tapes also perform well in terms of thermal insulation. When exposed to a hot plate of 300 °C, the fabric braided from these aerogel tapes show a considerable temperature drop per unit thickness as high as 120°C mm−1. It can be envisaged that the developed aerogel tapes with muscular tensile strength and their fabric products will be promising for high-temperature thermal insulation applications, such as being used as the insulation layer for thermal protective clothing

THE PROPERTIES AND HYDRATION OF PORTLAND CEMENT CONTAINING CALCIUM SULFOALUMINATE CEMENT

Calcium sulfoaluminate (CSA) cement has some attractive qualities, such as rapid setting, high early strength, and micro-expansion. It was commonly used to improve properties of Portland cement (PC). In this paper, the investigated results show that the setting times are notably reduced as the CSA cement content is increased. The compressive strength is slightly lower for the PC-CSA blends containing less than 10% CSA cement, but notably lower for the PC-CSA blend containing 20% CSA cement when compared to PC. High amounts of CSA cement significantly delay the hydration of alite, thereby increasing the porosity. Furthermore, the addition of CSA cement changes the ettringite morphology

Experimental investigation on the preparation and surface treatment of biomass fibers for stone mastic asphalt mixtures modification

With the sustainable development of infrastructure construction materials, the use of renewable biomass resources in asphalt mixtures could contribute to better sustainability. The bamboo fibers and corn straw fibers with lengths ranging from 1.5 to 12 mm were produced in the laboratory through the proposed crushing, steaming, and grinding processes. A surface treatment with the phenolic resin copolymer modifier was utilized to reconstruct the micro-surface of biomass fibers. The surface treatment effectively reduced the oil absorption multiplier and mass loss of proposed biomass fibers by about 0.6 and 2 %, respectively. The FI-IR absorption peak and change of micromorphology also validated the effective surface reconstructive. Afterward, the virgin asphalt (70#) mixtures and SBS-modified asphalt mixtures with/without biomass fibers were produced for road performance tests and fatigue resistance tests. The results showed that the proposed biomass fibers contributed to about 20 % to 30 % improvement in the high-temperature performance, while the low-temperature cracking resistance was also obviously increased. In addition, the moisture damage resistance and fatigue life were also improved after the addition of biomass fiber modifier, in which the residual stability and tensile strength ratio were increased by about 9 % and 6 % by comparing that with fibreless mixtures, respectively. By comparing the effect of different types and lengths of fiber modifiers, the long bamboo fiber with surface treatment represented the optimized strengthening efficiency. The enhancement mechanism of proposed biomass fiber modifiers was revealed through the microstructure observation. The feasibility of using proposed biomass fibers with surface treatment for producing high-performance SMA has been verified, which can be utilized in the field application for replacing the lignin fiber modifiers for achieving better sustainability

Preparation and characterization of magnetic α-Fe2O3/Fe3O4 heteroplasmon nanorods via the ethanol solution combustion process of ferric nitrate

An ethanol solution combustion process of ferric nitrate for preparing magnetic α -Fe _2 O _3 /Fe _3 O _4 heteroplasmon nanorods was introduced. The influencing factors, including the solvent type and the calcination conditions, were discussed. Anhydrous ethanol was considered to be the most suitable solvent for the preparation of α -Fe _2 O _3 /Fe _3 O _4 heteroplasmon nanorods, and the optimal calcination time was determined to be 2 h. By changing the calcination temperature, α -Fe _2 O _3 /Fe _3 O _4 heteroplasmon nanorods with different phase compositions could be obtained, and the mechanism was explained in detail. The results indicated that the rapid combustion method could achieve the controlled preparation of α -Fe _2 O _3 /Fe _3 O _4 heteroplasmon nanorods, which provided a general preparation approach for α -Fe _2 O _3 /Fe _3 O _4 heteroplasmon nanomaterials

Projecting Changes in Rainfall Extremes for the Huai River Basin in the Context of 1.5 °C and 2 °C Global Warming

It is indisputable that global warming has triggered more frequent extreme weather and in turn led to severe flood disasters. To understand the trend of extreme rainfall under 1.5 °C and 2 °C warming, we investigated the historical variation and future trends in extreme rainfall for the Huai River basin, which has frequently been hit by floods, using recorded meteorological data and a projection of five General Circulation Models in the Coupled Model Intercomparison Project 6. We used the years 1995–2014 as the baseline period to study the temporal and spatial changes in extreme rainfall under 1.5 °C and 2.0 °C warming scenarios. The results indicated that (1) temperatures in the Huai River basin have risen significantly from 1995 to 2014, but there are insignificant variation trends in annual precipitation (AP), intensive precipitation (R95P), maximum daily precipitation (Rx1d) and heavy rain days (Rr50) during the same time span. (2) From 2015 to 2100, both temperature and extreme rainfall indices show increase trends, with a higher rate of increase under a higher emission scenario. (3) Under the warming scenario of 1.5 °C, AP, R95P, Rx1d and Rr50 in the basin will likely increase by 4.6%, 5.7%, 6.2% and 13.4%, respectively, compared with that in the baseline period. Under the warming scenario of 2.0 °C, AP, R95P, Rx1d and Rr50 will probably increase by 7.3%, 7.4%, 10.9% and 19.0%, respectively. (4) Spatially, the changes in extreme rainfall indices under the warming scenarios of 1.5 °C and 2.0 °C generally tend to increase from north to south. Higher intensity extreme rainfall will likely extend to the whole of the Huai River basin. It is therefore essential to study adaptive measures to cope with flooding in the Huai River basin induced by the increase in future rainfall extremes

The Genome-Wide Identification of Long Non-Coding RNAs Involved in Floral Thermogenesis in Nelumbo nucifera Gaertn

The sacred lotus (Nelumbo nucifera Gaertn.) can maintain a stable floral chamber temperature when blooming, despite ambient temperature fluctuations; however, the long non-coding RNAs (lncRNAs) involved in floral thermogenesis remain unclear. In the present study, we obtain comprehensive lncRNAs expression profiles from receptacles at five developmental stages by strand-specific RNA sequencing to reveal the lncRNAs regulatory mechanism of the floral thermogenesis of N. nucifera. A total of 22,693 transcripts were identified as lncRNAs, of which approximately 44.78% had stage-specific expression patterns. Subsequently, we identified 2579 differential expressed lncRNAs (DELs) regulating 2367 protein-coding genes mainly involved in receptacle development and reproductive process. Then, lncRNAs with floral thermogenesis identified by weighted gene co-expression network analysis (WGCNA) were mainly related to sulfur metabolism and mitochondrial electron transport chains. Meanwhile, 70 lncRNAs were predicted to act as endogenous target mimics (eTMs) for 29 miRNAs and participate in the regulation of 16 floral thermogenesis-related genes. Our dual luciferase reporter assays indicated that lncRNA LTCONS_00068702 acted as eTMs for miR164a_4 to regulate the expression of TrxL2 gene. These results deepen our understanding of the regulation mechanism of floral thermogenesis by lncRNAs and accumulate data for further research

Projecting Changes in Rainfall Extremes for the Huai River Basin in the Context of 1.5 °C and 2 °C Global Warming

It is indisputable that global warming has triggered more frequent extreme weather and in turn led to severe flood disasters. To understand the trend of extreme rainfall under 1.5 °C and 2 °C warming, we investigated the historical variation and future trends in extreme rainfall for the Huai River basin, which has frequently been hit by floods, using recorded meteorological data and a projection of five General Circulation Models in the Coupled Model Intercomparison Project 6. We used the years 1995–2014 as the baseline period to study the temporal and spatial changes in extreme rainfall under 1.5 °C and 2.0 °C warming scenarios. The results indicated that (1) temperatures in the Huai River basin have risen significantly from 1995 to 2014, but there are insignificant variation trends in annual precipitation (AP), intensive precipitation (R95P), maximum daily precipitation (Rx1d) and heavy rain days (Rr50) during the same time span. (2) From 2015 to 2100, both temperature and extreme rainfall indices show increase trends, with a higher rate of increase under a higher emission scenario. (3) Under the warming scenario of 1.5 °C, AP, R95P, Rx1d and Rr50 in the basin will likely increase by 4.6%, 5.7%, 6.2% and 13.4%, respectively, compared with that in the baseline period. Under the warming scenario of 2.0 °C, AP, R95P, Rx1d and Rr50 will probably increase by 7.3%, 7.4%, 10.9% and 19.0%, respectively. (4) Spatially, the changes in extreme rainfall indices under the warming scenarios of 1.5 °C and 2.0 °C generally tend to increase from north to south. Higher intensity extreme rainfall will likely extend to the whole of the Huai River basin. It is therefore essential to study adaptive measures to cope with flooding in the Huai River basin induced by the increase in future rainfall extremes