•Thermal modification does not significantly change the ballistic performance of coastal western hemlock CLT.•Density and hardness do no fully encompass the energy absorbing capacity of CLT under ...small arms ballistic threats.•Empirically fit UFC partial penetration equation formulations fit treatment specific datasets with minimal error.•One global UFC partial penetration equation can be utilized for design with an appropriate safety factor.
To test and understand the potential for integration of thermally modified coastal western hemlock CLT systems in military applications, 109 ballistic experiments were conducted at the United States Army Engineer Research Development Center's Fragmentation Simulation Facility. For a range of CLT thicknesses, the depth of penetration and residual velocities were recorded for different striking velocities utilizing a 0.50 caliber steel sphere projectile. This information was used to compare and add to the existing ballistics data for CLT, investigate the effects of thermal modification on high strain rate loading of wood, assess physics-based empirical design equations used by the Unified Facilities Criteria, and evaluate energy absorbing behavior at a range of thicknesses and striking velocities.
The experimental results showed that thermal modification does not significantly alter the full and partial penetration performance of coastal western hemlock CLT. However, the mechanism of fracture along the path of the projectile differed, which indicates that the model parameters used in the UFC design equation (density, hardness, and projectile properties) may not fully encompass the ballistic failure mechanisms of CLT.
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•Thermal modification method was used for original copper slag.•Phase transformation of raw copper slag can be favorable for NOx removal.•The active components for NOx removal in ...modified copper slag was illustrated.•The possible reaction pathway of simultaneous removal of SO2 and NOx was proposed.
The high desulfurization capacity has been obtained in the wet process when using industrial waste solids as novel absorbents, however, the high-efficient NOx removal remains as a challenge. Here we report a novel wet method with highly active slurry containing CaO-thermally modified copper slag and KMnO4 oxidant to remove NOx and SO2 simultaneously. We demonstrate a best removal efficiency of 84.4% and 100% for NOx and SO2, respectively. The enhanced efficiency was achieved with 30 wt% CaO and calcinated at 800 °C for 200 min. Interestingly, the NOx removal efficiency was primarily depending on calcination temperature, while CaO dosage and calcination time had an insignificant influence. The increasing NOx removal efficiency could be attributed to the optimized phase structure of copper slag and the higher alkalinity of the slurry. Specifically, the phase structure of the original copper slag was effectively converted by CaO calcination, resulting in a decrease in the contents of Fe(II)-containing substances including Fe3O4, Fe2SiO4, and metal sulfides. Through composition simulation experiments with raw copper slag, Fe2O3, CuFe2O4, and CuO in the modified equivalent were identified to be responsible for the NOx removal. On the contrary, Ca3Fe2(SiO4)3 formed at higher calcination temperatures was detrimental to NOx removal efficiency. With characterizing the modified copper slag samples via XRD before and after reaction along with analyzing the spent solution with ion chromatography (IC), we proposed a corresponding reaction mechanism of simultaneous removal of NOx and SO2.
•Thermal modified phosphogypsum (MPG) was used as a substitute for calcium sulphoaluminate cement (CSC).•The effects of MPG content and temperature on the engineering properties and micro-mechanism ...of CSC were studied.•The optimal replacement of 10% 300℃ MPG can effectively improve the strength enhance of CSC.•Calcium sulfate hemihydrate in MPG enhances the characteristics of fast setting and early strength for CSC.
The phosphogypsum (PG) can be used as a substitute for calcium sulphoaluminate cement (CSC) due to its high content of calcium sulfate dehydrate. In this study, the engineering properties including setting time, compressive strength and fluidity index of CSC with addition of thermal modified phosphogysum (MPG) were experimentally investigated. Furthermore, the micro-mechanisms including crystalline phase and microstructure evolutions of CSC incorporating MPG under different thermal treatment temperatures were analyzed via conducting X-ray diffraction (XRD), heat of hydration, thermogravimetry (TG) and scanning electron microscopy (SEM) tests. The results show that the optimum PG content and thermal modification temperature were respectively 10% and 300℃, which achieved the maximum compressive strength of 41.59 MPa. The hydration heat release peak of CSC with 300℃ MPG was advanced, contributing to shorter setting time and poor fluidity of CSC. Whereas after incorporating untreated and 100℃ MPG, the hydration exothermic peak of CSC lagged behind, causing higher retarding effect and better fluidity. The main hydration products of ettringite (AFt) and alumina gel (AH3) in CSC-MPG mixture were respectively produced in the early and later stages, which were similar to that in pure CSC. The amount of AFt was the most under the optimum incorporation of 10% MPG at 300℃, which was mainly responsible for the highest structure density. The key findings in this study can achieve the double benefits of utilizing waste PG and improving the engineering properties of CSC.
Disposal of coal gasification fine slag (CGFS) has caused environmental pollution and resource waste. Its decarbonization is the bottleneck of aluminum and silicon resource utilization. A ...fluidization-melting combustion system is proposed in this study to realize the decarbonization. The fluidized thermal modification and burnout characters of residual carbon in CGFS were investigated experimentally on a bench-scale test rig. A two-stage decarburization path of CGFS was concluded and verified. The fluidized modification of CGFS is first conducted to decrease the particle size and improve the specific surface area and combustion reactivity. So, the modified exposed carbon in CGFS rapidly burns in the melting furnace to generate the condition above the fluid temperature of minerals. Then the mineral shell of the amorphous mineral covered carbon in CGFS is molten and damaged, and the carbon appears and burns out. The decrease in the thermal modification temperature induced deceases in melting combustion temperature and decarbonization efficiency. Efficient decarbonization of CGFS produced by three different entrained bed gasifiers was realized by the fluidization-melting combustion, the decarburization efficiencies are all above 95% and the comprehensive carbon contents of ash and slag are all below 5%.
•Treatment of gasification fine slag by a fluidization-melting combustion system.•A two-stage decarburization path of gasification fine slag is concluded.•The combustion reactivity is improved through the fluidized thermal modification.•Mineral shell is damaged and residual carbon burns out during melting combustion.•Efficient decarbonization of three kinds of gasification fine slag is verified.
Thermal modification was simply performed on molybdenite to enhance the adsorption of Pb(II) in aqueous solutions, and the root of this phenomenon was well studied in this work. Various thermal ...modification temperatures at 300 °C, 400 °C and 500 °C were applied to modify the surface property of molybdenite, producing different degrees of edge defect and surface wettability in molybdenite samples. Contact angle tests, atomic force microscopy (AFM) observations and adsorption tests illustrated that molybdenite thermally modified at 400 °C contained most edge defects and achieved a 147.846 mg/g Pb(II) adsorption, which was almost 10 times of that obtained by natural molybdenite. The adsorption experiment also indicated that the increase of surface hydrophilia of molybdenite would slightly benefit the Pb(II) adsorption. The X-ray photoelectron spectroscope (XPS) exhibited that a strong chemical adsorption existed between Pb(II) and S elements. AFM study further demonstrated that the interaction between Pb(II) and S atoms exposed at the triangular edges of molybdenite were the intrinsic reason for the great enhancement of Pb(II) adsorption. This work provides a new insight to absorb Pb(II) in aqueous solutions using natural molybdenite.
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•M-400 achieved 147.8 mg/g Pb (II) adsorption in aqueous solutions.•Thermal modification enabled molybdenite with a 10 times enhancement on Pb (II) adsorption compared with natural molybdenite.•Sulfur vacancies on edges had strong affinity to Pb ions.
•Beech wood torrefaction at different conditions using comprehensive instrumentation.•Heat treatment heterogeneity can be assessed by water vapour sorption measurements.•The data-set allowed a ...complete computational code to be validated.•Torrefaction schedule should be adapted to the particle size and its initial MC.•Treatment conditions meeting users’ expectations found by probabilistic optimization.
This paper uses a comprehensive computational model to propose optimal wood torrefaction conditions by probabilistic optimization. Its main outcome is to propose tailor-made heat treatment conditions (temperature levels-duration of mild pyrolysis at temperature levels ranging from 200 to 300 °C) to meet users’ expectations in terms of overall mass loss, duration and homogeneity of treatment. To this purpose, beech wood boards were torrefied with a usual 3-steps treatment schedule (drying, heating and cooling) under contrasting configurations in a well-instrumented device. The heterogeneity of the treatment within the wood sample was assessed through X-ray attenuation profile and water vapour sorption isotherm. These results allowed the model to be validated. In particular, it predicts the evolution of the mass loss and internal temperatures with good accuracy, including the temperature overshot. The results highlight the need to adjust the heat treatment schedule to each input parameter such as the wood piece dimensions and its initial moisture content or density, in order to limit the effect of exothermic reactions. The torrefaction model was then embedded in a probabilistic optimization process. A case study demonstrates the ability of the model to propose an alternative 3-steps treatment schedule able to reach the target mass loss while controlling the temperature overshot within the wood piece.
Abstract
In recent years, researchers have been exploring alternative sources of starch for drug delivery. Traditional options like corn, potato, and rice starches have been widely used, but ...sustainability concerns have prompted the investigation of nonconventional starches. Elephant foot yam starch, derived from an agricultural polymer, has gained popularity due to its wide availability. Starches are fundamentally unsuited for the majority of applications; they must be physically and/or chemically altered to maximize their advantages and/or minimize their drawbacks. Due to the chemical toxicity, starch modification is often done using physical techniques that are inexpensive. This study aims to evaluate the impact of elephant foot yam starch on the physicochemical properties and drug delivery of potato starch. Pregelatinization, a crucial process, is found to increase amylose content and improves starch flow properties, as confirmed by Fourier‐transform infrared spectroscopy analysis showing gelatinization in the mixture. Field emission scanning electron microscopy images reveal complete disruption of the starch granular structure after modification. Tablets made with a mixture of pregelatinized starches exhibit a slower drug release compared to those with pregelatinized starch alone. Notably, inclusion of potato starch in the mixture results in a more sustained drug release. Hence, modified starches have diverse applications for enhancing solubility of poorly soluble drugs.
Thermal modification has been commonly perceived to improve wood dimensional stability, but decreases certain main mechanical properties. This research aimed to optimize thermal modification for ...poplar wood to determine its impacts on strength class for potential structural use. In this study, poplar wood was thermally modified at temperatures between 160 and 210 °C and 2 h duration, after which the chemical composition and mechanical properties were determined. The results showed thermal modification led to hemicelluloses degradation, which served as the main reason for strength reduction. The main mechanical properties of thermally-modified wood decreased with temperatures, except for compressive strength and modulus of elasticity, which increased with temperature (≤180 °C) and was followed by a reduction at ≥190 °C. The strength class of thermally-modified wood was dependent on the smaller value of modulus of elasticity and shear strength. Thermal modification at 180 °C was shown to be practical in improving wood properties for structural use.
•The cause of variations in heated poplar's strength was discovered.•Strength class of heated poplar at high temperatures was determined.•A suitable modification temperature was recommended in view of structural use.
In this study, the combined effects of chemical (with tricine and bicine) and thermal treatments were investigated. The modifications which appeared in the wood structure were evaluated by infrared ...spectroscopy and chemometric methods (principal component analysis and hierarchical cluster analysis). After the treatment, about 6–7% of WPG was identified in treated samples, but further thermal treatment decreased the WPG to about 5%. The modifications appearing in the spectra were mostly related to increase of the intensities of the bands assigned to CO groups but also to N–H and C–N groups, with shifting of some bands to higher wavenumber values.
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•The combined effects of chemical and thermal treatment on soft and hardwood were evaluated.•The effectiveness of treatment was evaluated by infrared spectroscopy and chemometric methods.•The occurrence of the reactions between the functional groups from bicine and tricine and wood structure were identified.•Softwood samples were more susceptible to chemical/thermal modification than the hardwood samples.
