•An electromagnetic harvester is designed for harvesting energy from human motion.•Structural parameter and magnetic field are analyzed for performance enhancement.•Dynamic model is established for ...theoretical analysis under different excitations.•Experimental results verify the effectiveness of the proposed device.•Proper structural parameters can improve the harvester’s performance.
A tunable magnetic-spring based electromagnetic energy harvester is presented in this paper to harvest vibration energy from human motions. The harvester is modeled by Ansoft Maxwell software and the best way of magnetic stack is chosen according to the generated voltage from simulation. Dynamic model of the energy harvester is derived and corresponding theoretical and numerical analysis are performed to evaluate the performance of the proposed system. Experimental results under frequency-sweep excitation with different acceleration levels show that the harvester is promising to generate electricity for a broadband frequency range. In the experiments considering human motion, the impact between shoe and ground as well as the swing motion of leg are investigated by attaching the device to human lower-limb. Testing results under various motion speeds show that proper structural parameters such as equivalent mass and movement length can improve the performance of the harvester. Moreover, it is demonstrated that the swing motion of human lower-limb could enhance the performance of the proposed device, especially for higher motion speed.
The development of biofuels has been considered as an important countermeasure to abate anthropogenic CO2 emissions, suppress deteriorated atmospheric greenhouse effect, and mitigate global warming. ...To produce biofuels from biomass, thermochemical conversion processes are considered as the most efficient routes wherein torrefaction has the lowest global warming potential. Combustion is the easiest way to consume biomass, which can be burned alone or co-fired with coal to generate heat and power. However, solid biomass fuels are not commonly applied in the industry due to their characteristics of hygroscopic nature and high moisture content, low bulk density and calorific value, poor grindability, low compositional homogeneity, and lower resistance against biological degradation. In recently developing biomass conversion technologies, torrefaction has attracted much attention since it can effectively upgrade solid biomass and produce coal-like fuel. Torrefaction is categorized into dry and wet torrefaction; the former can further be split into non-oxidative and oxidative torrefaction. Despite numerous methods developed, non-oxidative torrefaction, normally termed torrefaction, has a higher potential for practical applications and commercialization when compared to other methods. To provide a comprehensive review of the progress in biomass torrefaction technologies, this study aims to perform an in-depth literature survey of torrefaction principles, processes, systems, and to identify a current trend in practical torrefaction development and environmental performance. Moreover, the encountered challenges and perspectives from torrefaction development are underlined. This state-of-the-art review is conducive to the production and applications of biochar for resource utilization and environmental sustainability. To date, several kinds of reactors have been developed, while there is still no obviously preferred one as they simultaneously have pros and cons. Integrating torrefaction with other processes such as co-firing, gasification, pyrolysis, and ironmaking, etc., makes it more efficient and economically feasible in contrast to using a single process. By virtue of capturing carbon dioxide during the growth stage of biomass, negative carbon emissions can even be achieved from torrefied biomass.
Epithelial-mesenchymal transition (EMT)/mesenchymal-epithelial transition (MET) processes are proposed to be a driving force of cancer metastasis. By studying metastasis in bone marrow-derived ...mesenchymal stem cell (BM-MSC)-driven lung cancer models, microarray time-series data analysis by systems biology approaches revealed BM-MSC-induced signaling triggers early dissemination of CD133
/CD83
cancer stem cells (CSCs) from primary sites shortly after STAT3 activation but promotes proliferation towards secondary sites. The switch from migration to proliferation was regulated by BM-MSC-secreted LIF and activated LIFR/p-ERK/pS727-STAT3 signaling to promote early disseminated cancer cells MET and premetastatic niche formation. Then, tumor-tropic BM-MSCs circulated to primary sites and triggered CD151
/CD38
cells acquiring EMT-associated CSC properties through IL6R/pY705-STAT3 signaling to promote tumor initiation and were also attracted by and migrated towards the premetastatic niche. In summary, STAT3 phosphorylation at tyrosine 705 and serine 727 differentially regulates the EMT-MET switch within the distinct molecular subtypes of CSCs to complete the metastatic process.
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•Catalytic effects of potassium on biomass thermochemical reactions are studied.•Crystallinity of cellulose decreases with increasing potassium concentration.•Reactivity of biomass ...impregnate by potassium in pyrolysis is intensified.•Ignition temperature of treated biomass is lowered slightly, whereas its burnout temperature is reduced profoundly.•Substantial time saving can be achieved for potassium-impregnated biomass in torrefaction.
Potassium is a natural catalyst in biomass thermochemical conversion and plays an essential role in plant’s growth. To figure out the catalytic effects of potassium on the thermochemical behaviors of biomass, the pyrolysis, combustion, and torrefaction characteristics of rubber wood are comprehensively studied using a thermogravimetric analyzer where the biomass is impregnated by potassium carbonate (K2CO3) at different concentrations. The impregnated potassium is clearly exhibited in the spectra of Fourier-transform infrared spectroscopy, while X-ray diffraction indicate that the cellulose crystallinity decreases with increasing the potassium concentration which increases the biomass reactivity in pyrolysis. The ignition temperature of the potassium-impregnated biomass is lowered slightly when compared with the raw biomass; alternatively, its burnout temperature is reduced profoundly, suggesting that the addition of potassium into the biomass can substantially intensify its oxidative reactivity. Considering the treated biomass torrefaction, its cellulose decomposition at 250 °C is intensified, rendering a reduction in the solid yield with increasing potassium concentration. With the same mass loss at 200–300 °C, at least 28% of torrefaction time can be saved for the potassium-impregnated biomass. Accordingly, the catalytic effect of potassium on biomass thermochemical conversion is clearly outlined. Moreover, the produced potassium-rich biochar is conducive to the developments of carbon storage, soil amendment, and negative emissions technologies.
Autoimmune thyroid disease (AITD), including Graves disease (GD) and Hashimoto disease (HD), is an organ-specific autoimmune disease with a strong genetic component. Although the cytotoxic ...T-lymphocyte-associated protein 4 (CTLA4) polymorphism has been reported to be associated with AITD in adults, few studies have focused on children. The aim of our study was to investigate whether the CTLA4 polymorphisms, including -318C/T (rs5742909), +49A/G (rs231775), and CT60 (rs3087243), were associated with GD and HD in Han Chinese adults and children. We studied 289 adult GD, 265 pediatric GD, 229 pediatric HD patients, and 1058 healthy controls and then compared genotype, allele, carrier, and haplotype frequencies between patients and controls. We found that CTLA4 SNPs +49A/G and CT60 were associated with GD in adults and children. Allele G of +49A/G was significantly associated with GD in adults (odds ratio OR, 1.50; 95% confidence interval CI, 1.21-1.84; corrected P value Pc < 0.001) and children (OR, 1.42; 95% CI, 1.15-1.77; Pc = 0.002). Allele G of CT60 also significantly increased risk of GD in adults (OR, 1.63; 95% CI, 1.27-2.09; Pc < 0.001) and GD in children (OR, 1.58; 95% CI, 1.22-2.04; Pc < 0.001). Significant linkage disequilibrium was found between +49A/G and CT60 in GD and control subjects (D' = 0.92). Our results showed that CTLA4 was associated with both GD and HD and played an equivalent role in both adult and pediatric GD in Han Chinese population.
One-dimensional cobalt sulfide (CoS) acicular nanorod arrays (ANRAs) were obtained on a fluorine-doped tin oxide (FTO) substrate by a two-step approach. First, Co3O4 ANRAs were synthesized, and then ...they were converted to CoS ANRAs for various periods. The compositions of the films obtained after various conversion periods were verified by X-ray diffraction, UV–visible spectrophotometry, and X-ray photoelectron spectroscopy; their morphologies were examined at different periods by scanning electron microscopic and transmission electron microscopic images. Electrocatalytic abilities of the films toward I–/I3 – were verified through cyclic voltammetry (CV) and Tafel polarization curves. Long-term stability of the films in I–/I3 – electrolyte was studied by CV. The FTO substrates with CoS ANRAs were used as the counter electrodes for dye-sensitized solar cells; a maximum power conversion efficiency of 7.67% was achieved for a cell with CoS ANRAs, under 100 mW/cm2, which is nearly the same as that of a cell with a sputtered Pt counter electrode (7.70%). Electrochemical impedance spectroscopy was used to substantiate the photovoltaic parameters.
•Thermochemical conversion technologies using microalgae as feedstocks are reviewed.•The progress of torrefaction for solid biofuels is introduced.•Liquefaction and pyrolysis techniques for producing ...bio-oils are illustrated.•Gasification routes to produce combustible gases are outlined.•Detailed conversion processes and their outcome are addressed.
Following first-generation and second-generation biofuels produced from food and non-food crops, respectively, algal biomass has become an important feedstock for the production of third-generation biofuels. Microalgal biomass is characterized by rapid growth and high carbon fixing efficiency when they grow. On account of potential of mass production and greenhouse gas uptake, microalgae are promising feedstocks for biofuels development. Thermochemical conversion is an effective process for biofuel production from biomass. The technology mainly includes torrefaction, liquefaction, pyrolysis, and gasification. Through these conversion technologies, solid, liquid, and gaseous biofuels are produced from microalgae for heat and power generation. The liquid bio-oils can further be upgraded for chemicals, while the synthesis gas can be synthesized into liquid fuels. This paper aims to provide a state-of-the-art review of the thermochemical conversion technologies of microalgal biomass into fuels. Detailed conversion processes and their outcome are also addressed.
► Raw Cryptomeria japonica is torrefied at 250 and 300°C for 1h. ► Raw/torrefied Cryptomeria japonica are blended with an anthracite coal. ► A thermogravimetric analyzer is used to examine the ...co-pyrolysis characteristics. ► Five different biomass blending ratios of 100, 75, 50, 25, and 0wt.% are considered. ► Interactions or synergistic effects between raw/torrefied biomass and coal are slight.
The properties of biomass can be improved via torrefaction, and torrefied wood is a fuel with the potential to partially replace coal. In this study, raw Cryptomeria japonica (WRaw) is torrefied at 250 (TW250) and 300°C (TW300) for 1h, and then mixed with an anthracite coal to undergo co-pyrolysis. A thermogravimetric analyzer is used to examine the co-pyrolysis characteristics of fuel blends and five different biomass blending ratios (BBRs) of 100, 75, 50, 25, and 0wt.% are taken into consideration. When WRaw, TW250, and the coal are tested, the pyrolysis is characterized by a three-stage reaction, whereas four-stage thermal degradation is found for TW300 and fuel blends. The predictions from the linear superposition of the thermal decomposition of individual fuels fit the experimental data of the fuel blends, suggesting that the interaction or synergistic effect of co-pyrolysis between the raw/torrefied C. japonica and the coal is slight. The co-pyrolysis kinetics of the fuel blends is also analyzed. The variation of chemical kinetics with decreasing BBR in the second stage is different from that in the third stage. That is, an increase in BBR leads to an increase in the activation energy in the second stage, whereas it causes a decrease in the third stage. This is attributed to that the reactivities of cellulose and lignin in biomass are different from that of coal in the two stages.
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•Color change and hygroscopic transformation of poplar and fir from torrefaction are analyzed.•Total color difference linearly increases with increasing mass loss or torrefaction ...severity.•Hygroscopic transformation of biomass is evaluated by equilibrium moisture content (EMC) and contact angle.•Hygroscopicity reduction extent (HRE) can reach up to 57.39% at 230 °C.•Carbon, hydrogen, and oxygen removals from torrefaction can be predicted by color change and HRE.
Biochar is a potential medium for carbon storage, so its production and storage have been considered as is a crucial route to effectively achieve negative CO2 emissions. Meanwhile, torrefaction is a thermochemical conversion process for producing biochar. Biochar is featured by its hydrophobicity, which makes it different from its parent biomass with hygroscopicity and is conducive to material storage. To evaluate the hygroscopic transformation of biomass from torrefaction, two woody biomass materials of poplar (hardwood) and fir (softwood) are torrefied at temperatures of 200–230 °C, and the variations of color, equilibrium moisture content, and contact angle of raw and torrefied samples are examined. The results indicate that the total color difference of torrefied woods increases linearly with increasing mass loss. The hygroscopicity reduction extent in torrefied fir is higher than in torrefied poplar, and can be increased by up to 57.39% at 230 °C. The tests of the contact angle suggest that the hygroscopicity of the raw woods is evidently exhibited, whereas the angles of the torrefied woods are in the range of 94–113°, showing their hydrophobic surfaces (>90°). The decarbonization, dehydrogenation, and deoxygenation phenomena of the biomass during torrefaction are also analyzed. It is found that the three indexes can be correlated well by the total color difference and hygroscopicity reduction extent. A comprehensive study on the improvement of hydrophobicity of produced biochar has been performed, which clearly shows the potential of carbon storage and negative CO2 emissions by biochar.
This study aims to investigate the adsorption behavior of cationic and anionic dyes of methylene blue (MB) and Congo red (CR) onto wet-torrefied Chlorella sp. microalgal biochar respectively, as an ...approach to generate a waste-derived and low-cost adsorbent. The wet-torrefied microalgal biochar possessed microporous properties with pore diameter less than 2 nm. The optimum adsorbent dosage of wet-torrefied microalgal biochar for MB and CR dyes removal were determined at 1 g/L and 2 g/L, respectively, with their natural pHs as the optimum adsorption pHs. The determined equilibrium contact times for MB and CR were 120 h and 4 h, respectively. Based on the equilibrium modeling, the results revealed that Langmuir isotherm showed the best model fit, based on the highest R2 coefficient, for both the adsorption processes of MB and CR using the wet-torrefied microalgal biochar, indicating that the monolayer adsorption was the dominant process. From the modeling, the maximum adsorption capacities for MB and CR were 113.00 mg/g and 164.35 mg/g, respectively. The kinetic modeling indicated the adsorption rate and mechanism of the dyes adsorption processes, which could be crucial for future modeling and application of wet-torrefied microalgal biochar. From the results, it suggests that the valorization of microalgae by utilizing wet-torrefied microalgal biochar as the effective adsorbent for the removal of toxic dyes with an approach of microalgal biorefinery and value-added application to the environment is feasible.
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•Wet-torrefied Chlorella sp. GD microalgal biochar serves as a microporous adsorbent.•Optimum pHs for adsorption of MB and CR are at their natural pH conditions.•Optimum adsorbent dosage for MB is 1 g/L and CR is 2 g/L.•The maximum adsorption capacity for MB is 113.00 mg/g and CR is 164.35 mg/g.•Langmuir isotherm shows the best model fit on microalgal biochar dyes adsorption.
The main finding of the work: The adsorption of dye removal using microalgal biochar derived from the wet-torrefaction conversion process is addressed which is conducive to wastewater treatment.
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