Flat micro heat pipe-based shell and tube storage unit for indirect solar dryer: a pilot study.

Poria cocos has been dried in an indirect solar drying system composed of a roughened solar air heater (RSAH), a shell and tube storage unit assisted with flat micro heat pipes fins, and a drying chamber. The main novelty in this study is using FMHPs as fins in shell and tube storage unit with paraffin wax and lack of investigations on Poria cocos solar drying as medicinal material used in Chinese medicine. First and second laws of thermodynamics are used to assess the performance of the system and the results indicated that the RSAH average thermal ([Formula: see text]) and exergy efficiency ([Formula: see text]) were 73.9% and 5.1%, respectively, with averaged incident solar radiation of 671 W/m2 under airflow rate of 0.0381 m3/s. Furthermore, the storing system showed 37.6% as averaged overall [Formula: see text] and 17.2% as averaged overall [Formula: see text], as well as, discharging prolonged to 4 h with effective drying temperature. The overall [Formula: see text] of the dryer was 27.6% with specific energy consumption (SEC) of 8.629 kWh/kg moisture. The payback period of the system is 1.7 years.

Catalytic mechanism of N-containing biochar on volatile-biochar interaction for the same origin pyrolysis.

Nitrogen, as a common element, is widely present in biomass. The effects of nitrogenous substances on the same origin pyrolysis of biomass and the consequences of N-containing biochar on the catalytic process of volatiles are important for further analyzing the pyrolysis mechanism of biomass. In this research, N-containing biochar was prepared under different conditions, and the interaction between N-containing biochar and biomass pyrolysis volatiles at 400-700 °C was studied. The results show that N-containing biochar can simultaneously participate in reactions as adsorbents, catalysts, and reactants. Its catalytic effect is obviously different for various N configurations. Pyridinic N and pyrrolic N can promote the cracking of lignin into methoxy phenol compounds and promote the further cracking of 5-hydroxymethylfurfural. Graphitic N and oxidized N can promote the further decomposition of phenol and the conversion of D-xylose into small-molecule ketones. In addition, oxidized N can also inhibit the cracking of lignin to produce guaiacol. In the long-term interaction, the highly active pyridinic N tends to convert to a more stable graphitic N.

The potential for biochar application in "Shatangju" (Citrus reticulate cv.) orchard on acid red soil: Biochar prepared from its organic waste in an orchard.

Carbonization of agricultural and forestry wastes is the main use of biochar application in agriculture. In this study, the effects of biochar on the physical and chemical properties of soil and diversity in rhizosphere microorganisms, leaf nutrients and fruit quality of acid red soil in "Shatangju" (Citrus reticulate cv.) orchard were studied using organic wastes and small-scale carbonization furnaces from orchards were used to produce biochar. The results showed that the finished rate of biochar produced from the organic wastes in the orchard was approximately 37%, and the carbon content of the finished product was as high as 80%. The results suggested that the biochar produced in the orchard could meet the annual consumption of the orchard. Applying biochar can improve the physical and chemical properties of acid soil in the "Shatangju" orchard by enhancing the availability of various mineral nutrients such as nitrogen, phosphorus, potassium, calcium, magnesium and boron. The species and quantity of root and rhizosphere microbial communities (fungi, bacteria and archaea) increased, and the dominant bacterial group changed, manifested in the increase in microbial diversity. Biochar directly affected the soil pH value and increased the soil organic carbon content, which may be the main reason for the change in microbial diversity in the soil and rhizosphere of "Shatangju" in the orchard and pot tests. The fruit quality of each treatment group with biochar was also better than that of the control group and improved fruit coloring. In the pure soil test, whether or not chemical fertilizer was applied, 3% biochar amendments can provide a suitable pH value for "Shatangju" growth and are relatively stable. Regardless of whether or not fertilizer was applied, 1.5%-3% biochar improved the soil in the pot test. In the field, the biochar at a rate of 2.4 kg/plant to 3.6 kg/plant, respectively, was the best in improving soil physical and chemical properties, foliar nutrition and fruit quality. Therefore, the amount of biochar added in the open environment (if the garden) can be slightly adjusted according to the results of the closed environment test (pure soil test and pot test). In this experiment, we explored the self-recycling of organic carbon, mainly through the preparation of a simple small-scale biochar furnace suitable for the use by orchards, and selected the appropriate amount of biochar to improve the physical and chemical conditions of "Shatangju" orchard soil and increase fruit quality.

Mechanical Properties and Degradation Behaviors of Zn-xMg Alloy Fine Wires for Biomedical Applications.

Zn and Zn-based alloys exhibit biosafety and biodegradation, considered as candidates for biomedical implants. Zn-0.02 wt.% Mg (Zn-0.02 Mg), Zn-0.05 wt.% Mg (Zn-0.05 Mg), and Zn-0.2 wt.% Mg (Zn-0.2 Mg) wires (Φ 0.3 mm) were prepared for precision biomedical devices in this work. With the addition of Mg in Zn-xMg alloys, the grain size decreased along with the occurrence of Mg2Zn11 at the grain boundaries. Hot extrusion, cold drawing, and annealing treatment were introduced to further refining the grain size. Besides, the hot extrusion and cold drawing improved the tensile strength of Zn-xMg alloys to 240-270 MPa while elongation also increased but remained under 10%. Annealing treatment could improve the elongation of Zn alloys to 12% -28%, but decrease the tensile strength. Furthermore, Zn-xMg wires displayed an increase in degradation rate with Mg addition. The findings might provide a potential possibility of Zn-xMg alloy wires for biomedical applications.

Catalytic characteristics of a Ni-MgO/HZSM-5 catalyst for steam reforming of toluene.

Steam reforming is a potential technology for the conversion of biomass pyrolysis tar into gaseous products. In this study, HZSM-5 was selected as the nickel-based catalyst support and toluene was chosen as the tar model compound. Ni was replaced with MgO to improve the coking resistance of the catalyst. The effects of Ni and MgO loading on toluene conversion and gaseous product generation rate were investigated. The low Ni-loading Ni/HZSM-5 catalyst exhibited poor catalytic activity, whereas a high Ni-loading catalyst displayed poor coking resistance. The addition of the MgO promoter enhanced the steam reforming performance of the Ni/HZSM-5 catalyst with a low loading of active metal Ni (3 wt%). The optimal MgO loading was found at 6 wt%. By characterizing the catalyst before and after the reaction, we found that MgO would enter the wall and pores of the support, resulting in increased pore size and decreased specific surface area. Ni and MgO were combined to form NiO-MgO solid solution active centers, which enhanced the catalytic reforming performance. Moreover, more MgO loading increased the alkaline strength of the catalytic surface, enhanced the adsorption of CO2, and improved the resistance to carbon deposition. This study revealed the feasibility of replacing Ni with MgO and the potential mechanism of maintaining similar catalytic performance. This study also laid the theoretical foundation for the industrial application of nickel-based catalysts.

Biomass briquetting reduces the energy loss during long-term ensiling and enhances anaerobic digestion: A case study on rice straw.

The present study evaluated the impact of briquetting prior to ensiling on rice straw characteristics and anaerobic digestion performance. Ensiling for 10 months significantly reduced cellulose, hemicellulose and lignin of the uncompressed straw by 50.3%, 61.6% and 34.6%, respectively. However, increase of briquetting ratio enhanced the cellulose and hemicellulose contents at different ensiling times. In addition, increasing of ensiling time significantly reduced the biogas yield, while the highest cumulative biogas yield of 313.8 L kg-1 VS was obtained from rice straw ensiled for 7 days at 1:6 briquetting ratio. Interestingly, the maximum biogas productivity of 1:6 briquetted straw after 10 months ensiling was 17.7% higher than that of the uncompressed straw ensiled for 7 days. Thus, briquetting prior to ensiling is a favorable approach to reduce the mass loss for enhanced biogas yield and energy recovery.