Adsorption of pyrolysis oil model compound (phenol) with plasma-modified hydro-chars and mechanism exploration.

Phenol is one of the important ingredients of pyrolysis oil, contributing to the high biotoxicity of pyrolysis oil. To promote the degradation and conversion of phenol during anaerobic digestion, cheap hydro-chars with high phenol adsorption capacity were produced. The phenol adsorption capabilities of the plain hydro-char, plasma modified hydro-char at 25 °C (HC-NH3-P-25) and 500 °C (HC-NH3-P-500) were evaluated, and their adsorption kinetics and thermodynamics were explored. Experimental results indicate that the phenol adsorption capability of HC-NH3-P-500 was the highest. The phenol adsorption kinetics of all samples followed the pseudo-second-order equation and interparticle diffusion model, indicating that the adsorption rate of phenol was controlled by interparticle diffusion and chemistry adsorption simultaneously. By DFT calculations, π-π stacking and hydrogen bond are the main interactions for phenol adsorption. It was observed that an enriched graphite N content decreased the average vertical distance between hydro-chars and phenol in π-π stacking complex, from 3.5120 to 3.4532 Å, causing an increase in the negative adsorption energy between phenol and hydro-char from 13.9330 to 23.4181 kJ/mol. For hydrogen bond complex, the average vertical distance decreased from 3.4885 to 3.3386 Å due to the increase in graphite N content; causing the corresponding negative adsorption energy increased from 19.0233 to 19.9517 kJ/mol. Additionally, the presence of graphite N in the hydro-char created a positive diffusion region and enhanced the electron density between hydro-char and phenol. Analyses suggest that enriched graphite N contributed to the adsorption complex stability, resulting in an improved phenol adsorption capacity.

MSW pyrolysis volatiles' reforming by incineration fly ash for both pyrolysis products upgrading and fly ash stabilization.

The effective disposal of municipal solid wastes (MSW) and its incineration-derived fly ash (IFA), which contains large amounts of heavy metals (HMs) and chlorine (Cl), is an urgent task. In this study, IFA was used to reform MSW pyrolysis volatiles within 500-800 °C. The changes of reformed pyrolysis products, the migration characteristics of HMs and Cl between IFA and pyrolysis products were investigated. The results indicated that the O- and Cl-containing compounds in pyrolysis oil tended to decrease, light hydrocarbons and its calorific value increased accordingly after reforming; more CH4 and H2 gases were produced concurrently. The increase in reforming temperature enhanced these trends. The IFA absorbed Cl from volatiles during reforming, which reduced HCl in the gas product. The toxicity equivalent (TEQ) of PCDD/Fs in IFA decreased dramatically from 0.47 µg/kg to 0.0055 µg/kg after reforming at 500 °C, and it decreased with increasing reforming temperature. Some of the HMs' concentrations in the used IFAs increased, but their leaching capacity all decreased significantly at 800 °C except for Cr. The used IFA at 800 °C (IFA-800) corresponded to the lowest HMs leaching concentrations and could meet the landfill requirements; while the used IFA at 500 °C (IFA-500) corresponded to the maximum carbon deposition of 14.63 wt%, providing the energy source for its melting. Therefore 800 °C was recommended for harmless disposal of IFA, and 500 °C was better for a further melting of IFA., The contamination of pyrolysis liquid caused by inorganic Cl-containing compounds at 500 and 800 °C with much lower levels than the original. This study showed the hazardous properties of IFA can be dampened after interacting with MSW pyrolysis volatiles within the tested temperature range, and provided a good chance for the simultaneous disposal of IFA and recovery of high-quality MSW pyrolysis products.

Biomimetic folding of triangular deployable membranes.

Deployable membranes are being increasingly applied in numerous space projects owing to their light weight, small stowage volume and capacity for use at large scales. The geometric design of biomimetic folding is studied to design crease patterns for triangular deployable membranes applied in space. Various crease designs for triangular membranes based on leaf-in, leaf-out and orthogonal patterns are put forward, especially patterns composed of triangular and hexagonal units. In order to analyse the membrane folding method based on biomimetic folding, a set of evaluation indices, including linear dimension ratio, deployment ratio, crease length and junction number, are established. The indices for various membrane folding patterns are calculated according to the crease distributions and geometric relations. Furthermore, a parametric study of crease parameters is performed to determine how the parameters affect folding behaviour and deployment efficiency. These indices can provide an indication to help with the selection of crease patterns and folding parameters for triangular deployable membranes according to the required performance and space mission requirements.

EMD-Based Symbolic Dynamic Analysis for the Recognition of Human and Nonhuman Pyroelectric Infrared Signals.

In this paper, we propose an effective human and nonhuman pyroelectric infrared (PIR) signal recognition method to reduce PIR detector false alarms. First, using the mathematical model of the PIR detector, we analyze the physical characteristics of the human and nonhuman PIR signals; second, based on the analysis results, we propose an empirical mode decomposition (EMD)-based symbolic dynamic analysis method for the recognition of human and nonhuman PIR signals. In the proposed method, first, we extract the detailed features of a PIR signal into five symbol sequences using an EMD-based symbolization method, then, we generate five feature descriptors for each PIR signal through constructing five probabilistic finite state automata with the symbol sequences. Finally, we use a weighted voting classification strategy to classify the PIR signals with their feature descriptors. Comparative experiments show that the proposed method can effectively classify the human and nonhuman PIR signals and reduce PIR detector's false alarms.

[Investigation on prevalence rate of essential tremor in population aged 55 years old and above in Kashkar, between 2008 and 2009].

OBJECTIVE: To investigate the prevalence and clinical feature of essential tremor (ET) in a community cohort of the elderly in Kashkar. METHODS: By using a door-to-door, two-phase screening approach, some 2834 residents of Hans ethnicity were investigated form 2008 to 2009. RESULTS: In this study, 184 ET patients were found. The prevalence rate of ET was 6.49%. The prevalence rate was increased with age and higher in men (8.45%) than in women (4.59%), especially in people aged above 75 years old. The prevalence rate of ET was 7.26% in illiterate people, followed by 7.27%, 5.81%, 5.58% and 9.37% in those having received primary, junior, senior high school and college. The ratio of windowed people in ET patients was 15.21%, higher to the ratio of windowed people in total number. CONCLUSIONS: The prevalence rate of ET increased with age, but not influenced by education.

[Performance improvement of sequencing batch reactor (SBR) treating digested piggery wastewater by addition of raw wastewater].

When digested piggery wastewater was directly treated with a sequencing batch reactor (SBR) process, the efficiency was low with COD removal about 10% and NH4+ -N removal about 70%. The effluent COD concentration was higher than 1000 mg/L and effluent NH4+ -N concentration was 200 mg/L or so. The working state of the reactor was unstable and its performance deteriorated gradually during operation. After adding no-digested piggery wastewater (raw wastewater) to digested piggery wastewater in the influent, the reactor performance was significantly improved with COD removal higher than 80% and NH4+ -N removal up to 99%. The effluent COD concentration was in the range of 250 mg/L to 350 mg/L and effluent NH4+ -N concentration was lower than 10 m/L. The working stability of the reactor was greatly increased. After adding raw wastewater, the ratio of BOD5 to COD in the influent was raised from 0.19 to 0.54, and the ratio of BOD5 to TN was raised from 0.28 to 2.04, which implied an increase of carbon source for microbial growth and denitrification. The elevated denitrification resulting from the increase of carbon source not only promoted the removal of total nitrogen, but also stabilized the pH value by supplementing alkalinity to treatment system.