Search

Thermogravimetric analysis (TGA), coupled with Fourier transform infrared analysis (TG-FTIR) of sewage sludge was carried out to investigate the influence of moisture and oxygen on gas evolution during pyrolysis of sewage sludge. Wet sewage sludge with moisture of 86.47(wt. %) was collected from Shanghai, China. Wet sewage sludge and air dried sewage sludge were used in TG-FTIR analysis, while combustion (air flow) and pyrolysis (nitrogen flow) were separately introduced to achieve comparison. In condition of dry sewage sludge pyrolysis, there were two peaks representing release of separately moisture and volatile. Weight lost 85% in the temperature range of 25-600 °C while the main volatile matters were released before 600 °C. When air flow was introduced, a third peak of char combustion occurred. Wet sewage sludge made no much difference, except for the relatively outstanding peak of moisture release. Temperature regions for each stage were the same for wet and dry sewage sludge from TG curve. However, from the FTIR analysis, ammonia has two peaks between 50 and 450 °C in pyrolysis while ammonia has only one peak between 50 and 300°C.

Oily sludge is inevitably produced in numerous petroleum processing operations. Five oily sludge samples were collected to identify the compositions and to characterize the extracted solids. The results indicated that three fifths of the samples contained significant amounts of oil and could be potentially recovered as energy resources. All of the samples had high concentration of water. The compositions of C, H, and N, as well as H/C in the separated oils were close to those in oil sands bitumen. The high concentration of asphaltenes agreed with the low H/C. The XRD spectra showed that the major minerals contained in the extracted solids were quartz and calcite.

This paper presents an interpolation-based method for multidimensional extrapolation. A series of interpolation formulations are proposed to extrapolate functions normal to the interface between two regions. Theoretical proofs and relevant analysis are also presented. The method developed maintains the characteristics of implicit interface. The interface inside every cell is treated smoothly by assuming that curvature is equal everywhere. The method developed and numerical results are verified by comparing to the results by PDE method and theoretical results. Numerical tests demonstrate that the method developed is first-order accuracy and also more efficient in numerical implementation and more accurate than PDE method.

A RF received signal strength indication (RSSI) circuit with 100MHz to 2.5GHz frequency bandwidth was designed based on Jazz 0.18 μm SiGe HBT process. The RSSI was composed of 4 cascaded limiting amplifier and full wave current rectifier. A novel DC offset compensation circuit was adopted to achieve stable operating point. The circuit was simulated with Cadence design kit. Results showed that the RSSI had a wide dynamic range from 45dBm to 0dBm, operated at a 3.3V single supply. The power consumption is 18.8mW.

The velocity history of free-surface particle for carbon phenolic composites (density is 1.4g/cm3) is obtained based on the loading technology of the light gas gun, the relationship between the striking velocity of flyer and the spall thickness as well as time is investigated. Besides, spall strength and thickness are obtained by analyzing the samples data and curves. The high pressure physical characteristics, such as type Hugoniot curve and Murnagham state equation for this material, are acquired by analyzing the velocity history of free-surface and spall characteristics. This study provides a methodology to quantify spall and physical characteristics for carbon phenolic composites under tensile wave loading.

In this note, we have derived stability for arbitrary switching about absolutely stable subsystem and the stability problem has derived stability for arbitrary switching above all. In the next place we analyze detailed stability for the dwell time switching. In the end, we discuss that the switched system exist stable convex combination switching. At last, we give several numerical results are given to illustrate our derived results.

The Split Hopkinson Pressure Bar (SHPB) is used to investigate the dynamic compressive mechanical behavior of a new foamed ceramic composite under impact loading. The stress versus strain curves are obtained under high strain rates. The test results are considered to be able to assure conformability of the tests, validate the stress equilibrium assumption, and show that the stress versus strain curves of foamed ceramic composite display strain hardening effect and damage softening effect as brittle materials. Meanwhile the curve includes short plateau region while no densification region.

Finite-time stability concerns the boundless of system during a fixed finite-time interval. In this paper, the problem of finite-time stabilization for switched discrete-time systems is addressed. Both the fast switching and slow switching case are considered. In fast switching case, the designed state feedback controller combines controllers for each subsystem and resetting controller at switching instant, it is shown that the resetting controller can reduce the conservativeness on controller design. Under slow switching, state feedback controller is designed with admissible average dwell time. Several numerical examples are given to illustrate the proposed results within this paper.

Removed due to double publication. Original was published http://www.jatit.org/volumes/Vol48No1/27Vol48No1.pdf

The experimental material is source-separated municipal solid waste. Remaining waste from primary assortment is compressed into RDF with mechanical molding equipment. We used high-temperature tube furnace for pyrolysis experiment of RDF. The effects of pyrolysis temperature, material composition, choice of additives and the content of the additive on the productivity of pyrolysis for these samples were investigated; the variation trend of content for K and Na elements in semi-coke was analyzed under various factors. The results show that adding plastics, CaO or DHC-32 is conductive to improve the effect of RDF pyrolysis. Increasing pyrolysis temperature is in favor of the process of pyrolysis reaction, meanwhile, the apparent variation trends are presented for the content of K and Na in semi-coke under the various experimental conditions.

To reflect the relationship between the trapping effect and colorimetric value of prints, this paper establishes an algorithm to calculate the ink trapping ratio. The new algorithm assumed that the second ink of two-color overprint solid forms an evenly distributed and thinner ink layer by keeping the total ink volume as constant and it employed the transmittance of single solid ink and overprint solid to compute the ratio of the thickness of the second ink layer printed on the first ink layer and on the blank paper on basis of Lambert's law. Because of the difficulties of measuring the transmittance of prints, it used the Clapper-Yule model to calculate them. To evaluate it, the ink trapping ratio computed by the densitometry method and the new algorithm for two sets of two-color overprint solid were adopted to predict the spectral reflectance of them. By comparing the CIELAB color difference between the calculated and measured value of spectral reflectance, the proposed new algorithm is precisely defined and it improves the calculation accuracy of ink trapping.

Ferromagnetic base composite material is widely used in aerospace field, and its high pressure mechanical properties become the study hot spot in recently years. Aimed at an advanced ferromagnetic base composite material, its impact compression behaviors were investigated by means of Light Gas Gun (LGG). The shock wave velocity (D) and the particle velocity (u) behind the shock wave were measured and calculated by using Asymmetry Impact and Direct Measurement. Based on the experimental results and calculated results, a D-u type Hugoniot curve was obtained. The Grüneisen equation of state for the ferromagnetic base composite material and its coefficients were obtained on the basis of its Hugoniot curve.

Optical dot gain is the key point of halftone reconstruction study, and has always been a meaningful topic of theoretical study. The Yule–Nielsen formula is by far the most widely used research method of optical dot gain. However, solving the Yule–Nielsen parameter n remains a difficult problem. This paper disregards solving for the Yule–Nielsen parameter n, analyzes the light scattering and osmotic effect of halftone presswork, deduces the exact expressions of blank area of presswork, and determines the reflectivity of the dot part and halftone presswork according to the point spread function and probability method. Furthermore, this paper analyzes how the optical dot gain depends on the dot area coverage of presswork, ink layer transmittivity, and paper-based spectral reflectivity. In addition, a new algorithm model for optical dot gain is established. By employing the Clapper–Yule Model to calculate the spectral transmittance of printing ink and comparing it with the practical measured spectral reflectivity of the halftone presswork proof, the accuracy of the model established in this paper is fully verified.

The MTS810 and SHPB are used to experimentally study the quasi-static and dynamic mechanical properties of three-dimensional E-glass fiber-reinforced composite. Stress-strain curves along the plane and thickness direction are obtained under varying strain rates, ranging from 10-3 to 103s-1. Experimental results show that strain rate has a significant effect on the material response. It is found that the compressive strength and the modulus increase with increasing strain rate, the failure strain, however, decreases slightly. But, the effect of strain rate in-plane and through thickness directions is different. A higher strain rate sensitive modulus and failure is found in the thickness direction, while a higher strain rate sensitive failure strength is found in the in-plane direction.

In this paper, the classical sewage sludge and coal co-combustion power generating system was optimized. The regenerative steam in the extraction turbine was partly used for the sludge drying. And then, the mathematics model was established based on the exergy theory. Several extraction points were compared to find out the most optimization parameters (drying efficiency of the dryer, pressure and tempreture). The result showed that, with different steam temperature and pressure at different extraction points, the influence to the system exergy efficiency caused by the percentage of moisture and drying efficiency was different. When the sludge moisture content went to about 35%, the generating capacity increment was moderating. After the calculation and comparison, the error between the calculation results of the mathematical optimization model and the classical thermodynamic method was very small. The calculation in mathematical optimization model based on exergy analysis was relatively simple, and analysis of the relationship between variables was easier.

A damage evolution law for porous phenolic composites is developed by using phenomenological point, which along with the improved Johnson-Cook model is then implemented into a finite difference code for one-dimensional strain wave problem. The velocity history of free-face particle is recorded and correlated with the simulated result to evaluate the damage parameters. Good agreement shows that the proposed damage evolution law and spall rule are feasible. Besides, the relationships between the striking velocity of flyer and the spall thickness as well as spall time are investigated. This study provides a methodology to quantify the damage evolution of phenolic composites under impact loading.