Catalytic degradation of waste high-density polyethylene into fuel products using BaCO3 as a catalyst

Waste high-density polyethylene (HDPE) was degraded thermally and catalytically using BaCO₃ as a catalyst under different conditions of temperature, cat/pol ratio and time. The oil collected at optimum conditions (450 °C, 0.1 cat/pol ratio and 2 h reaction time) was fractionated at different temperatures and fuel property of the fractions and parent oil was evaluated by their physicochemical parameters for fuel tests. The results were compared with the standard values for gasoline, kerosene and diesel oil. Boiling point distribution (BPD) curves were plotted from the gas chromatographic study of the samples and compared with that of the standard gasoline, kerosene and diesel. The oil samples were analyzed using GC/MS in order to find out their composition. The physical parameters and the composition of the parent oil and its fractions support the resemblance of the samples with the standard fuel oils. The light fractions best match with gasoline, the middle fractions match with kerosene and the heavier fractions match with diesel oil in almost all of the characteristic properties.     

有机碱催化Knoevenagal法合成肉桂酸及其工艺优化

本文以苯甲醛和丙二酸为原料,吡啶等有机碱为催化剂,利用Knoevenagal反应合成肉桂酸,从而降低了反应温度,提高了产率和产品纯度,简化了合成工艺。同时,比较和分析了不同弱碱催化剂对肉桂酸合成产率的影响,结果表明吡啶的催化效果最好,并通过正交试验探讨了有机碱催化作用下,不同工艺参数对肉桂酸产率的影响,确定反应的最佳工艺条件为:以吡啶为催化剂,反应物苯甲醛/丙二酸摩尔比取1:3,催化剂用量0.02mol,反应时间为90min,肉桂酸产率可达90%。     

Ceramic bodies obtained using the waste products of the fluorite concentration plants

Translated from Steklo i Keramika, No. 9, pp. 21–22, September, 1991.     

A robust technique for process flowsheet optimization using simplified model approximations

Recently, embedded simplified process models have been shown to be very efficient for process simulation. When compared to the direct use of rigorous models, this approach has the potential to reduce the computational effort of process simulation by up to an order of magnitude or more. Application of this approach to process optimization should therefore lead to similar savings in computational effort as well as substantial improvement of the process.

However, current simplified model embedding schemes applied to process optimization cannot, in general, converge to the optimum defined by the more rigorous process models. Consequently, they require an expensive rigorous model optimization starting from the solution of the simplified model optimum to guarantee convergence.

In this paper we develop a framework that incorporates simplified models into an optimization algorithm and guarantees convergence to the rigorous model optimum. Here rigorous process models are evaluated only when necessary to insure progress toward the optimal solution. A theoretical justification of the algorithm is presented and several process examples are solved to demonstrate the effectiveness of this approach.     

Aligning carbon nanotubes,synthesized using the arc discharge technique,during and after synthesis

Alignment of multi-walled carbon nanotubes (MWCNTs) is demonstrated using physical forces both during synthesis, as well as post-synthesis through the arc discharge technique. The arc discharge process results in relatively straight and defect free MWCNTs compared to other techniques such as chemical vapor deposition. A scraper enables alignment of these straight MWCNTs during synthesis. Additional tailoring of the direction of alignment is seen to be possible even at room temperature, using physical forces in the form of scratch marks on the soot. Using a hand operated roller, on the surface of the soot, also results in the alignment of MWCNTs along the rolling direction. Alignment of MWCNTs is confirmed using scanning electron microscopy and it results in distinct changes in X-ray diffraction and energy dispersive spectroscopy data. These results are significant from the perspective of obtaining aligned MWCNTs, in large quantities, in a relatively inexpensive manner.     

Quasi two-dimensional carbon nanobelts synthesized using a template method

Carbon nanobelts have been synthesized using nanoporous anodic alumina as template and ethanol as precursor. The length and width are tens of micrometers and 470 nm, respectively. The thickness was measured to be 5 nm, exhibiting a high-aspect-ratio morphology. After annealing, the crystallinity of the nanobelts can be improved. The formation mechanism of such morphology is demonstrated as a radial deformation of large thin nanotubes. This is disclosed for the first time in the literature regarding the attainment of a quasi two-dimensional nanocarbon via a template route. Field emission measurements on the sample annealed at 800 °C show a turn-on voltage 3.25 V/μm and stable long-term emission efficiency. The lower threshold voltage is attributed to the strong edge emitter effect.     

碳酸钾法制备茶渣活性炭工艺优化及吸附性能

以牡丹花茶饮料生产末端残渣(以下简称茶渣)为原料,以2 mol/L碳酸钾溶液为活化剂,制备茶渣活性炭。研究了剂料比、活化温度、活化时间对茶渣活性炭吸附性能的影响。结果表明,碳酸钾法制备残渣活性炭的最佳工艺参数为:碳酸钾/茶渣剂料比1∶1.5(质量比)、活化温度500℃、活化时间1 h,所得活性炭水分、灰分、得率、碘吸附值分别为4.67%,3.10%,9.89%,931.93 mg/g。接近于国家一级活性炭对碘吸附值的要求标准1 000 mg/g。pH=5时,茶渣活性炭对于苯酚最大吸附量和吸附率分别达到9.35 mg/g,吸附率94%。     

磷酸法茶渣活性炭的制备及吸附性能

以牡丹花茶饮料生产末端茶渣(以下简称茶渣)作为活性炭制备原料,考察磷酸与茶渣的浸渍比、活化温度、活化时间对活性炭得率、碘吸附值的影响。结果表明,磷酸法制备茶渣活性炭的最佳工艺参数为:浸渍比(磷酸/原料)为1∶2.5,活化温度550℃,活化时间0.5 h。活性炭得率为29.91%,碘吸附值为968.75 mg/g。含水率为4.80%,灰分含量为17.25%。接近于国家一级活性炭对碘吸附值的要求标准1 000 mg/g。100 mL浓度为10 mg/L的苯酚废水,加入0.1 g活性炭,25℃振荡1 h,pH=5时,茶渣活性炭对于苯酚吸附量达到8.67 mg/g,吸附率约为87%。     

磷酸法茶渣活性炭的制备及吸附性能

以牡丹花茶饮料生产末端茶渣(以下简称"茶渣")作为活性炭制备原料,考察磷酸与茶渣的浸渍比、活化温度、活化时间对活性炭得率、碘吸附值的影响。结果表明,磷酸法制备茶渣活性炭的最佳工艺参数为:浸渍比(磷酸/原料)为1∶2.5,活化温度550℃,活化时间0.5 h。活性炭得率为29.91%,碘吸附值为968.75 mg/g。含水率为4.80%,灰分含量为17.25%。接近于国家一级活性炭对碘吸附值的要求标准1 000 mg/g。100 mL浓度为10 mg/L的苯酚废水,加入0.1 g活性炭,25℃振荡1 h,pH=5时,茶渣活性炭对于苯酚吸附量达到8.67 mg/g,吸附率约为87%。     

Performance optimization of acrylonitrile butadiene styrene/thermoplastic polyurethane composite foams blown with carbon dioxide using Taguchi technique

In this study, acrylonitrile butadiene styrene (ABS)/thermoplastic polyurethane (TPU) composite foam blown with CO₂ was fabricated. Optimization was done by design of experiment (DOE) on the cellular structure using the Taguchi method. Foaming time (20, 40, and 80 s), saturation pressure (4, 5.5, and 7 MPa), and foaming temperature (80, 90, and 120°C) are the input parameters. The results obtained from the signal-to-noise (S/N) analysis showed that the most effective factor on the cell density (CD) was the saturation pressure and its influence rate was 48.05%, and also, the CD improved with the increase in the saturation pressure because the high saturation pressure leads to an enhancement in gas solubility and the rate of cell nucleation. Moreover, the foaming temperature and the foaming time had a noteworthy impact on the void fraction and the cell size (CS), and they should be controlled accurately. The impression rate of the foaming time on the CS was 50.86%, and also, with increase in the temperature and the time of foaming, the void fraction showed an increasing trend. The optimal values for the CD, the CS, and the void fraction were predicted to be 1.18 × 10⁹ cells/cm³, 5.37 μm, and 0.5744%, respectively.     

Ionic liquid-stabilized non-spherical gold nanofluids synthesized using a one-step method

Ionic liquid (IL)-stabilized non-spherical gold nanofluids have been synthesized by a one-step method in aqueous solution. The whole reaction proceeded in room temperature. In the presence of amino-functionalized ionic liquids, gold nanofluids with long-wave surface plasmon resonance (SPR) absorption (>600 nm) could be obtained by adopting tannic acid as the reductant. The specific SPR absorption was related to the non-spherical gold nanoparticles including gold triangle, decahedra, and icosahedra nanocrystals. All the nanocrystals were observed by transmission electron microscopy. It was deduced that the formation of non-spherical gold nanofluids was related to the hydroxyls in tannic acid while IL acted as the synthesis template.     

Malachite green dye purification from effluent using synthesized ceramic clay: Characterisation; optimization and scale up

The rise of industry is crucial to any nation's progress. Pollution levels increased as industrialization expanded, enhancing the necessity to adopt environmental practices. The purpose of this research is to treat the Malachite Green Dye (dye-containing) wastewater with locally available ceramic clay. The ceramic clay was characterized by x-ray diffraction, scanning electron microscopy, thermal analysis, and Fourier transform of infrared and found to be suitable for bioadsorption. Various operating parameters, such as effluent alkalinity and initial dye concentrations; adsorbent size; mass loading; working temperature; experimental time, agitation, and ionic strength, were optimized to treat the effluent up to the recycling limit. The results show that the best conditions for achieving 99.6% dye concentration were an initial pH of 4, a particle size of 2.5 mm, agitations of 210 rpm, a temperature of 35 °C, dosing of 6 g/L, a dye concentration of 50 mg/L, a time of 300 min, and an ionic strength of 0.5 mM. The order of kinetics, isotherms, and thermodynamic studies supported the research findings. In the majority of cases, ceramic clay may be used as a dye remover, which is an exciting benefit for the environment.     

Formulation of a standard deviate observer by a nonlinear optimization technique

A standard deviate observer (SDO) has been formulated that can predict the average color mismatches of metameric color pairs by 20 Stiles' observers. A nonlinear optimization technique, rather than a statistical analysis, has been employed to derive it. The colorimetric characteristics of the present SDO are compared with those of SDOs previously proposed.     

Analysis and optimization of municipal solid waste combustion in a reciprocating incinerator

A mathematical model is presented for the combustion of municipal solid waste in a reciprocating incinerator. The most preferable incinerator is determined by detailed simulation and analysis of different incinerator shapes. Furthermore, the optimal design and operating parameters are obtained by analyzing the injection angle and velocity of the secondary air. Both the results of numerical simulation and practical operation show favorable combustion state, low contaminants emission, and suitability for the combustion characteristics of Chinese municipal waste and the treating requirements. This study provides an important reference for the optimizing design and operation of municipal solid waste incinerator.