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Maximizing biomass utilization: An integrated strategy for coproducing multiple chemicals

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Journal of Energy Chemistry 2025年第1期100卷 180-191页

作者： Byeongchan Ahn Sua Jo Jonggeol Na J.Jay Liu Young-Ju Kim Wangyun Won department of Chemical and Biological engineering Korea University department of Chemical engineering (Integrated process) Kyung Hee University department of Chemical engineering and Materials Science Ewha Womans University department of Chemical engineering Pukyong National University Resources engineering Plant Research department Korea Institute of Geoscience and Mineral Resources

Lignocellulosic biomass is one of the viable solutions to alleviate the global warming. However, the limited utilization of biomass majorly focused on cellulose and hemicellulose restricts the economic and environmental feasibilities. To cope with this issue, we proposed an integrated process of co-producing 1,6-hexanediol（1,6-HDO） with tetrahydrofuran and adipic acid from biomass, referred to as Strategy A. To compare the impacts of lignin upgrading and feedstock, Strategy B, which co-produces tetrahydrofuran alone, and Strategy C, which is the traditional route to produce 1,6-HDO from fossil fuels, were used. Heat networks are also designed to reduce operating costs and indirect carbon emissions due to energy consumption, saving 87% and 83% of the heat and cooling requirements, respectively, in Strategy A. The market competitiveness of Strategy A was evaluated by determining the minimum selling price through techno-economic analysis, and sustainability was thoroughly investigated by quantifying the environmental impacts through both midpoint and endpoint life-cycle assessments（LCAs）.Strategy A was found to be the most favorable both economically（USRDSCHARDOLLAR3,402/ton） and environmentally（-26.9 kg CO2eq.）. This indicates that lignin valorization is not only economically but also environmentally preferred. Finally, changes in economic and environmental feasibilities depending on economic, process, and environmental parameters were investigated using sensitivity and uncertainty analyses. The results of these analyses provide valuable insight into bio-based chemical production.

关键词： Biorefinery Carbon mitigation Climate change Global warming Lignin utilization Bioeconomy

Microstructure and corrosion behavior of NiTi shape memory alloys sintered in the SPS process

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International Journal of Minerals,Metallurgy and Materials 2019年第10期26卷 1311-1321页

作者： C.Velmurugan V.Senthilkumar P.S.Kamala department of production engineering National Institute of Technology

NiTi shape memory alloys(SMAs) was developed using the spark-plasma sintering(SPS) process with different average particle size(45 μm and 10 μm) under various temperature. The influence of particle size and temperature on the density, microstructure, and corrosion behavior of the NiTi in simulated body fluid was examined. The porosity decreased with increasing sintering temperature and decreasing particle size, which resulted in an increase in density of the alloy. Increasing the sintering temperature led to the formation of Ni-and Ti-rich intermetallic such as Ni3Ti and NiTi2. The formation of these secondary phases influenced the corrosion behavior of NiTi by changing its chemical composition. The planar structure of NiTi was transformed into a dendritic structure at 900℃, which resulted in the formation of uniform oxide and phosphate layers on the entire surface. A high corrosion potential and low corrosion current density were achieved with NiTi prepared with 10 μm particles at 900℃, which exhibited superior corrosion resistance.

关键词： shape memory alloys NiTi microstructure corrosion spark-plasma sintering

EXPERIMENTAL AND NUMERICAL ANALYSIS OF LAMINAR AND LOW TURBULENT FLOW DISTRIBUTIONS IN INLET DIVIDING HEADER OF SHELL AND TUBE HEAT EXCHANGER

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Journal of Hydrodynamics 2010年第4期22卷 494-502页

作者： KANNAN K. RUDRAMOORTHY R. department of production engineering PSG College of Technology

Flow distribution headers play a major role in heat *** selection of header diameter,branch pipe diameter,branch pipe spacing *** based on the designer＇s experience and general guide *** proper selection of the header dimensions will yield uniform flow distribution in heat exchangers,which in turn will enhance the heat exchanger *** this work,the flow distribution in branch pipes and the pressure variation across the branch pipes in laminar and low turbulence region is studied with two models of the inlet dividing *** the numerical analysis has been applied,its inability to predict the no flow condition through the branch pipes is *** results are presented in the form of flow rate ratio through branch pipes and nondimensional coefficients across branch pipes which are useful to apply the existing mathematical models for the present experimental setup.

关键词： shell and tube heat exchanger inlet dividing header uniform flow distribution experimental setups numerical analysis

Synthesis and forming behavior of aluminium-based hybrid powder metallurgic composites

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International Journal of Minerals,Metallurgy and Materials 2014年第2期21卷 181-189页

作者： M.Ravichandran A.Naveen Sait V.Anandakrishnan department of Mechanical engineering Chendhuran College of Engineering and Technology department of production engineering National Institute of Technology

Aluminium-based metal matrix composites were synthesized from Al-TiO2-Gr powder mixtures using the powder metallurgy technique and their forming characteristics were studied during cold upsetting. Green cylindrical compacts of pure Al, Al-5wt%TiO2, Al-5wt%TiO2-2wt%Gr, and Al-5wt%TiO2-4wt%Gr were made using a 400-kN hydraulic press equipped with suitable punch and die and by sintering at （590 ± 10）°C for 3 h. Cold upset forging tests were carried out, the true axial stress （σz）, the true hoop stress （σ？）, and the true hy-drostatic stress （σm） were evaluated and, their behavior against the true axial strain （εz） was also analyzed. It is observed that the addition of 5wt%TiO2 into the Al matrix increasesσz,σ？, andσm. The addition of both TiO2 and Gr reinforcements reduces the densification and defor-mation characteristics of the sintered preforms during cold upsetting. Microstructure analyses of the as-sintered and cold upset forged speci-mens also were carried out to substantiate the experimental results.

关键词： metal matrix composites cold upsetting powder metallurgy workability

Al–TiO_2–Gr powder metallurgy hybrid composites with cold upset forging

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Rare Metals 2014年第6期33卷 686-696页

The cold upsetting studies were carried out for the aluminium metal matrix hybrid composites in the present study. Aluminium metal matrix hybrid composites were synthesised through powder metallurgy route from ball-milled powders to yield the following compositions：Al ＋ 2.5 wt% TiO2＋ 2 wt% Gr, Al ＋ 2.5 wt% TiO2＋ 4 wt% Gr, Al ＋ 5.0 wt% TiO2＋ 2 wt% Gr and Al ＋ 5.0 wt% TiO2＋ 4 wt% Gr. The compaction process was carried out using suitable punch and die in 40 k N hydraulic press, and sintering was done in an electric muffle furnace at the temperature of 590 °C for 3 h. The sintered preforms were subjected to incremental compressive loading of 10 k N until the cracks were found at the free surface. The true axial stress, true hoop stress, true hydrostatic stress and true effective stress were calculated for all the preforms, and all these stresses are correlated with the true axial strain. The stress ratio parameters（rz/reff, rh/reff, rz/rmand rh/rm） of the all preforms were correlated with true axial strain. The maximum true axial stress, true hoop stress, true effective stress and hydrostatic static stress are obtained for the composite containing5 wt% of TiO2 and 4 wt% of graphite and the minimum ones are obtained for composite containing 2.5 wt% of TiO2 and 2 wt% of graphite.

关键词： Metal matrix composites Cold upsetting Powder metallurgy

Buried interface bridging for inverted cesium-formamidinium triiodide perovskite solar cells with long operational stability

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Science China Chemistry 2025年第01期 163-173页

作者： Chenhui Zhang Chunjun Liang Fulin Sun Ting Zhu Xinghai Huang Yuzhu Guo Xinyu Guo Kunyang Ge Dan Li Fangtian You Zhiqun He Key Laboratory of Luminescence and Optical Information Ministry of Education Institute of Optoelectronic TechnologyBeijing Jiaotong University department of Physics School of Physical Science and Engineering Beijing Jiaotong University

In the field of perovskite solar cells(PSCs), the research on defects in the buried interface has been relatively limited due to its non-exposure; however, this interface significantly impacts the performance enhancement of inverted PSCs. This study employs phenylethylammonium chloride(PEACl) molecules as a buffer layer to modify the buried interface of p-i-n structured PSCs,aiming to enhance the uniformity of self-assembled monolayers(SAMs) and facilitate the uniform nucleation and growth of perovskite films on the substrate. Furthermore, the introduction of the PEACl buffer layer effectively passivates defects at the bottom of the perovskite layer and notably enhances the crystal quality of the perovskite film by mitigating residual stress,thereby reducing nonradiative recombination loss. Following these optimizations, the MA-free PSCs treated with PEACl achieve a power conversion efficiency(PCE) of 24.11%, with significant improvements in storage, thermal stability, and operational stability. Particularly noteworthy is the device's performance in an unencapsulated state, whereas after 1,500 hours of continuous light operation stability testing, it retains 97% of its original efficiency. This study not only enriches the systematic understanding of the characteristics of the buried interface in PSCs but also contributes significantly to advancing the commercial production of perovskite photovoltaic technology.

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Experimental Investigation on Friction Welding of UNS S32205 Duplex Stainless Steel

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Acta Metallurgica Sinica(English Letters) 2014年第6期27卷 995-1007页

作者： P. M. Ajith P. Sathiya S. Aravindan department of production engineering National Institute of Technology department of Mechanical engineering Indian Institute of Technology Delhi

UNS S 32205 duplex stainless steel specimens were joined by continuous drive friction welding process. The experiments were conducted as per the Taguchi（L16 orthogonal array） method. The friction welding process parameters such as heating pressure, heating time, upsetting pressure, upsetting time, and speed of rotation were fixed with low,medium, and high levels of range based on the machine capacity, and the required knowledge was acquired from the preliminary experiments. The joint characterization studies included micro structural examination and evaluation of mechanical properties of the joints. Microhardness variation, impact toughness, and tensile strength of the joints were evaluated. Neither a crack nor an incomplete bonding zone was observed. The tensile strength of the joints was higher than the strength of the base material, and the friction and upsetting pressures were found to influence the joint strength. The tensile strength of all the welds was observed to be increasing with an increase in the rotational speed. The toughness of the friction welds was evaluated at room temperature and also at subzero（cryo） temperature conditions. The toughness for friction welds was found to be superior to the fusion welds of duplex stainless steel at room temperature and cryo conditions. Weldments exhibited better corrosion resistance than the parent material.

关键词： Duplex stainless steel Hardness Tensile strength Toughness Microstructure Corrosion

Wide bandwidth acoustic transmission via coiled-up metamaterial with impedance matching layers

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Science China(Physics,Mechanics & Astronomy) 2019年第6期62卷 37-44页

作者： Xiao Jia Yang Li Yinghao Zhou Minghui Hong Ming Yan department of Materials Science and engineering and Shenzhen Key Engineering Lab for Powder Production for 3D Printing of Aircraft Engines Southern University of Science and Technology department of Electrical and Computer engineering National University of Singapore

Many acoustic metamaterials suffer from a narrow bandwidth transmission because of the impedance mismatch at the airmetamaterial interface. In this paper, a two-dimensional impedance-matched metamaterial with broadband transmission performance is investigated. The impedance matching layer is introduced for a gradient variation of effective impedance from the inlet of the unit to the outlet. The effective medium theory and corresponding effective model are used to explain the underlying mechanism. The improved energy transmission of our designs is demonstrated by experiment and numerical simulation within a broad frequency bandwidth over 6 kHz. Our impedance-matched design can be used to enhance sound absorption, which is expected to present improved acoustic performance in the applications of acoustic damper and muffler.

关键词： general linear acoustics structural acoustics and vibration acoustical measurements and instrumentation wavestructure interactions

Case Depth Measurement of Induction Hardening Using Image Processing

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材料热处理学报 2004年第5期25卷 564-566页

作者： Kitti Pongsathaporn Pramuk Jenkittiyon Siriporn Daopiset Somnuk Watanasriyakul production engineering department Engineering Faculty King Mongkut's Institute of Technology North Bangkok ThailandProduction Engineering Department Engineering Faculty King Mongkut's Institute of Technology North Bangkok ThailandProduction Engineering Department Engineering Faculty King Mongkut's Institute of Technology North Bangkok ThailandProduction Engineering Department Engineering Faculty King Mongkut's Institute of Technology North Bangkok Thailand

Case depth measurement of the induction hardened steel parts is necessary for quality control. Vickers microhardness test is the most industrially accepted method to identify the case depth. But this method is a time consuming one and it requires expensive equipment. The aim of this study is to develop a different method to determine the case depth using image processing. The surface hardened steel samples were cross cut, ground and etched with Nital. The etched macrosectioned specimens were scanned by a scanner. The scanned images were evaluated by the developed software. The principle of the software is to identify the gray level difference. The effective case depths of the surface hardened specimens obtained by Vickers microhardness test and the developed method were compared. It was found that the deviation of the developed method was ±0.12 mm at the case depth range of 0.6 - 2.0 mm and mm at the case depth range of 2.1 - 4.3 mm. The measuring time was only 20% of Vickers microhardness test. The deviation range is much lower than the tolerance case depth specification for induction hardening in general.

关键词：图像处理表面硬化深度感应淬火质量控制