Paper mill sludge as a renewable substrate for the production of acetone-butanol-ethanol using Clostridium sporogenes NCIM 2337

In the present study, pre-treated paper mill sludge (PMS) was evaluated extensively as a substrate for production of acetone-butanol-ethanol using Clostridium sporogenes NCIM 2337. The PMS was subjected to three types of pre-treatment methods namely alkali, mechanical, and thermal treatment and was analyzed by SEM. The pre-treatment of PMS by alkali was observed to be more effective over the other pre-treatment methods. The alkali pre-treated sludge was then made to undergo fermentation, which showed the conventional process of acidogenesis followed by solventogenesis. The acetone, butanol, and ethanol concentration for 15% alkali pre-treated PMS was estimated to be maximum.     

配加预处理脱硫灰对铁矿烧结基础特性的影响

 半干法脱硫灰堆弃处理占用土地且容易造成二次污染,将脱硫灰预处理后替代CaO熔剂配入烧结有望充分利用其中的熔剂组分,实现脱硫灰在钢铁企业的闭路资源化利用。研究了脱硫灰配加焦粉加热分解特性及替代CaO熔剂配加对铁矿粉烧结基础特性的影响。结果表明,配加1%焦粉可以有效提高脱硫灰分解率,减少CaSO₄的生成。随着预处理脱硫灰替代CaO比例的增加,铁矿粉同化温度和黏结相强度呈现先增加后减小的趋势;液相流动性呈现单调增加趋势,当替代比超过40%时,液相流动性形成了流动性很大的“假象”;黏结相微观结构表明,替代比例小于40%时,有利于烧结试样中铁酸钙的生成;综合考虑,最佳的替代比例应小于40%。     

通过晶种胶作导向剂的凝胶预陈化路线合成多级孔道FAU/α-Al2O3整体材料

以整体型α-Al2O3为载体，晶种胶作导向剂，通过凝胶预陈化路线合成了多级孔道FAU整体材料。对合成的样品进行了FT-IR、XRD、SEM和N2吸附脱附表征。根据实验结果确定了晶种胶、凝胶预处理及预陈化步骤的作用，同时提出了不同路线生成氧化铝复合物可能的合成机理。结果发现：负载的FAU沸石的粒径、形状及数量可通过改变晶化凝胶的组成，并且α-Al2O3载体的结构没有明显改变。具有简单、可重现且易将三重孔道结构融于成型的整体材料中的特点，通过晶种胶预处理的凝胶预陈化路线可加强载体内表面与沸石间的界面作用，形成纯相FAU晶体沉积在α-Al2O3载体骨架表面的形貌。另外，该方法可为其他的多级孔道沸石的合成提供思路。                                  

Drivers of microbial community composition in mesophilic and thermophilic temperature-phased anaerobic digestion pre-treatment reactors

Temperature-phased anaerobic digestion (TPAD) is an emerging technology that facilitates improved performance and pathogen destruction in anaerobic sewage sludge digestion by optimising conditions for 1) hydrolytic and acidogenic organisms in a first-stage/pre-treatment reactor and then 2) methogenic populations in a second stage reactor. Pre-treatment reactors are typically operated at 55–65 °C and as such select for thermophilic bacterial communities. However, details of key microbial populations in hydrolytic communities and links to functionality are very limited. In this study, experimental thermophilic pre-treatment (TP) and control mesophilic pre-treatment (MP) reactors were operated as first-stages of TPAD systems treating activated sludge for 340 days. The TP system was operated sequentially at 50, 60 and 65 °C, while the MP rector was held at 35 °C for the entire period. The composition of microbial communities associated with the MP and TP pre-treatment reactors was characterised weekly using terminal-restriction fragment length polymorphism (T-RFLP) supported by clone library sequencing of 16S rRNA gene amplicons. The outcomes of this approach were confirmed using 454 pyrosequencing of gene amplicons and fluorescence in-situ hybridisation (FISH). TP associated bacterial communities were dominated by populations affiliated to the Firmicutes, Thermotogae, Proteobacteria and Chloroflexi. In particular there was a progression from Thermotogae to Lutispora and Coprothermobacter and diversity decreased as temperature and hydrolysis performance increased. While change in the composition of TP associated bacterial communities was attributable to temperature, that of MP associated bacterial communities was related to the composition of the incoming feed. This study determined processes driving the dynamics of key microbial populations that are correlated with an enhanced hydrolytic functionality of the TPAD system.     

Study on effects of pre-treatment and surface roughness on tensile-shear strength of 2060 Al–Li alloy adhesive joints

The forces between adhesive and adherend mainly influenced by the pre-treatment technology of the substrates have important effects on the bonding strength. In this paper, the influence of different pre-treatment processes and surface roughness on the tensile-shear strength of 2060 Al–Li alloy adhesive joints as well as related mechanism was investigated. In this perspective, substrates were processed by mechanical abrasion at different levels and by phosphoric acid anodizing, which resulted in different surface topographies that were characterized by means of roughness measurements. Single-lap joints were prepared using a two-component epoxy adhesive. The tensile-shear strength of joints was measured via destructive testing and the failure modes were analyzed to evaluate the quality of bonding. Results showed that with the increase of surface roughness of Al–Li alloy, the tensile-shear strength of the adhesive joints increased and the failure modes changed from interfacial failure to cohesive failure. The groove structures formed during mechanical abrading were regarded as being responsible for this strengthening behavior. Moreover, a rough porous membrane was produced on adherents’ surface by phosphoric acid anodizing, causing a consolidation of adhesion at the adhesive-substrate interface.     

Friction Spot Joining of aluminum AA2024/carbon-fiber reinforced poly(phenylene sulfide) composite single lap joints: Microstructure and mechanical performance

Friction Spot Joining is a promising alternative joining technology for polymer–metal hybrid structures. In this work, the feasibility of Friction Spot Joining of aluminum AA2024-T3 (bare and alclad)/carbon-fiber reinforced poly(phenylene sulfide) is reported. The process temperature and the microstructure of the joints were investigated. Lap shear tensile strength as high as 27 MPa was achieved by using aluminum bare specimens. Sand blasting was also performed as an effective mechanical surface pre-treatment on aluminum surfaces, which resulted in higher surface roughness and accordingly improved mechanical performance for the selected conditions. In addition, the alclad specimens exhibited promising mechanical performance (lap shear strength of up to 43 MPa) that justifies further investigations. Finally, the bonding and failure mechanisms of the joints are briefly discussed.     

气田含油含醇污水预处理运行参数优化

在气田开采中,为了抑制天然气水合物的生成,通常向气井和采气管线注入甲醇并在集气站内分离,产生了含油含醇污水。由于甲醇属毒性物质,含醇污水直接排放会影响环境,因而需要进行无公害化处置。文章介绍了榆林气田南区含油含醇污水预处理处理流程及实际生产存在问题,并通过研究含油含醇污水的组成性质,对预处理药剂的加注量进行优化,使得处理后污水的各项指标达到最佳,减少甲醇回收装置的堵塞及腐蚀,确保生产单元平稳运行。     

Modelling the supercritical fluid extraction of edible oils and analysis of the effect of enzymatic pre-treatments of seed upon model parameters

In this work the supercritical fluid extraction of grape seed oil in a semi-continuous unit has been modelled and discussed in detail. The model embodies the concept of broken plus intact cells, and assumes series mass transfer from intact to broken cells, and then to the fluid phase. The numerical solution has been accomplished by the method of lines using finite differences with upwind flow correction. Experimental extraction curves for both untreated seed and enzymatically pre-treated seed have been modelled in order to evaluate the performance of the model in terms of correlation capability and physical meaning of the parameters. The extraction curves for untreated and treated seed have been accurately represented with average deviations between 2.30 and 7.25%. The model parameters that are intimately related with the internal structure of the seed are the grinding efficiency (or fraction of broken cells) and the internal mass transfer coefficient. Both parameters have been optimised and attained physically sound values, in view of the fact they increased after the enzymatic pre-treatment, and obeyed simple restrictions imposed. The model has been able to generate coherent concentration profiles in the bed and elution curves as well.     

A comparison of reactive plasma pre-treatments on PET substrates by Cu and Ti pulsed-DC and HIPIMS discharges

PET web samples have been treated by magnetically enhanced glow discharges powered using either medium frequency pulse direct current (p-DC) or low frequency high power pulse (HIPIMS) sources. The plasma pre-treatment processes were carried out in an Ar–O₂ atmosphere using either Cu or Ti sputter targets. XPS, AFM and sessile drop water contact angle measurements have been employed to examine changes in surface chemistry and morphology for different pre-treatment process parameters. Deposition of metal oxide onto the PET surface is observed as a result of the sputter magnetron-based glow discharge web treatment. Using the Cu target, both the p-DC and HIPIMS processes result in the formation of a thin CuO layer (with a thickness between 1 and 11 nm) being deposited onto the PET surface. Employing the Ti target, both p-DC and HIPIMS processes give rise to a much lower concentration of Ti (< 5 at.%), in the form of TiO₂ on the PET treated surface. The TiO₂ is probably distributed as an island-like distribution covering the PET surface. Presence of Cu and Ti oxide constituents on the treated PET is beneficial in aiding the adhesion but alone (i.e. without oxygen plasma activation) is not enough to provide very high levels of hydrophilicity as is clear from sessile drop water contact angle measurements on aged samples. Exposure to the plasma treatments leads to a small amount of roughening of the substrate surface, but the average surface roughness in all cases is below 2.5 nm. The PET structure at the interface with a coating is mostly or wholly preserved. The oxygen plasma treatment, metal oxide deposition and surface roughening resulting from the HIPIMS and p-DC treatments will promote adhesion to any subsequent thin film that is deposited immediately following the plasma treatment.