A waste heat recovery system development and analysis using ORC for the energy efficiency improvement in aluminium electrolysis cells

The present work investigates an active waste heat recovery system for the side walls of the aluminium electrolysis cells, enabling utilization of the extracted heat in power generation. This will potentially lead to energy efficiency improvement in the primary aluminium production industry and an enhanced aluminium production rate. An experimentally validated loop thermosyphon heat pipe model was used for heat extraction from the cell side wall. Boosting system thermal efficiency through waste heat recovery, by means of a heat utilization system, and increasing the level of control, as well as thermal equilibrium, stand as the main addressed objectives of the current study, which consequently result in an increased aluminium production rate. An organic Rankine cycle is incorporated into the system, and its performance is evaluated, taking into consideration the operating situations in terms of available temperature and thermal power range.     

铝金属化纸制备工艺的专利技术发展

通过对铝金属化纸领域专利技术的收集、分析、标引,介绍了铝金属化纸的制备方法及种类,包括铝粉涂布、铝箔纸以及可降解回收的真空镀铝纸等;并对其专利申请量、区域分布以及渡铝技术进行了分析,同时对各技术的发展历程和改进情况进行了梳理归纳。     

Fretting fatigue tests on shrink-fit specimens and investigations into the strength enhancement induced by deep rolling

The shrink-fit connection undergoes fretting fatigue at the edge of the contact, where both stress concentration and micro-slip take place. A fretting test set-up with a round-shaped specimen is proposed that eliminates lateral edge contact and misalignment, and is also appropriate for deep rolling. Comparative experiments showed a notable strength improvement, induced by deep rolling, along with the beneficial effect of friction reduction due to lubrication. Multiple cracks with clear shallow paths were evident after SEM observation, thus the maximum shear stress amplitude was assumed as a correlating parameter, while the crack arrest was inappropriate especially for deep rolled specimens.     

One‐pot synthesis of self‐stabilized and carboxyl‐functionalized fluorescent poly(methyl methacrylate) microspheres covalently dyed with tris(8‐hydroquinolinato)aluminium by dispersion polymerization

The dispersion polymerization of methyl methacrylate (MMA) with fluorescent monomer tris[2‐((8‐hydroxyquinolin‐5‐yl)methoxy)ethyl methacrylate]aluminium (Al‐HQHEMA) was investigated to obtain fluorescent microspheres under varying conditions (such as composition of dispersion medium, and content of stabilizer polyvinylpyrrolidone (PVP) and Al‐HQHEMA) in methanol–water at 70 °C with 2,2′‐azoisobutyronitrile as the initiator. Fluorescent microspheres with particle size of 2.039 µm and uniformity of 0.171 were obtained under the following conditions: methanol–water, 7:3 (v/v); PVP, 15 wt% of MMA; Al‐HQHEMA solution, 1.5 mL. Maleic monoester of monomethoxyl poly(ethylene glycol) (Mal‐MPEG) was used as a comonomer to simultaneously incorporate carboxyl groups and PEG chains. With Mal‐MPEG, no aggregation was observed in the measurements of particle size and size distribution for the obtained microspheres after cleaning off PVP, indicating that self‐stabilized fluorescent microspheres were obtained. While without Mal‐MPEG, obvious aggregation was observed. The determination of surface carboxyl content using aqueous acid–base titration showed that most of the carboxyl groups of Mal‐MPEG were located on the surface of the microspheres. © 2015 Society of Chemical Industry     

Study of residual stress variation with depth of friction stir welded aluminium plates with different thicknesses

ABSTRACT

The residual stress may greatly vary through thickness due to the large temperature gradients and severe plastic deformation in depth for thick section friction stir welded plates. AA 2024-T351 plates with 6.5, 12 and 20?mm thicknesses were joined by friction stir welding to investigate the differences of residual stress variations with depth between thin and thick plates. The surface residual stresses were compared between the X-ray diffraction and contour measurements. Significant variations of stress peaks, root central residual stresses and widths of ‘M’ profiles were observed along the thickness for thick plates. The origins of the aggravated variations with depth were investigated from the temperature gradients and material flow variations through thickness.     

Failure load prediction and optimisation for adhesively bonded joints enabled by deep learning and fruit fly optimisation

Adhesively bonded joints have been extensively employed in the aeronautical and automotive industries to join thin-layer materials for developing lightweight components. To strengthen the structural integrity of joints, it is critical to estimate and improve joint failure loads effectually. To accomplish the aforementioned purpose, this paper presents a novel deep neural network (DNN) model-enabled approach, and a single lap joint (SLJ) design is used to support research development and validation. The approach is innovative in the following aspects: (i) the DNN model is reinforced with a transfer learning (TL) mechanism to realise an adaptive prediction on a new SLJ design, and the requirement to re-create new training samples and re-train the DNN model from scratch for the design can be alleviated; (ii) a fruit fly optimisation (FFO) algorithm featured with the parallel computing capability is incorporated into the approach to efficiently optimise joint parameters based on joint failure load predictions. Case studies were developed to validate the effectiveness of the approach. Experimental results demonstrate that, with this approach, the number of datasets and the computational time required to re-train the DNN model for a new SLJ design were significantly reduced by 92.00% and 99.57% respectively, and the joint failure load was substantially increased by 9.96%.     

Corrosion of hot-dip-galvanised steel and zinc alloy-coated steel in ammonia and ammonium chloride

There are many potential causes of corrosion in animal buildings. Animals exhale large quantities of moisture into the air creating high relative humidity in the building if the moisture is not properly vented. High humidity increases the potential for condensation. In addition, ammonia may be found in large quantities in animal buildings. Ammonia is released from manure and urine. In addition, ammonium chloride is used as a nitrogen source in fertilisers. In this study, the atmospheric corrosion of hot-dip-galvanised steel and zinc alloy-coated steel such as zinc–aluminium and zinc–aluminium–magnesium has been studied in atmospheres containing different levels of ammonia. Investigations have also been conducted at different levels of ammonium chloride. The results are discussed in view of the mechanisms of corrosion of zinc and zinc alloy-coated steel in ammonia and ammonium chloride-containing environments.     

Genomic Instability Is an Early Event in Aluminium-Induced Tumorigenesis

Genomic instability is generally considered as a hallmark of tumorigenesis and a prerequisite condition for malignant transformation. Aluminium salts are suspected environmental carcinogens that transform mammary epithelial cells in vitro through unknown mechanisms. We report here that long-term culture in the presence of aluminium chloride (AlCl₃) enables HC11 normal mouse mammary epithelial cells to form tumours and metastases when injected into the syngeneic and immunocompetent BALB/cByJ strain. We demonstrate that AlCl₃ rapidly increases chromosomal structural abnormalities in mammary epithelial cells, while we failed to detect direct modulation of specific mRNA pathways. Our observations provide evidence that clastogenic activity—a well-recognized inducer of genomic instability—might account in part for the transforming abilities of aluminium in mammary epithelial cells.