Different Evolutions of the Microstructure,Texture, and Mechanical Performance During Tension and Compression of 316L Stainless Steel

Metallurgical and Materials Transactions A - The tensile and compressive behaviors of 316L stainless steel at room temperature were compared. The differences between the stress–strain...     

Implementing and sustaining lean processes: the dilemma of societal culture effects

Lean processes allow the elimination of waste and the resulting improvements in productivity. However, implementing and sustaining lean processes are easier in some organisations than in others. There may be societal culture differences, as the successes in initial implementation in Japan have not been followed by global success. As organisations accelerate their lean efforts to gain or maintain competitive advantage, studying societal cultural effects seems timely. Understanding of the societal culture that the firm or subsidiary is operating in would be useful in determining how lean processes should lead the effort. Using the cultural dimensions developed by Hofstede, we examine the interconnection of societal culture and lean processes. For example, a societal emphasis on individualism is positively associated with a high level of lean process adoption, in terms of individual employee involvement, individual creativity and firm efficiency. A societal emphasis on high uncertainty avoidance is positively associated with a high level of lean process adoption, in terms of control and standardisation, efficiency and long-term philosophy. A societal emphasis on high power distance is positively associated with a high level of lean process adoption, in terms of control and standardisation, and efficiency. A long-term orientation in the society will be positively associated with a high level of lean process adoption, in terms of all of the dimensions. A societal emphasis on femininity will be positively associated with a high level of lean process adoption, in terms of employee involvement, creativity and long-term philosophy.     

Sustainable biodegradable coffee grounds filler and its effect on the hydrophobicity,mechanical and thermal properties of biodegradable PBAT composites

Poly(butylene adipate‐co‐terephthalate) (PBAT) and coffee grounds (CG) wastes are biodegradable materials. The high cost of PBAT restricts its marketability; the lignocellulosic CG were used as a reinforcing agent for PBAT. Thus, the present work focuses mainly on the preparation and characterization of bio‐based PBAT composites filled with CG bio‐additives with affordable cost, and with potential use in a variety of eco‐friendly fields such as packaging, biomedical devices, and composting. The PBAT polymer was melt blended with various contents of CG powder using twin screw extrusion. The compatibility and dispersion state of investigated biocomposites in presence or absence of PEG as plasticizer were investigated by using scanning electron microscopy (SEM) and X‐ray diffraction (XRD). The effect of the addition of PEG on PBAT/CG was characterized by differential scanning calorimetry (DSC), tensile properties, contact angle measurements, and thermogravimetric analysis. The chemical interaction between hydroxyl groups of CG particles and PEG plasticizer was achieved by these techniques. A pyrolysis kinetic model was proposed to identify the kinetic parameters of the thermal degradation of PBAT and CG powder. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44498.     

Iron (II) chloride catalyzed emulsion polymerization of methyl methacrylate using different initiators

The emulsifier and emulsifier-free emulsion polymerization of methyl methacrylate (MMA) using sodium bisulphite, acetaldehyde sodium bisulphite (ACSB), octyladehyde sodium bisulphite (OSB), benzaldehyde sodium bisulphite (BSB), and acetone sodium bisulphite (ASB) as different initiators, and dodecyl benzene sodium sulphonate (DBSS) as an emulsifier, were carried out at 30, 40, and 50°C. The effect of iron (II) chloride on the rate of polymerization and on the viscosity-average molecular weight was investigated. The effect of temperature, iron (II) chloride, and the type of initiator on the tacticity of the obtained polymers was investigated by means of nuclear magnetic resonance (NMR) spectroscopy. The effect of iron (II) chloride and the four carbonyl adducts (ACSB, OSB, BSB, and ASB) on the volume-average diameter and the number of polymer particles per unit volume was investigated. It was found that iron (II) chloride has a pronounced catalytic effect on the emulsion polymerization. The initiating powers of the four carbonyl adducts, ACSB, BSB, OSB, and ASB, were found to be 3.27, 0.6, 1.78, and 0.23, respectively. The rate of emulsion polymerization and viscosity-average molecular weight were found to be dependent on the emulsifier concentration, initiator type and concentration, temperature, and amount of the catalyst (FeCl₂). © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1725–1738, 1998     

Synthesis and characterization of highly porous poly(methacrylic‐co‐triethylene glycol dimethacrylate) by suspension polymerization

Porous poly(methacrylic‐co‐triethyleneglycol dimethacrylate) (MAA‐3G) was prepared by suspension polymerization using benzoyl peroxide as an initiator, poly(vinyl alcohol) as a protective colloid, and n‐hexane as a porogenic agent. The prepared polymer was base hydrolysed using hydroxyl amine and sodium methoxide into the corresponding polyhydroxamic acid (HYOX). The metal binding behavior of polyhydroxamic acid with various metal ions, the effect of pH on the metal ion capturing, and the selectivity of the resin towards the different metal ions were also examined by means of atomic absorption spectrophotometer. The thermal stability of the prepared base‐hydrolysed polymer and the metal polymer complex was examined by thermal gravimetric analysis (TGA) and differential scanning calorimeter (DSC). The prepared porous polymer methacrylic‐co‐triethyleneglycol dimethacrylate and its different modulated forms were characterized by means of FTIR specroscopy and scanning electron microscope. The hydroxamic acid content was also examined by elemental analysis. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 149–159, 1999     

Wear resistance of δ-type aluminafibre reinforced Al-4% Cu matrix composite

The wear behaviour of Al-4% Cu alloy and its composite containing-type alumina fibres has been studied at roomtemperature and at 150°C, using a standard pin-on-ringtribometer. The results show higher wear resistance and a lowercoefficient of friction for the composite material as comparedwith the matrix alloy. Three wear mechanisms of the matrix alloytested at room temperature were observed: oxidation-induceddelamination, seizure and subsequent wear due to surfacemelting. At 150°C, however, the matrix wear is due toseizure and melting. In the case of the composite material,different wear mechanisms were found: at low loads, oxidation-induced delamination was predominant, changing to high-strain-induced delamination at higher loads up to 80 N; at high loads(beyond 120 N) sub-surface delamination was the prevailingmechanism.     

铁对粉末冶金法制备铝基复合材料微观组织和力学性能及磁学性能的影响(英文)

研究铁对粉末冶金法制备铝基复合材料微观组织、力学性能及磁学性能的影响。利用机械混合制备含0,5%,10%和15%Fe(质量分数)的铝基复合材料。Al-Fe混合粉末经压制后在真空炉中600°C烧结1 h。XRD结果表明:在含有5%和10%Fe的试样中只有Fe和Al的衍射峰,而含有15%Fe的试样中则存在Al和Al13Fe4的衍射峰。实验结果表明:随着Fe含量的增加,材料的致密度和导热性变差。复合材料中的Fe可以提高其强度和硬度。材料的强化机制包括基体的晶粒细化,Fe颗粒的均匀分布以及Al13Fe4金属间化合物的形成。含有5%Fe试样的磁化强度为0.3816×10-3A·m2/g,对于含有10%Fe的试样,其磁化强度增加至0.6597×10-3A·m2/g,而对于含有15%Fe试样,其磁化强度降低至0.0702×10-3A·m2/g。这是由于在高铁试样中形成了反磁性的Al13Fe4金属间化合物导致磁化强度降低。     

Antibacterial activity of cationically modified cotton fabric with carboxymethyl chitosan

A water‐soluble carboxymethyl chitosan was prepared with a view to develop a multifunctional finish on cotton. Carboxymethyl chitosan (CMCTS) was synthesized by chemical reaction of chitosan with monochloroacetic acid under alkaline condition. The water soluble CMCTS was applied to cationized cotton with different concentrations. The treated fabrics were characterized through monitoring the textile physical properties and for the antibacterial activity against Escherichia coli DSMZ 498 and Micrococcus luteus ATCC 9341. The results obtained show that the physical properties of the treated fabrics are improved by increasing the CMCTS concentration, as well as the antibacterial activity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Prediction of sediment inflows to Angereb dam reservoir using the SRH‐1D sediment transport model

Angereb Dam, located in Ethiopia, was constructed in early 1994 as a water supply for the town of Gondar up to the year 2020. The reservoir could not achieve this objective, however, because of significant sedimentation problems. Accordingly, one objective of this study was to simulate the historical reservoir sedimentation pattern, as well as predict the near future (until 2015) sedimentation pattern of Angereb Reservoir. The Sedimentation and River Hydraulics one‐dimensional model (SRH‐1D), version 2.6, was used for this purpose. Another objective was to propose possible mitigation measures to reduce the quantity and rate of sedimentation in the reservoir. There was generally good agreement between measurements and model simulations, with the observed trends being well simulated. The exception was that the model tended to overpredict the sediment deposition volumes in the upstream reaches of the reservoir. The two mitigation alternatives for addressing the sedimentation problem, namely managing sediments in the watershed and flushing sediment through the dam bottom outlet, appear to be technically feasibility, with a predicted reduction of the volume of deposited sediment between 63 and 80% be achievable.