Sustainable disassembly line balancing model based on triple bottom line

End of life (EOL) phase of a product is receiving more attention due to increase in environmental concerns, and many studies have been conducted for value creation in EOL, focusing on concepts as remanufacturing, reuse and recycling in sustainable production manner. This study especially focuses on one of global problem, e-waste. To minimise the amount of wastes and maximise recovered materials from EOL, disassembly is one of the most important concept, associated with reuse, and balancing disassembly line in an optimal way is essential for organisations. In disassembly line balancing (DLB), not only precedence of tasks, but also risk criteria related to environment and human safety should be considered for sustainability. The aim of this study is to propose a model based on triple bottom line (TBL) dimensions, i.e. human safety, environmental safety and business criteria. To achieve sustainability in DLB, and for risk assessment in sustainable DLB, it had been decided to use a multi-criteria method, i.e. TODIM, acronym in Portuguese of ‘Tomada de Decisão Iterativa Multicritério’. The proposed model included 22 disassembly criteria categorised under TBL dimensions, which are derived from the literature. Implementation of the study was conducted for computer disassembly processes, and as a result of the study approximately 12% an improvement in cycle time was succeeded. In the long run, the integration of sustainability in disassembly operations may contribute to the competitive advantage of the company in terms of differentiation and corporate image by achieving business, environment and human targets simultaneously.     

Masking the Peroxidase-Like Activity of the Molybdenum Disulfide Nanozyme Enables Label-Free Lipase Detection

Two-dimensional MoS₂ nanoparticles (2D-nps) exhibit artificial enzyme properties that can be regulated at bio-nanointerfaces. We discovered that protein lipase is able to tune the peroxidase-like activity of MoS₂ 2D-nps, offering low-nanomolar, label-free detection and identification in samples with unknown identity. The inhibition of the peroxidase-like activity of the MoS₂ 2D-nps was demonstrated to be concentration dependent, and as low as 5 nm lipase was detected with this approach. The results were compared with those obtained with several other proteins that did not display any significant interference with the nanozyme behavior of the MoS₂ 2D-nps. This unique response of lipase was characterized and exploited for the successful identification of lipase in six unknown samples by using qualitative visual inspection and a quantitative statistical analysis method. The developed methodology in this approach is noteworthy for many aspects; MoS₂ 2D-nps are neither labeled with a signaling moiety nor modified with any ligands for signal readout. Only the intrinsic nanozyme activity of the MoS₂ 2D-nps is exploited for this detection approach. No analytical equipment is necessary for the visual detection of lipase. The synthesis of the water-soluble MoS₂ 2D-nps is low costing and can be performed in bulk scale. Exploring the properties of 2D-nps and their interactions with biological materials reveals highly interesting yet instrumental features that offer the development of novel bioanalytical approaches.     

The effect of fibre orientation of the dry sliding wear of borsic-reinforced 2014 aluminium alloy

The effect of fibre orientation on the dry sliding wear of continuous B(SiC) fibre reinforced aluminium alloy composites was investigated using a pin-on-disc wear testing machine. The metal-matrix composites (MMC) samples were tested in the normal (N), parallel (P) and antiparallel (AP) orientations sliding against a steel counter disc at a fixed speed of 1 m s^–1 under loads of from 12 to 60 N.The results showed that for the matrix alloy and MMCs, the average wear increased linearly with load. Wear of the MMCs was insensitive to fibre content but for composites with fibre contents at or above the minimum of 16 vol% used for this work, the wear rate was about 18% of that of the unreinforced matrix. Fibre orientation had a minor effect on wear rate; the N orientation gave the lowest wear rate with the AP orientation slightly higher and the P orientation significantly higher.The average coefficients of friction of the MMCs in N and AP orientations decreased linearly with increased wear rate and non-linearly with increased load, but the P orientation was insensitive to either variable.It was concluded from these results and a metallographic examination that the mechanism of wear of MMCs was essentially oxidative wear of the matrix. The hard fibres modified this to slightly different degrees depending on their orientation relative to the wear surface and sliding direction.     

Thermodynamic analysis of solar photovoltaic cell systems

The thermodynamic characteristics of solar photovoltaic (PV) cells are investigated from a perspective based on exergy. A new efficiency is developed that is useful in studying PV performance and possible improvements. Exergy analysis is applied to a PV system and its components, and exergy flows, losses and efficiencies are evaluated. Energy efficiency is seen to vary between 7% and 12% during the day. In contrast, exergy efficiencies, which incorporate the second law of thermodynamics and account for solar irradiation exergy values, are lower for electricity generation using the considered PV system, ranging from 2% to 8%. Values of “fill factors” are determined for the system and observed to be similar to values of exergy efficiency.     

Oxidation behavior of single-crystal Al2O3-fiber-reinforced Ni3Al-based composites

A series of single-crystal Al₂O₃-fiber-reinforced Ni3Al-based intermetallic matrix composites were fabricated by pressure casting. The matrices employed were binary Ni₃Al, Ni₃Al-0.5 at. pct Cr, and Ni₃Al-0.34 at. pct Zr. The development of microstructure upon oxidation in air at either 1100 °C or 1200 °C was investigated by optical, scanning, and transmission electron microscopy. In air-oxidized binary Ni₃Al, some of the fibers were fully or partially covered with a layer of oxide. A weak fiber/matrix bond in this system, which led to fiber debonding during composite processing, is believed to be responsible for the ingress of O into the composite and oxidation of the matrix in the debonded regions at the fiber/matrix interface. Addition of Cr to Ni₃Al resulted in an almost threefold increase in fiber/matrix bond strength. No oxidation of the interface was observed. A thick layer of oxide was formed around all the fibers when the composite was thermally cycled prior to isothermal annealing. Addition of Zr to Ni₃Al resulted in the formation of a layer of ZrO₂ on the surface of the fibers during composite processing. The ZrO₂ layer provided a fast path for the diffusion of O, which led to the formation of a rootlike oxide structure around the fibers. The rootlike structure consisted of a network of Al₂O₃-covered ZrO₂.     

The IFR/DFR property of the forward recurrence-time distribution

When a failure or replacement process is modeled as a renewal process, the residual life of the unit in use at a given time is generally referred to as the forward recurrence time (RT). Distributional properties of this random variable are critically important in many applications. This paper investigates the extent to which the failure-rate function monotonicity of a life distribution is inherited by the forward RT distribution at time s of its renewal process. For DFR life distributions, the forward RT distribution is also DFR for every s⩾0. However, the corresponding property does not necessarily hold for IFR life distributions. The forward RT distribution is IFR in the limit as s→0 and as s→∞. For IFR Weibull life distributions, we demonstrate numerically that the forward RT distribution is IFR for small s. As s is increased, it alternates between being IFR and non-IFR in an interesting cyclical pattern, and remains IFR beyond a large enough s     

Film morphology and reaction rate for the CVD of tungsten by the WF6—SiH4 reaction

Journal of Electronic Materials - Low pressure chemical vapor deposition (LPCVD) of tungsten (W) by SiH4 reduction of WF6 on Si(100) surfaces was studied in a single-wafer, cold-wall reactor over a...     

Salt and pepper noise filtering with fuzzy-cellular automata

A new image denoising algorithm is proposed to restore digital images corrupted by impulse noise. It is based on two dimensional cellular automata (CA) with the help of fuzzy logic theory. The algorithm describes a local fuzzy transition rule which gives a membership value to the corrupted pixel neighborhood and assigns next state value as a central pixel value. The proposed method removes the noise effectively even at noise level as high as 90%. Extensive simulations show that the proposed algorithm provides better performance than many of the existing filters in terms of noise suppression and detail preservation. Also, qualitative and quantitative measures of the image produce better results on different images compared with the other algorithms.