Analysis of modularity implementation methods from an assembly and variety viewpoints

The advent of product modularity has enabled the manufacturing firms to develop substantial product variety at lower costs and shorter lead times. Several modular design methodologies exist in the literature, but each method was developed to optimize a certain criterion. It is also not clear which method would provide the best results under a specific case, as most of these methods have not yet been compared quantitatively. This paper reviews and compares three well-known modularizing methodologies in order to determine the method generating the best modularized design. Our hypothesis for comparison is that the method offering highest ease of assembly, and accommodating design for variety to meet future customer needs, is the best. An electronic toothbrush and a bicycle are used to compare the three methodologies: (1) function heuristic method, (2) behavioral-driven function–environment–structure (B-FES) modeling framework, and (3) decomposition approach.     

Layered silicate-polymer nanocomposite coatings via radiation curing process for flame retardant applications

Polymer-clay nanocomposite (PCN) films were fabricated by uniformly dispersing organically modified montmorillonite clay (Cloisite 20A and 30B) in varying concentrations of 2%, 5%, 10% and 15% (w/w) in an optimized composition of aliphatic urethane acrylate (AUA)–Trimethylolpropane triacrylate (TMPTA) mixture by ultra-sonication followed by ⁶⁰Co-gamma radiation induced curing. Radiation doses were optimized to obtain non-tacky, homogeneous thin films, which were subsequently characterized by UV–vis spectrophotometry, X-ray diffraction (XRD), small angle X-ray scattering (SAXS), Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Gloss of the PCN films decreased, and fracture toughness and hardness of PCN films improved with the incorporation of the clay in the PCN coatings. Limiting Oxygen Indices (LOIs) of the samples were calculated from the thermogravimetric analyses data to ascertain the efficacy of the PCN films as potential flame retardant materials.     

Impedimetric biosensor based on magnetic nanoparticles for electrochemical detection of dopamine

One of the difficulties which limit the use of electrochemical sensors for detection of dopamine is the interference from ascorbic acid. We have sought to address this problem through the synthesis and characterization of a suitable electrode material based on magnetic nanoparticles. The interference from the ascorbic acid was overcome by fabricating a negatively charged electrode surface using PEGylated arginine functionalized magnetic nanoparticles (PA-MNPs). The nanoparticles were characterized by various techniques viz., X-ray diffraction, FT-Infrared spectroscopy, transmission electron microscopy and vibrating sample magnetometer. The electrochemical behavior of the proposed sensor was investigated by cyclic voltammetry and the sensor showed high sensitivity and selectivity for dopamine. The response mechanism of the modified electrode is based on the interaction between the negatively charged electrode and the positively charged dopamine. Under optimized conditions, linear calibration plots were obtained for amperometric detection of dopamine (DA) over the concentration range of 1–9 mM dopamine, with a linear correlation coefficient of 0.9836, sensitivity of 121 μA/mM and a detection limit of 7.25 μM. Electrochemical impedance spectroscopy (EIS) has been used to study the interface properties of modified electrodes. The value of the polarization resistance (R_p) increases linearly with dopamine concentration in the range of 10 μM to 1 mM and the limit of detection (LOD) was calculated to be 14.1 μM. High sensitivity and selectivity, micromolar detection limit, high reproducibility, along with ease of preparation of the electrode surface make this system suitable for the determination of DA in pharmaceutical and clinical preparations.     

Micellization, Interaction and Microenvironment in the Mixed Solution of Pluronics and Surfynol 104 with Nuclear Magnetic Resonance

The micellization, intermolecular interaction and microenvironment of molecular segments in the mixed aqueous solution of PEO-PPO-PEO triblock copolymer (Pluronic? F88, P84 and P123) and Surfynol? 104 (S104) were studied by nuclear magnetic resonance method. The results showed that the addition of S104 decreased the critical micellization temperature of copolymer. When its concentration was 0.5 g/L, the most reduction was up to more than 10℃ for F88, which was most hydrophilic in the selected copolymers. This reduction was caused by the hydrophobic interaction between S104 molecules and PPO segments. The addition of S104 enhanced the hydration of PEO segments most obviously for P123. And S104 slightly increased the hydration of PPO segments before the micellization, but obviously decreased their hydration after micellization, which was attributed to the hydrophobic interaction mentioned above and temperature rising. This effect was most observable for F88.     

Dye-sensitized solar cell based on nanocrystalline ZnO thin film electrodes combined with a novel light absorbing dye Coomassie Brilliant Blue in acetonitrile solution

In this work, characterization of dye-sensitized solar cells (DSSC) using nanocrystalline ZnO thin film electrodes combined with a novel light absorbing dye Coomassie Brilliant Blue (CBB), in acetonitrile solution is reported. The absorption spectrum of this dye in acetonitrile solution indicates appreciable absorption in the range of 500–700 nm with a sharp peak at 597 nm indicating its possible use as a photosensitizer for ZnO. The current–voltage and efficiency characteristics of a DSSC based on this dye and ZnO acceptor are measured for two methods of depositing the ZnO. Better response is achieved for nanocrystalline ZnO thin films than for sprayed films in terms of cell output.     

Study of the preparation,properties and kinetics of anion release in drug intercalated magnetic nanohybrids

We report a new magnetic nanohybrid material to make layered double hydroxides (LDHs) as a targeted drug carrier. The magnetite prepared using a modified conventional coprecipitation technique was embedded in to the fluvastatin intercalated hydrophobic anionic clay through one step process. XRD analysis shows a decrease in lattice parameter of magnetite which is due to generation of stress by the LDHs. Filtered HRTEM image indicates that the magnetic nanohybrid consists of well-defined composite structure and the diameter is around 13 nm. Further, it is shown through magnetisation and ESR study that the exchange interaction between magnetite and drug intercalated LDHs layers shifted the T_B of Fe₃O₄ in magnetic nanohybrid to lower temperatures. In vitro release study of nanohybrid particles at pH 7.4 in PBS and at 37 °C show a faster release for magnetic nanohybrids. The mechanism is probably due to combined effect of interparticle and heterogeneous diffusion via anionic exchange.     

Optimisation of osmotic dehydration process of carrot cubes in mixtures of sucrose and sodium chloride solutions

In the optimisation of the osmotic dehydration process of the carrot cubes in mixtures of sucrose and sodium chloride by response surface methodology, using face-centred central composite design (CCF), it was shown that the independent process variables for osmotic dehydration process were osmotic solution concentrations (5–15% w/v sodium chloride in 50 °Brix sucrose syrup), temperature (35–55 °C) and process duration (120–240 min). Statistical analysis of results showed that the linear terms of all the process variables have a significant effect on all the responses. The optimum osmotic dehydration process conditions for maximum water loss, minimum solute gain, maximum retention of colour, and sensory score were: 50 °Brix + 15% w/v sodium chloride solution, 54.8 °C solution temperature and 120 min process duration.     

Correction to: Deposition of bismuth sulfide and aluminum doped bismuth sulfide thin films for photovoltaic applications

Journal of Materials Science: Materials in Electronics -