The Role of Fuzzy and Genetic Algorithms in Part Family Formation and Sequence Optimisation for Flexible Manufacturing Systems

Group technology (GT) is one of the key issues in the successful implementation of flexible manufacturing systems (FMSs). The success of GT implementation is in the effective formation of part families (PFs) and similarity coefficients measures. Over the past three decades, many similarity coefficients have been proposed, but a better similarity coefficient measure is required. The decision-making process in a manufacturing system often involves uncertainties and ambiguities. Under such circumstances, fuzzy methodologies have proved to be an effective tool for taking fuzziness into consideration. The first part of this paper deals with the fuzzy part-family formation. This was achieved in the following ways: 1. A new similarity coefficient measure has been developed and this coefficient measure is used to form a part-family. 2. A mathematical model that uses this similarity coefficient for solving the part-family formation problems optimally in an FMS is developed. The fuzzy approach has the special advantage of producing more accurate results than conventional clustering and other methods. It not only reveals the specific part family that a part belongs to, but also provides the degree of membership of a part associated with each part family. This will give a balanced work load for the machine. In the second part of this paper, the introduction of the concept of genetic algorithms is proposed to eliminate more job sequences and, finally, the optimum sequence is obtained through the minimum penalty cost. Software is developed and implemented to obtain an optimum sequence and, finally, a numerical example is given as an illustration.     

Thin magnetic films of Sm-Co nanocrystallites exploiting spin coating deposition

Thin magnetic films of Sm-Co nanocrystallites on SiO₂ substrate were fabricated using spin coating deposition. In a typical synthesis, precursor of Sm-Co oleate complex was spin coated onto a SiO₂ substrate in the form of precursor films and subsequently they were subjected to reductive annealing at 773 K for 2 h, so as to crystallize Sm-Co phase in the films. It has been found that the reductive annealing temperature (573-773 K) played a critical role on the nucleation and formation of Sm-Co crystalline phases; while the spinning speed (3000-5000 rpm) has a significant effect in controlling the film thickness, which in turn affects the particle diameter, inter-particle distance and packing density of the Sm-Co nanocrystallites. Coercivity values of 27.9, 23.9 and 18.7 kA⋅m^− 1 and magnetization values of 2.89, 2.51 and 2.21 × 10^− 6 A⋅m² were achieved for the Sm-Co films with thicknesses of 345 (3000 rpm), 264 (4000 rpm) and 162 nm (5000 rpm), respectively. Further, these hard magnetic properties could be significantly improved by subjecting the Sm-Co films to post-annealing at 873 K.     

Antiferromagnetism and the Effect of Exchange Bias in LaCr1−x Fe x O3 (x=0.40 to 0.60)

LaCr_1?x Fe _x O₃ (x=0, 0.4, 0.45, 0.6 and 1.0) have been prepared in single phase form with Pbnm space group. The x=0 sample exhibits antiferromagnetic (AFM) transition at Néel temperature T _N =290 K and it is found to reduce with increase in doping concentration up to x=0.45. Magnetization reversal below a compensation temperature of 100 K was observed in the x=0.45 sample and it is explained in terms of competition between two AFM interactions and associated magnetic anisotropy. Exchange bias was observed in the x=0.45 sample and the temperature dependence of exchange bias field and vertical magnetization shift were analyzed.     

Resource settings have a major influence on the outcome of maintenance hemodialysis patients in South India

Chronic kidney disease is reaching epidemic proportions and the number of patients on renal replacement therapy (RRT) is increasing worldwide and also in developing countries. To meet the challenge of providing RRT, a few charity organizations provide hemodialysis units for underprivileged patients, as the private hospitals are unaffordable for the majority. There is a paucity of information on the outcome of dialysis in these patients. Here, we describe the outcome of hemodialysis patients comparing the middle‐ and upper‐class income group with the lower class income group. A retrospective analysis was carried out in 558 CKD patients initiated on maintenance hemodialysis in two different dialysis facilities. Group A (n=247) included those who belonged to the lowermost socioeconomic status and were undergoing dialysis in two nonprofit, charity (TANKER)‐run dialysis units, and Group B (n=311) was undergoing dialysis in a nonprofit hospital setting where no subsidy was given. Those patients of a low socioeconomic status, especially those who are diabetics, have a higher death rate (Group A‐38.1%, Group B‐4.2%) and loss to follow‐up (Group A‐25.9%, Group B‐0.3%) compared with those who are in the middle‐ and high‐income group. Higher EPO use and hence higher hemoglobin levels (Group A‐6.4±1.2, Group B‐8.9±1.5 P<0.001) were observed in those who were in the middle and the higher income group. Lower serum phosphorus level was observed in the low‐socioeconomic group (Group A‐4.7±1.5, Group B‐5.5±1.9, P<0.001). Patients belonging to the middle and higher socioeconomic group undergo more transplantations compared with the lower socioeconomic group (Group A‐2.4%, Group B‐65.6%).     

Experimental f″ of As at 170, 200, 250 and 300 K from the Bijvoet pairs of GaAs

Anomalous dispersion effects lead to the modification of the measured X-ray structure factors. In this work, we have determined the imaginary part of the anomalous dispersion correction terms (f″) of arsenide atom (As), through the X-ray data collected using spherical single crystal of GaAs, at various temperatures, i.e. 170, 200, 250 and 300 K. It is stressed that more measurements off″ of the elements are needed to confirm the theoretical calculations.     

Evaluation of micro-mechanical properties of nonlinear cementitious composite using large-displacement transient nanoindentation analysis

Nanoindentation technique is employed for evaluation of mechanical properties of homogeneous materials at micro-level. Many engineering materials, especially cement and concrete composites, which are extensively used as building materials, exhibit phase heterogeneity and are highly porous. The presence of pores highly influences the response obtained from nanoindentation tests. In this study, mechanical properties of Calcium-Silicate-Hydrate (C-S-H), the primary binding agent in cementitious composites, are investigated using a simulated nanoindentation technique. The influence of presence of pores and its geometrical distribution on the non-linear response of C-S-H phases and the stress distribution are critically analysed.     

Emission reduction on ethanol–gasoline blend using cerium oxide nanoparticles as fuel additive

In this study, the effect of ethanol–gasoline blend with cerium oxide nanoparticles as additive on a Tata Nano twin–cylinder SI engine was investigated. In this work, the combustion, performance and emission tests were conducted. The experiment fuels were prepared using 99.9% pure ethanol and gasoline with cerium oxide nanoparticles. The volumetric percentages of ethanol–gasoline blends with cerium oxide nanoparticles additive are in the ratio of E30, E40 and E50. These represent the ratios of ethanol amount in the total blend and the rest of gasoline. Additionally, 100?mg, 150?mg and 200?mg cerium oxide nanoparticles additive are mixed to E30, E40 and E50, respectively. The venture of this investigation was to reformulate the fuel to utilize the cerium oxide nanoparticles with ethanol and gasoline blend to develop the fuel’s performance and to decrease the pollution from the engine. The experimental results expose an increase in brake thermal efficiency for the nanoparticles blends. In the emission test CO, CO₂, HC and NOx are noticeably reduced, and O₂ increased for all the blends. In combustion analyses, the cylinder pressure is higher for nanoparticles blends, when compared to that of the sole fuel.     

Flow reduction in high‐flow arteriovenous fistulas improve cardiovascular parameters and decreases need for hospitalization

High output heart failure (HF) and pulmonary hypertension have been demonstrated in patients with prevalent arteriovenous (AV) fistulas. Fistulas with flow >2000 mL/minutes are more likely to induce changes in cardiac geometry and pulmonary artery pressure. The effects of reducing flow in AV access and its implications on HF decompensation and hospitalizations have not been studied. Retrospective analysis of 12 patients who needed hospitalization for acute Congestive Heart Failure (CHF) decompensation with AV access flow of 2 L/minutes (as defined by Kidney Disease Outcomes Quality Initiative (KDOQI)) or more were included in the study. All the patients underwent banding of their inflow at the anastomosis with perioperative access flow measurement. Follow‐up period was 6 months. 2D echo was done at 6 months postbanding in addition to access flow and clinical evaluation. Complete data was available for all the 12 patients. Study data was collected on all the 12 patients. Mean age was 64.7 years. The mean access flow pre and postbanding were 3784 mL/minutes and 1178 mL/minutes, respectively (P < 0.001). Eighty percent of the patients had diabetes and 41% had coronary artery disease. There was a statistically significant decrease in cardiac output (pre = 7.06 L/minutes, post = 6.47 L/minutes P = 0.03), pulmonary systolic pressure (pre = 54 mmHg, post = 44 mmHg P = 0.02), left ventricular mass index (LVMI) (pre = 130 g/m², post = 125 g/m² P = 0.006) and need for rehospitalization for CHF decompensation. The New York Heart Association (NYHA) staging improved by 1 stage postbanding (P = 0.002). The hospitalization rate was 3.75 ± 1.2 in the 6 months before banding and was decreased to 1.08 ± 1.2 (P = 0.002) postbanding. The hemoglobin level, predialysis systolic blood pressure, calcium phosphorous product and the use of Renin Angiotensin Aldosterone System (RAAS) blockade agents and calcium channel blockers were comparable before and after inflow banding. Flow reduction in high flow fistulas are associated with decreased LVMI and pulmonary artery pressures. There is also a significant reduction in the risk for hospitalization due to acute HF and an improvement in NYHA heart failure stage.     

On the optical and electrical properties of rf and a.c. plasma polymerized aniline thin films

Polyaniline is a widely studied conducting polymer and is a useful material in its bulk and thin film form for many applications, because of its excellent optical and electrical properties. Pristine and iodine doped polyaniline thin films were prepared by a.c. and rf plasma polymerization techniques separately for the comparison of their optical and electrical properties. Doping of iodine was effectedin situ. The structural properties of these films were evaluated by FTIR spectroscopy and the optical band gap was estimated from UV-vis-NIR measurements. Comparative studies on the structural, optical and electrical properties of a.c. and rf polymerization are presented here. It has been found that the optical band gap of the polyaniline thin films prepared by rf and a.c. plasma polymerization techniques differ considerably and the band gap is further reduced byin situ doping of iodine. The electrical conductivity measurements on these films show a higher value of electrical conductivity in the case of rf plasma polymerized thin films when compared to the a.c. plasma polymerized films. Also, it is found that the iodine doping enhanced conductivity of the polymer thin films considerably. The results are compared and correlated and have been explained with respect to the different structures adopted under these two preparation techniques.     

Nano‐zero valent iron impregnated cashew nut shell: a solution to heavy metal contaminated water/wastewater

The present research is focused on the removal of Zn(II) ions from aqueous solution using nano zero‐valent iron impregnated cashew nut shell (NZVI‐CNS). The present system was investigated in batch mode operation. NZVI‐CNS was prepared by the liquid‐phase reduction process. The results showed that the NZVI‐CNS exhibited superior adsorption capacity for the removal of Zn(II) ions. Adsorption isotherm and kinetic models were applied to explain the nature of the adsorption process. Adsorption kinetic data followed the pseudo‐first order kinetic model. Moreover, the equilibrium adsorption data were best fitted with a Freundlich model. Langmuir monolayer adsorption capacity was calculated as 94.46 mg of Zn(II) ions/g of NZVI‐CNS. The thermodynamic parameters explain that the present adsorption system was measured as feasible and spontaneous. This newly prepared adsorbent can be successfully applied for the different industrial wastewater treatment. Finally, the exploration asks about contemplated that NZVI‐CNS has exhibited unrivalled adsorption limit. Additionally, NZVI‐CNS is believed to be extremely green and monetarily neighbourly help for wastewater treatment. The results indicate that the feasible approach could be applied in agricultural waste biomass materials for the productive expulsion of heavy metals from aqueous solution and reusing agricultural wastes to facilitate their disposal problem.Inspec keywords: wastewater treatment, contamination, zinc, reduction (chemical), adsorption, monolayers, renewable materialsOther keywords: nano zero‐valent iron impregnated cashew nut shell, aqueous solution, Zn(II) ion removal, NZVI‐CNS, batch mode operation, liquid‐phase reduction process, adsorption capacity, adsorption isotherm models, adsorption kinetic models, adsorption kinetic data, adsorption process, pseudo‐first order kinetic model, equilibrium adsorption data, Freundlich model, Langmuir monolayer adsorption capacity, thermodynamic parameters, adsorption system, industrial wastewater treatment, agricultural waste biomass materials, productive expulsion, heavy metals, waste disposal, Zn