Feature-based rule induction in machining operation using rough set theory for quality assurance

There have been many studies, mainly by the use of statistical modeling techniques, as to predicting quality characteristics in machining operations where a large number of process variables need to be considered. In conventional metal removal processes, however, an exact prediction of surface roughness is not possible or very difficult to achieve, due to the stochastic nature of machining processes. In this paper, a novel approach is proposed to solve the quality assurance problem in predicting the acceptance of computer numerical control (CNC) machined parts, rather than focusing on the prediction of precise surface roughness values. One of the data mining techniques, called rough set theory, is applied to derive rules for the process variables that contribute to the surface roughness. The proposed rule-composing algorithm and rule-validation procedure have been tested with the historical data the company has collected over the years. The results indicate a higher accuracy over the statistical approaches in terms of predicting acceptance level of surface roughness.     

X-ray investigation of a domestic refrigerator. Observations at 25°C ambient temperature

In this study, the transient behavior of a domestic refrigerator is investigated by the use of an X-ray system. The studies are made on a two-door upright freezer with a volume of 435 liters, and which has an automatic defrost feature. The refrigerant is R134a. During the experimental study, ambient temperature is held at 25±2 °C. Real time X-ray video images of the refrigeration circuit are taken during the pull-down (cooling down of the refrigerator from ambient temperature) and cyclic periods as well. X-ray images are recorded by focusing to on the dryer, capillary exit, evaporator inlet, and accumulator regions specifically. In order to watch evaporator and dryer sections continuously, two identical experiments are made while the probe is focused on either the evaporator or dryer sections each time. By matching the video images and temperature data, the flow regimes, charge inventory, accumulator functioning, and changes of subcooling degree at dryer inlet are explained. Possible flow induced noise mechanisms are identified.     

Structural analysis of polymer end groups by electrospray ionization high-energy collision-induced dissociation tandem mass spectrometry

Chemical structures of polymer end groups play an important role in determining the functional properties of a polymeric system. We present a mass spectrometric method for determining end group structures. Polymeric ions are produced by electrospray ionization (ESI), and they are subject to source fragmentation in the ESI interface region to produce low-mass fragment ions. A series of source-fragment ions containing various numbers of monomer units are selected for high-energy collision-induced dissociation (CID) in a sector/time-of-flight tandem mass spectrometer. It is shown that high-energy CID spectra of source-induced fragment ions are very informative for end group structure characterization. By comparing the CID spectra of fragment ions with those of known chemicals, it is possible to unambiguously identify the end group structures. The utility of this technique is illustrated for the analysis of two poly(ethylene glycol)-based slow-releasing drugs where detailed structural characterization is of significance for drug formulation, quality control, and regulatory approval. Practical issues related to the application of this method are discussed.     

Assessment of the molecular weight distribution of tannin fractions through MALDI-TOF MS analysis of protein-tannin complexes

An innovative mass spectrometry method was developed for determining mass distributions of tannin fractions that cannot be approached through direct MALDI-TOF analysis. It was applied to three procyanidin fractions with average degrees of polymerizations = 3, 9, and 28, respectively, and one gallotannin fraction (Tara tannin). The proposed approach consists of MALDI-TOF analysis of the soluble complexes formed between these tannin fractions and bovine serum albumin (BSA). Complexes were detected as an unresolved "hump" following the BSA signal, and spectra were mathematically processed to determine the parameters relative to the protein-tannin complexes, which are the number-average molecular weight (Mn), the weight-average molecular weight (Mw), and the polydispersity index (PI) for each tannin fraction. Regarding condensed tannins, results are consistent with those of the standard method (thiolysis followed by HPLC separation) for all tested fractions. The method was successfully applied to a hydrolyzable tannin fraction but no standard method is available for comparison.     

A robust power flow model for active power flow control via thyristor‐controlled series compensator

In this paper, a new power flow model for active power flow control through a thyristor‐controlled series compensator (TCSC) in an AC network system is proposed. The proposed power flow model is based on the Newton–Raphson method. In this model, TCSC's admittance effect is included as a state variable into the Jacobian matrix to avoid the divergence problem. Unlike similar studies in the literature, TCSC's admittance is ignored in the bus admittance matrix, and the need for rebuilding the bus admittance matrix in each power flow iteration caused by the change of TCSC's admittance is prevented. So, faster convergence for power flow calculation is achieved. For this aim, new power equations are obtained. Also, in the proposed approach, we need not consider each terminal of TCSC as an individual bus in the power flow calculation. Thus, increasing the Jacobian and bus admittance matrixes sizes caused by the total bus number is prevented. The proposed approach is tested on an IEEE 57‐bus test system. The obtained results prove that this approach provides efficient, reliable, and fast convergence. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Effects of nonreactive resins on the properties of a UV-curable methacrylated urethane resin

The effects of two nonreactive conventional-type resins, a bisphenol-A-based phenoxy resin PAPHEN-301 and aromatic-based PETROLEUM RESIN, on the mechanical, thermal, and physical properties of methacrylated urethane resin-based UV-curable formulations were studied. A methacrylated urethane prepolymer was synthesized from isocyanatoethyl methacrylate (IEM) and polytetrahydrofurandiol (PTHF) via a one-step reaction. An increase in PAPHEN-301 content caused an increase both in tensile strength and elongation values of UV-cured polymeric films. On the other hand, an increase in PETROLEUM RESIN content caused a decrease both in tensile strength and elongation values of the polymeric films. However, thermooxidative properties were not affected by the introduction of either resin. It was also found that the water-absorption capacities of the UV-cured methacrylated urethane films depended on the type and amount of the nonreactive resins. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1837–1845, 1998     

A flexible textile structure based on polymeric photovoltaics using transparent cathode

This paper presents results for photovoltaic performance obtained from the application of different bulk heterojunction blends onto flexible polypropylene (PP) substrates for textile applications. Organic photovoltaic devices were fabricated onto non-transparent PP tapes and ITO coated glasses. The layer of poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) and PEDOT:PSS with 100 nm of silver (Ag) metal layer constituted anode structure and substituted indium tin oxide (ITO) layer in this study. The blends of poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)-propyl-1-phenyl(6,6)C₆₁ (P3HT:PCBM) or poly [2-methoxy-5-(3′,7′-dimethyloctyloxy)-1-4-phenylene vinylene] and 1-(3-methoxycarbonyl)-propyl-1-phenyl(6,6)C₆₁ (MDMO-PPV:PCBM) were utilized as the absorbing materials. The thin metal layers of lithium fluoride (LiF) and aluminum (Al) were deposited on top of the devices by evaporation. All photovoltaic devices were characterized by measuring current–voltage (I–V) characteristics under simulated AM 1.5 conditions. The morphology of these devices using MDMO-PPV:PCBM and P3HT:PCBM blends was also investigated using atomic force microscopy (AFM).     

Virulence properties of extended spectrum β-lactamase-producing Klebsiella species in meat samples

The present study was carried out to identify virulence properties (siderophores, serum resistance, and hemolysin) and antibiotic resistance in extended spectrum β-lactamase (ESBL)-producing Klebsiella isolates from 60 calf and chicken meat samples purchased from various supermarkets in Ankara, Turkey. Of the 45 Klebsiella isolates, 24 (53%) were identified as K. oxytoca and 21 (47%) were identified as K. pneumoniae. A high proportion of Klebsiella isolates had virulence factors such as hemolytic activity (67%), siderophore production (44%), and serum resistance (38%). The double-disk synergy test was used to determine ESBL production. ESBL production was detected in 13 (29%) of the 45 Klebsiella isolates. Resistance to 14 antimicrobials was tested in all Klebsiella isolates by the disk diffusion method. All isolates were resistant to two or more antimicrobial agents. All ESBL-producing Klebsiella isolates were highly resistant to cephalosporins and monobactams. Our findings indicate that meat and its products represent potential hazardous sources of multidrug-resistant and virulent Klebsiella species.