The optimization of the surface roughness in the process of tangential turn-milling using genetic algorithm

Turn-milling is a relatively new process in manufacturing technology, where both the workpiece and the tool are given a rotary movement simultaneously. This paper presents an approach for optimization of cutting parameters at cylindrical workpieces leading to minimum surface roughness by using genetic algorithm in the tangential turn-milling process. During testing, the effects of the cutting parameters on the surface roughness were investigated. Additionally, by using genetic algorithms for each of the cutting parameters (depth of cut, workpiece speed, tool speed and feed rate) minimum surface roughness for the process of tangential turn-milling was determined according to the cutting parameters.     

A rare complication of hemodialysis catheters: superior vena cava syndrome

Central venous catheters in hemodialysis patients may result in superior vena cava (SVC) syndrome. With the increasing use of these catheters, the SVC syndrome will probably be more common among hemodialysis patients. This report describes 3 cases of SVC syndrome due to central venous catheters that developed in hemodialysis patients with previous multiple catheter placements.     

Development and in vitro/in vivo evaluation of dihydroergotamine mesylate loaded maltodextrin-pullulan sublingual films

Dihydroergotamine mesylate (DHE), ergotamine derivative, has been offered for clinical use to stop or treat symptoms of an emerging migraine as injection for more than a half century. It is shown that bioavailability of DHE greatly changes between the subjects and up to 99% of the orally absorbed dose may be cleared by first pass metabolism. The aim of this study was to design and optimize DHE fast-dissolving sublingual films for migraine treatment. For this purpose pullulan and maltodextrin was chosen as film-forming polymers and propylene glycol as plasticizer. For optimization process Box Behnken design was used. The formed films were free from air bubbles, cuttings, or cracks. Disintegration, mechanical strength and dissolution of films were compared. It is found that pullulan and maltodextrin formed films with the most desired properties at the concentration of 1.5% and 2%. The application of optimum formulation to rabbits showed that bioavailability of formulation is about 23.35% with a t_max 20?min. Due to this fast onset of action and higher bioavailability than oral administration, it is suggested that the polymer combinations of pullulan and maltodextrin formed successful films and were considered as an alternative dosage form for DHE in migraine therapy.     

Ambient volatile organic compound (VOC) concentrations around a petrochemical complex and a petroleum refinery

Air samples were collected between September 2000 and September 2001 in Izmir, Turkey at three sampling sites located around a petrochemical complex and an oil refinery to measure ambient volatile organic compound (VOC) concentrations. VOC concentrations were 4-20-fold higher than those measured at a suburban site in Izmir, Turkey. Ethylene dichloride, a leaded gasoline additive used in petroleum refining and an intermediate product of the vinyl chloride process in the petrochemical complex, was the most abundant volatile organic compound, followed by ethyl alcohol and acetone. Evaluations based on wind direction clearly indicated that ambient VOC concentrations measured were affected by the refinery and petrochemical complex emissions. VOC concentrations showed seasonal variations at all sampling sites. Concentrations were highest in summer, followed by autumn, probably due to increased evaporation of VOCs from fugitive sources as a result of higher temperatures. VOC concentrations generally increased with temperature and wind speed. Temperature and wind speed together explained 1-60% of the variability in VOC concentrations. The variability in ambient VOC concentrations that could not be explained by temperature and wind speed can be attributed to the effect of other factors (i.e. wind direction, other VOC sources).     

Erratum to: Multi-scale directional-filtering-based method for follicular lymphoma grading

A new decision-based algorithm has been proposed for the restoration of digital images which are highly contaminated by the saturated impulse noise (i.e., salt-and-pepper noise). The proposed denoising algorithm performs filtering operation only to the corrupted pixels in the image, keeping uncorrupted pixels intact. The present study has used a coupled window scheme for the removal of high density noise. It has used sliding window of increasing dimension, centered at any pixel and replaced the noisy pixels consecutively by the median value of the window. However, if the entire pixels in the window are noisy, then the dimension of sliding window is increased in order to obtain the noise-free pixels for median calculation. Consequently, this algorithm has been found to be able to remove the high density salt-and-pepper noise and also preserved the fine details of the four images, Lena, Elaine, Rhythm, and Sunny, used as test images in this study (The latter two real-life images have been acquired using Sony: Steady Shot DSC- S3000). Experimentally, it has been found that the proposed algorithm yields better peak signal-to-noise ratio, image enhancement factor, structural similarity index measure and image quality index, compared with the other state-of-art median-based filters viz. standard median filter, adaptive median filter, progressive switched median filter, modified decision-based algorithm and modified decision-based unsymmetric trimmed median filter.     

Zero-Displacement Lateral Spreads, 1999 Kocaeli, Turkey, Earthquake

Three potential lateral spreads exhibited negligible displacements during the 1999 Kocaeli, Turkey Earthquake (Mw = 7.5) even though they were located within 7?km of the fault rupture. These spreads are analyzed to verify and augment current procedures for predicting liquefaction resistance and lateral spread displacement. The sites include ?ark Canal and Cumhuriyet Avenue in Adapazari, underlain by fine-grained sediment, and Degirmendere Nose adjacent to Izmit Bay, a steeply sloping area underlain by moderately dense silty sand. The plasticity index and moisture content criteria of Bray and Sancio set forth in 2006 indicate that much of the fine-grained sediment is liquefiable. Even though liquefaction likely occurred, lateral spreading did not occur due either to the dilative nature of fine-grained, sandlike sediments or the inherent strength of claylike sediments. Corrected blow counts, (N1)60, in moderately dense sand at Degirmendere Nose range from 15 to 25 blows/30?cm, indicating that liquefaction should have occurred but that the silty sand was too dense and dilative to deform. This finding is consistent with the MLR procedure of Youd et al. set forth in 2002 that identifies liquefiable sands with (N1)60 greater than 15 blows/30?cm as resistant to lateral spread during earthquakes with M<8.     

Experimental investigation of cutting parameters in machining of 100Cr6 with tangential turn-milling method

The turn-milling methods for machining operation have been developed to increase efficiency of conventional machines recently. These methods are used especially by coupling some apparatuses on the computer numerical control (CNC) machine to decrease the production time and machine costs, ensure the maximum production and increase the quality of machining. In this study, 100Cr6 bearing steel extensively used in industry has been machined by tangential turn-milling method. This paper presents an approach for optimization of the effects of the cutting parameters including cutter speed, workpiece speed, axial feed rate, and depth of cut on the surface roughness in the machining of 100Cr6 steel with tangential turn-milling method by using genetic algorithm (GA). Tangential turning-milling method has been determined to have optimum effects of cutting parameters on the machining of 100Cr6 steel. The experimental results show that the surface roughness quality is close to that of grinding process.     

Novel polySchiff base containing naphthyl: synthesis,characterization, optical properties and surface morphology

In the present work, a Schiff base was obtained from reaction of 1-naphthylamine with salicylaldehyde and its polymer (poly(NIMP)) was synthesized via oxidative polycondensation. The characterizations of the synthesized Schiff base and poly(NIMP) were determined by ¹H NMR, ¹³C NMR, FT-IR, GPC and TGA techniques. The film of synthesized poly(NIMP) was prepared. The film thickness was found to be 106 μm. The optical band gap (E_g) values of the film were determined by UV-vis spectroscopy. Direct, indirect and forbidden indirect band gap (E_gd, E_gid and E_gfid) values of the film were found as 1.698, 1.223 and 1.461 eV, respectively. Surface properties of the film were investigated by Atomic force microscope (AFM). In the AFM results, the average surface roughness and average square root roughness were obtained as 2.46 and 3.79 nm, respectively. A negative skewness value exhibited dominant valleys while the high kurtosis value exhibited spiky features.     

Manipulation at optimum locations for maximum force transmission with mobile robots under environmental disturbances

Autonomous Robots - Remote manipulation plays a key role for applications in hazardous conditions, yet designing a robust controller enabling safe interaction with unknown environment and under the...     

A low,particle‐sized,nonporous support for enzyme immobilization: Uniform poly(glycidyl methacrylate) latex particles

The uniform and nonporous poly(glycidyl methacrylate) (poly(GMA)) latex particles, 1.7 μm in size, were first tried as a support in enzyme immobilization. For this purpose, α‐chymotrypsin (CT) was selected as the model enzyme. The low particle size and nonporous character of the selected support allowed to carry out the enzyme–subtrate interaction on a sufficiently large surface area (3.36 m²/g) and in the absence of intraparticular diffusion limitations. This property is particularly important when the immobilized CT is used for the substrates with high molecular weights (i.e., proteins). The latex particles were synthesized by dispersion polymerization of GMA. The reactive character of poly(GMA) allowed the direct attachment of primary amine groups onto the particles. Confocal laser scanning microscopy (CLSM) showed that primary amine groups were preferentially located on the particle's surface. Hence, the selected enzyme, CT was immobilized on the surface of nonporous particles via glutaraldehyde activation. For CT‐immobilized poly(GMA) particles, the maximum activity (r_m) and Michealis constant (K_m) were found to be 17.2 μmol/mg CT min and 121.6 μm, respectively. No significant loss was observed in the activity of immobilized CT, during the course of experiments. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 818–824, 2006