Stencil Nano Lithography Based on a Nanoscale Polymer Shadow Mask: Towards Organic Nanoelectronics

A stencil lithography technique has been developed to fabricate organic-material-based electronic devices with sub-micron resolution. Suspended polymethylmethacrylate ( PMMA) membranes were used as shadow masks for defining organic channels and top electrodes. Arrays of pentacene field effect transistors (FETs) with various channel lengths from 50 mu m down to 500 nm were successfully produced from the same batch using this technique. Electrical transport measurements showed that the electrical contacts of all devices were stable and the normalized contact resistances were much lower than previously studied organic FETs. Scaling effects, originating from the bulk space charge current, were investigated by analyzing the channel-length-dependent mobility and hysteresis behaviors. This novel lithography method provides a reliable means for studying the fundamental transport properties of organic materials at the nanoscale as well as enabling potential applications requiring the fabrication of integrated organic nanoelectronic devices.open1155sciescopu

A study of removal of Pb heavy metal ions from aqueous solution using lignite and a new cheap adsorbent (lignite washing plant tailings)

WOS: 000266660500015The present study determines the efficiency with which lignite and lignite washing plant tailings can adsorb Pb heavy metal ions. In the first experiment, the effect of size distribution on the absorbance capacity was investigated for the samples. Therefore, lignite sample was ground to five sizes (d(80) = 0.600. 0.355, 0.250, 0.106 and 0.063 mm) under nitrogen (N-2) and the tailings sample was classified into seven fractions, along with the original state (original state: d(60) = 0.063. -1 + 0.600, -0.600 + 0.355, -0.355 + 0.250, -0.250 + 0.106, -0.106 + 0.063 and -0.063 mm). The test results showed that the optimum size distributions for lignite and tailings were d(80) = 0.063 mm and the original state (d(60) = 0.063 mm), respectively. Simultaneously, the adsorption capacity results of the two optimum sizes were compared with each other, and the tailings sample (d60 = 0.063 mm) gave the best results, with 9.30 mg/g Pb ions adsorbed value. Therefore, in the second study, a series of laboratory experiments using 2(3) full factorial designs was conducted to determine the optimum pH, contact time and initial metal concentration using the original tailings sample. The experimental studies showed that pH 9, a 120 min contact time and 300 ppm initial metal concentration gave the best results, namely an adsorption of 29.92 mg Pb ions/g. (c) 2009 Elsevier Ltd. All rights reserved.Cukurova University Scientific Projects Directorate [KIMYO2006BAP1]The author thanks the Cukurova University Scientific Projects Directorate for supporting this study (Project No. KIMYO2006BAP1)

Influences of Jameson flotation operation variables on the kinetics and recovery of unburned carbon

WOS: 000264689900004The purpose of this study was to investigate the influences of Jameson flotation operation variables on the recovery and kinetics of unburned carbon (UC). The waste sample of petroleum coke, filter powder or fly ash, used in the experiments was collected from lime calcination plant tailings. The effect of Jameson flotation parameters on the recovery and kinetics efficiencies of UC was systematically studied. The feasibility of separating unburned carbon and refuse was determined from the combustible recovery (CR) and ash reduction (AR) (%) curves. Within the range studied, the optimum diesel oil dosage was 3500 g/tonne, pine oil dosage was 2500 g/tonne, pulp density was 15%, wash water rate was 0.17 cm/s and downcomer immersion depth was 50 cm. The results indicate that the Jameson flotation technique is effective in removing the UC from waste filter powder. Furthermore, the classical first-order kinetic flotation model (R=R-infinity [1 - exp (-k*t)]) was applied to data from the tests. The model was evaluated by statistical technique, after non-linear regression on the model parameters. It is found that the classical first order flotation kinetic model, most extensively used among flotation models, fits the tests data very well. (C) 2008 Elsevier B.V. All rights reserved

Effects of size distribution on flotation kinetics of Turkish sphalerite

The effects of size distribution on the flotation behaviour of sphalerite have been investigated in terms of kinetic parameters. In experimental studies, subsamples of a Turkish sphalerite ore were ground for different times using a laboratory ball mill. Timed batch tests were then undertaken using a pilot flotation column and the resulting recovery/time data were used in kinetic modelling. Results indicated that sphalerite floated rapidly at a medium particle size distribution (d80 = 0·125 mm in this case). In addition, a statistical analysis of data demonstrated that the flotation rate constant corresponded to a first-order model with rectangular distribution of floatabilities given by the equation: r = R?{1 - 1/k2t[1 - exp(- k2t]} © 2004 IoM Communications Ltd

Role of particle size on flotation kinetics of Turkish sphalerite ores

The effects of size distribution on the flotation behaviour of sphalerite have been investigated in terms of kinetic parameters. In experimental studies, sub-samples of a Turkish sphalerite ore were ground for different times using a laboratory ball mill. Timed batch tests were then undertaken using a pilot flotation column and the resulting recovery/time data were used in kinetic modelling. Results indicated that sphalerite floated rapidly at a medium particle size distribution (d80 = 0.125 mm in this case). In addition, a statistical analysis of data demonstrated that the flotation rate constant corresponded to a first-order model with rectangular distribution of floatabilities given by the equation r=R?{1-1/k2t[1-exp(-k 2t)]}

Sagittal spinal alignment and mobility and their relation to physical function in women with and without mild-to-moderate knee osteoarthritis

Recent studies suggest that patients with lower extremity osteoarthritis may have altered spinal posture. We aimed to investigate age and body mass index-adjusted sagittal spinal alignment and mobility and their relation to physical function in women over 40 years of age with and without mild-to-moderate knee osteoarthritis (KOA). Thirty-two women with unilateral mild-to-moderate KOA and thirty-two asymptomatic women were included. A skin-surface device was used to assess sagittal alignment and mobility of the thoracic, lumbar, and sacral regions and trunk inclination angle. Physical function was assessed using the Timed Up and Go test. Analysis of covariance was used to compare groups and correlation coefficients were calculated separately for two groups. Women with KOA had higher thoracic kyphosis and lumbar lordosis compared to asymptomatic women (p 0.05). In conclusion, women with KOA had altered spinal alignment. Spinal alignment and mobility were related to physical function in asymptomatic women over 40 years of age. Addressing sagittal spinal alignment in the clinical management of KOA may provide valuable data, especially for preventing possible spinal disorders. © 2022 Elsevier Lt

Applicability of statistical process control for surface modification plant and properties of coated calcite

Due to its low surface energy, easy dispersion, high homogeneity and whiteness, coated (modified) calcite has increasingly been used in many industries, particularly in the plastics. The demand for this product will most likely increase in the years to come. Surface modification of calcite with a fatty acid would lead to a great expansion of industrial applications. The color values of coated calcite products are the first quality parameter. Therefore, it is very important to monitor the variations in the color characteristics of the coated calcite products. It is well known that statistical process control (SPC) techniques have been widely used in the many industries. In the present study, the surface of micronized calcite was coated with stearic acid by a pin mill. X-R control graphics and process capability index were applied for monitoring variations in quality control based on color parameters (L*,a*and b*) for the pin mill plant. In addition, active ratio, particle size distribution, whiteness parameters, BET, FTIR, TGA-DTA and SEM were then determined on a coated calcite sample. The results show that the pin mill plant seems under control and the coating technology is very effective in modifying the surface of micronized calcite.products

Recovery of unburned carbon from lime calcination process using statistical technique

In this study, unburned carbon recovery from lime calcination plant tailings was investigated using diesel oil, kerosene, MIBC and pine oil. A series of laboratory experiments using 23 full factorial designs was conducted to determine the types and dosages of collector and frother. For these tests, data were analyzed by the paired t-test. The main and interaction effects on combustible recovery were evaluated using Yates' analysis. By optimizing the flotation parameters at slurry concentration of 34% solids, flotation time of 2.5 min, pH of 7.5, collector diesel oil dosage of 2780 g/t, and frother pine oil dosage of 2620 g/t, unburned carbon (UC) has been successfully recovered with 93.07% combustible recovery (CR) and 6030 kcal/kg calorifical value. © 2006 Elsevier B.V. All rights reserved.Firat University Scientific Research Projects Management UnitThe authors thank the Kaksan Lime Company, for their great help on laboratory support. This study was supported by the Cukurova University Scientific Research Projects Directorate (project no. MMF2004BAP8)

Recovery of silver from waste radiographic films by chemical leaching

The major sources to recover silver are photo-processing solutions, spent rinse water, scrap film and scrap printing paper. As much as 80 % of the total silver processed for black and white positives and almost 100 % of the silver processed in colour work will end up in the fixer solution. The waste radiographic films used in the experiments were taken from Cukurova University, Balcali Hospital, Adana, Turkey and cut into small pieces. The film pieces (1-9 g) were boiled with 100 mL of various quantities of oxalic acid, nitric acid and sodium hydroxide solutions for about 2.5, 5.0, 7.5 and 10 min at boiling temperature = 97 °C). The aim of the study is to recover silver from waste radiographic films by HNO3 leaching. To optimize the results of the experimental work, variance analysis was used. The statistical tests (F-tests) showed that nitric acid gave the best results compared with the other agents. Under optimum leaching conditions (radiographic films quantity, 50 g/L; nitric acid concentration, 30 g/L; stirring speed, 180 rpm; leaching time, 15 min) 89 % silver recovery was obtained

Applicability of statistical process control for surface modification plant and properties of coated calcite

Due to its low surface energy, easy dispersion, high homogeneity and whiteness, coated (modified) calcite has increasingly been used in many industries, particularly in the plastics. The demand for this product will most likely increase in the years to come. Surface modification of calcite with a fatty acid would lead to a great expansion of industrial applications. The color values of coated calcite products are the first quality parameter. Therefore, it is very important to monitor the variations in the color characteristics of the coated calcite products. It is well known that statistical process control (SPC) techniques have been widely used in the many industries. In the present study, the surface of micronized calcite was coated with stearic acid by a pin mill. X-R control graphics and process capability index were applied for monitoring variations in quality control based on color parameters (L*, a* and b*) for the pin mill plant. In addition, active ratio, particle size distribution, whiteness parameters, BET, FTIR, TGA-DTA and SEM were then determined on a coated calcite sample. The results show that the pin mill plant seems under control and the coating technology is very effective in modifying the surface of micronized calcite products