Single and dual gate OTFT based robust organic digital design

This paper analyzes and compares the performance of the single gate (SG) and dual gate (DG) organic thin film transistors (OTFTs) based inverter circuits. The DG-OTFT device performs better than SG-OTFT mainly in terms of mobility, on–off current ratio and sub-threshold slope. The mobility of DG device is almost five times higher than the SG, while, an increase of 74% in on–off current ratio and a decrease of 41% in sub-threshold slope are observed. Two different configurations of inverter circuits i.e. diode-load logic (DLL) and zero-V_gs-load logic (ZVLL) are studied. The static and dynamic behaviors of the p-type DLL and ZVLL inverters using SG and DG organic transistors are observed. The DG-OTFT improves gain and noise margins for both DLL and ZVLL inverter circuits. Using DG device, propagation delay reduces by 59% for DLL and 42% for ZVLL as compared to SG OTFT based configurations. Moreover, fixed back gate bias technique further enhances the noise margin and gain by 8% and 18% for DLL and 19% and 26% for ZVLL configurations, respectively. Finally, bootstrapping technique is also applied to the dual gate inverters that further boosts the noise margin and gain for DLL and ZVLL configurations.     

Synthesis,properties and thermal stability of water‐soluble poly(potassium 1‐hydroxyacrylate‐co‐styrene) copolymer

The present work investigates the structure properties of copolymers using thermogravimetric analysis, hot stage microscopy, static light scattering, field emission scanning electron microscopy, X‐ray diffraction analysis and a Brookfield viscometer. Poly(potassium 1‐hydroxyacrylate) (PKHA) is a water‐soluble polymer. However, the copolymer of styrene and 2‐isopropyl‐5‐methylene‐1,3‐dioxolan‐4‐one is not water soluble at equal molar ratio because the polystyrene reduces the solubility. The effect of styrene on poly(potassium 1‐hydroxyacrylate‐co‐styrene) copolymer, i.e. poly(KHA‐co‐St), was investigated for the increasing solubility of the copolymer. The solubility was increased at a lower molar ratio of styrene such as 0.4 in the copolymer. It was found that the copolymer was soluble in water when a content ratio of 68/32 mol% of homopolymer was incorporated in poly(KHA₆₈‐co‐St₃₂) copolymer as determined by NMR analysis. Also the poly(KHA₆₈‐co‐St₃₂) copolymer was found to be salt tolerant, possessed water absorption capacity and was thermally stable up to 183 °C. Moreover, it is shown that the polystyrene content plays a key role in the thermal stability of the copolymer. © 2017 Society of Chemical Industry     

Optimization of the Electrical Performance of Polymeric Films

In the present study, an attempt is made to optimize the electrical performance of the thin polymeric films through optimization techniques. The study is conducted in two phases: (1) laboratory experiments and (2) through numerical optimization. For laboratory analysis, thin and transparent films are prepared using polyethersulfone (PES) as host material and meta-nitroaniline (MNA) as guest materials. A set of nine film samples are prepared by the solution casting method in the laboratory using different concentrations of MNA. The electrical properties capacitance, conductance, and dissipation factor of films are measured by Aligent Impedance Analyzer. These characteristics are then optimized mathematically. For this purpose, initially single-objectives are considered for optimizing the electrical properties individually, and later a multiobjective model is considered for analyzing the properties simultaneously. The algorithms employed are metaheuristics: genetic algorithms, particle swarm optimization, differential evolution, and its variant modified differential evolution along with fmincon (a MATLAB toolbox) for single-objective optimization and multiobjective differential evolution algorithm and nondominated sorting genetic algorithm-II for multiobjective optimization.     

Nanosized PbZrO3 Powder from Oxalate Precursor: Microwave-Aided Synthesis and Thermal Characterization

Nanosized lead zirconate (PbZrO₃) powder was synthesized from its oxalate precursor, namely lead zirconyl oxalate (LZO). LZO heated in a microwave heating system for 1 h yielded the PbZrO₃ at 600°C. The same precursor (LZO), when heated in a resistance-heated furnace at 850°C for 3 h, does not give a pure product. Thermogravimetry, differential thermal analysis, and X-ray diffraction techniques were used to characterize the precursor and optimize the conditions for microwave processing. The particle size of PbZrO₃ powder prepared at 600°C using microwave heating was measured using transmission electron microscopy (TEM). The TEM images show that the particles of PbZrO₃ are spherical in shape and that the particle size varies between 20 and 22 nm.     

An ant colony algorithm for scheduling in flowshops with sequence-dependent setup times of jobs

The problem of scheduling in flowshops with sequence-dependent setup times of jobs is considered and solved by making use of ant colony optimization (ACO) algorithms. ACO is an algorithmic approach, inspired by the foraging behavior of real ants, that can be applied to the solution of combinatorial optimization problems. A new ant colony algorithm has been developed in this paper to solve the flowshop scheduling problem with the consideration of sequence-dependent setup times of jobs. The objective is to minimize the makespan. Artificial ants are used to construct solutions for flowshop scheduling problems, and the solutions are subsequently improved by a local search procedure. An existing ant colony algorithm and the proposed ant colony algorithm were compared with two existing heuristics. It was found after extensive computational investigation that the proposed ant colony algorithm gives promising and better results, as compared to those solutions given by the existing ant colony algorithm and the existing heuristics, for the flowshop scheduling problem under study.     

Towards functional labeling of utility vehicle point clouds for humanoid driving

We present work on analyzing 3-D point clouds of a small utility vehicle for purposes of humanoid robot driving. The scope of this work is limited to a subset of ingress-related tasks including stepping up into the vehicle and grasping the steering wheel. First, we describe how partial point clouds are acquired from different perspectives using sensors, including a stereo camera and a tilting laser range finder. For finer detail and a larger model than one sensor view alone can capture, a Kinect Fusion (Izadi et al. in KinectFusion: realtime 3D reconstruction and interaction using a moving depth camera, 2011)-like algorithm is used to integrate the stereo point clouds as the sensor head is moved around the vehicle. Second, we discuss how individual sensor views can be registered to the overall vehicle model to provide context, and present methods to estimate both statically and dynamically several geometric parameters critical to motion planning: (1) the floor height and boundaries defined by the seat and the dashboard, and (2) the steering wheel pose and dimensions. Results are compared using the different sensors, and the usefulness of the estimated quantities for motion planning is also addressed.     

Structure–property relationship in copolyesters. I. Preparation and characterization of ethylene terephthalate–hexamethylene terephthalate copolymers

Poly(ethylene terephthalate)-containing ethylene and hexamethylene residues in the polymer backbone were prepared by melt condensation reaction of dimethyl terephthalate (DMT) and diffrent quantities of ethylene glycol (EG) and 1,6-hexane diol (H) in the initial monomer feed. Several polyester samples were prepared by varying the mol % of 1,6-hexane diol with respect to ethylene glycol in the initial monomer feed. These included 0.0 (PET), 2.5 (H₁), 5.0 (H₂), 7.5 (H₃), 10.0 (H₄), 12.5 (H₅), 15.0 (H₆), 17.5 (H₇), 20.0 (H₈), 50.0 (H₉), 80.0 (H₁₀), and 100.0 (H₁₁), respectively. The polymers were characterized by recording IR spectra and intrinsic viscosity measurements. The relative thermal stability of the polymers was evaluated by dynamic thermogravimetry in air. An increase in mol % of 1,6-hexane diol resulted in a decrease in melting points and thermal stability of copolymers. PET and copolyesters were spun to fibers by using the melt-spinning technique. The fibers were drawn to draw ratios 2,3,4, and 5. In case of copolymes, tensile strength decreases slightly with increasing mol % of H whereas % elongation increases. The moisture regain and dye uptake in copolyesters was treatly enhanced as compared to PET.     

Enhancement of <Emphasis Type="Italic">Chlorella vulgaris</Emphasis> cell density: Shake flask and bench-top photobioreactor studies to identify and control limiting factors

Low cell density is a major bottleneck in any microalgal bioprocess that prevents the large scale exploitation of this potential bioresource from commercialization of commodities like biofuels. Control of factors limiting growth is the key to enhancing cell density. Factors limiting photoautotrophic growth of C. vulgaris were identified and controlled to a possible extent. Limiting CO₂-transfer rate, light attenuation, scarcity of nutrients, and high pH compounded to retard growth gradually in the basal medium. Analysis of the maximum feasible CO₂ mass-transfer rate and CO₂ fixation rates enabled the assessment of CO₂-limited growth without on-line estimation of dissolved CO₂. Growth (1.4×10⁸ cells mL^?1, 12.6 g dry wt L^?1) was extensively enhanced when limiting factors were staved in a customized 250mL stirred-tank photobioreactor. Scaling the culture 8 times with constant k _L a (volumetric mass-transfer coefficient) and Re _i (impeller Reynolds number) resulted in reduction of biomass titer by 80% because of light attenuation.