Influence of the Nature of A Cation on Dynamics of Charge Transfer Processes in Perovskite Solar Cells

The electronic processes occurring within the perovskite solar cells (PSCs) are strongly influenced by the nature of the organic A cations present within the inorganic framework. In this study, the impact of FA (CH(NH₂)₂⁺) and Cs⁺ cations on the intrinsic and interfacial properties in the FAPbBr₃ and CsPbBr₃ PSCs is investigated. The analysis of current density ( J _SC) and photovoltage ( V _OC) as a function of illumination intensity establishes that the interfacial charge transport is more rapid in FAPbBr₃ devices. Small perturbation measurements including intensity modulated photocurrent and photovoltage spectroscopy are applied to explore the resistive and capacitive elements. Furthermore, electrochemical impedance spectroscopy measurements are found to correlate well with the photovoltaic characteristics of FAPbBr₃ and CsPbBr₃ PSCs. Overall, the in‐depth analysis of various phenomena occurring within the bromide PSCs allows to underline the working principle, which provides a key to optimize the device performance. The present protocol is not only valid for PSCs but can also be extended to devices based on alternative light harvesters.     

Design and experimental evaluation of OnDemand inter-domain mobility in SDN supported PMIPv6

Wireless Networks - The soaring number of mobile devices and their demands for enhanced services have forced operators to adopt locally software defined and globally distributed multi-domain...     

Spatial context-based optimal multilevel energy curve thresholding for image segmentation using soft computing techniques

Neural Computing and Applications - Image segmentation using multilevel thresholding (MT) is one of the leading methods. Although, as most techniques are based on the image histogram to be...     

Performance Enhancement of 5G OFDM Systems Using Modified Raised Cosine Power Pulse

Wireless Personal Communications - OFDM is a key modulation technology of current wireless communication systems such as 4G LTE/LTE-A. The fifth generation (5G) of wireless cellular networks is...     

A conceptual framework for the adoption of big data analytics by e-commerce startups: a case-based approach

Information Systems and e-Business Management - E-commerce start-ups have ventured into emerging economies and are growing at a significantly faster pace. Big data has acted like a catalyst in...     

Improving known solutions is hard

In this paper, we study the complexity of computing better solutions to optimization problems given other solutions. We use a model of computation suitable for this purpose, the counterexample computation model. We first prove that, if PH _P ³ , polynomial time transducers cannot compute optimal solutions for many problems, even givenn ^1– non-trivial solutions, for any >0. These results are then used to establish sharp lower bounds for several problems in the counterexample model. We extend the model by defining probabilistic counterexample computations and show that our results hold even in the presence of randomness.     

A direct variational method for planning monotonically optimal paths for redundant manipulators in constrained workspaces

This paper proposes a path planner for serial manipulators with a large number of degrees of freedom, working in cluttered workspaces. Based on the variational principles, this approach involves formulating the path planning problem as constrained minimization of a functional representing the total joint movement over the complete path. We use modified boundary conditions at both ends of the trajectory to find more suitable start and end configurations. The concept of monotonic optimality is introduced in order to optimize the manipulator paths between the resulting end configurations. For obstacle avoidance, volume and proximity based penalizing schemes are developed and used. The presented planner uses a global approach to search for feasible paths and at the same time involves no pre-processing task. A variety of test cases have been presented to establish the efficacy of the presented scheme in providing good quality paths. The extent of advantage accruing out of the measures of free end-configurations and monotonic optimality are also analyzed quantitatively.     

Evaluation of the rheological and electrical percolation of high-density polyethylene/carbon black composites using mathematical models

In this work, conductive polymer composites (CPCs) of bio-based polyethylene (BioPe) containing different concentrations of carbon black (CB) were developed. By using oscillatory rheology analysis, a Newtonian plateau was observed in BioPe, and all BioPe/CB composites had a behavior of a pseudo-solid and that composites with volume fractions ranging from 0.24 to 0.56 presented higher viscosity, storage, and loss modulus. This suggests the formation of a percolated network and by using the power-law models, it was observed that the electrical percolation threshold was higher than the rheological percolation threshold. The electrical conductivity was measured using the four-point probe method and a sigmoid model was used to predict the CPCs' electrical conductivity percolation threshold. The results indicated that the four-point probe method presented satisfactory results according to the calculated standard deviations and voltage–current characteristics for each round of measurements considering the same ranging as used in rheology analysis. The analytical model used showed a coefficient of determination (R²) higher than 95%, allowing the prediction of the electrical conductivity of the CPC and the percolation threshold as a function of the volumetric fraction of the CB.     

Spray-Dried Buccal Mucoadhesive Microparticles of Venlafaxine Based on Cress Seed Mucilage: In Vitro,in Vivo Evaluation in Rabbits

Lepidium sativum Linn. (Cruciferea) is known as garden cress or cress. Venlafaxine is prescribed in schizophrenia and anxiety. It shows a tendency of hepatic first-pass metabolism, which affects its bioavailability. The objective of this study is the extraction of cress seed mucilage and development of buccal mucoadhesive microparticles of venlafaxine based on the mucilage using a spray-drying technique. The optimized formulation was evaluated in vitro and the bioavailability of the same formulation in rabbits was assessed. Cress seed mucilage was extracted and used to prepare microparticles with varying concentrations in formulations F1–F5 (1–5% w/w) using a spray-drying technique. The microparticles were evaluated for yield, particle size, incorporation efficiency, swelling property, in vitro mucoadhesion, and in vitro drug release. Microparticles were characterized by differential scanning colorimetry, scanning electron microscopy, and X-ray diffraction studies. In vivo evaluation was carried out in rabbits. Formulation F5 showed maximum mucoadhesion (88.38 ± 1.46%), greater incorporation efficiency (89.42 ± 2.52%), and the highest swelling index (0.93 ± 0.01) compared to the other formulations. F5 showed a marked increase in bioavailability after buccal administration (52.55%) compared to an oral route (39.40%). Time to reach C _max of 23.49 ± 0.33 ng/mL was 120 min for buccal microparticles in comparison to oral solution, which took 180 min to reach C _max of 17.98 ± 1.14 ng/mL. Cress seed mucilage is suitable for production of the mucoadhesive microparticles using a spray-drying method because significant improvement in bioavailability by buccal mucoadhesive microparticles was observed.