Photocatalytic production of hydrogen from electrodeposited film and sacrificial electron donors

A new approach to combining a p-type semiconductor photocathode with sacrificial electron donors in the anode compartment in a two-compartment cell is described for photocatalytic hydrogen production. This approach is demonstrated for electrodeposited p-Cu₂O film supported on a transparent conducting oxide substrate. The oxide semiconductor surface was photochemically modified in situ with an ultra-thin Ni layer prior to use. A variety of organic and organometallic electron donors was screened by cyclic voltammetry, and the optimal candidate was hydroquinone at pH 10. Importantly, no photocurrents were measured at zero bias voltage in the two-compartment cell in the absence of an electron donor, signaling that water photosplitting is not feasible with p-Cu₂O. Methyl viologen (MV²⁺) was effective as an electron relay in the photocathode chamber as shown by in situ spectroscopic monitoring of the MV⁺ radical cations. Finally, practical perspectives of this new approach and value-added options for combining it with pollutant destruction are described.     

Emissivity of substrate supported films

Results of experimental measurements of emissivity carried out on cobalt oxide and nickel sulphide films deposited on aluminum substrates are reported in this paper. Experimental results supported the general behaviour of variation of emissivity with film thickness as reported theoretically. The theoretical model is based on the interaction and attenuation of the emitted wavelengths from the substrate and film materials.     

Modelling of mode-I stable crack growth under hydrogen assisted stress corrosion cracking

The paper presents a new strategy based on combined analytical and finite element (FE) solution to hydrogen assisted stress corrosion crack growth. The diffusion process is solved analytically through both one-and two-dimensional modelling. These solutions are adopted with two-dimensional FE based cohesive zone model of crack extension study. The results fit well with published experimental data and show improvement over the predictions by full FE approach. The new solution approach helps to reduce time required for simulation/computation. The study has produced a relationship between concentration dependent reduction in cohesive strength and plastic strain rate.     

Analgesic Effect of Tranilast in an Animal Model of Neuropathic Pain and Its Role in the Regulation of Tetrahydrobiopterin Synthesis

Trigeminal neuralgia is unilateral, lancinating, episodic pain that can be provoked by routine activities. Anticonvulsants, such as carbamazepine, are the drugs of choice; however, these possess side-effects. Microvascular decompression is the most effective surgical technique with a higher success rate, although occasionally causes adverse effects. The potential treatment for this type of pain remains unmet. Increased tetrahydrobiopterin (BH4) levels have been reported in association with axonal injury. This study aimed to evaluate the effect of tranilast on relieving neuropathic pain in animal models and analyze the changes in BH4 synthesis. Neuropathic pain was induced via infraorbital nerve constriction. Tranilast, carbamazepine, or saline was injected intraperitoneally to assess the rat’s post-intervention pain response. In the von Frey’s test, the tranilast and carbamazepine groups showed significant changes in the head withdrawal threshold in the ipsilateral whisker pad area. The motor coordination test showed no changes in the tranilast group, whereas the carbamazepine group showed decreased performance, indicating impaired motor coordination. Trigeminal ganglion tissues were used for the PCR array analysis of genes that regulate the BH4 pathway. Downregulation of the sepiapterin reductase (Spr) and aldoketo reductase (Akr) genes after tranilast injection was observed compared to the pain model. These findings suggest that tranilast effectively treats neuropathic pain.     

Performance Tuning and Reliability Analysis of the Electrostatically Configured Nanotube Tunnel FET with Impact of Interface Trap Charges

Silicon - This paper examines, an electrostatically configured Nano-Tube Tunnel Field-Effect Transistor (ED-NTTFET). During the fabrication process, different charges such as fixed charge, oxide...     

Computer Aided Tolerance assignment

Tolerances are basic to the production of every part. This is because perfect parts cannot be produced with existing processes and machines. The determination of tolerances for the individual parts of a functional assembly is critical, but not trivial. Numerous approaches are suggested in past literature for (analytical) tolerance allocation. With the advent of total automation, more attempts are being made to computerize manual design tasks. Tolerance design, assignment and allocation can also be fully automated if the assembly function can be estimated by the computer.

In the present paper, an attempt is made to computerize tolerance assignment. A simple example of a two piece assembly, viz., a fit, is used to demonstrate the developed methodology. A feature extraction is first performed from both detail and assembly drawings. Then, probable assembly interfaces are determined using a rule based procedure. Consequently, tolerances are assigned to the basic dimensions of each feature and to the assembly interfaces using a tolerance database and user interaction. More complex analysis for tolerance allocation is also under study.     

The Katapayadi formula and the modern hashing technique

The essence of the modern hashing technique in computer science is the derivation of a number from a nonnumeric key to index into a table where the record containing the key is stored. In this paper, an interestingly similar technique used in South Indian musicology in the 18th century is described, and the question of whether it is an anticipation of the hashing technique is briefly addressed. The problem of retrieving a record from a table based upon a given key has been studied extensively. In this paper, I describe one particular approach to this problem-hashing-and also an interesting earlier development very similar to it. It is generally believed that the idea of hashing was originated by H.P. Luhn (1953), and first described in the open literature by A.I. Dumey (1956), but is it possible that the Katapayadi scheme of deriving numbers from names-in conjunction with the applications to which it had been put, especially in classical South Indian musicology-is an early anticipation of the hashing technique? I discuss this issue in detail in this paper     

Performance-driven MCM partitioning through an adaptive geneticalgorithm

We present a novel genetic algorithm-based partitioning scheme for multichip modules (MCM's) which integrates four performance constraints simultaneously: pin count, area, heat dissipation, and timing. We also present a similar partitioning algorithm based on evolutionary programming. Experimental studies demonstrate the superiority of these methods over deterministic Fiduccia-Mattheyes (FM) algorithm and simulated annealing (SA) technique. Our approach performs better than another genetic algorithm-based method recently reported. The adaptive change of crossover and mutation probabilities results in better convergence of the partitioning algorithm     

Z-dol Versus Z-tetraol: Bonding and Durability in Magnetic Hard Disk Application

A component-level study has revealed that the durability of magnetic hard disks coated with Z-dol improved with increasing level of relative humidity, while the durability of disks coated with Z-tetraol was generally superior and not affected by the humidity within the range investigated (8–80%). It has been shown earlier that water molecules effectively passivate the catalytic centers responsible for the lubricant degradation. The Z-dol molecular chain has a hydroxyl group at each end, while the Z-tetraol molecular chain has two hydroxyl groups at each end. Having surmised that the superior performance of Z-tetraol can be ascribed to its ability to retain water molecules at its multiply hydroxylated ends, the solubility of water in Z-dol, Z-tetraol, and Z-TX were investigated using proton NMR spectroscopy. The study revealed that Z-tetraol is not only able to retain a much larger number of water molecules at its ends, but also is able to form stronger hydrogen bonds. Z-tetraol would then bond more tightly to the carbon overcoat (via hydrogen bonding with the surface hydroxyl groups), and be more resistant against catalytic degradation owing to its affinity to, and retention of water molecules.