Interpretation of experimental data from rapid compression machines without creviced pistons

Over the last two decades, experimental data of the nature of species evolution profiles and ignition delays from rapid compression machines (RCMs) has been used to develop and validate chemical kinetic mechanisms at low-to-intermediate temperatures and elevated pressures. A significant portion of this overall dataset is from RCMs that had not employed a creviced piston to contain the roll-up vortex. The detrimental influence of the roll-up vortex and the thermokinetic interactions due to the resulting temperature non-homogeneity during the negative temperature coefficient (ntc) regime have been documented in the literature. However, the adequacy of the homogeneous modeling of RCMs without creviced pistons during reactive conditions has not been investigated. In this work, computational fluid dynamics simulations of an RCM without a creviced piston are conducted for autoignition of n-heptane over the entire ntc regime over a range compressed pressures from 5 to 18 bar. The results from the CFD simulations highlight the non-homogeneity of autoignition and reveal significant quantitative discrepancy in comparison to homogeneous modeling, particularly for the hot ignition delay in the ntc regime. Specifically, the roll-up vortex induced temperature non-homogeneity leads to diminution of the ntc behavior. The experimental data from RCMs without creviced piston needs to be taken with caution for quantitative validation and refinement of kinetic mechanism, particularly at conditions when ntc behavior is highly pronounced.     

Vulnerabilities in Chen and Deng's RFID mutual authentication and privacy protection protocol

As incorporation of RFID (Radio Frequency IDentification) tags in a wide variety of applications increase, there is a need to ensure the security and privacy of the entity to which these tags are attached. Not surprisingly, this is a very active area as attested by the large number of related published research literature. Recently, the journal engineering applications of artificial intelligence published a paper by Chen and Deng (2009) where the authors propose a mutual authentication protocol for RFID. This protocol has fundamental flaws that can be readily taken advantage by a resourceful adversary. We identify and discuss these vulnerabilities and point out the characteristics of this protocol that exposes it to these vulnerabilities.     

Autoignition and front propagation in low temperature combustion engine environments

In this paper, we computationally investigate the fundamental aspects of autoignition and subsequent combustion phenomena in low temperature combustion (LTC) engine environments using direct numerical simulations (DNS). In particular, the effects of thermal and equivalence ratio stratification on the autoignition and subsequent front propagation in high pressure and stratified hydrogen-air turbulent mixtures are studied using detailed chemistry. Depending on fuel injection timing, exhaust gas recirculation, and wall heat loss, different correlations between temperature (T) – equivalence ratio (?) fields can exist prior to the major heat release event. Here, we investigate three cases with different initial T–? correlations: (A) a baseline case of a uniform composition with temperature inhomogeneities only, (B) uncorrelated T–? fields, and (C) negatively-correlated T–? fields. Numerical diagnostics are developed based on an appropriately defined Damköhler number to distinguish different modes of heat release. It is found that the majority of heat release in the baseline case and the uncorrelated case occurs during the front propagation in the form of both spontaneous ignition fronts as well as deflagration waves, whereas the negatively correlated case ignites predominantly homogeneously.     

Inherent Thermometry in a Hybrid Superconducting Tunnel Junction

We discuss inherent thermometry in a Superconductor-Normal metal-Superconductor tunnel junction. In this configuration, the energy selectivity of single-particle tunneling can provide a significant electron cooling, depending on the bias voltage. The usual approach for measuring the electron temperature consists in using an additional pair of superconducting tunnel junctions as probes. In this paper, we discuss our experiment performed on a different design with no such thermometer. The quasi-equilibrium in the central metallic island is discussed in terms of a kinetic equation including injection and relaxation terms. We determine the electron temperature by comparing the micro-cooler experimental current-voltage characteristic with isothermal theoretical predictions. The limits of validity of this approach, due to the junctions asymmetry, the Andreev reflection or the presence of sub-gap states are discussed.     

Characterization and Studies on Hydro Dynamically Stable Operation of an Angular Jet SOG for COIL

Chemical oxygen-iodine Laser (COIL) is one of the fast emerging high power laser source for near Infrared (λ=1.315μm) laser generation. The heart of the system is the singlet oxygen generator (SOG) which is a pumping source for this laser. A Jet type SOG with a novel approach was designed and fabricated. Singlet oxygen was taken out of the SOG at an angle of 40° thus avoiding the carry over of droplets, which is one of the major drawbacks of horizontal system. The preliminary results have been reported in our earlier publication. The present paper discusses the performance of this generator for various operational conditions viz. diluent's gas nitrogen / helium, basic hydrogen peroxide composition, generator pressure and gas velocity. Further, conditions for the stable operation from generator as well as chlorine injection point of view have been identified.     

Phytol Derivatives as Drug Resistance Reversal Agents

Phytol was chemically transformed into fifteen semi‐synthetic derivatives, which were evaluated for their antibacterial and drug resistance reversal potential in combination with nalidixic acid against E. coli strains CA8000 and DH5α. The pivaloyl ( 4 ), 3,4,5‐trimethoxybenzoyl ( 9 ), 2,3‐dichlorobenzoyl ( 10 ), cinnamoyl ( 11 ), and aldehyde ( 14 ) derivatives of phytol ((2E,7R,11R)‐3,7,11,15‐tetramethyl‐2‐hexadecen‐1‐ol) were evaluated by using another antibiotic, tetracycline, against the MDREC‐KG4 clinical isolate of E. coli. Derivative 4 decreased the maximal inhibitory concentration (MIC) of the antibiotics by 16‐fold, while derivatives 9 , 10 , 11 , and 14 reduced MIC values of the antibiotics up to eightfold against the E. coli strains. Derivatives 4 , 9 , 10 , 11 , and 14 inhibited the ATP‐dependent efflux pump; this was also supported by their in silico binding affinity and down‐regulation of the efflux pump gene yojI, which encodes the multidrug ATP‐binding cassette transporter protein. This study supports the possible use of phytol derivatives in the development of cost‐effective antibacterial combinations.     

Evaluation of intratympanic formulations for inner ear delivery: methodology and sustained release formulation testing

A convenient and efficient in vitro diffusion cell method to evaluate formulations for inner ear delivery via the intratympanic route is currently not available. The existing in vitro diffusion cell systems commonly used to evaluate drug formulations do not resemble the physical dimensions of the middle ear and round window membrane. The objectives of this study were to examine a modified in vitro diffusion cell system of a small diffusion area for studying sustained release formulations in inner ear drug delivery and to identify a formulation for sustained drug delivery to the inner ear. Four formulations and a control were examined in this study using cidofovir as the model drug. Drug release from the formulations in the modified diffusion cell system was slower than that in the conventional diffusion cell system due to the decrease in the diffusion surface area of the modified diffusion cell system. The modified diffusion cell system was able to show different drug release behaviors among the formulations and allowed formulation evaluation better than the conventional diffusion cell system. Among the formulations investigated, poly(lactic-co-glycolic acid)–poly(ethylene glycol)–poly(lactic-co-glycolic acid) triblock copolymer systems provided the longest sustained drug delivery, probably due to their rigid gel structures and/or polymer-to-cidofovir interactions.     

Compositional variation in β‐carotene content,carbohydrate and antioxidant enzymes in selected banana cultivars

Banana is one of the most important tropical fruits, and India ranks first in its world production. Banana cultivars rich in provitamin A carotenoids may offer a potential food source for alleviating vitamin A deficiency, particularly in developing countries. With a view to exploit banana peels as a source of valuable components, in the present study, proximate composition, carotenoids, beta‐carotene and some anti‐oxidative enzymes as well as carbohydrate content of selected Indian banana varieties were determined. Karpooravalli cultivar of banana showed the maximum accumulation of carotenoid content in the non‐edible (68 μg g^?1 d.w.) portion of banana, while being the second highest in beta‐carotene content (143.12 μg per 100 g). However, Red Banana ranked highest in total carotenoid contents for pulp (4 μg g^?1 d.w.) and beta‐carotene was estimated to be the highest in the case of peels (241.91 μg per 100 g) and in pulp (117.2 μg per 100 g). Karpooravalli cultivar of banana is also rich in carbohydrate content in terms of total starch (1786.0 μg g^?1 d.w. in peels and 544.85 μg g^?1 d.w. in pulp) and sugars (53.53 μg g^?1 d.w. in peels and 39.05 μg g^?1 d.w. in pulp). The catalase enzyme activity in these peels ranged from 5.66 to 35.57 nmol min^?1 mg^?1 proteins and was found at a higher level in cultivar Poovan, while the ascorbate peroxidase showed the range of 2.25 to 6.22 μmol min^?1 mg^?1 proteins. The peels of cultivars Red Banana and Karpooravalli are rich source of bioactive compounds, such as carotenoids (beta‐carotene), anti‐oxidative enzymes and carbohydrate contents.     

Hand-Gesture Computing for the Hearing and Speech Impaired

An instrumented data glove with a wireless interface provides convenient and natural human-computer interaction for people with speech or hearing impairments.     

Experimental and thermal analysis of energy efficient novel design wet cooling towers

Waste heat is generally dissipated from process water to atmospheric air in cooling towers. In the present study, a novel design is used to extract more amount of heat without any additional energy input by incorporating secondary ambient air in an induced draft wet cooling tower. In addition, more fresh air is induced in the tower from the rain zone, which increases the effectiveness at any value of the water to air flow rate (L/G ratio). Moreover, tower characteristics, range, and evaporation loss were also increased due to the novel design. It is noteworthy that secondary fresh air increases effectiveness, heat rejection, and tower characteristics by 10.12%, 19.65%, and 26.11%, respectively, and decreases approach by 16.32% at 0.55 L/G ratio, 44°C inlet water temperature, 29.7°C dry bulb temperature, and 18.4°C inlet air wet bulb temperature.