Improved approximations for two-stage min-cut and shortest path problems under uncertainty

Mathematical Programming - In this paper, we study the robust and stochastic versions of the two-stage min-cut and shortest path problems introduced in Dhamdhere et al. (in How to pay, come what...     

Flexible, all-organic chemiresistor for detecting chemically aggressive vapors

Chemiresistors made of thin films of single-walled carbon nanotube (CNT) bundles on cellulosics (paper and cloth) can detect aggressive oxidizing vapors such as nitrogen dioxide and chlorine at 250 and 500 ppb, respectively, at room temperature in ambient air without the aid of a vapor concentrator. Inkjet-printed films of CNTs on 100% acid-free paper are significantly more robust than dip-coated films on plastic substrates. Performance attributes include low sensor-to-sensor variation, spontaneous signal recovery, negligible baseline drift, and the ability to bend the sensors to a crease without loss of sensor performance.     

Overtone bands in aniline and its chloro-derivatives--a low concentration study

Overtone spectra of aniline and its o-and m- chloro-derivatives mixed with carbon tetrachloride have been studied at different dilutions. Vibrational frequency and anharmonicity constants for the C-H stretch vibration and for the symmetric and asymmetric N-H stretch vibrations have been determined. The presence of intermolecular hydrogen bonding has been noted in all the three molecules. Intramolecular hydrogen bonding involving N-H...Cl has also been detected in o-chloroaniline.     

FeCl3-Catalyzed Pechmann Synthesis of Coumarins in Ionic Liquids

The synthesis of coumarin derivatives via Pechmann reaction using anhydrous FeCl₃ as Lewis acid catalyst in ionic liquid medium has been carried out. The best results were obtained (yields as high as 89%) with ionic liquids having bis(triflic)imide as a counteranion. The ionic liquid could easily be recovered and reused.     

Automated grain mapping using wide angle convergent beam electron diffraction in transmission electron microscope for nanomaterials

The grain size statistics, commonly derived from the grain map of a material sample, are important microstructure characteristics that greatly influence its properties. The grain map for nanomaterials is usually obtained manually by visual inspection of the transmission electron microscope (TEM) micrographs because automated methods do not perform satisfactorily. While the visual inspection method provides reliable results, it is a labor intensive process and is often prone to human errors. In this article, an automated grain mapping method is developed using TEM diffraction patterns. The presented method uses wide angle convergent beam diffraction in the TEM. The automated technique was applied on a platinum thin film sample to obtain the grain map and subsequently derive grain size statistics from it. The grain size statistics obtained with the automated method were found in good agreement with the visual inspection method.     

Optical thermometry using FIR of two close lying levels of different ions in Y2O3:Ho3+–Tm3+–Yb3+ phosphor

The possibility of combustion synthesized Ho³⁺–Tm³⁺–Yb³⁺ codoped Y₂O₃ phosphor as temperature sensor using fluorescence intensity ratio (FIR) technique under a 980 nm excitation has been reported. The variation in FIR of blue upconversion emissions generated from two closely spaced levels of the Tm³⁺ and Ho³⁺ ions (¹G₄ and ⁵F₃) as a function of temperature has been monitored up to 703 K. The maximum relative sensitivity has been found to be 3.38 × 10^?3 K^?1 which indicates that the present phosphor material can play a vital role for high optical thermometric purpose. The results imply that the FIR of two closely spaced levels of two different rare earth ions can also be used as temperature sensor.     

Synthesis,characterization and evaluation of amphoteric galactomannan derivative for the mitigation of malachite green and congo red dye from aqueous solution

Cellulose - Biopolymeric materials have been utilized for water treatment since ancient times. Consequently, novel sustainable, inexpensive and natural biobased alternatives have been explored...     

Compressive properties of magnetorheological elastomer with different magnetic fields and types of filler

Magnetorheological elastomer (MRE) specimens were prepared to find the optimum compressive characteristics using different types and amounts of iron powder. A magnetic field of up to 2 T was applied during vulcanization. Among the four types of iron powders, the specimen with round‐shaped carbonyl iron powder and small grain size shows higher magnetic effects than that with bigger and irregularly shaped electrolyte iron powder. However, the compressive modulus of the rubber with electrolyte iron powder is higher without magnetic treatment at a given amount. In general, the bigger and irregularly shaped iron particles tend to move slowly and produce nonuniform distribution when a magnetic field is applied. The experimental results show that the mechanical properties are better when applying a magnetic field of 1.5 T compared with 2.0 T during the specimen vulcanization. Applying a magnetic field of 300 mT during the compression test enhanced the compressive modulus by 12% to 15%. The rate of increase of the modulus decreased exponentially with prestrain.     

Overtone spectra of aniline derivatives

Overtone spectra of 2-ethylaniline, N-methylaniline, N-ethylaniline, N,N-dimethylaniline and N,N-diethylaniline have been studied in 2500-15000 cm(-1) region. Vibrational frequency and anharmonicity constants for aryl/alkyl C-H stretch and N-H stretch vibrations have been determined. The effect of substitution of C(2)H(5) group on the ortho position in the ring and CH(3)/C(2)H(5) at the positions of the H-atom in NH(2) group has been studied in these molecules. It is noted that the aryl C-H stretching frequency and the N-H stretching frequency is appreciably increased due to the replacement of H in NH(2) group by CH(3)/C(2)H(5). These experimental observations are well supported by theoretical calculations for charge density on N-atom using molecular orbital AM(1) method.     

Production,Purification and Characterisation of a Potential Fibrinolytic Protease from Endophytic <Emphasis Type="Italic">Xylaria curta</Emphasis> by Solid Substrate Fermentation

The present investigation highlights the optimal conditions for production of a non-toxic, bi-functional fibrinolytic enzyme xylarinase produced by endophytic fungus Xylaria curta by solid substrate fermentation using rice chaff medium. The purified enzyme is a monomeric protein with a molecular mass of ～33 kDa. The enzyme exhibits cleavage of Aα and Bβ chains of fibrin(ogen) and has no effect on γ chain. The optimal fibrinolytic activity of the enzyme was observed at 35 °C and pH 8. The fibrinolytic activity was enhanced in the presence of Ca²⁺, whereas it was completely inhibited in the presence of Fe²⁺ and Zn²⁺ ions and inhibitors like EDTA and EGTA suggesting it to be a metalloprotease. The K _m and V _max of the enzyme for azocasein were 326 μM and 0.13 μM min^?1. The N-terminal sequence of the enzyme (SNGPLPGGVVWAG) was same when compared to xylarinase isolated from culture broth of X. curta. Thus, xylarinase could be exploited as a potent clot busting enzyme which could be produced on large scale using solid substrate fermentation.