Performance investigation of heat pipe using aqueous solution of n-Pentanol with different inclinations

The orientation of the heat pipe plays the significant role in its performance. In specific orientations, the performance of the heat pipe is directly related to the wick structure. In conventional heat pipe, the working fluid is used a negative surface-tension gradient with temperature. It is an unfavorable one and it decreases the heat transport between the evaporator section and the condenser section. An Aqueous solution of n-Pentanol having a positive surface tension gradient with temperature is suggested as a working medium for heat pipe to improve the performance of capillary limit and operating stability. The objective of this paper is to perform a comparative study of heat pipe performance using the aqueous solution of n-Pentanol with water at various inclinations. The results are presented to demonstrate the merits and suitability of the aqueous solution of n-Pentanol as a working fluid for heat pipe.     

Effect of graphene oxide on the interlaminar fracture toughness of carbon fiber/epoxy composites

Graphene oxide (GO) nanoparticles were introduced in the interlaminar region of carbon fiber–epoxy composites by dispersing it in a thermoplastic polymer carrier such as polyvinylpyrrolidone (PVP). Mode‐I fracture toughness (G_IC) was investigated using double cantilever beam testing to evaluate the effect of the GO on the delamination behavior of the composite. The GO content was varied from 0% to 7% by weight as a function of the PVP content. Improvement of ～100% in the Mode I fracture toughness (G_IC) was observed compared to composites with no GO. The optimum amount of nanoparticles for improving the interlaminar fracture toughness was found to be ～0.007% by weight of the composite. The increase in the value of flexural strength value was also observed. Scanning electron microscopy of fracture surfaces, X‐ray diffraction, and transmission electron microscopy, and reflectance Fourier transform infrared spectra, as well as Raman spectroscopy results, are presented to support the conclusions. POLYM. ENG. SCI., 59:1199–1208 2019. © 2019 Society of Plastics Engineers     

Validating female psychopathy subtypes: Differences in personality, antisocial and violent behavior, substance abuse, trauma, and mental health.

Recent empirical investigations utilizing male prisoners have begun to validate clinical conceptualizations of primary and secondary psychopathy subtypes. We extended this literature by identifying similar psychopathic subtypes in female prisoners on the basis of personality structure using model-based cluster analysis. Secondary psychopaths (n = 39) were characterized by personality traits of negative emotionality and low behavioral constraint, an early onset of antisocial and criminal behavior, greater substance use and abuse, more violent behavior and institutional misconduct, and more mental health problems, including symptoms of posttraumatic stress disorder and suicide attempts. Primary psychopaths (n = 31) exhibited few distinguishing personality features but were prolific criminals especially in regards to nonviolent crime, and exhibited relatively few mental health problems despite substantial exposure to traumatic events. The results support alternative etiological pathways to antisocial and criminal behavior that are evident in personality structure as well as gender similarities and differences in the manifestation of psychopathic personalities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extrapolated fmax of heterojunction bipolar transistors

It is shown that the extrapolated f_max of heterojunction bipolar transistors (HBT's) can be written in the form f _max=√f_T/8π(RC)_eff, where f_T is the common-emitter, unity-current-gain frequency, and where (RC)_eff is a general time constant that includes not only the effects of the base resistance and collector-base junction capacitance, but also the effects of the parasitic emitter and collector resistances, and the dynamic resistance 1/g_m, where g_m is the transconductance. Simple expressions are derived for (RC) _eff, and these are applied to two state-of-the-art devices recently reported in the literature. It is demonstrated that, in modern HBT's, (RC)_eff can differ significantly from the effective base-resistance-collector-capacitance product conventionally assumed to determine f_max     

Mechanism of spallation in platinum aluminide/electron beam physical vapor-deposited thermal barrier coatings

The spallation failure of a commercial thermal barrier coating (TBC), consisting of a single-crystal RENE N5 superalloy, a platinum aluminide (Pt-Al) bond coat, and an electron beam-deposited 7 wt pct yttria-stabilized zirconia ceramic layer (7YSZ), was studied following cyclic furnace testing. In the uncycled state and prior to deposition of the ceramic, the Pt-Al bond-coat surface contains a cellular network of ridges corresponding to the underlying bond-coat grain-boundary structure. With thermal cycling, the ridges and associated grain boundaries are the sites of preferential oxidation and cracking, which results in the formation of cavities that are partially filled with oxide. Using a fluorescent penetrant dye in conjunction with a direct-pull test, it is shown that, when specimens are cycled to about 80 pct of life, these grain-boundary regions show extensive debonding. The roles of oxidation and cyclic stress in localized grain boundary region spallation are discussed. The additional factors leading to large-scale TBC spallation are described.     

Look-up table (LUT) method for inverse halftoning

In this paper we propose look-up table (LUT) based methods for inverse halftoning of images. The LUT for inverse halftoning is obtained from the histogram gathered from a few sample halftone images and corresponding original images. The method is extremely fast (no filtering is required) and the PSNR and visual image quality achieved is comparable to the best methods known for inverse halftoning. The LUT inverse halftoning method does not depend on the specific properties of the halftoning method, and can be applied to any halftoning method. Then, an algorithm for template selection for LUT inverse halftoning is introduced. We demonstrate the performance of the LUT inverse halftoning algorithm on error diffused images and ordered dithered images. We also extend LUT inverse halftoning to color halftones.     

Optimization of fermentation parameters for enhanced production of naringinase by soil isolate Aspergillus niger VB07

Aspergillus niger VB07 was isolated from the soil of citrus fruit market used to produce extracellular naringinase in a liquid medium. Various parameters of fermentation have been examined in order to improve overall enzyme yield. Naringinase yield of 17.28 IU/mL in an optimized medium containing naringin (0.1%), rhamnose (0.5%), peptone (0.25%), glycine (10 mM), and pH 4.5 at 28°C for 7 days has been obtained at shake flask level. Compared to the initial medium, the highest naringinase yield observed is approximately increased by 1.8 times under the optimized conditions. Amino acids mediated naringinase synthesis was reported.     

Vector competence of mosquitoes (Diptera:Culicidae) from Massachusetts for a sympatric isolate of eastern equine encephalomyelitis virus

This study examined the characteristics of students with specific learning disabilities in either reading and spelling or arithmetic. Based on scores obtained using the revised Woodcock-Johnson Psycho-Educational Battery, students with a marked weakness in arithmetic relative to reading and spelling were designated as Group A. Group R-S showed the opposite pattern. Each group included 30 participants ranging in age from 7 to 16 years, with a mean age of 10 years. The boy-to-girl ratios were 16:14 and 19:11 in Group A and Group R-S, respectively. Comparisons using measures from the Wechsler Intelligence Scale for Children-Third Edition (WISC-III) indicated that Group A was weaker in nonverbal skills than Group R-S, despite equivalent overall IQ scores between the two groups. Group R-S showed a within-group strength in nonverbal versus verbal skills. Group A students were more likely than Group R-S students to have counseling provided as part of their Individualized Education Program, suggesting greater socioemotional difficulty among Group A students. The present study supports the connection between nonverbal skills and socioemotional functioning noted by previous researchers, and generalizes findings from earlier studies to more current test editions.     

A novel memristive neural network with hidden attractors and its circuitry implementation

Neural networks have been applied in various fields from signal processing, pattern recognition, associative memory to artificial intelligence. Recently, nanoscale memristor has renewed interest in experimental realization of neural network. A neural network with a memristive synaptic weight is studied in this work. Dynamical properties of the proposed neural network are investigated through phase portraits, Poincaré map, and Lyapunov exponents. Interestingly, the memristive neural network can generate hyperchaotic attractors without the presence of equilibrium points. Moreover, circuital implementation of such memristive neural network is presented to show its feasibility.