Applied Science Private University

About: Applied Science Private University is a education organization based out in Amman, Jordan. It is known for research contribution in the topics: Population & Catalysis. The organization has 4124 authors who have published 5299 publications receiving 116167 citations.

Production, characterization and reactivity studies of chars produced by the isothermal pyrolysis of flax straw

Abstract: The influence of pyrolysis temperature and residence time on the char yields and resultant char characteristics were investigated in the isothermal pyrolysis of flax straw. The pyrolysis temperature was varied in the range between 300 and 500 °C and reaction residence time was varied from 15 to 60 min. The char yield was found to decrease with both increasing pyrolysis temperature and residence time. The char structure and physical characteristics were thoroughly investigated by means of X-ray diffraction (XRD), temperature-programmed oxidation (TPO) and N 2 physisorption techniques. The results show that the degree of porosity and graphitization increased with increasing pyrolysis temperature and time. TPO studies on the char samples corroborate well with the XRD findings and showed the presence of two types of carbon; namely, amorphous filamentous carbon and crystalline graphitic carbon. Thermogravimetric analysis (TGA) of the char was performed to understand the combustion kinetics and reactivity. Chars formed at lower pyrolysis temperatures were found to be more reactive than the chars produced at higher pyrolysis temperatures, and these findings are well supported by the TPO, TGA, N 2 physisorption and XRD characterization data. Furthermore, an empirical global kinetic model was devised based on power law and used to estimate the activation energy and other kinetic parameters of both flax straw pyrolysis and char combustion processes.

Robust general N user authentication scheme in a centralized quantum communication network via generalized GHZ states

Abstract: Quantum communication provides an enormous advantage over its classical counterpart: security of communications based on the very principles of quantum mechanics. Researchers have proposed several approaches for user identity authentication via entanglement. Unfortunately, these protocols fail because an attacker can capture some of the particles in a transmitted sequence and send what is left to the receiver through a quantum channel. Subsequently, the attacker can restore some of the confidential messages, giving rise to the possibility of information leakage. Here we present a new robust General N user authentication protocol based on N-particle Greenberger–Horne–Zeilinger (GHZ) states, which makes eavesdropping detection more effective and secure, as compared to some current authentication protocols. The security analysis of our protocol for various kinds of attacks verifies that it is unconditionally secure, and that an attacker will not obtain any information about the transmitted key. Moreover, as the number of transferred key bits N becomes larger, while the number of users for transmitting the information is increased, the probability of effectively obtaining the transmitted authentication keys is reduced to zero.

A replicated assessment and comparison of adaptation techniques for analogy-based effort estimation

Abstract: Variants of adaptation techniques have been proposed in previous studies to improve the performance of analogy-based effort estimation. The results of these studies are often contradictory and cannot simply be generalized because there are many uncontrollable source of variations between adaptation studies. The study presented in this paper has been carried out in order to replicate the assessment and comparison of different adaptation techniques utilised in analogy-based software effort prediction. Empirical evaluation of variants of adaptation techniques with Jack-knifing procedure have been carried out. Seven datasets come from PROMISE data repository were used for benchmarking. The results are also investigated within the presence/absence of feature subset selection algorithm. The current study permitted us to discover that linear adjustment approaches are more accurate than nonlinear adjustment because of the nature of the employed datasets that have, in most cases, normality characteristics.

In situ synthesis of graphene oxide/gold nanorods theranostic hybrids for efficient tumor computed tomography imaging and photothermal therapy

Abstract: Graphene oxide/gold nanorod (GO/GNR) nanohybrids were synthesized with a GO- and gold-seed-mediated in situ growth method at room temperature by mixing polystyrene sulfonate (PSS) functionalized GO, secondary growth solution, and gold seeds. Compared with ex situ preparation methods of GO/GNRs or graphene (G)/GNRs, the in situ synthesis of GO/GNRs addressed the issue of the aggregation of the GNRs before their attachment onto the GO. The method is straightforward and environment-friendly. The GO/GNRs showed a remarkable photothermal effect in vitro. The temperature of the GO/GNR nanohybrids increased from 25 to 49.9 °C at a concentration of 50 μg/mL after irradiation with an 808-nm laser (0.4 W/cm2) for 6 min. Additionally, the GO/GNRs exhibited good optical and morphological stability and photothermal properties after six cycles of laser irradiation. Upon injection of the GO/GNRs into xenograft tumors, excellent computed tomography (CT) imaging properties and photothermal effect were obtained. The preclinical CT agent iohexol was combined with the GO/GNRs and further enhanced CT imaging. Therefore, the GO/GNR nanohybrids have great potential for precise CT-image-guided tumor photothermal treatment.

Fast discharge process of layered cobalt oxides due to high Na⁺ diffusion.

Abstract: Sodium ion secondary battery (SIB) is a low-cost and ubiquitous secondary battery for next-generation large-scale energy storage. The diffusion process of large Na+ (ionic radius is 1.12 A), however, is considered to be slower than that of small Li+ (0.76 A). This would be a serious disadvantage of SIB as compared with the Lithium ion secondary battery (LIB). By means of the electrochemical impedance spectroscopy (EIS), we determined the diffusion constant (D) of Na+ in thin films of O3- and P2-type NaCoO2 with layered structures. We found that the D values (~ 0.5–1.5 × 10−10 cm2/s) of Na+ are higher than those (< 1 × 10−11 cm2/s) of Li+ in layered LiCoO2. Especially, the D values of O3-NaCoO2 are even higher than those of P2-NaCoO2, probably because O3-NaCoO2 shows successive structural phase transitions from the O3, O’3, P’3, to P3 phases with Na+ deintercalation. We further found that the activation energy (ED ~ 0.4 eV) for the Na+ diffusion is significantly low in these layered cobalt oxides. We found a close relation between the relative capacity and the renormalized discharge rate ( = L2/DT, where L and T are the film thickness and discharge time, respectively).