Influence of Aminosilane Coupling Agent on Aromatic Polyamide/Intercalated Clay Nanocomposites

Alvi, Muhammad Usman,Zulfiqar, Sonia,Yavuz, Cafer T.,Kweon, Hee-Seok,Sarwar, Muhammad Ilyas American Chemical Society 2013 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.52 No.21

<P>Aminosilane grafted and diamine modified reactive montmorillonite was exploited to generate aromatic polyamide based nanocomposites. For better compatibility, the hydrophilic nature of montmorillonite was changed into organophilic using 1,4-phenylenediamine, and the hydroxyl groups present on the clay surface and edges were used to graft 3-aminopropyltriethoxysilane (APTS) on clay sheets. The dispersion of clay was monitored in the polyamide obtained from 1,4-phenylenediamine, 4,4′-oxydianiline, and isophthaloyl chloride. These chains were converted into carbonyl chloride ends to interact with free amine groups of grafted APTS and diamine. Thin films were probed for FTIR, XRD, SEM, TEM, tensile testing, TGA, and DSC measurements. The results described ample dispersion of clay in the nanocomposites with tensile strength increased 110% and elongation increased 172% upon the addition of 4–6 wt % clay. Thermal decomposition temperatures of the nanocomposites were in the range 425–480 °C. The glass transition temperature increased up to 142.4 °C with 6 wt % addition of organoclay.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/iecred/2013/iecred.2013.52.issue-21/ie400463z/production/images/medium/ie-2013-00463z_0013.gif'></P>

Computational design and characterization of a subcritical reactor assembly with TRIGA fuel

Alvie Asuncion-Astronomo,Ziga Stancar,Tanja Goricanec,Luka Snoj 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.2

The TRIGA fuel of the Philippine Research Reactor-1 (PRR-1) will be used in a subcritical reactor assembly(SRA) to strengthen and advance nuclear science and engineering expertise in the Philippines. SRA offersa versatile and safe training and research facility since it can produce neutrons through nuclear fissionreaction without achieving criticality. In this work, we used a geometrically detailed model of the PRR-1TRIGA fuel to design a subcritical reactor assembly and calculate physical parameters of different fuelconfigurations. Based on extensive neutron transport simulations an SRA configuration is proposed,comprising 44 TRIGA fuel rods arranged in a 7 7 square lattice. This configuration is found to have amaximum keff value of 0:95001±0:00009 at 4 cm pitch. The SRA is characterized by calculating the 3-dimensional neutron flux distribution and neutron spectrum. The effective delayed neutron fraction andmean neutron generation time of the system are calculated to be 748 pcm±7 pcm and 41 ms, respectively. Results obtained from this work will be the basis of the core design for the subcritical reactorfacility that will be established in the Philippines.

Motivation Versus Intention of Sharing Fake News Among Social Media Users during the Pandemic - A SEM Model

Alvi, Irum,Saraswat, Niraja World Association for Triple Helix and Future Stra 2021 Journal of Contemporary Eastern Asia Vol.20 No.2

Are intentions important in deciding the outcome of an action such as sharing misinformation among social media users during the pandemic? What is their role and how far they are important for the very act of fake sharing news? The social media users' actions on the social platform are determined by what they plan to do themselves; however, their motivation has an immense role to play in the dissemination of fake news on social media. The study proposes a conceptual model for understanding how select factors affect fake news sharing motivation and intentions of social media users. The study scrutinizes the relationship between content and context, fear of missing out (FoMO), news verification and news sharing gratification on the motivation and intention of social media users of networked Asian society. Empirical Data were drawn from social media users (N = 243) from India, using an online questionnaire based on prior studies and structural equation modeling (SEM) approach was used to analyze the data collected. Results indicate that news content, news verification, and news sharing gratification have a direct and positive relationship with sharing motivation. On the other hand, news context and content, FoMO and news sharing gratification have a positive significant relationship with sharing intention. Likewise, it was discovered that news verification will decrease sharing intention of the social media users. However, news context, that is the pandemic in the case of the present study and FoMO were not identified as determinant variables for sharing motivation among social media users. The research limitations and further scope were discussed.

ON ATTENUATION OF MORAL HAZARD IN RISK SHARING IN POOR URBAN ECONOMIES

Eskander Alvi,Seife Dendir 한국국제경제학회 2008 International Economic Journal Vol.22 No.4

This paper examines how risk sharing is shaped by moral hazard and enforcement concerns. The existing literature mostly looks at each concern in isolation and misses out on an interesting tradeoff between insurance and production (effort) that is introduced by jointly incorporating moral hazard and enforcement problems. We show that self-enforcement of contracts requires reduced insurance which in turn softens the moral hazard stance, thereby enhancing effort. Households therefore work harder and produce more output, though they are less insured. This offers an explanation of why informal risk sharing persists despite potentially significant monitoring and enforcement difficulties.

Enhanced TDMA based MAC Protocol for Adaptive Data Control in Wireless Sensor Networks

Ahmad Naseem Alvi,Safdar Hussain Bouk,Syed Hassan Ahmed,Muhammad Azfar Yaqub,Nadeem Javaid,김동균 한국통신학회 2015 Journal of communications and networks Vol.17 No.3

In this paper, we propose an adaptive time division multiple access based medium access control (MAC) protocol, called bitmap-assisted shortest job first based MAC (BS-MAC), for hierarchical wireless sensor networks (WSNs). The main contribution of BS-MAC is that: (a) It uses small size time slots. (b) The number of those time slots is more than the number of member nodes. (c) Shortest job first (SJF) algorithm to schedule time slots. (d) Short node address (1 byte) to identify members nodes. First two contributions of BS-MAC handle adaptive traffic loads of all members in an efficientmanner. The SJF algorithm reduces node’s job completion time and to minimize the average packet delay of nodes. The short node address reduces the control overhead and makes the proposed scheme an energy efficient. The simulation results verify that the proposed BS-MAC transmitsmore data with less delay and energy consumption compared to the existing MAC protocols.

Structural, optical and electrical properties of laser irradiated Pb doped GaeSe chalcogenide thin films

M.A. Alvi 한국물리학회 2013 Current Applied Physics Vol.13 No.3

Using the Transverse Electrical Excitation at Atmospheric Pressure (TEA) nitrogen laser, we had irradiated the amorphous thin films of Ga10Se81Pb9 chalcogenide glass and the results have been discussed in terms of the structural aspects of Ga10Se81Pb9 glass. The observed changes are associated with the interaction of the incident photon and the lone-pairs electrons which affects the band gap. The X-ray structural characterization revealed the amorphous nature of as prepared films and polycrystalline nature of the laser irradiated films. The optical band gap of these thin films is measured by using the absorption spectra as a function of photon energy in the wavelength region 400-1200 nm. It is found that the optical band gap decreases while the absorption coefficient increases with increasing the irradiation time. The decrease in the optical band gap has been explained on the basis of change in nature of films, from amorphous to polycrystalline state, with the increase in exposure time. The dc conductivities and activation energies of these thin films are measured in temperature range 303e403 K. It has been found that the activation energy in Ga10Se81Pb9 chalcogenide thin films decreases whereas the dc conductivity increases at each temperature by increasing the irradiation time.

An Objective and Reliable Method for Identifying Sarcopenia in Lumbar Spine Surgery Patients: Using Morphometric Measurements on Computed Tomography Imaging

Marko Tomov,Mohammed Ali Alvi,Mohamed Elminawy,Bradford Currier,Michael Yaszemski,Ahmad Nassr,Paul Huddleston,Arjun Sebastian,Mohamad Bydon,Brett Freedman 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.6

Study Design: A retrospective observational study.Purpose: Establish a quantifiable and reproducible measure of sarcopenia in patients undergoing lumbar spine surgery based on morphometric measurements from readily available preoperative computed tomography (CT) imaging. Overview of Literature: Sarcopenia—the loss of skeletal muscle mass—has been linked with poor outcomes in several surgical disciplines; however, a reliable and quantifiable measure of sarcopenia for future assessment of outcomes in spinal surgery patients has not been established.Methods: A cohort of 90 lumbar spine fusion patients were compared with 295 young, healthy patients obtained from a trauma da¬tabase. Cross-sectional vertebral body (VB) area, as well as the areas of the psoas and paravertebral muscles at mid-point of pedicles at L3 and L4 for both cohorts, was measured using axial CT imaging. Total muscle area-to-VB area ratio was calculated along with intraclass correlation coefficients for interobserver and intraobserver reliability. Finally, T-scores were calculated to help identify those patients with considerably diminished muscle-to-VB area ratios.Results: Both muscle mass and VB areas were considerably larger in males compared with those in females, and the ratio of these two measures was not enough to account for large differences. Thus, a gender-based comparison was made between spine patients and healthy control patients to establish T-scores that would help identify those patients with sarcopenia. The ratio for paravertebral muscle area-to-VB area at the L4 level was the only measure with good interobserver reliability, whereas the other three of the four ratios were moderate. All measurements had excellent correlations for intraobserver reliability.Conclusions: We postulate that a patient with a T-score <−1 for total paravertebral muscle area-to-VB area ratio at the L4 level is the most reliable method of all our measurements that can be used to diagnose a patient undergoing lumbar spine surgery with sarcopenia.

First monosegment liver resection in newly established hospital

Muhammad Zakria,Umar Alvi 한국간담췌외과학회 2016 한국간담췌외과학회 학술대회지 Vol.2016 No.4

Assessment of the quality of life in maxillectomy patients : a longitudinal study

Pradeep Kumar,Habib Ahmad Alvi,Jitendra Rao,Balendra Pratap Singh,Sunit Kumar Jurel,Lakshya Kumar,Himanshi Aggarwal 대한치과보철학회 2013 The Journal of Advanced Prosthodontics Vol.5 No.1

PURPOSE. To longitudinally assess the quality of life in maxillectomy patients rehabilitated with obturator prosthesis. MATERIALS AND METHODS. Thirty-six subjects were enrolled in the span of 16 months, out of which six were dropouts. Subjects (age group 20-60 years) with maxillary defects, irrespective of the cause, planned for definite obturator prosthesis, were recruited. The Hindi version of European Organization for Research and Treatment of Cancer, Head and Neck version 1 of Quality of Life Questionnaire was used before surgical intervention and one month after definitive obturator. Questionnaire includes 35 questions related to the patient’ physical health, well being, psychological status, social relation and environmental conditions. The data were processed with statistical package for social science (SPSS). Probability level of P<.05 was considered statistically significant. RESULTS. The quality of life after rehabilitation with obturator prosthesis was 81.48% (±13.64) on average. On item-level, maximum mean scores were obtained for items problem with teeth (1.87 ± 0.94), pain in mouth (1.80 ± 0.92), trouble in eating (1.70 ± 0.88), trouble in talking to other people (1.60 ± 1.22), problems in swallowing solid food (1.57 ± 1.22) and bothering appearance (1.53 ± 1.04); while minimum scores were obtained for the items coughing (1.17 ± 0.38), hoarseness of voice (1.17 ± 0.53), painful throat (1.13 ± 0.43), trouble in having social contacts with friends (1.10 ± 0.40) and trouble having physical contacts with family or friends (1.10 ± 0.31). CONCLUSION. Obturator prosthesis is a highly positive and non-invasive approach to improve the quality of life of patients with maxillectomy defects.

Antibiotics for Penicillin : Sensitive Patients

Spelman, Denis W.,Kucers, Alvis Medical Publications Korea 1978 Medical Progress Vol.5 No.8