Experimental and theoretical study of BF3 detector response for thermal neutrons in reflecting materials

Rubina Nasir,Faiza Aziz,Sikander M. Mirza,Nasir M. Mirza 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.3

Experimental measurements of the response of BF3 detector to a 3 Ci AmeBe neutron source for threedifferent reflecting materials, i.e., aluminum, wood, and Perspex of varying thicknesses have been carriedout. The varying contribution of wall effect to the response due to change in active volume of the detectorhas also been determined experimentally. Then, a Monte Carlo code has been developed for the calculationof the neutron response function of the BF3 detector using source biasing and importance sampling. This code simulates the BF3 detector response exposed to the neutron field in a three-dimensionalsource, detector, and reflecting medium configurations. The results of simulation have been comparedwith the corresponding experimental measurements and are found to be in good agreement. Theexperimental neutron albedo measurements for various values of Perspex thickness show saturatingbehavior, and results agree very well with the data obtained by Monte Carlo simulation.

Effect of Kinetic Parameters on Simultaneous Ramp Reactivity Insertion plus Beam Tube Flooding Accident in a Typical Low Enriched U3Si2-Al Fuel based MTR-Type Research Reactor

Rubina Nasir,Sikander M. Mirza,Nasir M. Mirza 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.4

This work looks at the effect of changes in kinetic parameters on simultaneous reactivityinsertions and beam tube flooding in a typical material testing reactor-type researchreactor with low enriched high density (U3Si2-Al) fuel. Using a modified PARET code,various ramp reactivity insertions (from $0.1/0.5 s to $1.3/0.5 s) plus beam tube flooding($0.5/0.25 s) accidents under uncontrolled conditions were analyzed to find their effects onpeak power, net reactivity, and temperature. Then, the effects of changes in kinetic parametersincluding the Doppler coefficient, prompt neutron lifetime, and delayed neutronfractions on simultaneous reactivity insertion and beam tube flooding accidents wereanalyzed. Results show that the power peak values are significantly sensitive to theDoppler coefficient of the system in coupled accidents. The material testing reactor-typesystem under such a coupled accident is not very sensitive to changes in the promptneutron life time; the core under such a coupled transient is not very sensitive to changesin the effective delayed neutron fraction.

Cultural Exchange and Educational Activities : Experiences of Muslim International Students in South Korea

Hamza Nasir,Nasir Yasin,Sana ur Rehman 대구대학교 다문화사회정책연구소 2023 현대사회와 다문화 Vol.13 No.2

This paper discusses the experiences of international students in Korea and their involvement in various educational activities. The paper begins with a brief introduction of the students and their journey to Korea, followed by an exploration of the value of religion and its role in their life as Muslim international students. The paper then delves into the events in which the students participated, including a cross-cultural activity, a walk in the KNU, a food stall at the KNU fair, a visit to the mosque, a Daehyeon-dong movie day, an international cooking program, and an Apsan observatory hiking event. The paper highlights the cultural exchange and interactions that took place during these events, as well as the significance of such activities in promoting cross-cultural understanding and appreciation. The paper also acknowledges the efforts of the organizers and the role played by the university in facilitating these activities. Overall, the paper emphasizes the importance of such events in promoting cultural diversity and understanding in today’s globalized world.

Degree of Hydration and Compressive Strength of Conditioned Samples Made of Normal and Blended Cement System

Nasir Shafiq 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.7

In this paper; results of the degree of hydration of the pastes and the compressive strength of the 50 mm cubes prepared with the 100% cement and fly ash blended cement were determined. 24 hours after casting mortar cubes and the paste samples were cured for 28 days in the fog room. After 28 days curing, a set of three cubes and a paste sample was dried in the 100%, 75%, 65%, 40% and 12% ambient relative humidity at the constant temperature of 27oC. Drying conditions showed significant effects on the compressive strength and the degree of hydration. Highest compressive strength of 70 MPa was measured of mortar cubes dried in 100% RH;similarly, 97% degree of hydration was obtained for 100% cement samples dried in the 100% RH. For mortar cubes dried in 12%RH, the compressive strength was measured between 47 and 53 MPa. The similar paste samples showed the maximum degree of hydration as 81%. Statistically valid correlations were obtained between the degree of hydration and the compressive strength of normal and blended cement system.

On Lebesgue nonlinear transformations

Nasir Ganikhodjaev,Ramazon Muhitdinov,M. Saburov 대한수학회 2017 대한수학회보 Vol.54 No.2

In this paper, we introduce a quadratic stochastic operators on the set of all probability measures of a measurable space. We study the dynamics of the Lebesgue quadratic stochastic operator on the set of all Lebesgue measures of the set $[0,1]$. Namely, we prove the regularity of the Lebesgue quadratic stochastic operators.

Viral evolution : Primordial cellular origins and late adaptation to parasitism

Nasir, Arshan,Kim, Kyung Mo,Caetano-Anollé,s, Gustavo Landes Bioscience 2012 Mobile genetic elements Vol.2 No.5

<P>Explaining the origin of viruses remains an important challenge for evolutionary biology. Previous explanatory frameworks described viruses as founders of cellular life, as parasitic reductive products of ancient cellular organisms or as escapees of modern genomes. Each of these frameworks endow viruses with distinct molecular, cellular, dynamic and emergent properties that carry broad and important implications for many disciplines, including biology, ecology and epidemiology. In a recent genome-wide structural phylogenomic analysis, we have shown that large-to-medium-sized viruses coevolved with cellular ancestors and have chosen the evolutionary reductive route. Here we interpret these results and provide a parsimonious hypothesis for the origin of viruses that is supported by molecular data and objective evolutionary bioinformatic approaches. Results suggest two important phases in the evolution of viruses: (1) origin from primordial cells and coexistence with cellular ancestors, and (2) prolonged pressure of genome reduction and relatively late adaptation to the parasitic lifestyle once virions and diversified cellular life took over the planet. Under this evolutionary model, new viral lineages can evolve from existing cellular parasites and enhance the diversity of the world’s virosphere.</P>

Flowering and Fruiting in Olives in Some Subtropical Climates Where Typical Chilling Required for Flowering Does Not Occur

Nasir S.A. Malik,Joe M. Bradford 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Adaptive Fractional Order PID Controller Based MPPT for PV Connected Grid System Under Changing Weather Conditions

Nasir Ali,Rasool Imran,Sibtain Daud,Kamran Raheel 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.5

This paper is presenting an Adaptive Fractional Order PID (AFOPID) controller for PV connected grid system. The proposed controller is designed to harvest maximum power from the PV source. AFOPID controller contain the property of conventional PID controller, where the controller contains an adaptive property to optimize gain parameter on the basis of generator and grid side parameter in view. In the suggested work, the AFOPID controller imparted with the characteristic to get tune with particle swarm optimization to track maximum power point tracking, dc link voltage, and current control and quadrature axis modeling. Furthermore, the current control functionalities are performed through an AFOPID, where the controlling parameters are updated by measured error at every instant. The aim of this research is to attain maximum power from the PV source under varying weather conditions with minimum total harmonic distortion, which validate the performance of the proposed controller. The proposed work is compared with, FOPID, FLC, PI, GA and ACO tune FOPID controllers.

Ising Model on the Cayley Tree with Competing Interactions up to the Third Nearest-neighbors with Spins Belonging to Different Branches of the Tree

Nasir Ganikhodjaev,Mohd Hirzie Mohd Rodzhan 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.8

We study the phase diagram of the Ising model on the Cayley tree with competing interactions up to the third nearest-neighbors with spins belonging to different branches of the tree. In addition to the expected ferromagnetic, anti-ferromagnetic and paramagnetic phases, we present a new paramodulated phase. Moreover, the transition lines are analyzed and they are in agreement with the lines obtained numerically. Lastly, the stability of the anti-ferromagnetic phase was studied in detail by investigating the Lyapunov exponent associated with the corresponding dynamical system.

Effect of alkaline activators on the fresh properties and strength of silico-manganese fume-slag activated mortar

Nasir, Muhammad,Johari, Megat Azmi Megat,Yusuf, Moruf Olalekan,Maslehuddin, Mohammed,Al-Harthi, Mamdouh A. Techno-Press 2020 Advances in concrete construction Vol.10 No.5

This study investigated the effect of alkaline activators - NaOH_aq (NH) (NH: 0-16 M) and Na₂SiO_3aq (NS) (NS/NH: 0-3.5) in the synthesis of silico-manganese fume (SMF) and ground blast furnace slag (BFS) blended alkali-activated mortar (AASB). The use of individual activator was ineffective in producing AASB of sufficient fresh and hardened properties, compared to the synergy of both activators. This may be attributed to incomplete dissolution and condensation of oligomers required for gelation of the binder. An inverse relationship was noted among the fresh properties and the NH concentration or NS/NH ratio. This was influenced by the dissolution and condensation of silicate monomers under polymerization process. The maximum 28-day strength of ~45 MPa, setting time of 60 min and flow of 182 mm was obtained with the use of combined activators (10M-NH and NS/NH=2.5). The combined activators at NS/10M-NH=2.5 constituted SiO₂/Na₂O, H₂O/Na₂O and H₂O/SiO₂ molar ratio of 1.61, 17.33 and 10.77, respectively. This facilitated the formation of C-S-H, C/K-A-S-H and C-Mn-S-H in the framework together with an increase in the crystallinity due to more silicate re-organization within the aluminosilicate chain. On comparison of the high concentrated with mild alkali synthesized product, it revealed that the concentration of OH^- and Si monomers together with alkali metals influenced the dissolution of precursors and embedment of the constituent elements in the polymeric matrix. These factors eventually contributed to the microstructural densification of the mortar prepared with NS/10M-NH=2.5 thereby enhancing the compressive strength.