Variation in Structural, Electrical and Optical Properties of Selenium Nanowires After Irradiation with Ni6+ Ions

Suresh Panchal,R. P. Chauhan 대한금속·재료학회 2019 ELECTRONIC MATERIALS LETTERS Vol.15 No.2

The eff ect of Ni ion irradiation on selenium nanowires of 80 nm diameter is studied in the present work. Se nanowires wereprepared by using electrodeposition technique in polycarbonate membrane. Changes in the structural, optical and electricalproperties are studied using XRD, UV/Vis spectroscopy and current–voltage characteristics, of the pristine and irradiatedsamples. X-ray diff raction study confi rms the variation in peak intensity without any shifting in peak position. Variation intexture coeffi cient and grain size was clearly observed which is a consequence of changing plane orientation, irradiationinduced grain growth and grain fragmentation. A decrease in the optical band gap takes place due to interstitial energy bandstates in the vicinity of conduction and valence band. IVC also shows variation in the conductivity which is due to the generationof current carriers with the passage of energetic ions.

A Review to Mitigate the Carbon Dioxide Emission Level using Natural Fiber in 3D-printing Concrete

Priyanka Panchal(판찰 프리얀카),Choi, Myoung Sung(최명성) 한국콘크리트학회 2023 한국콘크리트학회 학술대회 논문집 Vol.35 No.1

Comparative evaluation of the effectiveness of two innovative methods in the management of anxiety in a dental office: a randomized controlled trial

Jay Panchal,Anup Panda,Krishna Trivedi,Deepika Chari,Rushita Shah,Binny Parmar 대한치과마취과학회 2022 Journal of Dental Anesthesia and Pain Medicine Vol.22 No.4

Background: The first dental experience is vital in molding a child's attitude towards dentistry and dental outcomes. The cooperation of a child during dental treatment is essential to render successful and high-quality treatment. Dental anxiety is common in children undergoing dental treatment. The success of pediatric dental treatments and patient comfort depends on controlling the levels of patient anxiety in clinical settings. This study aimed to compare the effectiveness of the recorded maternal voice and virtual cognitive tool (Roogies application) in the management of pediatric dental patients. Methods: The study was carried out with children aged of 4-7 years [n = 80, (40 male and 40 female)], without any past dental history, and were randomly allocated into two groups. After informed consent was obtained, the entire procedure was explained to the parents. Anxiety was assessed pre-, during, and post-treatment by measuring pulse rate, and recording Venham Picture Test (VPT) scores. Group A [n = 40; 20 boys and 20 girls)] was provided with a headphone that played a recorded maternal voice. Group B [n = 40; 20 boys and 20 girls)] was administered the virtual cognitive tool. After conditioning the children, oral prophylaxis was performed for both groups. A comparative evaluation was conducted for each treatment session. Results: The intra-group comparison of VPT scores and heart rate for patients assigned to the recorded maternal voice showed a statistically significant difference in dental anxiety (P-value ≤ 0.001). Conclusion: This study demonstrated that a reduction in dental anxiety with the help of recorded maternal voice forms an important component of non-pharmacological behavior management. Alternatively, the use of a virtual cognitive tool as an anxiety-reducing technique can also be advocated.

Texture Control Techniques for Improving Room Temperature Formability of Mg Alloys including Pre-twinning: A Review

Mahesh Panchal,K. R. Ravi,Lalit Kaushik,Rajesh Khatirkar,Shi‑Hoon Choi,Jaiveer Singh 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.12

Magnesium (Mg) alloys are the lightest among the structural metallic materials and have attracted great interest due to theirhigh specific strength and specific stiffness. However, Mg alloys show poor formability particularly at room temperature(RT), due to the development of strong basal texture and thus limiting their structural applications. Therefore, many techniquesbeing constantly proposed to alter the crystallographic texture in Mg alloys, such as microalloying, especially withrare-earth (RE) elements, severe plastic deformation (SPD), thermomechanical processing (TMP), pre-twinning/stretchingin the recent past. Pre-twinning remains the most effective technique that controls the crystallographic texture in Mg alloysby introducing 1012 extension twins (ETs) which work out for alloys prepared through various prior processing conditionsand compositions. Interestingly, only a small fraction of ETs during pre-twinning imparts significant improvement in the RTstretch formability. Therefore, this manuscript critically reviews the underlying mechanisms of pre-twinning and texturecontrol via practical pre-twinning methods such as in-plane compression and compares its effectiveness with other texturecontrol methods through alloy design, TMP, and SPD processes. In addition, the effect of initial microstructure and variousdeformation conditions on the contribution of twin, twin-orientation control during thermal treatment and also their influenceon the RT stretch formability are discussed.

Seismic Response of Liquid Storage Steel Tanks with Variable Frequency Pendulum Isolator

V. R. Panchal,R. S. Jangid 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.6

The seismic response of liquid storage steel tanks (slender and broad) isolated with Variable Frequency Pendulum Isolators (VFPIs) is investigated under normal component of six near-fault ground motions. The continuous liquid mass is lumped as convective mass, impulsive mass and rigid mass. The corresponding stiffness associated with these lumped masses is worked out depending upon the properties of the tank wall and liquid mass. The frictional forces mobilized at the interface of the VFPI are assumed to be velocity independent. The governing equations of motion of liquid storage steel tanks isolated with the VFPIs are derived and solved in the incremental form using Newmark’s step-by-step method assuming linear variation of acceleration over small time interval. For comparative study, the seismic response of liquid storage steel tanks with the VFPIs is compared with that of the same liquid storage steel tanks isolated using the Friction Pendulum Systems (FPSs). In order to measure the effectiveness of isolation system, the seismic response of isolated steel tanks is compared with that of the non-isolated steel tanks. Further, a parametric study has been carried out to critically examine the behaviour of liquid storage steel tanks isolated with VFPIs. The important parameters considered are the friction coefficient of the VFPI, the Frequency Variation Factor (FVF) of the VFPI and the tank aspect ratio. The difference between the liquid storage tanks isolated with the VFPI and the FPS isolators subjected to the harmonic and far-field ground motions was also investigated in this study. Effect of vertical component of ground motions on the behaviour of the VFPI-isolated liquid storage tanks is investigated under triaxial ground excitations by considering the interaction of forces in two orthogonal directions. From these investigations, it is concluded that seismic response, viz. the base shear, the sloshing displacement and the impulsive displacement, of liquid storage steel tanks during near-fault ground motions can be controlled within a desirable range with the installation of the VFPI. Under strong harmonic excitations, the base shear of the VFPI reduces than that of the FPS whereas the sloshing displacement, the impulsive displacement and the isolator displacement of the VFPI exceeds than that of the FPS. It is also found that the isolation by the FPS and VFPI isolators has almost the same effect in the tank to the far-field ground motions. The triaxial ground motions have noticeable effect on the response of the VFPI-isolated liquid storage tanks relative to unilateral ground motion and if ignored, the sliding displacement and base shear will be underestimated.

Behaviour of asymmetric building with double variable frequency pendulum isolator

V.R. Panchal,D.P. Soni,B.B. Mistry 국제구조공학회 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.34 No.1

Presented in this paper is the behaviour of asymmetric building isolated by the double variable frequency pendulum isolator (DVFPI). The DVFPI is an adoption of single variable frequency pendulum isolator (VFPI). The geometry and coefficient of friction of top and bottom sliding surfaces can be unequal. The governing equations of motion of the building-isolation system are derived and solved in incremental form. The analysis duly considers the interaction of frictional forces in the two principal directions developed at each sliding surface of the DVFPI. In order to investigate the behaviour of the base isolation using the DVFPI, the coupled lateral-torsional response is obtained under different parametric variations for a set of six far-fault earthquake ground motions and criterion to optimize its performance is proposed. Further, influences of the initial time period, coefficient of friction and frequency variation factors at the two sliding surfaces are investigated. The numerical results of the extensive parametric study help in understanding the torsional behaviour of the structure isolated with the double sliding surfaces as in the DVFPI. It is found that the performance of the DVFPI can be optimized by designing the top sliding surface initially softer and smoother relative to the bottom one.

Seismic Behaviour of Isolated Fluid Storage Tanks: A-state-of-the-art Review

V. R. Panchal,D.P. Soni 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.4

An updated state-of-the-art-review of the behaviour of the isolated fluid storage tanks to seismic excitation is presented. The mainobjective of review is to provide assistance to current research and engineering practice on base isolated fluid storage tanks. Thereview includes the literature on theoretical aspects of seismic isolation, parametric behaviour of isolated fluid storage tanks andexperimental studies to verify some of the theoretical findings. Aspects for future research in the area of isolation of fluid storagetanks are also presented.

AN EFFICIENT FINITE ELEMENT MODEL FOR ANALYSIS OF SINGLE WALLED BORON NITRIDE NANOTUBE-BASED RESONANT NANOMECHANICAL SENSORS

MITESH B. PANCHAL,S. H. UPADHYAY,S. P. HARSHA 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.1

In this paper, the dynamics analysis of single walled boron nitride nanotubes (SWBNNT) as a resonant nanomechanical sensor by using the finite element method has been reported. Molecular structural mechanics-based finite element model (FEM) has been developed by using three-dimensional elastic beams and point masses, such that the proximity of the model to the actual atomic structure of nanotube is significantly retained. Different types of armchair layups of SWBNNTs are considered with cantilevered and bridged end constraints. By implementing the finite element simulation approach, the resonant frequency shift-based mass sensitivity analysis is performed for both types of end constraints for considered armchair form of the SWBNNTs with different aspect ratios. For both types of end constraint, continuum mechanics-based analytical formulations, considering effective wall thickness of nanotubes are used to validate the present FEM-based simulation approach. The intermediate landing position of the added mass is analyzed, considering variations in resonant frequency shifts of the different fundamental modes of vibrations for both types of end constraints. The FEM-based simulation results for both types of end constraints found in good agreement with the continuum mechanics-based analytical results for the aspect ratio of range of 9–15. The mass sensitivity limit of 10-1 zg is achieved for SWBNNT-based resonant nanomechanical sensors. The resonant frequency shift for higher-order fundamental vibrational modes become stable as the attached mass moves away from the fixed ends for particular magnitude of attached mass. The present finite element-based approach is found to be effectual in terms of dealing different atomic structures, boundary conditions and consideration of added mass to analyze the dynamic behavior of the SWBNNT-based resonant nanomechanical sensors.

An Inversion Formula for the Distributional Generalized Hankel Transform

D.K. Panchal...et al KYUNGPOOK UNIVERSITY 1998 Kyungpook mathematical journal Vol.38 No.1

A complex inversion formula [9] for the generalized Hankel transformation involving Meijer's G-function as kernel is extended to generalized functions interpreting convergence in the weak distributional sense.

Improvement of dissolution rate of tacrolimus by solid dispersion technique

Shital S. Panchal,Tejal A. Mehta,Pranav V. Patel 한국약제학회 2013 Journal of Pharmaceutical Investigation Vol.43 No.1

Tacrolimus has a poor solubility in water ranging from 4 to 12 lg mL-1. The mean bioavailability is *21 %.The present study was carried out with a view to enhance the dissolution rate of poorly water-soluble drug tacrolimus using Gelucire 44/14 and Gelucire 50/13 as carriers and lactose monohydrate as an adsorbent. A combination of melt and adsorption techniques was employed for the preparation of solid dispersions (SD) to make final product easy for handling. Phase solubility study was conducted to evaluate the effect of carriers on aqueous solubility of tacrolimus. In order to elucidate the mechanism of dissolution enhancement, solid state characteristics were investigated using Fourier transform infrared spectroscopy,differential scanning calorimetry and powder X-ray diffraction. Mathematical modeling of in vitro dissolution data indicated the best fitting with Korsemeyer–Peppas model and the drug release kinetics primarily as Fickian/anomalous diffusion. All prepared solid dispersions showed dissolution improvement compared to pure drug, with Gelucire 50/13 as the superior carrier over Gelucire 44/14. Almost similar dissolution profile was obtained as a function of storage time; this can be explained by no change in XRD and DSC pattern after 45 days storage period.