A ZnO nanowire-based photo-inverter with pulse-induced fast recovery.

Raza, Syed Raza Ali,Lee, Young Tack,Hosseini Shokouh, Seyed Hossein,Ha, Ryong,Choi, Heon-Jin,Im, Seongil RSC Pub 2013 Nanoscale Vol.5 No.22

<P>We demonstrate a fast response photo-inverter comprised of one transparent gated ZnO nanowire field-effect transistor (FET) and one opaque FET respectively as the driver and load. Under ultraviolet (UV) light the transfer curve of the transparent gate FET shifts to the negative side and so does the voltage transfer curve (VTC) of the inverter. After termination of UV exposure the recovery of photo-induced current takes a long time in general. This persistent photoconductivity (PPC) is due to hole trapping on the surface of ZnO NWs. Here, we used a positive voltage short pulse after UV exposure, for the first time resolving the PPC issue in nanowire-based photo-detectors by accumulating electrons at the ZnO/dielectric interface. We found that a pulse duration as small as 200 ns was sufficient to reach a full recovery to the dark state from the UV induced state, realizing a fast UV detector with a voltage output.</P>

Electrical joule heating for the isolation of ZnO nanowire channel and subsequent high-performance 1D circuit integration

Syed Raza Ali Raza,임준영,Zamir-ul-Hassan,임성길,이영탁 한국물리학회 2020 Current Applied Physics Vol.20 No.12

In this work, electrical Joule heating (J-H) was employed for the first time to electrically isolate ZnO nanowire FETs array for one dimensional (1D) logic applications without any physical and electrical damages. The electrical properties of the isolated nanowire FETs were found to be superior to non-isolated FETs came from the neighboring gate effect. Finally, we investigated ZnO nanowire-based NOT, NAND, and NOR logic gates with the J-H nanowire isolation technique. The isolated logic gates clearly show much lower output voltage off level than the non-isolated circuits thus resulting in more accurate and reliable 1D electronic applications.

Recent advancements in supercapacitor technology

Raza, Waseem,Ali, Faizan,Raza, Nadeem,Luo, Yiwei,Kim, Ki-Hyun,Yang, Jianhua,Kumar, Sandeep,Mehmood, Andleeb,Kwon, Eilhann E. Elsevier 2018 Nano energy Vol.52 No.-

<P><B>Abstract</B></P> <P>Supercapacitors (SCs) are attracting considerable research interest as high-performance energy storage devices that can contribute to the rapid growth of low-power electronics (e.g., wearable, portable electronic devices) and high-power military applications (e.g., guided missile techniques and highly sensitive naval warheads). The performance of SCs can be assessed in terms of the electrochemical properties determined through a combination between the electrode and the electrolyte materials. Likewise, the charge storage capacities of SCs can be affected significantly by selection of such materials (e.g., via surface redox mechanisms). Enormous efforts have thus been put to make them more competitive with existing options for energy storage such as rechargeable batteries. This article reviews recent advances in SC technology with respect to charge storage mechanisms, electrode materials, electrolytes (e.g., particularly paper/fiber-like 3D porous structures), and their practical applications. The challenges and opportunities associated with the commercialization of SCs are also discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> There has been great demand for a reliable technical platform for electrochemical storage. </LI> <LI> SCs are highly attractive option due to their fast storage capability and enhanced cyclic stability. </LI> <LI> This review covers the charge storage mechanisms of SCs along with comparison of selected SCs. </LI> <LI> We also discuss the technical challenges for developing SCs with high enough energy density. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Deep Foundation Testing using Immunity-based Displacement Measurement in Successive-Sparse Images

Ali Raza,Umair Aqil,Ummul Baneen,Muhammad Q. Saleem 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.10

This paper presents a new immunity-based approach to measure the displacement of nodes (or points of interest) in successive-yet-sparse images, in order to measure the settlement of deep-foundations under heavy loads. It is developed as a close-range photogrammetric technique to search the nodes, similar to immune-cells searching bacteria in their vicinity. The immunological concepts of chemotaxis, biased random walk, diffusion and inflammation are implemented herein to accomplish the task. The technique greatly reduces the errors and is also validated on site of a mega project to record the settlements in deep foundations. The accuracy levels are found to be conforming to ASTM's standards for static load testing, including both compression and lateral-load tests. Unlike other techniques, such as particle image velocimetry, this approach is able to handle successive-images with varying ΔTbetween them. Furthermore, the technique is completely autonomous and does not require any embedded instrumentation.

Efficacy of Nasobiliary Tubes and Biliary Stents in Management of Patients with Bile Leak after Liver Transplantation: A Systematic Review

Ali Raza,Anam Omer,Sara Iqbal,Vineet Gudsoorkar,Pramoda Koduru,Kumar Krishnan 대한소화기내시경학회 2019 Clinical Endoscopy Vol.52 No.2

Background/Aims: Bile leak is one of the most common complications of liver transplantation. The treatment options for bile leaksinclude conservative management, surgical re-intervention, percutaneous drainage and endoscopic drainage. We aimed to perform asystematic review to identify the effcacy of endoscopic treatment in the resolution of post-transplant bile leaks. Methods: Two independent reviewers performed systematic literature search in PubMed, ISI Web of Science, grey literature andrelevant references in May 2017. Human studies in English with documented post-liver transplant bile leaks were included. Results: Thirty-four studies were included in the final analysis. The pooled effcacy of biliary stents for the resolution of post-transplantbile leaks was 82.43% compared with 87.15% effcacy of nasobiliary tubes. The effcacy of biliary stents was lower for anastomotic leaks(69.23%) compared to T-tube (90.9%) or cut-surface/ cystic duct stump related leaks (92.8%). Similarly, the effcacy of nasobiliary tubewas also lower for anastomotic leaks (58.33%) compared to T-tube or cut-surface related leaks (100%). Conclusions: In this systematic review, the overall effcacy was 82.43% in biliary stent group, and 87.15% in nasobiliary tube group. Both biliary stent and nasobiliary tube were more effective in managing non-anastomotic leaks compared to anastomotic leaks.

Prediction of Axial Compressive Strength for FRP-Confined Concrete Compression Members

Ali Raza,Qaiser uz Zaman Khan,Afaq Ahmad 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.7

In the current work, a new strength model was proposed for capturing the ultimate axial strength of fiber reinforced polymers (FRP)-confined concrete compression members. First, a preliminary evaluation of previous strength models for estimating the wrapping effect of FRPs-confined concrete specimens was performed a large database of 520 confined concrete specimens was constructed with the detailed information of various geometric and material parameters of confined concrete specimens. Then, a strength model was suggested using regression analysis in MATLAB. The validation of the proposed strength model was made in two different approaches. In the first approach, the validation of proposed models was done by performing an experimental work of 6 carbon fiber reinforced polymer (CFRP) confined concrete cylinders and in the second approach, the nonlinear finite element analysis (NLFEA) via a general-purpose program ABAQUS was performed. After validation, a detailed parametric numerical study was done using the newly suggested strength model. A close agreement could be found between tests, NLFEA and theoretical results.

A Secure Authentication Protocol against the Co-located App Attack in BLE

Ali Raza,Safiullah Khan,Seong Oun Hwang 대한전자공학회 2020 IEIE Transactions on Smart Processing & Computing Vol.9 No.5

Bluetooth Low Energy (BLE) is used for periodic transmission of smaller data packages called attributes. BLE remains in sleep mode at all times except when participating in a data exchange, which reduces overall energy consumption. For secure communication, BLE devices need to pair first. The pairing has two or three phases. We say two or three phases because the third phase is optional and happens only if the devices are going to bond. The second pairing phase is made using a secure pairing scheme, but the third phase remains vulnerable to an attack named the co-located application (app) attack: a malicious app gets the same level of access to the paired protected data as the legitimate app. We provide an authentication protocol to mitigate this attack. Furthermore, we analyze the security of BLE communications after bonding, with or without our proposed protocol. Moreover, we also analyze the efficiency of the proposed protocol, and conclude that our proposed scheme makes BLE communications secure against the co-located app attack and is efficient enough to be practical.

Performance Measure of Hierarchical Structures for Multi-agent Systems

Ali Raza,Muhammad Iqbal,Jun Moon,Shun-Ichi Azuma 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.3

This paper investigates the robustness of linear consensus networks which are designed under a hierarchical scheme based on Cartesian product. For robustness analysis, consensus networks are subjected to additive white Gaussian noise. To quantify the robustness of the network, we use H2-norm: the square root of the expected value of the steady state dispersion of network states. We compare several classes of undirected and directed graph topologies. We show that the hierarchical structures, designed under the Cartesian product-based hierarchy, outperform the single-layer structures in terms of robustness. We provide simulations to support the analytical results presented in this paper.

Adaptive k-means clustering for Flying Ad-hoc Networks

( Ali Raza ),( Muhammad Fahad Khan ),( Muazzam Maqsood ),( Bilal Haider ),( Farhan Aadil ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.6

Flying ad-hoc networks (FANETs) is a vibrant research area nowadays. This type of network ranges from various military and civilian applications. FANET is formed by micro and macro UAVs. Among many other problems, there are two main issues in FANET. Limited energy and high mobility of FANET nodes effect the flight time and routing directly. Clustering is a remedy to handle these types of problems. In this paper, an efficient clustering technique is proposed to handle routing and energy problems. Transmission range of FANET nodes is dynamically tuned accordingly as per their operational requirement. By optimizing the transmission range packet loss ratio (PLR) is minimized and link quality is improved which leads towards reduced energy consumption. To elect optimal cluster heads (CHs) based on their fitness we use k-means. Selection of optimal CHs reduce the routing overhead and improves energy consumption. Our proposed scheme outclasses the existing state-of-the-art techniques, ACO based CACONET and PSO based CLPSO, in terms of energy consumption and cluster building time.

Salicylic acid and kinetin mediated stimulation of salt tolerance in cucumber (Cucumis sativus L.) genotypes varying in salinity tolerance

Ali Raza Gurmani,Sami Ullah Khan,Amjad Ali,Tehseen Rubab,Timothy Schwinghamer,Ghulam Jilani,Abid Farid,Jinlin Zhang 한국원예학회 2018 Horticulture, Environment, and Biotechnology Vol.59 No.4

Greenhouse studies were undertaken to evaluate the genetic performance of two cucumber genotypes (Long Green and Summer Green) at four salinity levels (0, 25, 50, and 100 mM NaCl). Seeds were pretreated with 50 mg salicylic acid (SA) L−1 and 25 mg kinetin (Kin) L−1. Under hydroponic conditions, seed pretreatment with Kin significantly increased shoot and root dry biomass and reduced the salt injury index in both genotypes. SA reduced the salt injury index of Long Green cucumbers. In a pot experiment, Kin treatment reduced Na+ and increased K+ concentration, photosynthesis, and chlorophyll content in both genotypes, compared to SA under saline soil conditions. Kin treatment improved fruit yield in both genotypes, while SA had a statistically significant effect on Long Green fruit yield. The application of SA and Kin enhanced salinity tolerance in both genotypes by the activation of antioxidants, especially superoxide dismutase, peroxidase, and catalase, which offset oxidative injury. Summer Green exhibited better salt tolerance and improved osmoregulation that resulted in higher fruit yield than Long Green. It was concluded that cucumber genotypes differed in salt tolerance, and seed pre-treatment with Kin minimized salt stress injury, even in sensitive genotype which could sustain crop production under saline conditions.