Experimental Tests on Extended End-Plate Connections with Variable Parameters

Mahmood Md Tahir1,Md Azman Hussein 한국강구조학회 2008 International Journal of Steel Structures Vol.8 No.4

Typically, steel frames are designed either using the approach of pin joint for simple construction or rigid joint for continuous construction. However, in actual situation most of connections are classified as semi-rigid joint or partial strength which has been recognised and encouraged by Eurocode 3 in semi-continuous construction. Eight experimental tests have been carried out for extended end-plate connections consist of variable parameters such as size and thickness of end-plate, size and number of bolts, size of columns, and beams. The tests were set-up using local hot-rolled steel sections known as Perwaja sections for both beams and columns instead of typical British sections. Geometric parameters such as the thickness of end-plate, the number and size of bolts and the use of deeper beam have contributed significantly to the increase in moment resistance and stiffness of the connections. The study concluded that all the tested extended end-plate connections are eligible to be classified as partial strength connections and the results of maximum moment resistance showed good agreement between experimental and predicted component method in most cases.

Stock Market Response to Terrorist Attacks: An Event Study Approach

TAHIR, Safdar Husain,TAHIR, Furqan,SYED, Nausheen,AHMAD, Gulzar,ULLAH, Muhammad Rizwan Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.9

The purpose of this research study is to examine the stock market's response to terrorist attacks. The study uses data of terrorist attacks in different parts of the country (Pakistan) from June 1, 2014 to May 31, 2017. The event window procedure applies to a 16-day window in which 5 days before and 10 days after the attack. In addition, several event windows have been built to test the response of the Pakistan Stock Exchange. KSE-100 index is taken as proxy of response. The total terrorist attacks are classified into four categories: attacks on law enforcement agencies, attacks on civilians, attacks on special places and attacks on politicians, government employees and bureaucrats. The standard market model is used to estimate the abnormal return of the Pakistan Stock Exchange, which takes 252 business days each year. Furthermore, BMP test is used to check statistical significance of cumulative abnormal rate of return (CAAR). The results of this study reveal that total number of terrorist attacks and attacks on law enforcement agencies show long-term effects on Pakistan stock exchange. However, attacks on civilians, attacks on special places and attacks on politicians, government employees and bureaucrats have little effect on the Pakistan Stock Exchange.

Privacy-preserving COVID-19 Contact Tracing using Blockchain

Shahzaib Tahir,Hasan Tahir,Ali Sajjad,Muttukrishnan Rajarajan,Fawad Khan 한국통신학회 2021 Journal of communications and networks Vol.23 No.5

The outbreak of the COVID-19 virus has causedwidespread panic and global initiatives are geared towards treatmentand limiting its spread. With technological advancements,several mechanisms and mobile applications have been developedthat attempt to trace the physical contact made by a personwith someone who has been tested COVID-19 positive. Whiledesigning these apps, user’s privacy has been an afterthoughtand has resulted in mass violations of privacy of the public andthe patients. A total of 32 countries have designed apps andrely on them as a strategy to flatten the pandemic curve. Alongwith lack of privacy, these methodologies are centralized, wherethey are fully controlled by the government and the healthcareproviders. Owing to these and many other concerns, peopleare hesitant in the adoption of these technologies. This paperpresents a detailed analysis of user tracking apps belongingto 32 countries, thus demonstrating that they collect personaldata and are a gross violation of user privacy. This paperpresents a novel architecture for the efficient, effective andprivacy-preserving contact tracing of COVID-19 patients usingblockchain. The proposed architecture preserves the privacy ofindividuals and their contact history by encrypting all the dataspecific to an individual using a privacy-preserving Homomorphicencryption scheme and storing it on a permissioned blockchainnetwork. The contacts made with a COVID-19 positive patientare identified by performing search queries directly over theHomomorphic encrypted data stored in the blocks. Therefore,only those contacts that are suspected to be COVID-19 positivemay be decrypted by the healthcare professional or governmentfor further contact tracing/ diagnosis and COVID-19 testing;thereby leading to enhanced privacy.

4-Hexylresorcinol sensor development based on wet-chemically prepared Co3O4@Er2O3 nanorods: A practical approach

Tahir Ali Sheikh,Mohammed M. Rahman,Abdullah M. Asiri,Hadi M. Marwani,Md. Rabiul Awual 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.66 No.-

In this approach, Co3O4@Er2O3 nanorods (NRs) were prepared by a wet-chemical method using reducing agents in alkaline medium. The resulting nanoparticles were characterized in details by UV/Vis and FT-IR spectroscopy, X-ray powder diffraction, Elemental dispersive analysis (EDS) coupled with field-emission scanning electron microscopy (FESEM). Co3O4@Er2O3NRs were deposited on a glassy carbon electrode (GCE) to give a selective sensor with a fast response toward 4-hexyl resorcinol (4-HR) in phosphate buffer phase (PBS) by electrochemical approach. The 4-HR sensor also displays good sensitivity, large linear dynamic range, lowest detection limit, and long-term stability, and enhanced electrochemical response. The calibration plot is linear over the 0.1 nM–0.01 M 4-HR concentration range. The sensitivity is ∼14.765 μAμM−1cm−2, and the detection limit is 64.29 pM (signal-to-noise ratio, at a SNR of 3). We also discuss possible future prospective uses of this doped metal oxide semiconductor nanomaterial in terms of chemical sensing.

Antihematotoxic Role of Bunium persicum Seed Differential Extracts in Animal Model: Reactive Oxygen Species Might Be a Contributor

Tahir Ali,Kamran Saeed,Muhammad Abdullah,Iram Murtaza 질병관리본부 2014 Osong Public Health and Research Persptectives Vol.5 No.6

Objectives: Humans have been using plants as natural medicines since prehistoric times. Bunium persicum is a rich source of oils with different biological activities such as antioxidative and antimicrobial activities. The aim of this study is to evaluate the antihematotoxic and antioxidative effects of the differential extracts of B. persicum against leukemic blood induced hematotoxicity in an animal model. Methods: This study was performed on animals, which were divided into several groups: normal control, disease control, and groups that were administered with differential extracts of plants. We measured the concentration of free radical [reactive oxygen species (ROS)] and hematological parameters as blast cells from the tibia and femur in different groups. Results: The ROS level and blast cells count were higher in disease control groups than in groups treated with varying amounts of B. persicum extract and the normal group. Moreover, there was an imbalance in hematological parameters in untreated and treated groups with a correlation between free radicals and plant extract administration. Conclusion: These findings may indicate a possible link between free radicals and hematotoxicity and blast cells, while depicting a potential therapeutic role for B. persicum against ROS-induced hematotoxicity.

Mild, Selective Oxidation of Aromatic Alcohols Using <font>β</font>-Cyclodextrin-Functionalized Glass Microparticles: Characterization, Stability, and Application

Tahir, Muhammad Nazir,Qamar, Riaz-ul,Adnan, Ahmad,Ghaffar, Abdul,Jun, Bong-Hyun,Yu, Jae-Hyuk,Jung, Seunho Informa UK (TaylorFrancis) 2014 Synthetic communications Vol.44 No.5

Efficient excitation and amplification of the surface plasmons

Tahir Iqbal 한국물리학회 2018 Current Applied Physics Vol.18 No.11

One dimensional (1D) grating has been fabricated (using focused ion beam) on 50 nm gold (Au) film deposited on higher refractive index Gallium phosphate (GaP) substrate. The sub-wavelength periodic metal nano structuring enable to couple photon to couple with the surface plasmons (SPs) excited by them. These grating devices provide the efficient control on the SPs which propagate on the interface of noble metal and dielectric whose frequency is dependent on the bulk electron plasma frequency of the metal. For a fixed periodicity (Λ=700 nm) and slit width (w=100 nm) in the grating device, the efficiency of SPP excitation is about 40% compared to the transmission in the near-field. Efficient coupling of SPs with photon in dielectric provide field localisation on sub-wavelength scale which is needed in Heat Assisted Magnetic recording (HAMR) systems. The GaP is also used to emulate Vertical Cavity Surface emitting laser (VCSEL) in order to provide cheaper alternative of light source being used in HAMR technology. In order to understand the underlying physics, far-and near-field results has been compared with the modelling results which are obtained using COMSOL RF module. Apart from this, grating devices of smaller periodicity (Λ=280 nm) and slit width (w=22 nm) has been fabricated on GaP substrate which is photoluminescence material to observe amplified spontaneous emission of the SPs at wavelength of 805 nm when the grating device was excited with 532 nm laser light. This observation is unique and can have direct application in light emitting diodes (LEDs).

Limiting the sway on multi-storey un-braced steel frames bending on weak axis with partial strength connections

Tahir, Mahmood Md.,Ngian, Poi Shek Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.38 No.6

This paper investigates the design using wind-moment method for semi-rigid un-braced steel frames bending on weak axis. A limiting sway method has been proposed to reduce the frame sway. Allowance for steel section optimization between moment of inertia on minor axis column and major axis beam was used in conjunction with slope-deflection analysis to derive equations for optimum design in the proposed method. A series of un-braced steel frames comprised of two, four, and six bays ranging in height of two and four storey were studied on minor axis framing. The frames were designed for minimum gravity load in conjunction with maximum wind load and vice-versa. The accuracy of the design equation was found to be in good agreement with linear elastic computer analysis up to second order analysis. The study concluded that the adoption of wind-moment method and the proposed limiting sway method for semi-rigid steel frame bending on weak axis should be restricted to low-rise frames not more than four storey.

Antioxidant potential of a soft cheese (paneer) supplemented with the extracts of date (Phoenix dactylifera L.) cultivars and its whey

Tahir Mahmood Qureshi,Aniqa Amjad,Muhammad Nadeem,Mian Anjum Murtaza,Masooma Munir 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.10

Objective: The present study was conducted to evaluate the antioxidant potential of paneer, a soft cheese supplemented with various water soluble date extracts during storage. Further, the whey obtained from all the paneer samples was also investigated for its antioxidant potential. Methods: The date cultivars were evaluated for their physico-chemical characteristics and date extracts were assessed for their antioxidant potential. Physico-chemical evaluation, microbiological quality and further antioxidant potential of the prepared paneer were carried out during storage period (0 to 8 days, 5°C). Results: All the date extracts were found to have considerable antioxidant activity due to presence of total phenolics and flavonoids. Owing to the presence of phenolics and flavoinds in date extracts, supplemented paneer showed higher trolox equivalent antioxidant capacity, reducing power and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity than control paneer. Paneer supplemented with Rabi extracts had the highest total phenolics (190.7 μg gallic acid equivalent/g paneer), DPPH radical scavenging activity (928.1 μmol equivalent of Trolx/g paneer) and trolox equivalent antioxidant capacity (9.2 μmol equivalent of Trolx/g paneer). The whey obtained from control paneer showed lower values of total phenolics, total flavonoids, DPPH, trolox equivalent antioxidant capacity and reducing power as compared to the values of whey obtained from paneer supplemented with date extracts. Conclusion: Paneer supplemented with date extracts and its whey may offer potent antioxidant activity.

Characterization of a Begomovirus-Betasatellite Complex, Producing Defective Molecules in Spinach (Spinacia oleracea L.), a New Host for Begomovirus and Betasatellite Complex in Pakistan

Tahir, Muhammad Nouman,Hameed, Amir,Amin, Imran,Mansoor, Shahid The Korean Society of Plant Pathology 2017 Plant Pathology Journal Vol.33 No.5

Spinach is a vegetable crop which is widely grown over a large area especially in Punjab province of Pakistan. Leaf curling and enations on spinach plant collected shown to be associated with the begomovirus Pedilanthus leaf curl virus (PeLCV) and Shahdadpur strain of Cotton leaf curl Multan betasatellite ($CLCuMB^{Sha}$). Defective molecules of half and quarter size derived from monopartite begomoviruses are usually generated by the deletion of virion-sense sequences. Characterization of defective molecules of PeLCV from spinach revealed that the molecules of half the size are derived from the deletion of complementary-sense genes while quarter size molecule appears to have evolved by further deletion. This is the first report of the begomovirus-betasatellite complex on spinach and unusual defective molecules derived from deletion of complementary-sense genes in Pakistan.