Development of rotational pulse-echo ultrasonic propagation imaging system capable of inspecting cylindrical specimens

Hasan Ahmed,Young-Jun Lee,Jung-Ryul Lee 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.5

A rotational pulse-echo ultrasonic propagation imager that can inspect cylindrical specimens for material nondestructive evaluations is proposed herein. In this system, a laser-generated ultrasonic bulk wave is used for inspection, which enables a clear visualization of subsurface defects with a precise reproduction of the damage shape and size. The ultrasonic waves are generated by a Q-switched laser that impinges on the outer surface of the specimen walls. The generated waves travel through the walls and their echo is detected by a Laser Doppler Vibrometer (LDV) at the same point. To obtain the optimal Signal-to-Noise Ratio (SNR) of the measured signal, the LDV requires the sensed surface to be at a right angle to the laser beam and at a predefined constant standoff distance from the laser head. For flat specimens, these constraints can be easily satisfied by performing a raster scan using a dual-axis linear stage. However, this arrangement cannot be used for cylindrical specimens owing to their curved nature. To inspect the cylindrical specimens, a circular scan technology is newly proposed for pulse-echo laser ultrasound. A rotational stage is coupled with a single-axis linear stage to inspect the desired area of the specimen. This system arrangement ensures that the standoff distance and beam incidence angle are maintained while the cylindrical specimen is being inspected. This enables the inspection of a curved specimen while maintaining the optimal SNR. The measurement result is displayed in parallel with the on-going inspection. The inspection data used in scanning are mapped from rotational coordinates to linear coordinates for visualization and post-processing of results. A graphical user interface software is implemented in C++ using a QT framework and controls all the individual blocks of the system and implements the necessary image processing, scan calculations, data acquisition, signal processing and result visualization.

Development of scanning single port free space measurement setup for imaging reflection loss of microwave absorbing materials

Ahmed, Hasan,Hyun, Jongmin,Lee, Jung-Ryul Elsevier 2018 MEASUREMENT -LONDON- Vol.125 No.-

<P><B>Abstract</B></P> <P>This paper proposes a scanning free-space measurement (SFSM) setup for the evaluation of microwave absorption properties of microwave absorbing materials<B>.</B> The system comprises of a vector network analyzer (VNA), focused horn antennas attached to the VNA for transmitting/receiving microwave signals, a dual-axis automated translation stage for raster scanning of the specimen and a standard personal computer. A graphical user interface (GUI) running on the computer manages the configuration and synchronization of the VNA and the stage system, measurement reception from VNA and compilation of results for display to the user. The GUI is created in C++ using Qt framework and Qt Widgets for Technical applications. It is designed with a minimalistic approach to promote usability and adaptability.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A scanning measurement setup for measuring microwave reflection loss is proposed. </LI> <LI> The setup is suitable for characterization of microwave absorbing materials. </LI> <LI> The setup can perform characterization of a selected scan area of the material. </LI> <LI> The proposed setup supports automated scan in parallel with real time result update. </LI> <LI> It is useful for characteristic evaluation of stealth and radome structures. </LI> </UL> </P>

Increasing of Macrophage Migration Inhibitory Factor Expression in Human Patients Infected with Virulent Brucella in Iraq

( Hasan R. Khudhur ),( Abbas Ali Menshed ),( Ahmed Abbas Hasan ) 한국미생물생명공학회(구 한국산업미생물학회) 2020 한국미생물·생명공학회지 Vol.48 No.4

Brucellosis is a zoonotic disease caused by Brucella infections and humans usually contract this disease from close contact with infected animals or their products, usually via the ingestion of cheese or crude milk. Macrophage migration inhibitory factor (MIF) and Pro- and anti-inflammatory cytokines play an important role in susceptibility/resistance and the immunopathogenesis of Brucella infection. These cytokines are crucial factors in the initiation and progression of protective immunity against Brucella infection but the role of MIF has not been well studied in the human response to intracellular microbes. This study was designed to investigate the effect of MIF expression on Brucella susceptibility. A total of 85 positive rose Bengal tests and 24 samples from healthy individuals were collected for this study and subjected to polymerase chain reaction assays (PCR) of the bcsp31 diagnostic gene. MIF concentrations were evaluated using Enzyme-Linked immunosorbent assay (ELISA) and the results showed that 46 (54%) of the rose Bengal test samples were positive and 39 (46%) were negative for bcsp31 (p ≤ 0.05) and used as the gold standard for all of the comparisons in this study. The ELISA results indicate that the mean concentration of MIF was significantly higher in patients with positive rose Bengal tests when compared to the control groups and that its concentration increases with increasing age in both the patient and control groups (p ≤ 0.05).

GPS/INS Integration Based on Dynamic ANFIS Network

Ahmed Mudheher Hasan,Khairulmizam Samsudin,Abdul Rahman Ramli 보안공학연구지원센터 2012 International Journal of Control and Automation Vol.5 No.3

The geometrical design of membraneless micro fuel cells: Failure and success

Ahmed, Dewan Hasan,Park, Hong Beom,Lee, Kyung Heon,Sung, Hyung Jin John Wiley Sons, Ltd. 2010 International journal of energy research Vol.34 No.10

<P>A comprehensive numerical study of membraneless micro fuel cells with various geometries is carried out with the aim of reducing the mixing of the anode and cathode fluids and increasing their fuel utilization. Designs with blocks or obstacles in the main channel or a main channel with a wavy shape result in very little improvement in these properties or even in their deterioration. However, some designs with other types of channel cross-section exhibit much less mixing of the two fluids in the main channel. In particular, an octagonal cross-section is found to result in better performance. However, the difficulty of the micro fabrication of fuel cells with this design encourages us to test two other geometries for the cross-section: H-shaped and trident-shaped. The H-shaped cross-section exhibits much less mixing in the main channel and much higher fuel utilization. The fuel cell with a trident-shaped cross-section has two inlets for the anode and cathode fluids and a third inlet for the proton-conducting fluid, and is found to be the best design in that the anode and cathode fluids are more restricted to their respective electrodes (reaction surfaces). Further, in this design the reactants cover only 40% of the channel width, which is much less than in the other designs, and maximum fuel utilization is obtained. The failure and success cases will guide for future geometrical design of any micro fluidic devices where mixing and non-mixing issues are the major concerns. The present numerical results are validated by comparison with literature data. Copyright © 2009 John Wiley & Sons, Ltd.</P>

Chronological Development of the Corporate Governance Guidelines in Bangladesh : A Comparative Analysis between CGG-2012 and CGC-20181

Ahmed Rizvan HASAN,Shuvo HOWLADER 한국웰빙융합학회 2020 웰빙융합연구 Vol.3 No.3

In this study, the chronological development of the Corporate Governance Guidelines (CGG) and Corporate Governance Code (CGC) examined to identify how much the Code has evolved over time. A comparative analysis between the CGG-2012 and CGC-2018 has also been conducted in the study to outline the latest changes. The study is exploratory and literature review-based in nature. Contemporary literatures were analyzed along with comparison of the CGG-2012 and CGC-2018 issued by the Bangladesh Securities and Exchange Commission (BSEC). Data was collected from various secondary sources. The study points out that the BSEC has followed a six-year interval pattern in the further development and modification of the corporate governance codes in Bangladesh. Also, it has been found out that in terms of the number of conditions in the code, the CGC-2018 is about 75 percent enhanced than CGG-2012. Previously, CGG-2012 was enhanced by more than 150 percent over the first guideline in 2006. CGC-2018 has introduced some crucial governance issues that were not present in the code before but there remain some areas that are yet to be addressed in the best-practices recommendations

Single and Multi-Strain Probiotics Supplementation in Commercially Prominent Finfish Aquaculture: Review of the Current Knowledge

Sumon, Md Afsar Ahmed,Sumon, Tofael Ahmed,Hussain, Md. Ashraf,Lee, Su-Jeong,Jang, Won Je,Sharifuzzaman, S.M.,Brown, Christopher L.,Lee, Eun-Woo,Hasan, Md. Tawheed The Korean Society for Microbiology and Biotechnol 2022 Journal of microbiology and biotechnology Vol.32 No.6

The Nile tilapia Oreochromis niloticus, Atlantic salmon Salmo salar, rainbow trout Oncorhynchus mykiss, olive flounder Paralichthys olivaceus, common carp Cyprinus carpio, grass carp Ctenopharyngodon idella and rohu carp Labeo rohita are farmed commercially worldwide. Production of these important finfishes is rapidly expanding, and intensive culture practices can lead to stress in fish, often reducing resistance to infectious diseases. Antibiotics and other drugs are routinely used for the treatment of diseases and sometimes applied preventatively to combat microbial pathogens. This strategy is responsible for the emergence and spread of antimicrobial resistance, mass killing of environmental/beneficial bacteria, and residual effects in humans. As an alternative, the administration of probiotics has gained acceptance for disease control in aquaculture. Probiotics have been found to improve growth, feed utilization, immunological status, disease resistance, and to promote transcriptomic profiles and internal microbial balance of host organisms. The present review discusses the effects of single and multi-strain probiotics on growth, immunity, heamato-biochemical parameters, and disease resistance of the above-mentioned finfishes. The application and outcome of probiotics in the field or open pond system, gaps in existing knowledge, and issues worthy of further research are also highlighted.

Beam-Column Connections Behavior of Cold-Formed Steel Members: New Experimental Configuration

Ahmed Shamel Fahmy,Sherine Mostafa Swelem,Hadi Hasan Mussttaf 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.7

The main purpose of this paper is to study the structural behavior of cold-formed steel connections. Five specimens of cold–formed beam to column connections are studied. The beams are connected to the columns by using two different shapes of gusset plates and self-drilling screws. Experimental tests on these cold–formed connections are carried out to obtain their ultimate capacities. A numerical analysis is performed on the same tested specimens and the finite element model is verified. The ultimate loads obtained from the numerical analysis as well as the load–strain curves and buckling modes are compared with those obtained from the experimental tests and are found to be in good agreement. The finite element model well predicts the stress and deflection values, as well as the buckling modes of the specimens. Some recommendations are concluded to help researchers and designers choose the optimum type of beam to column connection.

New approach to calculate Weibull parameters and comparison of wind potential of five cities of Pakistan

Ahmed Ali Rajput,Muhammad Daniyal,Muhammad Mustaqeem Zahid,Hasan Nafees,Misha Shafi,Zaheer Uddin Techno-Press 2022 Advances in energy research Vol.8 No.2

Wind energy can be utilized for the generation of electricity, due to significant wind potential at different parts of the world, some countries have already been generating of electricity through wind. Pakistan is still well behind and has not yet made any appreciable effort for the same. The objective of this work was to add some new strategies to calculate Weibull parameters and assess wind energy potential. A new approach calculates Weibull parameters; we also developed an alternate formula to calculate shape parameters instead of the gamma function. We obtained k (shape parameter) and c (scale parameter) for two-parameter Weibull distribution using five statistical methods for five different cities in Pakistan. Maximum likelihood method, Modified Maximum likelihood Method, Method of Moment, Energy Pattern Method, Empirical Method, and have been to calculate and differentiate the values of (shape parameter) k and (scale parameter) c. The performance of these five methods is estimated using the Goodness-of-Fit Test, including root mean square error, mean absolute bias error, mean absolute percentage error, and chi-square error. The daily 10-minute average values of wind speed data (obtained from energydata.info) of different cities of Pakistan for the year 2016 are used to estimate the Weibull parameters. The study finds that Hyderabad city has the largest wind potential than Karachi, Quetta, Lahore, and Peshawar. Hyderabad and Karachi are two possible sites where wind turbines can produce reasonable electricity.

Antioxidant, antinociceptive activity and general toxicity study of Dendrophthoe falcata and isolation of quercitrin as the major component

Hasan, Md Shihab,Ahmed, Md Iqbal,Mondal, Sukla,Masud, Mohammad Methedi,Sadhu, Samir Kumar,Ishibashi, Masami,Uddin, Shaikh Jamal Kyung Hee Oriental Medicine Research Center 2006 Oriental pharmacy and experimental medicine Vol.6 No.4

Plants have been used in traditional medicinal system for centuries. Bangladeshi medicinal plants have received considerable attention from the researchers for evaluation of their bioactivity. As a part of our ongoing research of screening the Bangladeshi medicinal plants, the ethanolic extract of Dendrophthoe falcata have been chosen for the present study. The ethanolic extract of the leaves of the plant have been assessed for their antioxidant, antinociceptive, and general toxicity. The extract showed potent antioxidant activity ($IC_{50}5.1{\mu}g/ml$) using DPPH radical scavenging assay, which is comparable to the standard ascorbic acid ($IC_{50}4.6{\mu}g/ml$). The extract significantly and dose dependently inhibited the acetic acid induced writhing in mice (71.2%, P < 0.001 and 28.0%, P < 0.05 for 500 and 250 mg/kg body weight, respectively). A general toxicity was assessed by a simple and low cost assay using brine shrimp lethality as an indicator. The extract showed low level of toxicity ($LC_{50}100{\mu}g/ml$). Using different chromatographic techniques, quercitrin (quercetin 3-O-${\alpha}$-rhamnoside) was separated as the major component from the extract. The structure was elucidated by detailed 1D and 2D NMR and mass spectral analysis.