Stability and Control Assessment of an Aerial Target Drone Based on a Scale Model of A-4 Skyhawk Jet Fighter

A-4 Skyhawk is a jetfighter aircraft which was bought by our Royal Malaysia Air Force (RMAF) back in the year 1980s. The study is to evaluate the stability and control aspects of the design of A-4 Skyhawk as a target drone with a scale of one third. The condition of the studies involve the longitudinal and lateral controls of the open loop derivatives at the sea level and 10,000 feet altitude, for ranges of Mach number of 0.2, 0.3, 0.4, 0.5 and 0.6. Hence, the closed loop derivatives shall be designed to cater for the unsatisfactory parameters. With the usage of stability software such as the United State Air Force Stability and Control DATCOM (USAF DATCOM), analysis softwares such as MATLAB and CATIA, the method of design concept shall be more viable in order to produce a stable design. The USAF DATCOM software is used to generate the static and dynamic aerodynamic derivatives of the given aircraft. MATLAB is mathematical software used to perform high speed and massive calculations. MATLAB is used to obtain the transfer function of the aircraft equation of motion, to perform stability analysis and to plot the stability related graphs. The CATIA software is used to develop the full scale and scale size model of the A-4 Skyhawk jetfighter. From this software the scale model dimension, estimated weight and second moment of inertia is obtained. Thus, combination of all the software and calculation, the output of the study shall be able to meet the objectives of the study. It was found that, for the open loop derivatives of the longitudinal motion, the flying qualities for both short period and phugoid modes felt in the Level 2 category. As for the lateral motion, the flying qualities of the Dutch roll, spiral and roll modes felt in the Level 1 category as described by the Cooper-Harper scale. However, the critical scenario for the longitudinal and lateral for both the sea level and 10,000 feet altitude occurred at the speed of Mach number 0.2, where it had the most oscillatory conditions and the least settle for steady state condition. This may due to the less effectiveness of the delta wing at low speed flying condition

THE STRUCTURAL PROPERTIES OF GRAPHENE OXIDE AND REDUCED GRAPHENE OXIDE GROWN ON STAINLESS STEEL SUBSTRATE

In this paper, the structural properties of graphene oxide (GO) and reduced graphene oxide (rGO) based on custom-made, sodium 1,4-bis (neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14) surfactant were investigated. GO was synthesized by electrochemical exfoliation and chemical reduction process utilizing hydrazine hydrate was further done to produce rGO. The obtained GO and rGO solution were then transferred to stainless steel substrate by spraying deposition method. Based on several characterizations, the fabricated film has potential to be used as electrode for water treatment application. Key words: Graphene Oxide, Reduced Graphene Oxide, Stainless Steel, Electrochemical, Spraying. ABSTRAK Dalam artikel ini diteliti sifat struktural dari oksida grafin (GO) dan oksida grafin yang direduksi (rGO) menggunakan surfaktan sodium 1,4-bis (neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14) yang dibuat khusus. GO disintesis menggunakan eksfoliasi elektrokimia dan proses reduksi kimiawi menggunakan hidrazin hidrat untuk menghasilkan rGO. Larutan GO dan rGO yang dihasilkan kemudian ditransfer ke substrat stainless steel degan metode deposisi penyemprotan. Berdasarkan beberapa karakterisasi, film yang difabrikasi memiliki potensi untuk digunakan sebagai elektroda untuk aplikasi pengolahan air. Kata kunci: Oksida grafin, oksida grafin direduksi, stainless steel, elektrokimia, penyemprota

Knowledge of Hepatitis B among undergraduate students in Universiti Teknologi MARA (UiTM) Selangor, Puncak Alam Campus / Nurul Atika Abu Bakar, Wan Nur Azrina Wan Mohd Zaid and Nur 'Aqilah Md Salleh

Background: Hepatitis is an inflammation of the liver, most generally brought on by a viral infection. In Malaysia, as indicated by Ministry of Health, there have been 5% of Malaysians infected with hepatitis B. Inadequate knowledge regarding Hepatitis B Virus (HBV) may put our teenagers at risk of the infection. Objective: This study was carried out to evaluate the knowledge of Hepatitis B among undergraduate students at Universiti Teknologi MARA (UiTM) Selangor, Puncak Alam Campus. Methods: A cross sectional study design was conducted using a survey questionnaire and was distributed to 367 undergraduate students at Universiti Teknologi MARA (UiTM) Selangor, Puncak Alam Campus. Result: The findings show that there is no statistically difference between knowledge of hepatitis B with demographic characteristics which are age, gender, ethnicity, faculty of study and years of study (p>0.05). About 66.3% of the participants do not know about Hepatitis B. Conclusion: As a conclusion, knowledge about Hepatitis B among undergraduate students was poor. There is no significance difference between knowledge of Hepatitis B and selected socio demographic data such as gender, age, faculty, and years of education

Characterization and In Vitro evaluation of a novel coated nanocomposite porous 3D scaffold for bone repair

The aim of this study is to tissue engineer a 3D scaffold that can be used for load bearing segmental bone defects (SBDs) repair. Three different scaffolds were fabricated using cockle shell-derived CaCO3 aragonite nanoparticles (CCAN), gelatin, dextran and dextrin with coated framework via Freeze-Drying Method (FDM) labeled as 5211, 5211GTA+Alginate, 5211PLA. Scaffolds were assessed using Scanning Electron Microscopy (SEM). The cytocompatibility of the organized scaffolds was assessed using cells multiplication and alkaline phosphatase (ALP) concentration via In Vitro cell culture using human Fetal OsteoBlast cells line (hFOB). The results showed a substantial difference in ALP concentrations between the cultures of different scaffolds leachable medium during the study period. The biological evaluation also showed that three scaffolds did enhanced the osteoblast proliferation rate and improved the osteoblast function as demonstrated by the significant increase in ALP concentration. Engineering analyses showed that scaffolds possessed 3D interconnected homogenous porous structure with a porosity ranging 6%-49%, pore sizes ranging 8-345 µm, mechanical strength ranging 20-65 MPa, young’s modulus ranging 166-296 MPa and enzymatic degradation rate between 16%-38% within 2-10 weeks. The in vitro evaluation revealed that the scaffold 5211, 5211GTA+Alginate and 5211PLA fulfill all the main requirements to be considered as an ideal bone replacement

A Comparison of Assays for Accurate Copy Number Measurement of the Low-Affinity Fc Gamma Receptor Genes FCGR3A and FCGR3B

The FCGR3 locus encoding the low affinity activating receptor FcγRIII, plays a vital role in immunity triggered by cellular effector and regulatory functions. Copy number of the genes FCGR3A and FCGR3B has previously been reported to affect susceptibility to several autoimmune diseases and chronic inflammatory conditions. However, such genetic association studies often yield inconsistent results; hence require assays that are robust with low error rate. We investigated the accuracy and efficiency in estimating FCGR3 CNV by comparing Sequenom MassARRAY and paralogue ratio test-restriction enzyme digest variant ratio (RT-REDVR). In addition, since many genetic association studies of FCGR3B CNV were carried out using real-time quantitative PCR, we have also included the evaluation of that method’s performance in estimating the multi-allelic CNV of FCGR3B. The qPCR assay exhibited a considerably broader distribution of signal intensity, potentially introducing error in estimation of copy number and higher false positive rates. Both Sequenom and PRT-REDVR showed lesser systematic bias, but Sequenom skewed towards copy number normal (CN = 2). The discrepancy between Sequenom and PRT-REDVR might be attributed either to batch effects noise in individual measurements. Our study suggests that PRT-REDVR is more robust and accurate in genotyping the CNV of FCGR3, but highlights the needs of multiple independent assays for extensive validation when performing a genetic association study with multi-allelic CNVs

Technical, Safety and Economical Aspects of Considering Repair to Aircraft Structures

The design of repair for airframe structural damage requires a working knowledge of the material properties and it’s applications, the nature of structural loading and deformation and principles of joint design. The structures engineers who have those knowledge will be able to rectify the damaged aircraft structures with adequate and timely repairs. The airplane Manufacturer Structures Engineer utilises recognised engineering principles, approved material allowable and state of the art fatigue design technology to produce an airplane capable of assuring a high level of fleet reliability while the Airline or MRO Structures engineer is limited by the parameters of the local structure in the damaged area and must design repairs to restore the structural integrity with limited resources under stringent maintenance deadlines and often during unscheduled downtime. Therefore, structurally safe and economical operations of civil transport airplanes are a highly complex team effort which requires early and on-going operation between the Airline and Manufacturer Structures Engineers. This paper outlines the demanding tasks experienced by the Airline Structures Engineer and provides an overview the challenging tasks when considering repair to aircraft structures in the aspects of technical, safety and cost effectiveness

Fabrication and characterization of polymer thermo-optic switch based on MMI coupler

The 2×2 polymer thermo-optic switch based on MMI coupler is realized. This device is fabricated using standard fabrication techniques such as coating, photolithography, and dry etching. A crosstalk level of -36.2 dB is achieved at cross and bar states. A power consumption of 1.85 mW is applied to change the state of the switch from the cross to the bar state. A switching time of less than 0.7 ms is traced to change a state of the realized switch