Conceptual design of a small non-rigid airship with particular attention to its static and dynamic stability

Small size airships are traditionally designed and built based on experience rather than scientific approaches. Hence, its design approach has only been discussed in a very limited number of literatures. Thus, with these challenges at hand, a conceptual design study of airship in Malaysia was done to identify and explore the basic technology of airship design. This study focused on the conceptual design, determination of basic specifications and preliminary design of small size non-rigid airship for monitoring missions in Malaysia. The preliminary design focused on static stability, dynamic stability and development of a virtual simulator. The mathematical model of the designed airship for dynamic stability was rederived based on literatures and is then programmed to Graphical User Interface (GUI) with the aid of Matlab software. The airship was designed to fulfill the design specification suitable for monitoring with maximum speed of 40 km/h, cruising speed of20 km/h, operating altitude of 120 m and able to carry payload of at least of 6 kg. The dimension of 10 m length with maximum diameter of2.3 m was chosen with a pair of 0.25 hp engines to accomplish the desired specification. The designed airship was statically stable with trimmed angle of attack of approximately 0.18 degree. Through mathematical model of airship dynamics, following a detailed procedure including stability considerations, the airship had been analyzed and found to be dynamically stable with low control power and the time taken for the longitudinal response of elevator and vectored thrust to become stable was in the order of approximately 80 seconds while the lateral response of rudder becomes stable in approximately 30 seconds. The result of this study concluded that the designed airship fulfilled the design specification for monitoring mission and the designed airship was statically and dynamically stable during cruising speed. The virtual simulator also effectively provides a better understanding of the response of the designed airship through visualization

The development of welding fumes health risk assessment tool for automotive component related industries

The environmental quality index had been applied and used widely for water and ambient air quality. However, indices for industrial indoor air pollutants are relatively novel and limited. Currently, the welding fume exposure risk assessments are largely focused on a single welding fume constituent approach because the regulatory standard for compliance only caters for a single constituent. However, in reality, welders are simultaneously exposed to multiple welding fume constituents at once. To fulfill this gap, welding fumes health index was developed by assigning doses rating and health risk rating to the multiple constituent of welding fumes and aggregated into index values. In the initial stage of this study, the type of health risks included in the index (sensitizer, respiratory toxins, target organ toxins, and carcinogenicity) and the related technical characteristics were determined by using quality function deployment approach. Personal samplings of welding fumes were conducted in Plant 1 and 2 to assess the concentration of metal constituents during the investigation of case studies along with a series of pulmonary function tests and questionnaire on persistent symptoms. Index values were derived from the aggregation analysis of metal constituent constituents while significant persistent symptoms and pulmonary functions were recognized through statistical analysis. The proposed index was then applied to a selected welding industry for verification purposes (Plant 3). The results of the study showed that the index value was directly proportional with the percentage decrease of the welder’s pulmonary functions in all investigated plants and the significant persistent symptoms (Plant 1: mean index value=1.42, FVC=84.09%, FEV1=88.51%, PEF= 68.58%, significant persistent symptom: sore or dry throat; Plant 2: mean index value=1.40, FVC=87.86%, FEV1=91.14%, PEF=71.68%, significant persistent symptom: none ;Plant 3: mean index value=1.30, FVC=89.65%, FEV1=91.96%, PEF= 80.57%, significant persistent symptom: none). The developed welding fumes health index showed its promising ability to rank welding workplace that associates well with persistent symptoms and pulmonary functions of the investigated welders

Development of UTHM’s Airship Virtual Simulator

Airship virtual simulator was developed by programming the solution of the airship equations of motion to Matlab GUI. This paper shows a case study done by applying the physical data of a designed airship called ‘UTHM’s Airship’ in the airship equations of motion for development of airship virtual simulator. In this study, the approximate and calculated stability modes of the designed airship were compared for validation purposes. The virtual simulator operates by selecting the desired control angle of elevator, rudder or vectored thrust as input and the response outputs are shown in motion of pitch, yaw or roll angle through a moving airship figure in the simulator. At the end of this paper, the virtual simulator had successfully helped interprets the response of the designed airship into an interesting and easy to understand visualization

Development of UTHM's Airship Virtual Simulator

Airship virtual simulator was developed by programming the solution of the airship equations of motion to Matlab GUI. This paper shows a case study done by applying the physical data of a designed airship called ‘UTHM’s Airship’ in the airship equations of motion for development of airship virtual simulator. In this study, the approximate and calculated stability modes of the designed airship were compared for validation purposes. The virtual simulator operates by selecting the desired control angle of elevator, rudder or vectored thrust as input and the response outputs are shown in motion of pitch, yaw or roll angle through a moving airship figure in the simulator. At the end of this paper, the virtual simulator had successfully helped interprets the response of the designed airship into an interesting and easy to understand visualization

Thin film flow of non-newtonian third grade fluid down an inclined plane by variation of parameter method

In this study, a non-Newtonian third-grade fluid flow down an inclined parallel plate held horizontally against each other are investigated. As the nonlinear differential equation which governs the flow model can be obtained by using the conversation of laws, the Variation of Parameters Method (VPM) is then applied to solve the aforementioned differential equation. The proposed VPM is applied without any discretization, perturbation, transformation or restrictive assumptions and is free from round off errors and calculation. Analytical solution solved by Runge-Kutta numerical solution and the VPM show excellent agreement. Effects of flow parameters β and m on the velocity field are demonstrated graphically with comprehensive discussions. Numerical results reveal the complete reliability of the proposed VPM

Evaluation of Respiratory Symptoms, Spirometric Lung Patterns and Metal Fume Concentrations among Welders in Indoor Air-Conditioned Building at Malaysia

Welding is one of the fundamental processes for metal joining in automotive industries and there is an increasing concern over occupational lung disease among welder due to exposure towards welding fumes. A lung disease questionnaire (ATS-DLD-78) was used to record the presence of respiratory symptoms among welders and in assessing lung function assessment, FEV1, FVC and FEV1/FVC are considered for identifying the lung condition; normal, obstructive or restrictive. The data were tabulated and subjected to logistic and multivariate analyses. Meanwhile, in order to trace metal in welders’ body, this study utilized a non-invasive approach of toenail as a biomarker. Lung functions decrement was established in linear regression for FEV1 and FEV1/FVC respectively although not statistically significant. Analysis conducted revealed the presence of the following trace elements concentration in ascending sequence: As < Al < Cu < Mn < Cr < Ni < Co < Fe (in the toenail) and Co < Al < Cu < Ni < As < Cr < Fe < Mn (in the cassette), respectively. The results validated the postulation that toenail metals composition shared a similar route of exposure with an anthropogenic source of activity. It is suggested a longer follow-up study is required to assess individual effects on lung function systems and the incidence of respiratory diseases among welders and this study indicates that toenail is a reliable biomarker of metal-workplace pollution and suitable for acquiring chronological information of welding fumes exposure

A short review on biodiesel production and costing

Biodiesel has been introduced to reduce the dependency on fossil fuel. It is derived from vegetable oil, alcohol with the presence of a catalyst. One of the most significant issues in biodiesel market is the selling price. This paper will review the research conducted on the production of biodiesel, including the equipment, raw materials and cost. These three elements are crucial to reduce the price and enable biodiesel to be a competitive alternative fuel in the market. This paper also discusses recent developments in production, market values and suggestions for improving the biodiesel process. The results presented in this review may facilitate improvements in biodiesel production and costing

Thermal comfort of indoor open spaces at university library in Malaysia

The issues of improving thermal comfort inside the building have become a global point of research interest attributed to the realization that people spend more than 90% of their time in the indoor environment. This study investigated the thermal comfort temperature range for indoor open spaces in second level of the Universiti Tun Hussein Onn Malaysia (UTHM) library. The study conducted through subjective measurement (thermal sensation questionnaire) and physical measurement (air temperature, relative humidity, air velocity, mean radiant temperature measurement). A total of 120 occupants completed the thermal sensation questionnaire of indoor open spaces for morning and afternoon sessions for six days. Physical measurements data were also collected at eight measurement sampling point across the indoor open space for six days. The linear regression analysis for air temperature with thermal sensation vote (TSV) and predicted mean vote (PMV) for both morning session and afternoon session shows a good fit of the regression model on the observed data. It shows 70% of the variation in the output variable of TSV and PMV can be explained by the input variables of air temperature. The thermal comfort temperature ranges for TSV of -0.5 to +0.5 were within the range of 24.17 ∸C to 25.01∸C for morning session and 23.63 ∸C to 24.20 ∸C for the afternoon air temperature. In addition, the thermal comfort temperature ranges for PMV of -0.5 to +0.5 were 24.03 ∸C to 25.15 ∸C for morning session and 23.70 ∸C to 24.47 ºC for the afternoon. By using linear regression equation, the relation between air temperature, PMV and TSV were obtained

Preliminary Reliability Study of Computerized Neurobehavioural Test Method

The recently developed Neurobehavioural Risk Assessment Evaluation System 1.0 (NeuRAES 1.0) tool aims to assess the neurobehavioural performance in Malaysia. Prior to utilize the advantage of the developed NeuRAES 1.0 tool effectively, it is vital to evaluate its reliability. The study aimed to conduct test and retest of NeuRAES 1.0 and assess the reliability of the NeuRAES 1.0 tool among university students in Universiti Tun Hussein Onn Malaysia (UTHM). With that regard, the reliability of the tool was examined among 40 healthy university students using a test–retest of four computerized tests that are, Benton Visual Retention, Symbol Memory, Trail Making, and Pursuit Aiming, with the test and retest held two weeks apart. The reliability was analyzed for all test measures using the Pearson product-moment correlation coefficient (r) and the intraclass correlation coefficient (ICC). A two-way mixed effect model was applied in this study to determine the ICCs and their 95% confidence intervals. The finding of all parameter measures in all four tests for standard scores were significantly similar, and the improvements of scores were also detected at retest for raw scores. The test–retest scores were found to have the ICC values ranging from low to adequate (0.269 to 0.655). The low ICCs were detected on Memory Symbol Test (r = 0.264, ICC = 0.269), Trail Making Test (Section A: r = 0.377, ICC = 0.383; Section B: r = 0.445, ICC = 0.452), Benton Visual Retention Test (r = 0.511, ICC = 0.517), and Pursuit Aiming Test (Test B: r = 0.567, ICC = 0.574). An adequate ICC was found on Pursuit Aiming Test (Test A: r = 0.649, ICC = 0.655). This demonstrating that the instrument still have not achieved a condition where, a measurement process is capable to produce stable and consistent scores when repeated over time except for Pursuit Aiming Test (Test A). In conclusion, the findings extend our understanding of score changes due to repeat testing. A further review on the test measures with low ICC needs to be considered. Therefore, further studies with larger samples and varied group of populations would be valuable

Two-level factorial design of the pre-processing activities of polyamide 12 powder in selective laser sintering three-dimensional printing process

Powder exposure during selective laser sintering (SLS) three-dimensional (3D) printing process is detrimental to the health of workers in the indoor workspace and those in surrounding areas. To date, there is a paucity of studies concerning the factors involved in the SLS 3D printing process that have a significant effect on the indoor air concentrations. Hence, in this study, two-level factorial design was conducted to identify the factors that have a significant effect on the indoor air concentrations (particulate matter with a diameter less than 2.5 and 10.0 μm (PM2.5 and PM10), ultrafine particles (UFP), and total volatile organic compounds (TVOC)) during pre - processing activities of the SLS 3D printing process. The exposure during handling of polyamide 12 (PA12) was simulated in a 24-m2 SLS 3D printing chamber. The following factors were investigated: (1) Factor A (air velocity (fan speed of the split air conditioner), (2) Factor B (refresh rate (the use of recycled PA12 powder), (3) Factor C (collecting powder from the mixing machine), (4) Factor D (transferring powder to the SLS 3D printing machine), and (5) Factor E (pouring powder into the feeder chamber). The sampling methods were conducted according to the Industry Code of Practice on Indoor Air Quality, Department of Occupational Safety and Health, Malaysia. Based on the analysis of variance results, Factor B was the most significant factor that contributed to the PM2.5, PM10, UFP, and TVOC concentrations during the pre-processing activities of the SLS 3D printing process. In conclusion, proper handling and the use of an automated vacuum conveying technology for the pre-processing activities will help prevent the spreading of gaseous and aerosol particles to other areas within vicinity of the SLS 3D printing process