Pelajar pulang ke kampus dalam situasi Covid-19. Bersediakah kita

Pandemik Covid-19 telah memberi kesan kepada seluruh pelosok dunia dari aspek ekonomi, pendidikan, sosial, budaya, gaya hidup, dan kesihatan mental. Pada 15 September 2021 sahaja, Malaysia telah mencatatkan jumlah kes aktif Covid-19 sebanyak 225,590. Langkah pencegahan seperti Perintah Kawalan Pergerakan (PKP) dan penjarakan sosial telah memberi impak yang besar kepada sistem pendidikan negara. Universiti-universiti dan kolej-kolej terpaksa menggantung operasi kelas fizikal dan beralih kepada pengajaran dan pembelajaran dalam talian, manakala kebanyakan pekerja dan staf terpaksa bekerja dari rumah

Oxi-P GUI: A Graphical User Interface (GUI) for wastewater treatment process in oxidation pond

The wastewater treatment process is aimed to reduce pollution to the appropriate level. An oxidation pond system can treat contaminants in wastewater. Oxidation ponds are use sunlight, bacteria, and algae to treat wastewater. This study developed an improved mathematical model and a graphical user interface (GUI), called oxi-P GUI to predict the wastewater treatment process in an oxidation pond. The correlation between dissolved oxygen (DO), chemical oxygen demand (COD), coliform bacteria, as well as concentrations of phototrophic bacteria (PSB) were examined. In MATLAB software, a revised model consisting of ordinary differential equations (ODEs) set of integrating the Monod equation was numerically solved utilising the fourth order Runge-Kutta method. The current model's root mean square error (RMSE) values were compared to the suggested model's RMSE values for model validation. The model offered a more accurate estimate than the existing model of changes in the amount of concentration in oxidation pond, which was necessary to produce acceptable water quality. A wastewater management personnel may use GUI to track water quality and determine the most effective wastewater treatment mechanism. Additionally, this user-friendly GUI will give a better understanding about the treatment process, especially to people with less programming skills

A modified predictive model for colour changes in French fries during frying

During frying, heat and mass transfer phenomena happen and cause the physiochemical changes that affect the colour of french fries. Moisture content, oil content, and colour are important quality parameters in frying french fries, while temperature, frying time, and sample thickness will affect the french fries. In this study, we developed a modified mathematical model for colour changes of French fries during frying. The colour changes were formulated using a first-order ordinary differential equation that was solved using the 4th order Runge-Kutta method in the MATLAB software. The formulation for rate constant was modified using the Arrhenius equation and the sum squared error (SSE) of the proposed model was compared with the SSE of existing models. The colour was evaluated based on two parameters which are oil temperature (150°C, 170°C, 190°C) during frying and sample thickness (5 mm,10 mm, 15 mm) of french fries. The results showed that incorporating the factor of moisture into the model provides a better prediction of lightness and yellowness of french fries during frying. Overall, we conclude that moisture plays a significant role in the colour changing of french fries

Simulation of COVID-19 outbreaks via graphical user interface (GUI)

Background: This research aimed to model the outbreak of COVID-19 in Malaysia and develop a GUI-based model. Design and methods: The model is an improvement of the susceptible, infected, recovery, and death (SIRD) compartmental model. The epidemiological parameters of the infection, recovery, and death rates were formulated as time dependent piecewise functions by incorporating the control measures of lockdown, social distancing, quarantine, lockdown lifting time and the percentage of people who abide by the rules. An improved SIRD model was solved via the 4th order Runge-Kutta (RK4) method and 14 unknown parameters were estimated by using Nelder- Mead algorithm and pattern-search technique. The publicly available data for COVID-19 outbreak in Malaysia was used to validate the performance of the model. The GUI-based SIRD model was developed to simulate the number of active cases of COVID-19 over time by considering movement control order (MCO) lifted date and the percentage of people who abide the rules. Results: The simulator showed that the improved SIRD model adequately fitted Malaysia COVID-19 data indicated by low values of root mean square error (RMSE) as compared to other existing models. The higher the percentage of people following the SOP, the lower the spread of disease. Another key point is that the later the lifting time after the lockdown, the lower the spread of disease. Conclusions: These findings highlight the importance of the society to obey the intervention measures in preventing the spread of the COVID-19 disease

Mathematical analysis for a system of nonlinear ordinary differential equations related to ethanol production

The fermentation process is a crucial stage in transforming substrate to ethanol. Ethanol is obtained by fermenting the substrate using microbial such as yeasts or bacteria. This process can be explained in a system of nonlinear Ordinary Differential Equations (ODEs) mathematical model. The broad understanding of the model can improve the prediction of ethanol production yield. In this paper, the stability analysis is done to investigate the stability of the proposed model and followed by the investigation of its parameter behaviour towards the model

Mathematical Modelling for Predicting the Performance of Photovoltaic Modul

The demand for photovoltaic (PV) system is growing rapidly driven by technological development and awareness of green environment. A photovoltaic system converts the energy of light into electricity without emission of harmful by-product. A complete PV system consists of a solar panel (which combination of few solar cells), Pulse Width Modular (PWM) and a battery. Eight photovoltaic parameters are used to characterized the quality and efficiency of a PV module i.e (i) short circuit current (ISC), (ii) open circuit voltage (VOC), (iii) Theoretical Power (PT), (iv) maximum power (PMAX), (v) voltage at PMAX (VMPP) , (vi) current at PMAX (IMPP), (vii) fill factor (FF) and (viii) efficiency (). The PV parameters of laboratory scale solar cell could be determined based on current-voltage (I-V) and power-voltage (P-V) curves which could be plotted using a combination of solar simulator and a potentiostat instruments. Two additional PV parameters i.e (i) reverse saturation current of diode (IRC) and (ii) photocurrent (IPV) have been studied intensively as input of mathematical models to simulate and determine the quality and efficiency of solar cells. However, reproduceable results and robust mathematical models are yet to be established. A mathematical model employing the IRC, IPV and diode ideality factor (a) – which received lack of focus by previous researchers; is proposed. We have validated the mathematical model by comparing the calculation I-V and P-V curves results with the specifications established by the manufacturer. We have conducted three studies based on different specification of silicon based solar module i.e (i) 300W, (ii) 265W and (iii) 250W to obtain temperature distributions and average solar irradiance at selected locations. Through a comparative analysis, the theoretical calculation results and the manufacturers’ specifications are in good agreement

Mathematical modelling for predicting the performance of photovoltaic module

The demand for photovoltaic (PV) system is growing rapidly driven by technological development and awareness of green environment. A photovoltaic system converts the energy of light into electricity without emission of harmful by-product. A complete PV system consists of a solar panel (which combination of few solar cells), Pulse Width Modular (PWM) and a battery. Eight photovoltaic parameters are used to characterized the quality and efficiency of a PV module i.e (i) short circuit current (ISC), (ii) open circuit voltage (VOC), (iii) Theoretical Power (PT), (iv) maximum power (PMAX), (v) voltage at PMAX (VMPP) , (vi) current at PMAX (IMPP), (vii) fill factor (FF) and (viii) efficiency (). The PV parameters of laboratory scale solar cell could be determined based on current-voltage (I-V) and power voltage (P-V) curves which could be plotted using a combination of solar simulator and a potentiostat instruments. Two additional PV parameters i.e (i) reverse saturation current of diode (IRC) and (ii) photocurrent (IPV) have been studied intensively as input of mathematical models to simulate and determine the quality and efficiency of solar cells. However, reproduceable results and robust mathematical models are yet to be established. A mathematical model employing the IRC, IPV and diode ideality factor (a) – which received lack of focus by previous researchers; is proposed. We have validated the mathematical model by comparing the calculation I-V and P-V curves results with the specifications established by the manufacturer. We have conducted three studies based on different specification of silicon based solar module i.e (i) 300W, (ii) 265W and (iii) 250W to obtain temperature distributions and average solar irradiance at selected locations. Through a comparative analysis, the theoretical calculation results and the manufacturers’ specifications are in good agreemen

Mathematical Formulae

Mathematical Formulae intends to provide students, scientists, engineers, and researchers with a readily available reference to the mathematical formulae needed during their studies or work situation. It is a handy book that one must have on the bookshelf. The text is divided, for ease of reference, into ten main chapters embracing algebra, trigonometry, limit, differentiation and integration, vector calculus, coordinate geometry, differential equations, numerical methods, discrete mathematics, and financial mathematics. Essential theory, formulae, definitions and laws are clearly stated in this boo

Campus reopening during the COVID-19: ODE-SIRD model

The education system went through major transformations and was adversely impacted when all schools and Higher Education Institutions (HEIs) were forced entirely to close due to the country dealing with the coronavirus disease 2019 (Covid-19) pandemic. This is now a phenomenon that significantly concerns people all over the world. Upon campus reopening, the outbreak will occur within the campus community, and the students might get infected. This paper proposed two types of mathematical models based on the Ordinary Differential EquationSusceptible-Infected-Recovered-Dead (ODE-SIRD) framework to study the impact of campus reopening on the dynamic of the outbreak, which are: i) constant epidemiological parameters and ii) time-dependent epidemiological parameters. Other than that, a sensitivity analysis of parameters is carried out to determine the relative influence of the model parameters on disease transmission. We applied this model to observe Covid-19 cases in the selected higher institute in Malaysia. In comparison, the results indicate that the models with timedependent rates better predict the progression of the Covid-19 outbreak. Hence, from this finding, the time-dependent function of epidemiological parameters should be included in a model for the Covid-19 outbreak related to campus reopening. The effect of lockdown time on the number of active cases is also investigated. In conclusion, the results help and improve in making a reasonable prediction about the infection's evolution of the outbreak

Mathematical Formulae 2.0

Mathematical Formulae intends to provide students, scientists, engineers, and researchers with a readily available reference to the mathematical formulae needed during their studies or work situation. It is a handy book that one must have on the bookshelf. The text is divided, for ease of reference, into ten main chapters embracing algebra, trigonometry, limit, differentiation and integration, vector calculus, coordinate geometry, differential equations, numerical methods, discrete mathematics, and financial mathematics. Essential theory, formulae, definitions and laws are clearly stated in this boo