Latin American Applied Research - An international journal

Analytical approach to an electrically conducting micropolar fluid flow past a vertical porous plate

S.R. MISHRA — 2025-01-09

Free convective flow of steady laminar incompressible micropolar fluid past over a vertical stretching sheet has been studied. In addition to an electrically conducting fluid in the presence of porous medium, study of buoyant parameters, uniform heat source as well as the entire discussion of mass transfer Eq. is taken into consideration. Superimposing similarity transformation the complex PDEs are turned into nonlinear ODEs. The speciality of the present study is the solution procedure. The highly nonlinear differential Eq.s are more critical to handle analytically. However, a new analytical approach is used to solve these complex Eqs. Before employing perturbation we use a particular substitution which satisfies the prescribed boundary conditions. The influence of various pertinent parameters on the flow phenomena is displayed via graphs and for validation present result is compared with earlier published result in particular cases. Finally, the major outcomes are laid down as follows: cooling of the plate increases both the velocity profile however, heating decreases significantly. Copper is a good conductor of heat and used as a media for heat exchanger

Flow of Casson nanofluid with energy transfer and slip effects over an exponentially porous expanding surface and its dual solutions

Debasish Dey — 2025-01-09

The occurrence of dual solutions of the Casson nanofluid generated by an exponentially expanding surface located in an absorbent medium and second-order slip effects have been examined. In the transverse direction of the flow, a homogeneous magnetic field is taken into account. The model equations are modified using a suitable similarity transformation so that they may be computed using the bvp4c solver technique in MATLAB. The outcomes are presented graphically and in tabular form, along with some innovative flow variables. Two solutions have been identified using the stability analysis, one of which is both physically feasible and stable in nature. As a result of the investigation, it is clear that the fluid's ability to transmit heat is improved by the flow characteristics related to nanofluid. The considering fluid model is one of the best fluid models, as this model reduces the effects of shear stress at the surface during both first and second solutions and protecting the system from flow related damage. We performed a comparison to ensure the accuracy of our results and discovered a good match. The considering fluid model has significant applications in different physical fields such as heat exchangers, cooling of electronic devices and drug delivery in the human body etc. The flow behavior of Casson nanofluids over a stretching surface may lead to improved efficiency, reduced energy consumption and better product quality etc.

Computational exploration and flow control analysis of alumina – magnetite/water-based hybrid nanofluid over a permeable Riga plate under the impact of Soret-Dufour effects

Dhivya Mohanavel — 2025-01-09

The current study aims to analyze the behavior of a hybrid nanofluid, comprising of alumina and magnetite nanoparticles with base fluid as water, when it flows over a vertical permeable Riga-plate including the electromagnetohydrodynamic (EMHD) principles. The coupled governing equations are nonlinear and it has been simplified using appropriate non-dimensional parameters. A numerical analysis was then carried out utilizing the finite difference scheme, in particular Crank-Nicholson technique. This study primarily focuses on the significance of physical parameters such as magnetic field, permeability, volume fraction of nanoparticles, radiation, viscous dissipation, Soret-Dufour effect and chemical reaction which are analyzed through graphical illustrations. It has been observed that Soret and Dufour effects exert influence on the profiles of temperature and concentration. In addition, Viscous dissipation and radiation reinforces the temperature. The impact of chemical reaction retards the thickness of concentration boundary layer. The integration of nanoparticles with Riga-plate allows for better flow control and manipulation of heat transfer processes, makes it ideal for applications in the cooling process of electronics equipment, thermal management systems and energy production. Further, Response surface model (RSM) is demonstrated to analyze the sensitivity of permeable Riga plate with respect to various pertinent parameters. RSM explores more on the intricate interactions between the input variables and the response variables. It is also inferred that uplifting the value of magnetic parameter and the permeability parameter accelerates the wall shear stress. Graphical comparison made with previous studies for validating the results.

Influence of Dufour, Hall, and radiation absorption on MHD convective flow past an accelerated perpendicular sheet implanted with porous medium

Mridusmita Bormudoi — 2025-01-09

The action of Hall current, Dufour, radiation absorption on an MHD free convective flow passing through an accelerated perpendicular sheet implanted with porous media is explored in the current work. The flow governing equations introduced here are first converted to non-dimensional form by the use of some non-dimensional parameters. Then these equations are solved using the perturbation technique. The fluctuations in velocity, temperature, and concentration due to various parameters are depicted graphically. Some important findings are, the growth in the Dufour effect and Hall current, enhances the flow. Also, the rotating effect of fluid causes a restriction in the fluid flow which lowers the velocity of the fluid.

Insights into two-dimensional hydromagnetic flow in porous and non-porous media: Horizontal channel behaviour with COMSOL Multiphysics

Sahin Ahmed — 2025-01-09

The novelty of this study is highlighted by its innovative exploration of two-dimensional hydro-magnetic flow in a horizontal channel, focusing on the interaction between porous and non-porous media under magnetic influence. Utilizing the finite element method within COMSOL Multiphysics, the research aims to explore how fluid behaviour is affected by the presence of porous materials and magnetic fields. The simulations reveal significant insights, such as the op-timal stability achieved with a finely meshed grid and grid-independent analysis. This work not only en-hances the understanding of magnetohydrodynamic processes but also opens up new avenues for practical applications in fields where controlling fluid flow in porous media is critical. Notably, the study finds that higher Eckert numbers correlate with lower Nusselt numbers, while higher Prandtl numbers enhance heat transfer rates from high-temperature surfaces. Addi-tionally, the analysis shows that Forchheimer and magnetic drag forces reduce skin friction on the bot-tom surface, with distinct patterns observed on the top surface. The COMSOL Multiphysics approach ef-fectively captures flow and temperature dynamics, of-fering valuable implications for the design of heat ex-changer devices.

Numerical modelling and control of tumour mutation using piecewise fuzzy approach

Hami Tourajizadeh — 2025-01-09

Mutation dynamics of a cancer tumour is modelled here using numerical non-model-based approach of fuzzy and its metastasis is controlled using a closed loop controller. Cancer is the second cause of death in the world. Metastasis of the cancerous cells is the main source of its fatality and this phenomenon is extremely uncontrollable as a result of drug resistance. Drug resistance itself is the consequence of the mutation of the cancerous stem cells. Thus modelling the metastasis without considering the effect of mutation is not practically efficient. Since, the exact analytic modelling of mutation is usually impossible, here a numeric approach is proposed toward modelling the cancer mutation using the fuzzy method. As a result the number of the cancer cells and their related mutations are fuzzificated as the engaged states and their related performance subject to chemotherapy is predicted using the proposed fuzzy model. In order to increase the accuracy of the numerical modelling, the fuzzification process is modified using piecewise algorithm. Employing the mentioned numerical plant, it is possible to design and implement a closed loop controller using the feedback of the tumour, and consequently improve the schedule of chemotherapy in a way that the mutation and tumour growth would be blocked. State Vector Feedback Control (SVFC) is employed here to stabilize the mutation trigger and cancer development. Previous proposed analytic model of the studied cancer is employed here to provide the required data of fuzzy modelling instead of laboratory data and it is shown by the aid of MATLAB simulation that, using the proposed fuzzy model of cancer and mutation, the behaviour of the tumour can be predicted and its mutation and metastasis can be controlled successfully.

The effect of using wheat species on the quality and sensory properties of rice pudding

B. Yesilyurt Sagdic — 2025-01-09

It was aimed to determine some quality and sensory differences in the pudding by using wheat species instead of rice. For this, Einkorn wheat pudding, Iza wheat pudding, Emmer wheat pudding, Spelt wheat pudding and rice pudding (control) were prepared. It was determined that the dry matter, mineral matter and protein values of wheat pudding were higher than the control (P < 0.05). The use of different wheat varieties instead of rice in pudding production caused a decrease in the pH and L* values of the samples and an increase in the b* values. Iza wheat pudding was the highest dry matter, mineral matter, protein, water holding capacity, viscosity, firmness and adhesiveness values, followed by Einkorn wheat pudding. The highest structure-consistency, taste-smell and general acceptability values were determined in Siyez wheat pudding. It was concluded that Einkorn, Iza, Emmer and Spelt wheats can be used instead of rice in pudding production.

Improvement of nutritional quality of cookies by the formulation of premixes with alternative flours

Luz Marina Zapata — 2025-01-09

Developments formulations of traditional and gluten-free premixes for the preparation of cookies for school-age children that are low cost and that contribute to the nutritional requirements of the target population were studied. The proximal analysis and mineral profile of seventeen flours available in the local market was carried out. The raw materials of both premixes were selected by using linear programming. These premixes were 50 % cheaper than those available in the local market formulated only with wheat flour. Traditional cookies had each 100 g: 8.70 g protein, 13.02 g fiber, 4.13 g ash, 13.35 g fat, 55.80 g carbohydrate, 2.95 mg iron, 1.60 mg zinc, 103.22 mg calcium, 83.70 mg magnesium and 506.30 mg potassium. Gluten-free-cookies had each 100 g: 9.59 g protein, 13.99 g fiber, 1.50 g ash, 4.12 g fat, 55.79 g carbohydrate, 3.19 mg iron, 1.35 mg zinc, 94.62 mg calcium, 60.33 mg magnesium and 461.77 mg potassium. Results show that the premixes and cookies obtained constitute an adequate source of nutrients for school-age children.

Physico-mechanical properties of briquettes produced from woody biomass

Thomas Aghogho Orhadahwe — 2025-01-09

This study investigates the densification of sawdust from a mahogany tree (Khaya ivorensis) into briquettes for energy applications. The researchers used starch as a binder and four blends of sawdust and starch were prepared with varying proportions of the starch (60 - 75 g) while the mass of sawdust was constant at 60 g. The results showed that the 70 g starch binder briquette had the highest dry density (0.77 g/cm3) and water resistance (33.36%), while the 60 g binder briquette had the highest impact resistance index (250) and drop-to-fracture (15). The 65 g starch binder briquette had the highest compressive strength (519.7 kPa). The dry density and water resistance of briquettes increase with the increase in binder content, while impact resistance decreases. The briquettes can withstand adverse transportation and storage conditions. This research highlights the potential of woody biomass briquettes for energy applications.

Formulation and production of trans acid-free hard stock margarine using interesterification

Hülya Güçlü — 2025-01-09

In this study various blends were prepared from different vegetable sources in order to determine the proper fat ratio for preparing fat phases of the trans-free margarines. The selected fats were included palm oil (PO), fully hydrogenated soybean oil (FH), and palm oil stearin (POS) fraction and the liquid oils were included sunflower oil (SF) and cotton oil (C). The blended oils were interesterified after blending in the ratios according to the proposed experimental design. The blends and interesterified blends of these two groups of fats and oils were evaluated by testing the slip melting point (SMP) and solid fat content (SFC). The data obtained from the SFC values for the blends and model fats at different temperatures were used to determine their usability in different types of margarine. It was concluded that hydrogenated soybean oil was not suitable for hard stock margarine due to its high SFC and slip melting point and low essential fatty acid (FA) content. However, some trans free soft and stock margarines could be prepared from the blends of FH, PO and POS. Finally, it was concluded that natural solid vegetable oils such as PO and POS fractions can be mixed with cotton and sunflower oils in different proportions and interesterified could be used for the production of trans acid-free different margarines.

Metal soaps of virgin coconut oil: Synthesis, characterization, and its potential physicochemical sunscreen

Sutrisno Sutrisno — 2025-01-09

Salts of fatty acids with metals other than sodium and potassium are known as metal soaps. Triglyceride oil is an excellent source of fatty acids. Virgin coconut oil (VCO) is a source of fatty acids, with the main content being lauric acid. This study aimed to synthesize zinc, aluminum, magnesium, and calcium soaps from VCO and test their activity as sunscreens. Metal soaps were synthesized from VCO by a double decomposition reaction through sodium-VCO (Na-VCO) soap followed by trans-saponification of Na-VCO soap with chloride salts of zinc, aluminum, magnesium, and calcium giving Zn-VCO, Al-VCO, Mg-VCO, and Ca-VCO, respectively. Changing the sodium with Zn, Al, Mg, and Ca lowers the melting point, particularly Za-VCO soap, melting in the 101–126 °C range. Trans-esterification of Na-soap with those metal ions gave a high yield of up to 88.0 %, which supported the similar FTIR spectra for all metal-VCO soap except the peak shifting in 1750–1250 cm^-1 as COO- stretching vibration. The SPF values of soaps of Na-VCO, Zn-VCO, Al-VCO, Mg-VCO, and Ca-VCO are 0.43, 13.77, 3.66, 11.27, and 19.41, respectively. Metal soaps (Zn-VCO, Al-VCO, Mg-VCO, and Ca-VCO) have the potential to act as sunscreen, and Na-VCO is not potential as sunscreen. Sunscreen activity of Ca-VCO > Zn-VCO > Mg-VCO > Al-VCO.

Impact of pretreatment solution and temperature on drying of Cornelian cherry

Serhat Uz — 2025-01-09

Cornus mas L. whose common name is Cornelian cherry, mostly lives in Southern Europe and Southwest Asia naturally. One of the most popular methods for increasing food stability is drying, which lowers water activity, minimizes physical and chemical alterations, and lowers microbiological activity while materials are being stored. The effective moisture diffusivity (Deff), activation energy (Ea), drying time, and drying rate were examined in relation to different drying temperatures. Pretreated (Sod. Hyd. and Potas) / untreated (Control) Cornelian cherry samples were dried at three different temperatures (55, 65, and 75 °C). Results of study presented that the drying behaviours of Cornelian cherries are affected by using pretreatment solution and change of air temperature. Six well-known mathematical models in the literature for thin layer drying processes were applied to the experimental moisture ratio values of Cornelian cherries. Regression analysis has demonstrated that the Midilli & Küçük model, which has the highest R² value and the lowest RMSE and X² values, is the best appropriate model to explain the drying behaviour. Fick's second law was used to calculate the D_eff values. The calculated D_eff values from 1.29x10^-10 m²/s as a function of temperature increased by 5.47x10^-10 m²/s. The E_a values are of 50.74 kJ/mol, 42.07 kJ/mol and 38.88 kJ/mol for in order of Control, Sod. Hyd. and Potas samples.

Evaluation of ethanol and citric acid to increase beetroot drying performance and quality

Keli Cristina Graciola — 2025-01-09

Hot air is the most popular method for drying foods, but its performance remains a barrier in industrial scale. Beetroot is an important crop worldwide and drying is an important tool to increase foods’ shelf-life, incorpo-rate into food applications and produce dried vegetable snacks. The objective of this work was to evaluate the use of ethanol and citric acid solutions as pretreatments for the drying of beetroot. Beetroot slices were subject-ed to four different treatments before the drying proce-dure (60ºC), as follows: no wet pretreatment; wet pre-treatment; ethanol solution; and citric acid solution pretreatment. The impact on color, betalain content, and structure of beetroot slices were evaluated. Modi-fied Page model was selected to evaluate drying rates. Ethanol and citric acid solution impacted on plant tis-sue structure. Pretreatment with alcohol solution implied on increasing the drying performance of beetroot slices. Soaking beetroot slices into citric acid solution did not change drying rates compared to samples without any treatment but increases when comparison is made with samples soaked into water solution. Beetroot slices pre-treated with citric acid presented better color parameters and when they were pretreated with ethanol preserved betalain amounts after drying. Ethanol shows up as promising pretreatment for beetroot drying, enhancing process performance and maintaining quality parame-ters, meanwhile citric acid does not have great impact.

Dynamics and control of a parallel-plates reactor for ethanol steam reforming thermally coupled with catalytic ethanol combustion

Eduardo M. Izurieta — 2025-01-09

This paper analyzes the design and open-loop and closed-loop dynamics of a compact heat-integrated milli-reactor feedback control system for hydrogen production through ethanol steam reforming. The steam reforming is thermally integrated with ethanol combustion in a parallel-plates reactor. The catalysts are washcoated on metal structures separated by metal sheets. The non-steady state is studied using a rigorous modeling of the reactor to characterize the dynamics and identify variables of interest for a control system. Disturbances are caused in temperatures and flowrates, and the outlet temperature, molar composition and hydrogen yield are analyzed. The response, in terms of mass, is almost instantaneous. However, the thermal response is about 300 s until it reaches a new steady state. Flowrate to the reforming section appears as the variable to modify to satisfy changes in H₂ demand. The ethanol feed to combustion section is identified as the most feasible option to be manipulated in a control system of the temperature and composition of the generated syn-gas. The closed-loop study shows the dynamics of the reactor to set-point changes and disturbances by implementing four different control modes. The control shows satisfactory performance when changes in the set-point are applied and in none of the cases the system becomes unstable.

Microcapsules of yacon (Smallanthus sonchifolius) extracts obtained by spray dryer

Juan Soruco — 2025-01-09

The effects of spray drying on physicochemical properties, contents of bioactive compounds as well as on some individual phenolic compounds of the obtained powders were determined. The clarified extract (CE) was spray-dried with 3, 5, and 7 % maltodextrin. Permeate was spray-dried with 3 % maltodextrin. Three drying air inlet temperatures were used (Ti) 125, 145, and 175 °C and three outlet temperatures (To) 80, 90, and 100 °C The microcapsules of CE presented low values of a_w, moisture, dissolution time, hygroscopicity, bulk density, and direct reducing sugars content, when the air inlet temperature was minor. This powder showed the highest values of solubility, fructans content, phenolic compound, and antioxidant activity. The process conditions that allowed obtaining microcapsules with better characteristics and higher retention of bioactive compounds were Ti: 125 ºC, To: 100 ºC, and 5 % maltodextrin for the CE or 3 % for the permeate. Microencapsulation resulted in more effectiveness for the CE than for permeate, in terms of product characteristics and retention of bioactive.

Antioxidant and antimicrobial properties of starch-citric acid-glycerol films

Matias Alejandro Raspo — 2025-01-09

Potato starch films incorporated with citric acid as active compound and glycerol as plasticizers were evaluated in their antimicrobial and antioxidant properties. Characterization of the final films revealed commendable transparency and smoothness, often accompanied by a yellowish hue attributed to the Maillard reaction. Antimicrobial assays demonstrated activity against Staphylococcus aureus ATCC 25923. Response surface analysis indicated that starch concentration significantly influenced antioxidant responses, with citric acid enhancing the antimicrobial properties. These findings highlight the potential of citric acid enhanced starch films for ecofriendly packaging and biomedical applications, contributing to the development of functional and sustainable materials

Numerical solution of combined forced and free convective flow in porous curvilinear surfaces in presence of heat absorption/generation

Kh. Abdul Maleque — 2025-01-09

Numerical solutions for three-dimensional boundary layer mixed natural and forced convection incompressible fluid flow over the curvilinear vertical porous surfaces is examined in our present study in presence of buoyancy and heat generation/absorption effects. We transform the governing equations that is type of Prandtl thermal boundary layer equations in curvilinear system to a group of dimensionless non-linear ODEs by introducing similarity functions and variable. Missing initial conditions are found by shooting methods and the a group of ODEs is solving by Range-Kutta integration scheme of order six. Considering the different values of suction parameter and heat absorption parameter , and using MATLAB the Numerical solutions are displayed in graphical form of the profiles of velocities and temperature. Finally, the comparisons of the results highlight the justification of the numerical calculation accepted in the presence study.

Enhanced prediction of ozone concentrations using an artificial neural network model

Gediz Uguz — 2025-01-09

The primary goal of this research was to develop an Artificial Neural Network (ANN) model to predict ozone (O₃) concentrations using hourly data obtained from a monitoring station in Samsun City, located in the Middle Black Sea Region of Turkey. The dataset utilized encompassed the years from 2016 to 2020. The ANN architecture incorporated eleven input nodes representing various parameters: month, hour, concentrations of particulate matter (PM2.5 and PM10), nitrogen oxides (NOx), wind direction, relative humidity, air temperature, wind speed, cabin temperature of the measuring station, and air pressure. The focus of the model’s output was on predicting the O₃ concentration. During the training and testing phases, the ANN model displayed outstanding performance, as evidenced by correlation coefficients nearing one. The model also registered minimal values for Mean Absolute Percentage Error (MAPE, %), Mean Absolute Error (MAE) and Root Mean Square Error (RMSE). In the training phase, the model achieved a Training R-value of 0.9993, an RMSE of 0.7424, a MAPE of 4.3221%, and a MAE of 0.5301. The testing phase showed equally strong results, with a Test R-value of 0.9990, an RMSE of 0.8595, a MAPE of 4.5642%, and an MAE of 0.5823. These outcomes emphasize the model's ability to accurately predict ozone concentrations, markedly enhancing the precision compared to previous models based on traditional statistical methods. The findings of this study highlight the potential of this ANN model in providing precise ozone concentration readings in the atmosphere. The proposed ANN model distinguishes itself from previous studies by incorporating more representative variables as inputs, significantly boosting prediction accuracy. Additionally, the removal of outliers during preprocessing enhances data quality, thereby increasing the reliability of the predictions. Despite its simple structure, the model demonstrates high performance, making it both innovative and effective in comparison to earlier models. Moreover, the model's superior performance may reduce the need for additional measurement devices at newly established monitoring stations.