VLU Scholar | Browsing Journal Articles - Engineering Technology

Publication

Speckle Pattern Inversion in High Temperature DIC Measurement

( 2021)

T.Q. Thai

;

J. Ruesch

;

P.R. Gradl

;

T.T. Truscott

;

R.B. Berke

During hot fire rocket engine testing, non-contacting measurements are superior to bonded gauges because they are immune to burning, shaking loose, or damage due to the harsh testing conditions. Additionally, when compared to instruments which register at single points, Digital Image Correlation (DIC) has the added benefit in that it collects full-field displacement and strain maps over the duration of the test. However, for certain materials and paints under some circumstances of temperature and camera sensitivity, portions of the speckle pattern which were darker at room temperature may emit more light compared to the initially lighter portions of the pattern, resulting in a high temperature pattern which is inverted in comparison with that at room temperature. To address this inversion, a post-processing method is introduced wherein an inverted image containing only emitted light is subtracted from an image containing both emitted and reflected light, thereby generating an un-inverted image. The artificial high temperature image is subsequently correlated against the room temperature image to obtain full-field strains. The subtraction technique is then validated using optical bandpass filters to prevent significant amounts of emitted light from reaching the camera sensor. The two methods are mapped onto common coordinates and shown to produce comparable results. The subtraction method sufficiently mitigates speckle pattern inversion, but its key drawback is that it only works when there is negligible displacement between the subtracted images (i.e. quasi-static loading). It is therefore preferable to eliminate inversion from reaching the camera in the first place by using optical bandpass filters.

Publication

Regularization of the backward stochastic heat conduction problem

( 2021)

Nguyen Huy Tuan

;

Daniel Lesnic

;

Tran Ngoc Thach

;

Tran Bao Ngoc

In this paper, we study the backward problem for the stochastic parabolic heat equation driven by a Wiener process. We show that the problem is ill-posed by violating the continuous dependence on the input data. In order to restore stability, we apply a filter regularization method which is completely new in the stochastic setting. Convergence rates are established under different a priori assumptions on the sought solution.

Publication

Phytoremediation potential of Gossypium hirsutum on abandoned polluted chromium sludge soil with the amalgamation of Streptomyces tritici D5

( 2022)

Mathiyazhagan Narayanan, Indira Karuppusamy, Maha Alshiekheid, Amal Sabour, Nguyen Thuy Lan Chi, Arivalagan Pugazhendhi

The phytoremediation potency of Gossypium hirsutum was explored in this research under the influence of preidentified metal tolerant Streptomyces tritici D5 in Cr enriched sludge soil using various treatment sets (I to V) in a greenhouse setting. Interestingly, the G. hirsutum remarkable remediate the Cr metal from the Cr enriched sludge soil under diluted (50:50) condition in 90 days of greenhouse experiment. The S. tritici D5 also effectively support the growth and phytoremediation competence of G. hirsutum. This was evidenced by the under the diluted (set III) condition the growth and major biomolecules such as protein, carbohydrate, and chlorophyll content of G. hirsutum were considerably increased in quantity. Hence, the phytoremediation potential of G. hirsutum was effective at soil diluted with fertile and xenobiotics free soil with dilution ratio of 50:50 (set III) and followed by 75:25 (set II) ratio. Thus, under diluted conditions (50:50) G. hirsutum seed coated with S. tritici D5 showed an outstanding phytoremediation process. Therefore, this method can be implemented to the field level study to assess the metal removal prospects of this environmentally friendly method.

Publication

On a terminal value problem for parabolic reaction–diffusion systems with nonlocal coupled diffusivity terms

( 2022)

Nguyen Huy Tuan

;

Tomás Caraballo

;

Phan Thi Khanh Van

;

Vo Van Au

In this article, we are interested in investigating the nonlocal nonlinear reaction–diffusion system with final conditions. This problem is called backward in time problem, or terminal value problem which is understood as redefining the previous distributions when the distribution data at the terminal observation are known. There are three main goals presented in this paper. First, we prove that the problem is ill-posed (often called as unstable property) in the sense of Hadamard. Our next propose is to provide a modified quasi-reversibility model to stabilize the ill-posed problem. Using some techniques and tools of Faedo–Galerkin method, we prove the existence of the unique weak solution of the regularized problem. Further, we investigate error estimates between the sought solution and the regularized solution in and norms. The final aim of this paper is to give some numerical results to demonstrate that our method is useful and effective.

Publication

Bioremediation competence of Aspergillus flavus DDN on pond water contaminated by mining activities

( 2022)

Wongchai Anupong, Khumchai Jutamas, Ruangwong On-uma, Maha Alshiekheid, Amal Sabour, Ramakrishnan Krishnan, Nguyen Thuy Lan Chi, Arivalagan Pugazhendhi, Kathirvel Brindhadevi

This research was performed to evaluate the possibilities of reducing the physicochemical properties of polluted pond water situated around the magnesite mine tailing through indigenous metal tolerant fungi. The physicochemical analysis results revealed that most of the physicochemical properties of pond water sample were crossing the permissible limits. From the muddy pond soil sample, Aspergillus flavus DDN was identified (through molecular characterization) as predominant metal tolerant fungal strain and it showed resistance to Cr(VI), Pb (II), Zn(II), Cd(II), and Mg(IV) up to 1000 μg mL􀀀 1 concentrations. This strain also effectively reduced (through biosorption) these metals in a short duration of the bioremediation process. In a lab-scale bioremediation study the A. flavus DDN significantly reduced most of the physicochemical parameters crossing the permissible limit in polluted pond water in the presence of FM1 minimal media in 10 days of incubation. The dissolved oxygen level was significantly increased up to 74.91% from 5.86 ± 0.39 to 10.25 ± 0.95 in 10 days of treatment. The metal reduction and other physicochemical properties reduction were directly related to the biomass of A. flavus DDN. These findings suggest that A. flavus DDN can remove pollutants from magnesite mine tailing polluted pond water because elevated fungal biomass resulted in the highest percentage of pollutant reduction from the sample.

Publication

Prediction of the fuel spray characteristics in the combustion chamber with methane and TiO2 nanoparticles via numerical modelling

( 2022)

Dongwei Shao, Sami Al Obaid, Sulaiman Ali Alharbi, Josef Marouˇsek, Manigandan Sekar, P. Gunasekar, Nguyen Thuy Lan Chi, Kathirvel Brindhadevi, Junfa Wang, Donghua Jiang

In this study the methane combustion was analysed with the TiO2 nanoparticles. A series of the simulation runs were performed by varying the fuel inlet velocity. However, the oxidizer and the nanoparticles spray were maintained constant for the entire run. The spray velocity varied from 100 m/s to 200 m/s with titanium dioxide (TiO2) nanoparticles. Using the series of the governing equation and modified Navier Stokes equation the model has been developed with the aid of numerical workbench. Three different domains are generated for fuel, oxidizer and nanoparticles. The velocity of the air and nanoparticles were maintained at constant levels and varying only the spray velocity of the fuel. Based on the findings, the mass fraction of both fuel and formation of the CO2 were dependent on the spray velocity. As the spray velocity increases the turbulence in the combustion chamber increases which ensures the higher mixing of both air–fuel and nanoparticles. From the procured findings 175 m/s and 200 m/s were the ideal range for better combustion efficiency compared to 100 m/s and 150 m/s. The simulation results have ascertained the role of the spray velocity on the emissions and the combustion efficiency of the engine. It is hoped that obtained results can provide directions to work on the combustion of the methane with the nanoparticles at the optimized spray velocity.

Publication

Approximation of the initial value for damped nonlinear hyperbolic equations with random Gaussian white noise on the measurements

( 2022)

Phuong Nguyen Duc

;

Erkan Nane

;

Omid Nikan

;

Nguyen Anh Tuan

The main goal of this work is to study a regularization method to reconstruct the solution of the backward non-linear hyperbolic equation $ u_{tt} + \alpha\Delta^2u_t +\beta \Delta ^2u = \mathcal{F}(x, t, u) $ come with the input data are blurred by random Gaussian white noise. We first prove that the considered problem is ill-posed (in the sense of Hadamard), i.e., the solution does not depend continuously on the data. Then we propose the Fourier truncation method for stabilizing the ill-posed problem. Base on some priori assumptions for the true solution we derive the error and a convergence rate between a mild solution and its regularized solutions. Also, a numerical example is provided to confirm the efficiency of theoretical results

Publication

Mild solutions to a time-fractional Cauchy problem with nonlocal nonlinearity in Besov spaces

( 2022)

Nguyen Huy Tuan

;

Vo Van Au

;

Anh Tuan Nguyen

"In this paper, we aim to study a time-fractional Cauchy problem for a heat equation with a nonlocal nonlinearity driven by simulation problems arising in populations, and biological mathematics. Using the Banach fixed-point argument, we investigate the existence and uniqueness of mild solutions in Besov spaces defined on an open subset of RN. The key tools of our method are some linear estimates of the heat semigroup generated by the Dirichlet Laplacian and techniques of the M-Wright function. Some embeddings are also used for our proofs."

Publication

Fabrication, characterization, anti-inflammatory, and anti-diabetic activity of silver nanoparticles synthesized from Azadirachta indica kernel aqueous extract

( 2022)

Nguyen Thuy Lan Chi, Mathiyazhagan Narayanan, Arunachalam Chinnathambi, Chandramohan Govindasamy, Baskaran Subramani, Kathirvel Brindhadevi, Tipsukon Pimpimon, Surachai Pikulkaew

The Azadirachta indica is an excellent and pharmaceutically valuable phytochemicals enriched traditional medicinal plant. The purpose of the research was to assess the ability of A. indica aqueous kernel extract to synthesize silver nanoparticles as well as their anti-inflammatory and anti-diabetic activity in vitro. The obtained results state that the aqueous kernel extract of A. indica can fabricate the silver nanoparticles and be confirmed by standard analytical techniques. Under UV–visible spectrophotometer analysis, the absorbance peak was found at 430 nm was related to the surface plasmon resonance of silver nanoparticles. The FTIR (Fourier-transform infrared spectroscopy) analysis revealed that numbers of functional groups belong to the pharmaceutically valuable phytochemicals, which act as reducing, capping, and stabilizing agent on silver nanoparticles synthesis. The size and shape of the silver nanoparticles were examined as 19.27–22.15 nm and spherical in shape. Interestingly, this kernel fabricated silver nanoparticles possess a reasonable anti-inflammatory (69.77%) and anti-diabetic (73.5%) activity at 100 μg mL􀀀 1 and these were partially comparable with standards (anti-inflammatory: 81.15%; anti-diabetic: 87.9%). Thus, the aqueous kernel extract fabricated silver nanoparticles can be considered for further in-vivo study to assess the practical possibility to promote as a pharmaceutical agent.

Publication

Sustainable bioremediation approach to treat the sago industry effluents and evaluate the possibility of yielded biomass as a single cell protein (SCP) using cyanide tolerant Streptomyces tritici D5

( 2022)

Wongchai Anupong, Khumchai Jutamas, Ruangwong On-uma, Amal Sabour, Maha Alshiekheid, Indira Karuppusamy, Nguyen Thuy Lan Chi, Arivalagan Pugazhendhi

This sustainable approach was performed to evaluate the bioremediation potential of cyanide resistant bacterial species on sago industry effluents and assess the possibility of using the yielded biomass as single cell protein (SCP). The predominant cyanide tolerant bacterium enumerated from muddy soil was identified as Streptomyces tritici D5 through 16S rRNA sequencing. The identified S. tritici D5 strains showed excellent resistant and degradation potential at 100 mM concentration of potassium cyanide. Furthermore, the physicochemical properties analysis of sago industry effluents results revealed that the most of the parameters were crossing the permissible limits of Pollution control board of India. The bioremediation process was performed at various temperatures at 25 ◦C, 35 ◦C, and 45 ◦C for a period of 30 days of continuous bioremediation process with the aid of an aerator. Surprisingly, the best organic pollutant reduction was found at 35 ◦C and 45 ◦C, with 25 ◦C following close behind. Remarkably, the dissolved oxygen (DO) level was gradually increased from 2.24 to 12.04 mg L􀀀 1 at 35 ◦C in 30 days of the remediation process. The pH and ammonia were also significantly increased during the bioremediation process in 30 days of treatment. Similarly, at 35 ◦C of bioremediation process the S. tritici D5 yielded maximum dried biomass (6.9 g L􀀀 1) with the total crude protein (SCP) as 4.8 g L􀀀 1 (69.56%) in 30 days of growth. These findings stated that S. tritici D5 can treat sago industry effluents and that the biomass produced may be considered SCP after some in-vitro and in-vivo analyses.

Publication

In vitro analysis of green synthesized copper nanoparticles using Chloroxylon swietenia leaves for dye degradation and antimicrobial application

( 2022)

Yan Yuan, Yingji Wu, V. Chinnadurai, Mythili Saravanan, Arunachalam Chinnathambi, Sulaiman Ali Alharbi, Kathirvel Brindhadevi, Nguyen Thuy Lan Chi, Arivalagan Pugazhendhi

Green fabrication of copper nanoparticles (CuNPs) is an environmentally friendly and cost-effective method of synthesis for biomedical and bioremediation applications. In recent times, bacterial pathogens contaminating or affecting food and food crops pose the greatest threat to the food industry. In addition to this issue, synthetic dyes released from the textile and dyeing industries are polluting aquatic ecosystems and agricultural lands. The combined impact of these two factors is considered a major threat to life. Therefore, the use of CuNPs will provide an effective and long-term solution as an antibacterial and dye removing agent. The current study focuses on the synthesis of CuNPs using the leaf extract of Chloroxylon swietenia (C-CuNPs). The formation of a peak at 390 nm and a change in color from yellow to dark brown confirmed the synthesis of C-CuNPs. Subsequent synthesis at pH 9 was suitable for preparing C-CuNPs. Structural and chemical characterization of C-CuNPs was performed using Fourier Transfer Infra-Red (FTIR), X-ray diffraction (XRD), Dynamic Light scattering (DLS), and Scanning Electron Microscopy (SEM) analysis. The synthesized C-CuNPs possess a crystalline nature, a functional group that resembles C. swietenia, and are negatively charged and spherical in shape. C-CuNPs were tested against Congo red, Coomassie blue, and crystal violet and they showed complete degradation within 24 h under optimum conditions. Disk diffusion and broth dilution assay were used to test the antibacterial activity of CCuNPs against Staphylococcus nepalensis, Staphylococcus gallinarum, Pseudomonas stutzeri, Bacillus subtilis, and Enterococcus faecalis. Therefore, the present study represents the first report on C-CuNPs’ ability to degrade synthetic dyes and kill foodborne bacterial pathogens. Thus, the study has shed light on the potential of green synthesized CuNPs as bioremediation and packaging material in the future.

Publication

Machine learning-based real-time daylight analysis in buildings

( 2022)

Luan Le-Thanh

;

Ha Nguyen-Thi-Viet

;

Jaehong Lee

;

H. Nguyen-Xuan

Daylight analysis is essential in building design to ensure indoor environment quality, including health and thermal comfort vis-à-vis energy. It is a repeating and time-consuming process of design options. Several studies conducted machine learning models to accurately predict daylight performance in particular design situations. Therefore, developing an AI-based real-time daylight analysis platform becomes more promising. However, buildings can be designed with arbitrary shapes, creating a real challenge for the AI to recognize any building layout. From that perspective, the idea of finding the design variables that characterize all the building layouts becomes the key solution. To unlock this challenge, we promote a novel method of creating design variables and building a machine learning model that can efficiently forecast daylight performance with different building layouts. The daylight metric was Useful Daylight Illuminance with four ranges, and the case studies were assumed medium-sized buildings located in Ho Chi Minh City, Vietnam. All the data for training and predicting were created by the simulation DIVA tool. Obtained results showed the excellent performance of the proposed approach, which brings more promising in developing a data-driven machine learning platform for real-time daylight validation. Moreover, the present framework can adapt to any specific machine learning model or daylight simulation tool and daylight metrics.

Publication

Plant resistance to disease: Using biochar to inhibit harmful microbes and absorb nutrients

( 2022)

Jinbo Hou, Arivalagan Pugazhendhi, Tran Nhat Phuong, Nguyen Chi Thanh, Kathirvel Brindhadevi, Gomathi Velu, Nguyen Thuy Lan Chi, Deyi Yuan

Phytosanitary concerns are part of today’s agricultural environment. The use of chemicals to treat plant diseases is both a source of pollution and allows pathogens to become resistant. Additionally, it can improve the chemical, physical, and biological properties of soil. Therefore, the soil environment is more conducive to healthy plant growth. By improving the chemical, physical, and biological attributes of soil, biochar can enhance plant resistance. Agricultural success has been attributed to biochar’s acidic pH, which promotes beneficial soil microorganisms and increases soil nutrients; it is also porous, which provides a home and protects soil microorganisms. By improving soil properties, biochar becomes even more effective at controlling pathogens. The article also discusses the benefits of biochar for managing pathogens in agricultural soils. In addition, we examine several research papers that discuss the use of biochar as a method of combating soil-related pathogens and plant diseases. Biochar can be used to combat soil-borne diseases and other conditions

Publication

Silk fibroin hydrogel containing Sesbania sesban L. extract for rheumatoid arthritis treatment

( 2022)

Duy Toan Pham

;

Nguyen Thi Phuong Thao

;

Bui Thi Phuong Thuy

;

Van De Tran

;

Thanh Q. C. Nguyen

;

Ngoc Nha Thao Nguyen

Purpose: Rheumatoid arthritis, a chronic and progressive inflammation condition in the joints, has significantly reduced the patient quality of life and life expectancy. Crucially, there is no complete therapy for this disease, and the current treatments possess numerous side effects. Thus, novel therapeutic approach is necessary. To that end, this study developed novel silk fibroin in-situ hydrogel containing Sesbania sesban L. extract, a plant with high anti-inflammatory actions that are beneficial for rheumatoid arthritis treatments. Methods: The hydrogels were manufactured using simple method of spontaneous gelation at different temperature. The gel properties of morphology, gelation time, viscosity, gel strength, stability, drug loading capacity, drug release rate, and in-vitro anti-inflammatory activity were investigated with appropriate methods. Results: The optimal formulation had highly porous structure, with a gelation time of 0.5 h at room temperature and bodily temperature of 37 C, a viscosity of 2530 ± 50 cP, a gel strength of 1880.14 ± 35.10 g, and a physical stability of >6months. Moreover, the hydrogel contained the Sesbania sesban L. leaf extract with a total phenolic content of 92.8 ± 8.30mg GAE/g, and sustained the release rate for >20 da: ys, followed the Higuchi model. Regarding the in-vitro activities, all formulations were nontoxic to the RAW 264.7 cell line and demonstrated comparable anti-inflammatory activity to the free extract, in terms of the NO reduction levels. Conclusion: Conclusively, the systems possessed potential properties to be further investigated to become a prospective rheumatoid arthritis treatment.

Publication

Impacts of oxygen and ozone nanobubbles on bacteriophage in aquaculture system

( 2022)

Le Thanh Dien

;

Nguyen Vu Linh

;

Thao Thu Mai

;

Saengchan Senapin

;

Sophie St-Hilaire

;

Channarong Rodkhum

;

Ha Thanh Dong

Injection of ozone nanobubbles into water reduces bacterial load, improves dissolved oxygen, and modulates the fish innate immune system. Little is known about the effect that nanobubble treatment has on the concentration of viruses in water. This study, investigated the disinfection impact of oxygen and ozone nanobubbles (NB-O2 and NB-O3) on an Aeromonas hydrophila-specific phage, pAh6.2TG, a virus lab model. After 5-, 10- and 15-min treatments with NB-O2, the concentration of phage remained the same, while the same treatment with NB-O3 eradicated 99.99 to 100% of the phage in the water. Since this phage has been shown to control bacterial infections in fish, we further investigated whether NB-O2 improved the adherence of the phage to the body surface of the fish (i.e. skin mucus, and gills) and phage penetration into fish internal organs, specifically the liver. Nile tilapia, Oreochromis niloticus were used as experimental fish in this study. The results indicated that the number of phages adhered to the skin mucus and gills in NB-O2 treatment group was 1.07 to 15.0 times higher than in the untreated control group without gas nanobubbles. The phage uptake into fish liver after NB-O2 treatment increased 1.29 to 4.75 fold compared to untreated control. These findings suggested a plausible application of NB-O2 treatment for improving efficacy of phage therapy in aquaculture. On the other hand, NB-O3 application may be useful for disinfection of harmful viruses in culture water, but the application would need to be omitted during phage treatment. This study provides preliminary information on potential applications of nanobubble technology in aquaculture to reduce viral load in the water.

Publication

Structural, optical and conductivity properties in tetragonal BaTi_1−xCo_xO₃ (0≤ x ≤0.1)

( 2022)

L. T. H. Phong

;

N. T. Dang

;

N. V. Dang

;

Van-Quynh Nguyen

;

D. H. Manh

;

P. H. Nam

;

L. H. Nguyen

;

P. T. Phong

"This work investigates the structure, optical and electrical conductivity properties of BaTi1 xCoxO3 (0# x #0.1) ceramics prepared by the hydrothermal method. The X-ray diffraction and Raman scattering analysis demonstrates that the prepared samples have a single-phase tetragonal structure with P4mm symmetry. The UV-vis diffuse reflectance spectrum confirms the influence of Co concentration on the direct optical band gap of BaTi1 xCoxO3 ceramics. The optical band gap shifts from 3.14 eV to 3.44 eV as the Co concentration increases from 0 to 0.1. The dielectric constant increases with the depletion of frequency according to the Maxwell–Wagner and Koops model. The AC conductivity versus frequency curve indicates that the conduction mechanism is determined by using the correlated barrier hopping (CBH) model. The Cole–Cole plot of the complex impedance was investigated for the prepared samples. The compounds showed dielectric relaxation of the non-Debye type."

Publication

Influence of Brevibacillus borestelensis strains on phytoremediation potential and biomolecules contents of Jatropha curcas on diluted chromium sludge soil

( 2022)

Mathiyazhagan Narayanan, Muthusamy Muthusamy, Maha Alshiekheid, Amal Sabour, Nguyen Thuy Lan Chi, Arivalagan Pugazhendhi

This study was carried out in order to find an environmentally friendly solution to recover the abandoned Crenriched sludge soil, which causes a variety of environmental issues. Hence, in this research the influence of pre-identified Brevibacillus borstelensis UTM105 and Brevibacillus borstelensis AK2 coated Jatropha curcas seed in phytoremediation process with various treatment groups (group A to F) under greenhouse condition. Furthermore, their influence on growth, biomolecules (total proteins and total chlorophyll) content, and antioxidant activity of J. curcas during the phytoremediation process were analyzed. Surprisingly, the outstanding phytoremediation was recorded in group F treatment. In these groups, Group E. accompanied it, and the Cr was reduced by up to 31.17% and 25.65%, respectively, in treated soil after 90 days of treatment. Among these two bacterial strains, the B. borstelensis AK2 had greatest effect on J. curcas growth, the yield of biomass, total protein, total chlorophyll, and antioxidant activity and it followed by B. borstelensis UTM105. These phytoremediation potential of J. curcas was effective at soil diluted with fertile and xenobiotics free soil with dilution ratio of 50:50 and followed by 75:25 ratio. Because under undiluted Cr sludge soil condition seed germination has not occurred even though the seed has been coated with potential bacterial strains and soil blend with sterilized goat manure. Hence, under diluted conditions J. curcas seed coated with B. borstelensis AK2 showed an outstanding phytoremediation process. Hence, this approach can be applied to a field study to assess the metal removal potential of this sustainable approach.

Publication

Microwave assisted biodiesel production from chicken feather meal oil using Bio-Nano Calcium oxide derived from chicken egg shell

( 2022)

Minglong Zhang, Ganesan Ramya, Kathirvel Brindhadevi, Mishal Alsehli, Ashraf Elfasakhany, Changlei Xia, Nguyen Thuy Lan Chi, Arivalagan Pugazhendhi

Environmental concerns have initiated the search for greener measures to mitigate pollution issues. Bio Nano CaO was synthesized by reducing CaO extracted from chicken egg shell using tea decoction. The synthesized material was characterized by physico-chemical techniques such as XRD, TGA, BET surface area analyser, TGA and SEM techniques. XRD studied confirmed the crystalline nature of material. The prepared material was found to be stable till 450 οC from TGA study. The SEM pictures displayed uniform and discrete particles which portrays the high probable sites that maximises the catalytic activity. The optimization of microwave assisted Biodiesel synthesis from chicken feather oil through Transesterification process using the bio-synthesized catalytic material was the main aim of the study. A 500 W microwave irradiation of Chicken feather meal oil using 8:1 Methanol:Oil input, 1% Bio Nano CaO concentration, 5 min of reaction time resulted in 95% conversion of chicken feather meal oil into chicken feather meal methyl esters. The Biodiesel was showed low viscosity (4.15 mm2/s), high heating value (50 MJ/kg), high flash point (153οC), reasonable pour point (12 οC) and good cetane number (50 min). The future works will be concentrated on the engine studies related to Torque, fuel consumption, emission data by using the synthesized Biodiesel.

Publication

UAV caching in 6G networks: A Survey on models, techniques, and applications

( 2022)

Trung Q. Duong

;

Kyeong Jin Kim

;

Zeeshan Kaleem

;

Minh-Phung Bui

;

Nguyen-Son Vo

The rapid development road map of 6G networks has posed a new set of challenges to both industrial and academic sectors. On the one hand, it needs more disruptive technologies and solutions for addressing the threefold issues including enhanced mobile broadband, massive machine-type communications, and ultra-reliable and low-latency communications. On the other hand, the ever-massive number of mobile users and Internet of Things devices conveys the huge volume of traffic throughout the 6G networks. In this context, caching is one of the most feasible technologies and solutions that does not require any system architecture changes nor costly investments, while significantly improve the system performance, i.e., quality of service and resource efficiency. Ground caching models deployed at macro base stations, small-cell base stations, and mobile devices have been successfully studied and currently extended to the air done by unmanned aerial vehicles (UAVs) to deal with the challenges of 6G networks. This paper provides a comprehensive survey of UAV caching models, techniques, and applications in 6G networks. In particular, we first investigate the entire picture of caching models moving from the ground to the air as well as the related surveys on UAV communications. Then, we introduce a typical UAV caching system and describe how it works in connection with all types of the transceivers, end users, and applications and services (A&Ss). After that, we present the recent advancements and analyses of the UAV caching models and common system performance metrics. Furthermore, the UAV caching with assisted techniques, UAV caching-enabled mechanisms, and UAV caching A&Ss are discussed to demonstrate the role of UAV caching system in 6G networks. Finally, we highlight the ongoing challenges and potential research directions toward UAV caching in 6G networks.

Publication

Small scale photobioreactor, outdoor open pond cultivation of Chlorella sp. and harvesting at log and stationary growth phase towards lipids and methyl ester production

( 2022)

Nguyen Thuy Lan Chi, Thangavel Mathimani, S. Manigandan, Sabarathinam Shanmugam, Nguyen Thi Ha, Tran Cam Nhung, Sulaiman Ali Alharbi, Arunachalam Chinnathambi, Kathirvel Brindhadevi, Usawadee Chanasut, Kanda Whangchai

Microalgae are the promising feedstock for biodiesel production than other first and second-generation feedstocks. Generating huge biomass sustainably per unit volume per day is vital to the continuous utilization of algal feedstock for sustainable biodiesel production. But, cultivation and harvesting of microalgae are the significant cost drivers and the commonly used cultivation systems for microalgae are outdoor pond and photobioreactor. In this study, small scale photobioreactor, outdoor open pond and Erlenmeyer flask based cultivation of Chlorella sp. and harvesting at log phase and stationary phase for biomass, lipids towards FAME (fatty acid methyl ester) production was investigated. Photobioreactor grown Chlorella sp. showed higher growth in terms of biomass yield, biomass productivity and chlorophyll content. In the case of lipid content, Chlorella sp. unveiled a similar percentage of lipid about 20% (log phase) and 24% (stationary phase) irrespective of the cultivation systems tested. Non-polar lipid percentage 46% in log phase, while in stationary phase, Chlorella sp. showed higher levels of non-polar lipids at about 66% in photobioreactor and open pond systems. A similar pattern of fatty acids was seen from cultures grown in all three cultivation systems and among identified fatty acids, γ-linolenic acid is prevalent in the range between 14 and 15% followed by palmitic acid in the range between 11 and 13%.

Journal Articles - Engineering Technology - 2022

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