Optimization of the eco-friendly synthesis of graphene oxide from graphite using Plackett–Burman and Box–Behnken models for industrial production orientation

Phuc Nguyen Thien,Giang Nguyen Thi Huong,An Vu Nguyen Thien Truong,Nam Nguyen Thanh Hoai,Anh Ly Duc,Nguyen Huynh Cam,An Hoang,Phong Mai Thanh,Hieu Nguyen Huu 한국탄소학회 2023 Carbon Letters Vol.33 No.2

In this study, graphene oxide (GO) was synthesized by the improved Hummers’ method. The degree of oxidation from graphite (Gi) to GO was determined through interlayer spacing calculated from X–ray diffraction. Besides, the effect of KMnO4:Gi ratios (X1), H2SO4 volume (X2), oxidation temperature (X3), oxidation time of stage 1 (X4), and oxidation time of stage 2 (X5) was screened by the Plackett–Burman model. The simultaneous impact of three factors that influenced the degree of oxidation (X1, X2, and X3) was studied by the Box–Behnken experimental model of response surface methodology to achieve suitable conditions for the GO synthesis process. The characterization of GO product was investigated via the modern analytical methods: X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, UV–Vis spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. In addition, the study was also carried out on a pilot scale for orientation in industrial application with the yield of 14 g/batch.

Consumer Perceptions and Consumer Behavior Toward Bio-Based Products: An Empirical Study in Vietnam

Trong Luan NGUYEN,Ngoc Phu TRAN,Thi Kieu Thu NGUYEN,Thi Cam Tien HUYNH,Thi Kim Loi NGUYEN,Le Phuong Nghi THACH,Gia Nhu THAI,Thi Thanh Sang TRAN 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.12

Green economy, also known as sustainable economy, is a current development trend in which consumers prefer products that are wholly or partly derived from materials of biological origin since they have become more concerned about their health and the environment in which they live. This study aims to examine consumer behavior toward bio-based products with three key goals in mind. First, it helps to understand the perception of consumers toward Bio-based products. Second, it properly helps consumers be aware of products derived from materials of biological origin so that the consumer can make purchasing decisions to protect their health and contribute to the protection of the environment. Third, the study on consumer behavior towards bio-based products will provide a more accurate view and assessment to companies looking to develop Bio-based products. Based on that, the research is carried out through surveying, collecting data from consumers, and then using the deductive approach, descriptive statistics, and quantitative method analysis. The results demonstrated that a positive relationship and a direct impact are established between the variables of Attitude and Social Norms and the Purchase Intention toward Bio-based products. Furthermore, the findings reveal that customers have positive feelings towards bio-based products in terms of trust, knowledge, and the environment.

α-Calcium sulfate hemihydrate bioceramic prepared via salt solution method to enhance bone regenerative efficiency

Dieu Linh Tran,Anh Phuong Nguyen Hong,Ngoc Hoi Nguyen,Ngoc Trinh Huynh,Bao Ha Le Tran,Cam Tu Tran,Minh Dung Truong,Quan Dang Nguyen,박기동,Dai Hai Nguyen 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.120 No.-

α-calcium sulfate hemihydrate (α-HH) was synthesized by salt solution methods to prepare a promising biomaterial for bone tissue repair and regeneration. The successful synthesis of α-HH was evaluated by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) scanning. The sterility of α-HH before and after irradiation with gamma ray was firstly confirmed by Colonies Forming Units (CFU) counting assay, to target the surgical grade application. In vitro tetrazolium bromide (MTT) assay, crystal violet (CV) and acridine orange (AO) staining was performed to assess the initial cytotoxicity and cell attachment ability of α-HH. Further in vivo implantation into rabbit distal femoral condyles defect exhibited the ability of salt solution-synthesized α-HH to promote the localization of osteocytes and osteoblasts, which improve the bone tissue repair and regeneration. The findings suggested that α-calcium sulfate hemihydrate synthesized by salt solution method is a potential material that can be used as bone substitutes.

Selective bit embedding scheme for robust blind color image watermarking

Huynh-The, Thien,Hua, Cam-Hao,Tu, Nguyen Anh,Hur, Taeho,Bang, Jaehun,Kim, Dohyeong,Amin, Muhammad Bilal,Ho Kang, Byeong,Seung, Hyonwoo,Lee, Sungyoung Elsevier 2018 Information sciences Vol.426 No.-

<P>In this paper, we propose a novel robust blind color image watermarking method, namely SMLE, that allows to embed a gray-scale image as watermark into a host color image in the wavelet domain. After decomposing the gray-scale watermark to component binary images in digits ordering from least significant bit (LSB) to most significant bit (MSB), the retrieved binary bits are then embedded into wavelet blocks of two optimal color channels by using an efficient quantization technique, where the wavelet coefficient difference in each block is quantized to either two pre-defined thresholds for corresponding 0-bits and 1-bits. To optimize the watermark imperceptibility, we equally split the coefficient modified quantity on two middle-frequency sub-bands instead of only one as in existing approaches. The improvement of embedding rule increases approximately 3 dB of watermarked image quality. An adequate trade-off between robustness and imperceptibility is controlled by a factor representing the embedding strength. As for extraction process, we exploit 2D Otsu algorithm for higher accuracy of watermark detection than that of 1D Otsu. Experimental results prove the robustness of our SMLE watermarking model against common image processing operations along with its efficient retention of the imperceptibility of the watermark in the host image. Compared to state-of-the-art methods, our approach outperforms in most of robustness tests at a same high payload capacity. (C) 2017 Elsevier Inc. All rights reserved.</P>

Hierarchical topic modeling with pose-transition feature for action recognition using 3D skeleton data

Huynh-The, Thien,Hua, Cam-Hao,Anh Tu, Nguyen,Hur, Taeho,Bang, Jaehun,Kim, Dohyeong,Amin, Muhammad Bilal,Kang, Byeong Ho,Seung, Hyonwoo,Shin, Soo-Yong,Kim, Eun-Soo,Lee, Sungyoung Elsevier science 2018 Information sciences Vol.444 No.-

<P><B>Abstract</B></P> <P>Despite impressive achievements in image processing and artificial intelligence in the past decade, understanding video-based action remains a challenge. However, the intensive development of 3D computer vision in recent years has brought more potential research opportunities in pose-based action detection and recognition. Thanks to the advantages of depth camera devices like the Microsoft Kinect sensor, we developed an effective approach to in-depth analysis of indoor actions using skeleton information, in which skeleton-based feature extraction and topic model-based learning are two major contributions. Geometric features, i.e. joint distance, joint angle, and joint-plane distance are calculated in the spatio-temporal dimension. These features are merged into two types, called pose and transition features, and then are provided to codebook construction to convert sparse features into visual words by <I>k</I>-means clustering. An efficient hierarchical model is developed to describe the full correlation of feature - poselet - action based on Pachinko Allocation Model. This model has the potential to uncover more hidden poselets, which have been recognized as the valuable information and help to differentiate pose-sharing actions. The experimental results on several well-known datasets, such as MSR Action 3D, MSR Daily Activity 3D, Florence 3D Action, UTKinect-Action 3D, and NTU RGB+D Action Recognition, demonstrate the high recognition accuracy of the proposed method. Our method outperforms state-of-the-art methods in the field in most dataset benchmarks.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 3D action recognition approach using topic modeling technique. </LI> <LI> Pose and transition feature for object posture and movement representation. </LI> <LI> A flexible hierarchical topic model to learn feature-poselet-action correlation. </LI> <LI> Method sensitivity evaluation on five well-known 3D action recognition datasets. </LI> <LI> Accuracy improvement to other existing methods which only use 3D skeleton data. </LI> </UL> </P>

Phytoplankton composition in intensive shrimp ponds in Bac Lieu province, Vietnam

Nguyen Thi Kim Lien,Phan Thi Cam Tu,Vo Nam Son,Huynh Truong Giang 한국수산과학회 2023 Fisheries and Aquatic Sciences Vol.26 No.8

Algal overgrowth in shrimp culture ponds can affect the quality of the aquatic environment, thereby adversely affecting the shrimp and causing economic losses. The objective of this study was to evaluate the variation in phytoplankton composition in intensive shrimp ponds in Bac Lieu province, Vietnam. Phytoplankton samples were collected in three black tiger shrimp (Penaeus monodon) ponds and three whiteleg shrimp (Litopenaeus vannamei) ponds. The collected data were analyzed using SPSS and canonical correlation analysis softwares. In total, 75 species of phytoplankton were recorded in black tiger shrimp ponds and 64 species in whiteleg shrimp ponds. Diatoms had the highest species diversity with 29–30 species (39%–47%), followed by green algae with 9–19 species (14%–25%); species numbers of other phyla varied from 5–12 (8%–16%). The total number of phytoplankton species throughout the study varied from 34–50 species. Algal density was relatively high and ranged from 497,091–2,229,500 ind./L and 1,301,134–2,237,758 ind./L in black tiger shrimp and whiteleg shrimp ponds, respectively. The diatom density tended to increase during the final stage of the production cycle in black tiger shrimp ponds. Blue-green algae and dinoflagellates also increased in abundance at the end of the cycle, which can affect shrimp growth. Diatoms were significantly positively correlated with pH, salinity, total ammonia nitrogen, and nitrate (NO3 –) concentrations (p < 0.05). Blue-green algae and dinoflagellates were positively correlated with salinity, phosphate (PO4 3–), and NO3 –. Algal species diversity was lower in the whiteleg shrimp ponds than in the black tiger shrimp ponds. Several dominant algal genera were recorded in the shrimp ponds, including Nannochloropsis, Gyrosigma, Chaetoceros, Alexandrium, and Microcystis. The results of this study provide basic data for further investigations, and they contribute to the management of algae in brackish-water shrimp ponds.

Fabrication and modification of cellulose aerogels from Vietnamese water hyacinth for oil adsorption application

La Nam Phat,Tran Quoc Thang,Huynh Cam Nguyen,Dang Thi My Duyen,Dao Xuan Tien,Bui Dang Dang Khoa,Pham Tan Khang,Nguyen Thi Huong Giang,Hoang Minh Nam,Mai Thanh Phong,Nguyen Huu Hieu 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.11

Recycling biomass to cellulose aerogel (Cell-A) provides a promising approach to develop adsorbent materials for spilled-oil recovery. In this work, Cell-A was fabricated from Vietnamese water hyacinth via crosslinking methods using PVA as a crosslinker and freeze-drying process. Various cellulose to PVA ratios were investigated to obtain the optimal synthesis condition. The Cell-A was additionally modified by dip-coating in poly(dimethylsiloxane) (PDMS) and pyrolyzing to form PDMS-coated cellulose aerogels (Cell-AP) and carbon aerogels (CA), respectively. Results of the oil adsorption tests show that pyrolysis produced aerogels with greater adsorption capacity with an optimal mass ratio of 15 : 1 cellulose to PVA. Furthermore, the pseudo-second-order model was found to be more accurate than the pseudo-first-order model for the study of oil absorption kinetics. As a result, the modified cellulose aerogel is promising for replacing earth-unfriendly polymer-based oil sorbents due to their high oil absorption capacity.

The Impact of Country of Origin on Consumption Intention: A Case Study of COVID-19 Vaccines in Vietnam

Minh Sang VO,Ngoc Phu TRAN,Thi Kieu Thu NGUYEN,Thi Cam Tien HUYNH,Thi Kim Loi NGUYEN,Le Phuong Nghi THACH,Gia Nhu THAI,Thi Thanh Sang TRAN 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.4

This study intends to analyze the impact of the country of origin on the intention to ingest COVID-19 vaccinations by measuring Vietnamese people’s perceptions of India in the manufacture of COVID-19 vaccines. The research is done using a quantitative method, and primary data was obtained using a conventional manner based on the willingness of the research respondents, who are Vietnamese persons aged 18 and up, to contribute information. The findings revealed that perceived brand association and perceived brand quality directly positively impact the COVID-19 vaccine’s consumption intention and willingness. Meanwhile, while the perceived country image component has no direct effect on consumption intention, it does have a positive indirect effect on consumption intention through perceived brand linkage and perceived brand quality. The findings also emphasize the importance and significance of a country’s image in brand association and quality perception. The study’s findings imply that to increase consumers’ willingness to buy India’s COVID-19 vaccination, the country should develop communication initiatives to improve consumer perceptions of the country’s image, the perceived value of the brand association, and brand quality.

A Novel Injectable pH–Temperature Sensitive Hydrogel Containing Chitosan–Insulin Electrosprayed Nanosphere Composite for an Insulin Delivery System in Type I Diabetes Treatment

Thuy An Trinh,Thai Minh Duy Le,Hoang Gia Vinh Ho,Thi Cam Thach To,Vu Viet Linh Nguyen,Dai Phu Huynh,Doo Sung Lee 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1

Faculty of Materials Technology, Ho Chi Minh University of Technology (HCMUT)/Vietnam National University Ho Chi Minh City; ¹School of Chemical Engineering and Theragnostic Macromolecules Research Center, Sungkyunkwan University; ²Vietnam National University Ho Chi Minh City/National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh University of Technology, Vietnam National University; ³Faculty of Materials Technology, Ho Chi Minh University of Technology (HCMUT)/ Vietnam National University Ho Chi Minh City/Research Center for Polymeric Materials, Ho Chi Minh University of Technology, Vietnam National University In this research, a novel insulin composite delivery system was prepared and characterized. Insulin drug was loading in chitoshan nanospheres using electrospraying method, a pH- and temperature-sensitive biodegradable hydrogel, which is an oligomer serine-poly(lactide)-poly(ethylene glycol)-poly (lactide)-oligomer serine (OS-PLA-PEG-PLA-OS) pentablock copolymer was used as a matrix to containing chitosan–insulin electro sprayed nanospheres (CIN). The properties of the OS-PLA-PEG-PLA-OS pentablock copolymer and the chitosan–insulin nanoparticles such as sol-gel transition, degradation in vitro and in vivo were characterized. The results showed that the chitosan–insulin nanospheres uniformly distributed in the matrix had a reinforcing effect on the mechanical properties and prolonged the degradation time of the hydrogel depot under body conditions. In addition, the cytotoxicity experiment results indicate that the composite could be used as a biomaterial for drug delivery system. The composite solutions accommodating different concentrations of the chitosan–insulin nanospheres were subcutaneously injected into induced diabetic BALB/c mice to study the in vivo insulin-release profile. The result showed that insulin concentrations in blood plasma were maintained at a steady-state level. Furthermore, the bio-properties of the insulin were retained and it showed a blood glucose level reducing effect for more than 60 hours after injection to a streptozotocin (STZ)-induced diabetic mouse model. The results suggested that this injectable pH–temperature sensitive hydrogel containing chitosan– insulin electro sprayed nanosphere composites has promising potential applications for type 1 diabetes treatment.