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Water hyacinth (Eichhornia crassipes) is a wild floating plant that can be found widely in pond or river areas. The plant grows fiercely and causes many harmful issues to the ecosystem around its covered area. This work provides a utilization method that converts wild water hyacinth to reliable magnetic biochar which can be used as a very effective adsorbent for the removal of lead ion Pb(II) in industrial wastewater. The mentioned magnetic biochar can be prepared via a modified pyrolysis process at 550°C with the support of cobalt sulfates as magnetite precursors and limited oxygen from the sweeping gas (the gas mixture ratio is 4 : 1 nitrogen/oxygen). The produced samples were hydrophobic biochar with high oxygen-containing functional groups that are suitable for the removal of inorganic contaminants. The impregnation of cobalt (II, III) oxides provided high magnetic separation performance and additional adsorption sites on the produced magnetic biochar. As indicated by the obtained result, the WHB-Co2M sample possesses a highly porous structure (0.126 cc/g), higher thermal stability (thermal durability reaches 900°C), relatively stable magnetic properties (14.74 emu/g), and a larger surface area (192 m2/g). These beneficial properties led to its suitability to serve as an adsorbent in removing lead ions in the contaminated effluent, recording 95% of removal efficiency and adsorption capacity of 67.815 mg/g. As indicated in the result, all prepared magnetic biochar samples were fitted to two-parameter (Langmuir models) and three-parameter (Sips model) isotherm models. Therefore, the adsorption process in this work could be carried out on both homogeneous and heterogeneous adsorbent surfaces. The adsorption kinetics of the removal process also was described by the pseudo-first-order, pseudo-second-order, and Elovich models to reveal the adsorption and desorption rate of the as-prepared magnetic biochar. This work indicates a successful waste refinery route of converting lignocellulosic biomass such as water hyacinth into value-added material for use as promising heavy metal adsorbents.

Total artificial heart is associated with increased incidence of thromboembolism, which can prove to be fatal. The presence of four metallic tilting discs increases the chances of thrombus formation and sudden obstruction of the valve in a closed position resulting in severe hemodynamic collapse. Such a condition is conventionally treated by a surgical approach for device change; however, this procedure is extremely high risk and associated with complications and poor outcomes. We describe two total artificial heart patients with sudden obstruction to the filling of the right side due to fixing of the atrioventricular valve in a closed position due to a thrombus. After a quick diagnosis by rescue transesophageal echocardiography, we successfully treated these patients with catheter-directed thrombolysis with minimal adverse outcomes. We propose a carefully weighed application of this approach in hemodynamically unstable patients too tenuous for a timely surgery and with low risk for bleeding.

Vegetables have been shown to be able to provide nutrients, including vitamins, minerals and especially fiber, and release toxins that arise during the digestion of food. As a result, the importance of vegetables has been increasingly emphasized in the human diet. In this study, Kohlrabi, a vitamin C-rich vegetable, was used for lactic fermentation. The whole process was optimized by varying a wide range of parameters including concentrations of salt solution and pH value on the growth of lactic acid bacteria, product texture and sensory characteristics. Current results revealed the optimal conditions for the fermentation process are as follows: NaCl solution used of 3.5%, initial pH 4.2, and MnCl2 with a concentration of 30 mM. The obtained Kohlrabi pickle products exhibited acceptable quality and good sensory scores after 2 days. Elevated temperature was also found to be associated with loss of hardness, quality loss and longer fermentation time. Optimized Kohlrabi pickling process will contribute to diversifying pickled vegetable products to avoid the defects caused by improper processing.

The outdoor radon (222Rn) and thoron (220Rn) concentrations at 320 dwelling points at 1m above the ground in different locations surrounding rare earth elements (REE) and uranium mines in Northern, Vietnam were measured using the RAD7 equipment. Results showed that the 222Rn was always higher than 220Rn concentration with a range from 25.7 to 573 Bq/m3 and from 18.5 to 385 Bq/m3, respectively. In general, the 222Rn and 220Rn concentration showed a large variation, especially in the study location of the NX-Lai Chau. The highest 222Rn and 220Rn concentration was found in this location as well. The 222Rn and 220Rn activities surrounding the REE mines were found to be higher than those surrounding the uranium mines. The average value of annual committed effective doses originated from the inhalation of 222Rn and 220Rn outdoor dwellings is about five times higher than the worldwide average value as reported in UNSCEAR (2000).

A series of recent studies have shown that permissionless blockchain peer-to-peer networks can be partitioned at low cost (e.g., only a few thousand bots are needed), stealthily (e.g., no control plane detection is available), or at scale (e.g., the entire bitcoin network can be divided into two). In this paper, we focus on the sustainability of partitioning attacks in Bitcoin, which is barely discussed in the literature. Existing studies investigate new partitioning attack strategies extensively but not how long the partition they create lasts. Our findings show that, fortunately for Bitcoin, the permissionless peer-to-peer network can be partitioned but only for a short time. In particular, two recent partitioning attacks (i.e., Erebus, SyncAttack) do not maintain partitions for more than 10 minutes in most cases. After analyzing Bitcoin’s peer eviction mechanism (which makes the two original attacks difficult to sustain), we propose optimization strategies for the two attacks and calculate the total cost of the optimized attacks for a 1-hour attack duration. Our results complement the original attack studies: (i) the optimized Erebus attack shows that it requires at least one adversary-controlled Bitcoin node close to a target and a few additional expensive attack steps for sustainable attacks, and (ii) the optimized SyncAttack can create sustainable partitions only with excessive cost., Financial Cryptography and Data Security: 27th International Conference, FC 2023

Thorough understanding of kinetics plays a key role in improving existing industrial processes. In this study, we attempted to model the kinetics of the hydro-distillation process that produces essential oil from peels of pomelo (Citrus grandis L.) fruit, which is a product with high economic value and a wide range of applications. We first determined the optimal water-to-material ratio for attaining maximal oil yield. Then, further experimental attempts were carried out at different distillation rates to generate experimental data to fit three kinetic models, namely first-order kinetics model, instantaneous washing, followed by diffusion model and simultaneous washing and diffusion model. Overall, the three models have well described the experimental kinetic data on hydro-distillation (R2> 90%). Of which, the simultaneous washing and diffusion model attaining the R2 of 99.97% was chosen as the most suitable to describe the kinetics of the extraction process. Estimated parameters also shown that the washing stage occurs more rapidly than the later, diffusion stage. GC-MS results showed that the obtained oil sample was characterized by the dominance of the D-Limonene compound (97.873%).

Bưởi là loài cây không chỉ có giá trị cao về mặt dinh dưỡng mà còn có giá trị cao về mặt kinh tế và được trồng phổ biến ở Việt Nam. Ngoài ra, tinh dầu bưởi chứa nhiều hợp chất có hoạt tính sinh học cao. Tinh dầu bưởi được chiết xuất bằng phương pháp chưng cất lôi cuốn hơi nước và thành phần hóa học được phân tích bằng phương pháp GC-MS. Thành phần chính của tinh dầu gồm limonene (91,19%), b-myrcene (2,92%), a-phellandrene (1,98%) và a-pinene (1,19%). Hoạt tính kháng vi sinh vật của tinh dầu được khảo sát với vi khuẩn Gram dương (Bacillus cereus, Staphylococcus aureus), Gram âm (Escherichia coli) và nấm mốc Aspergillus flavus ở nồng độ 5, 10, 25 và 50% bằng phương pháp khuếch tán giếng thạch. Tinh dầu có khả năng kháng B. cereus, S. aureus và E. coli với đường kính vòng kháng khuẩn lần lượt là 8,3–11,3, 10,3–18,7 và 9,0–11,7 mm và ức chế sự phát triển của A. flavus (18,9–65,0%).

The 2H/1H and 18O/16O isotope ratios in rainwater bring a lot of information about the fractionation of water molecules in the hydrosphere. The relationship between the isotope ratios of rainwater in an area characterised by the local meteoric water line, which is known as a reliable reference value for studies related to the identification of the recharge source of groundwater and climate change investigations. This study aims to establish a local meteoric water line in Long Khanh city (LK LMWL) in the period of 2020-2021, which is considered as a basis for research on the origin of groundwater in the area of Long Khanh city and subsequent studies on the origin of groundwater in the Southeast of the Mekong Delta region and the Dong Nai river basin. Results show that δ2H in rainwater ranges from -73.64 to 0.36 (‰ VSMOW) with an average value of -49.74‰ (n=19) and that figure of δ18O ranges from -10.91 to -1.59 (‰ VSMOW) with a mean of -7.68‰ (n=19). Due to the amount and specific meteorological conditions of the region, δ2H and δ18O in rainwater are enriched in the dry season but deplete in the rainy season. The LK LMWL follows a model of δ2H=(7.89±0.38)xδ18O + (10.28±2.93) (R2=0.96, n=19), which shows that the isotopic composition of δ18O in rainwater is more enriched than the isotopic composition of δ2H. The deuterium excess (d-excess) of rainwater in the region is found to be 10.28±2.93‰, which is comparable to those for the global scale of 10‰.

In this paper, we present some ideas and methods to create new problems of proving inequalities, problems of finding maximum and minimum values. Based on the maximum and minimum properties and tangent inequalities of convex and concave functions, we propose some ideas and methods to create new problems. We make all ideas and methods to be real via many specific functions. Especially, we combine the ideas and methods with equivalent transforms, Cauchy-Schwarz inequality, and inequality of arithmetic and geometric means to create new hard problems. New proposed examples, they have showed that our ideas and methods are important and efficient to lecturers at high schools and universities in giving questions in examinations, especially in examinations of selecting good students at levels, in Olympic examinations for high school and university students.

The goal of this research is to evaluate the influence of the polyphenols extract of Polygonum multiflorum Thunb. root on the lipid oxidation, chemical properties and sensory characteristics of ground beef during frozen storage. Beef was ground in aqueous solutions of polyphenols extract at different concentrations: 830, 415, 277, 208 and 166 mg GAE/L, polyphenols solution/sample ratio is 1/20 (v/w). Then, the ground beef was stored for up to 100 days at -20±2oC. The best oxidation inhibitor for ground beef was at the highest polyphenols concentration of 830 mg GAE/L. All quality parameters (pH, PoV, MDA, color parameter and sensory evaluation) of the treated sample and of the control sample display significant differences during storage period. For this reason, it was concluded that the polyphenols extract of Polygonum multiflorum Thunb. root could be used as an alternative source of natural antioxidant in beef processing.

Introduction: The metabolites of lichens concentrated depsidones, depsides, and diphenyl ethers were possessed antibiotic, antifungal, antiviral, antitumor, and anticancer activities. Parmotrema tinctorum (Despr. ex Nyl.) Hale, a species of foliose lichen, is widely distributed in Lam Dong province, Vietnam. Herein, this paper describes the isolation and structure elucidation of seven compounds isolated from this lichen. Methods: Phytochemical investigations of the ethyl acetate extract of the lichen P. tinctorum led to the isolation of seven pure compounds. Their chemical structures were elucidated by extensive HR-ESI-MS and NMR spectroscopic analysis and comparison with previously published data. Results: Seven compounds, namely orcinol (1), orsellinic acid (2), methyl orsellinate (3), methyl heamatomate (4), lecanorin (5), lecanoric acid (6), and gyrophoric acid (7). These compounds were determined the α-glucosidase inhibitory activity. Conclusions: Compound 7 was determined for the first time in P. tinctorum, and this was also the first time these compounds were determined the α-glucosidase inhibitory activity.

This work addresses the problem of extended-dissipative finite-time reliable control of switched stochastic model with non-deterministic actuator faults, time-delay, sampled-data scheme, saturation nonlinearity and stochastic uncertainties, where the actuator faults obey certain probabilistic distribution. The important of this article is to develop a stochastic fault-tolerant sampled-data controller under actuator saturation nonlinearity such that the considered stochastic switched model is stochastically stable and obeys a dissipative pursuance ratio in the finite-time interval. A novel finite-time criteria are proposed to guaranteeing the stochastically stable in finite time for switched stochastic system based on the finite-time stability theory and suitable Lyapunov–Krasovskii functional (LKF) along with convex integral inequality method. Then, the derived criteria are presented in terms of linear matrix inequalities (LMIs) and it can be solved efficiently by standard Matlab software. Finally, numerical simulations are given to illustrate the efficiency of the proposed method.

Introduction: Axial-flow and centrifugal-flow left ventricular assist devices (LVAD) have been utilized in the management of heart failure, but it remains unknown whether these devices differ in end-organ perfusion. Our goal was to evaluate the association between device type and regional cerebral oxygen saturation (rSO2), and determine if this confers any benefit in short-term postoperative outcomes. Methods: Adult patients who underwent primary LVAD implantation at our institution from 2014 to 2019 were retrospectively analyzed. Patients were stratified into axial-flow and centrifugal-flow groups. Intraoperative rSO2 readings were used to calculate the change in mean rSO2 from pre- to post-bypass. Multivariable modeling was performed to compare delta rSO2 between groups, and to analyze the association between LVAD type and postoperative outcomes. Results: There were 152 patients included, of which 76 had an axial-flow device and 76 had a centrifugal-flow device implanted. The rSO2 level increased from pre-bypass to post-bypass on average 3.5% (CI: 2.1 to 5.0) for the axial group compared to 0.1% (CI: −1.2 to 1.4) for the centrifugal group, which was a significant difference (β = −2.22, CI: −4.21 to −0.32, p = 0.022). Axial devices approached significance for lower odds of postoperative complications (OR: 0.35, CI: 0.11 to 1.06, p = 0.063), and were associated with significantly shorter ICU LOS (β = −0.36, CI: −0.60 to −0.11, p = 0.004). Conclusion: Axial devices resulted in a greater increase in rSO2 than centrifugal pumps after separation from CPB. Further investigation is warranted to evaluate the effect of LVAD selection on long-term end-organ perfusion and subsequent patient outcomes.

The presence of volcanic materials in reservoir will reduce the porosity value and effect to the quality of reservoirs. Therefore, understanding the distribution of this object will be of great significance in the orientation of oil and gas exploration and exploitation. This paper applies seismic attribute analysis method combined with artificial neural network (ANN) application to predict the distribution of volcanic materials in D sequence. Attributes selected as input for ANN training including RMS, RAI and Specdecom attribute. The results indicate that volcanic materials mainly appear in the to the Southwest of block (around D well and the West of E well), a small part is scattered near Con Son swell. The correlation coefficient among seismic attribute is from 71 to ~ 80%, this shows that the reliability of the results of network training is relatively high. Therefore, this method can be used to predict the distribution of volcanic materials in the study area.

Chemical investigation of the lichen Usnea ceratina Arch led to the isolation of five depsidones, including one new compound ceratinalone (1) along with four known compounds bailesidone (2), stictic acid (3), 8'-O-methylstictic acid (4) and 8'-O-ethylstictic acid (5). The structures were determined by analysis of their MS and NMR data as well as by comparison with literature values. Compounds 1 and 4 were evaluated the cytotoxic activity against HeLa (human epithelial carcinoma), NCI-H460 (human lung cancer), HepG2 (liver hepatocellular carcinoma), and MCF-7 (human breast cancer) cell lines, showing the moderate activity.

In this work, we study systematically low-energy bands, optical absorbance and spin/valley-Hall conductivity of silicene and germanene in the presence of a perpendicular electric field. Our analytical calculations indicate that both silicene and germanene are semiconductors with a tiny energy gap and we can control their energy gap by the perpendicular electric field. Our calculations also demonstrate that the low-frequency optical absorbance of silicene is much greater than that of germanene and the external electric field plays an important role in determining the optical absorption peaks. When the Fermi level is in the forbidden band, the Hall conductivity is quantized, while spin/valley-Hall conductivities of both silicene and germanene depend strongly on the Fermi energy when the Fermi level is in the conduction band. Analytical results for spin/valley-Hall conductivities of silicene and germanene are presented in detail in this work.

In this paper, we study the ill-posed fractional backward heat equation $$ \left\{\begin{array}{ll} \frac{\partial^{\gamma} u}{\partial t^{\gamma}}={\varDelta} u,\quad x\in \mathbb{R}^{n},t\in(0,T),\\ u(x,T)=\varphi(x), \quad x\in\mathbb{R}^{n}, \end{array}\right. $$ where φ is unknown exact data and only noisy data φe with $$ \|\varphi^{\varepsilon}(\cdot)-\varphi(\cdot)\|_{L_{2}(\mathbb{R}^{n})}\leqslant\varepsilon $$ is available. The problem is regularized by the well-posed mollified problem $$ \left\{\begin{array}{ll} \frac{\partial^{\gamma} v^{\nu}}{\partial t^{\gamma}}={\varDelta} v^{\nu},\quad x\in \mathbb{R}^{n},t\in(0,T),\\ v^{\nu}(x,T)=S_{\nu}(\varphi^{\varepsilon}(x)), \quad x\in \mathbb{R}^{n}, \end{array}\right. $$ where ν > 0 and Sν(φe(x)), a mollification of φe defined by the convolution of φe(x) with Dirichlet kernel. The error estimates $\|u(\cdot ,t)-v^{\nu }(\cdot ,t)\|_{H^{l}(\mathbb {R}^{n})}, 0\leq l$ are established for ν chosen a priori and a posteriori.

We consider a general ill-posed inverse problem in a Hilbert space setting by minimizing a misfit functional coupling with a multi-penalty regularization for stabilization. For solving this minimization problem, we investigate two proximal algorithms with stepsize controls: a proximal fixed point algorithm and an alternating proximal algorithm. We prove the decrease of the objective functional and the convergence of both update schemes to a stationary point under mild conditions on the stepsizes. These algorithms are then applied to the sparse and non-negative matrix factorization problems. Based on a priori information of non-negativity and sparsity of the exact solution, the problem is regularized by corresponding terms. In both cases, the implementation of our proposed algorithms is straight-forward since the evaluation of the proximal operators in these problems can be done explicitly. Finally, we test the proposed algorithms for the non-negative sparse matrix factorization problem with both simulated and real-world data and discuss reconstruction performance, convergence, as well as achieved sparsity.

In the current market economy, it is important to evaluate and forecast the situation and business performance of enterprises to provide the necessary information for managers to plan for future us...

Citrus peel extract has been observed with many beneficial-promoting effects. Pomelo (Citrus grandis (L) Osbeck) peel extracts (PPE) from the flavedo and albedo of two varieties namely Long Co Co and Thanh Kieu were investigated. In this study, the qualitative analysis indicated the presence of phytochemical groups including alkaloids, flavonoids, saponins, and tannin in the PPE from the flavedo and albedo. The PPE from the Thanh Kieu flavedo was found to possess the highest antioxidant activity at the EC50 values of 60.89 ± 0.31 µg/mL, 60.69 ± 0.21 µg/mL, and 24.16±0.06 µg/mL for DPPH, ABTS, and FRAP assay. However, the Long Co Co albedo- PPE induced better inhibitory effect against α-amylase (EC 232-560-9) and α-glucosidase (EC 232-604-7) with respect to EC50 values of 3.59 ± 0.02 mg/mL and 80.77 ± 0.34 µg/mL. This result suggested potential in the anti-hyperglycemic effect of pomelo peel extract from the flavedo and albedo that can serve as a nutraceutical in food and pharmaceutical industries.

Mango (Mangifera indica L.) is a widely consumed fruit in tropical/subtropical regions around the world due to its excellent flavor and taste, and valuable source of nutrients and phytochemical compounds. As a climacteric fruit, mango is easily perishable after harvesting due to the ripening process, environmental conditions, and improper postharvest handling, leading to significant quality losses as well as economic loss throughout a supply chain. Postharvest losses are attributed to harvesting at an improper maturity stage, poor postharvest pretreatment, improper packing and packaging, inappropriate storage temperature and distribution conditions. These caused mechanical damage, sap burn, spongy tissue, weight loss, fruit softening, decay, chilling injury, and postharvest diseases. Currently, each step in the supply chain has been applied many postharvest technologies to reduce the quality losses of mango fruits as well as improving their marketability with the highest retention of quality. This review documented available possible causes for the quality losses and observed the physicochemical changes of mango fruit when applying postharvest technologies at each critical step in the mango supply chain from harvesting, pre-treatment, packaging, storage, to distribution. The summarized information is expected to provide comprehensive quality changes of mango fruits and point out the proper technology at each step of the supply chain.

Microencapsulation technique helps to protect the core materials from deterioration, thereby improving the bioavailability of active compounds. In microencapsulation, the wall properties determine the encapsulation efficiency, and better results can be achieved when a mixture of multiple wall materials is used. This study aimed to optimize the wall material composition of pomelo peel (Citrus maxima (Burn.) Merr.) microcapsules prepared by spray drying technology to achieve the best values of polyphenol recovery and encapsulation efficiency. Response surface methodology was employed and a Box-Behnken design was used to investigate the effects of four independent variables, including the concentrations of resistant maltodextrin, pectin, β-cyclodextrin, and gum arabic. The concentration of the feeding liquid, and spray drying inlet and outlet temperatures were fixed at 30 °Bx, 180 °C, and 65 °C, respectively. The results showed that the optimized wall material composition consisted of 52.66% maltodextrin, 0.92% pectin, 5.30% β-cyclodextrin, and 6.28% gum arabic. Using this formula, the polyphenol recovery yield was found to be 78.86%, while the encapsulation efficiency was 77.78%, which agreed well with the predicted values of 78.90% and 77.67%. These results strongly indicate that the optimized wall material composition proposed in this study may be beneficial in the encapsulation process.

A class of optimal control problems governed by linear fractional diffusion equation with control constraint is considered. We first establish some results on the existence of strong solution to the state equation and the existence of optimal solutions for the optimal control problem. Then we derive first-and second-order optimality conditions for locally optimal solutions to the problem.

We consider a multiscale elliptic eigenvalue problem that depends on n separable microscopic scales. Using multiscale homogenization, we derive the multiscale homogenized eigenvalue problem whose solution contains all the possible eigenvalues and eigenfunctions of the homogenized eigenvalue problem. We develop the sparse tensor product finite element (FE) method for solving this multiscale homogenized problem, thus bypassing the expensive task of forming the homogenized equation. Although the multiscale homogenized eigenvalue problem is posed in a high dimensional tensorized domain, the sparse tensor product FEs achieve a prescribed level of accuracy requiring an essentially optimal number of degrees of freedom which differs from the optimal one by only a possible logarithmic multiplying factor, given that the solution to this problem is sufficiently regular. We show that the regularity requirement is achieved under the Lipschitz condition on the multiscale coefficient. Numerical examples on two- and three-scale eigenvalue problems support the theoretical error estimates.

This paper analyzes the impact of base erosion and profit shifting (BEPS)on tax revenue in Southeast Asian countries for the period of 2012-2017. ASEAN countries are mostly developing countries with little experience dealing with the aggressive tax strategies of multinational corporations (MNEs). Accordingly, measuring the impact of BEPS on tax revenue in Southeast Asian countries is essential and urgent. Specifically, this paper measures BEPS by offshore index using the Offshore Investment Matrix approach proposed by UNCTAD (2015). According to this approach, 3.6% of inflow foreign direct investment in six Southeast Asian countries for the period of 2012-2017 originated from tax havens and specialpurpose tax countries. The empirical simulation shows that about $ 2.195 billion of the tax revenue of Southeast Asian countries in2017 is lost because of BEPS.

This study attempted the extraction of essential oils from the peels of pomelo (Citrus grandis L.) grown in Ben Tre province, Vietnam through hydrodistillation method. In addition, the chemical composition and physio-chemical properties of the essential oils were reported. The results showed that the extraction yield of the extraction process achieved about 1.67%. The physico-chemical index of essential oils is determined by specific gravity (0.8572 g/cm3), acid index (0.3556 mg KOH/g), ester index (2.4216 mg KOH/g), and refractive index (1.476). The GC-MS analyses of the oil indicated the component with highest content in the oil was α-limonene (96.491%), followed by α-pinene (0.686%), β-pinene (0.248%), β-myrcene (1.644%), α-phellandrene (0.793%) and β-cis-ocimene (0.138%). These results suggested that wastes from fruit peeling process can be converted into a new material source with great potential for industrial use.

This study aimed to identify phytochemicals and evaluate antioxidant activities of different extracts from Eucalyptus camaldulensis, an aromatic plant in the Myrtaceace family. Examined extracts in different solvents such as diethyl ether extract (DEE), the ethanolic extract (EE) and the aqueous extract (AE). Total polyphenol and total flavonoid contents were determined via aluminum chloride colorimetric method. Antioxidant activity was performed via ABTS and DPPH radical scavenging assays. The results showed that a wide variety of pharmacologically active compounds such as alkaloid, oil, flavonoid, triterpenoid, saponin, tannin and polyphenol were present in the leaves of Eucalyptus camaldulensis. The result of quantitative determination showed that total polyphenol content of the diethyl ether extract, ethanolic extract and aqueous extract achieved 73.47 ± 1.64, 306.48 ± 3.87 and 76.47 ± 1.64 mgGAE/g, respectively. Meanwhile, total flavonoid content was 41.74 ± 2.21, 45.98 ± 1.79 and 18.05 ± 0.81 mgQE/g, respectively. The ethanolic extract exhibited the highest DPPH (IC50 = 10.52 ± 0.14 μg/mL) and ABTS (IC50 = 9.86 ± 0.17 μg/mL). These results indicate that Eucalyptus camaldulensis leaves can be used in dietary applications with the potential to reduce oxidative stress.

Study on kinetics and modeling of the essential oil steam distillation are required for the optimization of the energy requirement, parameters and the process scale-up. In this study, hydrodistillation for extraction of essential oils from lemongrass (Cymbopogon citratus) steam distillation was investigated. The recovery of essential oils was carried out on an industrial scale instrument and with with different material quantities. The experimental results are determined by the integral method of analysis. The kinetic parameters were evaluated from experimental data, which were generated at the different weights of the lemongrass. The extraction rate constant explaining the extraction efficiency achieved from this study is found to be k2 of 0.0661 min-1 in 710 kg using a second-order kinetic model. The GC/MS results revealed that 14 components were identified in Cymbopogon citratusoils. The oil is extremely rich in citral (69.775%), which obtained in 180 min.

The objective of this study was to determine the optimal value of factors affecting the extraction of phenolic compounds from sugar apple seeds. The effects of solvent nature (ethanol, methanol and water), solvent concentration (40, 60,80 and 100%), solid-to-solvent ratio (2.5/100, 5.0/100, 7.5/100 and 10 mg/100 mL ), extraction temperature ( 40, 50, 60 and 70 ºC ) and extraction time (60, 120, 180 and 240 min) were investigated. Total phenolic content and total flavonoid content were used for the determination of phenolic compounds of sugar apple seeds extract. Experimental results showed that all the examined parameters had statistically significant (p < 0.05) effects on phenolic compound extraction. The optimal extraction conditions were as follows: extracting solvent 80% ethanol, sample-to-solvent ratio 5 g/100 mL, extraction contact time 120 min and extraction temperature 60 ºC with values of 356.92 ± 9.27 mgGAE/100g DW, 240.03 ± 6.16 mgQE/100g DW for the total phenolic content and the total flavonoid content, respectively.

This study attempted the optimization of the extraction process involving essential oils from Vietnamese pomelo fruits. Three influential parameters including ratio of water and material, extraction time, and temperature were assumed to be impactful to the oil yield and were investigated by establishing a statistical model. A central composite design was adopted to generate dataset required for estimation of the model. Analysis of variance was used to calculate model significance. The results showed that optimum yield of pomelo oil is 4.46 % (v/w) corresponding to water ratio of 507 mL water to 100 g sample, temperature at 119.29 ºC and distillation time of 113.68 min. Predicted values proposed by the Design Expert 11 software well-agreed with the empirical data, suggesting the excellent predictability of the proposed models. In addition, the essential oil obtained under optimal conditions was analyzed by gas chromatography-mass spectrometry. The results indicated that D-limonene is the main component (97.318 %) of essential oil.

Gomphrena celosioides Mart. is well known for its medicinal values worldwide. In this study, three extracts, viz. diethyl ether extract (DEE), ethanolic extract (EE) and aqueous extract (AE), were successively obtained from the leaves and stem of Gomphrena celosioides to determine the polyphenol and flavonoid content in this plant. A wide variety of pharmacologically active compounds such as alkaloid, flavonoid, terpenoid, saponin, tannin and polyphenol compounds were present in Gomphrena celosioides. The results of quantitative determination showed that total polyphenol content of DEE, EE and AE reached 35.35 ± 1.47, 250.17 ± 2.95 and 133.92 ± 3.17 mgGAE/g, respectively. Moreover, total flavonoid content of the DEE, EE and AE was 23.21 ± 1.87, 50.74 ± 2.32 and 27.25 ± 1.34 mgQE/g, respectively. In comparison with DEE and AE, the ethanolic extract exhibited the highest DPPH (IC50 = 13.29 ± 0.10 μg/mL) and ABTS (IC50 = 6.3 ± 0.11 μg/mL).

The dissociation point is the condition where three phases of hydrate (H), liquid water (Lw), and vapor (V) coexist. This is the thermodynamic phase equilibrium property and is essential to the exploration and utilization of new energy sources of methane hydrates. Additive compounds are usually used in methane hydrate research. The measurements of the dissociation conditions or the three-phase (H-Lw-V) equilibrium temperatures and pressures are required for ternary mixtures with additives. The dissociation points of the methane hydrate mixture in the presence of each additive of (0.10 to 0.30 mass fraction) acetamide, (0.05 and 0.08 mass fraction) cyclopentanol, and (0.10 and 0.20 mass fraction) 1,3-dioxane in aqueous solutions were experimentally measured in this study. To simulate the seawater condition, the dissociation points of these additives in brine solution were also investigated. The isochoric method with an apparatus operated at high-pressure and low-temperature conditions was applied. New expe...