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pH buffers of weak organic acids and bases are essential in capillary electrophoresis (CE) analyses, primarily when contactless conductivity detectors (C4D) are used. However, the preparation of a buffer with a known concentration of one component for use as a background electrolyte (BGE) in CE-C4D usually requires a pH adjustment to the desired value and an approximate calculation to estimate the concentration of the second component. This study developed software that allowed determining the concentration of one component when knowing the concentration of another component and the pH of the solution, taking into account the influence of ionic strength. The software was built in C# language with Windows Form interface on Microsoft Visual Studio. With the concentrations calculated from the developed software, the differences (|ΔpH|) between pH values of the obtained BGEs in practice and the desired values were smaller than 0.07, corresponding to the errors of less than 2%.

This study aims to propose a tool for food control activities that can be realizable even with a modest infrastructure, using purpose-made capillary electrophoresis (CE) instrumentation with capacitively coupled contactless conductivity detection (C4D). For demonstration of a featured application, we reported herein a simple and inexpensive method for authentication and quality control of Ophiocordyceps sinensis-based products (literally known as “summer grass, winter worm”). This species, originally found on the Tibetan plateau and in the Himalayas, between elevations of 3000–5000 m, is classified as a medicinal mushroom and has been used as a precious component in traditional Chinese and Vietnamese medicine. Due to its high value and rareness, counterfeit products have emerged, leading to the need for quality control activities. For this purpose, a CE-C4D methodology was developed to determine their adenosine, cordycepin, and inosine contents. These compounds were analyzed on two channels of the purpose-made instrument, with the best-achieved detection limits of 11.2–22.0 μg/g using the developed CE-C4D methods. Cross-checking data using the reference method (HPLC-DAD) was provided to prove the reliability of the analytical results obtained with CE-C4D. Good agreement for the two pairs of data was achieved, with the result deviation being less than 12%.

When a membrane of Nafion swells in water, polymer fibers “unwind” into the adjoining liquid. They extend to a maximum of about ~300 μm. We explore features of Nafion nanostructure in several electrolyte solutions that occur when the swelling is constrained to a cell of size less than a distance of 300 μm. The constraint forces the polymer fibers to abut against the cell windows. The strongly amphiphilic character of the polymer leads to a shear stress field and the expulsion of water from the complex swollen fiber mixture. An air cavity is formed. It is known that Nafion membrane swelling is highly sensitive to small changes in ion concentration and exposure to shaking. Here we probe such changes further by studying the dynamics of the collapse of the induced cavity. Deionized water and aqueous salt solutions were investigated with Fourier IR spectrometry. The characteristic times of collapse differ for water and for the salt solutions. The dynamics of the cavity collapse differs for solutions prepared by via different dilution protocols. These results are surprising. They may have implications for the standardization of pharmaceutical preparation processes.

Two-dimensional models of large spatial domain including Cua Lo and Cua Hoi estuaries in Nghe An province, Vietnam, were established, calibrated, and verified with the observed data of tidal level, wave height, wave period, wave direction, and suspended sediment concentration. The model was then applied to investigate the hydrodynamics, cohesive sediment transport, and the morphodynamics feedbacks between two estuaries. Results reveal opposite patterns of nearshore currents affected by monsoons, which flow from the north to the south during the northeast (NE) monsoon and from the south to the north during the southeast (SE) monsoon. The spectral wave model results indicate that wave climate is the main control of the sediment transport in the study area. In the NE monsoon, sediment from Cua Lo port transported to the south generates the sand bar in the northern bank of the Cua Hoi estuary, while sediment from Cua Hoi cannot be carried to the Cua Lo estuary due to the presence of Hon Ngu Island and Lan Chau headland. As a result, the longshore sediment transport from the Cua Hoi estuary to the Cua Lo estuary is reduced and interrupted. The growth and degradation of the sand bars at the Cua Hoi estuary have a great influence on the stability of the navigation channel to Ben Thuy port as well as flood drainage of Lam River.

Giens double tombolo linking Giens island to the mainland is a unique geomorphological formation in the world. However, its existence has been threatened by coastal erosion, especially in the eastern part of this tombolo. The investigation of historical shoreline changes along the eastern Giens tombolo were carried out applying the integration of satellite remote sensing and geographic information system (GIS) techniques. Additionally, the combination of the Digital Shoreline Analysis System (DSAS) and linear regression method was used to predict the location of future shorelines. The results obtained from the analysis of shoreline position showed that the average annual change rate along the eastern Giens tombolo varied around +0.18 m/yr during the duration from 1973 to 2015, revealing a general progradation trend. Even though accretion is dominant, there are some local areas undergoing severe erosion. The most severely vulnerable areas were Les Cabanes du Gapeau, the south of Ceinturon, Pesquiers, and the north of La Capte with the maximum change rates of −1.05 m/yr, −0.77 m/yr, −0.44 m/yr, and −0.29 m/yr, respectively. The change analysis of shorelines in 2020 and 2050 also reveals these severely eroded areas. On the other hand, this work demonstrates that both natural factors and human activities are the main causes of the shoreline changes in the eastern Giens tombolo.

This paper presents a design of multi-layer wideband 3 dB 180o hybrid coupler based on tapered coupled-line structure. The design is fully implemented on a four-layer printed circuit board. The transition between tightly coupled lines and uncoupled lines is fully characterized and laid out to ensure impedance and field matching. As a result, the proposed coupler obtains a return loss better than 15 dB, an insertion loss better than 4 dB, an isolation better than 20 dB, an amplitude imbalance within ±1dB, and a phase imbalance within ± 5o over the range of 8 to 18 GHz. The hybrid coupler is designed to cover the X band Ku bands (8 – 18 GHz), utilized as balun for wideband antennas.

Beaches along the eastern branch of the Giens double tombolo are subject to coastal erosion. Prediction of the behavior of the beach profile configuration in response to natural and anthropogenic changes using the concept of equilibrium beach profile (EBP) could be useful in finding the most suitable measure to address the erosion problem. Field investigation data of 11 beaches along the eastern tombolo were supplied for this study, and a nonlinear fitting technique was applied to estimate the best parameter values of seven empirical formulations of the relevant EBP. All of the observed beach profiles could be described by a single function, but a single EBP was inadequate to represent all of the beach profiles observed. The variation found could be explained in terms of longshore variation of bathymetry, sediment size, and wave parameters. Analysis of the validity of the EBPs revealed that a representative EBP of each beach is governed by different equilibrium parameters.

This study reported a simple and inexpensive method for determination of 10-hydroxy-2-decenoic acid (10-HDA) and free amino acids in different royal jelly based dietary supplement samples using a purpose-made dual-channeled capillary electrophoresis (CE) system with capacitively coupled contactless conductivity detection (C4D). The objective of the work is to propose a tool for food / quality control activities that can be realizable even with a modest infrastructure. 10-HDA and free amino acids were analyzed using the background electrolyte (BGE) solutions composed of 20 mM Tris(hydroxymethyl)aminomethane adjusted to pH8.5 with acetic acid and of 2 M lactic acid, respectively. The best achieved detection limit for 10-HDA was 0.039 mg/g and those for free amino acids were in ranged of 0.039–0.090 mg/g using the developed CE-C4D methods. Good agreement between results obtained from CE-C4D and those with the standard confirmation methods (HPLC-PDA) was achieved, with the result deviation for the two pairs of data being less than 5 % for 10-HDA and 16 % for free amino acids.

In this study is reported a simple and inexpensive method for concurrent determination of taurine and choline in different supplementary nutrient samples using dual-channeled capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (C4D). The objective of the work is to propose a tool for food control activities that allows screening of different target compounds (having different characteristics) in a single run for high throughput and can be realizable even with modest infrastructure. Taurine was analyzed in the first CE channel using the background electrolyte (BGE) composed of 150 mM tris(hydroxymethyl)aminomethane/lactic acid (pH 8.96) whereas choline was simultaneously separated in the second CE channel using a BGE containing 150 mM tris(hydroxymethyl)aminomethane/acetic acid (pH 9.5). The best achieved detection limit was 0.27 mg/L and 0.45 mg/L for taurine and choline, respectively, using the developed CE-C4D method. Good agreement between results obtained from CE-C4D and those with the standard confirmation methods (HPLC-DAD for taurine and LC/MS for choline) was achieved, with the result deviation for the two pairs of data being less than 12%.

In this paper, we propose a multi-objective approach for generating sets of feasible trade-off solutions for the Vietnamese anti-spam system (using SpamAssassin). The two objectives for considering are the Spam Detection Rate (SDR) and False Alarm Rate (FAR).The experiments were conducted based on Vietnamese spam data set through three scenarioswith different numbers of SpamAssassin rules; and we used the non-dominated sorting genetic algorithm(version 2) - NSGA-II for finding the trade-off solutions. The result of each scenario was recorded to compare with the performance of the traditional approach (single objective optimization).According to the statistical results, the new approach not only achieved more efficient results but also created a set of ready-to-use rule scores which supports different levels of the trade-off between SDR and FAR.

In this paper, four spam-filtering approaches based on the mail networks: Clustering, Extended Clustering Coefficient, PageRank Algorithm and Weighted PageRank Algorithm are analyzed. We also propose a couple of fully worked-out datasets against which the experimental comparisons with the respect to the accuracy of email user ranking and spam filtering are conducted. The results indicate that PageRank algorithm and Extended Clustering Coefficient approaches are better than others. The rate of true detection is over 99.5% while the failed alarm remains below 0.5%.

To give autonomous mobile robots some kind of "social intelligence", they need to be able to recognize and interact with other agents in the world. This paper describes how a light signaling device can be used to identify another individual and to communicate simple information. By having the agents relatively close to each other, they share the same perceptual space, which allows them to sense or deduce implicit information concerning the context of their interaction. Using a vision- and sonar-based Pioneer I robot equipped with a colored-light signaling device, experimental results demonstrate how the robot. can interact with a human interlocutor in a ball-passing game.