Optical wireless communication is a potential candidate for 5th generation wireless communication systems (5G). The technology is orientated towards a commercial product called LiFi. This is technology for high-speed transmission and is especially effective in applications of Internet of Things (IoT). In order to evaluate the transmission quality of optical wireless systems, the wireless optical channel needs to be simulated through mathematical equations. The popular simulation methods of optical channel nowadays need to take many operations, particularly in the multiple-input and multiple-output (MIMO). In this paper, the response of the MIMO optical wireless communication and methods to reduce the number of operations in determining response of MIMO optical wireless channel were studied. Analysis results show that this method was reduced four times the complexity in 2x2 MIMO antenna configuration with reflection factor of 2.

In modern society, production and usage of plastic become popular; however, this creates a huge of plastic waste, which seriously causes damage to the environment. This study aims to test applicability of plastic waste to produce concrete to help reduce the flow of plastic waste into dump. The mixed concrete samples were prepared with cement, sand, water and plastic for testing of compressive strength, in which the plastic was applied as a replacement material for sand. The testing results show that optimum ratio for replacement plastic to sand was 5 - 30%. At this range, the testing concrete received good compressive strength compared to the control sample. Beside that, the cost for preparing the plastic to concrete production was high. Therefore, it is necessary to improve the preparation step to reduce the cost.

Assessing the slope stability is extremely complicated and risky. There are many unexpected and unforeseen incidents occurring during the project’s operation and usage phase. This may be caused by several reasons including inappropriate computational models, inadequate collected data and the unsustainability of soil physical properties. Among these causes, the unsustainability of soil physical properties plays a significant role because it determines the sub-grade stability. The role of this factor is showed clearly in the case of projects carried in adverse conditions. This paper presents the method used to assess the roadbed slopes stability in the landslide areas in which physical properties of soil has changed significantly, by adopting the reliability theory though using Monte Carlo simulation model. The input parameters of this method are random variables following a standard normal distribution. This research will provide the objective point of view regarding assessment of the roadbed slope stability to all practitioners.

Schedule delays occur frequently in construction projects around the world and Vietnam; it probably leads to damages, impacts on financial matters and even causes myriad disputes in litigation among project parties. Hence, many delay analysis techniques have been proposed and used for analyzing schedule delay problems, namely the real-time delay, concurrent delay, pacing delay, acceleration schedule, float ownership and its consumption, resource allocation and productivity loss. However, no universal technique can solve all complex project situations and is widely accepted by project participants due to the inability of existing approaches to address thoroughly all aforementioned delay issues. This paper examines current delay analysis techniques by applying a real case study to identify which is the most ideal technique to give a reliable and an accurate result that can ensure a greatly acceptable outcome in resolving delay claims. Study results revealed that currently ideal technique is still necessary improved because of its shortcomings. Further researches may also develop an effective approach in full compliance with professional softwares that can solve all identified delay schedule-related problems.

This study is aimed to find a solution to using super-capacitors for generating solar energy instead of using batteries; the supercapacitor serves low-power applications such as lights, warning lights, power supplies for environmental monitoring electronic devices industrial sensors on dangerous places or replace motorcycle’s batteries, etc. The super-capacitors have high advantages strength, friendly environmental, capacity energy storage in short time. The study sets up some experiments for charging by positive balancing methods appling on six super-capacitors 350F/2.7VDC, which generates by solar panels 12VDC/25W. Experimental results demonstrated that using super-capacitors to replace batteries in storing solar energy is completely feasible.

The available graphite rod was employed as a cathode for removing p-nitrophenol in a cathode electro-Fenton process using a simple DC power supply. The effects of the operational parameters such as cell potential, electrolytic time and concentration of ferric ion were investigated. The results showed that the reduction of oxygen to H2O2 on the graphite cathode was initiated at the cell potential higher than 4.0 V. Additionally, the reduction of ferric ion to ferrous ion was much favorable when the applied cell potential was higher than 1.0 V. Increasing the surface area of the graphite cathode also enhanced the electro-chemical reduction of ferric ion. Removal rate of p-nitrophenol was greater than 90% after 120 minutes at pH 3 using the undivided electrochemical cell. Therefore, the electro-Fenton is a promising process for the treatment of organic pollutants in water without using any harmful chemicals.

This paper is aimed to build a suitable SCADA system for data collection, monitoring and control for low voltage networks in agencies, companies. Important parameters of an electrical network are updated in real time and stored for analyzing and evaluating the system.  The flexible SCADA model is built with a self-built measuring station on processor/ microcontroller platform using kit NI myRIO, 02 measuring stations using multifunction measurement equipment Mishubishi ME96NSR and a program for management on LabVIEW. The model system can display the parameters of the electric network almost in real time, store the parameters over time, demonstrating the feasibility of the proposed solution. This paper contribute to designing solution and building an automatic monitoring system for important parameters in the low voltage networks. This work helps the electrical network woking safety-savings and reducing labor effort that bring significant efficiency for agencies and companies.

The article refers to the characteristics of the land surface temperature extracted from the Landsat image from which to consider changes in the formation of surface urban heat island for the Northern part of Ho Chi Minh city, excluding Nha Be and Can Gio. Time survey included 3 times of image acquisition in 1995, 2005 and 2015. Research has identified surface urban heat island from thermal infrared band, according to the ability of the surface emission based on characteristics of normalized difference vegetation index (NDVI). The results showed a growing trend of temperature fluctuations over the city and a gradual expansion of the high-temerature zone towrds the suburbs. In the period 1995-2015, the trend of the formation of surface urban heat island with 4 typical locations showed a clear difference between the surface temperature of urban areas and rural areas and a quadruple spatial expansion of heat island in 2015 compared to 1995. Since then, solutions to reducing the impact of urban heat island were proposed in order to protect the urban environment and the lives of residents in Ho Chi Minh City.

This study was conducted on two lab-scale high rate Spirulina sp. algae culture pond which operated at hydraulic retention time (HRT) of 3 days and 5 days, to evaluate the effectiveness of reducing organic matter, reusing nutrients in biogas effluent and producing algal biomass. Biogas effluent was settled for 30 minutes, then diluted with tap water at a ratio of 1 : 1 (v/v) to reduce the concentration of pollutants and color before loaded to the algae ponds. At HRT of 5 days, the results showed that the concentration of BOD5, COD, TKN, TP, N-NH4+, and total Coliform in the effluent (after harvesting algal biomass) decreased by 73.78%, 74.07%, 95.71%, 83.08%, 99.4%, and » 100%. For HRT of 3 days, BOD5, COD, TKN, TP, N-NH4+ and total Coliform reduced by 61.76%, 61.78%, 95.13%, 67.43%, 98.45%, and » 100%. The concentrations of BOD5, COD and TP in the effluent of two ponds were significantly different (5%), while the concentrations of TKN, N-NH4+ and total Coliforms were not significantly different (5%). In terms of biomass, the concentration of Chlorophyll content in ponds with HRT of 5 days was 2369.18 ± 436.52 mg/L, higher than that (1078.68 ± 320.53 mg/L) of the pond having HRT of 3 days  (p

Three compounds including (1) lupeol acetate, (2) 1-palmitoylglycerol and (3) tricin were isolated from the hexane and ethyl acetate extracts of Vernonia cinerea (L.) Less. Their structures were interpreted by spectroscopic methods such as 1H-NMR,13C-NMR, HSQC, HMBC, MS and based on published data. Total polyphenolic content showed the ethyl acetate extract (215.55 mg GAE /g extract) was higher than ethanol and aqueous extracts. These results correlated with the highest DPPH scavenging capacity of ethyl acetate extract, IC50 = 24.10 mg/mL.

The aims of this study were to identify the species composition of Euglenophyta in Dong Thap Muoi ecological sanctuary – Tien Giang province and build the image gallery of these determined species. Besides, the results of this study can be used as a reference about Euglenophyta biodiversity for further research. Samplings were performed at ten sites within the ecological sanctuary in September 2015 and February 2016. Seventy-one species belonged to five genera were identified within this area. The genus Phacus was the most dominant genus with 27 species (38.03%), followed by Trachelomonas (18 species, 25.35%) and Euglena (14 species, 19.72%). Lepocinclis and Strombomonas had the same number of species, each with 6 species (8.45%). Noticeably, although Euglenophyta species appeared in all sampling sites, their distributions were significantly different among these sites. The highest number of species was recorded at site D06 (22 species). Samples taken from site D05 in the first survey and site D03 in the second survey also had high diversity of Euglenophyta, with 21 and 20 species, respectively. In contrast, only 2 species were identified from samples taken in site D02 of each sampling time. The numbers of species determined in the first and second surveys were similar, with 47 and 51 species, respectively. There were 27 species present in both two surveys.

In this paper, a sequence of equilibrium problems in metric space is considered. Sufficient conditions for the sequence of approximating problems converging in the sense of Wijsman to the original problem are studied. In addition, concepts of sequentially (generalized) Tykhonov well-posedness under perturbations by a sequence of approximating problems are proposed, then sufficient conditions for such properties are established.

A one-step synthetic pathway of N-(3-morpholinopropyl)benzimidazole has been developed including in situ reduction/cyclization of N-alkyl-o-nitroanilines and aldehydes using Na2S2O4 as the reducing agent. Based on this method, ten new N-(3-morpholinopropyl)benzimidazole derivatives have been successfully synthesized in moderate to excellent yields (42-91%). The structures of these new compounds were fully confirmed by various spectroscopic methods such as MS, IR, 1H-NMR and 13C-NMR.

This article presents the classification methods and calculable problems in their real application. The article also proposes an algorithm to determine the prior probability in classifying by Bayesian method that is better than existing ones. The application from real data in appraising ability to repay loans of customers is performed by all methods to illustrate for theories and to examine logic of the establishsed algorithm. This application also shows that the proposed approach is more advantage than others and it can be applied for many other domains.

In this paper, we study the model of random walk with state space . We use the method of moments as in Depauw et al.’s paper (2009) and Lam Hoang Chuong’s paper (2014) to prove that this random walk conveges in distribution to a normal law (Theorem 1.3) and give its rate also (Theorem 3.1). More precisely, with  be the corresponding Markov operator of the previous random walk and a given function f, we solve the Poisson equation and then treat the limits of its solutions, the rate of the convergence is instantly given by the convergence of the moment of random walk.

An experiment was carried out to determine the effect of dietary organic acid mixture (Poulacid) supplementation to commercial diet on performance and egg quality of laying hens from 19-28 weeks of age split into 2 periods: 19-21 and 22-28). Five hundred and forty Hisex Brown laying hens at the early of laying age were randomly distributed in a completely randomized design experiment, with 3 treatments and 45 replicates (each replicate consisting of 4 birds/pen). Diet treatments include (i) A0: basal feed + 0% Poulacid (control), (ii) A0.15: basal feed + 0.15 % Poulacid, and (iii) A0.2: basal feed + 0.2% Poulacid. The results revealed, there was no effect on feed intake and egg weight, but a little improvement in hen day production and feed conversion ratio in 0.15% diets compare to the control and 0.2 % groups. The 0.15 and 0.2% Poulacid supplement diet showed lower proportion of broken, unnormal and double york eggs compared with the control group. There was no significant effect of treatments on egg shape index, shell weight, shell thickness, albumen weight, Haugh Unit, yolk weight. But there was a light improvement of albumin index and yolk color in supplemented groups compared with the control group. The conclusion of this experiment is that adding poulacid product at 0.15% could lightly improve hen day production and feed conversion ratio, but not egg quality of commercial laying hens.

In this study, several factors including callus treatment, light regimes during co-cultivation period and using mannose as the selective agent in regeneration medium were investigated for the transformation in japonica rice variety Taipei 309. Proliferated calli derived from the embryo scutella were inoculated with Agrobacterium tumefaciens carrying the vector containing a gene encoding phosphomannose isomerase (PMI). Only transformed cells were capable of utilizing mannose as a carbon source and callus induction frequency on selection medium RO5 was used to evaluate the gene transfer efficiency. The results indicated that the increase of gene transfer efficiency in wounded calli (7.3%) as compared to intact calli (3.7%). In co-cultivation period, the best result was obtained (9.3%) when callus was cocultured under continuous light regime. Shoot regeneration from transformed calli was 100% and 15.6% in medium RO6 and medium RO6 + 2% mannose, respectively. Similarity, the shoot proliferation rate was 97.8% and 11.1% in medium RO7 and medium RO7 + 1.5% mannose, respectively. A chlorophenol red (CPR) assay was used to confirm the activity of PMI gene, 100% of putative transgenic rice plants gave positive result. The presence of PMI gene was also evaluated by Polymerase Chain Reaction (PCR) analysis, the expected 600bp fragment for the PMI gene was amplified from these putative transgenic rice plants.

Different maturities of marian plum (Bouea macrophylla) grown at Binh Minh district, Vinh Long province to their physico–chemical properties from 21 to 57 days after anthesis were studied. The results showed that color changed from green to organe, indicated by the the decrease in L* values and the increase in a* values which b* values in the peels increased during harvest date. Fruit weight and fruit size increased from 21 to 42 days and insignificantly decreased from 42 to 57 days, while fruit flesh percentage was highest from 37 to 50 days and decrease afterward. The increase of total soluble solids (TSS) content and decrease of titratable acid (TA), following by the increase of TSS/TA ratio was noticed during harvest date. Vitamin C content decreased from 21 to 42 days and increased from 42 to 57 days. The growth of marian plum can be divided into 2 stages: development (≤42 days) and maturity 42 ÷57 days); overmature stage was not identified in the experiment.

The study was conducted to make high nutritional hamburger with lotus seed added for consumers’more choices. Impact of lotus seeds additional rate, incubation conditions (quantity of yeast, temperature and time) and baking temperature to physical properties and sensory value of hamburger were studied. Results showed that lotus seed hamburger had golden-brown color, good volume and texture with adding of 10% lotus seeds, 1.6% yeast and fermented at 38oC for 110 minutes. The cake had golden-brown color and soft structure when baking was carried out at 210oC. The study results demonstrated that lotus seeds contribute to enhancing the nutritional value and creating unique flavor for lotus seed hamburger.

The study was conducted to evaluate development potentials of AG-Nep variety in An Giang province, based on data collected from interviews of 150 households and 12 local officers. The analytical hierarchy process (AHP) was used to analyse factors that could influence on this glutinous rice production, including seeding rate, amount of fertilizers, production costs, soil erosion and market-linking capacity. The results showed that glutinous rice cultivation with AG-Nep variety has been main agricultural production strategy of Phu Tan district (occupied 92% of toatl growing area) and it contributed to high income (17-13 million dong/ha/crop).  AG-Nep had high developemnt potential index (P=5.26) in Phu Tan district, however, high seeding rates (>240kg/ha) and high amount of fertilizers (151-221kg/ha) were major influential factors in production. To increase the potential index and income for the farmer, the following factors should be considered: suitable seeding rates (120kg/ha), balance of fertilizers amount (100-120Nkg/ha) and manage irrigation water. Bisides, Improving soil fertile and linking up  the market should be concerned. This study can provide information for planning and developing AG-Nep in An Giang province.

Pineapple has been cultivated in Tân Phước, Tiền Giang for more than 6 years and fertilizers application depends highly on local farmers' experiences. In addition, organic fertilizers has not been often used. These reasons could probably lead to the soil degradation resulting in the low yield and inhomogeneous products. Therefore, soil properties assessment is important to understand possible factors leading to the low yield of pineapple in the area. Different soil samples were taken according to different land preparation methods: (1) raised beds were renewed and new crops were introduced; (2) raised beds were not renewed over the last 6 years (each crop per year); and (3) raised beds which are recently not cultivated pineapple due to the infection of many diseases in previous years resulting in very low yield. Results showed that soil samples collected from the first group of land preparation methods have got better chemical properties, e.g., organic matter and CEC are significantly higher than those in second (unimproved soils) and third groups (uncultivated soils). Hence, soil in these beds need to be newly prepared and replanted to improve soil nutrients content. In addition, results of this study showed that the P in the complex compounds with Fe- was dominant compared to Al- and Ca-P compounds, in all three groups of soils. It is necessary to apply organic fertilizer and lime, and phosphate- fertilizers to increase concentration of available phosphorus and to reduce iron and aluminum toxicity.

Isolating and screening promising bacteriophages for controlling bacterial wiltonmarigold caused by Ralstonia solanacearum in the laboratory and screen house condition stoscreen bacteriophages expressed high effec tinmanagement bacterial wilt disease. Total 38 bacteriophages and 21 strains ofR. Solanacearum were isolated from infected plant and soilsamples in provinces of Can Tho, Hau Giang, An Giang, Tien Giang and Dong Thap. Testing lytic ability of these phages on 21 strains of R. solanacearum, tenphages showed effective parasitizing of many strains ofR. solanacearum(15-16strains) i.e.phages ΦCT18, ΦĐT3 and ΦĐT4 showed potentially in lysing of bacterial lawn with diameter of plaque 6.09 mm, 5.88 mm and 7.99 mm respectively at 72 hours after inoculation. In the screenhouse, soil drenching with one of three phages ΦCT18, ΦĐT3, ΦĐT4 alone or either mixture of three phages at density 108PFU/mlfor controlling bacterial wilt onmarigold, the result showed that phage ΦĐT4 expressed good disease protection.

The aim of this study is to describe actiwihtvities of some digestive enzymes of snakehead larvae from day 1 to day 35 after hatching, feeding with two different diets. In the first treatment, larvae were fed with live feed including Moina sp. and marine trash fish; in the second treatment, larvae were still fed with live feed, but live feed was gradually replacement by formulated diet from day 17 onwards. Larvae were sampled at 1; 3; 5; 7; 9; 12; 15; 18; 21; 25; 30 and 35 days after hatching (DAH), before feeding in the morning. The result showed that, amylase enzymes activity fluctuated during the research period and reached 3.68±0.17 mU/mg protein in live feed treatment and 5.77±0.14 mU/mg protein in formulated diet treatment at 35 DAH. Proteolytic enzymes were detected at low level as early as hatching and remained constant until 12 DAH. Trypsin activity increased significantly at 21 DAH. The highest pepsin activity was 1.44±0.26 mU/mg protein, recorded at 25 DAH, and the highest trypsin and chymotrypsin activities were 333±19.9 mU/mg protein and 1,773±62.3 mU/mg protein respectively, at 35 DAH. Pepsin and trypsin activities of larvae feeding with live feed were significantly higher than those fed formulated diet. However, the higer α-amylase activity was found in larve fed formulated diet treatment.

This study was conducted from May to December 2015 to evaluate the technical and economic aspects of mixed gillnet fisheries in Tra Vinh province. It was interviewed with 45 households using mixed gillnet with main contents such as number of boats, fishing season, fishing grounds, yields and financial performance. Results showed that the number of mixed gillnet boats was 80 boats for 26.4% total gill net vessels accounting in Tra Vinh. Mixed gillnet vessels with average capacity of 253.77 CV/vessel and average tonnage 33.5 tons/vessel. The average yield was 16 tons/vessel/year. The total average costs of a fishing trip were 28.49 million VND and net return was 23.93 million VND/fishing trip, benefit ratio was 0.87. No mixed gillnet fishermen had been losses. Difficulties of mixed gillnet fisheries were the initial investment cost was high, consumer product market instability, lack of funds and product preservation techniques.

This study is aimed to determine the appropriate method for elaborating of single cell detritus (SCD) from red seaweed (Gracilaria tenuistipitata) and to assess the effects of SCD as feed on growth and survival of Artemia franciscana- one filter feeder species. Three SCD products including SCD-N, SCD-L, SCD-Y were elaborated with the process: Step 1) seaweed powder was immersed in freshwater, shaked well during 2 hours; Step 2) non-fermented and fermented with Lactobacillus acidophilus (SCD-L) or yeast Saccharomyces cerevisiae (SCD-Y) for 72 h; Step 3) separated by filtering through 50 µm mesh size. The densities of SCD-N, SCD-L and SCD-Y are 77.7 ± 4.7 × 104; 165 ± 10.0×104 and 301 ± 30.6×104 particles/mL, respectively. Artemia were fed by 7 feeding regimes, shrimp feed was considered as the control diet, the others were 6 food regimes in which shrimp feed was replaced by SCD-N, SCD-L, or SCD-Y, with percentage of 50% and 100%. Results showed that diet with 100% SCD-Y or a combination of 50% SCD and 50% shrimp food presented the relatively high survival rate, good growth performance of Artemia, as well as a positive influence on the maturity of A. franciscana.

Alginate is liner polysaccharides extracted from brown seaweed. It is a co-polymer composed of (1® 4)-β-D-mannuronic acid and α-L-guluronic acid. In this paper, the effects of technological factors such as pH value of sodium carbonate solution, temperature and time during the alkaline extraction step on alginate yield and viscosity of the alginate were studied. The results showed that the best conditions for alkaline extraction alginate from brown seaweed residue Turbinaria ornata were determined at pH value of sodium carbonate solution 11, temperature 59oC for 1.5 hours. The maximum alginate content and viscosity were 32.15% dry weight algae and 743 mPa.s, respectively.

The study is aimed to investigate the appropriate C/N ratio for the best growth and survival of black tiger shrimp larvae and postlarvae. The experiment included four treatments of molasses supplement with different C/N ratios as (i) C/N = 10:1, (ii) C/N = 20:1, (iii) C/N = 30:1 and (iv) no molasses addition (control). Experimental tank volume was 120 liters, filled with water at salinity of 30 ‰. Stocking density was 150 larvae/liter. After 25 days of rearing the results of the experiment showed that TAN and NO2- in the treatments have biofloc always lower and significant statistically (p 0.05). Vibrio bacterial density in the treatment C/N = 20:1 and C/N = 30:1 was not harmful to the development of shrimps. The highest postlarvae 15 (PL-15) growth rate was found in treatment C/N = 30:1 and it was significant difference compared to remaining treatments (p

The study is aimed to determine the effect of carrot (Daucus carota) supplementary as feed for white leg shrimp (Litopenaeus vannamei) on their growth and shrimp quality of white leg shrimp (Litopenaeus vannamei). The experiment was randomly set up with four treatments at different amounts of carrot addition including (i) 100% commercial pellet, (ii) commercial pellet in combination with 10% carrot addition, (iii) 20% carrot addition, and (iv) 30% carrot addition. Shrimps were cultured in biofloc system (C: N = 15: 1) at stocking density of 150 shrimp/m3 and water salinity of 15‰. The initial shrimp weight was 0.37±0.09 g (3.49±0.32 cm in length). After 60 days of culture, final shrimp weight in control treatment (no carrot addition; 8.95 g/shrimp) was significantly smaller than those of 10 and 30% carrot addition treatments (9.25 and 9.33 g, respectively). Survival rate and shrimp biomass in 20% and 10% carrot addition treatments (62,2% and 61.5%; 0,86 and 0.85 kg/m3, respectively) were significantly higher than those of 30% carrot addition and control treatments. The increase in addition of carrot increased shrimp sensory property, especially shrimp color. There was no significant difference in shrimp proximate composition among treatments. Results indicated that, 10% carrot supplement as feed for white leg shrimp under biofloc condition enhanced growth rate, survival rate, shrimp biomass, shrimp color and feed cost.

Research on the effect of replacing Artemia by formulated feed on growth, survival rate of mud crab larva was done in order to reduce the feed cost. The experiment was randomly setup with 4 treatments: (i) 2 Artificial feed + 6 Artemia; (ii) 3 Artificial feed + 5 Artemia; (iii) 4 Artificial feed + 4 Artemia, and (iv) 5 Artificial feed + 3 Artemia. Each treatment was triplicated. Experimental tanks were 0.5 m3. Stocking density was 300 individuals/L and salinity water was 30‰. After 12 days of rearing, all larvae reached the zoae 4 stage, larvae were transferred to tanks (2m3,1,5m3 water) and survival rate was from 58.0 to 74.7%, but there was no statistically significant difference between treatments (p>0.05). After 21 days, crab conversion rate in all treatments was 100% and the growth rate of the crabs was not significantly different among treatments (p> 0.05). However, the highest survival rate from zoea 1 to crab 1 was found in treatments fed 3 times formulated feed combined with 5 times fed Artemia a day (7.8%) and it was statistically significant difference compared to other treatments (p

This paper reviews current knowledge on fish broodstock nutrition, aiming at updating understandings on nutritional requirement of broodfish, which is useful for culture and development of broodfish diets. Gonad development and fecundity of fish depend on a number of individual essential nutrients in feed. Improving nutrition in broodfish feed shows positive effects on the quality of reproduction, larval and juvenile fish. Numbers of studies have focused on identifying nutrient demands for broodfish in relation to reproductive performance of some commercially farmed fish species. The sufficient nutrients in broodsfish feed play a decisive role in improving the quality of fish reproduction and were identified as protein, essential amino acids, lipids, polyunsaturated fatty acids, vitamins, carotenoids and minerals. In addition, nutritive source and feeding ration also affect spwaning performance of fish and their off-spring.