The Late Quaternary Evolution of the Southern Vietnamese Continental Shelf

The late Pleistocene-Holocene sedimentary architecture on two different geological setting areas on the Southern Vietnam Shelf has been investigated on the basis of shallow seismic data, sediment core data, sequence stratigraphic concepts and numerical modeling. The late Pleistocene-Holocene sequence stratigraphic models of the SE Vietnam and Nha Trang Shelf show distinctive features which result from the differences in sediment supply regime, shelf morphology and hydrodynamic conditions between the two areas. Sedimentation on the Nha Trang Shelf from the end of the LGM to present has been investigated on the basis of process-based numerical modeling simulations. The results indicate that the sediment supply during TST period (19.6-8.0 ky BP) is 3 to 4 times higher than that of HST period (8.0-0 ky BP). During HST and TST period, 50-80 % of total supplied sediment was contributed by three local river basins (Cai, Dinh and Van Phong) and the rest was transported alongshore from the north

MINH GIẢI TÀI LIỆU TRỌNG LỰC VÀ TỪ DỰ BÁO CẤU TRÚC TRIỂN VỌNG KHOÁNG SẢN RẮN KHU VỰC THỀM LỤC ĐỊA NAM - ĐÔNG NAM VIỆT NAM

The East Vietnam Sea is a marginal sea with complicated geological structures. The volcanic activities are quite strong after the sea-floor spreading in Cenozoic Era. There are the types of structure here favorable to the formation of solid minerals (manganese-iron aggregation). However, it is difficult to define their ranges and spatial locations. This paper presents the methods of reduction to the magnetic equator in low latitudes to bring out a better correlation between magnetic anomalies and their sources; High-frequency filtering is to separate gravity and magnetic anomalies as well as information about the solid minerals in the upper part of the Earth’s crust; 3D total gradient is to define the spatial location of high density and magnetic bodies. The potential structures of solid mineral are predicted by multi-dimensional correlation analysis between high frequency gravity and magnetic anomalies with weighted 3D total gradient.Biển Đông là một biển rìa có cấu kiến trúc phức tạp, hoạt động phun trào bazan núi lửa xảy ra khá mạnh mẽ ở thời kỳ sau tách giãn đáy. Ở đây, tồn tại các dạng địa hình thuận lợi cho việc hình thành cấu trúc chứa khoáng sản rắn (cụ thể là kết hạch sắt - mangan). Tuy nhiên việc xác định phạm vi, vị trí không gian của chúng gặp nhiều khó khăn bởi lớp nước dày và nguồn tài liệu khảo sát chưa được đầy đủ. Nghiên cứu này áp dụng phương pháp chuyển từ về xích đạo ở vĩ độ thấp nhằm tạo nên mối tương quan tốt hơn giữa dị thường và nguồn gây dị thường Từ; Phương pháp lọc trường tần số cao dùng để phân tách trường Trọng lực, Từ cũng như các thông tin về khoáng sản rắn ở phần trên của vỏ Trái đất; Phương pháp gradient toàn phần 3D xác định vị trí không gian các khối có mật độ, từ tính cao. Cấu trúc triển vọng khoáng sản rắn được dự báo bằng phép phân tích so sánh mối quan hệ đa chiều giữa trường Trọng lực và trường Từ tần số cao với trường trọng số gradient toàn phần 3D của chúng

Damage Detection in Structural Health Monitoring using Hybrid Convolution Neural Network and Recurrent Neural Network

The process of damage identification in Structural Health Monitoring (SHM) gives us a lot of practical information about the current status of the inspected structure. The target of the process is to detect damage status by processing data collected from sensors, followed by identifying the difference between the damaged and the undamaged states. Different machine learning techniques have been applied to attempt to extract features or knowledge from vibration data, however, they need to learn prior knowledge about the factors affecting the structure. In this paper, a novel method of structural damage detection is proposed using convolution neural network and recurrent neural network. A convolution neural network is used to extract deep features while recurrent neural network is trained to learn the long-term historical dependency in time series data. This method with combining two types of features increases discrimination ability when compares with it to deep features only. Finally, the neural network is applied to categorize the time series into two states - undamaged and damaged. The accuracy of the proposed method was tested on a benchmark dataset of Z24-bridge (Switzerland). The result shows that the hybrid method provides a high level of accuracy in damage identification of the tested structure

Studying the thermo-gas-dynamic process in a muzzle brake compensator

To reduce the recoil and improve the stability of small arms, a muzzle brake compensator is attached to the muzzle of the barrel. This device uses the kinetic energy of the powder gas escaping from the bore after the bullet is fired. In this paper, the authors present the determination of the thermo-gas-dynamic model of the operation of a muzzle brake compensator and an example of calculating this type of muzzle device for the AK assault rifle using 7.62x39 mm ammunition. The results of the calculation allowed for obtaining the parameters of the powder gas flow in the process of flowing out of the muzzle device, as well as the change in the momentum of the powder gas's impact on the muzzle device. The model proposed in the article provides the basis for a quantitative evaluation of the effectiveness of using the muzzle device in stabilizing infantry weapons when firing

The role of rice fields, fish ponds and water canals for transmission of fish-borne zoonotic trematodes in aquaculture ponds in Nam Dinh Province, Vietnam

BACKGROUND: Fish-borne zoonotic trematodes (FZT), such as Clonorchis sinensis, Opistorchis viverini (Opisthorchiidae) and intestinal trematodes of the family Heterophyidae, constitute a public health hazard in Vietnam and infections with these trematodes has been linked to consumption of raw or undercooked fish from aquaculture. The FZT transmission pathways, however, are more complicated than just the presence of intermediate snail hosts in aquaculture ponds as ponds may exchange water with surrounding habitats such as rice fields and irrigation canals and thereby these surrounding habitats may be a source of snails and cercariae and contribute to FZT infection in cultured fish. METHODS: This is a longitudinal descriptive study on selected farms (n = 30) in Nam Dinh Province which is endemic for FZT. At each farm, we sampled one pond, a small irrigation canal used to supply the pond with water, and a nearby rice field. At each of these three sites, we estimated the density of the FZT intermediate snail hosts and determined their trematode infection status. Comparative analysis was performed for the prevalence and density of FZT infections in fish and snails. RESULTS: Species of the Thiaridae, and most notably Melanoides tuberculata, the most important host species for FZT belonging to the Heterophyidae, were particularly abundant in ponds and small canals, i.e. M. tuberculata was found in 27 ponds and 13 small canals. Bithynia fuchsiana, a potential host for both Heterophyidae and Opisthorchiidae, was rarely found in fish ponds but common in rice fields. A total of 12 types of cercariae were found in the snails and pleurolophocercous cercariae, primarily FZT, constituted about 40 % of all cercarial infections. The fish species cultured were mainly carp species and Haplorchis pumilio was the dominating trematode species infecting fish. Clonorchis spp. were not recorded in any of the ponds. FZT transmission to fish was intense during the summer period (May-June to November) but less intense during the winter months (December-January) partly because cercarial emergence ceases due to the low temperature. CONCLUSION: Our findings highlight the complexity of FZT transmission within aquaculture farm settings and suggest that efforts to control these infections must take a holistic approach using interventions against all stages of the transmission cycle

Multi-response optimization of process parameters for powder mixed electro-discharge machining according to the surface roughness and surface micro-hardness using Taguchi-TOPSIS

In this study, the efficiency of integration between Taguchi and TOPSIS in multi-response optimi-zation of powder mixed electrical discharge machining (PMEDM) process was evaluated. The in-put parameters, such as workpiece and tool electrode material, polarity, pulse on time (ton), pulse off time (toff), Current (I) and powder concentration have been selected to optimize two responses; namely surface roughness (Ra) and surface hardness (HV). The results show that titanium powder mixed dielectric fluid improves multi-response optimization efficiency in PMEDM. In addition, machining conditions, such as tool electrode material, powder concentration, pulse on time, polarity, current density, A×G and B×G interactions play a very important role on S/N ratio of C* whereby powder concentration has the strongest influence. TOPSIS -Taguchi is a potential method for multi-response optimization in PMEDM. However, the optimal results using ANOVA analysis show that there is a necessity to have more studies in TOPSIS-Taguchi to improve the in-tegration efficiency between two methods for optimizing multiple responses in PMEDM

A Study on Factors Impacting on Profitability: The Case of Vietnam

This study is conducted to investigate factors influencing the profitability of the Vietnamese food processing firms. Data was collected from audited financial statements from listed food processing firms on the Vietnam Stock Exchange. Panel regression model was applied in this study (PLS). The testing methods used in this research were Pearson model; Modified Wald Test, Wooldridge test (for autocorreclation in panel data), Hausman model, especially the relationship between FEM and REM as well as Multicollinearity test based on VIF coeficient. The results shows that DR, SDR and LDR have negative impacts on profitability. In contrast, TDTELT have positive impacts on the profitability. FATA and SIZE impact return on asset (ROA) without statistical significance. SIZE has positive impact on return on equity (ROE) while it impacts negatively on profit margin (PM). Moreover, AGE, GDP growth, and inflation do not have impact on profitability. Keywords: Factors, Return on assets, Food processing firms, Vietnam DOI: 10.7176/RJFA/11-10-07 Publication date:May 31st 202

HORIZONTALLY PLASMON HYBRIDIZATION ON SYMMETRIC-BREAKING METAMATERIALS

In this report, we present a study on the fundamental negative-permeability metamaterials, named as the cut-wire-pair structure. The physics of the cut-wire-pair metamaterial is interpreted using the electromagnetic analog of molecular-orbital theory. It is shown that a symmetric-breaking cut-wire-pair metamaterial is horizontally plasmon-hybridized, leading to an additional magnetic resonance beyond the conventional one. The transmission spectra and the induced energy distributions are performed to demonstrate our prediction

The Role of Serial NT-ProBNP Level in Prognosis and Follow-Up Treatment of Acute Heart Failure after Coronary Artery Bypass Graft Surgery

BACKGROUND: After coronary artery bypass graft (CABG) surgery, heart failure is still major problem. The valuable marker for it is needed. AIM: Evaluating the role of serial NT-proBNP level in prognosis and follow-up treatment of acute heart failure after CABG surgery. METHODS: The prospective, analytic study evaluated 107 patients undergoing CABG surgery at Ho Chi Minh Heart Institute from October 2012 to June 2014. Collecting data was done at pre- and post-operative days with measuring NT-proBNP levels on the day before operation, 2 hours after surgery, every next 24 h until the 5th day, and in case of acute heart failure occurred after surgery. RESULTS: On the first postoperative day (POD1), the NT-proBNP level demonstrated significant value for AHF with the cut-off point = 817.8 pg/mL and AUC = 0.806. On the second and third postoperative day, the AUC value of NT- was 0.753 and 0.751. It was statistically significant in acute heart failure group almost at POD 1 and POD 2 when analyzed by the doses of dobutamine, noradrenaline, and adrenaline (both low doses and normal doses). CONCLUSION: Serial measurement of NT-proBNP level provides useful prognostic and follow-up treatment information in acute heart failure after CABG surgery

Surface sediment grain-size distribution and sediment transport in the subaqueous Mekong Delta, Vietnam

The sediment transport around the Mekong delta was clarified by using geochemical data and modeling indicating the southwestward transport of re-suspended sediments under the influence of NE monsoon. However, the detail pattern of grain-size distribution of the surface sediments in the subaqueous Mekong River delta has not been well understood. This paper presents characteristics of grain-size parameters of the surface sediments in order to interpret the sediment-transport pattern and the linkage to coastal erosion and deposition off the Mekong River delta. Surface sediments collected in the coastal water of Mekong River delta (as far south as Ca Mau Peninsula) were analyzed to determine the grain-size distribution and sediment transports in subaqueous Mekong delta.  Results indicated that the net sediment transport was southwestward to the Ca Mau peninsula and the sediments were finer from the delta topset downward the delta foreset. In contrast, the sediment particles on the adjacent inner shelf were coarser and are more poorly sorted due to the increase in carbonate shell fragments and the Early Holocene sediments. The sediment grain-size parameters were variable in different sedimentary sub-environments of the subaqueous Mekong delta and controlled by the distance of sediment transport, the hydrodynamic regime of each region and coastal erosion of the delta coast.References Anthony J.E., Brunier G., BessetM., Goichot M., Dusouillez P, Nguyen V.L., 2015. Linking repid erosion of the Mekong River delta to human activities. Scientific Reports, 1-12. Blott S.J and Pye K., 2001. Gradistat: a grain size distrubution and statistics package for the analysis of unconsolidated sediments, Technical Communication. Earth Surface Processes and Landforms, 26, 1237-1248. Dung B.V., Schimanski A., Stattegger K., Phach P.V., Tiep N.T., Hai N.T., Thanh N.T., Phi T.T., 2009. 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