Sintering behavior and physical properties of Bi0.5(Na1–xKx)0.5SnO3 lead-free ceramics

In this study, Bi0.5(Na1–xKx)0.5SnO3 (BNKS) ceramics (x = 0, 0.1, 0.2, 0.3, and 0.4) were fabricated via ultrasound wave before milling. The time of ball milling decreased from 20 to 1 h. The X-ray diffraction patterns show that the BNKS has a single-phase structure. When the potassium content increases, the phase structure of the ceramics changes from rhombohedral to tetragonal. When sintered at 1100 °C and x = 0.2, the ceramics’ physical properties are the best with the mass density of 5.59 g/cm3, the electromechanical coupling constants kp of 0,31 and kt of 0.27, the remanent polarization of      11.9 µC/cm; the dielectric constant εr of 1131, and the highest dielectric constant emax of 4800

NGHIÊN CỨU VI SINH VẬT SỐNG CÙNG MỘT SỐ LOÀI SAN HÔ CỨNG TẠI HANG RÁI NINH THUẬN BẰNG PHƯƠNG PHÁP NHUỘM HUỲNH QUANG KẾT HỢP NUÔI CẤY TỚI HẠN

Coral associated bacteria and their host are currently one of the interested issues for research and scientists worldwide. The densities of zooxanthellae and bacteria associated with three most prevalent species Acropora hyacinthus, Acropora muricata and Acropora robusta in Hang Rai, Ninh Thuan was evaluated over time by staining with SYBR Gold and direct counting with epifluorescence method. The most dominant bacteria were isolated by culture dependent method. The densities of zooxanthellae and bacteria ranged from 0.39–1.83×107 cell/g, and 0.83–2.52×108 cell/g, respectively. Bacterial density in the 3 months was significantly different compared to the density of the bacteria in ambient water. Total heterotrophic bacteria, comma shaped bacteria and bacillus form showed negatively correlated with pH, PO4, while zooxanthellae showed no correlation with all factors.Rạn san hô trên toàn thế đang đối mặt với sự huỷ diệt nghiêm trọng, một trong những nguyên nhân chính là do vi khuẩn gây bệnh và những tác động của môi trường. Chính vì vậy, nghiên cứu về hệ vi khuẩn sống cùng san hô và mối tương quan giừa vi khuẩn, san hô và các yếu tố môi trường là quan trọng và cấp thiết. Trong nghiên cứu này, mật độ vi tảo Symbiodinium sp., vi khuẩn sống cùng 3 loài san hô cứng Acropora hyacinthus, Acropora muricata và Acropora robusta phổ biến tại Ninh Thuận được đánh giá vào các thời điểm trước, trong, và sau khi san hô bị tẩy trắng bằng phương pháp đếm huỳnh quang và pha loãng tới hạn. Kết quả cho thấy mật độ tảo Symbiodinium khác nhau có ý nghĩa thống kê (dao động 0,39-1,83x107tb/g) ở các loài san hô khác nhau. Tuy nhiên, mật độ tảo cộng sinh không có khác biệt lớn giữa các tháng nghiên cứu. Mật độ vi khuẩn dao động từ 0,83-2,52x108tb/g và có sự sai khác có ý nghĩa thống kê không chỉ giữa các loài san hô mà còn ở các thời điểm trước trong và sau tẩy trắng. Tổng vi khuẩn, phẩy khuẩn và trực khuẩn có tương quan nghịch và có ý nghĩa về mặt thống kê với chỉ số pH và hàm lượng PO4. Ngược lại, mật độ tảo hoàn toàn không tương quan với các yếu tố môi trường

Financial crisis and diversification strategies: The impact on bank risk, and performance

This paper explores the impacts of asset, funding, and income diversification strategies and their combinations on the banking system’s performance and risk in Vietnam. Dynamic models, using two-step difference-GMM with panel data collected from 34 Vietnamese commercial banks from 2005 to 2019, are employed. Results indicate that, in general, diversification practices in banking sectors are effective in improving banks’ risk-return profile, especially during the Vietnamese banking crisis from 2011 to 2014. However, using them in combinations is only effective for income and funding diversifications. These results are robust regarding the use of alternative measures of diversification level. Based on the findings, managers and government agencies in the Vietnamese banking sectors could be informed about the diversification strategy effectiveness to aid their strategic decisions on operations, investments, and financing

Mucilage Extracted from Dragon Fruit Peel (Hylocereus undatus) as Flocculant for Treatment of Dye Wastewater by Coagulation and Flocculation Process

Dye wastewater from textile industries shows very low biodegradability due to high molecular weight and complex structures of dyes. So far, the most simple method for treatment of this type of wastewater has been coagulation and flocculation. This study determined the removal of turbidity and other pollutants from dye wastewater by mucilage extracted from the peel of dragon fruit (Hylocereus undatus) and its effect in reducing synthetic chemical polyaluminum chloride (PACl) used in coagulation and flocculation (CF) process. The removal of turbidity in a sequent CF process using PACl and dragon fruit mucilage was investigated based on Jar tests. Maximum coagulation efficiencies of PACl were typically observed at pH 4.0-6.0 and PACl concentrations of about 100-150 mg/L depending on types of wastewater, whereas optimal settling times were 30-60 minutes, respectively. The addition of dragon fruit mucilage (0.5-50 mg/L) after PACl (75-245 mg/L) resulted in turbidity removal efficiencies up to 95%. The addition of mucilage extracted from dragon fruit peels was proven to increase turbidity removal efficiency and decrease PACl use. The increase of turbidity removal was often estimated at 10-32%, whereas PACl used was about 3-10% less compared to total PACl needed for obtaining comparable efficiency when used alone. The flocculation activity of mucilage was also compared to polyacrylamide (PAM)—a synthetically organic flocculant. Since the peel of a dragon fruit is an abundant agriculture waste in Vietnam, using its extracted mucilage as a flocculant is an environmentally friendly method

Can traders help farmers transition towards more sustainable maize based farming systems? Evidence from the Lao-Vietnamese border

Intensive maize cultivation in the uplands of North-west Vietnam has resulted in soil erosion leading to reduced maize yields along with negative impacts downstream. Despite the introduction of sustainable agricultural technologies over many years, adoption rates are low mostly due to their incompatibility with existing farming systems and lack of secure markets for alternative crops. In addition, the temporary nature of development programmes and limited capacity of government extension systems have resulted in limited spread of technology, and where they have been introduced, unable to secure long-lasting commitments from farmers. In this study, we explore an alternative model involving maize value chain actors for attaining more durable transition towards sustainable maize farming systems. We find maize traders operating at lower levels of the value chain with active engagement with the farming community to be best suited for engaging in technology dissemination. While their involvement may require additional incentives and oversight from the government it is imperative that support for commercialization through promising market links are established to achieve a more meaningful shift towards sustainable farming methods

Effect of the Optimize Heart Failure Care Program on clinical and patient outcomes – The pilot implementation in Vietnam

Background: The Ho-Chi-Minh-city Heart Institute in Vietnam took part in the Optimize Heart Failure (OHF) Care Program, designed to improve outcomes following heart failure (HF) hospitalization by increasing patient awareness and optimizing HF treatment. Methods: HF patients hospitalized with left ventricular ejection-fraction (LVEF) <50% were included. Patients received guideline-recommended HF treatment and education. Clinical signs, treatments and outcomes were assessed at admission, discharge, 2 and 6 months (M2, M6). Patients' knowledge and practice were assessed at M6 by telephone survey. Results: 257 patients were included. Between admission and M2 and M6, heart rate decreased significantly, and clinical symptoms improved significantly. LVEF increased significantly from admission to M6. 85% to 99% of patients received education. At M6, 45% to 78% of patients acquired knowledge and adhered to practice regarding diet, exercise, weight control, and detection of worsening symptoms. High use of renin-angiotensin-aldosterone-system inhibitors (91%), mineralocorticoid-receptor-antagonists (77%) and diuretics (85%) was noted at discharge. Beta-blocker and ivabradine use was less frequent at discharge but increased significantly at M6 (from 33% to 51% and from 9% to 20%, respectively, p < 0.001). There were no in-hospital deaths. Readmission rates at 30 and 60 days after discharge were 8.3% and 12.5%, respectively. Mortality rates at 30 days, 60 days and 6 months were 1.2%, 2.5% and 6.4%, respectively. Conclusions: The OHF Care Program could be implemented in Vietnam without difficulty and was associated with high usage of guideline-recommended drug therapy. Although education was delivered, patient knowledge and practice could be further improved at M6 after discharge. Keywords: Heart failure, Optimize, Education, Knowledge, Mortality, Readmissio