STUDY ON APPLICABILITY OF THE CONTACT OXIDATION PROCESS IN REMOVAL OF ORGANIC POLLUTANTS FROM TEXTILE WASTEWATER

Joint Research on Environmental Science and Technology for the Eart

Estimation of forest Carbon Stocks in Ba Be National Park, Bac Kan province, Vietnam

Climate change and an increase in the greenhouse effect are a matter of global concern. One of reasons for this phenomenon is the increase in greenhouse gases, especially CO2. Therefore, the authors investigated CO2 absorption from forests of 45 plots in Ba Be National Park, characterized by 3 forest states as rich, medium and poor forest, rehabilitated forest after exploitation to estimate carbon sequestration of the forest. In which, the carbon stock of rich forest reaches 273.17 tones/ha, the medium forest is 136.23 tones/ha and the poor forest, rehabilitated forest is 42.06 tones/ha. With a forest growth rate of 1.8% per year, the carbon sequestration in Ba Be National Park for 3 forest states is about 16,499 tones per year. This will contribute to improve environmental quality, reducing greenhouse gas emissions and creating a scientific basis for managers to develop a payment mechanism of forest carbon sequestration services

Ammonia oxidation capacity of bacillus bacteria in swine wastewater after biogas treatment

Nitrogen removal with biological methods plays a crucial role in wastewater treatment technology. The treatment begins with the oxidation of ammonia to nitrite to facilitate the subsequent nitrification and denitrification. Various strains of ammonia-oxidising bacteria have been reported. In this study, we use three Bacillus bacteria isolated from swine wastewater to oxidise ammonia. Different initial densities (103, 104, 105, and 106 CFU·mL–1) of each strain were examined. The results show that the combination of all the bacteria at a ratio of 1:1:1 and a density of 105 CFU·mL–1 exhibits the most effect. The findings contribute to the diversity of ammonia-oxidising bacterial species and pose a great potential for applying these strains in wastewater treatment

Nitrite metabolism of several bacterial strains isolated from abattoir and swine wastewater after biogas treatment

In nitrogen treatment with biological methods, nitrite metabolism is an intermediate process that facilitates other processes involving different bacteria strains. In this study, we isolated two nitrite-oxidising bacteria strains from abattoir wastewater and wastewater from biogas tanks of an industrial pig farm in Ha Tinh province. The bacteria strains grow, develop, and metabolise nitrite at pH 6–8 and 30–37 °C. The samples with the nitrite concentration up to 750 mg·L–1 were oxidised within four days of incubation, and the nitrite metabolism rate was proportional to the concentration of nitrite tested. Under severe conditions (salinity up to 3% NaCl, a low dissolved oxygen level of 0.1 mg·L–1), the two isolated bacterial strains exhibited their effective growth and nitrite metabolism capacity. The results enrich the database of nitrite-oxidising bacteria and are prospective in wastewater treatment

NeCo@ALQAC 2023: Legal Domain Knowledge Acquisition for Low-Resource Languages through Data Enrichment

In recent years, natural language processing has gained significant popularity in various sectors, including the legal domain. This paper presents NeCo Team's solutions to the Vietnamese text processing tasks provided in the Automated Legal Question Answering Competition 2023 (ALQAC 2023), focusing on legal domain knowledge acquisition for low-resource languages through data enrichment. Our methods for the legal document retrieval task employ a combination of similarity ranking and deep learning models, while for the second task, which requires extracting an answer from a relevant legal article in response to a question, we propose a range of adaptive techniques to handle different question types. Our approaches achieve outstanding results on both tasks of the competition, demonstrating the potential benefits and effectiveness of question answering systems in the legal field, particularly for low-resource languages.Comment: ISAILD@KSE 202

Pulse-width modulation direct torque control induction motor drive with Kalman filter

The paper deals with application of Kalman filter in induction motor drive using pulse-width modulation direct torque control (PWM-DTC). In the first part, the conventional PWM-DTC drive is described and Kalman filter is utilized to filter components of stator current vector those are assumed to be disturbed by white noise. The second part contains simulation results that are obtained in different cases of load torque, process and measurement noise covariances. The integral time absolute error (ITAE) performance index, undershoot, ripple of important quantities are used to compare the conventional drive structure and proposed drive structure with Kalman filter. The simulation results confirm the expected dynamic response of the proposed structure

A Large-Scale Study of a Sleep Tracking and Improving Device with Closed-loop and Personalized Real-time Acoustic Stimulation

Various intervention therapies ranging from pharmaceutical to hi-tech tailored solutions have been available to treat difficulty in falling asleep commonly caused by insomnia in modern life. However, current techniques largely remain ill-suited, ineffective, and unreliable due to their lack of precise real-time sleep tracking, in-time feedback on the therapies, an ability to keep people asleep during the night, and a large-scale effectiveness evaluation. Here, we introduce a novel sleep aid system, called Earable, that can continuously sense multiple head-based physiological signals and simultaneously enable closed-loop auditory stimulation to entrain brain activities in time for effective sleep promotion. We develop the system in a lightweight, comfortable, and user-friendly headband with a comprehensive set of algorithms and dedicated own-designed audio stimuli. We conducted multiple protocols from 883 sleep studies on 377 subjects (241 women, 119 men) wearing either a gold-standard device (PSG), Earable, or both concurrently. We demonstrate that our system achieves (1) a strong correlation (0.89 +/- 0.03) between the physiological signals acquired by Earable and those from the gold-standard PSG, (2) an 87.8 +/- 5.3% agreement on sleep scoring using our automatic real-time sleep staging algorithm with the consensus scored by three sleep technicians, and (3) a successful non-pharmacological stimulation alternative to effectively shorten the duration of sleep falling by 24.1 +/- 0.1 minutes. These results show that the efficacy of Earable exceeds existing techniques in intentions to promote fast falling asleep, track sleep state accurately, and achieve high social acceptance for real-time closed-loop personalized neuromodulation-based home sleep care.Comment: 33 pages, 8 figure

THỰC TRẠNG CANH TÁC DỪA TẠI TỈNH BẾN TRE, VIỆT NAM

Coconut is an important cash crop in Ben Tre Province, Vietnam, which has a lot of value. This study aimed to determine the current status of coconut cultivation in Ben Tre province through secondary data collected from the Ben Tre Provincal Statistical Office as well as primary data provided by 150 farmers in five coconut cultivated districts consisting of Chau Thanh, Giong Trom, Ba Tri, Thanh Phu, and Binh Dai via participatory interview method. The results showed that coconut planting and harvesting areas in Ben Tre province have been a significant increase over the period from 2012 to 2022, with production increasing by 1.6 times, reaching 686,279 tonnes in 2022. The predominant coconut cultivated method was specialised farming, with most households using tall coconut varieties. Planting density ranged from 160 to 240 trees per hectare. Flowering of the coconut plants was within 3 to 6 years of planting. Fertilization application was 4 to 6 times year-1 during the business period. Besides, insect pests and diseases on the coconut plants had been controlled by pesticides with 3 to 6 times per year. Coconut fruit yields were depended on variety and cultivation techniques, averaging 80 to 100 fruits tree-1 year-1 and 40 to 80 fruits tree-1 year-1 for dwarf and tall coconuts, respectively. The investment cost for coconut gardens ranged from 10 to 30 million VND hectare-1 year-1, with average incomes of 30 to 100 million VND hectare-1 year-1, yielding profits of 30 to 60 million VND hectare-1 year-1.Cây dừa là cây trồng quan trọng của tỉnh Bến Tre có nhiều giá trị sử dụng. Nghiên cứu này nhằm đánh giá thực trạng canh tác dừa tại tỉnh Bến Tre dựa trên số liệu thứ cấp từ Cục Thống kê tỉnh Bến Tre và số liệu sơ cấp thông qua phỏng vấn 150 hộ trồng dừa tại 5 huyện gồm Châu Thành, Giồng Trôm, Ba Tri, Thạnh Phú và Bình Đại. Kết quả cho thấy, diện tích trồng và thu hoạch dừa tại tỉnh Bến Tre có xu hướng tăng mạnh trong 10 năm (2012–2022), sản lượng tăng gấp 1,6 lần và đạt 686.279 tấn vào năm 2022. Hình thức canh tác dừa chủ yếu chuyên canh, phần lớn các hộ sử dụng giống dừa cao, mật độ trồng dao động 160–240 cây/ha, cây dừa bắt đầu ra hoa sau 3–6 năm trồng, số lần bón phân trong thời kỳ kinh doanh là 4–6 lần/năm, quản lý sâu bệnh hại dừa chủ yếu bằng thuốc bảo vệ thực vật với 3–6 lần phun/năm. Năng suất dừa phụ thuộc vào giống và kỹ thuật canh tác, trung bình 80–100 quả/cây/năm đối với dừa lùn và 40–80 quả/cây/năm đối với dừa cao. Chi phí đầu tư cho vườn dừa 10–30 triệu đồng/ha/năm, thu nhập bình quân 30–100 triệu đồng/ha/năm và đem lại lợi nhuận 30–60 triệu đồng/ha/năm

INFLUENCE OF CULTIVATION OF CHLORELLA VULGARIS ON MICROORGANISMS IN SEAFOOD WASTEWATER

Microalgae cultivation in wastewater for many purposes has been investigated recently decade ago. In this study, Chlorella vulgaris was chosen to culture for examination of its influences on microorganisms of seafood wastewater in particular aerobic bacteria, Coliform and E. coli. The microalgae cultivation was realized in Erlenmeyer flasks containing seafood wastewater medium. Another was also grown in original medium called Sueoka medium for control. All experiments were set up until almost all Chlorella vulgaris decanted or flocculated in the bottom of flasks. The changes of bacteria counts including aerobic bacteria, Coliform and E. coli were measured to evaluate the impact of cultivation of Chlorella vulgaris on them in this sewage. Otherwise, the growth of microalgae has been also recorded for evaluating the effect of a new medium on metabolism of Chlorella vulgaris. The results showed that the bacteria counts were significantly reduced after day 3 of microalgae culture. These results have been calculated the efficiency of aerobic bacteria, Coliform and E. coli elimination out of wastewater medium represented approximately 70%, 81% and 90% respectively. These eliminations provided evidences of difficult metabolism of bacteria under the presence of microalgae as like as Chlorella vulgaris. In other words, the symbiosis of microalgae and bacteria in sewage could prevent the raising of bacteria counts