27 research outputs found
The local uniform convergence of positive harmonic function sequence
The Harnack distance on space and its conformal invariance were constructed and studied by Herron. In this paper, we obtain the Harnack distance on domains in . Then, we use this concept to investigate some properties of the positive harmonic function class. These results are obtained in the complex plane, so it is advantageous to take some tools of the complex analysis. The main result of this paper is the property of the local uniform convergence of the positive harmonic sequences on a domain in the complex plane.The Harnack distance on space and its conformal invariance were constructed and studied by Herron. In this paper, we obtain the Harnack distance on domains in . Then, we use this concept to investigate some properties of the positive harmonic function class. These results are obtained in the complex plane, so it is advantageous to take some tools of the complex analysis. The main result of this paper is the property of the local uniform convergence of the positive harmonic sequences on a domain in the complex plane
Primary Evaluation on Growth Performances of Stress Negative Piétrain Pigs Raised in Hai Phong Province of Vietnam
peer reviewedThe present study was carried out on 19 stress negative Piétrain pigs (Pietrain ReHal), consisting of 13 gilts and 6 young boars imported from Belgium, raised in the livestock farm of Dong Hiep (Hai Phong) in order to evaluate growth performances and their adaptability in the North of Vietnam. Results showed that the average body weight of the whole herd at 2, 4, 5.5, and 8.5 months old was 19.05, 51.05, 85.82, and 119.47 kg, respectively. During the growing periods, except the first stage, the male grew faster than the female and the pigs of the CT genotype grew faster than those of CC genotype although the difference was not significant (P>0.05). The average daily gain (ADG) was 528.56 grams for the whole herd. The ADG was higher for the male (546.48 grams) than for the female (520.29 grams), and its was higher for the CT than the CC, but the difference was not statistically significant (P>0.05). The feed conversion ratio (FCR) was 2.69 kg. The estimated lean percentage at 8.5 months old was 64.08%. The results indicate that Piétrain stress negative pigs could develop well on the farm conditions in Hai Phong, Vietnam
A Survey on Some Parameters of Beef and Buffalo Meat Quality
A survey was carried out on 13 Vietnamese Yellow cattle, 14 LaiSind cattle and 18 buffalos in
Hanoi to estimate the quality of longissimus dorsi in terms of pH, color, drip loss, cooking loss and tenderness at 6 different postmortem intervals. It was found that the pH value of longissimus dorsi was not significantly different among the 3 breeds (P>0.05), being reduced rapidly during the first 36 hours postmortem, and then stayed stable. The value was in the range that was considered to be normal. Conversely, the color values L*, a* and b* tended to increase and also stable at 36 hours postmortem, except that for LaiSind cattle at 48 hours. According to L* scale, the meat of Yellow and LaiSind cattle met the normal quality but the buffalo meat was considered to be dark cutters. The tenderness of longissimus dorsi was significantly different among the breeds (P<0.05). The value was highest at 48 hours and then decreased for LaiSind and buffalo, but for Yellow cattle the value decreased continuously after slaughtering In terms of tenderness buffalo meat and Yellow cattle meat were classified as “intermediate”, while LaiSind meat was out of this interval and classified as “tough”. Drip loss ratio was increased with the time of preservation (P<0.05). The cooking loss ratio was lowest at 12 hours and higher at the next period, but there was no significant difference among the periods after 36 hours postmotem.Peer reviewe
A novel control method to maximize the energy-harvesting capability of an adjustable slope angle wave energy converter
This paper introduces a novel control approach to maximizing the output energy of an adjustable slope angle wave energy converter (ASAWEC) with oil-hydraulic power take-off. Different from typical floating-buoy WECs, the ASAWEC is capable of capturing wave energy from both heave and surge modes of wave motions. For different waves, online determination of the titling angle plays a significant role in optimizing the overall efficiency of the ASAWEC. To enhance this task, the proposed method was developed based on a learning vector quantitative neural network (LVQNN) algorithm. First, the LVQNN-based supervisor controller detects wave conditions and directly produces the optimal titling angles. Second, a so-called efficiency optimization mechanism (EOM) with a secondary controller was designed to regulate automatically the ASAWEC slope angle to the desired value sent from the supervisor controller. A prototype of the ASAWEC was fabricated and a series of simulations and experiments was performed to train the supervisor controller and validate the effectiveness of the proposed control approach with regular waves. The results indicated that the system could reach the optimal angle within 2s and subsequently, the output energy could be maximized. Compared to the performance of a system with a vertically fixed slope angle, an increase of 5% in the overall efficiency was achieved. In addition, simulations of the controlled system were performed with irregular waves to confirm the applicability of the proposed approach in practice
Proposition and experiment of a sliding angle self-tuning wave energy converter
The hydraulic power-take-off mechanism (HPTO) is one of the most popular methods in wave energy converters (WECs). However, the conventional HPTO with a fixed direction motion has some drawbacks which limit its power capture capability. This paper proposes a sliding angle self-tuning wave energy converter (SASTWEC) to find the optimal sliding angle automatically, with the purpose of increasing the power capture capability and energy efficiency. Furthermore, a small scale WEC test rig was fabricated and a wave making source has been employed to verify the sliding angle performance and efficiency of the proposed system throughout experiments
XÂY DỰNG BỘ CHỈ TIÊU PHÁT TRIỂN BỀN VỮNG VỀ CÁC LĨNH VỰC KINH TẾ, XÃ HỘI VÀ MÔI TRƯỜNG CÁC TỈNH TÂY NGUYÊN
A sustainable development indication set plays a very important role for assessing, monitoring the sustainable development status in a region, supporting policy, decision makers to propose confident decisions to control economic, social, and environmental themes toward sustainable developmet. The content, procedure, methodology, and methods to establish the sustainable development indicator set in Tay Nguyen (SDI) were figured out; proposing a list of sustainable development indicators for Tay Nguyen consisting of 77 indicators at regional scale, 70 indicators at provincial scale, 49 indicators at district scale. The SDI could comprehensively show overall development process toward sustainable by 13 themes (economic field - 3 themes; social field - 5 themes; and environmental field - 5 themes). The paper outlined the SDI’s definition and indicated SDI’s significance through linkages between the sustainable development indicators and sustainable development themes.ReferencesLê Thạc Cán, Trần Thùy Chi, Nguyễn Thế Chinh, Nguyễn Viết Thịnh, Ngô Đăng Trí, Nguyễn Thanh Tuấn, Trần Văn Ý và James Hennessy, 2013. Kết quả bước đầu của Đề tài “Nghiên cứu xây dựng Bộ chỉ tiêu phát triển bền vững các lĩnh vực kinh tế xã hội và môi trường các tỉnh Tây Nguyên”, Tạp chí Khoa học Công nghệ Việt Nam, ISSN 1859-4794. No14, 2013, p 61-64. Dhakal S. 2002. Report on Indicator related research for Kitakyushu Initiative. Ministry of Environment, Japan. Harold A. Linstone, Murray Turoff, 2002. The Delphi Method: Techniques and Applications. Hui-Chun Chu, Gwo-Jen Hwang, 2008. A Delphi-based approach to developing expert systems with the cooperation of multiple experts, Expert Systems with Applications, 34(4), 2826- 840. (SCI). Jean Hugé, Hai Le Trinh, Pham Hoang Hai, Jan Kuilman and Luc Hens, 2009. Sustainability indicators for clean development mechanism projects in Vietnam, Springer Netherlands. Environment, Development and Sustainability, August 2010, Volume 12, Issue 4, pp 561-571. Trần Văn Ý, Lê Thạc Cán, Trần Thùy Chi, Nguyễn Thế Chinh, Ngô Đăng Trí, Nguyễn Viết Thịnh, Nguyễn Thanh Tuấn, 2013. Bộ chỉ tiêu phát triển bền vững về các lĩnh vực kinh tế, xã hội và môi trường các tỉnh Tây Nguyên. Kỷ yếu hội thảo quốc tế lần thứ tư, Việt Nam học, Nhà xuất bản Khoa học xã hội, Hà Nội, ngày 26-28/11/2012, tập IV, 386-400. Bộ Kế hoạch và Đầu tư, 2010. Hệ thống chỉ tiêu thống kê quốc gia (Ban hành theo Quyết định số 43/2010/QĐ/TTg ngày 02 tháng 6 năm 2010 của Thủ tướng Chính phủ). UNDP và MPI, 2005. Identification of a sustainable development indicators set and mechanism for building a sustainable development database in Vietnam (Project VIE/01/021 “Implementation of Vietnam Agenda 21”) United Nations, 2007. Indicators of Sustainable Development: Guidelines and Methodologies. Thủ tướng Chính phủ, 2012. Các chỉ tiêu giám sát và đánh giá phát triển bền vững Việt Nam giai đọan 2011-2020 (Ban hành kèm theo Quyết định số 432/QĐ-TTg ngày 12 tháng 4 năm 2012 của Thủ tướng Chính phủ). Thủ tướng Chính phủ, 2013. Bộ chỉ tiêu giám sát, đánh giá phát triển bền vững địa phương giai đoạn 2013-2020 (Ban hành kèm theo Quyết định số 2157/QĐ-TTg ngày 11 tháng 11 năm 2013 của Thủ tướng Chính phủ). A sustainable development indication set plays a very important role for assessing, monitoring the sustainable development status in a region, supporting policy, decision makers to propose confident decisions to control economic, social, and environmental themes toward sustainable developmet. The content, procedure, methodology, and methods to establish the sustainable development indicator set in Tay Nguyen (SDI) were figured out; proposing a list of sustainable development indicators for Tay Nguyen consisting of 77 indicators at regional scale, 70 indicators at provincial scale, 49 indicators at district scale. The SDI could comprehensively show overall development process toward sustainable by 13 themes (economic field - 3 themes; social field - 5 themes; and environmental field - 5 themes). The paper outlined the SDI’s definition and indicated SDI’s significance through linkages between the sustainable development indicators and sustainable development themes
A novel control method to maximize the energy-harvesting capability of an adjustable slope angle wave energy converter
Associations of Underlying Health Conditions With Anxiety and Depression Among Outpatients: Modification Effects of Suspected COVID-19 Symptoms, Health-Related and Preventive Behaviors
Objectives: We explored the association of underlying health conditions (UHC) with depression and anxiety, and examined the modification effects of suspected COVID-19 symptoms (S-COVID-19-S), health-related behaviors (HB), and preventive behaviors (PB).Methods: A cross-sectional study was conducted on 8,291 outpatients aged 18–85 years, in 18 hospitals and health centers across Vietnam from 14th February to May 31, 2020. We collected the data regarding participant's characteristics, UHC, HB, PB, depression, and anxiety.Results: People with UHC had higher odds of depression (OR = 2.11; p < 0.001) and anxiety (OR = 2.86; p < 0.001) than those without UHC. The odds of depression and anxiety were significantly higher for those with UHC and S-COVID-19-S (p < 0.001); and were significantly lower for those had UHC and interacted with “unchanged/more” physical activity (p < 0.001), or “unchanged/more” drinking (p < 0.001 for only anxiety), or “unchanged/healthier” eating (p < 0.001), and high PB score (p < 0.001), as compared to those without UHC and without S-COVID-19-S, “never/stopped/less” physical activity, drinking, “less healthy” eating, and low PB score, respectively.Conclusion: S-COVID-19-S worsen psychological health in patients with UHC. Physical activity, drinking, healthier eating, and high PB score were protective factors
Comparison of the
Multi-criteria decision-making (MCDM) methods are used in many fields so as to rank alternatives and find the best one. However, rank reversal after adding or removing an alternative can occur in using some of the methods. In this study, two methods RAFSI and PIV were compared for application of making multi-criteria decisions. They are known to be capable of avoiding rank reversal problems. Sixteen 9XC steel turning tests were performed for the experiment. Tool holder length, spindle speed, feed rate and depth of cut are parameters that vary in each test. Three criteria for evaluating the turning process consist of MRR, RE and Ra. Four methods including MEREC, ROC, RS and EQUAL were used for determining weights of the criteria. The blend of two multi-criteria decision making methods (RAFSI and PIV) with four weight-determining methods resulted in eight ranking options. This is a new approach of the study. A positive outcome was reached that all eight ranking options identified the same best test. The best experiment must ensure to have maximum MRR and minimum RE and Ra simultaneously. A detailed discussion of the ranking results in each case was also carried out. Finally, the directions and issues that need to be studied further were pointed out in this paper as well