Comparison of optimum conditions when extracting PHAs from different waste sludge sources

Biological wastewater treatment plants produce great amounts of sludge daily. It is a very big loading (cost) for treating the waste sludge. Polyhydroxyalkanoates are a family of polyhydroxyesters. The technologies of extracting PHAs from wasted sewage sludges of municipal wastewater, fermentation industry and husbandry were developed in the study. In the NaOCl/SDS extraction technology, the concentration of NaOCl and liquid-solid ratio are two essential factors directly influencing extraction efficiency. The experimental results verified under the optimal conditions for extracting PHAs, the content of recovered PHAs was 44.2±0.89 mgPHA/gVSS and the purity of recovered PHAs was >99.5 wt% for the waste sludge from municipal wastewater treatment plants. For fermentation industry sludge, under the adequate extraction conditions for PHAs recovery, the content and purity of recovered PHAs were 18.8±0.66 mgPHA/gVSS and 50.6±6.83 wt%, respectively. For husbandry sludge, the content and purity of recovered PHAs were 33.7±0.16 mgPHA/gVSS and 76.7±5.2 wt%, respectively

Nocturnal CPAP improves walking capacity in COPD patients with obstructive sleep apnoea

BACKGROUND: Exercise limitation is an important issue in patients with chronic obstructive pulmonary disease (COPD), and it often co-exists with obstructive sleep apnoea (overlap syndrome). This study examined the effects of nocturnal continuous positive airway pressure (CPAP) treatment on walking capacity in COPD patients with or without obstructive sleep apnoea. METHODS: Forty-four stable moderate-to-severe COPD patients were recruited and completed this study. They all underwent polysomnography, CPAP titration, accommodation, and treatment with adequate pressure. The incremental shuttle walking test was used to measure walking capacity at baseline and after two nights of CPAP treatment. Urinary catecholamine and heart rate variability were measured before and after CPAP treatment. RESULTS: After two nights of CPAP treatment, the apnoea-hypopnoea index and oxygen desaturation index significantly improved in both overlap syndrome and COPD patients, however these changes were significantly greater in the overlap syndrome than in the COPD group. Sleep architecture and autonomic dysfunction significantly improved in the overlap syndrome group but not in the COPD group. CPAP treatment was associated with an increased walking capacity from baseline from 226.4 ± 95.3 m to 288.6 ± 94.6 m (P < 0.05), and decreased urinary catecholamine levels, pre-exercise heart rate, oxygenation, and Borg scale in the overlap syndrome group. An improvement in the apnoea-hypopnoea index was an independent factor associated with the increase in walking distance (r = 0.564). CONCLUSION: Nocturnal CPAP may improve walking capacity in COPD patients with overlap syndrome. TRIAL REGISTRATION: NCT0091426

A Systematic Study of the Stability, Safety, and Efficacy of the de novo Designed Antimicrobial Peptide PepD2 and Its Modified Derivatives Against Acinetobacter baumannii

Searching for new antimicrobials is a pressing issue to conquer the emergence of multidrug-resistant (MDR) bacteria and fungi. Antimicrobial peptides (AMPs) usually have antimicrobial mechanisms different from those of traditional antibiotics and bring new hope in the discovery of new antimicrobials. In addition to antimicrobial activity, stability and target selectivity are important concerns to decide whether an antimicrobial peptide can be applied in vivo. Here, we used a simple de novo designed peptide, pepD2, which contains only three kinds of amino acid residues (W, K, L), as an example to evaluate how the residues and modifications affect the antimicrobial activity against Acinetobacter baumannii, stability in plasma, and toxicity to human HEK293 cells. We found that pepI2 with a Leu→Ile substitution can decrease the minimum bactericidal concentrations (MBC) against A. baumannii by one half (4 μg/mL). A D-form peptide, pepdD2, in which the D-enantiomers replaced the L-enantiomers of the Lys(K) and Leu(L) residues, extended the peptide half-life in plasma by more than 12-fold. PepD3 is 3-residue shorter than pepD2. Decreasing peptide length did not affect antimicrobial activity but increased the IC50 to HEK293 cells, thus increased the selectivity index (SI) between A. baumannii and HEK293 cells from 4.7 to 8.5. The chain length increase of the N-terminal acyl group and the Lys→Arg substitution greatly enhanced the hemolytic activity, hence those modifications are not good for clinical application. Unlike colistin, the action mechanism of our peptides relies on negatively charged lipids rather than lipopolysaccharides. Therefore, not only gram-negative bacteria but also gram-positive bacteria can be killed by our peptides

Mathematical Derivation of the Stability of annular-jet flow

在噴流的穩定性分析研究中，目前圓柱型噴流的研究已經非常完整，不過在環型噴流的研究中，大多數仍然是以無黏性假設或軸對稱的假設下分析穩定性。因此在本文中分析環型噴流的線性穩定性，是以考慮黏滯性與非軸對稱的條件下來分析，利用Lin(1994)的推導方法，來求得環型噴流的解析解，希望藉此以提供較完整的分析及預測。The stability of round jet has been researched completely. But most of analyses of annular jet stability are researched in the hypothesis of the symmetry or inviscid. In this text, we analyze the stability of annular jet in the considering of viscid and asymmetry. We use Lin (1994)’s method to find the dispersion relation of these system and provide more accurate result and prediction.謝誌 Ⅰ 摘要 Ⅱ 目錄 Ⅳ 圖目錄 Ⅵ 符號說明 Ⅶ 第一章 引言 1 1.1 文獻回顧 1 1.2 研究動機 5 第二章 模型建立 7 2.1 基本假設 7 2.2 無因次化 8 2.3 基態流場 13 第三章 穩定性分析 15 3.1 線性化擾動方程式 15 3.2 正交模式展開 18 3.3 特徵方程式的通解 22 3.4 求頻散關係式 30 第四章 特例分析 35 4.1 中空噴流 35 4.2 圓柱噴流 38 第五章 結論與展望 45 參考文獻 4

Influence of sludge retention time on tolerance of copper toxicity for polyphosphate accumulating organisms linked to polyhydroxyalkanoates metabolism and phosphate removal

This study explored the influence of sludge retention time (SRT) on tolerance of copper invasion for polyphosphate accumulating organisms (PAOs) in an enhanced biological phosphorus removal (EBPR). The experimental data showed the anaerobic polyhydroxyalkanoates (PHA) storage for the sludge at 10d SRT was less influenced by copper invasion than those at 5d and 15d SRTs. The reaction of PAOs aerobically taking up phosphate for the sludge at 5d or 15d SRT almost ceased at 2 mg Cu L^(−1), whereas PAOs in the sludge at 10d SRT retained half of the ability to take up phosphate. Both the PHAs degradation and synthesis rates decreased with increasing copper concentration, regardless of the SRTs. However, the copper inhibition of the former was greater than that of the later

Deployment Optimization of Wireless Mesh Networks Considering End-to-End Throughput Fairness

無線網狀網路(WMNs)為一項可提供寬頻存取網際網路的「最後一里(last mile) 」技術，能夠提供可靠且更加廣泛的服務給無線使用者。研究顯示，由於與出口閘道較遠的用戶能夠使用的頻寬較少，因此在建置無線網狀網路的同時如何兼顧網路效能與服務品質(QoS)是重要的議題。 本論文提出一個最大最小公平性(max-min fairness)的數學模型，在網路規劃階段考慮營運階段的端點對端點流量公平性問題(end-to-end throughput fairness)，並且聯合考慮網路節點佈署、出口閘道佈署、傳輸能量控制、信道佈署、路由規劃以及流量控制最佳化。本論文所提出的解決方案是基於拉格蘭日鬆弛法(Lagrangean Relaxation)為基礎所開發之啟發式演算法。 本論文提出前置處理方法(preprocessing)處理原先棘手的問題，並提出了適合多信道多網卡無線網狀網路(multi-channel multi-radio wireless mesh networks)的最大最小流量控制演算法(max-min flow control algorithm)。實驗結果顯示，以拉格蘭日對偶解(Lagrangean dual solution)為提示開發的啟發式演算法能夠有效地找到好的解。此外結果也顯示出，在本論文所設計的環境下，平均地將信道分配給使用者通訊(user communications)與骨幹通訊(backbone communications)能夠更有效地利用網路資源。Wireless Mesh Networks (WMNs) are considered as a technology for last-mile broadband Internet access to provide reliable and more extensive connectivity to wireless users. Previous studies stated that users with longer paths must endure lower bandwidth allocation; as a result, performance and Quality of Service (QoS) are important factors in network planning stage. In this paper, a max-min fairness mathematical model is proposed, which jointly consider end-to-end throughput fairness problem with network deployment, transmission power control, channel assignment, routing and flow control optimization. The solution approach introduced in this paper is a heuristic algorithm derived from Lagrangean Relaxation based problem formulation. This thesis proposes a preprocessing stage for handling the originally intractable problem. A max-min flow control algorithm is established for multi-channel multi-radio wireless mesh networks. The experiment results show the heuristic algorithm, which takes dual solutions of Lagrangean Relaxation method as hints, can efficiently get a good solution. And the results also show that network designers can better use the resource through evenly allocate available channels to user communications and backbone communications

Color multiplexing method to capture front and side images with a capsule endoscope

This paper proposes a capsule endoscope (CE), based on color multiplexing, to simultaneously record front and side images. Only one lens associated with an X-cube prism is employed to catch the front and side view profiles in the CE. Three color filters and polarizers are placed on three sides of an X-cube prism. When objects locate at one of the X-cube's three sides, front and side view profiles of different colors will be caught through the proposed lens and recorded at the color image sensor. The proposed color multiplexing CE (CMCE) is designed with a field of view of up to 210 deg and a 180 lp/mm resolution under f-number 2.8 and overall length 13.323 mm. A ray-tracing simulation in the CMCE with the color multiplexing mechanism verifies that the CMCE not only records the front and side view profiles at the same time, but also has great image quality at a small size

Simultaneous Carbamazepine and Phosphate Removal from a Moving-Bed Membrane Bioreactor Effluent by the Electrochemical Process: Treatment Optimization by Factorial Design

Pharmaceutical and personal care products are frequently used in various fields and released into water bodies from the outlets of wastewater treatment plants. These products can harm the environment and human health even at low concentrations. Carbamazepine (CBZ), the most persistent pharmaceutical, has frequently been found in surface waters that bypassed the secondary treatments of conventional activated sludge. In addition, the treatment of phosphate in wastewater by the electrochemical process has recently attracted much attention because of its ability to remove, recover, and prevent environmental problems associated with eutrophication. This study proposes using the electrochemical process as an advanced oxidation process to simultaneously treat CBZ and phosphate from the moving-bed membrane bioreactor effluent. The study includes a long-term survey of CBZ treatment efficiency and common parameters of synthetic wastewater in the moving-bed membrane bioreactor system. Afterward, the electrochemical process is applied as an advanced oxidation process for the simultaneous removal of CBZ and phosphate from the moving-bed membrane bioreactor. Under the investigated conditions, CBZ has proven not to be an inhibitor of microbial activity, as evidenced by the high extent of chemical oxygen demand and nutrient removal. Using a factorial design, the electrochemical process using Pt/Ti as anode and cathode under optimal conditions (reaction time&mdash;80 min, bias potential&mdash;3 V, and electrode distance&mdash;1 cm) resulted in as high as 56.94% CBZ and 95.95% phosphate removal, respectively. The results demonstrated the ability to combine an electrochemical and a moving-bed membrane bioreactor process to simultaneously remove CBZ and phosphate in wastewater

How universities can work together with local communities to create a green, sustainable future

Over the past few years, National Chi Nan University (NCNU) has made significant achievements in its development as a “green university.” Besides continuing to implement sustainable development of its campus, NCNU has also been implementing the “Citizenship Cultivation Plan,” “University without Boundary Project” and “University Social Responsibility (USR) Plan,” using the local community as a test-bed, and working actively to integrate NCNU’s curriculum with the community, so as to enhance awareness of local environmental issues among students, faculty members and local residents, and build consensus of sustainable environmental development. NCNU has implemented a range of action plans and practical courses of environmental education to work together with local residents for environmental issues, such as water resources, air quality, waste, etc. Through these activities, NCNU’s students and faculty members and local residents are able to develop a better understanding of the environment, and how they can make a bigger contribution towards environmental protection. Regarding the international voluntary service activities, NCNU has endeavored to fulfil its social responsibility as a university. Under the dynamic leadership of President Dr. Yuh-Long Su, College of Science and Technology and College of Management have joined forces with “Chunghwa International Sunshine Charitable Association” established by Taiwanese businesspeople in Southeast Asia, using NCNU’s knowhow and technology to build the water purification systems in Cambodia, providing clean and safe drinking water for people in remote and disadvantaged areas. NCNU has strongly rooted in the local community with the content of the United Nations’ Sustainable Development Goals (SDGs) to build capabilities in four key areas - educational development, local action, industry-academia collaboration, and global integration - and to expand the scope of its activities from the local to the international. In the future, NCNU will continue devoting itself to sustainability and environmental issues, working wholeheartedly to meet its social responsibility goals as a university

Effect of Operational Parameters on the Removal of Carbamazepine and Nutrients in a Submerged Ceramic Membrane Bioreactor

Pharmaceuticals and personal care products have raised significant concerns because of their extensive use, presence in aquatic environments, and potential impacts on wildlife and humans. Carbamazepine was the most frequently detected pharmaceutical residue among pharmaceuticals and personal care products. Nevertheless, the low removal efficiency of carbamazepine by conventional wastewater treatment plants was due to resistance to biodegradation at low concentrations. A membrane bioreactor (MBR) has recently attracted attention as a new separation process for wastewater treatment in cities and industries because of its effectiveness in separating pollutants and its tolerance to high or shock loadings. In the current research, the main and interaction effects of three operating parameters, including hydraulic retention time (12–24 h), dissolved oxygen (1.5–5.5 mg/L), and sludge retention time (5–15 days), on removing carbamazepine, chemical oxygen demand, ammonia nitrogen, and phosphorus using ceramic membranes was investigated by applying a two-level full-factorial design analysis. Optimum dissolved oxygen, hydraulic retention time, and sludge retention time were 1.7 mg/L, 24 h, and 5 days, respectively. The research results showed the applicability of the MBR to wastewater treatment with a high carbamazepine loading rate and the removal of nutrients