A flow cytometer based protocol for quantitative analysis of bloom-forming cyanobacteria (Microcystis) in lake sediments

A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw (dry weight)/mL dilution combined with 200 W x 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3x10(4) cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 mu m in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystis flos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different-sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium.A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw (dry weight)/mL dilution combined with 200 W x 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3x10(4) cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 mu m in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystis flos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different-sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium

大學生生活壓力、認知型態與憂鬱傾向相關之研究

[[abstract]]本研究的目的在探討台灣地區大學生尤鬱傾向的症狀表現；生活壓力與尤鬱傾向的關 係；認知型態與尤鬱傾向的關係；并探討生活壓力、認知型態與尤鬱傾向之間的關係 。根據研究目的，本研究提出九項研究假設加以驗證。 本研究以九所大專院校四個年級的學生為研究對象，使用問題卷調查法從事資料搜集 ，實得有效問卷的人數男生199 人, 女生243 人, 共計442 人。為搜集有關資料，本 研究以五種量表為測量工具：「生活壓力量表」、「認知三元素量表」、「偏差態度 量表」、「認知錯誤量表」以及「貝克氏尤鬱量表」。所得資料分別以因素分析、積 差相關分析、卡方獨立性檢定、二因子變異數分析及逐步多元回歸分析等統計方法處 理。結果發現： 1.大學生尤鬱傾向的表現主要是以認知方面的偏差及情緒為主, 包括自我概念的貶抑 、對自我及環境的不滿、罪惡感、悲觀及情緒鬱悶等。 2.生活壓力與尤鬱傾向的關係：客觀的生活壓力與大學生尤鬱傾向在統計上有正相關 存在，主觀正向的生活壓力與大學生尤鬱傾向的相關係數未達統計上顯著水準，而主 觀負向的生活壓力與大學生尤鬱傾向在統計上有正相關存在。 3.大學生高、低尤鬱傾向組在整體生活事件發生平均數上并沒有太大差異，但有一些 生活事件二組的遭遇比例達統計上顯著差異。 4.大學生尤鬱傾向分別與認知三元素、偏差態度及認知錯誤等三種認知型態在統計上 有正相關存在，顯示大學生的尤鬱傾向與認知偏差有密切的關係。 5.認知三元素、偏差態度及認知錯誤等三種認知型態在不同生活壓力與尤鬱傾向之間 在統計上均不具交互作用，而不同尤鬱傾向的大學生在三種認知型態上均具有統計上 顯著差異。進一步比較顯示高尤鬱傾向組的大學生比低尤鬱傾向組的大學生持有更多 認知上的偏差。 6.以客觀生活壓力、主觀生活壓力、認知三元素、偏差態度及認知錯誤為觀測變項， 尤鬱傾向為依變項進行逐步多元回歸分析，結果發現認知偏差與生活壓力可以有效的 說明尤鬱傾向，而且影響尤鬱傾向最重要的因素是個人對自己、對生活經驗及對未來 的認知偏差。

表面處理後SS41之剪斷面研究

[[abstract]]本研究是利用一般下料模具，在曲軸沖床上作剪切加工，模具所用沖頭端面有不同形 式剪角，下模則無。以不同的間隙，對SS41、SS41鍍鉻與噴覆陶瓷, 沖剪不同料片， 厚度lmm,探討四種不同沖頭端部形狀與不同間隙對SS41材料鍍層後之剪斷面影響，並 且印證SS41材料之剪斷過程中，模輥、塑性變形（擦光帶）、撕裂等三部份之比例， 並瞭解此三部份在材料中流動過程中顯微組織變化情形，然後測量與觀察料片之邊緣 品質，比較其差異，分別找出上述三種材料之適當沖頭端面形狀與間隙。並以平口沖 頭 ，對料片作不同深度剪切，印證剪切過程。 結論如下： 1.SS41和SS41鍍鉻適合平口沖頭、4％t間隙剪切。 2.SS41噴覆陶瓷以平口沖頭、1％t間隙剪切, 料片邊緣陶瓷脫落較少。 3.SS41模輥形成約在20％t 剪切深度,晶粒在刀口附近彎曲拉長比中心大。 4.85％t 剪切深度尚未發現裂痕. 5.沖頭與下模之磨損, 紙出現傾斜磨耗。 6.1％t間隙剪斷面上有撕裂面, 不適合精密下料。 7.剪斷面之加工硬化程度, 以毛頭側較高。 8.料片之邊緣比中心硬度高。

Edge computing assisted autonomous flight for UAV: Synergies between vision and communications

Autonomous flight for UAVs relies on visual information for avoiding obstacles and ensuring safe collision-free flight. In addition to visual clues, safe UAVs often need connectivity with the ground station. In this article, we study the synergies between vision and communications for edge-computing-enabled UAV flight. By proposing a framework of edge computing assisted autonomous flight (ECAAF), we illustrate that vision and communications can interact with and assist each other with the aid of edge computing and offloading, and further speed up UAV mission completion. ECAAF consists of three functionalities that are discussed in detail: edge computing for 3D map acquisition, radio map construction from the 3D map, and online trajectory planning. During ECAAF, the interactions of communication capacity, video offloading, 3D map quality, and channel state of the trajectory form a positive feedback loop. Simulation results verify that the proposed method can improve mission performance by enhancing connectivity. Finally, we conclude with some future research directions.Accepted Author ManuscriptLearning & Autonomous Contro

Analysis of the cohesion/adhesion proportion around bitumen-mineral failure interface under tensile loading

The occurrence of cohesive/adhesive hybrid failure at the bitumen-aggregate interface is widely acknowledged, however, the quantitative evaluation of the cohesion/adhesion proportion is relatively weak. This study explored cohesive/adhesive hybrid failure and provided a quantitative analysis of the proportion between cohesion and adhesion. For this reason, this study considered a variety of experimental factors that included temperature (5 °C, 15 °C, and 25 °C), mineral morphology (three mineral types and three surface textures), and measured film thickness (varying from 10 μm to 900 μm). By performing the bonding strength test, the strength was recorded and interface failure was accordingly captured. The results indicated that the cohesion/adhesion proportion varied significantly with the temperature, mineral morphology, and measured film thickness. In addition, it was found that bonding strength decreased with the increase in the film thickness and temperature, which can be well explained by variation in adhesion/cohesion proportion. Complete cohesive failure was observed when the film thickness increased beyond a critical value at a relatively high temperature. An additional noteworthy finding was the resemblance of a lunar crater for the failure interface at high temperatures, signifying the heterogeneous composition of the bituminous binder around the interface.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Pavement Engineerin

Linear fractional order controllers: A survey in the frequency domain

Today, there is a great tendency toward using fractional calculus to solve engineering problems. The control is one of the fields in which fractional calculus has attracted a lot of attention. On the one hand, fractional order dynamic models simulate characteristics of real dynamic systems better than integer order models. On the other hand, Fractional Order (FO) controllers outperform Integer Order (IO) controllers in many cases. FO-controllers have been studied in both time an frequency domain. The latter one is the fundamental tool for industry to design FO-controllers. The scope of this paper is to review research which has been carried out on FO-controllers in the frequency domain. In this review paper, the concept of fractional calculus and their applications in the control problems are introduced. In addition, basic definitions of the fractional order differentiation and integration are presented. Then, four common types of FO-controllers are briefly presented and after that their representative tuning methods are introduced. Furthermore, some useful continuous and discrete approximation methods of FO-controllers and their digital and analogue implementation methods are elaborated. Then, some Matlab toolboxes which facilitate utilizing FO calculus in the control field are presented. Finally, advantages and disadvantages of using FO calculus in the control area are discussed. To wrap up, this paper helps beginners to get started rapidly and learn how to select, tune, approximate, discretize, and implement FO-controllers in the frequency domain.Accepted Author ManuscriptMechatronic Systems Desig

Temperature effects on fatigue delamination behavior in thermoset composite laminates

Temperature can significantly affect fatigue delamination growth (FDG) behavior in composites, while fiber bridging has been frequently reported during FDG. The focus of this study was therefore on investigating temperature effects on FDG behavior with fiber bridging. Mode I fatigue delamination experiments were conducted on a thermoset composite laminates M30SC/DT120 at different temperatures. The Paris relation and fatigue resistance curve (i.e. fatigue R-curve) were used to interpret bridging effects on FDG behavior and to explore temperature effects on fiber bridging development. A modified Paris relation was employed to determine the effects of temperature on the intrinsic FDG behavior at the crack front excluding fiber bridging. The Paris interpretations clearly demonstrate that fiber bridging can significantly retard FDG behavior at different temperatures. Temperature can have different effects on fiber bridging development and the intrinsic FDG behavior. Particularly, elevated temperature can promote more bridging fibers, whereas decreased temperature has negligible influence on fiber bridging. When looking at the intrinsic delamination resistance, mode I FDG can accelerate at elevated temperature but decrease at freezing temperature. Fractographic examinations indicate that fiber/matrix interface debonding is the dominant damage mechanism in mode I FDG at different temperatures. Elevated temperature can lead to the weakening of interface adhesion, contributing to faster intrinsic mode I FDG behavior and more fiber bridging development. And a semi-empirical fatigue model based on normalization was finally proposed to determine mode I intrinsic FDG behavior at different temperatures for engineering applications.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Structural Integrity & CompositesGroup Alderlieste