Analytical evaluation of steady-state solute distribution in through- diffusion and membrane behavior test under non-perfectly flushing boundary conditions

The through-diffusion and membrane behavior testing procedure using a closed-system apparatus has been widely used for concurrent measurement of diffusion and membrane efficiency coefficients of low-permeability clay-based barrier materials.However,the common assumption of perfectly flushing conditions at the specimen boundaries could induce errors in analyses of the diffusion coefficients and membrane efficiencies.In this study,an innovative pseudo three-dimensional(3D)analytical method was proposed to evaluate solute distribution along the boundary surfaces of the soil-porous disks system,considering the non-perfectly flushing conditions.The results were consistent with numerical models under two scenarios considering different inflow/outflow positions.The proposed model has been demonstrated to be an accurate and reliable method to estimate solute distributions along the bound-aries.The calculated membrane efficiency coefficient and diffusion coefficient based on the proposed analytical method are more accurate,resulting in up to 50%less relative error than the traditional approach that adopts the arithmetic mean value of the influent and effluent concentrations.The retar-dation factor of the clay specimen also can be calculated with a revised cumulative mass approach.Finally,the simulated transient solute transport matched with experimental data from a multi-stage through-diffusion and membrane behavior test,validating the accuracy of the proposed method.

Biophysical warming patterns of an open-top chamber and its short-term influence on a Phragmites wetland ecosystem in China

Passive-warming, open-top chambers(OTCs) are widely applied for studying the effects of future climate warming on coastal wetlands. In this study, a set of six OTCs were established at a Phragmites wetland located in the Yellow River Delta of Dongying City, China. With data collected through online transmission and in-situ sensors, the attributes and patterns of realized OTCs warming are demonstrated.The authors also quantified the preliminary influence of experimental chamber warming on plant traits.OTCs produced an elevated average air temperature of 0.8°C(relative to controls) during the growing season(June to October) of 2018, and soil temperatures actually decreased by 0.54°C at a depth of 5 cm and 0.46°C at a depth of 30 cm in the OTCs. Variations in diel patterns of warming depend greatly on the heat sources of incoming radiation in the daytime versus soil heat flux at night. Warming effects were often larger during instantaneous analyses and influenced OTCs air temperatures from-2.5°C to 8.3°C dependent on various meteorological conditions at any given time, ranging from cooling influences from vertical heat exchange and vegetation to radiation-associated warming. Night-time temperature depressions in the OTCs were due to the low turbulence inside OTCs and changes in surface soilatmosphere heat transfer. Plant shoot density, basal diameter, and biomass of Phragmites decreased by23.2%, 6.3%, and 34.0%, respectively, under experimental warming versus controls, and plant height increased by 4.3%, reflecting less carbon allocation to stem structures as plants in the OTCs experienced simultaneous wind buffering. While these passive-warming OTCs created the desired warming effects both to the atmosphere and soils, pest damages on the plant leaves and lodging within the OTCs were extensive and serious, creating the need to consider control options for these chambers and the replicated OTCs studies underway in other Chinese Phragmites marshes(Panjin and Yancheng).

供应商选择问题的不确定性模型及遗传算法(英文)

供应商选择问题是物流领域内的一个重要问题,其目标函数就是在包括送达时间、原料质量和服务水平等的约束下使总花费最小.传统的确定性模型取得了较好的效果,但是由于其约束条件的随机性和模糊性,需要应用不确定性模型来更准确地描述和给出最优解.论文应用了不确定性模型描述这类供应商选择问题,这个不确定性模型就是一类特殊的机会约束规划模型,此类机会约束可以转化为相应的等价类,这样不确定性模型就可以转化为确定性模型,然后设计了解决这类问题的遗传算法.通过实例计算表明,不确定性优化模型及遗传算是解决供应商选择等这类不确定性智能商业问题的有效办法,有广泛的应用前景.

一种点相关统计特性的目标跟踪方法

提出了一种新颖、鲁棒的运动目标跟踪方法。在首帧图像建立特征点和物体中心点的关系,然后在后续帧图像使用Lucas Kanada跟踪方法跟踪这些特征点。利用这些特征点来计算一个物体中心位置的点集,并提出一种统计最优方法来鉴别那些存在跟踪误差较大的特征点,之后在计算中心点过程中把这些特征点剔除掉,并使用子图像匹配方法矫正存在跟踪误差的特征点。测试了8个实验视频,结果证明该算法不仅消弱了跟踪误差对中心位置计算的影响,而且基本消除了跟踪误差积累的弊端。

Enhance limit cycle oscillation in a wind flow energy harvester system with fractional order derivatives

Advances in material science and mathematics in conjunction with tech- nological needs have triggered the use of material and electric components with fractional order physical properties. This paper considers the mathematical model of a piezoelectric wind flow energy harvester system for which the capacitance of the piezoelectric material has fractional order current-voltage characteristics. Additionally the mechanical element is assumed to have fractional order damping. The analysis is focused on the effects of order of derivatives on the appearance and characteristics of limit circle oscillations （LCO）. It is obtained that, the order of derivatives to enhance the amplitude of LCO and lower the threshold condition leading to LCO. The domains of efficiency of the system are illustrated in various parameters spaces.

Energy harvesting by two magnetopiezoelastic oscillators with mistuning

We examine an energy harvesting system of two magnetopiezoelastic oscillators coupled by electric circuit and driven by harmonic excitation. We focus on the effects of synchronization and escape from a single potential well. In the system with relative mistuning in the stiffness of the har- vesting oscillators, we show the dependence of the voltage output for different excitation frequencies.

Recent progress in solution assembly of 2D materials for wearable energy storage applications

Wearable energy storage devices are desirable to boost the rapid development of flexible and stretchable electronics. Two-dimensional (2D) materials, e.g., graphene, transition metal dichalcogenides and oxides, and MXenes, have attracted intensive attention for flexible energy storage applications because of their ultrathin 2D structures, high surface-to-volume ratio, and unique physical/chemical properties. To achieve commercialization of 2D material-based wearable energy storage devices (2DM-WESDs), scalable and cost-efficient manufacturing is a critical challenge. Among existing manufacturing technologies, solution-based assembly strategies show strong potential to achieve low-cost and scalable production. A timely review of the recent progress in solution-based assembly strategies and the resultant 2DM-WESDs will be meaningful to guide the future development of 2DM-WESDs. In this review, first, a brief introduction of exfoliation and solution preparation of 2D material species from bulk materials is discussed. Then, the solution-based assembly strategies are summarized, and the advantages and disadvantages of each method are compared. After that, two major categories of 2DM-WESDs, supercapacitor and battery, are discussed, emphasizing their state-of-the-art energy storage performances and flexibilities. Finally, insights and perspectives on current challenges and future opportunities regarding the solution assembly of 2DM-WESDs are discussed.

High-resolution mass spectrometric characterization of dissolved organic matter from warm and cold periods in the NEEM ice core

Dissolved organic matter(DOM) is an important component of ice cores but is currently poorly characterized. DOM from one Holocene sample(HS, aged at 1600–4500 B.P.) and one Last Glacial Maximum sample(LS, aged at 21000–25000 B.P.) from the North Greenland Eemian Ice Drilling(NEEM) ice core were analyzed by ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS). CHO compounds contributed 50% of the compounds identified in negative-ionization mode in these two samples, with significant contributions from organic N, S, and P compounds, likely suggesting that marine DOM was an important source in these samples. Overall, the chemical compositions are similar between these two samples, suggesting their consistent DOM sources. However, subtle differences in the DOM between these two samples are apparent and could indicate differences in source strength or chemistry occurring through both pre-and post-depositional processes. For example, higher relative amounts of condensed carbon compounds in the HS DOM(5%), compared to the LS DOM(2%), suggest potentially important contributions from terrestrial sources. Greater incorporation of P in the observed DOM in the LS DOM(22%), compared to the HS DOM(13%), indicate more active microbiological processes that likely contribute to phosphorus incorporation into the DOM pool. Although these two samples present only a preliminary analysis of DOM in glacial/interglacial periods, the data indicate a need to expand the analysis into a broader range of ice-core samples, geographical locations, and glacial/interglacial periods.

Nature＇s Artistic Narrative

Many people have devoted their professional lives to translating and understanding the artistic narrative told by light, stones, bones, and blood. There is still much we do not understand about the epic saga told by nature about creativity and destruction, coherence and surprise, colors and lines, and so much else. But we can read in nature the major chapters of an improbable story about where we came from, how we got here, and what we are made of. The nature-the stories--from which we have emerged have led to our abilities to explicitly imagine, to create more complex and beautiful relationships, or to end our chapter.

Identifying Association Rules among Drugs in Prescription of a Single Drugstore Using Apriori Method

These days, health care systems such as pharmacies and drugstores normally produce high volumes of data. Consequently, utilizing data mining methods in health care systems has become a conventional process. In this research, Apriori algorithm has been applied to perform data mining using the data obtained from the prescriptions ordered within a pharmacy. Ten association rules were achieved from the assigned pharmaceutical drugs in those prescriptions using the aforementioned Apriori algorithm. The accuracy of these rules is also manually studied and reviewed by a physician. Among these association rules, Vitamin D and Calcium pills are the most interrelated medications, and Omeprazole and Metronidazole rankd second in terms of association. The results of this study provide useful feedback information about associations among drugs.

Transit Bus and Pedestrian Safety Analysis in the Context of Operator Improvements and Traffic Volume Assessment

Pedestrian safety related to public bus transit is an integral part of promoting sustainability especially in the urban setting. This concept has received significant attention within the last decade as transit agencies strive to make their systems more sustainable and safer at the same time. This study examined pedestrian collisions related to public transit buses in Philadelphia over a three-year study period from 2008 to 2011. The objective is to perform a detailed analysis on crash records, which provides the foundation on statistics for bus-pedestrian collision to allow for future studies in modeling work in this field. Results of this research provided insights on bus-pedestrian collisions in terms of bus maneuver, cause of crash, impact point of bus, and relation to hourly traffic volume. A strong correlation was found between traffic volume and bus-pedestrian collision rate in terms of hours of the day. For any given hour, an increase in collision frequency was found if the traffic volume exceeds a threshold of 5% of its average annual daily traffic. This serves as an indicator of locations that pedestrians are vulnerable at. Analyses were conducted to the fullest extent allowable by the limited dataset. This study presents findings that can be future developed and investigated in future studies. Additionally, countermeasures are recommended in each section that presents a critical area to address.

Himalayan Political and Cultural Challenges to Catholic Peacebuilding

The Himalayas exhibit multiple instances and stages of violent armed conflict and political instability.This paper will consider how the political and cultural realities of the Himalayas complexify the Catholic approach to pursuing a sustainable just peace.Peacebuilding emphasizes a holistic approach to conflict transformation,addressing the underlying causes of violence,while considering the goals and motivations of those involved.As a vital component of Catholic social teaching,peacebuilding articulates a comprehensive approach to reduce violence toward a sustainable and just peace that emphasizes human dignity and a common good.Although Catholic peacebuilding institutions attempt to engage at the grassroots,national,and international levels,they can be restricted to local communities in the Himalayas because of political and cultural limitations.Given the importance and plurality of religion,as well as the marginalization of mountain peoples,in the Himalayas,an emphasis on interreligious collaboration to deconstruct oppressive systems of injustice is essential.Despite a problematic colonial past and small minority of Christians in the region,Catholic peacebuilders have demonstrated an ability to contribute when partnering with actors from other faith traditions.Furthermore,Catholic social teaching provides a framework that is helpful to linking political,economic,and social development with efforts toward achieving a just peace.This research will attempt to identify possible opportunities amidst the challenges at the grassroots level and beyond.Catholic peacebuilding,when accounting for the unique challenges of the Himalayas,is one component,among many,that can contribute to local,regional,and global conflict transformation.

The Art of Publishing

This paper＇s goal is to help accounting academics better navigate the editorial review process to increase the likelihood of a manuscript＇s publication. The authors draw on their years of experience as active scholars, reviewers, and editors of academic journals to provide practical insights on manuscript preparation, submission, and revision. Specific topics include （1） selecting an appropriate journal, （2） choosing an appropriate strategy to address a research question, （3） organizing a paper＇s structure including the abstract, motivation section, literature review, implications and conclusions, （4） writing style and （5） revising a manuscript.

Comparison of Silicon Nitride Nanofibers Synthesized Using Silica Nanopowders and Silica Gel

Nanofibers of alpha silicon nitride were grown by a vapor-solid mechanism at 1450?C, through the carbothermal reduction process. Two different precursor silica sources were used: silica nanopowders and silica gel. The effect of processing geometry, particularly the stacking orientations of the graphite substrates, silica pellets, and crucibles, on the density of nanofiber growth was also explored. The silicon nitride nanofibers appear with a predominantly rectangular cross section from silica nanopowder precursors and with a circular cross section for silica gel precursors. Silica gel precursors produce nanofiber products that are smaller in cross section but greater in length than the products from silica nanopowder precursors. The processing geometry must be suitably designed such that the vapor-solid mechanism that is responsible for the formation of the nanofibers is not disrupted.

An Overview of Bidirectional DC-DC Converter Topologies and Control Strategies for Interfacing Energy Storage Systems in Microgrids

A microgrid is defined as a local electric power distribution system with diverse DG （distributed generation） units, energy storage systems, and loads, which can operate as a part of the distribution system or when needed can operate in an islanded mode. Energy storage systems play a key role in improving security, stability, and power quality of the microgrid. During grid-connected mode, these storage units are charged from various DG sources as well as the main grid. During islanded mode, DG sources along with the storage units need to supply the load. Power electronic interfaces between the microgrid buses and the storage units should be able to detect the mode of operation, allow seamless transition between the modes, and allow power flow in both directions, while maintaining stability and power quality. An overview of bidirectional converter topologies relevant to microgrid energy storage application and their control strategies will be presented in this paper.

Gear Fault Detection Using Recurrence Quantification Analysis and Support Vector Machine

This paper presents the application of recurrence plots (RPs) and recurrence quantification analysis (RQA) in the diagnostics of various faults in a gear-train system. For this study, multiple test gears with different health conditions (such as a healthy gear, and defective gears with a root crack on one tooth, multiple cracks on five teeth and missing tooth) are studied. The vibration data of a gear-train is measured by a triaxial accelerometer installed on the test. Two different support vector machine classifiers are trained and compared. Mutual information is used to rank the extracted features in order to select an optimal subset that provides as much information as possible about the intrinsic dynamics of the system. Results indicate that our approach is quite efficient in diagnosing the status of the health of the gear system and characterizing the dynamic behavior.

First Update to Herpetofaunal Records from Timor-Leste

Herpetological surveys of locations in six districts of Timor-Leste(Dili, Baucau, Ermera, Liqui a, Manatuto, Viqueque) during 2010 led to the discovery of a new, high-altitude species of Cryptoblepharus from Ermera District, a new country record(Hemidactylus cf. tenkatei), and the recording of two previously unvouchered species(Python r. reticulatus and Liasis m. mackloti). In this article, we summarize these new records and present numerous new district records for Timor-Leste and four records for road-killed snakes seen in West Timor(Indonesia). With the addition of the results from our 2009 survey, the update presented herein increases the confirmed number of amphibian and reptile species for Timor-Leste to 47.

Herpetological Diversity of Timor-Leste: Updates and a Review of Species Distributions

We report the results of five herpetological surveys during 2011-2013 that included visits to all districts of Timor-Leste （Aileu, Ainaro, Baucau, Bobonaro, Dili, Covalima, Ermera, Laut6m, Liquiga, Manatuto, Manufahi, Viqueque） except the Oecusse exclave. Our fieldwork culminated in the discovery of one putative new frog species （genus Kaloula）, at least five putative new lizard species （genera Cyrtodactylus, Cryptoblepharus, and Sphenomorphus）, and two putative new snake species （genera Stegonotus and Indotyphlops）. In addition, we present new distribution records of amphibians and reptiles for 11 of the country＇s 12 contiguous districts, along with additional natural history data. Results from our surveys increase the number of amphibian and reptiles known to occur in Timor-Leste from 22 species before our surveys began to over 60, including over 20 as yet undescribed species.

Improvement of Renewable Bioenergy Production in Microbial Fuel Cells with Saponin Supplementation

Microbial fuel cell (MFC) is one of renewable biofuel production technology that directly converts biomass to electricity. Cellulosic biomass is particularly attractive renewable resources for its low cost and abundance and neutral carbon balance. However, methanogenesis remains as a major factor limiting MFC performance. The current study reports that saponin addition at 0.05% w/v dose to anolyte in MFCs inhibited methanogenesis and improves power generation and cellulose fermentation. Mediator-less two chamber H-type MFCs were prepared using rumen fluid as anode inocula at 20% v/v of anolyte to convert finely ground pine tree (Avicel) at 2%, w/v to electricity. Saponin was added to the anode of MFC at 0.005% or 0.05% v/v dosage for treatment. MFC power and current across an external resistor were measured daily for 10d. On d10, collected gases from anode compartment were measured for total gas volume and analyzed for gas composition on gas chromatography. Supplementation of saponin to MFC at 0.005% did not have any effects on electricity generation or biogas production and composition. Saponin at 0.05% dose reduced 10% of methane production and increased 40% of CO2 production and 6.4% of total gas production for 10d MFC operation. Voltage across resistor prior to treatment addition (d0) was 164.75 ± 9.07 mV. In control group, voltage across resistor did not change (P = 0.9153) with time course and mean was 167.8 ± 8.20 mV ranged from 157 to 174.5 mV during 10d operation. In 0.05% Saponin group, voltage across resistor increased (P < 0.0001) after d2 and mean was 187.3 ± 4.30 mV ranged between 161.5 and 204.0 mV and the 10d mean of voltage across resistor in 0.05% Saponin was greater (P < 0.0001) than in control group. 0.05% Saponin also had greater voltage across resistor at d5 (P = 0.0030) and d6 (P = 0.0246) than control. End point potential increased (P < 0.0001) in 0.05% Saponin after d2. 0.05% Saponin had greater (P < 0.05) end point potentials than control at d1, d4, d7, d10, and also 10d mean was greater (731.9 vs 606.5 mV;P < 0.0001) in 0.05% Saponin. Power density increased (P < 0.0001) after d2 in 0.05% Saponin. 0.05% Saponin MFCs had greater (P < 0.05) power density than control at d5 and d6, and also a greater (P < 0.0001) overall mean of 10d operation. The current study provides strong background for potential use of saponin and saponin containing natural resources for methanogenesis inhibitor and cellulolysis enhancer in MFC and also cellulolysis reactors.

Mathematical modelling of the spread of COVID-19 on a university campus

In this paper we present a deterministic transmission dynamic compartmental model for the spread of the novel coronavirus on a college campus for the purpose of analyzing strategies to mitigate an outbreak.The goal of this project is to determine and compare the utility of certain containment strategies including gateway testing,surveillance testing,and contact tracing as well as individual level control measures such as mask wearing and social distancing.We modify a standard SEIR-type model to reflect what is currently known about COVID-19.We also modify the model to reflect the population present on a college campus,separating it into students and faculty.This is done in order to capture the expected different contact rates between groups as well as the expected difference in outcomes based on age known for COVID-19.We aim to provide insight into which strategies are most effective,rather than predict exact numbers of infections.We analyze effectiveness by looking at relative changes in the total number of cases as well as the effect a measure has on the estimated basic reproductive number.We find that the total number of infections is most sensitive to parameters relating to student behaviors.We also find that contact tracing can be an effective control strategy when surveillance testing is unavailable.Lastly,we validate the model using data from Villanova University's online COVID-19 Dashboard from Fall 2020 and find good agreement between model and data when superspreader events are incorporated in the model as shocks to the number of infected individuals approximately two weeks after each superspreader event.