Mainstream Outlet Research Articles

Design and Numerical Simulation of Biomimetic Structures to Capture Particles in a Microchannel

The study of separating different sizes of particles through a microchannel has been an interest in recent years and the primary attention of this study is to isolate the particles to the specific outlets. The present work highly focuses on the design and numerical analysis of a microchip and the microparticles capture using special structures like corrugated dragonfly wing structure and cilia walls. The special biomimetic structured corrugated wing is taken from the cross-sectional area of the dragonfly wing and cilia structure is obtained from the epithelium terminal bronchioles to the larynx from the human body. Parametric studies were conducted on different sizes of microchip scaled and tested up in the range between 2–6 mm and the thickness was assigned as 80 µm in both dragonfly wing structure and cilia walls. The microflow channel is a low Reynolds number regime and with the help of the special structures, the flow inside the microchannel is pinched and a sinusoidal waveform pattern is observed. The pinched flow with sinusoidal waveform carries the particles downstream and induces the particles trapped in desired outlets. Fluid particle interaction (FPI) with a time-dependent solver in COMSOL Multiphysics was used to carry out the numerical study. Two particle sizes of 5 µm and 20 µm were applied, the inlet velocity of 0.52 m/s with an inflow angle of 50° was used throughout the study and it suggested that: the microchannel length of 3 mm with corrugated dragonfly wing structure had the maximum particle capture rate of 20 µm at the mainstream outlet. 80% capture rate for the microchannel length of 3 mm with corrugated dragonfly wing structure and 98% capture rate for the microchannel length of 2 mm with cilia wall structure were observed. Numerical simulation results showed that the cilia walled microchip is superior to the corrugated wing structure as the mainstream outlet can conduct most of the 20 µm particles. At the same time, the secondary outlet can laterally capture most of the 5 µm particles. This biomimetic microchip design is expected to be implemented using the PDMS MEMS process in the future.

Hyper-Local Digital News Platforms in Eastern India: A Dynamic Space for Regional Language Media Culture

Abstract “Jumbos are on the road! Before you go out, follow our updates!” No mainstream media outlet would carry such news pertaining to a remote town in Eastern India. However, a hyperlocal news website did. This essay maps the growth of such digital media platforms,whether in the form of websites, YouTube channels or Facebook pages that cater to smalltowns and districts in eastern India. We show how both local journalists and citizens are changing the hyperlocal news culture across Eastern India.

Multiple Mainstreams

Multiple Mainstreams Carla Murphy (bio) Click for larger view View full resolution [End Page 24] I suppose I'm meant to care how "the left" talks about race and class. I fit the profile; I'm a black female journalist. My stories since the early 2000s have featured men and women made invisible or marginalized by society, sometimes by their own communities, and certainly by newsrooms. But as a news gatherer, I've always tinkered on the borderlands of mainstream and progressive journalism, the left's gathering space. I never fully committed. That's because early in my career I settled on an important distinction: it's not how you talk about class and race that matters; it's to and for whom. Audience determines how. Left conversations about race and class rarely center my folks as their audience: the precarious middle-class, working-class, and workingpoor residents of my Brooklyn street; recent immigrants; and native-born Americans like them. Left conversations seem unaware of the value of redistributing news media power such that non-whites and working people construct their own left conversations about race and class. This, to me, is the problem—not how the left's well-educated upper-middle class, unharmed and unbothered by journalism's poverty wages, talks about race and class. As a journalist I always conceived of my role as working for folks who are not in the room. I don't view the progressive or liberal journalist's pursuit of news about marginalized people as progress. From my view in the borderlands, the progressive mission should be to expand the production of news (about race, class, and gender) for these audiences. It should be to create multiple mainstreams strong enough to compete with the mainstream. Producing news about low-wealth people for a better-off, highly educated audience carries a high civic and socioeconomic cost for folks on the losing side of economic inequality and those of us driven to expand democratic participation. It never made sense to me to believe that a shooting in a New York City outer borough has gotten sunlight because a white guy in Greenwich, Connecticut, read about it in an issue of the New York Times. What [End Page 25] does informing him have to do with journalism fulfilling its public service for the people living in that outer borough? Where is their trusted mainstream for surfacing debate, sifting truth from misinformation, and building consensus? I come from city blocks that at one point seemed to be losing one member of every five households to Rikers and to prisons upstate. No mainstream outlet has ever covered that phenomenon commensurate to its effect on generations of families in the sending and receiving zip codes. The affected persons—black, brown, and white—aren't whom those outlets produce news for. Otherwise, we would see newsroom beats like "community health and safety," "justice," or "the prison economy"—instead of "crime." The way that mainstream news media covers healthcare, housing, and higher education, for example, is also shaped by the audience it values. These outlets don't consistently answer the practical, mundane, or even existential questions of people and communities that are low wealth, of color, or immigrant. They answer the white guy in Greenwich's questions. However those outlets talk about race and class, it's for him. They explain the world to him. They center him. They seek to expand his world. They seek to persuade and convince him. They engage and value him. They believe his civic participation matters more than that of the audiences I value. Meanwhile, the nation is browner in real life, and even browner on Gen Z's TV shows and social media. Right now, to paraphrase Ian Haney López, white people are trying to figure out what it means to be white in the United States. For low-wealth families the cost of upward mobility is prohibitive. Is our news system designed for now? It makes sense to me that the journalism industry should serve pluralities, or multiple mainstreams—not only the imagined white, suburban one penning in the black and brown inner-city. That's a throwback to when white...

An approach to runoff modelling in small karst watersheds using the SWAT model

The soil and water assessment tool (SWAT) is one of the most widely used hydrological models. However, it has not been extensively applied in karst watersheds due to their geomorphological heterogeneity. Karst watersheds contribute up to 50% of water supply in Europe, while in South China alone, over 100 million people subsist on it. Hence, improving model performance for karst areas is an important area of research. Here, we propose a methodology based on field investigation and tracer test aimed at improving the conceptual understanding of the hydrological processes to guide the modeller. The Miaogou watershed was used as a case study to run the SWAT model using daily streamflow data from 2013 to 2016. Model calibration and validation results were found to be positive. Average R2 and Nash–Sutcliffe efficiency index (NSE) solutions for the validation period are 0.70 and 0.65 respectively. CN2 was the most sensitive parameter due to the concave shape of the basin as well as the presence of a sinkhole that conveys recharge faster to the main stream outlet via a spring. Our findings show that a field-based approach to modelling karst areas helps define watershed surface and groundwater boundaries, which is often neglected. It also serves as a secondary validation that can be applied anywhere rather than relying on computer code alone. In addition, tracer tests highlight the subterranean hydrological processes which define hydrological gains and losses necessary for model parameterization. Overall, this study establishes a positive outlook towards extensive application in other karstified regions of the world.

Detecting Social Bots on Facebook in an Information Veracity Context

Misleading information is nothing new, yet its impacts seem only to grow. We investigate this phenomenon in the context of social bots. Social bots are software agents that mimic humans. They are intended to interact with humans while supporting specific agendas. This work explores the effect of social bots on the spread of misinformation on Facebook during the Fall of 2016 and prototypes a tool for their detection. Using a dataset of about two million user comments discussing the posts of public pages for nine verified news outlets, we first annotate a large dataset for social bots. We then develop and evaluate commercially implementable bot detection software for public pages with an overall F1 score of 0.71. Applying this software, we found only a small percentage (0.06%) of the commenting user population to be social bots. However, their activity was extremely disproportionate, producing comments at a rate more than fifty times higher (3.5%). Finally, we observe that one might commonly encounter social bot comments at a rate of about one in ten on mainstream outlet and reliable content news posts. In light of these findings and to support page owners and their communities we release prototype code and software to help moderate social bots on Facebook.

Performance Evaluation of Various Rim-Seal Geometries

A numerical investigation has been performed to evaluate the performance of various rim seals in a gas turbine. Two performance functions of the rim seal related to sealing effectiveness and the loss coefficient of the main flow were analyzed for two rim-seal inlet velocities and three leakage fractions using three-dimensional Reynolds-averaged Navier–Stokes equations. The Spalart–Allmaras model was used as the turbulence closure model. The Reynolds number, based on the axial chord at the mainstream outlet, was fixed at 500,000. Computational results for the sealing effectiveness were validated by comparison to experimental data. To examine the effects of the rim-seal configurations on the sealing effectiveness and loss coefficient of the main flow, five different rim-seal geometries were tested. The results indicate that a newly designed rim seal, which includes the inner cavity attached to the rotor side and the narrow interaction plane between the mainstream and rim seal, shows the best performance in sealing effectiveness and loss coefficient among the five tested cases for most of the tested leakage fractions and rim-seal inlet velocities.

Effect of a rib on rim seal performance

The effect of a rib installed in a rim seal on sealing effectiveness was investigated using three-dimensional Reynolds-averaged Navier–Stokes analysis. A parametric study was performed for a single square rib installed on the surface on the rotor side. A total of 12 cases were tested with different heights, widths, and locations of the rib. The Spalart–Allmaras model was adopted as a turbulence closure model. The Reynolds number based on the axial chord of blade was 500,000 at the mainstream outlet. Ratio of the mainstream outlet velocity to mainstream inlet velocity was kept constant at 3.10. The sealing effectiveness was selected as the performance parameter. Installation of a rib in the rim seal enhances sealing performance regardless of the dimensions and location of the rib, although the effects are relatively small in some cases where the rib is located far from the surface of the rim seal on the rotor side.

반원형 리브 혹은 그루브가 부착된 림실에 대한 연구

Effect of semicircular rib or groove on the performance of a rim-seal was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations. The turbulence was modeled using the one-equation Spalart-Allmaras turbulence closure model. Reynolds number based on the axial chord of the turbine blade was 500,000 at the mainstream outlet. The numerical results for a sealing effectiveness was validated in comparison with experimental data. To examine the effect of the semicircular rib or groove on sealing effectiveness of the rim-seal, location and diameter of the rib or groove were selected as the parameters to be performed. The rim-seals with the semicircular groove showed a higher sealing effectiveness than that with the semicircular rib. The semicircular groove installed on the stator side showed best sealing effectiveness among the numerical simulation results.

Security journalism and ‘the mainstream’ in Britain since 7/7: translating terror but inciting violence?

News reporting of terrorism, in the form of security journalism, faces a set of challenges to the functions it serves as a result of both its own practices and the changing practices of news consumers. Security journalism performs some predictable functions, namely the regular delivery of representations of terrorist threats to a presumed national (and international) audience through coverage of Al-Qaeda leaders’ speeches, bomb attempts, criminal trials, and ‘radical’ protests in Britain, among others. Security journalism offers a consistent repackaging of jihadist media productions from one context and language to another. For example, in reducing jihadist texts to short clips of an angry gesticulating man security journalism is prohibiting public understanding of their persuasive potential by cutting any political, religious or sensual appeals. This article presents original data from interviews with British Muslims familiar with jihadist materials that suggest mainstream media reporting may contribute to radicalization in ways not sufficiently appreciated by journalists, policy-makers and the public. Interviewees report that any news depicting Muslim suffering activates and reinforces frustrations and grievances, whether the source is a mainstream media outlet or Al-Qaeda's media wing. Mainstream media may unintentionally contribute to a more enduring but diffused resentment a priori to the existence of jihadist media; as one participant says, ‘I am already convinced’.