A Case of Problematic Diffusion

Sex determination techniques have diffused rapidly in India, and are being used to detect female fetuses and subsequently to abort them. This technology has spread rapidly because it imparts knowledge that is of great value within the Indian context, and because it fits in neatly with the modernization dynamic within India, which itself has enmeshed with traditional patriarchal institutions to oppress Indian women. More research needs to be done on ways to stem the adoption of problematic innovations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68396/2/10.1177_107554709401500301.pd

Open data from the third observing run of LIGO, Virgo, KAGRA, and GEO

The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages

Wavelet analysis of finite height grid turbulence over a flat plate

An experimental investigation was carried out in a wind tunnel in order to study the turbulent flow over a flat plate that is a scaledown of a photovoltaic (PV) panel. By inducing turbulence in the flow over a PV panel, its convective heat loss can be increased. The turbulence was generated by a plate with diamond-shaped perforations (grid), which was mounted vertically at the leading edge of the flat plate. Fourier and wavelet transforms are utilized to study the turbulence downstream of the grid at specific points. Results showed that at the height of the upper edge of the grid, turbulence has a higher kinetic energy than at the points behind the grid. For the points behind the grid, at all eddy size ranges, turbulence energy decayed significantly with downstream distance. For the points at grid height, it seems that for large eddies (frequency lower than 100 Hz) the energy increased in the downstream direction and for other ranges it decreased very slightly. This analysis may influence the design of passive flow devices meant to enhance the heat transfer from a PV panel\u27s surface

Turbulent flow over a flat plate downstream of a finite height perforated plate

An experimental investigation was carried out to study the turbulent flow over a flat plate in a wind tunnel. The turbulence was generated by a plate with diamond-shaped perforations mounted perpendicular to and on the leading edge of the flat plate. Unlike conventional grid turbulence studies, this perforated plate had a finite height, and this height was explored as a key independent parameter. Instantaneous velocity measurements were performed with a 1D hot-wire anemometer to reveal the behavior of the flow a short distance downstream of the perforated plate (X/D = 10-30). Different perforated plate heights (H = 3, 7, 11 cm) and free stream velocities (U = 4.5, 5.5, 6.5 m/s) have been studied

Effect of a Triangular Rib on a Flat Plate Boundary Layer

The flow structure downstream of a triangular rib over a thin plate placed in a wind tunnel was experimentally investigated using a boundary layer hotwire anemometer. Flow and boundary layer characteristics, such as thickness, shape, and turbulence parameters, were studied at different freestream velocities and streamwise locations corresponding to ReX of 1.7 × 104-2.8 × 105 for plates without and with a leading edge rib. It was found that the boundary layer of the flow over a ribbed wall was 3-3.5 times thicker and had higher turbulence intensity and smaller turbulence length scales compared to its smooth wall counterpart

Community solar PV projects

In today’s world, global warming (GW) and the resulting climate change are a significant threat to humans, plants and animals. The main contributor to GW is greenhouse gases (GHGs) that are created from the burning of fossil fuels, mainly for electrical power. Hence, the way forward in safeguarding the future of life on planet earth is to reduce on our GHG emissions and move rapidly to the utilization of renewable energy resources that are abundantly available. There are numerous advantages in implementing renewable energy projects versus the use of fossil fuels in meeting individual or community energy demands. With renewable energy, an individual or community will be able to have a more diverse and stable long-term energy supply, considering fossil fuel resources are slowly being depleted. Small-scale renewable energy projects, especially in remote communities which are currently served by diesel-generated electricity, offset the community’s use of diesel fuel. Although there will be times when renewable energy is not available and a back-up source of power is required, the long-term cost of energy may be reduced. And the use of indigenous energy can contribute to a nation (or region’s) energy security by significantly reducing its dependence on imported oil (assuming it is not an oil exporter). There are numerous renewable energy resources available globally (wind, solar, biomass, falling water, geothermal) that can be used for individual or community energy projects. Community energy projects are distinguished from other renewable energy projects in which members of the community are subscribers who use the electricity produced by the project, even though each individual does not solely own the equipment. This chapter presents an overview of how energy captured from the sun can be utilized at the community level by installing solar photovoltaic systems in the form of a solar garden or solar farm or solar power plant to generate electrical energy in meeting some, if not all, of the community total energy demand. In addition, readers will be exposed to three common ownership models and their benefits, barriers affecting the adoption of such projects and selected examples of such projects that have been completed or are in the conceptualization or construction phase within North America, Europe, South America and East Africa