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Introduction of Computer Networks
Published in Dijiang Huang, Ankur Chowdhary, Sandeep Pisharody, Software-Defined Networking and Security, 2018
Dijiang Huang, Ankur Chowdhary, Sandeep Pisharody
Below the network interface layer is the transmission medium, through which actual communication occurs. The receiver will process data in the reverse order as done by the sender, called decapsulationDecapsultion, to remove added headers at each layer, and finally reveal the message to the messaging application. The peer process abstraction is crucial to all network design. Using the layered approach, a basic principle is to ensure the independence of layers by defining services provided by each layer to the next higher layer without defining how the services are to be performed. This permits changes in a layer without affecting other layers.
ClarisWorks
Published in Paul W. Ross, The Handbook of Software for Engineers and Scientists, 2018
Every object you create is in a separate layer with the bottom layer being the first object created. Objects can be laid one above the other and still be seen as the layers are transparent. Objects can be moved up and/or down through the layers by using the move commands under the Arrange menu.
Power loss due to soiling on photovoltaic module with and without anti-soiling coating at different angle of incidence
Published in International Journal of Green Energy, 2021
Bushra Mahnoor, Muhammad Noman, Muhammad Saad Rehan, Adnan Daud Khan
Another important factor which negatively influences the performance of a PV module is the soiling which arises due to the accumulation of dust on the glass (Mani and Pillai 2010; Naeem and Tamizhmani 2016) Soiling hinders the amount of light reaching the solar panel and ultimately reduces the performance of PV arrays by blocking a certain fraction of incident sunlight on the module. It limits the accessibility of photons to the solar cell which reduces the production of charged particles and in turn reduces the ISC (Jim Joseph John, Tatapudi, and Tamizhmani 2014). Therefore, the effect of soiling on the losses associated with the solar incidence angle also needs to be taken into account. Several studies have been carried out which determined the spectral and AOI associated losses that occur in PV modules due to the formation of soil layer (Alquthami and Menoufi 2019; García et al. 2011; Zorrilla-Casanova et al. 2011). This layer can be treated as partially opaque and partially transparent. The incident light is either completely blocked by the soil or transmitted to the glass due to soil porosity. The light reaching the glass superstrate at any AOI depends upon both the transparent and opaque nature of the soiling layer with the opaque nature of soil more dominant at higher AOI (Jim J. John et al. 2015). The incident sunlight is both attenuated and scattered by the obstruction of the dust particles. This scattering depends upon the size, shape and composition of the dust particles, the AOI, and the soiling density. The AOI is called the “critical AOI” when a power loss of 3% or more occurs as compared to the loss at 0° incident angle. When the AOI is greater than the critical angle, then along with the geometric losses or cosine losses, reflection losses also occur. The same study also revealed that the critical angle is about 57° for unsoiled polycrystalline silicon PV modules which reduces with soiling density on the module. It is about 42°, 38°, and 20° for lightly, medium and heavily soiled PV modules respectively. Experimental studies on soiled polycrystalline silicon technology revealed that the thickness of soil layer and effects of AOI are in proportion to each other (John et al. 2014). Losses due to soiling can be mitigated by using anti-soiling coatings on PV (Quan and Zhang 2017; Ravi et al. 2019). These coatings are anti-reflective as well as self-cleaning. The soiling losses are higher for the modules without anti-soiling coatings. Coated modules have a daily average soiling loss of 2.5% as compared to 3.3% of uncoated modules (Piliougine et al. 2013).