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Effect of Low Power CW Laser (He-Ne)on Artemia Cyst
, M.Sc. Thesis Sharif University of Technology ; Sadighi Bonabi, Rasoul (Supervisor)
Abstract
Artemia (brine shrimp) is a genus of crustaceans that lives in saltwater and due to having unique features, in producing the food and nutrients needed for larvae and other types of farmed sea creatures, is of great importance. In its natural environment under certain conditions, Artemia produces cysts that float at the water surface and are driven ashore by wind and waves. These cysts are inactive and do not develop further as long as they are kept dry. Upon immersion in seawater, the biconcave cysts hydrate and become spherical and, within the shell, the embryo resumes its interrupted metabolism. After about 20 h the outer membrane of the cyst breaking and the embryo appears, surrounded by...
The effect of irradiating photon on biological qualities of Artemia/Artemia cysts
, M.Sc. Thesis Sharif University of Technology ; Sadighi Bonabi, Rasoul (Supervisor) ; Ghaeni, Mansooreh (Co-Advisor)
Abstract
Artemia is a small crustacean which has adapted to live in high salty water.The name of Artemia has been chosen according to its appearance. The adult Artemia is viviparous in the proper conditions whereas in tough conditions it reproduces the cysts. About 20 hours after the floating of cysts in water, its crust splits and after a while nauplii is produced by the free swimming. The changes of the hatching percentage of cysts Artemia and also the changes of Artemia Urmiana's size have been evaluated in this report.
The hatching percentage of cysts have been studied under LED radiation of red, orange, green and blue wavelengths, under red diode laser radiation and also under the...
The hatching percentage of cysts have been studied under LED radiation of red, orange, green and blue wavelengths, under red diode laser radiation and also under the...
Optimization of Scan Algorithms in Selective Laser Sintering
, M.Sc. Thesis Sharif University of Technology ; Movahhedi, Mohammad Reza (Supervisor) ; Khodaygan, Saeed (Supervisor)
Abstract
One of the most important manufacturing methods using technologies AM, is the SLS method. This method because it would significantly reduce the construction time is the ability to build a variety of materials, is pervasive. The SLS devices input is part CAD file which is then part layered, a layer of powder is poured on the bed. Each layer is defined contour on the part and then scanned by laser inner layer is hatched by laser. Scanning algorithms and hatching in the SLS is an important part of building that has an impact on properties part and a lot of research has been done about it. synthetic scan algorithms presented in this study. The purpose of this algorithm is that part warpage and...
Additional slag doors for increased EAF efficiency: A conceptual study
, Article ISIJ International ; Volume 57, Issue 8 , 2017 , Pages 1394-1399 ; 09151559 (ISSN) ; Fathi, A ; Skrjanc, I ; Logar, V ; Sharif University of Technology
Iron and Steel Institute of Japan
2017
Abstract
The paper presents a conceptual study on modification of the electric arc furnace (EAF) slag doors in order to allow removal of the excess slag from the EAF. The idea behind additional slag doors is to allow deslagging of the bath in certain unfavorable cases when the slag height is too great. Slags which exceed the optimal height cause unnecessary refractory corrosion and additional energy losses. The study proposes symmetric slag doors comprised of two hatches, i.e. upper and lower. The upper hatch is intended to decrease the slag height to the optimal level, while the lower hatch can be used to completely deslag the EAF at tapping. In this manner, tilting of the EAF is not necessary. A...
An efficient scanning algorithm for improving accuracy based on minimising part warping in selected laser sintering process
, Article Virtual and Physical Prototyping ; Volume 14, Issue 1 , 2019 , Pages 59-78 ; 17452759 (ISSN) ; Movahhedy, M. R ; Khodaygan, S ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
In the selective laser sintering (SLS) method, layers of powder are scanned by a laser beam and sintered. The thermal gradients created by laser heating and the subsequent cooling of the sintered sections results in thermal stresses and part warping in the final part. Thermal gradients are dependent on the scanning algorithm, in particular, the scan vector length. In this work, an efficient scanning algorithm for the SLS process is presented with the aim to minimise the part warping in the final part due to thermally induced residual stresses, while maintaining the production time at a minimum. The proposed algorithm is implemented in a finite element simulation and scanning parameters...