On the Variable Acceleration Motion of Falling Sphere in a Fluid Medium
Issue:
Volume 11, Issue 2, March 2023
Pages:
31-39
Received:
16 March 2023
Accepted:
10 April 2023
Published:
27 April 2023
Abstract: Falling motion of a sphere in the stationary medium is an important basic research and has a wide range of engineering application prospects. This paper studies the free fall motion of spheres in a stationary medium considering air drag. This paper calculates the acceleration, velocity and displacement of the falling process of the sphere by Excel, and discusses the influence of the density, diameter and Re on the motion. Some analysis and fitting of displacement over time are performed. The results show that the varied-acceleration motion of the falling spheres is similar for different sphere materials, namely, the falling acceleration, the velocity and falling displacement all can be divided into three segmentations and fitted with polynomial functions. The relationship between displacement h and time t during falling with varied- acceleration is also greatly affected by the density of the sphere, the greater the density of the sphere, the closer the relationship between h and t during the fall process is closer to no drag free fall, the smaller the density of the sphere is, the closer the relationship between h and t is nearer to linear relationship. The displacement data of different solid material sphere is located between the fall of water and the free drop without drag, but does not meet power function or the multi-relationship function. Some results are compared with the literature experiments, and are consistent with the experiments.
Abstract: Falling motion of a sphere in the stationary medium is an important basic research and has a wide range of engineering application prospects. This paper studies the free fall motion of spheres in a stationary medium considering air drag. This paper calculates the acceleration, velocity and displacement of the falling process of the sphere by Excel,...
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Thermal Annealing Effect on Optical and Electrical Properties of Zinc Selenide (ZnSe) Thin Films
Esubalew Yehualaw Melaku,
Tizazu Abza Abshiro,
Wubamlak Nigussie
Issue:
Volume 11, Issue 2, March 2023
Pages:
40-46
Received:
2 May 2023
Accepted:
2 June 2023
Published:
29 June 2023
Abstract: The impact factor of ZnSe thin films in an aqueous solution of zinc acetate and hydrazine hydrate (HH) using the non-toxic complexing agent EDTA along with the films were annealed at 200, 300, and 400°C. This research aimed to employed XRD analysis, optical measurements, and electrical resistivity measurements to study the ZnSe thin films, respectively. The use of these complementary techniques allowed for a compressive understanding of the effect of annealing on the physical properties of the films. The ZnSe thin films are annealed in an oven at various temperatures which are characterized by structural and optical properties. An increase in annealing temperature distorted the nanocrystillinity and made the ZnSe thin films amorphous. The variation of resistivity indicates the semiconducting nature of the thin film. The electrical resistivity of the films decreases with increasing annealing temperature. In this study, the Band gap of ZnSe decreases from 2.8eV to 2.65eV with the increase in temperature and decreases for as-deposited to 2.5eV. As a result of this research ZnSe is used for certain applications, it has been widely utilized in various optoelectronic devices such as thin film solar cells, green-blue light emitting diodes, lasers, photo-luminescent, and electro-luminescent devices.
Abstract: The impact factor of ZnSe thin films in an aqueous solution of zinc acetate and hydrazine hydrate (HH) using the non-toxic complexing agent EDTA along with the films were annealed at 200, 300, and 400°C. This research aimed to employed XRD analysis, optical measurements, and electrical resistivity measurements to study the ZnSe thin films, respecti...
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