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Number of results: 5
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Abstract

Ultrasonic pulse echo technique was used to study cupric oxide (CuO) thin films. CuO thin films were prepared using sol gel technique. They were doped with Lithium (Li) (1%, 2% and 4%).

Thin films’ thickness (d) and band gap energy (Eg) were measured. In addition, elastic moduli (longitudinal (L), shear (G), bulk (K) and Young’s (E)) and Poisson’s ratio (v) were determined to estimate the microstructure properties of the prepared films.

The study ameliorated the used transducers to overcome their dead zone and beam scattering; wedges were developed. The results showed the effectiveness of these wedges. They enhanced transducers’ sensitivity by changing the dead zone, beam diameter, beam directivity and waves’ transmission.

Also, the study noted that Li doping caused the improvement of CuO thin films to be more useful in solar cell fabrication. Li-CuO thin films had narrower band gap. Thus, they acquired a high quantum yield for the excited carriers; also they gained more efficiency to absorb solar light.

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Authors and Affiliations

Barakat Mirham Abdallah Youssef
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Abstract

This paper presents the results of research into the cross wedge rolling (CWR) process of axle forgings. The presented results concern the parallel rolling process with two wedges. The use of two parallel wedges is aimed at shortening the tool length (increasing productivity) and reducing the values of wedge opening angles and increasing the forming angles, so that the condition 0.04 ≤ tgαtgβ ≤ 0.08 is maintained to guarantee the highest quality forgings. The article analyses the influence of the design of the double wedge tool on the geometric correctness of the forgings obtained, the value of the failure criterion and the force parameters of the process. The results obtained show that the use of multi wedge tools improves rolling conditions by increasing productivity and reducing the tendency of the material to crack with appropriately selected tool parameters.
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Authors and Affiliations

T. Bulzak
1
ORCID: ORCID

  1. Lublin University of Technology, Faculty of Mechanical Engineering, Department of Metal Forming, 36 Nadbystrzycka Str., 20-618, Lublin, Poland
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Abstract

This article presents a case study of a large wedge failure. It took place during excavation of the last bench of storage cavern with an approximate dimension of 80 m long having a depth of 8 m. The adopted intervention followed a structured approach, which included immediate rock support, geotechnical and geological investigations in the failure zone and design modifications. Back analyses of the failure zone were also carried out to assess design parameters with observed geological conditions. Re assessment in the failure zone was carried out using modified design parameters, which included shorter benches, rock support installation schemes such as longer rock bolts, reinforced ribs of shotcrete and reduced construction advances. Geotechnical monitoring in and around failure zone were carried out for recording any alarming movements in the rock mass. Initially, geotechnical monitoring was carried out in the recently excavated zone of the cavern on a daily basis. Based on continuous monitoring data for at least one week, the frequency of subsequent monitoring can be decided. In most cases the deformation of rock mass was considerably less than the alarming values which were calculated based on detailed design for different rock classes. The paper discusses the failure, investigation, cause, assessment and remedial measures to complete the construction of cavern.

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Authors and Affiliations

Tejas Bhatkar
Altaf Usmani
Anirban Mandal
Atal Nanda
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Abstract

A sound knowledge of horseshoe impact on blood flow parameters is required for making shoeing decisions and selecting the most appropriate types of shoes. The aim of this study was to determine the effect of horse shoeing with egg bar shoes and shoes with wedge pads on blood flow parameters in the lateral palmar digital artery measured by Doppler ultrasound. The study was conducted on 16 horses divided into two groups. Horses from group 1 were shod with egg bar shoes. Horses from group 2 were shod with shoes with wedge pads. Doppler ultrasound parameters of the lateral palmar digital artery at the level of the metacarpophalangeal joint were evaluated. Doppler tests were performed before and after shoeing within a monthly interval. The results of the study indicate that egg bar shoes have a greater impact on blood circulation in the distal part of the equine limb than shoes with wedge pads. However, the only parameters to have changed substantially after shoeing with egg bar shoes were end-diastolic velocity (EDV) and mean velocity (Vmn) in the lateral palmar digital artery. A low-resistance blood flow pattern was noted before shoeing. After shoeing in group 1, it remained unchanged in 5 horses, whereas a high-resistance pattern was observed in 3 animals. A low-resistance blood flow pattern was noted in all group 2 horses after shoeing. The difference between the analyzed shoeing techniques could be attributed to increased pressure in the heel bulb area in horses shod with egg bar shoes. Wedge pads shift the load away from the heel bulbs, which might reduce the pressure on the palmar digital vessels and exert a smaller influence on the parameters measured in the Doppler ultrasound test.
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Authors and Affiliations

M. Mieszkowska
1
P. Holak
1
Y. Zhalniarovich
1
M. Mieszkowski
2
K. Domagalska-Stomska
3

  1. Department of Surgery and Radiology with Clinic, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 14, Olsztyn, 10-719, Poland
  2. Department of Anesthesiology and Intensive Care, Faculty of Medicine, Collegium Medicum, University of Warmia and Mazury in Olsztyn, Al. Warszawska 30, 10-082, Olsztyn, Poland
  3. Student of 5th year, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 14, Olsztyn, 10-719, Poland
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Abstract

City parks play a very important role in an urbanized landscape. They are forms of specially designed green space which combine elements of horticulture with architecture, history and culture. The article presents historical urban parks and old residential-park complexes included in the boundaries of Poznań and currently existing in the wedge-ring system of the urban green space. The aim of the conducted research was to show their historical and current function as well as their general state of preservation and condition. The results are presented in the form of a Table where the historical significance of those objects is compared with their role today.

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Authors and Affiliations

Agnieszka Rosada
Miłosz Walerzak
Piotr Urbański

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