Characterising the effect of laser power on laser metal deposited titanium alloy and boron carbide

Abstract: Titanium alloy has gained acceptance in the aerospace, marine, chemical and other related industries due to its excellent combination of mechanical and corrosion properties. In order to augment its properties, a hard ceramic, boron carbide has been laser cladded with it at varying laser powers between 0.8 kW and 2.4 kW. This paper presents the effect of laser power on the laser deposited Ti6Al4V-B4C composites through the evolving microstructures and microhardness. The microstructures of the composites exhibit the formation of α-Ti phase and β-Ti phase and were elongated towards the heat affected zone. These phases were terminated at the fusion zone and globular microstructures were found growing epi! taxially just immediately after the fusion zone. Good bondings were formed in all the deposited composites. Sample A1 deposited at a laser power of 0.8 kW and scanning speed of 1 m/min exhibits the highest hardness of HV 432±27 while sample A4 deposited at a laser power of 2.0 kW and scanning speed of 1 m/min displays the lowest hardness of HV 360±18. From the hardness results obtained, ceramic B4C has improved the mechanical properties of the primary alloy

Effect of punch diameters on shear extrusion of 6063 aluminium alloy

This paper reports the effect of punch diameters on the shear extrusion of 6063 Aluminium alloy. During the shear extrusion process, Aluminium billets of considerable diameter 30 mm and height 25 mm were inserted in a die hole and different punches of diameter 12 mm, 14 mm, 16 mm and 18 mm respectively were allowed to come in contact to perform the shear operation. The setup took place under a hydraulic press with maximum capacity of 600 kN. This work is aimed at studying the selection of the optimum punch diameter for shear extrusion using local groundnut oil as the lubricant. Different extrusion pressures were measured and the punch with a diameter of 18 mm gives the highest load of 77.7 kN while the punch with a diameter of 12 mm gives the lowest load of 51.2 kN. An indication shows that, an increase in the punch diameters led to an increase in the height of the extrudates and this in turn reduces the stress induced

Characterising the effect of laser metal deposited Ti6Al4V/Cu composites in simulated body fluid for biomedical application

Ti6Al4V alloy has been known to have very excellent corrosion resistance due to the oxide layer formed on its surface. Due to this property, the alloy is found applicable for biomedical implants. Copper shows an excellent antimicrobial property and has been found to stabilize the immune system. In this study, laser metal deposition of Ti6Al4V powder and Cu powder on Ti6Al4V substrates were conducted by varying the laser power between 600 W and 1800 W while the scanning speed, the powder flow rate and the gas flow rate were kept constant. The surface behaviour and the morphologies of the composites were evaluated under the microscope and the SEM after soaking for 4 hours, 5 days and 2 weeks respectively. The simulated body fluid (hank’s solution) was maintained at normal body temperature of about 37±1oC. The surfaces showed fracture topography with porous bone-like structures and some trivial pitting were observed

Characterization of surface roughness of laser deposited Titanium alloy and copper using AFM

Abstract: Laser Metal Deposition (LMD) is the process of using the laser beam of a nozzle to produce a melt pool on a metal surface usually the substrate and metal powder is been deposited into it thereby creating a fusion bond with the substrate to form a new material layer against the force gravity. A good metal laminate is formed when the wettability between the dropping metal powder and the substrate adheres. This paper reports the surface roughness of laser deposited titanium alloy and copper (Ti6Al4V + Cu) using the Atomic Force Microscopy (AFM). This AFM is employed in order to sense the surface and produce different manipulated images using the micro-fabricated mechanical tip under a probe cartridge of high resolution. The process parameters employed during the deposition routine determines the output of the deposit. A careful attention is given to the laser deposited Ti6Al4V + Cu samples under the AFM probe because of their single tracked layers with semi-circular pattern of deposition

Destructive fishing: An expert-driven definition and exploration of this quasi-concept

Data availability statement: Data that breaches the anonymity of responses in this study cannot be made available. Some anonymised and summary data can be found in the Supplementary Information.Data Availability Statement: Data that breaches the anonymity of responses in this study cannot be made available. Some anonymized and summary data can be found in the Supplementary Information.Code Availability Statement: Code for the figures and certain analyses used in this manuscript can be found at https://github.com/arlie-m/destructive_fishing_defintion_delphi.Supporting Information is available online at: https://conbio.onlinelibrary.wiley.com/doi/10.1111/conl.13015#support-information-section .Numerous policy and international frameworks consider that “destructive fishing” hampers efforts to reach sustainability goals. Though ubiquitous, “destructive fishing” is undefined and therefore currently immeasurable. Here we propose a definition developed through expert consultation: “Destructive fishing is any fishing practice that causes irrecoverable habitat degradation, or which causes significant adverse environmental impacts, results in long-term declines in target or nontarget species beyond biologically safe limits and has negative livelihood impacts.” We show strong stakeholder support for a definition, consensus on many biological and ecological dimensions, and no clustering of respondents from different sectors. Our consensus definition is a significant step toward defining sustainable fisheries goals and will help interpret and implement global political commitments which utilize the term “destructive fishing.” Our definition and results will help reinforce the Food and Agricultural Organization's Code of Conduct and meaningfully support member countries to prohibit destructive fishing practices.Cambridge Conservation Initiative. Grant Number: CCI-05-20-009; Helmholtz Institute for Functional Marine Biodiversity (HIFMB) at the University of Oldenburg; Brunel University London; Alfred-Wegener-Institute for Polar and Marine Research; Arcadia; Rothschild Foundation; A.G. Leventis Foundation; Isaac Newton Trust; Prince Albert II of Monaco Foundation

Destructive fishing : an expert‐driven definition and exploration of this quasi‐concept

Numerous policy and international frameworks consider that “destructive fishing” hampers efforts to reach sustainability goals. Though ubiquitous, “destructive fishing” is undefined and therefore currently immeasurable. Here we propose a definition developed through expert consultation: “Destructive fishing is any fishing practice that causes irrecoverable habitat degradation, or which causes significant adverse environmental impacts, results in long-term declines in target or nontarget species beyond biologically safe limits and has negative livelihood impacts.” We show strong stakeholder support for a definition, consensus on many biological and ecological dimensions, and no clustering of respondents from different sectors. Our consensus definition is a significant step toward defining sustainable fisheries goals and will help interpret and implement global political commitments which utilize the term “destructive fishing.” Our definition and results will help reinforce the Food and Agricultural Organization's Code of Conduct and meaningfully support member countries to prohibit destructive fishing practices

Dismissione, riuso, risorsa. Il Palazzo di Giustizia di Salerno

The design of the city of Salerno stems from the expansion programs of the last century that already defined starting from the end of nineteenth century and which were fully implemented in the period between the two world wars. To cope with the changed demand for spaces and structures, by resulting from an extraordinary population growth and the different functions that the new century required, during this period were built in Salerno almost all public buildings including the Justice Palace destined to bring together “with decorum and dignity” all the judicial offices present in the city. The construction of the Justice Palace in Salerno began in 1929 with the inclusion of the project into the “extraordinary public works” program and ended with its inauguration in 1939. During this period Salerno tested new building technologies related to the use of reinforced concrete and in the Justice Palace, example of a monumental and passatist architecture, there are some of the more advanced techniques and patents for the realization of reinforced-concrete floors. Following the construction of the new Judicial Citadel designed by David Chipperfield, the ancient building is currently being decommissioned and therefore it is necessary to define the criteria for a reconversion able to protect its historical and material characteristics