Aeration experiments were conducted in two rectangular surface aeration tanks of L/B ratios 1.5 and 2 along with a square tank (L/B=1) to study their relative performance due to shape on oxygen transfer process while re-aerating the same volume of water such that the cross-sectional area of all the three tanks is the same. An identical rotor with six flat blades was used in all the three tanks....

Friction welding of cast Fe-40Al alloy was carried out at 1000 rmp for various friction times, friction pressures, and forging pressures. The microstructures of the interface of welded samples were analyzed by optical and scanning electron microscopy (SEM). Micrographs demonstrated that excellent welding formed continuously along the interface, except for samples welded for 3 s. Chemical compos...

As a new treatment process after welding, the process parameters of laser shock peening (LSP) in dynamic strain aging (DSA) temperature regimes can be precisely controlled, and the process is a non-contact one. The effects of LSP at elevated temperatures on the distribution of the surface residual stress of AA6061-T6 welded joints were investigated by using X-ray diffraction technology with the...

Engineering fatigue fracture failure is one of the most common phenomena of mechanical and structural failure, statistically representing approximately 50 to 90% of total mechanical damage [1]. Lattice structures have been widely used in crane booms, steel plants, parking garages, offshore platforms and other fields [2] to [4]. In a crane, the lattice boom has better mechanical properties compa...

This study investigated the joint properties of Fe-Pt alloy laser-welded to Co-Cr alloy. Cast plates (0.5 x 3.0 x 10 mm) were prepared with Fe-Pt and Co-Cr alloys. Fe-Pt plates were butted against Co-Cr plates and laser-welded using Nd:YAG laser. Control and homogeneously welded specimens were also prepared. Laser welding was performed with and without argon shielding. Tensile testing was condu...

dissimilar metals friction welding of austenitic–martensitic stainless steels is commonly used in order to manufacture engine valves in the automobile industry. in this study, x53crmnnin219 (austenitic stainless steel) and x45crsi93 (martensitic stainless steel) valve steel rods were welded by friction welding process. the welded joint was then heat treated at 760 0c for 60 min. mechanical prop...

In this study, 7075 aluminum alloy with a thickness of 10 mm was successfully welded with no obvious defects by pulsed variable polarity plasma arc (PVPPA) welding. The mechanical properties of PVPPA welded joints have been researched by post weld heat treatment (PWHT). The results indicate that the heat treatment strongly affects the mechanical properties of the welded joints. The tensile stre...

Ultrasonic peening treatment (UPT) as a method of severe plastic deformation was used to treat cruciform welded joints of Q345 steel. The application of UPT achieves material surface nanocrystallization of the peening zone, reduces stress concentration, and produces residual compressive stresses at the welded toe. Micro-structure, hardness, stress relief, S-N curve, and the fatigue fracture mec...

This study examines the pressures which lead to employers offering low-paid, insecure jobs and also considers the scope for change. Employers determine terms and conditions and how work is organised, including pay, the balance between temporary and permanent work, skill requirements and progression structures. In seeking to reduce intermittent poverty, it is, therefore, important to consider ho...