Abstract: This study presents the design and fabrication of a novel wood-fired commercial oven for baking bread. The oven design features an external combustion chamber with heating elements which comprise stainless-steel pipes filled with magnesia starting from the combustion chamber to the 3 oven compartments. Each compartment has 12 heating elements laid under a mild steel sheet metal where the dough mould and its content is placed. Heat loss due to conduction, radiation and convection was prevented by the use of a double wall in both oven and combustion chamber compartments with silica brick and fibre glass respectively, and the oven was fired with wood to bake some dough. Findings showed that maximum temperature attainable by the oven was 700°C, however, the temperature required for baking bread is between 150°C and 180°C and the time was 25 minutes, the quantity of heat generated per time using 10 kg of wood was about 15,088 KJ. Furthermore, the physical appearance of the products was examined to meet consumers’ requirement and a total of 400 bread of 180 mm × 120 mm × 80 mm dimensions can be baked at a time. With slight modifications in the oven design, this number can be improved. The oven can be fired with other types of solid biofuels and can be used for metallurgical furnace applications like annealing, tempering and other heat treatments of metals.
Abstract: This study presents the design and fabrication of a novel wood-fired commercial oven for baking bread. The oven design features an external combustion chamber with heating elements which comprise stainless-steel pipes filled with magnesia starting from the combustion chamber to the 3 oven compartments. Each compartment has 12 heating elements laid ...Show More
Abstract: This study investigates the dynamic behavior of a quasi-zero stiffness (QZS) vibration isolator integrated with shape memory alloy (SMA) springs to achieve enhanced vibration isolation performance. QZS isolators are designed to mitigate vibrations effectively in low-frequency environments by combining linear and nonlinear stiffness elements to achieve a near-zero effective stiffness around the equilibrium position. The inclusion of SMA springs introduces unique properties such as shape memory effect and pseudoelasticity, enabling tunable stiffness and damping characteristics.. A comprehensive mathematical model of the isolator is developed, incorporating the nonlinear force-displacement behavior of the SMA spring based on thermomechanical coupling and constitutive relations. The dynamics of the system are analyzed under harmonic and random excitation, and key parameters influencing isolation performance, such as temperature, pre-compression of the SMA spring, and system damping, are systematically explored. Numerical simulations reveal that the SMA-based QZS isolator exhibits superior vibration attenuation compared to traditional isolators, with the added benefit of adaptability to changing operational conditions. It is demonstrated that the resonant frequency of the proposed isolation system is near zero. Numerical simulations are carried out, and the influence of the excitation amplitude and frequency on vibration isolation are studied. It is shown that a quasi-zero dynamic stiffness is achieved; hence the feasibility of the proposed system for low-frequency excitation isolation is validated.
Abstract: This study investigates the dynamic behavior of a quasi-zero stiffness (QZS) vibration isolator integrated with shape memory alloy (SMA) springs to achieve enhanced vibration isolation performance. QZS isolators are designed to mitigate vibrations effectively in low-frequency environments by combining linear and nonlinear stiffness elements to achi...Show More