this paper presents a novel control method to improve the efficiency of low-voltage dc-dc converters at light loads. pulse width modulation (pwm) converters have poor efficiencies at light loads, while pulse frequency modulation (pfm) control is more efficient for the same cases. switching losses constitute a major portion of the total power loss at light loads. to decrease the switching losses...

Despite the great development in manufacture of helical pile and their use, especially transmission towers wind turbines, there is little research on lateral behavior. In this laboratory study investigate behavior screw piles group (2×1) (1×2) with spacing to diameter helix ratio (S/Dh =1.5, 3, 4.5) having a (10 mm) embedded length (L/D = 40) by using single double soft clay extend stiff under ...

Abstract This work shows that a soft, thin film comprising randomly aligned carbon nanotubes (CNTs) can reduce surface wear more effectively than homogeneous because of enhanced elastic recoverability and contact stress relief originating from its mesh structure. To investigate the characteristics structure compared to those film, multi-walled CNTs (MWCNTs) diamond-like (DLC) films were prepare...

Thin-walled structures like crash boxes may be used as energy absorption members in automotive chassis. There have been many studies addressing the behaviors of energy absorption members on frontal crash. These researches have attempted to predict the energy absorption and maximum impact load in shell structures. The energy absorption and maximum impact load depend on many parameters including ...

The effects of applied load, sliding speed and sliding distance on the dry sliding wear behavior of aged Al-SiCp-Gr composites were investigated. The specimen were fabricated by stir-casting technique. The pin-on-disc wear testing machine was used to investigate the wear rate by design of experiments based on L27 using Taguchi technique. Sliding distance was the most important variable that inf...

in the present work, the simultaneous effects of fuel injection rate and injection of air jet into the combustion chamber on exhaust emissions, combustion process and performance parameters in a direct injection diesel engine were investigated. in order to create an air jet, a design was presented in which a secondary chamber (air cell) was created inside the cylinder and was joined to the main...

The parameters of mill load (ML) not only represent the load of the ball mill, but also determine the grinding production ratio (GPR) of the grinding process. In this paper, a novel soft sensor approach based on multi-spectral segments partial least square (PLS) model and on-line adaptive weighted fusion algorithm is proposed to estimate the ML parameters. At first, frequency spectrums of the s...

This paper presents the design of simple but powerful soft switching scheme for a DCDC Boost Converter with a closed loop control. A new novel soft switching scheme is proposed with a single switch and minimum components which offers load independent operations. The only switch used in this converter is switched ON at zero current and switched OFF at zero voltage .The proposed Controller is use...