In order to improve the impact performance, the structure of hydraulic hammer should be optimized. In this paper, the ranges of eight vital structure parameters of piston and reversing valve system of hydraulic hammer were selected firstly; and then found the best value of different parameters under experiments with the method of computer optimization and the parametric analysis method provided...

A concert pianist is able to produce a wide range of imaginable nuances of musical expression by actuating the 88 keys on a piano, none of which travel through a distance greater than one centimeter. In this study, we investigated the temporal behaviour of grand piano actions from different manufacturers using different types of touch (‘legato’ versus ‘staccato’). An experimental setup consisti...

We establish a generic theoretical tool to construct probabilistic bounds for algorithms where the output is a subset of objects from an initial pool of candidates (or more generally, a probability distribution on said pool). This general device, dubbed “Occam’s hammer”, acts as a meta layer when a probabilistic bound is already known on the objects of the pool taken individually, and aims at c...

Dynamic Pressure rise or fall in all kinds of pipelines due to the operation valve which are transmitting fluids very much essential part consider design pipeline. This paper presents how calculate these dynamic pressure waves while designing pipelines.

In this paper, the piston rebound common to both the Schmidt Impact Hammer and downhole hammer drills has been analyzed and calculated by means of stress wave theory and the energy conservation law. A quantitative relationship between the amount of rebound of the piston and the impact resistance index, or hardness of the rock, has been established. Those analytical results will not only be of b...

The input admittance at the bridge, measured by hammer testing, is often regarded as the most useful and convenient measurement of the vibrational behavior of a bowed string instrument. However, this method has been questioned, due especially to differences between human bowing and hammer impact. The goal of the research presented here is to investigate the reliability and accuracy of this clas...

Currently, in civil engineering, high performance concrete i.e. concretes whose minimum compression strength is equal or more than 65 MPa are increasingly used. Side effect of it is need for determination of their construction strength. In particular, recently built high performance structures suffer from sampling of drill cores. Therefore, noninvasive impact hammers – to be specific Schmitt im...

Row hammer attacks exploit electrical interactions between neighboring memory cells in high-density dynamic random-access memory (DRAM) to induce memory errors. By rapidly and repeatedly accessing DRAMs with specific patterns, an adversary with limited privilege on the target machine may trigger bit flips in memory regions that he has no permission to access directly. In this paper, we explore ...