Laser frequency noise is a significant noise source which couples into the main science measurement of the Laser Interferometer Space Antenna via the mismatch between the interferometer arm lengths. In this paper we discuss the application of an unequal pathlength heterodyne Mach–Zehnder interferometer to measure and actively stablize the master laser frequency as used in LISA Pathfinder. In co...

creep phenomenon in rock engineering plays a key role in development of underground spaces as they must be stable enough for a long period of time. current research involved designing and manufacturing of a new creep testing machine. the equipment is capable to perform simultaneous light-duty creep tests on more than one cylindrical rock samples at a very low cost.to evaluate the equipment’s pe...

this study on the design of pid controllers for flexible single-arm robot system optimizationpso method is focused so that the coefficients of the pid controller are reduced. in this study,pid controller and pso algorithm have been described and then by using matlab, pidcontrol was simulated. then by pso algorithm, attempts to reduce the pid coefficients are givenby simulation. finally pid coef...

today, one of the new technologies in the modern era is vehicular ad-hoc network which has takenenormous attention in the recent years. because of rapid topology changing and frequent disconnectionmakes it difficult to design an efficient routing protocol for routing data between vehicles, called v2v orvehicle to vehicle communication and vehicle to roadside infrastructure, called v2i. designin...

objectives this study aimed to examine the relationship between patients’ anthropometric characteristics and depth of spinal needle insertion to the subarachnoid cavity. patients and methods 385 patients with asa class i – ii, aged 18 - 65 years and undergoing elective surgery of the lower abdomen and extremities under spinal anesthesia, were selected for this cross-sectional study. the patient...

background: here we describe a new case of partial distal 10q trisomy in a 6-year-old iranian girl from healthy parents with mental, growth, and psychomotor retardations. methods: additional clinical features include dysmorphic craniofacial features, microcephaly, bilateral hydronephrosis without heart problems, small and rotated low-set ears, bow-shaped mouth, abnormal teeth, short neck, and a...

The ratio-type estimators have been introduced for estimating the mean and total population, but in recent years based on the ratio methods several estimators for population variance have been proposed. In this paper two families of estimators have been suggested and their approximation mean square error (MSE) have been developed. In addition, the efficiency of these variance estimators are com...