In the last 30 days

• Open/close Virgo calibration and reconstruction of the gravitationnal wave strain during VSR1

  T Accadia et al 2010 J. Phys.: Conf. Ser. 228 012015 Tag this article

  Article References Full text PDF (958 KB)

  Virgo is a kilometer-length interferometer for gravitationnal waves detection located near Pisa. Its first science run, VSR1, occured from May to October 2007. The aims of the calibration are to measure the detector sensitivity and to reconstruct the time series of the gravitationnal wave strain h( t).

  The absolute length calibration is based on an original non-linear reconstruction of the differential arm length variations in free swinging Michelson configurations. It uses the laser wavelength as length standard. This method is used to calibrate the frequency dependent response of the Virgo mirror actuators and derive the detector in-loop response and sensitivity within ~ 5%.

  The principle of the strain reconstruction is highlighted and the h( t) systematic errors are estimated. A photon calibrator is used to check the sign of h( t). The reconstructed h( t) during VSR1 is valid from 10 Hz up to 10 kHz with systematic errors estimated to 6% in amplitude. The phase error is estimated to be 70 mrad below 1.9 kHz and 6 μs above.

• Open/close Magnetorheological effect of magneto-active elastomers containing large particles

  G Stepanov et al 2009 J. Phys.: Conf. Ser. 149 012098 Tag this article

  Article References Full text PDF (12.28 MB)

  The magnetorheological effect of elastomer composites containing a mixture of large (50-80 μm) and small (3-5 μm) particles has been experimentally examined. The data shows that elasticity in the range of small deformations (1%) for a magnetic field strength of 290 mT increased by two order of magnitude. This effect can be explained with the presence of the large particles in the structure of the composite assisting the aggregation effect. Due to the strong increase of the interparticle interaction compared with the restoring elastic forces, the presence of the large particles leads to the observed steep increase of Young's modulus.

• Open/close Polymer chemistry and hydrogel systems

  E H Schacht 2004 J. Phys.: Conf. Ser. 3 22 Tag this article

  Article References Full text PDF (188 KB)

  Hydrogels are an interesting class of materials that can be prepared by a variety of methods. The properties of these materials depend on their building blocks and the preparation procedures and can be largely varied.

  Among the various classes of hydrogels, are the gels based of physically structuring biopolymers, like gelatine. By chemically modifying these biopolymers, hydrogels with a dual crosslinkage (physical and chemical) can be prepared.

  Hydrogels serve a broad range of applications, including biomaterials, matrices for drug delivery and scaffolds for tissue engineering.

• Open/close The mysterious disappearance of Ettore Majorana

  Barry R Holstein 2009 J. Phys.: Conf. Ser. 173 012019 Tag this article

  Article References Full text PDF (386 KB)

  We review the short but interesting life of Ettore Majorana.

• Open/close Automotive sensors: past, present and future

  S J Prosser 2007 J. Phys.: Conf. Ser. 76 012001 Tag this article

  Article References Full text PDF (594 KB)

  This paper will provide a review of past, present and future automotive sensors. Today's vehicles have become highly complex sophisticated electronic control systems and the majority of innovations have been solely achieved through electronics and the use of advanced sensors. A range of technologies have been used over the past twenty years including silicon microengineering, thick film, capacitive, variable reluctance, optical and radar. The automotive sensor market continues to grow with respect to vehicle production level in recognition of the transition to electronically controlled electrically actuated systems. The environment for these sensors continues to be increasingly challenging with respect to robustness, reliability, quality and cost.

• Open/close The Design of Wireless Sensor Network System Based on ZigBee Technology for Greenhouse

  Y W Zhu et al 2006 J. Phys.: Conf. Ser. 48 1195 Tag this article

  Article References Full text PDF (94 KB)

  Wireless sensor network is a new research field. It can be used in some special situation for signal collection, processing and transmitting. Zigbee is a new Wireless sensor network technology characteristic of less distance and low speed. It is a new wireless network protocol stack of IEEE 802.15.4. Lately traditional system to collects parameters for Greenhouse is widely used in agriculture. The traditional system adopts wired way wiring, which makes the system complex and expensive. Generally modern Greenhouse has hundreds of square meters and they may plant variety of plants depending on different seasons. So we need to adjust the sensors which collect parameters for Greenhouse to a better place to work more efficient. Adopting wireless way wiring is convenient and economical. This paper developed a wireless sensor network system based on ZigBee technology for greenhouse. It offers flexibility and mobility to save cost and energy spent on wiring. The framework hardware and software structure, related programming are also discussed in this paper. Comparing the system which uses ZigBee technology with traditional wired network system for greenhouse, it has advantage of low cost..low power and wider coverage. Additionally it complies with IEEE802.15.4 protocol, which makes it convenient to communicate with other products that comply with the protocol too.

• Open/close Biomechanics of front and back squat exercises

  A A Braidot et al 2007 J. Phys.: Conf. Ser. 90 012009 Tag this article

  Article References Full text PDF (654 KB)

  Squat constitutes one of the most popular exercises to strengthen the muscles of the lower limbs. It is considered one of the most widely spread exercises for muscle sport training and is part of the competition movements comprised within olympic weight-lifting. In physical rehabilitation, squats are used for muscular recovery after different injuries of the lower limbs, especially the knee. In previous anterior cruciate ligament injuries, the mini-squats are generally used, in a knee flexion motion range from 0° to 50° because in this range the shear forces, the tibiofemoral and patellofemoral compression forces decrease related to greater flexion angles. The aim of this work is to make a comparative bidimensional study of the kinematic and dynamic variables of the excecution of the parallel squat exercise with the front and back bar. It is observed in the knee a better development of energy with the front bar, allowing a better muscular exercise with the same load. The mean power absorbed by the hip with the back bar is considerably greater, associated to the speed of the gesture.

• Open/close Review of noise in neonatal intensive care units – regional analysis

  A Alvarez Abril et al 2007 J. Phys.: Conf. Ser. 90 012038 Tag this article

  Article References Full text PDF (419 KB)

  This work is about the problem of noise in neonatal incubators and in the environment in the neonatal intensive care units. Its main objective is to analyse the impact of noise in hospitals of Mendoza and La Rioja.

  Methodology: The measures were taken in different moments in front of higher or lower severity level in the working environment. It is shown that noise produces severe damages and changes in the behaviour and the psychological status of the new born babies.

  Results: The noise recorded inside the incubators and the neonatal intensive care units together have many components but the noise of motors, opening and closing of access gates have been considered the most important ones. Values above 60 db and and up to 120 db in some cases were recorded, so the need to train the health staff in order to manage the new born babies, the equipment and the instruments associated with them very carefully is revealed.

• Open/close Wind turbine blade tip comparison using CFD

  E Ferrer and X Munduate 2007 J. Phys.: Conf. Ser. 75 012005 Tag this article

  Article References Full text PDF (3.05 MB)

  The effect of wind turbine blade tip geometry is numerically analysed using Computational Fluid Dynamics (CFD). Three different rotating blade tips are compared for attached flow conditions and the flow physics around the geometries are analysed. To this end, the pressure coefficient (Cp) is defined based on the stagnation pressure rather than on the inflow dynamic pressure. The tip geometry locally modifies the angles of attack (AOA) and the inflow dynamic pressure at each of the studied sections. However not all 3D effects could be reduced to a change of these two variables. An increase in loadings (particularly the normal force) towards the tip seem to be associated to a spanwise flow component present for the swept-back analysed tip. Integrated loads are ranked to asses wind turbine tip overall performance. It results from the comparison that a better tip shape that produced better torque to thrust ratios in both forces and moments is a geometry that has the end tip at the pitch axis. The work here presented shows that CFD may prove to be useful to complement 2D based methods on the design of new wind turbine blade tips.

• Open/close Proteins as data storage devices: insights from computer models

  Miguel Ortiz-Lombardía and Chandra S Verma 2006 J. Phys.: Conf. Ser. 34 7 Tag this article

  Article References Full text PDF (427 KB)

  The ability to use charge transporting proteins such as bacteriorhodopsin in the building of data storage and transmission devices for use in computer technology is explored. Designs of mutants that lead to proteins that are more stable thermally and more efficient at data processing requires knowledge of the elctrostatics/dynamics of the molecules. We find that both the motions and the electrostatics are strongly effected when the influence of neighbouring molecules in the assembly are included, underscoring the importance of inclusion of the assemblies explicitly in computer models.