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The article presents information on issues that relate to the articles that appeared in the August 12, 2008 issue of "AIP Conference Proceedings."

Phased array ultrasonic reconstruction techniques are often presented as a prospect for better and enhanced diagnosis. However to date few applications of these techniques can be found in the industry, partly because of questions on sizing but also because they often require heavy acquisitions. A way forward is then to propose techniques requiring less intensive data acquisition to make them broadly affordable in practice. Several approaches ranging from full matrix capture to paintbrush acquisitions are presented in this paper in combination with associated reconstruction processing like the Total Focusing Method (TFM) and the Time Domain Topological Energy (TDTE) techniques. Emphasis is given to their relative relevancies and practical applicability on typical configurations of interest for industries. The paper also presents recent efforts made on the acceleration of processing computation times, in particular through the use of GPU architectures. [ABSTRACT FROM AUTHOR]

Results of Couette flow investigation are given for the free-molecule flow regime as well as or the transitional one. The numerical solution of Boltzmann equation by the direct Monte Carlo simulation method is used in our paper for investigating the Couette flow in a wide range of values of plate temperatures ratio, Knudsen number and the upper plate velocity. The dependences of the energy flux transferred towards the lower plate, of the shear stress, and of the flux of normal momentum on the Knudsen number are considered. It is found that for any Mach number there exists the interval of plate temperatures ratios such that the energy flux towards the plate changes the sign if the Knudsen number increases, previously reaching a local extremum. It is demonstrated as well that the effect of nonmonotonicity at high Mach number is observed not only for the shear stress and the energy flux but for the normal momentum flux as well. We also found the cases where the energy flux varies monotonically or even has a deep negative minimum, but the shear stress has a maximum. [ABSTRACT FROM AUTHOR]

A new mathematic model of location optimization for viscoelastic dampers is established through energy analysis based on force analogy method. Three working conditions (three lower limits of the new location index) as well as four ground motions are considered in this study, using MATLAB and SAP2000 in programming and verifying. This paper deals with the optimal placement of viscoelastic dampers and step-by-step time history analyses are carried out. Numerical analysis is illustrated to verify the effectiveness and feasibility of the new mathematic model for structural control. In addition, not only the optimal placement method using force analogy method can confirm dampers' locations all at once and be accurate to each span, but also it is without circular calculating. At last, a few helpful conclusions on viscoelastic dampers' optimal placement are made. [ABSTRACT FROM AUTHOR]

Low thrust engines with high specific impulse and long lifetime that allow for precise distance control in satellite formation flight and compensation of small disturbing forces become increasingly important in missions for geodetic purposes or astronomic science. Currently available microthrusters cannot yet meet these demands. Laser ablative micropropulsion is a relatively new concept that has already proven its potential for providing very small impulse bits and high specific impulses. Additionally, by using electro-optic beam control even the most stringent conditions like "no moving parts" could be met. An overview of the experimental facilities for characterization of the ablation process and future plans for the experimental setups are presented. In a first step, laser ablation of metal targets in a vacuum vessel using short pulse solid state laser sources is investigated. In this paper we present first results on Faraday cup and profilometry measurements and discuss their impact on further investigations of plume characteristics. Future experimental goals as well as DLR's research strategy for the development of precise and reliable laser ablation microthrusters are addressed. [ABSTRACT FROM AUTHOR]

We introduce the use of commutators in Classical Mechanics and explore some of the consequences of having two dynamical variables related by a constant commutator (conjugate variables). In this paper, we find complementary motions in phase-space for pairs of conjugate variables. If a dynamical quantity is the Hamiltonian of a mechanical system, the complementary motion takes place on the energy direction. Our results are of help in the understanding of a quantum conceptual problem: the Pauli theorem. [ABSTRACT FROM AUTHOR]

This paper demonstrates the use of an intelligent shimming system to compensate for changes in process output due to tool wear. A new tool concept with integrated hydraulic cavities used as actuators in feedback control system is presented. By prescribing a hydraulic pressure in the individual cavities the blank-holder force distribution can be controlled during the punch stroke. By means of a sequence of numerical simulations abrasive wear is imposed to the deep drawing of a rectangular cup. The abrasive wear is modelled by changing the tool surface geometry using an algorithm based on the sliding energy density. As the tool surfaces are changed the material draw-in is significantly altered when using conventional open-loop control of the blank-holder force. A feed-back controller is presented which is capable of reducing the draw-in difference to a certain degree. Further a learning algorithm is introduced to the system, which is able to improve the response of the feed-back system significantly. [ABSTRACT FROM AUTHOR]

In this paper, an electroless etching using a mixed solution of hydrofluoric acid and silver nitrite on (100) and (111) silicon substrates was conducted which led to the formation of well-aligned nanowire arrays. In (100) silicon substrate, the density of nanowires networks are much wider apart than that in (111) Si substrate. In addition, the length of the nanowires in (100) Si substrate is almost two times longer than that on (111) Si substrate. It is possibly due to the fact of the orientation where the atoms are much closer packed together in (111), indicating that the process may require more energy to etch deeper and wider. It is also observed the length of SiNWs has increased when the etching temperature increases from 25° C to 50° C. Similar behavior is also noted as the hydrofluoric acid molar concentration increases from 1M to 5 M. [ABSTRACT FROM AUTHOR]

In the present paper we consider the linear theory of thermoelasticity of type III for anisotropic and inhomogeneous bodies as developed by Green and Naghdi (1992, 1995). We consider a right prismatic cylinder of either finite or semi-infinite length and with a plane base, made of an anisotropic and inhomogeneous thermoelastic material. The cylinder is subject to zero body supplies and prescribed tractions and prescribed heat flux on its base and the lateral boundary is heat flux free and traction free. We establish results describing properties of spatial behaviour for the corresponding transient solutions. In fact, for a finite cylinder, we establish some spatial decay estimates for a certain energetic measure of the solution describing the spatial decay of the end effects with respect to the distance to the loaded and heated base, provided the density mass is strictly positive, the specific internal energy is assumed to be a positive definite quadratic form and the heat conductivity tensor is positive definite. In the limiting case when a semi-infinite cylinder is considered we are able to establish an alternative of Phragmén-Lindelöf type. We outline that in the case of a thermoelastic material for which the axial component q3 of the heat flux is independent of the time derivative of the thermal displacement gradient, we are able to establish a theorem of influence domain. When the lateral boundary surface is maintained at zero thermal displacement, we obtain spatial estimates by means of a comparison principle involving solutions of the classical one-dimensional heat equation. [ABSTRACT FROM AUTHOR]

Photoresist outgassing can significantly compromise accurate dosimetry of high energy implants. High energy implant even at a modest beam current produces high beam powers which create significantly worse outgassing than low and medium energy implants and the outgassing continues throughout the implant due to the low dose in typical high energy implant recipes. In the previous generation of high energy implanters, dose correction by monitoring of process chamber pressure during photoresist outgassing has been used. However, as applications diversify and requirements change, the need arises for a more versatile photoresist correction system to match the versatility of a single wafer high energy ion implanter. We have successfully developed a new dosimetry system for the Optima XE single wafer high energy ion implanter which does not require any form of compensation due to the implant conditions. This paper describes the principles and performance of this new dose system. [ABSTRACT FROM AUTHOR]

Modeling of collision processes of colliding bodies with different properties is of particular theoretical and practical interest e.g. for modeling of plastic deformation processes. Best results regarding the parameters of the collision processes (forces, stress, strain, duration of contact, etc.) are obtained using the finite elements method (FEM). This paper presents the results of FEM modeling of the collision process after a free fall of a sphere on an elastic-plastic plate of specific dimensions under the additional application of an external force. Two cases are described: the application of an external force during the time of contact of the colliding bodies, and without application of an external force. Correlations were obtained for the change of the strength of the impact, the stress and strain as function of time for the sphere and the plate. The strain of the plate were defined for various values of the external force. These results allow us to define the conditions, necessary to perform the so called 'Combined Impact' leading to significant change of the deformation processes conditions. [ABSTRACT FROM AUTHOR]

In this paper we present the design of the high-gradient, high-energy-gain IFEL accelerator proposed for construction at the ATF beamline in BNL. We plan to accelerate the ATF electron beam from 50 MeV to 120 MeV using a 60 cm long tapered permanent magnet helical undulator designed at UCLA and the existing ATF 0.5 TW CO2 laser system. The experiment will obtain a record 120 MV/m gradient and >70 MeV energy gain and will be an important step in the development of compact IFEL accelerators for the mid-high energy range (up to 1-2 GeV). [ABSTRACT FROM AUTHOR]

The question of what constitutes optimal distance running biomechanics has not been settled. This paper investigates the possibility that optimal distance running biomechaincs-good 'form'-consist of minimizing fluctuations in the runner's angular momentum about the runner's center of mass during stance phase. A method is proposed for estimating these fluctuations based solely on two-dimensional force plate data. [ABSTRACT FROM AUTHOR]

In physics education research, the main goal is to improve physics teaching so that most students understand physics conceptually and be able to apply concepts in solving problems. Therefore many multiple-choice instruments were developed to probe students’ conceptual understanding in various topics. Two techniques including model analysis and item response curves were used to analyze students’ responses from Force and Motion Conceptual Evaluation (FMCE). For this study FMCE data from more than 1000 students at Chiang Mai University were collected over the past three years. With model analysis, we can obtain students’ alternative knowledge and the probabilities for students to use such knowledge in a range of equivalent contexts. The model analysis consists of two algorithms—concentration factor and model estimation. This paper only presents results from using the model estimation algorithm to obtain a model plot. The plot helps to identify a class model state whether it is in the misconception region or not. Item response curve (IRC) derived from item response theory is a plot between percentages of students selecting a particular choice versus their total score. Pros and cons of both techniques are compared and discussed. [ABSTRACT FROM AUTHOR]

The Maia detector system is engineered for energy dispersive x-ray fluorescence spectroscopy and elemental imaging at photon rates exceeding 107/s, integrated scanning of samples for pixel transit times as small as 50μs and high definition images of 108 pixels and real-time processing of detected events for spectral deconvolution and online display of pure elemental images. The system developed by CSIRO and BNL combines a planar silicon 384 detector array, application-specific integrated circuits for pulse shaping and peak detection and sampling and optical data transmission to an FPGA-based pipelined, parallel processor. This paper describes the system and the underpinning engineering solutions. [ABSTRACT FROM AUTHOR]

In this paper, the mechanism of detonation to quasi-detonation transition was discussed, a new physical model to simulate quasi-detonation was proposed, and one-dimensional theoretical and numerical simulation was conducted. This study firstly demonstrates that the quasi-detonation is of thermal choking. If the conditions of thermal choking are created by some disturbances, the supersonic flow is then unable to accept additional thermal energy, and the CJ detonation becomes the unstable quasi-detonation precipitately. The kinetic energy loss caused by this transition process is firstly considered in this new physical model. The numerical results are in good agreement with previous experimental observations qualitatively, which demonstrates that the quasi-detonation model is physically correct and the study are fundamentally important for detonation and supersonic combustion research. [ABSTRACT FROM AUTHOR]

HTS power cable systems of to several hundred meters in length are presently being developed and evaluated for practical use in real power grids. Since 2006, a cooling system for the 3-phase, 100-m HTS power cable with 22.9 kV/1.25 kA has been installed and tested at the KEPCO’s Gochang power-testing center. Performance reliability through several demonstration tests of over 9,000 hours was demonstrated. This paper mainly describes the cooling performance test results of the HTS power cable system obtained during the long-term performance tests. [ABSTRACT FROM AUTHOR]

The thermal control system for a Venus Lander is critical to mission success and the harsh operating environment presents significant thermal design and implementation challenges. A successful thermal architecture draws heavily from previous missions to the Venus surface such as Pioneer Venus and the Soviet Venera Landers. Future Venus missions will require more advanced thermal control strategies to allow greater science return than previous missions and will need to operate for more than one or two hours as previous missions have done. This paper describes a Venus Lander thermal architecture including the technology development of a phase change material system for absorbing the heat generated within the Lander itself and an insulation system for resisting the heat penetrating the Lander from the Venus environment. The phase change energy storage system uses lithium nitrate that can absorb twice the amount of energy per unit mass in comparison to paraffin based systems. The insulation system uses a porous silica material capable of handling a high temperature and high pressure gas environment while maintaining low thermal conductivity. [ABSTRACT FROM AUTHOR]

This paper proposes an application of Distinct Element Method (DEM) to the simulation of fragment dispersion of concrete subjected to an impact or impulsive load. First, the high speed loading experiment to the standard shape concrete specimens are carried out. The fragment characteristics, i.e., shape, mass, and velocity are measured. Secondly, in order to develop the fragment simulation method, the experimental results are simulated by using 3-D DEM with some modifications. In this analysis, elastic theory in compressive, tension-softening model in tension, and Mohr-Coulomb yield criterion are employed. [ABSTRACT FROM AUTHOR]

Inverse simulations of musculoskeletal models computes the internal forces such as muscle and joint reaction forces, which are hard to measure, using the more easily measured motion and external forces as input data. Because of the difficulties of measuring muscle forces and joint reactions, simulations are hard to validate. One way of reducing errors for the simulations is to ensure that the mathematical problem is well-posed. This paper presents a study of regularity aspects for an inverse simulation method, often called forward dynamics or dynamical optimization, that takes into account both measurement errors and muscle dynamics. Regularity is examined for a test problem around the optimum using the approximated quadratic problem. The results shows improved rank by including a regularization term in the objective that handles the mechanical over-determinancy. Using the 3-element Hill muscle model the chosen regularization term is the norm of the activation. To make the problem full-rank only the excitation bounds should be included in the constraints. However, this results in small negative values of the activation which indicates that muscles are pushing and not pulling, which is unrealistic but the error maybe small enough to be accepted for specific applications. These results are a start to ensure better results of inverse musculoskeletal simulations from a numerical point of view. [ABSTRACT FROM AUTHOR]

This paper is a very brief review of the method for analyzing the space and time dependent exergy and irreversibility fields in processes. It presents the basic equations, the method for their use, and three examples from the work of the author and his former graduate students: flow desiccation, combustion of oil droplets, and combustion of pulverized coal. Conclusions from this Second Law analysis are used to attempt process improvement suggestions. [ABSTRACT FROM AUTHOR]

The second part of a study concerning innovative intervention techniques for seismic protection of existing buildings is presented in this paper. The case of an existing framed r.c. structure, not designed for horizontal forces and extremely vulnerable to seismic action, is analyzed both in terms of maximum response reduction and energy dissipation. The proposed intervention approach, based on steel braces linked to the existing structure by passive or smart devices comes out appropriate and effective in the case of this type of buildings. The adopted control strategy produces a significant reducing effect on the elastic strain energy transmitted by the external perturbation to the structure, which is itself a fundamental safeguard aspect. The results prove the significantly improved capability of the system to dissipate input energy without structural damage, regardless of the specific seismic input. [ABSTRACT FROM AUTHOR]

The subject of the paper is a problem of designing control algorithms for mechanical systems with uncertainty. We consider a generic Lagrangian mechanical system under the assumption that its mass-inertia parameters are not known exactly and that the system is subjected to unknown bounded disturbances. We assume also that the disturbances are smaller than the control forces which in turn do not exceed the force of gravity. A bounded control is proposed which, under certain conditions, steers the system from an arbitrary initial state to a prescribed terminal state in finite time. To this end, first, for some reference dynamical system close to the original one we design a trajectory connecting the initial and the terminal states. Then, using the trajectory tracking technique we steer the system under consideration to the prescribed terminal state. The proposed approach is illustrated by the results of the computer simulation of steering a plain two-link pendulum. [ABSTRACT FROM AUTHOR]

Construction carbon steels represent an important steel class due to the large quantity in which it is produced. Generally, these steels are delivered in as-rolled or normalized condition heaving a ferrite-pearlite microstructure. For a given chemical composition, the mechanical characteristics of this microstructure are largely influenced by the grain size. Rolling is the deformation process which is most widely used for grain size refinement. Situated in the intermediate temperature range, warm-rolling presents certain advantages as compared to classical hot- or cold-working processes. The paper presents a study on the microstructure and mechanical properties of Ck15 carbon steel samples warm-rolled. After deformation, the microstructure was investigated by light microscopy. Hardness measurements were made on the section parallel to the rolling direction. The mechanical properties of the steel after warm-rolling were assessed by tensile and impact tests. Additional information concerning the fracture behavior of warm-rolled samples was obtained by examining the fracture surface by scanning electron microscopy. The microstructure of the steel proved to have good mechanical properties. By considering the technologic and energy aspects, the paper shows that warm-rolling can lead to the improvement of mechanical properties of construction carbon steels. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

The problem of dark matter in the Universe is one of the most important issues of modern cosmology. A lot of effort has been put in constraining different models of dark energy with SNIa data, CMBR, lensing or angular size statistics each of them having their own limitations and systematics. Therefore every complementary cosmological test has its value. Future generation of interferometric gravitational wave detectors is hoped to provide accurate measurements of the final stages of binary inspirals. The sources probed by such experiments are of extragalactic origin and the observed chirp mass distribution carries information about their redshifts. Moreover the luminosity distance is directly observable is such experiments. This creates the possibility to establish a new kind of cosmological tests, supplementary to more standard ones. The paper highlights the utility of gravity wave experiments for testing dark energy in the Universe. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper will review potential power system concepts for the development of the lunar outpost including power generation, energy storage and power management and distribution (PMAD). In particular, the requirements of the initial robotic missions will be discussed and the technologies considered will include cryogenics and regenerative fuel cells (RFC), AC and DC transmission line technology, high voltage and low voltage power transmission, conductor materials of construction and power beaming concepts for transmitting power to difficult to access locations such as at the bottom of craters. Operating conditions, component characteristics, reliability, maintainability, constructability, system safety, technology gaps / risk and adaptability for future lunar missions will be discussed for the technologies considered. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The goal of this paper is to review, discuss and evaluate the efficiency of different primarily experimental approaches applied to the problem of gas-surface interaction in addition to presenting some results obtained by the use of these approaches. Special attention is paid to the influence of surface structure and chemical composition on energy and momentum accommodation. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The phenomenological consideration on the energetics of molecular motor that are working at non-equilibrium conditions, is presented in this paper. First, a phenomenological equation of motion for a motor molecule is suggested, in which the physical properties of the motor are incorporated. Based on this equation of motion, the energetics of the system were considered. It is found that the energy fluxes can be expressed in terms of several mechanical observables, so that we can directly calculate the energetic efficiency of the motor experimentally. The present framework can adequately explain the recent experimental data on the energetic efficiency of kinesin. In order to gain further insight, we examined the theory by employing a well-known ratchet model, which demonstrated that the present framework is consistent with an already known framework of energetics, referred to as stochastic energetics, provided that the nonlinearity of the system is not so high. The present framework provides an easy procedure to estimate the energy fluxes on a molecular motor, with mechanical experiments at a single-molecule level. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The paper presents the numerical results obtained with the use of the ANSYS FLUENT commercial code for analysing the flow structure around two rectangular inline surface-mounted bluff bodies immersed in a boundary layer. The effects of the inflow boundary layer for the accuracy of the numerical modelling of the flow field around a simple system of objects are described. The analysis was performed for two concepts. In the former case, the inlet velocity profile was defined using the power law, whereas the kinetic and dissipation energy was defined from the equations according to Richards and Hoxey [1]. In the latter case, the inlet conditions were calculated for the flow over the rough area composed of the rectangular components. [ABSTRACT FROM AUTHOR]