Traditional coordinate measuring systems rely on the accurate kinematics of moving a sensor to the workpiece. This paper describes an instrument using a precision rotary stage to rotate a workpiece ...with respect to a set of three laser line sensors. The accuracy of the point cloud obtained from a single rotation of the workpiece is dependent on the rotational accuracy of the stage and knowledge of the location of the line sensors with respect to the rotary axis and each other. The calibration procedure required to locate these line sensors utilizes a precision artefact placed on the rotary stage.
Variability is unavoidable in the realization of products. While design must specify ideal geometry, it shall also describe limits of variability (tolerances) that must be met in order to maintain ...proper product function. Although tolerancing is a mature field, new manufacturing processes and design methodologies are creating new avenues of research, and modelling standards must also evolve to support these processes. In addition, the study of uncertainty has produced widely-accepted methods of quantifying variability, and modern tolerancing tools should support these methods. The challenges introduced by new processes and design methodologies continue to make tolerancing research a fertile and productive area.
Spectrally resolved scattering of ultrafast K-α x-rays has provided experimental validation of the modeling of the compression and heating of shocked matter. The elastic scattering component has ...characterized the evolution and coalescence of two shocks launched by a nanosecond laser pulse into lithium hydride with an unprecedented temporal resolution of 10 picoseconds. At shock coalescence, we observed rapid heating to temperatures of 25,000 kelvin when the scattering spectra show the collective plasmon oscillations that indicate the transition to the dense metallic plasma state. The plasmon frequency determines the material compression, which is found to be a factor of 3, thereby reaching conditions in the laboratory relevant for studying the physics of planetary formation.
Estimation of the uncertainty of Coordinate Measuring Machine (CMM) measurements for real, imperfect parts is a very complex undertaking. Not only are there many contributors to the uncertainty that ...may interact in a non-linear fashion, making it difficult to mathematically determine an uncertainty estimate, but it is also difficult to predict the long-term variation of these parameters. Our work seeks to provide experimental validation of the uncertainties predicted by two different commercial software packages that purport to predict the task-specific measuring uncertainty of CMM measurement results. The validation procedure uses repeated measurements of calibrated artifacts to experimentally determine measurement uncertainties. These measurements can then be simulated in the commercial software packages. The comparison will allow the software to be tested to see if it appropriately accounts for the influences of the operator, environment, and part placement. This paper reports the results of actual part measurements and the predicted uncertainty provided by commercial simulation packages. Differences between experimental and simulated uncertainties are highlighted, and their causes examined.
Au foils were irradiated with a 100-TW, 100-fs laser at intensities greater than 10(20) W/cm2 producing proton beams with a total yield of approximately 10(11) and maximum proton energy of >9 MeV. ...Removing contamination from the back surface of Au foils with an Ar-ion sputter gun reduced the total yield of accelerated protons to less than 1% of the yield observed without removing contamination. Removing contamination from the front surface (laser-interaction side) of the target had no observable effect on the proton beam. We present a one-dimensional particle-in-cell simulation that models the experiment. Both experimental and simulation results are consistent with the back-surface acceleration mechanism described in the text.
The publication of the latest edition of ISO 1101 in 2017 is a landmark event in the development of ISO tolerancing standards. It represents an important milestone in the evolution of ISO tolerancing ...standards powered by a synergy between technological developments in tolerancing (for specification) and metrology (for verification). The external forces that caused this synergistic evolution stem from digitization of manufacturing (also variously called Smart Manufacturing, Cyber-Manufacturing, Cyber-Physical Production Systems, and Industrie 4.0). This paper provides a brief analysis of a new set of customer-facing ISO tolerancing standards which, along with their promises and challenges, will have a significant impact on digitization of manufacturing.
The power of proline: Bold amino acid substitutions in sensitive protein regions are frequently unproductive, while more subtle mutations can be sufficient to bring about dramatic changes. But ...introducing proline at the residue next to the sulfur ligand in P450BM₃ (CYP102A1) has the unexpected and desirable effect of enhancing the activity of this fatty acid hydroxylase with a broad range of non-natural substrates, as illustrated by the figure.
Navigating the Perils of Ransomware Morse, Edward A.; Ramsey, Ian
The Business Lawyer,
12/2016, Letnik:
72, Številka:
1
Journal Article, Trade Publication Article
Recenzirano
According to McAfee, " generally, there is no need to enable macros to view the contents of a document. Economic sanctions are rooted in laws that implement political policies by regulating private ...commercial actors in order to support foreign policy and national security goals.18 OFAC maintains a searchable database of designated parties and relevant sanction restrictions.19 Thus, payments made to designated parties or countries covered by sanctions are clearly illegal, potentially resulting in civil or criminal penalties not only for those making the payments, but also for those facilitating them.20 Although banks are accustomed to consulting the OFAC database when making payment abroad to a designated payee, a firm making a bitcoin payment via e-mail will likely not have the name or location of the designated payee. ...the sanctions regime is unlikely to affect a ransom payment, except in cases when the criminal self-identifies in a manner triggering the sanctions regime.
The complexity of highly active antiretroviral therapy (HAART), with multiple medications, formulations, and dosing intervals, makes adherence challenging. Little is known about the adherence of ...children to HAART. The objective of this study was to identify correlates of adherence to HAART and the relationship between adherence and study outcomes in a pediatric clinical trial.
Pediatric AIDS Clinical Trials Group 377 is a phase I/II randomized trial of 4 HAART regimens in antiretroviral-experienced, clinically stable children aged 4 months to 17 years. The 4 treatment arms include various 3- or 4-drug combinations of d4T, 3TC, nevirapine, ritonavir, and nelfinavir. After informed consent was obtained, 193 children were enrolled between December 1997 and September 1998. Questionnaires were developed to collect subject- or caregiver-reported adherence to study medications and to identify problems associated with medication administration. Every 3 months, the number of doses of each medication missed during the 3 days preceding the study visit was recorded. Full adherence (FA) and non-full adherence were defined as missing no doses and missing at least 1 dose, respectively.
Adherence data from study week 48 or the most recent study visit were available for 125 children (week 48 for 109 children). Overall, 70% of children reported FA and 30% reported non-full adherence. Adherence did not differ by treatment arm, age, or the child's knowledge of his or her human immunodeficiency virus infection status. There was a suggestion that adherence was less for white than nonwhite children (40% vs 73% FA) and did not differ between black and Hispanic children. Rates of FA were 82% for d4T, 79% for 3TC, 83% for nevirapine, 84% for ritonavir, and 68% for nelfinavir. Despite the similar rates of FA, difficulties with taking specific medications were reported most frequently for ritonavir and nelfinavir. These included poor taste, patient refusal, and scheduling problems. Adherence was associated with the virologic response: FA was seen in 92% of children with > or =2 log10 drop in viral load and in 64% with <2 log10 drop in viral load.
In children, reported adherence predicts the virologic response to HAART therapy and is a useful measure of adherence. Interventions and regimens to increase adherence to HAART should result in an improved outcome.
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