Scientific Instruments Research Papers - Academia.edu (original) (raw)
A method has been developed that uses three input tones to measure both even and odd order intermodulation distortions (IMDs) inside the pass band of resonant devices. With this technique the surface current density of both the driving... more
A method has been developed that uses three input tones to measure both even and odd order intermodulation distortions (IMDs) inside the pass band of resonant devices. With this technique the surface current density of both the driving signal and the IMD tones can be quantified. Synchronous, or same frequency, measurement of both even and odd order distortions permits quantitative comparison of the respective nonlinearity currents measured within the same time scale. As an example of this technique, a superconducting resonator is used to generate even and odd order IMDs at the same frequency, resulting in physical conclusions, which are pertinent to current research in high temperature superconductors. While varying the level of only one tone, the expected slope of the IMD current versus the driving signal current for both orders is unity, but that is only observed at high temperature when the superconductor becomes very lossy. An observed smaller slope at lower temperatures gives support to the linear-nonlinear interaction model. Also, a sharp increase in the third order IMD relative to the second order IMD near TC gives support to a substantial nonlinear Meissner effect.
This article describes a fiber-optic interrogation device based on the pulsed time-of-flight technique. The apparatus is capable of measuring time delays between wideband reflectors, such as connectors, along a fiber path with a precision... more
This article describes a fiber-optic interrogation device based on the pulsed time-of-flight technique. The apparatus is capable of measuring time delays between wideband reflectors, such as connectors, along a fiber path with a precision of about 280 fs (rms value) and a spatial resolution of about 3 ns (0.30 m) in a measurement time of 25 ms. Potential application areas include measuring integral strain and its derivatives such as cracks, deflections, and displacements, particularly in large civil engineering and composite structures. The operation and basic blocks of the measurement system are presented in detail together with measurement results obtained in laboratory and field conditions. It is shown that by using a fiber loop sensor with a reference fiber, it is possible to achieve a strain precision below 1 microstrain and a measurement frequency of 4 Hz. System performance proved adequate for the study of both static and dynamic phenomena in a bridge deck.
This paper describes the design of a very simple displacement sensor that measures the change in the position of an object by sensing the change in capacitance due to the movement of this object in the sensor fringing electric field. Two... more
This paper describes the design of a very simple displacement sensor that measures the change in the position of an object by sensing the change in capacitance due to the movement of this object in the sensor fringing electric field. Two sensor geometries with small footprints were considered and several sensor variations were built and tested. At distances of approximately 0.5 μm and 30 μm, test results demonstrated that the sensors' resolution was in the order of tens of nanometers.
A thermal property microscopy technique based on frequency domain thermoreflectance (FDTR) is presented. In FDTR, a periodically modulated laser locally heats a sample while a second probe beam monitors the surface reflectivity, which is... more
A thermal property microscopy technique based on frequency domain thermoreflectance (FDTR) is presented. In FDTR, a periodically modulated laser locally heats a sample while a second probe beam monitors the surface reflectivity, which is related to the thermal properties of the sample with an analytical model. Here, we extend FDTR into an imaging technique capable of producing micrometer-scale maps of several thermophysical properties simultaneously. Thermal phase images are recorded at multiple frequencies chosen for maximum sensitivity to thermal properties of interest according to a thermal model of the sample. The phase versus frequency curves are then fit point-by-point to obtain quantitative thermal property images of various combinations of thermal properties in multilayer samples, including the in-plane and cross-plane thermal conductivities, heat capacity, thermal interface conductance, and film thickness. An FDTR microscope based on two continuous-wave lasers is described,...
We describe an x-ray absorption method for in situ density measurement of non-crystalline materials in the diamond anvil cell using a monochromatic synchrotron x-ray microbeam. Sample thickness, which is indispensable in the absorption... more
We describe an x-ray absorption method for in situ density measurement of non-crystalline materials in the diamond anvil cell using a monochromatic synchrotron x-ray microbeam. Sample thickness, which is indispensable in the absorption method, can be determined precisely by extrapolating the thickness profile of the gasket obtained by x-ray absorption and diffraction measurements. Diamond deformation across the sample chamber becomes
Spectrophotometers are operated in numerous fields of science and industry for a variety of applications. In order to provide confidence for the measured data, analyzing the associated uncertainty is valuable. However, the uncertainty of... more
Spectrophotometers are operated in numerous fields of science and industry for a variety of applications. In order to provide confidence for the measured data, analyzing the associated uncertainty is valuable. However, the uncertainty of the measurement results is often unknown or reduced to sample-related contributions. In this paper, we describe our approach for the systematic determination of the measurement uncertainty of the commercially available two-channel spectrophotometer Agilent Cary 5000 in accordance with the Guide to the expression of uncertainty in measurements. We focus on the instrumentation-related uncertainty contributions rather than the specific application and thus outline a general procedure which can be adapted for other instruments. Moreover, we discover a systematic signal deviation due to the inertia of the measurement amplifier and develop and apply a correction procedure. Thereby we increase the usable dynamic range of the instrument by more than one ord...
An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum... more
An electrostatic cryogenic storage ring, CSR, for beams of anions and cations with up to 300 keV kinetic energy per unit charge has been designed, constructed, and put into operation. With a circumference of 35 m, the ion-beam vacuum chambers and all beam optics are in a cryostat and cooled by a closed-cycle liquid helium system. At temperatures as low as (5.5 ± 1) K inside the ring, storage time constants of several minutes up to almost an hour were observed for atomic and molecular, anion and cation beams at an energy of 60 keV. The ion-beam intensity, energy-dependent closed-orbit shifts (dispersion), and the focusing properties of the machine were studied by a system of capacitive pickups. The Schottky-noise spectrum of the stored ions revealed a broadening of the momentum distribution on a time scale of 1000 s. Photodetachment of stored anions was used in the beam lifetime measurements. The detachment rate by anion collisions with residual-gas molecules was found to be extremel...
Thickness is a governing factor in the behavior of films and coatings. To enable the high-throughput analysis of this parameter in polymer systems, we detail the design and operation of a ``flow coater'' device for fabricating... more
Thickness is a governing factor in the behavior of films and coatings. To enable the high-throughput analysis of this parameter in polymer systems, we detail the design and operation of a ``flow coater'' device for fabricating continuous libraries of polymer film thickness over tailored ranges. Focusing on the production of model polystyrene film libraries, we thoroughly outline the performance of
This paper presents a piezoelectric tube scanner with a novel electrode pattern and describes how it may be used for simultaneous sensing and actuation. The electrodes are arranged such that the tube is driven in an antisymmetrical... more
This paper presents a piezoelectric tube scanner with a novel electrode pattern and describes how it may be used for simultaneous sensing and actuation. The electrodes are arranged such that the tube is driven in an antisymmetrical manner, resulting in a collocated system ...
- by Matthias Arenz and +1
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- Engineering, Electrochemistry, FTIR spectroscopy, LabVIEW
La reconstitution des collections de la Faculté des Sciences de Rennes nous a permis de retrouver des appareils exceptionnels . C'est ainsi que nous avons « remis à jour » des copies anciennes des appareils de mesure utilisés par les... more
La reconstitution des collections de la Faculté des Sciences de Rennes nous a permis de retrouver des appareils exceptionnels . C'est ainsi que nous avons « remis à jour » des copies anciennes des appareils de mesure utilisés par les Curie pour étudier la radioactivité de certains corps. Dans cet article , nous présentons ces instruments exceptionnels que nous avons « redécouverts » : électroscope, balance à quartz, électromètre, balance apériodique, wattmètre,... Ces appareils datent de la période 1890-1905.
The reconstitution of the collections of the Faculty of Sciences of Rennes helped us find great devices. Thus we have "updated" old copies of the measuring devices used by Curie for studying radioactivity of certain bodies. In this article, we present these exceptional instruments we have "rediscovered" electroscope, quartz balance, electrometer, aperiodic balance, power meter, ... These devices date from the period 1890-1905.
Several astronomical instruments, made by many rings, have been invented and realized in Classical Antiquity to represent the celestial sphere, different models of the Universe or to observe the sky. In this paper I present a brief... more
Several astronomical instruments, made by many rings, have been invented and realized in Classical Antiquity to represent the celestial sphere, different models of the Universe or to observe the sky. In this paper I present a brief history of these objects and a classification of their different tipologies. Due to the limitation of space, I limited my description to the armillaries spheres made in Europe before the XVIIth century and I have not included other instruments with rings, like the universal equinoctial sundials. (NB The paper is in Italian)
Multichannel pipettes are used widely to accelerate research and testing in life sciences laboratories and within the biomedical industry. Commercial multichannel pipettes cost several hundred to thousand U.S. dollars and are not... more
Multichannel pipettes are used widely to accelerate research and testing in life sciences laboratories and within the biomedical industry. Commercial multichannel pipettes cost several hundred to thousand U.S. dollars and are not accessible in many areas. This study utilizes an open source and digital distributed manufacturing model to design a USD$24 4-channel 200 micro-liter pipette. The design uses widely-available interchangeable off-the-shelf parts and custom components, which can be fabricated with a low-cost fused-filament RepRap-class desktop 3D printer. The manuscript describes the design, construction, and validation of an ergonomic open-source multichannel pipette, as well as the evaluation of pipetting parameters and quality control. The open source multichannel pipette is found to be compliant with ISO 8655 standards for precision and accuracy. The device has separate syringes that operate individual tips, which prevents cross contamination of specimens because there is no direct contact of different liquids with each other and no mixing with actuating air. Each syringe is easily replaced for different experiments and the source CAD files are provided to enable others to build variants or custom configurations of the open source multichannel pipette.
Distributed digital manufacturing of free and open-source scientific hardware (FOSH) used for scientific experiments has been shown to in general reduce the costs of scientific hardware by 90–99%. In part due to these cost savings, the... more
Distributed digital manufacturing of free and open-source scientific hardware (FOSH) used for scientific experiments has been shown to in general reduce the costs of scientific hardware by 90–99%. In part due to these cost savings, the manufacturing of scientific equipment is beginning to move away from a central paradigm of purchasing proprietary equipment to one in which scientists themselves download open-source designs, fabricate components with digital manufacturing technology, and then assemble the equipment themselves. This trend introduces a need for new formal design procedures that designers can follow when targeting this scientific audience. This study provides five steps in the procedure, encompassing six design principles for the development of free and open-source hardware for scientific applications. A case study is provided for an open-source slide dryer that can be easily fabricated for under $20, which is more than 300 times less than some commercial alternatives. The bespoke design is parametric and easily adjusted for many applications. By designing using open-source principles and the proposed procedures, the outcome will be customizable, under control of the researcher, less expensive than commercial options, more maintainable, and will have many applications that benefit the user since the design documentation is open and freely accessible.