Design Of Sample Holder Research Articles

Transient-Absorption Spectroscopy of Cis–Trans Isomerization of N,N-Dimethyl-4,4′-azodianiline with 3D-Printed Temperature-Controlled Sample Holder

The laboratory unit demonstrates a project-based approach to teaching physical chemistry laboratory where upper-division undergraduates carry out a transient-absorption experiment investigating the kinetics of cis–trans isomerization of N,N-dimethyl-4,4′-azodianiline. Students participate in modification of a standard flash-photolysis spectrometer by adding a temperature-controlled sample holder. The sample holder design is open-source and can be reproduced with the 3D-printing technology. Students build the experimental setup, perform the transient spectroscopy experiment, and analyze the obtained kinetics data to estimate the activation energy, enthalpy, entropy, and Gibbs free energy of cis–trans isomerization of N,N-dimethyl-4,4′-azodianiline.

Evaluation of Cooling Conditions for a High Heat Flux Testing Facility Based on Plasma-Arc Lamps

The new Irradiated Material Target Station (IMTS) facility for fusion materials at Oak Ridge National Laboratory (ORNL) uses an infrared plasma-arc lamp (PAL) to deliver incident heat fluxes as high as 27 MW/m2. The facility is being used to test neutron irradiated plasma-facing component materials as part of the joint US-Japan PHENIX program. The irradiated samples are to be mounted on molybdenum sample holders attached to a water-cooled copper rod. Depending on the size and geometry of samples, several sample holders and copper rod configurations have been fabricated and tested.As a part of the effort to design sample holders compatible with the high heat flux (HHF) testing to be conducted at the IMTS facility, numerical simulations have been performed for two different water-cooled sample holder designs using the ANSYS™ FLUENT® 14.0 commercial computational fluid dynamics (CFD) software package. The primary objective of this work is to evaluate the cooling capability of different sample holder designs, i.e. to estimate their maximum allowable incident heat flux values.2D axisymmetric numerical simulations are performed using the realizable k-ε turbulence model and the RPI nucleate boiling model within ANSYS™ FLUENT® 14.0. The results of the numerical model were compared against the experimental data for two sample holder designs tested in the IMTS facility. The model has been used to parametrically evaluate the effect of various operational parameters on the predicted temperature distributions. The results were used to identify the limiting parameter for safe operation of the two sample holders and the associated peak heat flux limits. The results of this investigation will help guide the development of new sample holder designs.

Design and Manufacturing of a Conduction-Cooled Sample Holder for a Superconducting Property Measurement System

We had developed four years ago a superconducting property measurement system (SPMS) that can be used to acquire electrical and thermal properties of high-temperature superconductor (HTS) tape samples. The SPMS was composed of the sample holder for mounting an HTS tape and 3 T HTS magnet, both cooled individually by conduction using a cryocooler. The maximum dimension of the HTS tape sample that could be loaded on the sample holder was 15 mm in width and 250 mm in length. The conduction-cooled sample holder was again fabricated to increase the maximum test current up to 800 A. Maximum transport current was 763 A in magnetic field intensity 3 T. The measuring temperature range was 15-50 K.

Development of an Integrated Thermocouple for the Accurate Sample Temperature Measurement During High Temperature Environmental Scanning Electron Microscopy (HT-ESEM) Experiments.

We have developed two integrated thermocouple (TC) crucible systems that allow precise measurement of sample temperature when using a furnace associated with an environmental scanning electron microscope (ESEM). Sample temperatures measured with these systems are precise (±5°C) and reliable. The TC crucible systems allow working with solids and liquids (silicate melts or ionic liquids), independent of the gas composition and pressure. These sample holder designs will allow end users to perform experiments at high temperature in the ESEM chamber with high precision control of the sample temperature.

Enhanced positioning precision and in situ macroscopic contacts for shadow-evaporated nanostructures

The authors present the design of a modular sample holder that offers the possibility of in situ fabrication of metallic nanostructures under ultrahigh vacuum. One of the crucial points is to bridge the gap between the macroscopic leads and the nanostructure itself. This problem is solved by using a set of two different masks. For a precise alignment of the two masks, a magnetic tripod connection system has been developed. With this new system, an alignment precision of 26 μm is obtained. As a result of the fabrication in ultrahigh vacuum, the nanostructures will be accessible to scanning probe techniques without surface contamination. First results show that electrical measurements are indeed possible.

Electrical conductivity measurements on disk-shaped samples.

We have developed a sample holder design that allows for electrical conductivity measurements on a disk-shaped sample. The sample holder design is based on and compatible with popular measurement systems that are currently restricted to bar-shaped samples. The geometrical correction factors which account for the adjusted measurement configuration were calculated using finite element modeling for a broad range of sample and measurement geometries. We also show that the modeling results can be approximated by a simple analytical fit function with excellent accuracy. The proposed sample holder design is compatible with a concurrent measurement of the Seebeck coefficient. The chosen sample geometry is furthermore compatible with a thermal conductivity measurement using a laser flash apparatus. A complete thermoelectric characterization without cutting the sample is thus possible.

Miniaturization in voltammetry: Ultratrace element analysis and speciation with twenty-fold sample size reduction

Voltammetric techniques have emerged as powerful methods for the determination and speciation of trace and ultratrace elements without any preconcentration in several research fields. Nevertheless, large sample volumes are typically required (10mL), which strongly limits their application and/or the precision of the results. In this work, we report a 20-fold reduction in sample size for trace and ultratrace elemental determination and speciation by conventional voltammetric instrumentation, introducing the lowest amount of sample (0.5mL) in which ultratrace detection has been performed up to now. This goal was achieved by a careful design of a new sample holder. Reliable, validated results were obtained for the determination of trace/ultratrace elements in rainwater (Cd, Co, Cu, Ni, Pb) and seawater (Cu). Moreover, copper speciation in seawater samples was consistently determined by competitive ligand equilibration–cathodic stripping voltammetry (CLE–CSV). The proposed apparatus showed several advantages: (1) 20-fold reduction in sample volume (the sample size is lowered from 120 to 6mL for the CLE–CSV procedure); (2) decrease in analysis time due to the reduction in purging time up to 2.5 fold; (3) 20-fold drop in reagent consumption. Moreover, the analytical performances were not affected: similar detection capabilities, precision and accuracy were obtained. Application to sample of limited availability (e.g. porewaters, snow, rainwater, open ocean water, biological samples) and to the description of high resolution temporal trends may be easily foreseen.

Design of sample holder for in operando XAS of oxidation state changes in La1−xSrxMnO3±δ electrodes

The design and construction of a sample holder for in operando X-ray absorption spectroscopy on solid oxide electrodes, like for instance the lanthanum strontium manganite electrodes, is explained. The sample holder is mounted in a test-cell, which is also described together with some preliminary test-results from temperature measurements and electrochemical characterisation performed on a "dummy" sample in the test cell. The test-cell is a modified version of a test-cell previously designed in our laboratory, and will in the future be used for X-ray absorption experiments on solid oxide electrodes.

Measuring the inverse magnetostrictive effect in a thin film using a modified vibrating sample magnetometer

A method for measuring the magnetostriction of thin films using a vibrating sample magnetometer is described. We describe the design of a custom sample holder to apply an adjustable bending stress to the sample during measurement and observe the resulting change in the M-H loop.

A cheap and quickly adaptable in situ electrical contacting TEM sample holder design

In situ electrical characterization of nanostructures inside a transmission electron microscope provides crucial insight into the mechanisms of functioning micro- and nano-electronic devices. For such in situ investigations specialized sample holders are necessary. A simple and affordable but flexible design is important, especially, when sample geometries change, a holder should be adaptable with minimum effort. Atomic resolution imaging is standard nowadays, so a sample holder must ensure this capability. A sample holder design for on-chip samples is presented that fulfils these requisites. On-chip sample devices have the advantage that they can be manufactured via standard fabrication routes.

A 350 mK, 9 T scanning tunneling microscope for the study of superconducting thin films on insulating substrates and single crystals

We report the construction and performance of a low temperature, high field scanning tunneling microscope (STM) operating down to 350 mK and in magnetic fields up to 9 T, with thin film deposition and in situ single crystal cleaving capabilities. The main focus lies on the simple design of STM head and a sample holder design that allows us to get spectroscopic data on superconducting thin films grown in situ on insulating substrates. Other design details on sample transport, sample preparation chamber, and vibration isolation schemes are also described. We demonstrate the capability of our instrument through the atomic resolution imaging and spectroscopy on NbSe2 single crystal and spectroscopic maps obtained on homogeneously disordered NbN thin film.

A versatile elevated-pressure reactor combined with an ultrahigh vacuum surface setup for efficient testing of model and powder catalysts under clean gas-phase conditions

A small-volume reaction cell for catalytic or photocatalytic testing of solid materials at pressures up to 1000 Torr has been coupled to a surface-science setup used for standard sample preparation and characterization under ultrahigh vacuum (UHV). The reactor and sample holder designs allow easy sample transfer from/to the UHV chamber, and investigation of both planar and small amounts of powder catalysts under the same conditions. The sample is heated with an infrared laser beam and its temperature is measured with a compact pyrometer. Combined in a regulation loop, this system ensures fast and accurate temperature control as well as clean heating. The reaction products are automatically sampled and analyzed by mass spectrometry and/or gas chromatography (GC). Unlike previous systems, our GC apparatus does not use a recirculation loop and allows working in clean conditions at pressures as low as 1 Torr while detecting partial pressures smaller than 10(-4) Torr. The efficiency and versatility of the reactor are demonstrated in the study of two catalytic systems: butadiene hydrogenation on Pd(100) and CO oxidation over an AuRh/TiO2 powder catalyst.

A novel mass spectrometry system for helium-4 measurement

Here we report a novel mass spectrometry measurement system (MSHE4) developed at State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences for quantifying helium-4 contents of geological mineral samples. The MSHE4 system consists of seven units, a high vacuum level generating unit, a gas purified unit, a laser heating unit, a pneumatic valve unit, an automatic control unit, a gas standard unit and a quadropole mass spectrometer unit. The unique software package, developed using LabVIEW for embedded system, allows users to control the full measurement sequences. Results from a test of the Durango apatite sample are used to illustrate the performance of the new MSHE4. We show that the constructed MSHE4 system is able to accurately measure helium-4 contents of apatite mineral, which in turn can be used to quantify the low temperature thermochronology of geological minerals in combination with measurements of uranium and thorium by LA-ICP-MS. The configuration of the MSHE4 system has following advantages: smaller volume of pipeline for gas purification, easier operation of graphic user interface for measurements, and more compact design of sample holder for single grain measurements. The separate step-heating unit can be mounted to the system smoothly. The MSHE4 system can be used for measurement of noble gases from minerals, and in turn thermochronology applications for geochemists.

Electromechanical Behavior of Bronze $\hbox{Nb}_{3} \hbox{Sn}$ Strands Under Wide Range Pure-Bending

A series of experiments to study the electromechanical performance of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn superconducting wires under large pure bending strain has been performed. Based on the previously developed pure-bending sample holder beam for applied strains up to 0.8 %, an improved beam was designed to cover the entire range up to nominal bending strains of 1.25% on the strand surface. Critical current measurements as a function of bending strain are discussed for bronze strands from EAS and Hitachi. The samples were mainly tested at 15 T. High deformation and Lorentz load effects were studied through a finite element model structural analysis. Good agreement between finite element model and experimental results was found. Full range bending strain and reversed current tests were performed and it was found that for Lorentz loads below 3 kN/m the sample holder design could be appropriately used to cover a bending range from 0.6 % to 1.25% nominal strain on the surface of a 0.81-mm-diameter strand.

Modelling and optimization of IR cell devoted to in situ and operando characterization of catalysts

CFD modelling and tracer experiments were performed in order to improve the design of sample holder used for transmission IR experiments in flow conditions.The complexity of gas velocity field evidenced for the usual circular geometry is avoided with an alternative geometry. A new geometry involving a square pellet, multiple inlets and outlets and specific sample holder proposed in the present study leads to a more homogeneous gas velocity in the vicinity of the catalyst surface as shown by modelling with COMSOL. Experimental measurements of local tracer concentrations in different places of the reactor during transient experiments confirmed more homogeneous tracer distribution in the reactor mainly due to multiple inlets and outlets. Consequences of the presence of dead volumes identified by modelling were also examined and discussed.

Effect of Electron Beam Irradiation and Heating on the Structural Stability of Sulphide-Filled Carbon Nanotubes

In recent years there has been an increased interest in characterisation methods capable of evaluating the response of nanostructured materials such as quantum dots and nanotubes to externally applied stimuli. However, due to issues concerning sample homogeneity and non-uniform orientation, the study of collective responses can lead to ambiguous results. Therefore, it is crucial to perform a complementary evaluation at the single nanostructure level which requires the use of sophisticated analytical instrumentation. In addition to high spatial resolution, the equipment employed must permit sample manipulation and real-time imaging of the in situ stimulus response. Transmission electron microscopes (TEM) observe all these requirements. Furthermore, novel developments in sample holder design and manufacturing have opened a window to an unprecedented range of new in situ experiments. As a result, varied reports are increasingly populating the in situ TEM literature examining such different matters as temperature-related structural phase changes of nanoparticles or dopant diffusion in nanoscaled batteries.

New sample holder geometry for high precision isotope analyses

Secondary ion mass spectrometry is applied to a wide range of Geoscience applications because of its capability to provide direct in situ measurement of elemental and isotopic composition. The CAMECA IMS 1280 and 1280‐HR are large geometry ultra‐high sensitivity ion microprobes that provide excellent precision and reproducibility for isotope ratio measurements. A precision at the tenth permil level is routinely achieved for the measurement of 18O/16O ratio from 10 µm spots using multicollection Faraday Cups. However, analytical artifacts related to the surface topography and to the location of the analysis in the sample (X–Y effects) are known to bias the precision for isotope analysis. The X–Y effects have been investigated using a CAMECA prototype sample holder design. Results show a significant improvement in terms of reproducibility for analyses performed over a large area of the sample. Detailed analytical data using the new sample holder will be presented. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Note: A sample holder design for sensitive magnetic measurements at high temperatures in a magnetic properties measurement system

A sample holder design for high temperature measurements in a commercial MPMS SQUID magnetometer from Quantum Design is presented. It fulfills the requirements for the simultaneous use of the oven and reciprocating sample option (RSO) options, thus allowing sensitive magnetic measurements up to 800 K. Alternating current susceptibility can also be measured, since the holder does not induce any phase shift relative to the ac driven field. It is easily fabricated by twisting Constantan© wires into a braid nesting the sample inside. This design ensures that the sample be placed tightly into a tough holder with its orientation fixed, and prevents any sample displacement during the fast movements of the RSO transport, up to high temperatures.

Design of Sample Holders for Soil Experiments Using THz Spectroscopy

Terahertz spectroscopy (THz) is a brand-new radiation source with many unique advantages. It owns many potential applications in all area. An experiment was carried out on soil heavy metal detection using THz in Jun., 2010 at Oklahoma State University. Two types of sample holders (1.5mm thickness and 3 mm thickness) were designed based on specific requirements and applications in this paper. The optical material, size, thickness of the sample, thickness of the side-wall, property of samples for holding, adhesive materials, cost were discussed in detail; then, an integrated description were given and a 3-D model was established. Real holders were manufactured based on the former design and their THz characteristics were measured. At last, the holders were used in the current soil heavy metal detection experiment. The results showed that, the designed holders showed low absorption of THz and low reflection. Two thickness samples holders all performed well in the experiments, however, for the soil measurement, the sample information could not be completely collected before echo wave came. The 1.5mm thickness holder was selected in our experiment. The designed sample holders are feasible and this research provides a good solution for the difficulties we met in our experiment.

A Novel Approach to the In Vitro Hydrodynamic Study of the Aortic Valve: Mock Loop Development and Test

The aortic root functional unit (ARFU) is a complex structure whose functions are strictly dependent on the biomechanical interaction among each of its anatomically defined elements. The classical approach to the in vitro study of aortic hydrodynamics does not take this complexity into account. We propose a novel methodology based on the possibility to house whole natural ARFU samples in a purposely designed pulsatile mock loop, allowing for aortic surgery simulation. To point out the usability and potentialities of the device, the mock loop was tested with untreated porcine ARFU samples and with one ARFU prosthesized with a state-of-the-art bioprosthesis. The sample holder design was proved to allow the clinician to house and treat the ARFU sample in the mock loop with easiness and repeatability. The valve leakage with the prosthesized ARFU was comparable with literature data, and Effective orifice areas were consistent with the constructor's data. In contrast, the recorded pressure drops exceeded the data from the manufacturer and were quite aligned with in vivo postop echo-Doppler data acquired in implant recipients. This result suggests that our apparatus and methodology provide a way to investigate aortic hydrodynamic phenomena that resemble in a close way to those taking place in the final recipients' circulation.