Diamond-Coated Plasma Probes for Hot and Hazardous Plasmas

Plasma probes are simple and inexpensive diagnostic tools for fast measurements of relevant plasma parameters. While in earlier times being employed mainly in relatively cold laboratory plasmas, plasma probes are now routinely used even in toroidal magnetic fusion experiments, albeit only in the edge region, i.e., the so-called scrape-off layer (SOL), where temperature and density of the plasma are lower. To further avoid overheating and other damages, in medium-size tokamak (MST) probes are inserted only momentarily by probe manipulators, with usually no more than a 0.1 s per insertion during an average MST discharge of a few seconds. However, in such hot and high-density plasmas, their usage is limited due to the strong particle fluxes onto the probes and their casing which can damage the probes by sputtering and heating and by possible chemical reactions between plasma particles and the probe material. In an attempt to make probes more resilient against these detrimental effects, we tested two graphite probe heads (i.e., probe casings with probes inserted) coated with a layer of electrically isolating ultra-nano-crystalline diamond (UNCD) in the edge plasma region of the Experimental Advanced Superconducting Tokamak (EAST) in Hefei, People’s Republic of China. The probe heads, equipped with various graphite probe pins, were inserted frequently even into the deep SOL up to a distance of 15 mm inside the last closed flux surface (LCFS) in low- and high-confinement regimes (L-mode and H-mode). Here, we concentrate on results most relevant for the ability to protect the graphite probe casings by UNCD against harmful effects from the plasma. We found that the UNCD coating also prevented almost completely the sputtering of graphite from the probe casings and thereby the subsequent risk of re-deposition on the boron nitride isolations between probe pins and probe casings by a layer of conductive graphite. After numerous insertions into the SOL, first signs of detachment of the UNCD layer were noticed.

Characterization of a Chromium (III) Ion Probe and its MOF-Supported Material

In order to explore more functional supported probe material, the ultraviolet absorbance together with fluorescence properties of a probe with the structure of salicylaldehyde Schiff-base in various solvents and pHs were investigated after its synthesis. When the concentration of Cr3+ ion was in the range of 3~7×10-5 mol•L-1, the complex reaction between the probe and Cr3+ could be used for quantitation of the latter, which was developed by UV absorbance intensity of the complex and the concentration of Cr3+ ion. Ultraviolet analytic results determined that they were complexed in the molar ratio of 1:1. Finally, the MOF-supported probe material was successfully synthesized for further application, which realized the immobilization of the probe through simple operations.

A method for determining the local mechanical properties using nanoindentation in oscillating mode

A new method of processing of data obtained using atomic force microscopy (AFM) in the oscil-lating nanoindentation mode is proposed. The model of the AFM probe on elastic beam (canti-lever) interaction with a sample is developed. In addition to the static load, applied on a base of the cantilever, a force modulation, according to a harmonic law, is set. This approach makes possible to take into account not only the force of the probe-material interaction but also the phase shift of the cantilever oscillations with respect to a given harmonic signal on the cantilever base as well as the amplitudes ratio of these oscillations. This information allows the presence of the viscosity in the material evaluating. The advantage of the oscillatory regime over quasistatic indentation was shown. It consists in the possibility to exclude the influence of irreversible pro-cesses (plastic, brittle fracture in the material) on the result of the experiment and to reveal the presence of the time dependent behavior. It is shown that the model contains a small amount of constants; methods for their determination are proposed. The calculations, performed using the developed model, made it possible to make a number of recommendations on choosing the can-tilever stiffness to obtain the most informative experimental results. This approach seems per-spective in studying materials with a high degree of stiffness inhomogeneity, including the deter-mination of the local properties of filled nanocomposites near filler particles.

PERMASALAHAN PENUNTUTAN TERHADAP PELAKU PENYALAH GUNA NARKOTIKA DI WILAYAH HUKUM KEJAKSAAN NEGERI PADANG

In the case handling of narcotics abuse, the public prosecutor at the Padang District Attorney’s Office only proceed articles that had been suspected by the investigator, without proving accurately the status of the narcotics abuser. This research is aiming to understand the handling of narcotics abuse and its issues during the prosecution process at the Padang District Attorney’s Office. This research is using empirical normative research methodology. Based on the research, the public prosecutor at the Padang District Attorney’s Office did not precisely investigate and probe material evidence related to the status of the perpetrators of narcotics abuse. As a result, in indictment letter, the case of narcotics abuses always being overlaid with the harsher indictment articles, namely Article 111, 112, or 114 of Law Number 35 of 2009, which detention be applicable to the perpetrators. Supposing only a single indictment of article 127 is applied, the perpetrator of the narcotics abuse shall not be detained as stipulated in Article 21 paragraph (4) of KUHAP. This condition is clearly detrimental to the narcotics abuser, especially those people in addiction or victims of narcotics abuse, where they should be placed at the Rehabilitation Institute. Due to the absence of public prosecutor's meticulous attempt in probing material evidence related to the status of the perpetrators of narcotics abuse, it may cause false sentence declared by the judge.

Active microrheology

Active microrheology uses external forces (most typically magnetic or optical) to force microrheological probes into motion. These techniques short-circuit the Einstein component of passive microrheology. Active microrheology provides an additional handle to probe material properties, and has been used both to extend the range of materials amenable to microrheological analysis, and to examine material properties that are inaccessible to passive microrheology. Three main topics are presented: the use of active microrheology to extend the range of passive microrheology, while maintaining many of the advantages (small sample size, wide frequency range, etc.); its use to complement passive microrheology in active systems, which convert chemical fuel to mechanical work, in order to elucidate the power provided by molecular motors, for instance; and its application (and potential limitations) to investigate the non-linear response properties of materials, including shear thinning and yielding.

Recent Progress in CMM-Based Form Measurement

Form standards with different profile geometries were measured using 3- and 4-axis scanning on a 3D CMM prototype with a precision rotary table. Physical boundary conditions, including probing force, probe diameter, probe geometry, probe material, and scanning speed, were varied, and then the results were analyzed. Some results were found to be equivalent to those obtained using form measuring machines. Limitations of the current implementation of this technique are discussed.

Nano-rheology of hydrogels using direct drive force modulation atomic force microscopy

A quantitative and novel nanoscale viscoelastic spectroscopy tool for soft matter was developed. The study highlights the transition in the probe–material contact mechanical behavior of hydrogels especially when the applied strain rates and the material relaxation become comparable.

Research of Sensing Probe Material in Wet and Dry Soil

Soil moisture sensor probe is the basic and key part of the automated water-saving irrigation equipment. It can measure soil moisture accurately and in real-timely, while metal probes have a serious problem of corrosion and passivation as working in the soil which is a severe environment of the soil of high humidity and complex chemical compositions. Graphite gelling of different content of graphite composite material under both wet and dry conditions, the experimental study, by testing the experimental data of its resistivity contrast to identify the proportion of the composite material of graphite content suitable for the production of a new probe.

Study on the Graphite-Based Cementitious Material for the Soil Moisture Detective Probe

Soil moisture detective probe is an important part of automatic irrigation system. Soil moisture probe is usually made of metal material which is easy to be corroded and passivated as long-term working in the damp soil, especially containing acid, alkali and salt. We developed a new soil moisture probe material - the graphite-based cementitious material. The mechanical properties and the conductive properties of the material were tested and we found the graphite-based cementitious material which contains 30% to 50% of graphite could be an applicable material for the soil moisture probe.